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排序方式: 共有4166条查询结果,搜索用时 15 毫秒
41.
Gijs Werner 《世界电子元器件》2010,(8):46-47
随着众多国家政府积极推动LED照明的开发与实现,LED元件和引擎成了电子行业的一大增长领域,预计今后5年内市场增长率CAGR将达到20%。像FCI这样的互联企业会紧跟这些发展趋势以便确定如何扩大或加强其产品线,进而支持未来的LED技术,也就不足为奇了。 相似文献
42.
M.Vinogradski U.Werner B.Orlik 《电力电子》2005,3(3):35-39
在制造横向磁场永磁电机(TFPM)电机之前,应确定最大转矩的波形。通过调整TFPM电机的各项几何参数,可以使电机达到其最大转矩。一种基于人工智能的最优化方法可以使得每个极间隔都获得理想的转矩波形。本文给出了一种用于优化TFPM几何参数的遗传算法,该算法同样适用于其它结构的电机。 相似文献
43.
Setton E. Taesang Yoo Xiaoqing Zhu Goldsmith A. Girod B. 《Wireless Communications, IEEE》2005,12(4):59-65
Cross-layer design breaks away from traditional network design where each layer of the protocol stack operates independently. We explore the potential synergies of exchanging information between different layers to support real-time video streaming. In this new approach information is exchanged between different layers of the protocol stack, and end-to-end performance is optimized by adapting to this information at each protocol layer. We discuss key parameters used in the cross-layer information exchange along with the associated cross-layer adaptation. Substantial performance gains through this cross-layer design are demonstrated for video streaming. 相似文献
44.
D. N. Lobanov A. V. Novikov K. E. Kudryavtsev M. V. Shaleev D. V. Shengurov Z. F. Krasilnik N. D. Zakharov P. Werner 《Semiconductors》2012,46(11):1418-1422
The results of investigation of the electroluminescence of multilayer p-i-n structures with Ge(Si)/Si(001) self-assembled islands are presented. The nonmonotonic dependence of the room-temperature intensity of the electroluminescence signal from islands on the Si spacer thickness is revealed. The highest electroluminescence signal intensity is observed for structures with a Si spacer thickness of 15?C20 nm. The significant decrease detected in the electroluminescence signal from the islands in structures with thick Si spacers (>20 nm) is explained by the formation of defect regions in them. The observed decrease in the electroluminescence signal in structures with thin Si layers is associated with a decrease in the Ge fraction in the islands in these structures, which is caused by enhanced Si diffusion into islands with increasing elastic strains in the structure. 相似文献
45.
Werner Heimann und Ulla Timm 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1977,165(1):12-14
Zusammenfassung Hydroperoxid-Isomerase aus Gerste wurde mit Linolsdurehydroperoxiden (LHPO) incubiert, welche überwiegend das 13-LHPOoder das 9-LHPO-Isomere enthielten; die dabei entstehenden flüchtigen Produkte wurden isoliert, angereichert und gas- sowie radiogaschromatographisch untersucht. Dadurch war es möglich, die Vorldufer der flüchtigen Carbonylverbindungen Hexanal, 2-trans-Heptenal und 2-trans-Octenal zu ermitteln, die aus früher beschriebenen Reaktionen von Isomerase mit etwa gleichprozentiger 9- zu 13-LHPO-Substratlösung hervorgegangen waren. Als Vorläufer von Hexanal und 2-tr-Octenal wurde das 13-LHPO ermittelt, während das 9-LHPO-Isomere bei der Gerstenisomerase-LHPO-Abbaureaktion anscheinend nicht als Vorläufer flüchtiger Verbindungen in Frage kommt. — Nicht geklärt werden konnte die Herkunft des 2-tr-Heptenals, da es weder bei den Versuchen mit uberwiegend 9-LHPO noch bei denen mit uberwiegend 13-LHPO auftrat. Möglicherweise entsteht 2-tr-Heptenal nur bei einem bestimmten Mengenverhdltnis beider Hydroperoxid-Isomeren.
Abbreviations 13-LHPO 13-hydroperoxy-9-cis,1[-trans-octadecadienoic acid - 9-LHPO 9-hydroperoxy-10-trans, 12-cis-octadecadienoic acid Abkürzungen 13-LHPO 13-Hydroperoxy-9-cis,11-trans-octadecadiensdure - 9-LHPO 9-Hydroperoxy-10-trans,12-cis-octadeca-diensäure Unser Dank gilt der AIF and dem Forschungskreis der Ernährungsindustrie für die finanzielle Unterstützung der Arbeit. Herrn Dir. F. Ruf, Maizena Geselischaft m. b. H., danken wir ffürr wertvolle Anregungen and Förderung dieser Arbeit 相似文献
Carbonyl compounds from the reaction of barley isomerase with linoleic acid hydroperoxides. Their development from the 9- or the 13-hydroperoxide-isomer
Summary Hydroperoxid isomerase from barley was incubated with linoleic acid hydroperoxides (LHPO), containing nearly exclusively the 13-LHPO or the 9-LHPO isomer; the volatile reaction products were isolated, concentrated and investigated by means of gas and radio-gaschromatography. Thus it was possible to establish the precursors of the volatile compounds hexanal, 2-trans-heptenal and 2-trans-octenal, which develop during formerly described reactions of isomerase with substrates, containing 9- and 13-LHPO in equal, amounts. 13-LHPO was found to be a precursor of hexanal and 2-tr-octenal, while the 9-LHPO isomer in the barley isomerase LHPO breakdown reaction obviously cannot be accepted as precursor of volatile components. The origin of 2-tr-heptenal could not be clarified; it occured neither in the experiments with predominating 9-LHPO nor in those with predominating 13-LHPO. — Perhaps 2-tr-heptenal is only produced in the presence of a defined ratio of both isomeric hydroperoxides
Abbreviations 13-LHPO 13-hydroperoxy-9-cis,1[-trans-octadecadienoic acid - 9-LHPO 9-hydroperoxy-10-trans, 12-cis-octadecadienoic acid Abkürzungen 13-LHPO 13-Hydroperoxy-9-cis,11-trans-octadecadiensdure - 9-LHPO 9-Hydroperoxy-10-trans,12-cis-octadeca-diensäure Unser Dank gilt der AIF and dem Forschungskreis der Ernährungsindustrie für die finanzielle Unterstützung der Arbeit. Herrn Dir. F. Ruf, Maizena Geselischaft m. b. H., danken wir ffürr wertvolle Anregungen and Förderung dieser Arbeit 相似文献
46.
