Econ_100_Lecture_1

合集下载

生态平衡英语讲座

生态平衡英语讲座Ecological balance is a crucial aspect of our planet's health and sustainability. It refers to the delicate equilibrium between various organisms and their environment, ensuring the smooth functioningof ecosystems. 生态平衡是地球健康和可持续性的关键方面。

它指的是各种生物体与其环境之间的微妙平衡，确保生态系统的顺畅运行。

When there is a disruption in this balance, it can have far-reaching consequences on the environment and all living beings. Human activities such as deforestation, overfishing, and pollution have severely impacted ecological balance, leading to biodiversity loss and habitat destruction. 当这种平衡被打破时，会对环境和所有生物体产生深远的影响。

人类活动，如森林砍伐、过度捕捞和污染，严重影响了生态平衡，导致生物多样性丧失和栖息地破坏。

One of the key components of ecological balance is the food chain, where each organism plays a crucial role in maintaining the balanceof the ecosystem. For example, predators help control the population of prey species, preventing them from overpopulating and depleting resources. 生态平衡的一个关键组成部分是食物链，其中每个生物体在维持生态系统平衡方面发挥着至关重要的作用。

【2020最新智库】ECO中心ECO作业训练讲义(1)

ECO中心ECO作業訓練课件一、目的本课件之目的于于說明ECO系統工具處理的相關操作，為后補人員或新進人員進行ECO系統教育，通過學習使其能于ECO發生時，對工具及WIP板子進行處理作業。

二、範圍此课件適用于有ECO時，配合ECO系統各作業規範對ECO文件進行處理，舊生產工具及WIP板子的處理。

便于ECO作業人員學習掌握ECO時舊生產工具的處理及ECO時WIP板子的處理作業。

三．說明制前工程課的功能=設計+制具+工具管理。

ECO中心主要進行有ECO時，進行工具的管理及處理作業，從而達到工具的有序流動，及現場生產工具的正確使用。

故ECO處理作業是制前工程課工作的一個重要項目。

ECO系統對于PCB專業知識要求較高，需具備相關設計知識。

所以應結合ECO作業規範和設計準則及設計作業規範學習。

此课件主要為操作步驟說明，若與作業規範有抵觸，作業規範優先于此訓練课件，且希望能指正，便于修訂。

第一節概論ECO(ENGINEERINGCHANGEORDER)中心是制前工程課的一個作業單元，主要進行ECO處理。

1制前工程課功能﹕制前工程功能=P.C.B.生產工具之設計+制具+變更處理2ECO中心職責﹕2-1ECO內容檢核2-2發料控制系統管制2-3ECO時工具及WIP板子處理WIP查詢WIP板子及舊工具處理ECO文件處理ECOFOLLOW-UP多料號ECO管制無訂單ECO管制報廢ECO處理ECOWIP現場流程單更改、更換3ECO中心ECO時涉及處理之PCB生產工具有（指由制前工程課提供之生產工具）3-1流程單3-2工作底片﹕內存底片、外層底片、抗鍍金底片、綠漆曝光底片、印字底片、檔墨底片、塞孔底片、孔位底片3-3鑽孔&切型程式3-4O/S、P/G模具3-5電流條件（電鍍）4作業常用名詞簡介4-1PCB(PRINTCIRCUITBOARD):印刷線路板4-2ECO(ENGINEERINGCHANGEORDER):工程更改通知單4-3A/W(ARTWORK):底片4-4W/F(WORKINGFILM):工作底片4-5SPEC(SPECIFICATION):品質規範4-6PATTERN:板面圖形4-7PTH(PLATETHROUGHHOLE):電鍍孔4-8N-PTH:非電鍍孔4-9P/N(PARTNO.):料號4-10SMT(SURFACEMOUNTINGTECHNOLOGY):表面粘著技術4-11S/S(SILKSCREEN):印字4-12S/M(SOLDERMASK):綠漆4-13G/F(GOLDFINGER):金手指4-14PAD:焊墊、園墊4-15L/W(LINEWIDTH):線寬4-16L/S(LINESPACING):線距4-17A/R(ANNULARRING):孔環4-18GNDLAYER:接地層4-19VCC/POWERLAYER:電壓層4-20SIG(SIGNAL)LAYER:線路層4-21COUPON:板邊式樣4-22V-CUT:V型切槽4-23SLOT:橢圓孔（槽）4-24D/F(DRYFILM):干膜4-25LAY-UP:疊板4-26COMP（COMPONET）SIDE:零件面4-27SOLDERSIDE:焊錫面5ECO簽發時機ECO簽發時機為PCB規格、資料需變更或生產工具需要更改時。

ECON10040213_426061E6[1]

Analysis of the Implementation of Fair Value in ChinaXiaoyan LiuSchool of Business Administration, North China Electric Power UniversityBeijing, P. R. ChinaTel: 86-10-80798426 E-mail: lliu716@Lin WangSchool of Business Administration, North China Electric Power UniversityBeijing, P. R. ChinaTel: 86-10-80798426 E-mail: wanglin1987915@AbstractSince the application of New Accounting Standards, lots of attention has been concentrated on fair value measurement. This paper is an analysis of the implementation of fair value in China listed companies through an empirical method. By using the data of listed companies in 2007-2008, which belongs to the security markets of Shanghai and Shenzhen, we summarize the situation of applying the fair value measurement in listed companies, the effects of fair value measurement in profit aspect, as well as the problems to be resolved. The analysis is very helpful for both further researches on implementation guidance, and applying the fair value measurement appropriately in China listed companies.Keywords: Fair Value Measurement, Listed Company, New Enterprise Accounting Standards, Financial Instruments With the widely application of the international accounting standards, the new accounting standards for business enterprise in China were released in 2006, and applied from January 1st 2007 to reflect the economic situation more relatively. Among the new accounting standards, adopting fair value as a measurement tool is one of the biggest highlights both in theory and practice. How has it been used since 2007? In this paper, we analyze the implementation of fair value, using the data of listed companies in China, and summarize the problems in applying fair value.1.The application of fair value measurement in listed companies in ChinaAccording to the New Enterprise Accounting Standards, fair value is defined as the amount that an enterprise would pay or receive to transfer an asset or a liability in an arms length transaction, between knowledgeable parties. Fair value is adopted in many standards such as “the recognition and measurement of financial instruments”, “the biological assets”, “debt restructuring”, “merger”, and “exchange of non-monetary assets”.In the standard of “the recognition and measurement of financial instruments”, fair value is required to be adopted in initial recognition of financial assets. In the subsequent year-end measurement of financial assets, the available for sale securities and trading securities are required to use fair value as measurement tool. As shown in figure 1, in year 2007, among the 1328 listed companies, 362 companies held trading securities, covering 27% of the total; 345 companies held available for sale financial assets, covering 26% of the total, 140 owned the held-to-maturity investment, occupying 11%. In the annual reports of 2007, all of the listed companies holding financial instruments stated that they adopted fair value in related financial instruments measurement according to the new enterprise accounting standard, and disclosed the recognition and the subsequent measurement of financial assets and liabilities in notes. From the disclosure of 2007 annual report Shanghai market, 256 companies have balances in the account of gain or loss from changes in fair value, including the 169 companies owning gains and the remaining 87 companies holding losses. Comprehensively, the gains and losses from change of fair value mainly come from the trading securities and investment real estate.Of the 1328 listed companies, 761 held the investment real estate, occupying 57% of the overall. But in the investment real estate holding companies, historical cost measurement is adopted in most companies, Only 10 companies’ used fair value measurement, occupying little 1.13%. Among the 10 companies, 5 companies disclosed that the fair value are re the results of asset appraisal in the notes to financial reports, the other 5 companies gained fair value base on market transaction price of similar assets.2.The effect of fair value measurement on company performanceThe introduction of the fair value measurement affects many aspects of enterprise such as operating performance, earnings management and financial structure at different level. This paper mainly aims at the fair value measurement applications and its effects on enterprise performance.1842.1 The overall effects of fair value measurement on listed companiesBy August 31st, 2008, 1619 companies of Shanghai and Shenzhen market disclosed semi annual reports, with an overall ̞553.30 billion net income, excluded Gold Molybdenum (601958) for its incomparability. It increased by 19.31%. The account “gains or loss from the changes in fair value” existed in 381 companies, totaling ̞244.95 billion losses due to the changes in fair value, which was 309.52% of last year. Compared with the large losses, these companies listed ̞116.91 billion gains on this item in 2007. As announced in the first three season reports of 2008, only less than 60 listed companies gained profits from securities investment, most companies were suffering with negative gains from changes in the fair value, and more than 20 companies' losses exceeded ̞1 billion Yuan. The total of changes in the fair value of whole listed companies is nearly ̞2.9 billion.By 2009 April 15, 307 of 1047 companies which have their annual reports published disclosed information about gains or losses from changes in fair value, totaling a loss of ̞258.14 billion, compared with ̞128.3 billion gains from changes in fair value of the same 1047 companies in 2007. The ratio of gains or losses from investment and changes in fair value to total income before income taxes is 17.09%, 22.84% to with net income.2.2 Case studyWe take China International Marine Containers (Group) Ltd (CIMC) (000039) as a case to show the effects on company performance in the following. Table 1 shows us the related performance index information such as Revenue, Operating Income and Net income of CIMC Group in 2004-2008 annual reports. In the first three years from year 2004 to 2006, as Figure 2 and Figure 3 shown, Revenue, Operating Income and Net income, all of the performance indices of the group increased smoothly; in 2007, the performance increased greatly, and conversable in 2008 it began to decline, especially the net income declines more sharply than the revenues and operating income. From the overall situation, fluctuations of performance of CIMC Group in year and 2008, in which fair value measurement has been applied are significantly greater than those of the previous year before 2007.Table 2 summarizes the amounts and ratios of performance of CIMC Group in year 2007 and 2008, in which year the new accounting standards, especially the fair value measurement, have been were applied. In year 2007, the gains from changes in fair value amounted to ̞2.74 billion, occupying 7.93% of operating income, 8.66% of the net income of the current year. In the contract, In year 2008, the losses from changes in fair value amounted to ̞4.38 billion, occupying 24.3% of operating income, 31.13% of the net income of the current year.By analyzing the operating details of CIMC Group in 2008, things are clear that the ̞473.27 billion revenue earned during was 2.94% dropped than last year, and the ̞14.07 billion net income in 2008 was 55.55% dropped than last year. The main reason for the revenue drop lied in the dry containers discontinuation happened in the fourth quarter of 2008. As far as the sharply falling of net income is concerned, the two main reasons are important: one is the provision for the of dry containers discontinuation for ̞6.99 billion, and the other is the stock write-down, which resulting the gains from changes in fair value fell sharply. Why net income decline far outweigh the revenue? Among these two reasons, the ̞4.38 billion loss from changes in fair value play a more important role, which is reaching 31.13% of the net income. This is apparently different from the gains earned in 2007. Furthermore, from the data of annual reports in 2007 and 2008, we can see that the decline in value of trading securities and derivatives during the reporting period is responsible for the losses from changes in fair value.3.Problems in fair value applyingIn applying the fair value measurement, there are still lots of problems. Four main factors that prevent applying fair value measurement properly are concluded as follow:3.1 Lack of complete theory system and operational guidelinesAlthough the new accounting standards set up basic principles for the recognition and measurement of fair value, detailed theory framework and implementation guidelines are still lacked. For example, in the new accounting standards there is not any detailed principle about how to determine the fair value of assets from the similar asset transaction, such as in what kind of market, in what time, and which price to choose. In the annual reports of listed company in 2007 and 2008, some companies stated that in many subjects they have followed the new accounting standard, by using the price of similar assets in the active market quotation, to determine the fair value, In fact, due to the lack of standards. But because there is no publicly accepted principles, the fair value amounts largely depends on evaluation techniques, methods and professional judgment adopted by accounting personnel, especially those that need to use evaluation of the future cash flow of assets, the estimated amounts would differ greatly due to different date and the discount rate.3.2 Inadequate disclosure of fair value informationIn the annual reports of the listed companies in China, little information related to the process of determining the fair value is found. Although most companies disclosed the amounts of trading securities and other financial assets and financial liabilities, information on how to determine the fair value of these assets and liabilities, such as the valuation185of the concrete method and parameters of selection, has not been fully disclosed in the notes. Furthermore, in the financial statements some listed companies, important items such as the major trading, important matters, important accounting policy, and accounting estimates requested by the new accounting standards have been omitted. Therefore, disclosure about whether fair value measurement after the major trading has been applied can not be found.3.3 Lack of effective market environmentAccording to the new accounting standards, the access of fair value should be in an active, completely competitive market condition. It is required the knowledgeable parties to participate willingly in the transactions, in which information asymmetry should be as far as possible, and any commodity market price can be open to access, and thus they can trade transactions risk factors into consideration, and determine the transaction price properly.Although China's market economy has been established, the transition of the economic system has not been completed. There are still many disadvantages of the market condition for obtaining fair value. For instance, non-market factors still exists, non-monetary transactions between enterprise's are not regular, the markets for securities trading, property right trading market, and production material are not mature, and so on. Therefore, due to mature market condition suitable for the application of fair value, the soil and the environment, is not mature, the applying of fair value measurement in practice is not easy.3.4 Lack of highly qualified and skillful accounting personnelB ecause of the difficulty of the access of fair value, the professional skill and professional judgment ability of accounting personnel are requested put forward higher request. There are about 12 million accounting professionals in China, about 80% of which are workers with inferior practicing ability, who have not been educated systemic accounting theory. It is difficult for them to correctly understand the definition of fair value measurement, let alone to use. Therefore, there will be a long way for them to increase the professional skill and professional judgment ability. The low quality of accounting personnel in businesses is considered one of the problems to be resolved in the reasonable application of the fair value.4. SummaryB ased on the above analysis of data deriving from the annual reports of China listed companies in 2007-2008, we summarize the application situation of fair value measurement and its effects on performance aspects of company. In addition, we also analyze the problems existing in applying the fair value measurement.(1) Fair value has been adopted by China listed companies widely and smoothly. With the application of the new accounting standard, fair value measurement has been adopted in many standards, the recognition and measurement of financial instruments is the case in point. Nearly one third of companies measured trading securities, the typical financial asset, at fair value.(2) Fair value measurement affects the Net Income by the account gains or loss from change in fair value, the greater the fluctuations of market, the larger the effects. From this aspect, fair value is like a double-edged sword, that is, it can sensitively reflect the market situation. When the market is in prosperity time, fair value can boost the performance; in contrast, when the market setback, it also can suffer the listed company with great loss. Performances in 2007 and 2008 are examples in the above two cases.(3) In applying fair value measurement, there are still some problems to be resolves in the future. Both problems in the external environment such as system and market environment and internal factors are considered. There is a long way to go until qualified accounting personnel are developed, and related information about fair value measurement are fully disclosed.ReferencesXie, Shifen. (2004). Fair Value: Research on International Accounting Frontier Problem. Hunan Renmin Press. Ministry of Finance. Accounting Standards for Business Enterprises. (2006). Economic Science Press.Wang, Jiancheng, Hu Zhenguo. (2007). The Present Situation of Fair Value Measurement and Research on Related Issues. Accounting Research, (5):10-16.FASB. (2005). Fair Value Measurement. .FASB. (2006). SFAS 157, Fair Value Measurement. .186187Table 1. Performance of CIMC Group in 2003-2008 (Unit: Billion Yuan) 2003 2004 2005 2006 2007 2008Revenue 138 265.68 309.59 331.68 487.6 473.27Operating Income 9.58 30.13 30.23 27.6 34.57 17.67Net Income 6.83 23.89 26.69 27.72 31.65 14.07Table 2. Proportion of Gains or Losses from Changes in Fair Value to Performance of CIMC Group (Unit: B illion Yuan)2007 2008 Gains or losses from changes in fair value (1) 2.74 -4.38Operating Income (2) 34.57 17.67Net Income (3) 31.65 14.07Ratio:(1)/ (2) 7.93% 24.30%Ratio: (1) /(3) 8.66% 31.13%Figure 1. Distribution of Financial Instruments in 2007 of CIMC GroupFigure 3. Trend of Operating Income and Net Income in 2004-2008 of CIMC Group。

多伦多大学大一经济学 Lecture 01 - ECO100

Assumptions are the foundations on which the
model is built Assumptions allow for a simplification of the real
world
Implications are the outcome of the model Implications of the model depend on the assumptions
relationship downward
The l ti hi between t variables that move i Th relationship b two i bl h in the opposite direction is called a negative Such a relationship is shown by a line that slopes
are used in order to satisfy human wants or needs
Resources are characterized for being scarce and human wants for being unlimited
There are 3 main types of resources: natural resources (land, minerals, water, etc.) capital resources ( l machinery, buildings, etc.) i l (tools, hi b ildi ) human resources (mental and physical)
© Gustavo Indart
Slide 10

Lecture #1

Most Americans live in an Urban Area
Other regions of the world are rapidly urbanizing
New CBSAs combine MSAs
Portal to Census Data: American FactFinder ()
Bay Area Counties and Municipalities
Census geography built up from the Census “Block” level
U.S. Census definitions
– Entire U.S. mapped into Census blocks, which are grouped into larger “block groups” and “tracts” – Urban area: population density >1,000/sq. mi. – Urban population: people living in urban areas – Metropolitan area: urban core of at least 50k people, tight commuting connections between urban areas. – Micropolitan area: urban core of 10k to 50k people – Principal city: largest municipality in metro area
Syllabus
• • • • • • • • Why Do Cities Exist? (2 weeks) The Distribution of City Sizes and Place Based Policies (2 weeks) Bid-Rent Curves and Land Use (2 week) Housing (2 weeks) Zoning (1 week) Neighborhood Choice and Segregation (1 week) Local Public Economics (3 weeks) Transportation (2 weeks)

