论文英文摘要范文

2024-06-02

论文英文摘要范文(精选6篇)

篇1:论文英文摘要范文

摘要

微博是当前最主要的社交媒体之一,它的推广产生了一种新的网络营销方式一微博营销。

企业借助微博平台可以开展一系列的营销活动,以实现其提升知名度,扩大品牌影响力的目的。

微博营销已逐渐成为众多企业不可或缺的营销方式之一。

然而,微博营销作为一种新兴的网络营销方式,它与传统营销方式之间存在重大区别,加之,微博营销效果的影响因素尚未准确界定,营销效果难以科学评价,因此,多数企业开展微博营销存在很大的盲目性,微博营销仍然处于摸索阶段。

微博营销究竟能为企业带来多大效益,这是企业最为关注的问题,然而,对于微博营销效果影响因素及效果评估的科学研宄,目前尚处于稀缺状态。

本文以酒店微博为研宄对象,对微博营销效果的影响因素及营销效果的评估进行深入研究:

在总结现有的关于微博营销的研究基础上,假定各酒店决策层对酒店开展微博营销持有相同的重视程度,主要从受众(微博用户)的角度探究酒店微博营销效果的影响因素。

进而,以AISAS模式为指导,剖析微博用户行为,通过问卷调查,并结合Excel和SPSS19.0数据统计分析,构建酒店微博营销效果的影响模型。

在此基础上,提出微博营销效果的评估指标假设模型,进而利用层次分析法构建完整的评估指标体系一以酒店微博营销综合效果为目标层,以影响力效果、传播效果和转化效果为准则层,

以微博影响力、品牌影响力、互动效果、粉丝价值、实际交易量和顾客满意度等8个指标为分准则层,以微博影响力指数、品牌热议度、品牌搜索数等14个指标为指标层。

最后,将此评估指标体系应用于宁波华侨豪生大酒店和宁波海尚大酒店,通过对酒店微博数据的观察和收集,运用综合指数法测算出酒店微博营销效果指数。

结果显示,这两家酒店微博营销效果收效甚微:

1.两家酒店并未充分利用微博展开各类营销活动,微博营销仍处于低水平,微博营销的开展并未使酒店的品牌知名度有明显的提升;

2.关于被转发数、被评论数和点赞数,两家酒店均不理想,粉丝中,认证粉丝比例较低,而活跃粉丝比例较为可观,但互动类活动组织很少,如何吸引大量粉丝关注,提升粉丝价值是两家酒店亟待解决的难题;

3.实际交易量并不乐观,虽然有较高的顾客满意度,但调查期内顾客发布消费体验的微博数却很少。

这两家酒店在一定程度上反映了目前酒店业开展微博营销存在的问题,由此,针对其营销现状,本文还提出了相关对策和建议:

1.准确定位,循序渐进;

2.把握微博发布的频率和最佳时间;

3.微博内容展现个性化;

4.线上线下营销活动巧妙结合;

5.增加有效粉丝,注重与粉丝互动。

关键词:微博营销;影响因素;效果评估;指标体系

ABSTRACT

Weibo is one of the most important social media tools nowadays, thepopularization of Weibo brings a new kind of network marketing - Weibomarketing. Enterprises use Weibo platform can carry out a series ofmarketing activities, in order to raise visibility and expand brand impact.

Weibo marketing has gradually become one of the indispensablemarketing channels of many companies. However, as a new kind ofnetwork marketing, Weibo marketing has some significant differencefrom traditional marketing.

In addition, the influence factors of Weibomarketing effectiveness has not been precisely defined, and marketingeffectiveness is difficult to scientific assessment. Therefore, the majorityof firms develop the Weibo marketing are blind,

and Weibo marketing isstill at the exploratory stage. How much benefit Weibo marketing canbring for enterprises, which is the enterprise most concern. However, thescientific studies about the influence factors and evaluation of Weibomarketing effect are in a state of scarcity.

This paper takes the hotels Weibo as the research object, and deeplystudies the influence factors and evaluation of the Weibo marketingeffect:

On the basis of summarizing those existing research on Weibomarketing, it is assumed that the decision-makers from different hotelshold tiie same degree of attention on Weibo marketing. Then,

this paperexplores the influence factors of hotels Weibo marketing effect from theWeibo users perspective, analyzes the Weibo users behavior guided byAISAS mode ,

tiirough the questionnaire survey to build the hotel Weibomarketing effect model with statistical software such as Excel and SPSS19.0.

On this basis, this paper puts forward tiie Weibo marketing effectevaluation index hypothetical model, and then use AHP to build acomplete evaluation system ,

this system takes the hotels Weibomarketing comprehensive effect as the goal layer, influence effect,communication effect and transformation effect as the criterion layer,takes Weibo influence, brand influence ,

interaction effect, fans value,actual trading volume and customer satisfaction as the sub-criterion layer,and takes 14 indexes such as Weibo influence index, brand hot degreesand brand search as the index layer.

Finally, this evaluation index system is applied to Ningbo HowardJohnson Plaza Hotel and Ningbo Riviera Hotel. Through the observationand data collection of the hotels Weibo, measure the hotel Weibomarketing effect index with the comprehensive index method.

