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译文（一）THE ACCOUNTING REVIEWV ol. 83, No. 3 2008pp. 823–853市场参与者的杜邦分析的使用马克•t•Soliman华盛顿大学文摘:杜邦分析,一种常见的财务报表分析，依靠于净营业资产收益率的两个乘法组件:利润率和资产周转率。
这两个会计比率衡量不同的构造。
因此,有不同的属性。
之前的研究已经发现,资产周转率的变化是未来收益的变化正相关。
本文全面探讨了杜邦组件和沿着三个维度有助于文学。
首先,本文有助于财务报表分析文献,发现在这个会计信息信号实际上是增量学习会计信号在先前的研究在预测未来收益。
其次,它有助于文学在股票市场上使用的会计信息通过检查眼前和未来的股本回报投资者应对这些组件。
最后,它增加了分析师的文献处理会计信息的再次测试直接和延迟反应的分析师通过同期预测修正以及未来预测错误。
一致的跨市场加入者的两组,结果表明是有用的信息就是明证杜邦组件和股票收益之间的联系以及维度分析师预测。
然而,我发现预测未来预测错误和异常返回信息处理表明似乎没有完成。
平均水平,分析表明杜邦组件代表增量和可行的操作特征信息的公司。
关键词:财务报表分析、杜邦分析、市场回报、分析师预估。
数据可用性:在这项研究中使用的数据是公开的来源显示的文本。
在本文中,我分析杜邦分析中包含的信息是否与股市回报相关和分析师预测。
之前的研究文档组件从杜邦分析,分解的净营业资产收益率为利润率和资产周转率,有解释力对未来盈利能力的变化。
本文增加了文献综合研究投资者和分析师反应杜邦组件三个维度。
首先,它复制先前记录的预测能力和检查是否健壮和增量其他预测已经考虑在文学的存在。
其次,它探讨了使用这些组件的股市投资者通过观察同生和未来收益。
在同时代的长窗协会和短时期限信息测试,结果显示积极联系杜邦组件和股本回报率。
但小未来异常返回交易策略显示的信息可能不完整的处理。
最后,检查当前预测修正由卖方分析师和未来的预测错误。
外文翻译一：Excerptwords to more and more complex phrases. Children learn to listen and to talk long before they learn to read and write. The same sequence should be followed in classroom teaching. Extra difficulty would be created if one would try to develop English reading and writing skills before children can speak the language. In order to be able to speak the language, students need to know some vocabulary first. In this paper I will focus on how to teach vocabulary that enables students to construct a rich vocabulary bank. Guiding methods are introduced and sample activities are provided.II. Main Part1. The Importance of Teaching Vocabulary1.1. Vocabulary Development in the Primary GradesThe findings of the “National Reading Panel” indicate that vocab ulary instruction does lead to gains in comprehension, but that methods must be appropriate to the age and ability of the reader. Using both indirect and direct teaching methods to build students’ oral and reading vocabularies should be a part of a balanced reading program. Indirect methods would include read-alouds, shared reading and writing experiences, and independent reading. Direct teaching of vocabulary should respond to the needs of the students and should actively engage them in the process(National Reading Panel, 2000).All word learning tasks are not equal in difficulty. A child may understand the concept behind a word, but not know the word itself. For example, the word cease represents a known concept to most children; however, a young child has probably not heard this word used for stop.Learning a new word that represents a known concept is not as difficult as learning a new word that represents a new concept. Teachers in the primary grades introduce many new concepts, and direct instruction is necessary to build up the understanding of these concepts and the vocabulary words that represent them.When teaching vocabulary words that represent known concepts, the emphasis should always be on the context in which the word appears. Discussing the meaning2of the word from the context of the reading selection together with supplying a definition of the word will help to build meaning for students. If students are to acquire this word as part of their vocabulary, then they must be given repeated exposure of the word in a variety of contexts. They must also have opportunities to practise using the word in conversation and/or writing.By the time children enter second grade, they are likely to know between 2,000 and 5,000 vocabulary words. This amazing growth continues throughout the elementary years, as most children gain 3,000 - 4,000 new vocabulary words each year that they can read and understand ( Teaching Reading in the 21st Century, 2001). By encouraging independent reading and providing both indirect and direct instruction in vocabulary, students can be helped to develop the vocabulary knowledge they will need for effective comprehension.1.2. Educators View on Teaching Vocabulary"Teaching one word at a time out of context is the worst way of teaching vocabulary, with rapid forgetting almost guaranteed," asserts Frank Smith, author of "The Book of Learning and Forgetting" (1998), recently published by Teachers College Press. According to Smith, people assimilate new vocabulary words from context the first time they read them, "provided that the gist of the material being read is both interesting and comprehensible. Within five more encounters, the word and its conventional meaning are usually firmly established in the mind of the reader."Other educators who share this view add that when reading material isn't instantly interesting or comprehensible, it's the teacher's job to build context by activating students' prior knowledge of the topic. With regard to vocabulary, that means having students identify difficult words themselves and pool their knowledge to get the meaning. Ann Marie Longo, director of the Boys Town Reading Center, argues that teens can't use context effectively when their vocabularies are limited. Limited vocabulary is the most common problem among weak readers she's worked with. Longo begins with indirect instruction in words and their meanings and then provides high-interest opportunities to use the words. Vocabularyexpert Isabel Beck of the University of Pittsburgh embraces both approaches. For her, there are3four ways to learn vocabulary: wide reading, hearing unfamiliar words in speech, direct instruction in words and "gimmicks" to boost