Analysis of time-delay systems using an alternative technique

The Taylor delayed operational matrix is first developed. With the introduction of the Taylor product matrix, the Taylor series approximation can be extended to the analysis of time-varying systems. The method is better than that using Walsh series, as demonstrated by numerical examples. The result is quite satisfactory.     

Manoeuvring target tracking in a cluttered environment from noisy images by an adaptive probabilistic data association filter

A new tracking method for estimating motion parameters of a manoeuvring target in a cluttered environment from noisy image sequences is presented. Traditionally, tracking systems have been broadly classified according to (1) moving target with or without manoeuvring, and (2) tracking in a clean (uncluttered) or cluttered environment. The difficulties studied here are those arising from (a) unknown acceleration inducing a randomly updated trajectory, and (b) the disturbance of returns from false alarms or other interfering objects. The probability data association filter (PDAF) is augmented by the semi-Markov process, called the adaptive PDAF, to handle the difficulties. Since the acceleration state applied either by a pilot or by a guidance control system is independent of the appearance of false returns, the treatment of target manoeuvring and false returns are separated into two sub-problems, i.e. the PDAF is applied to govern the disturbance of multiple returns and the semi-Markov process is applied to estimate uncertain accelerations. Three simulation results of variations show small biases from the true trajectory. By comparing with a nearest neighbour standard filter, the proposed tracking system also demonstrates better results.     

Error analysis of block-pulse series solutions

This paper examines the integral operational matrix used in block-pulse series analysis from the geometric point of view. It is found that using the integral operational matrix to obtain the block-pulse series coefficients of the integral of a function will cause errors that can be estimated from numerical analysis. Based on these errors, the deviation is estimated of the block-pulse series solution of a linear time invariant system from its exact solution.     

结合可中断合同交易的电力系统随机生产模拟

提出了一种结合可中断电力合同交易的电力系统随机生产模拟方法,其中把可中断电力等效为具有随机停运特性的灵活发电资源.考虑了可中断合同定价模型与合同交货时段系统边际运行成本之间的相关性问题,并采用一种迭代协调算法来加以解决.该方法可用于分析可中断电力合同交易对于系统发电可靠性和经济性的影响,以及考虑系统需求不确定性和发电机组故障的可中断电力合同的系统决策.算例仿真验证了该方法的有效性,并且表明在不确定环境下要求以尽可能小的成本来保证系统适当可靠性水平时,可中断电力合同交易具有重要应用价值.     

基于启发式搜索分离向量的凸多面体碰撞检测

碰撞检测是计算机模拟物理过程的基础，在计算机图形学、CAD／CAM、虚拟现实和机器人等领域有着广泛的应用．该文给出了一个新的用于凸多面体碰撞检测的算法——HP-jump．HP-jump建立了一个有效的碰撞检测模型用于报告物体的碰撞，同时提供了一个快速的启发式的策略用于搜索两个凸多面体的分离向量．该算法是利用凸多面体的层次表示来搜索支撑顶点对，用平衡二叉树来记录球面凸多边形的顶点，同时还利用了时间、空间相关性，这些都加速了算法的执行．该文的最后给出了HP-jump与GJK，I-COLLIDE算法的比较．     

In situ formation of titania film on NiTi alloy treated with hydrogen peroxide solution at low temperature

Chemically polished NiTi shape memory alloy（SMA） substrate was treated with a boiling aqueous solution containing hydrogen peroxide to form titania film in situ at low temperature. The surface characterizations of titania film on NiTi substrate were investigated by scanning electron microscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. The results show that titania film is successfully fabricated in situ on NiTi SMA by this surface oxidation method. It is mainly composed of rutile and anatase, whose surface compositions and morphologies are sensitive to H2O2 content. In situ formation mechanism of titania film on NiTi substrate was discussed based on the experimental results.     

PHYSICAL,CHEMICAL, and THERMAL CHARACTERIZATION of WHEAT FLOUR MILLING COPRODUCTS1,2

Hard red winter (HRW) and hard red spring (HRS) wheat milling coproducts (bran, germ, shorts, and red dog) from three commercial flour mills and the Kansas State University pilot mill were evaluated for differences in physical, chemical, and thermal properties. the ranges of bulk density for bran, germ, and red dog determined at three moisture levels were 146.5 to 205.2 kgm^?3, 269.2 to 400.6 kgm^?3, and 298.9 to 398.1 kgm^?3, respectively. the true density ranking order was: red dog >shorts = germ >bran, independently of the moisture level. Red dog had the smallest geometrical mean diameter with the highest variation (coefficient of variation of 23.8%). There was a significant (P < 0.05) difference among wheat blends and milling flows in the thickness of bran and germ at the same particle separation size. the image analysis study determined that the equivalent projected area diameter of bran at the same separation size was significantly (P < 0.05) larger than that of germ. the ratio between the equivalent projected area diameter and the particle thickness were within ranges of 15.7 to 37.6 for bran and 15.5 to 32.2 for germ particles. the chemical composition (ash, protein, lipids and fiber) ranges were determined for each coproduct. Ranges of thermal conductivity for bran, germ, shorts, and red dog were 0.049 to 0.074, 0.054 to 0.0907, 0.057 to 0.076, and 0.063 to 0.080 W(mK)^?1, respectively. Specific heat of coproducts, measured with a differential scanning calorimeter, exhibited a wider range [1.08–1.94 kJ(kgK)^?1] than that observed in whole wheat kernels and wheat flour. the variability observed among the samples was due to the different wheat sources and characteristic milling flows for the flour mills.     

粉末型五味子果醋生产工艺研究

以新鲜五味子为原料,对粉末醋制作工艺进行优化并对其产品质量进行分析。粉末醋制作工艺分为酒精发酵、醋酸发酵、果醋包埋、后熟以及喷雾干燥5个环节。通过单因素试验探讨酒精发酵工艺以及醋酸发酵工艺;通过响应面分析法优化果醋包埋条件和喷雾干燥条件。单因素试验结果表明,酒精发酵时果酱糖度调至13°Brix,醋酸发酵时醋酸菌接种量为10%时发酵效果较好;响应面分析结果表明,果醋包埋的最佳工艺条件为β-环糊精、卡拉胶以及藻胶钠的添加量分别为5.01%、0.63%、1.04%;喷雾干燥最佳工艺条件为进风量、进风温度以及进料速率分别为20.70 m^3/min,139.2℃以及499.6 mL/h。     

电力市场环境下的发电容量充裕性（二）几种现有方法的分析

鉴于单一能量市场模式难以确保发电容量充裕性,国际上已提出多种旨在解决该问题的方法。就设计思路、理论基础、实践经验和方法特点等方面,较系统地总结和分析了已提出的近似传统规划方法、容量费用模式、容量责任和装机容量模式、区域装机容量市场法、期权法、运行备用支付法和用户侧容量定购法等。对这些方法在理论上的优缺点和应用方面的可行性、适用范围、配套措施等阐明了观点,在此基础上对确保中国发电容量充裕性提出了初步建议。     

Fe-Mn-Si形状记忆合金在不同热机械循环条件下γ→ε马氏体相变的电子显微镜分析

测定了Ｆｅ３３７（ｗｔ）％Ｍｎ５２２（ｗｔ）％Ｓｉ形状记忆合金在不同变量和不同回复温度的热机械循环（简称“训练”）条件下的形状记忆效应（ＳＭＥ）。通过电子显微分析观察到应力诱发马氏体均为薄片层组织。在应变量过大或回复不充分的训练过程中，位错的增殖会破坏这种片层组织并影响晶体学的可逆性，同时使形状记忆效应恶化。