化学

When he read about this finding, University of Illinois chemistry professor Eric Oldfield realized that the chemical precursors of the Staph carotenoid were identical to those that led to production of cholesterol in humans.

当读到这一发现，美国伊利诺斯大学化学教授Eric Oldfield意识到葡萄球菌类胡萝卜素的化学前体与那些在人体中生产胆固醇的前体是相同的。

Some basic studies supported by Chinese Natural Science Foundation were also mentioned. Numerous valuable data for chemotaxonomy of pine species were obtained through systematic studies on chemical composition of oleoresin of nearly 60 pine species.

最后提到了由国家自然科学基金多次资助的基础研究工作，通过对近60个松树树种的松脂化学成分的系统研究，得到了松树化学分类的许多有用证据。

In a more complex one-step reaction, bonds both form and break.

在较复杂的一步反应里，既有化学键的形成，也有化学键的断开。

Several transient compounds were synthesized by the homo- and heterogeneous reactions of reactive halogen compounds, In-situ ultraviolet photoelectron spectroscopy and photoionization mass spectroscopy as well as theoretical calculations were used to study their molecular structures, stability and molecular orbital properties, their electronic structures and geometric structures were obtained for the first time; Simultaneously, the electronic structure and thermal dissociation of acetyl peroxynitrate and trifluoroacetyl peroxynitrate which have great importance in the atmospheric chemistry were studied; The substituent effects of series of halopyridines and halothiophenes were studied by the ultraviolet photoelectron spectroscopy method for the first time. The atmospheric chemical reaction between peroxyacetyl radicals with IO radicals as well as the dissociation of the most stable isomer of CH3COIO3 were calculated by density functional theory, it was found that the CH3COOIO2 isomer may be act as a new reservoir of inorganic iodine in the stratosphere.

通过活性卤素的系列均相与非均相化学反应合成了几种瞬态物种，采用原位紫外光电子能谱和光电离质谱结合量子化学理论计算对化合物的分子结构、稳定性以及分子轨道特性进行了研究，首次获得了这些物种的电子结构和几何结构的信息；同时研究了大气中有重要作用的乙酰过氧硝酸酯和三氟乙酰过氧硝酸酯的电子结构性质及热解过程；采用紫外光电子能谱手段首次研究了系列卤代吡啶和噻吩的取代基效应；通过量子化学理论计算研究了乙酰基过氧自由基与IO自由基的大气化学反应及其最稳定异构体CH3COOIO2的解离，发现该物种可能是无机碘化合物在平流层中的储库物种。

Bonding structure and the change of chemical composition at the Cu/ceramic interface are investigated systematically with microanalysis. Furthermore, it is observed that copper bonding to Al〓O〓 ceramic is formed by chemical reaction between Cu〓O within the Cu-Cu〓O eutectic and Al〓O〓 at high temperature, CuAlO〓 as a reaction result is produced, mechanic join and physical osmose are not the main factor.

运用多种显微分析技术，对铜-陶瓷键合界面的微观结构，以及键合前后物相化学成份的变化，进行了系统的研究，在此基础上，明确了Cu-Al〓O〓陶瓷的键合机理；机械交联和物理渗透不是形成键合的首要因素，键合是通过Cu-Cu〓O共晶熔体中的Cu〓O相在高温下与Al〓O〓陶瓷发生了化学反应，形成了牢固的化学键合，同时伴随有一些CuAlO〓物相的生成。

All of those excess chemicals tend to do a lot of harm to your body. The skin in particular is susceptible to injury from chemical exposure or overexposure.

这些过量的化学物质对你的身体都是有害的，而过度地与化学物质接触尤其对皮肤有刺激作用。

In the review, the chemilumines-cence systems in which NBS was used as the oxidant were summarized.

在综述部分，对NBS作为氧化剂的化学发光体系，着重介绍了几种主要反应类型的化学发光机理及其分析应用。

Here, we supposed that the manganese and singlet oxygen coexisted in the acid potassium permanganate system.

第三章酸性高锰酸钾体系化学发光机理研究本文对第二章研究报告中使用的酸性高锰酸钾体系的化学发光机理进行了仔细研究。

In this paper, the structure characters of steroidal alkaloids from Buxaceae were discussed. Using the steroidal alkaloids for the chemotaxonomic characters, the evidences of chemotaxonomy and plant systematics of Buxaceae were studied. The interrelations among three genera, Buxus, Pachysandra, and Sarcococca were discussed.

本文讨论了黄杨科植物甾体生物碱成分的结构特征；以甾体生物碱作为化学分类学的特征物质，初步探讨了黄杨科植物化学分类学的依据和系统位置；同时讨论了黄杨属、板凳果属（Pachysandra，又称富贵草属）和野扇花属3属间的相互关系。

There are 3 main types of evidence for ice ages: geological, chemical and paleontological.

主要有三类：地质学上的，化学上的，古生物学上的。主要有3种证据冰河：地质、化学和古生物。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。