管道中CaO颗粒吸收CO2的格子Boltzmann方法模拟

采用格子Boltzmann方法对多孔CaO颗粒与CO₂之间的气固反应过程进行模拟.主要研究在二维矩形截面管道中雷诺数(Re)和孔隙率对单个CaO颗粒吸收CO₂效率的影响.结果表明:增大Re会相应提高CaO颗粒吸收CO₂气体的效率.同时对于同一Re,CaO颗粒吸收CO₂气体的效率随其孔隙率呈非线性变化,这是由于不同孔隙率颗粒固体量和渗透率存在差别因而影响化学反应的速率.     

Required width of exit to avoid the faster-is-slower effect in highly competitive evacuation

A group of competitive people escaping through an exit could lead to the formation of a deadlock, which significantly increases the evacuation time. Such a phenomenon is called the faster-is-slower effect(FIS) and it has been experimentally verified in different systems of particles flowing through an opening. In this paper, the numerical simulation based on discrete element method(DEM) is adopted to study a group of highly competitive people through an exit of varying widths. The FIS effect is observed for a narrow exit whilst it is not observed for the exit wide enough to accommodate two people through it side-by-side. Experimental validation of such a phenomenon with humans is difficult due to ethical issues. The mouse is a kind of self-driven and soft-body creature and it exhibits selfish behaviour under stressed conditions.Particles flowing through an opening in different systems, such as pedestrian flow, animal flow, silo flow, etc. have similar characteristics. Therefore, experimental study is conducted by driving mice to escape through an exit of different widths at varying levels of stimulus. The escape time through a narrow exit(i.e., 2 cm) increases obviously with the increase of stimulus level but it is quite opposite to a wider exit(i.e., 4 cm). The FIS effect is avoided for an exit wide enough to accommodate two mice passing through it side-by-side. The study illustrates that FIF effect could be effectively prevented for an exit when its width is twice the size of particles.     

A numerical study of contact force in competitive evacuation

Crowd force by the pushing or crushing of people has resulted in a number of accidents in recent decades. The aftermath investigations have shown that the physical interaction of a highly competitive crowd could produce dangerous pressure up to 4500 N/m, which leads to compressive asphyxia or even death. In this paper, a numerical model based on discrete element method(DEM) as referenced from granular flow was proposed to model the evacuation process of a group of highly competitive people, in which the movement of people follows Newton's second law and the body deformation due to compression follows Hertz contact model. The study shows that the clogs occur periodically and flow rate fluctuates greatly if all people strive to pass through a narrow exit at high enough desired velocity. Two types of contact forces acting on people are studied. The first one, i.e., vector contact force, accounts for the movement of the people following Newton's second law. The second one, i.e., scale contact force, accounts for the physical deformation of the human body following the contact law. Simulation shows that the forces chain in crowd flow is turbulent and fragile. A few narrow zones with intense forces are observed in the force field, which is similar to the strain localization observed in granular flow. The force acting on a person could be as high as 4500 N due to force localization, which may be the root cause of compressive asphyxia of people in many crowd incidents.     

关于亚纯函数的0-1-∞集（英）

Let {an}, {bn} and {pn} be three disjoint sequences with no finite limit points. If it is possible to construct a meromorphic function N in the plane whose zeros, one points and poles are exactly {an}, {bn} and {pn} respectively, where their multiplicities are taken into consideration, then the given triple ({an}, {bn}, {Pn}) is called the zero-one-pole set (of N). In general an arbitrary triad ({an}, {bn}, {pn}) is not a zero-one-pole set of any meromorphic function. This was proved by Rubel and Yang[6] explicitly for entire functions. Ozawa[5] proved the following.     

攀矿铁精矿矿浆品位的原位EDXRF分析试验

铁精矿矿浆品位原位EDXRF(能量色散X射线荧光)分析试验在攀钢选矿厂进行,矿浆中水与矿粉体积比在2/5~2/1之间,在(L×W×H=8×2×20cm)的沉淀条件下,经过9 min自然沉淀,静态测量(60 s);从测量结果看出:仪器分析周期约10 min,与化学分析结果的绝对误差小于0.3%,并说明铁精矿矿浆品位在线分析完全可行,这为开发新型在线铁精矿矿浆品位的EDXRF分析仪器提供了依据。     

微阵列芯片的荧光光漂白特性

微阵列技术为大量基因表达水平的同时监控提供了一种高效的手段。随着微阵列芯片朝着小型化、高通量和弱信号方向发展,荧光检测技术以其易寻址和高灵敏度等优势越来越受到世人关注。在微阵列技术中,人们通过检测微阵列芯片上不同位置斑点的荧光信号强度,可以得知微阵列芯片不同位置固定的已知序列探针与荧光染料标记的cDNA样品的杂交情况。对一张微阵列芯片多次扫描后,荧光染料发生光漂白,荧光强度发生衰减变化,它将为微阵列的数据分析带来误差。使用荧光浓度梯度微阵列芯片研究了芯片经多次扫描后荧光斑点强度的衰减情况,通过拟合相同荧光斑点经多次重复扫描后得到的信号强度,得到了荧光斑点强度按指数形式衰减的规律,并在此基础上研究了荧光斑点强度衰减指数模型中的参数与荧光斑点初始浓度的关系,为进行微阵列芯片数据光漂白误差修正提供了实验依据。     

牛磺酸缩邻香草醛席夫碱铜配合物[Cu(C_(12)H_8N_2)(C_(10)H_(11)NO_5S)]·3.5H_2O的合成及晶体结构

含硫席夫碱及其金属配合物具有抑菌、抗癌和抗病毒的生物活性[1-3],有些含O、N席夫碱金属配合物具有仿酶催化活性[4].而氨基酸席夫碱配合物具有良好的生理活性,近年来得到人们的普遍重视[5,6].2-氨基乙磺酸(牛磺酸)作为生物     

水溶液中碳纳米管的表面增强拉曼光谱研究

合成了碳纳米管和金纳米颗粒的复合物, 测量了水溶液相中复合物的表面增强拉曼光谱, 结果表明, 碳纳米管的巯基化修饰可以提高碳纳米管与金纳米颗粒复合的效率, 随着金纳米颗粒负载量的增加, 碳纳米管的拉曼信号逐渐增强. 加入己二胺分子可以减小金纳米颗粒之间的距离使表面增强效应更显著, 碳纳米管的拉曼光谱得到进一步的增强. 还可进一步在复合体系中加入对巯基苯胺和罗丹明B等小分子拉曼探针, 利用金纳米颗粒的表面增强效应, 这种多元复合体系有望作为多通道拉曼成像探针材料.     

在无机化学教学中增加纳米化学内容的实践与探讨

简单介绍了在无机化学教学中增加纳米化学内容的重要性和意义,并对如何在无机化学教学中引入纳米化学内容进行了实践和初探。     

微波快速合成4A分子筛过程中镧复盐的作用

微波快速合成4A分子筛过程中镧复盐的作用;4A分子筛;硫酸镧硫酸钠复盐;微波合成