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61.
Xuezhi Zhang Ph.D. Andrejs Atrens Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1994,46(1):48-50
A boundary problem arising from rapid solidification with changing conditions at the moving boundary for the classical Stefan problem was solved by combining the heat transfer with crystallization kinetics using a front-tracking finite-difference scheme. At each time step, the conditions at the moving boundary were determined by an iterative process. 相似文献
62.
Y. C. Lee Ph.D. Nagesh Basavanhally Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1994,46(6):46-50
In addition to providing electrical connections, solder is useful in the formation of passive, precision alignments for optoelectronic packaging. Different designs have demonstrated micrometer-level alignment accuracies, and the aligned structures are becoming more and more complex. Solder engineering has been successfully introduced into the field of optoelectronics, and it is expected to be applied to many other areas demanding low-cost, precision alignments. 相似文献
63.
64.
T Tkebuchava LK von Segesser A Gallino O Dirsch MI Turina 《Canadian Metallurgical Quarterly》1997,38(3):457-462
1. The effect of the aqueous extract of Cissus sicyoides (CS) on isolated guinea pig aortic rings was studied. CS contracts the smooth muscle of the aorta in a dose-response relation. 2. The extract of CS increases the norepinephrine contraction in normal calcium and in solutions without calcium. 3. Lanthanum inhibits the contraction induced by CS. 4. The vasoconstrictor effect of CS was increased in solutions without calcium or with low calcium, which is an inverse calcium-dependent contraction. 5. Prolonged exposure to calcium-free solution did not abolish CS contraction. These contractions can be elicited repeatedly even after 6 hr of continuous exposure to calcium-free solutions. 6. Caffeine reduces contractile response induced by CS in normal calcium, as well as in solutions without calcium. 7. Our results support the idea that the aqueous extract of CS acts at the membrane level, increasing the calcium entry through the membrane as well as acting on the internal calcium deposits, possibly on the sarcoplasmic reticulum. 相似文献
65.
66.
M Flores-Díaz A Alape-Girón B Persson P Pollesello M Moos C von Eichel-Streiber M Thelestam I Florin 《Canadian Metallurgical Quarterly》1997,272(38):23784-23791
We previously isolated a mutant cell that is the only mammalian cell reported to have a persistently low level of UDP-glucose. In this work we obtained a spontaneous revertant whose UDP-glucose level lies between those found in the wild type and the mutant cell. The activity of UDP-glucose pyrophosphorylase (UDPG:PP), the enzyme that catalyzes the formation of UDP-glucose, was in the mutant 4% and in the revertant 56% of the activity found in the wild type cell. Sequence analysis of UDPG: PP cDNAs from the mutant cell showed one missense mutation, which changes amino acid residue 115 from glycine to aspartic acid. The substituted glycine is located within the largest stretch of strictly conserved residues among eukaryotic UDPG:PPs. The analysis of the cDNAs from the revertant cell indicated the presence of an equimolar mixture of the wild type and the mutated mRNAs, suggesting that the mutation has reverted in only one of the alleles. In summary, we demonstrate that the G115D substitution in the Chinese hamster UDPG:PP dramatically impairs its enzymatic activity, thereby causing cellular UDP-glucose deficiency. 相似文献
67.
Nachbarn kommt kein Mitspracherecht dahingehend zu, dass die Zufahrt für Einsatzfahrzeuge der Feuerwehr gew?hrleistet sein
müsste. 相似文献
68.
The development of a waste discharge charge system (WDCS) in South Africa has been proposed to promote waste reduction and water conservation. The WDCS is based on the polluter pays principle and is designed such that the management of waste discharges achieves resource quality objectives (RQOs) at the minimum total cost to the catchment. Two charges are distinguished: first a charge for optimising use of the resource (incentive charge); and secondly, a charge for development and operation of mitigation measures in the resource (mitigation charge). The WDCS is applied to both point sources and non-point sources (NPS) of contamination. In the inclusion of NPS, the charge system distinguishes between registered and non-registered NPS, with the charge applied to the former group only, in the first instance. This paper introduces the WDCS by describing the principles and the theoretical basis of the WDCS, highlighting the link to RQOs as the benchmark of acceptable externalities. The paper explores the inclusion of NPS in the WDCS, describing: first, the principles of NPS inclusion in the WDCS; secondly, the types of NPS included in the present version of the WDCS; thirdly, the methodology for charge estimation; and finally, non-registered NPS and their potential inclusion in future editions of the WDCS. The paper concludes with remarks and challenges facing the first edition of the WDCS. 相似文献
69.
70.
R. Bunk U. Leske R. Krompass Z. Pretch K. Rudolf R. Herbig K. Pitch V. A. Tsykanov O. V. Skiba V. A. Makarov L. P. Bol'shakov P. T. Porodnov A. A. Maershin S. S. Keruchen'ko 《Atomic Energy》1989,67(5):802-806
Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989. 相似文献