查询词典 valent

When treated withlow-valent titanium, a five-member ring 3H,4H-cycl[3,2,2]azine wasobtained.

发现〓可以促进羰基与双键偶联生成了不常见的六元环，制得了4H，5H，5H-3-Hydroxy-cycl[3，3，2]azine。

Starting from 3-benzoyl-5-formyl-indolizine, 3-benzoyl-5-(2'2'-diacetylethenyl)-indolizines and analogs were obtained by the 〓mediated aldol condensation or Wittig reaction. These compounds,promoted by low-valent titanium, gave highly functionlizedcycl[3,2,2]azine derivatives. The coupling reaction proceeded betweenthe carbonyl group and the carbon-carbon double bond, a rare example inMcMurry reaction.

我们以3-苯甲酰基-5-甲酰基中氮茚为原料，通过三碘化钐促进的aldol反应和Wittig反应制备了3-羰基-5-羰基乙烯基中氮茚，随后经低价钛还原偶联，没有生成正常的分子内羰基-羰基偶联产物，而是得到反常的羰基与α，β-不饱羰基的双键偶联产物，较高收率地得到了含多官能团的CycI[3，2，2]azine衍生物。

A catalytic cycle is postulated, in which the oxidative decarboxylation of diphenylacetic acid involves the interaction of a high-valent Mn-oxo species with the substrate.

二苯基乙酸的氧化脱羧可能涉及高价的含氧锰物种与反应物间的相互作用，提出了可能的反应机理。

Zero-valent iron and fluidize technique was successfully integrated in this study for nitrate removal, with three related processes developed, namely fluidized zero valent iron reactor, two fluidized ZVI reactors system, and pressurized CO2/zero valent iron system.

中文摘要本论文成功结合零价铁与流体化技术发展出零价铁流体化反应器、双流体化反应系统以及加压式零价铁流体化反应器等三种处理程序应用於水中硝酸盐之处理。

Nanoscale zero valent iron particles were synthesized by reductive method in aqueous phase. The crystal structure, morphology and size of the particles were characterized using X-ray diffraction and transmission electron microscopy. The influence of temperature, initial acid fuchsine concentration, nanoscale zero valent iron dosage and pH on the removal of acid fuchsine by the particles was studied, and the removal mechanism of acid fuchsine was discussed.

摘 要：采用液相还原法制备零价纳米铁粒子；用X射线衍射和透射电镜表征该样品的晶体结构、颗粒形貌与尺寸；研究温度、酸性品红初始浓度、纳米零价铁加入量及溶液pH值对零价纳米铁粒子脱除酸性品红的影响，并对酸性品红的脱除机理进行讨论。

The results show that the obtained nanoscale zero valent iron particles are mostly in spherical shape with less than 100 nm in size. The acid fuchsine can be removed by nanoscale zero valent iron particles efficiently. The efficiency of removing acid fuchsine from solution is increased with increasing temperature and the dosage of nanoscale zero valent iron particles and decreasing initial concentration of acid fuchsine. The mechanism of removing acid fuchsine by nanoscale zero valent iron particles may include dual functions of absorption and degradation, and the degradation may play a major role in the reaction.

研究结果表明：纳米零价铁颗粒为球形，单个颗粒粒径小于100 nm；纳米零价铁对酸性品红有很好的脱除作用，酸性品红的脱除率随温度的升高、纳米零价铁用量的增加以及酸性品红初始浓度的降低而逐渐增大；纳米零价铁对酸性品红有吸附和降解的双重作用，而以降解作用为主。

Reductive dechlorination of polychlorinated biphenyls by zero-valent metal ;2. Zero-valent metals can be used to treat many kinds of pollutants including Organohalides,heavy metal,nitro-aromatic compounds,azo dye,perchloride and nitrate etc.

介绍了零价金属在处理环境污染物中的具体应用，包括卤代有机物、重金属、硝基芳香族化合物、偶氮染料、高氯酸盐以及硝酸盐等，指出零价金属可以通过还原和混凝吸附等作用有效地治理环境污染物，并分析了零价金属处理污染物的特点和应用前景。

The modified nanofiltration showed a good retention to salts and the retention of the membrane to high valent cation and low valent cation was 95% and 65%, respectively.

荷正电纳滤膜对盐溶液有很好的截留，对盐溶液中的高价阳离子和低价阳离子的截留率分别为95%和65%。

Zero valent iron has been widely used in remediation of groundwater pollution. The potential for using zero valent iron to treat chromium pollution in situ has been concerned in recent years.

零价铁已广泛的被应用於地下水整治复育工作上，近年来，利用零价铁现地处理铬污染的潜力也逐渐被重视。

In chapter 2 and 3, experimentally, using the Angular-Resolved high-resolution fast Electron Energy Loss Spectrometer , at the condition of 2. 5 keV incident energy and 50-60 meV energy resolution, we measured the Optical Oscillator Strength Density Spectra for the excitations of 4p, 4s or 3d electron. The oscillator strengths for excitations of the valent shell 4p electron were obtained, and comparisons were done between presently experimental and previously experimental and theoretical results. The experimental results of different groups agree with each other approximately, but the semi-experientially theoretical results do not match with the experimental results. The delayed maximum in the photoabsorption spectra was discussed. It should arise from the transition of 4p→∈d. For the excitation of the inner-valent 4s electron, the discrepancies for the resonant structures in previous electron-impact results and photoionization results were clarified in present work, which confirms again that the fast electron impact method is suitable to measure the optical oscillator strengths. The autoionization Rydberg series 4s〓ns (n=5, 6, 7) and 4s〓nd (n=4, 5, 6, 7) were identified without ambiguity by the measurement at 0°, 2° and 4°scattering angles. The energy levels and natural widths of the excitations of Kr3d and Ar2p inner shell, including optically allowed and forbidden transitions, were determined. The widths of these inner shell excitations are nearly the same, which was interpreted by the Resonant Auger effect .

在第二章和第三章，实验上，使用角分辨的高能量分辨快电子能量损失谱仪，在2.5keV电子入射能量和50-60meV能量分辨下，测量了Kr原子由价壳层4p到内价壳层4s，再到内壳层3d电子激发的光学振子强度密度谱；得到了价壳层4p电子激发束缚态的光学振子强度，与前人实验和半经验理论结果作了细致的比较，说明几家实验是比较符合的，但半经验的理论计算存在问题；分析了光吸收谱中的延迟极大现象，说明在第一电离阈值以上几个eV范围内的极大值源于4p→εd跃迁产生的延迟极大；对于内价壳层4s激发的自电离区，澄清了前人实验中电子碰撞方法和光学方法在共振结构上存在差异的问题，再一次肯定了快电子碰撞方法是获得绝对光学振子强度的一种好方法；通过在非0°散射角的测量（如2°和4°），清楚地标识了4s电子激发的光学禁戒跃迁自电离里德堡系列4s〓ns（n=5，6，7）和4s〓nd（n=4，5，6，7）；通过在0°和4°散射角的测量，观测并标识了几个新的内壳层光学禁戒跃迁能级，得到了Kr原子3d和Ar原子2p内壳层激发态（包括光学允许和禁戒跃迁形成的）的能级位置和自然宽度，用共振俄歇效应解释了这些内壳层激发态（不管是光学允许还是禁戒跃迁产生的）的自然宽度彼此比较接近的原因。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。