选择性

When metal oxides were supported on γ-Al〓O〓, higher conversions of phenol were obtained, but the selectivties to anisole, a by-product, were also higher.

在使用负载型催化剂催化苯酚与DMC的酯交换反应中，γ-Al〓O〓作载体时的催化性能比SiO〓作载体时好，但产物中苯甲醚的选择性也相对较高。

In order to improve the efficiency of the system, we use anisole/toluene/ TBP as the solvent, in which the concentration of EAHQ is improved to 1.0 mol/L during the recycles of EAQ/EAHQ redox system.

二甲苯／TBP N门，体积比）溶剂中，EAHQ的饱和浓度为 0石2 mol几，用于丙烯环氧化时丙烯相对于 EAHQ的转化率为 96％，生成环氧丙烷的选择性为 88％。

In the acylation reaction between anisole with acetyl chloride, The catalyst of ZnCl〓/HY-98 prepared by MWI had the best catalytic activity and the selectivity of p-methoxy acetopheone. The catalytic active centers were ZnCl〓 dispersed in zeolite and the Bronsted acid sites in HY-98 zeolite itself.

在苯甲醚与乙酰氯的酰化反应中，微波固相法制备的ZnCl〓／Y催化剂有相对较好的催化活性和选择性，起催化作用的主要是分散在分子筛表面的ZnCl〓和分子筛本身的B酸。

L-prolinamide/PPTS system was developed to catalyze Robinson annulation of 1,3-cyclohexanedione derivatives. Using this system, the functionalized carbon chain of Wieland-Wiescher ketone could be synthesized in high enantioselectivity, which was a useful synthon for structural diversity of total synthesis of natural product.

二、发现了L-prolinamide／PPTS体系可以催化Ronbinson环化1，3-环己二酮衍生物，实现含季碳且具有多官能团侧链的Wieland-Wiescher酮高对映选择性的合成，为天然产物结构多样性的合成奠定了基础。

Generally speaking, the reaction types involvingα-oxoketene--acetals mainly include the regioselective addition-aromatization with organometallic reagents, conjugate addition-cyclization with nitrogen nucleophilicspecies, nucleophilic reactions ofα-carbon, acting as odorless dithiol equivalentsin thioacetalization, Michael additions and [5+1] annulation, as well as the synthetic applications based on the above reactions.

一般来说，基于α-羰基二硫缩烯酮化学的反应主要为：与金属有机试剂的选择性加成反应，与氮亲核体的共轭加成反应，α-碳原子的亲核性及相关反应，烷硫基作为硫醇的替代试剂的应用，α-羰基二硫缩烯酮在碳环、杂环化合物合成中的应用等。

The anolyte was acidified by the source gas. The effect of temperature, feed concentration of H〓S and CO〓, and gas and liquid flow rates were investigated.

结果表明，通过控制工艺条件，采用碳酸钠溶液选择性吸收混合气中的硫化氢是可行。

The 5 SLE patients, however, displayed anomalous proliferation and oligoclonal expansion of the T cells was observed in different TCR BV families with different CDR3 sequences.

SLE活动期外周血T细胞TCRβ链CDR3谱系出现明显漂移，提示CDR3的选择性表达可能与SLE的免疫发病机理有关。

Vinpocetine is effective in curing cerebrovascular diseases, which can selectively improve the circulation of brain, promote energy metabolism, regulate the system function of neurotransmitter, protect brain from suffering from damage due to ischemia and anoxemia in many ways, be used in treatment of insufficiency in blood - supply, stroke and symptoms related to aging, and have special effect on recognition and memory.

长春西汀治疗脑血管病的有效药物，它能够选择性地改善大脑的血液循环，促进大脑的能量代谢，调节神经递质系统功能，多方面保护大脑免受缺血缺氧性损害，特别适用于防治脑供血不足、中风以及与衰老有关的症状，并对认知和记忆有特别的效果，目前临床应用非常广泛，现将长春西汀的药理作用及临床应用综述如下。

Toosendanin (〓, FW 574, TSN), a triterpenoid derivative, is an active ingredient extracted from the bark of Melia toosendan Seib et Zucc which is used in Chinese traditional medicine as an anthelmintic vermifuge against ascarids. It was demonstrated to be a selective presynaptic blocker in neuromuscular junction and central synapses.

从驱蛔中药楝属植物根皮中提取的三萜化合物川楝素（toosendanin，〓，FW 574，TSN），是一种选择性影响神经递质释放，阻遏神经肌肉和中枢突触传递。。。

Indoor research indicates that there are remarkable differences in non-preference, antibiosis and tolerance to M. avenae, respectively, among 27 cultivars or lines of spring wheat seedlings, but no remarkable difference in the total resistance.

室内研究表明，在不选择性、抗生性和耐害性方面，27个供试小麦品种幼苗对麦长管蚜的抗性存在显著差异，但总的抗性不存在显著差异。

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％。