郑景婷考研英语1420打印终极完整版

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Neural Network-based Correction and Interpolation of Encoder Signals for Precision Motion Control
Kok-Zuea Tang*, Kok-Kiong Tant , Tong-Heng Leet and Chek-Sing Teos *t@Department of Electrical and Computer Engineering
I. INTRODUCTION
In precision control, it is desirable to improve the resolution and accuracy of the overall control system. One way to achieve this aim is to improve the precision of the encoders used. However, the current state of the manufacturing technology of the encoders limits the achievable precision of encoders. Specifically, the scale grating on linear optical encoders can be manufactured to less than four micrometers in pitch, but clearly, further reduction in pitch will be greatly constrained by physical considerations. This implies an optical resolution of one micrometer can be currently achievable. Interpolation using soft techniques provides an interesting possibility to further improve on the encoder resolution, by processing the analog encoder signals online to derive the small intermediate positions. The error sources associated with positional information obtained this way can he classified under pitch and interpolation errors. Pitch errors arise mainly due t o scale manufacturing tolerances and mounting distortion. They can be compensated via the same prc+ cedures which are carried out for general geometrical error compensation. Interpolation errors, on the other hand, are associated with the accuracy of subdivision within a pitch. Ideal signals from encoders are a pair of sinusoids with a quadrature phase difference between them. Interpolation operates on the relative difference in the amplitudes and phases of these paired sinusoids. Therefore, interpolation errors will occur if the pairperiodic signals deviate from the ideal waveforms on which the interpolation computations are based. These

要不要报考辅导班？关于考研辅导班的研究介绍

要不要报考辅导班？关于考研辅导班的研究介绍关于考研辅导班下面说的这些都是建立在翻看论坛里面前辈们的帖子和各大考研结构2010免费动员班和宣传册的成果。

一、英语英语是考研里面最难的，但却是最没有必要报辅导班的，但是辅导班可以不上，课还是要听的，听新东方的有以下几个理由：1、考研英语每年变化不大，以前的解题思路技巧完全适用于最新的考试2、新东方的2009全套课程网上都有下载（基础班+强化班+冲刺班+各种单项）3、那些可下载的课程是专门为网络设计的，课件制作非常精细，效果非常好，而且都配发文本讲义，其他辅导班虽然也有录音下载但都是前辈们私录，效果参差不齐而且没有讲义教材不过这些只是次要的，新东方虽然强大，但他最多只能教你方法和思路，最关键的还是要靠自己下来练习，消化也就是说，不能把希望寄托于辅导班，辅导班只起辅助作用，不起决定作用二、数学我不考数学，但是因为前辈们的文章里面经常有介绍，所以顺带着看过，因为我不学，没有发言权，不过我对数学有一个感受就是数学辅导班的师资重合率很高也就是说，很多老师都在多家辅导班兼职，比如李永乐，我看了好几个辅导班的宣传册，都有他的名字，好奇搜索一下，貌似口碑也不错我的意思就是，数学似乎各个辅导班并没有明显的差距，但是因为不学，其他的我不敢多说三、政治政治是2010最纠结的一门课，因为换考试科目了，虽然万变不离其宗，但是很多东西是以前没有的，所以我感觉政治报班还是有必要的看了各个辅导班的宣传材料后，我感觉政治领域很混乱，老师很多不过我总结了一下，考研政治领域主要是两帮人，一个是人大的老师，特别是人大马克思主义学院，里面出来的老师太多了，另外一个就是西安交大，这个主要是以任汝芬为代表我仔细的看过论坛里面前辈们的经验，基本可以得出这样一个结论，任汝芬的书很好，但是讲课一般而人大的老师较为分散，也就是说不集中，可能这个老师擅长这门课那个老师又擅长那门课关于政治还要继续考察，不过好在政治的复习可以靠后一些，再考察一段时间再说四、总结还是那句话，这句话贯穿辅导班全程“不能把希望寄托于辅导班，辅导班只起辅助作用，不起决定作用，关键还是自己的努力”更不能相信辅导班能押题甚至漏题的鬼话另外辅导班现在都是商业化运作，宣传都是天花乱坠的，极具煽动性诱惑性，大家一定要淡定！淡定！全方位考察后再决定，浪费金钱事小，关键是浪费时间和精力另外还有一点，大家不能相信百度知道和百度贴吧，因为里面几乎全部是托，有正托也有反托，总之很混乱PS：发现两个无良考研机构，不过鉴于这篇帖子我是以一种客观的态度来写，这里就不明说了全国性考研辅导班概况评析1. 文都品牌实力：92--这是在考研辅导届子虚乌有的东西简评：1996年成立，办学11年，全国120个直属及加盟分校。

句句真研标静姐分数线考研英语语法

句句真研标静姐分数线考研英语语法Understanding the Syntax and Grammar of English Language for the Graduate English ExaminationIntroductionIn this document, we will delve into the intricacies of English syntax and grammar in preparation for the graduate English examination. We will explore key concepts such as sentence structure, parts of speech, verb tense, subject-verb agreement, and word order. Understanding these aspects of English language will not only help improve your writing and communication skills but also aid in achieving a high score on the examination. Let's begin our journey into the world of English language syntax and grammar.Sentence StructureEnglish sentences are typically structured in asubject-verb-object format. The subject is the entity performing the action, the verb is the action itself, and the object is the entity receiving the action. For example, in the sentence "Mary (subject) ate (verb) an apple (object)," Mary is the subject, ate is the verb, and apple is the object.Parts of SpeechThere are eight parts of speech in English: nouns, pronouns, verbs, adjectives, adverbs, prepositions, conjunctions, and interjections. Nouns are words that represent people, places, things, or ideas. Pronouns replace nouns in a sentence. Verbs express action or state of being. Adjectives describe nouns or pronouns. Adverbs modify verbs, adjectives, or other adverbs. Prepositions show the relationship between a noun or pronoun and other words in a sentence. Conjunctions connect words, phrases, or clauses. Interjections express emotion or sentiment.Verb TenseVerbs in English have different tenses to indicate when an action took place. The three primary verb tenses are past, present, and future. Each tense can be further subdivided into simple, continuous, perfect, and perfect continuous forms. For example, the simple past tense is used to describe actions that occurred in the past, such as "She walked to the store." The present continuous tense describes actions that are currently happening, as in "He is eating dinner."Subject-Verb AgreementSubject-verb agreement is essential to maintain grammatical correctness in a sentence. The verb in a sentence must agree with the subject in terms of number (singular or plural). Forexample, in the sentence "The cat (singular subject) is (singular verb) sleeping," the singular subject "cat" requires the singular verb "is." However, in the sentence "The cats (plural subject) are (plural verb) sleeping," the plural subject "cats" requires the plural verb "are."Word OrderIn English, word order plays a crucial role in conveying meaning. While the basic word order in English issubject-verb-object, there are variations based on the type of sentence (declarative, interrogative, imperative, or exclamatory) and the emphasis placed on certain words. For example, in a declarative sentence, the word order is subject-verb-object, as in "She (subject) plays (verb) the piano (object)." In an interrogative sentence, the word order is often inverted, as in "Does she (auxiliary verb) play (verb) the piano (object)?"ConclusionMastering the syntax and grammar of English language is essential for success in the graduate English examination. By understanding sentence structure, parts of speech, verb tense, subject-verb agreement, and word order, you can improve your writing skills and communication abilities. Remember to practice regularly and seek feedback to enhance your proficiency inEnglish language. Good luck with your preparations for the examination!。

(完整word版)研究生公共英语教材阅读B第3、4、10、11、14课文原文及翻译

Unite 3 Doctor's Dilemma: Treat or Let Die？Abigail Trafford1。

Medical advances in wonder drugs，daring surgical procedures，radiation therapies，and intensive—care units have brought new life to thousands of people. Yet to many of them, modern medicine has become a double-edged sword。

2。

Doctor’s power to treat with an array of space—age techniques has outstripped the body's capacity to heal. More medical problems can be treated，but for many patients，there is little hope of recovery. Even the fundamental distinction between life and death has been blurred。

3。

Many Americans are caught in medical limbo, as was the South Korean boxer Duk Koo Kim，who was kept alive by artificial means after he had been knocked unconscious in a fight and his brain ceased to function。

With the permission of his family，doctors in Las Vegas disconnected the life-support machines and death quickly followed。

AADE-14-FTCE-05

Copyright 2014, AADEThis paper was prepared for presentation at the 2014AADE Fluids Technical Conference and Exhibition held at the Hilton Houston North Hotel, Houston, Texas, April 15-16, 2014. This conference was sponsored by the American Association of Drilling Engineers. The information presented in this paper does not reflect any position, claim or endorsement made or implied by the American Association of Drilling Engineers, their officers or members. Questions concerning the content of this paper should be directed to the individual(s) listed as author(s) of this work.AbstractDuring cementing operation, it is critical to determine the flowing of cement slurry between the casing and formation, depth of the circulation losses and fluid loss, setting of cement in place and performance of the cement after hardening. Recent case studies on cementing failures have clearly identified some of these issues that resulted in various types of delays in the cementing operations. At present there is no technology available to monitor cementing operations in real time from the time of placement through the borehole service life. Also, there is no reliable method to determine the length of the competent cement supporting the casing.In this study oil well cement with better sensing properties, henceforth called smart cement, was used to verify that its behavior can be monitored at various stages of construction and during its service life. A series of experiments evaluated the smart well cement behavior with and without up to 0.3% sodium metasilicate (SMS) to determine the sensitivity of the electrical resistivity of cement from curing to hardened state was investigated. The test results showed that SMS reduced the electrical resistivity of the water and cement slurries based on the amount. The SMS up to 0.3% also affected the rheological properties, setting characteristics, and the piezoresistive properties of the smart cement. In a 24-hour period the maximum change in the electrical resistivity (RI24) for the cement without SMS (0.4 water-to-cement ratio) was 175%. The RI24for the cement with SMS varied with the amount of SMS. Addition of 0.2% SMS had a minimal effect on the compressive strength. The smart cement was piezoresistive with the addition of SMS but the sensitivity was decreased.IntroductionAs deepwater exploration and production of oil and gas expands around the world, there are unique challenges in well construction beginning at the seafloor. Recent case studies on cementing failures have clearly identified several issues that resulted in various types of delays in the cementing operations. Also preventing the loss of fluids to the formations and proper well cementing have become critical issues in well construction to ensure wellbore integrity because of varying down hole conditions (Labibzadeh et al., 2010; Eoff et al., 2009; Ravi et al,. 2007; Gill et al., 2005; Fuller et al., 2002). Moreover, the environmental friendliness of the cements is a critical issue that is becoming increasingly important (Dom et al., 2007; Thaemlitz et al., 1999; Durand et al., 1995). Lack of cement returns may compromise the casing support, and excess cement returns can cause problems with flow and control lines (Ravi et al. 2007; Gill et al. 2005; Fuller et al. 2002). Hence there is a need for monitoring the cementing operation in real time. At present there is no technology available to monitor the cementing operation real time from the time of placement through the entire service life of the borehole. Also, there is no reliable method to determine the length of the competent cement supporting the casing.In characterize the behavior of cementitious materials several methods such as X-ray diffraction, calorimetric analysis, scanning electron microscopy, and ultrasonic methods have been in used. Electrical resistivity measurement has been applied by many researches on concrete and other cementing applications (Taylor and Arulanandan, 1974; McCarter et al., 1998and 2006; Vipulanandan et al. 2006), but there are no reports in the literature of electrical resistivity measurements for characterizing oilwell cement. Electrical response characteristics measurement has appropriate sensitivity in monitoring the characteristics of cementitious materials (McCarter et al., 1998). The advantages in using this technique include its accuracy, ease of testing and procedures, and nondestructive characteristics (Vipulanandan et al., 2004-2013). Additionally, this method can be used for monitoring the long term behavior of cement in practice.Electrical resistivity of cement is affected by a number of factors, such as pore structure (continuity and tortuosity), pore solution composition, cementitious content, water-cement (w/c) ratio, moisture content, and temperature (Polder et al., 2001). Moreover, electrical resistivity of cement is dramatically affected by admixtures, due to the resistivity contrast between cement and the admixture substances. Vipulanandan et al. (2004, 2006-2013) have studied the change in electrical resistivity with applied stress, referred to as piezoresistive behavior of modified cementitious and polymer composites. The studies showed that the changes inAADE-14-FTCE-05Characterizing Smart Cement with Sodium Metasilicate for Real Time Monitoring of Ultra-Deepwater Oil Well Cementing ApplicationsCumaraswamy Vipulanandan and Kausar Ali, CIGMAT-University of Houston, Guido Narvaez, Baker Hughes; Donald A.Richardson and James M. Pappas, Research Partnership to Secure Energy for America2 C. Vipulanandan, K. Ali, G. Narvvaez, D. Richardson and J. Pappas AADE-14-FTCE-05resistivity with the applied stress were 30 to 50 times higher than the strain in the materials. Hence, the change in resistivity has the potential to be used to determine the integrity of the materials.Sodium metasilicate (SMS)From the initial use in the late 1800’s sodium silicate based compounds have been used in a number of applications including cementing, grouting, emulsifying, and in cleaning agents. Of the various forms of sodium silicate based compounds, sodium meta silicates (anhydrous) have been used in oil and gas industry related applications. Because of its emulsification and interfacial tension reduction characteristics, SMS has been used in alkaline flooding, a chemical recovery method to recover oil from various types of geological formations and sand (Larrondo et al. 1985).Based on the chemical composition of sodium metasilicate (Na2SiO3), it can react with the cement hydration products, forming various types of calcium silicate hydration gels. Fasesan et al. (2005) investigated the use of 0.5% of sodium metasilicate (by weight of cement) in 50:50 class H cement slurry to replace the 2% bentonite. The study showed that the sodium metasilicate was effective in controlling free water and fluid loss. In many parts of the world, severe lost circulation and weak formations with low fracture characteristics are common. These situations require the use of low-density cement systems that reduce the hydrostatic pressure of the fluid column during the cement placement process. Hence lightweight additives (also known as extenders) are used to reduce the weight of the slurry. Malyshev et al. (2013) used SMS as the extender for a lightweight cement system of density 1500 kg/m3 (12.6 ppg). Hence SMS has multifunctional ability to modify the oil well cement.ObjectivesThe overall objective of the study was to determine the effect of sodium metasilicate on the behavior of smart oil well cement. The specific objectives are as follows:(i) Effect of SMS on the rheological, curing, and electricalproperties of smart oil well cement.(ii) Effect of SMS on the piezoresistive behavior of hardened smart oil well cement.Materials and MethodsMaterialsSmart CementCommercially available oil well cement (Class H cement) was modified with additives to make it a piezoresistive material.Sodium MetasilicateSodium metasilicate, also known as disodium metasilicate, used in this study is a white, odorless, granular anhydrous powder. Based on the data sheet provided by the chemical manufacturer, it has a molecular weight of 122 g/mol, pH of12.5 at 10 g/l at 20 °C (68 °F), melting point of1,090 °C (1,994 °F), density of 2.61 g/cm3 at 20 °C (68 °F), and water solubility of 350 g/L at 20 °C (68 °F).MethodsSodium metasilicate (SMS) solutionThe samples were prepared by mixing selected amount of SMS powder (by weight of water) in water at room temperature. The mixture was blended using a table top blender and the pH was monitored at the end of mixing. Up to 5% SMS solution was prepared to characterize the electrical resistivity properties. Water with and without SMS was used to prepare the cement specimens.Cement MixtureThe samples were prepared according to the API standards. Smart cement with a cement-to-water ratio of 0.4 was used in this study. Two series of cement slurries were prepared with and without selected amount of SMS (0.2%). Cement Specimen PreparationAfter mixing, specimens were prepared using cylindrical molds with a diameter of 2 inches and a height of 4 inches. Two conductive wires were placed in all of the molds which were 5 cm apart. All specimens were capped to minimize moisture loss and were cured up to the day of testing for the piezoresisitivity under compressive loading. Rheological TestsRheological properties determine the ability of cement to be pumped. The rheology tests were performed by utilizing a rotational viscometer at room pressure and temperature at rpms ranging from 3 to 600, and related shear stresses were recorded. The viscometers were calibrated using several standard solutions.Electrical ResistivitySMS SolutionA commercially available conductivity probe was used to measure the conductivity (inverse of resistivity) of the fluids. The resistivity measuring range was from 0.1 Ω.mto10,000Ω.m.Cemen tBased on the results of past studies, electrical resistivity was selected as a monitoring parameter to quantify the performance of modified cement during the curing and hardening process (Vipulanandan et al.2004-2013). Electrical resistivity of the slurries was measured using an API standard resistivity meter. Further, electrical resistance was measured using an inductance –capacitance - resistance (LCR) meter during the curing time. To minimize the contact resistances, the resistance was measured at 300 kHz using the two-wireAADE-14-FTCE-05Characterizing Smart Cement with Sodium Metasilicate for Real Time Monitoring of Oil Well Cement 3method (Vipulanandan et al., 2013). The principle of measuring the resistance is shown in Figure1. Each specimen was calibrated to obtain the electrical resistivity (ρ) from the measured electrical resistance (R) based on the Eqn. (1).ρ = RA/L = R/(L/A) = R/K (1)where L is the distance between the wires, A is the cross-sectional area through which the current is flowing, and L/A is called the geometry factor K. Where parameter K=L/A, the ratio of the cross-sectional area and the length of the material is defined for a particular set-up. If we know the resistivity and the resistance of the material then from the relationship in Eqn. (1) we can determine the parameter K. The resistivity of each cement slurry was determined using the API resistivity meter. Figure 2 shows K values determine for four different cement slurries such as cement slurry with and without Sodium Meta-silicate (SMS). After about 5 hours (300 min), the K value stabilized and it was used to determine the resistivity of the hardened cement specimens. Compressive Strength Tests.Compressive strength of cement determines the ability of cement to stabilize casing in the wellbore. The cylindrical specimen was capped and tested at a predetermined controlled displacement rate. Compression tests were performed on cement samples after 2 and 7 days of curing using a hydraulic compression machine.Piezoresistivity Tests.Piezoresisitivity describes the change in electrical resistivity of a material under pressure. Since oil well cement serves as a pressure-bearing part of wells in real applications, the piezoresistivity of smart cement with and without SMS was investigated under compressive loading. During each compression test, electrical resistance was measured in the stress axis. To eliminate the polarization effect, alternating current (AC) resistance measurements were made using a LCR meter at a frequency of 300 KHz. Furthermore, changes in resistivity were related to the applied stress.Results and DiscussionsResultsThe average unit weight of the cement slurry was 121. 5 pcf.SMS SolutionpHAddition of SMS to the water increased the pH as shown in Figure 3. With the addition of 0.1% SMS, the water pH increased from 7.7 to 11.8, a 50% change in the pH. With the addition of 0.3% SMS the pH was 12.4.ResistivityThe resistivity of sodium metasilicate solution was determined with the conductivity probe. SMS solution was very sensitive to electrical resistivity. The resistivity of water decreased from 21Ω.m to 4.15 Ω.m with an addition of only 0.1% SMS (Figure 4), 80% reduction in resistivity. The addition of more SMS further reduced the resistivity of the solution. The following relationship is proposed based on the experimental results:ρ = ρo– S/(E +DS) (2)where:ρ = resistivity of the sodium metasilicate solutionρo = resistivity of tap water without sodium metasilicate(21 Ω.m)S = Concentration of sodium metasilicate (% byweight)Parameters E and D are model parameters: parameter E represent the initial rate of change and parameter D determines the ultimate resistivity. Experimental results matched very well with the proposed model with a coefficient of determination (R2) of 0.98, and parameters E and D were found as 0.0016/Ω.m and 0.047/Ω.m, respectively. Rheological propertiesGel StrengthFor the smart cement, after 10 seconds gel strength was 12 lb/100 ft2, and after 10 minutes gel strength was 14 lb/100 ft2.With the addition of 0.2% SMS to the cement the 10-second gel strength was 15 lb/100 ft2and the 10-minute gel strength was 17 lb/100 ft2. Hence, addition of 0.2 SMS increased the 10-second gel strength by 25% and the 10-minute gel strength by 21%.Effect of SMSIt was evident from the rheological tests on cement slurries with and without 0.2% SMS that the addition of SMS negatively affects the shear-thinning behavior of cement. Addition of SMS increased the viscous behavior of the cement. For instance, the viscosity of cement without SMS at a shear strain rate of 100 (1/sec) was 146 cP. At the same shear strain rate the 0.2 percent SMS sample had viscosity of 225 cP, a 54% increase in viscosity.ModelingDue to the shear-thinning behavior of the cement slurries the Bingham plastic model was not an accurate model to estimate the shear strain rate – shear stress relationship. To predict the shear strain rate - shear stress relationship, the Herschel-Bulkley model (Eqn.3) and hyperbolic model (Eqn.4) were used to predict the experimental data.The Herschel–Bulkley (H-B) model follows:τ = τo+ k γn (3)where:τ= shear stressγ= shear rateτo= yield stressk and n are model parameters.From the smart cement, the k and n were found to be4 C. Vipulanandan, K. Ali, G. Narvvaez, D. Richardson and J. Pappas AADE-14-FTCE-051.09 and 0.78, respectively (Figure 5). The coefficient of determination (R2) was 0.97. The yield stress was found as 1.87 lb/100 ft2.For the cement slurry with 0.2% sodium meta-silicate the k and n (for Herschel–Bulkley model)were found to be 0.61 and 0.88, respectively (Figure 6). The coefficient of correlation was 0.99. The yield stress was 13.8 lb/100 ft2, a notable increase in the yield stress with the addition of 0.2% SMS.The hyperbolic model is as follows:τ= τo + γ/(A+Bγ) (4)where.τ= shear stressτo= yield stressA andB are model parameters.Here for the smart cement parameters A and B were found as 2.83(Pa.sec)-1and 0.001Pa-1,respectively, and the coefficient of determination (R2) was 0.97. The yield stress was 5.01 lb/100 ft2. The apparent viscosity at 600 RPM was 106 cP.For the smart cement with 0.2 SMS, the hyperbolic model parameters A and B were found as3.21(Pa.sec)-1and 0.0004Pa-1,respectively, and the coefficient of determination (R2) was found to be 0.99. The yield stress was17.4lb/100 ft2.With the addition of 0.2% SMS the apparent viscosity at 600 RPM was 136 cP, a 28% increase.Fluid LossFor the smart cement the total fluid loss was 137 cc. Smart cement (w/c ratio of 0.4) with the addition of 0.2% SMS had a fluid loss of 145 cc (Figure 7), hence a 6% increase in the fluid loss.Electrical ResistivityInitial ResistivityThe electrical resistivity of the cement slurry with and without SMS was determined. The initial resistivity of the smart cement slurry was 0.97 Ω.m, and it decreased with the addition of sodium metasilicate, as shown in Figure8. With the addition of 0.1% SMS the resistivity decreased to 0.92 Ω.m, a 5% reduction. With the addition of 0.2% and 0.3%SMS the resistivity were 0.9 Ω.m and 0.88 Ω.m. Hence the resistivity was sensitive to the concentration of SMS in the cement. Resistivity during Curing ProcessElectrical resistivity could be used as a fingerprint of the curing process. Figure 9 illustrates the change in electrical resistivity (ρ) during curing time for smart cement with and without SMS. It was observed that the curves of the different samples, with and without SMS, follow a similar trend with time. The electrical resistivity dropped to a minimum value, and then gradually increased with time. After initially mixing cement with water, resistivity decreased to a minimum value (ρmin), and the corresponding time to reach the minimum resistivity was t min. The decrease in resistivity immediately after mixing was due to dissolution of soluble ions from the cement particles after cement was mixed with water, and the dissolving process of the ions caused the resistivity decrease during early periods. The term t min can be used as an index of speed of chemical reactions and cement set times. With the formation of resistive solid hydration products that block the conduction path, resistivity increased sharply with curing time. The following increase in electrical resistivity was caused by the formation of a large amount of hydration products in the cement matrix. Finally, a relatively stable increasing trend was reached by the ion diffusion control of hydration process. Resistivity increased steadily up to 24 hours and reached a value of ρ24. Change in electrical resistivity with respect to minimum resistivity quantifies the formation of solid hydration products, which leads to the strength development in the curing cement. Therefore, by tracking the change in resistivity of oil well cement, a clear understanding of the hydration process and strength development can be obtained. Hence the Resistivity Index at 24 hours (RI24) is defined as the maximum change in resistivity in 24 hours to reflect the changes in resistivity.Variations in electrical resistivity with time for samples with different amounts of SMS are summarized in Table 1. Increasing SMS content decreased the minimum resistivity of cement (ρmin). This is another indicator of the increased chemical reaction between the cement and SMS. With 0.2 percent SMS the minimum resistivity of cement decreased from 0.81 Ω.m to 0.75 Ω.m,a 7.5% percent decrease. Also, addition of SMS increased both the t min, and the rate of change in resistivity. RI(24)for the smart cement was 175 percent (Table 1). With the addition of SMS, RI(24) varied from 178 to 196 (%). In general, higher change in electrical resistivity (ρ24–ρmin) indicates that increased hydration products are developed in the hydrating cement system.Compressive StrengthEffect of SMSThe compressive strength of smart cement without any SMS was 1.0 ksi and 2.5 ksi after 2 days and 7 days of curing, respectively. As shown in Figs. 10 and 11, the addition of 0.2% SMS did not affect the compressive strength of cement. PiezoresistivityThe piezoresistive behavior (compressive stress versus change in resistivity) of cement with and without SMS is shown in Figs. 10 and 11 after 2 days and 7 days curing, respectively. Electrical resistivity was sensitive to compressive stress. Figures 10 and 11 show that electrical resistivity increased during compressive loading. Addition of SMS reduced the piezoresistive response of smart cement. After two days of curing the smart cement failed at a resistivity change of 550 percent, while the 0.2 percent SMS added cement failed at a resistivity change of 150 percent. After seven days of curing the smart cement failed at a resistivity change of 800 percent, while the 0.2 percent SMS added cement failed at a resistivity change of 200 percent. The failure strain is 0.25 percent, and hence the change in the resistivity of cement with 0.2 percent of SMS was 800 times higher than the strain.AADE-14-FTCE-05Characterizing Smart Cement with Sodium Metasilicate for Real Time Monitoring of Oil Well Cement 5ConclusionsBased on this experimental and analytical study on smart cement with the addition of sodium metasilicate (SMS), the following conclusions are advanced:1)Addition of 0.1% SMS increased the pH and reducedthe resistivity of water by 50% and 80%,respectively. The change in resistivity of water withthe addition of SMS has been modeled.2)Addition of 0.2% SMS increased both the 10-secondand 10-minute gel strength by over 20%.3)Addition of 0.2% SMS increased the yield strength,viscosity, and fluid loss. Shear stress and shear strainrate relationships have been modeled.4)Electrical resistivity developments with hydrationtime of the cement with different amounts of SMSfollow a similar pattern: they first drop to a minimumpoint and then gradually increase with time. Theminimum resistivity decreased, and the time toachieve minimum resistivity (rate of change)increased with the addition of increasing SMS. Theresistivity index (RI(24)) of the cement with andwithout SMS were comparable.5)The smart cement showed piezoresistive behavior.Addition of SMS reduced the piezoresistive behaviorof the smart cement. Addition of 0.2% SMS did notaffect the compressive strength of the smart cement. AcknowledgementsThis study was supported by the Center for Innovative Grouting Materials and Technology (CIGMAT) at the University of Houston, Texas. Funding for the project (Project No. 10121-4501-01) is provided through the “Ultra-Deepwater and Unconventional Natural Gas and Other Petroleum Resources Research and Development Program” authorized by the Energy Policy Act of 2005. This program—funded from lease bonuses and royalties paid by industry to produce oil and gas on federal lands—is designed to assess and mitigate risk enhancing the environmental sustainability of oil and gas exploration and production activities. RPSEA is under contract with the U.S. Department of Energy’s National Energy Technology Laboratory to administer three areas of research. RPSEA is a 501(c) (3) nonprofit consortium with more than 180 members, including 24 of the nation's premier research universities, five national laboratories, other major research institutions, large and small energy producers and energy consumers. The mission of RPSEA, headquartered in Sugar Land, Texas, is to provide a stewardship role in ensuring the focused research, development and deployment of safe and environmentally responsible technology that can effectively deliver hydrocarbons from domestic resources to the citizens of theUnited States. Additional information can be found at .References1.API Recommended Practice 10B (1997),Recommended Practice for Testing Well CementsExploration and Production Department, 22nd Edition. 2.API Recommended Practice 65 (2002) CementingShallow Water Flow Zones in Deepwater Wells.3.Banthia, N. and Dubeau, S. 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(完整word版)新视角研究生英语读说写1(1-6单元习题答案)(word文档良心出品).docx

