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.     

Monte Carlo study for γ+N→π+N at a new compound target

An inbuilt compound target composed of carbon and tungsten is designed, and optimized by realistic GEANT4 Monte Carlo simulation. Also, we do a Monte Carlo study for single-pion photoproduction at the target. The results are presented from the simulation of pion yield, angular distribution and spectrum (at θ_lab, θ_cm=41°). These efforts are important to the coming measurement of the differential cross section for γ+N→π+N.     

“原子-分子”论的创立及其对我们的启迪

“原子-分子”论在近代化学史上是一项划时代的成就,它的创立过程是在曲折中前进的。道尔顿的原子论为科学的“原子-分子”论奠定了基石,揭开了近代化学新时期的序幕。道尔顿与盖.吕萨克的学术争论主要是围绕道尔顿原子论自身存在的内在矛盾及其外化的“半个原子”问题而展开的,它构成了近代“原子-分子”论创立过程中的一个重要环节。阿伏加德罗在道尔顿原子论基础上提出的分子学说,初步解决了道尔顿原子论的内在矛盾及其外化的“半个原子”问题,使科学的“原子-分子”论趋于完善。坎尼扎罗“原子-分子”论的最终确立,是道尔顿原子论与阿伏加德罗分子学说有机整合的结果。“原子-分子”论的这一创立过程给予我们的启迪是深刻的,它展示了科学理论的曲折发展、“继承-创新”辩证发展、内在矛盾动力、内在矛盾外化等发展规律。     

磁能活性水的生物效应研究

我们用动物实验研究了磁处理的磁能活化水的生物效应.这个磁能活化水是用4400Gs的磁场处理后得到的.在磁能活化水对高血脂Wister大鼠的血常规指标、血液流变学指标、血液生化指标、肝组织中有关自由基代谢的生化指标以及老鼠的脾脏系数的影响的研究中发现,在高脂饲料的喂养下实验组大鼠的胆固醇含量明显低于对照组大鼠,同时实验组大鼠的体重增重也明显小于对照组大鼠,说明磁能活化水有一定的降血脂的能力.同时,在血液流变学的指标测定中看出实验组大鼠的高切粘度明显低于对照组的,说明饮用磁能活化水的大鼠的红细胞变形性要好于饮用普通水的大鼠.