1 An efficient steroid pharmacophore-based strategy to identify new aromatase inhibitors

Original articleAn efﬁcient steroid pharmacophore-based strategy to identify new aromatase inhibitorsMarco A.C.Neves a ,Teresa C.P.Dinis b ,Giorgio Colombo c ,*,M.Luisa Sa´e Melo a ,**aCentro de Estudos Farmaceˆuticos,Lab.Quı´mica Farmace ˆutica,Faculdade de Farma ´cia,Universidade de Coimbra,3000-548Coimbra,Portugal bCentro de Neurocieˆncias,Lab.Bioquı´mica,Faculdade de Farma ´cia,Universidade de Coimbra,3000-548Coimbra,Portugal cIstituto di Chimica del Riconoscimento Molecolare,CNR,20131Milano,Italya r t i c l e i n f oArticle history:Received 20November 2008Accepted 7May 2009Available online 19May 2009Keywords:Pharmacophore modeling Virtual screening Aromatase inhibitors Breast cancera b s t r a c tAromatase,an enzyme involved in the conversion of androgens into estrogens,is an important target for the endocrine treatment of breast cancer.Aromatase inhibition is usually achieved with steroids struc-turally related to the substrate of catalysis or,alternatively,with azole non-steroid compounds.Substituted androstenedione derivatives with D 1,D 6and D 1,6unsaturations and 6-alkyl/6-phenyl aliphatic substitutions,are among the most potent steroid aromatase inhibitors known to date.In this paper we have combined the common pharmacophoric and shape features of these molecules into a new pharmacophore model,useful for virtual screening of large compound databases.Small subsets of the best ﬁtting anti-aromatase candidates were extracted from the NCI database and experimentally tested on an in vitro assay with human placental aromatase.New potent aromatase inhibitors were identiﬁed such as compounds 8and 14.Considering the lack of a crystal structure for the aromatase enzyme,this ligand-based method is a valuable tool for the virtual screening of new aromatase inhibitors.Ó2009Elsevier Masson SAS.All rights reserved.1.IntroductionEstrogen deprivation is an effective approach for the endocrine treatment of hormone sensitive breast cancer in postmenopausal women.Aromatase,the enzyme responsible for the conversion of androgens into estrogens,is therefore an important pharmacolog-ical target [1].The aromatization reaction is a three-step trans-formation involving two hydroxylations at the 19-methyl group of androstenedione and testosterone,and a ﬁnal oxidative decar-bonylation.Each reaction consumes a single mole of molecular oxygen and NADPH [2].Since androstenedione is the preferred substrate for the enzyme [3],the initial development of aromatase inhibitors was focused on this basic scaffold,substituted at several positions.Most of these molecules are competitive inhibitors and bind to the same activesite cavity as the natural substrate [4].Formestane and exemestane,second and third generation aromatase inhibitors,are successful examples of steroid aromatase inhibitors developed with this approach.Indeed,both compounds have been approved for clinical use [5,6].Other examples of potent inhibitors include androstene-dione derivatives with D 1,D 6and D 1,6unsaturations and 6-n -alkyl or 6-n -phenyl aliphatic substitutions [7–10].These compounds high-lighted the presence of a hydrophobic pocket close to the C6posi-tion of the steroid nucleus.The length and shape of this substitution were found to be critically important to the activity [11].Besides competitive aromatase binding,several steroid aroma-tase inhibitors are converted by the enzyme into reactive inter-mediates,which are able to cause time-dependent inactivation.These compounds are known as mechanism-based inactivators.The activation step is triggered during a normal catalytic process and depends on the presence of NADPH.Typically,a reactive electrophilic intermediate is formed and immediately reacts with a nucleophilic residue within the active site [12].Although a crystallographic 3D structure of the aromatase enzyme is still not available,several X-ray structures of homologous mammalian and human cytochrome P450enzymes [13–16]have been used as templates to build homology models [17–19].Key atomic details that ultimately determine molecular interactions were identiﬁed in structure-based studies and used in the rational design of new aromatase inhibitors [20–22].Despite clear advances in theAbbreviations:AG,aminoglutethimide;ESP,electrostatic surface potential;HBA,hydrogen bond acceptor;HOMO,highest occupied molecular orbital;HYD,hydrophobic group;LUMO,lowest unoccupied molecular orbital;NCI,National Cancer Institute;PSA,polar surface area;RMSD,root mean square deviation;VS,virtual screening.*Corresponding author.Tel.:þ390228500031;fax:þ390228901239.**Corresponding author.Tel.:þ351239488475;fax:þ351239488471.E-mail addresses:g.colombo@r.it (G.Colombo),samelo@ci.uc.pt(M.L.Sa´eMelo).Contents lists available at ScienceDirectEuropean Journal of Medicinal Chemistryjournal hom epage: /locate/ejmech0223-5234/$–see front matter Ó2009Elsevier Masson SAS.All rights reserved.doi:10.1016/j.ejmech.2009.05.003European Journal of Medicinal Chemistry 44(2009)4121–4127overall quality of aromatase homology models,their usefulness in ligand–protein high throughput docking experiments of large compound databases remains to be demonstrated.On the other hand,ligand-based pharmacophore models such as 3D-QSAR CoMFA developed for several classes of aromatase inhibitors,led to the design of very potent molecules [23–26],and a recent study by Langer and coworkers highlighted the value of pharmacophore models in virtual screening of large electronic compound databases,using a model derived from potent non-steroid aromatase inhibitors [27].In this work,we have summarized information about C6-substituted androstenedione derivatives,potent steroid aromatase2.Results and discussion 2.1.Pharmacophore modelingAndrostenedione derivatives are among the most potent steroid aromatase inhibitors found to date.In particular,it has been postulated that n -alkyl and n -phenyl aliphatic groups linked at position C6increase the anti-aromatase activity due to the pres-ence of a hydrophobic cavity at the enzyme binding site.In this sense,we have used a training set of potent C6-substituted androstenedione derivatives reported in the literature [7–10](Fig.1A),namely,6b -ethylandrosta-1,4-diene-3,17-dione (1),6-ethylandrosta-1,4,6-triene-3,17-dione (2),6-n -propylandrosta-1,4,6-triene-3,17-dione (3),6-benzylandrosta-4,6-diene-3,17-dione (4),6a -phenethylandrost-4-ene-3,17-dione (5)and 6-phenethy-landrosta-1,4,6-triene-3,17-dione (6),to derive a common-features pharmacophore model using the HipHop [28]algorithm of the Catalyst software [29].Brieﬂy,the program identiﬁes chemical features common to a training set of active compounds and generates hypotheses for their activity.These hypotheses are spatial dispositions of pharmacophoric points providing the compounds’relative alignment in the binding site of the enzyme.Each point accounts for an important chemical feature,such as hydrogen bond donors/acceptors,hydrophobic groups,negative/positive ionizable groups and aromatics.Due to the basic structures of the compounds used,hydrogen bond acceptors (HBA)and hydrophobic groups (HYD)were selected for the common-features alignment procedure.Besides its strong potency,this training set of molecules was chosen in order to account for the effect of different lengths,shapes and volumes of the hydrophobic moiety at C6,as well as its stereochemistry in relation to the steroid framework.Ten different pharmacophore hypotheses were automatically had only two acceptors and two hydrophobic groups.Visual inspection of the training set molecules aligned to the top ranked solution,STR-HYP (Fig.1B),revealed that the two hydrogen bond acceptors matched the 3-oxo (HBA1)and the 17-oxo (HBA2)groups.One of the hydrophobic groups,HYD1,superimposes the 19-methyl and the A–B ring junction,HYD2matches ring C and the 18-methyl,and the third apolar feature,HYD3,is related to the hydrophobic moiety linked at C6.Due to the rigid nature of the steroid scaffold,most of the common-features solutions were very similar to the top ranked pharmacophore model,with slight differences in the projection vectors of HBA1and HBA2(the loca-tion of hypothetical hydrogen bond donors)and the positioning of HYD3.The top ranked solution was therefore selected for the following steps.Fig.1.A)Training set of C6-substituted steroid aromatase inhibitors used for the common-features pharmacophore model generation [7–10].B)Common-features pharmacophore model of C6-substituted steroid aromatase inhibitors.The STR-HYP pharmacophoric query had ﬁve features:two hydrogen bond acceptors (HBA1and HBA2,green)and three hydrophobic groups (HYD1,HYD2and HYD3,cyan).The training set inhibitors (1,cyan,2,brown,3,yellow,4,blue,5,green,6,purple)are represented at the best ﬁt alignment to the model.(For interpretation of the references to colour in ﬁgure legends,the reader is refered to the web version of this article).Table 1Compound 5was converted into a shape query and combined with the initial hypothesis.The minimum similarity tolerance was set to 0.5.bFilters applied:Lipinski Rule of Five,rotatable bonds 8,PSA <150.M.A.C.Neves et al./European Journal of Medicinal Chemistry 44(2009)4121–41274122Cytochrome P450enzymes have an inner binding cavity accessible from the outside through one or more ligand channels [31].Therefore,in order to bind to the active site,aromatase inhibitors must have appropriate shape and volume.A set of inclusion volumes based on the shape of compound 5were applied to STR-HYP,and the steric tolerance was adjusted to allow good shape complementarity with the training set molecules.A new pharmacophore model combining pharmacophoric and shape features was obtained (STR-HYP þShape).2.2.Virtual screeningThe NCI open chemical repository collection is a large library of synthetic and natural compounds,with more than 260000different structures [32].This library has been used to screen,both in vitro and in vivo,for new anti-cancer and anti-viral agents,with the goal of identifying and evaluating novel chemical leads and their underlying biological mechanisms of action.The electronic version of the NCI repository (NCI database)was downloaded from the ZINC website [33]and converted into a multiconformer data-base using the catDB utility program of the Catalyst software [29].An initial virtual screening (VS)run with the STR-HYP pharma-cophore model identiﬁed 16212hits (5.6%of the database,Table 1),and the modiﬁed pharmacophore hypothesis,STR-HYP þShape,yielded 2189hits (0.8%of total number of compounds,Table 1).Most of the molecules excluded,based on shape features,areexpected to be false positives due to the presence of protruding groups that might clash with aromatase binding site residues.Furthermore,in order to increase the ‘‘drug-likeness’’of the new anti-aromatase candidates,several ﬁlters were applied,namely a Lipinski Rule of Five ﬁlter [34],and ﬁlters based on the maximum number of rotatable bonds (not more than 8)and polar surface area (PSA <150).This procedure reduced the number of compounds to 1462(0.5%of the database,Table 1).The molecules were then superimposed with the pharmacophore model and visually inspec-ted,19of them being selected based on a good root mean square deviation (RMSD)ﬁt to the model.Of these,10were available from the NCI database (Fig.2)and were obtained for experimental evaluation.Before performing the biochemical evaluation,the hits were inspected on a large electronic collection of organic chemistry (CrossFire Beilstein)using the MDL CrossFire Commander [35].Additional searches were performed using the PubChem Compound database [36],a publicly available resource with chemical and biological information of small molecules,including results from NCI anti-cancer drug screenings.It was found that none of them had been previously tested experimentally as aro-matase inhibitor.2.3.Biochemical evaluationThe compounds selected using our ligand-based VS strategy were biochemically evaluated for the ability to inhibit the enzyme aromatase.The molecules were initially screened at 10m M and 100m M concentrations,followed by a full concentration–response study,allowing the determination of the half-maximal inhibitory concentration (IC 50)reported in Table 2.Formestane and amino-glutethimide (AG),second and ﬁrst generation aromatase inhibi-tors,were also tested,in the same assay conditions,as reference compounds.Fig.2.NCI database hits selected based on the STR-HYP þShape pharmacophore model.Table 2Aromatase inhibition activity of NCI hits selected based on the STR-HYP þShape pharmacophore model.Aminoglutethimide and formestane were tested as refer-Results are shown as the mean ÆSEM of three independent experiments.b Inhibition at 30m M.cInhibition was not observed at concentrations 100m M.Table 3Enzyme kinetic parameters for compounds 8and 14,and type of aromatase inhi-Apparent inhibition constants (K i )were calculated by a nonlinear regression analysis using the Michaelis–Menten equation,and the type of inhibition was determined by a Lineweaver–Burk plot.bK I and k inact were obtained by a Kitz–Wilson plot.cInactivation was not observed at concentrations 2m M.M.A.C.Neves et al./European Journal of Medicinal Chemistry 44(2009)4121–41274123Most of the compounds selected showed anti-aromatase activity in the assay conditions used(Table2).Compounds7,13,15and16 are weak aromatase inhibitors with IC50higher than100m M. Compounds9(IC50¼9.8m M)and10(IC50¼15.5m M),have anti-aromatase potencies comparable to theﬁrst generation aromatase inhibitor tested,aminoglutethimide(IC50¼10.0m M),and,more interestingly,compounds8and14have an IC50in the nanomolar pound8(IC50¼0.274m M)is36times more active than aminoglutethimide,and compound14(IC50¼0.678m M)15times more potent than AG.However,these two molecules are less active than formestane(IC50¼0.092m M),the second generation aroma-tase inhibitor tested.Kinetic analysis of the enzyme activity was also performed.The kinetic constants,Michaelis–Menten constant(K m¼0.094m M)and maximum velocity of catalysis(V max¼163.7pmol of sub-strate minÀ1mgÀ1of protein)were calculated under initial velocity conditions.The type of inhibition was characterized using a Line-weaver–Burk plot.As expected,the most potent aromatase inhib-itors(compounds8,K i¼0.266m M,and14,K i¼0.385m M), inhibited the enzyme in a competitive manner(Table3).Compounds8and14were further tested for their ability to cause time-dependent inactivation of pound14, but not compound8,was able to inactivate the enzyme in the presence of NADPH,with a pseudoﬁrst order kinetics during theﬁrst12min of incubation(Fig.3).Kitz–Wilson analysis[37]of the results obtained,gave a k inact of0.608minÀ1and K I of21.4m M. Since the K i observed from the competition kinetics is lower than the K I obtained from the inactivation experiments,this suggests that the covalent binding of the inhibitor to the active site of the enzyme is the rate-limiting step of the inactivation.On the other hand,addition of substrate androstenedione in excess prevented inactivation(Fig.4A),as well as not including NADPH in the medium(Fig.4B).This suggests that the inhibitor acts at or near the active site of aromatase,and,since NADPH was essential for the time-dependent aromatase activity loss by compound14,that the inhibitor transformation into a reactive intermediate depends on enzyme catalysis.Furthermore,the nucleophilic trapping agent L-cysteine did not prevent enzyme inactivation to a signiﬁcant extent (Fig.4C),suggesting a covalent bond formation at the active site, between aromatase and the reactive electrophilic intermediate, therefore preventing diffusion of the activated inhibitor to the surrounding media.2.4.Stereoelectronic characterizationThe strong anti-aromatase activity of compound8,a B-nor steroid with similar hydrophobic core compared to the substrate androstenedione,prompted us to further evaluate the molecular geometry and electronic properties of these structures usinghigh Fig.4.Effect of androstenedione(A),NADPH(B)and L-cysteine(C)on the time-dependent inactivation of human placental aromatase by compound14.A)7.5m M of androste-nedione was incubated with(-)or without(:)7.5m M of inhibitor.Incubations of7.5m M of inhibitor without androstenedione(;)were also performed.B)7.5m M of inhibitor was incubated with(:)or without(-)NADPH.C)0.5mM of L-cysteine was incubated with(-)or without(:)7.5m M of inhibitor.Incubations of7.5m M of inhibitor without L-cysteine (;)were also performed.Each point represents the mean of three independent assays and the vertical bars,the standard error of themean.Fig.3.Time-and concentration-dependent inactivation of human placental aromataseby compound14in the presence of NADPH.The concentrations of inhibitor used were0m M(-),2.5m M(:),5m M(;)and7.5m M(A).A Kitz–Wilson plot of the same datais shown in the inset.Each point represents the mean of three independent assays andthe vertical bars,the standard error of the mean(SEM).M.A.C.Neves et al./European Journal of Medicinal Chemistry44(2009)4121–41274124level ab initio quantum chemistry methods.It was found that the geometries of androstenedione and its B-nor derivative are very superimposable,with an RMSD of 0.31Åbased on pairwise align-ment of the A,C and D ring carbons (Fig.5A).Furthermore,the distances between the hydrogen bond acceptor groups,an impor-tant pharmacophoric feature in our model,are very similar (10.44Åin androstenedione and 10.38Åin the B-nor derivative).Slight differences were however identiﬁed,namely the shape and size of the B ring,and the location of the acceptor linked to the ring A.The B ring of the nor-steroid,a cyclopentane,adopts an envelope conformation which is less bulky than the cyclohexane chair in androstenedione.The 3-oxo groups are located 0.63Åapart based on our superimposition.Electronic properties of the molecules were also calculated,namely the electrostatic surface potential (ESP)and the valence orbitals,i.e.the highest occupied molecular orbital (HOMO)and the lowest unoccupied molecular orbital (LUMO).These properties are similar in both compounds (Fig.5B).Negative potential was found in both carbonyls and along the O ]C3–C4]C5conjugation due to p electron delocalization.The HOMO and the LUMO are located at the A-ring,on the delocalized system.Therefore,both compounds are expected to share a similar aromatase recognition mechanism and reactivity.3.ConclusionsIn this paper we have built a new pharmacophore model for an important class of aromatase inhibitors and used it in a virtual screening study for new anti-aromatase hits.Previous knowledge on the binding determinants of C6-substituted androstenedione derivatives to the aromatase active site was essential to this ligand-based approach.A hydrophobic pocket close to the C6of steroid inhibitors was explored to improve the binding afﬁnity of the new anti-aromatase candidates.Therefore,the combination of essential pharmacophoric features with steric restrictions and ‘‘drug-like-ness’’ﬁlters allowed the isolation of a small subset,enriched in strong aromatase inhibitors,from the large NCI database.The screening methodology was validated experimentally by testing some of the most promising VS hits on an in vitro assay,and new potent aromatase inhibitors were found.6-Methyl-B-nor-androstenedione (8)was one of the most interesting compounds identiﬁed,with a low nanomolar IC 50and a competitive mechanism of inhibition.The strong anti-aromatase potency was rationalized based on structural and physicochemical similarities between the B-nor-androstenedione scaffold and the natural substrate of the enzyme.To the best of our knowledge,this is the ﬁrst report of B-nor-androgens as aromatase inhibitors.These compounds repre-sent an important new structural class of anti-aromatase agents and should be further pound 14was another interesting molecule identiﬁed,combining strong competitive inhibition properties with mechanism-based inactivation of the pounds 9and 10had anti-aromatase potencies comparable to aminoglutethimide.The value of experimentally validated virtual screening approa-ches of large compound databases relies on fast and affordable identiﬁcation of new hit compounds for particular targets of interest.However,hits identiﬁed with such approaches are usually non-opti-mized structures.Therefore,it is not surprising that the new aroma-tase inhibitors reported in this study are less potent than formestane.Nonetheless,starting with a training set of compounds from a single class,we were able to increase the chemical diversity of aromatase inhibitors,identifying interesting new scaffolds which can be further explored by lead optimization.In conclusion,we have described and validated a new ligand-based VS methodology for new aromatase inhibitors based on a pharmacophore model with common-features of steroid inhibi-tors.The screening of a large compound database was very fast and new potent and chemically diverse aromatase inhibitors couldbeFig.5.A)Superimposition of the minimized structures of androstenedione (grey)and B-nor-androstenedione (white)at the ab initio HF/6-31G **level.The molecules were superimposed based on RMSD of carbon atoms at the A,C and D rings,and represented on a side (right)and top view (left).B)Electrostatic surface potential (ESP),HOMO and LUMO valence orbitals derived for androstenedione (top)and B-nor-androstenedione (bottom).The ESP was mapped on the 0.02e/Å3electron density isocontour derived from ab initio HF/6-31G **calculations (V ¼0.1eV,blue;V ¼À0.1eV,red).The HOMO and LUMO are represented at an orbital amplitude of 0.1(blue)and À0.1(red).(For interpretation of the references to colour in ﬁgure legends,the reader is refered to the web version of this article).M.A.C.Neves et al./European Journal of Medicinal Chemistry 44(2009)4121–41274125identiﬁed.Moreover,this methodology has a broader application for a large variety of compound databases.putational and experimental methods4.1.Materials and general methodsThe NCI selected compounds were obtained from the Drug Synthesis and Chemistry Branch,Developmental Therapeutics Program,Division of Cancer Treatment and Diagnosis of the National Cancer Institute.DL-Aminoglutethimide,androstenedione,for-mestane and NADPH were purchased from Sigma–Aldrich(St.Louis, MO,U.S.A.).The[1b-3H]androstenedione(speciﬁc activity of25.3Ci/ mmol)and the liquid scintillation cocktail Optiphase Hisafe2were purchased from PerkinElmer(Boston,MA,U.S.A.).Radioactive samples were counted on a Packard Tri-Carb2900TR Liquid Scin-tillation Analyzer.All the other reagents were of adequate grade for biochemical analysis.4.2.Pharmacophore modelingPharmacophore design was performed using the Catalyst soft-ware[29].The aromatase inhibitors were initially submitted to the catDB utility program and a conformational search with internal energy minimization was performed using the best quality gener-ation type.A maximum of250conformers were saved within an energy window of20kcal/mol above the global minimum.The HipHop algorithm[28]of Catalyst was used for the common-cules(all but one feature was forced to map)and default settings were used for the other options.A similarity tolerance of0.5was used in the shape query.This value was chosen in order to match all training set molecules.4.3.Virtual screeningThe NCI database was downloaded from the2007release of the ZINC database[33]and converted into a multiconformer Catalyst database using the‘‘FAST’’conformational analysis model of the catDB utility program.A maximum of100conformations were generated and saved for each molecule.Pharmacophore searches were performed with‘‘fastﬂexible database search’’settings.Instant JChem[38]was used for management,search and prediction of molecular descriptors for the NCI hits.A Lipinski Rule of Five[34]ﬁlter was applied(molecular weight under500g/mol, not more than5hydrogen bond donors,not more than10hydrogen bond acceptors and calculated partition coefﬁcient,c log P,less than 5),as well as aﬁlter based on the maximum number of rotatable bonds(not more than8)and the maximum PSA(less than150).4.4.Human placental isolationHuman term placental microsomes were obtained by differen-tial centrifugation,according to the method described by Ryan[39], and were used as a source of aromatase.The microsomes were obtained by differential centrifugation and were resuspended in a buffer containing sodium phosphate(0.1M),sucrose(0.25M), glycerol(20%)and dithiothreitol(0.5mM),pH7.4,and stored in aliquots atÀ80 C until needed.Microsomal protein content was determined by the biuret method using bovine serum albumin as standard.4.5.Concentration–response and kinetic studiesAromatase activity was evaluated according to the method described by Siiteri and Thompson[40].The concentration–response and initial velocity experiments were performed as previously described[20,41].Brieﬂy,microsomal protein(30m g), [1b-3H]androstenedione(6.6Â105dpm)and NADPH(270m M) were used for the concentration–response experiment with an incubation time of20min.The molecules in study were initially tested at10m M and100m M concentrations,followed by a full concentration–response study with at least8concentrations ranging from0.01m M to160m M.For the initial velocity study the concentration of[1b-3H]androstenedione was varied from7.5to 100nM and the incubation time was set to5min.Three different concentrations of each inhibitor were tested.The tritiated water formed during the conversion of the tritiated substrate,[1b-3H] androstenedione,to estrone was quantiﬁed by liquid scintillation counting.Each assay was performed three times in duplicate and the results were treated by nonlinear regression analysis.4.6.Time-dependent inactivation assaySeveral concentrations of compounds8and14(up to ca.10times the IC50)were incubated at37 C in a medium containing sodium phosphate buffer(67mM),pH7.5,microsomal protein(300m g)and NADPH(900m M),in aﬁnal volume of500m L.Aliquots(50m L)were removed in duplicate at several times(0,4,8and12min),and immediately diluted in sodium phosphate buffer(67mM),pH7.5, [1b-3H]androstenedione(6.6Â105dpm)and NADPH(270m M)in aﬁnal volume of500m L.The mixture was then incubated at37 C for 20min,and the extent of the aromatization reaction was deter-mined by liquid scintillation counting as described previously.Each assay was performed three times.First order inactivation constants (k obs),at each inactivator concentration,were obtained from the slope of linear regressions of log aromatase activity remaining versus incubation time plots,multiplied by2.303.The K I and k inact were determined from the slope and y intercept of a Kitz–Wilson plot[37],respectively.Inactivation studies in the absence of NADPH were performed in the same manner,but NADPH was omitted in the initial incubation.For the same studies in the presence of andros-tenedione or L-cysteine,the substrate(7.5m M)or L-cysteine (0.5mM)was included in the initial incubation.4.7.Ab initio calculation detailsThe minimum energy conformations and electronic properties were determined by ab initio quantum chemistry calculations. Building blocks from the standard libraries of MAESTRO[42]were used to generate the initial geometry for the molecules in study, followed by a conformational search with the Systematic Unbounded Multiple Minimum(SUMM)[43]routine implemented in MACROMODEL v8.1[44],using the Merck Molecular Force Field (MMFF)[45]and the Generalized Born equation/Surface Area(GB/ SA)continuum solvation model[46]with parameters for water (dielectric constant3of78).The molecular mechanics geometries were further optimized with Gaussian98[47]using a split-valence basis set with polarization d-orbitals added to heavy atoms and polarization p-orbitals added to hydrogens(HF/6-31G**).The optimized geometries were used to calculate electronic properties,namely the total density,ESP,HOMO and LUMO. Contour surfaces were represented using Molden v4.6software [48].M.A.C.Neves et al./European Journal of Medicinal Chemistry44(2009)4121–4127 4126。