1.The country is heavily dependent on its oil exports.A. reliant onB. complaint withC. yielding toD.attached to2.An alternative approach is to define words according to the sentence contexts in which they occur.A. outlineB. explainC. specifyD. term3. A second hospital has been accused of mixing up a baby’s name tag , making the mother fear she had the wrong child.A. codeB. paperC. boardD. label4.The director will have to shift his roles and expectations when he’s asked by the rest of the board to answer criticism of company performance.A. moveB. stintC. alterD. transit5.Japanese computer makers are turning to scientists overseas to help them develop software and applications for massively parallel supercomputers.A. heavilyB. immenselyC. solidlyD. ponderously6.There is also evidence that younger people expect to transfer the sourceof their main emotional support to their spouse when they marry.A. move ... toB. subtract ... fromC. distract ... fromD. deflect ... to7.Psychometric tests which attempt to measure students ’ ability to use the library have been developed and made use of primarily in the USA.A. arbitrateB. assessC. calculateD. reckon8.Consequently, the neighborhood they live in, the interests they have, the lifestyle of their friends and colleagues, will necessarily determine whatreality is for the child.A. residential pathB. residential streetC.residential districtD. residential part9.The aim is to help participants identify their own learning needs in this area and then to suggest ways in which they can increase their knowledge.A. affirmB. confirmC. assumeD. recognize10. As we shall see later, they have been one of the factors that have helped to tip the economic balance firmly against the nuclear option.A. tiltB. inclineC. slideD. slant1.Don’t interrupt him. He is now working seriously on his dissertation that is due at the end of this semester.A. buckling down toB. buckling underC. buckling up withD. buckling to2.He has a bad temper and always falls into a fury for the slightest reason, which makes him extremely unwelcome among all the friends.A. sadnessB. depressionC. an extreme angerD. great disappointment3.Through reading the novel, the students realized that the hunchback’s hideous appearance could not conceal his noble characters.A. spectacularB. ugly and unpleasantC. impressiveD.striking and terrible4.When the World War II broke out and the area was bombed severely,many city dwellers had to move to the sticks and led a totally different life.A. small townsB. country areasC. surroundingsD. neighborhoods5.In the general conference, his coarse speaking tone irritated the delegate from the neighboring country and then everyone was involved in a fierce debate.A. ironicB. sarcasticC. angryD. rude6.The police had to keep track of all the actions of the suspects in order to identify the real criminal.A. be informed aboutB. be contacted withC. follow up withD.take notice about7.Confronted with all these evidences and the witnesses, the drunk driver conceded that it was he who caused the fatality of the 3victims in the traffic accident.A. surrenderB. grandC. admitD. yield8.When famine and drought became more severe, the president said he couldnot size up the whole situation and take any action unless he had receiveda complete report.A. bring upB. come up withC. make upD. make a judgment about9.Gaping at the TV screen and watching the fire and smoke,the whole world was startled and could not believe the World Trade Center turned into ruins.A. LookingB. StaringC. GlancingD. Watching10. When thousands of bodies, including those of women and children,were discovered in the forest,everyone and all the media took the same side, criticizing the monstrous mass murder with full bullets.A. tremendousB. incidentalC. famousD. evil读说写 1 第 3 单元1.With a(n) __________ network of committees, sports clubs and societies, each student is encouraged to play a full part in this aspect of student life.A. thrivingB. encouragingC. excitingD. succeeding2.They may pick up ideas almost at random from skimming journals,ideas that may __________ new trains of thought or fruitful new cross-connections.A. steerB. pilotC. sparkD. lead3.Being a good listener is not only useful because you will hear what others miss, but you will find that people will tell you things that they __________ others.A. shield onB. shield fromC. shield inD. shield out4.What right did he have to come back into her life like this,trying to __________ it into small pieces that couldn ’t be put back together for a second time?A. crashB. crushC. shatterD. explode5.In many areas local services were provided by numerous different authorities, which often gave rise to __________ co-ordination problems.A. acuteB. accurateC. accusativeD. alternative6.The awful truth that he was suffering from lung cancer__________him, though his family members tried very hard to keep the secret.A. came uponB. dawned onC. fell toD. went for7.I suppose yoga enthusiasts would find it painless, but for most of us an hour spent in this position was a(n)__________.A. trialB. testC. examD. ordeal8.But rules that strengthen banks in good times can__________them in recessions.A. crippleB. reduceC. slashD. decrease9.There are few more __________ places on earth than the plains surroundinga volcano in the aftermath of its eruption.A. fertileB. unproblematicC. barrenD. unprofitable10. The minds of many of these young offenders appear to have been __________ by greed and indifference to violence.A. retardedB. numbedC. idledD. fooled读说写 1 第 4 单元1.Her reputation suffered a _________ blow as the result of the scandal.A. mortalB. shamefulC. humiliatingD. disgraceful2.In explaining this situation, it might be possible to point to sources _________ to the nation: its culture,mentality, religions, or geography.A. inheritedB. hereditaryC. inherentD. heritable3.His ________ difficulties may make it impossible for him to recognize you and his family.A. perceptualB. appreciableC. understandableD. recognizable4.He had never previously thought of himself as________or even as particularly materialistic.A. inquisitiveB. interactiveC. positiveD. acquisitive5.Like a dreamer, the young artist is absorbed in________of something outside himself and does not identify with it.A. illusionB. contemplationC. conceptionD. fantasy6.The club, where I am staying, releases forgotten gusts of memory,like those lilies which only________ their sweet perfume at night.A. exhaleB. inhaleC. relaxD. relieve7.If it is a technique which works for you then, use it ________.A. by all meansB. by no meansC. in one wayD. by the way8. You would ________ some responsibility immediately for particular areas and additional responsibilities are available to those with the ability andenthusiasm to undertake.A. bear onB. take onC. carry onD. hold on9. This raises the question whether the education of children in rural communities is prejudiced by the________ of a curriculum devised for urban conditions.A. publicationB. compulsionC. computationD. imposition10. The weak point in the school is due to the_________of parents who remove their sons from the school at too early an age.A. follyB. prudenceC. crazinessD. madness读说写 1 第 6 单元1.Even though the Duke was convicted of treason,most of the parliament members still supported him and his book was very popular among the publicA. betrayal of one’s countryB. surrender to the enemyC.hurt to people ’s feelingD. control of others2.This method may seem unorthodox , but it has been proved to be very efficient.A. fitfulB. accidentalC. irregularD. unconventional3.Many people settle down in urban areas instead of the countryside,since it is not time to take a sheer rest and they need to work in cities.A. comfortableB. completeC. relaxingD. permanent4.His voice began to falter at the mention of his sufferings in the old days.A. hesitateB. stutterC. decreaseD. shake5.Politically, Wisconsin is a bit of a maverick, and this nature was firmly established by 1848 when it became a state.A. dissenterB. proponentC. opponentD. extremist6.For over 30 years, Singapore has grown from a poor country with hardlyany resources to an affluent,modern and developed nation.A. abundantB. influentC. wealthyD. stimulant7.The doctor told the single father that his son needed to be coddled after the tuberculosis.A. isolated from othersB. treated with great careC. accompanied by othersD. cured with skill8.As a long-term fancier of the classical music, he spent a lot of money in watching live music concertsA. toastB. collaboratorC. shamblesD. zealot9. The architect said that his countrymen hadn’t learned to cherish the old, and they were too quick to tear old buildings down.A. preferB. treasureC. decorateD. renew10. The proud lady wondered how to lower her pride to approach the girl she had been so scornful of.A. hatefulB. convictedC. contemptuousD. doubtful。

