ADS无窗散裂靶件水模拟实验研究

散裂靶件作为加速器和次临界堆芯的耦合部件,是ADS系统相关研究最主要的组成部分之一。无窗靶巧妙地利用了液体的自由液面特性,避免了质子束对结构材料直接轰击,是一种很有前景的散裂靶靶件形式。采用水作为实验工质搭建了一套无窗散裂靶水模拟实验台架,该实验系统覆盖了无窗散裂靶水模拟实验所需的流量及压力条件,采用粒子图像测速仪(PIV) 对自由界面的流场进行可视化观察与分析,得到了自由界面的基本表征参数之间关系和可视化界面的流场信息。结果表明,无窗靶自由液面的位置和形状受到回路整体流量、压力和靶件几何尺寸的影响。As the coupling component between accelerator and subcritical core, the spallation target is of crucial importance to the operation safety of the whole system. Hence, the spallation target is one of the most important parts in ADS corresponding researches. Due to lifetime limitation of material, the windowless target which has a stable free surface attracts more and more attention. The present paper deals with the experimental investigation on the free surface behavior in an approximately 1:1 size windowless target model using water as test fluid. We can get the flow and pressure conditions of windowless spallation target water simulation experiment from the platform. The free surface and eld visualization were obtained by particle imaging velocimetry. The  results show that the position and  flow pattern of the free surface depend on experimental pressure, flow velocity and geometry of the target.     

随机数与模拟实验

在统计与概率学习中,最有效的教学途径是通过学生亲身实践、动手模拟,来体会统计思想和概率的意义．随机模拟试验需要大量随机数,用手工方法费时费力,而图形计算器可以快捷便利地实现,笔者以HP图形计算器为例,探讨利用图形计算器进行随机数与模拟实验教学的问题．     

温室效应模拟实验装置

根据温室效应的产生原理设计制作了温室效应模拟实验装置.装置由温室、模拟地面、模拟太阳、温室保温层以及隔热水槽等部分组成.用数字温度计来测定温室温度变化值.当HFC-134a(四氟乙烷)当作与空气对比的温室气体时,在25～30 min内出现了0.5～0.6℃的温差,在1 h出现了约1℃的温差.该装置具有使用方便、实验操作简单、实验现象明显等特点,能够较好地展示温室效应现象.     

“大型(兆瓦级)风力机的空气动力学问题”专刊预告

近年来,风能作为无污染、可再生的自然能源引起了人们的高度重视。风力机是捕获风能的动力装置。大型(兆瓦级)风力机的建造和运行涉及到一系列复杂的空气动力学理论和应用问题:如叶片翼型升力特性、叶片气动弹性和气动噪声、风力机风洞模拟实验以及叶片气动优化设计等,成为近期国内外力学、工程界研究的前沿和热点之一。     

植物药抑制泌尿系结石形成的化学基础

植物药治疗泌尿系结石具有独特的疗效.本文综述了国内外植物药(泽泻,Phyllanthus niruri,Zeamays,Agropyron repens和Herniaria hirsute等)在体外模拟实验和动物实验中对泌尿系结石形成的影响,植物药抑制泌尿系结石形成的机制和化学基础是:植物药与钙离子发生配位,降低尿石盐的过饱和度;抑制一水草酸钙生长,诱导二水草酸钙形成;抑制晶体生长和聚集;可以保护尿路粘膜,防止晶体在肾上皮细胞上发生粘附;改变尿石形成促进剂和抑制剂的排泄量.     

Effect of Vibration on Water Transport through Carbon Nanotubes

We study the response of water permeation properties through a carbon nanotube on the time-dependent mechanical signals. It is found that there is a critical frequency of vibrating fc （about 1333 GHz） which plays a significant role in the water permeation properties. The total water flow, the net flux, the number of hydrogen bonds and the dipole flipping frequency of the single-file water chain inside the nanotube are almost unchanged for the frequency of vibrating f 〈 fc. Simulation results show that the nanotube can be effectively resistant to the mechanical noise. Such excellent effect of noise screening is attributed to the exceptional property of water molecules connected by strong hydrogen bonds with each other and forming a one-dimensional water chain inside the nanotube. Our findings are important for the understanding of why biological systems can achieve accurate information transfer in an environment full of fluctuations.