A test object with a line width less than 10 nm for scanning electron microscopy

Data are given on the test object for scanning electron microscopy in which the components (ridges) are of trapezoidal profile and have large angles of inclination for the side walls. The width of the top surface of a projection is less than 10 nm. Methods have been developed for measuring such dimensions of test objects on standard scanning electron microscopes. __________ Translated from Izmeritel'naya Tekhnika, No. 8, pp. 20–23, August, 2008.     

高能球磨制备TiB_2/TiC纳米复合粉体

研究了通过高能球磨制备ＴｉＢ２／ＴｉＣ纳米复合粉体的反应过程和机理,对粉体的显微结构进行了表征．实验结果表明,采用金属 Ｔｉ和 Ｂ４Ｃ为原料,在球磨过程中, ＴｉＣ先于 ＴｉＢ２形成．球磨５ｈ后Ｔｉ与Ｂ４Ｃ反应生成ＴｉＢ２和ＴｉＣ,在随后的长时间高能球磨过程中ＴｉＢ２和ＴｉＣ两相保持稳定．球磨 ３０ｈ后,直径约 ８ｎｍ的 ＴｉＣ纳米粒子分布在 １００～２００ ｎｍ的 ＴｉＢ２粒子中,形成均匀分布的纳米ＴｉＢ２／ＴｉＣ复合粉体．     

Fractal characteristics of electric properties of coal

In the light of fractal geometry theory, the characteristics of coal＇s electric parameters （including dielectric constant, alternating conductivity, dielectric loss angle tangent and electric polarization constant） were studied by using literature data. The results are shown that the electrical properties of coal have fractal characteristic. The fractal dimensions of dielectric, alternating conductivity, dielectric loss angle tangent were obtained, and are relative to the content of pyrite sulfur, heat and ash content of coal.     

热网高失水率的原因与防治措施

分析了热网高失水率的原因与防治措施。     

Efficient visual communication channels

This paper compares the efficiency of uniform quantization in the spatial domain with frequency dependent quantization in the spatial frequency domain, in the context of the end-to-end performance of visual-communication channels. Results show that the minimum data density required for informationally lossless transmission depends on the design of the image-gathering device. The information in the acquired signal, not the energy, dictates the trade-off between data transmission and visual quality. Frequency dependent quantization that maintains the information capacity of the channel while reducing the entropy of the encoded signal, improves its information efficiency. Information bit-allocation is preferable for optimized visual communication for restoration, whereas energy bit-allocation can be used only for image reconstruction.This research was supported by NASA Task Assignment NAS1-18584-90 with the Department of Mathematics, Old Dominion University, Norfolk, Virginia 23529.     

基于潮流跟踪的最小负荷削减费用计算

电网可靠性的经济性价值日益受到人们的重视,如何对其进行定量计算具有重要的现实意义.该文建立了体现电网可靠性经济价值的负荷削减费用模型,模型中综合考虑了节点负荷用户类型的分类和缺电损失评价率随停电时间的变化情况.在潮流跟踪法的基础上,提出了衡量负荷削减对缓解系统过负荷支路程度的经济性指标,并利用该指标对模型进行求解.算例结果验证了该方法的有效性和实用性.     

镀厚膜工艺技术研究

通过分析现有镀膜工艺设备的电子束加热原理、结构和热量损耗,并针对实际应用过程中镀膜存在的问题,提出了对现有设备的改进措施,开发出一种新的镀厚膜工艺,较好解决了芯片镀厚膜的工艺技术难题和存在的镀厚膜工艺质量问题,大大提高了镀厚膜工艺的工作效率,极大地改善了特高压超大功率电力电子器件的电性能参数,收到了良好的效果.     

基于GRNN与注意力机制模型的非侵入式家用负荷分解

为了提高识别精度,提出一种基于GRNN与注意力机制模型的非侵入式家用负荷分解方法.采用批标准化来减少神经网络层与层之间的耦合,利用GRNN强大的时间序列特征表示能力,来提取电力负荷入口处测得的总用电信息与各电器能耗之间的关系,同时利用注意力机制来减少模型的权重参数.最后通过算例验证了算法的可行性与优越性.     

热暴露对SiC纤维增强Ti基复合材料基体织构的影响

本文利用电子背散射衍射（EBSD）技术,研究了高温热暴露对SiC纤维增强Ti-6A1—4V复合材料基体织构的影响。结果表明,相对于制备态复合材料较为集中的晶粒取向,900℃10h热暴露后的复合材料其晶粒生长的方向既有基面方向,又有棱面方向,同时还存在锥面方向。随着热暴露时间的延长,900℃75h热暴露的复合材料基面方向的生长方式与900℃10h热暴露的复合材料情况恰好相反。另外,无论是基面方向还是棱面方向,随着热暴露时间的延长,晶粒生长的取向均有向单一取向演化的趋势,且锥面方向上的生长会逐渐消失。     

农电实现降损增效的途径讨论

线损率和抄核收到位率是农电管理的重要经济技术指标,也是农电生产经营管理水平和实现经济效益的综合反映。多管齐下,加强用电管理,降低线损率,确保抄核收工作到位是实现农电降损增效的有效途径。