Generation

of anOptimized Code ThecorrectnessGenerationTorb enPoort LangeComputer Science Departmen tyAarh usUniv ersitNovember1992Abstractprogramming language w itha lazy standard s e-Fora functionalby meansofabstract in terpre-mantics,we deﬂnea strictnessanalysisanalysiswe are able ing theinformationfromthestrictnesswhic h a voids dela y ing the ev aluation of the todeﬂnea co degenerationonding function argumen ttoan application,pro vided that thecorrespis strict.To sho w thecorrectnesswe will a dopt theoftheco de generation,and deﬂne a la yerofpredicateswhic h framew orkoflogical relationsis correct withresp e ct to ﬂnally w ill ensure that theco de generationthestandard s eman tics.1In tro ductionprogramming l anguage oneoften co defor a lazy functionalWhen generatingisin terested ingetting themoste–cien t co de,that isa voiding e xp ensiv eofa function f toan instructions.Consider a san example theapplicationargumen t x.If we do notkno w whether theargumen t will be usedby f, we m ust enclose the co defor x with a delay closure(also c alled thunk),th ussho ws dela y ing the ev aluation of x un til n eeded by f.Howev er,if ananalysis1that the argumen t so oner orlater will b eev aluated,wemigh taswell e v aluate it before calling the function f ,sothat wecana void the generation of a dela y closure atall.The information needed canbe obtained froma strictness analysis [1,6,11],whic h wewill d e ﬂnefor the language.The co degenerationtobede ﬂnedwill then usethis information toimpro v e theco de.To pro vethe correctnessof the co degeneration,wede ﬂnea standard seman-tics t ocapture t hemeaning ofexpressions.W e will thende ﬂne a la yerof admissible predicates that ensure t hat thestrictness analysis is correct and that theco degenerated beha vesasexp ected.Section 2will in tro d uceourprogramming language,Section 3de ﬂnesthe in terpretations,Section 4describ estheframew orkfor correctness,Section 5pro vesthecorrectness ofthestrictness analysis and Section 6pro vesthe correctness oftheco de generation.Finally ,Section 7concludes withsome references torelated work.Thispap eris an extended a bstract ofm y M.Sc.-thesis [13],whic h is based on thework[16]and[18]by HanneRiis Nielson andFlemming Nielson.Familiarit y with basic d omain theoretic asp ects (lattices,partial orders,c hains)isassumed,aswell aselemen t ary concepts fromthelam bda calculus and combinatory logic.2The LanguageThe functional language w ill c onsist ofa traditional t yped lam bda calculus toexpress en tities ofcompile-time anda t ypedcombinatory logic toexpress en tities ofrun-time.Underlining will b e used todenote run-time objects.Example The expression e oft ype t 1!t 2willb e a compile-time function from t 1to t 2,whereas e 0oft ype t 01!t02will b e a run-time function from t 01to t 02.When generatingco dewe will c onsider expressions ofthelatter t ype.¥The t ypesare de ﬂnedast ::=A i j t £t j t !t j A i j t £t j t !t 2where A i are someground t ypes,e.g.Bo ol and In t .The syn taxofexpressions ise ::=x i [t ]jf i [t ]jh e;e ij fst e j snde j ‚x i [t ]:e j e (e )jﬂx [t ]e j if e thene el see j F i [t ]j Id [t ]j 2[t ](e ;e )Tupl e [t ](e ;e )j Fst [t ]j Snd [t ]j C ond [t ](e ;e;e )jAppl y [t ]j C ur r y [t ]e j Fix [t ]ewhere f i [t ]denotes a primitiv e function suc h assubtraction ({[In t £In t !In t ])ortesting for zero (isz e r o [In t !Bo ol ]),orconstan tssuc h asin tegers (7[I n t ]).The combinators areclosed l am bda expressionsand thefollo winginformal de ﬂnitions clarify ourin ten tions:⁄[In t £In t !In t ]·‚h x 1;x 2i :x 1⁄x 22[(t 0!t2)!(t 1!t 0)!(t 1!t 2)]·‚f:‚g:‚x:f (g x )Tupl e [(t 0!t 1)!(t 0!t 2)!(t 0!t1£t 2)]·‚f:‚g:‚x:h f x;g x i Appl y [((t 1!t 2)£t 1)!t 2]·‚hf;x i :(f x )C ur r y [((t 0£t 1)!t 2)!(t 0!(t 1!t 2))]·‚f:‚x:‚y:f h x;y i The use ofcombinators will p ro ve useful when de ﬂning an in terpretation for expressions.Example The Miranda TM -lik e factorial functionfac n =1;if n =0=n ⁄fac(n-1),otherwisewith theargumen t n supplied atrun-time is writtenfac =ﬂx (‚f.Cond (Iszer o,1,2(⁄,Tuple (Id,2(f,2({,Tuple (Id,1)))))))where we disp e nse with t ypesfor readabilit y .¥33P arameterized Seman ticsAs we wan t toin terpret thelanguage i ndiﬁeren t wa ys,it is con venien t toofthebasic i ngredients. p ar ameterize theseman tics u pon an in terpretationof t,wheret ype then[[t]](I)will b e thein terpretationIf t is a compile-timetherun-time t ypes.W e ha veI is a function whic h in terprets[[A i]](I)=A i[[t1£t2]](I)=[[t1]](I)£[[t2]](I)[[t1!t2]](I)=[[t1]](I)![[t2]](I)[[t1!t2]](I)=I(t1!t2)pro duct where A i will b ethe atdomain of abase t ype,£forms the cartesianand!forms thecon tin u ousfunction space.is deﬂnedin m uc h the samewa y.To handle The in terpretationof expressionse clauses arewe needan en vironmen t env,sosomeillustrativv ariables[[x i[t]]](I)=‚env:env(x i[t])[[‚x i[t]:e]](I)=‚env:‚v:([[e]](I)env[v x i[t]])[[f i[t]]](I)=‚env I(f i[t])[e1]](I)env)([[e2]](I)env)[[2[t](e1;e2)]](I)=‚env:I(2[t])([It should be clear h o w toextend this deﬂnition tothewhole language. 3.1The StandardSeman tics Sm ustcapture t hein tuitive notion ab outthet ypesand Thisin terpretationinourlanguage.W e deﬂneexpressionsS(A i)=A iS(t1£t2)=(S(t1)£S(t2))S(t1!t2)=(S(t1)!S(t2))anduse liftingbet weene.g.t he undeﬂnedpair andthe pair of todistinguishundeﬂnedelemen t s.4To relate elemen t sfroma domain D with bottomelemen t ?D and domain D ?with bottomelemen t ?we de ﬂne up :D !D ?and dn :D ?!D by8d 2D :up (d )=d 8d 2D ?:up (d )=‰?D if d =?d;otherwiseThe in terpretation ofexpressions is mostly rather s traigh tforw ard.Some ex-amples areS (⁄[t ])=up (‚x:x 1⁄x 2where(x 1;x 2)=dn (x ))S (2[t ])=‚g 1:‚g 2:‰up (‚x:dn (g 1)(dn (g 2)(x )));if g 16=?^g 26=??;otherwise S (C ond [t ])=‚g 1:‚g 2:‚g 3:8>>>><>>>>:up (‚x:8<:dn (g 2)(x );if dn (g 1)(x )=tr ue dn (g 3)(x );if dn (g 1)(x )=fal se ?;if dn (g 1)(x )=?9=;);if g 16=?^g 26=?^g 36=??;otherwiseForthe ﬂx [(t !t )!t ]op erator we m ust restrict ourself tothecases w here t do esnotcon tain an y underlined t ype constructor (t is pur e ),where t hastheform t 1£t 2butis notpure,and ﬂnally w here t hastheform t 1!t2(t is a fr o ntier t ype).The missing c ase is when t =t 1!t 2butnotpure.In this c ase there d o esnotexist a general de ﬂnition,butby making restrictions (e.g.on thewell-formedness rules)we cana void this t ype [15].W e de ﬂneS (ﬂx [(t !t )!t ])=‚G:Fn ‚0G n (?),if t is pureS (ﬂx [(t !t )!t ])=‚G:(G 1;G 2(G 1)),if t =t 1£t 1andnotpurewhere G 1=S (ﬂx [(t 1!t 1)!t 1])(‚x 1:w 1where(w 1;w 2)=G (x 1;G 2(x 1)))G 2=‚x 1:S (ﬂx [(t 2!t 2)!t 2])(‚x 2:w 2where(w 1;w 2)=G (x 1;x 2))The latter de ﬂnition arises froma version ofBeki •c ’s Theorem[2,18].To motiv a tethemissing d e ﬂnition f or fron tier t ypes t =t 1!t2,consider theexpression ‚G:t n ‚0G n (?)whic h isthenatural d e ﬂnition t o usefor5S (ﬂx [(t !t )!t ]).Howev er,when G belongs t o[[(t 1!t 2)!(t 1!t 2)]](S )itislik elythat G (?)=?as we ha ve made thein terpretation strict in?2[[t 1!t 2]](S ),so that t n ‚0G n (?)=G (?)=?whic h isundesirable.Instead,let ususetheelemen t up (?)just ab o ve thebottomelemen t ?and de ﬂneS (ﬂx [(t !t )!t ])=‚G:t n ‚1G n (up (?));if t =t 1!t2whic h is well-deﬂnedas G (up (?))=?implies G (?)=?and S (ﬂx [(t !t )!t ])=?,and G (up (?))A ?implies that (G (up (?)))n ‚1isa c hain.Example The in terpretation of fac by S is Example The in terpretation of fac by S is[[fac ]](S )=‚env :G n ‚1(‚f :up (‚x:‰1;if x =0x ⁄dn (f (x ¡1);if x 6=0 ))n (‚x:?)if S (Isz er o [t ])=up (‚x:x =0)and S (1[t ])=up (‚x:1).¥3.2The Strictness Analysis AThe strictness analysis will b eform ulated a sanabstract in terpretation [1,6].All ground t ypeswill b e in terpreted by thedomain(f 0;1g ;v )with 0v 1,sowe ha veA (A i )=f 0;1g A (t 1£t2)=(A (t 1)£A (t 2))?A (t 1!t 2)=(A (t 1)!A (t 2))?Thein terpretation of expressions is rather standard [1,6,11,16](with resp e ct toour domains),andfor a fewillustrativ ecombinators andop erators weha veA (⁄[t ])=up (‚a:a 1u a 2where(a 1;a 2)=dn (a ))A (2[t ])=‚s 1:‚s 2:8<:up (‚a:dn (s 1)(dn (s 2)(a )));if s 16=?^s 26=??;otherwise6A (C ond [t ])=‚s 1:‚s 2:‚s 3:8>><>>:up (‚a:‰dn (s 2)(a )t dn (s 3)(a );if dn (s 1)(a )=1?if dn (s 1)(a )=0 );if s 16=?^s 26=?^s 36=??;otherwiseA (fix [(t !t )!t ])=‚F:F n ‚1F n (up (?));if t =t 1!t2Example If A (Isxer o [t ])=up (‚a:a )and A (1[t ])=up (‚a:1)we get[[fac ]](A )=‚env :up (‚a:a )sothat fac indeed is a strict function.¥3.3The Co de Generation CThe co de to be generated will be for a stac k based machine.The stac k con tains b ase values s uc h asbooleans a ndin tegers,p airs of the form h v 1;v 2i ,thunks f C;v g topostp o nethe actual ev aluation of C with v onthe top of the stac k,and closur es f C ;v g torepresen tfunctions asdata objects.W e de ﬂne Val tobe theset ofall stac k v alues.The instructions tomanipulate thestac k areins ::=const b j sub j mult j iszero j enter j switch jbranch (C ;C )j tuple j fst j snd j curry (C )j apply jdelay (C )j resume j callrec (l ;C )j call l j recb ::=true j false j 0j 1j 2j¢¢¢The instruction se quenc e C isa mem berof Code ,theset ofall possible mstructlon sequences:C ode =f i 1:i 2:::::i k j k ‚1;i j isan instruction for 1•j •k g [f †g 7The symbol†2C ode denotes t heempt y instructionsequence.seman tics i sdeﬂnedby therelation7!on conﬂgurations. The op erationalareSome example transitions(const b:C;v:ST)7!(C;b:ST)(sub:C;h v1;v2i:ST)7!(C;v1¡v2:ST)(enter:C;v:st)7!(C;v:v:ST)(switch:C;v1:v2:ST)7!(C;v2:v1:ST)(b ranch(C1;C2):C;true:ST)7!(C1:C;ST)(b ranch(C1;C2):C;false:ST)7!(C2:C;ST)(tuple:C;v1:v2:ST)7!(C;h v1:v2i:ST)(delay(C0):C;v:ST)7!(C;f C0;v g:ST)(resume:C;f C0;v g:ST))7!(C0:resume:C;v:ST)(resume:C;v:ST)7!(C;ST),if v is nota th unk(callrec(l;C0):C;ST)7!(C0[callrec(l;C0)=l]:C;ST)\call l"with sequence C[C0=l]is C where ev ery instructionThe instructionsequence C0.a free l ab el\l"is substitutedwith theinstructionExample IfC=enter:call1:resume:tuple:multC0=resume:iszerothen C[C0=l]=enter:resume:iszero:resume:tuple:mult but C[C0=2]=C asthelab el2do esnotoccur in C.callrec(1;C)[C0=1]=callrec(1;C)asthelab elinthein-Furthermore,\call1"in C becomes bound,and callrec(2;C)[C0=1]=structionfree.¥callrec(2;C[C0=1])asthelab el1in C is stillWith exe cution s e quenc e s we mean sequences oftheform¢=(C0;ST0)7!(C1;ST1)7!¢¢¢7!(C i;ST i)7!¢¢¢whic h may beﬂnite o rinﬂnite.W e will w rite¢(i)for(C i;ST i)and¢(i:::)(C i;ST i)7!(C i+1;ST i+1)7!¢¢¢.Furthermore,for thesub-sequencelet usfor ev ery l2f⁄;!;1g[I N deﬂne8E xSeq(⁄)=f¢j¢isﬂnite gE xSeq(!)=f¢j¢is inﬂnite gE xSeq(1)=f¢j¢isﬂnite orinﬂnite gE xSeq(m)=f¢2E xSeq(⁄)j thelength o f¢;#¢,is m gE xSeq(l;C)=f¢2E xSeq(l)j9ST:¢(0)=(C;ST)gE xSeq(l;C;v)=f¢2E xSeq(l)j¢(0)=(C;[v])gsequence C=enter:const3:switch:tuple:sub Example Theinstructiontheexecution sequenceandthestac k ST=[7]initiates¢=(enter:const3:switch:tuple:sub;[7])7!(const3:switch:tuple:sub;[7;7])7!(switch:tuple:sub;[3;7])7!(tuple:sub;[7;3])7!(sub;[(7;3)])7!(†;[4])sothat¢2E xSeq(5) E xSeq(⁄)and¢(5)=(†;[4]).of t ype Since w ewan ttogenerate co defor run-time functions,i.e.expressionst1!t2,it is natural toexp ect C(t1!t2)=C ode?.(Thebottom elemen t?iswe tomake Code a domain.)H owev er,when coming torecursion necessaryfor the lab els,solet usinstead generate r elo c atable c o de, need fresh v ariablesthat is co defromthe domain RelCode=I N!C ode?with the ordering vdeﬂnedbyR C l v R C2()8d2I N:R C1(d)=?_R C1(d)=R C2(d)then isThe t ype part oftheco degenerationC(t1!t2)=[[t1!t2]](A)£RelCodesothat theresultsA are a v ailable.analysisfromthestrictnessco dewe will o bserv e t wo conditions:IngeneratingA:The co de makesno assumptions ab outwhether theinitialv alue on top ofthestac k is a th unk ornot.9B:Iftheexecution oftheco de terminates thenthetopofthestac k willnev erbe a th unk,andexcept f or the topv alue,t he stac ksinthe initial andﬂnal con ﬂgurations will b e thesame.When expressing correctness of the co degeneration with resp e ct tothe stan-dardseman tics w e will s ho w that these conditions are observ ed.Consider theclause for ⁄[t ]:C (⁄[t ])=(A (⁄[t ]);‚d:resume:enter:snd:resume:switch:fst:resume:tuple:mult)The ﬂrst resume instruction is duetocondition A ,andthe mult instruction ensure that we do notlea v e a th unk on thestac k (condition B ),sothat it isnotnecessary toterminate theinstruction sequence w ithan additional resume instruction.Thisis similar toa co de generation withno strictness analysis [18].When lo oking at 2[(t 0!t 2)!(t 1!t 0)!(t 1!t 2)]we canusethe strictness information togenerate sligh tly better c o de:C (2[t ])=‚(s 1;R C 1):‚(s 2;R C 2):(s;R C )where s =A (2[t ])(s 1)(s 2)R C =‚d:8>><>>:‰R C 2(d ):R C 1(d );if dn (s 1(?)=?delay (R C 2(d )):R C 1(d );otherwise ;if R C 1(d )6=?^R C 2(d )6=??;otherwiseIf the ﬂrst argumen t expression to 2[t ]is strict (i.e.dn (s 1)(?)=?),we can disp e nse with the delay instruction,unlik e inthesimple c o degeneration.Concerning t he ﬂx [(t !t )!t ]op erator i nthecase of t =t 1!t 2,we calculate thestrictness information by ignoring theco de,sothatC (ﬂx [(t !t )!t ])=‚F:(s;R C );if t =t 1!t2where s =t n ‚1(‚s 0:(w 1where (w 1;w 2)=F (s 0;¢)))n (up (?))10R C =‚d:‰callrec (d;C d );if C d 6=??;otherwiseC d =(w 2where (w 1;w 2)=F (s;‚d 0:call d ))(d +1)The dot\¢"in F (s 0;¢)is a shorthand for the relo catable instruction sequence ‚d:?.W e will l ater see that sis indep e nden t ofthe actual c hoice o finstruc-tion sequence,sothat an y instruction sequence would be feasible.Example Ifwe de ﬂne C (Isz er o [t ])=(up (‚a:a );‚d:resume :iszero )and C (1[t ])=(up (‚a:1);‚d:const 1)we get[[fac ]](C )=‚env :(up (‚a:a );‚d:callrec (d;C ))whereC =enter:resume:iszero:branch (const 1,enter:delay(e nter:delay(const 1):switch:delay(resume):tuple:C :calld):switch:delay(resume):tuple:C ⁄)C =resume:enter:snd:resume:switch:fst:resume:tuple:sub C ⁄=resume:enter:snd:resume:switch:fst:resume:tuple:mult Our analysis detects thestrictness ofsubtraction,m ultiplication and the recursiv e call,and we areth us able toa voidthegeneration ofa delay in-struction around theco defor theﬂrst argumen t toall 2[t ]-com binators.¥4Correctness usingPredicatesInorder toexpress t hecorrectness ofthestrictness analysis and theco de generation,we will adopttheframew orkof lo g ic a lr elations [20,21]and Kripke-lo gic a lr elations [21,22].Deﬂnition1(F rom [17])An indexed relation overtheinterpr etations I 1;:::;I m is a c ol le c tion o fr elations11R t:[[t]](I)£:::£[[t]](I m)!f tr ue;fal se g onefor e achtyp e t.It is a logicalrelationif andonly ifR t1!t2(f1;:::;f m)·8(x1;:::;x m):R t1(x1;:::;x m))R t2(f1(x1);:::;f m(x m))holds for al ltyp e s t1and t2.A Kripk e-indexed relationover a non-empty p artiallyor der e d set›andthe interpretations I1;:::;I m is a c ol le c tion o fr elationsR[§]t:[[t]](I1)£:::£[[t]](I m)!f tr ue;fal se gonefor e achtyp e t,wher e8§0w§:R[§]t(x1;:::;x m))R[§0]t(x1;:::;x m)holds foral l typ e s t.Itisa Kripk e-logicalrelationif and only if itisa Kripke-indexed r elation andR[§]t1!t2(f1;:::;f m)·8§0w§:8(x1;:::;x m):R[§0]t1(x1;:::;x m))R[§0]t2(f1(x1);:::;f m(x m))holds for al ltyp e s t1and t2.When coming totheﬂx[t]-op erator it is necessarytoensure t he admissibility ofourpredicates.Deﬂnition2A pr e dic a te R on the domain D is admissibleif1.R(?)holds.2.If(d n)n is a chain on D and R(d n)holds,then R(t n(d n)n)holds.To sho w that the relationshold we will u se the principleofstructuralinduc-tion.Deﬂnition3(F rom[17])An indexe d r elation R over I1;:::;I m admit structuralinductionwhenever i t satisﬂes,that if12R t0([[`]](I1);:::;[[`]]I m))holds for al lb asic op er ators and c ombinators`oftyp e t’o c curring i nan expr e ssion e oftyp e t,thenR t([[e]](I1);:::;[[e]]I m))holds.A Kripke-indexed r elation R over›and I1;:::;I m admit structuralinduc-ﬂes,that iftion whenever i t satisR[§]t0([[`]](I1);:::;[[`]]I m))holds for al l§2›andfor al lb asic op er ators andc ombinators`oftyp e t’o c cuning inan expr e ssion e oftyp e t,thenR[§]t([[e]](I1);:::;[[e]]I m))holds.W e no w ha vegic a l r elationsadmitaswel lasKripke-loFact4(F rom[17])Lo gic a l r elationsalinduction.structurwing.This fact will b e utilizedinthefollo5Correctness ofthe Strictness Analysisin C is correct with resp e ctcollectedinformationTo verify that the strictnessval A t for t run-time and tothe standard seman tics,wedeﬂnet wo predicates:tforw ard:The deﬂnitions are quite s traighcompA t for tcompile-time.val A t:[[t]](A)£[[t]](S)!f tr ue;fal se g(a;x)·x6=?)a=1val A Ai13val A t1£t2(a;x)·x6=?)(a6=?)^val A t1(a1;x1)^val A t2(a2;x2) 1;a2)=dn(a);(x1;x2)=dn(x)val A t1!t2(s;g)·g6=?)(s6=?)^(8a;x:val A t1(a;x))val A t2(dn(s)(a);dn(g)(x)))W e seethat8a:val A t(a;?)and8x:val A t(>;x)bothhold,i.e.ev ery abstract v alue describestheseman tic v alue?and ev eryseman tic v alue is describedby thetopelemen t oftheappropriateabstract domain.compA t:[[t]](C)£[[t]](S)!f tr ue;fal se gcompA Ai(x;y)·x=ycompA t1£t2((x1;x2);(y1;y2))·compA t1(x1;y1)^compA t2(x2;y2)compA t1!t2(F;G)·8x;y:compA t1(x;y))compA t2(F(x);G(y))compA t1!t2((s;R C);g)·val A t1!t2(s;g)Lemma5The clauses for c ompA deﬂne an admissiblepr e dic a te.Proof A simple s tructuralinductionon thet ype t.¥The correctnessofthestrictnessanalysis no w amoun tsto sho wing that compA holds for all basic o p erators andcombinators.Proposition6The pr e dic a te compA t([[e]](C);[[e]](S))holds f or every expr e s-sion e oftyp e t.Proof As c ompA is a logicalrelationwe only needtoconsider eac h combi-nator and op erator(F act4).It is quite s traightforw ard,see e.g.[13],solet usonly consider theop eratorﬂx[(t!t)!t]inthecase t=t1!t2. Assume compA t!t(F;G),deﬂnes n=(‚s0:(w1where(w1;w2)=F(s0;¢)))n(up(?))g n=G n(up(?))andlet usby inductionon n sho w that148R C:compA t((s n;R C);g n)(P n)y of compA.The base case n=0is immediate b y admissibilitUsing(P n)and compA t!t(F;G)we get compA t(F(s n;¢);G(g n)),butg n+1=G n+1(up(?))=G(g n)ands n+1=(‚s0:(w1where(w1;w2)=F(s0;¢)))(s n)=w1where(w1;w2)=F(s n;¢)whic h completes thepro of,since c ompA t((s n;R C);g n)·val A t(s n;g n)and y of compA.¥by admissibilitisinformation oftheab o ve pro of,we see that thestrictnessAs a corollaryofﬂx[t]by C,infact, indep e nden t oftheco de,sothat thein terpretationmake sense.is[1,4],where a suit-analysisof a strictnessOther approac hes tocorrectnessho wev er,is just a nother function is deﬂned.The predicates,able abstractionfunctionﬁt:if whenev er val A t(a;x)also wa y ofdeﬂning suc h an abstractionprop erties ofan abstrac-ﬁt(x)v a,thenﬁt would resp e ct the c haracteristiction function.6Correctness ofthe Co de Generationed by awill consist ofthree la yers,eac h describThe pro ofofcorrectness,thesecond predicate.Theﬂrst la yerensures t hatﬂx[t]isusedcorrectlyensures that the generated co debeha veswell o n the stac k, la yeradditionallyanalysis and,ﬂnally,thelast la yerensures thecorrectnessofthestrictness andthegenerated co de.need toincorp orate t he This approac h is similar to[18],butwe additionallypredicate.This will,aswe shall s ee, analysisin tothecorrectnessstrictnesscause no di–culties.156.1The Substitution Propert yThisprop ert y isneeded toguaran t eethat theco de forﬂx[t]will only be applied t ofunctionsthat may be regarded a srelo catable co de withholes. First,deﬂnecompS0[§]t:[[t]](C)£[[t]](C)!f tr ue;fal se gcompS0[§]Ai(x;y)·x=ycompS0[§]tt£t2((x1;x2);(y1;y2))·compS0[§]t1(x1;y1)^compS0[§]t2(x2;y2)compS0[§]tt!t2(F;G)·8§0¶§:8x;y:compS0[§0]t1(x;y))compS0[§0]t2(F(x);G(y))compS0[§]t1!t2((s1;R C1);(s2;R C2))·8d>max(dom( )):compS00[§]t1!t2(R C1(d);R C2(d))where comps00[§]t1!t2(C1;C2)·(C2=?)C1=?)^(C26=?)(C16=?)^C1[§]=C2^F r eeLab(C1) dom(§)) The function Fr e eL ab:Code!f D j D I N g collectsthefree lab els inan instructionsequence.The parameter§,denoting a substitution,is a set of pairs o flab els andco de.With dom(§)we mean the set f l j(l;C)2§g,and whenev er(l;C1)2§and(l;C2)2§then C1=C2.Lemma7The clauses for c ompS’[§]deﬂne an admissiblepr e dic a te. Proof A simple s tructuralinductionon thet ype t.¥The desired prop ert y can no w be stated a s the Substitution P ropert y [15,18]:Proposition8Assume that compS0[§]t!t(F0;F)holds for every typ e t= t1!t2andthat for d>max(dom(§))andevery s2[[t]](A)we have deﬂne d C=(w2where(w1;w2)=F(s;‚d0:call d))(d+1)C0=callrec(d;C)C00=(w2where(w1;w2)=F(s;‚d0:C0))(d+1)ThenC6=?)C[C0=d]=C00^F r eeLab(C0) dom(§)16holds.\call l"may The prop osition sa ysthat the\hole"in C(the instructionC00.safely be substitutedwith C0yieldingProof Assume C6=?,deﬂne C0using F0inthesamewa y as C is deﬂned using F,andconsider thet wo stages1and2.Stage1:Extend§to§1=§[f(d;call d)g.FromcompS0[§2]t((s;‚d0:call d);(s;‚d0:call d))we get compS0[§1]t((¢;‚d0:C0);(¢;‚d0:C))sothat F r eeLab(C) dom(§)[ f d g and C=C0[§].Stage2:to§2=§[f(d;C0)g.FromcompS0[§2]t((s;‚d0:cal ld);(s;‚d0:C0))we get compS0[§2]t((¢;‚d0:C0);(¢;‚d0:C00))so that C00=(C0[§])[C0=d]= C[C0=d]whic h completes thepro of.¥tobe able to W e only needtosho w that compS0holds for ev eryexpressionuseProp osition8:Proposition9The pr e dic a te compS0[§]t([[e]](C);[[e]](C))holds for every§andevery expr e ssion e oftyp e t.it is su–cien trelationProof As the predicatecompS0[§]is a Kripk e-logicaltosho w that compS0[;]t([[e]](C);[[e]](C))holds.F orev eryop erator a nd com-tforw ard,for theﬂx[t]op erator w e binator o ther thanﬂx[t]this isstraighmimicStage1ofProp osition8.¥;and iden t ical argu-As we only use compS0withan empt y substitutioncompS t:[[t]](C)!f tr ue;fal se g byrelationments,let usdeﬂne thelogicalcompS t(x)·compS0[;]t(x;x)andusethis deﬂnition inthefollowing.176.2The W ell-b eha vednessPredicateTo ensure that theco de only transformsthetopelemen t ofthestac k in to another w ell-beha vedelemen t,weuse the val W and compW predicates.The val W predicateensures thewell-beha vedness o fa stac k elemen t:val W t:V al!f tr ue;fal se gval W Ai (b)·tr ue for all basic v alues b oft ype Aival W t1£t2(h v1;v2i)·val W t1(v1)^val W t2(v2)val W t1!t2(h C;v0i)·8v1:val W t1(v1))val W t2(f C;h v0;v1i g)val W t(f C;v g)·8¢2E xSeq(⁄;C;v):postW t(¢)^nothunk(¢) The predicatepostW tells uswhether a co de sequence¢ends with a well-beha vedelemen t on the stac k,and nothunk ensures that the last e lemen t on thestac k is nota th unk.postW t;nothunk:E xSeq(m)!f tr ue;fal se gpostW t(¢)·9v:¢(m)=(†;[v])^val W t(v)nothunk(¢)·:9C;C0;v;ST:¢(m)=(C;f C0;v g:ST)The deﬂnition of val W t(f C;v g)sa ys,that if we execute C with v on topof thestac k,we endup with a well-beha vedelemen t on thestac k whic h is not a th unk.The well-beha vedness p redicatecompW t:[[t]](C)!f tr ue;fal se g is deﬂned asfollows:compW Ai(x)·tr uecompW t1£t2((x1;x2))·compW t1(x1)^compW t2(x2)compW t1!t2(F)·compS t1!t2(F)^(8x:compW t1(x))compW t2(F(X)))compW t1!t2((s;R C))·compSW t1!t2((s;R C))^(8d>0:compSW t1!t2(R C(d)))where compSW t1!t2(C)·C6=?)(8v2V al:val W t1(v))val W t2(f C;v g))18Lemma 10The clauses for c ompW deﬂne an admissible pr e dic a te.Proof First w e m ust de ﬂnea well-founded order …on t ypesandv alues b y(t 1;v 1)…(t 2;v 2)()(t 1is a prop ersubt y pe of t 2)_(t 1=t 2^v 1isnota th unk ^v 2is a th unk)Consider t heneac h clause f or val W t (v ).If v isnota th unk,theneac hval W t 0(v 0)on therigh t hand side has(t 0;v 0)…(t;v )since t 0isa subt y pe of t .If v is a th unk,thenwe ha ve val W t 0(v 0)on therigh t hand side with t =t 0,but v 0is nota th unk by nothunk ,so(t 0;v 0)…(t;v ).As the predicate val W no w is well-de ﬂned,the admissibilit y of compW is aneasy structuralinduction on thet ypes.¥W e are no w ready tosho w that compW holds for all op erators and combi-nators.Proposition 11The pr e dic a te compW t ([[e ]](C );[[e ]](S ))holds for every ex-pr ession e oftyp e t.Proof Even though compW is nota logical relation,it is an instance ofa Kripk e -la yered predicate whic h admits structural induction [17].Therefore,for eac h op erator orcombinator,consider an execution sequence¢2E xSeq (m;C 1:C 2:::::C k )anddecomp oseit in toexecutionsequences ¢i (m i ;C i )for i 2f 1;:::;k g .Then either use the induction hypothesis on ¢i orwrite ¢i outindetail toget the desired result.A full p ro ofofwell-b eha vedness c anbe found in[18],yetfor a simpler co degeneration.¥6.3The Correctness PredicateForrun-time objects we de ﬂne val C t :V al £[[t ]](S )!f tr ue;fal se g asfol-lo ws:val C A i (b ;x )·val W A i (b )^B i [[b ]]=x val C t 1£t 2(h v 1;v 2i ;x )·9x 1;x 2:x =up (x 1;x 2)^19val C t 1(v 1;x 1)^val C t 2(v 2;x 2)val C t 1!t 2(f C ;v 0g ;g )·val W t 1!t 2(f C ;v 0g )^(g 6=?)^(8v 1;x :val C t 1(v 1;x ))val C t 2(f C;h v 0;v 1i g ;dn (g )(x )))val C t (f C;v g ;x )·val W t (f C;v g )^val W C t (f C;v g ;x )where val W C t ·8¢2E xSeq (1;C;v ):(¢2E xSeq (!))x =?)^(¢2E xSeq (⁄))postC t (¢;x )^nothunk (¢))The function B i :V al ![[A i ]](S )maps a basic v alue to its appropriate coun terpart inthestandard s eman tics.F oran example,B bool (true )=true and B int (7)=7.The predicate postC is de ﬂnedm uc h as postW ,theonly di ﬁerence b eing an additional parameter t otheseman tic v alue and using val C instead of val W .W e omitthedetails.Finally ,we de ﬂne compC t :[[t ]](C )£[[t ]](S )!f tr ue;fal se g by thefollo wing clauses:compC A i (x;y )·x =ycompC t 1£t 2((x 1;x 2);(y 1;y 2))·compC t 1(x 1;y 1)^C ompC t 2(x 2;y 2)compC t 1!t 2(F;G )·compW t 1!t 2(F )^compA t 1!t 2(F;G )^compW C t 1!t 2(F;G )where comp W C t 1!t 2(F;G )·8x;y :compC t 1(x;y ))compC t 2(F (x );G (y ))compC t 1!t 2((s;R C );g )·compW t 1!t 2((s;R C ))^compA t 1!t 2((s;R C );g )^(8d >0:compW C t 1!t 2(R C (d );g ))where comp W C t 1!t 2(C;g )·(C =?)g =?)^(C 6=?)g 6=?^(8v;x :val C t 1(v;x ))val C t 2(C;v;dn (g )(x ))))Before c on tin u ing with the pro of of correctness,wem ust besure the predicate is well-de ﬂned.Lemma 12The clauses for c ompC deﬂne an admissible pr e dic a te.Proof Similar tothepro ofofLemma 10,this is a structural induction on thet ype t .¥20。