ECO作业训练教材

ECO作業訓練教材制作者陳祥琮完成日期﹕1998年8月28日檢查﹕核准﹕前言本訓練教材主要用于CC廠CAM人員初步訓練學習使用，緊緊圍繞CAM WORKSTATION這一整體按照實際作業流程分項介紹了從資料DOWN LOAD 、電子資料備份管理、各項程式作業到RESTORE 至工作站及PCB的EDIT 操作方法。

此外還結合現實CAM作業中的易出差錯處談到一些具體注意事項，以期望CAM人員引以為戒，減少作業漏失。

該教材適用範圍﹕負責接收管理CM電子資料、熟悉XPERT-1700CAM SYSTEM及CAM軟體操作之作業人員。

主要參考資料﹕【CAM DATABASE操作規範】、【治具課CAM制作檢查表作業規範】、【CAM底片制作作業規範】、【CAM EDIT PCB(PANEL)作規範】。

最後,希望本教材的建立能輔助CAM人員以規範為准逐步掌握CAM WORKSTATION這一塊實際作業方法，使得作業方式統一，確保品質，減少人為疏忽所造成之異常。

目錄前言 (1)第一節概論 (2)第二節ECO處理作業……………………………………………………5第三節ECO作業電腦操作指南…………………………………………10附件........................................................................................六．填寫plot傳票 (2)七．鑽孔及切型資料作業 (4)八．D/S資料作業…………………………………………………………………5九．底片edit 內容 (5)十．EDIT操作說明 (5)十一．CAM圖例解說 (6)。

宏观经济学习题及答案 (2)

4.
Which of the following will be counted as an expenditure in the measurement of GDP? (Assume that none of the transactions is concealed from the relevant authorities.) a. b. c. d. e. Purchase of flour by a bakery. Purchase of a loaf of bread using food stamps. Purchase of a lamp at a neighborhood garage sale. Payment by a parent to her child for doing household laundry. The value of a used automobile that remains unsold on the dealer's lot.
3.
If C is consumption, I is investment, G is government purchases and NX is net exports, according to the expenditure approach, Y would stand for ________; and the national income identity could be written as ________. a. b. c. d. e. CPI; Y = C + I + G + NX GDP; Y - C - I = G + NX transfers; Y = C + I + G – NX income; Y = C - I - G + NX the real interest rate; Y = C + I + G + NX

econ第一堂整合notes

不同時間上有不同我GAIN, 多變.e.g食左飯唔想再飲野
critical point, 最efficient, 最多utility, 要stop
競爭
lucky draw
一問一答
從中得到好處, 所以先買
demand curve always 向右下(always!), 價少多需求
D1, D2分別
價錢下降change in price, 同一條LINE shift, shift curft D2->D1, 有新PRODUCT出現/新聞話有毒乜乜
分配物品方法
first come first serve
困難: 起跑線不同, cost不同
compare就是經濟決定, 所以是經濟學家
拍賣
good view to 物品價值
食左21蚊, SATIFI左幾多?
預計下一次會lower satify, marginal=second utility bring to us
e.g anticiped demend reduce, demand will reduce S2 to S1
知market equilibrium ok,use for setting price.
識格價=經濟學家
最少價值得到最高利用,=經濟
all about money, 有D不能TRAN去MONEY, E.G AIR
D1 TO D2, 升DEMAND, E.g EVs
supply, cost again quanlity, P=cost, Q=Quantity
e.g 義工少人做, 有錢就多人做, 多SUPPLY
e.g 生產更多
e.g cost of EV reduc

Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings

Life-cycle carbon and cost analysis of energy efﬁciency measures in new commercial buildingsJoshua Kneifel *Ofﬁce of Applied Economics,Building and Fire Research Laboratory,National Institute of Standards and Technology,Gaithersburg,MD 20899,United States1.IntroductionBuilding energy efﬁciency has come to the forefront of political debates due to high energy prices and climate change concerns.Improving energy efﬁciency in new commercial buildings is one of the easiest and lowest cost options to decrease a building’s energy use,owner operating costs,and carbon footprint.This paper uses life-cycle costing and life-cycle assessment with extensive building cost databases,whole building energy simulations,state level emissions rates,and statewide average utility rates to determine the energy savings and cost-effectiveness of energy efﬁciency improvements,the resulting carbon emissions reduction,and the impact a cost on carbon would have on energy efﬁciency investment decisions.The results of this analysis show that conventional energy efﬁciency technologies such as thermal insulation,low-emissivity windows,window overhangs,and daylighting controls can be used to decrease energy use in new commercial buildings by 20–30%on average and up to over 40%for some building types and locations.Although increasing energy efﬁciency usually increases the ﬁrst costs of a building,the energy savings over the service life of the building often offset these initial higher costs.The ﬁrst costs can be lower for the more efﬁcient building design because,through integrated design,the improved efﬁciency reduces the size of the heating and/or cooling system required to meet the peak heating and/or cooling loads.The building type,local climate,and study period impact the ﬁnancial beneﬁts from energy efﬁciency improvements.The longer the study period,the greater the energy savings from energy efﬁciencies and the lower the life-cycle costs for more energy efﬁcient building designs.The local climate impacts the appro-priate integration of said improvements and the resulting savings from energy efﬁcient designs.Energy efﬁciency varies by building type because of inherent design differences (e.g.,number of stories,amount of glazing,and process loads).The cost-effective energy efﬁciency improvements not only save money,but also reduce a building’s carbon footprint.Carbon footprints are reduced by an average of 16%across all building types and sizes for a 10-year study period.These reductions are greater in buildings located in states that use large amounts of coal-ﬁred electricity because of the large amounts of carbonEnergy and Buildings 42(2010)333–340A R T I C L E I N F O Article history:Received 3August 2009Received in revised form 16September 2009Accepted 17September 2009Keywords:Carbon costEnergy efﬁciency Integrated design Life-cycle assessment Life-cycle costingA B S T R A C TEnergy efﬁciency in new building construction has become a key target to lower nation-wide energy use.The goals of this paper are to estimate life-cycle energy savings,carbon emission reduction,and cost-effectiveness of energy efﬁciency measures in new commercial buildings using an integrated design approach,and estimate the implications from a cost on energy-based carbon emissions.A total of 576energy simulations are run for 12prototypical buildings in 16cities,with 3building designs for each building-location combination.Simulated energy consumption and building cost databases are used to determine the life-cycle cost-effectiveness and carbon emissions of each design.The results show conventional energy efﬁciency technologies can be used to decrease energy use in new commercial buildings by 20–30%on average and up to over 40%for some building types and locations.These reductions can often be done at negative life-cycle costs because the improved efﬁciencies allow the installation of smaller,cheaper HVAC equipment.These improvements not only save money and energy,but reduce a building’s carbon footprint by 16%on average.A cost on carbon emissions from energy use increases the return on energy efﬁciency investments because energy is more expensive,making some cost-ineffective projects economically feasible.Published by Elsevier B.V.Abbreviations:AIRR,adjusted internal rate of return;ASHRAE,American Society of Heating,Refrigerating,and Air-Conditioning Engineers;BEES,building for environmental and economic sustainability;CBECS,commercial buildings energy consumption survey;EIA,U.S.Department of Energy’s Energy Information Administration;eGRID,U.S.Environmental Protection Agency’s 2007Emissions and Generation Integrated Database ;EPA,Environmental Protection Agency;HVAC,heating,ventilation,and air conditioning;LCC,life-cycle costing;LEC,low energy case;LEED,leadership in energy and environmental design;M,R,and R,maintenance,repair,and replacement;MARR,minimum average rate of return;NIST,National Institute of Standards and Technology;NREL,National Renewable Energy Laboratory;tCO 2e,ton of carbon dioxide equivalent.*Tel.:+13019756857;fax:+13019754032.E-mail address:joshua.kneifel@ .Contents lists available at ScienceDirectEnergy and Buildingsj o u r n a l ho m e p a g e :w w w.e l s e v i e r.c o m /l o ca t e /e nb u i l d0378-7788/$–see front matter.Published by Elsevier B.V.doi:10.1016/j.enbuild.2009.09.011dioxide emitted through coal combustion.A cost of carbon emissions is added to the building owner/operators energy costs based on the amount of energy use and type of fuel source.An additional cost on carbon increases the relative cost-effectiveness of energy efﬁciency improvements and potential carbon emissions reduction in new commercial buildings.Many energy efﬁciency measures are cost-effective without climate change policy,and should be implemented regardless of carbon restrictions.However, a cost on carbon results in a greater adjusted internal rate of return on energy efﬁciency investments,and makes energy efﬁciency projects more attractive relative to alternative investments.The change in cost-effectiveness is most prevalent in regions of the country that rely heavily on coal-ﬁred power generation.2.Literature reviewResearchers at the NREL have written several papers based on whole building energy simulations of energy efﬁcient building designs.Torcellini et al.[1]analyzes existing‘‘high-performance’’commercial buildings,andﬁnds that current technology can ‘‘substantially change how buildings perform’’by decreasing energy use by25–70%below code,which can be realized through a‘‘whole-building design approach.’’Grifﬁth et al.[3]develops a methodology for modeling commercial building energy perfor-mance by simulating the U.S.building stock,and determines that a set of building types and locations are required to effectively represent the building stock.Weather,building design,and energy loads lead to a large variation in total site energy use(less than 50kBtu/ft2yr to almost250kBtu/ft2yr).Grifﬁth et al.[4]simulates the potential for net zero energy commercial buildings in the U.S., and determines that with current technologies and design practices,62%of buildings and47%ofﬂoor space could reach net-zero energy use.Improving the building envelope,lighting controls,plug and process loads,and HVAC system to the best currently available technologies would decrease energy use43% below an ASHRAE90.1-2004compliant design.These studies are focused on energy use and energy consumption costs while ignoring life-cycle environmental and economic performance of the entire building.ASHRAE has recently introduced ASHRAE Advanced Energy Design Guides[2]for several building types,which give recom-mendations on how to build a minimum of30%better than ASHRAE 90.1-1999.The recommendations are based on the use of conventional technologies and design approaches,and vary by climate zone.There is no analysis regarding the cost-effectiveness of these recommendations or the resulting environmentalﬂows.The literature studies the costs of decreasing energy use in buildings,but focuses primarily on individual components instead of the entire building system.Cetiner and Ozkan[5]simulates different glass facade designs,andﬁnds that the most efﬁcient double facades are more energy efﬁcient but are not cost-competitive with the most efﬁcient single facade.Sekhar and Toon[6]ﬁnds double pane,low-e, reﬂective windows to be life-cycle cost-effective for a20-story building.Carter and Keeler[7]determines that green roofs increase total net present value costs by10–14%,and construction costs need to decrease by about20%before green roofs will become cost-effective with conventional roof designs.In the Praditsmanont and Chungpaibulpatana[8]case study,increased insulation thickness has a payback period of only three toﬁve years.Levinson and Akbari [9]simulates four buildings types for236cities across the U.S.,and determines that cool roofs save on average$0.356/m2of roof area annually across the U.S.The results vary by location,from$0.126/m2 to$1.14/m2.Consol[10]determines that designing commercial buildings to meet30%above current energy efﬁciency standards is not cost-effective.This study is of limited value because it only considers one prototypical building design.The results from the literature are mixed regarding the cost-effectiveness of increased energy efﬁciency in commercial building design.A possible reason for this may be that none of the literature incorporates an integrated design approach.The literature makes indirect links between energy use, environmental performance,and life-cycle cost through the analysis of LEED certiﬁed buildings.Newsham et al.[11] determines that,on average,LEED certiﬁed buildings save energy (18–39%)but with a large variation across individual buildings. Between28%and35%of LEED buildings actually use more energy per square foot than a comparable non-LEED building.The level of certiﬁcation is not an indicator of increased energy efﬁciency, which implies a disconnect between environmental performance and energy use.Paumgartten[12]ﬁnds that theﬁrst costs of constructing a building to obtain LEED certiﬁcation can easily be offset by the energy savings over a40-year study period,and lead to savings as high as250%of the up front costs.While the topics of energy use,environmental performance, life-cycle costs,and integrated design have each been studied,no study combines all aspects together to determine the simultaneous impacts of energy efﬁcient design on life-cycle costs,life-cycle carbon emissions,and energy use in an integrated building design context for commercial buildings across different climate zones.3.Study designTwelve building types are evaluated to consider a range of building sizes and energy intensities.For a prototypical building of each type,Table1shows the number ofﬂoors,size,and CBECS occupancy type,and includes the percentage of the U.S. commercial building stockﬂoor space accounted for by the building type[13].Table1shows the building types evaluated in this paper represent46%of the mercial building stockﬂoor space.A three-story and six-story dormitory,three-story and six-story apartment building,and15-story hotel represent the lodging category.An elementary school and high school represent education buildings.Three sizes of ofﬁce buildings(three-story, eight-story,and16-story)are used because ofﬁce buildings represent the largest building category,accounting for17%of U.S.building stockﬂoor space.A one-story retail store represents non-mall mercantile buildings while a one-story restaurant represents the food service industry.Building size ranges from 465m2to41806m2(5000–450000ft2).Life-cycle costing and life-cycle assessment are conducted over four different study period(i.e.,analysis period)lengths:one year, 10years,25years,and40years.A one-year study period length represents the time horizon of an investor who intends to turn over the property soon after it is built,such as a developer.The10-year, 25-year,and40-year study periods represent long-term owners at different ownership lengths.Longer study periods are more effective at capturing all relevant costs of owning and operating a building.However,longer study periods increase uncertainty in the precision of the life-cycle cost estimates because of the assumptions made about costs and occupant behavior decades into the future,such as future energy costs and energy consumption.For each building type,energy simulations are run for sixteen U.S.cities located in different ASHRAE90.1-2004sub-climate zones [14].1These cities are chosen as representative cities based on geographical location,population,and data availability.2Fig.1is a map of the ASHRAE90.1-2004climate zones.At least one city from 1Climate zones range from hot(1)to cold(8),and some have sub-zones:moist (A),dry(B),and marine(C).2Chosen cities are Amarillo,Texas,Anchorage,AK,Birmingham,AL,Honolulu,HI, Kansas City,MO,Los Angeles,CA,Miami,FL,Minneapolis Minnesota,New Orleans, LA,New York,NY,Phoenix,AZ,Pittsburgh,PA,Portland,ME,Salt Lake City,UT,San Francisco,CA,and Seattle,WA.J.Kneifel/Energy and Buildings42(2010)333–340 334each of the sub-climate zones,excluding Zone6B and Zone8,is included in the analysis.34.Cost data4.1.Building construction costsPrototypical building and component assembly costs originate from the RS Means CostWorks online database[15].The RS Means CostWorks Square Foot Estimator‘‘default costs’’for each building type,by component,are used to estimate the costs of a ‘‘prototypical building.’’4This prototypical building is used as a baseline to create a compliant building for each of the three energy efﬁciency design alternatives being considered in this analysis:designs to the ASHRAE90.1-2004and ASHRAE90.1-2007[16] energy efﬁciency standards,and a higher efﬁciency‘‘Low Energy Case’’(LEC)design.The RS Means CostWorks Cost Books are used to adapt the RS Means prototypical buildings to the three building designs.The components that are changed to meet ASHRAE90.1-2004and ASHRAE90.1-2007are insulation and windows.Insulation material and/or thickness in both the walls and roof decks are changed in order to meet the energy standards.The7.6cm(3in.)expanded polystyrene/perlite composite rigid insulation used as roof deck insulation in the prototypical buildings for ofﬁces,dormitories,and hotels is replaced with7.6–10.2cm(3–4in.)of extruded poly-styrene(EPS)rigid insulation depending on the ASHRAE standard and location.The polyisocyanurate roof deck insulation in the prototypical school buildings is increased from5.1cm(2in.)to 6.4cm to7.6cm(2.5–3in.)depending on the standard and location.Fiberglass blanket insulation(38.1cm(15in.)wide)is used in the wall cavities,with an R-value varying by location from 11.0to18.9.5If the blanket insulation cannot meet the requiredTable1Building characteristics of simulated building types.Building type Number ofﬂoors Floor height Building size Occupancy type U.S.ﬂoor spacem(ft)m2(ft2)(%)Dormitory3 3.66(12.0)2323(25000)Lodging7.1Dormitory6 3.66(12.0)7432(80000)Hotel15 3.05(10.0)41806(450000)Apartment3 3.05(10.0)2090(22500)Apartment6 3.15(10.3)5574(60000)School,Elementary1 4.57(15.0)4181(45000)Education13.8School,High2 4.57(15.0)12077(130000)Ofﬁce3 3.66(12.0)1858(20000)Ofﬁce17.0Ofﬁce8 3.66(12.0)7432(80000)Ofﬁce16 3.05(10.0)24155(260000)Retail store1 4.27(14.0)743(8000)Mercantile a 6.0 Restaurant1 3.66(12.0)465(5000)Food service 2.3a Only includes non-mallﬂoorarea.Fig.1.ASHRAE90.1-2004climate zones with cities from the analysis(not shown:Honolulu,HI in Zone1;Anchorage,AK in Zone7).3Climate Zone6B and Zone8have a small portion of the total building stock dueto the relatively sparse population distribution.The mountain west census divisionaccounts for6.5%of mercial buildings and6%of mercialﬂoorspace.The only Zone8area in the United States is located in northeastern Alaska.4Disclaimer:Certain trade names and company products are mentionedthroughout the text.In no case does such identiﬁcation imply recommendationor endorsement by the National Institute of Standards and Technology,nor does it imply that the product is the best available for the purpose.5The smallest insulation value is R-11because it is the lowest R-value available for blanket insulation.J.Kneifel/Energy and Buildings42(2010)333–340335R-value,then1.3cm(0.50in.)or1.9cm(0.75in.)polyisocyanurate rigid insulation is placed on the wall exterior.Windows are altered in three ways:number of panes,low-emissivity(low-e)coatings,and solar heat gain controlﬁlms.There areﬁve different combinations of these three characteristics used in the cost estimates:(1)single pane,(2)single pane with solar heat gain control,(3)double pane,(4)double pane with solar heat gain control,and(5)double pane with solar heat gain control and a low-e coating.Some prototypical buildings have single pane windows that must be replaced by double pane windows.Double pane windows’cost data are available from the RS Means database. Low-e coatings are assumed to add an extra15%to the window material costs while solar heat gain controlﬁlms add an extra10% to window material costs.6The LEC design increases the thermal efﬁciency of insulation and windows while introducing daylighting and window over-hangs.The new insulation requirements go beyond ASHRAE90.1-2007by adding at least1.3cm(0.5in.)of polyisocyanurate rigid insulation to the wall exterior for all climate zones.Rigid insulation is added because the blanket insulation alreadyﬁlls the8.9cm (3.5in.)wall cavity.Roof deck insulation is increased for all climate zones by at least an R-5continuous insulation(ci)value,for a total of R-20ci to R-35ci.The LEC requires schools to use7.6–12.7cm (3–5in.)of polyisocyanurate rigid insulation and all other building types to use7.6–17.8cm(3–7in.)of EPS rigid insulation.The LEC also adds daylighting controls and overhangs for window shading based on the EnergyPlus‘‘Example File Generator’’recommenda-tions[17].Daylighting is included for all building types at a cost of $28.17/m2($2.62/ft2).7Overhangs are priced at$133.01/m2 ($12.37/ft2),and are used in all but the coldest climate zones.8 The three designs alter the heating and cooling loads of the building,which leads to a change in the appropriate size of the HVAC system.Whole building energy simulations,which will be discussed in the next section,‘‘autosize’’the HVAC system to determine the smallest system that will still meet the ventilation load requirements.Smaller HVAC systems cost less to purchase and install,which can offset some or all of the additional costs from other measures to increase the building’s energy efﬁciency.Based on the costs of the system used in the prototypical building,the HVAC costs are increased or decreased to the appropriate size speciﬁed in the energy simulations based on a linear interpolation of costs.Construction costs for each building in each location are determined by summing the baseline costs for the prototypical building and the changes in costs required to meet the alternative designs.National average construction costs are adjusted with the 2008RS Means CostWorks City Indexes to control for local price variations.The‘‘weighted average’’city construction cost index is used to adjust the costs for the baseline prototypical building while ‘‘component’’city indexes are used to adjust the costs for the design changes.9The city-indexed construction costs do not account for contractor and architect fees.Once the indexed construction costs of the building have been calculated,it is multiplied by the contractor‘‘mark-up’’rate.The result is then multiplied by the architectural fees rate.10The result is the‘‘ﬁrst costs.’’4.2.Maintenance,repair,and replacement costsComponent and building lifetimes and component repair requirements are collected from Towers et al.[19].Building service lifetimes are assumed constant across climate zones: apartments last for65years;dormitories for44years;hotels, schools and ofﬁce buildings for41years;retail stores for38years; and restaurants for27years.Insulation and windows are assumed to have a50-year lifespan.Insulation is assumed to have no maintenance and repair requirements while windows have an annual repair rate of1%of window panes.The heating and cooling units have different lifespans and repair rates based on climate. Cooling units have short lifespans and repair frequencies in hot climates(13years for replacement and9years for repairs in Miami)and long ones in cold climates(50years for replacement and33years for repairs in Anchorage).The opposite is true of heating units with a lifespan of18years and repairs every4years in Anchorage and50years for replacement and19years for repairs in Miami.Future costs are collected from two sources.The baseline average maintenance,repair,and replacement(M,R,and R)costs (excluding HVAC)per square foot for each building type,by year of service life,are from Towers et al.[19].RS Means CostWorks is the source of M,R,and R costs for the components that change across building designs.In this analysis,only HVAC system components are replaced over the maximum40-year study period.Windows have an assumed annual repair cost equal to replacing1%of all window panes.4.3.Energy costsUtility rates for electricity and natural gas are obtained from the EIA.The state-wide average retail price per3.6MJ(1kWh)of electricity is used as the building owner’s/operator’s cost of electricity consumption.The EIA December2008Natural Gas Monthly[20]is used to obtain the average retail natural gas prices by state for2007.Whole building energy simulations for the192 building type-location combinations are run in EnergyPlus 3.0 through its‘‘Example File Generator’’to obtain each buildings annual energy use for electricity and natural gas.The annual energy use for each fuel type is multiplied by the average fuel cost for the building location to obtain a building’s annual energy costs. It is assumed that the building maintains its energy efﬁciency performance throughout the study period.114.4.Building residual valueThe building residual value–its value at the end of the study period–is estimated based onﬁrst costs and remaining component and building lifetimes.The baseline residual value is theﬁrst cost(minus any components replaced over the time period)multiplied by the ratio of the remaining life of the building to the service life of the building.The remaining residual value stems from the only component replaced over the study period,the HVAC equipment.The HVAC system components have different remaining lives–and thus residual values–than the building as a whole.Any remaining years in the lifetime of the HVAC equipment is used to estimate a residual value by taking the initial cost of the HVAC system and multiplying it by the ratio of remaining life to service life of the equipment.6The low-e and solar heat gain controlﬁlm cost estimates are from the RS Means database.7Cost of10ﬁxtures per92.9m2(1000ft2)[15].8Cost data obtained from Winiarski et al.[18].9Component indexes used in the analysis are‘‘thermal and moisture protection,’’‘‘openings,’’‘‘ﬁre suppression,plumbing,and HVAC,’’and‘‘electrical,communica-tions,and utilities.’’10The contractor fee and architectural fee rates are the default rates provided by RS Means at25%and7%,respectively.11The assumption of constant efﬁciency performance is made because it is unclear how building energy efﬁciency will deteriorate over time.Controlling for building temporal energy efﬁciency deterioration is beyond the scope of this paper, but is an excellent topic for future research.J.Kneifel/Energy and Buildings42(2010)333–340 3365.Life-cycle cost analysisLife-cycle costing(LCC)estimates the net present value of all relevant costs throughout the study period,including construction costs,maintenance,repair,and replacement costs,energy costs, and residual values.12LCC of buildings compares the costs from a ‘‘base case’’building design costs from alternative building designs.LCC is generally used to determine if future operational savings justify higher initial investments.Since the ASHRAE90.1-2004 design is compliant with the oldest energy standard studied,it is expected to lead to the lowestﬁrst costs and least energy efﬁcient building.Both the ASHRAE90.1-2007design and the LEC design are compared to the ASHRAE90.1-2004design–the‘‘base case’’–todetermine the LCC,carbon emissions,and carbon cost savings for each alternative.This study analyzes LCC results via two measures: net savings as a percentage of base case LCC and the adjusted internal rate of savings is the difference between the base case and alternative design’s LCCs.The adjusted internal rate of return(AIRR)is the annualized return on the energy efﬁciency investment costs.13The AIRR of building energy efﬁciency investments can be compared to an investor’s minimum accep-table rate of return(MARR),such as gains from competing investments in the stock or bond market over the same study period or,in the case of the federal government,the savings in interest payments from decreasing the national debt.If the AIRR is greater than the investor’s MARR,the energy efﬁciency investment is preferred.All future costs,including M,R,and R costs,energy costs,and residual values,are discounted to their equivalent present values based on the relevant discount factors[22].All costs and values are discounted based on the DOE real discount rate for energy conservation projects,3.0%in2008.EIA energy price forecasts are embodied in the discounting of electricity and natural gas costs over the study period.NIST’s BEES software[23]is used to compute the life-cycle costs for the building design alternatives in compliance with ASTM Standards of Building Economics[24]. 6.Environmental life-cycle assessmentThe environmentalﬂows from operational energy use are derived from two sources.The state-level average emissions per 3.414MBtu/h(1MW)of electricity for carbon dioxide(CO2),sulfur dioxide(SO2),and nitrogen oxides(NO x)are obtained from eGRID 2007[25].eGRID integrates data from three sources:emissions data from the EPA,generation data and fuel mixes from the EIA, and electric generating company data from the Federal Energy Regulatory Commission.Electricity emissions data(excluding CO2, SO2,and NO x)and natural gas emissions data are collected from BEES4.0.Life-cycle environmentalﬂows from building construction, repair,and replacement are derived from U.S.Environmental Input–Output Tables included in the SimaPro7software[26]that have been adapted to the NIST BEES life-cycle assessment framework.The adapted Environmental Input–Output Tables quantify resource inputs and pollutantﬂows for172substances based on national averageﬂows per dollar spent in the U.S. construction industry’s commercial and institutional building sector.The BEES software is used to assess the life-cycle energy and materialﬂow from construction and operation of the building and estimate its carbon footprint.Life-cycle carbon emissions(includ-ing all greenhouse gas emissions)are highlighted in this paper to allow for a direct comparison across building types,designs,and locations.Carbon emissions from operational energy use are reported separately to study how a cost on carbon impacts a building’s life-cycle costs.7.ResultsTwelve building types,representing a range of building sizes and energy intensities,are evaluated over four study period lengths for three alternative building designs.For each building type,energy simulations are run for sixteen U.S.cities located across different sub-climate zones.The resulting energy use and energy costs,life-cycle costs,carbon emissions,and carbon cost implications are discussed below.7.1.Energy use and costsASHRAE90.1-2004compliance is expected to lead to the least efﬁcient design because newer standards are expected to lead to higher energy efﬁciency.However,the change in total operational energy use for the ASHRAE90.1-2007design relative to the base case ASHRAE90.1-2004design for all building types range from an increase of11.5%to a decrease of23.8%with a mean decrease of only3.2%for a one-year study period.Fig.2shows that not only are most reductions relatively small,the use of ASHRAE90.1-2007over ASHRAE90.1-2004does not necessarily lead to energy use reductions due to minor relaxation of glazing performance requirements for some climate zones.14As is expected,increasing the energy efﬁciency of a building beyond the ASHRAE standard requirements decreases annual energy use.Fig.2shows the LEC leads to reductions of3.2–44.2% relative to the base case ASHRAE90.1-2004design for a one-year study period.15Nine of the twelve building types have an energy savings greater than20%for all locations while eight of the twelve have at least one location that has a30%or greater energy reduction.Five building types have average energy reductions over 30%.A30%reduction in energy use for most building types relative to ASHRAE90.1-2004appears to be achievable and reasonably straightforward to reach through conventional building technol-ogies.Energy cost savings are not perfectly correlated with energy use reductions due to differences in the marginal costs of electricity and natural gas across states,region-speciﬁc EIA price projections, and building process loads.The smallest savings in energy and energy costs occurs in colder cities,Anchorage and Minneapolis, while the greatest savings occurs in cities located inmore Fig.2.Annual energy use savings relative to ASHRAE90.1-2004compliant design,by building type.12Fuller and Petersen[21].13The AIRR is preferred over the IRR because it adjusts the rate of return for reinvestment of interim receipts.14Eachﬁgure plot the range between the maximum and minimum values by building type.15These magnitudes are less than the HVAC energy savings because energy from user demands such as process loads are assumed to be constant across the alternatives.J.Kneifel/Energy and Buildings42(2010)333–340337。