Werner Heimann und Verena Klaiber 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1977,165(3):131-136
Zusammenfassung Die Untersuchung einer aus Roggen gewonnenen Lipoxygenase-aktiven Enzymfraktion ergab, daß Roggenlipoxygenase ein Molekulargewicht von ca. 102000 besitzt. Bei der isoelektrischen Fokussierung traten zwei Bandengruppen mit isoelektrischen Punkten zwischen 5,1–5,5 und 5,8–6,4 auf. Durch Ionenaustauschchromatographie konnten drei Isoenzyme gewonnen werden. Das pH-Optimum der Umsetzung lag bei 7,3–7,5. Roggenlipoxygenase katalysiert vorwiegend die Bildung von 13-Hydroperoxy-9-cis,11-trans-octadecadiensäure (13-LHPO). Durch eine hochmolekulare Proteinfraktion wurden in Roggen die LHPO zu a-Ketolen umgesetzt. Diese Roggenisomerase setzt die von der systemeigenen Lipoxygenase gebildeten LHPO zu überwiegend 12,13-Ketohydroxysduren um. Roggenisomerase hat eine Michaeliskonstante von 3–5 × 10–5, (LHPO). Die Reaktionsgeschwindigkeit der Umsetzung stieg bei kleinen Proteinkonzentrationen linear mit der Proteinkonzentration.
On lipoxygenase and enzymes which decompose linoleic acid hydroperoxides in rye
Summary An enzyme fraction from rye containing lipoxygenase activity was investigated. The molecular weight of lipoxygenase was found to be about 102000. Two bands groups with isoelectric points between 5.1–5.5 and 5.8–6.4 were obtained by isoelectric focusing. Three isoenzymes could be separated by ion exchange chromatography. Lipoxygenase has optimum activity at pH 7.3–7.5 and predominantly forms 13-hydroperoxy-9-cis,11-trans-octadecadienoic acid (13-LHPO).In rye the 13-LHPO is converted to -ketols by a high molecular protein fraction. This isomerase converts the LHPO formed by rye lipoxygenase predominantly to 12,13-ketohydroxy acids. The Michaelis Constant of isomerase is 3–5 × 10–5, using LHPO as substrate. At low protein concentrations the reaction velocity of LHPO-conversion increases linearly with protein concentration.相似文献
47.
Werner J. Hexamer M. Meine M. Lemke B. 《IEEE transactions on bio-medical engineering》1999,46(9):1057-1064
In the past, the development of rate-adaptive (sensor-controlled) pacemaker systems seems to have been determined primarily by the availability, compatibility and other properties of the technical sensor. This paper, however, focuses on the system-physiological aspect in an attempt to answer the question to what extent physiological cardiovascular control is restored by the pacemaker system. This is a question which should be asked before attempting to design a sensor-controlled system and especially before designing multisensor systems with infinite combinations. Four categories are defined: direct bridging ("shunting"), open loop systems, closed systems using cardiorespiratory or metabolic coupling and those using cardiac signals. Further subdivisions are shown. From the bioengineering as well as from the physiological viewpoint a system should preferably not combine sensors from one and the same of these categories. At present direct bridging is available only for the atrioventricular (AV)-block, so that for sick-sinus-syndrome (SSS) patients feedback control via cardiac signals ("inotropic" pacemaker) comes nearest the goal without, however, ideally bridging the gap. Open-loop systems should no longer be developed as single-sensor systems. A well developed activity sensor, however, which quickly pinpoints the most prominent stressor of cardiovascular control is best suited to complement another sensory system achieving closed-loop control. New and promising concepts orientated toward direct bridging are the analysis of monophasic action potentials and the "dromotropic" concept, both of which seek direct correlation with the "chronotropic" information not available in SSS patients. 相似文献
48.
A fractal is a recursively generated object having a fractional dimension. Many objects, including antennas, can be designed using the recursive nature of a fractal. In this article, we provide a comprehensive overview of recent developments in the field of fractal antenna engineering, with particular emphasis placed on the theory and design of fractal arrays. We introduce some important properties of fractal arrays, including the frequency-independent multi-band characteristics, schemes for realizing low-sidelobe designs, systematic approaches to thinning, and the ability to develop rapid beam-forming algorithms by exploiting the recursive nature of fractals. These arrays have fractional dimensions that are found from the generating subarray used to recursively create the fractal array. Our research is in its infancy, but the results so far are intriguing, and may have future practical applications 相似文献
49.
50.
An on-chip electroosmotic (EO) micropump (EOP) was integrated in a microfluidic channel combined with a light-addressable potentiometric sensor (LAPS). The movement of EO flow towards right and left directions can be clearly observed in the microfluidic channel. The characteristics of photocurrent-time and photocurrent-bias voltage are obtained when buffer solution passes through the sensing region. The results demonstrate that the combination of an on-chip EOP with an LAPS is feasible. 相似文献