An investigation on the deformational properties of porous poly(vinyl chloride)and co-poly(butadiene
高三英语大学申请流程单选题30题
高三英语大学申请流程单选题30题1. When filling out the university application form, your full name should be written _____.A. clearlyB. clearC. clarityD. clearing答案:A。
本题考查副词的用法。
clearly 是副词,修饰动词written,表示“清晰地”;clear 是形容词,不能修饰动词;clarity 是名词;clearing 不是合适的形式。
2. In the personal information section of the application, your date of birth must be provided _____.A. exactlyB. exactC. exactnessD. exacting答案:A。
exactly 是副词,修饰动词provided,意为“准确地”;exact 是形容词;exactness 是名词;exacting 不是正确形式。
3. Your contact details, including phone number and email address, should be filled in _____.A. correctlyB. correctC. correctnessD. correcting答案:A。
correctly 是副词,修饰动词filled in,指“正确地”;correct 是形容词;correctness 是名词;correcting 不符合用法。
4. For the question about your nationality, you need to answer _____.A. preciseB. preciselyC. precisenessD. precisian答案:B。
公路隧道病害调查技术规程
公路隧道病害调查技术规程英文回答:Highway tunnel disease investigation techniques are an essential part of ensuring the safety and functionality of road tunnels. These techniques involve the systematic assessment and identification of various types of diseases or defects that may affect the tunnel structure or its components.One of the commonly used techniques for tunnel disease investigation is visual inspection. This involves a thorough examination of the tunnel structure, looking for any visible signs of diseases such as cracks, spalling, or water leakage. For example, during a visual inspection, I would carefully examine the tunnel walls, roof, and floor for any cracks or signs of water infiltration.Another technique is the use of non-destructive testing (NDT) methods. These methods allow for the assessment ofthe internal condition of the tunnel without causing any damage. One example of an NDT method is ground-penetrating radar (GPR), which uses electromagnetic waves to detect any anomalies within the tunnel structure. For instance, I would employ GPR to scan the tunnel lining and identify any potential defects or voids.In addition to visual inspection and NDT methods, geotechnical investigations are also crucial in tunnel disease assessment. These investigations involve the collection and analysis of soil and rock samples to determine their properties and stability. For instance, I would conduct geotechnical tests such as triaxial compression tests to evaluate the strength and deformation characteristics of the tunnel's surrounding rock mass.Furthermore, structural health monitoring (SHM) techniques play a vital role in the ongoing assessment of tunnel diseases. SHM involves the use of sensors and monitoring systems to continuously monitor the structural behavior of the tunnel. For example, I would install strain gauges on the tunnel lining to measure any changes instrain levels, which could indicate the presence ofdiseases such as excessive deformation or stress concentration.中文回答:公路隧道病害调查技术规程是确保道路隧道安全和功能的重要组成部分。
2023-2024学年全国全部人教版高考专题英语高考真卷习题及解析
2023-2024学年全国全部人教版高考专题英语高考真卷1.阅读理解第1题.Humans put a heavy pressure on nature, from exploitation(开采)of resources to habitat destruction. It turns out that we're having a bad effect. We're driving other mammals(哺乳动物)to conduct their activities during the night in an effort to avoid humans.A study published by Science found that, on average, mammals across the world have become 1.36 times more active during the night than they've previously been in the past. Translated into percentages, animals that used to divide their activities between day and night have increased their nighttime activities by 68 percent.Gaynor and her colleagues first noticed this phenomenon of the mammals in the research they conducted in Tanzania, Nepal and Canada when they observed that animals in each country were more active at night when they were around people. To determine what kind of effect it was having on themselves, Gaynor's team conducted an analysis, which was a review of previously published studies and reports that contained information in the 24-hour activity patterns of large mammals. These observations of animal behavior were collected using "remote control cameras, GPS and radio collars and direct observation," along with other methods.Additionally, Gaynor explains in a piece for The Conversation about the study that the researchers relied on studies that tracked a variety of behaviors, like "deer activity in and out of the hunting season, bear activity in areas with and without hiking and elephant activity inside protected areas and outside among, rural settlement." Using some data, Gaynor and her team determined the degree to which each species performed activities during the night and factored in whether there was a high or low amount of human disturbance. Finally, 62 species across six continents were tracked in the study, and the results consistently showed an increase in animal activity at night.These changes in habitat were consistent regardless of the type of disturbance. So whether it was hiking or hunting or farming, the very presence of humans resulted in changes in the animals' night behaviors.(1)Why are some animals active during the night?A: To enjoy the nature more freely.B: To search for a new kind of lifestyle.C: To hunt for more food on the farm.D: To get away from the trouble caused by humans.(2)How is Paragraph 2 organized?A: Listing figures.B: Giving examples.C: Making a comparison.D: Analyzing the process.(3)What did Gaynor want to find out according to Paragraph 3?A: How people influenced the animals.B: Whether the previous discovery was true.C: What effects animals' night activities had on themselves.D: How the animals adapted to the life around humans.(4)What led to the changes in the animals' night behaviors?A: The research Gaynor and her team did.B: The existence of humans' activities.C: The changes in their living space.D: The evolution of the mammals themselves.【答案】DACB【解答】(1)D 目的意图题。
学术英语-理工--Unit-2练习答案
3 Identifying topic sentences
for information
Enhancing your academic language
Translate the following sentences from Text 6 into Chinese.
1 就前者来说,玩家按照顺序移动,〔那么〕每个人都了解 其他玩家之前的动作。就后者而言,玩家同时做出动作, 那么不了解其他玩家的动作。
9
3 Identifying topic sentences
for information
Enhancing your academic language
Match the words with their definitions.
23 the optimal (最正确的) method for improving speaking practice
2 当一个人思考别人会如何反响的时候,他必须站在别人的 角度,用和他们一样的思考方式进行思考;一个人不能将 自己的推理强加在别人的身上。
6
3 Identifying topic sentences
for information
Enhancing your academic language Match the words with their definitions.
1 —— d 2 —— f 3 —— i 4 —— b 5 —— h
do your fair share of the work. 8 They threatened him with a(n) lawsuit (诉讼). 9 No difficulty can deter (阻止) us from trying it again. 10 joint together for mutual (相互的) benefits
2024年高考真题和模拟题英语分类汇编:专题01 词类、短语辨析(解析版) (全国通用)
专题01 词类、短语辨析养成良好的答题习惯,是决定成败的决定性因素之一。
做题前,要认真阅读题目要求、题干和选项,并对答案内容作出合理预测;答题时,切忌跟着感觉走,最好按照题目序号来做,不会的或存在疑问的,要做好标记,要善于发现,找到题目的题眼所在,规范答题,书写工整;答题完毕时,要认真检查,查漏补缺,纠正错误。
总之,在最后的复习阶段,学生们不要加大练习量。
在这个时候,学生要尽快找到适合自己的答题方式,最重要的是以平常心去面对考试。
2024年高考真题1.【新课标Ⅰ卷】The latest ___engineering___ (engineer) techniques are applied to create this protective ____57____ (function) structure that is also beautiful. The design features ten steel “sepals (萼片)” made of glass and aluminium (铝).57.【答案】functional【解析】考查形容词。
句意:最新的工程技术被用来创造一个同样美丽的保护功能结构。
空处修饰名词structure,应用形容词作定语functional,符合题意。
故填functional。
2.【新课标Ⅰ卷】In cold weather, the structure stays ____59____ (close) to protect the plants.59.【答案】closed【解析】考查形容词。
句意:然后在寒冷的天气里,这个结构保持关闭,以保护亚热带植物。
空处用于stays 之后作表语,应用形容词closed,表示“紧闭的”,符合题意。
故填closed。
3.【新课标Ⅰ卷】Further, the Silk Route Garden around the greenhouse ____walks____ (walk) visitors through a journey influenced by the ancient Silk Road, by which silk as well as many plant species came to Britain for ____61____ first time.61.【答案】the【解析】考查冠词。
2023年6月全国甲卷英语错题重做二次开发学案-高三英语一轮复习
微阅读突破:错题重做2023年6月全国甲卷英语真题阅读根据学生测试的反映,学生易错阅读B篇细节题和阅读C篇和D篇推理判断题。
学生版B篇:本文是一篇记叙文,文章主要讲述了一位DIY高手Terri Boltonis的技能以及DIY项目可能会在女性群体中变成一种潮流趋势。
Terri, who now rents a house with friends in Wandsworth, South West London, says DIY also saves her from losing any deposit when a tenancy (租期) es to an end. She adds: “I’ve moved house many times and I always like to personalise my room and put up pictures. So, it’s been useful to know how to cover up holes and repaint a room to avoid any charges when I’ve moved out.”6. How did Terri avoid losing the deposit on the house she rented?A. By making it look like before.B. By furnishing it herself.C. By splitting the rent with a roommate.D. By cancelling the rental agreement.(2)分析下划线长难句子结构并翻译成中文。
So, it’s been useful to know how to cover up holes and repaint a room to avoid any charges when I’ve moved out.主干:___________________________________________________________________________________分析:________作形式主语,真正的主语是 _________________________;不定式 to know how to cover up holes and repaint a room作____________状语;when引导______________从句。
2024年1月浙江高考英语卷二次开发试卷0316
2024年1月浙江高考英语卷笔记&反馈练习听力:1.check on a couple of things2.have this blouse washed and pressed______________________________________3.Air travel4.fried rice5.far from it6.get it presented in class tomorrow_____________________________________7.before midday8.put sth in the post9.ask for a makeup test10.midterm exam 11.be on the right track12.You should have e with me._______________________________________13.freezing winter14.give this show a try15.behind the schedule16.the morning rush17. a car crash18.fall in19.be expected to20. a total of up to 200 millimeters of rain______________________________________A篇——音乐剧《汤姆索亚历险记》搬上荧幕1.the good stuff2.fence painting3.graveyard4.be adapted by…5.original musical6. a familiar 一个熟悉的存在/出场7.play leading roles8.be fresh from…9.一名Beechwood高中的高一学生10.in the cast of “Tom Sawyer”11.to his credit12.demonstrate13.downloadableB篇——从亭到迷你社区图书角的变迁1.mean to make an actual phone call2.shelter from the rain3.for its purpose 为了预定的目的4.house 合租房5.spread some throws over the sofa6.The door swung shut.7.managing 经营代理商8. a spare key9.turn into10.folk conducting spring clean11.volumious books12.bother doing sth13.unbeatable pricepoint14.dozens of titles15.get trapped16.connect me with my keys17.keep me 让我娱乐一下(使我不感到无聊)18.contribute toC 篇——人工降雨防冰雹真的好吗?1.the costliest hailstorm (雹暴) costly adj2.hit v. (hit, hit) 同义strike(, )3.suburb n.4.insurance panies5.seed ... with6.downwind7.the cloud seeding8.address public meetings9.in practice10.drought n. flood n.11. a very small percentage of12.given that13.the opposite effect14.scientific proof concerning....15.succeed in winning a lawsuit against cloudseeding panies16.proceed in relative legal safety17.moisture 保存水分18.prevent the (form)of hailstones 预防冰雹的形成19.forecast disaster hailstorms 预测灾难性的冰雹catastrophe 大灾难20.investigate v.21.be opposed to sth .=oppose sth. 反对某事22.resident n.23.Airplanes seed (threaten) storm cells with a chemical (make) small ice crystals fall as rain they can grow into dangerous hailstones.飞机向有威胁的风暴细胞播撒一种化学物质,使小冰晶在变成危险的冰雹之前变成雨落下来。
