A THEORY OF BLOCKING FORMATION IN THE ATMOSPHERE

In this paper, a new theory of blocking formation was proposed. The nonlinear Schrdinger equation satisfied by nonlear barotropic Rossby waves for the weak shear zonal flow was obtained by using the WKB method. It was pointed out that when the Rossby wavenumbers sarisfied the relation: k/3相似文献   

A DIAGNOSTIC STUDY OF FORMATION AND MAINTENANCE OF BLOCKING SITUATION ON THE NORTHERN HEMISPHERE USING E-P FLUX

In this paper, the variations of the mean flow, the E-P flux and its divergence of planetary waves in the process of the formation, maintenance and collapse of the blocking situation in the second half of February, 1979 are analysed with the transformed Eulerian mean-motion equations.Analysed results show that because the basic flow changes from the easterly into the westerly in the lower troposphere at high latitudes, the planetary wave for wavenumber 2 strongly propagates upwards, and because of the interaction between the upward propagating planetary wave and the basic flow, the westerty is weakened and approaches to the resonant flow of wavenumber 2 in the middle and upper troposphere (then, in the lower and middle Stratosphere). This may cause the anomalous amplification of planetary wave for wavenumber 2, and moreover make the mean flow change from the westerly into the easterly in the lower and middle stratosphere, following the upper troposphere. Therefore, the blocking situation can be formed a     

用计算机模拟技术研究潜影形成的机理

用Monte Carlo计算机模拟技术研究了溴化银立方晶体中潜影形成的机理。根据潜影研究的一些重要实验结果,在设计模拟模型时作了以下基本假定:(1)光照产生的电子在离子步骤发生之前,很快就达到导带与浅陷阱两种状态的平衡,这里除了表面结点位和晶格位错位之外,填隙银离子也能起浅电子陷阱的作用;(2)Ag、Ag₂和Ag₃的形成(成核过程)为低效过程,而Ag₄⁺ 形成后的成长为高效过程;(3)光照产生的正空穴要经历“V”中心,溴原子和溴分子的演变过程,此时可能发生复合反应和回归反应。 模拟参数的估计是基于一些物理测量,如微波光导和介电损耗等的测量结果。模拟结果定量地展示了潜影形成过程中各种反应物,中间物和生成物的产生和变化,并与宏观的实验结果,如感光响应曲线和互易律失效曲线等,相当一致。     

硝基胍热解反应途径的量子化学研究

本文用MINDO/3方法研究了硝基胍热解反应的机理。研究结果表明, 硝基胍热解反应可经历两条途径得到主产物(N_2O、H_2O和NH_3)。这两条途径相互竞争, 但生成N_2O及H_2O的途径Ⅰ要容易进行, 是整个反应的启动步。     

THE MECHANISM OF COPOLYMERIZATION OF VINYL AND DIVINYL MONOMER Ⅵ: A STUDY ON THE MECHANISM OF THE STRUCTURE FORMATION OF CROSSLINKED POLYSTYRENE

In order to study the mechanism of the formation of maeroporous copolymer, the overall reaction kinetics, phase separation and gelation of the S/EGDM in the presence of inert solvents and the physical properties of the eopolymer were investigated and compared with the corresponding system of S/DVB and S/DVB/MMA. The formation of the network structure of the macroreticular polymer was studied and a model of the mechanism suggested.     

关于Liesegang环形成机理的研究

本文研究了Ｌｉｅｓｅｇａｎｇ环的形成，受到两扩散电解质溶液的浓度比、离子浓度积及光照等条件影响。侧重对成环的微观汇聚过程进行了探讨。     

A STUDY ON THE CHEMICAL MECHANISM FOR POWDER CORROSION OF BRONZE ALLOY

A Cu-Sn-Pb alloy modelled after an antique was cast and the powder-corrosion (P-C) was prepared on it under simulated natural conditions. The main components of the corrosion are much like those of the ancient bronze powder corrosion. It is found that chloride, water and oxygen are the essential factors for P-C formation of which chlorine plays the most important role. According to the results of expriments and thermodynamic calculations, the chemical mechanism of the copper desease was studied. It is pointed out that the fast spread of P-C is caused by two vicious circles.     

