作业题答案
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高空作业考试题及答案高空作业安全知识考试题一、单选题(每题2分,共20分)1. 高空作业的定义是什么?A. 在地面上进行的作业B. 在离地面2米以上的作业C. 在室内进行的作业D. 在室外进行的作业2. 进行高空作业时,以下哪个措施是不必要的?A. 佩戴安全帽B. 系安全带C. 穿高跟鞋D. 使用安全网3. 高空作业人员在作业前需要进行哪些检查?A. 检查作业工具是否齐全B. 检查作业环境是否安全C. 检查个人身体状况D. 所有以上选项4. 高空作业时,以下哪种行为是正确的?A. 酒后作业B. 疲劳作业C. 遵守作业规程D. 擅自改变作业方案5. 高空作业中,当遇到紧急情况时,以下哪种做法是正确的?A. 立即停止作业,撤离到安全区域B. 继续作业,完成工作C. 等待上级指示D. 尝试自行解决问题二、判断题(每题1分,共10分)6. 高空作业时,可以不佩戴安全带。
()7. 高空作业人员应定期进行身体检查。
()8. 高空作业时,可以使用不稳定的支撑物。
()9. 高空作业人员在作业过程中可以吸烟。
()10. 高空作业人员在作业前应接受安全教育和培训。
()三、简答题(每题5分,共30分)11. 请简述高空作业的“三不伤害”原则是什么?12. 高空作业中,如何正确使用安全带?13. 描述一下高空作业中常见的危险因素有哪些?14. 高空作业人员在作业过程中应注意哪些安全事项?四、案例分析题(每题10分,共40分)15. 某建筑工地发生一起高空坠落事故,一名工人在没有系安全带的情况下进行高空作业,不慎从高处坠落,造成重伤。
请分析事故发生的原因及预防措施。
16. 描述一个高空作业现场的安全检查流程。
17. 高空作业人员在作业过程中突然感到身体不适,他应该如何正确处理?18. 假设你是一名高空作业安全监督员,你将如何制定一个高空作业安全管理制度?答案:一、单选题1. B2. C3. D4. C5. A二、判断题6. ×7. √8. ×9. × 10. √三、简答题11. 高空作业的“三不伤害”原则是:不伤害自己,不伤害他人,不被他人伤害。
精细有机合成-课后作业题参考答案第2章作业题1、将下列化合物写出结构,按其进行硝化反应的难易次序加以排列:苯、乙酰苯胺、苯乙酮、甲苯、氯苯2、在下列取代反应中,主要生成何种产物?3、什么是溶剂化作用?溶剂化作用指的是每一个被溶解的分子或离子被一层或几层溶剂分子或松或紧地包围的现象。
溶剂化作用是一种十分复杂的现象,它包括溶剂与溶质之间所有专一性和非专一性相互作用的总和。
4、相转移催化主要用于哪类反应?最常用的相转移催化剂是哪类化合物?主要用于液-液非均相亲核取代反应。
最常用的相转移催化剂是季铵盐Q+X-。
第3章作业题1、什么是卤化反应? 引人卤原子有哪些方式?向有机化合物分子中的碳原子上引入卤原子的反应。
引人卤原子的方式有加成卤化、取代卤化、置换卤化。
2、除了氯气以外,还有哪些其他氯化剂?卤化氢+氧化剂、卤化氢或盐、其它。
3、在用溴素进行溴化时,如何充分利用溴?加入强氧化剂次氯酸钠和双氧水等。
4、用碘和氯气进行芳环上的取代碘化时,氯气用量不易控制,是否有简便的碘化方法?(1)I2+H2O2作碘化剂的优点是成本低,操作简便。
缺点是不适用于原料和产物易被H2O2氧化的情况。
(2)I2+Cl2作碘化剂的优点是可用于原料和产物易被H2O2氧化的情况。
缺点是在水介质中使用时会生成具有氧化性的HClO,另外氯气的用量不易控制。
(3)用ICl作碘化剂的优点是碘化时不产生HI,不需要另加氧化剂,可在水介质中用于原料和产物易被氧化的情况。
缺点是ICl是由I2和Cl2反应制得的,易分解,要在使用时临时配制。
5、请写出芳环上取代卤化的反应历程。
6、芳环上亲电取代卤化时,有哪些影响因素?被卤化物的结构、卤化剂、催化剂、卤化深度、卤化介质的PH值、卤化溶剂、卤化温度、被卤化物中和卤化剂中的杂质等。
7、完成下列反应式8、写出从甲苯制备以下化合物的合成路线。
(1)间氯三氟甲苯(2)3,4-二氯三氟甲苯(3)2,4-二氯三氟甲苯(4)2-氯-5-溴三氟甲苯第4章作业题1、采用三氧化硫为磺化剂有哪些优缺点?用三氧化硫磺化,其用量接近理论量,磺化剂利用率高,成本低。
作业考试题库及答案一、单项选择题(每题2分,共20分)1. 以下哪项不是计算机病毒的特征?A. 破坏性B. 传染性C. 潜伏性D. 可预测性答案:D2. 在Excel中,以下哪个函数用于计算一组数值的平均值?A. SUMB. AVERAGEC. MAXD. MIN答案:B3. 以下哪个选项是HTML文档的根元素?A. <html>B. <head>C. <body>D. <title>答案:A4. 在Word文档中,以下哪个快捷键用于插入当前日期?A. Ctrl + DB. Ctrl + Shift + ;C. Ctrl + Alt + DD. Ctrl + Shift + D答案:B5. 在PowerPoint中,以下哪个视图模式用于编辑幻灯片的详细内容?A. 普通视图B. 幻灯片浏览视图C. 幻灯片放映视图D. 大纲视图答案:A6. 在Photoshop中,以下哪个工具用于选择图像中的特定区域?A. 画笔工具B. 套索工具C. 橡皮擦工具D. 钢笔工具答案:B7. 在JavaScript中,以下哪个关键字用于声明一个函数?B. letC. functionD. const答案:C8. 在数据库中,以下哪个操作用于删除表中的记录?A. DELETEB. DROPC. INSERTD. UPDATE答案:A9. 在Unix/Linux系统中,以下哪个命令用于查看当前目录下的文件和文件夹?A. lsB. pwdD. mkdir答案:A10. 在计算机网络中,以下哪个协议用于域名解析?A. FTPB. HTTPC. DNSD. SMTP答案:C二、多项选择题(每题3分,共15分)11. 以下哪些是计算机硬件的组成部分?A. 中央处理器(CPU)B. 随机存取存储器(RAM)C. 操作系统(OS)D. 硬盘驱动器(HDD)答案:A, B, D12. 在Excel中,以下哪些函数用于统计分析?A. COUNTB. COUNTIFC. SUMIFD. AVERAGEIF答案:A, B, C, D13. 在HTML中,以下哪些标签用于布局?A. <div>B. <span>C. <table>D. <ul>答案:A, C14. 在Word中,以下哪些功能用于格式化文档?A. 字体加粗B. 段落对齐C. 插入表格D. 插入图片答案:A, B, C, D15. 在PowerPoint中,以下哪些视图模式用于演示文稿的布局和设计?A. 普通视图B. 幻灯片浏览视图C. 幻灯片放映视图D. 大纲视图答案:A, B, D三、判断题(每题1分,共10分)16. 计算机病毒只能通过电子邮件传播。
江苏省危险化学品企业特殊作业习题姓名单位名称身份证号一、单项选择题(30题)1、下列作业中不需要办理动火作业许可证的是(A)A.化验室中的电炉加热作业B.乙炔气柜附近使用砂轮作业C.氨合成装置区内进行气割作业D.汽油罐区进行焊接作业2、特殊作业前,应对参加作业的人员进行安全教育,下列不属于安全教育内容的是(C)A.事故的预防、避险、逃生、自救及互救知识B.作业过程中所使用的个体防护器具的使用方法和注意事项C.风险分析的主要方法D.作业现场和作业过程中可能存在的危害因素及应采取的具体安全措施3、在500m3的甲醇储罐内中上部位进行动火作业,应对(D)进行监测分析。
A.上部B.中部C.下部D.以上所有部位均应分析4、当被测气体或蒸气的爆炸下限小于4%时,动火分析的合格标准是:其被测浓度(体积百分数)不应大于(B)A.0.5%B.0.2%C.2%D.5%5、当被测气体或蒸气的爆炸下限大于4%时,动火分析的合格标准是:其被测浓度(体积百分数)不应大于(A)A.0.5%B.0.2%C.2%D.5%6、某地5月的一天,风力六级,该地一企业丙酮精馏装置区域内冷凝器循环冷却水管线破裂,需要动火检修,以下说法正确的是(B)A.有监护人在就可以动火B.可以动火,但应升级管理C.只要车间主任签字即可动D.环境分析合格即可动火7、下列选项不是动火安全作业许可证的必要内容的是(D)A.动火分析的具体数值B.动火的起止时间C.危害辨识和安全措施D.环境温度8、下列选项中叙述错误的是(D)A.动火作业前,应清理动火现场及周围的可燃物质。
B.动火作业前,应办理动火作业证,按要求进行动火分析。
C.动火作业前,应采取有效的安全防火措施,配备满足要求的消防器材。
D.动火作业前,应清理现场,但是监护人必须在动火点10m范围内。
9、在1.8m高乙醇废液储罐上进行管道焊接,需要开具(B)A.高处安全作业证、动火安全作业证、临时用电安全作业证B.动火安全作业证、临时用电安全作业证C.动火安全作业证D.临时用电安全作业证10、特级、一级动火安全作业票有效期不应超过(B );二级动火安全作业票有效期不应超过72h。
