基于SPCE061A智能磁性液体表观密度仪控制系统   总被引：2，自引：1，他引：1  

王蔚  李学慧 《实验室研究与探索》2011,30(1)

介绍以SPCE061A单片机为控制器的磁性液体表观密度仪控制系统,用以满足工业设计中复杂的数据采集需要。该系统由SPCE061A单片机控制,通过力敏传感器单元与PC系统通信,设计数据处理方法并编写相应的计算程序和交互式的窗体界面,用户可根据实际测量要求对实测软件进行设置,从而实现对实验数据读取、处理和曲线绘制、显示、打印、保存等功能。同时,用户可远程登录计算机,进入系统设置实测软件,远程进行数据采集,并能得到实时的采集结果,故系统具有扩展性。该系统控制简单、成本低,适用于教学和科研中的数据采集。  相似文献   

Studying children's knowledge base of one-sided levers as force amplifiers     

Miriam Leuchter  Britta Naber 《科学教学研究杂志》2019,56(1):91-112

Attention to core concepts in science and engineering in early education has grown recently, and understanding levers as force amplifiers can be recognized as one of these. Previous studies focused on two-sided levers and do not provide sufficient information about children's knowledge of levers as force amplifiers, nor about their learning and its support from an education perspective. It is important to consider load distance and force distance separately, as may be done in one-sided levers, to understand children's knowledge of levers as “simple machines” thoroughly. Moreover, children's zone of proximal development and the possibilities to foster their knowledge should be explored to understand important features of teaching. We thus directed two studies with 6- to 7-year-old children. In study 1, we conducted a paper-and-pencil test in the context of wheelbarrows (N = 370; age M = 6.62). We investigated whether it is possible to empirically separate the features load, load distance, and force distance as well as to determine their level of difficulty. Our study showed that children's concepts of the three aspects load, load distance, and force distance are fragmented, with children finding it continuously more difficult to judge load, load distance, and force distance correctly. In study 2, we developed a 20-min intervention with a controlled 2 × 2 pre-post follow-up design for exploring the zone of proximal development of 304 6- to 7-year-old children in the domain of one-sided levers as force amplifiers, focusing on force distance and load distance. We implemented a structured learning environment that encouraged the children to manipulate wheelbarrows and supported them with pictures and/or verbal prompts. 6- to 7-year-old children had a higher learning gain when they were exposed to scaffolds that combined pictures and verbal prompts in the posttest as well as in the follow-up test four weeks later compared to the control group.  相似文献   

劳动力价值理论视角下的农民工工资问题探析     

柏娜 《涪陵师范学院学报》2011,27(2):101-104

农民工是我国城乡二元体制下的特有阶层,是农民身份与工人职业的特殊结合。当前农民工工资水平总体偏低且拖欠、克扣现象严重,这与我国劳动力市场上农民工数量供大于求、农民工可接受的工资水平低、组织化程度低相关,为农民工创造公平的就业条件,规范企业用工制度,强化农民工教育、改善维权途径,对维护农民工的合法权益,促进我国的现代化进程及和谐社会的建设有重要的现实意义。  相似文献   

运用内力图规律快速绘制剪力图和弯矩图     

康英杰  夏玉林 《唐山学院学报》2011,24(3):63-64,67

根据荷载集度与剪力、弯矩之间的导数关系,找出了绘制内力图的规律,应用此规律画剪力图和弯矩图不必列内力方程,只需依据梁在不同荷载作用下剪力图及弯矩图的图形特征计算出控制截面的内力值,即能简便、快捷地画出内力图。  相似文献   

论我国农村剩余劳动力的转移     

司晓雪 《巢湖学院学报》2011,13(1):42-45

近几年来,农村劳动力的隐性失业问题日益暴露,并逐渐成为制约中国经济发展的重要因素。实现农村剩余劳动力的有效转移是避免劳动力资源浪费和引发社会问题的重要方面。文章分析了当前我国农村剩余劳动力转移的制约因素,提出了解决问题的对策和建议。  相似文献   