The resultsshow that these two hotels have little effect about Weibo marketing:

1. Both hotels did not make full use of Weibo to launch various marketingactivities, Weibo marketing is still at a low level, and Weibo marketingdid not make the hotel brand awareness has obvious improvement;

2.Those hotels are not ideal about the number of transmission, commentand praise by Weibo users. Among their fans, the ratio of certified fans islow, while the ratio of active fans proportion is relatively substantial,

andfew interactive activities are organized. So, how to attract a large numberof fans, and enhance the fans value is an urgent problem;

3. The actualtrading volume is not optimistic. Although there is a higher satisfaction,customers release very few consumption experiences by Weibo during theinvestigation period.

To some extent, both hotels reflect the problemsexisting in the hotel industry to carry out the Weibo marketing, thus, fortheir marketing situation, this article also brings up some suggestions andcountermeasures:

1. Accurate positioning, step by step;

2. Grasp thefrequency and the best time on releasing information;

3. Showpersonalized content;

4. Online and offline marketing activities arecombined together;

5. Increase effective fans, pay attention to interactwith fans.

KEYWORDS: Weibo marketing; Influencing factors; Effect evaluation;Indicator system

篇2:论文英文摘要范文

随着科学技术的发展,为满足对外交流的需要,国家统一规定,公开发表的学术论文应附有英文摘要。

英文摘要的内容要求与中文摘要一样,包括目的、方法、结果和结论四部分。但是,英文有其自身特点,最主要的是中译英时往往造成所占篇幅较长,同样内容的一段文字,若用英文来描述,其占用的版面可能比中文多一倍。因此,撰写英文摘要更应注意简洁明了,力争用最短的篇幅提供最主要的信息。第一,对所掌握的资料进行精心筛选,不属于上述“四部分”的内容不必写入摘要。第二,对属于“四部分”的内容,也应适当取舍,做到简明扼要,不能包罗万象。比如“目的”,在多数标题中就已初步阐明,若无更深一层的目的,摘要完全不必重复叙述;再如“方法”,有些在国外可能早已成为常规的方法,在撰写英文摘要时就可仅写出方法名称,而不必一一描述其操作步骤。

中英文摘要的一致性主要是指内容方面的一致性,目前对这个问题的认识存在两个误区,一是认为两个摘要的内容“差不多就行”,因此在英文摘要中随意删去中文摘要的重点内容,或随意增补中文摘要所未提及的内容,这样很容易造成文摘重心转移,甚至偏离主题;二是认为英文摘要是中文摘要的硬性对译,对中文摘要中的每一个字都不敢遗漏,这往往使英文摘要用词累赘、重复,显得拖沓、冗长。英文摘要应严格、全面的表达中文摘要的内容,不能随意增删,但这并不意味着一个字也不能改动,具体撰写方式应遵循英文语法修辞规则,符合英文专业术语规范,并照顾到英文的表达习惯。

选择适当的时态和语态,是使摘要符合英文语法修辞规则的前提。通常情况下,摘要中谓语动词的时态和语态都不是通篇一律的,而应根据具体内容而有所变化,否则容易造成理解上的混乱。但这种变化又并非无章可循,其中存在着如下一些规律:

1、时态:大体可概括为以下几点。

1)叙述研究过程,多采用一般过去时。

2)在采用一般过去时叙述研究过程当中提及在此过程之前发生的事,宜采用过去完成时。

3)说明某课题现已取得的成果,宜采用现在完成时。

4)摘要开头表示本文所“报告”或“描述”的内容,以及摘要结尾表示作者所“认为”的观点和“建议”的做法时,可采用一般现在时。

2、语态:在多数情况下可采用被动语态。但在某些情况下,特别是表达作者或有关专家的观点时,又常用主动语态,其优点是鲜明有力。

掌握一定的遣词造句技巧的目的是便于简单、准确的表达作者的观点,减少读者的误解。

1、用词力求简单,在表达同样意思时,尽量用短词代替长词,以常用词代替生僻词。但是当描述方法、步骤时,应该用狭义词代替广义词。例如,英文中有不少动词,do,run,get,take等,虽简单常用,但其意义少则十几个,多则几十个,用这类词来描述研究过程,读者难免产生误解,甚至会不知所云,这就要求根据具体情况,选择意义相对明确的词,诸如perform,achieve等,以便于读者理解。

2、造句

1)熟悉英文摘要的常用句型:尽管英文的句型种类繁多,丰富多彩,但摘要的常用句型却很有限,而且形成了一定的规律,大体可归纳为

a)表示研究目的,常用在摘要之首In order to……This paper describes…, …The purpose of this study is……

b)表示研究的对象与方法The [curative effect/sensitivity/function] of certain [drug/kit/organ….] was [observed/detected/studied…]

c)表示研究的结果:[The result showed/It proved/The authors found] that……

d)表示结论、观点或建议:The authors [suggest/conclude/consider] that…

2)尽量采用-ing 分词和-ed 分词作定语,少用关系代词 which , who 等引导的定语从句。由于摘要的时态多采用一般过去时,使用关系代词引导的定语从句不但会使句式变的复杂,而且容易造成时态混乱(因为定语和它所修饰的主语、宾语之间有时存在一定的“时间差”,而过去完成时、过去将来时等往往难以准确判定)。采用-ing 分词和-ed 分词作定语,在简化语句的同时,还可以减少时态判定的失误。