STUDY ON THE EFFECTS OF TLCP ON PYROLYSIS OF PET AND ITS RETARDANT MECHANISM

The flame retardancy of aromatic thermotropic liquid crystal phosphorus-containing copolyester,TLCP,on PET was investigated.The results show that the presence of TLCP promotes char formation of the substrate and enhances thermal stability of char,hence delay its decomposition.SEM pictures show that the char formed from PET/TLCP is more compact, therefore is more resistant to fire and heat than that from pure PET.Evolved gas analysis by I.R measurements indicates that TLCP would decompose to produce phosp...     

STUDY ON THE PROTONATION MECHANISM OF 2,6-DIMETHYL NAPHTHALENE DICARBOXYLATE

By the study of absorption and fluorescence spectra and the lifetime of fluorescence at room and low temperatures of 2,6-dimethyl naphthalene dicarboxylate (DMN) in different concentrations of sulfuric acid, different interactions between molecules of DMN and sulfuric acid have been observed. These interactions have been revealed by the absorption spectra of charge transfer complex in the ground state, emission of exciplex, absorption spectra of hydrogen bonding interaction, absorption and emission spectra after proton transfer and different lifetimes before and after protonation. The interaction mechanism of DMN and sulfuric acid through first the CT complex and exciplex then hydrogen bonding and finally proton transfer is proposed.     

2-吡唑啉类化合物发光机制的研究

本工作合成了新型的2-吡唑啉类化合物:1-3-二苯基-4-(p-硝基苄叉)-2-吡唑啉,研究了该化合物在室温及低温77K时的稳态光物理行为,结果表明:在标题化合物分子中存在着两种电荷转移机制,其一是从N1→N2→C3→苯基,其二是从N1→N2→C3→C4→P-硝基苄叉,光激发下,两种电荷转移机制相互竞争,且具有不同的发光构象。     

STUDY ON THE FORMATION MECHANISM OF MONODISPERSE PARTICLES IN THE EMULSIFIER-FREE EMULSION POLYMEAIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

The formation mechanism of monodisperse polymer latex particles in the emulsifier-free emulsion polymerizationof methyl methacrylate and butyl acrylate with potassium persulfate as initiator was investigated. A multi-step formationmechanism for the monodisperse polymer particles was proposed. The nucleation mechanism is considered to be thecoagulation of the precursor particles by homogeneous nucleation when the primary particles reach a critical size with highsurface charge density and sufficient stability. It had been proved by a special experiment that the early latex particles formedby the coagulation were stable. The primary particles grow by absorbing monomers and radicals in the polymerization systemand then become colloidally unstable again due to the understandable decrease of particle surface charge density, which leadsto the aggregation of the growing particles and the formation of larger latex pedicles therefrom. Aner the nucleation period,the preferential aggregation of the smaller particles in the propagation process leads to the change of the particles towards auniform size and narrower particle size distribution. The coexistence and competition of homogeneous nucleation,coagulation, propagation and aggregation result in the increase of the polydispersity index (U = D_(43)/D_(10)) in the first Stage,then its decrease in the later stage because of the competition of propagation and aggregation, and the gradual formation ofthe monodisperse particles.     

四氯化碳制备二氯卡宾反应机理的理论研究

四氯化碳制备二氯卡宾反应机理的理论研究李来才（四川师范大学化学系成都６１００６６）关键词四氯化碳反应途径过滤态ＭＮＤＯ方法中图分类号Ｏ６２１．１４６二氯卡宾是有机合成中一个重要的试剂。目前制备二氯卡宾的方法有多种［１－３］，但Ｍａｋｃ－ｓｚａ［４］报...     