students' interest.Beck suggests teachers incorporate difficult words into their classroom routines and encourage students to look for the words in reading outside class. Longo agrees that students need to put new words to use in writing and conversation as well as reading. "For vocabulary instruction to increase comprehension," says Longo, "you have to see those words over and over again" ( When Adolescents Can´t Read: Methods and Materials that Work, 1999).1.3. Memory and Storage SystemsUnderstanding how our memory works might help us create more effective ways to teach vocabulary. Research in the area, cited by Gairns and Redman (1986) offers us some insights into this process. It seems that learning new items involve storing them first in our short-term memory, and afterwards in long-term memory. We do not control this process consciously but there seem to be some important clues to consider. First, retention in short-term memory is not effective if the number of chunks of information exceeds seven. Therefore, this suggests that in a given class we should not aim at teaching more than this number. However, our long-term memory can hold any amount of information.Research also suggests that our “mental lexicon” is highly organised and efficient, and that semantic related items are stored together. Word frequency is another factor that affects storage, as the most frequently used items are easier to retrieve. We can use this information to attempt to facilitate the learning process, by grouping items of vocabulary in semantic fields, such as topics (e.g. types of fruit). Oxford (1990) suggests memory strategies to aid learning, and these can be divided into creating mental linkages (grouping, associating, placing new words into a context), applying images and sounds (using imagery, semantic mapping, using keywords and representing sounds in memory), reviewing in a structured way and employing action (physical response or sensation, using mechanical techniques). The techniques just mentioned can be used to greater advantage if we can diagnose learning style preferences (visual, aural, kinesthetic, tactile) and make students aware of different memory strategies.4Meaningful tasks, however, seem to offer the best answer to vocabulary learning, as they rely on students’ experiences and reality to facilitate learning. More meaningful tasks also require learners to analyse and process language more deeply, which should help them retain information in long-term memory. Forgetting seems to be an inevitable process, unless learners regularly use items they have learnt. Therefore, recycling is vital, and ideally it should happen one or two days after the initial input. After that, weekly or monthly tests can check on previously taught items. The way students store the items learned can also contribute to their success or failure in retrieving them when needed. Most learners simply list the items learnt in chronological order, indicating meaning with translation. This system is far from helpful, as items arede-contextualised, encouraging students to over generalise their usage. It does not allow for additions and refinements nor does it indicate pronunciation. Teachers can encourage learners to use other methods, using topics and categories to organise a notebook, binder or index cards. Meaning should be stored using English as much as possible. Diagrams and word trees can also be used within this topic/categories organisation. The class as a whole can keep a vocabulary box with cards, which can be used for revision/recycling regularly.1.4. Why Vocabulary is ImportantTeachers may wonder why it is important to teach vocabulary. Well, there is a very clear answer to that question, namely that vocabulary is critical to reading success for three reasons, which I will explain now briefly. First of all, comprehension improves when you know what the words mean. Since comprehension is the ultimate goal of reading, you cannot overestimate the importance of vocabulary development. Secondly, words are the currency of communication. A robust vocabulary improves all areas of communication which are listening, speaking, reading and writing. Last but no least, when children and adolescents improve their vocabulary, their academic and social confidence and competence improve, too.In turn, a deficit in vocabulary knowledge causes comprehension problems, and comprehension problems prevent people from improving their vocabulary knowledge on their own. Intensive vocabulary instruction can be effective in turning this situation around. What is required, though, is a clear and deliberate focus on facilitating students’ creation of meaning ful contexts for the word meanings they are learning,5and a frequent and consistent emphasis on helping them make connections to what they already know.1.5. Levels of Word Knowledge“Word knowledge” refers to how well you know the meaning of a word. Research shows that there are three kinds of word knowledge. Firstly, there is a lack of word knowledge where the meaning is completely unfamiliar. Secondly, there is acquired word knowledge where the basic meaning is recognized after some thought. And last, there is established word knowledge where the meaning is easily, rapidly and automatically recognized (Beck, McKeown, and Omanson, 1987). Words from the third category are already established in the personal