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riations of Tg with the water content and with the drawing are discussed in terms of the structure in these materials. The increments of ΔCp at Tg are also interpreted using a three phases model.

一般过去时及其被动语态
An analysis of the cure kinetics of several different formulations composed of bifunctional epoxy resins and aromatic diamines was performed. …… All kinetic parameters of the curing reaction were calculated and reported. Dynamic and isothermal DSC yielded different results. An explanation was offered in terms of different curing mechanism which prevail under different curing conditions. A mechanism scheme was proposed to account for various possible reactions during cure.

现在完成时及其被动语态
The partial molar enthalpies of mixing of NaHSO4 and KHSO4 have been measured at 528K by dropping samples of pure compounds into molten mixtures of NaHSO4 and KHSO4 in Calvet calorimeter. From these values the molar enthalpy of mixing has been deduced.
The phase diagram of this system has been confirmed by conductometric and thermal analysis methods. By an optimization method the excess entropy of the liquid mixtures was also calculated.

应理解为上述时态是撰写摘要时常用的几种时态，有时很难区分它们在含义上的严格差异。

这只是从语法功能的角度将其概念化，实际写作英文摘要时，这几种时态并非完全不可互易。

  1 基本特性
  2 时态
  3 语态
  4 语法修辞
  5 一个典型示例
  6 化学常用句式

  3   语态
目前，英文摘要仍以被动语态具多（见上例），这种语态“可以在主语部分集中较多的信息，起到信息前置，语义鲜明突出的效果。”【1】

  主动语态也偶有出现，并有增长的趋势，认为“主动语态表达的语句文字清晰、简捷明快，表现力强，动作的执行者和动作的承受者一目了然，往往那给人一种干净利落、泾渭分明的感觉。”【1】

主动语态举例
We report rheological data on anionic polyelectrolyte solutions of variable chain length and concentration, ……

We have studied the dehydration under atmospheric pressure for …… ,NiNa4(PO3)·6H2O ,between 25 and 700℃ by thermal analyses (TG, DTA), infrared spectrometry and X-ray diffraction. ……

……We find that one component (polyimide) controls the permeability values and activation energies for helium permeation in the blends. ……

……To examine the effect of electric field on the aggregation structure of the particles, we observed light scattering of the suspension under an electric field, and found that the scattering pattern became anisotropic. ……

……We demonstrate the thermally activated nature of theβ-PMMA and β-P(VDF-TrFE) relaxation, with activation energies of 29.3 and 13.5 kcal/mol, respectively. ……

……We refer to the lamellar thickening process as a type of secondary crystallization. ……

概括起来：
·作者告诉读者论述怎样的主题，可用现在时
·用过去时及其被动语态叙述实验方法与过程,；表示实验前业已完成的动作（过去的过去），用过去完成时。例如：
The crystallized samples had been polished before they were etched in a 0.5％ HF solution at a temperature of 25℃ for 2 s ,
·对实验结果可用现在时（表示客观真理）或现在完成时（已取得的阶段性成果）。

关于结构式文摘

据统计，目前世界上约有60％的核心生物医学期刊采用结构式摘要，但此种摘要不适合综述之类的文章。
结构式文摘是按Objective（目的）、Methods（方法）、Results（结果）和Conclusions（结论）逐一阐述论文的梗概。在Objective项，可直接用动词不定式的一般式主动语态，如To provide, To explore, …; Methods和Results 项，可用一般过去时（有时也用现在完成时）及其被动语态；Conclusions 则用一般现在时(参见：韩仲琪，李炳汝，王庆法. 医学论文英文摘要格式及其写作问题. 编辑学报，2002，14（6）：412)

Objective
动词不定式开头
To investigate  …
To study …
To explore …
To examine …
To determine …
To report …
To review …
使用第一人称时，用凡指的we, the author, the authors ,不用I。
如：In this paper we conclude …

Methods
用完整的句子，以被动句和过去时态为主。

Results<本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。