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991.
The NH3-plasma passivation has been performed on polycrystalline silicon (poly-Si) thin-film transistors (TFT's), It is found that the TFT's after the NH3-plasma passivation achieve better device performance, including the off-current below 0.1 pA/μm and the on/off current ratio higher than 108, and also better hot-carrier reliability than the H2-plasma devices. Based on optical emission spectroscopy (OES) and secondary ion mass spectroscopy (SIMS) analysis, these improvements were attributed to not only the hydrogen passivation of the defect states, but also the nitrogen pile-up at SiO2/poly-Si interface and the strong Si-N bond formation to terminate the dangling bonds at the grain boundaries of the polysilicon films. Furthermore, the gate-oxide leakage current significantly decreases and the oxide breakdown voltage slightly increases after applying NH3-plasma treatment. This novel process is of potential use for the fabrication of TFT/LCD's and TFT/SRAM's  相似文献   
992.
一种识别薄板对接接头的视觉方法   总被引:1,自引:0,他引:1  
对薄板紧密对接接头的识别问题进行了深入的分析,提出了由照明、自适应局部特征提取、全局特征识别和验证融合在一起的视觉识别方法。它克服了电弧光的干扰,识别结果可靠,可以有效地解决薄板紧密对接接头识别这一难题。  相似文献   
993.
利用ATM构造宽带INTERNET骨干网   总被引:2,自引:0,他引:2  
林殿魁 《世界电信》1997,10(1):22-24
本文分析了传统的Internet骨干网的组网方案纯路由器网络的成功及其所面临的挑战,提出在网络核心引入交换技术,通过采用ATM构造带宽Internet骨干网,可以构更大规模的网络,使网络运营者受益,并且为将来Interne提供综合业务奠定坚实的基础。  相似文献   
994.
A family of millimeter-wave sources based on InP heterojunction bipolar transistor (HBT) monolithic microwave/millimeter-wave integrated circuit (MMIC) technology has been developed. These sources include 40-GHz, 46-GHz, 62-GHz MMIC fundamental mode oscillators, and a 95-GHz frequency source module using a 23.8-GHz InP HBT MMIC dielectric resonator oscillator (DRO) in conjunction with a GaAs-based high electron mobility transistor (HEMT) MMIC frequency quadrupler and W-band output amplifiers. Good phase noise performance was achieved due to the low 1/f noise of the InP-based HBT devices. To our knowledge, this is the first demonstration of millimeter-wave sources using InP-based HBT MMIC's  相似文献   
995.
Phase-induced intensity noise from weak multiple reflectors is evaluated theoretically and experimentally in amplifier cascades without isolators. Rayleigh backscattering alone significantly limits the number of amplifiers in the span. Theory and experiment agree closely for a six-amplifier cascade.<>  相似文献   
996.
巨登峰  林金浩 《油田化学》1993,10(2):120-123
本文介绍了以悬浮型速溶PHPAM为基础研制的低温油井堵水剂,讨论了影响堵水剂交联时间和成胶粘度的因素,制定了移动式弹性隔板堵水工艺并成功地应用于二连油田蒙古林砾岩油藏的油井堵水。该堵剂适用于30—60℃油井,交联时间可控、配制简便、快速、施工周期短。  相似文献   
997.
The jugular bulb varies widely in position and dimensions. A high jugular bulb is not an uncommon finding in temporal bones. Besides our five cases with different clinical manifestations, we review 52 cases diagnosed clinically and published previously in the English literature. The high jugular bulb occurs more often on the right temporal bone. Certain pathologic conditions, such as an abnormal bone formation, an aberrant sinusojugular system, or decreased pneumatization of the mastoid bone, may predispose an individual to its occurrence. Most people with this anatomical variation remain asymptomatic. However, various otologic problems and symptoms may be attributed to this condition. A high resolution computed tomography scan is the most convenient diagnostic tool at present. Law projection plain mastoid radiography may reveal a high jugular bulb in certain cases, providing a preoperative warning to an otologic surgeon. An exploratory tympanotomy is not suggested for those with a high jugular bulb with a conductive hearing loss, while jugular vein ligation has been reported to have good results in alleviating intractable pulsatile tinnitus. For most asymptomatic patients, regular long-term follow-up is recommended.  相似文献   
998.
双能X射线骨密度仪测定技术研究   总被引:6,自引:0,他引:6  
以Lunar公司DPX-L型双能X射线骨密度仪为例,研究引起测量误差的主要因素并提出质控措施。用自检模块、腰椎体膜评定仪器的体外测量精度好于1%。对10位志愿者重复2次测量,体内精度对腰椎,MPD(平均百分差)为0.46,CV(变异系数)为0.75;对股骨颈,MPD为1.26、CV为0.47;Ward’s三角区MPD为2.01、CV为1.14;大转子MPD为1.66、CV为0.72。扫描图像由2位  相似文献   
999.
Surface area and porosity of pellets containing alumina/carbon powder mixtures during reduction and nitridation were determined. The experimental results indicated that surface area and porosity of solid samples were decreased by increasing the reaction temperature, grain size, forming pressure and the amount of catalyst. Increasing the molar ratio of C/Al2O3 and gas flow rate could decrease the surface area and increase the porosity of the solid sample.  相似文献   
1000.
To size networks that support switched multimegabit data service (SMDS), one must determine how much additional capacity is needed and where it is needed so as to minimize the total capacity augmentation cost. Two combinatorial optimization problem formulations are considered and compared for their relative applicability and complexity. A solution procedure based on Lagrangean relaxation is proposed for one of the formulations. In computational experiments, the proposed algorithm determines solutions that are within a few percent of an optimal solution in minutes of CPU time for networks with 10-26 nodes. The proposed algorithm is compared with a most congested first (MCF) heuristic. For the test networks, it achieves up to 152% improvement in the total cost over the MCF heuristic  相似文献   
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