vocabulary bank and are the words you would use in conversation and writing. Though it’s enough for students to have a surface understanding of some words in a selection, for most words students must have this same established level of knowledge if they are to understand what they are reading (Nagy, Herman, and Anderson, 1985).2. Teaching Vocabulary2.1. Which Words Should be TaughtWhen making instructional decisions as to which words to teach, it is helpful to have a framework for decision-making in this area. Knowing what words to teach is the first step in providing effective vocabulary practice. Graves and Prenn, for instance, classify the words that should be devided into three types, each requiring a higher investment of teacher and learner time for instruction. With words that are already in the student's oral vocabulary, the students need only to identify the written symbol for such a word. When the word is one for which the student has acquired no concept and it appears frequently in the context, the teacher must take time to develop the concept through instruction. When the word is in the student's listening vocabulary, it may be taught though writing experiences and activities. Focus should be on helping students become independent learners; they should be encouraged to become actively involved in selecting words.6I will shortly mention a practical guide that helps teachers to remember the types of words that they should teach explicitly. First of all, there are Type A Words.These words belong to academic language and thecontent areas.Academic language describes the language of schooling,words used across disciplines like genre and glossary. Content area words are specific to the discipline, words like organization in social studies and organism in science. Then there are Type B Words which arethe basics.There are hundreds of high-frequency words. The basics make up a large percentage of students´ reading and writing. Students must be able to read words like the, is, and, are, been and because.The so-called Type C Words are connectors and act as signal words. There may be some overlap with the basic words. Students need to understand the signals for cause and effect relationships, sequence and other important indicators of how text is organized. In Type D Words the D standsfor difficult- words with multiple meanings are a challenge for all students and may be especially so for learners of the English language.When considering words with multiple meanings teachers should also pay attention to the consonant-vowel-consonant words children encounter when first learning to read - for example words like jam and ham.These words have accessible meanings if you think of something you may eat with eggs in the morning (ham) or of the sweet, sticky stuff on toast (jam). But jam also describes a music playing session. So learning to decode should not be meaning-free, but should provide a good opportunity for teaching the meanings of words including multiple ones. This kind of experience with words improves comprehension.At last there are also Type X Words which are the extras. These are the words that will not be encountered frequently but in a certain story or context they are important for decoding meaning. A good example of this type of word is spindle in “Sleeping Beauty.” It is important to the fairy tale, but it is not a very high-utility word. I just tell kids what words like this mean without any special teaching.2.1.1. Basic Functional VocabularyIn order to understand, speak, read and write a language, the students must acquire the basic functional vocabulary. New words are carefully selected, gradually introduced, and graded to make language learning smooth and easy. The following77 of 27 pages - scroll topInformation on this eBookTitleThe Teaching of Vocabulary in the Primary School Foreign Language ClassroomAuthorDaniela PohlYear2003Pages27Archive No.V34883ISBN (eBook)978-3-638-34971-0ISBN (Book)978-3-640-44099-3DOI10.3239/9783638349710File size224 KBLanguageEnglishTagsTeachingVocabularyPrimarySchoolForeignLanguageClassroom翻译部分：国外小学词汇教学（The Teaching of Vocabulary in the Primary School Foreign Language Classroom）摘要：很多词语都变得越来越复杂，拥有很多的词组。
因为学校对毕业论文中的外文翻译并无规定，为统一起见,特做以下要求：1、每篇字数为1500字左右，共两篇；2、每篇由两部分组成:译文+原文.3 附件中是一篇范本，具体字号、字体已标注。
外文翻译（包含原文)(宋体四号加粗）外文翻译一（宋体四号加粗）作者：(宋体小四号加粗）Kim Mee Hyun Director, Policy Research & Development Team，Korean Film Council（小四号）出处：(宋体小四号加粗)Korean Cinema from Origins to Renaissance(P358～P340) 韩国电影的发展及前景（标题：宋体四号加粗）1996～现在数量上的增长(正文:宋体小四）在过去的十年间，韩国电影经历了难以置信的增长。
上个世纪60年代，韩国电影迅速崛起，然而很快便陷入停滞状态,直到90年代以后，韩国电影又重新进入繁盛时期。
在这个时期，韩国电影在数量上并没有大幅的增长，但多部电影的观影人数达到了上千万人次。
1996年，韩国本土电影的市场占有量只有23.1%。
但是到了1998年，市场占有量增长到35。
8%，到2001年更是达到了50%。
虽然从1996年开始，韩国电影一直处在不断上升的过程中，但是直到1999年姜帝圭导演的《生死谍变》的成功才诞生了韩国电影的又一个高峰。
虽然《生死谍变》创造了韩国电影史上的最高电影票房纪录，但是1999年以后最高票房纪录几乎每年都会被刷新。
当人们都在津津乐道所谓的“韩国大片”时，2000年朴赞郁导演的《共同警备区JSA》和2001年郭暻泽导演的《朋友》均成功刷新了韩国电影最高票房纪录.2003年康佑硕导演的《实尾岛》和2004年姜帝圭导演的又一部力作《太极旗飘扬》开创了观影人数上千万人次的时代。
姜帝圭和康佑硕导演在韩国电影票房史上扮演了十分重要的角色。
从1993年的《特警冤家》到2003年的《实尾岛》，康佑硕导演了多部成功的电影。
2.3.2 公制,标准尺寸图梯形齿廓标准同步皮带由聚氨酯与钢或芳纶抗拉元件制成。
符号T代表梯形齿廓标准带。
WHM公司与国内GmbH公司和德国的Hanover公司合作，在1995年前后联合开发了这种同步带。
MULCO团体在德国以Synchroflex为品牌名发行这种同步带，之后又在欧洲发行。
在1997年这种带被标准化了，其标准为DIN772。
这些带遍布世界各地，并可作为成型的环形带，无尽的连接带和开口带使用。
具有梯形齿廓和公制标准尺寸，AT同步带是T型同步带的一个发展。
它们由由聚氨酯与钢或芳纶抗拉元件制成。
与T型同步带先比，AT型同步带有更宽的齿形截面和更强的抗拉构件。
AT型同步带一个特殊的特点是带齿齿隙紧靠带轮槽底座。