宏观经济学习题及答案 (4)

Multiple Choice Questions1.To analyze aggregate productivity, economists typically assume:a.That the hours each person works varies with the wage rate.b.That all of the capital and labor in the economy are fully utilized.c.That output can increase only if inputs have become more productive.d.All of the above.e.None of the above.2.The output an economy can produce with one unit of capital and one unit of labor is:monly referred to as labor productivity.b.Indicated by the A variable in the production function.c. A variable that depends on how many units of capital and labor are available.d.All of the above.e.None of the above.3.Which of the following is true about total factor productivity (TFP)?a.It can be measured just like capital and labor.b.It cannot be directly measured so it has to be calculated from given values of capital, labor andoutput.c.While it cannot be measured directly, it has an exponent of 0.3 in the Cobb-Douglas productionfunction.d.While it cannot be measured directly, it has an exponent of 0.7 in the Cobb-Douglas productionfunction.e.None of the above.4.Suppose than an economy has the production function Y = AK0.3L0.7 where Y equals $12 trillion, capital K is$27 trillion, and labor L is 64 million workers. Given this information, what is the closest approximation of total factor productivity A?a.less than 0.01b.around 0.25c.roughly 0.33d.close to 0.4e.exactly 1445.What do you think would be the production function’s single best prescription for low-income countries tocatch up with to high-income countries?a.To increase their labor force.b.To ask help of the rich countries.c.To increase their stock of capital.d.To find more efficient ways to allocate and use capital and labor.e.None of the above.6. A ten percent increase in total factor productivity will increase:a.Economic output by ten percent.b.The marginal product of labor (MPL) by ten percent.c.The marginal product of capital (MPK) by ten percent.d.All of the above.e.None of the above.7.The marginal product of labor indicates ________. Therefore the MPL curve is also ________.a.The quantity of labor supplied for a given wage; the supply curve of labor.b.The quantity of labor demanded for a given wage; the demand curve of labor.c.The quantity of labor supplied for a given wage; the equilibrium price of labor.d.The quantity of labor demanded for a given wage; the equilibrium price of labor.e.None of the above.8.Equilibrium market prices for capital and labor are $10 and $8, respectively. Then, the economy experiencesone or more supply shocks, so that the marginal product of capital is $12, and the marginal product of labor is $9. Assuming that the available quantities of capital and labor are fixed, which of the following is (are) likely to decrease as the economy approaches its new equilibrium?a.Economic profits.b.Total economic output.c.Real rental price of capital.d.The quantity of capital in use.e.None of the above.Discussion Questions1.What relationship does the aggregate production function portray? Which of the production function’s variablesare endogenous and which are exogenous?The aggregate production function represents the relationship between the quantities of inputs that go into the production process and the output that is produced with those inputs.In the production function Y = F(K,L), output (Y) is an endogenous variable whose value is explained by the production function while the capital (K) and labor (L) inputs used in production are the exogenous variables that determine or explain the level of output produced.2.Explain how an equilibrium factor price is established in a factor market if there is either an excess demand forthe factor or an excess supply of the factor.Equilibrium occurs in a factor market when the quantity of the factor demanded by firms equals the quantity of the factor its owners offer for sale. The factor price at which this condition is met is the equilibrium price of the factor. When there is an excess demand, firms want to hire more of the factor than owners of the factor offer for sale. This occurs when the factor’s price is below the equilibrium price. Firms’ competition for the factor drives up its price, which eliminates the excess demand. If the price of the factor is above the equilibrium price, the quantity of a factor demanded is less than the quantity offered for sale and there is an excess supply of the factor. In this case, factor owners compete against one another and drive the factor price down. So excess demand and excess supply in a factor market cause the factor’s price to move toward its equilibrium value.3.What determines the distribution of national income between payments to labor and payments to capital?Assuming that labor and capital inputs are hired in perfectly competitive factor markets, national income is divided between labor and capital with the payments to each input determined by the input’s marginal product. Support for the Cobb-Douglas production function comes from evidence that the shares of national income going to labor and capital remain constant over time, as it predicts, regardless of the level of national income.4.Suppose an economy has total income of $8 trillion, where total labor income equals $6 trillion and capitalincome equals $2 trillion. Which are the values of the exponents on labor and capital using a Cobb-Douglas production function?A Cobb-Douglas production function uses the labor income and capital income shares of total income asthe exponents on labor and capital respectively. In this case, the labor income share is 0.75, and the capital income share is 0.25. This economy could be represented by the following production function:Y = F(K, L) = AK0.25L0.75Analytical QuestionsThese questions should be answered based on the standard models of analysis developed in class.The information in the various parts of the question is sequential and cumulative.b.In Year 1, the economy suffered a technological breakdown. However, because of widespread laborcontracts, there was no change in the real wage. Incorporating only this new information, clearly and accurately show in your diagrams above what effects this would have on (1) actual economic output,(2) employment, and (3) the real wage. These effects should be drawn in RED.c.Provide an economic explanation of what you have shown in your diagrams above. Discuss whathappens to (1) actual economic output, (2) employment, and (3) the real wage. Be sure to explain why these effects take place.In Year 1, because of the technological breakdown, economic output declined for any given levels of labor and capital. This implies that total factor productivity had declined. This is represented by a downward rotation of the production function from Y = A0*F(K0, L) to Y = A1*F(K0, L).The downward rotation of the production function causes the marginal product of labor to decline for any given level of employment. This reduces the demand for labor and is represented by a leftward shift of the demand for labor curve from D L0 to D L1.At the initial equilibrium wage rate, w0, the quantity of labor supplied is greater than the quantity of labor demanded so that the labor market is now in disequilibrium. Because there was no change in the real wage, i.e., w1 = w0, employment falls from L0 to L1 where the marginal product of labor is equal to the real wage. With employment now at L1, economic output declines from Y0 to Y1 along the new, lower production function Y = A1*F(K0, L).Actual economic output has declined from Y0 to Y1; employment has fallen from L0 to L1; but the real wage has not changed so that w1 = w0.d.In Year 2, there was a permanent decline in the labor force participation rate and the real wage adjustedto return the labor market to equilibrium. Incorporating only this new information, clearly and accurately show in your diagrams above what effects this would have on (1) actual economic output,(2) potential economic output, (3) employment, and (4) the real wage. These effects should be drawnin BLUE.e.Provide an economic explanation of what you have shown in your diagrams above. Discuss whathappens to (1) actual economic output, (2) potential economic output, (3) employment, and (4) the real wage. Be sure to explain why these effects take place.In Year 2, the permanent decline in the labor force participation rate reduces the size of the labor force for any given real wage. This is represented by a leftward shift of the supply of labor curve from L S0 to L S2.At the Year 1 real wage of w1, the quantity of labor supplied is greater than the quantity of labor demanded. Consequently, when the labor market returns to equilibrium, the real wage has declined from w0 = w1 to w2 and equilibrium employment has increased from L1 to L2.With equilibrium employment now at L2, economic output increase from Y1 to Y2 along the new, lower production function, Y = A1*F(K0, L). Because the labor market is in equilibrium, this level of economic output is also the economy’s new potential output level, i.e., Y2 = Y P2.Actual economic output has increased from Y1 to Y2 but has declined from Y0; potential economic output has declined from Y P0 to Y P2; employment has increased from L1 to L2 but has declined from L0; and the real wage has declined from w1 = w0 to w2.Econ 100B / UGBA 101B: Macroeconomic AnalysisPost Lecture #4 ExercisesAggregate Production and Productivityc.Suppose that there is a significant increase (relative to the growth in the labor force) in the number ofworkers who are retiring. Incorporating only this additional information, clearly and accurately showin your diagrams above what effects this would have on equilibrium (1) economic output, (2)employment, (3) the real wage rate, (4) the capital stock, and (5) the real rental cost of capital. Theseeffects should be drawn in RED.d.Provide an economic explanation of what you have shown in your diagrams above. Discuss whathappens to equilibrium (1) economic output, (2) employment, (3) the real wage rate, (4) the capitalstock, and (5) the real rental cost of capital. Be sure to explain why these changes take place.In the labor market, the significant increase in the number of workers who are retiring relativeto the growth in the labor force reduces the labor force participation rate. This causes the supplyof labor to decline at any real wage rate. This is represented by a leftward shift of the laborsupply curve from L S0 to L S1.At the initial real wage of w0 there is now an excess demand for labor. In order to re-establishequilibrium in the labor market the real wage must increase from w0 to w1. Equilibrium in thelabor market is then established with the equilibrium real wage rising from w0 to w1 but withequilibrium employment falling from L0 to L1.The decline in equilibrium employment from L0 to L1 causes a decline in equilibrium economicoutput along the production function Y = A0*F(K0, L) from Y0 to Y1.In the capital market, the decline in equilibrium employment reduces economic output for anygiven level of total factor productivity and the capital stock. This is represented by a downwardrotation of the production function from Y = A0*F(K, L0) to Y = A0*F(K, L1) where L1 < L0. Thisresults in equilibrium economic output falling from Y0 to Y1. (This decline in economic output isidentical to the decline described above for the labor market).As a result of this downward rotation of the production function, the slope of the productionfunction decreases, leading to a decline in the marginal product of capital. A decline in themarginal product of capital is also a decline in the demand for capital at any given real rentalcost of capital. This is represented by a downward (or leftward) shift (or rotation) of the capitaldemand curve from K D0 to K D1.At the initial real rental cost of capital of r c0 there is now an excess supply of capital. In order tore-establish equilibrium in the capital market the real rental cost of capital must decline from r c0to r c1. Equilibrium in the capital market is then established with the equilibrium real rental costof capital falling from r c0 to r c1 but with no change in the equilibrium capital stock because thecapital stock is fixed, i.e., K1 = K0.In the final equilibrium, (1) economic output declines from Y0 to Y1, (2) employment declinesfrom L0 to L1, (3) the real wage increases from w0 to w1, (4) the capital stock does not change, i.e.,K1 = K0, and (5) the real rental cost of capital declines from r c0 to r c1.e.In addition, suppose that the retiring workers possessed higher than average work skills. Incorporatingonly this additional information, clearly and accurately show in your diagrams above what effects this would have on equilibrium (1) economic output, (2) employment, (3) the real wage rate, (4) the capital stock, and (5) the real rental cost of capital. These effects should be drawn in BLUE.f.Provide an economic explanation of what you have shown in your diagrams above. Discuss whathappens to equilibrium (1) economic output, (2) employment, (3) the real wage rate, (4) the capital stock, and (5) the real rental cost of capital. Be sure to explain why these changes take place.In the labor market, because the retiring workers possessed higher than average work skills, their departure from the labor market reduces the average level of work skills, reducing total factor productivity and economic output for any given level of employment and the capital stock.This is represented by a downward rotation of the production function from Y = A0*F(K0, L) to Y = A2*F(K0, L).As a result of this downward rotation of the production function, the slope of the production function decreases, leading to a decline in the marginal product of labor. A decline in the marginal product of labor is also a decrease in the demand for labor at any given real wage rate.This is represented by a downward (or leftward) shift (or rotation) of the demand for labor curve from L D0 to L D2.At the real wage of w1 there is now an excess supply of labor. In order to re-establish equilibrium in the labor market the real wage must decline from w1 to w2. (Depending on the magnitude of the shift in the demand for labor function, w2 could be below w0.) Equilibrium in the labor market is then established with the equilibrium real wage falling from w1 to w2 and with equilibrium employment falling from L1 to L2.The decline in equilibrium employment from L1 to L2 causes a decline in equilibrium economic output along the production function Y = A2*F(K0, L) from Y1 to Y2.In the capital market, the decline in total factor productivity reduces economic output for any given level of the capital stock and employment. This is represented by a downward rotation of the production function from Y = A0*F(K, L1) to Y = A2a*F(K, L1).As a result of this downward rotation of the production function, the slope of the production function is reduced, leading to a decrease in the marginal product of capital. A decrease in the marginal product of capital is also a decline in the demand for capital at any given real rental cost of capital. This is represented by a downward (or leftward) shift (or rotation) of the demand for capital curve from K D1 to K D2a.At the real rental cost of capital of r c1 there is now an excess supply of capital. In order to re-establish equilibrium in the capital market the real rental cost of capital must decline from r c1 to r c2a. Equilibrium in the capital market is then established with the equilibrium real rental cost of capital falling from r c1 to r c2a but with no change in the equilibrium capital stock because the capital stock is fixed, i.e., K2a = K1 = K0.Although the stock of capital has not changed, the decline in total factor productivity reduces economic output from Y1 to Y2a.In addition, equilibrium employment has declined from L1 to L2. For any given level of total factor productivity and the capital stock, a decline in employment reduces economic output. This is represented by a downward rotation of the production function from Y = A2*F(K, L1) to Y = A2*F(K, L2).As a result of this downward rotation of the production function, the slope of the production function is reduced, leading to a decrease in the marginal product of capital. A decrease in the marginal product of capital is also a decline in the demand for capital at any given real rental cost of capital. This is represented by a downward (or leftward) shift (or rotation) of the demand for capital curve from K D2a to K D2.At the real rental cost of capital of r c2a there is now an excess supply of capital. In order to re-establish equilibrium in the capital market the real rental cost of capital must decline from r c2a to r c2. Equilibrium in the capital market is then established with the equilibrium real rental cost of capital falling from r c2a to r c2 but with no change in the equilibrium capital stock because the capital stock is fixed, i.e., K2 = K2a = K1 = K0.Although the stock of capital has not changed, the decline in equilibrium employment reduces economic output from Y2a to Y2.In the final equilibrium, (1) economic output declines from Y1 to Y2, (2) employment declines from L1 to L2, (3) the real wage declines from w1 to w2, (4) the capital stock does not change, i.e., K2 = K1 = K0, and (5) the real rental cost of capital declines from r c1 to r c2.。

