共查询到20条相似文献,搜索用时 62 毫秒
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针对无线电能传输存在的频率分裂现象以及效率低的问题,文中以双侧LCLC补偿拓扑结构的电场耦合型传能系统作为研究对象,通过系统建模分析易变参数对系统输出的影响规律。利用电路理论推导出系统效率与重要参数之间的关系式,运用MATLAB仿真软件对系统效率进行详细的分析,并采用实验验证了仿真结果的正确性。结果表明,将耦合机构的电容值调到频分点以下可以避免系统出现频率分裂,而固定耦合极板的相对位置,通过把系统的频率调大到效率关键点,可以提高系统效率,系统的最佳效率可达89.4%。 相似文献
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为了研究大气激光通信中单模光纤耦合接收效率起伏概率分布特性,建立了受大气湍流扰动的瞬态耦合效率计算模型,据此得出影响光纤耦合效率统计分布的最少无量纲参数.通过研究发现:随着孔径半径-大气相干长度比的增大,耦合效率逐渐减小;随着耦合几何参数的增大,耦合效率先增大后减小,在某一点取得最大值.通过对空间光到单模光纤的瞬态耦合效率进行蒙特卡罗模拟与分布特征分析,提出使用双Johnson SB;分布来拟合瞬态耦合效率的概率密度函数,并用实验测量数据进行了验证.研究结果可以为不同大气湍流条件下的空间光到单模光纤耦合系统参数优化设计提供参考,有助于实现光纤耦合的大气激光通信系统. 相似文献
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根据电磁场模场匹配理论,分析了自由空间光-布拉格光纤的耦合效率.通过对空间光-布拉格光纤耦合效率的计算可以知道,耦合效率与布拉格光纤纤芯半径、焦点光斑光腰半径和纤芯波矢有关.通过优化合理选择空间光聚焦后光腰半径与布拉格光纤纤芯半径以及纤芯波矢可以有效提高耦合效率.本文还对外界振动造成耦合透镜与布拉格光纤对接不正而对空间光-布拉格光纤耦合效率影响进行了分析.这对光纤激光雷达系统以及空间光通信系统的空间光-布拉格光纤耦合效率分析具有极其重要的参考价值. 相似文献
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使用光线追迹法分析高斯光束的透镜变换过程。首先使用高斯光束的透镜变换公式计算透镜的焦距及放置位置等耦合系统的参数,然后建立直角坐标系并利用耦合系统的参数构建方程,对边缘光线追迹,计算出像方束腰半径值。根据两种不同方法计算的束腰值计算激光束与光纤的耦合效率并进行比较,得出透镜的球差使得耦合效率降低的结论。最后采用双胶合透镜对球差适当的消除,耦合效率得到提高。 相似文献
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给出了一种处理激光二极管经透镜与单模保偏光纤耦合的精确方法,测量了半导体激光器的光束质量,对其光束的收集、准直、整形、聚焦和耦合进入光纤进行了实验研究,同时测量了整形系统和光纤的定位灵敏度.对球面微透镜光纤与激光二极管耦合的方法进行了理论分析,讨论了透镜参数、耦合形式、激光二极管波像散对耦合效率和特性的影响,给出了2种实际耦合系统的实验计算结果,并与理论计算作了比较,结合实验得到了微透镜的优化参数,且将结果应用到了激光二极管与单模保偏光纤耦合实验中,得到了总的耦合效率为36%. 相似文献
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采用光纤部件的自由空间光通信系统需要把接收到的光束耦合进单模光纤中,然而由于大气湍流的影响,使光纤耦合效率下降。自适应光学能够减小大气湍流效应,提高光纤耦合效率,根据大气湍流参数的空间光到单模光纤耦合效率表达式,得到了自适应光学校正下单模光纤耦合效率表达式,仿真结果显示:自适应光学能够增加空间相干长度,从而有效提高光纤耦合效率。同时还研究了斯特列尔比与耦合效率的关系,结果表明:无论有无自适应光学校正,两者都具有很好的拟合关系,因此在实际中可以用比较简单的斯特列尔比近似估计耦合效率。 相似文献
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为了克服光纤激光外腔谱组束系统中增益带宽和透镜像差对组束阵元数量的限制,在系统中加入了微透镜阵。根据光束变换理论,建立了基于微透镜阵的光纤激光外腔谱组束系统的外腔耦合效率分析模型。通过数值模拟,对各种相关参数对耦合效率的影响进行了仿真分析。结果表明:微透镜阵的加入极大提高了阵元的耦合效率和系统的组束潜力;为了获得尽可能高的耦合效率,需要对离焦量进行合理配置并设计具有较长焦距的微透镜;横向对准误差是影响耦合效率的主要因素,对于宽度为10 mm的组束光纤阵列,为保证60%以上的耦合效率,在θy≤2 mrad的同时需将横向位置偏移量δy限制在10μm以内。 相似文献
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Meihua Shen Wilfred Pau Nicolas Gani Jianping Wen Shashank Deshmukh Thorsten Lill Jian Zhang Hanming Wu Guqing Xing 《半导体技术》2004,29(8)
This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration. 相似文献
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White organic light-emitting devices based on fac tris(2- phenylpyridine) iridium sensitized 5,6,11,12-tetraphenylnap -hthacene 总被引:1,自引:0,他引:1
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V. 相似文献
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Complete approach to automatic identification and subpixel center location for ellipse feature 总被引:1,自引:0,他引:1
XUE Ting WU Bin SUN Mei YE Sheng-hua 《光电子快报》2008,4(1):51-54
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction. 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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Credence Systems Corporation 《半导体技术》2004,29(9)
Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V. 相似文献
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YUXiao-hua XIANGYu-qun 《半导体技术》2005,30(2):30-32,37
An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB. 相似文献
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It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV). 相似文献