高速钢的氧化失重回归方程

在实验数据的基础上,对Ｗ９、Ｍ２、Ｍ２Ａ１、Ｄ６０６４种高速钢在空气中加热时的氧化失重进行回归分析,得到回归方程,并讨论了加热温度和时间对４种高速钢氧化失重的影响。     

采用人工神经网络技术对高压线缆绝缘破坏预测的研究

采用神经网络技术,进行了预湍高压输电线缆接头处绝缘破坏的试验研究,实验中神经网络的学习方式采用了随机逼近方法,这种方法很容易用结构简单且造价便宜的模拟电路实现,本试验结果还证实了利用神经网络技术对预测高压输电线缆接头处绝缘破坏是可行的。     

Silver-mirror-based multipass preamplifier for a broadband terawatt Ti:sapphire laser

We have developed a silver-mirror-based multipass preamplifier for a broadband amplification in a terawatt Ti:sapphire laser. With the extremely broad bandwidth of the silver mirrors, a very broad amplified spectrum can be generated at an amplified energy of 4 mJ; the amplified spectral width is 65 nm at half maximum and 160 nm at -25 dB without any spectral shaping technique. Such a broad amplification can be explained well by the simulation that includes gain narrowing and gain saturation. Even after a further amplification to an energy of 600 mJ, the amplified spectrum is broad enough to support an approximately 20 fs transform-limited pulse duration.     

一种基于RGV、AGV的柔性输送系统

随着现代制造业的迅速发展,我国的物流行业也随之崛起,并且逐渐受到全社会的广泛关注。早期的人工物流、机械化物流方式,已经远远不能满足现在大规模生产流水线的需求。本文提出了一种基于RGV、AGV的柔性输送系统,其中环形RGV输送系统通过成对的码头和码头之间的流水线与AGV输送系统、非环形往复式RGV输送系统相接驳;AGV输送系统和非环形往复式RGV输送系统用于将物流货品从环形RGV输送系统送入或送出指定物流系统。该系统有效地克服传统单一RGV输送系统对使用场所的适应性差、轨道占用空间大等缺点,同时避免使用单一AGV输送系统带来的输送效率较低、设备及维护成本较高等问题。     

On the compression and streaming of concentric mosaic data for free wandering in a realistic environment over the Internet

In this paper, we describe a system for wandering in a realistic environment over the Internet. The environment is captured by the concentric mosaic, compressed via the reference block coder (RBC), and accessed and delivered over the Internet through the virtual media (Vmedia) access protocol. One of the key contributions of the paper is the proposal of the RBC concentric mosaic coder. The RBC coder not only compresses the huge dataset of the concentric mosaic very efficiently, but also produces a well-organized bitstream that can be accessed just-in-time (JIT). To reconstruct a virtual view, only a portion of the RBC bitstream needs to be accessed and decoded. This greatly reduces the memory and computation requirement of the viewer compared with first decoding the entire concentric mosaic data set and then rendering from the decoded data. Our second contribution is the employment of the Vmedia protocol to deliver the compressed concentric mosaic bitstream just-in-time over the Internet. Only the bitstream segments corresponding to the current view are streamed over the Internet. The delivered bitstream segments are managed by a local Vmedia cache, so that frequently used bitstream segments do not need to be streamed over the Internet repeatedly, and a RBC bitstream larger than the memory capacity can be easily handled. Combining RBC and Vmedia, a concentric mosaic interactive browser is developed through which the user can freely wander in a realistic environment, e.g., rotate around, walk forward/backward, and sidestep, even under a tight bandwidth.     

Effects of atomic size difference and heat of mixing parameters on the local structure of a model metallic glass system

Atomic size differences between constituting elements and the heat of mixing are key factors in designing a metallic glass system. In this study, the effects of atomic size differences and the heat of mixing on the glass-forming ability and the local structure of metallic glasses were studied via molecular dynamic simulations of an ideal system known as the Lennard-Jones embedded-atom method model. The atomic size difference and the heat of mixing of the system were varied by means of the Lennard-Jones parameters. The glass transition behavior was characterized based on the chemical short-range order and by a Voronoi analysis. Our simulations lead to optimized windows of atomic size differences and heat of mixing parameters for metallic glass-forming of the model system. Both a greater negative heat of mixing and a larger atomic size difference are necessary for the enhancement of the glass-forming ability.     

Process variation compensation technique for voltage‐controlled ring oscillator

A voltage‐controlled ring oscillator with process variation compensation circuits is designed using 0.25 µm CMOS technology. The simulation results show that the proposed ring oscillator increases the guaranteed frequency tuning range by 12% compared to a conventional ring oscillator. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

弯管塑性极限载荷分析

利用Von-Mises屈服准则,推导出内压和扭矩联合载荷以及内压、弯矩与扭矩联合载荷作用下弯管的塑性极限载荷方程,经过简化后可得到任一单个载荷、两个或3个载荷共同作用下的塑性极限载荷.有关实验验证了理论的正确,为充分挖掘弯管的塑性极限承载能力提供了理论依据,也为研究有缺陷弯管塑性极限载荷提供了方法.