[0859]《跨文化交际》第1批[填空题]10. Like the Japanese, the Chinese also prefer written ______ that would appear too general to American or French negotiators.参考答案:10. agreements[填空题]9. The differences in feminine and masculine styles of communication frequently lead to in cross-gender interaction.参考答案:9. gender[填空题]8. Edward Hall alerts us to the invisible aspects of culture and nonverbal communication, which he calls as " language” and "hidden dimension”.参考答案:8. silent[填空题]7. People from cultures schedule several activities at the same time, and time for them is more flexible and more human-centered.参考答案:7. P-time[填空题]6. communication expresses meaning or feeling without words.参考答案:6. Nonverbal[填空题]5. Beauty is only _____ deep.参考答案:5. skin[填空题]4. Understanding and appreciation of differences among cultures in cognitive processing and problem solving is a major step toward successful ______ communication.参考答案:4. intercultural[填空题]3. There is nothing more embarrassing than one's compliments hurting others _____ to different cultural values.参考答案:3. due[填空题]2. The purpose of the greeting is to ______ social contact, not to transfer information.参考答案:4. establish[填空题]1. In daily verbal communication, there are many _____ ways one must observe in order to maintain smooth cross-cultural interaction.参考答案:1. routine[判断题]10. High uncertainty and anxiety hinder effective intercultural communication to a different extent.参考答案:正确[判断题]9. The Eastern view of the universe is characteristically dualistic, materialistic, and lifeless while the Western view is profoundly holistic, dynamic, and spiritual.参考答案:错误[判断题]8. Due to the cultural differences, interpreting in intercultural encounters is possible but difficult.参考答案:正确[判断题]7. Cultural differences can generate positive impacts on negotiation as people can learn from each other.参考答案:错误[判断题]6.A lady might be feminine, masculine or a combination of both.参考答案:正确[判断题]1) 5. Environment is one of the five study areas that nonverbal communication covers.参考答案:正确[判断题]4. "Dragon” means the same to the Westerners as "龙” to the Chinese.参考答案:错误[判断题]3. Sometimes the Chinese way of showing modesty must be considered as fishingfor compliments.参考答案:正确[判断题]2. All cultures require and value politeness, but the ways in which politenessis ` achieved may vary significantly.参考答案:正确[判断题]1. All people of the same nationality will have the same culture.参考答案:错误第2批[论述题]Define the following terms:1. Nonverbal communication2. Body language/Kinesics3. world view4. the Judeo-Christian tradition5. knowledge6. stereotype参考答案:1. Nonverbal communication is the process by which nonverbal behaviors are used, either singly or in combination with verbal behaviors, in the exchange and interpretation of messages within a given situation or context.2. Body language refers to the meaning representing devices as facial expressions and eye behaviors, gestures, and postures.3. A comprehensive world view (or worldview) is the fundamental cognitive orientation of an individual or society encompassing natural philosophy; fundamental existential and normative postulates; or themes, values, emotions, and ethics4. Judeo?Christian (sometimes written as Judaeo?Christian) refers to a set of beliefs and ethics held in common by Judaism and Christianity. It is a common term in American cultural and political rhetoric.5. Knowledge is defined by the Oxford English Dictionary as (i) expertise, and skills acquired by a person through experience or education; the theoretical or practical understanding of a subject; (ii) what is known in a particular field or in total; facts and information; or (iii) awareness or familiarity gained by experience of a fact or situation.6. A stereotype or "stereotypes" is a commonly held public belief about specific social groups or types of individuals. The concepts of "stereotype" and "prejudice" are often confused with many other different meanings. Stereotypes are standardized and simplified conceptions of groups based on some prior assumptions.第3批[论述题]Define the following terms.1. nonverbal communication2. culture shock3. gender4. stereotype5. body language参考答案:1.Nonverbal communication is the process by which nonverbal behaviors are used, either singly or in combination with verbal behaviors, in theexchange and interpretation of messages within a given situation or context.2.Culture shock is precipitated by the anxiety that results from losing all our familiar signs and symbols of social intercourse. The main cause of cultu re shock is displacement from our "home” culture. This lack of common experiences and familiar surroundings creates varying degrees of consequences.3.Gender and sex are not synonymous. Sex is determined by genetics and biology, while gender is produced and reproduced by society. Societies create meanings of gender; in turn, individuals become gendered as they embody social prescriptions in their personal identities.4.Stereotype is a complex form of categorization that mentally organizes our experiences and guides our behavior toward a particular group of people. There are a number of reasons that stereotypes, as a form of classification, hamper intercultural communication.5.Body language refers to the meaning representing devices as facial expressions and eye behaviors, gestures, and postures.