清华屏蔽实验反应堆中子注量率能谱的调节和测量

叙述了采用多种屏蔽过滤方法,通过实验获得多种条件下的中子注量率能谱的调节和测量。     

Isotopic water dilution technique in body fluid measurement in some domestic animal species

Dilution procedures using tritiated water and Evans blue dye (T 1824) were applied to estimate total body water and plasma volume in small ruminants, pigs and cockerels during the two different seasons in Zimbabwe. The amounts of total body water (TBW) obtained were between 60% to 85% of the body weight in sheep and goats, 40% to 60% in pigs and 63% to 75% in cockerels. TBW values were significantly higher (P < 0.05) in the small ruminants than in pigs and observed age differences were significant (P < 0.05) in the small ruminants. There were significant (P < 0.05) seasonal differences in the total body water mean values but nonsignificant (P > 0.05) differences in the plasma volume mean values for the domestic species investigated.     

Molecular characterization of erythrocyte glucose-6-phosphate dehydrogenase deficiency in Al-Ain District, United Arab Emirates

Operational skills involved in controlling a motor vehicle were measured in two groups of very healthy elderly drivers and a young control group to test the hypothesis that there are age-related declines in operational performance that may influence driver safety. An actual behind-the-wheel, standardized road test was employed using a motor vehicle equipped with sensors to record speed, braking activity, and lane position, as well as direction and magnitude of front-wheel and eye-movement excursions. The data from these sensors were used as dependent measures of operational performance. Older drivers made fewer steering and eye-movement excursions and drifted across the center line more frequently than the young control group. Younger drivers drove significantly faster and executed more braking applications than did their older counterparts. The motor-vehicle operational performance of older healthy drivers was related to visual-spatial attentional declines and the useful field of vision associated with the normal aging process.     

THE VAPOR PRESSURES OF ANTIMONY IN LIQUID CALLIUM-ANTIMONY ALLOYSS

采用气流输运法测定了720,750及780℃时液态纯Sb及Ga-Sb合金中组分Sb的蒸气压。由蒸气压的实验数据和Ga-Sb系的T-X相图构成了Ga-Sb系中Sb蒸气压的P-T图。     

通用突变控制方法及其在潜艇中的应用

运用非线性动力学和突变理论,研究了高维系统建立具有理想特性突变的控制方法.引入冲失滤波器保证系统平衡点不变,并利用隐式判据、中心流形定理以及规范形法确定控制增益.以潜艇空间运动为例,阐述计算的全过程.该控制方法简便、快捷,可广泛应用到实际控制系统的设计中.     

1-乙基-3-甲基咪唑四氟硼酸盐离子液体结构性质的模拟计算

离子液体以其独特的性质广受关注,被称为"绿色设计者溶剂",人们对其潜在的应用价值做了大量的研究.实验采用HyperChem软件构建了1-乙基-3-甲基咪唑四氟硼酸盐([EMIM][BF4])离子液体分子结构的3D模型,并用PM3法进行预优化,然后应用Gaussian 03w程序分别在RHF/6.31G(d)和BLYP/6-31G(d)计算水平上进行量子化学计算,并经振动频率和强度分析得到理论红外谱图.结果表明,[EMIM][BF4]离子液体的阴阳离子存在着氢键等弱相互作用.     

超空泡航行体纵向运动的鲁棒极点配置控制

由于空泡及滑行力的存在,使得超空泡航行体的建模及控制问题变得非常复杂,在其模型简化过程中会产生一定的建模误差,采用鲁棒极点配置算法进行超空泡航行体控制可以有效克服这一缺点.对超空泡航行体所受的流体动力、尤其是滑行力的动态特性进行了分析整理;建立了超空泡航行体纵平面内的动力学模型;最后利用鲁棒极点配置算法设计了控制器.仿真结果表明,该控制系统具有较强的鲁棒性及稳定性.对各控制变量的控制效果进行了对比分析,分析结果表明空化器比尾舵具有更好的控制效果.     

将硬件引入“面向对象程序设计”课程实验教学

针对“面向对象程序设计”课程实验内容的设置容易使学生产生学之无用的思想及学后不会用的问题,结合电子信息专业培养特色,压缩了传统的、基本的实验内容,增加了应用性强的实验项目,并将硬件引入实验教学。实践表明,改进后的实验教学模式效果良好。