德国的MULCO和Hanover公司开发了这种类型的同步带，并在1980年左右以Synchroflex为品牌发行了这种带。
这些带遍布世界各地，并可作为成型的环形带，无尽的连接带和开口带使用。
这些带ISO 13050 标准用符号H表示，也被称为HTD同步带。
HTD代表大扭矩驱动。
这种同步带是由氯丁橡胶与玻璃纤维抗拉元件和聚酰胺纤维织物制成，并由在1973年引领美国市场的Gates公司开发。
曲齿的几何形状是圆形，较大的齿高显然增加了齿承载能力和抗牙跳能力。
这种带在世界各地都可以看到，许多制造商都参与它的生产。
它们也用聚氨酯，任选与钢丝帘线或芳纶抗拉元件制造。
用户可以从无尽的成型带，开口带和连续挤压环形带中选择使用。
这些带ISO 13050 标准用符号R表示，也被称为RPP同步带。
RPP代表橡胶抛物线。
1985年意大利的公司开发了这种双抛物线齿廓的同步带，他们是由氯丁橡胶与玻璃纤维抗拉元件和聚酰胺纤维织物制成。
这种类型的同步带主要发行在欧洲南部，许多制造商都参与它们的生产。
它们也用聚氨酯，任选钢丝帘线或芳纶抗拉元件制造。
用户可以从无尽的成型带，开口带和连续挤压环形带中选择使用。
这些带ISO 13050 标准用符号S表示，也被称为STD同步带。
外文翻译原文“Translation”Translation is the process of converting written text or speech from one language to another. It is a complex task that requires not only fluent proficiency in both languages, but also a deep understanding of the cultural nuances and linguistic intricacies of each language.Translation has been practiced for centuries and has played a crucial role in facilitating communication and fostering cultural exchange between different societies. It allows people who speak different languages to communicate and interact with each other, breaking down barriers and expanding possibilities.There are various types of translation, including literary translation, technical translation, legal translation, and medical translation, among others. Each type requires specific knowledge and skills to accurately convey the meaning and intent of the original text.In addition to linguistic accuracy, a good translator should also strive to capture the style, tone, and nuances of the original text. This involves understanding the cultural and historical context of the text, as well as the intended audience. Often, a translator needs to make decisions about how to adapt the text to the target language while still preserving its essence.Translation can be a challenging and time-consuming process, especially when dealing with complex or specialized subjects. Translators often need to conduct thorough research to ensure accuracy and maintain the integrity of the original text.With the advancement of technology, machine translation has become increasingly popular in recent years. However, while machine translation can provide quick and convenient translations, it often lacks the accuracy and nuance that human translators can offer. Human translators are able to understand the subtleties of language and idiomatic expressions that are often lost in machine translations. Therefore, it is important to rely on human translators, especially for important or sensitive documents.In conclusion, translation is a vital tool in facilitating communication and promoting cultural understanding. It requires not only language proficiency but also a deep understanding of cultural nuances. While machine translation can offer convenience, human translators are essential for accurate and nuanced translations.。
(完整版)PLC中英文资料外文翻译(1)编辑整理：尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布的，发布之前我们对文中内容进行仔细校对，但是难免会有疏漏的地方，但是任然希望（(完整版)PLC中英文资料外文翻译(1)）的内容能够给您的工作和学习带来便利。
同时也真诚的希望收到您的建议和反馈，这将是我们进步的源泉，前进的动力。
本文可编辑可修改，如果觉得对您有帮助请收藏以便随时查阅，最后祝您生活愉快业绩进步，以下为(完整版)PLC中英文资料外文翻译(1)的全部内容。
（完整版）PLC中英文资料外文翻译(1)编辑整理：张嬗雒老师尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布到文库，发布之前我们对文中内容进行仔细校对,但是难免会有疏漏的地方，但是我们任然希望 (完整版)PLC中英文资料外文翻译（1）这篇文档能够给您的工作和学习带来便利。
同时我们也真诚的希望收到您的建议和反馈到下面的留言区，这将是我们进步的源泉，前进的动力。
本文可编辑可修改，如果觉得对您有帮助请下载收藏以便随时查阅，最后祝您生活愉快业绩进步，以下为〈(完整版)PLC中英文资料外文翻译(1)> 这篇文档的全部内容。
可编程控制器技术讨论与未来发展摘自《可编程控制器技术讨论与未来发展》数字媒体系 08165110 多衡随着时代的发展,当今的技术也日趋完善、竞争愈演愈烈；单靠人工的操作已不能满足于目前的制造业前景,也无法保证更高质量的要求和高新技术企业的形象。
人们在生产实践中看到，自动化给人们带来了极大的便利和产品质量上的保证,同时也减轻了人员的劳动强度,减少了人员上的编制.在许多复杂的生产过程中难以实现的目标控制、整体优化、最佳决策等，熟练的操作工、技术人员或专家、管理者却能够容易判断和操作,可以获得满意的效果。
人工智能的研究目标正是利用计算机来实现、模拟这些智能行为,通过人脑与计算机协调工作,以人机结合的模式，为解决十分复杂的问题寻找最佳的途径我们在各种场合看到了继电器连接的控制,那已经是时代的过去，如今的继电器只能作为低端的基层控制模块或者简单的设备中使用到；而PLC的出现也成为了划时代的主题，通过极其稳定的硬件穿插灵活的软件控制,使得自动化走向了新的高潮。
南京邮电大学毕业设计(论文)外文资料翻译学院(系)：经济与管理学院专业：学生姓名：班级学号：外文出处：Journal of Occupational Psychology,1977, Vol.50附件：1.外文资料翻译译文；2.外文原文附件：1.外文资料翻译译文重新评估工作满意度和工作生活质量——詹姆斯.C.泰勒有用的工作满意度的措施在评估工作的特点以及改善工作生活质量中是有问题的。
根据民意调查和组织调查显示，多年以来，虽然在高和稳定的工作满意度水平下，雇员的挫折感和异化迹象却一直在增加。
经过更密切的检查，这似是而非的调查导致的结论是：无论再严谨的工作满意度调查及测量，得到的只是修改工作和减少员工的挫折感方面的没必要的信息。
根据以往的经验以及对工作生活质量的研究表明，为了克服这个缺陷，在测量工作满意度的时候，雇员本身需要更多地参与测量。
工作满意度已经成为一个模糊不清的尴尬概念。
许多代表着工业人文主义利益的社会科学调查员都对工作满意度十分有兴趣，他们建议要去关注和改善人与职位的关系，提高工作满意度。
从20世纪30年代开始，这种关注已经从制造业扩展到服务和文职部门。
然而，我们可以断言，大部分对工作满意度的研究都无法仅通过对工作及工作本身的研究。
历史上曾经有过对工作满意度的研究，这或许可以支持或者攻击现状，这种趋势还将继续下去。
尴尬的是，在对美国雇员的工作满意度的继续调查研究中，用极高的百分比来衡量他们工作的满意程度，而在同一时间内降低对工人的承诺，雇员所表达的通过增加缺勤率（特别是部分周缺勤），罢工（因其他原因除了工资）而拒绝谈判达成的合同以及破坏产品的比率显然变得更大。
雇员异化的这些问题已经提起公众的注意，但是如果公众关注继续增长，为什么雇员安静的绝望与工作越来越被看作是与压力之间的和解，这些事实和精心准备将使对工作满意度的严格调查成为必然。
前言本文的目的是在不减少抽样误差和防范反应的情况下，使用更精密的统计测试，在不同的模式下对满意度数据进行界定和衡量。
注：红色字体表示语句不明白的地方，请求学姐帮忙。
聚亚烷基二醇的化学结构和它们在含水环境中的好氧生物降解性之间的关系简要：使用一组聚合流体，其中包括聚乙二醇、聚丙二烯（PPG）、不同EO/PO 比率的环氧乙烷（EO）的无规共聚物和环氧丙烷（PO），对聚亚烷基醇（PAG）的化学结构和它们的生物降解性之间的关系进行研究以及用PAG的醚和酰基部分封端。
被测试的PAG中有一个均分子量范围在350-3600Da，它们的差异是由其聚合物主链的直链（二醇型）或支链（三元醇型）分子。
PAG的最终生物降解能力是根据ISO14593（CO2顶空试验）用非预曝光（如在OECD310试验）和预曝光（改编）接种物来确定。
带有PPG结构和二元醇或三元醇的EO/PO共聚物，均分子量不超过1000沓的PAG，被认为是易于生物降解的。
他们的最终生物降解可超过60％的限制（根据OECD310测试标准）。
具有共聚结构并且MW值在1000-3600之间的PAG不易生物降解，但它们可以被看做是那些固有的最终降解物。
在PAG结构中EO含量的增长和末端羟基的酰化与羧酸基团有利地影响了他们的生物降解性。
含末端醚基团封端的PAG似乎是耐生物降解的。
关键词生物降解、聚亚烷基二醇、PAG、PPG、封顶PAG、ISO14593。
引言：术语中的聚亚烷基二醇-PAG，以及在相关文献中的PAG，例如，聚乙二醇，聚醚和聚（烯化氧）中使用的PAG术语都是带有环氧化物结构烯化氧聚合得到的化合物。
PAG主要是通过使用乙烯和丙烯的氧化物合成的，不常使用丁二醇和更高的烯烃氧化物。
PAG类化合物（不同的分子量，性能和应用）最常用的包括氧化乙烯或丙烯均聚物氧化物以及乙烯和丙烯氧化物的无规或嵌段共聚物。
