chp5
陕西师范大学_计算机组成原理_课件ppt_白中英第5版_chp5
指令存储器
数据存储器
5.2.3 LAD指令执行过程详解
◊ 取指令过程与MOV指令相同 ◊ 下面讲解执行指令过程
∙43/210∙ 陕西师范大学 计算机科学学院
∙44/210 ∙ , 陕西师范大学 计算机科学学院 ③ ④ ⑤ ⑥ ① 从 指令寄存器中的操作码( CPU 程序计数器 程序计数器内容加 102 识别出是 号地址读出的 PC LAD 中的值为 指令,至此,取指周期即告结束。 1LAD ,变成 102 指令通过指令总线 OP 103 (八进制); )被译码; ,为取下一条指令做好准备; IBUS 装入指令寄存器 IR; ② PC 的内容被放到指令地址总线 ABUS(I) 上,对指存进行译码 并启动读命令;
5.2.2 MOV指令执行过程详解-执行指令 ◊ 执行指令过程详解
∙40/210∙ 陕西师范大学 计算机科学学院
5.6 MOV指令执行过程详解-取指令
10
目标 源
① ③ ⑤ OC 送出控制信号,打开 OC)送出控制信号到通用寄存器,选择 DR ALU 中的数据 输出三态门,将 10 打入到目标寄存器 ALU输出送到数据总线 R1 R0 ( , 10 R0 )作源寄存器,选择 的内容由 DBUS 00 上。注意, 变为10。 R0 ② 操作控制器( ④ OC送出控制信号,将 送出控制信号到 送出控制信号,将 ALU DBUS ,指定 上的数据打入到数据缓冲寄存器 ALU 做传送操作; DR (10 ); ∙41/210∙ 陕西师范大学 计算机科学学院 任何时候 至此, 作目标寄存器; MOV DBUS 指令执行结束。 上只能有一个数据。
∙32/210∙ 陕西师范大学 计算机科学学院
Eg.
合成氨工艺总结
合成氨发展的三个典型特点:1。
生产规模大型化2。
能量的合理利用. 用过程余热自产蒸汽推动蒸汽机供动力,基本不用电能3。
高度自动化Chp2。
原料气的制取2.1 固体燃料气化法氢气的主要来源有:气态烃类转化、固体燃料气化和重质烃类转化。
煤气化技术装置的分类:(1)固定床气化(2)流化床气化(3)气流床气化固定床气化:UGI炉,鲁奇(Lurgi)炉和液态排渣的鲁奇炉流化床气化:Winkler气化炉;Lurgi循环流化床气化炉;U—Gas灰团聚流化床气化炉气流床气化:常压气流床粉煤气化即Koppers-Totzek(柯柏斯—托切克,简称K-T)炉;水煤浆加压气化,即Texaco(德士古)炉和Destec(现E—Gas)炉;粉煤加压气化,即SCGP(Shell 煤气化工艺)。
固定床间歇制气:采用间歇法造气时,空气和蒸汽交替通入煤气发生炉。
通入空气的过程称为吹风,制得的煤气叫空气煤气;通入水蒸气的过程称为制气,制得的煤气叫水煤气;空气煤气与水煤气的混合物称为半水煤气.间歇式制半水煤气流程:a.空气吹风b.上吹制气c.下吹制气d.二次上吹e.空气吹净德士古气化装置包括煤浆制备、气化、灰水处理。
煤浆气化采用德士古水煤浆加压气化的激冷流程。
气化工段关键设备气化炉(参见p56图1-2-39)气化炉分上下两部分,上部为燃烧室,燃烧室内安装三层耐火砖用来防止炉壁烧坏;下部为激冷室.从燃烧室出来的工艺气通过下降管进入激冷室,激冷室上部有激冷环,下部下降管浸入水中,工艺气在水中冷激。
气化炉是德士古装置核心设备。
碳洗塔的作用是洗涤从气化炉来的粗煤气,除去粗煤气中的含杂的灰分以及可容水的反应副产物,保证干净、含灰分少的粗煤气送到下一工段进行使用.碳洗塔下部主要作用是洗涤,碳洗塔合成气入口管线伸入水下,粗煤气进入碳洗塔水下后,经过塔内灰水的洗涤再进入上部;碳洗塔上部有塔盘,采用筛板结构,用来对合成气进行可溶性气体以及灰分进行吸收.碳洗塔是德士古气化装置中,一个非常重要的中间过程装置。
方向控制阀
A B
P T
P T
P T
P T
P T
O型
H型
M型
Y型
P型
Fully close center (O型中位机能)
Fully open center ( H型中位机能)
Tandem center ( M型中位机能)
Float center(Y型中位机能)
阀芯的操作机构 根据控制方式的不同,阀芯操纵机构主要有:
Structure 结构 Fig. 5-4、5 Body 阀体(有油口) Spool 阀芯(阀芯为轴状,上有多个台肩) Actuation 阀芯操作机构
工作原理 阀芯相对阀体移动,改变各油口的连通 方式。 换向阀的“位” “位”(Positions):阀芯相对于阀体可
处
的工作位置个数。
在图形符号中以方框表示,一个方框代
If flow direction reverses:
Pressured oil and the spring push valve core against the seat,flow cannot pass through。 反向流动:液压力及弹簧力方向一致,无法打开 阀口。
一般阀内弹簧较软,开启压力约0.3 ~ 0.5 bar。 若作背压阀用,弹簧设计较硬,开启压力约2 ~ 6 bar,使系统回油保持一定背压。
1DT 2DT 3DT 4DT 5DT 6DT
缸A、B、C均外伸
缸A、B、C均回缩 A外伸,B、C停留
A 伸,B 停,C 缩
Chp.5 Hydraulic Control Valves
液压控制阀
5.1 Introduction 概述
5.2 Directional Control Valves 方向阀 5.3 Pressure Operated Valves 压力阀