1999年度全国英语专业四级试题及答案(4)
1999年度全国英语专业四级试题及答案(4)答案与详解TEXT E短文大意:这是一封消费者向汽车生产厂家提出的投诉信。
81. 答案:B【参考译文】这是一封什么信?【试题分析】本题为主旨题。
【详细解答】信的最后一句说”I am afraid I shall report your company to the Consumers’Association.”即我恐怕要将你们公司告到消费者协会,由此可见这是一封投诉信。
TEXT F短文大意:这篇短文介绍的是网上购物的发展趋势。
82.答案:D【参考译文】这篇文章主要是关于什么的?【试题分析】本题为主旨题。
【详细解答】短文首句说”Online shopping (网上购物) has become a major force in retailing this year…”,由此可知本文主题为Online shopping。
TEXT G短文大意:本文介绍的是美国食品和药品管理委员会为保证血液供应质量而颁布的新条例。
83. 答案:C【参考译文】本文讨论的是下列哪一组织的目标?【试题分析】本题为主旨题。
【详细解答】本文第一段说”(FDA) is taking steps to protect the country’s blood supply.”第二段说”The FDA has prodded new rules...new rules are designed to …”,第三、四段是说新条例的措施和目的。
因此本题正确答案为选项C。
TEXT H短文大意:这是一则有关招聘海外劳工的广告。
84. 答案:A【参考译文】这是一则招聘什么人的广告?【试题分析】本题为主旨题。
【详细解答】短文多处提及与工作相关的句子,如”We have jobs in most parts of theworld …”,”We have jobs for teachers, doctors, nurses, engineers, car mechanics and many others.”由此可知,这是一则招聘去海外工作的广告。
COSL英语5-6级词义
COSL英语5-6级单选试题复习A good auditorium礼堂will assure that the sound is able to be heard from every seat.A. superior较高的, 上级的, 上好的, 出众的, 高傲的B. genuine真实的, 真正的, 诚恳的C. audible 听得见的D. contained包含Miss Jones, a reporter for the New York Times, had access to 接触a lot of industries. A. admittance入场权, 准入to B. knowledge about C. contacts in接触D. engagements in Where did she acquire 获得all her wealth?A. gainB. loseC. hideD. stealThe company asked for additional另外的, 附加的, 额外的information.A. certainB. emphatic 用力的, 显著的, 断然的C. furtherD. enchanting迷人的, 迷惑的, 妩媚的Some adult dogs may weigh as much as 200 pounds, but most weigh between 20 and50 pounds.A. mature成熟的, 到期的B. femaleC. specialD. wildThat lunch did not agree with me; I felt nauseated.A. appealB. tranquilize使安静, 使平静C. suitD. crave恳求, 渴望The 管理者governor's aim is to increase state income.A. promiseB. dutyC. proposal 提议, 建议D. goal目的, 目标Insects昆虫thrive兴旺all over, from the hottest deserts沙漠to the snow-clad peaks of lofty高高的mountains.A. silentlyB. totallyC. everywhereD. overhead In the English language, the indication指示, 迹象of gender by inflection has almost disappeared.A.scarcely 几乎不, 简直没有B. nearlyC. only justD. far from Microfilm can hold a large amount of information in a very small storage space becausethe image is stored in reduced form.A. packetB. bookC. quantitiyD. cycle The company issues 出版, 发行an annual 每年的report every March.A. a yearlyB. a comprehensive全面的, 广泛的,C. a finacialD. a productFew executives realize how critically important their appearance外貌, 外观may be to an employer.A. workB. looksC. healthD. attitudes姿势, 态度The Boy Scouts usually sell apple juice in the fall in order to earn money for their activities。
大学英语六级模拟试卷684(题后含答案及解析)
大学英语六级模拟试卷684(题后含答案及解析)题型有:1. Writing 2. Reading Comprehension (Skimming and Scanning) 3. Listening Comprehension 4. Reading Comprehension (Reading in Depth) 5. Cloze 8. TranslationPart I Writing (30 minutes)1.1. 目前很多父母在子女高中毕业前就送他们出国学习2.形成这种趋势的原因3.我对此的看法正确答案:Overseas Study at an Early Age Nowadays, more and more parents are eager to send their children to study abroad before they finish high school by whatever means and at whatever cost. It is quite understandable for parents to send theft children to study overseas because they place high expectations on their children. They are encouraged by the success stories of those who have completed their overseas study. With the development of economy, companies and institutions at home are giving more and more emphasis on overseas experiences, too. Consequently, pursuing overseas study has become a kind of short cut in gaining a better future. Moreover, there is still one underlying reason for this rush-economic reason. The rapid economic progress in the past few years in China has enabled more and more parents to afford the huge cost for their children’s overseas study. As for me, overseas study is surely a helpful way to get both advanced knowledge and necessary experiences, but overseas study at an early age is neither necessary nor beneficial. The students may be too young to either tend for themselves or think for themselves. I do think that overseas study can contribute to one’s self-improvement, but it’s better to be pursued after one has finished his college study at home, when he is more capable of learning and living on his own.Part II Reading Comprehension (Skimming and Scanning) (15 minutes)Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For questions 1-4, mark:Y (for YES) if the statement agrees with the information given in the passage;N (for NO) if the statement contradicts the information given in the passage;NG (for NOT GIVEN)if the information is not given in the passage.The Unpaid Intern, Legal or Not With job openings scarce for young people, the number of unpaid internships (实习) has climbed in recent years, leading federal and state regulators to worry that more employers are illegally using such internships for free labor. Convinced that many unpaid internships violate minimum wage laws, officials in Oregon, California and other states have begun investigations and fined employers. Last year, M. Patricia Smith, then New York’s labor commissioner, ordered investigations into several firms’ internships. Now, as thefederal Labor Department’s top law enforcement official, she and the wage and hour division are stepping up enforcement nationwide. Many regulators say that violations are widespread, but that it is unusually hard to mount a major enforcement effort because interns are often afraid to file complaints. Many fear they will become known as troublemakers in their chosen field, endangering their chances with a potential future employer. The Labor Department says it is cracking down on firms that fail to pay interns properly and expanding efforts to educate companies, colleges and students on the law regarding internships.”If you’re a for-profit employer or you want to pursue an internship with a for-profit employer, there aren’t going to be many circumstances where you can have an internship and not be paid and still be in compliance with the law,”said Nancy J. Leppink, the acting director of the department’s wage and hour division. Ms. Leppink said many employers failed to pay even though their internships did not comply with the six federal legal criteria that must be satisfied for internships to be unpaid. Among those criteria are that the internship should be similar to the training given in a vocational school or academic institution, that the intern does not displace regular paid workers and that the employer “derives no immediate advantage” from the intern’s activities —in other words, it’s largely a benevolent (慈善的) contribution to the intern. No one keeps official count of how many paid and unpaid internships there are, but Lance Choy, director of the Career Development Center at Stanford University, sees definitive evidence that the number of unpaid internships is mushrooming —fueled by employers’ desire to hold down costs and students’ eagerness to gain experience for their resumes. Employers posted 643 unpaid internships on Stanford’s job board this academic year, more than triple the 174 posted two years ago. In 2008, the National Association of Colleges and Employers found that 50 percent of graduating students had held internships, up from the 17 percent shown in a 1992 study by Northwestern University. This means hundreds of thousands of students hold internships each year; some experts estimate that one-fourth to one-half are unpaid. In California, officials have issued guidance letters advising employers whether they are breaking the law, while Oregon regulators have unearthed numerous abuses. “We’ve had cases where unpaid interns really were displacing workers and where they weren’t being supervised in an educational capacity,”said Bob Estabrook, spokesman for Oregon’s labor department. His department recently handled complaints involving two individuals at a solar panel company who received $3,350 in back pay after claiming that they were wrongly treated as unpaid interns. Many students said they had held internships that involved noneducational menial (非技术性的) work. To be sure, many internships involve some unskilled work, but when the jobs are mostly menial, regulators say, it is clearly illegal not to pay interns. One Ivy League student said she spent an unpaid three-month internship at a magazine packaging and shipping 20 or 40 apparel samples a day back to fashion houses that had provided them for photo shoots. At Little Airplane, a Manhattan children’s film company, a New York University (N.Y.U) student who hoped to work in animation during her unpaid internship said she was instead assigned to the facilities department and ordered to wipe the door handles each day to minimize thespread of swine flu. Tone Thyne, a senior producer at Little Airplane, said its internships were usually highly educational and often led to good jobs. Concerned about the effect on their future job prospects, some unpaid interns declined to give their names or to name their employers when they described their experiences in interviews. While many colleges are accepting more moderate- and low-income students to increase economic mobility, many students and administrators complain that the growth in unpaid internships undercuts that effort by favoring well-to-do and well-connected students, speeding their climb up the career ladder. Many less affluent (富裕的) students say they cannot afford to spend their summers at unpaid internships, and in any case, they often do not have an uncle or family golf buddy who can connect them to a prestigious internship. Brittany Berckes, an Amherst senior who interned at a cable news station that she declined to identify, said her parents were not delighted that she worked a summer unpaid. “Some of my friends can’t take these internships and spend a summer without making any money because they have to help pay for their own tuition or help their families with finances,”she said. “That makes them less competitive candidates for jobs after graduation.”Of course, many internships —paid or unpaid —serve as valuable steppingstones that help young people land future jobs. “Internships have become the gateway into the white-collar work force,”said Ross Perlin, a Stanford graduate and onetime unpaid intern who is writing a book on the subject. “Employers increasingly want experience for entry-level jobs, and many students see the only way to get that is through unpaid internships.”Trudy Steinfeld, director of N.Y.U.’s Office of Career Services, said she increasingly had to ride herd on employers to make sure their unpaid internships were educational. She recently confronted a midsize law firm that promised one student an educational $10-an-hour internship. The student