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991.
L. N. Lai    A. A. Karim    M. H. Norziah    C. C. Seow 《Journal of food science》2004,69(4):FCT249-FCT25
ABSTRACT: Using a Rapid Visco Analyzer (RVA), it was revealed that 2 alkalizing agents (Na2CO3 and NaOH) had a far larger effect on pasting properties of nonwaxy starches (wheat, corn, rice) compared with their effect on waxy starches (waxy corn and waxy rice). It was hypothesized that the alkalizing agents have a greater propensity to attack the amorphous regions of the nonwaxy starch granules, thereby causing increased leaching of amylose molecules and possibly also some hydrolysis of starch chains. As a result, the RVA pasting profile of a nonwaxy starch, in the presence of alkali, was drastically altered to one that more closely resembled that of its waxy counterpart without added alkali.  相似文献   
992.
In this paper, we present a robust image alignment algorithm based on matching of relative gradient maps. This algorithm consists of two stages; namely, a learning-based approximate pattern search and an iterative energy-minimization procedure for matching relative image gradient. The first stage finds some candidate poses of the pattern from the image through a fast nearest-neighbor search of the best match of the relative gradient features computed from training database of feature vectors, which are obtained from the synthesis of the geometrically transformed template image with the transformation parameters uniformly sampled from a given transformation parameter space. Subsequently, the candidate poses are further verified and refined by matching the relative gradient images through an iterative energy- minimization procedure. This approach based on the matching of relative gradients is robust against nonuniform illumination variations. Experimental results on both simulated and real images are shown to demonstrate superior efficiency and robustness of the proposed algorithm over the conventional normalized correlation method.  相似文献   
993.
为了改进HDT-55转台过滤机使用中暴露出的布料布水槽角度不合理、栈桥及支架腐蚀严重、滤布冲洗水喷头易堵、钢衬胶真空环形管易起泡等问题,采取了如下措施:将布水、布料槽顺时针转10~15°,增加吸气室空间,改进滤布冲洗喷头总成,改进环形管材质等.实施后,磷石膏达到含水质量分数<30%,过滤现场气雾下降,滤布冲洗喷头使用时间延长,消除了环形管腐蚀和堵管现象.  相似文献   
994.
网络技术目前已逐步成为现代信息技术的主流,网络的概念也随着Internet技术的应用和发展而渐入到社会的各个行业和领域,而在制造业中的表现尤为突出。因此,开展基于Web的远程数控服务对于企业来说具有重要的现实意义。研究了基于Web的数控远程支持服务平台的总体结构和模块功能,并重点介绍了其数据库的设计,最后给出了详细的系统运行实例。  相似文献   
995.
This letter investigated the reproducible bistable resistance switching characteristics of a single-layer organic device based on 8-hydroquinoline aluminum (Alq3) fabricated by spin coating. By controlling the ON-state current through the Alq3 films, it has been possible to achieve various resistance states of the films. In addition, the resistance of the ON-state Alq3 films also affects the threshold current and voltage to switch off the device. The independence of the current-injected direction to erase the ON state implies that the filament theory could elucidate the observed phenomenon. The ratio between low- and high-resistance states can reach five orders of magnitude, which will be a potential material for nonvolatile memory application.  相似文献   
996.
Originally purified as a major lipid component of a strain of the cyanobacterium Lyngbya majuscula isolated in Cura?ao, curacin A is a potent inhibitor of cell growth and mitosis, binding rapidly and tightly at the colchicine site of tubulin. Because its molecular structure differs so greatly from that of colchicine and other colchicine site inhibitors, we prepared a series of curacin A analogs to determine the important structural features of the molecule. These modifications include reduction and E-to-Z transitions of the olefinic bonds in the 14-carbon side chain of the molecule; disruption of and configurational changes in the cyclopropyl moiety; disruption, oxidation, and configurational reversal in the thiazoline moiety; configurational reversal and substituent modifications at C13; and demethylation at C10. Inhibitory effects on tubulin assembly, the binding of colchicine to tubulin, and the growth of MCF-7 human breast carcinoma cells were examined. The most important portions of curacin A required for its interaction with tubulin seem to be the thiazoline ring and the side chain at least through C4, the portion of the side chain including the C9-C10 olefinic bond, and the C10 methyl group. Only two modifications totally eliminated the tubulin-drug interaction. The inactive compounds were a segment containing most of the side chain, including its two substituents, and analogs in which the methyl group at the C13 oxygen atom was replaced by a benzoate residue. Antiproliferative activity comparable with that observed with curacin A was only reproduced in compounds that were potent inhibitors of the binding of colchicine to tubulin. Molecular modeling and quantitative structure-activity relationship studies demonstrated that most active analogs overlapped extensively with curacin A but failed to provide an explanation for the apparent structural analogy between curacin A and colchicine.  相似文献   
997.
A discrete replacement model for a repairable system which is subject to shocks and minimal repairs is discussed. Such shocks can be classified, depending on its effect to the system, into two types: Type I and Type II shocks. Whenever a type II shock occurs causes the system to go into failure, such a failure is called type II failure and can be corrected by a minimal repair. A type I shock does damage to the system in the sense that it increases the failure rate by a certain amount and the failure rate also increases with age due to aging process without external shocks; furthermore, the failure occurred in this condition is called type I failure. The system is replaced at the time of the first type I failure or the n-th type Il failure, whichever occurs first. Introducing costs due to replacement and mininal repairs, the long-run expected cost per unit time is derived as a criterion of optimality and the optimal number n∗ found by minimizing that cost. It is shown that, under certain conditions, there exists a finite and unique optimal number n∗.  相似文献   
998.
短时间、大功率磁流体发电   总被引:3,自引:0,他引:3  
介绍了正在发展中的、以炸药或燃烧驱动的等离子体为工质的短时间、大功率磁流体(MHD)发电系统。这是一种脉冲发电系统,可提供几百兆瓦或更高的脉冲功率;也是一种利用电能的新概念火炮的合适能源,具有广阔的军事应用前景。文中还介绍了磁流体发电的基本原理;结合国外的发展现状、动态和我们做过的有关工作,对研制这种脉冲发电系统将会碰到的部分问题作出了评述。  相似文献   
999.
1000.
介绍了灯饰横梁零件成形工作过程及工艺过程,对灯饰横梁零件压形整形复合模作了较详细介绍,对生产类似产品的厂家有一定的参考应用价值。  相似文献   
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