Determination of Critical Rayleigh Number for Binary Solutions in a Nonlinear Theory of Convective Stability

The Rayleigh–Benard convective instability in a cell with horizontal copper electrodes is considered. The space between the electrodes is filled with a CuSO₄ solution. The dependence of the variation in the limiting current of copper deposition, I, which is caused by the formation of convective dissipative structures in the system, on the solution concentration is determined experimentally. The results agree satisfactorily with a nonlinear theory of convective stability that accounts for the electrical forces generated by the formation of a space charge near the electrode, along with the buoyancy forces. This enables one to determine the critical Rayleigh number for the system by extrapolating the linear dependence of I on . The critical Rayleigh number thus obtained agrees satisfactorily with the theoretical value calculated within the linear theory of stability.     

Number 84

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the latter part of the 2006 literature. Previous installment: J. Org. Chem. 2007, 72(1), 303-12.     

Number 75

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the middle part of the 2004 literature. Previous installment: J. Org. Chem. 2004, 69(20), 6957-66.     

Number 83

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the middle part of the 2006 literature. Previous installment: J. Org. Chem. 2006, 71(20), 7923-30.     

Number 85

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the early part of the 2007 literature. Previous installment: J. Org. Chem. 2007, 72 (7), 2699-706.     

Toward a Theory of Diffusion of a Nonionic Surfactant with Variable Aggregation Number in a Micellar System

Since the aggregation number of micelles always grows with concentration, and, in some cases this dependence is noticeable even for spherical micelles, there is a need to revise the theory of micellization, in which the aggregation number is assumed to be constant. This work reformulates the theory of diffusion of nonionic surfactants in micellar solutions with regard to the variability of the aggregation number. A new formula, which expresses the diffusion coefficient of a surfactant via the diffusion coefficients of monomers and micelles, contains an additional factor capable of increasing the diffusion coefficient with the surfactant concentration. However, this factor is not overly strong, and the “old” part of the formula acts in the opposite direction; as a result, the conventional decrease in the diffusion coefficient of a nonionic surfactant remains prevailing. The analytical consideration has been supplemented with numerical calculations, the results of which are presented in the tables.     

An Alternative Approach to Extend Levy Constrained Search in Fock Space to No Integer Electron Number in Density Functional TheorySCI北大核心CSCD

正The Hohenberg-Kohn theorem in density functional theory,as originally formulated,states that if an electron density,ρ_0(r),is the nondegenerate ground state density of an N-electron system with external potential v_0(r),where N is a positive     

关于组分数的思考

对Gibbs相律公式中组分数进行讨论 ,认为在相律推导的条件中应明确R′的限制条件 ,从而使组分数的概念和意义更加清楚 ,在应用时可避免因组分数定义式中的说法和规定不统一而出现的误解和困惑。     

Number of eggs in egg-noodles

The official method to determine the number of eggs present in egg-noodles is the digitonin method. By applying this method the total content of sterols is determined and expressed as total sterols. The official method is time consuming, not very accurate and its performance is very complicated. Its results are not very reliable either because the composition of the wheat is not considered. In this paper some markers are proposed to verify the correct ratio between eggs and triticum durum (TD) semolina used to prepare egg-noodles. Markers are selected ratios between sterols and FAME. The lipid extract is trans-esterified and injected into a gas chromatograph. The ratio between the areas of the selected components gives the markers. This method is proposed to substitute or alternate the official method because is more accurate and time saving.     

动力学参数数目与法方程条件数的关系

多相催化反应动力学研究的基本问题是动力学方程中的参数估计，它一直是动力学研究中的活跃领域·在参数估计中最常用的方法是最小二乘法．早在1947年［刘开始用线性最小二乘法处理动力学模型的数据．1958年在线性最小二乘法中应用置信区间问题［21．1959年MarguardM出非线性最小二乘法问．前人提出如何求非线性最小二乘法的初值［4］，及加权最小二乘法的重要性问，并对最小二乘法在动力学中的应用做了综述卜］．在多相催化动力学研究中，关干线性最小二乘法遇到根本性困难的问题前人未涉及．我们曾在动力学研究中发现线性最小二乘法的法…