摘 要,位于正文之前的一段概括性的文字。高度地概括了正文中叙述的内容，突出正文的重点，是正文实质性内容的介绍。摘要不是正文的一部分，但又不能脱离正文而单独印行。这一部分要有高度的概括性和简明性，可以说是科技写作中最为困难的部分。,1. 文摘的分类,科技文摘的体裁通常分为四种：陈述性文摘(Descriptive Abstract)资料性文摘(Informative Abstract)混合性文摘(Descriptive and Informative Abstract)评论性文摘(Critical Abstract) 陈述性、资料性、混合性文摘用以客观地介绍论文的内容，可根据具体情况选择一种。评论性文摘用于介绍对某项进展所作的评论。,1.1 陈述性文摘,也叫做论题性(topical)文摘。具有高度概括性。通常只是以标题性的手法介绍论文的论题和内容，以便突出所进行研究的特点。优点：篇幅短小，主题突出。一般不超过150个单词。应用面最广的文摘体裁，适用于理论性、实验性或应用性研究论文。,1.1.1 实验性或应用性研究论文的陈述性文摘一般介绍下列几项内容：,（1）提出问题，即进行了什么实验，或从事 了什么工程技术问题研究；（2）处理了什么问题；（3）正文中是否提供结果或数据；（4） 正文中是否提出了结论或建议。,例1： Investigation on behaviors of AZ31 magnesium alloy sheet in cold deep drawing,Abstract: In order to find out how magnesium alloy sheet behaves in cold working, cold deep drawing experiments (at room temperature) along with Finite Element Analysis (FEA) have been conducted on the popular AZ31 magnesium alloy sheet after annealed under various conditions. The focus of the research has been laid on deformation load, fracture pattern, Limit Drawing Ratio (LDR), anisotropic effect, thickness distribution, and influence of the annealing conditions and the tool conditions on them.,1.1.2 理论性研究论文的陈述性文摘通常需说明下列内容：,（1）所研究问题的领域和性质以及论题是什么；（2）研究的思路或所用的方法；（3） 有没有得出结果；（4）有没有实际应用价值。,例2： Basic theoretical calculations of wind turbines,Abstract: This report treats elements of basic turbine theory. The subjects are: aerodynamics of the horizontal shaft rotor including computation of loads and expected power production; structural static and dynamic analysis of the rotor blades; the use of asynchronous machines as generators for wind mills and various possibilities for control of the generator. The theoretical treatment is everywhere illustrated with examples to facilitate application of theory. All computer codes described in the report are available at Risoe National Laboratory for consulting services.,1.1.3 综述性研究报告需包括下列内容：,（1）涉及的领域或论题；（2） 报告中所综述的各种方法或发展动态；（3）是否得出了结论。,例3： Durability methods development. Volume II. Durability analysis: state-of-the-art assessment,Abstract: A critical evaluation of three analytical approaches is made to determine their applicability and /or potential for analytically assuring airframe durability during the design stage. A suitable analytical format for quantifying durability damage is developed based on U.S. Air Force durability design specifications and durability analysis needs. Air Force durability requirements are briefly reviewed and discussed. Three potential approaches for durability damage analysis are conceptually evaluated and discussed: (1) Conventional Fatigue Analysis (Palmgren-Miner Rule); (2) Deterministic Crack Growth Approach and (3) Probabilistic Crack Growth Approach. The resulting evaluation provides the prerequisite work needed to develop a durability analysis methodology. The probabilistic crack growth approach found to be the most promising for developing the durability analysis methodology under phase 1.,1.1.4 陈述性文摘的行文,以“This report (paper, article,) presents (discusses, describes,) ”开头。句子结构比较单一，也相对短一些。 典型的陈述性文摘：EI-Engineering Index,1.2 资料性文摘,资料性文摘是正文实质性内容的高度缩合，可以在一定程度上有效地起到正文的作用。资料性文摘包含有数据、方法、手段和结果等具体的技术性内容，所以在帮助读者决定是否进而阅读正文方面更为有效。,1.2.1 篇幅,资料性文摘在篇幅上通常比陈述性文摘要长，但一般也以不超过300词为宜。,1.2.2 适用范围,资料性文摘的适用范围比陈述性文摘小。在科技领域里，资料性文摘一般只适用于单项研究课题的文献，如：理论性研究报告、实验性研究报告、应用技术报告、以及新产品、新工艺的研制报告等。,1.2.3 内容,资料性文摘的内容在项目上与陈述性文摘基本相同。 它们的不同点在于： 陈述性文摘只作报导性说明，它向读者介绍正文中“有什么”，而资料性文摘必须提供正文中的实质性具体内容，向读者介绍“是什么”。资料性文摘往往突出新的发现，新的结论，或者独特的见解。但应注意，在文摘中提供的技术数据，只能采用叙述的方式，不宜采用图像、表格等其它方式，公式或结构图在原则上也不宜采用。,例4: Investigation into carbon diffusion in multicomponent iron alloys with chromium, nickel, molybdenum and niobium in the range of solid solutions,Abstract: The effect of chromium, nickel, molybdenum, and niobium on carbon diffusion in iron alloys with 15-20%Cr, 15-20%Ni, 0-2%Mo, and 0-1%Nb in the range of solid solutions is studied by the method of planning the total factor experiment. The coefficients are determined using the numerical version of the method of integral residue and 14C radioactive isotope at 600, 700, 800 C. It is shown that the value of the carbon diffusion coefficient is essentially influenced by chromium concentration variation: increasing the chromium concentration from the average (17.5%) to the upper (20%) level leads to reduction of the carbon diffusion coefficient approximately by 13%. The nickel effect on the carbon diffusion parameters, noticeable at 600C, decreases with the temperature increase. The molybdenum and niobium effect, on the contrary, becomes more noticeable at relatively high temperatures(800C). The effect of chromium, nickel, molybdenum, and niobium on the carbon diffusion parameters is not additive.,1.3 混合性文摘,混合性文摘并不是一种独立的文摘体裁。陈述性文摘和资料性文摘在实际写作中并不互相排斥，往往在同一篇文摘中可同时兼带陈述性和资料性。一篇文摘可以基本上属于其中的一种体裁，而又在某种程度上兼有另一种体裁的特性，这种文摘叫做混合性文摘。 作者在选择文摘体裁时，必须以便于读者在最小的篇幅中，最大限度地了解正文所论述的具体内容为前提。,1.3.1 基本为陈述性，兼有资料性,例5: Numerical and experimental investigations on the effect of the heating strategy and the punch speed on the warm deep drawing of magnesium alloy AZ31 Abstract: The present work has been focused on the warm deep drawing process by superimposing a thermal gradient between the blank center in contact with the punch and the blank flange (which is going to be drawn). Using such a technique the limit drawing ratio of Mg alloys can be dramatically improved. As a case of study, the forming of cylindrical AZ31 cups was investigated. In particular, the attention was focused on the forming temperature (in both the flange region and in the blank center). Finite element simulations were run in order to investigate the stress and strain distribution in the material determined by the temperature gradient and to validate experimental results. Tests highlighted that a LDR equal to 3.375 is possible when setting the temperature of the blank holder at 230C and the punch speed at 6mm/min.,