探析电源电动势和内电阻的测定方法和误差     

王志奇 《吕梁高等专科学校学报》2011,1(2)

物理实验在物理教学中占有很大的比例,理解实验原理,探究实验方法,合理分析误差是做好实验的前提,也是学好相应物理内容的关键.电学实验占物理实验的比重较大,其中,电源电动势和内电阻的测定既是电学实验的基础,又是不少学生难以掌握的内容.  相似文献   

民族地区少数民族传统文化变迁及其地理驱动力分析——基于施甸县两个典型布朗族村落的调查与思考     

蔡红燕  赵兴国  罗思远  阿文兴 《保山师专学报》2011,30(1):12-18

在经济、文化全球化和以工业化与城镇化为主要特征的国家发展背景下,面对施甸县布朗族传统文化呈现弱化这一现象,以施甸县两个典型的布朗族村落为研究对象,在运用田野调查、问卷调查及访谈法等方法获取大量研究数据和资料的基础上,采用从定性到定量的综合集成方法揭示施甸布朗族传统文化的变迁特征,并进一步分析其传统文化变迁的地理驱动力,并就如何实现施甸布朗族聚居地区社会经济较快发展与其民族传统文化传承和保护之间的耦合提出相关的对策建议,以期为当地政府制定民族文化发展战略及其传承保护措施提供科学依据和决策参考。  相似文献   

农村劳动力转移培训的个案研究——对“云和师傅”培训的调查分析     

刘超 《职业技术教育》2011,(25)

云和师傅是云和县人民政府建立的具有本地特色的农村劳动力转移就业培训模式。其由云和县农村劳动力素质培训中心统一实施,主要分为后备云和师傅专业技能培训和云和师傅后续素质培训两种,培训领域涉及当地农业生产的多个行业,主要采用本地集中培训的模式。但其在发展过程中也表现出培训结构失调、模式单一、政府过度主导等问题,为此,其在未来发展中应重视对女性及偏远乡镇人口的培训、采用更加灵活的培训模式、增强对政府的监督。  相似文献   

Dynamics and manipulation of ferroelectric domain walls in bismuth ferrite thin films     

Shuyu Xiao  Yaming Jin  Xiaomei Lu  Sang-Wook Cheong  Jiangyu Li  Yang Li  Fengzhen Huang  Jinsong Zhu 《国家科学评论(英文版)》2020,7(2):278

Ferroelectric domain walls differ from domains not only in their crystalline and discrete symmetry, but also in their electronic, magnetic, and mechanical properties. Although domain walls provide a degree of freedom to regulate the physical properties at the nanoscale, the relatively lower controllability prevents their practical applications in nano-devices. In this work, with the advantages of 3D domain configuration detection based on piezoresponse force microscopy, we find that the mobility of three types of domain walls (tail-to-tail, head-to-tail, head-to-head) in (001) BiFeO₃ films varies with the applied electrical field. Under low voltages, head-to-tail domain walls are more mobile than other domain walls, while, under high voltages, tail-to-tail domain walls become rather active and possess relatively long average lengths. This is due to the high nucleation energy and relatively low growth energy for charged domain walls. Finally, we demonstrate the manipulation of domain walls through successive electric writings, resulting in well-aligned conduction paths as designed, paving the way for their application in advanced spintronic, memory and communication nano-devices.  相似文献   

合理使用与许可使用的异同及适用     

刘志刚 《图书馆建设》2005,(5):1-4

版权法自产生之初,就在对版权是保护还是限制这个问题上陷入两难境地。一方面要鼓励和保护优秀作品的创作与传播;另一方面必须出于对社会公共利益的兼顾而对版权人权利加以限制。总的来看,这种限制主要包括合理使用和许可使用两个方面。  相似文献