NVCGM高性能灌浆料的研究及应用

从流变性、竖向膨胀、有效承载接触面积、抗压强度等方面,采用对比试验的方法,系统分析了 NVCGM 灌浆料与国外两种灌浆料、国内某灌浆料的优劣性。试验结果以及工程应用表明,NVCGM 灌浆料是一种综合性能优异的高性能灌浆料。     

小口径弹药引信定距精度分析

从理论上分析了影响引信定距精度的因素,利用试验数据,对连发射击时引信定距精度变差的原因作了定性分析,对武器系统的使用提出意见和建议.     

双层辉光离子渗Ni-Cr-Mo-Cu合金的工艺

在20钢基材上,利用双层辉光离子渗金属技术进行Ni-Cr-Mo-Cu多元共渗正交实验工艺研究.结果表明,工艺参数对渗层的元素总含量以及渗层的厚度有较大的影响,并确定了最佳工艺参数为源极电压1050V,工件电压250V,气压35Pa,极间距15mm.     

基于有限样本的大气偏振模式生成方法

大气偏振模式在导航等领域具有广阔的应用前景,但是由于受到大气偏振信息采集装置物理特性的限制,在同一时刻只能获得局部的、不连续的偏振信息,对实际应用产生影响。针对此问题,本文通过挖掘大气偏振模式分布的连续性,提出一种大气偏振模式生成方法,从局部的偏振信息生成全天域的大气偏振模式。此外,偏振信息往往受到不同的天气条件、地理环境等因素的影响,而这些偏振数据在真实环境中难以采集。针对此问题,本文挖掘不同天气、地理条件下有限样本数据之间的多样性关系,以此关系将生成的大气偏振模式泛化到不同的条件下。本论文在仿真数据和实测数据上进行了实验,并与其它最新方法进行对比,实验结果证明了本文方法的优越性和鲁棒性。     

Direct Ink Writing of Highly Conductive MXene Frames for Tunable Electromagnetic Interference Shielding and Electromagnetic Wave?Induced Thermochromism

The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interfer?ence (EMI) shielding materials to ...     

Phase change memory alloys: GST cell array characterization using picosecond ultrasonics

Phase change random access memory alloys (PRAM or PCM) are a class of non-volatile memory that is thought as viable alternatives to flash memory technology or to supplement other memory technologies depending on the end applications and its key performance requirements. Ge₂Sb₂Te₅ alloy (GST) is the most widely used chalcogenide material for PCM application, and has many unique properties, including strong temperature-dependent film properties, low thermal conductivity, and high electrical resistivity. Picosecond ultrasonics was used to make non-contact, non-destructive measurements of GST films on blanket wafers and directly on product wafers. On-product wafer measurements were made on various via array (0.5 μm and 1 μm between cell edges with CD size from 250 to 800 nm). Measurements have shown excellent correlation to cross-section SEM and were consistent with CMP polish times for both blanket and pattern wafer measurement. Excellent repeatability based on extensive measurements demonstrates the capability and reliability of picosecond ultrasonic technology. Picosecond ultrasonic measurements also provide rapid characterization across the whole wafer at production-worthy throughputs.     

美国联邦检察官的地方反腐行动之正当性辨析

美国司法部在未获得国会立法明确授权的情况下,自上世纪70年代初始启动了由联邦检察官直接参与调查和检控各州腐败官员的大规模廉政行动.该行动历时四十余年,取得了显著成效,但一直被美国各界持异议者视为对各州及地方政府的政治独立和现代法治构成了最为严重、最具破坏性的侵蚀.立足于美国语境,从联邦检察官与各州民选检察官之间的比较优势、联邦法官群体反腐伦理倾向、社会舆论基础以及美国实用主义政治、法律传统等多维角度,探究联邦检察官的地方反腐行动得以正当化的因素,有助于加深对美国民主与法治的认识,吸取有益于中国反腐实践的经验.     

Detection of cracks in simply-supported beams by continuous wavelet transform of reconstructed modal data

This paper proposes a new approach for damage detection in beam-like structures with small cracks, whose crack ratio [r = H_c/H] is less than 5%, without baseline modal parameters. The approach is based on the difference of the continuous wavelet transforms (CWTs) of two sets of mode shape data which correspond to the left half and the right half of the modal data of a cracked simply-supported beam. The mode shape data of a cracked beam are apparently smooth curves, but actually exhibit local peaks or discontinuities in the region of damage because they include additional response due to the cracks. The modal responses of the damaged simply-supported beams used are computed using the finite element method. The results demonstrate the efficiency of the proposed method for crack detection, and they provide a better crack indicator than the result of the CWT of the original mode shape data. The effects of crack location and sampling interval are examined. The simulated and experimental results show that the proposed method has great potential in crack detection of beam-like structures as it does not require the modal parameter of an uncracked beam as a baseline for crack detection. It can be recommended for real applications.     

珠海发电厂电动给水泵电动机保护动作分析

珠海发电厂1号机1号电动给水泵启动中综合保护继电器保护动作,跳开电动给水泵电源开关,马达端盖出风口有青黑色烟气冒出.根据综合保护继电器记录数据,利用矢量分析法,结合继电保护及电力系统稳态、暂态理论知识,在最短时间内分析出电动机发生了B相绕组匝间短路,为确定电动机故障点提供了理论支持,确保了故障电动机的及时维修,并在电动给水泵进行解体后,验证了理论分析的正确性.     

A DCT-based multipoint video composition scheme

针对视频会议应用中传统的像素域多路视频混合方法存在运算复杂度高、画面质量损伤的问题,提出了一种基于压缩域的替代方法,并给出了详细的码流映射算法步骤.该方法按照混合后多画面的空间位置关系,通过对输入的多路码流中宏块编码次序的重排和语法元素的映射,在码流级别将多路视频合成到同一画面中,并采取提前量化策略消除可能出现的二次量化失真,从而可兼具处理速度快和高保真的双重优点.以H.263为例验证了此方法的有效性.实验结果表明,与编解码器级联的方法相比,此方法的峰值信噪比(PSNR)平均提高2dB,运算效率提高百倍以上.此研究工作有望为正在制定的国际视频编码标准H.265贡献一种视频混合解决方案.