定量储层地质学讲稿chp5-1N定量储层勘探地质
当R出1·sinq1<R出2 ·sinq2时,油气往R出2运移。
当R出1·sinq1=R出2 ·sinq2时,油气同时往R出1 和R出2运移。
图5-2 油气运移微观模式图
第一节 储层意义上的油气聚集
二、油气聚集的微观机理
1.油气聚集过程
油
图5-3 油气聚集微观模式图
第一节 储层意义上的油气聚集
二、油气聚集的微观机理
一、单一圈闭中油气分布模型
1.均质储层中的分布模型
油藏顶部
含油饱和度
油藏中部
油藏底部 油藏剖面位置
油 柱 高 度
H
100
含油饱和度So
0
第三节 油气聚集的选优性及非均质性
一、单一圈闭中油气分布模型
2.正韵律储层中的分布模型
各类储层 毛管压力
曲线
油藏剖 面含油 饱和度
油藏顶部
油藏中部
油藏底部 油藏剖面位置
油藏
盖层
夹层阻止油 气往上运移
夹层 夹层形成的小油藏
第三节 油气聚集的选优性及非均质性
二、不同组合圈闭中油气分布模型
2.正韵律排列模型
油藏
油藏 油藏
Ⅲ类差储层
Ⅱ类中等储层
Ⅰ类好储层
油
第三节 油气聚集的选优性及非均质性
二、不同组合圈闭中油气分布模型
2.正韵律排列模型
油藏
油藏 油藏
Ⅲ类差储层
Ⅱ类中等储层
《定量储层地质学》第五章
定量储层勘探地质
第一节 储层意义上的油气聚集
一、油气二次运移的微观机理
– 基本作用力 油气在地下运移的基本作用力为毛管力和浮力及水动力,毛管 力为阻力
– 运移条件 只有当与毛管力方向相反的作用力(浮力、水动力)克服了毛管 力之后,油气才能进入由喉道连接的孔隙系统,这是油气运移的基本理论。
OMCR高级培训教材-chp5-OMC管理
第五章OMCR数据库管理1、informix 目录结构1.1system processor 上的目录结构1.2MMI processor上的目录结构2、数据库的应用软件2.1omc_db_maintomc_db_maint脚本位于OMC_SYS上/$OMC_TOP/current/sbin目录下,是用来对OMC PM数据库中的统计数据进行卸载和删除,并报告数据库的磁盘空间的使用情况。
Omc_db_maint的功能如下:1.如果OMC软件正在运行中,omc_db_maint会将PM parser从PM数据库disconnect.2.Omc_db_maint自动调用db_pm_maint将前一天的统计数据和当前PM 的配置数据从PM数据库卸载备份。
3.压缩从PM数据库卸载下来的数据。
4.自动执行db_pm_maint删除PM上超过delete_flags(一般为5天)以上的统计数据。
5.如果OMC软件正在运行中,omc_db_maint会将EM,LM自动从PM 数据库上disconnect。
6.执行omc_db_ckspace,报告数据库磁盘空间的使用情况。
7.生成一个日志文件,报告omc_db_maint执行的情况。
8.重新连接PM parser和EM,LM应用程序。
2.2onmonitoronmonitor是一个用来对数据库管理的应用软件。
以下是以informix用户身份登入的onmonitor的用户界面:INFORMIX-OnLine: Status Parameters Dbspaces Mode Force-Ckpt ...Status menu to view INFORMIX-OnLine.-----------------------------On-Line------- Press CTRL-W for Help. --------onmonitor应用程序可以友好的菜单的形式来完成informix数据库大部分的管理工作。
chp5地质学历史上的三大(公选)
中最大的弱点。
“水成论”认为地球从形成后,
其形态就没有发生变化过。这和圣
经中对世界起源的解释完全一致,因此得 到了宗教的支持。
魏尔纳的门徒很多,其中最著名的
火山学家布赫和洪宝等。
当魏尔纳到处宣扬水成论时,英国学
者、火成论的创始人——赫顿
(James Hutton 1726-1797)则在苏格兰 从事地质研究工作。
“活动论”认为:
在漫长的地质年代中,大陆与大洋可作 全球规模的位移。 在水平运动力的作用下,被大洋隔开的 大陆可以相互靠近;使其间的大洋消失, 而在原来大陆的位置,可形成新的海洋。
固定论认为:在地壳的演化过程中,垂直于 地表方向的升降运动起着决定性的作用,而水平运 动是派生的,起次要作用的。
居维叶认为: 地球上的生命都遭受过可怕的事件,无 数的生物变成了灾变的牺牲品; 一些陆地上的生物被洪水淹没,另一 些水生生物随海底的突然升起而被爆露在 陆地。因此,这些类群就永世绝灭了。”
居维叶认为: 大灾变后原有的生物绝灭了, 上帝又创造了新的生物类型。
他坚持物种没有渐变,要么 不变,要么灾变。
从小受父亲的影响,对采矿有很大的兴趣。 1769年在弗莱堡矿业学校学习采矿和冶炼技 术,后就读莱比锡,1771年在普兹格大学学习, 1775年任弗莱堡矿业学院教授,一直到退休。 著有《岩石的分类》和《新矿脉成因论》。
魏尔纳 认为岩石是在海洋中化学沉淀
物聚集而成,还认为各岩层间的化石形状各 异,所处位置上下是一定的,因此,可根据 化石种类确定层位。 他认为火山是由地下煤层燃烧而成。 玄武岩不是由火山形成,这是他的论点
为什么在撒哈拉大沙漠中有巨大的冰川遗迹, 而在阿拉斯加会有热带丛林的残痕?
