46 research outputs found

    Detection Algorithm Based on Consecutive FramesSubtraction and Codebook Model

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    中文摘要:针对视频检测对实时性和准确性的要求, 提出了将帧间差分与码书模型相融合的运动目标检测算法。首先, 选取某个 t 时间内采集到的视频图像作为训练图像, 对图像的每一个像素点建立码书模型。把码书模型中表示前景的码书去除, 余下 的作为背景模型用于检测。检测运动目标时, 先将待检测的相邻帧图像进行帧间差分, 得到变化区域和没有变化的区域, 将 有变化的区域与背景模型进行拟合, 区分出前一帧运动区域和目标运动区域。更新背景模型时以不同的更新方法对前一帧 运动区域和目标运动区域进行更新。 英文摘要:Aimed at the real- time and veraci ty of current algori thm for detecting moving objects ,an algori thm bas ed on two con- s ecutive frames subtraction and codebook model is pres ented.Firs t,s elect the video images which are col lected in a con- s ecutive time as the training images ,es tabl ish a codebook for every pixel of the images .From the firs t two images on,sub- tract two cons ecutive frames to find out moving areas and background areas .Compare the moving areas wi th the back- ground model to decide whether the moving area is the moving objects or not.The background updating algori thm varies in the rate of updating according to the different areas of the image

    X-ray Investigation on the Change of Surface internal stress depend on the Heating in Twisting work material.

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    The change of microscopic surface internal stress depend on the passage of time and high vacuum annealing in Twisting work materials were studied by the X-ray. The following results were obtained from the experiment. (1) Immediately load off, the round bar specimen which was subjected a twisting deformation have a compressive internal stress together with a Longitudinal direction or a Tangential direction in the surface of specimen. (2) The recovery of surface internal stress finished about 48 times, get to a stable condition together with a 0.2% carbon steel (S20C), or a high tensile aluminum alloy (17S) and a electrolytic copper (CuB-1). (3) In the neighbourhood of the recrystallization temperature of each materials, the surface internal stress and the value of half breadth were exibited the heaty decrease. The surface internal stress point out a remarkable decrease, according to the twisting deformation become larger. (4) In a 0.2% carbon steel (S20C), (211) diffraction line tend to separetes K_ and K_ at between 350℃ and 450℃. In a high tensile aluminum alloy (17S), (333) diffraction line separetes K_ and K_, at 250℃, it seems that the recrystallization occuring at these temperature

    Investigation of Porous Silicon/Carbon Composite as Anodes for Lithium Ion Batteries

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    以商业化多晶硅粉为原料,采用金属银催化剂诱导化学腐蚀的方法制得三维多孔硅材料。通过优化腐蚀条件,得到孔径约为130 nM,比表面为4.85 M2/g的多孔硅材料。将多孔硅和PAn溶液混合球磨并经高温烧结后在多孔硅表面包覆上一层致密的无定形碳膜,从而制得多孔硅/碳复合材料作为锂离子电池的负极材料。3d多孔硅结构可以缓解电化学嵌/脱锂过程中材料的体积效应,无定形碳膜层可有效改善复合材料的导电性能。电化学性能测试表明,该多孔硅/碳复合负极材料电池在0.4 A/g的恒电流下,首次放电容量3345 M AH/g,首次循环库伦效率85.8%,循环55次后容量仍保持有1645 M AH/g。并且在4 A/g的倍率下,容量仍维持有1174 M AH/g。该方法原料成本低廉,可规模化生产。3D porous silicon was synthesized by metal-assisted chemical etching process using commercially available polycrystalline silicon powders.After chemical etching in optimized solution, 3D porous silicon structures with pore size of about 130 nm and specific surface area of about 4.85 m2/g was obtained.Subsequently, the 3D porous silicon powders treated with ball milling and heat carbonization processes were coated with amorphous carbon and utilized as the anode electrode material for lithium ion battery.The combination of the 3D porous structure and a carbon coating layer can accommodate large mechanical strains by providing the empty space of the pores to alleviate the volume change, and by increasing the electrical conductivity with the carbon layer.The electrodes achieve an initial charge capacity of 3345 m Ah/g with coulombic efficiency of 85.8% as well as a high reversible capacity of 1645 m Ah/g after 55 cycles at 0.4 A/g.And it is capable to retain a capacity of 1174 m Ah/g even at 4 A/g.Thus, this work introduces a novel and easy potential industrial method for fabrication Si/C materials for high-performance lithium ion battery.国家自然科学基金(61176050;21233004)~