[论述题]Analyze the following cases,and then answer the given questions.Case 1How would you explain the Director's behavior toward Katherine? How would you make the Director understand why Katherine felt frustrated and angry?Katherine came to Beijing in 1998 and found a job as an English teacher in a foreign language institute. Soon after her classes began, she found that her students showed no interest in her teaching style. Quite a few of them avoided attending her class. She was feeling quite upset and discouraged so she decided to ask the Director, Prof. Wang reviewed his timetable and suggested they meet at ten o` clock on Thursday morning. When Thursday came, Katherine arrived at Prof. Wang` office at the exactly ten o` clock finding him talking with another teacher in Chinese. Seeing that she had come, Prof. Wang smiled and gestured her to sit down. Katherine sat down and the professor excused himself and continued to talk with the other teacher. After five minutes, he finished hisconversation, and apologized to Katherine, and began to focus his attention on her situation. Prof. Wang showed great concern and asked her what the problem was. Just as she was discussing her problem, another Chinese teacher interrupted, with a form that required the Director` s signature. The Director smiled, apologized to Katherine again, and turned to talk with the Chinese teacher in Chinese. Katherine became impatient, and wondered why their discussion should be interrupted since she had made an appointment. Also, she was upset and frustrated that they continued to speak Chinese in front of her. Although their talk continued, she was apparently unhappy about what had happened.Case 2Why does Jay refuse to ask his professor or classmen to clarify the directions for his paper?Jay is having difficulty in writing a paper for his communication class, because he's not sure what the professor wants. When he mentions this to his friend Ellen, she suggests he ask the professor or a classmen to clarify directions. Jay refuses, saying "I can figure it out on my own”.参考答案:2. In this case, Jay's unwillingness to ask others for help in understanding his assignment is a sign of his masculine emphasis on independence. As some scholars point out rather humorously, men invariably resist asking directions when they are lost in the road while women do not hesitate to ask strangers for help. What we have discussed about gender identity help us understand this difference. Because women initially develop identity within the first relationships have an undertone of danger-they could jeopardize independence. So Jay's refusal to ask others for help reflects the masculine emphasis on maintaining autonomy and not appearing weak or incompetent. Unless Ellen realizes this difference between them, Jay's behavior will continue to baffle her.)[填空题]10.One of the most fundamental ways culture shapes our being is throughexplicit and implicit ________ about our relationship to the nature of the universe and to the non-human natural world.参考答案:10. teachings[填空题]9. Native speakers need to admit that difficulty in understanding _______ also occurs among native speakers and reminds non-native speakers to be open about explanations given.参考答案:9. humor[填空题]8. The American _______ is to conduct business in an efficient manner,while compromises may be part of the outcome.参考答案:8. n orm[填空题]7. The differences in feminine and masculine styles of communication frequently lead to ________in cross-gender interaction.参考答案:7. misunderstanding[填空题]6. communication expresses meaning or feeling without words.参考答案:6. Nonverbal[填空题]5.Understanding and appreciation of differences among cultures in cognitive processing and problem solving is a major step toward successful ______ communication.参考答案: 5. intercultural[填空题]pliments and compliment responses are an _______ part of daily verbal communication.参考答案:4. essential[填空题]3. Being unaware of the difference, intercultural communication ______ occurs here and there.参考答案:3. breakdown[填空题]2. When communicating with each other, each person ___________ and sends messages, and in turn receives and decodes messages.参考答案:2. encodes[填空题]1.Intercultural competence requires sufficient knowledge, suitable _______, and skilled actions.