丝裂霉素C酸活化机理研究

丝裂霉素C(MMC)是一种广谱抗肿瘤药物,它在体内活化后可以与DNA以共价结合或交联反应等模式相互作用,从而抑制肿瘤细胞DNA的合成。文中首次采用光谱学方法,结合紫外 可见光谱、圆二色光谱手段,提出了MMC的酸活化机理。证明它是一个质子化水解过程,同时推导了酸活化第一步基元反应的反应级数和反应速率常数的计算公式,并计算得该基元反应的速率常数k为3.083×10-4s-1。     

二氧化碳甲烷化机理的研究(英文)

首先对二氧化碳甲烷化的二种机理进行了回顾,并对这二种机理存在的可能性进了探讨。结果表明,二氧化碳甲烷化经过一氧化碳加氢的可能性不大,而经过甲酸根中间体加氢的可能性极大。同时对在一氧化碳与二氧化碳共存时,一氧化碳对二氧化碳甲烷化的影响进行了动力学分析。     

竹红菌素自敏光氧化反应机制的研究

本文对竹红菌素自敏光氧化反应的机制作了较详细的研究,竹红菌素通过自敏光氧化反应生成不稳定的过氧化物,它可以放出¹O₂回到母体化合物,也可以转化为稳定的氧化产物,我们用活泼的单重态氧的接受体捕获到了体系中放出的¹O₂,用吸收光谱的变化证明过氧化物回到了母体化合物。文中还用猝灭实验证实此自敏光氧化反应除涉及¹O₂机制外,还有其它机制起着作用。     

聚苯乙烯磺酸钠与阳离子表面活性剂的相互作用和纳米聚集体的生成

在聚苯乙烯磺酸钠(PSS)的水溶液中,引入阳离子表面活性剂(CTAB或DDAB)使与PSS通过静电相互作用实现聚苯乙烯磺酸盐不同程度的中性化,并进而对PSS/表面活性剂复合物在水中的行为特征、特别是PSS因疏水化而产生的聚集行为以及临界聚集浓度等采用多种方法如溶液的透光率;荧光光谱;荧光探针以及扫描电镜观察等进行了研究,得到一些颇为有趣的结果.结果表明PSS-CTAB或DDAB加成物可自发的形成约70 nm的纳米粒子。而中性化程度则对加成物的构型以及体系的透光率等有较大影响。结果还表明所得具有亲水外壳和疏松的疏水内核的聚集体能容易的使疏水分子进入其中。     

固态废弃物和煤混合燃烧过程中有机氯化物形成机理的研究

对几种煤和城市固体废弃物（MSW）如PVC和纤维素中的主要可燃成分进行了实验研究,热重－质谱－红外（TGA／MS／FTIR）分析以原料和其混合物为对象,收集得到的燃烧特征图显示出不同的热力学行为。结果表明共燃中快速加热比慢速加热形成有机化合物的可能性要大,管式炉中的实验表明在MSW燃烧过程中Cl2是生成有机氯化物的重要媒介,提出的形成机理包括Deacon反应,用纯有机化合物进行的实验证实此反应为一可能的途径。燃烧过程中SO2对Cl2生成的作用也被检查,结果表明SO2的加入可以降低Cl2的生成量,从而大大减少有机氯化物的生成。     

STUDY ON SOLUBILIZATION MECHANISM IN THE SYNTHESIS OF HIGH MOLECULAR WEIGHT POLY(p-PHENYLENE TEREPHTHALAMIDE)

The salts dissolved in the amide solvent play an important role in the synthesis of high molecular weight poly(p-phenylene terephthalamide) (PPTA). The solubilization of salts was investigated in this paper. The effects of association-dissociation equilibrium of salts and the solvation of their ions as well as hydrogenbond on solubilization were discussed in some detail. The effects were attributed to cations and anions of salts respetively. Finally, the equation of solubilization was established according to the experimental results and some thermodynamic laws. The relations between molecular weight of PPTA and the solubilization were discussed.