颅底骨折、脑挫裂伤、颅内血肿、颅高压
12
辅助检查
!
1.腰椎穿刺 可以直接测量颅内压力,同时取脑脊液送实验室检查。 但颅内压增高明显时,腰椎穿刺有导致枕骨大孔疝的 危险,应避免进行。
2.影像学检查 电子计算机X线断层扫描(CT)、磁共振成像 (MRI)、数字减影血管造影等检查,有助于诊断病 因和确定病变的部位。
视网膜静脉怒张。 6. 腰椎穿刺测脑脊液为220mmH2O。
目录页
CONTENTS PAGE
Chp1 概念
Chp2 病因和 发病制
Chp3 临床表
现
Chp4 辅助检
查
Chp5 治疗原
则
Chp6 护理诊
断
Chp7 护理措
施
过渡页
TRANSITION PAGE
颅高压
颅内压是指颅腔内容物对颅腔壁所产生的 压力,颅内容物包括脑组织、脑脊液和血 液,三者与颅腔容积相适应,使颅内保持 一定的压力,正常值70~200mmH2O。 当颅腔内容物体积增加或颅腔容积缩小超 过颅腔可代偿的容量,使颅内压持续高于 200mmH2O并出现头痛、呕吐和视神经乳头 水肿三大症状时,称为颅内压增高
34
治疗要点
非手术处理
!
• 原发性脑挫裂伤一般不需要手术治疗。 • 轻型和部分创伤反应较小的中型脑挫裂伤患者,主要是对症治疗、
防治脑水肿,密切观察病情,及时进行颅内压监护及/或复查CT扫描。
手术处理
• 重度脑挫裂伤在颅内压明显增高时应做脑减压术或局部病灶清除术。
颅底骨折、脑挫裂伤、 颅内血肿、颅高压的 护理
第二大组
2
病例分析
第五章系统的稳定性-机械工程控制基础-教案
Chp.5系统稳定性基本要求1.了解系统稳定性的定义、系统稳定的条件;2.掌握Routh判据的必要条件和充要条件,学会应用Routh判据判定系统是否稳定,对于不稳定系统,能够指出系统包含不稳定的特征根的个数;3.掌握Nyquist 判据;4.理解Nyquist 图和Bode 图之间的关系;5.掌握Bode 判据;6.理解系统相对稳定性的概念,会求相位裕度和幅值裕度,并能够在Nyquist 图和Bode 图上加以表示。
重点与难点本章重点1.Routh 判据、Nyquist 判据和Bode 判据的应用;2.系统相对稳定性;相位裕度和幅值裕度求法及其在Nyquist图和Bode 图的表示法。
本章难点Nyquist 判据及其应用。
§1 概念示例:振摆1、稳定性定义:若系统在初始条件影响下,其过渡过程随时间的推移逐渐衰减并趋于0,则系统稳定;反之,系统过渡过程随时间的推移而发散,则系统不稳定。
(图5.1.2)讨论:①线性系统稳定性只取决于系统内部结构和参数,是一种自身恢复能力。
与输入量种类、性质无关。
②系统不稳定必伴有反馈作用。
(图5.1.3)若x0(t)收敛,系统稳定;若x0(t)发散,则系统不稳定。
将X0(s)反馈到输入端,若反馈削弱E(s) →稳定若反馈加强E(s) →不稳定③稳定性是自由振荡下的定义。
即x i(t)=0时,仅存在x i(0-)或x i(0+)在x i(t)作用下的强迫运动而系统是否稳定不属于讨论范围。
2、系统稳定的条件:对[a n p n+a n-1p n-1+…a1p+a0]x0(t)=[b m p m+b m-1p m-1+…b1p+b0]x i(t)令B(s)= a n p n+a n-1p n-1+…a1p+a0 A(s)= b m p m+b m-1p m-1+…b1p+b0初始条件:B0(s) A0(s)则B(s)X0(s)- B0(s)= A(s)X i(s)- B0(s)X i(s)=0,由初始条件引起的输出:L-1变换根据稳定性定义,若系统稳定须满足,即z i为负值。
曼昆_经济学原理答案_英文版chp5
Chapter 5Elasticity and its applicationSolutions to text problemsprice elasticity of demand. Explain the relationship between total QZ Definerevenue and the price elasticity of demand. (page 92)The price elasticity of demand is a measure of how much the quantity demanded of a good responds to a change in the price of that good, calculated as the percentage change in quantity demanded divided by the percentage change in price.The relationship between total revenue and the price elasticity of demand is: (1) when a demand curve is inelastic (a price elasticity less than 1), a price increase raises total revenue, and a price decrease reduces total revenue; (2) when a demand curve is elastic (a price elasticity greater than 1), a price increase reduces total revenue, and a price decrease raises total revenue; and (3) when a demand curve is unit elastic (a price elasticity equal to 1), a change in price does not affect total revenue.price elasticity of supply. Explain why the price elasticity of supply QZ Definemight be different in the long run than in the short run. (page 94)The price elasticity of supply is a measure of how much the quantity supplied of a good responds to a change in the price of that good, calculated as the percentage change in quantity supplied divided by the percentage change in price.The price elasticity of supply might be different in the long run than in the short run because over short periods of time, firms cannot easily change the size of their factories to make more or less of a good. Thus, in the short run, the quantity supplied is not very responsive to the price. However, over longer periods, firms can build new factories or close old ones, or they can enter or exit a market. So, in the long run, the quantity supplied can respond substantially to the price.QZ How might a drought that destroys half of all farm crops be good for farmers? If such a drought is good for farmers, why don’t farmers destroy their own crops in the absence of a drought? (page 100)A drought that destroys half of all farm crops could be good for farmers if the demand for the crops is inelastic. The shift to the left of the supply curve leads to a price increase that raises total revenue because the price elasticity is less than one.Even though a drought could be good for farmers, they wouldn’t destroy their crops in the absence of a drought because no one farmer would have an incentive to destroy her crops, since she takes the market price as given. Only if all farmers destroyed their crops together, for example through a government program, would this plan work to make farmers better off.Questions for review (page 101)1The price elasticity of demand measures how much the quantity demanded responds to a change in price. The income elasticity of demand measures how much the quantity demanded changes as consumer income changes.2The determinants of the price elasticity of demand include whether the good is a necessity or a luxury, how available close substitutes are, how broadly defined the market is, and the time horizon.Luxury goods have greater price elasticity than necessities, goods with close substitutes have greater elasticity, goods in more narrowly defined markets have greater elasticity, and goods have greater elasticity the longer the time horizon.3Elasticity greater than 1 means demand is elastic. When the elasticity is greater than 1, the percentage change in quantity demanded exceeds the percentage change in price. When the elasticity60 Principles of Economics, Third edition, Instructor’s Manualequals 0, demand is perfectly