SCI论文写作之Results & Discussion（二）：句与句之间的逻辑！

前言：

    上一期内容中，我们主要介绍了Results & Discussion写法中的一个基本原则：先摆现象，讨论完了才能给出结论。今天接着来分享一下Results & Discussion里面非常重要的一点：逻辑结构问题，希望对大家有所帮助。同时再次邀请对写作感兴趣的，愿意分享自己心得和经验的朋友加入我们（[e-mail]），共同繁荣这个版块，谢谢！

今日分享：

    撰写学术论文的目的是希望所发现或者发明的内容能够得到大家认可。因此，受到认可是学术论文最核心的一点。而要想说服别人，很重要的一点必须条理清楚，逻辑严密。事实上，任何一篇科学论文的内容都是片面的，只是反映了作者在当时当下所认知的程度，论文中可能还会存在这样或者那样的不足。而好的学术论文不是拼命地告诉别人我这个东西已经登峰造极，完美无缺了，而是用数据，用严密的逻辑告诉别人：从目前的研究结果，我们可以得出哪些结论，而这些结论对整个领域的发展有哪些重要启示。

    那么逻辑结构体现在哪些地方呢？句与句之间，段与段之间！今天先介绍下句与句之间的逻辑关系，口说无凭，实例为证：

1. 选用逻辑关系

参考文献：G. J. Hutchings et al. Science, 2016, 351, 6276.

  A limiting factor in achieving high selectivity toward H2O2 with Au-Pd/TiO2 catalysts prepared by the wet impregnation method is that the catalyst nanoparticles exhibit a variation in composition with particle size, with the smallest particles being Pd-rich (传统催化剂选择性的局限性). These small Pd-rich NPs are likely to be highly active for H2O2 synthesis and also for its subsequent hydrogenation and decomposition, as has been shown when AuPd catalysts are prepared by colloidal techniques with particle sizes typically 2 to 4 nm (限制选择性的原因). In the case of the Sn-Pd system, the small Pd-rich NPs are often associated with the amorphous SnOx films（本实验中的发现）. We postulated that it might be possible to further decrease the H2O2 degradation activity of the catalyst by inducing encapsulation of the ultrasmall Pd-rich NPs by this SnOx film（基于已有理论和现有发现做出的推论）. We therefore used subsequent thermal treatments in an attempt to induce a strong metal-support interaction (SMSI) between the Pd and SnOx layer (根据推论设计的实验方案). We first added a low-temperature reduction step (200°C, 2 hours, 5% H2 in Ar), which made the catalysts stable to multiple reaction cycles (实验操作). However, the H2O2 degradation activity increased markedly, from 65 mol kg−1 hour−1 to 300 mol kg−1 hour−1; this rate increase was associated with the reduction of Pd2+ to metallic Pd, as shown by XPS (实验结果). Metallic Pd is known to be a more effective H2O2 hydrogenation catalyst (对实验结果的进一步解释).

    这一段一共有9句话，每句话所要表达的意思我都用红色字体进行了标注。1）首先介绍了传统催化剂Au-Pd/TiO2在选择性上的局限性；2）介绍了这种局限性的具体原因；3）本实验中的发现；4）基于已有理论和现有发现做出的推论；5）根据推论设计的实验方案；6）根据推论设计的实验方案；7）实验操作；8）实验结果；9）对实验结果的进一步解释。可以看得出来，作者在写作时层层递进，这是研究思路的内在逻辑。而为了更好地体现这种逻辑，作者在文字上也有所承接（请注意上面一段文字中蓝色字体标记的内容）。比如第一句话中引出了Pd rich这个概念，然后第二句话将Pd rich NPs的具体影响进行了进一步地解释（Pd rich NPs就是这种递进关系的衔接词）。而类似的，第三句话，作者还是通过Pd rich NPs从文献拉回本文的实验结果。第四句话中更是针对Pd rich NPs提出了推论。类似的第八句和第九句通过metallic Pd将两个句子衔接在一起，体现出了递进的关系。

温馨提示：并列结构是所有逻辑结构中最弱的，如果有递进关系，请用递进，如果有因果关系，请用因果关系！文字之间存在逻辑关系，读者读起来会觉得很顺畅，而相反如果文字之间没有逻辑关系，只是简单地罗列，则会显得很生涩，言之无味。

2. 使用连接词

另外一种更加简单地体现句与句之间的逻辑关系是使用连接词.下面简单列举一下一些基本的连接词：

表示递进的：then, subsequently, in addition, besides, what is more, moreover, furthermore, in order to...further, 等等；

表示转折和让步关系的：but, however, nevertheless, nonetheless, on the contrary, on the other hand, in contrast, instead of, even so, though, although, despite, regardless of, in spite of, as opposed to等等；

表示层次关系的：firstly, first of all, to begin with, secondly...finally, last but not least, afterwards,simultaneously, at the meantime, meanwhile, eventually等等；

表示因果关系的：because, because of this, since, for this reason, thanks to, due to, owing to, seeing that, on account of, therefore，as a result, hence, consequently,  accordingly等等；

表示归纳总结的：in conclusion, in summary, in sum, in short，overall,等等;

表示条件关系的：unless, otherwise, only if, if only, suppose that, as soon as, in case that, providing that, given that等等。

这里依旧举一个简单的离子：

参考文献：Liu, J. and Fan, J. et al., Catal. Sci. Technol., 2014, 4, 441-446.

  To further confirm the alloy structure, HRTEM and line-scanning analysis were employed. As shown in Fig. 1c, the lattice fringes of Pt1Pd3 display interplanar spacings of 0.223 and 0.192 nm in the particle, which match well respectively with those of the (111) and the (200) planes of the fcc PtPd alloy. On the other hand, the compositional line profiles of Pt and Pd cross an individual particle shown in Fig. 1d also suggest the NPs to be alloy with homogeneous distributions of elemental Pt/Pd. Moreover, as can be seen from Fig. 1a, the PtPd NPs are well dispersed in the m-SiO2 framework and the sizes of PtPd alloy NPs are rather small with a narrow size distribution (4.1 ± 0.6 nm). The mesoporous SiO2 framework is highly ordered, suggesting that the presence of PtPd NPs does not affect the mesoscopic structure of the oxide support. These results were also confirmed by SAXS data and N2 adsorption–desorption data. As shown in Fig. 2, the interplanar distance of the (100) plane calculated from the SAXS analysis are both 10 nm. Meanwhile, the results from N2 adsorption–desorption data confirm that both Pt1Pd3–m-SiO2 and m-SiO2 have characteristics that are typical of mesoporous materials, and they possess similar BET surface areas (422.8 m2 g−1vs. 439.4 m2 g−1), indicating that the introduction of PtPd has little influence on the structure of the MMOs.

    这一段话是典型的对材料微观结构进行表征的结果的叙述，是R&D里面最常见的看图说话形式。而为了让这些表征手段关联起来，作者采用了很多连接词（蓝色字体部分）。这些连词的使用可以让句与句之间关联更加紧密，从而能够结合多种表征手段来综合说明材料的微观结构信息。

备注：本文出自浙大化学系范杰教授课题组，第一作者为刘娟娟博士，现为杭州电子科技大学材料与环境工程学院副教授。

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