On Two Theorems of Finite Solvable Groups

For a finite group G, let T（G） denote a set of primes such that a prime p belongs to T（G） if and only if p is a divisor of the index of some maximal subgroup of G. It is proved that if G satisfies any one of the following conditions： （1） G has a p-complement for each p∈T（G）; （2）│T（G）│= 2： （3） the normalizer of a Sylow p-subgroup of G has prime power index for each odd prime p∈T（G）; then G either is solvable or G/Sol（G）≌PSL（2, 7） where Sol（G） is the largest solvable normal subgroup of G.     

大米中硒的FI-HG-AAS测定方法研究

研究了原子化器温度、载气流速、KBH4 浓度等条件对流动注射 氢化物发生 原子吸收光谱法 (FI-HG -AAS)测定硒时的影响。建立了FI-HG -AAS测定大米中硒的分析方法。在优化的工作条件下 ,测定硒的最低检测浓度为 0 3 3 μg·L- 1,线性范围为 0～ 5 0 μg·L- 1,相对标准偏差小于 4% ,加标回收率为 94%～ 1 0 2 %。本法克服了传统的间断氢化物发生 原子吸收光谱法分析速度慢、样品耗量大、操作繁琐且因手工进样在进样速度和进样体积上容易带来误差等缺点。方法操作简便、快速 ,灵敏度及自动化程度高 ,已广泛应用于大米及富硒大米中微量硒的测定     

Investigation of charge effects on poling and stability for corona-poled polymer films

The optimal corona-poling temperature of polymer films was accurately determined by measuring the temperature dependence of the in situ second-harmonic (SH) intensity profile under the applied poling electric field. The in situ SH intensity profile was first measured by probing both the surface voltages and the poling currents induced by surface/space charges for the corona-poled polymer films. Moreover, charge effects on the stability of the chromophore orientation were first studied by using the thermally stimulated discharge-current technique. PACS 72.20.Jv; 42.65.Ky; 73.61.Ph; 81.40.Tv     

Envelop solitons in dusty plasmas for warm dust

A nonlinear Schrödinger equation is obtained for the warm dusty plasmas. The modulational instability of envelop soliton is investigated in this paper. Both the temperature of the dust grains and the charge variations of dust grains affect the instability regions of the dusty plasmas. It also affect the amplitude and the width of the envelop soliton.     

Robust H∞ control for linear Markovian jump systems with unknown nonlinearities

This paper studies the problem of stochastic stability and disturbance attenuation for a class of linear continuous-time uncertain systems with Markovian jumping parameters. The uncertainties are assumed to be nonlinear and state, control and external disturbance dependent. A sufficient condition is provided to solve the above problem. An H_∞ controller is designed such that the resulting closed-loop system is stochastically stable and has a disturbance attenuation γ for all admissible uncertainties. It is shown that the control law is in terms of the solutions of a set of coupled Riccati inequalities. A numerical example is included to demonstrate the potential of the proposed technique.     

激光角膜矫正术中所用激光波长的选择

用分光光度计测定了12例兔角膜和1例人角膜的吸收光谱,结果表明波长小于300nm的准分子激光和波长在1.88μm～2.64μm,2.36μm～40μm的激光,均可对角膜进行切割并可望用于激光角膜矫正术。     

激光束偏转法检测金属表面层的缺陷

本文编程计算了由激光光热应产业的金属表面的温度分布和泵浦光的调制频率、金属层厚度等的关系，预言检测浓度缺陷的能力。用激光光束偏转法检测到表面下不同深处的缺陷，并把面扫描幅值信号以三维象和灰度象显示。     

筛前神经及下鼻甲激光切割术治疗过敏性鼻炎29例临床观察

本文介绍了用筛前神经和下鼻甲激光切割术治疗２９例过敏性鼻炎病人，有效率为９７％。随访６个月至２年，除２例于术后６个月复发外，余者均未复发。实践表明这一手术优于翼管神经手术，优点是：１、解剖标志清楚；２、手术操作简便且易于掌握；３、并发症少而不严重。本文对这一手术的方法，术后处置和疗效进行了讨论。     

Brauer第24问题的推广

本文对Ｂｒａｕｅｒ第２４问题［１］作了推广．利用Ｄａｄｅ关于循环块的理论得到如下结果：设Ｇ是有限群，Ｐ是Ｇ的循环Ｓｙｌｏｗｐ子群．设｜Ｐ｜＝ｐａ，ａ为正整数．令Ｐｉ为Ｐ中唯一的ｐｉ阶子群，１ｉａ．则｜Ｃｌ（Ｇ）｜＝｜Ｃｌ（ＮＧ（Ｐｉ））｜的充分必要条件为ＰｉＧ．