PAG的分子结构不仅取决于种类和亚烷基氧化物的比例，而且还取决于用于聚合反应的引发剂分子的类型（单-，二-或多官能分子具有2个以上活泼氢原子）。
引发剂影响PAG分子的末端羟基基团和聚合物链的类型，其可以是线性的（单醇及二醇型）或支链的（多元醇的数类型）。
一曲人性美的田园牧歌———《边城》之美摘要: 沈从文以乡下人的主体视角审视城乡对峙的现状, 热情讴歌了湘西人民的人性美, 描绘了一个瑰丽而温馨的边城世界, 展现出一个诗意的自然环境: 精致柔美而宁静, 远离都市的喧嚣与浮华。
从而提出了他的人与自然和谐共存, 本于自然, 回归自然的哲学。
关键词: 人性美; 田园牧歌; 桃源仙境《边城》是沈从文的代表作, 也是中国现代文学史上优秀的中篇小说之一, 被人们誉为中国现代文学牧歌传说中的顶峰一颗千古不磨的珠玉。
20世纪20年代初, “京派”文人作家群的首席小说家、“乡下人”，沈从文, 从湘西地区的灵山秀水中走出, 以其30年复杂的人生阅历为基础, 通过老船夫、翠翠等人物形象的描绘, 对人类生命与人性的释放形式及其原因进行了探究、认知与感慨, 热情讴歌了湘西人民的人性美。
可以说, 《边城》是沈从文理想人生的缩影, 是一首作家写给故乡的赞美诗, 是作者远离边城而作于都市的梦, 是一曲优美动人的湘西人性美的颂歌。
施蛰存说: “从文处于苗汉杂居的湘西, 他最熟悉的是这一地区的风土人情。
非但熟悉, 而且热爱”。
在沈从文童年记忆中, 存储着一幅理想世界中美丽湘西地域风俗画: 那里的男人豪爽仗义, 刚健顽强; 那里的女人纯朴善良, 热情厚道。
他们重承诺, 守信义, 敢爱敢恨, 对爱情忠贞不渝。
这些普通的山民村妇、痴男怨女和他们的动人故事与美好人性, 便成了沈从文永远的生命崇拜图腾。
由此, 沈从文怀着探究人生“生命的形式”, 抨击否定虚伪人性, 赞美宣示美好人性的初衷, 创作了《边城》。
“有一小溪, 溪边有座白色小塔, 塔下住了一户单独的人家。
这人家只一个老人, 一个女孩子, 一只黄狗。
小溪流下去, 绕山岨流, 约三里便汇入茶峒的大河。
人若过溪越小山走去, 则只一里路就到了茶峒城边。
溪流如弓, 山路如弦, 故远近有了小小差异。
小溪宽约二十丈, 河床为大片石头作成。
静静的水即或深到一篙不能落底, 却依然清澈透明, 河中游鱼来去皆可以计数。
《浅议粉沙质海岸的建港模式》关键词:粉沙;波浪掀沙;沿堤水流;航道淤积;港口平面布置1 引言在研究港口回淤计算以及港口平面布置等问题时,目前一般把海岸划分为两类,一类是淤泥质海岸,一类是沙质海岸,如我国《海港水文规范》对此就有比较明确的规定[1]。
淤泥质海岸的港口航道回淤主要考虑细颗粒泥沙悬沙落淤,目前已经提出了相当多的计算方法和公式[2-4]。
根据多年来对淤泥质海岸的研究,双堤环抱式平面布置方案已成为淤泥质海岸港口建设广泛认可的模式,这种港口布置型式可以有效减少淤泥质海岸的港口淤积,天津新港即为典型实例[5]。
对于沙质海岸,一般认为造成港口航道淤积的主要原因是波浪引起的沿岸输沙,因此针对沿岸输沙的主方向拦截上游来沙的单突堤或者不阻碍沿岸输沙的栈桥-岛堤式布置成为解决港口淤积的主要方案,我国援建的毛里塔尼亚友谊港即是这方面的典型实例[6]。
实际上,根据近年来我国的工程实践和随着泥沙运动特性研究的深入,粉沙质海岸的概念逐渐受到人们的关注。
刘家驹和喻国华将淤泥质海岸航道回淤公式推广到粉沙质海岸[7],张庆河等从泥沙水力特性和运移特征角度对粉沙质海岸进行了界定[8],曹祖德等进一步对粉沙质海岸的定义、泥沙运动推悬比及淤积分析计算等进行了研究[9-11]。
另外一些工作结合实际工程对粉沙质海岸泥沙运动规律进行了分析[12-13]。
从目前的研究结果看,粉沙质海岸泥沙粒径范围基本可以定义在d50为0.03～0.12 mm左右。
粉沙质海岸之所以受到关注,在于粉沙质海岸的港口回淤有其特殊性,骤淤就是其中比较显著的现象之一。
近年来,随着经济的发展,在粉沙质海岸建港已成为比较迫切的要求,一些粉沙质海岸已经建港、正在筹备建港或扩建。
但粉沙质海岸一些已建港口不同程度地存在回淤特别是骤淤现象,使人们对粉沙质海岸的港口建设产生疑虑,采取何种港口布置型式能够有效减少粉沙质海岸港口淤积,已建港口如何整治最为经济有效,成为工程建设急需回答的问题。
虽然最近罗刚和杨希宏[14]、孔令双等[15]以及杨华和麦苗[16]先后对粉沙质海岸港口布置问题进行了讨论,但一些问题仍有待深入认识,为此,本文将在分析粉沙质海岸泥沙运动和航道回淤成因的基础上,探讨粉沙质海岸的建港模式,以期为粉沙质海岸港口设计和港口减淤整治措施提供必要的依据。
2 粉沙质海岸港口回淤成因分析大多数粉沙质海岸具有海滩比较平缓的特点,如京唐港附近海岸为典型的粉沙质海岸,泥沙粒径在0.08 mm左右,海滩坡度在1/400～1/700左右[17];东营港泥沙粒径在0.1 mm左右,也为典型粉沙质海岸,其岸滩坡度在1/1 000～3/1 000左右[16];黄骅港附近海岸虽然从岸滩沉积物的整体特性和粘土颗粒的总量来说,属于淤泥质海岸,但从其海床表层泥沙的粒径(0.03 mm左右)和运动特性来看,应归属于粉沙质淤泥海岸[12],其岸滩坡度在1/2 000左右。
在上述平缓的粉沙质海岸修建港口,为了避免近岸剧烈泥沙运动造成港口航道淤积,大多数港口选择了从岸线开始修建较长的双环抱堤或单引堤加双环抱堤的平面布置型式。
虽然这些港口具有较长的防沙堤,但从近年来的工程实践看,港口外航道仍然可能发生较严重的淤积。
我们将从以下几个方面对粉沙质海岸的回淤机理进行分析。
2.1 波浪的作用在相当多的粉沙质海岸,波浪作用构成了航道回淤的主要诱因。
京唐港出现的几次较为严重的回淤均与大风浪过程有关,如1992年11月,一次东北向大风过程造成防沙堤堤头段航道出现较为严重的集中淤积现象,最大淤厚达到3.2 m; 1993年12月发生的强风浪过程造成外航道集中淤积,最大淤厚达2.5 m[11, 18]。
2003年10月出现的长达两天多的强风暴过程,使京唐港外航道最大淤强超过4 m。
就黄骅港近年来的回淤现象而言,强浪作用下大量表层粉沙质泥沙的悬扬落淤,构成了黄骅港航道淤积的主要模式[12],例如2001年2月、2003年10月等多次强风浪过程均造成了黄骅港外航道的较严重淤积,每次风暴过程造成的外航道淤积总量均达200万m3以上,风暴过程最大骤淤甚至超过600万m3,最大淤厚超过3.5 m。
从上述现象可以得知,粉沙质海岸强淤或骤淤是由波浪引起泥沙大量悬扬所决定的。
另外,黄骅港和京唐港在夏季无风浪时不出现航道淤积现象也从反面证明了上述结论。
2.2 近岸水流的作用虽然波浪作用是航道淤积的主要诱因,但近岸水流运动往往对航道淤积分布起着十分重要的作用。
图1显示了我们利用2维ADCIRC潮流模型计算得到的无风情况下落潮过程中黄骅港流场情况,图2、3分别显示了8级NE向风作用下2维ADCIRC模型和SWAN模型耦合计算得到的综合考虑了风、浪(辐射应力)、潮影响后黄骅港落潮和京唐港涨潮过程的流场情况。
由图1可见,港口工程修建后,由于建筑物与水流的相互作用,黄骅港北侧形成了沿建筑物向外的水流运动,该水流运动使得中等风浪天气时浅水区(如-2 m等深线以内)由波浪掀起的泥沙向外运动输送到航道内,产生航道淤积。
由图2和图3可见,在风暴作用期间,受各种动力因素影响,粉沙质海岸港口建筑物附近出现明显的沿海岸建筑物流动的水流,可以简称为沿堤水流。
这种沿堤水流运动可以使近岸浅水区高浓度泥沙大量向深水区输送,并与航道相交,从而使航道局部位置产生比较强烈的淤积。
港口建筑物附近水流运动十分复杂,对不同海岸,各种动力因素所起的作用不尽相同。
例如,黄骅港附近海岸岸滩极为平缓,潮流与风吹流对港口建筑物附近的沿堤流起着决定性作用,而京唐港附近海岸岸滩坡度则较陡一些,潮流与波浪引起的沿岸流对港口建筑物绕流起着决定性作用。
从以上分析可以得知,对于粉沙质海岸的航道淤积,港口建筑物附近的水流运动对航道淤积起着十分重要的作用。
2.3 回淤现象的综合分析根据上述结论和近年来黄骅港、京唐港等粉沙质海岸的工程实践,我们有以下基本认识:在非常平缓的粉沙质海岸上,如黄骅港,在中等风浪天气下,港口也会发生一定的淤积。
由于港口口门位置在-2.5 m等深线处,该处在中等风浪天气下基本无泥沙悬扬,因此,造成航道淤积的泥沙主要是-2.0 m等深线以内受波流作用掀起的泥沙,由沿堤水流携带并在航道落淤而造成的。
对于风级较大且持续时间较长的大风暴过程,大浪作用使水深较大的区域(口门以外)就有大量泥沙悬扬,沿堤水流作用的相对重要性反而有所降低。
对于岸滩坡度稍陡一些的粉沙质海岸,如京唐港,由于口门水深较大,无论小或大风暴过程中,口门以外直接由波浪掀起的泥沙量都较小,航道的淤积均和沿堤水流有关。
从黄骅港与京唐港的淤积分布上也可以证实这一点,黄骅港在小或中等风暴过程作用下,淤积分布主要集中于口门以外8 km以内,而在大风暴作用下,则容易形成外航道的全线回淤;京唐港无论波浪作用大小,其淤积主要集中在口门附近。
综合以上分析结果可以认为,波浪作用是造成粉沙质海岸泥沙悬扬运动的主要因素,近岸水流作用,特别是沿堤水流对航道淤积起着十分重要的作用。
沙质海岸港口平面布置的讨论3.1 粉沙质海岸港口建设的平面布置型式根据上述粉沙质海岸的回淤成因分析,粉沙质海岸的港口平面布置方式应该遵循以下原则:(1)口门最好选择在一般波浪条件甚至中等风暴过程不能使泥沙产生大量悬扬的水深处,(2)港口平面布置应避免出现沿堤水流携带大量泥沙向外输送的现象。
因此,对于粉沙质海岸拟建港口,选用如图4、5所示的两种平面布置型式是较为合理的:图4为港口建在较深水域中的栈桥-岛堤方案;图5为栈桥与双堤环抱式布置方案。
第一种方案将码头建在水深较大(如-10 m以上)处,尽量避免航道开挖,因此从根本上避免了航道回淤问题,但由于粉沙质海岸坡度十分平缓,这种方案存在掩护性差、港口利用率较低,码头距岸线过远,一次性投资较大等缺点。
第二种方案则承继了单引堤加双堤环抱方案的优点[19],可将港口口门布置在中等风暴不能掀起大量泥沙的等深线处,但将单引堤改为透空式栈桥,避免近岸地区形成沿堤流向外输送泥沙所造成的航道淤积。
我们认为,第二种方案在很多情况下是一种值得推荐的方案。
图6 (a)、(b)图分别显示了黄骅海岸采用栈桥-双堤环抱式布置后在无风天和8级NE向风作用下的近岸流场。
(a)图、(b)图分别与图1、2相比较(对应流场相位分别相同)可知,栈桥-导堤式布置方案的沿堤水流运动现象明显减弱,因此,由沿堤水流输送泥沙所造成的淤积必然会减小。
需要指出的是,上述栈桥-双堤环抱式方案可以有效避免中等风浪造成的航道淤积;对于岸滩坡度较陡的粉沙质海岸,也可以基本解决大风暴造成的航道回淤问题;但对于岸坡十分平缓的粉沙质海岸,大风暴引起的航道非掩护段的淤积仍是难以避免的,因为这时口门外除了沿堤向外的泥沙输送外还有波浪本身的大量掀沙。
3.2 关于粉沙质海岸已建港口的整治对于未来粉沙质海岸的港口建设,考虑本文3.1中推荐的布置型式是合理的,但对于目前已经建成的粉沙质海岸港口,如果舍弃已建港口而采用上述推荐布置方案,则相当于港口重建,其经济效益比较显然是不合理的。
为了进一步减小港口回淤,在现有港口建筑物的基础上进行整治工程建设是更为合理的选择。
一般来说,延长防沙堤对于港口减淤起着决定性作用,防沙堤延长虽然不能解决沿堤流问题,但近岸泥沙在随沿堤流运动过程中会逐渐落淤,从而可以减小非掩护段航道淤积。
在延长防沙堤时有两个问题有待深入研究: (1)如何延长防沙堤,在延长防沙堤的同时是否需要建造以及建造何种辅助性建筑物(如横向挡沙堤),需要结合港口具体情况来确定; (2)根据目前所了解的粉沙质海岸泥沙运动特性,在防沙堤顶高程的选择上,潜堤或顶高程在平均水位附近的中水堤在降低防沙堤费用的同时,也可能取得可观的减淤效果,但这方面还需要更深入的研究,特别是大量现场观测来证实。
4 结语本文根据近年来国内对粉沙质海岸泥沙运动规律的研究、大量港口工程实践和流场数值模拟结果,分析了粉沙质海岸港口发生淤积的原因,指出了波浪掀沙是港口回淤的主要诱因,而近岸复杂水流运动,特别是沿堤水流运动携带泥沙在航道落淤对航道淤积起着重要作用。
针对粉沙质海岸港口淤积特点,提出了粉沙质海岸修建港口时的合理平面布置型式,即栈桥加双堤环抱的港口平面布置可能是粉沙质海岸修建港口的合理选择。
另外,也对粉沙质海岸已建港口的减淤措施进行了讨论,指出了延长防沙堤是港口整治的合理方案。
需要指出的是,本文所讨论的粉沙质海岸,主要是针对波浪作为主要动力掀沙而潮流作用不能使泥沙大量悬扬的粉沙质海岸而言的。
实际上,我国还存在一部分潮流动力作用很强的粉沙质海岸河口,如江苏如东海岸等,对这些海岸的港口平面布置,还需要进一步研究。