1带翻译

1、1、金融用语：受取手形：应收票据；外貨ポジジョン：外汇头寸；公定歩合：法定贴现率；最割引率：再贴现率；つなぎ融資：过渡性融资；変動為替レート：浮动汇率2、股市用语：上げ幅：升幅；先安：看跌；そこを割る：跌破最低大关；持ち合い：暂告平息；軟調：疲软3、缩略语：ADBゕジゕ開発銀行（亚洲开发银行）；CIEC 国際経済協力会議（国际经济合作会议）；GA TT関税貿易一般協定（国际关税和贸易总协定）；FAO 国連食料農業機構（联合国粮农组织）；IMF 国際通貨基金（国际货币基金组织）；JICA国際協力事業団（日本国际事业协力团）OPEC石油輸出国機構（石油输出国组织）；UNDP国連開発計画（联合国开发计划署）一、经济类文章○円の国際化変動相場制の第二の不均衡は、日本の貿易収支の大幅な黒字である。

確かに第二次石油ショックの直後こそ貿易収支は赤字またはわずかな黒字だったが、数年後には大幅黒字が復活している。

79年の第二次石油ショックの後も、79－80年こそ、貿易収支は２０億ドル前後の赤字、経常収支は大幅の赤字だったが、81年以降再び黒字を増やし、83年には経常収支も黒字となった。

85年、86年は貿易収支各461億ドル、828億ドル、経常収支は各350億ドル、492億ドルの黒字である。

普通ならとっくに円高となってよさそうだが、そうならなかったのは、日本からゕメリカへ莫大な金利稼ぎの長期資本が流出したからである。

この時期の貿易黒字の急増は、日本の輸出努力とともに、ゕメリカのドル高のあおりを受けたと見るのが正しいだろう。

かつては通貨レートは貿易の動きに依存していたが、現在では、資本収支の動きが大きな影響を持つようになっている。

それだけに、貿易摩擦問題が通貨レート調整によって解決する見通しは少ない。

むしろ日本側は、経常収支の黒字を対外投資の推進に振り向け、円高を避けてきた。

实行浮动汇率制度的第二个不均衡问题是日本的贸易收支顺差大幅度。

Technical Innovation

Time (second)
Received November 24,1997; acceptedafterrevisionJanuary27,1998. Presented atthe annualmeetingoftheAmericanRoentgen RaySociety,Boston,May1997.
StudyDesign After approval of the study by the investiga volunteer. Representativecine phase-contrast graph of infrapopliteal artery flow shows peak forward flow beginning 0.25 sec after ECGR-wave and con
time-of-flight (TOF) sequences (nongated) using
were first describedby Likes [3]. The first spi
ral images were produced in 1986 [4]. Previ ous studies that applied this technique to imaging the coronary [2J and carotid arteries
Technical Innovation
Spiral MR Angiography of the Popliteal Trifurcation
Liam0. Spence1,RichardTeIIo1, E.KentYucei1,Marc Kouwenhoven2, Jan Groen2
M R angiography has been proven to

(完整word版)专业学位硕士研究生英语教程14

unit 14SciencePreviewOur humans have been always confused by some questions since we are thrown into the world by God. Those are ”what is our place in the universe?" and "where did it and we come from?” To try to answer these questions，people have created dif ferent ”world pictures". Some are scientific，some are mythic，some are hypothetical and some are just imaginary. There is another effort to stir the readers' imaginations about the same questions. The exploration will never stop its steps until our human can get the truth one day.Text ReadingWarm—up,.。

1）Match the words in Column A for the proper day in Column B。

A world-known Christian story, Genesis, has explained who created the world and why it should be. In this famous story, God spent 7 days in creating the world. Now your task is to match the proper day for each item。

郑景婷考研英语高频词汇(打印版)