    Study of Improving Output Power of Double Glass Polycrystalline Silicon Photovoltaic Module

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    多晶硅电池及组件的降本和提效是光伏行业重点关注的热点问题。本文重点研究双玻多晶硅组件的提效途径,通过改变双玻光伏组件中电池片尺寸降低封装损失和电路损失,从而提高电池片转换效率;通过封装工艺和贴膜工艺提高电池片表面太阳光入射强度,从而提高电池片转换效率。主要研究结果如下: 1、划片工艺影响电池片的良率和转换效率。采用启澜GSC-20F激光划片机的最佳切割工艺为:对电池片进行反面切割,重复切割次数为两次;实验所用激光器最佳切割参数为激光功率为17W,切割频率为40kHz,划片速度为110mm/s。 2、小尺寸电池片有利于组件输出功率的提升。组件的电学性能损失随着电池片的尺寸减小而减小。经过产线...The hot topics of photovoltaic market are reducing costs and improving the output power of solar photovoltaic module. In this paper, methods of improving the output power of double glass polycrystalline silicon photovoltaic module were investigated. The package loss and electricity loss of photovoltaic module were reduced by changing the cell size in them to improve the transformation efficiency. ...学位:工学硕士院系专业:材料学院_工程硕士(材料工程)学号:2072014115012

    Study on the carbonitriding cast iron by liquid micro-discharge plasma

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    液相微弧放电等离子体电解碳氮共渗技术是一种新兴的表面改性技术。相对于传统表面改性技术,它具有能耗低、不需要真空装置、成本小、环境污染小、工艺简单等特点,在航空航天、军工、机械、电子、医疗、装饰等许多领域具有广阔应用前景。 本论文采用液相微弧放电等离子体电解碳氮共渗技术,在乙酰胺甘油水溶液电解液体系中对铸铁表面进行了碳氮共渗处理。电源参数为:电流大小固定为3A,频率固定为100Hz,占空比固定为25%;电解液配方为:去离子水750mL,乙酰胺150g,甘油80mL,加入2g粉状NaCl颗粒以增加电解液的导电性。 与文献较多报道的将铸铁工件作为阴极工作电极实现渗碳氮化不同,本论文是基于铸铁工件...The liquid micro-discharge plasma carbonitriding technology is a novel surface modification. Compared to traditional technology, it has several advantages such as avoiding vacuum equipment, low cost, environmentally friendly and simple process. So it has many applications in various fields, such as aerospace, automotive, electronics industry, medical treatment. The carbonitriding cast iron by the...学位:工学硕士院系专业:物理科学与技术学院_工程硕士(电子与通信工程)学号:1982013115298

    Studies on Tuning Bars

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    Tuning bars or free-free bars are in use for the independent synchronization of Facsimile and Telephoto-transmission instead of tuning folks.Tuning bars are excellent in the simplicity of the form, and oscillators with these bars have good stability of the frequency. In this paper the author has given some notes regarding tuning bars, that is to say, non-linear vibration, zero temperature coefficient materials, temperature coefficient of bimetal tuning bars, radiation impedance, vibration losses, and new method of excitation of non magnetic materials.音片とは周知の様に,自由-自由棒であって,音叉或は音環に代り,模写電信叉は写真電送の独立同期用電源として利用せられて居るもので,製作の容易さと精度(周波数温度係数の少いことと電源電圧変動に対する安全度の高いこと)の優秀な特徴がある。著者も此の音片の特性向上のために二三研究する機会を得たので,茲に取りまとめて報告し,諸彦のご参考に資したいと考えて居る

    Evaluation of effect of combined mean stress on combined axial-torsional fatigue

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    Influence of superposition of combined static tension and torsion loading on in-phase combined axial and torsional fatigue life was investigated. Based on the analysis of the cyclic and static stresses acting on the maximum shear planes, fatigue life evaluation model for a shear dominated aterials was proposed. To confirm the validity of this model, fatigue tests were performed. Comparison of predicted life with actual life shows a good correlation
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