参考文献:[1] JTJ213-98,海港水文规范[S].[2]Liu Jiaju, hang Jingchao. The channel of muddy coast, sedimentation calculation method and its application [ J]. Wat er conservancy water research,1993, (4):301-320.[3] 罗肇森.河口航道开挖后的回淤计算[J].泥沙研究, 1987,(2): 13-20.The extraction powder quality, and the coast of port modeKeywords:powder; Lift the sand with the waves. Along the dike flow; Channel sedimentation; Port layout1 the introductionBack silting computing in the study of port and port layout, is generally the coast is divided into two categories, one kind is muddy coast, one kind is sandy coast, such as the \"guidelines for seaport hydrology\" in our country have had more clear rules [1]. Muddy coast port channel back silting main consideration fine sediment suspended sediment deposition, has been put forward quite a lot of calculation method and formula [2-4]. According to over the years, the research of muddy coast, the double dike surrounded muddy coast port construction layout scheme has become a widely accepted model, the port arrangement type can effectively reduce aggradations of the muddy coast port, tianjin xingang as typical examples [5]. For sandy coast, generally considered the main cause of the port channel siltation caused waves of coastal sediment, so in view of the main direction of river sediment intercept sediment from upstream single jetty or don't hinder the sediment pier - island off the coast dam type is decorated become main solutions to port sedimentation, Mauritania friendship port built in our country is a classic example of the [6]. In fact, according to the engineering practice in our country in recent years and with the deepening of the sediment movement characteristics research, the concept of silty sand quality, and the coast gradually get the attention of people.Liu Guju muddy coast and YuGuoHua will back silting formula is extended to the waterway silt coast [7], Zhang Qinghe etc, from the Angle of sediment hydraulic characteristics and migration characteristics of silt coast is defined [8], such as Cao Zude further definition of silt coast quality, sediment movement suspension and deposition analysis and calculation are studied, such as [9-11]. Other work combined with practical engineering of silt coast sediment motion is analyzed [12-13]. Look from the current study results, silt coast sediment particle size range of the basic can be defined in the d50 is about 0.03 ~ 0.12 mm. Silt coast is concern, is that qualitative silt coast port back silting has its particularity, sudden deposition is one of the more significant phenomenon. In recent years, with the development of economy, built on silty sand mass coast port has become more urgent requirements, some powder mass has built off the coast of Hong Kong, is planning to build or expand. But some existing port silt mass coast back silting especially sudden sedimentation phenomenon exist in different degrees, in silt coast port construction quality suspicious, what port arrangement type can effectively reduce silt coast port sedimentation, established port how to punish the most economic and effective, as engineering construction need answer. Although recent Luo Gang and Yang Xihong [14], Kong Lingshuang etc. [15], and Yang hua and wheat seeding [16] on silty sand coast port layout problems are discussed, but some problems still need further understanding, therefore, this articleon the analysis of the silt coast sediment movement and channel back silting cause, on the basis of the discussion on the mode of silt coast quality building, in order to silt coast port design and sedimentation reduction quality control measures to provide the necessary basis.2 silt coast port back silting cause analysisMost of the silt coast has the characteristics of beach is gentle, such as the coast near jingtang for typical silty sand coast, sediment particle size of about 0.08 mm, the slope beach around 1/400 ~ 1/700 [17]; Dongying port of sediment grain size in 0.1 mm or so, also for typical silty sand coast, along the slope around 1/1 ~ 3/1 000 000 [16]. Although oil drilling near coast from the overall characteristics of sediment and the amount of clay particles, belongs to muddy coast, but from the seabed surface sediment particle size (0.03 mm) and movement characteristics, should belong to [12] in silty sand silt coast, along the slope in 1/2 around 000. In the flat above the silt coast build ports, in order to avoid the near-shore sediment movement caused severe port channel siltation, chose the most ports from coast started to build a long double surrounded by dike or single quote dike to add double unbroken dike layout pattern. Although these ports have long groin, but looked from the engineering practice in recent years, outside the port channel may still happen serious sedimentation. We will from the following several aspects of silty sand coast back silting mechanism is analyzed.2.1 the wavesIn a considerable amount of silt coast, wave action constitutes the main reasons for back silting in the waterway. Jingtang appeared several times more severe back silting are associated with heavy weather process, such as in November 1992, a northeast to the weather process of sand dike head appear channel serious silting phenomenon, the maximum silting thickness is 3.2 m; In December 1993, by the strong wind processes outside