考研英语高频词汇1.a host of = a lot of 大量2.abandon = give up 放弃3.absence 没有，不存在4.abide by = obey; comply with, conform to 遵守5.ab normal ities 不正常6.absolute of: relative; comparative 绝对的7.absor ption 吸收，理解8.abstract of: concrete 抽象的；摘要9.abundance—abundant ly=rich (ness) 充足；大量10.ab use滥用11.accelerate—acceleration =speed up 加速12.access to—access ible 接近；获得13.accommodate—accommodation 提供食宿；以适应14.accomplish ment =achievement 成就，圆满完成15.account for 解释；占据百分比16.ac count ant 会计17.accumulat ion 积累18.accura cy—accura te 精确性19.ac know ledge 公认、承认20.acquaint ance 熟人；熟悉（with）21.acquir e—acqui sition—acqui sitive 获得；学会；习得；合并22.act on 对…起作用23.act ively 积极地；主动地24.adapt to 适应25.addict 上瘾26.address 称呼；强调27.adjoin 毗邻28.adjust 调节29.admir ation 景仰；崇拜30.admi ssion 录取；允许进入；门票31.adopt 领养；采纳32.adventur ous 冒险的；历险的33.advis ability—advis able—advis or—advi s ory 可取性—值得建议的—建议者—指导性的34.advocate 支持；拥护（者）35.affiliate 附属36.affinity 关系；酷爱37.afford 买得起；承受得起代价38.agenda 议事日程39.agent 代理人；主体40.aggravate=worsen 恶化41.aggressive 挑衅的，好斗的；积极进取的42.aging 衰老的43.agony （身心的）极大痛苦44.aid=help45.aim 目标46.alien to 不相容的；与…相反的47.align with 与…一致48.all but=almost49.alleg ation 陈述；声称50.allocat ion 分配，拨给（款项）51.allow for 把…考虑在内52.alone 仅就…而言53.along one track 顺着某一做事方式54.alphabet—alphabet ically 字母表—按字母表顺序的55.alter 改变（衣服大小和容貌）56.alternative—alternative ly 选择；可供选择的—可供选择地57.amateur 业余的58.amazed—amaz ing 惊异的—令人惊异的59.ambiguous 容易引起歧义的；模棱两可的60.ambition 雄心；野心61.amid=in the middle of62.amount to=reach 达到；到达63.ample 大的；充足的64.analogous 类似物，近似物65.analys is—analyst 分析66.ancestor 祖先67.anchor 抛锚；停泊68.angle 角度69.announce 宣告70.anonymous 匿名的71.anticipate=expect72.anxi ety 焦虑73.anything but=not at all 一点也不74.apart from=besides 除…以外还有75.apparatus 设备；装置76.apparent—apparent ly 明显地77.appeal to=attract 吸引78.appli ance—appli cable—appli cation 用具；器具—申请；应用79.appreciate 欣赏；理解；感激80.apprehensive 忧虑的81.approach 途径；接近82.appropriate 合适的；恰当的83.arbiter 权威人士；仲裁员84.arbitrary 武断的；刚愎自用的85.arriv al 到达86.articulate 明确而有力地表达87.artist ic 艺术的88.aspired 有灵感的89.assault=attack 袭击90.assemble =get together 集合；组装91.assert 断言；声称92.assess—assess able 评估93.assign 安排；布置94.assimilate—assimilat ion 同化95.assist—assist ance =help 帮助96.assume—assum ption= take on 假设；承担；呈现97.assure 使某人确信98.astonish ing 令人震惊的99.at a loss =confused 迷惑的100.at random 随机地101.at the mercy of 任由某人处置102.at will 任意地；随意地103.attach importance to 强调；重视104.attain 达到；获得105.attempt 企图；试图106.attendance—attentive to 关注107.attitude 态度108.attribute to 把…归因于109.auditor 审计员；查帐人110.augment 扩大；增加；提高111.authentic 地道的112.authority—authori ze 权威—授权113.automate 自动化114.auxiliary 辅助的115.average 普通的；平均的116.a wake n 唤醒；唤起117.aware 意识到；知道118.awkwardly 尴尬地119.baby boom 婴儿潮120.back bone 栋梁；中坚121.bait 鱼饵，诱饵122.ban 禁止123.bank on 寄希望于124.barely 几乎不125.bargain 讨价还价；便宜货126.barrier 障碍127.baseline 底线128.be absorbed in 全神贯注于129.be bound up with 某事物关系密切130.be composed of 由…组成131.be confined to 局限于132.be engaged in 从事于133.be fascinated with 被…迷住了134.be indicat ive of 表明135.be obliged to 被迫做某事136.be opposed to 反对137.be rooted in 以…为根源138.bear able 可以忍受的139.belt 带状物140.benefi cial—benefit 有好处的—利益；对…有好处141.betray 背叛142.better off 经济状况变得更好143.beyond dispute毋庸质疑144.bias 偏见145.bilingual 双语的146.bill 法案147.bind ing 受法律约束的148.bio medical 生物医学的149.bitter 苦涩的，激烈的150.blind 盲目的151.block 阻碍152.bold 大胆的；冒进的153.bomb ard…with 攻击某人/物154.bonus 奖金；意外的好处155.boom 热潮156.booth 电话亭157.bore 使厌烦158.bound 注定；装订159.boundary 边界160.brake 刹车；阻碍因素161.brand 品牌162.break down 崩溃163.break through—breakthrough突破164.breakout 爆发165.breed 种；血统；滋生166.bright ening 照亮的167.bring out 产生168.bring under control 控制住169.broad ly 从广义上说170.brochure 小册子171.broker 经纪人172.bubble 冒泡；充满喜悦之情173.budget 预算174.build up 建立175.bulk 大块；大量176.bunch 一束；一簇177.burden some 造成负担的178.bureaucracy 官僚机构179.business 事务180.by a large margin 以较大差距赢利181.bypass 偏路182.byproduct 副产品183.call for 要求184.call on 拜访185.call up 打电话；召集186.campaign （没有硝烟的）战争187.candidate 候选人188.canteen 食堂189.cap ability—cap able 能力—能干的190.capacity 能力；容量191.capital—capital ism首要的/资本—资本主义192.captive—capture 俘虏—捕获193.care free 无忧无虑的194.carry out 实现；完成195.carry weight 有影响；有份量；有力196.casual—casual ly 随意地197.cater to 迎合，满足198.caution—cauti ous—cauti ously 小心；谨慎199.cease =stop 停止200.cement 水泥；巩固，加强201.census 人口普查202.central ization—central ize 中央集权化203.chain 连串；连锁店204.chair 主持205.channel 频道；渠道206.characteristics 特征207.cheery 喜气洋洋的208.chief ly 主要地209.child bearing 生孩子210.chip 薄片；芯片；电脑211.circ uits 电路；封闭线路212.circ umstance 条件213.citizen ry 公民身份214.civil—civil ization—civil ize 国内的—文明—使文明215.claim—claiming声称（对…具有所有权）216.clash 冲突217.class—class ify类别—分类218.classic 古典的；经典的219.clear-cut 明确的220.client 当事人；顾客221.climbing ladder 升职路径222.cling to 附着223.clinics 诊所224.clone 克隆；复制225.cluster 簇；丛/ 聚集226.code 方式227.co incidence 巧合228.collapse 坍塌229.col league 同事230.colony 殖民地bat 战斗；对抗e into being形成e on 进步；成长mand 掌握；精通mercial—commercial ized商业的；广告—商业化mi ssion—commit—commit ment 佣金；回扣—犯（罪，错误）modity 商品munity 一个群体mute 通勤（固定往返于两地之间）pany 陪伴par ative—compar ison 比较而言的—比较passion ate 有同情心的pel=force 强迫pensate—compensat ion=make up弥补；补偿petent ly能干地petition—competiti veness—co mpeti tor竞争—竞争激烈—竞争者pile编撰plement ary补充的ponent组成成分prehension 理解prehensive 全面的，综合的 press 压缩pulsion—compulsive 强制254.concept=idea 观念；概念255.concern担心，关心256.concise简洁的257.conclu sive结论性的258.concrete具体的259.con dense 浓缩260.conduct—conductive行为；进行，实施261.confer—confer ence商讨；授予—会议262.confess承认（坏事）263.confide泄露秘密264.con firm进一步证实265.conflict冲突266.conform—conform ity to 遵守；符合267.confront—confront ation面对；面临268.confus ion迷惑269.connotation 言外之意270.conscious有意识的271.consensus共识272.consent同意273.consequen ce—consequen t—conse quen tly结果—因此的—因此274.conserv ation—conserv ative保护；保守—保护的；保守的275.consider ably相当大地，相当多地276.consist—consist ently包含—前后一致地277.con solid ation巩固；加强278.conspicuous 明显的279.constitute—constitut ional组成—合乎宪法的280.construct = build建造281.consult ant—consult ation 咨询专家282.contemplative深思熟虑的；沉思的283.contemporary当代的；同时代的284.contempt—contempt ible轻视；蔑视—可鄙的285.contend—conten tion 主张；争辩286.context上下文；环境（抽象）287.continu ally—continu ous 断断续续的—连续不断的288.contract合同；收缩289.contradict—contradict ion—contrad ict ory 矛盾，对立，反驳290.contrari ly 相反291.contribute—contribut ing导致，造成292.controversial 有争议的293.convention—convention al常规—常规的294.convey= express表达295.convince—convinc ing使确信—有说服力的296.co operation—co-operative 合作—具有合作精神的297.coordinate—coordinat or 协调—协调员298.cope对付299.corporate—corporat ion 团体的，联合的—公司300.cor relation相互联系301.correspond—correspond ing一致；通信—有联系的302.cost ly昂贵的303.council市议会，市政厅304.counsel劝告，忠告/ 法律顾问305.counter balance—counter part平衡力，起平衡作用—相对应的人或物306.courage ous 无畏的，勇敢的307.course路线；课程308.cover the cost支付费用309.craft工艺310.creat ionism—creat ivity 创造主义—创造性311.credi bility可信度312.crisis危机313.criteria标准314.critical—critical ly—criticize—critics 评论—批评的，关键的—批评地，关键地—批评家315.crop收获，收割316.crucial关键的317.cruel ty残忍318.cultivate—cultivat ion培养319.cure治愈；疗法320.custom ary—custom ize习惯的，惯例的—顾客化（按顾客意见做）321.cut and dried 过分简洁的322.cut off 切断323.cute 可爱的324.cycle 周期325.data base 数据库326.dazzl ingly 令人目眩地327.deal with 处理；和…有关328.dece ptive 欺骗性的329.declar ation 宣告330.decline 下降；拒绝331.dedicate 有献身精神的332.deduce 演绎；推断333.deem=think 认为；相信334.deep en深化335.defeat打败336.defect ive有问题的337.defend—defend ant—defend er防御；辩护—被告—后卫338.defer ence 尊重，遵从，服从，顺从339.define—defin ition 下定义—定义340.definitely 确定无疑地341.de grad ation 降级342.delay =hold up耽误343.deliberately= on purpose 故意地344.delicate脆弱的，易损的345.deliver—deliver y送货；发言的方式技巧346.demand要求；需求347.democra cy—democra tic 民主—民主的348.demographer人口学家349.demonstrate—demonstrat ion=show 表明350.dense ly populated人口稠密的351.deny否认；否决352.depend ent upon依靠353.depict=describe 描写，描绘354.depletion削减；消耗355.depress ion抑郁症；经济萧条356.derive from=come from; result from 来自357.descend ant子孙后代358.desert沙漠；遗弃359.deserve理应得到360.desir able称心如意的361.despair—desperate绝望—不顾一切的362.detach of: attach 分离363.destin y 命运364.destr uction 毁灭365.detect ing 探测的366.determine—determin ism决定—决定论367.deteriorate 恶化368.detrimental =harmful 有害的369.de value d 贬值的370.devised 设计的371.devote 贡献372.die out 消亡373.differ—d iffer entiation不同—差异；区别对待374.diffuse 消散375.digi tal 数字的；数码的376.dignity 尊严377.dilute 稀释378.dimension 空间；维度379.di mini sh 逐渐变小；逐渐消失380.direct ory 电话簿381.dis able 残疾382.dis advantaged 处于劣势的383.discard 抛弃384.discern 辨别；识别385.discipline 纪律；学科386.dis comfort 不舒适387.dis connect 断开连接388.dis content with不满意；不满足389.discourse 话语390.dis cover y 发现391.discriminat ion歧视；鉴别；区别392.dis grace d 丢脸的393.disguise 伪装394.dis honest 不诚实395.dis honor 丢脸396.dis integrate 分解；瓦解；崩溃397.dis junction 不交汇398.dis order 无序；紊乱399.dis organize d无组织的400.disparaging贬低性言语401.dis passion无激情402.disperse 驱散403.dispute争执404.dis regard漠视，不关心405.dis satisfaction 不满意406.dis solve 溶解407.distant 遥远的408.dis taste for 无品味409.distinct ion—distinct ly 区别；明显地410.distinguish from区别411.distort歪曲；扭曲412.dis tract使分心413.dis trust 不信任414.diverse—diversity多元的，多样的—多元化，多样化415.diver sion 偏离，转向416.divi sive 造成分裂的417.do one’s bid 努力418.doctrine 教义419.dome 圆顶420.domestic 国内的；家庭的421.dominant—dominate占主导地位的—主导，支配422.doom 注定；劫数423.dos age—dose 剂量424.down scale 裁员425.down shifting 下降趋势426.down size 裁员427.doze off 打盹428.draft 草稿，初稿429.drama tic—drama tically—drama tize 戏剧性地—戏剧性的—戏剧化430.draw from 从中提取431.draw up 草拟；制订432.draw back 缺陷，不足433.dread—dread ful 可怕；可怕的434.drift 漂流435.driving force 驱动力436.drop out 中途退出437.dubious ly 怀疑地，犹豫地438.dull 笨拙的；沉闷的439.duplicat ion=copy 复制440.dur able 耐久的441.dwell 居住，详细讨论，总是考虑442.dynamic 动态的443.eager ness 热心，渴望444.effect 影响；导致—效果445.effort less 毫不费力的446.e labor ate 详尽的447.electronic—electronics电子的—电子学448.elegant 优雅的449.elevate 抬起，举起，升高450.eliminate—eliminat ion 消除451.elite—elit ism精英—精英主义452.ember 余烬453.embrace 拥抱，包含；体现454.emerge—emerge nce 出现455.emergency 紧急情况456.eminent =outstanding; remarkable; famous457.emit 发出，散发458.emphasi s 重点459.en counter 遇见460.en danger 使有危险461.endeavor 努力462.end less 无尽的463.ends 目的464.endure 忍受465.energ etic 精力充沛的466.enhance加强，增强467.en light en 启发468.en list注册；招募469.enquir y 询问；调查470.en rich 使丰富471.en sure 确保472.entail 使…成为必要473.enterprise 事业；企业474.entertain er 娱乐者475.en throne 使就任；提拔476.enthusiastic 热心的，热情的477.entire ly 完全地478.entitle 使有权做某事479.entrepreneur 企业家480.envy 嫉妒481.epidemic 流行性的482.episode 片断483.epithet 描述性短语484.equa te…with 等同于485.equi valent 相等的486.essen tial 必要的487.ethical—ethics 道德的488.even ly 均匀的489.eventual ly =in the end最终的490.evolutio nary—evolve 进化的，发展的—进化，发展491.exaggerat ion 夸张492.exceed 超过except for—except ion—exception al 除了—例外—格外的493.excessive过多的，过度的494.ex change交换，交流495.executive行政管理的（人员）496.exemplify 举例说明497.exercise 行使498.exert 强加499.exhaust 耗尽500.exotic 来自外国的501.expan sion 扩充502.expect ation 期望503.expla natory 解释性的504.explicit ly 明确地505.exploit ation 开发、利用506.explos ion—explosive 爆炸—爆炸性的507.expose—expos ure暴露508.express ive表达能力强的；富有表现力的509.extend—extend ed family 延伸—大家庭510.ex ternal外部的511.extinct灭绝512.extinguish熄灭513.extravagantly奢侈的514.fabric结构515.fabricate锻造，伪造516.fact ual事实的；真实的517.faculty才能；教职工；学院518.fade—fad ing 褪色，逐渐消失519.faith fully 忠诚地；忠实地520.fall short of 不足521.fall victim to 成为牺牲品522.fame 名声523.fanci ful—fancy富于幻想的—想象524.far from一点也不525.farfetched牵强的；夸张的526.far-reaching（影响）深远的527.fascinat ion魅力528.fashion 时尚529.fat 丰厚的530.fatal 致命的531.feature特色532.federal联邦制的533.fertile肥沃的；多产的534.fever ishly心急如焚的535.fiction小说536.fierce强烈的537.figure数字538.finance 财政；提供资金539.find fault with挑剔540.finite 有限的541.fix 修理；固定542.flat 扁平的；断然的543.flaw 瑕疵；缺陷544.flee =escape 逃跑545.float 漂浮546.flourish繁荣；昌盛；兴旺547.fluctuate波动548.focus 焦点549.for the sake of为了…的缘故550.forbid禁止551.force fully—force强有力地—力552.formulate —formulation制订；确切表达—公式；确切表达553.forsake 放弃554.fortune 运气；发财555.forum 论坛556.fraction 一部分557.frame 框架558.freight （运输）货物559.frenzy 极度狂热560.frequent ly 经常561.frown 皱眉；反对562.fruit ful—fruitless 富有成果的563.frustrate—frustrat ion 挫败564.fuel 燃料；加燃料，促进565.fulfill 实现566.function—function al 功能；起作用567.further 进一步；推进568.futur ist 未来学家569.gamble 赌博570.gender 性别571.general ization 归纳572.gene rate—generat ion—genetic ally 产生—代—从基因来看573.geological—geology 地理的—地理学574.get stuck 卡住，陷入不动575.giant 巨大的576.gigantic 巨大的577.give birth to 产生，导致578.give rise to 产生，导致579.give thought to 考虑某事580.glimpse 一瞥581.global ization 全球化582.gloomy 阴郁的；不景气的583.glowing 热烈的584.go off 变质/ 爆炸585.gold rush 淘金热586.good-for-nothing 无用的人587.good ness 善良，美德，精华ern 统治589.grand 宏伟的590.granted 被批准的591.graph 图表592.grasp 抓住；理解593.gravity 重力594.greedy 贪婪的595.griev ance 悲痛596.grip 紧抓住597.gross 总的598.guarantee 保证，担保；质保599.guard against 防御，抵制，防止600.guid ance—guide line 指导—指南601.guilt y 有罪的；内疚的602.habit ual 习惯性的603.halve (half) 对半分；减半604.handicap 残疾；不足605.handle = deal with 处理606.harbor 港口；庇护607.harmoni ous 和谐的608.harness 利用609.hasten 使匆忙610.haunt 萦绕611.have one’s way 自有一套612.head line 头条613.head-scratch ing 令人头疼的614.heavi ly 程度深地615.heighten 提高616.heritage 遗产（文化）617.hesitate 犹豫618.high light 强调619.hinder 阻碍620.histor ian 历史学家621.hold back 阻止；抑制；克制622.hold on 坚持623.hook 钩子；钩住624.horizon 地平线；眼界；（知识的）范围625.horrify 令人害怕626.hospitality 好客627.host 男主人；男主持人628.hostil ity—hostile 敌意629.house hold 家庭630.human e—human ity 仁慈的—人性631.humble 谦卑的，谦恭的632.humiliation 不光彩；耻辱633.husbandry 农牧业634.hyper active 多动的635.identical 一模一样的636.identif iable—identify识别；辨别637.ideology 意识形态638.ignor ance—ignor ant 无知；不知道639.ill-treat 虐待640.illuminating 富有启发性的641.illustrate 举例说明642.imagin ation—imagi native 想象力—富有想象力的643.imitate 模仿644.immense 巨大的645.immigrant 移民646.im moral 不道德的647.immune to —immun ization对…有免疫力—不受影响648.impact （深远的）影响649.im part ial 公正的，不偏袒的650.im patien t 不耐烦的651.imperative 必要的，强制性的652.impetus 推动；刺激；促进653.implement ation 实施654.impli cation 外之意655.implicit 暗示的656.im polite 不礼貌的657.impose 强加658.im pover ished 使贫困659.im practical 不切实际的660.im prison 囚禁661.im proper 不恰当的662.im pulse冲动；刺激；推动力663.in brief 总而言之664.in case 万一665.in contrast with/to 和…形成对比、相反666.in despair 绝望地667.in effect =in fact 事实上668.in favor of 支持，赞成669.in honor of 为了纪念…;为了表示敬意670.in no time 立刻；马上671.in no way 不同意672.in one wave after another 一批接一批673.in proportion (to)和…成比例674.in quest of 寻求，搜寻675.in question 正被考虑或讨论676.in return 作为回报677.in the face of 面对某事；不顾678.in the light of 鉴于，考虑到。