inelastic. There is no change in quantity demanded when there is a change in price.4Figure 5.1 presents a supply-and-demand diagram, showing equilibrium price, equilibrium quantity, total spending by consumers and the total revenue received by producers. Total spending byconsumers equals the equilibrium price times the equilibrium quantity. Total revenue received by producers also equals the equilibrium price times the equilibrium quantity. These are shown by the area of the rectangle in Figure 5.1.Figure 5.15If demand is elastic, an increase in price reduces total revenue. With elastic demand, the quantity demanded falls by a greater percentage than the percentage increase in price. As a result, total revenue declines.6 A good with an income elasticity less than 0 is called an inferior good because as income rises, thequantity demanded declines.Chapter 5: Elasticity and its application 61 7The price elasticity of supply is calculated as the percentage change in quantity supplied divided by percentage change in price.Price elasticity of supply =% change in quantity supplied % change in priceIt measures how much the quantity supplied responds to changes in the price.8The price elasticity of supply of Picasso paintings is zero, since no matter how high price rises, no more can ever be produced.9The price elasticity of supply is usually larger in the long run than it is in the short run. Over short periods of time, firms cannot easily change the size of their factories to make more or less of a good, so the quantity supplied is not very responsive to price. Over longer periods, firms can build new factories or close old ones, so the quantity supplied is more responsive to price.10OPEC was unable to maintain a high price through the 1980s because the elasticity of supply and demand were more elastic in the long run. When the price of oil rose, producers of oil outside of OPEC increased oil exploration and built new extraction capacity. Consumers responded withgreater conservation efforts. As a result, supply increased and demand fell, leading to a lower price for oil in the long run.Problems and applications (page 102)1 a Mystery novels have more elastic demand than required textbooks, because mystery novels haveclose substitutes and are more of a luxury good, while required textbooks are more of a necessity with no close substitutes. If the price of mystery novels were to rise, readers could substituteother types of novels, or buy fewer novels altogether. But if the price of required textbooks were to rise, students would have little choice but to pay the higher price. Thus the quantity demanded of required textbooks is less responsive to price than the quantity demanded of mystery novels.b Beethoven recordings have more elastic demand than classical music recordings in general.Beethoven recordings are a narrower market than classical music recordings, so it is easy to find close substitutes for them. If the price of Beethoven recordings were to rise, people couldsubstitute other classical recordings, like Mozart. But if the price of all classical recordings were to rise, substitution would be more difficult. A transition from classical music to hip-hop, forexample, is less likely. Thus the quantity demanded of classical recordings is less responsive to price than the quantity demanded of Beethoven recordings.c Heating oil during the next 5 years has more elastic demand than heating oil during the next 6months. Goods have a more elastic demand over longer time horizons. If the price of heating oil were to rise temporarily, consumers couldn’t switch to other sources of fuel without greatexpense. But if the price of heating oil were to be high for a long time, people would gradually switch to gas or electric heat. As a result, the quantity demanded of heating oil during the next 6 months is less responsive to price than the quantity demanded of heating oil during the next 5years.d Lemonade has more elastic demand than water. Lemonade is a luxury with close substitutes,while water is a necessity with no close substitutes. If the price of water were to rise, consumers have little choice but to pay the higher price. But if the price of lemonade were to rise,consumers could easily switch to other soft drinks. So the quantity demanded of lemonade ismore responsive to price than the quantity demanded of water.2 a(i) For business travellers, the price elasticity of demand when the price of tickets risesfrom $200 to $250 is [(2,000 – 1,900)/1,950]/[(250 – 200)/225] = 3/13 = 0.23.(ii) For holiday-makers, the price elasticity of demand when the price of tickets risesfrom $200 to $250 is [(800 – 600)/700] / [(250 – 200)/225] = 9/7 = 1.29.b The price elasticity of demand for holiday-makers is higher than the elasticity for businesstravellers because holiday-makers can more easily choose a different mode of transportation like driving or taking the train. Business travellers are less likely to do so since time is moreimportant to them and their schedules are less adaptable.62 Principles of Economics, Third edition, Instructor’s Manual3 a(i) If your income is $10,000, your price elasticity of demand as the price of compactdiscs rises from $8 to $10 is [(40 – 32)/36] / [(10 – 8)/9] = 1(ii) If your income is $12,000, the elasticity is [(50 – 45)/47.5] / [(10 – 8)/9] = 9/19 =0.47b(i) If the price is $12, your income elasticity of demand as your income increases from $10,000 to $12,000 is [(30 – 24)/27] / [(12,000 – 10,000)/11,000] = 11/9 = 1.22.