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Search Results: 1 - 10 of 15352 matches for " 易子馗 "
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一种基于心理声学品质和调制频率的车窗电机检测方法
A method of window motor detection based on psychological acoustic??quality and modulation frequency

,谭建平
- , 2018,
Abstract: 为保证车窗电机出厂前声品质和性能达到要求,提出了基于心理声学参量和调制频率的车窗电机检测方法。基于传统的心理学客观参量模型计算正常电机和故障电机声音样本的响度、粗糙度、尖锐度,基于修正的模型计算其尖锐度值,并通过主客观评价试验分析正常电机和故障电机的响度、粗糙度、尖锐度、修正后尖锐度与主观感受反映的相关性;以响度、修正后尖锐度作为特征向量,将电机分为正常电机和异常噪声电机,在此基础上为了诊断异常噪声电机的故障类型,加入物理参量调制频率作为预测车窗电机故障类型的特征量;最后,构建附加动量法优化的BP神经网络分类器对电机进行分类,通过试验验证优化的神经网络分类器。研究结果表明:正常电机与故障电机的响度和修正后尖锐度值存在明显差别,响度和修正后尖锐度与人的主观心理一致性较好,一致性系数达0.8以上;碳刷?不幌蚱魅毕莸牡缁?噪声频率在80~100 Hz,蜗杆?渤萋秩毕莸牡缁?噪声频率在20~40 Hz,而正常电机的噪声频率在100 Hz以上,调制频率可作为检测电机故障类型的特征量;优化的神经网络分类器对车窗电机的分类准确率达90%以上,且与传统BP神经网络分类器相比其准确率更高和耗时更少。
In order to ensure the sound quality and performance of the window motor before leaving the factory, the method of window motor detection based on the psychoacoustic parameters and modulation frequency was put forward. Based on the traditional psychology objective model of, the loudness, roughness and sharpness of the sound samples of the normal motor and fault motor were calculated. The sharpness was calculated based on the modified model,and the correlation between the loudness, roughness, sharpness, corrected sharpness and subjective perception of the normal motor and fault motor was analyzed through subjective and objective evaluation experiments. The motor was divided into normal motor and abnormal noise motor by using the loudness and corrected sharpness as feature vectors. On this basis, the modulation frequency of physical parameters was added as the characteristic quantity to predict the fault type of the vehicle window motor in order to diagnose the fault type of the abnormal noise motor. Finally, the BP neural network classifier optimized by the additional momentum method was constructed to classify the motor, and the optimized neural network classifier was verified by experiments. The results show that there are obvious differences between the loudness and the corrected sharpness of the normal motor and fault motor. The loudness and corrected sharpness have good consistency with people??s subjective psychology, and the consistency coefficient is more than 0.8. The frequency of motor noise of carbon brush??commutator defect is 80 to 100 Hz, the motor noise of worm??gear defect is 20 to 40 Hz, while the noise of normal motor is above 100 Hz. The modulation frequency can be used as the characteristic quantity to detect the fault type of motor. The classification accuracy of the optimized neural network classifier for vehicle window motor is more than 90%, and it has higher accuracy and less time consumption compared with the traditional BP neural network classifier. 5 tabs, 10 figs, 20 refs
全国第一届生物力学学术会议

力学与实践 , 1982,
Abstract: 由中国力学学会和中国生物医学工程学会联合召开的我国第一届生物力学学术会议已于1981年7月20日至7月23日在上海举行。参加会议的约有80单位的156名代表。交流了74篇学术论文。这次学术会议是这个非常年轻的力学分支学科的第一次全国性盛会。三年前,中国力学学会刚成立生物力学专业组时,全国只有几个零星的研究小组。
全国第一届生物力学学术会议

