一种新的全天自主几何结构星图识别算法

提出了一种新的星图识别算法,该算法根据星敏感器的观测精度,在识别前去除星三角形的观测误差,对无误差的星三角形进行编码,构造特征量。导航三角形的识别只需基于单一特征量的匹配就可完成。多三角形的组合,有效地提高了正确识别率。仿真实验表明,该算法与传统的三角形算法相比,具有更好的实时性和鲁棒性。     

分散控制系统网络的技术改进

以彭城发电厂MAX1000分散控制系统网络结构为例，介绍其存在的问题以及技术改进情况。通过采用以太网星形结构的网络连接方式，将分散控制系统由总线形网络拓朴结构改为星形网络拓扑结构。实践表明，改进后彭城发电厂MAX1000分散控制系统网络的安全性得到了提高，MIS系统网络的可靠性也得以改善。     

基于高精度星敏感器的船载雷达海上精度鉴定

航天测量船海上航行时主要通过精度校飞进行雷达精度鉴定,针对其周期长、耗费大和组织协调困难的缺点,提出了一种采用高精度星敏感器与雷达捷联跟踪测量空间目标进行海上精度鉴定的方法。雷达在跟踪空间目标的同时,星敏感器实时拍摄天线指向附近星图。首先,星敏感器利用雷达输出的编码器角度计算视轴的初始指向,通过快速星图识别和目标定位获取天线地心坐标系精确指向;然后,经坐标变换到地平系,根据蒙气差模型修正地平系俯仰角,再经过船摇修正转换到甲板坐标系;最后,进行轴系误差及脱靶量修正,实现雷达指向精度鉴定。试验结果表明:利用该方法测量的船载雷达相对于星敏感器方位、俯仰随机残差优于50″,满足雷达精度鉴定要求,证明该方法的可行性。     

Star graft copolymer via grafting‐onto strategy using a comb!ination of reversible addition–fragmentation chain transfer arm‐first technique and aldehyde–aminooxy click reaction

A facile synthetic pathway to a multi‐arm star graft polymer has been developed via a grafting‐onto strategy using a combination of a reversible addition–fragmentation chain transfer (RAFT) arm‐first technique and aldehyde–aminooxy click reaction. A star backbone bearing aldehyde groups was prepared by the RAFT copolymerization of acrolein (Ac), an existing commercial aldehyde‐bearing monomer, with styrene (St), followed by crosslinking of the resultant poly(St‐co‐Ac) macro‐RAFT agent using divinylbenzene. The aldehyde groups on the star backbone were then used as clickable sites to attach poly(ethylene glycol) (PEG) side chains via the click reaction between the aldehyde groups and aminooxy‐terminated PEG, leading to a structurally well‐defined star graft copolymer with arms consisting of poly(St‐co‐Ac) as backbone and PEG as side chains. Crystalline morphology and self‐assembly in water of the obtained star graft copolymer were also investigated. Opportunities are open for the star graft copolymer to form either multimolecular micelles or unimolecular micelles via control of the number of grafted PEG side chains. © 2013 Society of Chemical Industry     

Assessment of organic acid-rich bio-sap to generate electricity

The study has focused on electricity generation from organic acid-rich bio-substrate like star fruit (Averrhoa carambola). The sap of star fruit was selected as an electrolyte due to the presence of significant amounts of organic acids such as citric acid and ascorbic acid. To preserve the sap, 2% phenol by volume was used to reduce the growth of microorganisms, and the addition of phenol did not affect the initial pH. It was observed that due to an increase in the electrode surface area, reaction rate and current generation had been amplified. Internal resistance also decreased rapidly because of the large electrode surface area. Furthermore, internal resistance was the significant barrier in electricity generation, which was also successfully controlled by the baffle flow agitation system. Moreover, the baffle flow agitation system reduces the formation of dead zones and increases the total dissolved solids inside the electrochemical cell compartments during operation.     

Star graph automorphisms and disjoint Hamilton cycles

The search for edge-disjoint Hamilton cycles in star graphs is important for the design of interconnection network topologies. We define automorphisms for star graphs St _n of degree n?1, for every positive odd integer n, which yield permutations of labels for the edges of St _n taken from the set of integers between 1 and ? n/2 ?. By decomposing these permutations into permutation cycles, we are able to identify edge-disjoint Hamilton cycles that are automorphic images of a known Hamilton cycle in St _n . Our method produces a better than two-fold improvement from ? ? (n)/10 ? to ? 2? (n)/9 ?, where ? is the Euler function, for the known number of edge-disjoint Hamilton cycles in St _n for all odd integers n. For prime n, the improvement is from ? n/8 ? to ? n/5 ?, and we can extend this result to the case when n is the power of a prime greater than 7.     

Magnetized strange quark matter in the equivparticle model with both confinement and perturbative interactions

We investigated the properties of strange quark matter in an external strong magnetic field with both confinement and leading-order perturbative interactions considered. It was found that the leading-order perturbative interaction can stiffen the equation of state of magnetized quark matter, while the magnetic field lowers the minimum energy per baryon. By solving the Tolman–Oppenheimer–Volkoff equations, we obtain the internal structure of strange stars. The maximum mass of strange stars can be as large as 2 times the solar mass.     

Synthesis of polylactide‐based thermoset resin and its curing kinetics

A new class of biobased thermoset resins, methacrylated four‐armed star‐shaped polylactides (M4sPLAs), was prepared. The effect of star architecture, e.g. varying arm length, on the properties of the cured products was examined. Based on differential scanning calorimetry, the non‐isothermal and isothermal curing behaviors of these M4sPLAs were investigated. Various curing kinetic parameters were obtained and elucidated using autocatalytic reaction models. Experimental results indicate that the oligomers can be crosslinked into a rigid network within a curing time varying from several minutes to more than an hour upon thermal initiation. The curing processes of M4sPLAs with varying arm length are different and complex, as indicated by the change of various kinetic parameters, reaction orders and evolutions of activation energy under the test reaction conditions. High crosslinking density is especially effective for improving the thermal stability of polylactide, but also leads to slower degradation rate and deterioration of its impact properties. Copyright © 2012 Society of Chemical Industry     

An Energy-efficient Switching Scheme with Reduced Switching Transients for a Wind-driven Induction Generator

This article presents a scheme for improving the power output of grid-connected induction generator commonly used in wind energy conversion systems. Generally, the stator of the induction generator is connected in a star with a line voltage of √3 times the rated winding voltage to reduce the line current and, hence, conductor size. To extend the generating operation over a wider speed range, delta-star switchable stator windings are also in vogue. In such cases, the stator is star connected in the lower speed range and switched to a delta connection above a threshold speed. In this study, a new switching scheme is proposed wherein the stator coils are always connected in a star, while the stator is connected to different voltages in low- and high-speed conditions. At low wind speeds, nominal winding voltage is applied to the stator, whereas at higher speeds, the stator applied voltage is √3 times higher than the rated winding voltage. The efficacy of the scheme is demonstrated experimentally with a suitable microcontroller-based switching arrangement. Typical results indicate an increase in output with reduced switching transients. A case study on a 3-Φ, 50-kW induction generator is presented to emphasize the performance improvement with the proposed scheme.     

浅析改善电控组合泵柴油机冷起动冒烟的途径

主要是以电控组合泵柴油发动机为例,介绍了影响电控组合泵柴油机的冷起动冒烟的主要因素及改善方法。