2014年考研英语（一）真题超精解【电子版】

2014年考研英语（⼀）真题超精解【电⼦版】丁晓钟：考研英语历年真题超精解 · 2014年2014年全国硕⼠研究⽣⼊学统⼀考试英语(⼀)试题Section I : Use of EnglishDirections:Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on the ANSWER SHEET. (10 points)As many people hit middle age, they often start to notice that their memory and mental clarity are not what they used to be. We suddenly can’t remember 1 we put the keys just a moment ago, or an old acquaintance’s name, or the name of an old band we used to love. As the brain 2 , we refer to these occurrences as “senior moments.”3 seemingly innocent, this loss of mental focus can potentially have a(n)4 impact on our professional, social, and personal5 .Neuroscientists, experts who study the nervous system, are increasingly showing that there’s actually a lot that can be done. It 6 out that the brain needs exercise in much the same way our muscles do, and the right mental 7 can significantly improve our basic cognitive 8 . Thinking is essentially a 9 of making connections in the brain. To a certain extent, our ability to 10 in making the connections that drive intelligence is inherited.11 , because these connections are made through effort and practice, scientists believe that intelligence can expand and fluctuate 12 mental effort.Now, a new Web-based company has taken it a step 13 and developed the first “brain training program” designed to actually help people improve and regain their mental 14 .The Web-based program 15 you to systematically improve your memory and attention skills. The program keeps 16 of your progress and provides detailed feedback 17 your performance and improvement. Most importantly, it 18 modifies and enhances the games you play to 19 on the strengths you are developing — much like a(n) 20 exercise routine requires you to increase resistance and vary your muscle use.1. [A] where [B] when [C] that [D] why2. [A] improves [B] fades [C] recovers [D] collapses3. [A] If [B] Unless [C] Once [D] While4. [A] uneven [B] limited [C] damaging [D] obscure5. [A] wellbeing [B] environment [C] relationship [D] outlook6. [A] turns [B] finds [C] points [D] figures7. [A] roundabouts [B] responses [C] workouts [D] associations8. [A] genre [B] functions [C] circumstances [D] criterion9. [A] channel [B] condition [C] sequence [D] process10. [A] persist [B] believe [C] excel [D] feature11. [A] Therefore [B] Moreover [C] Otherwise [D] However12. [A] according to [B] regardless of [C] apart from [D] instead of13. [A] back [B] further [C] aside [D] around14. [A] sharpness [B] stability [C] framework [D] flexibility15. [A] forces [B] reminds [C] hurries [D] allows16. [A] hold [B] track [C] order [D] pace17. [A] to [B] with [C] for [D] on18. [A] irregularly [B] habitually [C] constantly [D] unusually19. [A] carry [B] put [C] build [D] take20. [A] risky [B] effective [C] idle [D] familiar- 1 -丁晓钟：考研英语历年真题超精解 · 2014年Section II : Reading ComprehensionPart ADirections: Read the following four texts. Answer the questions below each text by choosing A, B, C or D. Mark your answers on the ANSWER SHEET. (40 points)Text 1In order to “change lives for the better” and reduce “dependency,” George Osborne, Chancellor of the Exchequer, introduced the “upfront work search” scheme. Only if the jobless arrive at the job centre with a CV, register for the online job search, and start looking for work will they be eligible for benefit — and then they should report weekly rather than fortnightly. What could be more reasonable?More apparent reasonableness followed. There will now be a seven-day wait for the jobseeker's allowance. “Those first few days should be spent looking for work, not looking to sign on.” he claimed, “We’re doing these things because we know they help people stay off benefits and help those on benefits get into work faster.” Help? Really? On first hearing, this was the socially concerned chancellor, trying to change lives for the better, complete with “reforms” to an obviously indulgent system that demands too little effort from the newly unemployed to find work, and subsidises laziness. What motivated him, we were to understand, was his zeal for “fundamental fairness” — protecting the taxpayer, controlling spending and ensuring that only the most deserving claimants received their benefits.Losing a job is hurting: you don’t skip down to the job centre with a song in your heart, delighted at the prospect of doubling your income from the generous state. It is financially terrifying, psychologically embarrassing and you know that support is minimal and extraordinarily hard to get. You are now not wanted; you are now excluded from the work environment that offers purpose and structure in your life. Worse, the crucial income to feed yourself and your family and pay the bills has disappeared. Ask anyone newly unemployed what they want and the answer is always: a job.But in Osborneland, your first instinct is to fall into dependency — permanent dependency if you can get it — supported by a state only too ready to indulge your falsehood. It is as though 20 years of ever-tougher reforms of the job search and benefit administration system never happened. The principle of British welfare is no longer that you can insure yourself against the risk of unemployment and receive unconditional payments if the disaster happens. Even the very phrase “jobseeker’s allowance” is about redefining the unemployed as a “jobseeker” who had no fundamental right to benefit he or she has earned through making national insurance contributions. Instead, the claimant receives a time-limited “allowance,”conditional on actively seeking a job: no entitlement and no insurance, at ?71.70 a week, one of the least generous in the EU.21. George Osborne’s scheme was intended to[A] provide the unemployed with easier access to benefits.[B] encourage jobseekers’ active engagement in job seeking.[C] motivate the unemployed to report voluntarily.[D] guarantee jobseekers’ legitimate right to benefits.22. The phase “to sigh on”(Line 2, Para. 2) most probably means[A] to check on the availability of jobs at the jobcentre.[B] to accept the government’s restrictions on the allowance.[C] to register for an allowance from the government.[D] to attend a governmental job-training program.- 2 -丁晓钟：考研英语历年真题超精解 · 2014年23. What prompted the chancellor to develop his scheme?[A] A desire to secure a better life for all. [B] An eagerness to protect the unemployed.[C] An urge to be generous to the claimants. [D] A passion to ensure fairness for taxpayers.24. According to Paragraph 3, being unemployed makes one feel[A] uneasy. [B] enraged. [C] insulted. [D] guilty.25. To which of the following would the author most probably agree?[A] The British welfare system indulges jobseekers’ laziness.[B] Osborne’s reform will reduce the risk of unemployment.[C] The jobseekers’ allowance has met their actual needs.[D] Unemployment benefits should not be made conditional.Text 2All around the world, lawyers generate more hostility than the members of any other profession — with the possible exception of journalism. But there are few places where clients have more grounds for complaint than America.During the decade before the economic crisis, spending on legal services in America grew twice as fast as inflation. The best lawyers made skyscrapers-full of money, tempting ever more students to pile into law schools. But most law graduates never get a big-firm job. Many of them instead become the kind of nuisance-lawsuit filer that makes the tort system a costly nightmare.There are many reasons for this. One is the excessive costs of a legal education. There is just one path for a lawyer in most American states; a four-year undergraduate degree in some unrelated subject, then a three-year law degree at one of 200 law schools authorized by the American Bar Association and an expensive preparation for the bar exam. This leaves today’s average law-school graduate with $100,000 of debt on top of undergraduate debts. Law-school debt means that they have to work fearsomely hard.Reforming the system would help both lawyers and their customers. Sensible ideas have been around for a long time, but the state-level bodies that govern the profession have been too conservative to implement them. One idea is to allow people to study law as an undergraduate degree. Another is to let students sit for the bar after only two years of law school. If the bar exam is truly a stern enough test for a would-be lawyer, those who can sit it earlier should be allowed to do so. Students who do not need the extra training could cut their debt mountain by a third.The other reason why costs are so high is the restrictive guild-like ownership structure of the business. Except in the District of Columbia, non-lawyers may not own any share of a law firm. This keeps fees high and innovation slow. There is pressure for change from within the profession, but opponents of change among the regulators insist that keeping outsiders out of a law firm isolates lawyers from the pressure to make money rather than serve clients ethically.In fact, allowing non-lawyers to own shares in law firms would reduce costs and improve services to customers, by encouraging law firms to use technology and to employ professional managers to focus on improving firms’ efficiency. After all, other countries, such as Australia and Britain, have started liberalizing their legal professions. America should follow.26. A lot of students take up law as their profession due to[A] the growing demand from clients. [B] the increasing pressure of inflation.[C] the prospect of working in big firms. [D] the attraction of financial rewards.27. Which of the following adds to the costs of legal education in most American states?[A] Higher tuition fees for undergraduate studies. [B] Admissions approval from the bar association.[C] Pursuing a bachelor’s degree in another major. [D] Receiving training by professional associations.- 3 -丁晓钟：考研英语历年真题超精解 · 2014年28. Hindrance to the reform of the legal system originates from[A] lawyers’ and clients’ strong resistance. [B] the rigid bodies governing the profession.[C] the stern exam for would-be lawyers. [D] non-professionals’ sharp criticism.29. The guild-like ownership structure is considered “restrictive” partly because it[A] bans outsiders’ involvement in the profession. [B] keeps lawyers form holding law-firm shares.[C] aggravates the ethical situation in the trade. [D] prevents lawyers from gaining due profits.30. In this text, the author mainly discusses[A] flawed ownership of America’s law firms and its causes.[B] the factors that help make a successful lawyer in America.[C] a problem in America’s legal profession and solutions to it.[D] the role of undergraduate studies in America’s legal education.Text 3The US$3-million Fundamental Physics Prize is indeed an interesting experiment, as Alexander Polyakov said when he accepted this year’s award in March. And it is far from the only one of its type. As a News Feature article in Nature discusses, a string of lucrative awards for research have joined the Nobel Prizes in recent years.Many, like the Fundamental Physics Prize, are funded from the telephone-number-sized bank accounts of Internet entrepreneurs. These benefactors have succeeded in their chosen fields, they say, and they want to use their wealth to draw attention to those who have succeeded in science.What’s not to like? Quite a lot, according to a handful of scientists quoted in the News Feature. You cannot buy class, as the old saying goes, and these upstart entrepreneurs cannot buy their prizes the prestige of the Nobels. The new awards are an exercise in self-promotion for those behind them, say scientists. They could distort the achievement-based system of peer-review-led research. They could cement the status quo of peer-reviewed research. They do not fund peer-reviewed research. They perpetuate the myth of the lone genius.The goals of the prize-givers seem as scattered as the criticism. Some want to shock, others to draw people into science, or to better reward those who have made their careers in research.As Nature has pointed out before, there are some legitimate concerns about how science prizes — both new and old — are distributed. The Breakthrough Prize in Life Sciences, launched this year, takes an unrepresentative view of what the life sciences include. But the Nobel Foundation’s limit three recipients per prize, each of whom must still be living,has long been outgrown by the collaborative nature of modern research— as will be demonstrated by the inevitable row over who is ignored when it comes to acknowledging the discovery of the Higgs boson. The Nobels were, of course, themselves set up by a very rich individual who had decided what he wanted to do with his own money. Time, rather than intention, has given them legitimacy.As much as some scientists may complain about the new awards, two things seem clear. First, most researchers would accept such a prize if they were offered one.Second, it is surely a good thing that the money and attention come to science rather than go elsewhere. It is fair to criticize and question the mechanism — that is the culture of research, after all — but it is the prize-givers’ money to do with as they please. It is wise to take such gifts with gratitude and grace.31. The Fundamental Physics Prize is seen as[A] a symbol of the entrepreneurs’ wealth. [B] a possible replacement of the Nobel Prizes.[C] an example of bankers’ investments. [D] a handsome reward for researchers.32. The critics think that the new awards will most benefit[A] the profit-oriented scientists. [B] the founders of the new awards.[C] the achievement-based system. [D] peer-review-led research.- 4 -丁晓钟：考研英语历年真题超精解 · 2014年33. The discovery of the Higgs boson is a typical case which involves[A] controversies over the recipients’ status. [B] the joint effort of modern researchers.[C] legitimate concerns over the new prizes. [D] the demonstration of research findings.34. According to Paragraph 4, which of the following is true of the Nobels?[A] Their endurance has done justice to them. [B] Their legitimacy has long been in dispute.[C] They are the most representative honor. [D] History has never cast doubt on them.35. The author believes that the new awards are[A] acceptable despite the criticism. [B] harmful to the culture of research.[C] subject to undesirable changes. [D] unworthy of public attention.Text 4“The Heart of the Matter,” the just-released report by the American Academy of Arts and Sciences (AAAS), deserves praise for affirming the importance of the humanities and social sciences to the prosperity and security of liberal democracy in America. Regrettably, however, the report’s failure to address the true nature of the crisis facing liberal education may cause more harm than good.In 2010, leading congressional Democrats and Republicans sent letters to the AAAS asking that it identify actions that could be taken by “federal, state and local governments, universities, foundations, educators, individual benefactors and others”to “maintain national excellence in humanities and social scientific scholarship and education.” In response, the American Academy formed the Commission on the Humanities and Social Sciences. Among the commission’s 51 members are top-tier-university presidents, scholars, lawyers, judges, and business executives, as well as prominent figures from diplomacy, filmmaking, music and journalism.The goals identified in the report are generally admirable. Because representative government presupposes an informed citizenry, the report supports full literacy; stresses the study of history and government, particularly American history and American government; and encourages the use of new digital technologies. To encourage innovation and competition, the report calls for increased investment in research, the crafting of coherent curricula that improve students’ ability to solve problems and communicate effectively in the 21st century, increased funding for teachers and the encouragement of scholars to bring their learning to bear on the great challenges of the day. The report also advocates greater study of foreign languages, international affairs and the expansion of study-abroad programs.Unfortunately, despite 2? years in the making, “The Heart of the Matter” never gets to the heart of the matter: the illiberal nature of liberal education at our leading colleges and universities. The commission ignores that for several decades America’s colleges and universities have produced graduates who don’t know the content and character of liberal education and are thus deprived of its benefits. Sadly, the spirit of inquiry once at home on campus has been replaced by the use of the humanities and social sciences as vehicles for publicizing “progressive,” or left-liberal propaganda.Today, professors routinely treat the progressive interpretation of history and progressive public policy as the proper subject of study while portraying conservative or classical liberal ideas — such as free markets and self-reliance — as falling outside the boundaries of routine, and something legitimate, intellectual investigation.The AAAS displays great enthusiasm for liberal education. Yet its report may well set back reform by obscuring the depth and breadth of the challenge that Congress asked it to illuminate.36. According to Paragraph 1, what is the author’s attitude toward the AAAS’s report?[A] Critical. [B] Appreciative. [C] Contemptuous. [D] Tolerant.37. Influential figures in the Congress required that the AAAS report on how to- 5 -丁晓钟：考研英语历年真题超精解 · 2014年[A] retain people’s interest in liberal education. [B] define the government’s role in education.[C] keep a leading position in liberal education. [D] safeguard individuals’ rights to education.38. According to paragraph 3, the report suggests[A] an exclusive study of American history. [B] a greater emphasis on theoretical subjects.[C] the application of emerging technologies. [D] funding for the study of foreign languages.39. The author implies in paragraph 5 that professors are[A] supportive of free markets. [B] cautious about intellectual investigation.[C] conservative about public policy. [D] biased against classical liberal ideas.40. Which of the following would be the best title for the text?[A] Ways to Grasp “The Heart of the Matter” [B] Illiberal Education and “The Heart of the Matter”[C] The AAAS’s Contribution to Liberal Education [D] Progressive Policy vs. Liberal EducationPart BDirections: The following paragraphs are given in a wrong order. For Questions 41-45, you are required to reorganize these paragraphs into a coherent text by choosing from the list A-G and filling them into thenumbered boxes. Paragraphs A and E have been correctly placed. Mark your answers on the ANSWERSHEET. (10 points)[A] Some archaeological sites have always been easily observable — for example, the Parthenon in Athens, Greece;the pyramids of Giza in Egypt; and the megaliths of Stonehenge in southern England. But these sites are exceptions to the norm. Most archaeological sites have been located by means of careful searching, while many others have been discovered by accident. Olduvai Gorge, an early hominid site in Tanzania, was found by a butterfly hunter who literally fell into its deep valley in 1911. Thousands of Aztec artifacts came to light during the digging of the Mexico City subway in the 1970s.[B] In another case, American archaeologists René Million and George Cowgill spent years systematically mappingthe entire city of Teotihuacan in the Valley of Mexico near what is now Mexico City. At its peak around AD 600, this city was one of the largest human settlements in the world. The researchers mapped not only the city’s vast and ornate ceremonial areas, but also hundreds of simpler apartment complexes where common people lived. [C] How do archaeologists know where to find what they are looking for when there is nothing visible on the surfaceof the ground? Typically, they survey and sample (make test excavations on) large areas of terrain to determine where excavation will yield useful information. Surveys and test samples have also become important for understanding the larger landscapes that contain archaeological sites[D] Surveys can cover a single large settlement or entire landscapes. In one case, many researchers working aroundthe ancient Maya city of Copán, Honduras, have located hundreds of small rural villages and individual dwellings by using aerial photographs and by making surveys on foot. The resulting settlement maps show how the distribution and density of the rural population around the city changed dramatically between AD 500 and 850, when Copán collapsed.[E] To find their sites, archaeologists today rely heavily on systematic survey methods and a variety ofhigh-technology tools and techniques. Airborne technologies, such as different types of radar and photographic equipment carried by airplanes or spacecraft, allow archaeologists to learn about what lies beneath the ground without digging. Aerial surveys locate general areas of interest or larger buried features, such as ancient buildings or fields.[F] Most archaeological sites, however, are discovered by archaeologists who have set out to look for them. Suchsearches can take years. British archaeologist Howard Carter knew that the tomb of the Egyptian pharaoh Tutankhamun existed from information found in other sites. Carter sifted through rubble in the Valley of the- 6 -丁晓钟：考研英语历年真题超精解 · 2014年Kings for seven years before he located the tomb in 1922. In the late 1800s British archaeologists Sir Arthur Evans combed antique dealers’ stores in Athens, Greece. He was searching for tiny engraved seals attributed to the ancient Mycenaean culture that dominated Greece from the 1400s to 1200s BC. Evans’s interpretations of these engravings eventually led him to find the Minoan palace at Knossos (Knosos), on the island of Crete, in 1900.[G] Ground surveys allow archaeologists to pinpoint the places where digs will be successful. Most ground surveysinvolve a lot of walking, looking for surface clues such as small fragments of pottery. They often include a certain amount of digging to test for buried materials at selected points across a landscape. Archaeologists also may locate buried remains by using such technologies as ground radar, magnetic-field recording, and metal detectors. Archaeologists commonly use computers to map sites and the landscapes around sites. Two- and three-dimensional maps are helpful tools in planning excavations, illustrating how sites look, and presenting the results of archaeological research.41. → A → 42. → E → 43. → 44. →45.Section III : TranslationDirections: Read the following text carefully and then translate the underlined segments into Chinese. Your translation should be written neatly on the ANSWER SHEET. (10 points)Music means different things to different people and sometimes even different things to the same person at different moments of his life. It might be poetic, philosophical, sensual, or mathematical, but in any case it must, in my view, have something to do with the soul of the human being. Hence it is metaphysical; but the means of expression is purely and exclusively physical: sound. I believe it is precisely this permanent coexistence of metaphysical message through physical means that is the strength of music. (46) It is also the reason why when we try to describe music with words, all we can do is articulate our reactions to it, and not grasp music itself.Beethoven’s importance in music has been principally defined by the revolutionary nature of his compositions. He freed music from hitherto prevailing conventions of harmony and structure. Sometimes I feel in his late works a will to break all signs of continuity. The music is abrupt and seemingly disconnected, as in the last piano sonata. In musical expression, he did not feel restrained by the weight of convention. (47) By all accounts he was a freethinking person, and a courageous one, and I find courage an essential quality for the understanding, let alone the performance, of his works.This courageous attitude in fact becomes a requirement for the performers of Beethoven’s music. His compositions demand the performer to show courage, for example in the use of dynamics. (48) Beethoven’s habit of increasing the volume with an extreme intensity and then abruptly following it with a sudden soft passage was only rarely used by composers before him. Beethoven was a deeply political man in the broadest sense of the word. He was not interested in daily politics, but concerned with questions of moral behaviour and the larger questions of right and wrong affecting the entire society. (49) Especially significant was his view of freedom, which, for him, was associated with the rights and responsibilities of the individual: he advocated freedom of thought and of personal expression.Beethoven’s music tends to move from chaos to order as if order were an imperative of human existence. For him, order does not result from forgetting or ignoring the disorders that plague our existence; order is a necessary development, an improvement that may lead to the Greek ideal of spiritual elevation. It is not by chance that the Funeral March is not the last movement of the Eroica Symphony, but the second, so that suffering does not have the last word. (50) One could interpret much of the work of Beethoven by saying that suffering is inevitable, but the courage to fight it renders life worth living.- 7 -丁晓钟：考研英语历年真题超精解 · 2014年- 8 -Section IV : WritingPart A51. Directions:Write a letter of about 100 words to the president of your university, suggesting how to improve students’ physical condition. You should include the details you think necessary.You should write neatly on the ANSWER SHEET.Do not sign your own name at the end of the letter. Use “Li Ming” instead.Do not write the address. (10 points)Part B52. Directions:Write an essay of 160-200 words based on the following drawing. In your essay you should1) describe the drawing briefly,2) explain its intended meaning, and3) give your comments.You should write neatly on the ANSWER SHEET. (20 points)【参考答案】Section I : Use of English1. [A]2. [B]3. [D]4. [C]5. [A]6. [A]7. [C]8. [B]9. [D] 10. [C]11. [D] 12. [A] 13. [B]14. [A] 15. [D] 16. [B]17. [D]18. [C]19. [C] 20. [B]Section II : Reading ComprehensionPart A21. [B] 22. [C] 23. [D]24. [A] 25. [D] 26. [D]27. [C]28. [B]29. [A] 30. [C]31. [D] 32. [B] 33. [B]34. [A] 35. [A] 36. [A]37. [C]38. [C]39. [D] 40. [B]Part B41. [C] 42. [F] 43. [G]44. [D] 45. [B]丁晓钟：考研英语历年真题超精解 · 2014年- 9 -Section I : Use of English{⼀} ①As many people hit middle age, they often start to notice that their memory and mental clarity are not what they used to be. ②We suddenly can’t remember 1 where we put the keys just a moment ago, or an old acquaintance’s name, or the name of an old band we used to love. ③As the brain 2 fades , we refer to these occurrences as “senior moments.” ④ 3 While seemingly innocent, this loss of mental focus can potentially have a 4 damaging impact on our professional, social, and personal 5 wellbeing . ①很多⼈到了中年，会经常发现⾃⼰的记忆⼒和思维清晰度不如以往。