complained that the firm was not paying him and was requiring him to make coffee and sweep out bathrooms. Ms. Steinfeld said some industries, most notably film, were known for unpaid internships, but she said other industries were embracing the practice, seeing its advantages. “A few famous banks have called and said, ‘We’d like to do this,’“ Ms. Steinfeld said. “I said, ‘No way. You will not list on this campus.’”Dana John, an N.Y.U. senior, spent an unpaid summer at a company that books musical talent, spending much of her days photocopying, filing and responding to routine e-mail messages for her boss. “It would have been nice to be paid, but at this point, it’s so expected of me to do this for free,” she said. “If you want to be in the music industry mat’s the way it works. If you want to get your foot in the door somehow, this is the easiest way to do it. You suck it up.”The rules for unpaid interns are less strict for non-profit groups like charities because people are allowed to do volunteer work for non-profits. California and some other states require that interns receive college credit as a condition of being unpaid. But federal regulators say that receiving college credit does not necessarily free companies from paying interns, especially when the internship involves little training and mainly benefits the employer. Many employers say the Labor Department’s six criteria need updating because they are based on a Supreme Court decision from 1947, when many apprenticeships (学徒) were for blue-collar production work. Camille A.Olson, a lawyer based in Chicago who represents many employers, said: “One criterion that is hard to meet and needs updating is that the intern doesn’t perform any work to the immediate advantage of the employer. In my experience, many employers agreed to hire interns because there is very strong mutual advantage to both the worker and the employer. There should be a mutual benefit test.”Kathyrn Edwards, a researcher at the Economic Policy Institute and co-author of a new study on internships, told of a female intern who brought a sexual harassment complaint that was dismissed because the intern was not an employee. “A serious problem surrounding unpaid interns is they are often not considered employees and therefore are not protected by employment discrimination laws,” she said.2.Some firms in Oregon and California are investigated because officials believe______.A.they didn’t pay the interns and break the lawB.they refuse to offer job openings to graduatesC.they spend an unusual amount on internshipsD.they recruit too many undergraduates as interns正确答案:A解析:该段提到,Convinced that many unpaid internships violate minimum wage laws,officials in Oregon,California…have begun investigations…,题干中的believe与该句提到的Convinced对应,[A](他们没有给实习生工资,并且违反了法律)是对表原因的宾语从句many unpaid internships violate minimum wage laws 的同义转述,故答案为[A]。
2023年浙江省高考英语真题及答案解析
2023年浙江省高考英语真题及答案解析本试卷共12页。
考试结束后, 将本试卷和答题卡一并交回。
注意事项: 1. 答题前, 考生先将自己的姓名、准考证号码填写清楚, 将条形码准确粘贴在考生信息条形码粘贴区。
2. 选择题必须使用2B铅笔填涂; 非选择题必须使用0.5毫米黑色字迹的签字笔书写, 字体工整、笔迹清楚。
3. 请按照题号顺序在答题卡各题目的答题区域内作答, 超出答题区域书写的答案无效; 在草稿纸、试卷上答题无效。
4. 作图可先使用铅笔画出, 确定后必须用黑色字迹的签字笔描黑。
5. 保持卡面清洁, 不要折叠, 不要弄破、弄皱, 不准使用涂改液、修正带、刮纸刀。
第一部分听力(1-20小题)在笔试结束后进行。
第二部分阅读(共两节,满分50分)第一节(共15小题;每小题2.5分,满分37.5分)阅读下列短文,从每题所给的A、B、C、D四个选项中选出最佳选项。
ABike Rental & Guided ToursWelcome to Amsterdam, welcome to MacBike. You see much more from the seat of a bike! Cycling is the most economical, sustainable and fun way to explore the city, with its beautiful canals, parks, squares and countless lights. You can also bike along lovely landscapes outside of Amsterdam.Why MacBikeMacBike has been around for almost 30 years and is the biggest bicycle rental company in Amsterdam. With over 2,500 bikes stored in our five rental shops at strategic locations, we make sure there is always a bike available for you. We offer the newest bicycles in a wide variety, including basic bikes with foot brake (刹车), bikes with hand brake and gears (排挡), bikes with child seats, and children’s bikes.PricesGuided City ToursThe 2.5-hour tour covers the Gooyer Windmill, the Skinny Bridge, the Rijksmuseum, Heineken Brewery and much more. The tour departs from Dam Square every hour on the hour, starting at 1:00 pm every day. You can buy your ticket in a MacBike shop or book online.1. What is an advantage of MacBike?A. It gives children a discount.B. It of offers many types of bikes.C. It organizes free cycle tours.D. It has over 2,500 rental shops.2. How much do you pay for renting a bike with hand brake and three gears for two days?A. €15.75.B. €19.50.C. €22.75.D. €29.50.3. Where does the guided city tour start?A. The Gooyer, Windmill.B. The Skinny Bridge.C. Heineken Brewery.D. Dam Square.BWhen John Todd was a child, he loved to explore the woods around his house, observing how nature solved problems. A dirty stream, for example, often became clear after flowing through plants and along rocks where tiny creatures lived. When he got older, John started to wonder if this process could be used to clean up the messes people were making.After studying agriculture, medicine, and fisheries in college, John went back to observing nature and asking questions. Why can certain plants trap harmful bacteria (细菌)? Which kinds of fish can eat cancer-causing chemicals? With the right combination of animals and plants, he figured, maybe he could clean up waste the way nature did. He decided to build what he would later call an eco-machine.The task John set for himself was to remove harmful substances from some sludge (污泥). First, he constructed a series of clear fiberglass tanks connected to each other. Then he went around to local ponds and streams and brought back some plants and animals. He placed them in the tanks and waited. Little by little, these different kinds of life got used to one another and formed their own ecosystem. After a few weeks, John added the sludge.He was amazed at the results. The plants and animals in the eco-machine took the sludge as food and began to eat it! Within weeks it had all been digested, and all that was left was pure water.Over the years, John has taken on many big jobs. He developed a greenhouse — like facility that treated sewage (污水) from 1,600 homes in South Burlington. He also designed an eco-machine to clean canal water in Fuzhou, a city in southeast China.“Ecological design” is the name John gives to what he does. “Life on Earth is kind of a box of spare parts for the inventor,” he says. “You put organisms in new relationships and observe what’s happening. Then you let these new systems develop their own ways to self-repair.”4. What can we learn about John from the first two paragraphs?A. He was fond of traveling.B. He enjoyed being alone.C. He had an inquiring mind.D. He longed to be a doctor.5. Why did John put the sludge into the tanks?A. To feed the animals.B. To build an ecosystem.C. To protect the plants.D. To test the eco-machine.6. What is the author’s purpose in mentioning Fuzhou?A. To review John’s research plans.B. To show an ap plication of John’s idea.C. To compare John’s different jobs.D. To erase doubts about John’s invention.7. What is the basis for John’s work?A. Nature can repair itself.B. Organisms need water to survive.C. Life on Earth is diverse.D. Most tiny creatures live in groups.CThe goal of this book is to make the case for digital minimalism, including a detailed exploration of what it asks and why it works, and then to teach you how to adopt this philosophy if you decide it’s right for you.To do so, I divided the book into two parts. In part one, I describe the philosophical foundations of digital minimalism, starting with an examination of the forces that are making so many people’s digital lives increasingly intolerable, before moving on to a detailed discussion of the digital minimalism philosophy.Part one concludes by introducing my suggested method for adopting this philosophy: the digital declutter. This process requires you to step away from optional online activities for thirty days. At the end of the thirty days, you will then add back a small number of carefully chosen online activities that you believe will provide massive benefits to the things you value.In the final chapter of part one, I’ll guide you through carrying out your own digital decl utter. In doing so, I’ll draw on an experiment I ran in 2018 in which over 1,600 people agreed to perform a digital declutter. You’ll hear these participants’ stories and learn what strategies worked well for them, and what traps they encountered that you should avoid.The second part of this book takes a closer look at some ideas that will help you cultivate (培养) a sustainable digital minimalism lifestyle. In these chapters, I examine issues such as the importance of solitude (独处) and the necessity of cultivating high-quality leisure to replace the time most now spend on mindless device use. Each chapter concludes with a collection of practices, which are designed to help you act on the big ideas of the chapter. You can view these practices as a toolbox meant to aid your efforts to build a minimalist lifestyle that words for your particular circumstances.8. What is the book aimed at?A. Teaching critical thinking skills.B. Advocating a simple digital lifestyle.C. Solving philosophical problems.D. Promoting the use of a digital device.9. What does the underlined word “declutter” in paragraph 3 mean?A. Clear-up.B. Add-on.C. Check-in.D.Take-over.10. What is presented in the final chapter of part one?A. Theoretical models.B. Statistical methods.C. Practical examples.D. Historical analyses.11. What does the author suggest readers do with the practices offered in part two?A. Use them as needed.B. Recommend them to friends.C. Evaluate their effects.D. Identify the ideas behind them.DOn March 7, 1907, the English statistician Francis Galton published a paper which illustrated what has come to be known as the “wisdom of crowds” effect. The experiment of estimation he conducted showed that in some cases, the average of a large number of independent estimates could be quite accurate.This effect capitalizes on the fact that when people make errors, those errors aren’t always the same. Some people will tend to overestimate, and some to underestimate. When enough of these errors are averaged together, they cancel each other out, resulting in a more accurate estimate. If people are similar and tend to make the same errors, then their errors won’t cancel each other out. In more technical terms, the wisdom of crowds requires that people’s estimates be indep endent. If for whatever reasons, people’s errors become correlated or dependent, the accuracy of the estimate will go down.But a new study led by Joaquin Navajas offered an interesting twist (转折) on this classic phenomenon. The key finding of the study was that when crowds