Cyclotomic Linear Codes of Order $3$

In this correspondence, two classes of cyclotomic linear codes over GF(q) of order 3 are constructed and their weight distributions are determined. The two classes are two-weight codes and contain optimal codes. They are not equivalent to irreducible cyclic codes in general when q > 2.     

The critical pressure and impeding pressure of Al evaporation during induction skull melting processing of TiAl

In this article, two key pressures, the critical pressure P _crit and the impeding pressure P _impe of elemental evaporation, are defined and studied based on the calculation relationship between the evaporation loss rate N _m and the chamber pressure P during melting of titanium-aluminum alloys. When the chamber pressure is below P _crit or above P _impe, N _m tends to the maximum or the minimum value and remains almost unchanged. However, if P _crit<P<P _impe, with the increase of the chamber pressure, N _m declines sharply. A method has been put forward to calculate P _crit and P _impe of Al evaporation in a Ti-XAl (at pct) (X=25 to 50) melt. The calculation result shows that P _crit or P _impe is a second-order function of the molar percentage of Al and the melt temperature.     

Preparation and characterization of organic-inorganic poly(ethylene glycol)/WS2 nanocomposite

Layered nanocomposite PEG/WS₂, intercalating oligomeric poly(ethylene glycol) (PEG6000) into the tungsten disulfide host galleries, was synthesized using the exfoliation-adsorption technique. X-ray diffraction revealed that the intercalated oligomer within the host galleries is in a double-layer arrangement with an interlayer expansion of about 8.8 Å. The optimum conditions were explored to prepare the single-phase product with a composition of Li_0.12(PEG)_1.51WS₂. Thermal analyses suggested that the resulting material shows good thermal stability, with the decomposition of the interacted oligomeric chains within the disulfide galleries occurring at around 258 °C. Despite high conductivity of the host material, those of the PEG/WS₂ nanocomposite were found to be high in the order of 1 × 10⁻² S cm⁻¹ at ambient temperature, resulted from the host guest-host charge transfers.     

钢筋砼矩形截面受弯构件优化设计

对钢筋砼矩形截面受弯构件提出一种优化的方法。     

我国职业教育法规中受教育者的权利主张

人本理念,是在对当代社会发展过程中人的主体地位和作用日益突出的反思中,提出的一种发展理念,是一种对人在社会发展中的主体作用与地位的肯定.教育科学中的人本理念,关键是要以学生为本,坚持"一切为了学生、为了一切学生、为了学生一切".     

暖通空调计算机辅助广义设计模式探讨

本文在研究人类设计技能模型的基础上，建立暖通空调广义设计过程模式，提出暖通空调广义设计过程及其CAD系统的信息模型，并以此为基础建立了暖通空调广义CAD系统的框架。     

高油价下我国石油化工的发展对策思考

改革开放20多年来，中国经济向全球展示了持续快速的增长，作为支柱产业的中国石化工业也一直保持着良好的增长势头，得到了稳定快速的发展，尤其在“十五”期间，中国的石化工业在世界石化业中的地位有了突破性的提升。     

环氧基的PCB对无铅组装的兼容性

综述了环氧树脂基的PCB与无铅化组装的兼容性问题。经过大量试验表明,常规的FR-4基材和双氰胺固化的高Tg基材是不能满足无铅化组装要求的,而采用酚醛固化的中等-Tg的环氧树脂基材是可能成为无铅化组装用基材的。同时,PCB制造过程也起着重要的作用。PCB设计和再(回)流焊的加热梯度也影响着无铅化的性能。     

基于通信信道的视频传输系统的设计

提出了一种利用PCM基群信道进行视频信号传输的方法,介绍了传输系统的工作原理,对视频编码器进行了较为详细的分析,并采用数字信号处理器作控制器,实现了视频信号的实时传输。     

Fisher最优分割法在星星哨水库汛期分期划分中的应用

Fisher最优分割法是对有序样本进行最优化分段的一种数学方法。本文利用该方法对星星哨水库汛期进行相应的划分,结果表明该方法是可行的。因此,可利用该结果对分期实施不同的汛限水位,使水库的防洪和兴利效益达到最大。