篇3:论文英文摘要范文

下面两篇摘要第一篇是摘自国外学者写的, 第二篇是摘自一名国内在校博士写的。通过对这两篇摘要进行对比分析研究, 让我们更加明确的了解英文摘要的写作规范。

1 (Written in original English) This paper describes a new“modified pulse arc evaporation process”which represents a combination of both d.c.And pulse cathodic arcs.The aim is to give a comparative overall view.The paper reports on measurements of spot movement on the target, arc voltage response and ion current under different electric conditions, such as current magnitude, current changing rate and pulse duration.There are possibilities to improve the target consumption;to reduce the upper stability limit;and to increase the spot velocity, the bias current density in the pulse phase and the plasma power.For optical measurements of spot movement a new high-speed video camera was used.

2 (Written by Chinese student in English) Every machining technique leads to distinguishing surface feature and precision characteristic.The non-traditional finish machining can improve the surface quality and precision of parts.The improvement of these can advance the performance and life of parts.The non-traditional machining has its superiority.

英文摘要大体上包括四个部分:研究目的、方法、结果、结论。研究目的主要说明作者写此文章的目的或主要解决的问题, 表明研究的范围和重要性;研究的方法主要是提出解决问题的方法以及主要工作过程;研究的结果则是作者在此研究过程最后得到的结果;结论是说明该研究结果的实际应用价值。

文章的研究目的必须在英文摘要中体现出来。从摘要1中“This paper describes a new“modified pulse arc evaporation process”which represents a combination of both d.c.And pulse cathodic arcs.The aim is to give a comparative overall view.”我们可以明显看到该文章的研究目的。鲜明的文章目的能够让读者一目了然的了解到这篇文章所要论述的内容, 但是在实际写作中, 有很多学者在整篇摘要里面都是一些一般性的论述, 说来说去, 最后让别人读了一半天, 也不知道这篇文章是要解决什么问题。第二篇摘要从前到后都是在陈述光整加工技术, 让人很迷惑, 不知道这篇文章重点是要论述那一方面的内容。一篇没有目的性的文章自然也就没有可读性。

研究的方法也应该在英文摘要中体现出来, 这一点是很多中国学者很容易忽视的。从上面两篇摘要对比就可以发现:第一篇中的“measures”就告诉了读者本文作者是要通过什么方法来解决所提出的问题;而在第二篇, 不但没有像“measure”, “method”等表达方法的词, 而且从根本上忽视了这一点。解决的方法应该是一篇文章的核心, 没有作者自己的解决思路的摘要, 从某种意义上说, 这是一篇很失败的文章摘要, 那么这篇文章也不可能是一篇好文章。

研究的结果作为摘要中一部分也是不可少的, 也是作者所采用的解决方法是否合理的一个重要依据。没有研究的结果, 就是你选择的方法再好, 也只是在纸上谈兵, 侃侃而论, 没有自己的立论点。在第一篇中, 我们可以从“There are possibilities to improve the target consumption;to reduce the upper stability limit;and to increase the spot velocity, the bias current density in the pulse phase and the plasma power.”中了解到作者可能得到的结果。而在第二篇中, 结果不是很明显。

研究的结论这一部分往往在研究的结果中体现出来, 所以在一部分你可以结合研究的结果做出自己的见解。有时候作者可以根据目前的实验结果为了对以后的进一步工作的开展给出自己的结论。

最后, 在语言表达上也是很重要的一个方面。很多中国学者自己也清楚, 一看人家外国学者写的英文摘要就是感觉很舒畅, 而且句式结构多样, 上下连接紧凑。但是一旦让自己写文章, 就开始感觉自己的写的不地道, 语句形式单一, 给人一种感觉就是在勉强的中文英文之间互译。从第二篇英文摘要上我们就有这种体会, 在摘要中几乎所有的语句采用主、谓、宾中国式英语结构, 句式千篇一律, 而且语句之间没有任何的连接, 互相独立。其实, 在英文摘要语言表达中, 只要你稍微留心注意许多国外优秀的英文摘要, 就可以很好的完成。比如在目的中你可以采用“The purpose of this paper is……”句型;在方法中可以采用“The method used in our study is know……”;在结论中我们可以采用“In conclusion, we state that……”, 这样下来既地道又相互连贯, 而且层次分明, 何乐而不为?

另外还需要注意一些的就是英语语法方面。比如在时态上, 英文摘要中习惯于一般现在时, 能够突出文章内容的即时性和客观性。但也有时候为了便于说明论题发展背景而用过去时或现在完成时。在人称上, 只能用第三人称, 不能用第一人、第二人称如我、我们等。还有在标点、大小写、缩写等方面也需要留心注意。

从上面对比分析, 我们可以看到, 只要我们认真领会写作规范, 注意英语的语言表达特点, 并积累一些常用的典型例句, 完成一篇好的英文摘要其实很简单的。

摘要:英文摘要是一篇好的学术文章不可缺少的部分, 也是SCI、ISTP和EI等索引工具收录的依据。因此, 我国学者和研究生应该掌握好英文摘要写作要点。本文通过对两篇分别来自英国和中国学者所写的英文摘要的对比分析研究, 得出结论:一篇成功的英文摘要关键在于有正确的指导思想和方法。如果在写作的时候做到目的明确, 结构合理, 语言表达流畅, 完成一篇质量比较高的英文摘要不是望尘莫及的。

关键词:英文摘要,写作规范,语言表达

参考文献

[1]朱建祥.科技论文摘要翻译探讨[J].商丘师范学院学报, 2003, 8, 19 (4) .

