选择反应

The effect of monomolecular reactions and bimolecular reactions on the yields of propylene and dry gas was investigated in a fixed-bed micro-activity test unit using n-hexadecane and Daqing VGO as feedstocks respectively, under various reaction conditions and catalyst types.

在固定床微反实验装置上，选择正十六烷和大庆蜡油为原料，通过改变反应条件和催化剂类型研究了单、双分子反应对丙烯和干气生成的影响。

There was significant difference among monoterpene volatiles released from healthy, weevil damaged trunks of Pissodes punctatus and their branches. Walking P. punctatus in maturation feeding and sexually matured stages displayed different olfactory responses toward monoterpenes in a Y-tube olfactometer.

通过GC-MS分析，发现健康的与遭受华山松木蠹象Pissodes punctatus Langor et Zhang危害的华山松Pinus armandii Franch树干以及华山松枝梢释放的挥发性单萜烯在含量上存在较大差别；利用Y-型双向选择嗅觉仪进行的室内趋向反应实验发现，处于补充营养期和交尾产卵期的华山松木蠹象对单萜烯表现出不同的趋向反应。

The results indicate that female wasps deposit HMPs on the chorion of host eggs with her ovipositor near the end of egg-laying process. Na ye females do not posses the ability for recognizing the marking pheromones and have to obtain the ability though the learning process, in which the wasp inserts her ovipositor into a host egg to determine whether the egg has been parasitized followed by antennal drumming on the exterior. Once the learning process is completed, the female wasp will be able to discriminate between parasitized and unparasitized hosts and reject a parasitized egg by simply drumming on the exterior of the egg. Learning plays an important role in reducing initial rejection time when an unsuitable host is encountered. Female wasps of T. astriniae can quickly learn to associate the presence of a HMP on host egg chrion with the internal status of the egg.

研究结果表明，玉米螟赤眼蜂的寄主标记信息素是在其产卵过程中的收场阶段由产卵器产生的，并且标记在寄主卵表的化学物质；玉米螟赤眼蜂对标记信息素的识别不具有先天性，其必须先用产卵器插入寄生卵来检测是否被寄生，然后其触角不停地敲击，通过学习获得对标记信息素的识别能力，从而放弃了对寄生卵的选择，学习对初始放弃时间有着重要影响，改善了其对寄主搜索效率，这种学习行为是与寄主联系在一起学习的，它能根据寄主被寄生与否而对标记信息素作出反应与不反应。

Therelationship of the amount of catalyst and the ee% of product was seen to be negative nonlin-ear. Catalyst 3 was used in the enantioselective addition of diethylzinc to aromatic aldehydesand gave good results. The configuration of products was determined by the configuration ofthe catalysts' chiral carbon linked with hydroxy group. Using β- amino alcohols bearing only one chiral center as catalysts for the enantiose-lective addition were studied. D-N, N-dialkyl-2-amino butanol gave poor catalytic effect be-cause of their structure. The configuration of the product is the same as the catalyst. Anotherkind of β- amino alcohols - phenylglycine derivatives and valine derivatives have chiralcenter on the carbon linked with amino group. Catalyzed by-phenylglycine derivatives 6,7, 9, 10, the reactions gave satisfied results. The optical yields exceeded 80%.

在探讨了含有两个手性中心的β-氨基醇之后，选择了只有一个手性中心的β-氨基醇，一是手性中心为连羟基的手性碳原子：D-N，N-二烷基-2-氨基丁醇；二是手性中心为连氨基的手性碳原子：D-苯基甘氨酸衍生物和L-缬氨酸衍生物。D-2-氨基丁醇的催化效果不太好，这与其结构的空间位阻较小有关系，反应产物与连羟基手性碳构型一致；由苯基甘氨酸和缬氨酸出发合成五种β-氨基醇6-10，研究了不同ee％的-6作用下的二乙基锌-苯甲醛加成反应，发现该催化剂具有不对称放大效应；-7，9，lO的催化效果也比较令人满意，光学产率80％以上，所得产物构型与催化剂构型一致。

With the characterization of NMR and IR, combining with the synthesis of active species and studies of their structures, it is suggested that the hydride [RuHCl(PPh3)3], being favorably formed in the acid media, exhibited higher activity in the reduction of the C=C bond, while the hydride [RuH4(PPh3)3], being preponderantly formed in the basic media, showed activity and higher selectivity towards the C=O reduction.

通过核磁、红外等表征手段，并结合可能催化活性配合物的合成和结构研究，推测了在非水介质中对C=C和C=O双键起到活化作用的催化剂活性物种和可能的选择加氢反应机理，即，催化剂[RuCl2(PPh3)3]在酸性环境下倾向于生成[RuHCl(PPh3)3]物种，该Ru-H物种对C=C双键加氢反应表现出较高的活性；而碱性环境下则易于生成[RuH4(PPh3)3]物种，该Ru-H物种对C=O双键加氢具有较高的催化活性。

As an ideal prime immunization vaccine,the DNA vaccine has the advantages of high purity,continuous expression of antigens with low dose, repeatable immunization and inducement of memory CTL with high titer.Similarly, recombinant virus can not only highly express the target antigen,simulate the inducement process of virus infection on body immunity,and induce various cytokines,but also be beneficial to the interaction of high-affinity antibodies with T cell receptors,and the generation of Th1 reaction and CTL reaction.

DNA疫苗抗原纯度高，持续表达低剂量的抗原，可多次重复免疫以及诱导高效价记忆性细胞毒性T淋巴细胞反应，是理想的用于初次免疫的疫苗；重组病毒能高效表达目的抗原，模拟病毒感染诱导机体免疫的天然过程，能诱发多种细胞因子，而且有利于高亲和性抗体和T细胞受体的选择，可以有效地产生Th1型和CTL反应。

A commercial and practical synthesis rout with-2-(3-acetoxy-l-me-thyl-l~propenyl)-5,5-dimethyl-l,3-dioxane as starting material by couple,oxidation, Ramberg-Backlund and deprotection is chosen and studied in this paper.

本文选择了以2-(3-氯-1-甲基-1-丙烯)-5，5-二甲基-1，3-二噁烷为原料，经偶连、氧化、Ramberg-Bcklund反应及脱保护基四步反应的合成路线，对该中间体进行合成研究。

Flavone and pyrocatechol were chosento act as model compounds of different structure aspects of flavonoids and theirreactions with α-hydroxyl ethyl peroxyl radical were studied. The rate constants of thereactions of α-hydroxyl ethyl peroxyl radical with flavone and pyrocatechol weredetermined to be 〓 and 〓,respectively.

我们又选择了黄酮体和邻苯二酚作为黄酮类化合物的结构模型，用脉冲辐解的方法研究了它们与α-羟乙基过氧自由基的反应动力学，得到黄酮体和邻苯二酚与α-羟乙基过氧自由基的反应速率分别为〓和〓〓。

I have intentionally chosen this very strong word for a purpose. If you react against it, what does your emotion and reaction reveal about who you are?

我刻意选择使用这么重的词语是有一个目的：如果你的反应是抗拒，你情感所彰显出来的反应显示出你是一个怎样的人？

The effects of reaction temperature, time and the preparation conditions of the catalyst were studied also.

同时考察了反应温度、时间、以及催化剂制备方法对乙醇选择氧化反应的影响。

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％。