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991.
Günter Matthi 《Microelectronics Reliability》1991,31(5)
The model is considered in more detail than in Part I of the series, and is verified by results of laboratory tests on humidity absorption and plastication with respect to material analysis and degradation of bipolar transistors with respect to several electric characteristics of temperature-humidity bias. The results confirm the model very well. They allow derivation of methods to increase the reliability of microelectronic devices, and selection of tests and test conditions. 相似文献
992.
993.
Mechanical properties of a modified acrylic bone cement with etoxytriethyleneglycol monomethacrylate
B. Pascual M. Gurruchaga I. Goñi M. P. Ginebra F. J. Gil J. A. Planell B. Levenfeld B. Vázquez J. San Román 《Journal of materials science. Materials in medicine》1995,6(12):793-798
With the aim of improving some of the disadvantages of the acrylic bone cements, an acrylic bone cement based on polymethyl methacrylate has been modified by substituting different quantities, up to 20%, of the monomer methyl methacrylate (MMA) with the same amount of ethoxytriethyleneglycol monomethacrylate (TEG). The addition of this new monomer decreased noticeably the maximum temperature and increased both setting and working times. Mechanical testing revealed that the introduction of TEG gave rise to a less fragile bone cement by increasing slightly the total deformation without any change in the rest of the tensile parameters. 相似文献
994.
Bla?enka ?ebe?i? Irena Vedrina-Dragojevi? 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1992,194(2):144-147
Summary The simple fluorometric method for determination of added pyridoxine-HCl in enriched food, based on oxidation of pyridoxine to 4-pyridoxic acid by means of KMnO4, has been modified for determination of total B6 in soya bean. In comparison to the other fluorometric procedures, the proposed method is the simplest one, rapid and easy to perform, demanding the least time for oxidation and not using hazardous chemicals (KMnO4 instead of KCN). Good recovery, low relative standard deviation and low total error allow the proposed procedure to be included into the group of excellent methods.
Die fluorometrische Methode zur Vitamin B6-Bestimmung in Soja
Zusammenfassung Die einfache fluorometrische Methode zur Bestimmung von zugegebenem Pyridoxin in angereicherten Lebensmitteln basiert auf der Oxidation des Pyridoxins mit Kaliumpermanganat zur 4-Pyridoxinsäure und wurde für die Bestimmung des gesamten Vitamin B6 in Soja modifiziert. Im Vergleich mit anderen fluorometrischen Methoden ist die vorgeschlagene, einfach, schnell und leicht durchzuführen. Diese Methode braucht nur wenig Zeit für die Oxidation und verwendet ungiftige Chemikalien (KMnO4 statt KCN). Die gute Wiederfindung, die geringe relative Standardabweichung und der geringe Gesamtfehler reiht das vorgeschlagene Verfahren in die Gruppe der ausgezeichneten Methoden ein.相似文献
995.
A method for calculation the impulse response of a depletion layer of a semiconductor device based on Ramo's theorem is described. Using this method the impulse response of a reach-through avalanche photodiode is derived. 相似文献
996.
Anisotropic mesh adaptation for finite volume and finite element methods on triangular meshes 总被引:1,自引:0,他引:1
Vít Dolejší 《Computing and Visualization in Science》1998,1(3):165-178
The present paper deals with an anisotropic mesh adaptation (AMA) of triangulation which can be employed for the numerical
solution various problems of physics. AMA tries to construct an optimal triangulation of the domain of computation in the
sense that an “error” of the solution of the problem considered is uniformly distributed over the whole triangulation. First,
we describe the main idea of AMA. We define an optimal triangle and an optimal triangulation. Then we describe the process
of optimization of the triangulation and the complete multilevel computational process. We apply AMA to a problem of CFD,
namely to inviscid compressible flow. The computational results for a channel flow are presented.
Received: 11 December 1997 / Accepted: 16 February 1998 相似文献
997.
998.
