查询词典 dipolar

In this work , the influence of molecular dipolar moment is analyzed, our goal is to discuss cause dipolar moment of ozone.

从分析产生偶极矩的主要因素入手，结合O3的结构来讨论O3分子极性产生的原因。

It is found that the block temperature of the system increase with increasing dipolar interaction strength, so the dipolar interaction can improve the thermal stability of systems.

发现偶极作用能的增加，会导致系统闭锁温度的升高，从而提高系统的热稳定性。

Dipolar cycloaddition reaction is the most useful reaction in fundmental theory of organic chemistry and organic synthesis .

1，3-偶极环加成反应(1，3-dipolar cycloaddition reaction)是在有机化学基础理论及合成方法研究中起重要作用的一个反应。

Thirdly, The preparation of 3-aryl-5-substituted-ethenyl isoxazoles and l-isoxazolyl-2-isoxazolinyl substituted-ethenes was developed through 1, 3-dipolar cycloaddition of nitrile oxides,α-alkylation reaction and another 1, 3-dipolar cycloaddition of nitrile oxides based on polystyrene-supported propargyl selenide.

三、从聚苯乙烯负载的炔丙基硒醚出发，经过腈氧化物的1，3-偶极环加成反应、α-烷基化反应和腈氧化物的1，3-偶极环加成反应固相分别合成了3-芳基5-取代--乙烯基异噁唑和1—异噁唑—2—异噁唑啉取代的-乙烯。

Fourthly, The preparation of 1 -triazolyl-2-isoxazolinyl substituted-ethenes was developed through an one-pot 1, 3-dipolar cycloaddition of NaN_3 and RI,α-alkylation reaction of substituted allyl bromides and 1, 3-dipolar cycloaddition of nitrile oxidesbased on polystyrene-supported propargyl selenide.

四、从聚苯乙烯负载的炔丙基硒醚出发，通过与叠氮化钠和碘化物的一锅法1，3-偶极环加成反应、取代烯丙基溴的α-烷基化反应和腈氧化物的1，3-偶极环加成反应固相合成了1—三唑—2—异噁唑啉取代的-乙烯。

In order to discuss the regioselectivity of nitrile oxide 1,3-dipolar cycloaddition to propyne , 1,3-dipolar cycloaddition reaction of substituted nitrile oxide (RCNO, R=F, NO2, OCH3, OH, COOCH3, CHO, CONH2, H, CH3) with propyne was studied using density functional theory at the 6-311++G** level, and the reaction rates were calculated at different temperature from 200 to 400 K.

用密度泛函B3LYP/6-311++G**方法研究了氧化腈(RCNO，R=F，NO2，OCH3，OH，COOCH3，CHO，CONH2，H，CH3)与丙炔的1，3-偶极环加成反应，并且计算了不同温度下的反应速率常数，讨论了氧化腈上不同取代基R的取代效应和温度对反应区域选择性的影响。

Facing these problems, the half-coupled conservation laws of energy for polar continua, conservation law of energy and Hamilton principle for micropolar multifield theories, principle of virtual velocity and dipolar velocity as well as of virtual stress and dipolar stress for solids with microstructure are proposed.

针对这些问题，提出了半耦合型的极性连续统能量守恒定律、微极多场耦合理论能量守恒定律和Hamilton原理与带有微结构的固体理论的虚速度和虚双极速度以及虚应力和虚双极应力原理等。

A one-step method for the synthesis of aromatic indolizine derivatives byintramolecular 1,5-dipolar cyclization reaction of 2-(2-arylethenyl)pyridinium N-ylidesin the presence of an oxidant has been studied for the first time. In the presence ofelectron-deficient olefins, however, 2-(2-phenylethenyl)pyridinium N-ylides underwent1,3-dipolar cycloadditions and then aromatized in situ by TPCD to produce indolizinederivatives, indicating 1,3-dipolar cycloaddition proceed more readily than 1 ,5-dipolarcyclization in these conditions. Pyridinium disubstituted N-ylides, readily obtainedfrom corresponding pridinium and β-chlorovinyl ketone, underwent thermalintramolecular 1,5-dipolar cyclization to give indolizine derivatives easily.Indolizinecarbaldehyde derivatives were synthesized starting from 2-pyridinecarbaldehyde in four-steps involving 1,3-dipolar cycloaddition reaction.

本文首次研究了2-(2-芳基乙烯基)吡啶N-叶立德在氧化剂存在下的分子内1，5-偶极环化反应，采用一锅法合成了中氮茚衍生物；研究了这些N-叶立德的1，5-偶极环化和1，3-偶极环加成反应的选择性，发现当有缺电子烯烃存在时，优先进行1，3-偶极环加成反应，而不再发生分子内1，5-偶极环化反应；由β-氯乙烯酮方便地得到了烯丙基N-叶立德，他们在加热时进行分子内1，5-偶极环化反应而得到中氮茚衍生物；由2-吡啶甲醛为起始原料，通过1，3-偶极环加成反应等四步反应，得到了重要的中氮茚甲醛衍生物，这些反应都具有条件温和和操作简便的特点，是合成中氮茚衍生物的新方法。

The application results from fluorination showed microwave heating could accelerate chemical reactions markedly. The reaction time could be shortened 50% at least than that of conventional heating. The relationship between fluorinating agents\' structure and their activity was studied systematically. In addition, an anhydrous KF with higher activity was prepared by using expansion effect of microwave heating. As we known, solvents were very important to reaction. The comprehensive study showed some less polar aromatic solvents could be used as dipolar solvents. In addition, they had better effect than dipolar solvents in some occasions, such as fluorination of chlorobenzaldehydes and chlorinated diphenyl ketones etc. The primary applications of ionic liquids were also studied which indicated reactions with ionic liquids as solvents were more efficient and simple.

研究表明，微波是一种节能高效的加热方式，在微波作用下的卤素交换氟化反应具有反应速度快、转化率高、选择性好的优点，其反应时间可较常规加热缩短50%以上；同时也系统地研究了氟化剂种类及制备方式对其反应活性的影响，并利用微波加热的膨化作用制备出了一种活性较高的KF，其活性与喷雾干燥KF相差不大；溶剂对反应具有重要的作用，在此系统地研究了强极性非质子溶剂和中等极性非质子溶剂的应用情况，发现一些中等极性的非质子溶剂如硝基芳烃和氯代芳烃类溶剂在氯代苯甲醛类化合物的氟化反应中具有比强极性非质子溶剂更好的使用效果。

A series of new isoxazolines were prepared by 1,3-dipolar cycloaddition between different mono-substituted styrenes and new 1,3-dipolar compounds which were synthesized by the reaction of N-methylhydroxylamine sulfate with aromatic carbonyl compounds.

以N-甲羟胺硫酸盐和芳香族羰基化合物为主要原料合成了一系列不同的1，3-偶极化合物，并合成了四种不同的单取代苯乙烯。以该系列1，3-偶极化合物和单取代苯乙烯为主要中间体，采用1，3-偶极环加成反应合成了一系列异恶唑啉类新化合物。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。