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低场磁共振系统的低噪声前置放大器研究设计 被引量:3
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作者 亢科 徐雅洁 +1 位作者 张闻文 杨晓冬 《波谱学杂志》 CAS CSCD 北大核心 2017年第3期383-395,共13页
噪声前置放大器是磁共振射频接收子系统中的重要组件,它的性能优劣直接决定了最终磁共振图像的好坏.目前市场上的低噪声前置放大器大多基于中高场磁共振系统开发,而针对低场磁共振系统的很少;另外,商用低场磁共振系统的低噪声前置放大... 噪声前置放大器是磁共振射频接收子系统中的重要组件,它的性能优劣直接决定了最终磁共振图像的好坏.目前市场上的低噪声前置放大器大多基于中高场磁共振系统开发,而针对低场磁共振系统的很少;另外,商用低场磁共振系统的低噪声前置放大器价格相对较贵,并且多采用两级放大结构,结构复杂、调试难度大、成本相对较高.在此背景下,针对0.5 T低场磁共振设备利用Keysight公司的先进设计系统(ADS)软件对低噪声前置放大器进行研究设计,采用一级放大结构,探索电路设计与布局对放大器性能的影响.实测结果表明自主设计的低噪声前置放大器在21 MHz共振频率附近噪声系数为0.5 dB左右,增益达到了30 dB,能够满足低场磁共振应用的要求. 展开更多
关键词 磁共振系统 噪声 高增益 前置放大器
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低场磁共振在膝关节创伤中的应用价值 被引量:1
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作者 王小康 潘玉才 《中国临床研究》 CAS 2014年第8期987-989,共3页
目的分析膝关节创伤的MRI表现,探讨低场MRI的诊断价值。方法回顾性分析46例膝关节创伤患者的低场MRI资料。结果骨损伤36例,其中骨折伴骨挫伤12例,隐匿性骨折伴骨挫伤3例,单纯性骨挫伤21例;软骨损伤34例,其中软骨表面光滑26例,表面凹凸不... 目的分析膝关节创伤的MRI表现,探讨低场MRI的诊断价值。方法回顾性分析46例膝关节创伤患者的低场MRI资料。结果骨损伤36例,其中骨折伴骨挫伤12例,隐匿性骨折伴骨挫伤3例,单纯性骨挫伤21例;软骨损伤34例,其中软骨表面光滑26例,表面凹凸不平8例;半月板损伤29例34个,其中I级损伤11个,Ⅱ级损伤14个,Ⅲ级损伤9个;韧带损伤25例35根,其中部分撕裂29根,完全撕裂6根;关节积液46例。结论低场MRI是一种全面的诊断检查技术,在膝关节创伤中具有重要的临床应用价值。 展开更多
关键词 磁共振成像 低场系统 膝关节 创伤 诊断
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Landslide Monitoring Using Low Cost GNSS Equipment - Experiences from Two Alpine Testing Sites 被引量:2
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作者 Otto Heunecke Jessica Glabsch Stefan Schuhback 《Journal of Civil Engineering and Architecture》 2011年第8期661-669,共9页
Simple GNSS navigation receivers, developed for the mass market, can be used for positioning with sub centimeter accuracy in a wireless sensor network if the read-out of the carrier phase data is possible and all data... Simple GNSS navigation receivers, developed for the mass market, can be used for positioning with sub centimeter accuracy in a wireless sensor network if the read-out of the carrier phase data is possible and all data is permanently broadcast to a central computer for near real time processing of the respective base lines. Experiences gained in two research projects related to landslide monitoring are depicted in terms of quality and reliability of the results by the developed approach. As far as possible a modular system set up with commercial off-the-shelf components, e.g., standard WLAN fur commtmication, solar batteries with solar panels for autarkic power supply and in cooperation of existing proofed program tools is chosen. The challenge of the still ongoing development is to have a flexible and robust GNSS based sensor network available - concerned not only for landslide monitoring in future. 展开更多
关键词 Early warning systems geo sensor networks low cost precise differential GNSS near real time processing.
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Verification of Drainage Sterilization System Uses Low-Voltage Pulsed Electric Field in a Prawn Farm
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作者 Hirotaka Naitou Yukinori Tani Shingo Nishi 《Journal of Agricultural Science and Technology(A)》 2014年第3期189-196,共8页
It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn (Penaeus monodon) aquaculture, diseases caused by viruses such as white spot syndrome ... It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn (Penaeus monodon) aquaculture, diseases caused by viruses such as white spot syndrome virus (WSSV) and bacteria such as Vibrio have become a menace. Appropriate treatments of prawn culture pond's waters are advocated for preventing and controlling pathogens. The purpose of this study was to conduct an antimicrobial water treatment using a low-voltage pulsed electric field sterilization. Here we prepared a mechanical low-voltage pulsed electric field system with copper wire coiling around a titanium ring. The viability of WSSV in seawater was examined by prawn infectivity experiments. We inoculated healthy prawns (approximately 10-15 g) with the WSSV master sample that passed 0-3 times through the system. WSSV infection in prawns decreased according to the number of passes through the system. Healthy prawns survived for〉 10 days without feeding, where as prawns inoculated with the WSSV master sample showed symptoms of white spot and died in about 4 days. Two-thirds of the prawns inoculated with the WSSV master sample that was passed once through the system developed WSSV symptoms and were polymerase chain reaction (PCR) positive. However, no symptoms were observed and prawns were PCR negative when the WSSV master sample was passed three times through the system. Based on these results, we purpose that a low-voltage pulsed electric field system will serve as an efficient pond drainage sterilization system and will replace conventional treatments using chemicals such as sodium hypochlorite. 展开更多
关键词 Low-voltage pulsed electric field sterilization prawn farm Penaeus monodon white spot syndrome virus SoutheastAsia.
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