篇4:本期论文英文摘要

Abstract:Whether the bank operates well depends on the public confidence, i.e. the bank credit worthiness. In-creasing bank capital adequacy and maintaining the stable bank income inflow, the steady support and guaranteed quality,etc. are the means to raise and maintain the bank credit worthiness. In our country the bank capital adequacy has not yetbeen up to the international standards; the credit asset quality is low; the profit is yearly decreased, and the state creditworthiness guarantee has become the key factor of prudently operating the state bank. Posterior to the accession to WTO,with the opening up of banking businesses, the role of the state credit worthiness guarantee has been weakening and itswithdrawal is faced with a series of difficulties.

Key Words: guaranteed state credit worthiness; state bank; capital fund; guaranteed deposit system

篇5:中英文摘要

作者姓名:段小洁

论文题目:单壁碳纳米管的AFM操纵、形变及相关拉曼光谱研究

作者简介:段小洁,女,1980年2月出生,2002年9月师从于北京大学刘忠范教授,于2007年7月获博士学位。

中文摘要

对形变碳纳米管(CNTs)的研究,包括研究其在应力存在下的结构演化、应力对其各种光电性质及电子能带结构的影响等,不仅对CNTs在复合材料、纳电子和纳机电器件、以及应力传感器等中的应用具有重要意义,还对相关理论的发展有巨大推动作用。本论文发展了对表面上单壁碳纳米管(SWNTs)的原子力显微术(AFM)可控操纵方法,基于此AFM可控操纵,研究了CNTs在弯曲形变下的屈曲行为,以及SWNTs在扭转和拉伸两种形变下的共振Raman光谱特征。主要成果包括:

1.发展了对表面上SWNT的AFM可控操纵方法;

通过对操纵过程中针尖运动路径的合理设置、SWNT上操纵位置和针尖下压距离的选择,可以向SWNT中引入各种类型的应力。SWNT中产生的应力由其和基底间的相互作用力保持。发展了基于Si的AFM氧化的SWNT纳米焊接术,以增加AFM操纵的可控性。当对表面有SWNT的基底Si进行AFM氧化时,新生成的SiOx会对SWNT进行包覆,从而可以将SWNT在氧化点有

效的固定到基底表面。而且SWNT的存在会对Si基底的AFM氧化有明显的增强作用,相同条件下,表面有SWNT的Si氧化后产生的SiOx,比没有SWNT时更多,这种增强作用有利于对

SWNT的焊接固定。焊接的强度可以通过改变氧化偏压、针尖运动速率(氧化时间)等进行调节,提高氧化偏压、降低针尖移动速率有利于增强纳米焊接的强度。空气中热氧化实验和拉曼光谱的表征均证明,此焊接过程对SWNT的化学结构无明显影响。在某些点对SWNT进行焊接固定后,AFM操纵引入的形变的大小和分布可以被有效地控制,从而大大增加AFM操纵的可控性。

采用更强的AFM氧化条件,可以实现SWNT和Si的同时氧化,从而可以在任意位点对SWNT进行切割。结合AFM纳米切割、焊接和操纵等操作,可以构筑各种复杂形状的SWNTs,体现

了AFM作为纳米工具箱的作用。

2.研究了CNTs在弯曲形变下的屈曲行为;

通过选择合适的操纵位点、被操纵的CNT片段长度、操纵路径并优化针尖下压距离,可以严格控制弯曲CNT的角度,这样通过AFM操纵对同一CNT的可控弯曲,获得了一系列弯曲角度逐渐增大的CNT。CNT被操纵以后,与基底相互作用力会有明显减小,这使得CNT的有效弯曲区域,位于与基底只有vdW相互作用的被操纵部分,在AFM表征下表现为固定部分和被操纵部分的交点。有效弯曲部分与基底间仅有vdW相互作用,其长度在整个弯曲过程中几乎保持不变。

通过记录弯曲“点”在弯曲角度逐渐增大过程中的高度变化,研究了CNTs在弯曲形变下的结构演化和屈曲行为。发现不同CNTs在弯曲过程中,表现出“突变”和“渐变”两种屈曲模式,分别对应于弯曲“点”高度的突跃、均匀弯曲向屈曲结构的直接转化,和弯曲“点”高度的逐渐增大、均匀弯曲向屈曲结构的逐渐转化。“渐变”屈曲导致一系列屈曲过渡态的出现。“突变”多发生于小直径管,而“渐变”更常见于大直径管。通过对CNTs的层数和厚度等的估算,发现一般情况下,“渐变”屈曲模式的CNTs比“突变”模式的CNTs具有更大的厚度直径比。对“突变”屈曲模式的CNTs,临界屈曲角度随CNTs直径的增大而减小。