were further divided into smaller groups that were allowed to have a discussion, the averages from these groups were more accurate than those from an equal number of independent individuals. For instance, the average obtained from the estimates of four discussion groups of five was significantly more accurate than the average obtained from 20 independent individuals.In a follow-up study with 100 university students, the researchers tried to get a better sense of what the group members actually did in their discussion. Did they tend to go with those most confident about their estimates? Did they follow those least willing to change their minds? This happened some of the time, but it wasn’t the dominant response. Most frequently, the groups reported that they “shared arguments and reasoned together.” Somehow, these arguments and reasoning resulted in a global reduction in error. Although the studies led by Navajas have limitations and many questions remain the potential implications for group discussion and decision-making are enormous.12. What is paragraph 2 of the text mainly about?A. The methods of estimation.B. The underlying logic of the effect.C. The causes of people’s errors.D. The design of Galton’s experiment.13. Navajas’ study found that the average accuracy could increase even if ________.A. the crowds were relatively smallB. there were occasional underestimatesC. individuals did not communicateD. estimates were not fully independent14. What did the follow-up study focus on?A. The size of the groups.B. The dominant members.C. The discussion process.D. The individual estimates.15. What is the author’s attitude toward Navajas’ studies?A. Unclear.B. Dismissive.C. Doubtful.D. Approving.第二节(共5小题;每小题2.5分,满分12.5分)阅读下面短文,从短文后的选项中选出可以填入空白处的最佳选项。
2024年高考真题和模拟题英语分类汇编:专题13 书面表达 (解析版) (全国通用)
专题13 书面表达2024年高考真题Writing 1【2024全国甲卷】52. 英语课要求做课堂展示, 请你根据所给图片, 以Development of Transport in China为题写一篇发言稿。
注意:1. 词数100 左右;2. 题目和首句已为你写好。
Development of Transport in ChinaFrom the vehicle of horses to today's convenient transport, Chinese transport has an enormous development._______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _【答案】Development of Transport in ChinaFrom the vehicle of horses to today’s convenient transport, Chinese transport has seen enormous development. Chinese transport has undergone remarkable transformations, giving the Chinese people access to different ways of travelling.Firstly, shared bicycles have emerged as a symbol of urban mobility, offering an affordable and green alternative for short trips. Secondly, the introduction of high-speed trains has dramatically shortened travel times, making intercity travel faster and more comfortable. Lastly, the proliferation of new energy vehicles underscores China’s dedication to environmental sustainability, reducing reliance on fossil fuels. These developments illustrate China’s journey towards a modern and efficient transportation network that balances convenience with environmental responsibility.In short, China’s transport system is embracing innovation and eco-friendliness.【解析】【导语】本篇书面表达属于应用文。
2023年上海高考(新课标)英语试题及答
2023年上海高考(新课标)英语试题及答2023 Shanghai College Entrance Examination (New Standard) English Test Questions and AnswersPart 1: Reading ComprehensionSection ARead the following passage and answer the questions below.The future of work is changing rapidly as technology continues to advance. Automation and artificial intelligence are transforming industries and job roles. While this shift presents opportunities for increased efficiency and productivity, it also brings challenges for workers who may find themselves displaced or needing to retrain for new roles.As automation becomes more prevalent, certain skills will become increasingly valuable in the job market. Critical thinking, adaptability, and problem-solving skills will be crucial for workers to stay competitive. In addition, soft skills such as communication and collaboration will be essential in a world where human interaction remains key.In order to prepare for the future of work, individuals must embrace lifelong learning and be willing to adapt to newtechnologies and ways of working. Companies also have a responsibility to provide training and support for their employees to ensure they are equipped for the changing landscape of work.1. What are some of the challenges that workers may face as technology continues to advance?2. Why are critical thinking and problem-solving skills important for workers in the future job market?3. What can individuals do to prepare for the future of work?Section BRead the passage below and choose the best option to complete each sentence.It is important to ________ with the latest industry trends in order to stay competitive in the job market.A) keep upB) give upC) give inD) catch upPart 2: Listening ComprehensionListen to the audio recording and answer the following questions.1. What is the main topic of the conversation?2. What are two things the speaker mentions that are important for success in the workplace?Part 3: WritingWrite an essay of at least 300 words on the following topic:"Discuss the impact of automation and artificial intelligence on the future of work. What are the potential benefits and challenges of these technologies for workers and industries? How can individuals and companies adapt to the changing landscape of work?"Part 4: SpeakingPrepare a short presentation on the following topic:"Describe a situation in which you had to adapt to a new technology or way of working. What challenges did you face, and how did you overcome them?"Answers:Section A1. Workers may face challenges such as displacement and the need to retrain for new roles as technology advances.2. Critical thinking and problem-solving skills are important in the future job market because they allow workers to adapt to new challenges and find innovative solutions.3. Individuals can prepare for the future of work by embracing lifelong learning and being willing to adapt to new technologies and ways of working.Section B: A) keep upPart 21. The main topic of the conversation is the future of work in relation to technology and automation.2. The speaker mentions that adaptability and continuous learning are important for success in the workplace.Part 3: WritingThe impact of automation and artificial intelligence on the future of work is significant. These technologies have the potential to increase efficiency and productivity in industries, but they also pose challenges for workers who may need to retrain for new roles. Individuals and companies can adapt to thechanging landscape of work by embracing lifelong learning, developing critical thinking skills, and providing training and support for employees.Part 4: SpeakingIn my previous job, I had to adapt to a new software system that was implemented to streamline our workflow. Initially, I faced challenges in learning how to use the software effectively and integrating it into my daily tasks. However, I overcame these challenges by seeking help from colleagues, taking online tutorials, and practicing using the software regularly. Eventually, I became proficient in using the new technology and it significantly improved my efficiency at work.Overall, the future of work is evolving rapidly with the advancement of technology. Workers and industries must adapt to these changes in order to stay competitive and thrive in the modern job market. By developing key skills, embracing lifelong learning, and being open to new ways of working, individuals and companies can navigate the challenges and opportunities presented by automation and artificial intelligence.。
空乘机考英语试题及答案
空乘机考英语试题及答案一、选择题(每题1分,共10分)1. What is the full form of "ICAO"?A. International Civil Aviation OrganizationB. International Commercial Aviation OrganizationC. International Communication and Aviation OrganizationD. International Communication Aviation Organization答案:A2. The flight is scheduled to depart at 18:00. What time isit in 24-hour format?A. 6:00 PMB. 18:00C. 6:00D. 6:00 AM答案:B3. Which of the following is not a reason for a flight delay?A. Weather conditionsB. Technical issuesC. Passenger comfortD. Air traffic control答案:C4. What does "ETA" stand for in aviation terminology?A. Estimated Time of ArrivalB. Estimated Time of AscendC. Estimated Time of ApproachD. Estimated Time of Arrival at Gate答案:A5. The flight attendant must ensure that all passengers have their seat belts fastened before the aircraft takes off. What is the correct term for this action?A. Seat belt sign onB. Seat belt sign offC. Seat belt sign upD. Seat belt sign down答案:A6. What is the most common language used for communication between pilots and air traffic control?A. EnglishB. FrenchC. SpanishD. Russian答案:A7. In case of an emergency landing, passengers are instructed to evacuate the aircraft quickly and orderly. What is the term used for this procedure?A. Emergency evacuationB. Normal evacuationC. Delayed evacuationD. Partial evacuation答案:A8. What does "PAX" commonly refer to in the aviation industry?A. PilotB. PassengerC. PlaneD. Package答案:B9. The term "turbulence" refers to what kind of condition in flight?A. Smooth flightB. Bumpy flightC. Flight with no visibilityD. Flight with extreme speed答案:B10. What is the purpose of the pre-flight safety demonstration?A. To entertain passengersB. To inform passengers about safety proceduresC. To show off the aircraft's featuresD. To introduce the flight crew答案:B二、填空题(每题1分,共5分)11. The standard greeting phrase used by flight attendants is "Welcome _______ board."答案:aboard12. The flight attendant must ensure that all passengers are aware of the _______ before takeoff.答案:safety instructions13. In the event of a sudden loss of cabin pressure, oxygen masks will automatically drop from the _______.答案:ceiling14. The term "cleared for landing" means that the aircraft has been given permission to _______.答案:land15. When serving food and beverages, flight attendants must always ask passengers if they would like to "_____ the seat belt" before serving.答案:fasten三、简答题(每题3分,共6分)16. What are the three main types of weather conditions that can affect a flight?答案:The three main types of weather conditions that can affect a flight are turbulence, thunderstorms, and icing conditions.17. Describe the role of a flight attendant during an in-flight emergency.答案:The role of a flight attendant during an in-flight emergency is to assist passengers in evacuating the aircraft quickly and safely, ensuring that they follow the safety procedures, and providing first aid if necessary.四、阅读理解(每题2分,共8分)阅读以下短文,回答下列问题。
高三英语法律条文解读单选题30题
高三英语法律条文解读单选题30题1.The court issued a/an ______ ordering the defendant to pay damages.A.judgmentB.decisionC.rulingD.opinion答案:C。
“judgment”主要指法庭的判决;“decision”通常指决定;“ruling”有裁决、裁定之意,在这里“法院发布的要求被告支付损害赔偿的”用“ruling”更恰当;“opinion”是意见。