(ii) If the price is $16, your income elasticity of demand as your income increases from $10,000 to $12,000 is [(12 – 8)/10] / [(12,000 – 10,000)/11,000] = 11/5 = 2.2.4 a If Emily always spends one-third of her income on clothing, then her income elasticityof demand is one, since maintaining her clothing expenditures as a constant fraction ofher income means the percentage change in her quantity of clothing must equal herpercentage change in income. For example, suppose the price of clothing is $30, herincome is $9,000, and she purchases 100 clothing items. If her income rose 10 percentto $9,900, she’d spend a total of $3,300 on clothing, which is 110 clothing items, a 10percent increase.b Emily’s price elasticity of clothing demand is also one, since every percentage point increase inthe price of clothing would lead her to reduce her quantity purchased by the same percentage.Again, suppose the price of clothing is $30, her income is $9,000, and she purchases 100clothing items. If the price of clothing rose 1 percent to $30.30, she would purchase 99 clothing items, a 1 percent reduction. Note this part of the problem can be confusing to students if theyhave an example with a larger percentage change and they use the point elasticity calculationmethod. This example can be used to further illustrate the usefulness of the midpoint method for any size change.c Since Emily spends a smaller proportion of her income on clothing, then for any given price, herquantity demanded will be lower. Thus her demand curve has shifted to the left. But becauseshe’ll again spend a constant fraction of her income on clothing, her income and price elasticities of demand remain one.5 a With a 4.3 percent decline in quantity following a 20 percent increase in price, theprice elasticity of demand is only 4.3/20 = 0.215, which is fairly inelastic.b With inelastic demand, the revenue rises when the fare rises.c The elasticity estimate might be unreliable because it’s only the first month after the fareincrease. As time goes by, people may switch to other means of transportation in response to the price increase. So the elasticity may be larger in the long run than it is in the short run.6Tom’s price elasticity of demand is zero, since he wants the same quantity regardless of the price.Jerry’s price elasticity of demand is one, since he spends the same amount on gas, no matter what the price, which means his percentage change in quantity is equal to the percentage change in price.7To explain the observation that spending on restaurant meals declines more during economic downturns than does spending on food to be eaten at home, economists look at the income elasticity of demand. In economic downturns, people have lower income. To explain the observation, the income elasticity of restaurant meals must be larger than the income elasticity of spending on food to be eaten at home.8 a With a price elasticity of demand of 0.4, reducing the quantity demanded of cigarettes by 20percent requires a 50 percent increase in price, since 20/50 = 0.4. With the price of a pack ofcigarettes currently at $8, this would require an increase in the price to $13.33 a pack using the midpoint method (note that ($13.33 – $8)/$10.67 = 0.50).b The policy will have a larger effect five years from now than it does one year from now. Theelasticity is larger in the long run, since it may take some time for people to reduce theircigarette usage. The habit of smoking is hard to break in the short run.c Since teenagers don’t have as much income as adults, they are likely to have a higher priceelasticity of demand.9You’d expect the price elasticity of demand to be higher in the market for vanilla ice cream than for all ice cream because vanilla ice cream is a narrower category and other flavours of ice cream are almost perfect substitutes for vanilla.Chapter 5: Elasticity and its application 63 You’d expect the price elasticity of supply to be larger for vanilla ice cream than for all ice cream. A producer of vanilla ice cream could easily adjust the quantity of vanilla ice cream and produce other types of ice cream. But a producer of ice cream would have a more difficult time adjusting the overall quantity of ice cream they produced.10 a As Figure 5.2 shows, in both markets, the increase in supply reduces the equilibrium price andincreases the equilibrium quantity.b In the market for pharmaceutical drugs, with inelastic demand, the increase in supply leads to arelatively large decline in the price and not much of an increase in quantity. This marketexperiences a larger change in price.Figure 5.2c In the market for computers, with elastic demand, the increase in supply leads to a relativelylarge increase in quantity and not much of a decline in