the channel siltation, maximum silting thickness of 2.5 m (11, 18). In October 2003 for more than two days of strong storms process, makes the jingtang channel maximum silting stronger more than 4 m. For oil drilling back silting phenomenon in recent years, under the action of strong wave of surface sediment of suspended silt Yang sedimentation, constitute the main mode of oil drilling channel siltation [12], for example in February 2001 and October 2003 times of strong wind, which caused the oil drilling outside channel more severe siltation, every time a tempest process caused by the channel siltation volume are more than 2 million m3, sudden silt largest storm process even more than 6 million m3, maximum silting thickness more than 3.5 m. Can learn from the above phenomenon, powder quality, and the strong coastal silt or sudden sedimentation are caused by the wave and sediment of a suspension Yang. In addition, oil drilling and jingtang harbour in the summer not appear when no wind channel sedimentation phenomenon also proved this conclusion from the opposite side.2.2 the role of the nearshore currentsAlthough the wave action is the principal cause of channel sedimentation, but nearshore currents tend to channel siltation distribution plays a very important role. Figure 1 shows we use 2 d ADCIRC tidal current model calculated without wind oil drilling flow field in the process of ebb tide, figure 2, 3 respectively shows the magnitude 8 NE to 2 d ADCIRC model under the action of wind and the SWAN model coupling calculated considering the wind, wave radiation (stress), oil drilling ebb after tide impact, and jingtang flow field in the process of flood situation. From figure 1 shows, port engineering construction, due to interaction with the flow of the buildings, oil drilling on the north side formed along the building outward flow movement, shallow water when the water flow movement makes medium rough weather (such as 2 m isobath) outward by the waves of the sediment transport in the channel, the channel siltation.From figure 2 and figure 3 shows, in effect during the storm, influenced by all kinds of incentive factors, silt mass coast port structures appear along the coast near flowing water, can be referred to as the dam water flow. This can make the shallow waters high concentration sediment moving along the dike flow to deep water area in great quantities, and fellowship with the channel, so that the channel deposition in local position is strong.Port buildings near the water flow movement is complex, with different coast, the role of the various dynamic factors is not the same. Oil drilling near coast along, for example, is very gentle, tide and wind flow on port nearby buildings along the dike flow plays a decisive role, and jingtang near the coast along the slope is steep, tide and wave caused by coastal current flow around on the port structures play a decisive role. From the above analysis, for silt coast channel siltation, the flow in the vicinity of the port building movement plays a very important role to the channel siltation.2.3 back silting phenomenon of comprehensive analysisAccording to the above conclusions, and in recent years, oil drilling, jingtang silt coast engineering practice, we have the following basic understanding: in a very gentle silt coast, such as oil drilling, under medium rough weather, port will occur certain sedimentation. Due to the position at the entrance of the port at 2.5 m depth contour, the basic no sediment suspension in medium rough weather, therefore, the main sediment siltation in the waterway is within 2.0 m depth contour by the wave function of the sediment flow, the along the dike flow carry and falls in waterway silting. For longer big storm wind scale is larger and the duration of the process, the wave function to make deeper water area at the entrance of the () there is a lot of sediment suspension and along the dike flow function instead of the relative importance of reduced. For a little steep slope along the silt coast, such as jingtang, due to the water depth is larger, at the entrance of the process, whether small or big storm outside the entrance directly by the waves of the sediment loads are smaller, the channel siltation and along the dike flow. From the deposition distribution of oil drilling and jingtang can also confirmed this, oil drilling under the effect of small or medium storm process, the deposition distribution mainly concentrates on the outsideat the entrance of the 8 km, and under the action of a big storm, siltation of all is easy to form the outside; Jingtang regardless of the size of the wave action, the deposition mainly concentrated near the entrance. Comprehensive the above analysis results can be thought of, wave action is the main factors of coastal sediments suspended silt uplift movement, nearshore currents, especially on channel siltation along the dike flow plays a very important role.Sandy coast port layout of the discussion3.1 powder mass coastal port layout of the construction of the modelAccording to the silt coast back silting cause analysis, qualitative silt coast port layout should follow the following principles: (1) the best choice in general at the entrance of the wave conditions even moderate storm process cannot make produce a large number of suspended silt Yang water depths, (2) the port layout