新理念大学英语网络教学系统

新理念大学英语网络教学系统各位同学：请先下载新理念学习大厅，下载地址，然后按照下面的方法配制：珠海校区用户请在初次安装后，打开“开始”菜单，依次打开“程序”→“新理念大学英语2006版”→“新理念大学英语学习大厅配置程序”→将服务器地址替换为http://202.116.65.96/，点保存东校区用户请在初次安装后，打开“开始”菜单，依次打开“程序”→“新理念大学英语2006版”→“新理念大学英语学习大厅配置程序”→将服务器地址替换为http://202.116.65.95/，点保存下载学习大厅并配置完毕后,请用自己的学号进入即可学习,初始密码为11111111,进入后及时修改密码!如果出现安装错误或者使用时无法单元测试的问题请参阅：解决方案新用户请下载使用指南学生手册教师手册如果在使用过程中有任何疑问，欢迎在此留言!也可以发邮件:珠海校区用户请发至：cezh@东校区用户请发至：cegz@ 或mlb@ VISTA用户请注意：学习大厅必需按照下列要求配置后才能正常运行，请按照下列方法操作：第一步：右击程序（学习大厅的快捷方式），在弹出菜单中依次点击属性→兼容性→把“用兼容性模式运行这个程序”打勾（√）→选择相应的系统版本，如XP （SP2）→然后确定，运行程序。

如果还是不行的话，那么重复上面的，同时把用“请以管理员身份运行这个程序”打勾（√），如果系统提示您输入管理员密码或进行确认，请键入密码或单击“继续”，然后确定。

第二步：打开“开始”菜单，依次打开“程序”→“新理念大学英语2006版”，然后右击“新理念大学英语学习大厅配置程序”，在弹出菜单中依次点击属性→兼容性→把“用兼容性模式运行这个程序”打勾（√）→ 选择相应的系统版本，如XP（SP2）→然后确定，运行程序。

如果还是不行的话，那么重复上面的，同时把用“请以管理员身份运行这个程序”打勾（√），如果系统提示您输入管理员密码或进行确认，请键入密码或单击“继续”，然后确定，运行程序。

曼昆宏观经济学教案Ecn101_lecture14

CHAPTER 4Money and Inflationslide 1From last time …CHAPTER 4Money and Inflationslide 2The downward -sloping AD curveAn increase in the price level causes a fall in real money balances (M /P ),causing adecrease in the demand for goods & services.Y P ADCHAPTER 4Money and Inflationslide 3Shifting the AD curveAn increase in the money supply shifts the AD curve to the right.YPAD 1AD 2CHAPTER 4Money and Inflationslide 4The long -run aggregate supply curveYPLRASYThe LRAS curve is vertical at the full-employment level of output.CHAPTER 4Money and Inflationslide 5Long -run effects of an increase in MYPAD 1AD 2LRASYAn increase in M shifts the AD curve to the right.P 1P 2In the long run, this increases the price level……but leaves output the same.CHAPTER 4Money and Inflationslide 6The short run aggregate supply curveYPPSRASThe SRAS curve is horizontal:The price level is fixed at a predetermined level, and firms sell as much as buyers demand.CHAPTER 4Money and Inflationslide 7Short -run effects of an increase in MYPAD 1AD 2…an increase in aggregate demand…In the short run when prices are sticky,……causes output to rise.PSRAS Y 2Y 1CHAPTER 4Money and Inflationslide 8The SR & LR effects of ∆M > 0YPAD 1AD 2LRASYPSRAS P 2Y 2A = initialequilibrium ABCB = new short-run eq’m after Fed increases MC = long-runequilibriumCHAPTER 4Money and Inflationslide 9Continuing from where we ended lasttime …CHAPTER 9Introduction to Economic Fluctuationsslide 10Shocksshocks : exogenous changes in aggregatesupply or demandShocks temporarily push the economy awayfrom full-employment.An example of a demand shock:exogenous decrease in velocityIf the money supply is held constant, then a decrease in V means people will be using theirmoney in fewer transactions, causing a decrease in demand for goods and services:CHAPTER 9Introduction to Economic Fluctuationsslide 11LRASAD 2PSRAS The effects of a negative demand shockYPAD 1YP 2Y 2The shock shifts AD left, causing output andemployment to fall in the short run A B COver time, prices fall and theeconomy moves down its demand curve toward full-employment.CHAPTER 9Introduction to Economic Fluctuationsslide 12Supply shocksA supply shock alters production costs, affects the prices that firms charge. (also called price shocks )Examples of adverse supply shocks:Bad weather reduces crop yields, pushing up food prices.Workers unionize, negotiate wage increases. New environmental regulations require firms to reduce emissions. Firms charge higher prices to help cover the costs of compliance. (Favorable supply shocks lower costs and prices.)CHAPTER 9Introduction to Economic Fluctuationsslide 13CASE STUDY:The 1970s oil shocksEarly 1970s: OPEC coordinates a reductionin the supply of oil.Oil prices rose11% in 197368% in 197416% in 1975Such sharp oil price increases are supplyshocks because they significantly impact production costs and prices.CHAPTER 9Introduction to Economic Fluctuationsslide 141PSRAS 1YP ADLRASYY 2The oil price shock shifts SRAS up, causing output and employment to fall. BIn absence of further priceshocks, prices will fall over time and economy moves back toward full employment.2P SRAS 2CASE STUDY:The 1970s oil shocksACHAPTER 9Introduction to Economic Fluctuationsslide 15Stabilization policydef: policy actions aimed at reducing the severity of short-run economic fluctuations. Example: Using monetary policy tocombat the effects of adverse supply shocks:CHAPTER 9Introduction to Economic Fluctuationsslide 16Stabilizing output with monetary policy1P SRAS 1Y PAD 1B2P SRAS 2AY 2LRASYThe adverse supply shock moves the economy to point B.CHAPTER 9Introduction to Economic Fluctuationsslide 17Stabilizing output with monetary policy1P YPAD 1B2P SRAS 2AC Y 2LRASYAD 2But the Fed accommodates the shock by raising agg. demand.results:P is permanently higher, but Yremains at its full-employment level.CHAPTER 9Introduction to Economic Fluctuationsslide 18More on stabilization policy latermacroeconomics fifth editionN. Gregory MankiwPowerPoint ®Slidesby Ron CronovichCHAPTER TENAggregate Demand Im a c r o© 2003 Worth Publishers, all rights reservedCHAPTER 10Aggregate Demand Islide 20Where are we?Chapter 9 introduced the model of aggregate demand and aggregate supply.Long run–prices flexible–output determined by factors of production & technology–unemployment equals its natural rate Short run–prices fixed–output determined by aggregate demand –unemployment is negatively related to outputCHAPTER 10Aggregate Demand Islide 21Where are we?This chapter develops the IS-LM model, a full blown theory that yields the aggregate demand curve.We focus on the short run and assume the price level is fixed.This chapter (and chapter 11) focus on the closed-economy case. Chapter 12 presents the open-economy case.CHAPTER 10Aggregate Demand Islide 22The Keynesian CrossA simple closed economy model in whichincome is determined by expenditure. (due to J.M. Keynes)This is a historical model. We use it to build up theIS curve (to be defined later)CHAPTER 10Aggregate Demand Islide 23The Keynesian CrossBack for a moment to CH. 3:Y = C + I + GIntroduce new piece of notation:E = C + I + G = planned expenditureY = real GDP = actual expenditureWe want to emphasize now that actual and planned expendituremay be different in the short run.Difference between actual & planned expenditure: unplanned inventories (firms stock up more units of goods they intended toif sales are less than expected, or they deplete their “normal” level of inventories should there be higher than expected demand).CHAPTER 10Aggregate Demand Islide 24Elements of the Keynesian Cross=−=−()()C C Y T MPC Y T I I=,G G T T===−++()E MPC Y T I G Actual expenditure Planned expenditureY E==consumption function:for now, investment isexogenous:planned expenditure:Equilibrium condition:govt policy variables:CHAPTER 10Aggregate Demand Islide 25Graphing planned expenditureincome, output,YEplanned expenditureE =C +I +GMPC⋅I +G -MPC T=−++()E MPC Y T I GCHAPTER 10Aggregate Demand Islide 26Graphing the equilibrium conditionincome, output,YEplannedexpenditureE =Y 45ºCHAPTER 10Aggregate Demand Islide 27The equilibrium value of incomeincome, output,YEplanned expenditureE =YE =C +I +GEquilibrium incomeCHAPTER 10Aggregate Demand Islide 28Equilibrium in the Keynesian crossmodelThe equilibrium as defined in this modelcorresponds to the equilibrium level of output that we defined and determined in chapter 3, only seen in a different way here.The main difference is that here we focuson the short term, during which output can move away from its full employment equilibrium level (up or down).CHAPTER 10Aggregate Demand Islide 29Example: An increase in governmentpurchasesYEE =YE =C +I +G 1E 1= Y 1E =C +I +G 2E 2= Y 2∆YAt Y 1,there is now an unplanned drop in inventory……so firmsincrease output, and income rises toward a new equilibrium∆GCHAPTER 10Aggregate Demand Islide 30Solving for ∆Y=⋅−++()Y MPC Y T I G−=−⋅++1()Y MPC MPC T I G ()∆=−⋅∆+∆+∆−11()Y MPC T I G MPC ()=−⋅++−11()Y MPC T I G MPC 11MPC Y G⎛⎞∆=×∆⎜⎟−⎝⎠equilibrium conditionRemember, T and I did not change.CHAPTER 10Aggregate Demand Islide 31The government purchases multiplierExample: If MPC = 0.8, thenDefinition: the increase in income resultingfrom a $1 increase in G .In this model, the govt purchases multiplier equals 11MPC Y G ∆=∆−1510.8Y G ∆==∆−An increase in Gcauses income to increase by 5 timesas much!CHAPTER 10Aggregate Demand Islide 32Why the multiplier is greater than 1Initially, the increase in G causes an equalincrease in Y :∆Y = ∆G . But ↑Y ⇒↑C⇒further ↑Y ⇒further ↑C ⇒further ↑YSo the final impact on income is muchbigger than the initial ∆G .CHAPTER 10Aggregate Demand Islide 34An increase in taxesYEE=YE =C 2+I +GE 2= Y 2E =C 1+I +G E 1= Y 1∆YAt Y 1, there is now an unplannedinventory buildup……so firms reduce output, and income falls toward a new equilibrium∆C = −MPC ∆TInitially, the tax increase reduces consumption, and therefore E :CHAPTER 10Aggregate Demand Islide 35Solving for ∆YY C I G∆=∆+∆+∆()MPC Y T=×∆−∆C=∆(1MPC)MPC Y T−×∆=−×∆eq’m condition in changesI and G exogenousSolving for ∆Y :MPC 1MPC Y T ⎛⎞−∆=×∆⎜⎟−⎝⎠Final result:CHAPTER 10Aggregate Demand Islide 36The Tax Multiplierdef: the change in income resulting from a $1 increase in T :MPC 1MPCY T∆−=∆−0808410802....Y T∆−−===−∆−If MPC = 0.8, then the tax multiplier equalsCHAPTER 10Aggregate Demand Islide 37The Tax Multiplier…is negative :A tax hike reduces consumer spending, which reduces income.…is greater than one (in absolute value ): A change in taxes has a multiplier effect on income.…is smaller than the govt spending multiplier :Consumers save the fraction (1-MPC) of a tax cut, so the initial boost in spending from a tax cut is smaller than from an equal increase in G .CHAPTER 10Aggregate Demand Islide 38The IS -LM modelUntil now, the model is overly simple.The components of expenditure are allexogenous…Now let’s go back and reintroduce theinterest rate, r, in the demand for investment function:I = I (r)CHAPTER 10Aggregate Demand Islide 39Y 2Y 1Effect of a decrease in r↓r ⇒↑IYEE =C +I (r 1)+GE =C +I (r 2)+GE =Y ∆I⇒↑E ⇒↑YThe IS curvedef: a graph of all combinations of r and Y that result in goods market equilibrium,Deriving the IS curveEE =Y E =C +I (r )+G 2i.e. actual expenditure (output)= planned expenditure The equation for the IS curve is:↓r ⇒ ↑I ⇒ ↑E ⇒ ↑Y∆Ir r1 r2E =C +I (r1 )+GY1Y2YY = C ( − T ) + I (r ) + G YIS Y1 Y2Yslide 41CHAPTER 10Aggregate Demand Islide 40CHAPTER 10Aggregate Demand IWhy the IS curve is negatively slopedA fall in the interest rate motivates firms to increase investment spending, which drives up total planned spending (E ). To restore equilibrium in the goods market, output (a.k.a. actual expenditure, Y ) must increase.Fiscal Policy and the IS curveWe can use the IS-LM model to see how fiscal policy (G and T ) can affect aggregate demand and output. Let’s start by using the Keynesian Cross to see how fiscal policy shifts the IS curve…CHAPTER 10Aggregate Demand Islide 42CHAPTER 10Aggregate Demand Islide 4311Shifting the IS curve: ∆GAt any value of r, ↑G ⇒ ↑E ⇒ ↑Y …so the IS curve shifts to the right. The horizontal distance of the IS shift equals 1 ∆Y = ∆G 1 − MPCEE =Y E =C +I (r )+G 1 2E =C +I (r1 )+G1Question is: is the new level of equilibrium output, Y2 really attainable? Will interest rates really stay constant at r1? Introduce now the theory of liquidity preference.A simple theory in which the interest rate is determined by money supply and money demand.CHAPTER 10r r1Y1Y2Y∆YIS1Y1CHAPTER 10Y2IS2 Yslide 44Aggregate Demand IAggregate Demand Islide 45The Theory of Liquidity PreferenceRecall from ch. 4. People choose how to allocate their income between liquid assets (money) and interest-bearing illiquid assets depending on the level of the interest rate. If interest rates go up, they will want to hold less money and more assets such as savings accounts, stocks, bonds, etc.Money SupplyThe supply of real money balances is fixed:rinterest rate(MP)s(MP) =M PsM PM/Preal money balancesslide 47CHAPTER 10Aggregate Demand Islide 46CHAPTER 10Aggregate Demand I12Money DemandDemand for real money balances:rinterest rateEquilibriumP)s(M(MP)d= L (r ,Y )The interest rate adjusts to equate the supply and demand for money:rinterest rate(MP)sL (r ,Y )M PM P = L (r ,Y )r1L (r ,Y)M PM/Preal money balancesslide 48M/Preal money balancesslide 49CHAPTER 10Aggregate Demand ICHAPTER 10Aggregate Demand IThe LM curveThe LM curve is a graph of all combinations of r and Y that equate the supply and demand for real money balances. The equation for the LM curve is:rDeriving the LM curve(a) The market forreal money balances(b) The LM curver LMr2 r1M1 Pr2 L (r , Y2 ) L (r , Y1 )M/PAggregate Demand IM P = L (r ,Y )r1 Y1 Y2YCHAPTER 10Aggregate Demand Islide 50CHAPTER 10slide 5113Why the LM curve is upward-sloping upwardAn increase in income raises money demand. Since the supply of real balances is fixed, there is now excess demand in the money market at the initial interest rate. The interest rate must rise to restore equilibrium in the money market.rHow ∆M shifts the LM curve(a) The market forreal money balances(b) The LM curverLM2 LM1r2 r1M2 P M1 Pr2 L (r , Y1 )M/Pr1 Y1YCHAPTER 10Aggregate Demand Islide 52CHAPTER 10Aggregate Demand Islide 53How the Fed raises the interest raterinterest rateCASE STUDYVolcker’s Monetary TighteningLate 1970s: π > 10% Oct 1979: Fed Chairman Paul Volcker announced that monetary policy would aim to reduce inflation. Aug 1979-April 1980: Fed reduces M/P 8.0%To increase r, Fed reduces Mr2 r1L (r )M2 PCHAPTER 10Jan 1983: π = 3.7%M1 PM/Preal money balancesslide 54How do you think this policy change How do you think this policy change would affect interest rates? would affect interest rates?CHAPTER 10Aggregate Demand IAggregate Demand Islide 5514Volcker’s Monetary Tightening, cont.The effects of a monetary tightening on nominal interest ratesshort run model prices prediction actual outcomeCHAPTER 10The short-run equilibrium shortThe short-run equilibrium is the combination of r and Y that simultaneously satisfies the equilibrium conditions in the goods & money markets:r LMlong run Quantity Theory, Fisher Effect(Classical)Liquidity Preference(Keynesian)sticky ∆i > 0 8/1979: i = 10.4% 4/1980: i = 15.8%Aggregate Demand Iflexible ∆i < 0 1/1983: i = 8.2%slide 56Y = C ( − T ) + I (r ) + G YIS YM P = L (r ,Y )Equilibrium interest rateCHAPTER 10Equilibrium level of incomeslide 57Aggregate Demand IChapter summary1. Keynesian CrossChapter summary3. Theory of Liquidity Preferencebasic model of income determination takes fiscal policy & investment as exogenous fiscal policy has a multiplier effect on income.2. IS curvebasic model of interest rate determination takes money supply & price level as exogenous an increase in the money supply lowers the interest rate4. LM curvecomes from Keynesian Cross when planned investment depends negatively on interest rate shows all combinations of r and Y that equate planned expenditure with actual expenditure on goods & servicesCHAPTER 10comes from Liquidity Preference Theory when money demand depends positively on income shows all combinations of r andY that equate demand for real money balances with supplyCHAPTER 10Aggregate Demand Islide 58Aggregate Demand Islide 5915Chapter summary5. IS-LM modelPreview of Chapter 11In Chapter 11, we will use the IS-LM model to analyze the impact of policies and shocks learn how the aggregate demand curve comes from IS-LM use the IS-LM and AD-AS models together to analyze the short-run and long-run effects of shocks use our models to learn about the Great DepressionCHAPTER 10Intersection of IS and LM curves shows the unique point (Y, r ) that satisfies equilibrium in both the goods and money markets.CHAPTER 10Aggregate Demand Islide 60Aggregate Demand Islide 6116。

ECON1001-总复习重点摘要

ECON1001总复习重点摘要
Part 1basicsand demand &supply
1.PPF：（Production Possibilities Frontier）
Represents the possible combinations of two goods that can be produced in a certain period of time under the conditions of a given state of technology and fully employed resources.（表示在给定技术状态和充分利用的资源的条件下，在一定时间段内可以生产的两种货物的可能组合apples rises, the supply of apples will rise.” True or false? Explain your answer.
False.If the price of apples rises, thequantity suppliedof apples will rise—not thesupplyof apples.We are talking about amovementfrom one point on a supply curve to a point higher upon the supply curve and not about a shift in the supply curve.
Part2 summary of Elasticities
1.TR（total revenue）=PxQ(看横纵坐标与线上点围成矩形的面积大小)
2.Number of substitutes：一个商品的替代品越多，需求的价格弹性越高（更具体的商品具有更多的代替品）

INTRODUCTIONARY MICROECONOMICS Opportunity costs

Opportunity costs and economic growthO u t l i n eDefine opportunity costsUse a production possibilities frontier toillustrate:Trade-offs or opportunity costsProduction efficiencyHow current production influenceseconomic growthReading (required) – Ch. 1 & 2 TF(suggested) Borland 1.1C h o i c e a n d o p p o r t u n i t y c o s tScarce resources and unlimited wantsThe need to make choices for individuals,governments, business …Choices involve trade-offs or opportunitycostsThe value of the next best alternativeforegone (see esp. Borland 1.1)Includes explicit AND implicit costs –cost of going to Uni., running a business.R e s o u r c e sLandLabourPhysical and mental effortCapitalGoods we use to produce other good & servicesIncludes physical capital – buildings,machinery, roads & other equipmentHuman capital – knowledge & skill thatindividuals gain from education & workP r o d u c t i o n p o s s i b i l i t i e sThe production possibilities frontier (PPF) Shows which combinations of goods & servicescan be producedDescribes the set of possible output choiceswhen limited resources are used efficientlyProduction efficiency is achieved when it is notpossible to produce more of one good withoutproducing less of some other goodsPoints inside the PPF are inefficient, i.e. someunused resourcesP r o d u c t i o n p o s s i b i l i t i e s (c o n t )Guns ButterA 0 25000B 100 24000C 200 22000D 300 18000E 400 13000F 500 0I n c r e a s i n g o p p o r t u n i t yc o s t o f g u n sP r o d u c t i o n p o s s i b i l i t i e s c u r v eButterGunsP r o d u c t i o n p o s s i b i l i t i e s c u r v eO p p o r t u n i t y C o s t sAn opportunity cost is the highest valuealternative forgoneOC increase as we produce more of onegoodWhy? Because not all resources are equallyproductive in all activities.Hence the shape of the PPF – it is bowedoutwards or is ‘concave to the origin’P r o d u c t i o n p o s s i b i l i t i e s c u r v eE c o n o m i c g r o w t hReflects an economy’s expansion over timeTwo factorsTechnological change, i.e. the development ofnew goods (and services) and better ways ofproducing themCapital accumulation. That is, the growth ofcapital resources such as factories,infrastructure, human capital etc.E c o n o m i c g r o w t h a n d t h e P P F/P P CS c a r c i t y , c h o i c e a n d e c o n o m i c g r o w t hI n v e s t m e n t g o o d sConsumption goodsT h r e e q u e s t i o n sWhat is to be produced?Where on the PPC should the economy be?How should goods be produced?How can resources be used efficiently?For whom are goods produced?A question of allocationS u m m a r yOpportunity costsValue of next best alternative foregone?Production possibilitiesIllustrate feasible productionShow opportunity costs。

