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直流电机及其控制系统出现故障时,它们的振动信号通常具有一些规律,表1列出了几种典型故障图谱(与正常状态图谱对照)。 1.无明显故障的直流电机的正常图谱 正常图谱是指对一台无故障正常运转的直流电机进行振动测试得出的振动图 相似文献
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为了实现西洋参配方颗粒全生产过程的质量控制,采用超高效液相色谱法(UPLC)对其饮片、标准汤剂和配方颗粒的指纹图谱和量质传递进行了相关性研究。采用UPLC法测定18批西洋参饮片、标准汤剂、3批配方颗粒的指纹图谱、人参皂苷Rg1,Re, Rb1总量,以K值和各已知成分的转移率作为量值传递的评价指标,结合相似度评价法研究三者的相关性。结果表明:西洋参饮片、标准汤剂、配方颗粒指纹图谱均呈现8个共有特征峰,并指认出5个成分,三者的指纹图谱与相应对照指纹图谱及三者对照指纹图谱的相似度均大于0.95,人参皂苷Rg1,Re, Rb1的转移率及K值趋势一致,量值传递稳定。西洋参饮片、标准汤剂、配方颗粒的化学成分基本一致,三者具有良好的相关性。研究所得可对西洋参配方颗粒的质量标准研究提供实验及理论支持,并为后续以标准汤剂为基准的配方颗粒或经典方制剂质量控制提供了参考依据。 相似文献
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为了使巴戟天配方颗粒的质量标准更加科学规范,通过对15批产自不同地区的巴戟天饮片进行标准汤剂的制备,以及对标准汤剂干膏粉进行研究,确定了巴戟天标准汤剂的出膏率范围;采用高效液相色谱法对主含成分耐斯糖进行了含量测定,研究了巴戟天配方颗粒的HPLC特征图谱分析方法,并对特征谱图中的水晶兰苷进行了指认。结果表明,在以流动相作为提取溶剂、甲醇-水(二者体积比为3∶97)为流动相的条件下,耐斯糖含量的转移率范围为73.21%~94.49%,标准汤剂出膏率范围为49.05%~55.87%。基于巴戟天配方颗粒的标准汤剂特征图谱研究方法严谨、可行,更加科学地阐明了配方颗粒与标准汤剂研究的一致性。 相似文献
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本文介绍了基于傅里叶变换红外光谱技术测定聚丙烯共聚物中乙烯含量的新方法。采集样品的红外光谱图,采用偏最小二乘法(PLS)建立光谱数据和样品中的乙烯含量的相关模型,应用所建模型对未知样品进行预测所建模型的回归系数,(R2)达到0.9959,校正均方根误差(RMSEC)为0.23。结论所建模型预测精确,可作为乙烯含量检测和在线质量监控的方法予以推广。 相似文献
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目的:制定参桂前列爽胶囊质量标准 方法:采用薄层色谱法对制剂中的桂枝、人参、甘草等进行TLC鉴别,采用HPLC对制剂中人参皂苷含量进行测定。结果:人参、桂枝、甘草供试品与对照品及对照药材色谱相应的位置上显相同颜色的斑点,阴性对照没有干扰。人参皂苷Rg1,Rc,Rb1在0.5-5μg范围内的线性良好(r〉0.999),平均回收率分别为100.2%、99.7%、100.3%。RSD分别为:2.13%、2.10%。结论:以上方法可以作为参桂前列爽胶囊的质量控制。 相似文献
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为了控制奥贝胆酸药品的质量,从奥贝胆酸原料药中分离并鉴定了3种有关物质:3α-羟基-6-乙基-7-酮-5β-胆烷-24-酸(A),3α,7α-二羟基-6-亚乙基-5β-胆烷-24-酸(B)和3α(3α,7α-二羟基-6α-乙基-5β-胆烷-24-酰基氧基)-7α-羟基-6α-乙基-5β-胆烷-24-酸(C)。分析了这些物质产生的原因并进行了设计合成,其结构经过核磁共振氢谱得以确认。研究表明,3个有关物质与奥贝胆酸粗品中的主要有关物质的相对保留时间完全一致,合成的有关物质与分离得到的有关物质的核磁共振氢谱图相符合,可以判定奥贝胆酸产品中的主要有关物质就是合成得到的有关物质A、有关物质B、有关物质C。解决了有关物质研究所需对照品的问题,提高了原料药的质量,为奥贝胆酸的质量研究和有关物质的控制提供了一定的帮助。 相似文献
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随着《北京市物流业调整和振兴实施方案》的实施,"纯电动物流车示范运营"项目的首批70辆电动车于近日开始了进行为期一年的示范运营,示范运营分别在北京新发地批发市场、神州泰岳良品电子商务有限公司、城市一百物流公司和北京烟草物流中心进行。这是新能源汽车首次在城市物流领域的规模化使用,也是继纯电动出租车和环 相似文献
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基于杯芳烃对分子的识别特性和量子点的高荧光特性,合成了脱叔丁基杯[6]芳烃的溶胶凝胶修饰二氧化硅包覆的碲化镉半导体纳米粒子,得到了新型的水溶性复合纳米粒子,并用1H NMR谱图、红外光谱、荧光光谱、紫外光谱、透射电镜进行了表征,并以新型的水溶性复合纳米粒子为荧光探针对客体分子乙二胺进行了识别和检测,使得乙二胺在5.0~150.0nmol·L-1范围内具有良好的线性关系,r=0.99913,最低检出限为5.70nmol·L-1。此荧光探针与客体分子乙二胺之间的相互作用,借以朗缪尔等温式加以解释,验证了新型的荧光探针对分子的识别具有高灵敏度、高荧光性、高选择性和高稳定性等优越特点。 相似文献
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为系统了解我国BIM技术的应用现状与发展方向,以中国知网(CNKI)收录的2017-2021年学术期刊中分析检索到的1137篇文献为数据源,运用文献计量可视化工具VOSviewer软件绘制知识图谱,对BIM技术相关研究文献的时序分布、核心作者、关键词密度、研究热点等进行科学系统地梳理,以期为今后BIM技术的深入研究提供参考。 相似文献
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Arup K. Mallik 《工程经济学家》2013,58(2):201-202
In his three recent papers [3], [4], and [5], R.G. Beaves develops an Overall Rate of Return (ORR) project evaluation criterion based on the concept of the so-called transition point (TP) which he has defined in two different versions.1 In the present contribution, it is shown that some projects may produce undefined ORRs for either TP version, and that other ORR-like criteria [7] may also generate undefined results for projects for which the Net Present Value (NPV) criterion is defined. To eliminate the cases of the ORR undefinability, a generalization of the ORR criterion is proposed that makes this criterion fully NPV compatible and applicable to both investment and financing projects. This criterion embraces all the existing ORR approaches that are based on the notions of the initial and terminal wealths, including both of Beaves' approaches. 相似文献
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闭路电视监控作为一项先进的高科技防范手段,特别是由于系统本身具有直观、实时、记录、回放等特点,在许多领域得到越来越广泛的应用。着重介绍了H.264视频压缩技术和视频网络传输技术的同时,对前端视频处理、传输系统设计、远程联网集中平台管理以及视频存储、转发与显示等全方面的纯数字高清网络视频监控系统进行了研究设计。 相似文献
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Market Power, Industrial Concentration and Innovative Activity 总被引:1,自引:0,他引:1