考研英语2006答案解析

其次今年的阅读理解给我们导航的反馈不一样。有很多人说今年的阅读好难，虽然今年的间接题很多，但是你会发现以往都会暗示作者推断什么，今年也出现暗示和推论但一定把范围缩小，会给你一些专有名词数字等等。
今年在阅读B这一块开了一个很大的玩笑，原先的题目设计不知道是怎么样的，但有一点从十一月份各个培训学校的老师，包括北京东方导航的老师在各大网站进行预测的时候都从测试学的角度认为今年出这个新题型是考排序题，所以今年刚好把这个颠过来了，虽然只有十分，但是我们可以认为这个题在十一月份会被换掉，而且我在考试之前还提到由于我们的评分标准不统一，所以在这一块还有争议，到底是五个空全部排列完整得分，还是部分排列得分。今天拿到7选5很多同学比较担心，但今年的7选5确实比去年难度有所降低，去年的文章有一个A选项，这个A选和文章当中的很多段落有关系。我们做阅读B考察的是在相对比较小的语言环境当中讨论的主题对象只有一个，所以我们可以在各个段落找到不同的要点，把空前面和后面的东西与ABCD选项的文章进行对应，而没有必要全部把文章读完。今年比较明显的单词对应要干净的多。我甚至都逼着同学说，你41、42、43都想选的话那一定是老师设计出来的干扰项，而今年这样的现象就不再存在。
郑景婷：第二篇文章里面主要是讲的莎士比亚的故居，它的问题是旅游给我们带来的问题。在第四篇文章里面比较抽象，同学普遍反应这一篇文章比较难，讲到了社会科学方面，讲到了艺术的各种形式在表达形式上有横向和纵向的比较。题材并不是最重要的，最主要的是今天英语考完之后有两种看法，一个觉得很难，一个是觉得今年阅读没有很难的地方。从总体来说我们的考生应当把我们的注意力集中到我们的题干以及题目干扰项的设计上。
while这个词是当的意思，此外它还有尽管的意思，所以如果你“尽管”的意思出不来的话，问题会比较严重一些，所以这个词要注意一下。还有大家说到了Contribut原来是贡献，在这里是促成的意思。在第四个句子里面难度很高，不仅有插入语，而且还有变相的比较级的比较否定，如果你看不出来这一块会比较麻烦，这一块大概会占到1分。当然前面四个句子都比较难，最后一个句子比较简单一些，最后一个句子有预期上的调度和调整，要么就是根本没有。其实我们都可以预测到，它的这个翻译，每次必考的就是这些，有词意的选择，有代词，有比较级，有被动语态，有倒装句，这就是今年的翻译，在难以程度和翻译上没有什么新意。基本上是一个句子难一个句子简单，难度比较充分。

新世纪研究生公共英语教材阅读B课后答案

UNIT ONE Party PoliticsP8 I Comprehension Check1-5 DCDAB 6-10 DDCABP10 V ocabulary StudyI 1-5 CBADB 6-10 CDBCDII 1.etiquette 2.looped 3.unaccountable 4.told off 5. conspicuously 6. pesky 7.let loose 8.racy 9.murky 10.ticklishIII TranslationP14 Key to Supplementary ReadingsA.1-5 FFFTT 6-10 FTFTTB.1-5 FTFTF 6-10 FTFTFUNIT TWO The New SinglesP29 I Comprehension Check1-5 BDBDC 6-10 ACCADP31 V ocabulary StudyI 1.neo-realist 2.neo-Nazis 3.Neo-fascist 4.neocolonialism 5. neologisms 6.neo-Darwinist7.neoclassical 8. neonatesII 1.fostering 2.reaved 3.holy grail 4.mainstay 5.twenty-somethings 6.heterosexuals 7.mandatory 8.embracing 9.meditating 10.fusionIII TranslationKey to Supplementary Readings(略)UNIT THREE Doctor’s Dilemma:Treat or Let Die?P51 Comprehension Check1-5 BCCBD 6-10 DCDADP53 V ocabulary StudyI 1.outstrip 2.limbo 3.ceased 4. in the wake of 5. paramount 6.ethical 7.prolonged 8. thorny9.congenital 10.subsequentlyII 1.euthanasia 2.salvaged 3.deformity 4.defects 5. handicaps 6.lingering 7. grapple 8. allegedly 9.acquitted 10.frontiersIII TranslationP59 Key to Supplementary ReadingsA.1-5 FTFTF 6-10 TTTFTB.1-5 FFTTF 6-10 TFTFFUNIT FOUR The Cultural Patterning of SpaceP71 Comprehension Check1-5 BABCC 6-9 DDDBP73 V ocabulary StudyI 1-5 begja 6-10 hcifdII 1.anthropologists 2. Patterns 3.tangible 4. persistent 5. infringe 6. integrate 7. secular 8. spatial9.florist’s 10.ArchitectureIII TranslationUNIT FIVE Can Y ou Raise a Polite Kid in This Rude World?P94 Comprehension Check1-5 BDADB 6-9 AADBP95 V ocabulary StudyI 1-5 deigj 6-10 hfabcII 1.provocative 2. notional 3. curb 4.devastating 5. appalling 6.perspective 7. counterpart 8. fray 9.defuse 10.frustratedIII TranslationUNIT SIX The New American DreamersP115 Comprehension Check1-5 DEAAC 6-10 DCDABP117 V ocabulary StudyI outgoing 2.petite 3.emphatically 4.self-possessed 5. quest 6.personable 7. fantasized 8. buy into9.defer 10.caught upII 1.involved 2. committed 3. figure out 4. convinced 5.affluent 6. tied down 7. quest 8. the end of the rainbow 9.therapeutic 10. formulatingIII TranslationP126 Key to Supplementary ReadingsA.1-5 CCBDD 6-8 AAAB.1-5 FFFTF 6-10 TTTFTUNIT SEVEN A Son’s Restless JourneyP143 Comprehension Check1-5 ABDCB 6-8 DABP144 V ocabulary StudyI 1.carped 2. embodied 3. agonized 4. outright 5. peered 6.mediocre 7. inundated 8. bucked 9. snarling at 10.petered outII 1.obsolete 2.wince 3.grueling 4. whizzed through 5. pretentious 6.squelched 7.mull 8. jaded 9. misgivings 10. sanctuary 11.unfazed 12.posed 13.scoffed 14. misbehavedIII TranslationP150 Key to Supplementary ReadingsA.1-5 DCCDB 6-10 ABAABB. 1-5 FTFTF 6-10 FTTFF 11-15 TTFFFUNIT EIGHT Sex RolesP169 Comprehension Check1-5 DCABA 6-10 CCBADP171 V ocabulary StudyI 1-5 jhgab 6-10 idcfeII 1. aggressive 2. stereotyped 3. inhibit 4. masculine 5.disapproval 6.subsistence 7. speculate 8.perceive 9. socialize 10.proneIII TranslationP181 Key to Supplementary ReadingsA.B.1-5 TFFTT 6-9 TFTTUNIT NINE Animal EmotionsP193 Comprehension Check1-5 DADCC 6-10 BBACDP195 V ocabulary StudyI 1. parlance 2. stringent 3. ascribed 4. symposium 5. copious 6. aversion to 7. warrant 8. manipulated 9. garnered 10.lingeredII 1. hormones 2. predators 3.elated 4. elicited 5. entail 6. anecdotes 7. controversial 8. legitimize 9. wake 10.dejectedlyIII TranslationP200 Key to Supplementary ReadingsA.1-5 TTTTF 6-10 FTFFTB.1-5 TFFTT 6-10 FFTFTUNIT TEN Is Science Dangerous?P214 Comprehension Check1-5 BBDAC 6-10 BCADBP216 V ocabulary StudyI 1.standing by 2. conjured up 3. cherishes 4. stick to 5. shoulder 6. siblings 7. came by 8. dressing up 9.tyranny 10. come into playII 1. reverberates 2. appropriate 3. dispassionately 4. emphatically 5. rationed 6. enlightened 7. proscribed 8. blameworthy 9. confidentiality 10. implicationIII TranslationP222 Key to Supplementary ReadingsA.1-5 TTFFT 6-10 TFTTTB. 1-5 TFFFT 6-10 TFFFT2013 C类安全员复习判断单选多选案例——案例题1. C类对负责人处罚1、企业是安全生产管理的主体。

1-2007_-_Y_F_Han_-_PreparationofnanosizedMn3O4SBA15catalystforcomplet[retrieved-2016-11-15]