分子动力学模拟发现,(1)所研究的CNTs中,SWNTs均为“突变”屈曲模式,而双壁和三壁管均采取“渐变”屈曲模式;(2)“渐变”屈曲过程对应弯曲角度逐渐增大时,多壁管从最外层到最内层的逐渐屈曲,和各管层屈曲程度的逐渐增加,这是由其多层结构导致的各层壁屈曲行为的不同步,和管壁间vdW相互作用对屈曲的阻碍造成的,这说明MWNTs的多层结构是导致其“渐变”屈曲的主要原因;(3)基底的vdW相互作用对CNTs的屈曲行为没有明显影响。从导致两种屈曲模式的机理考虑,除直径外,CNTs的层数对其屈曲行为也有重要影响,这预示了在CNTs的力学性质中,存在不同于传统尺寸效应的双尺寸效应,即直径和层数共同决定CNTs力学行为。

本工作利用AFM可控操纵,在实验上几乎全程观察了CNTs在弯曲过程中的结构演化和屈曲形成过程,其所揭示的两种屈曲模式的形成规律,不仅对大量存在的CNTs形变的理论工作提供了支持和参考,一定程度上填补了实验上的空白,还对CNTs在复合材料、纳电子和纳机电器件、以及应力传感器等中的应用具有重要意义,3.研究了扭转和拉伸形变下单根SWNTs的共振Raman光谱行为;

AFM操纵可以向超长SWNT中同时引入扭转和拉伸应力,由于拉伸形变比扭转形变的传输距离更远,在操纵点附近扭转和拉伸两种形变同时存在,距离操纵点较远的区域,只有纯拉

伸形变存在。扭转形变的产生证明了SWNT在AFM操纵下滚动的发生。

扭转和拉伸形变都会导致SWNTs拉曼模振动频率的变化。研究发现:(1)扭转形变下,RBM变大,位于~1600 cm-1的G+(E2(g))模振动频率发生较大的红移,而其他在1590 cm-1~1560

cm-1范围内的大部分G模会发生轻微的蓝移,振动频率发生红移的G模的位移量,一般远远大于发生蓝移的G模的位移量;(2)拉伸形变下,RBM和G+(E2(g))模振动频率不变,而在1590 cm-1~

1560 cm-1范围内的大部分G模会发生明显的红移。(3)不同Raman活性模对形变的敏感度不同,扭转形变下,RBM、位于~1600 cm-1的G+(E2(g))模比其他G模更敏感,而在拉伸形变下,其他G模却具有更高的敏感度。这与形变导致的发生变化的C-C键是否与各模的原子位移模式相关联有关;(4)通过对SWNTs中形变量大小和Raman频率对形变变化率d/d地计算,发现RBM振动频率对扭转形变的变化率d(RBM)/dt,随SWNTs手性角的增大几乎线性增大。

某些SWNTs中,扭转形变导致的对称性破缺还会导致Raman模的分裂或新模的出现。按照预测,这种分裂或新模的出现最可能发生在锯齿形和椅形SWNTs中。扭转和拉伸形变都会导致SWNTs共振拉曼振动模强度的变化,这体现了形变对SWNTs电子跃迁能Eii的影响。根据

共振拉曼理论和RBM峰的IAS/IS,可以计算扭转和拉伸形变对Eii影响的方向和大小。

应力对SWNTs共振Raman光谱的影响一直是人们关注的重要问题,本工作首次在实验上研究了扭转形变下SWNTs共振Raman振动频率和强度的变化。利用AFM操纵在单根SWNTs水平上的研究,可以排除不同直径和手性带来的平均效应,从而有利于揭示SWNTs的本征性质。对拉伸和扭转形变在同根SWNT中的比较,也为理解不同应力对SWNTs拉曼影响的不同提供了有利条件。

4.AFM操纵引入的应力沿SWNT管轴分布的分析和调控,及SWNTs相关力学性质的比较;分析了超长SWNT中,AFM操纵引入的应力的传输和分布,由于SWNT与基底间摩擦力的存在和AFM操纵后应力的部分驰豫,扭转和拉伸应力沿SWNT管轴都呈“”形分布,应力分布的各特征量,如应力的最远传输距离、最大应力点的位置和最大应力值、应力线性分布的斜率等,决定于AFM针尖施加到SWNT的力的大小、SWNT的剪切模量或弹性模量、以及SWNT与基底间摩擦力的大小;通过控制AFM操纵和采用图案化基底,对SWNT中应力的大小及分布进行了调控;通过比较不同SWNTs的应力分布特征量,在单根SWNT水平上,研究比较了它们的各力学参量,如剪切模量、杨氏模量,以及与基底间摩擦力的相对大小。各力学参量对SWNTs的直径无单调关系,说明了SWNTs手性对力学性质的影响。

关键词:单壁碳纳米管,AFM操纵与加工,形变,屈曲,共振拉曼光谱

AFM Manipulation, Deformation and Related Raman Spectroscopy of

Single-Wall Carbon Nanotubes

Duan Xiaojie

ABSTRACT

The study on deformed carbon nanotubes(CNTs), including the study of their structure evolution and properties change under strain, is important not only for the application of CNTs in composite materials, strain sensors, nanoelectronic and nanoelectromechanical devices, but also for the development of related theory.In this thesis, we have developed controlled atomic force microscopy(AFM)manipulation techniques for single-wall carbon nanotubes(SWNTs)on surfaces.Using this controlled AFM manipulation, the buckling behavior of CNTs under bending, and resonance Raman spectroscopy of SWNTs under torsional and uniaxial strains, have been studied.The main results are listed as followings:

1.Controlled AFM manipulation techniques for SWNTs on surfaces have been developed By defining proper tip path, manipulation position on SWNT, and choosing optimal tip pressing distance, different kinds of deformation can be induced into SWNT.The deformation is stabilized by the interaction between SWNTs and substrate.To get controlled AFM manipulation, a new kind of nanofabrication---nano-welding has been invented based on the AFM oxidation of Si substrate.When the Si substrate with SWNT on top of it is oxidized by the AFM tip, the newly formed SiOx will grow around the tube, effectively fixing that site of SWNT onto the Si substrate.The existence of SWNT can enhance the oxidation of Si.With same oxidation condition, more SiOx can be produced with the presence of SWNT than the case where there is no SWNT.This is helpful for the fixing.The intensity of the welding can be modulated by changing the oxidation voltage and the tip moving speed.With higher voltage and slower tip moving, stronger welding can be obtained.From the thermal oxidation of SWNTs in air and the Raman characterization, it was found that this nano-welding has no obvious influence on the chemical structure of SWNTs.Together with this nano-welding, the magnitude and distribution of strain induced into SWNT by AFM manipulation can be well controlled.Both SWNT and Si can be oxidized when using stronger oxidation condition(much higher voltage and lower tip moving speed), thus the SWNT can be cut at well defined position.Combining this AFM cutting, nano-welding and manipulation, complex SWNT-based structures can be constructed, proved the function of AFM as a nano-toolbox.2.The buckling behavior of CNTs under bending has been studied

By choosing proper manipulation site on SWNT, the length of the fragment which is being manipulated, manipulation path, and optimal tip pressing distance, the angle can be well controlled when SWNT is bent by AFM manipulation.Based on this controlled bent of CNT by AFM manipulation, A CNT with a series of different bending angles has been obtained.The interaction between manipulated SWNT fragment and substrate is largely decreased after the manipulation.And the effective bending region is located at the fragment where Only vdW interaction exists between it and the substrate.It appears as the cross point between the fixed SWNT part and

manipulated SWNT part in the AFM image.Only vdW force exists between the effective bending region and substrate, and its length keeps constant when changing the bending angle.Through recording the height change at the effective bending region when changing the bending angle gradually, The structural evolution and buckling behavior has been investigated under the bending.Two distinct „abrupt‟ and „gradual‟ buckling modes have been revealed in different CNTs.For the „abrupt‟ buckling mode, the height of the bending „point‟ has a sudden increase, and an abrupt transition from the uniform bending to buckling happens.While the „gradual‟ mode corresponds to a gradual increase of the height at the bending „point‟, with a gradual transition from uniform bending to buckling.The „gradual‟ buckling results in a series of buckling intermediate formation.„Abrupt‟ buckling mode is mostly found for small diameter CNTs, while for large diameter CNTs, the „gradual‟ mode is more common.Through the estimation of the wall numbers and thickness of CNTs, it was found that the CNTs with „abrupt‟ buckling mode has smaller thickness diameter ratio than the CNTs with „gradual‟ buckling mode.The critical buckling angle decreases with the increase of CNT diameter for the „abrupt‟ buckling mode.The buckling behavior has also been investigated by molecular dynamics(MD)simulations.It was found:(1)for all the CNTs studied, the SWNTs have “abrupt” buckling mode, and double and three walled CNTs take “gradual” buckling modes;(2)the “gradual” buckling corresponded to the process that different tube walls of MWNTs buckled at different bending stages, and the buckling degree of individual tube walls gradually increased along with the bending strain increase.This is caused by the unsynchronization of the buckling for different walls caused by the multi-shell character, and the retarding of buckling by the inter-wall vdW force.The study on the formation of the two buckling modes found that the multi-shell structure of MWNTs accounts for the “gradual” buckling modes;(3)The MD studies also proved that the vdW interaction with substrate has no remarkable effect on CNTs buckling behavior.The study on the buckling mechanism suggests that except for the diameter, the wall number also determines the buckling behavior.This means for the mechanical properties of CNTs, a special “dual-size” effect may exists, that is, both the size and the thickness determine the CNTs mechanical behavior.By using controlled AFM manipulation, the work here observed the structural evolution and buckling formation almost in the whole bending process.The founding about the two buckling modes, not only provides support and reference for the relevant theoretical study, fills the gap between theory and experiment, but also is important for the application of CNTs in composite materials, nanoelectronics and NEMs, and strain sensors.3.The resonance Raman spectroscopy of individual SWNTs under torsional and uniaxial

strain has been investigated

The AFM manipulation can induce both torsional and uniaxial strains into the ultra-long straight SWNTs.Because the longer propagation distance of uniaxial strain than the torsional strain, only pure uniaxial strain exists at region far from the manipulation point.While at region close to the manipulation sites, both the two strains happen.The formation of torsional strain suggested the rolling of SWNT under the present AFM manipulation.Both uniaxial and torsional strain can change the Raman vibrational frequency.It was found that:

(1)the RBM and G-band spectra responded differently to the two types of strains.Under torsional strain, RBM frequency RBM was found to upshift and one of the modes assigned to E2 symmetry in the G+ band, which occurs at ~1600 cm-1(G+(E2(g))), downshifted significantly, whereas the rest G

modes located in the range of 1590 cm-1~1560 cm-1 are slightly upshifted.The redshift of the(G+(E2(g)), ismuch larger that the buleshift of other G modes;(2)Under uniaxial strain, RBM and G+(E2(g))do not have noticeable response and the rest of the G modes in the range of 1590 cm-1~1560 cm-1 are downshifted.(3)Different Raman modes have different sensitivity to both strains.RBM and G+(E2(g))is more sensitive to torsion than other G modes.Whereas under uniaxial strain, other G modes have larger sensitivity than RBM and G+(E2(g)).This is related to the correlation between the C-C bond change and the atom vibrational displacement of different modes;(4)The

calculation on the strain magnitude and frequency shift of Raman modes per strains d/d found that, under torsional strain, d(RBM)/dt nearly linearly increased along with the increase of the tube chirality angle.G-band was found to split into multiple sub-bands in some cases, presumably due to broken symmetry induced by torsion.This splitting is most likely found in zig-zag and armchair SWNTs.Both the uniaxial and torsional strains can change the intensity of resonant Raman peaks.This is originated from the influence of strains on electronic tranision energy Eii.From this change, the

modulation direction and magnitude of strains on the electronic transition energy of SWNTs can be calculated.The influence of strain on the resonant Raman spectra of SWNTs has drawn much attention recently.The work here firstly experimentally studied the torsional strain effect on resonant Raman spectra of SWNTs.And the study in the single SWNT scale by AFM manipulation can exclude the average effect originated from different diameter and chiraligy.This helps to reveal the intrinsic property of SWNts.The comparison of uniaxial and torsional strain for same SWNT, also benefit the understanding of the influence of different strains on SWNTs.4.The analysis and modulation of strain distribution along SWNTs axis, and the comparison

of related mechanical parameters of different SWNTs

篇6:英文摘要写作

论文的结构

Title(题目)、Author and working unit(作者及工作单位)、Abstract(摘要)、Keywords(关键词)、Introduction(引言)、Text(正文)、Conclusions(结果及结论)、Acknowledgements(致谢)和References(参考文献)等部分。

一、摘要的概念

 摘要又称概要、内容提要。放在标题页的正文之前,用不同于正文的字体排版,以突出其显著位置。

 摘要是以提供文献内容梗概为目的,不加评论和补充解释,简明、确切地记述文献重要内容的短文。

二、摘要的类型(Type of abstract)

 信息性摘要(报道性摘要、资料性摘要)(Information Abstracts)

A design of---was proposed for ;Our---model employed is  指示性摘要(说明性摘要、叙述型摘要)(Descriptive / Indicated Abstracts)

This article discusses---; It suggests;

Calculations were carried out---;The results of calculation show that。

 资料性摘要概括地阐述论文或报告中的主要结论,重点突出文中提及的新发现或有别于其他同类研究的结论。

结合型摘要(Informative Indicative Abstracts)

 此类摘要综合了说明性摘要和资料性摘要的特点

Abstract:(1)This paper discusses the effect of processing temperature on the room temperature resistivity and PTC characteristic of the PS matrix Sn-Pb alloy composite.(2)The results show that … and the low melting point of Sn-Pb alloy results in the excellent PTC characteristic.结构性摘要

 这类摘要先用断语归纳要点,再用句子加以简明扼要的说明。

 它便于作者模仿和套用,能规范具体地将内容表达出来,使审稿便捷,同时便于读者一目了然地了解论文所表达的各项内容和结论,用于计算机检索更是快捷高效。

 资料性摘要与说明性摘要相比,内容更详实,结构更完整,适用于课题报告、科研论文,也更多地被理工科类的大型摘要期刊采纳。

期刊论文摘要

*目的:使读者能迅速、准确地识别论文的关键信息,以便以电子文本的形式输入数据库或在网上发布。*基本要求:

a、有关方法、程序的描述应该简约,除非是专门介绍方法的论文。b、不宜用引语、图表。

c、避免使用非标准缩略语,但学术刊物自己规定使用的缩略语可用在题目和摘要中。d、绝大多数刊物都要求摘要是一个完整的段落。e、长度应根据刊物的具体要求而定。学位论文摘要

学士学位论文应使读者感到作者懂得科学的研究、分析方法,论文所述的目标明确、有价值; 硕士学位论文应使人感到有系统性、学术性、功底深厚;

