Phase Transition and High Piezoactivity of Sr Doped Lead-Free （Na0.53K0.422Li0.048） （Nb0.89Sb0.06Wa0.05）O3 Ceramics

Lead-free piezoelectric ceramics （Na0.53K0.422Li0.048 ） （Nb0.89Sb0.06 Ta0.05 ）03 （NKLNST） ＋ x tool SrCO3 are prepared by conventional solid state sintering method. The specimens with pure perovskite structure show tetragonal phase at x 〈 0.01, and become pseudo-cubic phase at x 〉 0.02. A lattice parameter discontinuity is found in the specimens with 0.004 〈 x 〈 0.0075, along with a great improvement in piezoactivity. The 0.004 mol SrCO3 added NKLNST ceramics possesses outstanding performances of kp = 0.53, kt = 0.26, and d33=309 pC/N. Moreover, the Sr^2＋ modification inhibits the gra/n growth, decreases the Curie temperature, and induces a diffuse phase transition.     

Undercooling and Unidirectional Solidification of CuNi Alloy Melts

Cylinder-shaped CusoNi20 alloy melt is undercooled and solidified by the combination of the electromagnetic levitation technique and the flux treatment method. Nearly constant temperature gradient of 8-10 K/cm is realized for the cylindrical melts with differen~ undercooling levels at the bottom ends. The experimental results reveal that with the increase of the undercoo]ing of the melts from 35 to 220 K, the microstructures undergo transition from coarse dendrites to granular grains, unidirectional dendrites, and finally to equiaxed grains.     

曝光系统离焦对平面全息光栅衍射波前的影响

波前像差是衍射光栅的重要技术指标，它直接影响光栅的分辨率。由光致刻蚀剂记录两束相干光干涉条纹是制作全息光栅的关键步骤。为了提高全息光栅曝光系统调整精度、减小离焦、降低光栅的衍射波前像差，从离焦对反射球面准直镜的准直光平行度的影响程度出发，分析了准直光平行度对全息光栅衍射波前像差的影响。理论分析和数值模拟结果表明，准直镜调整误差直接决定全息光栅衍射波前像差大小。以3种不同刻线密度光栅为例，得出了准直镜调整误差的允许变化范围。     

一种测量次级中子能谱的新方法

采用双飞行时间法创建了一台非常规快中子飞行时间谱仪，排除了用D（d,n)^3He中子源测量8－13MeV能区次级中子双微分截面时源中破裂中子群对次级中子能谱测量的干扰，结合常规快中子飞行时间谱仪的测量，实现了用D（d,n)^3He中子源开展8－13MeV中子能区次级中子双微分截面的测量。     

高炉渣非晶态含量的定量分析方法研究

通过X-ray衍射方法对高炉渣中非晶态与晶态的含量进行了定量分析研究。定量分析过程包括标准样品制备、配样与衍射以及数据处理分析。数据处理包括非晶态衍射峰及晶态峰在一定衍射角度内的积分、线性拟合与定量系数确定。提出了X-ray衍射方法所用的高炉渣标准样品的制备方法,包括100％非晶态标样和100％晶态标样。提出了由100％非晶态和100％晶态为标准样品时,高炉渣中非晶态含量的测定方法,适用于非晶态含量较高(>80%)的高炉渣的定量分析。结合数学处理和X-ray衍射结果,可得到原始高炉渣中非晶态含量和晶态含量,以及相应的比例系数,适用于非晶态含量高的高炉渣(>90%)。     

场发射栅孔阵列的制备

 采用硅的局部氧化技术以及湿法刻蚀技术,利用2.6 μm的光刻掩模板在n型硅片上形成了栅极孔径为1 μm的场发射阴极的栅极空腔阵列,实现了用大阵点尺寸的栅极掩模板制备较小尺寸栅孔阵列。硅的湿法刻蚀溶液采用各向同性的硝酸和氢氟酸混合溶液,刻蚀后空腔的深度和宽度均随刻蚀时间线性增加。同时,由于刻蚀溶液具有较高的Si/SiO₂ 刻蚀选择比,栅极孔径随刻蚀时间增大的速度远低于深度和宽度增大的速度,栅极孔径主要取决于掩模的尺寸和氧化层的厚度。通过选择掩模板的尺寸以及氧化层的厚度,采用局部氧化技术和湿法刻蚀技术能够制备出微米或亚微米的场发射阴极的栅极空腔阵列。     

