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神经网络用于风洞中压气机失速监控
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作者 丁凯峰 《试飞研究》 2001年第2期32-34,共3页
旋转失速和喘振是严重影响轴流压气机性能的截然不同的两种气动不稳定现象。旋转失速和喘振均能引起转子和静子叶片振动及压气机内部温度急剧上升,在叶片上的大的动应力会引起严惩的机械破坏。对16英尺超音速风洞试验中压气机的3C3转... 旋转失速和喘振是严重影响轴流压气机性能的截然不同的两种气动不稳定现象。旋转失速和喘振均能引起转子和静子叶片振动及压气机内部温度急剧上升,在叶片上的大的动应力会引起严惩的机械破坏。对16英尺超音速风洞试验中压气机的3C3转子叶片,失速发生约10转(即1秒)后,失速产生的振动应力将达到对压气机产生机械危害的程度。旋转失速是16英尺跨音速风洞试验中C-1压气机中常见的不稳定现象;旋转失速在2转(0.2秒)时间内,产生一个应力峰值并逐渐衰减。显然,需要一个系统在出现失速征兆的瞬间能很快探测到并发出警告,该系统还具有自主修正能力。建立在多年实践观察基础上的开环技术已成为当前主要的监控模式,工程师可以采修正的操作以避免压气机进入失速。在控制系统中引入闭环防失速装置可使压气机工作点离开失速边界是人们最终的追求目标。实现对压气机失速的控制需要对开环和闭环模式的高速自动处理。神经网络用于数据分类、信号处理、对象建模及预测的一项新的信息处理技术。由于神经网络用于数据分类具有快速、精确及高抗噪性,因而,神经网络适合被选作对压气机不稳定性进行探测及监控研究。 展开更多
关键词 神经网络 超音速风洞试验 压力机失速 监控 开封技术 不稳定性 旋转失速
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Analysis of Discharge Spark Energy in Buck Converter of a Continuous Mode of Inductive Current 被引量:1
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作者 CUI Bao-chun CHENG Hong WANG Cong LU Huan-yu SHI Yun 《Journal of China University of Mining and Technology》 EI 2006年第4期514-517,522,共5页
The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of int... The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM — continuous conduction mode) and dis- crete inductance current (DCM — discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maxi- mum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power. 展开更多
关键词 Buck converter discharge spark intrinsically safe
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特种防伪纸板已获国家专利
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作者 郑咸雅 《造纸化学品》 CAS 2005年第2期72-72,共1页
河南省开封市天剑防伪技术研究所经过多年的探索,最近成功研制出一种新型的具有防伪功能的纸板。
关键词 开封市天剑防伪技术研究所 防伪功能 纸板 图文标识
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Multichip on Aluminum Metal Plate Technology for High Power LED Packaging
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作者 Choong-mo NAM Mi-hee JI 《Journal of Measurement Science and Instrumentation》 CAS 2010年第3期297-299,共3页
Multichip on Ahnnintnn Metal Plate(MOAMP) technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode(LED) p-n junction and LED lighting module to ... Multichip on Ahnnintnn Metal Plate(MOAMP) technology with simple structure and low thermal resistance is developed for effective heat reratrval of Light Emitting Diode(LED) p-n junction and LED lighting module to have high reliability. The thermal resistance of LED modules was numerical and experimental. Thermal resistance from the jtnction to aluminten metal plate, considering input power of IFD module using MOAMP technology, is 3.02 K/W, 3.23 K/W for the measured and calculated, respectively. We expect that the reported MOAMP technology with low thermal resistance will be a promising solution for high power LED fighting modules. 展开更多
关键词 - thermal resistance Light Emitting Diode (IFO) aluminum metal plate IHOAMP
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