参考答案:1. motivations[单选题]10. The Chinese phrase "知识分子” has the same meaning as "intellectual”.A:TB:F参考答案:B[单选题]9.Although cultural stereotype has its limitations(over-generalization), it still contributes to a person's cultural cognition.A:TB:F参考答案:A[单选题]8.It is very important for nonnative speakers to learn to communicate incomprehension through idiomatic expressions as well as nonverbal gestures.A:TB:F参考答案:A[单选题]7.We should avoid unconsciously adopting our cultural rules and norms in communication in the American or British context.A:TB:F参考答案:A[单选题]6.In Asian cultures, signed agreements are far less important than keeping the interdependent, interwoven organizations involved in a good relationship.A:TB:F参考答案:A[单选题]5. The first and last principle for effective cross-gender communication is suspending judgment.A:TB:F参考答案:A[单选题]4. The social functions of Chinese and English compliments are roughly the same.A:TB:F参考答案:A[单选题]3. There are as many similarities as dissimilarities between English proverbs and Chinese proverbs.A:TB:F参考答案:B[单选题]2. The Chinese way of showing concern is usually appreciated by the Westerners.A:TB:F参考答案:B[单选题]1. Culture is a static entity while communication is a dynamic process.A:TB:F参考答案:B第4批[判断题]8.It is very important for nonnative speakers to learn to communicate incomprehension through idiomatic expressions as well as nonverbal gestures.参考答案:正确[判断题]7.We should avoid unconsciously adopting our cultural rules and norms in communication in the American or British context.参考答案:正确[判断题]5. The first and last principle for effective cross-gender communication is suspending judgment.参考答案:正确[判断题]4. The social functions of Chinese and English compliments are roughly the same.参考答案:正确[判断题]2. The Chinese way of showing concern is usually appreciated by the Westerners.参考答案:错误[判断题]1. Culture is a static entity while communication is a dynamic process.参考答案:错误[判断题]9.Although cultural stereotype has its limitations(over-generalization), it still contributes to a person's cultural cognition.参考答案:正确[论述题]Analyze the following casesCase 1Why did the two Korean interpreters continue to study the Chinese female teachers` trousers?In 1987, a delegation consisting of four Chinese English experts went to Pingyong Foreign Language University to train faculty to be top-level simultaneous interpreters for the 13th International Youth Festival. Of the four experts, two were men and two were women. The two men were dressed in suits with ties and the two women were typically dressed in trousers and their typical business clothes. An authority from Pingyong Foreign Language University and two Korean interpreters greeted them at the Pingyong Railway Station. Surprisingly, while exchanging a few formal remarks, the two interpreters` eyes consistently observed the two Chinese female teachers' trousers. The younger teacher, sensed something and repeatedly checked their trousers and shoes to see if they were dirty or marked. About half an hour later, they arrived at the hotel where they would be staying during their mission. The two interpreters showed eachof them to their rooms to give them an opportunity to freshen up before the formal introductions. In a couple of minutes, the four Chinese teachers gathered in one of the rooms, where the head of the university and the two interpreters introduced themselves further and briefed them on the training program. While talking, the two interpreters seemed to continue to study the two female teachers` trousers. At first, they thought that the Korean interpreters were too embarrassed to look straight in the eyes of a woman. Later this assumption was proved wrong. The four Chinese teachers remained a bit puzzled and did not know what was going on…Case 2Could you explain to Dick why Chen Liang walked into the cafeteria without waiting for him?After graduating from Beijing International Studies University, Chen Liang pursued an MA program at a university in Boston, the U.S. Early in the program, he made friends with some of the American friends, Dick, asked Chen to join him in the university cafeteria. On their way they ran into Dick's girlfriend, Lisa, who was on her way to a lecture. Walking shoulder to shoulder, Dick and Lisa carried on an intimate conversation, as if they hadn't seen each other for ages. Meanwhile, Chen Liang was walking behind them, not taking part in the conversation. When they were nearing the cafeteria Lisa said she had to leave for the lecture. Dick turned away and walked off toward the cafeteria. When Dick looked up, he saw Chen waking into the cafeteria. Dick was puzzled as to why Chen didn't wait for him, and went to the cafeteria alone.