price. This market experiences a largerchange in quantity.d In the market for pharmaceutical drugs, since demand is inelastic, the percentage increase inquantity will be less than the percentage decrease in price, so total consumer spending willdecline. In contrast, since demand is elastic in the market for computers, the percentage increase in quantity will be greater than the percentage decrease in price, so total consumer spending will increase.11 a As Figure 5.3 shows, in both markets, the increase in demand increases both the equilibriumprice and the equilibrium quantity.b In the market for beachfront resorts, with inelastic supply, the increase in demand leads to arelatively large increase in the price and not much of an increase in quantity. This marketexperiences a larger change in price.c In the market for cars, with elastic supply, the increase in demand leads to a relatively largeincrease in quantity and not much of an increase in price. This market experiences a largerchange in quantity.d In both markets, total consumer spending rises, since both equilibrium price and equilibriumquantity rise.64 Principles of Economics, Third edition, Instructor’s Manual Figure 5.3Quantity of cars 12 a Vineyard owners whose vines weren’t destroyed benefited because the destruction of some ofthe vines reduced the supply, causing the equilibrium price to rise.b To tell whether vineyard owners as a group were hurt or helped by the floods, you’d need toknow the price elasticity of demand. It could be that the additional income earned by vineyard owners whose vines weren’t destroyed rose more because of the higher prices than the lossesmade by vineyard owners whose vines were destroyed, if demand is inelastic.13 A worldwide drought could increase the total revenue of farmers if the price elasticity of demand forgrain is inelastic. The drought reduces the supply of grain, but if demand is inelastic, the reduction of supply causes a large increase in price. Total farm revenue would rise as a result. If there’s only a drought in Queensland, Queensland’s production isn’t a large enough proportion of the total farm product to have much impact on the price. As a result, price is basically unchanged, while the output of Queensland farmers declines, thus reducing their income.14 When productivity increases for all farmland at a point in time, the increased productivity leads to arise in farmland prices, since more output can be produced on a given amount of land. But prior to the technological improvements, the productivity of farmland depended mainly on the prevailing weather conditions. There was little opportunity to substitute land with worse weather conditions for land with better weather conditions. As technology improved over time, it became much easier to substitute one type of land for another. So the price elasticity of supply for farmland increased over time, since now land with bad weather is a better substitute for land with good weather. Theincreased supply of land reduced farmland prices. As a result, productivity and farmland prices are negatively related over time.15 Not necessarily. If demand for luxury cars is price elastic, then raising the price of luxury cars byincreasing the tax will decrease the total revenue from luxury cars. It is likely that demand for luxury cars is elastic as they are more of a luxury than a necessity. P r i c e o f c a r s。
大地电磁学_chp5野外工作方法及资料处理
5.1.2 野外资料采集
测点的选择地方的环境对观测质量的关系很大,为 了获得高质量的野外观测资料,测点选择的原则是:
1. 根据地质任务及施工设计书,布臵测线、测点,在施工 中允许根据实际情况在一定范围内调整,但必须满足规 范要求。若测区内有有利异常,应及时申请加密测线测 点,以保证至少应有三个测点位于异常部位。 2. 测点附近地形应当平坦,尽量不要选在狭窄的山顶或深 沟底部,应选在开阔的平地布极,至少两对电极的范围 内地面相对高差与电极之比小于10%,以避免地形的起 伏影响大地电流场的分布。
大地电磁学 Geo-electromagnetism Magnetotellurics(MT)
地球物理专业用
成都理工大学
Mao Lifeng 2011年3月20日
第五章 野外工作方法与资料处理解释
• 5.1 野外工作方法
–5.1.1 –5.1.2 –5.1.3 –5.1.4 施工设计 野外资料采集 常见的干扰信号 提高资料观测质量的措施
* * * E y , H x H x , H x Z yx H y , H x Z yy
E y , H * H x , H * Z yx H y , H * Z yy y y y
S2-5-Chp5-JSP应用优化
JNDI1.1 JNDI的全称是Java命名与目录接口(Java Naming and Directory Interface),是一个应用程序设计的API,为开发人员提供了查找和访问各种命名和目录服务的通用,统一的接口。
1.2 我们可以把JNDI简单地理解为是一种将对象和名字绑定的技术,即指定一个资源名称,将该名称与某一资源或服务相关联。
1.3 conf目录下的context.xml文件是全局的上下文配置文件,对所有的Web应用有效。
1.4 练习:在Tomcat中发布一条信息供所有的Web应用程序使用示例1context.xml的代码如下所示<Context><Environment name=”tjndi” value=”hello JNDI” type=”ng.String” /> </Context>示例2:<%@ page import=”javax.naming.*”%><%//javax.naming.Context提供了查找JNDI Resource的接口Context ctx = new InitialContext();//java:comp/env/为前缀String testjndi = (String)ctx.lookup(“java:comp/env/tjndi”);%>1.5 Environment元素常用的属性如下? name:相对与java:comp/env的名称? type:Java类名? value:返回给应用的参数值application对象只能在一个Web应用程序中使用,而使用JNDI发布的信息是对服务器上所有的Web应用程序都可见。
数据库连接池1.1. 数据库连接池负责分配,管理和释放数据库连接,它允许应用程序重复使用一个现有的数据库连接,而不是重新建立一个;释放空闲时间超过最大空闲时间的数据库连接,以避免因为没有释放数据库连接而引起的数据库连接遗漏。
创业管理(张秀娥)chp5第五章 商业模式开发
6
阿里巴巴
目前,阿里巴巴堪称世界B2B商业模式的典范。她 的B to B模式是如何开发,又是如何被有效运行 并最终得以实现卓越盈利的呢? 。 1988年马云以5万元开始创业。当时中国的基本 宏观经济形势是,中国和发达国家同样面对信 息技术带来的巨大商机和挑战,而在中国加入 世贸组织之后,将迎来“中国会成为世界工 厂!”的社会现实。马云也许预测到了这些宏 观经济形势,并敏锐地识别出这些对于中国电 子商务发展路径的深刻意义。他绕开收费入网 模式,毅然推出了企业免费入网的概念。
要素 1.客户选择 2.价值获取 3.战略控制
4.业务范围
表5-2 设计商业模式应考虑的内容
要解决的问题
具体内容
企业希望对哪些客户提供服务? 企业能够为哪些客户提供价值?如何选 择客户?
