共查询到20条相似文献,搜索用时 62 毫秒
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针对航空装备故障预测需求,在对灰色GM(1,1)基本模型分析研究的基础上,通过引入弱化算子对该故障预测模型进行改进,并以某直升机滑油温度控制盒峰值电压数据为对象进行应用分析,结果表明弱化算子改进模型可降低故障预测误差、提高预测精度;同时,将基于弱化算子改进模型的算法分别与序列平均变化率算子、新陈代谢模型两种算法进行组合,也验证了基于弱化算子改进模型可以提高预测精度,这对提高航空装备故障预判与维修保障能力具有重要参考借鉴价值。 相似文献
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环氧模塑封材料的热-机械疲劳失效分析 总被引:2,自引:0,他引:2
封装材料的热疲劳失效是封装器件失效的主要原因之一。对在微电子封装中应用很广的环氧模塑封装材料进行了常温和高温下的拉伸、疲劳实验。基于以疲劳模量作为损伤因子的疲劳寿命预测模型,相应的材料参数通过实验获得。并通过实验得出了该环氧模塑封装材料考虑温度影响的疲劳寿命预测模型,利用该模型可以对微电子封装用高聚物的疲劳寿命进行预测。 相似文献
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基于相关向量机的剩余寿命预测方法,核函数是影响相关向量机模型预测性能的重要因素.目前的相关向量机预测模型以单核为主,且核函数的选择存在较大主观性,导致所构建的预测模型性能有限.本文提出一种融合多个核函数构建相关向量机预测模型的方法,通过果蝇算法优化多个核函数优化组合的线性方程系数,提高了模型的预测性能,并将该方法应用于预测锂离子电池的循环剩余寿命.分别采用美国NASA和马里兰大学的电池退化数据集,对本文的方法进行了实验验证.实验结果表明:多核相关向量机预测方法的平均绝对误差和均方根误差都小于最优的单核相关向量机预测方法. 相似文献
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靶场测控装备的管控与状态预测对于确保靶场试验任务的顺利开展有着重要的意义,也是状态/故障处理研究领域的发展方向。结合装备结构关系网络,通过对状态信号的分析,给出了靶场测控设备单元的状态预测方法。依据电子元器件寿命规律,结合状态异常出现的分布函数,重点构建了离散型状态变量的预测模型,提出了相应的预测流程和方法。仿真计算表明,提出的状态及故障预测模型和方法有效,可为提高任务期间装备的可靠性提供判断依据。 相似文献
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建立了Elman神经网络模型来实现绝缘栅双极型晶体管(IGBT)的寿命预测。分析了IGBT的结构及其失效原因,结合NASA埃姆斯中心的加速热老化试验数据,确定了以集电极-发射极关断电压尖峰峰值作为失效预测依据。利用高斯滤波的方法对试验数据进行预处理,构建了单、多隐层Elman神经网络寿命预测模型,并构建了广义回归神经网络(GRNN)寿命预测模型作为对比模型。采用均方误差、平均绝对误差、最大相对误差作为各模型预测性能的评估指标。结果表明,提出的Elman神经网络模型比GRNN模型有更好的预测效果。二隐层的Elman神经网络模型均方误差为0.202 0%,平均绝对误差为0.387 6%,最大相对误差为3.023 0%,可以更好地实现IGBT寿命的预测。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test. 相似文献
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The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high. 相似文献
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The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation. 相似文献
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Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's. 相似文献
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In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line(w), the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line(x), the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines(y), the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line(z) in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line(q) in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution(λ/△ 2) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy. 相似文献
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High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center. 相似文献
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This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献