气垫导轨上运动物体加速度测量方法的改进

利用计数计时测速仪测量气垫导轨上滑块运动的加速度,其测量精度直接依赖于2个光电门之间距离的测量,而在实验中该距离的测量往往不易达到很高的精度,致使加速度的测量精度不高.对计数计时测速仪的电路和单片机程序稍加修改,使之能测出滑块从一个光电门运动到另一个光电门所需时间,就无需测量2个光电门之间的距离,因而提高了加速度的测量精度,节约单片机的资源并缩短运行时间.     

Bi-large Neutrino Mixing See-Saw Mass Matrix with Texture Zeros and Leptogenesis

We study constraints on neutrino properties for a class of bi-large mixing See-Saw mass matrices with texture zeros and with the related Dirac neutrino mass matrix to be proportional to a diagonal matrix of the form diag(ε,1,1). Texture zeros may occur in the light (class a) or in the heavy (class b) neutrino mass matrices. Each of these two classes has 5 different forms which can produce non-trivial three generation mixing with at least one texture zero. We find that two types of texture zero mass matrices in both class a and class b can be consistent with present data on neutrino masses and mixing. None of the neutrinos can have zero masses and the lightest of the light neutrinos has a mass larger than about 0.046 eV for class a and 0.0027 eV for class b. In these models although the CKM CP violating phase vanishes, the non-zero Majorana phases can exist and can play an important role in producing the observed baryon asymmetry in our universe through leptogenesis mechanism. The requirement of producing the observed baryon asymmetry can further distinguish different models and also restrict the See-Saw scale to be in the range of 10¹²～10¹⁵ GeV. We also discuss RG effects on V₁₃.     

混合工质变浓度空调系统动态特性的模拟

本文在分析混合工质变浓度空调系统的传热传质和参数间的相互耦合关系的基础上,以实际流体的质量、动量和能量守恒方程为基础,结合系统各部件的特点,分别建立了各部件的数学模型,并实现了对系统动态特性的模拟计算和分析。     

比较法测试不同颜色匹配函数的性能

为了测试不同颜色匹配函数的预测性能,基于灰色、棕色、紫色和蓝色4个目标色,共制作了16对近同色异谱色样对(围绕每个目标色分别制作了4个待比较色),组织14名年龄不同的色觉正常观察者基于心理物理实验方法中的比较法,开展了色差大小比较实验。结果表明,实验组织的老年观察者的锥细胞响应较年轻观察者有所下降,CIE1931的预测性能优于CIE1964。不同颜色区域,各颜色匹配函数的表现各异,在进行某些颜色(如灰色,紫色和蓝色)区域的色度值表征和色差评估时,即便观察视场角大于4°,CIE1931的计算性能仍然优于CIE1964。现有CIE2006匹配函数考虑到晶状体光谱透光率和中央凹的锥细胞光谱响应,下一步可继续强化中央凹锥细胞光谱响应,优化其计算性能。     

激光推进器概念设计研究现状及发展趋势

 激光推进器技术是激光推进技术的关键技术之一,也是其核心技术,而激光推进器概念设计是开展激光推进器技术研究的首要任务。在对国内外文献综合调研的基础上,总结给出了激光推进器概念设计的研究现状。通过对比分析给出了各种激光推进器构形的优缺点,并就激光推进器概念设计的发展趋势进行了分析讨论。     

Effects of Annealing on Schottky Characteristics in A1GaN/GaN HEMT with Transparent Gate Electrode

A1GaN/GaN heterostructure transistors are promising for power and switching applications. In addition, the transparent wide band-gap A1GaN/GaN heterostructure systems have received considerable attention to transparent electronics. Nowdays, Al-doped ZnO （AZO） thin film plays an increas- ingly important role in various fields of transparent electronics.The AZO-gated A1GaN/GaN HEMT with good dc characteristics and frequency character- istics has been reported. Annealing is widely used to improve the electri- cal characteristics of A1GaN/GaN HEMTs. It is re- ported that the Schottky leakage current can be re- duced by over four orders of magnitude by annealing in an A1GaN/GaN heterostructure with ITO/Ni/Au electrode. Pei et al. reported that the transparency of Ni/ITO gates of A1GaN/GaN HEMTs has been sig- nificantly improved after annealing. However, the evaluation of Schottky C V characteristics was ab- sent. Up to now, few results are reported on the Schot- tky annealing characteristics of AZO in A1GaN/GaN HEMT. Thus the effects of annealing on the leakage current, transparency and interface states character- istics need further study.     

一种实现MSD加法的光学方法

三值光学计算机系统结合光强与光的偏振方向表示三值信息,其核心器件——三值逻辑光学处理器是按照降值设计理论完成的,该处理器能完成所有19683种二元三值逻辑运算.本文旨在提出一种实现加法运算的新方法——用三值逻辑光学处理器实现加法.为了解决加法的串行进位延时问题,使用改良符号数表示进行数据编码,从而实现全并行无进位加法.用三值光学计算机与改良符号数表示相结合的方法实现加法既能够充分发挥三值光学计算机位数巨大的优势以及三值逻辑光学处理器能完成所有二元三值逻辑运算的特性,同时又发挥了改良符号数加法的无进位特点.经实验证明该方法具有可行性和正确性,是实现光学加法器的一种新思路.     

基于自由体积理论及跨接方程的黏度推算模型

结合自由体积理论黏度模型与跨接方程,本文建立了一个适用于从气相到液相且包含临界区在内的黏度推算模型。以水为研究对象,对其对比密度ρ_r(0.01～2.57)、对比温度T_r(0.46～1.12)范围内的黏度进行了计算,计算值与文献实验值的相对偏差绝对平均值为1.81%,近临界区域相对偏差绝对平均值为4.6%。与现有的自由体积理论黏度模型相比,本文建立的黏度推算模型显著提升了近临界区域黏度的计算精度。     

芥菜多糖的研究

采用Sevag法除蛋白和乙醚除脂,再水煮-醇沉法,从芥菜中提取得到浅黄色芥菜粗多糖。苯酚-硫酸法测定总糖含量;UV法及IR法检测多糖性质;自动旋光仪测定旋光度;HPLC鉴定多糖的单糖组分及其相对百分比含量;采用凝胶渗透色谱-激光光散射联用技术(SEC-LLS)分析多糖的分子量范围及其分布。该芥菜多糖,无甜味,易溶于水,总糖含量为98．96%;192 nm处有明显吸收峰,260,280 nm处无吸收峰,证明被测物为多糖,且不含核酸及蛋白质;红外吸收光谱分析,在3 402,2 926,2 853,1 636,1 400,1 385,1 326, 1 125,757,658,619,559 cm-1处表现为典型的多糖吸收峰;旋光度为+151.5°。糖残基间的苷键可能为α-糖苷键;分子量在1.42×104～2.55×106之间,80%的组分集中在2.1×105左右;芥菜多糖主要由葡萄糖、果糖、半乳糖、阿拉伯糖和木糖组成,其摩尔比值为21.4∶12.89∶5.6∶4∶2.5。