不可微泛函拟极小问题解的Hlder连续性

不可微泛函拟极小问题解的Ｈｏｌｄｅｒ连续性于鸣岐，闵泰山（山西大学数学系，太原０３０００６）（北京轻工业学院，１０００３７）金霁（河北工学院，天津３００１３０）１９９２年１１月２７日收到．设Ｇ是ｎ维欧氏空间Ｅｎ中的有界区域，在上定义，对固定的ｘ关于为...     

Preparation and physical characterization of forms II and III of paracetamol

The polymorphic forms II and III of paracetamol were obtained by melting the marketed form I. Under the melting and cooling conditions used, it was possible to obtain forms I, II and III. The recrystallization conditions and the physical properties of forms II and III were investigated by means of various techniques: thermomicroscopy, DSC analysis, infrared microspectrometry and X-ray powder diffraction at room temperature and as a function of temperature. Form III was found to be very unstable. However, its formation seems to be an important intermediate step in the preparation of form II.     

串联系统可靠性虚拟系统法置信下限的小样本性质

本文讨论了具有r个成败型元件串联系统可靠性的置信下限问题。研究了虚拟系统法置信下限的小样本性质,证明了,在通常情况下虚拟系统法置信下限要大于常见的L-M法置信下限.更一般地,本文证明了在成败型试验中,当成功数与试验数之比保持不变时,试验次数的增加将直接缩小成功率置信区间的长度。     

Onn-th commutators with nilpotent or regular values in rings

Then-th commutator for a,b in a ringR is defined inductively as follows: [a,b]₁=[a,b]=ab−ba and[a,b] _n=[[a,b]₋₁,b]. We characterize the ringsR without non-zero nil right ideals in which[a,b] _nis nilpotent or regular for alla,b∈R. We also examine the case whereR is a semiprime ring with involution in which[t ₁, t₂]_nis nilpotent or regular for all tracest ₁,t₂∈R.     

Measurements of climatic parameters and ground-level ozone at Terra Nova Bay in Antarctica

Summary The results of local meteorology, solar radiation and ground-level ozone measurements taken in Antarctica during the second Italian expedition (December 86–February 87) at Terra Nova Bay are presented. During the summer months the site of the Italian base camp is characterized by a thin strip of deglaciated ground, along which the temperature measurements close to the ground and up to 6 m high show a strongly superdiabatic profile. This irregular trend of the temperature in the surface layer is mainly due to the notable incoming amounts of radiation and to the extreme transparency of the atmosphere. This is also shown by the low values of the ratio between total radiation and diffuse radiation. The ground is thus subjected to intense heating, especially in the warmer hours of the day, while the surface layer of the atmosphere will be characterized by strong upward heat fluxes and by turbulent convective movements. Vertical-temperature-profile measurements show an almost forced persistence in the superdiabatic trend, which tends towards isothermic values only as a resultof rapid variations in the direction and intensity of the wind, connected to the downward flux of cold air masses, shown also by the simultaneous increases in ground-level ozone concentrations which would support the presence of dry-deposition processes in the lower layer. However, the complex local orography and the horizontal discontinuity (sea, deglaciated coast, snow-covered surfaces) do not permit a correct application of profile flux relations, normally used in studies on groundlevel dry-deposition. Paper presented at the IV Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 22–24, 1987, Rome.     

CdZnTe核探测器的蒙特卡罗模拟的初步研究

以CdZnTe核探测器的工作原理为依据,探测器内反应的随机性和反应产生的电子空穴对数目的统计规律为物理模型,应用Visual C + + 自行编制了蒙特卡罗模拟软件.模拟了γ射线在CdZnTe探测器中的响应能谱,并将模拟结果与实际器件的测试结果进行了比较讨论.模拟能谱与实际测得的能谱的主峰符合较好.此外,通过分析⁵⁷Co源辐照下探测效率与器件厚度的关系,可以推测探测效率达到最大时所对应CdZnTe探测器的理想厚度     

Realization of optical limiting with a magnetic fluid film

In this paper, optical limiting property in a magnetic fluid film is studied. The relationship between the emergent power and the incident power is investigated experimentally and theoretically. It is found that the limiting threshold is linear with the diaphragm aperture which accord with the theoretical prediction. The external magnetic field will affect the limiting property, and increase the limiting threshold.     

Development of a universal constant rate thermal analysis system for being used with any thermoanalytical instrument

The SCTA method implies to control the temperature in such a way that the reaction rate changes with the time according to a function previously defined by the user. Constant Rate Thermal Analysis (CRTA) is one of the most commonly used SCTA methods and implies achieving a temperature profile at which the reaction rate remains constant all over the process at a value previously selected by the user. This method permits to minimize the influence of heat and mass transfer phenomena on the forward reaction. The scope of this work is to develop a universal CRTA temperature controller that could be adapted to any thermoanalytical device. The thermoanalytical signal is programmed to follow a preset linear trend by means of a conventional controller that at the time controls a second conventional temperature programmer that forces the temperature to change for achieving the trend programmed for the thermoanalytical signal. Examples of the performance of this control system with a Thermobalance and a Thermomechanical Analyser (TMA) are given.     

Local algebras in the representation of MV-algebras

In this paper we present several results about local MV-algebras, extending existing results given for MV-chains. The role of local MV-algebras in sheaf representation and weak boolean product is stressed and the relationship of local MV-algebras with varieties of MV-algebras is analyzed. Presented by S. Pulmannova. Received November 11, 2005; accepted in final form December 20, 2005.     

激光介质的多次吸收不均匀内热源模型

针对激光介质的内热源,以多次吸收作用为基础提出了适用于侧面双向泵浦板状激光介质的不均匀内热源模型,即多次吸收不均匀内热源模型,并与均匀内热源和一次吸收内热源模型进行了对比分析。研究表明,介质厚度及光吸收系数组成的无量纲参数不同时,三种内热源模型得到的内热源分布也有所不同。最后给出了内热源不均匀度及多次吸收模型与一次吸收模型之间的差异在不同目标值下的内热源模型适用准则。