Preparation of nanosized Mn 3O 4/SBA-15catalyst for complete oxidation of low concentration EtOH in aqueous solution with H 2O 2Yi-Fan Han *,Fengxi Chen,Kanaparthi Ramesh,Ziyi Zhong,Effendi Widjaja,Luwei ChenInstitute of Chemical and Engineering Sciences,1Pesek Road,Jurong Island 627833,Singapore Received 11May 2006;received in revised form 18December 2006;accepted 29May 2007Available online 2June 2007AbstractA new heterogeneous Fenton-like system consisting of nano-composite Mn 3O 4/SBA-15catalyst has been developed for the complete oxidation of low concentration ethanol (100ppm)by H 2O 2in aqueous solution.A novel preparation method has been developed to synthesize nanoparticles of Mn 3O 4by thermolysis of manganese (II)acetylacetonate on SBA-15.Mn 3O 4/SBA-15was characterized by various techniques like TEM,XRD,Raman spectroscopy and N 2adsorption isotherms.TEM images demonstrate that Mn 3O 4nanocrystals located mainly inside the SBA-15pores.The reaction rate for ethanol oxidation can be strongly affected by several factors,including reaction temperature,pH value,catalyst/solution ratio and concentration of ethanol.A plausible reaction mechanism has been proposed in order to explain the kinetic data.The rate for the reaction is supposed to associate with the concentration of intermediates (radicals: OH,O 2Àand HO 2)that are derived from the decomposition of H 2O 2during reaction.The complete oxidation of ethanol can be remarkably improved only under the circumstances:(i)the intermediates are stabilized,such as stronger acidic conditions and high temperature or (ii)scavenging those radicals is reduced,such as less amount of catalyst and high concentration of reactant.Nevertheless,the reactivity of the presented catalytic system is still lower comparing to the conventional homogenous Fenton process,Fe 2+/H 2O 2.A possible reason is that the concentration of intermediates in the latter is relatively high.#2007Elsevier B.V .All rights reserved.Keywords:Hydrogen peroxide;Fenton catalyst;Complete oxidation of ethanol;Mn 3O 4/SBA-151.IntroductionRemediation of wastewater containing organic constitutes is of great importance because organic substances,such as benzene,phenol and other alcohols may impose toxic effects on human and animal anic efﬂuents from pharmaceu-tical,chemical and petrochemical industry usually contaminate water system by dissolving into groundwater.Up to date,several processes have been developed for treating wastewater that contains toxic organic compounds,such as wet oxidation with or without solid catalysts [1–4],biological oxidation,supercritical oxidation and adsorption [5,6],etc.Among them,catalytic oxidation is a promising alternative,since it avoids the problem of the adsorbent regeneration in the adsorption process,decreases signiﬁcantly the temperature and pressure in non-catalytic oxidation techniques [7].Generally,the disposalof wastewater containing low concentration organic pollutants (e.g.<100ppm)can be more costly through all aforementioned processes.Thus,catalytic oxidation found to be the most economical way for this purpose with considering its low cost and high efﬁciency.Currently,a Fenton reagent that consists of homogenous iron ions (Fe 2+)and hydrogen peroxide (H 2O 2)is an effective oxidant and widely applied for treating industrial efﬂuents,especially at low concentrations in the range of 10À2to 10À3M organic compounds [8].However,several problems raised by the homogenous Fenton system are still unsolved,e.g.disposing the iron-containing waste sludge,limiting the pH range (2.0–5.0)of the aqueous solution,and importantly irreversible loss of activity of the reagent.To overcome these drawbacks raised from the homogenous Fenton system,since 1995,a heterogeneous Fenton reagent using metal ions exchanged zeolites,i.e.Fe/ZSM-5has proved to be an interesting alternative catalytic system for treating wastewater,and showed a comparable activity with the homogenous Fenton system [9].However,most reported heterogeneous Fenton reagents still need UV radiation during/locate/apcatbApplied Catalysis B:Environmental 76(2007)227–234*Corresponding author.Tel.:+6567963806.E-mail address:han_yi_fan@.sg (Y .-F.Han).0926-3373/$–see front matter #2007Elsevier B.V .All rights reserved.doi:10.1016/j.apcatb.2007.05.031oxidation of organic compounds.This might limit the application of homogeneous Fenton system.Exploring other heterogeneous catalytic system considering the above disadvantages,is still desirable for this purpose.Here,we present an alternative catalytic system for the complete oxidation of organic com-pounds in aqueous solution using supported manganese oxide as catalyst under mild conditions,which has rarely been addressed.Mn-containing oxide catalysts have been found to be very active for the catalytic wet oxidation of organic efﬂuents (CWO)[10–14],which is operated at high air pressures(1–22MPa)and at high temperatures(423–643K)[15].On the other hand,manganese oxide,e.g.MnO2[16],is well known to be active for the decomposition of H2O2in aqueous solution to produce hydroxyl radical( OH),which is considered to be the most robust oxidant so far.The organic constitutes can be deeply oxidized by those radicals rapidly[17].The only by-product is H2O from decomposing H2O2.Therefore,H2O2is a suitable oxidant for treating the wastewater containing organic compounds.Due to the recent progress in the synthesis of H2O2 directly from H2and O2[18,19],H2O2is believed to be produced through more economical process in the coming future.So,the heterogeneous Fenton system is economically acceptable.In this study,nano-crystalline Mn3O4highly dispersed inside the mesoporous silica,SBA-15,has been prepared by thermolysis of organic manganese(II)acetylacetonate in air. We expect the unique mesoporous structure may provide add-itional function(conﬁnement effect)to the catalytic reaction, i.e.occluding/entrapping large organic molecules inside pores. The catalyst as prepared has been examined for the complete oxidation of ethanol in aqueous solution with H2O2,or to say, wet peroxide oxidation.Ethanol was selected as a model organic compound because(i)it is one of the simplest organic compounds and can be easily analyzed,(ii)it has high solu-bility in water due to its strong hydrogen bond with water molecule and(iii)the structure of ethanol is quite stable and only changed through catalytic reaction.Presently,for theﬁrst time by using the Mn3O4/SBA-15catalyst,we investigated the peroxide ethanol oxidation affected by factors such as temperature,pH value,ratio of catalyst(g)and volume of solution(L),and concentration of ethanol in aqueous solution. In addition,plausible reaction mechanisms are established to explain the peroxidation of ethanol determined by the H2O2 decomposition.2.Experimental2.1.Preparation and characterization of Mn3O4/SBA-15 catalystSynthesis of SBA-15is similar to the previous reported method[20]by using Pluronic P123(BASF)surfactant as template and tetraethyl orthosilicate(TEOS,98%)as silica source.Manganese(II)acetylacetonate([CH3COCH C(O)CH3]2Mn,Aldrich)by a ratio of2.5mmol/gram(SBA-15)wereﬁrst dissolved in acetone(C.P.)at room temperature, corresponding to ca.13wt.%of Mn3O4with respect to SBA-15.The preparation method in detail can be seen in our recent publications[21,22].X-ray diffraction proﬁles were obtained with a Bruker D8 diffractometer using Cu K a radiation(l=1.540589A˚).The diffraction pattern was taken in the Bragg angle(2u)range at low angles from0.68to58and at high angles from308to608at room temperature.The XRD patterns were obtained by scanning overnight with a step size:0.028per step,8s per step.The dispersive Raman microscope employed in this study was a JY Horiba LabRAM HR equipped with three laser sources(UV,visible and NIR),a confocal microscope,and a liquid nitrogen cooled charge-coupled device(CCD)multi-channel detector(256pixelsÂ1024pixels).The visible 514.5nm argon ion laser was selected to excite the Raman scattering.The laser power from the source is around20MW, but when it reached the samples,the laser output was reduced to around6–7MW after passing throughﬁltering optics and microscope objective.A100Âobjective lens was used and the acquisition time for each Raman spectrum was approximately 60–120s depending on the sample.The Raman shift range acquired was in the range of50–1200cmÀ1with spectral resolution1.7–2cmÀ1.Adsorption and desorption isotherms were collected on Autosorb-6at77K.Prior to the measurement,all samples were degassed at573K until a stable vacuum of ca.5m Torr was reached.The pore size distribution curves were calculated from the adsorption branch using Barrett–Joyner–Halenda(BJH) method.The speciﬁc surface area was assessed using the BET method from adsorption data in a relative pressure range from 0.06to0.10.The total pore volume,V t,was assessed from the adsorbed amount of nitrogen at a relative pressure of0.99by converting it to the corresponding volume of liquid adsorbate. The conversion factor between the volume of gas and liquid adsorbate is0.0,015,468for N2at77K when they are expressed in cm3/g and cm3STP/g,respectively.The measurements of transmission electron microscopy (TEM)were performed at Tecnai TF20S-twin with Lorentz Lens.The samples were ultrasonically dispersed in ethanol solvent,and then dried over a carbon grid.2.2.Kinetic measurement and analysisThe experiment for the wet peroxide oxidation of ethanol was carried out in a glass batch reactor connected to a condenser with continuous stirring(400rpm).Typically,20ml of aqueous ethanol solution(initial concentration of ethanol: 100ppm)wasﬁrst taken in the round bottomﬂask(reactor) together with5mg of catalyst,corresponding to ca.1(g Mn)/30 (L)ratio of catalyst/solution.Then,1ml of30%H2O2solution was introduced into the reactor at different time intervals (0.5ml at$0min,0.25ml at32min and0.25ml at62min). The total molar ratio of H2O2/ethanol is about400/1. Hydrochloric acid(HCl,0.01M)was used to acidify the solution if necessary.NH4OH(0.1M)solution was used to adjust pH to9.0when investigating the effect of pH.The pH for the deionized water is ca.7.0(Oakton pH meter)and decreased to 6.7after adding ethanol.All the measurements wereY.-F.Han et al./Applied Catalysis B:Environmental76(2007)227–234 228performed under the similar conditions described above if without any special mention.For comparison,the reaction was also carried out with a typical homogenous Fenton reagent[17], FeSO4(5ppm)–H2O2,under the similar reaction conditions.The conversion of ethanol during reaction was detected using gas chromatography(GC:Agilent Technologies,6890N), equipped with HP-5capillary column connecting to a thermal conductive detector(TCD).There is no other species but ethanol determined in the reaction system as evidenced by the GC–MS. Ethanol is supposed to be completely oxidized into CO2and H2O.The variation of H2O2concentration during reaction was analyzed colorimetrically using a UV–vis spectrophotometer (Epp2000,StellarNet Inc.)after complexation with a TiOSO4/ H2SO4reagent[18].Note that there was almost no measurable leaching of Mn ion during reaction analyzed by ICP(Vista-Mpx, Varian).3.Results and discussion3.1.Characterization of Mn3O4/SBA-15catalystThe structure of as-synthesized Mn3O4inside SBA-15has beenﬁrst investigated with powder XRD(PXRD),and the proﬁles are shown in Fig.1.The proﬁle at low angles(Fig.1a) suggests that SBA-15still has a high degree of hexagonal mesoscopic organization even after forming Mn3O4nanocrys-tals[23].Several peaks at high angles of XRD(Fig.1b)indicate the formation of a well-crystallized Mn3O4.All the major diffraction peaks can be assigned to hausmannite Mn3O4 structure(JCPDS80-0382).By N2adsorption measurements shown in Fig.2,the pore volume and speciﬁc surface areas(S BET)decrease from 1.27cm3/g and937m2/g for bare SBA-15to0.49cm3/g and 299m2/g for the Mn3O4/SBA-15,respectively.About7.7nm of mesoporous diameter for SBA-15decreases to ca.6.3nm for Mn3O4/SBA-15.The decrease of the mesopore dimension suggests the uniform coating of Mn3O4on the inner walls of SBA-15.This nano-composite was further characterized by TEM. Obviously,the SBA-15employed has typical p6mm hex-agonal morphology with the well-ordered1D array(Fig.3a). The average pore size of SBA-15is ca.8.0nm,which is very close to the value(ca.7.7nm)determined by N2adsorption. Along[001]orientation,Fig.3b shows that the some pores areﬁlled with Mn3O4nanocrystals.From the pore A to D marked in Fig.3b correspond to the pores from empty to partially and fullyﬁlled;while the features for the SBA-15 nanostructure remains even after forming Mn3O4nanocrys-tals.Nevertheless,further evidences for the location of Mn3O4inside the SBA-15channels are still undergoing in our group.Raman spectra obtained for Mn3O4/SBA-15is presented in Fig.4a.For comparison the Raman spectrum was also recorded for the bulk Mn3O4(97.0%,Aldrich)under the similar conditions(Fig.4b).For the bulk Mn3O4,the bands at310,365, 472and655cmÀ1correspond to the bending modes of Mn3O4, asymmetric stretch of Mn–O–Mn,symmetric stretch of Mn3O4Fig.1.XRD patterns of the bare SBA-15and the Mn3O4/SBA-15nano-composite catalyst.(a)At low angles:(A)Mn3O4/SBA-15,(B)SBA-15;and (b)at high angles of Mn3O4/SBA-15.Fig.2.N2adsorption–desorption isotherms:(!)SBA-15,(~)Mn3O4/SBA-15.Y.-F.Han et al./Applied Catalysis B:Environmental76(2007)227–234229groups,respectively [24–26].However,a downward shift ($D n 7cm À1)of the peaks accompanying with a broadening of the bands was observed for Mn 3O 4/SBA-15.For instance,the distinct feature at 655cm À1for the bulk Mn 3O 4shifted to 648cm À1for the nanocrystals.The Raman bands broadened and shifted were observed for the nanocrystals due to the effect of phonon conﬁnement as suggested previously in the literature [27,28].Furthermore,a weak band at 940cm À1,which should associate with the stretch of terminal Mn O,is an indicative of the existence of the isolated Mn 3O 4group [26].The assignment of this unique band has been discussed in our previous publication [22].3.2.Kinetic study3.2.1.Blank testsUnder a typical reaction conditions,that is,20ml of 100ppm ethanol aqueous solution (pH 6.7)mixed with 1ml of 30%H 2O 2,at 343K,there is no conversion of ethanol was observed after running for 120min in the absence of catalyst or in the presence of bare SBA-15(5mg).Also,under the similar conditions in H 2O 2-free solution,ethanol was not converted for all blank tests even with Mn 3O 4/SBA-15catalyst (5mg)in the reactor.It suggests that a trace amount of oxygen dissolved in water or potential dissociation of adsorbed ethanol does not have any contribution to the conversion of ethanol under reaction conditions.To study the effect of low temperature evaporation of ethanol during reaction,we further examined the concentration of ethanol (100ppm)versus time at different temperatures in the absence of catalyst and H 2O 2.Loss of ca.5%ethanol was observed only at 363K after running for 120min.Hence,to avoid the loss of ethanol through evaporation at high temperatures,which may lead to a higher conversion of ethanol than the real value,the kinetic experiments in this study were performed at or below 343K.The results from blank tests conﬁrm clearly that ethanol can be transformed only by catalytic oxidation during reaction.3.2.2.Effect of amount of catalystThe effect of amount of catalyst on ethanol oxidation is presented in Fig.5.Different amounts of catalyst ranging from 2to 10mg were taken for the same concentration of ethanol (100ppm)in aqueous solution under the standard conditions.It can be observed that the conversion of ethanol increases monotonically within 120min,reaching 15,20and 12%for 2,5and 10mg catalysts,respectively.On the other hand,Fig.5shows that the relative reaction rates (30min)decreased from 0.7to ca 0.1mmol/g Mn min with the rise of catalyst amount from 2to 10mg.Apparently,more catalyst in the system may decrease the rate for ethanol peroxidation,and a proper ratio of catalyst (g)/solution (L)is required for acquiring a balance between the overall conversion of ethanol and reaction rate.In order to investigate the effects from other factors,5mg (catalyst)/20ml (solution),corresponding to 1(g Mn )/30(L)ratio of catalyst/solution,has been selected for the followedexperiments.Fig.4.Raman spectroscopy of the Mn 3O 4/SBA-15(a)and bulk Mn 3O 4(b).Fig.3.TEM images recorded along the [001]of SBA-15(a),Mn 3O 4/SBA-15(b):pore A unﬁlled with hexagonal structure,pores B and C partially ﬁlled and pore D completely ﬁlled.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–2342303.2.3.Effect of temperatureAs shown in Fig.6,the reaction rate increases with increasing the reaction temperature.After 120min,the conversion of ethanol increases from 12.5to 20%when varying the temp-erature from 298to 343K.Further increasing the temperature was not performed in order to avoid the loss of ethanol by evaporation.Interestingly,the relative reaction rate increased with time within initial 60min at 298and 313K,but upward tendency was observed above 333K.3.2.4.Effect of pHIn the pH range from 2.0to 9.0,as illustrated in Fig.7,the reaction rate drops down with the rise of pH.It indicates that acidic environment,or to say,proton concentration ([H +])in the solution is essential for this reaction.With considering our target for this study:purifying water,pH approaching to 7.0in the reaction system is preferred.Because acidifying the solution with organic/inorganic acids may potentially causea second time pollution and result in surplus cost.Actually,there is almost no effect on ethanol conversion with changing pH from 5.5to 6.7in this system.It is really a merit comparing with the conventional homogenous Fenton system,by which the catalyst works only in the pH range of 2.0–5.0.3.2.5.Effect of ethanol concentrationThe investigation of the effect of ethanol concentration on the reaction rate was carried out in the ethanol ranging from 50to 500ppm.The results in Fig.8show that the relative reaction rate increased from 0.07to 2.37mmol/g Mn min after 120min with increasing the concentration of ethanol from 50to 500ppm.It is worth to note that the pH value of the solution slightly decreased from 6.7to 6.5when raising the ethanol concentration from 100to 500ppm.paring to a typical homogenous Fenton reagent For comparison,under the similar reaction conditions ethanol oxidation was performed using aconventionalFig.5.The ethanol oxidation as a function of time with different amount of catalyst.Conversion of ethanol vs.time (solid line)on 2mg (&),5mg (*)and 10mg (~)Mn 3O 4/SBA-15catalyst,the relative reaction rate vs.time (dash line)on 2mg (&),5mg (*)and 10mg (~)Mn 3O 4/SBA-15catalyst.Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,708C and pH of6.7.Fig.6.The ethanol oxidation as a function of temperature.Conversion of ethanol vs.time (solid line)at 258C (&),408C (*),608C (~)and 708C (!),the relative reaction rate vs.time (dash line)at 258C (&),408C (*),608C (~)and 708C (5).Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,pH of 6.7,5mg ofcatalyst.Fig.7.The ethanol oxidation as a function of pH value.Conversion of ethanol vs.time (solid line)at pH value of 2.0(&),3.5(*),4.5(~),5.5(!),6.7(^)and 9.0("),the relative reaction rate vs.time (dash line)at pH value of 2.0(&),3.5(*),4.5(~),5.5(5),6.7(^)and 9.0(").Rest conditions:20ml of ethanol (100ppm),1ml of 30%H 2O 2,708C,5mg ofcatalyst.Fig.8.The ethanol oxidation as a function of ethanol concentration.Conver-sion of ethanol vs.time (solid line)for ethanol concentration (ppm)of 50(&),100(*),300(~),500(!),the relative reaction rate vs.time (dash line)for ethanol concentration (ppm)of 50(&),100(*),300(~),500(5).Condi-tions:20ml of ethanol,pH of 6.7,1ml of 30%H 2O 2,708C,5mg of catalyst.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234231homogenous reagent,Fe 2+(5ppm)–H 2O 2(1ml)at pH of 5.0.It has been reported to be an optimum condition for this system [17].As shown in Fig.9,the reaction in both catalytic systems exhibits a similar behavior,that is,the conversion of ethanol increases with extending the reaction time.Varying reaction temperature from 298to 343K seems not to impact the conversion of ethanol when using the homogenous Fenton reagent.Furthermore,the conversion of ethanol (deﬁning at 120min)in the system of Mn 3O 4/SBA-15–H 2O 2is about 60%of that obtained from the conventional Fenton reagent.There are no other organic compounds observed in the reaction mixture other than ethanol suggesting that ethanol directly decomposing to CO 2and H 2O.3.2.7.Decomposition of H 2O 2In the aqueous solution,the capability of metal ions such as Fe 2+and Mn 2+has long been evidenced to be effective on the decomposition of H 2O 2to produce the hydroxyl radical ( OH),which is oxidant for the complete oxidation/degrading of organic compounds [9,17].Therefore,ethanol oxidation is supposed to be associated with H 2O 2decomposition.The investigation of H 2O 2decomposition has been performed under the reaction conditions (in an ethanol-free solution)with different amounts of catalyst.H 2O 2was introduced into the reaction system by three steps,initially 0.5ml followed by twice 0.25ml at 32and 62min,the pH of 6.7is set for all experiments except pH of 5.0for Fe 2+.As shown in Fig.10,H 2O 2was not converted in the absence of catalyst or presence of bare SBA-15(5mg);in contrast,by using the Mn 3O 4/SBA-15catalyst we observed that ca.Ninety percent of total H 2O 2was decomposed in the whole experiment.It can be concluded that that dissociation of H 2O 2is mainly caused by Mn 3O paratively,the rate of H 2O 2decomposition is relatively low with the homogenous Fenton reagent,total conversion of H 2O 2,was ca.50%after runningfor 120min.Considering the fact that H 2O 2decomposition can be signiﬁcantly enhanced with the rise of Fe 2+concentration,however,it seems not to have the inﬂuence on the reaction rate for ethanol oxidation simultaneously.The similar behavior of H 2O 2decomposition was also observed during ethanol oxidation.The rate for ethanol oxidation is lower for Mn 3O 4/SBA-15comparing to the conventional Fenton reagent.The possible reasons will be discussed in the proceeding section.3.3.Plausible reaction mechanism for ethanol oxidation with H 2O 2In general,the wet peroxide oxidation of organic constitutes has been suggested to proceed via four steps [15]:activation of H 2O 2to produce OH,oxidation of organic compounds withOH,recombination of OH to form O 2and wet oxidation of organic compounds with O 2.It can be further described by Eqs.(1)–(4):H 2O 2À!Catalyst =temperture 2OH(1)OH þorganic compoundsÀ!Temperatureproduct(2)2 OHÀ!Temperature 12O 2þH 2O(3)O 2þorganic compoundsÀ!Temperature =pressureproduct(4)The reactive intermediates produced from step 1(Eq.(1))participate in the oxidation through step 2(Eq.(2)).In fact,several kinds of radical including OH,perhydroxyl radicals ( HO 2)and superoxide anions (O 2À)may be created during reaction.Previous studies [29–33]suggested that the process for producing radicals could be expressed by Eqs.(5)–(7)when H 2O 2was catalytically decomposed by metal ions,such asFeparison of ethanol oxidation in systems of typical homogenous Fenton catalyst (5ppm of Fe 2+,20ml of ethanol (100ppm),1ml of 30%H 2O 2,pH of 5.0acidiﬁed with HCl)at room temperature (~)and 708C (!),and Mn 3O 4/SBA-15catalyst (&)under conditions of 20ml of ethanol (100ppm),pH of 6.7,1ml of 30%H 2O 2,708C,5mg ofcatalyst.Fig.10.An investigation of H 2O 2decomposition under different conditions.One milliliter of 30%H 2O 2was dropped into the 20ml deionized water by three intervals,initial 0.5ml followed by twice 0.25ml at 32and 62min.H 2O 2concentration vs.time:by calculation (&),without catalyst (*),SBA-15(~),5ppm of Fe 2+(!)and Mn 3O 4/SBA-15(^).Rest conditions:5mg of solid catalyst,pH of 7.0(5.0for Fe 2+),708C.Y.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234232and Mn,S þH 2O 2!S þþOH Àþ OH (5)S þþH 2O 2!S þ HO 2þH þ(6)H 2O $H þþO 2À(7)where S and S +represent reduced and oxidized metal ions,both the HO 2and O 2Àare not stable and react further with H 2O 2to form OH through Eqs.(8)and (9):HO 2þH 2O 2! OH þH 2O þO 2(8)O 2ÀþH 2O 2! OH þOH ÀþO 2(9)Presently, OH radical has been suggested to be the main intermediate responsible for oxidation/degradation of organic compounds.Therefore,the rate for ethanol oxidation in the studied system is supposed to be dependent on the concentra-tion of OH.Note that the oxidation may proceed via step four (Eq.(4))in the presence of high pressure O 2,which is so-called ‘‘wet oxidation’’and usually occurs at air pressures (1–22MPa)and at high temperatures (423–643K)[15].However,it is unlikely to happen in the present reaction conditions.According to Wolfenden’s study [34],we envisaged that the complete oxidation of ethanol may proceed through a route like Eq.(10):C 2H 5OH þ OH À!ÀH 2OC 2H 4O À! OHCO 2þH 2O(10)Whereby,it is believed that organic radicals containing hydroxy-groups a and b to carbon radicals centre can eliminate water to form oxidizing species.With the degrading of organic intermediates step by step as the way described in Eq.(10),the ﬁnal products should be CO 2and H 2O.However,no other species but ethanol was detected by GC and GC–MS in the present study possibly due to the rapid of the reaction that leads to unstable intermediate.Fig.5indicates that a proper ratio of catalyst/solution is a necessary factor to attain the high conversion of ethanol.It can be understood that over exposure of H 2O 2to catalyst will increase the rate of H 2O 2decomposition;but on the other hand,more OH radical produced may be scavenged by catalyst with increasing the amount of catalyst and transformed into O 2and H 2O as expressed in Eq.(3),instead of participating the oxidation reaction.In terms of Eq.(10),stoichiometric ethanol/H 2O 2should be 1/6for the complete oxidation of ethanol;however,in the present system the total molar ratio is 1/400.In other words,most intermediates were extinguished through scavenging during reaction.This may explain well that the decrease of reaction rate with the rise of ratio of catalyst/solution in the system.The same reason may also explain the decrease of reaction rate with prolonging the time.Actually,H 2O 2decomposition (ca.90%)may be completed within a few minutes over the Mn 3O 4/SBA-15catalyst as illustrated in Fig.10,irrespective of amount of catalyst (not shown for the sake of brevity);in contrast,the rate for H 2O 2decomposition became dawdling for Fe 2+catalyst.As a result,presumably,the homogenous system has relatively high concentration ofradicals.It may explain the superior reactivity of the conventional Fenton reagent to the presented system as depicted in Fig.9.Therefore,how to reduce scavenging,especially in the heterogeneous Fenton system [29],is crucial for enhancing the reaction rate.C 2H 5OH þ6H 2O 2!2CO 2þ9H 2O(11)On the other hand,as illustrated by Eqs.(1)–(4),all steps in the oxidation process are affected by the reaction temperature.Fig.6demonstrates that increasing temperature remarkably boosts the reactivity of ethanol oxidation in the system of Mn 3O 4/SBA-15–H 2O 2possibly,due to the improvement of the reactions in Eqs.(2)and (4)at elevated temperatures.In terms of Eqs.(6)and (7),acidic conditions may delay the H 2O 2decomposition but enhance the formation of OH (Eqs.(5),(8)and (9)).This ‘‘delay’’is supposed to reduce the chance of the scavenging of radicals and improve the efﬁciency of H 2O 2in the reaction.The protons are believed to have capability for stabilizing H 2O 2,which has been elucidated well previously [18,19].Consequently,it is understandable that the reaction is favored in the strong acidic environment.Fig.7shows a maximum reactivity at pH of 2.0and the lowest at pH of 9.0.As depicted in Fig.8,the reaction rate for ethanol oxidation is proportional to the concentration of ethanol in the range of 50–500ppm.It suggests that at low concentration of ethanol (100ppm)most of the radicals might not take part in the reaction before scavenged by catalyst.With increasing the ethanol concentration,the possibility of the collision between ethanol and radicals can be increased signiﬁcantly.As a result,the rate of scavenging radicals is reduced relatively.Thus,it is reasonable for the faster rate observed at higher concentration of ethanol.Finally,it is noteworthy that as compared to the bulk Mn 3O 4(Aldrich,98.0%of purity),the reactivity of the nano-crystalline Mn 3O 4on SBA-15is increased by factor of 20under the same typical reaction conditions.Obviously,Mn 3O 4nanocrystal is an effective alternative for this catalytic system.The present study has evidenced that the unique structure of SBA-15can act as a special ‘‘nanoreactor’’for synthesizing Mn 3O 4nanocrystals.Interestingly,a latest study has revealed that iron oxide nanoparticles could be immobilized on alumina coated SBA-15,which also showed excellent performance as a Fenton catalyst [35].However,the role of the pore structure of SBA-15in this reaction is still unclear.We do expect that during reaction SBA-15may have additional function to trap larger organic molecules by adsorption.Thus,it may broaden its application in this ﬁeld.So,relevant study on the structure of nano-composites of various MnO x and its role in the Fenton-like reaction for remediation of organic compounds in aqueous solution is undergoing in our group.4.ConclusionsIn the present study,we have addressed a new catalytic system suitable for remediation of trivial organic compound from contaminated water through a Fenton-like reaction withY.-F .Han et al./Applied Catalysis B:Environmental 76(2007)227–234233。