导体杆或导体框碰撞问题解题策略初探

以导体棒或导体框组成的系统,在碰撞瞬间作用持续的时间极短,相互作用力很大,可认为内力远大于外力,因此碰撞过程符合动量守恒定律;在碰撞过程中,如果发生弹性碰撞,碰撞前与碰撞后总动能相等;如果发生非弹性碰撞,系统的总动能减少,因此碰撞过程中系统的总动能不可能增加。

等边三角形导体框匀速旋转的感应电动势推导

一般性推广是中学物理教学中常采用的方法之一。该文结合一道竞赛题,推导出等边三角形导体框匀速旋转的感应电动势与t的函数关系,并讨论其图象与意义,以渗透物理的基本思想,有效地锻炼学生思维能力,培养学生的创造性思维。

Research advances of light-driven hydrogen evolution using polyoxometalate-based catalysts

With the increasing concerns to energy shortage and environmental problems in modern society,the development of cheap,clean,and sustainable energy alternatives has been attracting tremendous attention globally.Among various strategies of renewable energy exploration,solar-driven water splitting into its compositional elements H2 and O2 is an ideal approach to convert and store renewable solar energy into chemical bonds.In recent few decades,as an emerging new type of catalysts,polyoxometalates(POMs)have been widely utilized for water splitting due to their versatile synthetic methodology and highly tunable physicochemical and photochemical properties.This critical review addresses the research advances of light-driven hydrogen evolution using polyoxometalate-based catalysts,including plenary POMs,transition-metal-substituted POMs,POM@MOF composites,and POM-semiconductor hybrids,under UV,near UV and visible light irradiation.In addition,the catalytic mechanism for each reaction system has been thoroughly discussed and summarized.Finally,a comprehensive outlook of this research area is also prospected.

电磁感应计算题的命题设计探析

电磁感应在高中物理中占有重要地位,尤其是电磁感应的力、电、功能综合问题在高考中所占比例高且难度较大。本文从物理模型构建的角度探讨电磁感应与电路、动力学及功能三方面结合的可能命题方向并归类剖析。