曼昆宏观经济学教案Ecn101_lecture23-24

CHAPTER TWELVEmacrorCHAPTER 12Econ 101: Intermediate Macro TheoryLecture notes Professor Cetorelli UC Davis Fall 2003Lecture 22-240Aggregate Demand in the Open Economymacroeconomics fifth editionN. Gregory MankiwPowerPoint® Slides by Ron Cronovich© 2003 Worth Publishers, all rights reservedLearning objectivesThe Mundell-Fleming model: IS-LM for the small open economy Analysis of small open economy in the short run. Hence, prices of goods, both domestic and foreign, are assumed to be fixed.Key assumption:Small open economy with perfect capital mobility.r = r*r > r* Capital inflows r down again Purchase of US bondsr = r*r < r* Capital outflows Sale of US bonds to buy Foreign bonds r up again Capital flowsCHAPTER 12Aggregate Demand in the Open Economyslide 2Aggregate Demand in the Open Economyslide 31The Mundell-Fleming Model MundellThis assumption is really important in this context. It changes dramatically the way variables interact with each other and how policy may affect the macroeconomic equilibriumGoods market equilibrium---the IS* curve:Y = C (Y − T ) + I (r *) + G + NX (e )where e = nominal exchange rate = foreign currency per unit of domestic currency Remember: P and P* are by assumption fixed, so we can focus on nominal exchange rate.slide 4CHAPTER 12Aggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 5The IS* curve: Goods Market Eq’mY = C (Y − T ) + I (r *) + G + NX (e )Please pay attention to which variables are now on the axes! We now describe the equilibrium in the space of e and Y.The LM* curve: Money Market Eq’mM P = L (r *,Y )The LM* curve is drawn for a given value of r* is vertical because: given r*, there is only one value of Y that equates money demand with supply, regardless of e.CHAPTER 12eeLM*The IS* curve is drawn for a given value of r*. Intuition for the slope:IS* YY↓ e ⇒ ↑ NX ⇒ ↑ YCHAPTER 12Aggregate Demand in the Open Economyslide 6Aggregate Demand in the Open Economyslide 72Equilibrium in the Mundell-Fleming model MundellY = C (Y − T ) + I (r *) + G + NX (e )Floating & fixed exchange ratesIn a system of floating exchange rates, e is allowed to fluctuate in response to changing economic conditions. In contrast, under fixed exchange rates, the central bank trades domestic for foreign currency at a predetermined price. We now consider fiscal, monetary, and trade policy: first in a floating exchange rate system, then in a fixed exchange rate system.M P = L (r *,Y )e LM*equilibrium exchange rate equilibrium level of incomeCHAPTER 12IS*YAggregate Demand in the Open Economyslide 8CHAPTER 12Aggregate Demand in the Open Economyslide 9Fiscal policy under floating exchange ratesY = C (Y − T ) + I (r *) + G + NX (e )Intuition for the results:As we learned in earlier chapters, a fiscal expansion puts upward pressure on the country’s interest rate. In a small open economy with perfect capital mobility, as soon as the domestic interest rate rises even the tiniest bit about the world rate, tons of foreign (financial) capital will flow in to take advantage of the rate difference.M P = L (r *,Y )At any given value of e, a fiscal expansion increases Y, shifting IS* to the right. Results: ∆e > 0, ∆Y = 0eLM 1*e2e1IS 2*IS 1*Y1YCHAPTER 12Aggregate Demand in the Open Economyslide 10CHAPTER 12Aggregate Demand in the Open Economyslide 113Intuition for the results:But for foreigners to buy these U.S. bonds, they must first acquire U.S. dollars. Hence, the capital inflows result in an increase in foreign demand for dollars in the foreign exchange market, causing the dollar to appreciate. This appreciation makes exports more expensive to foreigners, and imports cheaper to people at home, and thus causes NX to fall. The fall in NX offsets the effect of the fiscal expansion.CHAPTER 12Lessons about fiscal policyIn a small open economy with perfect capital mobility and floating exchange rates, fiscal policy cannot affect real GDP. “Crowding out” • closed economy: Fiscal policy crowds out investment by causing the interest rate to rise. • small open economy: Fiscal policy crowds out net exports by causing the exchange rate to appreciate.CHAPTER 12Aggregate Demand in the Open Economyslide 12Aggregate Demand in the Open Economyslide 13Mon. policy under floating exchange ratesY = C (Y − T ) + I (r *) + G + NX (e )Intuition for the results:Initially, the increase in the money supply puts downward pressure on the interest rate. (In a closed economy, the interest rate would fall.) Because the economy is small and open, when the interest rate tries to fall below r*, savers send their loanable funds to the world financial market.M P = L (r *,Y )eAn increase in M shifts LM* right because Y must rise to restore eq’m in the money market. Results: ∆e < 0, ∆Y > 0LM 1*LM 2*e1 e2 IS 1* Y1 Y2 YThis capital outflow causes the exchange rate to fall, which causes NX-- and hence Y--to increase.CHAPTER 12CHAPTER 12Aggregate Demand in the Open Economyslide 14Aggregate Demand in the Open Economyslide 154Lessons about monetary policyMonetary policy affects output by affecting one (or more) of the components of aggregate demand: closed economy: ↑M ⇒ ↓r ⇒ ↑I ⇒ ↑Y small open economy: ↑M ⇒ ↓e ⇒ ↑NX ⇒ ↑Y Expansionary monetary policy does not raise world aggregate demand, it shifts demand from foreign to domestic products. Thus, the increases in income and employment at home come at the expense of losses abroad.CHAPTER 12Trade policy under floating exchange ratesY = C (Y − T ) + I (r *) + G + NX (e )M P = L (r *,Y )At any given value of e, a tariff or quota reduces imports, increases NX, and shifts IS* to the right. Results: ∆e > 0, ∆Y = 0CHAPTER 12e e2 e1LM 1*IS 2*IS 1* Y1YAggregate Demand in the Open Economyslide 16Aggregate Demand in the Open Economyslide 17Lessons about trade policyImport restrictions cannot reduce a trade deficit. Even though NX is unchanged, there is less trade: – the trade restriction reduces imports – the exchange rate appreciation reduces exports Less trade means fewer ‘gains from trade.’ Import restrictions on specific products save jobs in the domestic industries that produce those products, but destroy jobs in export-producing sectors. Hence, import restrictions fail to increase total employment. Worse yet, import restrictions create “sectoral shifts,” which cause frictional unemployment.CHAPTER 12Fixed exchange ratesUnder a system of fixed exchange rates, the country’s central bank stands ready to buy or sell the domestic currency for foreign currency at a predetermined rate. In the context of the Mundell-Fleming model, the central bank shifts the LM* curve as required to keep e at its preannounced rate. This system fixes the nominal exchange rate. In the long run, when prices are flexible, the real exchange rate can move even if the nominal rate is fixed.CHAPTER 12Aggregate Demand in the Open Economyslide 18Aggregate Demand in the Open Economyslide 195Fiscal policy under fixed exchange ratesUnder floating rates, a fiscal expansion would policy ineffective at changing output. raise e. To keep e from rising, Under fixed rates, the central bank must fiscal policy is very sell domestic currency, effective at changing output. which increases M and shifts LM* right. Results:Mon. policy under fixed exchange ratesAn increase in M would shift Under floating rates, LM* right policy is very . monetary and reduce e effective at changing e To prevent the fall in e, output. the central bank must Under fixed rates, buy domestic currency, monetary policy cannot be e1 which reduces M and used to affect output. shifts LM* back left.eLM 1*LM 2*LM 1*LM 2*e1 IS 2* IS 1* Y1 Y2∆e = 0, ∆Y > 0CHAPTER 12YResults: ∆e = 0, ∆Y = 0CHAPTER 12IS 1* Y1YAggregate Demand in the Open Economyslide 20Aggregate Demand in the Open Economyslide 21Trade policy under fixed exchange ratesUnder floating rates, A restriction on imports import restrictions do not puts upward pressure affecte. or NX. on Y Under fixed rates, rising, To keep e from importcentral bank must the restrictions increase Y and NX. sell domestic currency, But, these gains come at which increases M the expense LM* right. and shifts of other countries, as the policy Results: merely shifts demand from foreign to = 0, ∆Y goods. ∆e domestic > 0CHAPTER 12M-F: summary of policy effectstype of exchange rate regime:eLM 1*LM 2*floatingfixedimpact on: PolicyY0↑e↑ ↓ ↑NX↓ ↑Y↑e0 0 0NX0 0↑e1 IS 2* IS 1* Y1 Y2fiscal expansion mon. expansion0↑Yimport restrictionCHAPTER 1200Aggregate Demand in the Open Economyslide 22Aggregate Demand in the Open Economyslide 236Fixed exchange ratesUnder a system of fixed exchange rates, the country’s central bank stands ready to buy or sell the domestic currency for foreign currency at a predetermined rate. In the context of the Mundell-Fleming model, the central bank shifts the LM* curve as required to keep e at its preannounced rate. This system fixes the nominal exchange rate. In the long run, when prices are flexible, the real exchange rate can move even if the nominal rate is fixed.CHAPTER 12Fiscal policy under fixed exchange ratesUnder floating rates, a fiscal expansion would policy ineffective at changing output. raise e. To keep e from rising, Under fixed rates, the central bank must fiscal policy is very sell domestic currency, effective at changing output. which increases M and shifts LM* right. Results:eLM 1*LM 2*e1 IS 2* IS 1* Y1 Y2∆e = 0, ∆Y > 0slide 24YAggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 25Mon. policy under fixed exchange ratesAn increase in M would shift Under floating rates, LM* right policy is very . monetary and reduce e effective at changing e To prevent the fall in e, output. the central bank must Under fixed rates, buy domestic currency, monetary policy cannot be e1 which reduces M and used to affect output. shifts LM* back left. Results: ∆e = 0, ∆Y = 0CHAPTER 12Trade policy under fixed exchange ratesUnder floating rates, A restriction on imports import restrictions do not puts upward pressure affecte. or NX. on Y Under fixed rates, rising, To keep e from importcentral bank must the restrictions increase Y and NX. sell domestic currency, But, these gains come at which increases M the expense LM* right. and shifts of other countries, as the policy Results: merely shifts demand from foreign to = 0, ∆Y goods. ∆e domestic > 0CHAPTER 12LM 1*LM 2*eLM 1*LM 2*e1 IS 2* IS 1* Y1 Y2IS Y1* 1YYAggregate Demand in the Open Economyslide 26Aggregate Demand in the Open Economyslide 277M-F: summary of policy effectstype of exchange rate regime:floating fixedInterest-rate differentials InterestTwo reasons why r may differ from r*country risk:impact on: Policyfiscal expansion mon. expansion import restrictionCHAPTER 12Y0↑e↑ ↓ ↑NX↓ ↑Y↑e0 0 0NX0 0↑The risk that the country’s borrowers will default on their loan repayments because of political or economic turmoil. Lenders require a higher interest rate to compensate them for this risk.expected exchange rate changes:0↑00If a country’s exchange rate is expected to fall, then its borrowers must pay a higher interest rate to compensate lenders for the expected currency depreciation.slide 28Aggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 29Differentials in the M-F model Mr = r *+ θwhere θ is a risk premium. Substitute the expression for r into the IS* and LM* equations:The effects of an increase in θIS* shifts left, because ↑ θ ⇒ ↑r ⇒ ↓ I LM* shifts right, because ↑ θ ⇒ ↑r ⇒ ↓(M/P )d, so Y must rise to restoremoney market eq’m.e e1 e2LM 1*LM 2*Y = C (Y − T ) + I (r * + θ ) + G + NX (e )M P = L (r * + θ ,Y )Results: ∆e < 0, ∆Y > 0CHAPTER 12Y1 Y2IS 1* IS 2* YAggregate Demand in the Open Economyslide 30CHAPTER 12Aggregate Demand in the Open Economyslide 318The effects of an increase in θThe fall in e is intuitive: An increase in country risk or an expected depreciation makes holding the country’s currency less attractive.Why income might not riseThe central bank may try to prevent the depreciation by reducing the money supply The depreciation might boost the price of imports enough to increase the price level (which would reduce the real money supply) Consumers might respond to the increased risk by holding more money. Each of the above would shift LM* leftward.Note: an expected depreciation is a self-fulfilling prophecy.The increase in Y occurs because the boost in NX (from the depreciation) is even greater than the fall in I (from the rise in r ).CHAPTER 12Aggregate Demand in the Open Economyslide 32CHAPTER 12Aggregate Demand in the Open Economyslide 33CASE STUDY:CASE STUDY:The Mexican Peso Crisis35 35The Mexican Peso CrisisU.S. Cents per Mexican PesoU.S. Cents per Mexican Peso303025252020151510 7/10/948/29/9410/18/9412/7/941/26/953/17/955/6/9510 7/10/948/29/9410/18/9412/7/941/26/953/17/955/6/95CHAPTER 12Aggregate Demand in the Open Economyslide 34CHAPTER 12Aggregate Demand in the Open Economyslide 359The Peso Crisis didn’t just hurt MexicoU.S. goods more expensive to Mexicans – U.S. firms lost revenue – Hundreds of bankruptcies along U.S.-Mex border Mexican assets worth less in dollars – Affected retirement savings of millions of U.S. citizensUnderstanding the crisisIn the early 1990s, Mexico was an attractive place for foreign investment. During 1994, political developments caused an increase in Mexico’s risk premium (θ ): • peasant uprising in Chiapas • assassination of leading presidential candidate Another factor: The Federal Reserve raised U.S. interest rates several times during 1994 to prevent U.S. inflation. (So, ∆r* > 0)CHAPTER 12Aggregate Demand in the Open Economyslide 36CHAPTER 12Aggregate Demand in the Open Economyslide 37Understanding the crisisThese events put downward pressure on the peso. Mexico’s central bank had repeatedly promised foreign investors that it would not allow the peso’s value to fall, so it bought pesos and sold dollars to “prop up” the peso exchange rate. Doing this requires that Mexico’s central bank have adequate reserves of dollars. Did it?CHAPTER 12Dollar reserves of Mexico’s central bankDecember 1993 ……………… $28 billion December 1993 ……………… $28 billion August 17, 1994 ……………… $17 billion August 17, 1994 ……………… $17 billion December 1, 1994 …………… $ 9 billion December 1, 1994 …………… $ 9 billion December 15, 1994 ………… $ 7 billion December 15, 1994 ………… $ 7 billionDuring 1994, Mexico’s central bank hid the fact that its reserves were being depleted.slide 38Aggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 3910the disasterDec. 20: Mexico devalues the peso by 13% (fixes e at 25 cents instead of 29 cents) Investors are shocked ! ! ! …and realize the central bank must be running out of reserves… ↑θ, Investors dump their Mexican assets and pull their capital out of Mexico. Dec. 22: central bank’s reserves nearly gone. It abandons the fixed rate and lets e float. In a week, e falls another 30%.CHAPTER 12The rescue package1995: U.S. & IMF set up $50b line of credit to provide loan guarantees to Mexico’s govt. This helped restore confidence in Mexico, reduced the risk premium. After a hard recession in 1995, Mexico began a strong recovery from the crisis.Aggregate Demand in the Open Economyslide 40CHAPTER 12Aggregate Demand in the Open Economyslide 41The S.E. Asian Crisisexchange rate stock market % nominal GDP % change from change from % change 7/97 to 1/98 7/97 to 1/98 1997-98 Indonesia Japan Malaysia Singapore S. Korea Taiwan Thailand U.S.CHAPTER 12Floating vs. Fixed Exchange RatesArgument for floating rates: allows monetary policy to be used to pursue other goals (stable growth, low inflation) Arguments for fixed rates: avoids uncertainty and volatility, making international transactions easier disciplines monetary policy to prevent excessive money growth & hyperinflation-59.4% -12.0% -36.4% -15.6% -47.5% -14.6% -48.3%-32.6% -18.2% -43.8% -36.0% -21.9% -19.7% -25.6%-16.2% -4.3% -6.8% -0.1% -7.3% n.a. -1.2%(1996-97)slide 42n.a. 2.7% 2.3% Aggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 4311Mundell-Fleming and the AD curve MundellSo far in M-F model, P has been fixed. Next: to derive the AD curve, consider the impact of a change in P in the M-F model. We now write the M-F equations as:(IS* )Deriving the AD curveWhy AD curve has negative slope: ↑P ⇒ ↓(M/P ) ⇒ LM shifts left ⇒ ↑ε ⇒ ↓NXPP2 P1 AD Y2 Y1εLM*(P2) LM*(P1)ε2 ε1IS* Y2 Y1Y = C (Y − T ) + I (r *) + G + NX (ε )Y(LM* )M P = L (r *,Y )(Earlier in this chapter, P was fixed, so we could write NX as a function of e instead of ε.)CHAPTER 12⇒ ↓YYslide 45Aggregate Demand in the Open Economyslide 44CHAPTER 12Aggregate Demand in the Open EconomyFrom the short run to the long runIf Y1 < Y ,then there is downward pressure on prices. Over time, P will move down, causing (M/P )↑Large: between small and closedMany countries - including the U.S. - are neither closed nor small open economies. A large open economy is in between the polar cases of closed & small open. Consider a monetary expansion: • Like in a closed economy, ∆M > 0 ⇒ ↓r ⇒ ↑I (though not as much) • Like in a small open economy, ∆M > 0 ⇒ ↓ε ⇒ ↑NX (though not as much)εLM*(P1) LM*(P2)ε1 ε2IS*PP1 P2Y1Y LRASYSRAS1 SRAS2 ADε↓NX ↑Y↑Y1CHAPTER 12YYslide 46Aggregate Demand in the Open EconomyCHAPTER 12Aggregate Demand in the Open Economyslide 4712。

