CFD simulation of micro-particle trapping under water tweezers

In early research, capture and manipulation of particles were mainly achieved by means of light, electricity and plasma in micro-fabficaton and micro-assembly. A new method is proposed using micro-water jet to form water tweezers to capture solid particles and implement position control of micro-particles. This paper analyzes the basic prin- ciple of water tweezers, and the discrete element method and smoothed particle hydrodynamics method are employed to establish a solid-liquid coupling model used in analyzing the trapping mechanism. A flow field model is set up to simulate dynamic characteristic of water tweezers based on computa- tional fluid dynamics （CFD）. Selection of boundary conditions, initial guess, solver control and convergence strategies of the model are discussed. Velocity and pressure of streamline are predicted and discussed under certain input conditions. Simu- lation results demonstrate that it is an efficiently theoretical method to eventually trap solid particles by water tweezers.     

HIGH SCHOOL STUDENTS’ PROFICIENCY AND CONFIDENCE LEVELS IN DISPLAYING THEIR UNDERSTANDING OF BASIC ELECTROLYSIS CONCEPTS

This study was conducted with 330 Form 4 (grade 10) students (aged 15??C?16?years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students?? understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess students?? confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of students?? responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45?% of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts.     

提升网络学术期刊传播能力的实践与思考

为提升网络学术期刊的传播能力,提高网络学术期刊的发行质量,针对网络学术期刊的特点,围绕其发行与传播环境,并结合对2015年我国SCI收录期刊的实证分析,提出提升网络学术期刊传播能力的对策。网络学术期刊传播能力的提升,需要编辑树立互联网思维,需要建立健全多渠道的发行途径,重视标识符的使用以及重视挖掘语义出版等新出版模式。学术期刊的发展应顺应时代潮流,新元素和新出版模式的使用将成为网络学术期刊发展的必然趋势。     

大学生焦虑状况的调查分析

大学生的焦虑情绪是一个不可忽视的问题,主要采用问卷调查法,采用了心理健康自评量表SCL-90,对某大学的240名大学生进行了随机抽样调查。对调查数据从年级、性别和学科三个方面做了统计分析,统计结果表明:各个年级的学生出现了不同程度的焦虑。针对学生的焦虑问题提出了建设性的措施。     

景帝朱祁钰易立太子案

明景帝在于谦等大臣的辅佐下,获得了北京保卫战的巨大胜利后,将太上皇英宗迎回来,安置并囚禁于南宫,并采取各项措施,使得比他只大一岁的太上皇不得与外界有任何联系,以防止其复辟。与此同时,他产生了将自己的儿子立为皇太子的念头,因为在他的前面,已经有过明成祖朱棣推翻建文帝后将自己的儿子立为太子之事。为了实施这一意图,他进行了一系列工作,不择手段,乃至动用武力,贿     

对运动补剂的探讨

运动补剂是专门为参加体育运动的人而研制的保健食品，目前主要有饮料和各种口服液或冲剂等补品。运动后应根据运动时消耗和代谢紊乱的特点进补，不能和体弱或某些疾疾虚症时一样进补。运动员进补尤其要有科学性。在运动补剂的研制中要尽快采用生物工程技术，提高补剂的强壮效果。     

动漫中的暴力类型分析——对596名初中生的调查

随着动漫产品的逐渐成人化,青少年群体开始成为动漫消费的主要群体.为了解广泛传播中的动漫暴力内容分布,本研究选取了596名初中生,对他们喜爱的动漫中的暴力状况进行调查,结果发现:暴力内容为主的动漫占初中生喜爱的动漫节目的六成左右;男生更喜爱高暴力动漫;随着年级的增高,初中生越来越喜爱高暴力动漫.     

基于问题解决的《计算机应用基础》课的教学思考

结合作者多年的《计算机应用基础》课的教学经验,探讨"研究性学习 上机操作"的教学模式,通过解决实际问题,调动起学生学习的积极性、能动性、创造性,提高了学习效率,对学生综合能力的培养有很大好处。     

线性代数的几何化与应用化教学探讨

本文研究了结合解析几何与实际案例进行线性代数教学的重要性及实质內涵.探讨了具体的实施方案,针对改革现状提供了合理化建议,并分别进行了举例说明.