探讨带参数微分方程边值问题的解法

主要讨论带参数微分方程边值问题的逼近值及渐近值解法,并且利用基础解系、边值函数等概念,解决了带参数的微分方程中参数充分小的范围内解的变化趋势.     

博格达山南缘芦草沟组的浊积扇

根据岩性、沉积构造、古生物化石和地球化学标志，系统分析了博格达山南缘广泛发育的二叠系芦草沟组的沉积环境。研究表明：博格达山南缘芦草沟组深湖相沉积十分发育，并在此背景上沉积了近岸浊积扇和远岸浊积扇。其中，深湖相暗色泥、页岩和油页岩构成了良好的烃源岩。同时，认为吐哈盆地前侏罗系具有良好的勘探前景。     

In vitro reactivation of anaphase spindle elongation using isolated diatom spindles

A key step for analysing the mechanochemistry of mitosis would be the isolation of a functional spindle capable of anaphase chromosome movement in vitro. Although Mazia and Dan first isolated spindles in 1952, with one or two possible exceptions, isolated spindles are non-functional. An alternative approach has used permeabilized cells to study anaphase chromosome movement, but these preparations are biochemically and morphologically complex, and hence difficult to analyse. We describe here a simple procedure for isolating diatom spindles which are capable of anaphase spindle elongation in vitro. With addition of ATP, the two half-spindles slide completely apart, with concomitant decrease in the zone of overlap. Electron microscopy reveals decreased numbers of microtubules throughout the spindle after ATP addition and confirms the complete absence of structures beyond the spindle poles. These results are inconsistent with theoretical models of mitosis which suggest that spindle poles are pushed apart by microtubule growth, are pulled apart by external forces applied to the poles, or are released from tension generated during spindle formation. The results are consitent with models that postulate mechanical interactions in the zone of microtubule overlap as a factor in spindle elongation.     

Thiarubrine A, a bioactive constituent of Aspilia (Asteraceae) consumed by wild chimpanzees

Two African species of Aspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.     

Modeling of Coalescence and Separation of Liquid Droplets During Solidification of Immiscible Alloys

Directional solidification methods are being used f or in-situ production of metallic immiscible composites. A quantitative understa nding of the dynamic behavior and growth kinetics of the nucleated second phase during solidification is necessary to produce homogeneous dispersion in solidifi ed composites. This paper presents a mathematical model for describing the grow th of nucleated dispersed phase in the two-liquid phase region ahead of the sol idification front and the entrapment of these droplets...     

On the Construction of Mohr Stress Circle and a Graphic Method in Representing the Stress Components on Different Oblique Planes

The Mohr stress circle for three-dimensional stress is usually determined by equations,which is lack of intuitionistic meanings and difficult to understand. In this paper, the construction of Mohr stress circle is illustrated directly by numerical method. The shortcoming of Mohr stress circle in representing the stress components on different oblique planes for three-dimensional stress is analyzed. A three-dimensional figure is given to describe the variation of normal and shear stress on different oblique planes at one point for the first time.     

添加剂对AN多变晶型影响研究

本文运用热分析的方法对四十余种无机、有机添加剂和几种表面活性剂及水分对硝酸铵(AN)晶型转变的影响进行了研究。结果表明这些添加剂对AN的影响应为多种因素的综合结果。