2.In a criminal case, the ______ has the burden of proving guilt beyond a reasonable doubt.A.prosecutorB.defendantC.judgeD.witness答案:A。
“prosecutor”检察官,在刑事案件中检察官有责任在排除合理怀疑的情况下证明有罪;“defendant”被告;“judge”法官;“witness”证人。
3.A person who is found guilty may be sentenced to ______.A.fineB.imprisonmentmunity serviceD.all of the above答案:D。
一个被认定有罪的人可能被判处罚款(fine)、监禁(imprisonment)、社区服务(community service)等。
4.The right to a fair trial is guaranteed by ______.A.the ConstitutionB.statute lawC.case lawmon law答案:A。
公平审判的权利是由宪法(the Constitution)保障的;“statute law”制定法;“case law”判例法;“common law”普通法。
5.Legal documents must be drafted with precision and ______.A.accuracyB.carelessnessC.hasteD.negligence答案:A。
D420
C 851Practice for Estimating Scratch Hardness of CoarseAggregate Particles 3D 75Practice for Sampling Aggregates 4D 653Terminology Relating to Soil,Rock,and ContainedFluids 2D 1194Test Method for Bearing Capacity of Soil for StaticLoad and Spread Footings 2D 1195Test Method for Repetitive Static Plate Load Testsof Soils and Flexible Pavement Components,for Use inEvaluation and Design of Airport and Highway Pave-ments 2D 1196Test Method for Nonrepetitive Static Plate LoadTests of Soils and Flexible Pavement Components,for Usein Evaluation and Design of Airport and Highway Pave-ments 2D 1452Practice for Soil Investigation and Sampling byAuger Borings 2D 1586Test Method for Penetration Test and Split-BarrelSampling of Soils 2D 1587Practice for Thin-Walled Tube Sampling of Soils 2D 2113Practice for Rock Core Drilling,and Sampling ofRock for Site Investigation 2D 2487Classification of Soils for Engineering Purposes(Unified Soil Classification System)2D 2488Practice for Description and Identification of Soils(Visual-Manual Procedure)2D 2573Test Method for Field Vane Shear Test in CohesiveSoil 2D 2607Classification of Peats,Mosses,Humus,and Re-lated Products 2D 3017Test Method for Water Content of Soil and Rock inPlace by Nuclear Methods (Shallow Depth)2D 3213Practices for Handling,Storing,and Preparing SoftUndisturbed Marine Soil 2D 3282Classification of Soils and Soil-Aggregate Mixturesfor Highway Construction Purposes 2D 3385Test Method for Infiltration Rate of Soils in FieldUsing Double-Ring Infiltrometers 2D 3404Guide to Measuring Matric Potential in the VadoseZone Using Tensiometers 2D 3441Test Method for Deep,Quasi-Static,Cone andFriction-Cone Penetration Tests of Soil 2D 3550Practice for Ring-lined Barrel Sampling of Soils 2D 3584Practice for Indexing Papers and Reports on Soiland Rock for Engineering Purposes 2D 4083Practice for Description of Frozen Soils (Visual-Manual Procedure)2D 4220Practices for Preserving and Transporting SoilSamples 2D 4394Test Method for Determining the In Situ Modulusof Deformation of Rock Mass Using the Rigid PlateLoading Method 2D 4395Test Method for Determining the In Situ Modulusof Deformation of Rock Mass Using the Flexible PlateLoading Method 2D 4403Practice for Extensometers Used in Rock 2D 4428Test Methods for Crosshole Seismic Testing 2D 4429Test Method for CBR (California Bearing Ratio)of Soils in Place 2D 4452Methods for X-Ray Radiography of Soil Samples 2D 4506Test Method for Determining the In Situ Modulus of Deformation of Rock Mass Using a Radial Jacking Test 2D 4544Practice for Estimating Peat Deposit Thickness 2D 4553Test Method for Determining the In Situ Creep Characteristics of Rock 2D 4554Test Method for In Situ Determination of Direct Shear Strength of Rock Discontinuities 2D 4555Test Method for Determining Deformability and Strength of Weak Rock by an In Situ Uniaxial Compres-sive Test 2D 4622Test Method for Rock Mass Monitoring Using Inclinometers 2D 4623Test Method for Determination of In Situ Stress in Rock Mass by Overcoring Method—USBM Borehole Deformation Gage 2D 4630Test Method for Determining Transmissivity and Storativity of Low Permeability Rocks by In Situ Mea-surements Using the Constant Head Injection Test 2D 4631Test Method for Determining Transmissivity and Storativity of Low Permeability Rocks by In Situ Mea-surements Using the Pressure Pulse Technique 2D 4633Test Method for Stress Wave Energy Measurement for Dynamic Penetrometer Testing Systems 2D 4645Test Method for Determination of the In Situ Stress in Rock Using the Hydraulic Fracturing Method 2D 4700Guide for Soil Sampling from the Vadose Zone 2D 4719Test Method for Pressuremeter Testing in Soils 2D 4729Test Method for In Situ Stress and Modulus of Deformation Using the Flatjack Method 2D 4750Test Method for Determining Subsurface Liquid Levels in a Borehole or Monitoring Well (Observation Well)2D 4879Guide for Geotechnical Mapping of Large Under-ground Openings in Rock 2D 4971Test Method for Determining the In Situ Modulus of Deformation of Rock Using the Diametrically Loaded 76-mm (3-in.)Borehole Jack 5D 5079Practices for Preserving and Transporting Rock Core Samples 5D 5088Practice for Decontamination of Field Equipment Used at Nonradioactive Waste Sites 5D 5092Practice for Design and Installation of Ground Water Monitoring Wells in Aquifers 5D 5093Test Method for Field Measurement of Infiltration Rate Using a Double-Ring Infiltrometer with a Sealed-Inner Ring 5D 5126Guide for Comparison of Field Methods for Deter-mining Hydraulic Conductivity in the Vadose Zone 5D 5195Test Method for Density of Soil and Rock In-Place at Depths Below the Surface by Nuclear Methods 5E 177Practice for the Use of the Terms Precision and Bias 4Annual Book of ASTM Standards ,V ol 04.03.5Annual Book of ASTM Standards ,V ol04.09.in ASTM Test Methods 6E 380Practice for the Use of the International System ofUnits (SI)(the Modernized Metric System)6G 51Test Method for pH of Soil for Use in CorrosionTesting 7G 57Method for Field Measurement of Soil ResistivityUsing the Wenner Four-Electrode Method 7,83.Significance and Use3.1An adequate soil,rock,and ground water investigationwill provide pertinent information for decision making on oneor more of the following subjects:3.1.1Optimum location of the structure,both vertically andhorizontally,within the area of the proposed construction.3.1.2Location and preliminary evaluation of suitable bor-row and other local sources of construction aggregates.3.1.3Need for special excavating and dewatering tech-niques with the corresponding need for information,even ifonly approximate,on the distribution of soil water content orpore pressure,or both,and on the piezometric heads andapparent permeability (hydraulic conductivity)of the varioussubsurface strata.3.1.4Investigation of slope stability in natural slopes,cuts,and embankments.3.1.5Conceptual selection of embankment types and hy-draulic barrier requirements.3.1.6Conceptual selection of alternate foundation types andelevations of the corresponding suitable bearing strata.3.1.7Development of additional detailed subsurface inves-tigations for specific structures or facilities.3.2The investigation may require the collection of suffi-ciently large soil and rock samples of such quality as to allowadequate testing to determine the soil or rock classification ormineralogic type,or both,and the engineering propertiespertinent to the proposed design.3.3This guide is not meant to be an inflexible description ofinvestigation requirements;methods defined by other ASTMstandards or non-ASTM techniques may be appropriate insome circumstances.The intent is to provide a checklist toassist in the design of an exploration/investigation plan.4.Reconnaissance of Project Area4.1Available technical data from the literature or frompersonal communication should be reviewed before any fieldprogram is started.These include,but are not limited to,topographic maps,aerial photography,satellite imagery,geo-logic maps,statewide or county soil surveys and mineralresource surveys,and engineering soil maps covering theproposed project area.Reports of subsurface investigations ofnearby or adjacent projects should be studied.N OTE 1—While certain of the older maps and reports may be obsoleteand of limited value in the light of current knowledge,a comparison of theold with the new will often reveal valuable information.4.1.1The United States Geological Survey and the geologi-cal surveys of the various states are the principal sources of geologic maps and reports on mineral resources and ground water.4.1.2United States Department of Agriculture Soil Conser-vation Service soil surveys,where available and of recent date,should enable the investigator to estimate the range in soil profile characteristics to depths of 5or 6ft (1.5or 2m)for each soil mapped.N OTE 2—Each soil type has a distinctive soil profile due to age,parent material,relief,climatic condition,and biological activity.Consideration of these factors can assist in identifying the various soil types,each requiring special engineering considerations and treatment.Similar engi-neering soil properties are often found where similar soil profiles characteristics exist.Changes in soil properties in adjacent areas often indicate changes in parent material or relief.4.2In areas where descriptive data are limited by insuffi-cient geologic or soil maps,the soil and rock in open cuts in the vicinity of the proposed project should be studied and various soil and rock profiles noted.Field notes of such studies should include data outlined in 10.6.4.3Where a preliminary map covering the area of the project is desired,it can be prepared on maps compiled from aerial photography that show the ground conditions.The distribution of the predominant soil and rock deposits likely to be encountered during the investigation may be shown using data obtained from geologic maps,landform analysis and limited ground reconnaissance.Experienced photo-interpreters can deduce much subsurface data from a study of black and white,color,and infrared photographs because similar soil or rock conditions,or both,usually have similar patterns of appearance in regions of similar climate or vegetation.N OTE 3—This preliminary map may be expanded into a detailed engineering map by locating all test holes,pits,and sampling stations and by revising boundaries as determined from the detailed subsurface survey.4.4In areas where documentary information is insufficient,some knowledge of subsurface conditions may be obtained from land owners,local well drillers,and representatives of the local construction industry.5.Exploration Plan 5.1Available project design and performance requirements must be reviewed prior to final development of the exploration plan.Preliminary exploration should be planned to indicate the areas of conditions needing further investigation.A complete soil,rock,and ground water investigation should encompass the following activities:5.1.1Review of available information,both regional and local,on the geologic history,rock,soil,and ground water conditions occurring at the proposed location and in the immediate vicinity