二化性

The results indicate that smaller ligands with lower electronegativity give higher catalytic activity.

这表明当催化剂结构中的配体具有较小的空间结构和较小的推电子北京化匀二大学不页创匕学位论文性时，更有利于提高催化效果。

At first, it analyses the visibility processing of complex scene, including: spatial partition technology BSP, quadtree, octree and equational octree which can optimize scene, category of quick visibility estimation algorithm in the 3D scene, portal which can accelerate rendering, level of detail and mesh simplification based on quadric error metrics used to simply models in 3D scene.

首先分析了复杂场景的可视化处理，包括优化场景渲染的空间剖分技术：BSP树、四叉树、八叉树、均分八叉树；其次是三维场景快速可见性判断算法的分类，可加速渲染的入口技术；最后是用于三维场景中模型简化的两个算法：层次细节模型简化技术和基于视点的二次误差度量网格简化。

Experimental process: jing and 3- methyl -2- methyl ethyl ketonesynthesizes by the benzene zong; Again the glacial acetic acidcatalysis produces 2, 3, 3 - trimethyl - 3H - yinduo; Again has thealkylate response production yinduo iodide after the methyl iodide;The iodide takes off molecular HI under NaOH to become freejier thealkali; Adds 5 - nitryls salicylic aldehydes in the ethyl alcohol forthe solvent under if to respond finally produces 6 '- the nitryl yinduolin spiral benzene and pinan; Through the infrared spectrum andthe ultimate analysis irrevocably proved its structure, and studiedthe annulus with to open the annulus the light to send changes colorthe performance, explained in different solvent medium ultravioletabsorption spectrometry solvent effect, and the comparisondiscoloration the response speed number difference, finally mixed itadds to the methyl methacrylate, the peroxidation benzoin formyl in the plexiglass, tested 6 '- the nitryl yinduolin spiralbenzene and pinan in the glass fatigue resistance, thethermostability.

实验过程：由苯肼和3-甲基-2-丁酮合成腙；再冰醋酸催化生成2 ，3 ，3—三甲基—3H—吲哚；再经过碘甲烷发生烷基化反应生成吲哚碘化物；碘化物在NaOH下脱去一分子HI成为费歇尔碱；在乙醇为溶剂下加5－硝基水杨醛与其反应最后生成6'—硝基吲哚啉螺苯并吡喃；通过红外光谱和元素分析确证其结构，并研究了环体与开环体的光致变色性能，解释了在不同溶剂介质中紫外吸收光谱的溶剂效应，并比较褪色反应速率数的差异，最后将其掺加到甲基丙烯酸甲酯，过氧化二苯甲酰有机玻璃中，测试6'—硝基吲哚啉螺苯并吡喃在玻璃中的抗疲劳性、热稳定性。

Based on integral formula, discrete second electrical field is expressed as a sum of elementary contributions coming from charges accumulated on the surfaces of resistivity discontinuity.

基于地下电流场的积分公式，离散化的二次电流场被分解为电性不连续界面上的一系列点电荷电场的代数和。

Inthe paper, the blind inspection is executed by using modular arithmetic, namely, modulus 2arithmetic.(The result is 0 or 1). A algorithm with high transparency and robustness is realizedby smartly combining this arithmetic with binary chaotic sequence.

文中利用模数运算实现了音频水印的盲检测，即利用模2 运算，模2 取余(所得结果为0 或1)，很巧妙地将这种运算与二值化的混沌水印序列相结合，实现了一种不可感知度高，嵌入量大的高鲁棒性水印算法。

The planarity and the average degree of the bond of the initiators are discussed by the full-matrix least-squares on F〓.

通过最小二乘法计算结果，讨论了分子的平面性及键长平均化程度，诠释了分子内电荷转移的趋势及有可能的引发机理。

Its IR spectrogram performed by potassium bromide showed characteristic absorption peaks in the wavelength of 2917, 2849, 1716, 1463, 1382 and 720cm~(-1), respectively.

EZR_(2002)外观为黄色或黄绿色粉末，熔点在74～79℃之间；经溴化钾压片后的红外光谱图显示在2917、2849、1716、1463、1382和720cm~(-1)处有特征性吸收峰；溶于二氯甲烷后的紫外光谱图显示在412nm处有强吸收，在665nm处有次强吸收，还分别在505、535和605nm附近有弱吸收。

Up to 97% ee was also obtained in the asymmetric hydrogenation of the more difficult and less studied 2,3-disubstitued quinoline derivatives.

以手性二胺与金属铱形成的配合物Cp*Ir(CF3TsDPEN)为催化剂，研究了在空气条件下喹啉衍生物的不对称氢化反应。

The effects of reaction temperature, phase transfer agent and the concentration of rhodium catalyst were examined.

研究了采用水溶性铑膦络合催化体系对双环戊二烯的氢甲酰化反应，考查了反应温度、相转移剂CTAB、铑催化剂浓度等对反应的影响。

The auxiliary can be recovered in high yield (81%) only by filtering and recrystallization. Besides, some other aldehydes have been chosen to test the enantioselectivity of N,N\'-dibenzyl tartamide, in comparison with two other allylaborates reagents developed previously by Roush and Brown, respectively. The results show that %e.e. of homoallylic alcohol is superior to that of the former, and approaches the Brown reagent.

产物经S_N2反应得瑞格列萘中间体-甲基烯丙基-2-氯苯基-叠氮甲烷(17)；同时，将筛选出的新型手性配体N-苄基酒石酸二酰胺用于其他几种醛(正丁醛，异戊醛和环己醛)的不对称烯丙基化反应，并与广泛应用的Roush配体(22)和Brown配体(27)相比较，发现其立体选择性优于Roush配体，并接近Brown配体，但明显具有可回收利用的优势。

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％。