参考答案:1. Comment: this is a typical cultural clash between Chinese and Westerners. There is a great difference in the concept of appointment and its behavior pattern in different cultures. To Americans, an appointment is a confirmation to meet at a precise time. If an appointment is scheduled, both parties should respect the appointment time, it should not be interrupted by other things or people. In addition, Westerners are goodtimekeepers; they adhere strictly to schedules. However, Chinese view appointment in a more flexible manner. They are more causal about commitments. This difference in attitudes toward appointment was the roof of Katherine` s unhappiness. Since the Director made a ten o` clock appointment, he should have tried to avoid any interruption. However, when Katherine arrived on time, the Director was still talking with another teacher. When their meeting finally began, it was interrupted again. There is no wonder Katherine became frustrated and angry.2. Suggested answer:In public, the norms of expressing one's feeling and affections toward the opposite sex vary across culture. In Asia and some countries around the Mediterranean Sea, it is acceptable to have body contact between the same sexes in public, but not between the opposite sexes, especially in front of the friends. Chen left because he felt awkward witnessing them hugging and kissing. This shows that Dick knows nothing about the natural response of the Chinese to certain behaviors. Similarly, Chen Liang's behavior shows that he is also in the dark about American behaviors.[填空题]9. In broad terms, nonverbal communication covers four areas: timelanguage (temporal language or chronemics), space language (spatial language or proxemics), language(body movement orkinesics), and paralanguage (voice modulation).参考答案:9. body[论述题]Define the following terms.1. nonverbal communication2. economic globalization3. gender4. linear time5. intercultural communication competence参考答案:1.Nonverbal communication is the process by which nonverbal behaviors are used, either singly or in combination with verbal behaviors, in the exchange and interpretation of messages within a given situation or context.2.No country is the dominant economic force in the world. Economic expansion in globalization has resulted in multinational corporations participating in joint ventures, licensing agreements and other international business arrangements.3.Gender and sex are not synonymous. Sex is determined by genetics and biology, while gender is produced and reproduced by society. Societies create meanings of gender; in turn, individuals become gendered as they embody social prescriptions in their personal identities.4.The West views time either as an arrow or as a moving river that comes from a distant place in the past and goes to an equally distant place in the future. In this linear view of time, history is goal-directed and gradually progressing in a certain direction.5.Intercultural communication competence (ICC competence) is the ability to effectively and appropriately execute communication behaviors to elicit a desired response in a specific environment.[判断题]10. The Chinese phrase "知识分子” has the same meaning as "intellectual”.参考答案:错误[判断题]6.In Asian cultures, signed agreements are far less important than keeping the interdependent, interwoven organizations involved in a good relationship.参考答案:正确[判断题]3. There are as many similarities as dissimilarities between English proverbs and Chinese proverbs.参考答案:错误[填空题]10.According to researchers, there are two primary influences ongender : family communication, particularly betweenmothers and children, and recreational interaction among children.参考答案:10. socialization[填空题]8. Like the Japanese, the Chinese also prefer written ______ that would appear too general to American or French negotiators.参考答案:8. agreements[填空题]7. To develop ________means being able to see things from the point ofview of others so that we can better know and adjust to the other people.参考答案:7. empathy[填空题]6. We need to understand what is ordinarily done in a _______ in order to understand and laugh at messages that are the " out of the ordinary”.参考答案:6. culture[填空题]5.A term in one language does not necessarily have a ______ in the other language.参考答案:5. counterpart[填空题]4.There is nothing more embarrassing than one's compliments hurtingothers _____ to different cultural values.参考答案:4. due[填空题]3.Understanding and appreciation of differences among cultures in cognitive processing and problem solving is a major step toward successful ______ communication.参考答案:3. intercultural[填空题]2.Being unaware of the difference, intercultural communication ______ occurs here and there.参考答案:2. breakdown[填空题]1.Intercultural communication occurs whenever there is communication between people from different cultural ______________.参考答案:1. backgrounds。