Characteristics of the magnetic analysis system for a compact MPR-type spectrometer

The magnetic proton recoil(MPR)spectrometer is a novel diagnostic instrument with high perfor-mance for measurements of neutron spectra in inertial confinement fusion(ICF)experiments and high power fusion devices.A compact MPR-type spectrometer dedicated to the research of pulsed deuterium-tritium(DT)neutron spectroscopy of special experimental conditions is currently under design.Analyses of the main parameters and performance of the magnetic analysis system through 3-D particle transport calculations and MonteCarlo simulations and calibration of the system performance as a test using CR-39 solid track detector and α particle from 239pu and 226Ra radioactive sources are presented in this paper.The results indicate that the magnetic analysis system will achieve a detection efficiency level of 10-5-10-4 at an energy resolution of 1.5%-2.1%,and fulfills the design goals of the spectrometer.     

Highly Efficient Simplified Organic Light-Emitting Diodes Utilizing F4-TCNQ as an Anode Buffer Layer

We demonstrate that the electroluminescent performances of organic light-emitting diodes （OLEDs） are significantly improved by evaporating a thin F4-TCNQ film as an anode buffer layer on the ITO anode. The optimum Alq3-based OLEDs with F4-TCNQ buffer layer exhibit a lower turn-on voltage of 2.6 V, a higher brightness of 39820cd/m^2 at 13 V, and a higher current efficiency of 5.96cd/A at 6 V, which are obviously superior to those of the conventional device （turn-on voltage of 4.1 V, brightness of 18230cd/m^2 at 13 V, and maximum current efficiency of 2.74calla at 10 V）. Furthermore, the buffered devices with F4-TCNQ as the buffer layer could not only increase the efficiency but also simplify the fabrication process compared with the p-doped devices in which F4-TCNQ is doped into β-NPB as p-HTL （3.11 cd/A at 7 V）. The reason why the current efficiency of the p-doped devices is lower than that of the buffered devices is analyzed based on the concept of doping, the measurement of absorption and photoluminescence spectra of the organic materials, and the current density-voltage characteristics of the corresponding hole-only devices.     

电光调QCO2激光器的六温度模型理论与速率方程理论比较分析

分别利用速率方程理论和六温度模型理论对Q开关CO₂激光器动力学过程进行了理论分析比较,实验上测得电光调Q射频波导CO₂激光器脉冲激光建立时间及峰值功率与速率方程理论和六温度模型理论计算结果一致.但速率方程理论计算的激光脉冲宽度较“窄”,并且几乎没有拖尾,而六温度模型理论计算的脉冲激光波形有明显的拖尾,符合实际测量的波形.另外,六温度模型理论可以全面反映激光器工作气体中不同分子能级的能量转移过程,因此六温度模型理论分析更全面 关键词： 2激光器')" href="#">电光调QCO₂激光器 六温度模型理论 速率方程理论     

两种非线性反铁磁晶体交界面上磁表面波的传播特性

研究了两非线性单轴反铁磁晶体交界面上表面波的传播特性.理论分析和数值模拟表明:入射电磁波只有同时满足频率阈值和功率阈值条件才能在该非线性波导系统中形成稳定传播的表面波.随着传输功率的不断提高,磁场峰值将由一非线性晶体中跃入另一非线性晶体中,并逐渐靠近交界面.表面波动率变化不会对交界面处的磁场振幅产生影响,频率是影响其振幅大小的唯一因素. 关键词： 反铁磁晶体 非线性表面波