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排序方式: 共有176条查询结果,搜索用时 15 毫秒
171.
This paper discusses an algorithm for generalized convex multiplicative programming problems, a special class of nonconvex minimization problems in which the objective function is expressed as a sum ofp products of two convex functions. It is shown that this problem can be reduced to a concave minimization problem with only 2p variables. An outer approximation algorithm is proposed for solving the resulting problem. 相似文献
172.
Niklaus Hriger Dobrila
ivanov Horst H. A. Linde Kuno Meyer 《Helvetica chimica acta》1970,53(8):2051-2059
From the toad venom Ch'an Su digitoxigenin (I), periplogenin (IX), and sarmentogenin (XI) were isolated as well as the two new 14, 15 β-epoxy-cardenolides III and VI which — regarding their steroid nucleus — are corresponding to cinobufotalin and marinobufagin, respectively. 相似文献
173.
Kuno Lorenz 《Archive for Mathematical Logic》1968,11(3-4):73-100
Ohne ZusammenfassungEs handelt sich um eine Fortsetzung von Teil I in Band 11 dieser Zeitschrift, pp. 32–55. 相似文献
174.
175.
Single-molecule optical experiments carried out in conjunction with externally applied electric fields show deliberate spatial and intensity control over CdSe nanowire (NW) emission. In particular, by applying external fields to electrically isolated (single) NWs, their emission can be localized in areas of the wire closest to the positive electrode. In a few cases, the resulting emission intensity increases over the corresponding zero-field value by nearly an order of magnitude. More often than not, factors of 2-3 are seen. Reversing the field polarity causes the emission to localize in opposite regions of the wire. Emission from individual NWs can therefore be modulated. Complementary ac electric field measurements show that the effect persists up to 500 kHz. To explain the phenomenon, the effective passivation of surface trap states by mobile carriers is speculated. This, in turn, causes local changes in the NW emission quantum yield (QY). To verify the presence of such mobile charges, both ensemble and single NW bundle electrophoresis experiments are conducted. By investigating subsequent NW rotational and translational dynamics, an estimate for the number of mobile carriers is determined. A lower limit (best case) linear charge density of approximately 0.45-1.2 mobile electrons per micrometer of the wire is obtained. Apart from self-consistently explaining the field-induced NW emission modulation, the resulting data and subsequent analysis also suggests that the same mobile carriers may be the root cause of NW emission intermittency. Furthermore, given the ubiquity of stray charges, the resulting hypothesis may have additional applicability toward explaining blinking in other systems, a problem of current interest especially within the context of colloidal QDs. 相似文献
176.
Sybille Hopman Kuno Mayer Andreas Fell Matthias Mesec Filip Granek 《Applied Physics A: Materials Science & Processing》2011,102(3):621-627
In this paper results for liquid media are presented, which are used the first time as liquid jet for cutting of silicon with
laser chemical processing (LCP). The liquids contain a perfluoro-carbon compound as solvent and elemental chlorine as etching
agent for silicon. Experiments were performed to investigate its influence on groove form and maximum achieved groove depth.
It is shown that with the addition of low-concentration chlorine, the groove depth can already be significantly increased.
The groove shape could be changed from a V-profile to a U-profile. Furthermore, an about four times greater groove depth was
achieved by applying a saturated chlorine solution compared to groove depths without using chlorine. Finally, a theory is
given and discussed to describe the phenomena observed. 相似文献