作业章节测试题及答案一、选择题(每题2分,共10分)1. 以下哪个选项是正确的?A. 地球是平的B. 地球是圆的C. 地球是三角形的D. 地球是正方形的答案:B2. 光年是用来衡量什么的单位?A. 时间B. 距离C. 速度D. 质量答案:B3. 以下哪个元素是人体必需的微量元素?A. 碳B. 氧C. 铁D. 氢答案:C4. 牛顿第一定律描述的是什么?A. 力是改变物体运动状态的原因B. 物体在没有外力作用下会保持静止或匀速直线运动C. 力是维持物体运动的原因D. 物体在没有外力作用下会改变运动状态答案:B5. 以下哪个国家不是联合国常任理事国?A. 中国B. 法国C. 德国D. 俄罗斯答案:C二、填空题(每题2分,共10分)1. 人体最大的器官是______。
答案:皮肤2. 植物通过______作用将二氧化碳和水转化为葡萄糖和氧气。
答案:光合3. 电流的单位是______。
答案:安培4. 地球的自转周期是______小时。
答案:245. 化学元素周期表中,元素符号为“Ag”的元素是______。
答案:银三、简答题(每题10分,共20分)1. 简述牛顿第二定律的内容。
答案:牛顿第二定律指出,物体的加速度与作用在物体上的合外力成正比,与物体的质量成反比,且加速度的方向与合外力的方向相同。
2. 描述水的三态变化。
答案:水的三态变化包括固态(冰)、液态(水)和气态(水蒸气)。
水在不同的温度和压力下可以在这三种状态之间转换,例如,当温度升高时,冰可以融化成水;当温度继续升高,水可以蒸发成水蒸气。
结束语:以上是本次作业章节测试题及答案,希望同学们认真复习,掌握相关知识点,为即将到来的考试做好准备。
(0229)《商法学(上)》网上作业题及答案1:第一次作业2:第二次作业3:第三次作业4:第四次作业5:第五次作业6:第六次作业1:[单选题]股份有限公司创立大会必须有(),方可举行。
A:全体发起人出席B:全体认股人出席C:代表股份总数过半数的发起人、认股人出席D:发起人、认股人出席人数占总人数的三分之二以上参考答案:C2:[单选题]下列关于商法基本原则的说法,错误的是()A:商法基本原则具有普遍适用意义B:商法基本原则具有指导意义,因而优先于商法规范适用C:商行为的外观主义是维护交易安全原则的体现D:交易形态定型化是促进交易迅捷原则的要求参考答案:B3:[单选题]在商法各项基本原则的含义中,商事活动的公示主义体现了商法的哪一项基本原则的要求?()A:强化商事组织原则B:维护交易安全原则C:促进交易迅捷原则D:维护交易公平原则参考答案:B4:[单选题]股份有限公司设董事会,其成员的人数为( )A:五人至十九人B:三人至十三人C:七人至二十一人D:三人至十一人参考答案:A5:[单选题]根据我国现行公司法规定,有限责任公司注册资本的最低限额为人民币()。
法律、行政法规对有限责任公司注册资本的最低限额有较高规定的,从其规定。
A:2万元B:3万元C:5万元D:10万元参考答案:B6:[单选题]以募集设立方式设立股份有限公司的,发起人认购的股份不得少于公司股份总数的( );但是,法律、行政法规另有规定的,从其规定。
A:20%B:25%C:30%D:35%参考答案:D7:[单选题]根据我国现行公司法规定,在有限责任公司中全体股东的货币出资金额不得低于公司注册资本的( )A:20%B:30%C:35%D:40%参考答案:B8:[单选题]有限责任公司修改公司章程,必须采用何种表决方式才可以通过?()A:全体股东人数的2/3以上B:所有表决权的2/3以上C:出席股东会所有股东人数的2/3以上D:出席股东会所有股东所持表决权的2/3以上参考答案:B9:[单选题]关于公司国籍的确定方式,我国采用的是哪种方式?()A:股东国籍主义B:公司设立行为地主义C:公司设立准据法主义D:兼采公司设立行为地和公司设立准据法主义参考答案:D10:[单选题]公司与合伙的主要区别是()A:公司的营利性B:公司的法人性C:公司的团体性D:公司的合法性参考答案:B11:[单选题]甲公司和乙公司决定合并成立新的公司,名称仍沿用甲公司的名称,下列关于乙公司的债务承担说法正确的是()A:由新成立的甲公司承担B:由乙公司自己承担C:由原来的甲公司承担D:由新成立的甲公司和乙公司承担连带责任参考答案:A12:[单选题]担任破产清算的公司的董事长、经理,对该公司的破产负有个人责任的,自该公司破产清算完结之日起未逾()年的,不能担任公司的董事、监事。
作业测试题及答案一、选择题(每题2分,共10分)1. 以下哪个选项是正确的?A. 地球是平的B. 地球是圆的C. 地球是三角形的D. 地球是正方形的答案:B2. 太阳系中,哪个行星距离太阳最近?A. 土星B. 木星C. 水星D. 火星答案:C3. 以下哪个国家不是联合国安全理事会常任理事国?A. 中国B. 法国C. 德国D. 俄罗斯答案:C4. 人体内最大的器官是什么?A. 心脏B. 肝脏C. 皮肤D. 肺答案:C5. 计算机的二进制系统是基于什么数字?A. 10B. 2C. 8D. 16答案:B二、填空题(每题2分,共10分)1. 光年是一种________单位,用于测量________。
答案:长度;天体间的距离2. 英文字母表中,字母“Z”是第________个字母。
答案:263. 地球上最深的海沟是________。
答案:马里亚纳海沟4. 人体中含量最多的元素是________。
答案:氧5. 国际象棋中,吃掉对方的国王即获得胜利,这种胜利被称为________。
答案:将死三、简答题(每题10分,共20分)1. 请简述牛顿三大运动定律的内容。
答案:牛顿三大运动定律是物理学中描述物体运动的基本定律。
第一定律(惯性定律)指出,静止的物体保持静止,运动的物体保持匀速直线运动,除非受到外力作用。
第二定律(加速度定律)表明,物体的加速度与作用力成正比,与物体质量成反比。
第三定律(作用与反作用定律)说明,对于每一个作用力,总有一个大小相等、方向相反的反作用力。
2. 请解释什么是光合作用,并简述其过程。
答案:光合作用是植物、藻类和某些细菌利用光能将二氧化碳和水转化为葡萄糖和氧气的过程。
这一过程主要发生在植物的叶绿体中,通过光系统吸收光能,激发电子,产生ATP和NADPH。
这些能量和还原力被用来将二氧化碳固定成有机分子,最终生成葡萄糖,同时释放氧气。
结束语:以上是本次作业测试题及答案的全部内容,希望同学们能够通过这些题目加深对相关知识点的理解和掌握。
1:[单选题]"进不来""拿不走""看不懂""改不了""走不脱"是网络信息安全建设的目的。
其中,"拿不走"是指下面那种安全服务()A:数据加密B:身份认证C:数据完整性D:访问控制参考答案:D2:[单选题]以下有关代理服务技术的描述中,正确的是()A:允许内外网间IP包直接交互B:从网络层次看工作在网络层C:通常都是基于硬件实现的D:与包过滤相比速度要慢些参考答案:D3:[单选题]关于防火墙的功能,以下哪一种描述是错误的?()A:防火墙可以检查进出内部网的通信量B:防火墙可以使用应用网关技术在应用层上建立协议过滤和转发功能C:防火墙可以使用过滤技术在网络层对数据包进行选择D:防火墙可以阻止来自内部的威胁和攻击参考答案:D4:[单选题]以下有关防火墙的描述中,错误的是()A:防火墙是一种主动的网络安全防御措施B:防火墙可有效防范外部攻击C:防火墙不能防止内部人员攻击D:防火墙拓扑结构会影响其防护效果参考答案:A5:[单选题]以下指标中,可以作为衡量密码算法加密强度的是()A:计算机性能B:密钥个数C:算法保密性D:密钥长度参考答案:D6:[单选题]下面哪一种算法属于对称加密算法()A:DESB:RSAC:ECCD:DSA参考答案:A7:[单选题]下面哪一种算法属于非对称加密算法()A:AESB:RijindaelC:RSAD:DES参考答案:C8:[单选题]以下哪个选项是对称密钥密码体制的特点()A:加解密速度快B:密钥不需传送C:密钥管理容易D:能实现数字签名参考答案:A9:[单选题]以下协议中,哪种协议利用了握手机制来协商加密方式()A:安全RPCB:SOCK5C:SSLD:MD5参考答案:C10:[单选题]一个好的密码体制,其安全性应仅仅依赖于()A:其应用领域B:加密方式的保密性C:算法细节保密性D:密钥的保密性参考答案:D11:[单选题]下列关于密码学作用的描述中,错误的是()A:加密信息,使非授权用户无法知道消息的内容B:消息接收者能通过加解密来确认消息的来源C:消息接收者能通过密码技术来确认消息在传输中是否被改变D:通过密码学可提供完全的安全保障参考答案:D12:[单选题]下面选项中,使用了公钥密码体制的是()A:SSLB:SOCK5C:KerberosD:MD5参考答案:A13:[单选题]公钥密码是()A:对称密钥技术,有1个密钥B:不对称密钥技术,有2个密钥C:对称密钥技术,有2个密钥D:不对称密钥技术,有1个密钥参考答案:B14:[单选题]加密密钥和解密密钥不同,且从其中一个密钥难以推出另一个密钥,这样的系统称为()A:常规加密系统B:单密钥加密系统C:公钥加密系统D:对称加密系统参考答案:C15:[单选题]下列选项中,不属于HASH算法的是()A:ECCB:MD4C:MD5D:SHA参考答案:A16:[单选题]SHA是指以下哪个专用名词的简称?