不对称的

Through analyses of the field tracer migration test results of tritium in unsaturated loess located in semi arid area, it is found that the longitudinal concentration distributions of 3H are symmetry at higher relative concentration and non symmetry at lower relative concentration.

通过氚在黄土包气带现场示踪试验结果的分析，发现3H纵向分布在相对浓度较大时是对称的，而相对浓度较小时则不对称。

For example, it is possible to find a transformation and two bases, so that the matrix is symmetric with respect to one basis and not symmetric with respect to the other.

为了 例如，有可能找到一个转型和两个基地，使矩阵对称的一个方面，而不是对称的基础上对其他。

In the end, it analyzes the coordination contracts of transfer payment under symmetry and asymmetry information.

在对称信息和不对称信息的条件下，给出了基于转移支付的协调契约。

The third part of this thesis is reactive simulating calculation In this section, some well-known auxiliaries are selected to compute in density functional theory B3LYP on Gaussian 03, from which the relationship between reaction active energies of transition states and enantiomeric excess of chiral products homoallylic alcohols isobtained based on relative reactive ratio theory. Using this relationship, calculations on the reaction of more than eight auxiliaries with four other aldehydes are carried out in AMI and MNDO, proving that N,N\'-dibenzyl tartamide has higher enantioselectivity than others in this reaction.

第三部分为计算化学部分，运用密度泛函理论B3LYP方法在Gaussian03软件上对已经报道的几种手性配体参与的醛不对称烯丙基化反应过程进行模拟计算，基于相对反应速率理论找出两种构型过渡态间活化能的差异与产物光学收率之间的关系；并以此为基础，用AM1和MNDO方法对上述合成的几种配体控制的反应过程进行量化计算，从而在理论上证实了N-苄基酒石酸二酰胺配体在醛的不对称烯丙基化反应中具有较高的立体选择性。

Classified by commodity variety, it can be categorized into the counterfeiting of consuming goods, agricultural goods, architectural materials, medical goods, industrial means of production, publication, paper currency and cultural relics; classified by nature, it can be categorized into fake commodities and substandard commodities; classified by information structure, it can be categorized into the counterfeiting of symmetric information and dissymmetric information.

按照商品品种分类，可以分为消费品类假冒伪劣、农资类假冒伪劣、建筑类假冒伪劣、药品类假冒伪劣、工业生产资料类假冒伪劣、出版类假冒伪劣和纸币文物类假冒伪劣；按照性质分类，可以分为假冒商品、伪劣商品；按照信息结构分类，可以分为不对称信息的假冒伪劣、对称信息的假冒伪劣。

The numerical simulation shows that the harmonics at the end of the plateau become continuous and form a supercontinuum with a bandwidth of about 80 eV, from which a 50 as isolated pulse in the transform limited case can be generated, when asymmetric molecules are exposed to a multicycle two-color field, which is synthesized by a 10 fs/800 nm fundamental pulse and a 15 fs/1200 nm control pulse.

通过计算机数值模拟，发现当波长为800 nm，脉宽为10 fs的基频场和波长为1200 nm的控制场组成的多光周期双色场作用于不对称分子时，不对称分子的高次谐波在平台区的末端呈现出光滑的超连续结构。超连续谱谱宽达80 eV，可以支持傅里叶极限脉宽为50 as的单个脉冲输出。

For very long time, many research groups focus on using more than a stoichiometric amount of a chiral auxiliaries to obtain high enantioselectivity. There were mainly two sorts of processes reported on highly catalytic asymmetric addition of Grignard reagents to aldehydes. The former case was to transform Grignard reagent RMgX into other organometal reagents such as R_2Zn and R-Ti derivatives via complicated procedures at extremely low temperature. The later case was to link a chiral ligand to Mg in the form of organomagnesium amides or use chiral amine ligand catalyzing the alkylation of aldehydes.

格氏试剂对醛的不对称加成的报道大多需要大量的手性助剂以获得高的光学活性，而高度催化的格氏试剂对醛的不对称加成主要通过两种途径进行：一种是把格氏试剂转化成其他的有机金属试剂如R_2Zn和R-Ti化合物再对醛进行加成，反应通常在低温下进行；另一种是利用手性镁胺作为中间体或直接用手性胺催化来完成此反应。

Expanding pinacol reductive coupling reaction into asymmetric one with both diastereoselectivity and enantioselectivity may lead to its application in synthesising medicaments and biologic active compounds with structure of vicinal diol. Asymmetric pinacol coupling reaction is also the most compact and effecient method in synthesizing chiral ligands or chiral auxiliary with C〓 symmetry.

将这一反应发展成为既有高度的非对映选择性，又有高度对映选择性的不对称偶联反应在合成许多含有手性邻二醇结构的药物或生物活性物质将有更重要的应用，同时不对称Piancol偶联反应也是合成C〓对称性的邻二醇多用途手性配体或手性助剂的最为简捷有效的方法。

Four symmetrical and asymmetrical pyrylium - squarylium cyanine dyes were synthesized.

合成了四个对称及不对称含叔丁基吡喃鎓方酸的菁染料，通过光谱和元素分析确定其结构，测定了它们的紫外-可见吸收光谱、熔点和溶解性能。

Chiral SalanCrX complexesa saturated version of SalenCr(ⅢX are designed,and in conjunction with an ionic quaternary ammonium salt or organic strong base can efficiently catalyze the asymmetric,regio-and stereoselective alternating copolymerization of CO_2 with rac-PO at mild conditions to afford isotactic-enriched polycarbonates with～95%head-to-tail linkages and moderate enantioselectivity.

本论文在Salen构型配体的基础上，设计合成了一系列手性Salan型铬配合物，并将其与季铵盐/有机强碱组成亲电-亲核双组分催化体系，在室温下可以有效的催化CO_2和环氧丙烷的不对称交替共聚反应，实现了CO_2和环氧丙烷的不对称交替共聚反应的区域和立体化学控制，得到95%的头尾连接单元和中等光学纯度(对映体过量值ee%≈70%)的全同结构的聚碳酸酯。

And discuss some key point of integrated management system design, include hazard identification and risk assessment and risk control in the occupational health and safety management, the measure of satisfaction target of customer, the flawlessness of law system, the integration of the integrated management system and enterprise standardization system, unify lead institution and work orgnization, integreted internal audit and integrated management review.

同时，论述了一体化管理体系构建中的几个主要问题，包括职业健康安全管理中的危险源辨识、风险评价和风险控制、顾客满意度的科学监测、法律、法规体系的完善、一体化管理体系与企业标准化体系的有机结合、统一的领导机构和工作机构、一体化的内部审核和管理评审。

Deepwater Taranaki is investigated for its petroleum potential, using all available seismic data tied to shallow-water wells.

运用与浅水井相关的现有全部震波探测数据考察了深海区塔拉纳基盆地的油藏前景。