基于PICmicro系列单片机的超声波测距仪设计     

安长俊  周家婕 《科教文汇》2011,(22):104-104,106

利用微处理机控制单元（MCU microprocessor control unit）控制的超声波测距仪系统,由PIC16F877单片机、超声波发射电路、超声波接收放大电路及显示电路组成。通过MCU控制时间计数,计算超声波自发射至接收的往返时间,从而得到实测距离。此系统具有易控制、工作可靠、测距准确度高和流程清晰等优点。  相似文献   

Ideal type-II Weyl points in topological circuits     

Rujiang Li  Bo Lv  Huibin Tao  Jinhui Shi  Yidong Chong  Baile Zhang  Hongsheng Chen 《国家科学评论(英文版)》2021,8(7)

Weyl points (WPs), nodal degenerate points in three-dimensional (3D) momentum space, are said to be ‘ideal’ if they are symmetry-related and well-separated, and reside at the same energy and far from nontopological bands. Although type-II WPs have unique spectral characteristics compared with type-I counterparts, ideal type-II WPs have not yet been reported because of a lack of an experimental platform with enough flexibility to produce strongly tilted dispersion bands. Here, we experimentally realize a topological circuit that hosts only topological bands with a minimal number of four ideal type-II WPs. By stacking two-dimensional (2D) layers of inductor-capacitor (LC) resonator dimers with the broken parity inversion symmetry (P), we achieve a strongly tilted band structure with two group velocities in the same direction, and topological surface states in an incomplete bandgap. Our results establish an ideal system for the further study of Weyl physics and other exotic topological phenomena.  相似文献   

卡诺图在数字逻辑电路教学中的应用     

李霞 《大众科技》2013,(8):114-115,90

文章通过具体实例的验证,对卡诺图在数字逻辑电路教学中的典型应用进行总结概括,系统地掌握卡诺图的应用可以使学生在学习过程中达到事半功倍的效果。  相似文献   

数字电路课程探究式教学模式的探索与实践     

李飚 《科教文汇》2013,(24):73-74

文章对传统教学模式和探究式教学模式的优劣进行深入分析,指出引进探究武教学模式的必要性,再以教学实践经验为依据提出要保证探究式教学能够顺利施行,教师必须梳理课程知识脉络,精选能够覆盖整个课程的探究任务,并指出数字电路课程的探究式教学可分解为11个核心探究任务来开展,最后给出了组合逻辑电路的设计这一探究任务的探究式教学的思路、方法及过程。本文的教改实践可作为高校其他课程开展探究式教学的方法借鉴。  相似文献   

电子线路设计-Protel99 SE的学习和应用     

罗芬 《大众科技》2012,14(3):218-219

文章对电子线路计算机辅助设计软件Protel99SE的学习和应用进行了较详细的阐述,对Protel99 SE的重要性和功能进行了介绍。  相似文献   

Non-physical approaches to counteract age-related functional deterioration: Applications for rehabilitation and neural mechanisms     

Uros Marusic  Sidney Grosprêtre 《European Journal of Sport Science》2018,18(5):639-649

Normal and pathological ageing are associated with several motor impairments that reduce quality of life and represent a general challenge for public healthcare systems. Consequently, over the past decades, many scientists and physiotherapists dedicated their research to the development and improvement of safe and costless methods to counteract the progressive decline of motor functions with age. The urgency of finding new and easy to implement methods is even more paramount in case of acute pathologies (e.g. stroke or hip surgery). The frailty of older population makes it difficult or even impossible to use traditional physical therapy at an early stage after the occurrence of a pathology. To that purpose, non-physical approaches such as cognitive training (e.g. memory, attention training) and mental techniques (e.g. motor imagery) have grown in popularity for the elderly. Such methods, involving individual and/or group exercises, have shown particular effects on increasing or maintaining cognitive functions, as well as physical performances. Improving the motor function (especially in older age) requires an improvement of motor execution, i.e. the pathway from the brain motor areas to the muscle but also higher cognitive control. The present work reviews different non-physical interventions that can be used as a complementary approach by asymptomatic or frail older adults, and the effects thereof on functional performance. The use of cognitive training or motor imagery protocols is recommended when physical practice is limited or not possible. Finally, insights into the underlying neurophysiological mechanisms are proposed.  相似文献   

我国产业政策法律化研究——以软件产业与集成电路产业发展立法为视角   总被引：1，自引：0，他引：1  

丁道勤 《中国软科学》2007,(8):35-45

软件产业与集成电路产业是信息产业的核心,在高新技术产业发展中占有特殊地位。我国颁行18号文件等产业政策对产业发展起到了重要促进作用。但随着形势的不断发展,特别是中美集成电路增值税争端,使得18号文件等产业政策越来越不适应产业发展的要求。本文结合产业政策法的内涵和特点,提出产业政策法应包括实质意义上和形式意义上的产业政策法两大方面,认为我国当前亟待加快立法。将此类产业政策上升到法律的高度,为产业发展创造稳定的、可预期的法制环境。  相似文献   

Molecular authentication of geo-authentic Scrophularia ningpoensis     

Chen C  Duan LN  Zhou XL  Chen BL  Fu CX 《Journal of Zhejiang University. Science. B》2011,12(5):393-398

Scrophularia ningpoensis has long been used in the Chinese Materia Medica for inflammation. Like other herbal medicines, S. ningpoensis collected from different localities may considerably differ in their therapeutic efficacy, and the one grown in Zhejiang Province is recognized as geo-authentic. However, it is difficult to confirm the geographical authenticity by similar morphological characteristics. In the present study, inter-simple sequence repeat (ISSR) markers were conducted to detect S. ningpoensis from different origins. A 1 259-bp fragment amplified by primer UBC874 was found only in geo-authentic ones. By cloning and sequencing that specific band, sequence characterized amplified region (SCAR) markers were designed to distinguish geo-authentic S. ningpoensis from others. This is a rapid and easy method that can be used to identify the geographical authenticity of S. ningpoensis.  相似文献   

基于并联开关技术的低电压FnMOS数字电路开关级设计     

姚茂群  蒋征科  黄志存  陈华华  沈继忠 《科技通报》2003,19(3):217-221

在分析了采用低电压工作时数字电路性能下降甚至不能正常工作的原因后，提出了两种适合于低电压nMOS电路设计的串联开关转换成并联开关技术，并从开关级具体设计了低电压三值nMOS电路．对设计的电路进行模拟得到的结果表明，在采用标准工艺参数时，只要工作电压不低于管子阈值，则本文设计的低电压电路不仅具有正确的逻辑功能，而且具有较快的速度．  相似文献   

模拟电路与高频电路课程整合教学探讨   总被引：1，自引：0，他引：1  

陈桂兰  余红娟  廖任秀 《中国科技信息》2008,(5):211-212

结合高职教育特点,提出了将模拟电路和高频电路整合为一门电子线路课程的必要性、可行性和整合思路,并对如何提高整合效果提出了几点看法和意见。  相似文献