力学与实践 , 1982, DOI: 10.6052/1000-0992-1982-023
Abstract: 由中国力学学会和中国生物医学工程学会联合召开的我国第一届生物力学学术会议已于1981年7月20日至7月23日在上海举行。参加会议的约有80单位的156名代表。交流了74篇学术论文。这次学术会议是这个非常年轻的力学分支学科的第一次全国性盛会。三年前,中国力学学会刚成立生物力学专业组时,全国只有几个零星的研究小组。
咸宁市血吸虫病综合防治效果分析
,
中国热带医学 , 2012,
Abstract:
美、苏两国有关欧洲集体安全问题的交锋(1954-1957)

华东师范大学学报(哲学社会科学版) , 2015, DOI: 10、16382/j.cnki.1000-5579.2015.03.008
Abstract: 1954年2月10日柏林四国外长会议上苏联首次正式提出有关建立欧洲集体安全体系的建议,使欧洲集体安全问题成为了当时人们关注的焦点问题之一,直至1958年美苏在柏林问题上的再次紧张而走向平息。根据有关档案研究发现,美苏两国在这一问题存在着根本性的分歧,苏联打算通过建立欧洲集体安全体系,“绕开”东西方争执已久的德国问题,保持欧洲和德国的分裂现状,巩固苏联在欧洲的势力范围和对东欧的控制,实现阻止联邦德国加入北约、削弱西方联盟、将美国排除在欧洲之外等目标;美国则主张先让德国在自由选举的基础上完成统一后再考虑欧洲集体安全问题,而且统一后的德国必须加入北约,反对因建立所谓欧洲集体安全而削弱西方阵营的实力。双方的分歧使美苏双方在柏林四国外长会议以及随后的会议上在建立欧洲集体安全的议题上都无法达成共识。究其原因在于,一是美苏两国都没有真正打算放弃以实力为基础的抗衡政策;二是双方在德国问题上的分歧导致美苏双方在欧洲集体安全问题上难以形成一致,特别是在德国问题和欧洲集体安全问题的解决顺序上观点完全不同。
基于全局优装法的共轴光学系统装调研究
建,广威
- , 2018,
Abstract: 以共轴光学系统中圆柱形零件圆环形装配平面为研究对象,研究了装调中多零件对接时基准轴的角偏误差传递与补偿原理.首先分析了共轴光学系统的实际装调方法和典型定中心基准轴传递路径.然后基于误差测量和最小二乘法,确定拟合圆环形装配平面方程.运用几何变换理论得到精确描述单个零件底面和顶面的角偏误差的变换矩阵,以及两零件装配时结合面上两坐标系间的变换矩阵,建立了多零件装配时始末法线角偏误差与相对装入角度的显式函数关系.针对不同类型的定中心基准轴传递路径,采用不同的遗传算法方案实现了对始末法线角的优化,提出了求解相对装入角度允许误差的方法.最后提出了一种基于全局优装法的共轴光学系统装调方法,并以某共轴光学系统为例,验证了本文方法的可行性与实用性.
Taking the ring assembly plane of cylinder part of coaxial optical system as the research object, the principle of tilt error transfer and compensation of fiducial axis in the case of multiple parts assembling was studied. Firstly, optical alignment of coaxial optical system and typical centering fiducial axis transfer paths were analyzed. And then error measurement and Least Square Method were conducted to fit the ring assembly plane of cylinder part and to get the coefficients of least-squares plane equation. By the theory of 3D geometry transformation, the transformation matrices precisely describing the tilt error of bottom face and top face in a single part, the transformation matrices of two coordinate systems of assembly joint surface in the case of two parts assembling and the function relationship between the angle between two Normal Lines of Initial Bottom Surface and End Top Surface (ANLIBSETS) and the Relative Load Angle (RLA) in the case of multiple parts assembling were established. Aiming at different types of centering fiducial axis transfer paths and applying different genetic algorithm plans, the optimization of ANLIBSETS was achieved. The method of solving the error of RLA was proposed. Finally, an optical alignment method of coaxial optical system based on global optimization alignment method was proposed. The feasibility and practicability of this method are verified by an example of a coaxial optical system.
一种超低功耗模数转换器的设计与仿真
An Ultra-Low Power SAR ADC with C-2C Capacitor Array DAC