企业将如何盈利?
如何为客户创造价值?我的盈利模式是 什么?
企业将如何保护利润流?
我的客户选择我公司产品的理由是什么? 公司的价值判断与对手相比有什么 特点?
16.10.2020
a
13
因而,商业模式是一个企业从研发、制造、销 售,直至售后服务的具体的,并区别于其他企 业的可盈利的流程结构。
16.10.2020
a
14
二、商业模式的功能
第一,发现渴望得到需求满足的客户群;
第二,建立与上游企业的合作,以合适的成本 生产出定价符合市场供求的产品和服务;
a
16
第二节 商业模式的构成要素及类型
一、商业模式的构成要素 有效商业模式的四大关键要素:
核心战略(企业如何竞争) 战略资源(企业如何获得和使用拥有的资源) 伙伴网络(企业如何构建和培育合作伙伴关系) 顾客界面(企业如何与顾客互动)
数学物理方法chp5-3 傅里叶变换delta函数
a
11
5.函数的
( x ) 0 的实根 xk (k 1,2,3,) 全为单根 ( ' ( x) 0) 有 ( x xk ) ( x ) k | ' ( xk ) |
0, ( x ) 0 ( x) , ( x ) 0
1/l -l/2
o
l/2
x
15
(2)sinc 函数序列:
1 sin Kx ( x ) lim K x
6 5 4 3
K=8
K=16
sinKt/(pi*t)
2 1 0 -1 -2 -2
K=4Leabharlann -1.5-1-0.5
0 t
0.5
1
1.5
2
16
(3) 函数序列: ( x )
60
lim
m x 0, ( x 0) ( x) lim l ( x) lim rect , ( x 0) l 0 l 0 l l
( x)dx lim l ( x)dx m
l 0
引入δ函数:
0, ( x 0) ( x) , ( x 0) 0, a ( x)dx 1
(一)δ函数概念
– 问题 • 质点的密度函数如何表示? • 一般函数无法描写物理上的“点源”,如“点电荷”、 “质点”的密度,以及“瞬时力”等概念。 – 思路 • 质点是物体在尺度趋于零时的理想模型; • 一个位于原点、长度l、质量为m的线,线密度为 l(x)=m/l rect(x/l)的物体,当l->0时,可以看成质点;
( x ) C ( )eix d
网络设备安装与调试chp5CDP电子教案
CDP协议教学目标1、掌握cdp的工作原理2、掌握cdp的应用重点难点1、 Cdp特征2、 Cdp邻居表的查看应知1、 Cdp是链路层的协议,不依赖网络来工作,是cisco的私有协议2、 Cdp是通过周期性发送cdp包来完成工作的3、 Cdp仅能看到直接的设备应会1、 Cdp邻居表的查看2、通过cdp表画出网络的拓扑3、关闭和开启接口下的cdp4、关闭和开启整个路由器的cdp5、调整cdp的运行参数教学方法1、宏观上采用“实例驱动”,在微观上采用“边看边学”,学生通过教师的演示学习CDP的基本配置方法。
2、在课堂上注意讲、学、做相结合,注重与学生的互动,充分调动学生的积极性,培养学习兴趣、分析问题和解决问题的能力以及自学能力。
3、课堂上引入专业词汇,要求学生掌握。
教学过程1、回顾OSI七层中的数据层和网络层2、问题引入:为什么需要cdp?3、课程过程(1) Cdp的工作原理•私有协议•直连设备•周期性发送cdp包,收到相邻设备的cdp包后,保存cdp包并倒计时(2) Cdp的使用和配置•Show cdp neighbor命令•通过cdp表复原出网络拓扑•接口下和全局下cdp的关闭和开启•Cdp参数的调整•Cdp工作过程的监控(debug命令)4、小结•介绍了cdp的工作原理•介绍了cdp的配置5、专业英语•CDP:CISCO设备发现协议6、课后作业•提交实验报告•Cisco设备特有的、用来查找相邻设备的协议是,该协议是OSI 第层协议。
•关闭整路由器的CDP使用命令。
•关闭路由器某个接口的CDP使用命令。
Chp5_工业车辆(全)
5.2.1 叉车_组成与分类
(1)前移式叉车特点:门架(或货叉)可
以前后移动,运行时货物 重心位于前、后轮之间, 运行稳定,不需要平衡重, 自重轻,降低通道宽度要 求。 适用条件:车间、仓库内 通道较小。
5.2.1 叉车_组成与分类
(2)插腿式叉车
特点:体积小、重量轻、 灵活方便,比前移式叉 车和立体仓库堆垛机投 资少的多。 适用条件:仓库、车间、 集装箱 等地面平坦的场 所
5.1.1手动简易设备-手动液压升降平台车
适用范围 手动液压升降平台车 是采用手压或脚踏为动 力,通过液压驱动使载 重平台作升降运动的手 推平台车。可调整货物 作业时的高度差,减轻 操作人员的劳动强度。
5.1.1手动简易设备-手推液压堆高车
类别定义:手推液压堆高车 是利用人力推拉运行的简易 式查腿式叉车。其起升机构 有:手摇机械式(左图)、 手动液压式(右上图)和电 动液压式(右下图)三种, 适用于工厂车间、仓库内效 率要求不高,但需要有一定 堆垛、装卸高度的场合。 性能参数 载 重 量 500——1000kg 起升高度 1000——3000 mm 货叉最低离地高度≤100 mm
