关于复数和的模与模的和之比的一个极值问题

本文考虑了m个复数的部分和的模的最大值与全体复数模的和之比的下确界ξm。通过引进复数集的对称分解及O-重心集等概念,当m=λ·2~μ不是2的整数方幂时,或当m=2,4时,我们求出了ξm的准确值;当m=2~μ是2的整数方幂(μ≥3)时,我们亦得到了ξm的大小的较为精确的估计式。     

褐马鸡主要传染病及寄生虫病研究

作者应用临床诊断、病理解剖、流行病学、细菌学检查及内外寄生虫检查等方法,检出庞泉沟自然保护区棚养褐马鸡不仅有传染病——鸡新城疫和雏鸡白痢病,而且有寄生虫——鸡异刺线虫和鸡剌皮螨。     

反传递核的构造

本文在已有的自反核、对称核、反对称核的基础上给出一种新的运算——反传递核。     

Roles of flanking sequences in the binding between unimolecular parallel-stranded G-quadruplexes and ligands

G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.     

Physicochemical characterization of <Emphasis Type=Italic>Baizhi</Emphasis> particles by ultrafine pulverization

Baizhi, as a medicinal plant, has been demonstrated to be useful for the treatment of aches and pains in China. The physicochemical characterization of Baizhi particles is greatly influenced by ultrafine pulverization. To study the physicochemical characterization of Baizhi, the raw plant material of Baizhi was ground to 6 μm particles by a high speed centrifugal sheering (HSCS) pulverizer. The micron particles were characterized by optical microscopy and scanning electron microscopy (SEM). Imperatorin is one of the active ingredients of Baizhi, and its extraction yield is determined to evaluate the chemical characterization of Baizhi powder. Imperatorin was analyzed by high performance liquid chromatography (HPLC). The results show that after ultrafine pulverization, the plant cell walls are broken into pieces and the extraction yield of imperatorin is increased by 11.93% compared with the normal particles.     

推进职业资格证书制度 规范家电维修市场

围绕推进职业资格证书制度 ,对规范家电维修市场的要求、作用、现状及对策加以论述     

粉碎过程数学模型

本文介绍了粉碎过程数学模型的基本概念和发展,提出了一个新的动态矩阵模型,分析了各种模型之间的关系和演变,并通过间歇式粉碎过程模型,对其他类型粉碎过程的数学模型作了推导。     

改性膨润土对水中敌百虫和敌敌畏的吸附性能研究

研究了用季铵盐阳离子表面活性剂四甲基氯化铵（TMAC）、四乙基氯化铵（TEAC）和十六烷基三甲基溴化铵（CTMAB）改性的膨润土对有机磷农药敌百虫和敌敌畏的吸附性能。结果表明，用阳离子表面活性剂改性的膨润土的层间距和有机碳含量与改性时所用表面活性剂种类有关；改性膨润土对水中敌百虫和敌敌畏的吸附能力优于原土，并且吸附量随阳离子表面活性剂碳链的增长而增大；同一长链阳离子表面活性剂改性的膨润土对敌敌畏的吸附能力大于敌百虫；温度升高不利于敌百虫和敌敌畏在改性膨润土上的吸附。     

可定量测量的透射式微分干涉显微系统

为满足透明体表面形貌定量测量的需要,研制成功了透射式微分干涉显微测量系统,该系统包括透射式微分干涉显微镜,CCD摄像机,检偏器旋转驱动部件,计算机及相关测量软件。介绍了测量原理、公式、相移干涉方法以及将一台普通反射式干涉显微镜,改装成透射式微分干涉相衬显微镜的关键技术。利用改装好的装置对几种透明体的形貌进行了重构。结果表明:该系统较好地解决了透明体表面形貌的重构问题,在一般实验室条件下,无须采取任何隔振和环境控制措施,测量系统重复性、稳定性均优于2nm,测量范围不受半个波长的限制,有广阔的应用前景。     

高速电力机车二系弹簧系统的改进设计

高速电力机车行驶速度很高 ,轮缘冲击内轨道的激振力显著增强 ,引起一系和二系弹簧系统的刚度降低 ,蛇形运动加剧和晃车现象产生。为此 ,本文对两系弹簧系统的设计进行改进。计算表明 :改进后的两系弹簧系统在各个方向的刚度都显著增加。