水与火的故事

"你叫什么?"她把鲜花放入花瓶,腼腆地问. "与火打交道的人!" "你叫火吗?" 他笑而不答. "那我就是水,我要浇灭你这把火!"她甜甜地说. "那咱们可是水火不容,因为火你倒在了7楼,因为你我躺在了医院!"他苦笑.     

2007年高考化学实验试题的新特点及对高考复习的启示

化学实验在2007年高考试题中的体现形式以及解答方式均出现了新的变化;纵观2007年高考化学试卷(含理科综合卷)发现,化学实验试题及分值占的比例较大,全国卷与各省自主命题的试卷各有特点,研究新课改背景下的化学实验教学和实验高考复习无疑是一个新的课题,认真分析高考试题的新特点无疑也是备考复习过程中的重要一环,本文拟结合2007年全国高考试题中化学实验试题来解读化学实验考查的特点及对化学实验备考复习的启示。1试题设计突破常规模式,注重基本实验设计能力的考查例题1(全国Ⅰ)28(15分)水蒸气通过灼热的焦炭后,流出气体的主要成分是C…     

Fragmentation in ^16 O-emulsion interactions at 3.7 A GeV

The topology of ¹⁶O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments,charged secondaries and their dependences on the projectile residues are discussed.     

Electromagnetic dissociation of 3.7 A GeV^16O in nuclear emulsion

The electromagnetic dissociation (ED) of 3.7 A GeV {}^{16}O in nuclear emulsion is investigated with high statistics. It is found that the electromagnetically dissociated cross section increases with increasing beam energy, the charge distribution of projectile fragments is the same as the results at 60 and 200 A GeV, and the production probability of projectile fragments with charge 3≤Z≤5 is less than that of the other projectile fragments. These results can be well explained by use of Weizsacker and Williams method for calculating the ED contributions. The percentile abundance of various decay modes for ED at 3.7 A GeV is close to the result at 60 and 200 A GeV, but it is different from the result at 14.6 A GeV. The ED of 3.7 A GeV is mainly caused by the giant dipole and quadrupole resonance of E1 and E2, which can be qualitatively explained by the multiplicity distribution of projectile proton in ED. The multiplicity distribution of the α fragments in ED and nuclear events have different functional forms. This difference may be a consequence of the different reaction mechanism involved.     

Intermittency in 3.7 A GeV ^16O-emulsion interactions

The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitted in a central rapidity region. The scaled factorial moments, reduced scaled factorial moments and multifractal moments as functions of the bin size in pseudorapidity and in azimuthal angle have been calculated and have revealed the presence of an intermittent behaviour which may be due to the random cascading property of the reaction. The anomalous fractal dimension has been found to increase with the increase of rank of the moment.     

环境工程专业实验室建设与管理初探

高校实验室是进行实验教学和科研的重要基地,是培养学生创新能力和动手能力的重要场所。在教学改革的新形式下,为了让学生在实验室更好的完成实验教学内容,对实验室的建设与管理进行不断的思考与改进成为当务之急。本文从实验室现状、设备及人员管理等方面总结了我校环境工程实验室建设与管理的经验,对实验室建设的现状及存在的问题进行了初步探讨,并对环境工程实验室建设和发展提出了建议。     

对过氧化钠与水反应问题的研究

1.问题的提出 过氧化钠与水反应的实验是中学化学课堂重点演示实验,从目前情况看该实验的研究还有许多亟待解决的问题.特别是过氧化钠与水反应生成氧气质量的理论计算和实验结果的矛盾[1]、过氧化钠与水反应后溶液具有漂白性的原因[2-3]、双线桥标出过氧化钠与水反应过程中电子的得失[4]等疑难问题更为突出,所以从实验和理论上对上述疑难问题加以认真的研究是非常必要的.     

pH试纸在学生分组实验中包装的重新设计

pH试纸是日常化学实验中一种常见的检验溶液酸碱性的试纸,由于操作方便、现象明显,而被广泛使用,但在学生分组实验使用过程中也发现很多问题,因此我们对pH试纸包装进行了重新设计,有关问题如下。1学生分组实验中使用试纸的问题(1)浪费严重,一小块试纸本可以使用多次,但多是剩下     

一种非接触式车辆自动报警系统

设计一种非接触式车辆报警系统。系统基于红外人体热感应原理,传感器接收人体所发射的10um波段附近的红外线,经过信号采集,放大处理,输出控制信息,产生报警信号。传感器安置在汽车的周围,可以对车辆全方位进行监控,适用于特殊车辆的保护。