()A:数字签名算法B:数据加密标准C:安全散列算法D:电子数据交换参考答案:C17:[单选题]抵御电子邮箱入侵措施中,不正确的是:()A:不用生日做密码B:不要使用少于5位的密码C:不要使用纯数字D:自己做服务器参考答案:D18:[单选题]密码分析者知道一些消息的密文,并试图恢复尽可能多的明文,进而推导出密钥,这种攻击被称为()A:惟密文攻击B:已知明文攻击C:选择明文攻击D:选择密文攻击参考答案:A19:[单选题]密码分析者不仅知道一些消息的密文,还知道个别密文块对应的明文,试图推导出加密密钥或算法,这种攻击被称为()A:惟密文攻击B:已知明文攻击C:选择明文攻击D:选择密文攻击参考答案:C20:[单选题]以下哪些做法可以增强用户口令的安全性()A:选择由全英文字母组成的口令B:选择由全数字组成的口令C:选择与自己身份相关的口令,以免忘记D:选择无规律的口令参考答案:C21:[单选题]关于屏蔽子网防火墙,下列说法错误的是()A:屏蔽子网防火墙是几种防火墙类型中最安全的B:屏蔽子网防火墙既支持应用级网关也支持电路级网关C:内部网对于Internet来说是不可见的D:内部用户可以不通过DMZ直接访问Internet参考答案:D22:[单选题]在包过滤技术中,不能作为过滤依据的是()A:源IP地址B:传输层协议C:目的端口D:数据内容参考答案:D23:[单选题]以下加密方式中能同时提供保密性和鉴别性的有()A:A用自己私钥加密报文传给BB:A用自己公钥加密报文传给BC:A用B的公钥加密报文传给BD:A用自己私钥加密报文,再用B的公钥加密报文传给B参考答案:D24:[单选题]防毒系统在哪个阶段可以获得病毒入侵报告()A:扩散预防阶段B:快速响应清除阶段C:评估与恢复阶段D:向领导汇报阶段参考答案:C25:[单选题]下列措施中,哪项不是减少病毒的传染和造成的损失的好办法。
八大特殊作业试题及答案一、选择题(每题5分,共20分)1. 特殊作业中,下列哪项不属于安全操作规程?A. 穿戴防护服B. 使用未经检验的工具C. 配备必要的安全设备D. 遵守操作流程答案:B2. 在进行高温作业时,下列哪项措施是错误的?A. 穿戴隔热服B. 定期检查设备C. 随意丢弃高温物品D. 配备消防器材答案:C3. 以下哪项不是特殊作业的常见类型?A. 高空作业B. 密闭空间作业C. 办公室工作D. 电气作业答案:C4. 特殊作业中,下列哪项不是必要的个人防护装备?A. 安全帽B. 安全鞋C. 耳塞D. 眼镜答案:C二、填空题(每空2分,共20分)1. 在进行特殊作业前,必须进行______。
答案:安全培训2. 特殊作业的作业人员必须持有______。
答案:特种作业操作证3. 特殊作业现场应设置明显的______标志。
答案:安全警示4. 特殊作业完成后,必须进行______。
答案:现场清理5. 特殊作业中,作业人员应定期进行______。
答案:健康检查三、判断题(每题5分,共20分)1. 特殊作业可以由未经培训的人员进行。
()答案:错误2. 特殊作业现场可以不设置安全警示标志。
()答案:错误3. 特殊作业人员不需要定期进行健康检查。
()答案:错误4. 特殊作业中,作业人员可以不穿戴个人防护装备。
()答案:错误四、简答题(每题10分,共20分)1. 简述特殊作业中常见的安全事故类型。
答案:特殊作业中常见的安全事故类型包括坠落、触电、中毒、窒息、火灾、爆炸等。
2. 描述特殊作业中作业人员应遵守的基本安全操作规程。
答案:特殊作业中作业人员应遵守的基本安全操作规程包括:穿戴适当的个人防护装备,使用合格的工具和设备,遵守操作流程和安全规程,进行必要的安全培训,定期进行健康检查,以及在作业前后进行现场清理和检查。
五、案例分析题(20分)某企业在进行高空作业时,由于作业人员未佩戴安全带,导致从高处坠落受伤。
作业考试题库及答案一、选择题(每题2分,共20分)1. 以下哪个选项是正确的?A. 地球是平的B. 地球是圆的C. 地球是三角形的D. 地球是正方形的答案:B2. 光速在真空中的值是多少?A. 299,792公里/秒B. 299,792公里/小时C. 299,792米/秒D. 299,792米/小时答案:C3. 以下哪个国家不是联合国安全理事会的常任理事国?A. 中国B. 法国C. 德国D. 俄罗斯答案:C4. 人体最大的器官是什么?A. 心脏B. 肺C. 肝脏D. 皮肤答案:D5. 以下哪个是化学元素的符号?A. H2OB. CO2C. NaClD. 以上都是答案:D6. 以下哪个是计算机编程语言?A. JavaB. PhotoshopC. ExcelD. PowerPoint答案:A7. 以下哪个是数学中的定理?A. 勾股定理B. 牛顿第一定律C. 相对论D. 欧姆定律答案:A8. 以下哪个是生物分类的等级?A. 种B. 属C. 科D. 以上都是答案:D9. 以下哪个是物理中的单位?A. 牛顿B. 帕斯卡C. 焦耳D. 以上都是答案:D10. 以下哪个是经济学中的概念?A. 供给B. 需求C. 通货膨胀D. 以上都是答案:D二、填空题(每题2分,共20分)1. 地球的赤道周长大约是________公里。
答案:40,0752. 光在真空中的速度大约是________米/秒。
答案:299,792,4583. 联合国安全理事会的常任理事国包括中国、法国、美国、俄罗斯和________。
答案:英国4. 人体最大的器官是________。
答案:皮肤5. 化学元素周期表中,氢的符号是________。
答案:H6. 计算机编程语言Java是由________公司开发的。
答案:Sun Microsystems7. 勾股定理的公式是a² + b² = c²,其中c是________。
气田完修井作业(气井)井下作业专业题库(附答案)一、单选题1、气井和油井工作液比重相对地层压力附加量为( B )。
A、气井0.07~0.1 油井0.03~0.05B、气井0.07~0.15 油井0.05~0.1C、气井0.07~0.1 油井0.03~0.1D、气井0.07~0.15 油井0.03~0.052、某高压气井投产后,套压升至油管压力,套压升高的原是:( D )A、油管不密封B、油管挂不密封C、套管不密封D、以上原因的综合3、对地层压力已显著低于气井的静水柱压力的井,可通过油套压放空后,可直接用( B )压井。
A、生活污水B、修井液C、海水D、加重泥浆4、浅层气井涌的处理方法是( C )。
(1、埋藏深度浅;2.地层极为松散,地层承压能力弱,因此极容易出现漏失;3.防喷器系统未安装,压井处理手段少;4.浅层气发生的突然性,即从预兆至发生所用的时间短暂;5.对人员及钻井平台造成危害大)A、提高泥浆密度B、尽快钻穿浅层气层C、停止钻进,通过分流器,释放地层能量,同时大排量泵入钻井液或海水D、关井求压,准备压井5、气田测试较为严格,尤其关井求恢复压力时,若出现阀门内漏,测得静压数据实为流压,与测试初衷不符,无法满足油藏需求,若是在井下安全阀密封性完好的情况下,要解决阀门内漏所造成的测试数据不准确问题,应采取的措施是( C )。
A、软件模拟校正技术B、外接管汇控制C、采用井下悬挂器携带压力计入井。
6、采气井测试的内容包括( D )。
A、产能测试B、不稳定试井C、稳定试井D、产能试井和不稳定试井7、地层压力大于或等于(B)的油气井被称为高压油气井。
A、57.9 MPaB、68.9MPaC、78.9 MPaD、85 MPa8、在高压气井钢丝作业下入压力计作业时,下放速度一般不宜过快,一般以速度控制在(B)以内为宜。
A、40m/minB、60m/minC、80m/min9、当人的嗅觉迅速钝化而感觉不出H2S存在时,表明H2S浓度已超过( C )。
(0804)《种子学》网上作业题及答案1:第一次2:第二次3:第三次4:第四次5:第五次6:第六次1:[论述题]19、扦样的原则是什么?参考答案:答:扦样应掌握以下原则:(1)扦样最基本原则是扦取的样品要有代表性,即送验样品的品质要代表整个种子批的品质,试验样品的品质能代表送验样品的品质。
(2)种子批各部分的种子类型和品质要基本均匀一致,否则不予扦样。
(3)扦样点应均匀全面地分布在种子堆的各个部位点上。
(4)各扦样点所取样品数量要基本一致,不可或多或少。
(5)扦样工作必须由经过专门训练的技术熟练的人员担任。
2:[论述题]18、种子标准化对农业生产的发展有何重要的意义?参考答案:答:(1)促进农业稳产高产各地经验表明种子标准化是农业增产简单有效的途径。
(2)促进种子质量提高种子标准化的中心是种子质量标准化。
实践证明凡按原(良)种生产技术规程生产的种子质量明显提高。
(3)促进农产品质量提高农产品质量的优劣与种子质量密切有关。
(4)有效地防止杂草、病虫蔓延符合国家标准的高质量种子,通常纯度、净度、发芽力较高,杂草、病虫感染率低。
特别对检疫性杂草和病虫禁止传播,防止其蔓延为害。
并使田间管理方便,有利于机械耕作。
3:[论述题]17、种子标准化的内容有哪些?参考答案:答:种子标准化可包括五方面内容:(1)优良品种标准品种标准就是将某个品种的形态特征和生物学特性及栽培技术要点作出明确叙述和技术规定,为引种、选种、品种鉴定、种子生产、品种合理布局及田间管理提供依据。
(2)原(良)种生产技术规程这是克服农作物优良品种混杂退化,防杂保纯,提高种子质量的有效措施。
(3)种子质量分级标准种子质量优劣直接影响作物产量和产品质量。
衡量种子质量优劣的标准就是种子质量分级标准。
(4)种子检验规程为了使种子检验获得普遍一致和正确的结果,就要制订一个统一的、科学的种子检验方法,即技术规程。
(5)种子包装、运输、贮藏标准种子包装、运输、贮藏标准是保证种子质量,防止机械混杂,保持种子发芽率的重要环节。
作业题参考答案一.思考题3.1 下图中箭头表示转矩与转速的实际方向,试利用电力拖动系统的动力学方程式说明在附图所示的几种情况下,系统可能的运行状态(加速、减速或匀速)。
(a) (b) (c) (d) (e)图3.50 题3.1图答: 由拖动系统的动力学方程式dt dnGD T T L em 3752=−可知:(a)减速(b)减速(c)加速(d)匀速(e)匀速3.2 在起重机提升重物与下放重物过程中,传动机构的损耗分别是由电动机承担还是由重物势能承担?提升与下放同一重物时其传动机构的效率一样高吗?答:3.3 试指出附图中电动机的电磁转矩与负载转矩的实际方向(设顺时针方向为转速n 的正方向)。