The coating of pseudoplastic liquids onto a vertical surface continuously withdrawn from the liquid bath is considered. The problem is treated in a two-dimensional nonlinear approach incorporating the inertial effects. The model gives a relationship between the dimensionless film thickness, T, and the Capillary number, Ca, as a function of the fluid physical properties and the parameteres of the power-law model. The comparison with the experimental data is satisfactory. 相似文献
999.
The membrane-interacting abilities of three sequences representing the putative fusogenic subdomain of the Ebola virus transmembrane protein have been investigated. In the presence of calcium, the sequence EBO(GE) (GAAIGLAWIPYFGPAAE) efficiently fused unilamellar vesicles composed of phosphatidylcholine, phosphatidylethanolamine, cholesterol, and phosphatidylinositol (molar ratio, 2:1:1:0.5), a mixture that roughly resembles the lipid composition of the hepatocyte plasma membrane. Analysis of the lipid dependence of the process demonstrated that the fusion activity of EBO(GE) was promoted by phosphatidylinositol but not by other acidic phospholipids. In comparison, EBO(EA) (EGAAIGLAWIPYFGPAA) and EBO(EE) (EGAAIGLAWIPYFGPAAE) sequences, which are similar to EBO(GE) except that they bear the negatively charged glutamate residue at the N terminus and at both the N and C termini, respectively, induced fusion to a lesser extent. As revealed by binding experiments, the glutamate residue at the N terminus severely impaired peptide-vesicle interaction. In addition, the fusion-competent EBO(GE) sequence did not associate significantly with vesicles lacking phosphatidylinositol. Tryptophan fluorescence quenching by vesicles containing brominated phospholipids indicated that the EBO(GE) peptide penetrated to the acyl chain level only when the membranes contained phosphatidylinositol. We conclude that binding and further penetration of the Ebola virus putative fusion peptide into membranes might be governed by the nature of the N-terminal residue and by the presence of phosphatidylinositol in the target membrane. Moreover, since insertion of such a peptide leads to membrane destabilization and fusion, the present data would be compatible with the involvement of this sequence in Ebola virus fusion. 相似文献
1000.
T Mester HJ Swarts S Romero i Sole JA de Bont JA Field 《Canadian Metallurgical Quarterly》1997,63(5):1987-1994
Aryl metabolites are known to have an important role in the ligninolytic system of white rot fungi. The addition of known precursors and aromatic acids representing lignin degradation products stimulated the production of aryl metabolites (veratryl alcohol, veratraldehyde, p-anisaldehyde, and 3-chloro-p-anisaldehyde) in the white rot fungus Bjerkandera sp. strain BOS55. The presence of manganese (Mn) is known to inhibit the biosynthesis of veratryl alcohol (T. Mester, E. de Jong, and J.A. Field, Appl. Environ. Microbiol. 61:1881-1887, 1995). A new finding of this study was that the production of the other aryl metabolites, p-anisaldehyde and 3-chloro-p-anisaldehyde, was also inhibited by Mn. We attempted to bypass the Mn-inhibited step in the biosynthesis of aryl metabolites by the addition of known and suspected precursors. Most of these compounds were not able to bypass the inhibiting effect of Mn. Only the fully methylated precursors (veratrate, p-anisate, and 3-chloro-p-anisate) provided similar concentrations of aryl metabolites in the presence and absence of Mn, indicating that Mn does not influence the reduction of the benzylic acid group. The addition of deuterated benzoate and 4-hydroxybenzoate resulted in the formation of deuterated aryl metabolites, indicating that these aromatic acids entered into the biosynthetic pathway and were common intermediates to all aryl metabolites. Only deuterated chlorinated anisyl metabolites were produced when the cultures were supplemented with deuterated 3-chloro-4-hydroxybenzoate. This observation combined with the fact that 3-chloro-4-hydroxybenzoate is a natural product of Bjerkandera spp. (H. J. Swarts, F. J. M. Verhagen, J. A. Field, and J. B. P. A. Wijnberg, Phytochemistry 42:1699-1701, 1996) suggest that it is a possible intermediate in chlorinated anisyl metabolite biosynthesis. 相似文献