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…     

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     

考查双基 重视综合 体现创新——2002年高考理科综合能力测试化学试题浅析及几点启示

本文浅析 2 0 0 2年高考化学试题的特点 :考查双基、重视综合、体现创新。总体上说今年化学试题难度适中 ,与去年相比难度有所增加。从结构上看 ,虽然今年化学的知识点覆盖面要比去年广 ,增加了去年没考到的电解质溶液和物质结构 ,但是试题不完全拘泥于教学大纲。计算量比去年大且主要体现学科内综合 ,更强调学生的思维过程 ,突出考查学生的素质与能力 ,并体现创新意识的培养。     

对能对弹核碎裂反应截面的影响

运用改进的量子分子动力学(ImQMD)模型嫁接GEMINI统计衰变模型对400 AMeV 36Ar与C、Al、Cu、Pb的弹核碎裂反应截面的奇偶效应进行了理论分析。分析结果表明，弹核碎裂电荷反应截面的奇偶效应产生在初级碎块的退激发过程中，而且退激发过程中的对能在奇偶效应的产生中起着重要作用。如果不考虑对能，弹核碎裂电荷反应截面的奇偶效应将消失。同时由于对能的作用使得弹核碎裂的中子反应截面也表现出明显的奇偶效应。     

The fragmentation of 20Ne at 400 A MeV

The total charge-changing cross sections and partial cross sections for the production of projectile fragments are measured in the interactions of 400 A MeV ²⁰Ne with aluminum, carbon and polyethylene targets sandwiched with CR-39 plastic nuclear track detectors. The measured total charge-changing cross sections are compared with the predictions using the Bradt-Peters semi-empirical formula, and the NUCFRAG2 and PHITS models. It is shown that the measured experimental results are in good agreement with the theoretical model prediction and other experimental results, and it can be clearly seen that the partial cross sections for fragment production show obvious odd-even effects.     

Projectile fragment emission in the fragmentation of ~(56)Fe on C,Al and CH_2 targets at 471 A MeV

The emission angle and the transverse momentum distributions of projectile fragments produced in the fragmentation of ⁵⁶Fe on CH₂, C and Al targets at 471 A MeV are measured. It is found that for the same target, the average value and width of the angular distribution decrease with an increase of the projectile fragment charge; for the same projectile fragment, the average value of the distribution increases and the width of the distribution decreases with increasing the target charge number. The transverse momentum distribution of a projectile fragment can be explained by a single Gaussian distribution and the averaged transverse momentum per nucleon decreases with the increase of the charge of projectile fragment. The cumulated squared transverse momentum distribution of a projectile fragment can be explained well by a single Rayleigh distribution. The temperature parameter of the emission source of the projectile fragment, calculated from the cumulated squared transverse momentum distribution, decreases with the increase of the size of the projectile fragment.     

Forward-backward multiplicity correlations 4.5 A GeV/c ^16O-emulsion interactions

A detailed study of the mechanisms of the emissions of pions and protons in the forward and backward hemispheres in 4.5 A GeV/c oxygen-emulsion interactions has been carried out. The correlations between the multiplicities of secondary charged particles in the backward and forward hemispheres are investigated.     

3.7A GeV 16O-Em作用中的间歇行为

对3.7A GeV ¹⁶O-Em作用产生的慢粒子标度阶乘矩分布进行研究, 得出间歇指数随矩阶数的增加而增加, 随靶核质量的增加而减小; 反常分形维数 随q的增加而增加; 对于每一个q值, d_q随平均多重数的增加而减小, 表明在3.7A GeV ¹⁶O-Em作用中多粒子产生具有自相似级联的性质.     

Intermittent type fluctuation of target fragments produced in 16O-AgBr interactions at 4.5 AGeV/c

A study of intermittency of target associated fragments produced in the interactions of ¹⁶O-AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F_q, has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variable χ(z) suggested by Bialas and Gazdzicki. The anomalous dimensions, d_q, increase linearly with the order of moments, q. This observation indicates the association of multifractility with production mechanism of target associated fragments.     

兴趣与数学教育

教师提高数学教学质量离不开启发学生学习数学的积极性。如何调动学生学习积极性已成为数学教学研究的紧迫课题。调动学习积极性可以通过学习目的教育,培养兴趣,竞赛、奖励等种种途径。兴趣是诱发学习动机的有效办法。然而,兴趣曾经被看作是低级趣味,培养兴趣则被说成不突出政治。