Coercivity mechanism in nanophase (Nd–Pr)–Fe–B melt spun alloys

The nucleation mechanism to predict coercivity values in melt-spun exchange-coupled (Nd_1−xPr_x)_yFe_94−yB₆ alloys for various Nd:Pr ratios x, and Fe:RE ratios y, was tested using the dependence of the anisotropy constant K₁ on Pr content x for the minimum nucleation field H_N^min in the modified Brown's equation. Very good agreement was found between experimental data and theoretical values, confirming the predominance of the nucleation of reverse domains over the wall pinning process in the coercivity mechanism of melt spun REFeB alloys.     

过渡金属氢化物和聚集双键化合物反应的研究Ⅲ.用ESR方法考察二茂锆氢化物与RNCS的反应机理

本文用ESR方法考察了Cp₂ZrH) Cl与RNCSR=C₆H₅,c-C₆H₁₁,n-C₄H₉)的反应的过程,结果表明,在这类反应过程中,Zr-H键发生均裂,中心金属锆经过+4-→+3-→+4的价态变化,反应通过自由基机理进行.     

LARGE－TIME BEHMIOR OF SOLUTIONS FOR THE SYSTEM OF COMPRESSIBLE ADIABATIC FLOW THROUGHPOROUS MEDIA

ＬＡＲＧＥ－ＴＩＭＥＢＥＨＭＩＯＲＯＦＳＯＬＵＴＩＯＮＳＦＯＲＴＨＥＳＹＳＴＥＭＯＦＣＯＭＰＲＥＳＳＩＢＬＥＡＤＩＡＢＡＴＩＣＦＬＯＷＴＨＲＯＵＧＨＰＯＲＯＵＳＭＥＤＩＡ￥ＸＩＡＯＬＩＮＧ（Ｌ．ＨＳＩＡＯ）Ｄ．ＳＥＲＲＥ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔ...     

低气压微波感耦氩等离子体空间分布特性光谱诊断

用二维光学多道分析仪研究了低气压表面波型微波感耦氬等离子体的光谱辐射特性?鼳bel反演后,得到了在各种气压和微波功率下等离子体辐射光强和激发温度的空间分布及其变化规律。讨论了此等离子体的激发机理。     

Coagulation of antibody-sensitized latexes in the presence of antigen

The paper describes a study of the kinetics and mechanism of the coagulation of two types of immunoassays using sensitized latexes. The positive response to the first test is based on the aggregation of the gamma globulin (IgG)-coated polystyrene latexes in the presence of IgM rheumatoid antigen. The second test is relative to the heteroaggregation of two types of sensitized latexes induced by the presence of human chorionic gonadotropin (HCG). In the latter test, two identical polystyrene latexes bearing carboxylic acid surface groups were sensitized by covalent coupling of monoclonal antibodies specific for the αHCG determinant on one type of latex and for the βHCG determinant on the other type. Using the Coulter Counter method, the aggregate size distribution c(n) was determined as a function of the number n of elementary constituents, thus enabling calculation of the number N(t) and weight S(t) average sizes of the aggregates. The temporal variations of the average sizes were compared with typical situtions of reaction-limited aggregation processes in order to characterize the mechanism of aggregation induced by antibody–antigen reactions.     

焦点量与鞍点量的关系

对于一般情形,给出焦点量和鞍点量计算与约化的Maple算法,从而统一了焦点量和鞍点量的计算,并给出细焦点与细鞍点的变换,利用变换推导了焦点量和鞍点量的关系．     

应用PDF方法对甲烷射流火焰组分浓度分布的数值研究

本文用k-ε模型和PDF方程相结合的方法对甲烷湍流射流扩散火焰进行了求解，发现Peters等提出的四步反应模型在径向分布预示性能不好，本文对甲烷射流扩散火焰的实际工况进行了分析，提出反应模型的改进方案。改进后的模型所给出的组分浓度分布比原四步反应模型更符合实验结果。验证了修正模型所依据的思想．     

天光一号打靶聚焦系统的研制

 介绍了在天光一号MOPA光学角多路系统中，将6束KrF准分子激光引入靶室的方法以及聚焦系统的研制。用紫外CCD相机测得6束激光聚到平面靶上的焦斑直径为290μm，靶上的功率密度达到8×10¹² W/cm²。     

Study on hypochlorite degradation of aromatic polyamide reverse osmosis membrane

A serious limitation of most commercial polyamide reverse osmosis (RO) membranes is their sensitivity to chlorine attack. By studying the hypochlorite degradation of aromatic polyamide RO membrane, this work was to get some understandings in the prevention of membrane depreciation and develop membranes with improved chlorine resistance. Membrane performances, including water flux and salt rejection, were evaluated before and after hypochlorite exposure under different pH and concentration conditions. The results showed that chlorination destroyed hydrogen bonds in polyamide chains, causing a notable decline of membrane flux especially in acid environment; however, membrane performance was slightly improved after the treatment of alkaline hypochlorite solution for a certain time, which was probably due to the effect of amine groups in barrier layer. Based on the attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) characterizations and performance measurements, the results indicated that N-chlorination reaction of aromatic polyamide was also reversible, in other words, the N-chlorinated intermediate could be regenerated to initial amide with the alkaline treatment before ring-chlorination reaction. This conclusion provided several relative suggestions for membrane cleaning procedures. Finally, a method adopting surface coating was proposed to develop membranes with good chlorine resistance, and the preliminary results showed its potential for applications.