共查询到20条相似文献,搜索用时 15 毫秒
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三维(three- dimensional,3D) 发射层析技术(emission computerized tomography,ECT) 是一种简单、高效且准确的燃 烧场3D成像与检测技术,其中权重矩阵的计算 精度决定了层析重建的精度和质量。本文研究了一种基于高密度子网格光线追迹的权重矩阵 计算方法, 将被测区域划分为密度更高的子网格,并根据相机成像模型实现光线追迹,以确定离散网格 对投影像素 的权重因子。数值模拟和燃烧火焰重建实验表明该算法具有较高的精度和计算效率。该研究 对于3D发射层析技术的实用化具有重要的理论意义。 相似文献
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针对现有的声发射监测系统中存在的监测范围窄,通信距离短,监测仪固件升级困难的问题,提出了一种基于串口服务器的远程多通道声发射监测系统设计方案。该系统下位机采用C8051F020单片机作为控制器,上位机采用Winform设计。经测试,系统具有监测范围广,运行稳定可靠,人机界面友好的特点。 相似文献
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针对SPM探测器的特点,采用TSMC 0.18μm CMOS工艺,设计了基于SPM的PET前端读出ASIC芯片,包括RGC前置放大器、积分器、整形器、采样保持电路等能量测量电路,以及鉴别器、单稳态电路等时间测量电路.Hspice仿真结果表明,该电路能够完成对SPM探测器输出信号的读出和处理功能,满足PET系统设计要求. 相似文献
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针对金鸡岭台发射机房的实例,提出了用计算机网络控制和管理发射机的设想,并设计出详细的硬件及软件解决方案。 相似文献
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Zhu Dazhong 《电子科学学刊(英文版)》1999,16(1):88-92
The device structure and technical processings of quasi-planar self-aligned silicon avalanche electron emission array arc introduced. The processing step at the edge of electron emission region is about 10nm only and the width of self-aligned current channel of shallow As implantation is about 3μm. Its I-V characteristics show a larger linear region and lower series resistance than that of the previous silicon avalanche electron emission devices. Some of the electron emission characteristics are also discussed in this paper. 相似文献
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A probe-hole field emission microscope system,controlled by the Apple Ⅱ computer,has been developed and operated successfully for measuring the work function of a single crystalplane.The detection screen,the phototube and the amplifier are combined for measuring theprobe-hole current.The combination is calibrated and the calibrated data are used in the com-puter program.The high voltage on the viewing screen is adjusted by using a D/A converter.The total current and the probe-hole current are acquired by using an A/D converter.A programin BASIC is used for processing all data and the Fowler-Nordheim plot parameters are given.Work functions of single crystal planes can then be calculated;as examples,the work functionson the clean W(100)and W(111)planes are measured to be 4.67 eV and 4.45 eV,respectively. 相似文献
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激光引信包含精密光学系统,其中光学接收系统占重要地位,在常规弹药引信过程的应用中,高发射过载环境对系统弱回波聚焦质量造成严重影响,系统工作可靠性无法保证。提出接收聚焦透镜与窄带滤波片一体化方案,设计出一种新型缓冲结构接收系统光学,应用有限元分析软件ANSYS建立传统激光接收系统以及新型结构动力学模型,对接收聚焦透镜进行非线性动力学仿真以及ZEMAX光学仿真;最后进行空气炮冲击实验,结果表明:在经历70 000 g冲击加速度后,新型光学系统缓冲结构可有效缓解接收聚焦透镜塑性变形,提高脉冲激光束聚焦整形质量,激光回波能量显著增强。为常规武器激光引信接收光学系统抗高过载设计提供了一种新的方法和理论依据。 相似文献
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A new localized computerized tomography technique based on the multiresolution analysis (MRA) implementation of the discrete wavelet transform is proposed. Our technique is based upon viewing the projection data as a set of one-dimensional functions of the space variablet and decomposing each one into an approximation signal and a set of detail signals using MRA. The approximation signal and detiil signals associated with each projection are filtered using the ramp filter || of the standard reconstruction technique filtered back projection to generate the set of filtered projections. It is shown that only a very sparse set of projection data outside of the region of interest (ROI) is required to reconstruct a high-quality image of the ROI and a reasonable image outside of the ROI. Simulation results using the Shepp-Logan head phantom are presented to demonstrate the proposed technique. 相似文献
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生物超微弱发光研究进展 总被引:6,自引:0,他引:6
综述了自 192 3年以来的生物超微弱发光 (UPE)研究进展 ,总结了UPE的主要检测方法 ,概括说明了UPE作为生命系统普遍存在的一种现象 ,其研究不仅对生命科学领域具有重大的科学意义 ,在农业、医学、食品和环境科学等领域也具有广泛的应用价值。同时展望了其未来的研究方向 相似文献
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基于DSP的16通道声发射同步数据采集电路设计 总被引:1,自引:0,他引:1
针对煤岩声发射信号监测系统的需求,采用16位定点DSP芯片TMS320VC5509A和高精度A/D转换器ADS1278设计了一种具有24位分辨率、16通道同步数据采集功能的数据采集电路。控制接口采用I2C接口扩展I/O的方式实现,数据接口采用McBSP接口以帧同步方式实现,2片ADS1278采用菊花链的方式级联。给出了硬件电路、底层软件和测试结果,该数据采集电路具有接口简单、高性能、低功耗、设置灵活等特点,已经应用于课题组研制的煤岩声发射监测系统中。 相似文献
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详细讨论了煤矿井下瓦斯自动排放系统的智能组合开关设计方法。通过研究煤矿井下掘进面通风的特点和规律,总结出一种掘进面自动排放瓦斯方案,在此基础上设计了瓦斯自动排放系统,着重讨论了作为该系统控制核心的智能组合开关设计方法,阐述了装置内部总线控制结构、硬件电路、软件逻辑的原理。经验证,该装置的性能指标完全满足应用要求,运行可靠稳定,能够应对井下掘进面复杂的使用环境。 相似文献
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《Organic Electronics》2014,15(7):1396-1400
A three-terminal organic light-emitting device with a periodic interrupted middle electrode is developed to allow for an adjustable emission color. The emission results from three independent light-emitting diodes with one diode utilizing exciplex emission. An equivalent electrical circuit is suggested taking the current–voltage characteristics and the direction of current flow through the organic structure into account. Two diodes are formed between the embedded middle electrode and the LiF/Al top and ITO bottom electrode, respectively, and the third diode utilizes that part of the device without the middle-electrode exhibiting exciplex emission. It will be shown that the spectrum of the emitted light can be tuned from blue to orange by controlling the applied potentials to the device terminals. 相似文献