(a) (b)(c) (d)图3.51 题3.3图答: 对于图a em T >0 , L T >0,则有动力学方程式的符号规定:em T 顺时针方向,L T 为逆时针方向;电机工作于正向电动状态。
对于图b em T <0 , L T <0,则有动力学方程式的符号规定:em T 逆时针方向,L T 为顺时针方向;电机工作于正向回馈制动状态。
对于图c em T <0 , L T <0,则有动力学方程式的符号规定:em T 逆时针方向,L T 为顺时针方向;电机工作于反向电动状态。
对于图dem T >0 , L T >0,则有动力学方程式的符号规定:em T 顺时针方向,L T 为逆时针方向;电机工作于反向回馈制动状态。
3.4 根据电力拖动系统的稳定运行条件,试判断图3.52中A 、B 、C 三点是否为稳定运行点?图3.52 题3.4图答:根据电力拖动系统的稳定运行条件:可以得出:系统在A 点、B 点是稳定的; C 点是不稳定运行点。
3.5 一般他励直流电动机为什么不能直接起动?采用什么样的起动方法最好? 答:直接起动时启动电流远远大于额定电流。
带来的危害:会带来很大的电流冲击,导致电网电压下降,影响周围其他用电设备的正常运行。
2-1 什么叫流线、流管?流线与迹线有什么区别? 答:流线就是在流场中某一瞬间作出的一条空间曲线, 使这一瞬间在该曲线上各点的流体质 点所具有的速度方向与曲线在该点的切线方向重合。
在流场中经过一封闭曲线 (不是流线 )的所有流线所围成的管状表面,称为流管。
流线是反映流场某瞬时流速方向的曲线。
其是同一时刻, 由不同流体质点组成的。
迹线是同 一质点不同时刻的轨迹线。
在定常流动中,流线形状不随时间改变,流线与迹线重合。
在非 定常流动中,流线的形状随时间而改变,流线与迹线不重合。
2-2 直角坐标系中,流场速度分量的分布为22u 2xy , v 2x y试证过点( 1, 7)的流线方程为22y 2 x 2 48求得,dx dy 222xy 22x 2y积分得 22yxc代入点( 1, 7)求积分常数 c 4822过点( 1, 7)的流线方程为 y 2 x 2 482-3 设流场中的速度大小及流线的表达式为 Vx 2 2xy2y 2 , y 2 2xy 常数求速度分量的表达式。
解:对 y 2 2xy 常数求导,2y dy 2y 2x dy 0,得出 dy y dx dx dx x y根据流线微分方程 dx dy ,得到 u 和 v 的关系,u x y v u v y代入 Vu 2 v 2x 2 2xy 2y 2得 v y求得 u 和 v 的表达式: v y,u x y 或 v y,u x y2-4 求第 2-3 题中速度分量 u 的最大变化率及方向。
rr jk证:根据流线微分方程dx u dy v解:梯度矢量 G grad2-6 在不可压流中,下列哪几个流动满足质量守恒条件? a ) u3 x sin yv 23x cosy b ) u 3x sin y v 23x cosy c ) u 2rsin cos v2rsin 2d )Vk22xy 2常数r证:divVu x vyw zdrrdx rcos ,y rsin ,V r,Vdtdtdxudt V r cos V sinv dy V r sin V cosdtu u ruu u sincosxr xxrrvv rvv v cossinyryyrruV ruVrcos , sin V r( sinV cos )r rv V rvVrsin , cos V r( cosV sin )rruvV r 2V r 2V 2V r 2V r 2V 2 V r V rVcossinsinsin cos cosxyrrrr rrr r rV rru (x y) ur G grad u r u rrri j(i j) xyG22-5 试证在柱坐标系( r, ,z )下,速度的散度表达式为divV代入 divV u vxyV r1(V r rVw )z解:对于不可压缩流体,应满足连续方程xyv3x 2 sin y 3x 2 sin y 0 满足质量守恒条件 y2-7 流体力学具有分速度x2 2 3/ 2y z )y2 2 2 3/ 2(x 2 y 2 z 2)3/ 2z 2 2 2 3/ 2(x 2 y 2 z 2)3/ 2试问该流场是否有旋?如果无旋,求出其速度位函数。
a )b )3x 2sin y 3x 2sin y y0 不满足质量守恒条件c )ur rxy arctan x u cos ru sin2sin cos 2 2r cos 2 2rsin 2sin 2sin 3rvrv sinrv cos2sin 3cos ( 4rsin cos )r2sin 3 4sincos4sin cos不满足质量守恒条件d )对x 22y 2常数 求导,2x 2y d d x y0得出 d dyx根据流线微分方程dx dy uv得到 u 和 v 的关系, v代入 Vu 2 v 2得uky(x3y 2)2m (x 2kx3y 2)23kxy3kxy 52 2 2 (x 2 y 2 )2(x 25y 2)20 满足质量守恒条件(x 2解:判定无旋流的条件: x 0, y 0, z 0uv同理vz该流场无旋12 2 2 2 (x2 y2z 2)22-8 有不可压流体作定常运动,其速度场为u ax v ay2az式中 a 为常数。
求:( 1) 线变形率、角变形率; ( 2) 流场是否有旋;( 3) 是否有速度位函数存在。
解:微团线变形速率xux a yva yzw 2az微团角变形速率3xyx 2 2 (x y 5z 2)2(x 23xy52 22 y z ) 2对于无旋流,速度位函数udx vdy wdzxdx ydy zdz (x 23z 2)21 wv 0xx2 yz1u w 0 y2 z x 1vuzz2 xyx ( ) 0 同理 y 0, z 0 2 x y该流场无旋解:对 x 2y4求导,得出 dy 2y (2, 1) 1,dx xv u cos(x,s) vcos(y,s) ucos vsin22-10 设下 列几种 函数分 别代表流动的 3 个分速度:(1) u kx,vky, 0; (2) u kx,v ky,kx ; (3) u kx,v ky, kz ; (4) u kx,v ky, 2kz ; (5)u kx,v ky, kz 。
其中 k 常问哪几情况可以代表不可压流动? 解:对于不可压缩流体,应满足连续方程1) u kx,v ky,w 0 ;u2x 22x y , vx 2yxy得到45 , 为 x 轴到切线方向的转角。
对于无旋流,速度位函数 dudx vdy wdz axdx aydy 2azdz12ax2122ay 22az2-9 二维位流流场为量。
3x3 x 2 xy y 2,求曲线 x 2 y4上点( 2,-1 ) 处的切向速度分f (r) cr n (c,n 为任意常数)2-12 二维点涡诱导的无旋流场是否满足连续条件?u xv yw z2)u kx,vky,uvwxyz3) ukx,vky,uvwxyz4) ukx,vky,wuvwxyz5) ukx,vky,wu vwxy z0 可以代表不可压流动 0 可以代表不可压流动 0 不可以代表不可压流动 2kz ;0 可以代表不可压流动 kz 。
0 不可以代表不可压流动 w kx ; w kz ;2-11某一流动可描述为 V f (r), x 2y 2 常数 。
f (r) 应具有什么形式,流场才能满解:对 x 2 2 y 常数 求导, 得出 dy x dx y根据流线微分方程 dx dy uv 代入 V u 2v 2 f (r) yf(r)足连续条件?为什么? ,得到 u 和 v 的关系,2x 2yd d y x12 2 2 (x 2 y 2)2(x 2xf(r) 1y 2)2要满足质量守恒条件,需v0 y流速只有Vr 2 01,V rruv V r 1 V 1V(V r )0 xy r r r满足连续方程u v,满足连续条件x y2-13 某二维流动可描述为V x2 4xy 5y2,y2xy 常数。
试用两种方法证明(见习题副图2-13 )图中对curl z V 在暗影区的面积分等于-4。
证:对y xy常数求导,2y d dy x y x d d y x0得出dydxyx 2y根据流线微分方程dx dy,得到u 和v 的关系,uvx 2yvy代入V u2v2 得v y x2 4xy 5y2求得u 和v 的表达式:v y,u (x 2y)或v y,u x 2y curl z V 为V在z 轴的旋度,同2z 12( v x2x u) 1 y蜒V dsL沿空间封闭曲L(udx vdy) ?L(x 2y)dxmydyL 的环量,等于穿过张在L 上任意曲面S上的涡通量。
(udx vdy) ( v L x u)dS yz dS 4解:二维点涡的位函数2-14 一架飞机以180km/h 的速度在海平面上飞行,求驻点处的表压(即大于或小于大气压的那部分压强)及相对流速为60m/s 处的表压。
解:V1 180km/h 50m/s2-15 有一救火机,见习题附图 2-15 ,出水口直径 7.5cm ,入水口直径 30cm ,流量是 3640L/min(1L=1000 cm 3 ) ,进水口处水压为 2×105 N/m 2。
求救火机所受的反作用力。
解:流量 Q A 1V 1 A 2V 2 , 求得 V 1 =s ,V 2 =s5 已知进口水压 p 1 2 105pa22V 12V 22p 12p 222求得 p 2 1.057 105 pa根据积分形式动量方程 控制体所受合外力等于控制体中动量的增加率加上净流出控制面的动量流量。
F x u V n dS Q(u 2 u 1)SF yv V n dS Q(v 2 v 1)SF x p 1A 1 p 2 A 2 cos30 Q(cos30 V 2 V 1)F y p 2 A 2 sin30 Q sin 30 V 2F x 1.388 104 N F y 649.6NX 方向作用力× 104N ,方向向后, Y 方向作用力,方向向上。
根据 Bernoulli 方程 pV 22p 0p 表1=p 1 p a (p aV1211.225 502 1531.25Pa 2p表2=p表11531.25 11.225 6022673.75Pa。