of the site.5.1.2Interpretation of aerial photography and other remote sensing data.5.1.3Field reconnaissance for identification of surficial geologic conditions,mapping of stratigraphic exposures and outcrops,and examination of the performance of existing structures.5.1.4On site investigation of the surface and subsurface materials by geophysical surveys,borings,or test pits.6Annual Book of ASTM Standards ,V ol 14.02.7Annual Book of ASTM Standards ,V ol 03.02.8The boldface numbers in parentheses refer to the list of references at the end ofthisstandard.5.1.5Recovery of representative disturbed samples for laboratory classification tests of soil,rock,and local construc-tion material.These should be supplemented by undisturbed specimens suitable for the determination of those engineering properties pertinent to the investigation.5.1.6Identification of the position of the ground water table, or water tables,if there is perched ground water,or of the piezometric surfaces if there is artesian ground water.The variability of these positions in both short and long time frames should be considered.Color mottling of the soil strata may be indicative of long-term seasonal high ground water positions.5.1.7Identification and assessment of the location of suit-able foundation material,either bedrock or satisfactory load-bearing soils.5.1.8Field identification of soil sediments,and rock,with particular reference to type and degree of decomposition(for example,saprolite,karst,decomposing or slaking shales),the depths of their occurrence and the types and locations of their structural discontinuities.5.1.9Evaluation of the performance of existing installa-tions,relative to their structure foundation material and envi-ronment in the immediate vicinity of the proposed site.6.Equipment and Procedures for Use in Exploration6.1Pertinent ASTM Standards—Practices D1452,D2113, D4544,D5088,D5092;Method D1586;and Test Methods D4622,D4633,D4750.6.2The type of equipment required for a subsurface inves-tigation depends upon various factors,including the type of subsurface material,depth of exploration,the nature of the terrain,and the intended use of the data.6.2.1Hand Augers,Hole Diggers,Shovels,and Push Tube Samplers are suitable for exploration of surficial soils to depths of3to15ft(1to5m).6.2.2Earth Excavation Equipment,such as backhoes,dra-glines,and drilled pier augers(screw or bucket)can allow in situ examination of soil deposits and sampling of materials containing very large particles.The investigator should be aware of the possiblity of permanent disturbance of potential bearing strata by unbalanced pore pressure in test excavations.6.2.3Soil and rock boring and drilling machines and proof-ing devices may be used to depths of200to300ft in soil and to a much greater depth in rock.6.2.4Well drilling equipment may be suitable for deep geologic exploration.Normally samples are in the form of sand-sized cuttings captured from the returnflow,but coring devices are available.7.Geophysical Exploration7.1Pertinent ASTM Standards—Test Methods D4428and Method G57.7.2Remote sensing techniques may assist in mapping the geological formations and for evaluating variations in soil and rock properties.Satellite and aircraft spectral mapping tools, such as LANDSAT,may be used tofind and map the areal extent of subsurface materials and geologic structure.Interpre-tation of aircraft photographs and satellite imagery can locate and identify significant geologic features that may be indicative of faults and fractures.Some ground control is generally required to verify information derived from remote sensing data.7.3Geophysical survey methods may be used to supplement borehole and outcrop data and to interpolate between holes. Seismic,ground penetrating radar,and electrical resistivity methods can be particularly valuable when distinct differences in the properties of contiguous subsurface materials are indi-cated.7.4Shallow seismic refraction/reflection and ground pen-etrating radar techniques can be used to map soil horizons and depth profiles,water tables,and depth to bedrock in many situations,but depth penetration and resolution vary with local conditions.Electromagnetic induction,electrical resistivity, and induced polarization(or complex resistivity)techniques may be used to map variations in water content,clay horizons, stratification,and depth to aquifer/bedrock.Other geophysical techniques such as gravity,magnetic,and shallow ground temperature methods may be useful under certain specific conditions.Deep seismic and electrical methods are routinely used for mapping stratigraphy and structure of rock in con-junction with logs.Crosshole shear wave velocity measure-ments can provide soil and rock parameters for dynamic analyses.7.4.1The seismic refraction method may be especially useful in determining depth to,or rippability of,rock in locations where successively denser strata are encountered.7.4.2The seismic reflection method may be useful in delineating geological units at depths below10ft(3m).It is not constrained by layers of low seismic velocity and is especially useful in areas of rapid stratigraphic change.7.4.3The electrical resistivity method,Method G57,may be similarly useful in determining depth to rock and anomalies in the stratigraphic profile,in evaluating stratified formations where a denser stratum overlies a less dense stratum,and in location of prospective sand-gravel or other sources of borrow material.Resistivity parameters also are required for the design of grounding systems and cathodic protection for buried structures.7.4.4The ground penetrating radar method may be useful in defining soil and rock layers and manmade structures in the depth range of1to30ft(1⁄3to10m).N OTE4—Surface geophysical investigations can be a useful guide in determining boring or test hole locations.If at all possible,the interpre-tation of geophysical studies should be verified by borings or test excavations.8.Sampling8.1Pertinent ASTM Standards—Practices D75,D1452, D1587,D2113,D3213,D3550,D4220,D5079;Test Method D1586;Methods D4452;and Guide D4700.8.2Obtain samples that adequately represent each subsur-face material that is significant to the project design and construction.The size and type of sample required is depen-dent upon the tests to be performed,the relative amount of coarse particles present,and the limitations of the test equip-ment to be used.N OTE5—The size of disturbed or bulk samples for routine tests may vary at the discretion of the geotechnical investigator,but the following quantities are suggested as suitable for most materials:(a)Visualclassification—50to500g(2oz to1lb);(b)Soil constants and particle size analysis of non-gravelly soil—500g to2.5kg(1to5lb);(c)Soil compaction tests and sieve analysis of gravelly soils—20to40kg(40to 80lb);(d)Aggregate manufacture or aggregate properties tests—50to200 kg(100to400lb).8.3Accurately identify each sample with the boring,test hole,or testpit number and depth below reference ground surface from which it was taken.Place a waterproof identifi-cation tag inside the container,securely close the container, protect it to withstand rough handling,and mark it with proper identification on the outside.Keep samples for natural water content determination in sealed containers to prevent moisture loss.When drying of samples may affect classification or engineering properties test results,protect them to minimize moisture loss.Practices D4220and D5079address the trans-portation of samples fromfield to laboratory.Most of the titles of the referenced standards are self-explanatory,but some need elaboration for the benefit of the users of this guide.8.3.1Practice D75describes the sampling of coarse and fine aggregates for the preliminary investigation of a potential source of supply.8.3.2Practice D1452describes the use of augers in soil investigations and sampling where disturbed soil samples can be used.Depths of auger investigations are limited by ground water conditions,soil characteristics,and equipment used. 8.3.3Test Method D1586describes a procedure to obtain representative soil samples for identification and classification laboratory tests.8.3.4Practice D1587describes a procedure to recover relatively undisturbed soil samples suitable for laboratory testing.8.3.5Practice D2113describes a procedure to recover intact samples of rock and certain soils too hard to sample by Test Method D1586or Practice D1587.8.3.6Practice D3550describes a procedure for the recov-ery of moderately disturbed,representative samples of soil for classification testing and,in some cases,shear or consolidation testing.9.Classification of Earth Materials9.1Pertinent ASTM Standards—Terminology C119;De-scriptive Nomenclature C294;Classifications D2487,D2607, D3282;Practices D2488,D4083.9.2Additional description of samples of soil and rock may be added after submission to the laboratory for identification and classification tests in accordance with one or more ASTM laboratory standards or other applicable references,or both. Section10.6.3discusses the use,for identification and for classification purposes,of some of the standards listed in9.1.10.Determination of Subsurface Conditions10.1Subsurface conditions are positively defined only at the individual test pit,hole,boring,or open cut examined.Condi-tions between observation points may be significantly different from those encountered in the exploration.A stratigraphic profile can be developed by detailed investigations only where determinations of a continuous relationship of the depths and locations of various types of soil and rock can be inferred.This phase of the investigation may be implemented by plotting logs of soil and rock exposures in walls of excavations or cut areas and by plotting logs of the test borings.Then one may interpolate between,and extrapolate a reasonable distance beyond,these logs.The spacing of these investigations should depend on the geologic complexity of the project area and on the importance of soil and rock continuity to the project design. Exploration should be deep enough to identify all strata that might be significantly affected by the proposed use of the site and to develop the engineering data required to allow analysis of the items listed in Section4for each project.N OTE6—Plans for a program of intrusive subsurface investigation should consider possible requirements for permits for installation and proper closure of bore holes and wells at the completion of the investi-gation.10.2The depth of exploratory borings or test pits for roadbeds,airport paving,or vehicle parking areas should be to at least5ft(1.5m)below the proposed subgrade elevation. Special circumstances may increase this depth.Borings for structures,excavations,or embankments should extend below the level of significant stress or