Robert W. Vossen 《Review of Industrial Organization》1999,15(4):367-378
This paper discusses the paradox between the positive effect of industrial concentration on R & D spending, and its non-positive effect on the number of innovations. Also, I analyze whether concentration has different effects on small- and large-firm R & D. The analysis shows that the positive effect of industrial concentration on R & D spending is at least as strong for small firms as it is for large firms within an industry, which indicates that the possession of market power is not in itself conducive to innovative effort. In addition, high concentration appears to be attended with a loss of efficiency in R & D spending. 相似文献
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本文从产业集聚引发的外部性出发,通过 EG 系数精确计算了中国 2000~2016 年中国 20 个制造类产业的集聚度,并构建联立方程组综合考察了产业集聚与环境污染间的关系,实证结果表明:(1)产业集聚与环境污染之间存在正U型关系,且当前绝大多数行业处于产业集聚系数转折点的左半段;(2)人均收入与环境污染间亦呈现环境库兹涅茨U型曲线,并且生活水平的提高能使人们有更强的意愿和投资来改善环境;(3)能源结构和能源强度对环境污染均有显著正影响,环境污染程度高的行业也是产业集聚度高的行业。因此应降低地方保护主义,促进企业专业化生产和鼓励各地区分工协作,改善能源消费结构和提高能源利用效率,从而优化产业结构以实现经济的可持续发展。 相似文献
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Mark Paul Gius 《Review of Industrial Organization》1993,8(5):599-608
The objectives of this study are to determine the extent of the market in a differentiated-product industry and to evaluate a technique developed by Schmalensee (1985) that tests for generalized rivalry. A market is defined as a product spectrum along which generalized rivalry exists. The industry chosen for study is the liquor industry. Results of this study indicate that the liquor industry consists of three markets and that Schmalensee's technique has several limitations that must be acknowledged when interpreting results.I would like to thank Jon P. Nelson, Mark Roberts, Ed Sexton, and Dave Ribar for their helpful comments. I would also like to thank Heidi Applegate, Timothy Hylan, Joyce Mlakar, and my parents for their support and encouragement. 相似文献
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The life cycle model has become part of the everyday vocabulary of management and is used as a rough simplification of rather complex phenomena. Chris DeBresson and Joseph Lampel have undertaken a thorough re-examination of the underlying assumptions of the model and propose a reformulation that they believe gives a better approximation of the dynamics of technological and organizational change. The basis for their reformulation is a survey of 4000 British and Canadian innovations in many industries over some 30 years.
In a companion article immediately following this one, the authors illustrate their reformulation by a detailed analysis of one firm in one industry. 相似文献
In a companion article immediately following this one, the authors illustrate their reformulation by a detailed analysis of one firm in one industry. 相似文献
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Y. Cartonnet 《International Journal of Technology and Design Education》1999,9(2):153-172
This study examines the influence of two crossed factors upon the performance of a subject whose aim is to understand the functioning of a complex piece of technical apparatus, in this instance an automated arm from an assembly line. The primary factor was the encoding degree of the third dimension which constitutes the representation of the object. The methods of presentation were: a 3-D photograph, an axonometric perspective drawing and a first angle orthographic drawing. The second factor was professional experience. The subjects were, on the one hand, first year technology pupils (15--16 year-olds) and, on the other hand, professional draughtsmen from RENAULT. The results obtained with the 3-D photograph were twice as good as those obtained with the axonometric perspective or the orthographic drawing. It should be pointed out that experience did not effect the score. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献