胡云峰 川 李琛 周国富
- , 2017,
Abstract: 为了降低电子终端设备的功耗,文中提出了一种基于C-2C电容阵列DAC的超低功耗SAR ADC。首先,通过使用C-2C电容和三电平转换方案,文中的电容阵列DAC转换能耗相比传统结构降低99.41%,面积减少87.2%。接着,采用基于动态逻辑的逐次逼近寄存器(SAR)和两级全动态比较降低SAR ADC整体功耗。最后,SAR ADC在180nm CMOS工艺下进行设计与仿真。仿真结果表明:在1V电源电压,100kS/s的采样频率下,ADC的信噪失真比(SNDR)为61.59dB,有效位(ENOB)为9.93位,总功耗为0.188μW,品质因素(FOM)值为1.9fJ/Conv.-step。文中设计的超低功耗SAR ADC适用于低功耗电子终端设备。
: In order to reduce the power consumption of electronic devices, an ultra-low power SAR ADC with C-2C capacitor array DAC is presented. Firstly, by using C-2C capacitor and tri-level switching scheme, the proposed capacitor array DAC achieves 99.41% switching energy saving and 87.2% capacitor area reduction, compare to conventional switching scheme. Next, dynamic logic SAR and two-stage fully dynamic comparator are used to decrease the power consumption of SAR ADC. Finally, the proposed SAR ADC is implemented in 180 nm CMOS technology with 1 V supply. The simulation results show that, at sampling rate of 100kS/s, the ADC achieves an SNDR of 61.59dB and ENOB of 9.93bits, consumes 0.188μW, resulting in a Figure-of-Merit(FOM) of 1.9 fJ/conversion-step. In conclusion, the ultra-low power SAR ADC proposed in this paper is suitable for application in low power electronic devices
层结切变流中的rossby波的稳定度
谭本
气象学报 , 1990, DOI: 10.11676/qxxb1990.059
Abstract: rossby波的稳定度问题是大气动力学的中心问题之一,这方面的研究工作已有很多。早期,文献[1-4,9]采用标准波型法对此问题作了开创性的研究,得到了许多重要结论。如,有关不稳定的判据,稳定波和不稳定波的结构,以及它们对维持大气环流所起的作用等。
大气rossby波动力学的研究进展
谭本
气象学报 , 2008, DOI: 10.11676/qxxb2008.079
Abstract: rossby波是旋转大气和海洋中的一类重要波动,在天气和气候演变中起有重要的作用。该文介绍了北半球中纬度地区的两类重要rossby波——斜压不稳定波和准定常行星波,在最近20余年来取得的一些重要研究进展。文中涉及的主要研究领域有:斜压不稳定波包动力学、湿斜压过程对斜压不稳定波的作用、北半球风暴轴动力学、斜压波包与高影响天气的预报、准定常行星波的形成机理、准定常行星波的水平传播与能量频散、准定常行星波的垂直传播与能量频散、三维准定常行星波的传播与能量频散。
烃基硅铜酸盐与2-芳基-2-环烯酮1,4-加成反应的立体选择性及2-取代-3-硅基环烷酮的合成有机化学
,平贵,刘汉文a
有机化学 , 2008,
Abstract: 研究了烷基苯基硅铜酸盐与2-环烯酮的1,4-加成反应的立体选择性,并合成了一系列新的2-取代-3-硅基环烷酮.结果表明,在0℃下用饱和NH4Cl溶液处理,烷基苯基硅铜酸盐与2-芳基-2-环烯酮的1,4-加成反应的立体选择性不同程度地受芳基和环的大小影响,得到顺、反两种产物;并首次发现室温下用甲醇处理反应时,其立体选择性不受或者很少受环大小、芳基的性质以及与硅原子相连的取代基的影响,只得到反式产物.芳基溴甲烷与由烷基苯基硅铜酸盐与2-环烯酮1,4-加成所得的烯醇盐反应时,只得到反式产物.合成产物的结构用IR,1HNMR,13CNMR,MS和HRMS等进行了表征.
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