ground water influence from the proposed load as determined by subsurface stress analysis.10.3When project construction or performance of the facility may be affected by either previous water-bearing materials or impervious materials that can block internal drainage,borings should extend sufficiently to determine those engineering and hydrogeologic properties that are relevant to the project design.10.4In all borrow areas the borings or test pits should be sufficient in number and depth to outline the required quantities of material meeting the specified quality requirements.10.5Where frost penetration or seasonal desiccation may be significant in the behavior of soil and rock,borings should extend well below the depth fromfinished grade of the anticipated active zone.10.6Exploration records shall be kept in a systematic manner for each project.Such records shall include:10.6.1Description of each site or area investigated.Each test hole,boring,test pit,or geophysical test site shall be clearly located(horizontally and vertically)with reference to some established coordinate system,datum,or permanent monument.10.6.2Logs of each test hole,boring,test pit,or cut surface exposure shall show clearly thefield description and location of each material and any water encountered,either by symbol or word description.Reference to a Munsell color chart designation is a substantial aid to an accurate description of soil and rock materials.N OTE7—Color photographs of rock cores,soil samples,and exposed strata may be of considerable value.Each photograph should include an identifying number or symbol,a date,and reference scale.10.6.3Identification of all soils based on Classification D2487,Practice D2488,Classification D2607,or Practice D4083.Identification of rock materials based on Terminology C119,Descriptive Nomenclature C294,or Practice C851. Classification of soil and rock is discussed in Section9. 10.6.4Location and description of seepage and water-bearing zones and records of piezometric elevations found in each hole,boring,piezometer,or testpit.10.6.5The results and precise locations of in situ test results such as the penetration resistance or vane shear discussed in 8.3,plate load tests,or other in situ test-engineering properties of soils or rock.10.6.6Percentage of core recovery and rock quality desig-nation in core drilling as outlined in8.3.5.10.6.7Graphical presentation offield and laboratory and its interpretation facilitates comprehensive understanding subsur-face conditions.11.In Situ Testing11.1Pertinent ASTM Standards—Test Methods D1194, D1195,D1196,D1586,D2573,D3017,D3441,D3885, D4394,D4395,D4429,D4506,D4553,D4554,D4555, D4623,D4630,D4631,D4645,D4719,D4729,D4971, D5093,D5195,G51;Guides D3404,D5126;and Practice D4403.11.2In situ testing is useful for:(a)measurement of soil parameters in their undisturbed condition with all of the restraining or loading effects,or both,of the surrounding soil or rock mass active,and(b)for rapid or closely spaced measure-ments,or both,of earth properties without the necessity of sampling.Most of the titles of the various referenced standards are self-explanatory,but some need elaboration for the users of this guide.11.2.1Test Method D1586describes a penetration test that has been correlated by many authors with various strength properties of soils.11.2.2Test Method D2573describes a procedure to mea-sure the in situ unit shear resistance of cohesive soils by rotation of a four-bladed vane in a horizontal plane.11.2.3Test Method D3441describes the determination of the end bearing and side friction components of the resistance to penetration of a conical penetrometer into a soil mass. 11.2.4Practice D4403describes the application of various types of extensometers used in thefield of rock mechanics.11.2.5Test Method D4429describes thefield determina-tion of the California Bearing Ratio for soil surfaces in situ to be used in the design of pavement systems.11.2.6Test Method D4719describes an in situ stress-strain test performed on the walls of a bore hole in soil.N OTE8—Other standards for in situ test procedures and automated data collection are being prepared by ASTM Committee D-18for publication at a later date.12.Interpretation of Results12.1Interpret the results of an investigation in terms of actualfindings and make every effort to collect and include all field and laboratory data from previous investigations in the same area.Extrapolation of data into local areas not surveyed and tested should be made only for conceptual studies.Such extrapolation can be done only where geologically uniform stratigraphic and structural relationships are known to exist on the basis of other data.Cross sections may be developed as part of the site characterization if required to demonstrate the site conditions.12.1.1Cross sections included with the presentation of basic data from the investigation should be limited to the ground surface profile and the factual subsurface data obtained at specific exploration locations.Stratigraphic units between the locations of intrusive explorations should only be indicated if supported by continuous geophysical profiles.12.1.2Cross sections showing interpretations of strati-graphic units and other conditions between intrusive explora-tions but without support of continuous geophysical profiles should be presented in an interpretative report appendix or in a separate interpretative report.The interpretive cross sections must be accompanied by notes describing anomalies or other-wise significant variations in the site conditions that should be anticipated for the intended design or construction activities. N OTE9—Additional exploration should be considered if there is not sufficient knowledge to develop interpretative cross sections,with realistic descriptions of anticipated variations in subsurface conditions,to meet project requirements.12.2Subject to the restrictions imposed by state licensing law,recommendations for design parameters can be made only by professional engineers and geologists specializing in the field of geotechnical engineering and familiar with purpose, conditions,and requirements of the study.Soil mechanics,rock mechanics,and geomorphological concepts must be combined with a knowledge of geotechnical engineering or hydrogeology to make a complete application of the soil,rock,and ground water plete design recommendations may require a more detailed study than that discussed in this guide.12.3Delineate subsurface profiles only from actual geo-physical,test-hole,test-pit,or cut-surface data.Interpolation between locations should be made on the basis of available geologic knowledge of the area and should be clearly identi-fied.The use of geophysical techniques as discussed in7.2is a valuable aid in such interpolation.Geophysical survey data should be identified separately from sample data or in situ test data.13.Report13.1Pertinent ASTM Standards—Terminology D653; Practices D3584,E177,E380;and Guide D4879.13.2The report of a subsurface investigation shall include: 13.2.1The location of the area investigated in terms perti-nent to the project.This may include sketch maps or aerial photos on which the test pits,bore holes,and sample areas are located,as well as geomorphological data relevant to the determination of the various soil and rock types.Such data includes elevation contours,streambeds,sink holes,cliffs,and the like.Where feasible,include in the report a geologic map or an agronomic soils map,or both,of the area investigated.13.2.2A description of the investigation procedures,includ-ing all borings and testhole logs,graphic presentation of all compaction,consolidation,or load test data tabulation of all laboratory test results,and graphical interpretations of geo-physical measurements.13.2.3A summary of thefindings obtained under Sections 4,10,and12,using subhead titles for the respective sections and appropriate recommendations and disclaimers for the use of the report.14.Precision and Bias14.1This guide provides qualitative data only;therefore,a precision and bias statement is notapplicable.。
法律英语模拟试题及答案
法律英语模拟试题及答案一、选择题(每题2分,共20分)1. Which of the following is NOT a fundamental principle of contract law?A. Offer and acceptanceB. ConsiderationC. Promissory estoppelD. Mistake of fact2. The term "tort" refers to:A. A breach of contractB. A civil wrongC. A criminal actD. A legal document3. In the context of criminal law, "actus reus" refers to:A. The guilty mindB. The criminal actC. The harm causedD. The punishment imposed4. Which of the following is a type of intellectual property?A. A patentB. A copyrightC. A trademarkD. All of the above5. "Jurisdiction" in legal terms means:A. The power to make a legal decisionB. The area over which the law appliesC. The process of suing someoneD. The legal profession6. A "fiduciary duty" is an obligation that arises when:A. A contract is breachedB. A crime is committedC. A trust is establishedD. A lawsuit is filed7. The doctrine of "res ipsa loquitur" is used to establish:A. The defendant's intentB. The plaintiff's negligenceC. The defendant's negligenceD. The plaintiff's damages8. "Precedent" in legal terms refers to:A. A previous legal decision that can be used to decide similar casesB. A legal principle that is universally acceptedC. A legal document that sets out the facts of a caseD. A legal argument that has been accepted by a court9. A "class action" is a lawsuit brought by:A. A single plaintiff on behalf of a group of peopleB. A group of plaintiffs on behalf of a single personC. A group of plaintiffs on behalf of themselves and othersD. A single plaintiff on behalf of themselves only10. "Probate" is the legal process of:A. Filing a lawsuitB. Administering an estate after deathC. Determining the validity of a willD. Both B and C二、填空题(每题1分,共10分)11. The legal term "_____" refers to the act of formally charging someone with a crime.12. A "_____" is a legal document that outlines the terms and conditions of an agreement between parties.13. "_____" is the legal principle that states that a person cannot be tried or punished twice for the same offense.14. "_____" is a legal remedy that requires the defendant to perform a specific act or to stop performing a certain act.15. "_____" is the process by which a person is released from prison before the end of their sentence, usually under supervision.16. "_____" refers to the legal responsibility to act primarily for the benefit of another person or entity.17. "_____" is a legal term for the right to use a public way for specific purposes, such as crossing another's land.18. "_____" is the legal principle that a person is innocent until proven guilty.19. "_____" is a legal document that provides evidence of a person's identity and citizenship.20. "_____" is the legal process of formally ending a marriage.三、简答题(每题5分,共30分)21. Define "due diligence" in the context of a legaltransaction.22. Explain the concept of "estoppel" in contract law.23. What is the difference between "assault" and "battery" in criminal law?24. Describe the purpose of a "non-compete agreement" in employment law.四、案例分析题(每题5分,共20分)25. John offers to sell his car to Mary for $10,000. Mary agrees to buy the car but later discovers that the car has a serious engine problem that John knew about but did not disclose. Analyze the situation using the principles of contract law.26. Alice is walking her dog in a public park. A stranger, Bob, suddenly throws a rock at the dog, causing it to run away. Alice sues Bob for the emotional distress she suffered as a result. Discuss the legal issues involved in this case.27. Company X is accused of patent infringement by Company Y. Company X claims that they were not aware of the patent and had conducted a thorough search before developing their product. What legal defense might Company X use?28. Jane is a minor who signed a contract with a company to star in a television show. Later, Jane decides she does not want to participate and wants to void the contract. Whatlegal considerations might apply to Jane's situation?五、论述题(每题15。