Green-pumped picosecond MgOPPLN optical parametric oscillator

Green-pumped, picosecond MgO:PPLN opticalparametric oscillatorFlorian Kienle,1,* Dejiao Lin,1 Shaif-ul Alam,1 Hazel S. S. Hung,2 Corin B. E. Gawith,2 Huw E. Major, 2 David J. Richardson1, David P. Shepherd11Optoelectronics Research Centre, University of Southampton, Highfield, Southampton, SO171BJ, UK2Covesion Ltd., Romsey, SO51 9DG, UK*Corresponding author: flk@We investigate the performance of a magnesium-oxide-doped periodically poled lithium niobate crystal (MgO:PPLN) in an optical parametric oscillator (OPO) synchronously-pumped by 530nm, 20ps, 230MHz pulses with an average power of up to 2W from a frequency-doubled, gain-switched laser diode seed and a multi-stage Yb:fiber amplifier system. The OPO produces ~165mW (signal, 845nm) and ~107mW (idler, 1421nm) of average power for ~1W of pump power and can be tuned from ~800nm to 900nm (signal) and 1.28µm to 1.54µm (idler). Observations of photo-refraction and green-induced infrared absorption (GRIIRA) in different operational regimes of the MgO:PPLN OPO are described and the role of peak intensity and average power are investigated, both with the aim to find the optimal operating regime for pulsed systems.OCIS codes: 190.0190, 190.4970, 190.4400, 140.7090, 060.2320.1 IntroductionTunable ultrashort pulses in the visible (VIS) and near-infrared (NIR) spectral range have a multitude of applications including coherent anti-Stokes Raman scattering (CARS) spectroscopy [1-4] and stimulated-emission-depletion (STED) microscopy [5]. Ti:Sapphire lasers have been the source-of-choice in the past, but cheaper, more compact, user-friendly alternatives covering this wavelength region are increasingly sought-after. In CARS, synchronously-pumped OPOs are an ideal choice as they emit two temporally synchronous pulses at different (and tunable) wavelengths. The pump sources used for these OPOs are typically ultrashort solid-state laser systems operating at ~1µm and frequency-doubled to the green.For green-pumped OPOs that produce NIR wavelengths, bulk crystals such as lithium triborate (LBO) offer high damage thresholds and wide transparency ranges, but only moderate values of effective nonlinearity (gain). LBO has long been the preferred nonlinear crystal for high-power, pulsed OPOs, mainly due to its high damage threshold of >10GW/cm2 and the possibility of non-critical birefringent phase-matching [6-9]. The highest signal output power recorded from a picosecond LBO OPO of 1.6W tunable from 744nm to 930nm was reported by Tukker et al. [9] using 5.6W of pump power from a frequency-doubled, 50ps Nd:YLF laser. Master-oscillator power-amplifier (MOPA) configurations based on ytterbium-doped fibers (Yb:fiber), rather than bulk solid-state laser systems, have also been used as pump sources in recent years including reports of picosecond [4] and femtosecond [1] systems delivering hundreds of milliwatts of OPO average output power with signal tunability over ~200nm in the NIR.1Quasi-phase-matched (QPM) materials such as periodically-poled lithium niobate (PPLN), lithium tantalate (PPLT) and potassium titanyl phosphate (PPKTP) offer large nonlinear coefficients and are a popular choice for 1µm-pumped OPOs for mid-infrared (MIR) generation. However, in the presence of visible light, common QPM materials are more sensitive to optical damage mechanisms such as photo-refraction, GRIIRA, nonlinear absorption and/or grey-tracking, which at high pulse energies can result in reduced conversion efficiencies, degraded beam qualities, higher oscillation thresholds, temporal instabilities or even physical crystal damage. Photo-refractive effects cause a distorted refractive index profile [10-12]. High intensities in the VIS generate free charge carriers through photo-ionization and the associated electric field induces a refractive index distortion via the linear electro-optic effect. In the case of lithium niobate (LN), the induced absorption due to GRIIRA originates from color center creation, crystal impurities (mainly Fe-ions), intrinsic defects (Nb-ions occupying Li-ion sites) and the polaron effect [13-15]. Since the absorption of the NIR power grows quadratically with incident green power [13], GRIIRA can become a major problem when power-scaling OPOs. Furthermore, Hirohashi et al. report that both linear and nonlinear (e. g. two-photon) absorption, the latter especially in picosecond experiments, can occur in ferroelectric materials such as LN [15]. Impurities and defects can lead to linear absorption, whereas nonlinear absorption is possible because of the specific band gap of ferroelectrics. In any case, the absorbed energy leads to thermal lensing and consequently resonator instability and degraded beam quality.With improved material properties and advanced fabrication techniques, photo-refraction and GRIIRA in LN can be reduced resulting in an increased damage threshold. To improve the performance of LN under the influence of high intensities in the VIS, a stoichiometric composition [12], where the concentration of Li- and Nb-ions is balanced, can be used. Alternatively, MgO-doping of congruent material, where Mg-ions replace Nb anti-site defects [16], has similar performance benefits. MgO:PPLN has been successfully used in green-pumped CW OPOs [17, 18] as well as in CW second-harmonic generation (SHG) experiments with green average powers of up to 3W for shorter periods of time [19] and 2.2W over more than 2000h [20]. However, due to the onset of photo-refraction and GRIIRA and the high peak powers, there has been limited research activity with ultrashort-pulsed, green-pumped OPOs based on LN. Some work with PPLN in the ultrashort-pulse regime has been carried out previously [21] resulting in the demonstration of ~2ps, 120MHz pulses at a quasi-CW power of 140mW with a total tuning range from 883nm to 1285nm using a mode-locked Nd:YLF laser and amplifier, whose output is frequency-doubled using LBO. However, to access higher peak powers in the kilowatt range from the amplifier, 10µs / 2kHz pulses were sliced from the seed picosecond pulse train and therefore the average power into the crystal was 50× reduced. More recently, MgO:PPLN has been used in a picosecond, 80MHz, green-pumped OPO for CARS spectroscopy producing ~30mW of signal and ~30mW of idler power over a tunability range of 880nm to 1040nm and 1090nm to 1350nm, respectively [22].LN remains an interesting candidate for green-pumped, ultrashort-pulse OPOs, because of the above-mentioned material improvements and its well-known attractive QPM properties (high effective nonlinear coefficient d eff = 17pm/V and designer phase-matching [23]), well-understood physical and optical properties, wide availability and low price. Previously, we have shown that MgO:PPLN is well suited for ultrashort OPOs pumped at 1µm operating at high average powers >10W [24] and at high pulse energies >0.5µJ [25]. In addition to this, experiments performed at Covesion Ltd. have demonstrated CW SHG with MgO:PPLN generating >2W of green (>200kW/cm2) without any impairments in performance over 2000h [20]. Consequently, we now want to investigate the optimal operation regime for MgO:PPLN when used in ultrashort-pulse, green-pumped OPOs.2In this contribution, we demonstrate an MgO:PPLN OPO synchronously pumped with 530nm, 20ps, 230MHz pulses from a frequency-doubled, fiber-amplified, gain-switched laser diode MOPA system producing ~270mW of combined output power for ~1W of pump power. We discuss the limiting effects of photo-refraction, GRIIRA and nonlinear absorption and their associated thresholds. We distinguish between optical damage, i.e. a reversible effect due to photo-refraction, and physical damage, i.e. an irreversible facet or bulk damage, and also show that the limitations are both intensity and average power based and hence quasi-CW mode-locked operation is favored. The damage thresholds of LN vary largely in the literature (see for example [26]) and no safe operation regime can be clearly designated, particularly in the ultrashort-pulse regime. We would thus like to add information to this incomplete picture. The setups of pump source and OPO are described in section 2.A and 2.B, respectively, followed by the OPO experimental results in section 3.A and a discussion / analysis of the performance and damage issues of the MgO:PPLN crystal in section 3.B. Section 4 summarizes and concludes the findings.2. Experimental setupA. Frequency-doubled, fiber-amplified, gain-switched laser diode pump sourceA schematic diagram of the MOPA pump source is shown in Fig. 1, which is very similar to the one described in detail in [27]. The seed source for the fiber amplifiers of the MOPA was a fiber-pigtailed 1060nm Fabry-Perot laser diode (LD) that was gain-switched with a pulsed modulation current superimposed in a bias-tee with a DC current. A mode-selective grating and a chirped fiber Bragg grating (CFBG) were used to achieve self-seeding and to remove the inherent LD chirp, respectively. An electro-optic modulator (EOM) pulse picker was driven by a second pulse generator in order to control the pulse repetition rate over a wide range from ~115MHz to ~920MHz. The modulation signal at 920MHz from the first pulse generator (for gain-switching the LD) served as an external trigger signal for the second pulse generator that reduced this repetition rate by a selectable factor of 2, 4 or 8.The amplification was performed in four polarization-maintaining Ytterbium-doped fiber (YDF) amplifier stages, where the fiberized optical isolators (OI) and the wavelength-multiplexers were also polarization-maintaining. The two pre-amplifiers used 3m-long, single-mode, Yb-doped,5µm core (NA 0.13), 130µm cladding (NA 0.46), core-pumped fibers (PM-YDF-5/130, Nufern, East Granby, USA), pumped by 160mW, 975nm LDs in a forward and a bi-directional scheme, respectively. The third stage used the same type of fiber, but a 9m-long piece, which was backward clad-pumped by a 10W, 975nm LD. The final amplifier employed a 3.5m-long, large-mode-area, Yb-doped, 25µm core (NA 0.06), 250µm cladding (NA 0.46), clad-pumped fiber (PLMA-YDF-25/250-VIII, Nufern, East Granby, USA), which was backward-pumped by a water-cooled, 160W, 975nm LD stack via a simple cylindrical lens combination and an aspherical lens, obtaining a launch efficiency >80% (the only free-space section of the entire MOPA). To ensure single-mode operation, the otherwise multi-mode YDF (V-number >4) was connected to the fiberized OI via a tapered splice [27] and coiled with a diameter of ~7.5cm.34Core-pumped, 3m,Clad-pumped, 9m,Core-pumped, 3m,PulseFigure 1 Schematic diagram of the fiber-amplified gain-switched laser diode MOPA system including the LBO frequency-doubling arrangement. LD = laser diode, CFBG = chirped fiber Bragg grating, EOM = electro-optic modulator, YDF = Ytterbium-doped fiber, DM = dichroic mirror, PBS = polarizing beamsplitter. All fibers, wavelength-division multiplexers and optical isolators were polarization-maintaining.To prevent damage to the output facet and to avoid reflections coupling back into the fiber core, a 2mm-long, angle-polished, mode-expanding end-cap was spliced to the YDF. Dichroic mirrors (DM) were used to separate the pump and signal beams. A polarization extinction ratio of 13dB at the maximum power of ~78W was measured at the MOPA output. The signal beam polarization was controlled with a combination of a half-waveplate and a polarizing beamsplitter (PBS), which also served as a variable amplitude attenuator. The beam quality, also measured after the optical isolator, half-waveplate and PBS, was M 2 ~ 1.25 at an average output power of 35W. The MOPA repetition rate was set to 230MHz, at which a maximum output power of ~90W before the optical isolator, half-waveplate and PBS was obtained, corresponding to ~78W at the MOPA output (pulse energy of 340nJ). The spectra measured at different output power levels did not exhibit significant amplified spontaneous emission (ASE) background with an optical signal-to-noise ratio of >35dB. However, self-phase modulation (SPM) led to a gradual increase of the bandwidth with increasing power. At low power, the FWHM bandwidth was 0.155nm and at the highest output power, the FWHM rose to 0.253nm corresponding to a bandwidth-limited pulse duration of ~6.5ps (assuming a Gaussian pulse) and therefore the measured ~20ps pulses were approximately 3× longer than the bandwidth limit.Frequency-doubling of the 1060nm MOPA output was performed in an AR-coated, 15×3×3mm 3 LBO crystal (Newlight Photonics, Toronto, Canada) cut along the x -axis for type I non-critical phase-matching (θ = 90°, φ = 0°) at a temperature of 154.5°C. At the highest fundamental input power of 77.7W, 33W of second-harmonic power was obtained corresponding to a conversion efficiency of 42%. M 2-values of 1.65 and 1.79 in the crystal z - and y -axis, respectively, were measured. Spectra of the second-harmonic output at different power levels and with the FWHM denoted in brackets are plotted in Fig. 2. At the highest power of 33W, the FWHM was 0.117nm, which is ~6× bandwidth-limited assuming that the green pulses are also ~20ps in duration.To avoid potential problems with power-dependent beam sizes and focus shifts, the MOPA and therefore the LBO output was kept at a constant power level throughout, and the amount of green power used for OPO pumping was controlled with a half-waveplate and PBS variable attenuator.Figure 2brackets.Λ = 6.7, 6.8,T > 99%) and themirror (CM1)mirror (CM2)Figure 3Layout of the singly-resonant (signal), bow-tie OPO ring resonator. The pump beam was focused with a 175mm lens into the center of the MgO:PPLN after reducing its size with a telescope. The radius of curvature of CM1 and CM2 was -250mm. Two output coupler mirrors with signal transmissions of 10% and 3% were available. The mechanical chopper allowed for reduction of the input average power without reduction of the pulse peak power.The resonator was calculated to yield a signal waist radius of ~42µm corresponding to a focusing parameter of ξs = 0.6 (crystal length divided by confocal parameter). A two-lens telescope was used to closely match the pump spot size to the calculated signal spot size. A pump waist with a radius of 44µm and 42µm parallel and perpendicular to the resonator plane, respectively, was obtained corresponding to a focusing parameter of ξp ~ 0.4.3. Results and discussionA. OPO output power and pump depletion vs. pump powerThe signal and idler output power as well as the pump depletion as a function of pump power for two different OPO experiments are presented in this section. Observations of photo-refraction, GRIIRA and/or physical damage of the MgO:PPLN crystal during these experiments are discussed and analyzed in the following section 3.B, but briefly mentioned here in order to clarify the chronology of the experiments.A.1 Full average pump power as input to OPO (no mechanical chopping)In order to clarify the structure of this paper, we comment that ‘full average power’ here means that the input pump beam was not yet mechanically chopped, as was required for the experiments in section 3.A.2 (‘reduced average power’).Initial oscillation of the OPO was achieved by using the 7.1µm poled grating of the MgO:PPLN and the OC with T = 3%. In combination with the temperature of 200°C, a signal wavelength of 808nm was expected using the temperature-dependent Sellmeier equation for MgO:PPLN [30]. The average pump power at 530nm was 2W with an expected threshold of a few hundred milliwatts based on the same analysis as described below. The threshold, however, could not be experimentally confirmed due to the temporally unstable signal and idler output and physical damage in the center of the poled grating after only ~30min of operation.6In the next step, the adjacent 7.0µm grating and considerably less average pump power of maximally 500mW was used, since the oscillation threshold was expected to be relatively low. An analysis of the threshold based on [31] for low-gain (i.e. no output coupling), CW OPOs with arbitrary focusing parameter and on its extension to synchronous pumping [32] yielded an estimated average power threshold value of ~100mW with the assumption of 5% signal power round-trip loss (3% output coupling, 1% crystal AR-coating reflections, 1% diffraction / scattering losses). Fig. 4 shows the signal and idler output power versus the input pump power as well as the pump depletion. The measured threshold pump power was 181mW and the slope efficiencies extracted from the linear curve fits were ~20% for both idler and signal. The pump depletion was not yet saturated at 500mW of pump power, but reached a value between 50% and 60%.The calculated signal and idler wavelengths for 530nm pump wavelength, 7.0µm crystal grating, 200°C crystal temperature were 825nm and 1483nm, respectively. M2-values of 1.41 / 1.34 for the idler and 1.38 / 1.44 for the signal in the planes parallel / perpendicular to the OPO resonator were measured, respectively. The OPO output was still temporally unstable and a more careful optimization of the alignment was not feasible. After a few hours of operation, a dark spot in the center of the green pump spot at the location of the OC mirror was observed. This spot moved up and down relative to the stationary green pump spot, when the crystal was moved up and down. This was a clear indication that it was necessary to further reduce the power that the MgO:PPLN was subjected to.Figure 4To investigate, whether the damage effects observed in the previous section were due to average power (thermally induced) or peak power, a mechanical chopper was introduced to reduce the input pump average power without reducing the pulse peak power. A mechanical chopper with a 1:9 duty cycle and a frequency of 150Hz was placed in the pump beam to transmit 10% and block 90% of the total power (‘transmit’ period 0.67ms, ‘block’ period 6ms). Note that a reduction of the pump source repetition rate to tens of megahertz would have the same effect, but this would be less practical, since a much longer OPO cavity, for example with a fiber for signal feedback [25, 33], and hence a complete re-alignment of the OPO would be7required. During the ‘transmit’ cycle, the peak intensity of the focused picosecond pulses remained unaltered and hence the threshold unaffected. The power values in the graphs shown in Fig. 5 and Fig. 7 are the average powers within the ‘transmit’ cycle, i.e. the measured powers multiplied by a factor of 10. An MgO:PPLN grating period of 6.9µm was used yielding a signal and an idler wavelength of 845nm and 1421nm, respectively. Due to the strongly reduced average power, no optical damage was observed in this experiment using the 3% OC (Fig. 5), despite maintaining high peak power. The threshold was 120mW, the pump depletion ~60% and the slope efficiencies 18% (idler) and 14% (signal).Figure 5Output power and pump depletion versus pump power using a mechanical chopper to reduce the average input power by a factor of 10. The 6.9µm poled grating and the 3% OC were used. All power values plotted represent the average power within the ‘transmit’ cycle of the chopper.Figure 6Fractional deviation around the mean value of the MOPA output (1060nm), the frequency-doubled output (530nm) and the OPO signal output (845nm) over a period of 10min.8Figure 7average power within the ‘transmit’ cycle of the chopper.In order to quantify the power stability of the OPO and also the pump source, the output power from the MOPA (1060nm), the frequency-doubling stage (530nm) and the OPO (signal at 845nm) were recorded over a period of 10min and the fractional deviations from the mean values were plotted (Fig. 6). Polarization drifts of the MOPA, air drifts and temperature fluctuations influence the transmission through the OI and PBS and the LBO conversion efficiency, which was expressed in a fractional deviation of the green power of approximately ±2% compared with ±1% from the MOPA. However, the fractional deviation of the OPO signal output of approximately ±10% could not be solely attributed to the input pump. The OPO was enclosed in a box to reduce air drifts and temperature fluctuations to a minimum. It was suspected that photo-refraction was the main source of the OPO power instability.The 3% OC was then replaced by the 10% OC to extract more signal power from the resonator. The mechanical chopper was still placed in the pump beam. As shown in Fig. 7, the oscillation threshold was 369mW, the pump depletion saturated at ~30% and the slope efficiencies were 16% (idler) and 23% (signal). Signal and idler output powers of 165mW and 107mW, respectively, were obtained at a pump power of 1.05W. The expected signal output power P swhere P pumpλp and λs the pump and signal wavelengths, respectively, T OC the OC transmission and εs the signal power round-trip loss (excluding OC transmission here). At the highest pump power of 1.05W, where the pump depletion was D = 0.33, with the signal wavelength of 845nm and for an estimated loss of εs = 0.05 (4% crystal coating reflections, 1% diffraction / scattering losses), P s was calculated to be 145mW, which was in good agreement with the measured value of 165mW. Once again, no optical damage occurred in these experiments with the 10% OC.Due to the output power instability of the OPO, accurate recordings of spectra with an optical spectrum analyzer were not possible.9B. Nonlinear crystal performance and damage issuesIn this section, we describe and analyze the different damage effects that occurred during the experiments of section 3.A.(2)where P av f rep the repetition rate and w0 the 1/e2-waist radius, assuming a Gaussian spatial beam profile. An overview of the experimental parameters and the observed damage described in the following is given in Table 1.Pump source 532nm CW laser†Frequency-doubled MOPA (20ps, 230MHz, 530nm)Average pump power[W]2 2 0.5 1 → 0.1*1/e2-waist radius[µm2]35×38 44×42 44×42 44×42 49×51 49×51Peak intensity[MW/cm2]0.115 3.757.511 17Crystal grating used[µm]6.77.1 7.0 6.9 6.8 6.8Permanent damage? No Yes(optical +physical)Yes(optical)No Yes(optical)Yes(optical +physical)†no OPO operation*mechanically chopped at 1:9 duty cycle to 0.1WTable 1Summary of the different OPO pump regimes and damage effects observed (optical = dark spots / beam distortion during operation, physical = degradation of the crystal visible with a microscope).B.1 Crystal performance under the influence of the full average pump powerThis section refers to the observations made during the experiments of section 3.A.1, where no mechanical chopper for the pump beam was used.With 2W of average pump power, which corresponds to a peak intensity of ~15MW/cm2, incident for approximately 30min to the 7.1µm grating of the MgO:PPLN crystal, permanent physical damage was visible with the unaided eye. The microscope image in Fig. 8 clearly shows individual, closely spaced damage tracks within a cigar-shaped volume in the center of the MgO:PPLN crystal. This has been reported before and photo-refraction or self-focusing was suspected to cause the damage [34]. The damage is clearly associated with the high intensity pumping region, with the pump waist being located at the center of the crystal. With the equation for the critical power of self-focusing given in [35], a critical power of ~22kW is calculated using the nonlinear refractive index 8.3×10-19m2/W at 532nm [26], the linear refractive index 2.3 at 530nm and assuming a Gaussian beam profile. The peak power of the 20ps long pump pulses was only 435W and, thus, self-focusing can be safely ruled out as the cause for physical damage.10Figure 8Microscope image of the damage within the 7.1µm poled grating, where individual damage tracks are clearly visible.Additionally, the transmitted green pump beam was distorted and had a dark center (region of physical damage) as observed in the green spot on the OC mirror. This beam distortion was previously described as a consequence of photo-refraction [10, 23]. The dark spot within the green spot could be a preceding, more sensitive sign of the physical track formation before it can be seen with a microscope and was possibly not only due to photo-refraction, but also due to GRIIRA. Since a signal and an idler wave in the infrared were generated, GRIIRA could have led to a thermal loading of the crystal and the associated physical damage. The inherent infrared absorption of LN can increase by up to a factor of five with green light present [14] and is quadratically dependent on the green power, but can recover to its initial value after ~20s [13] before physical damage occurs. According to findings in [14], a higher MgO-doping concentration of >6% could help to avoid GRIIRA, because a threshold-like behavior in terms of optical damage has been reported. For a higher concentration, all of the intrinsic Nb5+ anti-site defects (Nb5+-ions at the lattice location of Li+-ions) of congruent LN are replaced by Mg2+-ions. In general, Nb5+ anti-site defects act as electron traps and locally change the absorption properties, referred to as polaron absorption, which is inhibited when Mg2+-ions occupy these anti-site defects. However, MgO:PPLN crystals with doping concentrations >5% suffer from growth defects and can not be grown at high quality, which also impairs the subsequent poling process. Hence, an optimum concentration of 5% is typically used by commercial suppliers. Alternatively, a stoichiometric crystal composition with balanced Nb and Li concentrations could decrease GRIIRA due to the absence of anti-site defects. To confirm whether or not GRIIRA caused the physical damage, an unpoled region of the MgO:PPLN sample was pumped for 30min under the same conditions as above, i.e. 2W of average power and ~15MW/cm2 of peak intensity. Since no parametric oscillation can occur in an unpoled region, no signal or idler in the IR can be generated and hence green-induced IR absorption can not occur. Physical damage of the unpoled region was observed again, which is evidence that processes other than only GRIIRA contribute to the physical damage. Similar to Nb5+ anti-site defects, lattice impurities such as Fe2+-ions can facilitate both linear and nonlinear (e. g. two-photon) absorption [14, 15], which can potentially be a damage contributor [36]. Although the MgO:PPLN sample was of high quality, impurities on the order of parts-per-million naturally occur [12, 36, 37].The 7.0µm grating that was pumped with a 4× lower average power of 0.5W (after damage of the 7.1µm grating at 2W) did not show any signs of visible physical damage after a few hours of OPO operation. However, the beam distortion and the dark spot within the green spot on the OC as described above were again existent. The lower average power and the lower peak intensity of 3.75MW/cm2 did not trigger GRIIRA at a level that could have caused the11catastrophic thermal loading and physical damage seen before (quadratic scaling law). Photo-refraction appears to be the dominating effect here. A comparison with reported threshold intensities for photo-refraction of 2MW/cm2 for a congruent 5% MgO:PPLN sample [16] and >8MW/cm2 for a congruent 6% MgO:PPLN sample [14] (CW, green light, focused beams, no OPO operation) shows that the intensity of this experiment was on the same order of magnitude. On the other hand, damage thresholds vary largely in the literature based on the pump source parameters. Also, definitions of damage vary considerably in the published literature with some papers referring to damage as the onset of measurable changes in the refractive index, whilst others refer to damage as irreversible physical damage. Depending on the level of exposure, the effects of photo-refraction can be reversed by annealing the crystal for a few hours. However, the dark spot was still existent after 2h of annealing at 220°C and a recovery period of many days (without using the crystal in the OPO). Thus in this case, the damage appears to be irreversible suggesting not only optical, but also physical damage.B.2 Crystal performance under the influence of reduced average pump powerThis section refers to the observations made during the experiments of section 3.A.2, where a mechanical chopper in the pump beam reduced the average pump power.The experiments with a mechanically chopped pump beam were carried out in the next poled grating of the MgO:PPLN with a period of 6.9µm. The importance of this experiment was to isolate the effect of high peak power from the effect of high average power on the damage and to investigate their impacts. A maximum of ~1W of average pump power before the chopper was 10× reduced to ~0.1W (1:9 duty cycle) and then focused into the crystal. The peak intensity before and after the chopper was 7.5MW/cm2, since the pulses within the 0.67ms-long, 10% ‘transmit’ cycle were not affected by the chopping. Under these circumstances, i.e. with a true input average pump power of 0.1W, the OPO was operated without any permanent damage or dark spots observed. The 6ms-long chopper ‘block’ cycle was too short for a recovery of the GRIIRA effect, which has a time constant of ~20s [13], but the significantly reduced average power avoided the physical damage. The strong signal and idler output power fluctuations (Fig.6) indicated that some low-level photo-refraction was still present. Again, the 6ms ‘block’ cycle was not long enough to allow for a natural recovery of the photo-refractive effect, i.e. a complete diffusion of the free charge carriers, since the time constants for this process, even at elevated temperatures, are orders of magnitude larger. With the intensity of 7.5MW/cm2 being 2× higher than in the previous experiment, the damage process appears to require high average power and not just high intensity.C. Optimum operational regimeFor a more exact determination of the damage threshold, we carried out a systematic investigation starting from the situation as given in column 5 of Table 1 with 0.1W of average power as input to the crystal, where no damage was observed. The average power was kept constant and the peak intensity was successively increased. This independent control was achieved by using a half-waveplate and polarizing beamsplitter to increase the average power and hence the peak intensity followed by a mechanical chopper with wheels of decreasing duty cycle to only reduce the average power but not the peak intensity of the pulses within the ‘transmit’ cycle. After 1h of operation (signal and idler present) using the previously unused 6.8µm grating and a pump pulse intensity of ~11MW/cm2, the beam distortion and dark spot effect were observed, but no physical damage was generated. At an even higher intensity of ~17MW/cm2, physical damage occurred after only a few minutes in that same grating. Therefore, the peak intensity damage threshold can be pin-pointed to a range of around 7.5MW/cm2 to 11MW/cm2.12。