三点支撑式比四点支撑式转弯半径小。
5.2.2 叉车_参数
自重:叉车整备质量,包括燃油或电池 等(1~10吨)。 自重利用系数:
最大起重量 整备质量 最 大 起 重 量× 载 荷 中 心 距 离 整备质量
或
5.2.2 叉车_参数
其他参数: 外形尺寸、轴距、轮压等。
(参数举例见教材106页)
5.2.2 叉车_参数
起升速度:正常条件下,货叉上升的平均 速度(一般15~20m/min)。 最大运行速度:叉车满载时,在坚实、平 坦、干燥地面行驶的最大速度(一般电动叉 车13km/h,内燃机叉车20km/h)。
Zigbee技术
34 Chap6 协议结构
1.查找网络协调器。首先会主动扫描查找周围网络的协调器,如果在扫描期 限内检测到信标,那么将获得了协调器的有关信息,这时就向协调器发出连 接请求。在选择合适的网络之后,上层将请求mac层对物理层和mac层的 phyCurrentChannel、macPANID等PIB属性进行相应的设置。如果没有检测到, 间隔一段时间后,节点重新发起扫描。 2.发送关联请求命令(Associate request command)。节点将关联请求命令 发送给协调器,协调器收到后立即回复一个确认帧(ACK),同时向它的上 层发送连接指示原语,表示已经收到节点的连接请求。但是这并不意味着已 经建立连接,只表示协调器已经收到节点的连接请求。当协调器的mac层的 上层接收到连接指示原语后,将根据自己的资源情况(存储空间和能量)决 定是否同意此节点的加入请求,然后给节点的mac层发送响应。
10 Chap3 技术特点
2. 低成本
由于ZigBee模块的复杂度不高,ZigBee协议免专利费,再加之使用的 频段无需付费,所以它的成本较低。
市面上的zigbee学习开发板大概是500-700人民币三个模块,其中 有带功放的,传输距离远一点,如果需要LCD显示器的话可能会贵一点, 价格会在两千左右(三四个节点),但这是开发板,如果自 己焊制、生产一个Zigbee节点其成本远远低于以上的价格,批量生产 的话应该可以控制在50元人民币左右成都无限龙公司和蜂舞Zigbee公 司是市场上的主力军,除了提供开发套件,还承接Zigbee项目。
MAC协议包括以下功能:
设备间无线链路的建立、维护和结束; 确认模式的帧传送与接收;
LLC子层的主要功能包括: 传输可靠性保障和控制;
信道接入控制; 帧校验; 预留时隙管理;
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6 列举我们学过的信源编码:香农编码、费诺编码、 算术编码、LZ 编码。 7.以下编码结果码 1、码 2、码 3、码 4 分别是 ( 信源符号 xi 符号出现概率 x1 x2 x3 x4 1/2 1/4 1/8 1/8 码1 0 11 00 11 码2 0 10 00 01 码3 1 10 100 1000
第 5 章测验 1. 若一离散无记忆信源的信源熵 H(X)等于 2.5,对信源进行定长的无失真二 进制编码,则编码长度至少为__________________。 2. 对于香农编码、费诺编码和哈夫曼编码,编码方法惟一的是_________。 3. 根据香农第一编码定理,当找到唯一可译码后,则信源 S 中每个信源符号所 需的平均码长满足的条件为 _______________________。 4. _____码是一种高效的通用编码,现在已经成为计算机文件压缩的标准算法, 常用的 ZIP、ARC 压缩解压程序都是对它的改进。 5.对具有 8 个消息的单符号离散无记忆信源进行 4 进制哈夫曼编码时, 为使平均 码长最短,应增加____________个概率为 0 的消息。 A) 1 B) 2 C) 3 、 D7 s8 S s1 5 设有信源 对该信源 , P( S ) 0.4 0.22 0.1 0.08 0.05 0.05 0.05 0.05
编二进制哈夫曼码,并求信源的熵、平均码长以及编码效率。
) 码4 1 01 001 0001
A、分组码、非奇异码、即时码、唯一可译码 B、非奇异码、分组码、唯一可译码、即时码 C、非奇异码、奇异码、即时码、唯一可译码 D、奇异码、非奇异码、唯一可译码、即时码
第 5 章作业: 1 简述香农第一定理的内容及意义。 2 习题 5.4
3 已知信源的各个符号分别为字母 A,B,C,D,现用二进制码元对符号字母作 信源编码,A x0y0,B x0y1,C x1y0,D x1y1,每个二进制码元的长度为 5ms 。 若 各 个 字 母 的 出 现 概 率 分 别 为 P(A)=1/5, P(B)=1/4, P(C)=1/4, P(D)=3/10,计算在无噪离散信道上的平均信息传输速率。 4 设有一单符号离散信源,P(X)=(0.32,0.22,0.18,0.16,0.08,0.04) , 对该信源进行二进制香农编码及费诺编码,并求编码效率。