The Application of Embedded System in NMR Spectrometer Lock System

Homogeneous and stable magnetic field is essential for a high-resolution NMR spectrum, especially one which requires signal averaging or phase cycling. The field-frequency lock technique can effectively improve the long-term stability of the magnetic field. The whole design scheme of the lock system for NMR spectrometer is presented in this paper. The digital control is implemented with Xilinx Virtex-4 FPGA, XC4VFX12-FF668, the signal received from the probe is detected by the quadrature detector, and the resonance frequency drift is locked by the quasi-feedback loops. In the slave computer of the lock system, Wind River's VxWorks real-time operating system is chosen to fulfill the strict requirement for the performance of real-time data acquisition and control, as well as the stability of operation system. Online debugging with the Varian 500MHz spectrometer shows that the lock system achieves the goal of compensating for the intrinsic drift of a superconducting magnet field

Design for Wireless Sensor Network-Based Intelligent Public Transportation System

Intelligent public transportation system is an effective way to improve the quality of our country transportation. Wireless sensor network is a novel technology made by the convergence of sensor technology, micro electro mechanism technology, wireless telecommunication technology and network technology. It is suitable to transportation scenarios for the characteristic of rapidly deployed and self organized. An improved solution combined the wireless sensor network and internet technology is presented in the article. It effectively solves three critical problems of the wireless sensor network, including energy saving, localization and communication distance. By using the low cost and high stability microchip, a high reliability and low cost intelligent public transportation system based on wireless sensor network can be easily established

3D-printed integrative probeheads for magnetic resonance

射频探头前端作为核磁共振设备的核心部件之一，极大程度的决定着系统实验性能的优劣。探头前端通常由射频线圈、射频电路及样品检测管道等部分组成。现有的射频线圈制作技术主要是通过手工或机械手段按照所需的线圈形状进行绕制。但是，当线圈结构较为复杂、不规则，或体积尺寸较小时，常规绕制方法便难以满足结构设计和制造的精度需求，因此造成线圈性能的劣化，增大检测区域的射频场不均匀性，对核磁共振检测产生负面影响。本研究中，利用3D打印熔融沉积制造或光敏树脂选择性固化技术精确加工出一体化磁共振探头前端，使用常温液态金属填充线圈模型管路形成射频线圈，搭建出稳定的一体化磁共振射频探头。利用高精度3D打印和液态金属灌注技术制备出包含有射频线圈和定制化样品管道结构在内的一体化磁共振射频探头前端，克服了传统磁共振三维微型线圈成型困难、与样品腔匹配程度差等问题，提高了探头的信噪比，为定制化的磁共振检测提供了新思路。 该工作由厦门大学电子科学与技术学院陈忠教授、游学秋副研究员和孙惠军高级工程师共同指导完成，博士研究生谢君尧为论文第一作者。厦门大学电子科学与技术学院黄玉清高级工程师、王忻昌副教授、倪祖荣助理教授、硕士研究生张德超，化学化工学院杨朝勇教授、博士研究生李星锐，萨本栋微米纳米科学技术研究院陈宏教授为合作作者。【Abstract】Magnetic resonance (MR) technology has been widely employed in scientific research, clinical diagnosis and geological survey. However, the fabrication of MR radio frequency probeheads still face difficulties in integration, customization and miniaturization. Here, we utilized 3D printing and liquid metal filling techniques to fabricate integrative radio frequency probeheads for MR experiments. The 3D-printed probehead with micrometer precision generally consists of liquid metal coils, customized sample chambers and radio frequency circuit interfaces. We screened different 3D printing materials and optimized the liquid metals by incorporating metal microparticles. The 3D-printed probeheads are capable of performing both routine and nonconventional MR experiments, including in situ electrochemical analysis, in situ reaction monitoring with continues-flow paramagnetic particles and ions separation, and small-sample MR imaging. Due to the flexibility and accuracy of 3D printing techniques, we can accurately obtain complicated coil geometries at the micrometer scale, shortening the fabrication timescale and extending the application scenarios.The work is supported by the National Natural Science Foundation of China (Grants U1632274, 11761141010, U1805261, 11475142, 22073078, and 61801411), and China Postdoctoral Science Foundation (2017M622075).研究工作得到国家自然科学基金、中国博士后科学基金等项目支持

Fine chemicals from cashew nut shell liquid

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Nonequilibrium charge carrier lifetime testing equipment for semiconductor materials by a contactless microwave phase method

Conference Name:2012 3rd International Conference on Advances in Materials and Manufacturing Processes, ICAMMP 2012. Conference Address: Beihai, China. Time:December 22, 2012 - December 23, 2012.University of Wollongong, Australia; Northeastern University, China; University of Science and Technology Beijing; Hong Kong Industrial Technology Research CentreThe accurate measurement of nonequilibrium charge carrier lifetime is of vital significance in research and manufacture of crystalline silicon solar cells. A testing equipment based on a contactless microwave phase method was implemented by being embedded with GPIB, FPGA and a lock-in analyzer. A friendly operation interface was developed, based on the graphic programming language LabVIEW. The virtue of the equipment is achieved by automatic data acquisition and processing, which improves the automatization, efficiency and accuracy of the measurement. ? (2013) Trans Tech Publications, Switzerland

An Integrated Expansion USB Bridge for ISA Data Acquisition Card

Conference Name:2nd International Conference on Anti-Counterfeiting, Security and Indentification. Conference Address: Guiyang, PEOPLES R CHINA. Time:AUG 20-23, 2008.An integrated expansion bus bridge is disclosed that couples the traditional ISA (industry Standard Architecture) data transfer bus to the USB (Universal Serial Bus), which was implemented in the external placement of a ISA data acquisition card. The main transfer function was achieved by the chip of Cypress, EZ-USB AN2131Q, and the performance of the chip, implementation of driver program development, firmware design and application program communication are presented in detail. The advanced performance of USB with Hot Plug In, Plug and Play, easily to expand and engrossing less system resource was shown in the system. Such technology can also be extended efficiently in the field of industry measurement and control, where the ISA bus peripheral card has a wide application