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31761.具有单辅助开关的谐振直流环节逆变器
[计算机、通信和其他电子设备制造业] [2014-12-23]
为实现一种结构简单、控制方便、高效率、高功率密度的逆变器,提出了一种新型谐振直流环节软开关逆变器的拓扑结构.通过在传统硬开关逆变器的直流环节添加辅助谐振单元,使直流母线电压周期性地归零,可以实现逆变桥主开关器件的零电压开关,而且辅助开关器件可以实现零电流开通和零电压关断.此外,其辅助谐振单元只有一个辅助开关器件,所以该逆变器控制相对简单,硬件成本低.对其工作原理进行分析,给出不同工作模式下的等效电路图和软开关的实现条件.制作一个1k W的实验样机,通过实验结果验证该软开关逆变器的有效性.
关键词：谐振；零电压开关；单辅助开关；软开关；逆变器
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31762.全球SOFC市场报告（2015-2019年）
[化学原料和化学制品制造业,电力、热力、燃气及水生产和供应业,计算机、通信和其他电子设备制造业] [2014-12-22]
An SOFC is a device that generates electricity through an electrochemical process that involves oxidation of electrolytes when placed between two electrodes - anode and cathode. Fuel cells are generally categorized based on the type of electrolyte material used in them; an SOFC uses a solid oxide or ceramic electrolyte. Some of the advantages of an SOFC include low cost, low emissions, long-term stability, high efficiency, and fuel flexibility. Its high fuel flexibility permits the use of cheap, safe, and readily available fuels such as hydrocarbons, natural gas, hydrogen, methanol, and syngas. An SOFC, however, requires a high operating temperature, usually within the range of 932 degrees Fahrenheit to 1,832 degrees Fahrenheit, for the activation of ceramics. This high operating temperature leads to mechanical and chemical compatibility issues and longer start-up times.
关键词：SOFC；电化学过程；产生电力设备；电解质
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31763.全球防空反导雷达市场报告（2014-2018年）
[信息传输、软件和信息技术服务业,计算机、通信和其他电子设备制造业] [2014-12-20]
Radar is an object detection system that makes use of radio waves to ascertain the range altitude, direction, and speed of approaching and still objects. It is used to detect missiles, spacecraft, ships, aircraft, weather formations, and terrain. It is used as an early-warning device to spot an enemy's airborne systems and approaching missiles from great distances, and for surveillance, ground control interceptions, and long-range early warnings. It is mainly used by defense establishments.
关键词：雷达；物体检测系统；线电波；早期警告装置；机载系统；导弹逼近
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31764.全球电梯和自动扶梯市场报告（2014-2018年）
[计算机、通信和其他电子设备制造业,电气机械和器材制造业] [2014-12-20]
Elevators are a type of transport system that facilitate the vertical transit of people and goods within a building's premises. Escalators are moving staircases that are mainly used for transporting people between the different floors of buildings. People depend on elevators and escalators in various places such as airports, office buildings, malls, residential complexes, schools, and railway stations.
关键词：电梯；运输系统；中转垂直；自动扶梯
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31765.数据：10月中国移动4G用户突破5000万
[信息传输、软件和信息技术服务业,计算机、通信和其他电子设备制造业] [2014-12-17]
关键词：中国移动；4G
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31766.全球化学传感器市场报告（2015-2019年）
[化学原料和化学制品制造业,计算机、通信和其他电子设备制造业] [2014-12-16]
Chemical sensors convert chemical signals into electrical signals and transfer these through transducers incorporated in a sensitive layer. These sensors help analyze the chemical composition of a sample, which is either in a liquid or gas form.
关键词：化学；传感器；接收器；动力学
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31767.全球3D打印机市场报告（2015-2019年）
[计算机、通信和其他电子设备制造业] [2014-12-16]
3D printing, also known as AM, is the process of making a 3D model, using digital data by manufacturing (printing) it layer by layer, using a 3D printing material.
关键词：3D打印机；市场分析
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31768.全球听力设备市场报告（2015-2019年）
[计算机、通信和其他电子设备制造业,专用设备制造业] [2014-12-16]
Audiological devices are used to treat people with hearing loss, balance disorders, and earrelated problems.
关键词：听力设备；市场分析；助听
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31769.全球企业制造智能市场报告（2014-2018年）
[信息传输、软件和信息技术服务业,计算机、通信和其他电子设备制造业] [2014-12-10]
EMI is a framework of software networks that delivers real-time information about the manufacturing processes. This framework helps in the collection, reporting, analysis, presentation, and synchronization of data between enterprise-level and plant floor systems.
关键词：企业；制造智能；EMI
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31770.全球电子书市场报告（2015-2019年）
[计算机、通信和其他电子设备制造业,信息传输、软件和信息技术服务业] [2014-12-10]
E-books are books available in a digital format, which allows readers to access content anywhere and at any time using their handheld devices. The Global E-book market is the fastest growing segment in the Global Book Publishing industry.
关键词：电子书；数字格式；手持设备
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