博士学位论文应使评委感到有创新性或独立见解,有很强的系统性和学术性。

会议论文摘要

基本要求

a、很多会议对摘要格式有统一要求,有的甚至有表格。如果是这样,应该严格按照会议要求撰写摘要。

b、如果会议没有要求,100单词左右的短摘要可以不要小标题,较长的摘要最好加上标题,以便会议组织者审阅。长度通常以800至1200单词为宜。

c、摘要应该是信息性的,而不是描述性的。

d、只用一至二个图表。尽量不用引语,以免本来就有限的篇幅更紧张。不用非规范的缩略语。e、注意完整性,即有头、主体、有尾,逻辑严整。

会议论文摘要

大多数会议都要求提交“直接付印版”(camera-ready copy)式的摘要,要求摘要的格式一致。

“投稿要求”(Instructions to authors)中往往对字型、字号、页面四边空白的宽度、甚至用于编写论文的软件都有严格规定,打印时须留意。不管自己设计的格式、字型、字号等是否会更好,一定要遵守“投稿要求”中的规定。

概要

 需要向上级或主管人员汇报,或希望得到批准,得到经费资助的项目通常都有这种摘要。

三、如何写摘要

(一)摘要的内容

 对象——是论文研究、研制、调查等所涉及的具体的主题范围,体现论文的研究内容、要解决的主要问题,是问题的提出,研究方向的确立与目标的定位。

 方法——是论文对研究对象进行研究的过程中所运用的原理、理论、条件、材料、工艺、结构、手段、程序,是完成研究对象的必要手段。

三、如何写摘要

 结果——是作者运用研究方法对研究对象进行实验、研究所得到的结果、效果、数据,被确定的关系等,是进行科研所得的成果。

 结论——是作者对结果的分析、研究、比较、评价、应用、提出的问题等,是结果的总结,显示研究结果的可靠性、实用性、创新性,体现论文研究的价值与学术水平,是决定论文被检索的窗口。

Study of an efficient simulation method

Object.To propose a simple and efficient simulation method.Design.Hash-RM algorithm is compared to the all-associative algorithm.Main results.The Hash-RM algorithm facilitates simulation by reducing the average search depth and using the right-match comparion.Conclusion.For instruction traces, the present algorithm is not making great progress.For data traces, the Hash-RM algorithm is much faster than the all-associative algorithm.Key words.Hash-RM algorithm, all-associative algorithm, simulation.(二)摘要的语言

1、摘要的时态

(1)叙述研究方法和目的时,使用现在时态  例:This article sets out four of the main misconceptions, discusses why they have arisen, and why they can be so described. 译:本文对主要误解中的四种进行解释,探讨它们产生的原因以及为什么人们如此对它们进行描述。

(2)报道研究结果时,采用现在时态

  例:A method for stiffness calculation under vertical load is derived.译:推导出一种在垂直负载条件下计算硬度的方法。

(3)介绍研究过程时,可以用过去时态

 例:At the incident pump power of 22 W, the output power of 13.22 W was obtained, resulting in an optical conversion efficiency of 60.1%, while the slope efficiency was determined to be 64.8%. 译:当入射泵功率为22瓦时,可以获得13.22瓦的输出功率,从而达到60.1%的光学转换率;同时倾斜率达到64.8%。

(4)陈述结论,提出建议或是描述一般规律时,用现在时态

       例:In doing this, the article attempts to define some important characteristics of communicative language teaching as it is practiced at present.译:借此,本文力图对当前使用的交际语言教学法的一些重要特征给出相关的定义。

2、句型和表达方法 回顾某领域已取得的研究结果或介绍相关知识 阐明论文写作和研究目的 阐述论文的论点和作者观点 介绍研究过程和研究范围 介绍计算、测量          阐明论证

说明试验过程 介绍应用、用途 展示研究结果 介绍结论 进行评述 推荐和建议

提出进一步研究的可能性 突出论文的重点

回顾某领域已取得的研究结果或介绍相关知识

 例1:This paper reviews the method for dealing with…  译:这篇论文概述了处理……的方法。 例2:This article summarizes the theory on …  译:本文综述了关于……的理论。

 此类表达常用的动词有:present, summarize, review, outline等,用于资料性摘要的第一部分,文献回顾或背景介绍。

阐明论文写作和研究目的

例1:The purpose of the study is to explore new methods … 译:此项研究的目的是探索……的新方法。

例2:The paper attempts to define … in terms of … 译:本文尝试从……角度来定义。

例3:The study is aimed at finding out the basic similarities between… 译:本研究旨在找出……与……之间的基本相似点。

阐明论文写作和研究目的

例4:The main objective of the work is to justify … 译:此项研究的主要目的是论证……。例5:The primary goal of this research is … 译:这项研究的主要目标是……

例6:The main objective of our investigation has been to obtain some knowledge of … 译:我们调查的主要目的是获得……的一些知识。

阐明论文写作和研究目的

例7:Based on recent research, the author intends to outline the framework of … 译:作者通过近期的研究,旨在总结出……的基本结构。

例8:The authors are now initiating some experimental investigations to establish… 译:作者正进行一些试验性研究以建立……

阐明论文写作和研究目的

此类表达主要用于说明课题研究的目的和发表论文所期望达到的目标。

常用的名词有:purpose, aim, objective, goal;动词有:aim, attempt to, initiate, intend to, seek等,另外还可以用动词不定式充当句中的表语或者用目的状语来表达。

展示研究结果

介绍研究结果可以使用动词result, cause, increase, lessen等,词组 as a result, result in, arrive at,或使用这些动词相应的名词。

作者应根据自己的研究结果选择适当的词语准确地向读者作出报道。因此,此类表达没有特定地语句。

介绍结论

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