自制低成本电荷相互作用仪器

验证"同种电荷互相排斥,异种电荷互相吸引"的实验是初中物理电学的重要实验。但受南方气候条件限制,实验效果有时并不理想。笔者通过长期教学积累和反复实验,探索出了利用饮料吸管、乒乓球等材料制作"电荷相互作用仪器"。该方法在课堂上应用于学生自主探究,教学效果很好。     

论放松技术对短跑训练的意义

短跑放松技术是当代短跑技术的重要特征之一.运动员的良好放松能力在训练和比赛中能充分挖掘运动潜力和发挥运动技术水平,从理论上阐述了短跑放松技术在短跑中的作用、影响因素及训练方法.     

畲族在宋代的形成及其分布地域

本文认为，畲族以“畲”、“斜”、“Zhuo”等方言中的同音同义通假字作为族称，始于南宋嘉定中，比一般认为的始于宋末早的半个世纪。至迟到南宋中期，畲族作为一个独立民族的诸多要素俱已成熟，所以畲族的形成时间不晚于南宋中叶。当时畲族的分布范围相当广阔，以赣闽粤边的潮、梅、循、汀、漳、赣为中心，西及于粤北，东北有向闽西北、赣东北、浙西南推进的态势。客家与福佬两个民系的中间地带，大致也是畲族的分布区。至于畲族史诗与许多族谱把潮州凤凰山作为祖居地、发祥地，那只是畲族形成和保持民族凝聚力的一个文化符号。     

从贾府的女人们看曹雪芹的女性观——《红楼梦》人物论

赞赏女性的才干,关注女性的命运,同情女人的不幸遭遇,是曹雪芹女性观的核心。提倡自主婚姻,倡导以共同理想为基础的婚恋观是曹雪芹反对男尊女卑,抨击封建礼教的基本观点。《红楼梦》通过无数女性的悲惨命运,呼唤女性觉醒,期盼女性个性解放。     

赢得卓越——体验企业教练技术

沉思:时代需要什么样的企业? 稍稍留意一下改革开放几十年中国企业的发展历程,不难发现这样一条规律:抛开国有企业、集体企业不谈,八十年代是谁敢办企业,谁就能够挣钱、发财,不管其文化水平、社会地位、人生阅历,也不管是城里人还是农村人;九十年代做企业就不那么容易了,只要投资就能赚钱已成为不可能,这个时期所能生     

论历史教学的课堂语言要求

语言表达是教师的一项基本功。历史教学中教师的课堂语言,必须讲求科学性并做到形象生动,还要感情充沛,语言简练、干净、明确。     

语言生成过程中的艺术品性--对卡西尔语言生成论的一种解读

构成语言的基本单位之一是名称，名称最早产生于直觉的聚合。在人类的神话阶段，人们对神的崇拜实质上是对神的名称的崇拜，因为各种神灵的本质只是一种只有能指而没有所指的虚构。早期人类意识中的隐喻思维对名称的产生起了关键的作用。所以，语言生成的初始过程不是一个逻辑化的过程，而是一个诗性思维的过程。     

比较教育研究的基本范式述评

本文根据历史线索对比较教育研究领域中的三种范式：科学主义的研究范式、批判理论的研究范式和解释学的研究范式，进行了大致的厘定和评价，试图展示该领域理论形态和研究策略的整体景观。同时，就各自理论话语所处的特定语境作简单的分析，并倡导各自间不应是相互对峙与攻讦，而是要彼此间抱宽容和理解态度，不是苛求于整合而是要寻求互补。     

Header error control schemes for coping with upstream channel noise in the HFC network

The Hybrid Fiber-Coax (HFC) network is being paid close attention to in recent years as a bi-directional broadband access network. To achieve seamless connection with the backbone network, and Asynchronous Transfer Mode (ATM) Network Network Interface (NNI) cell format is used as the basic transmission packet unit in the HFC system. As the transmission condition of the HFC system’s upstream channel is bad, two improved header error control (HEC) schemes, i. e. the improved HEC and the cell interleaving technique, are employed to guarantee the packet integrity. Theoretical analysis of the results showed that the improved HEC and the cell interleaving technique are applicable to isolated random errors and burst errors, respectively.     

Event triggering power sharing control for AC/DC microgrids based on P -F droop curve method

The power sharing of AC/DC micro-grids is researched in this paper. The proposed strategy mainly include two parts: the primary power event triggering control with secondary control and an adaptive quasi sliding mode voltage control in inner-loop. Firstly, a event triggering power sharing control (ETPSC) based on $P?F$ droop curve is developed to regulate the voltage and frequency of AC and voltage of DC with the aim of the proportional power sharing between AC and DC micro-grids. The triggered threshold of ETPSC can be chosen to decide the transmitted power between AC and DC micro-grids. When the difference power between AC and DC micro-grids is less than the triggered threshold of power flow, there is no power sharing between AC and DC micro-grids, which can less the number of switching the power flow direction and the transmitted line power loss. The ETPSC has a great robust for the disturbances of load and improve the stability of the system. An adaptive quasi-sliding-mode control,which is implemented easily and flexibly with small computational burden and only based on input/output (I/O) measurement data but not the model any more, is used to control voltage in inner-loop. The effectiveness of the proposed control schemes is demonstrated by some numerical simulations and experimental results.