运用教材插图提高复习效率

正高中物理教材中配有大量的插图,其中包含丰富的物理知识.复习过程中,笔者从教材中的两幅插图出发,挖掘图中特点,总结其中规律,既复习了有关知识,又培养了学生的多种能力.不仅摆脱了题海战术,而且提高了学生的积极性,收到了良好的教学效果.一、知识归纳图1、图2分别是等量异种点电荷的电场线和等势面分布图,其特点如下:1.场强、电势特点1两电荷连线上:中点场强最小(但不等于零),关于中点     

例谈等温线时空间变化规律及分析方法

一、原理再现（一）气温水平分布的一般规律1．无论南北半球,气温一般是由低纬度向高纬度递减,等温线数值一般是由低纬度向高纬度递减。     

针叶林里的吸血“魔鬼”

伏尔加格勒理工学院的两名实习生哈桑和库罗到达了渺无人烟的西伯利亚东北部,进行探险考察。根据携带的北冰洋沿岸地形分布图,两个人深入到了一处狭窄的半岛区域。这里处处都生长着遮天蔽日的原始针叶林树,     

换一种方式来读图——初中地理分布图阅读教学策略

回答有关位置的问题是这门叫做地理的学科的重要特点之一。(美/普雷斯顿·詹姆斯语)位置与分布是地理课程标准中表述区域地理内容标准的基本维度。用象征符号把地理事物的位置与分布呈现出来,即地理分布图。初中地理分布图包括专题地图与区域地图两类,前者多出现于地理总论部分,后     

求理想气体任意过程中温度的最值

求理想气体任意过程中温度的最值问题,是热学竞赛题中一个重要的问题,在解析这些问题时,必须清楚等温线的特点,必须把图像的方程与理想气体状态方程结合,必须清楚一元二次方程的特点．现举例如下：     

Bayesian mapping of neural tube defects prevalence in Heshun County, Shanxi Province, China during 1998-2001

Objective： To estimate the prevalence rates of neural tube defects （NTDs） in Heshun County, Shanxi Province, China by Bayesian smoothing technique. Methods： A total of 80 infants in the study area who were diagnosed with NTDs were analyzed. Two mapping techniques were then used. Firstly, the GIS software ArcGIS was used to map the crude prevalence rates. Secondly, the data were smoothed by the method of empirical Bayes estimation. Results： The classical statistical approach produced an extremely dishomogeneous map, while the Bayesian map was much smoother and more interpretable. The maps produced by the Bayesian technique indicate the tendency of villages in the southeastern region to produce higher prevalence or risk values. Conclusions： The Bayesian smoothing technique addresses the issue of heterogeneity in the population at risk and it is therefore recommended for use in explorative mapping of birth defects. This approach provides procedures to identify spatial health risk levels and assists in generating hypothesis that will be investigated in further detail.