颗粒增强金属基复合材料的断裂应变
[文章编号]1004-0609(2001)S1-0129-05颗粒增强金属基复合材料的断裂应变①程 羽,郭生武,郭 成,陈金德(西安交通大学机械工程学院,西安710049)[摘 要]研究了应力三轴度、温度、应变速率对颗粒增强金属基复合材料(PRMMCs)断裂应变的影响。
结果显示,高温下PRMMCs的断裂应变对应力三轴度非常敏感,断裂应变和应力三轴度的指数函数exp(1.5σm/ σ)成反比关系。
高温断裂应变值随应变速率的增加呈抛物线形式下降,而随温度的降低呈线性减小。
断口分析显示,高温变形时,材料韧窝的直径随应力三轴度的增大而减小;室温拉伸应力三轴度与韧窝的大小无关。
[关键词]复合材料;应力三轴度;温度;应变速率;断裂应变[中图分类号]TG304 [文献标识码]A 颗粒增强金属基复合材料(PRMMCs)作为一种先进结构材料具有很大的应用前景,各国竞相投入大量的人力、物力进行研究开发[1,2]。
为了使其尽快地实现大规模产业化,迫切需要明确变形条件对材料流动应力的影响,以便制定合理的热加工工艺,设计模具和选择设备,使成形得以顺利进行。
研究结果表明,PRMMCs的断裂机理属微观韧性断裂[3,4],应力三轴度是影响材料断裂的主要因素之一。
目前有关应力三轴度对其塑性变形的影响研究相对较少,大多局限在下列两个方面:一是通过FEM计算光滑试样拉伸过程中增强体颗粒周围的局部拉伸应力及其影响因素[5],但这种方法不能说明局部的应力三轴度对宏观塑性变形的影响;二是通过对光滑拉伸试样施加球应力来研究对其塑性变形的影响,但研究一般限于室温变形,而且是人为的施加球应力,没有考虑试样结构因素的影响。
PRMMCs的塑性加工一般在高温下进行,温度、应变速率、应力三轴度对成形性能影响很大。
本文研究了锻造温度范围内,变形条件(变形温度、变形速度、应力三轴度)对材料断裂应变的影响规律,为进一步研究塑性加工和评价材料的成形性能奠定基础。
专业英语四级模拟试卷389(题后含答案及解析)
专业英语四级模拟试卷389(题后含答案及解析)题型有:1. DICTATION 2. LISTENING COMPREHENSION 3. CLOZE 4. GRAMMAR & VOCABULARY 5. READING COMPREHENSION 6. WRITINGPART I DICTATION (15 MIN)Directions: Listen to the following passage. Altogether the passage will be read to you four times. During the first reading, which will be read at normal speed, listen and try to understand the meaning. For the second and third readings, the passage will be read sentence by sentence, or phrase by phrase, with intervals of 15 seconds. The last reading will be read at normal speed again and during this time you should check your work. You will then be given 2 minute 1.正确答案:Election in the US Elections are the lifeblood of a democracy./ The word democracy literally1 means “the people rule,”an important concept in America’s history./ In America, elections are held every two years for members of Congress./ In these elections, all seats in the House of Representatives and one-third of the Senate seats are up for grabs./ In addition, every four years, voters go to the polls to elect the nation’s president and vice-president./ V oters also regularly cast their ballots for state/ and city government leaders and local school board members./ Sometimes they also have to vote on a proposed law./ In the American electoral system, people don’t really vote for presidential candidates./ Instead, voters cast their ballots for “electors” who support each candidate./ Each state has as many electors as the total number of its representatives in Congress./ This equals two senators per state plus the number of its representatives in the House./ The candidate who has the most votes in a state wins all of the state’s electors./ To win the presidential election, a candidate must gain at least 270 of the 538 total electoral votes.PART II LISTENING COMPREHENSION (20 MIN)Directions: In Sections A, B and C you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.SECTION A CONVERSATIONSDirections: In this section you will hear several conversations. Listen to the conversations carefully and then answer the questions that follow.听力原文:W: What started you in computers?M: I built my first computer when I was in Junior High School. I was an enthusiastic reader. I studied everything I could get my hands on. Then I turned to building my own machine. From that point on, I was hooked.W: Where do you see computers as going in the future?M: This will bethe era of distributed devices, some of which will be in your walls, some of which you will wear, some of which will be in your cars and throughout your house, and maybe one of which will be on your desk. Devices with processors in them will be everywhere, they will be connected, and they will look less like traditional PCs.W: What kind of computer do you have now?M: My primary machine is a heavily loaded PowerMac, which I use to write all my books and to do video editing. I’ve also got a Toshiba notebook which I use for all my work at the company and for email.W: There are critics who say that technology is dangerous and is moving too fast. What’s your reaction?M: There is criticism voiced in every generation. One can’t stop this kind of progress, so the critics you cite above are cursing the dark. That being said, it’s important to always consider the implications of the technology we create, for they have social impact.2.What happened after the man built his first computer?A.He turned to become an enthusiastic reader.B.He went on to build a machine for his Junior High School.C.He became obsessed with computer engineering.D.He was brushed by a hook.正确答案:C解析:本题考查事实。
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pressure-difference across the membrane (Pa); [3 is the membrane porosity; 1 is the membrane thickness (m); A is the membrane surface-area (m2); t is the operational time (s) and k is the Kozeny-Carman constant (m2). The flux J at a given moment t is given by the following relation:
about a drastic change in the membrane permeability. Besides this, the preparation of a membrane from a blend polymer solution always has some disadvantages. 1. To find a common solvent. A good solvent which will individually dissolve each polymer is not necessarily the best common one. Thus the common solvent as well as the concentration ratios for the preparation of a suitable membrane are determined empirically. 2. The physico-chemical properties of a blend polymer solution are not additive quantities. The formation of the membrane structure as well as its performance largely depend on every step in the membrane formation process and cannot be predicted theoretically from their individual behaviour. 3. To ensure a homogeneous distribution of ted 15 February 1996
Abstract
Microfiltration membranes from a polymeric composition consisting of poly(vinyl chloride) and co-poly(butadieneacrylonitrile) were prepared. It was found that with an increase in the co-poly(butadiene-acrylonitrile) concentration in the blend, the operating membrane was converted from a viscoelastic material to a purely elastic one. The blend membrane showed better elastic properties under tensile stress than the pure poly(vinyl chloride) membrane did. The enhancement of the mechanical properties due to the addition of the elastomer was accompanied by a small deterioration of the flux.
0376-7388/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved Pll S0376-73 88(96)00068-3
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M.A. Islam et al. / Journal of Membrane Science 118 (1996) 9-15
Keywords: Deformational properties; Porous poly(vinyl chloride); co-Poly(butadiene-acrylonitrile)
1. Introduction
Conventionally plastomers (mainly homopolymers) are used for the preparation of membranes applicable in pressure-driven processes. These membranes satisfy to a large extent the most important requirements of permeability and selectivity. Little attention has been paid to the improvement of the elastic properties of pressure-driven membranes. This property is of the utmost importance during module formation, handling and transport. Most of the membranes prepared by the casting procedure are brittle and liable to fracture. The elastic property of a membrane may easily be improved by the addition of a compatible elastomer. However, elastomers are usually materials for non-porous diffusion membranes and the combination mentioned may bring
M.A. Islam a, R.N. Stoicheva
b, A.
Dimov b
a Chemical Laboratory, "'Anallab A + ", 30 Prof Asen Zlatarov Str., 7000 Rousse, Bulgaria b Department of General Chemical Technology, Higher Institute Of Chemical Technology, 8010 Bourgas, Bulgaria
1 dQ J = -- -A dt
(2)
Thus the tangent (divided by the membrane surface-area) at any point of the curve Q = f ( t ) would give the instantaneous flux through the membrane, k is determined by the following equation:
j o u r n a l of MEMBRANE SCIENCE
ELSEVIER Journal of Membrane Science 118 (1996) 9-15
An investigation on the deformational properties of porous poly( vinyl chloride) and co-poly(butadiene-acrylonitrile) blend membranes
blend. The casting solution may be homogeneous, but in the course of evaporation and coagulation processes, the polymers may coagulate at different times. Thus the influence of an elastomer in the blend could not be simply illustrated keeping the other membrane-forming parameters constant (mainly polymer concentration, evaporation time, temperature of the coagulation bath, etc.). An effort to improve the elastic property might be considered absolutely successful only in the case when a blend membrane with the same permeability and porecharacteristics as those of a membrane prepared from a plastomer has better elastic properties. Such a finding needs a large number of experimental data and still it does not guarantee success. In our investigation, we prepared some membranes from pure poly(vinyl chloride) (PVC), and P V C - c o poly(butadiene-acrylonitrile) (PBA) blend by a casting procedure. Our experiments did not cover the whole possible range of the membrane formation parameters. We chose a number of membranes (prepared under different conditions) with nearly equal permeabilities, and then tried to compare their pore characteristics and deformational properties. The purpose was to study the influence of PBA on the deformational behaviour of the PVC-PBA blend membrane and to determine how much the functional properties were affected and thus to verify the potential of PBA as a co-substrate in PVC microfiltration membranes. It was found that in a narrow range, PBA enhances the elastic properties of a PVC microfiltration membrane without appreciably affecting other functional parameters. The specific nature of the deformation of the PBA-PVC blend membrane under operating condition is also discussed.