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。     

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.     

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.     

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.     

Application of glyph-based techniques for multivariate engineering visualization

This article presents a review of glyph-based techniques for engineering visualization as well as practical application for the multivariate visualization process. Two glyph techniques, Chernoff faces and star glyphs, uncommonly used in engineering practice, are described, applied to the selected data set, run through the chosen optimization methods and user evaluated. As an example of how these techniques function, a set of data for the optimization of a heat exchanger with a microchannel coil is adopted for visualization. The results acquired by the chosen visualization techniques are related to the results of optimization carried out by the response surface method and compared with the results of user evaluation. Based on the data set from engineering research and practice, the advantages and disadvantages of these techniques for engineering visualization are identified and discussed.     

Star‐shaped amphiphilic block polyurethane with pentaerythritol core for a hydrophobic drug delivery carrier

To obtain polyurethane micelles with excellent stability as a drug delivery carrier, star‐shaped amphiphilic block polyurethane (SAPU) was successfully synthesized by the ‘arm‐first’ method, using methoxypoly(ethylene glycol) and poly(ε‐caprolactone) diol as soft segments, hexamethylene diisocyanate as hard segments and pentaerythritol as the core. The structure of the SAPU was characterized by Fourier transform infrared spectroscopy, ¹H NMR spectroscopy and gel permeation chromatography. The micellization behaviour and micelle properties of SAPU were measured by the pyrene fluorescence probe technique, ¹H NMR, SEM and dynamic light scattering. The results indicated that SAPU could self‐assemble to form nanomicelles in aqueous solution and that the micelles showed excellent stability upon dilution and storage. Indometacin as a model drug could be incorporated into SAPU micelles and be released sustainedly. Meanwhile, the hydrophilic segment content and the molecular weight of SAPU had effects on the micelle properties. In addition, SAPU exhibited good cytocompatibility estimated by methylthiazole‐tetrazolium assay. © 2016 Society of Chemical Industry     

星形聚乙二醇-聚乳酸嵌段共聚物的合成与表征

以不同臂数和分子量的星型聚乙二醇(sPEG)和L-丙交酯为原料,采用开环聚合法合成了以星型聚乙二醇为内部嵌段、聚L-乳酸为外部嵌段的多臂星形聚乙二醇-聚乳酸嵌段共聚物(sPEG-b-PLLA)。研究了sPEG的臂数、分子量及L-丙交酯/sPEG投料比等参数对产物结构与性能的影响。并分别用红外光谱(FT-IR)、核磁共振(1H-NMR)、凝胶渗透色谱(GPC)、差示扫描量热(DSC)对产物进行了表征,证实所合成的嵌段共聚物具有预期的结构。结果表明,sPEG-b-PLLA为结晶性聚合物,且表现出与PLLA相似的晶型,随着PLLA链段的增加,产物的结晶度也呈增大的趋势;与PLLA相比,sPEG-b-PLLA的接触角随着PEG链段的增多而增大,表明其亲水性明显改善。     

CMOS星敏感器焦平面装配及标定

针对高精度CMOS星敏感器的使用要求,本文对焦平面装配的误差进行了理论分析,搭建了CMOS星敏感器装配及标定测试系统,利用长焦距平行光管像面移动测量方法进行了星敏感器轴上和轴外的星点成像,获取了焦平面离焦量及倾斜数据.在这些数据指导下,成功完成了对某焦距50 mm,相对孔径1/1.25,全视场20°的CMOS星敏感器的...     

星状聚(N-异丙基丙烯酰胺)的合成及性能研究

采用2-溴异丁酰溴与β-环糊精(-βCD)上羟基的适度反应得到了多溴代的-βCD(Br-βCD)。用Br-βCD引发N-异丙基丙烯酰胺(NIPAm)发生原子转移自由基聚合(ATRP),合成出约15臂的聚(N-异丙基丙烯酰胺)星状聚合物-βCD-(PNIPAm)15.4。用IR1、H-NMR表征了星状聚合物的结构,以8-苯胺基-1-萘磺酸(ANS)作客体分子,研究了星状聚合物的包合性,结果表明,-βCD-(PNIPAm)15.4具有热敏性和超分子包合性。