连续灰度铁电液晶器件制备

采用N*-Sc*序列相铁电液晶,通过控制在N*-Sc*相变时施加电压的频率和幅值,制备了不同分子层排列结构的器件,获得了“V”字形和半“V”字形的电光特性曲线,从而可以实现连续灰度.根据铁电液晶自发偶极矩与电场力矩的相互作用原理,分析了器件形成不同分子层排列结构及呈现“V”字形和半“V”字形电光特性的原因.     

具有表面凹坑的半无限体三维应力集中系数有限元研究

利用ANSYS有限元软件对半无限体表面球形和半椭球形凹坑的三维应力集中系数进行了计算，该方法简单易行，省时省力；并将所得数据与试验结果作了对比，两者吻合较为一致，说明利用该软件分析三维应力集中问题有效可行。研究结果表明：应力集中系数随泊松比μ、曲率r及凹坑与结构相对尺寸的增加而变大；对于椭球凹坑，在深度一定时，增加凹坑与表面相交面积，可以减小应力集中系数，削去部分的形状，以与凹坑相切，且在载荷方向上有长轴的椭圆或圆弧组合为宜。     

自适应陷波器在机抖激光陀螺信号处理中的应用

首先利用极零点受限自适应陷波器对二频机械抖动激光陀螺输出信号利用预处理,然后再进行低通滤波器处理的方法,不仅有效地消除了抖动输出,而且减小了由FIR滤波器引起的时间延迟。     

有限深V型势阱中总折射率的改变

研究了有限深V型势阱折射率改变，并且利用量子力学中的密度矩阵算符理论和迭代法导出了一次，三次谐波极化率系数.最后，以GaAs有限深V型势阱为例作了数值计算.数值结果表明，减少入射光强度，或增加电子浓度使总折射率改变变大.     

Closed-form solutions for the frequency shift of V-shaped probes scanning an inclined surface

The analytical method to determine the frequency shift of an AFM V-shaped probe scanning the relative inclined surface in non-contact mode is proposed. If the tip is not perpendicular to the surface plane, the lateral force to the tip will occurs. Consequently, there exists a moment to the end of probe. The closed-form solution of the partial differential equation with a nonlinear boundary condition is derived. The error of transforming the distributed-masses system into lumped-masses one in the force gradient method or the perturbation method is eliminated. The dimensionless parameters are introduced for reducing the numerical transaction error. The limiting case such as a uniform or tapered beam can be obtained easily from the general system. The assessments of the force gradient method, the perturbation method and the propose method determining the frequency shift of a V-shaped probe are made. It is discovered that increasing the absolute inclined angle θ decreases the frequency shift especially for a small tip-surface distance.     

Influence of Si doping on the optical and structural properties of InGaN films

Influence of Si doping on the optical and structural properties of InGaN epilayers with different Si concentrations was investigated in detail by means of high-resolution X-ray diffraction (HRXRD), scanning electron microscope (SEM), Cathodoluminescence (CL) and photoluminescence (PL). It was found that a small amount of Si doping in InGaN could enhance luminescence intensity, improve the crystal quality of InGaN and suppress the formation of V-defects in InGaN. Further investigation by CL showed that V-defects act as nonradiative center, which lower the luminescence efficiency of InGaN. Based on above-mentioned results, one possible mechanism of influence of Si doping on the formation of V-defects in InGaN was also proposed in this paper.     

Synthesis,thermal reactivity and structure of 1,2-bis(4-hydroxy-3-methoxyphenylethynyl)benzene

The crystal structure of the new enediyne 3 was determined by X-ray diffraction. 3 crystallizes in the orthorhombic space group Pbca (No. 61) with a = 12.7148(9) Å, b = 7.4872(8) Å, c = 38.890(4) Å, = = = 90 and Z = 8. The three-dimensional structure is characterized by an 8-membered cyclic array linking four molecules of 3 by hydrogen bonding between phenolic and methoxy groups. Furthermore, stabilization by –-stacking and CH s interactions is present. The important cd distance (between the two terminal acetylene carbons of the enediyne) which is relevant for the Bergman cyclization, was determined to 401 pm, being in good agreement with the high cyclization barrier ( G = 147.9 kJ mol^–1 at 220C) that was determined by differential scanning calorimetry (DSC).     

Laser peening of aluminum alloy 7050 with fastener holes

The fatigue properties of laser peened aluminum alloy 7050 specimens with fastener holes were investigated.The surface profile and residual stress induced in the shock affected zone were characterized.Then,the fatigue specimens with notch were treated by laser peening(LP),and the fatigue lifes of LP-treated specimens were measured and compared with base materials without LP.The results indicated that LP improved the fatigue lifes of all tested specimens.The average fatigue lifes of specimens treated by LP before hole-drilling were 173% longer than those of untreated samples and had better effects than those specimens treated by LP after hole-drilling.     

焊条药皮中稀土氧化物向焊缝中过渡机制的研究

通过向焊条药皮中加入稀土氧化物的方法，研究了在焊条药皮中加入不同种类、不同含量的稀土氧化物对焊缝金属低温冲击韧性、显微组织以及扩散氢含量的影响。实验表明，在焊条药皮中添加适量的稀土氧化物可以细化焊缝组织、增加针状铁素体的含量、提高焊缝金属的低温冲击韧性和降低焊缝中扩散氢含量，这是一种经济有效的向熔池中过渡稀土元素的方法，可以在焊接材料中发挥稀土元素的特殊作用。从焊接冶金的角度出发，深入研究了焊条药皮中稀土氧化物向熔池中过渡稀土元素的机理、规律及其影响因素。研究表明，焊条药皮中的稀土氧化物在熔滴的高温阶段可以分解出稀土活性原子并过渡到熔池中，参与焊接冶金反应，对焊接熔池起到进一步脱硫去氧的作用。