Lecture_01

UNIT OF STUDY OUTLINE
• • • • • CONTENTS Topic Guide in UoS (Blackboard) Course Text – Co-Op Bookshop Lectures, workshops and work outside contact hours Consultation: Mon 5-6pm, rm 445, Econ & Bus Guest lecture Connecting what we have learned in Corporate Finance about Capital Structure & Corporate Control to UNDERSTAND HOW VALUE IS CREATED IN M&A
– Group Project
• Workshop exercises (one week in computer lab • Practiing Blackboard and Web for efficiency • INTEREST IN TOPIC – SELF LEARNING
GROUP PROJECT
• Task 3 – Final group report due by 4:30pm Friday 28th May, 2010 – Submitted electronically and in hard copy • Task 4 – Each member within the group will need to complete a Group Assignment Self-Reflective Journal – The self reflection exercise will be marked and is worth 10% of your assignment grade – Students who do not submit this journal will receive a zero grade for this group assessment

新世纪大学英语综合教程1网课

新世纪大学英语综合教程1网课班级学号（如1班1号就是：0101） [填空题] *1. --- Did you go to the popular tourist attraction yesterday?--- Yes. After waiting for hours to get in, I found _______ too tired to finish the tour. [单选题] *A. itB. meC. itselfD. myself(正确答案)2. I don’t doubt ________ he will come in the coming year. [单选题] *A．whetherB．that(正确答案)C．ifD．so3. --- Have you made a plan to raise money to protect the animals in danger?--- Yes. Now we are thinking about how to _________ . [单选题] *A. pick it outB. carry it out(正确答案)C. find it outD. put it out4. --- It's raining heavily outside. May I push my bicycle into your house?--- Sure. But please put it _________ the wall so that it won't take up too much space. [单选题] *A. inB. onC. against(正确答案)D. over5. You _______ require others to deal with the problem like you. Everyone has his own way. [单选题] *A. mustn'tB. needn'tC. may notD. shouldn't(正确答案)6. ______ taking exercise is important, you'd better not exercise too close to bedtime. [单选题] *A. IfB. AsC. Though(正确答案)D. Unless7. --- I am very proud of the _________ China has made to fighting against COVID-19. --- A great country usually takes on its duty. [单选题] *A. advantageB. agreementC. contribution(正确答案)D. development8. --- Do you have any problems if you _________ this job?--- Well, I'm thinking about the working hours. [单选题] *A. offerB. are offered(正确答案)C. will offerD. will be offered9. --- Did Lisa leave a message? --- Yes. She wanted to know _________ this Sunday [单选题] *A. who you would go shoppingB. if you would go shopping with her(正确答案)C. that you will go shoppingD. when will you go shopping with her10．—As Laozi’s book says, a thousand-mile journey begins with the first ________. —Yes, let’s get started now! [单选题] *A．tryB．dayC．step(正确答案)D．started11．That’s a bad habit of learning. ________， it is never too late for you to get out of it. [单选题] *A．InsteadB．Anyway(正确答案)C．BesidesD．Moreover12．—Gary, I your room. I hope you can keep it as clean as it is now.—Promise! I’ll tidy it up every Saturday. [单选题] *A．cleanB．will cleanC．have cleaned(正确答案)D．was cleaning13．Nowadays, the citizens in Shanghai ________ to divide the waste from daily life into four different groups. [单选题] *A．requiredB．are required(正确答案)C．requireD．are requiring14．—Why don’t you like playing chess?—Playing chess is an activity ________ needs much patience. But I’m not patient at all. [单选题] *A．which(正确答案)B．whatC．whoD．where15.—We’ve discussed this many times. No jeans to the party!—Very well then, if you ________. But where’s my suit? [单选题] *A. suggestB. imagineC. agreeD. insist(正确答案)16. I love this city, ___________ in spring, even though I was not born here. [单选题] *A. certainlyB. speciallyC. especially(正确答案)D. properly17. -Mum, I want to watch the news about our school. Change the channel, please!-What a pity! It is eight o’clock now. It___________ for a while. [单选题] *A. has been over(正确答案)B. was overC. has finishedD. finished18.We still know little about the Moon ________ men have landed on it. [单选题] *A. ifB. sinceC. although(正确答案)D. because19. A great deal of my time is__________ with practicing playing the guitar. [单选题] *A. taken up(正确答案)B. made upC. put upD. set up20.—When shall we go on a picnic, Saturday or Sunday?—_________ is OK. I'm free the whole weekend. [单选题] *A. NeitherB. AllC. Either(正确答案)D. Both21.The Chinese language has become a bridge to___________ China___________ the rest of the world. [单选题] *A. connect.. to(正确答案)B. translate.. intoC. compare... withD. separate…from22. —I don’t mind giving you a detailed explanation of what happened that day. —You___________. I’m not asking you for it. [单选题] *A. can’tB. mustn’tC. needn’t(正确答案)D. couldn’t23.—Mary got the first prize in the writing competition after years of hard work.—_________. [单选题] *A. No pain, no gain(正确答案)B. A miss is as good as a mileC. Don't burn the candle at both endsD. A friend in need is a friend indeed24.—I think keeping dogs not make you feel lonely.—__________. Dogs sometimes bring a lot of trouble. [单选题] *A. Not exactly(正确答案)B. Take it easyC. I agree with youD. That's a good idea25.In order to send the donations to the hospital as soon as possible, thedrivers___________ stopped to eat or rest during the journey. [单选题] *A. nearlyB. hardly(正确答案)C. badlyD. mostly26. There are ___________teachers in our school, and ____________of them are women teachers. [单选题] *A. two hundreds; three fourthB. two hundred; three fourths(正确答案)C. two hundred; three forthsD. two hundred of; three fourths27. Some passengers were waiting at the bus stop___________ the whole roof(屋顶) fell down. [单选题] *A. whileB. when(正确答案)C. as soon asD. after28. ___________ great fun it is to go hiking in _____________weather! [单选题] *A. What, so fineB. How, such a fineC. What, such fine(正确答案)D. How, so fine29. ―It seems that your daughter shows an interest__________ playing the guitar.―Exactly. Her teacher says she has a gift _________music [单选题] *A. for; ofB. of; forC. in; ofD. in; for(正确答案)30. Although you failed four times, I still hope you can have________ try. [单选题] *A. the fifthB. a fifth(正确答案)C. the fourthD. a fourth31. --- Will Jim come to your son's birthday party tomorrow afternoon?--- He _________ come, but it depends on whether his work will be done by then. [单选题] *A. may(正确答案)B. shouldC. mustD. need32. --- Have you ever been to Shanghai?--- Of course. Actually, I _________ there for six years but now I live in Suzhou. [单选题] *A. worked(正确答案)B. was workingC. would workD. have worked33. Lots of people exercise every morning _________ bad weather stops them. [单选题] *A. ifB. unless(正确答案)C. untilD. since34. Because of the war, love and happiness were totally ______ from little Tom's childhood. [单选题] *A. separateB. absent(正确答案)C. extraD. blind35. Hobo will never know ______ they made a right choice at that moment. [单选题] *A. whatB. whenC. whileD. whether(正确答案)36. It's rude and impolite to ______ before others while everyone is queuing to buy tickets. [单选题] *A. take inB. cut in(正确答案)C. put inD. break in37. —Don’t you think Huawei company is _______ success?—Yes, I do. Huawei smartphones are popular among _______ public in China. [单选题] *A. the; aB. a; the(正确答案)C. a; aD. /; a38. He offered __________ valuable advice that __________ people disagreed. [单选题] *A such; a fewB such; few(正确答案)C. so; a fewD. so; few39. The way we thought of ________ the environment proved to be very useful. [单选题] *A. to protect(正确答案)B. protectingC. protectedD. protects40. --- When shall we hand in our book review on The Kite Runner?--- As soon as it _________ . [单选题] *A. completesB. is completed(正确答案)C. will completeD. will be completed41. By taking an online spoken English course, I find _________ much simpler to speak English. [单选题] *A. thisB. thatC. it(正确答案)D. one42. --- Will your cousin go to Guiyang for the summer holiday?--- In fact, he _________ Guiyang since he graduated. [单选题] *A. has gone toB. has been toC. has been in(正确答案)D. went to43. To avoid_______ ，we'd better________ the parents' meeting online. [单选题] *A. gather; holdB. gathering; hold(正确答案)C. gathering;to holdD. to gather; to hold44. He _______ for two years. We are still sad about his _______. [单选题] *A. died; deadB. died; deathC. has been dead; deadD. has been dead; death(正确答案)45. －_______ will the meeting last?－_______ they reach an agreement. [单选题] *A. How long; Not untilB. When; Not untilC. How long; Until(正确答案)D. When; Until46.She is such a careless girl that she has her wallet ______ . [单选题] *A. to stealB. stolen(正确答案)C. stealingD. stole47.—What do you think of the price of these computers?—They are not cheaper than ________at the other companies. [单选题] *A. itB. onesC. thatD. those(正确答案)48.The girl is ________ a singer ________ everyone in her hometown. [单选题] * A．well known as; forB．well-know as; toC．well known as; to(正确答案)D．best known for; for49．Lucy is organized and her room always looks _________ (整洁) than mine. [填空题] *空1答案：tidier50．Everyone _________ (除了) me has seen Hi, Mom, so I’ll go to see it today. [填空题] *空1答案：except51．I have made much more __________ (进步) in Physics this term. [填空题] *空1答案：progress52．Mr Jiang is pleased with the robot. It can ________ (满足) all his needs. [填空题] *空1答案：satisfy53. I will be happy if Sandy _________ (接受)my offer. [填空题] *空1答案：accepts54．Yao Ming scored 41 points in a game _________ (对抗) the Atlanta Hawks. [填空题] *空1答案：against55．He said he __________ (后悔) buying that book because his father had already bought one for him. [填空题] *空1答案：regretted56．The girl sitting behind me often worries a lot about her ________ (高度). [填空题] *空1答案：height57．—Excuse me, where is the railway station?—Go straight on, it’s just ________ (在……对面) Wanda Plaza. [填空题] *_________________________________(答案：opposite)58.Two ____ (九) of the students in our school suffer from stress. [填空题] *空1答案：ninths59. We live in the same building but my flat is three floors above _______________(她). [填空题] *空1答案：hers60.You can never imagine how much difficulty the pilot had ______________ (控制）the plane in the accident. [填空题] *空1答案：controlling61. The ______________（决定）you’ve made are completely right, I agree with you. [填空题] *空1答案：decisions62. Please write down the _______________（英雄）names on the paper right now. [填空题] *空1答案：heroes'63.Every year, _________ (百万) of people donate money to the Hope Project. [填空题] *空1答案：millions64．________ (相比) with those soldiers at the front, the danger I met is nothing. [填空题] *空1答案：Compared65．I’m surprised to find that the price of bread has ________ (上升) by 15% recently. [填空题] *空1答案：risen66．The idea of vaccination (接种疫苗) is now ________ (广泛地) accepted. [填空题] *空1答案：widely67．This kind of disease ___________ (传播) so quickly that it drew the government’s attention. [填空题] *空1答案：spread68. Though many basketball players are tall, one does not have to be tall to ________(成功) in NBA. [填空题] *_________________________________(答案：succeed)69.She is so________ (自豪的) of her son because he has won a prize in the English competition. [填空题] *_________________________________(答案：proud)70. When my father was young, he __________（宁愿选择）education to any other thing. [填空题] *_________________________________(答案：preferred)71. Helping others is one of the most ________ (宝贵的) things in the world. [填空题] *空1答案：valuable72. The __________ (生气) the parents are, the more scared the children will be. [填空题] *空1答案：angrier73. Many people speak highly of Hi, Mom! --- a new film ________ (导演) by Jia Ling. [填空题] *空1答案：directed74. I think one of the ________ (德国人) design of the new car is better than yours. [填空题] *空1答案：Germans'75. It gives me a sense of _______ (成就) when I make it to the end of a very long book. [填空题] *空1答案：achievement76. —How long has he been _____ (离开) from Sydney? [填空题] *_________________________________(答案：away)77. The girl's sweet voice caught several well-known _______ (音乐家) attention. [填空题] *空1答案：musicians'78. Finally they succeeded in ______ (解决) the problem after hard work. [填空题] *空1答案：solving79. We all think those soldiers' brave act is well worth _________(赞扬). [填空题] *_________________________________(答案：praising)80. The writer always ____ (建议) young people to be brave in the face of pains. [填空题] *空1答案：advises81. I think our Chinese teacher is the ______ (严格) of all the teachers in our school. [填空题] *空1答案：strictest82. --- This scientist is great enough to devote most of his lifetime to the medical research. --- That's why he was spoken h _______ of and presented with the national medal. [填空题] *_________________________________(答案：highly)83. --- Lucy's father's d ________ is really a big blow to her.--- Yes. Now she only has Mum. We should do something to cheer her up. [填空题] * _________________________________(答案：death)84.—We will succeed in the end u_______ we give up halfway.—Exactly. Let's try to make it. [填空题] *_________________________________(答案：unless)85. --- Working hard is important, but we should have some time for our hobbies to relax. --- I can't a ____ more. [填空题] *_________________________________(答案：agree)86. --- What is your r _____ for not doing your homework, Millie?--- I'm sorry, Mr. Wu! I forget it. [填空题] *_________________________________(答案：reason)87.Andrew is clever and hard-working. He often works out some problems verye__________. [填空题] *空1答案：asily88.The task is too difficult. Lucy has no c________ but to ask others for help. [填空题] *空1答案：hoice89.The managers of the big company have been used to d ____________with problems online. [填空题] *空1答案：ealing90.The artist is so c_____________ that he can make different changing pictures with sand. [填空题] *空1答案：reative91.Boys and girls, please teach y______________ the article we will learn tomorrow. [填空题] *空1答案：ourselves92. Don't care too much about others. What m_________ most is how you see yourself. [填空题] *空1答案：atters93. Andy's mother still looks young although she is already in her _________ .(四十）[填空题] *空1答案：forties94. ―In the past, I always m___________________ Lily for Lucy.―So did I. They looked really the same. [填空题] *_________________________________(答案：mistook)95．China has successfully helped over 90 million people out of poverty(贫困). We take p________ in our country! [填空题] *空1答案：ride96. ---May I talk to the sales manager?---Just a minute. I will put you t____________. [填空题] *_________________________________(答案：through)97．Mrs Green. No one is a___________ from school today. Everybody is here. [填空题] *空1答案：bsent98．Go down this street u___________ you come to the post office. [填空题] *空1答案：ntil99．—Were you late yesterday?—Yes. When I arrived at the cinema out of b________, the film had already been on for 10 minutes. [填空题] *_________________________________(答案：breath)100. --- Dustin, can you help me work out the math problem?--- Sorry, I'm an English teacher and it is really b ______ my ability. [填空题] *_________________________________(答案：beyond)。

1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。

• The fallacy of composition
– What is true for the individual is true for the group
• The mistake of ignoring the secondary effects
– Unintended consequences
Using Graphs and Formulas
• Graphs of Two Variables
Point on Graph Amount of Oil Used (Gallons per Month) Cost ($)
Monthly Cost of Oil for a Household
origin a b c d e
• Economists assume consumers will buy goods and services that will maximize their satisfaction. • Economists assume firms will act to maximize their profits.
– Decide on the assumptions to be used in developing the model. – Formulate a testable hypothesis. – Use economic data to test the hypothesis. – Revise the model if it fails to explain well the economic data. – Retain the revised model to help answer similar economic questions in the future.
Value in the second period - Value in the first period x 100 Value in the first period
• Formulas for the Areas of a Rectangle and a Triangle
– The formula for the area of a rectangle is base x height. The formula for the area of a triangle is ½ x base x height.
The Science of Economic Analysis
• Economic theory / model
– Simplification of economic reality – Important elements of the problem – Make predictions about the real world
Normative Versus Positive
• Positive economic statement
– Assertion about economic reality – Supported or rejected by evidence – True or false – ‘What is’
/gmklass/pos138/datadisplay/sБайду номын сангаасctions/goodch arts.htm
Using Graphs and Formulas
/gmklass/pos138/datadisplay/sections/goodch arts.htm
Change in value on the vertical axis ∆y Rise Slope = = = Change in the value on the horizontal axis ∆x Run
Using Graphs and Formulas
• Positive and Negative Relationships
– Other-things-constant
Understand the role of models in economic analysis
• An economic variable is something measurable that can have different values, such as the wages of software programmers. • A hypothesis in an economic model is a statement that may be correct or incorrect about an economic variable. An economic hypothesis is usually about a causal relationship; for example, “outsourcing leads to lower wages for software programmers.”
ECON 100: Introduction to Microeconomic Theory
Lecture 1
Yilan Xu
The Economic Problem
• Wants, desires: unlimited • Resources: scarce
Ex: Time, natural resources, labor effort, capital are limited
• Economics
– How people use scarce resources to satisfy unlimited wants
•2
Microeconomics and Macroeconomics
• Microeconomics is the study of how households and businesses make choices, how they interact in markets, and how the government attempts to influence their choices. • Macroeconomics is the study of the economy as a whole, including topics such as inflation, unemployment, and economic growth.
Using Graphs and Formulas
• Formula for a Percentage Change
– The formula for a percentage change between two variables for any two periods:
– Percentage change =
– bar graph – pie charts. – time-series graphs
Using Graphs and Formulas
/gmklass/pos138/datadisplay/sections/goodch arts.htm
Using Graphs and Formulas
Understand the role of models in economic analysis
• Models are based on making assumptions because models must be simplified to be useful. – Behavioral assumptions about the motives of consumers and firms.
•9
Using Graphs and Formulas
• Graphs simplify economic ideas and help make ideas more concrete. Economists and policymakers can use graphs to help solve real-world problems. • Graphs of One Variable
• Good theory
– Guide – Sort, save, understand information
•4
Understand the role of models in economic analysis
• Models are simplified versions of reality used to analyze real-world situations. To develop a model, economists generally follow five steps.
Using Graphs and Formulas
• Determining Cause and Effect
– Inferring cause and effect relationships by observing graphs can lead to incorrect conclusions. – One reason for this is that there may be an omitted variable that is not accounted for in the graph. – A related problem in determining cause and effect is reverse causality; this occurs when we conclude that changes in variable X cause changes in variable Y, when changes in variable Y cause changes in variable X.