should avoid outward along the dike water carry a lot of sediment transport. So for silt coast land port, chooses as shown in figure 4, 5, two kinds of layout pattern is reasonable: figure 4 for the port construction in deep waters in the dam pier - island; Figure 5 surrounded by pier and double barrier type layout. The first scheme will dock built in deeper water (such as more than 10 m), try to avoid channel excavation, thus avoided channel back silting problem fundamentally, but because of the silt coast very gentle slope, this solution is cover port utilization rate is low, and the terminal from the coast too far, shortcomings and so on one-time investment is larger. The second scheme is inherited the single quote dike with dual advantages of dike surrounded scheme [19], can be in port layout at the entrance of the medium storm cannot bring about a large amount of sediment depth contour, but change the single quote dike to openwork pier, avoid inshore areas along the dike flow caused by the sediment transport channel siltation. We believe that the second scheme in many cases is a recommended plan. Figure 6 (a) and (b) the figure shows the respectively in huanghua coast after the pier - double dike surrounded type decorates breezeless and 8 NE nearshore flow field under the action of the wind. Figure (a) and (b), respectively, compared with figures 1, 2 (corresponding to the flow field were the same phase), the pier - jetty type layout along the dike flow phenomenon is significantly weakened, therefore, caused by along the dike flow transporting sediment deposition will decrease.It should be pointed out that the pier with double dike surrounded type scheme can effectively avoid the secondary waves caused by the channel deposition; For along slope steep silt coast, also can solve the basic channel back silting problems caused by the big storm; But for the bank slope is gentle silt coast, big storm caused by the passage not cover period of sedimentation is still difficult to avoid, because the mouth outside besides outward along the embankment of sediment transport and wave itselfa lot of lift.3.2 about silt mass has built off the coast of port regulationFor future silt coast port construction, consider the arrangement type are recommended in this article 3.1 is reasonable, but to have been built in silt coast port,if give up already built port and the scheme of the recommended layout is equivalent to port reconstruction, its economic benefit is obviously unreasonable. In order to further reduce the port back silting in the existing port on the basis of the engineering construction building is a more reasonable choice. Generally speaking, the extension of the groyne sedimentation reduction plays a decisive role for the port, groyne extended although cannot solve the problem of flow along the dike, but nearshore sediment along the dike flow movement in the process will gradually fall deposition, which can reduce the cover period of channel siltation. In the extension of the groyne are two problems to be further study: (1) how to extend the groyne, the extension of the groyne and whether you need to build and build what kind of supporting structures, such as horizontal block sand dike, need to be connected with specific circumstances to determine; (2) according to the current know silt coast sediment movement characteristics, on the choice of sediment control edterminationof elevationof, submerged jetty or near the average level of the elevation of water in the dam in reducing the costs of groin at the same time, also can achieve significant sedimentation reduction effect, but also need further research, especially a large number of field observation to confirm.4 conclusionBased on the sediment transport of silt coast quality in our country in recent years in the research, a large number of port engineering practice and flow field numerical simulation results, alluvial silt mass coast port are analyzed, the reason, pointed out the wave lift sand is the main reasons for back silting in the port, and nearshore complex water flow movement, especially along the dike flow carry falls in waterway silting plays an important role in channel siltation. For silt coast port sedimentation characteristics, puts forward the powder quality and the reasonable layout pattern built off the coast of port, the pier plus double dike surrounded the port layout may be built off the coast of silt mass of rational choice. In addition, also existing on silty sand coast port sedimentation reduction measures are discussed, pointed out the extension of the groyne is reasonable scheme of port regulation.It should be pointed out that, this paper discussed the silt coast, mainly for wave as a main engine lift sand and tide effect can't make a lot of silt suspension Yang powder in terms of quality, and the coast. In fact, in our country there is a part of the strong tide force silt coast estuarine, such as jiangsu, such as the east coast to the coastal port layout, further research is needed.References:JTJ213-98 [1], the seaport hydrology specification [S].[2] Liu Jiaju, The channel of muddy squadron, sedimentation calculation method and its application [J]. Water conservancy Water research, 1993, (4) : 301-320.[3] Luo Zhaosen. Siltation after excavation of estuary calculation [J]. Journal of sediment research, 1987, (2) : 13-20.。
