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991.
The limiting level of sheet glass hardening is presented based on three classification strength criteria and is equal to about 500 MPa. 相似文献
992.
G Franzosi E Battistel I Gagliardi W Van der Goes 《Canadian Metallurgical Quarterly》1995,43(3):508-513
A screening of microorganisms producing glutaryl-7ADCA acylase, an enzyme able to hydrolyse glutaric acid selectively from glutaryl-3-deacetoxy-7-aminocephalosporanic acid (glutaryl-7ADCA), has been carried out in soil samples. Five microorganisms expressing acylase activity were isolated and classified as Bacillus cereus, Achromobacter xylosooxidans, Bacillus sp., Pseudomonas sp. and Pseudomonas paucimobilis. The screening was carried out by preparing enrichment cultures containing glutaryl-7-ADCA or cephalosporin C as the selective carbon source. Four model compounds (adipoyl-, glutamyl- and glutaryl-p-nitroanilide and glutarylcoumarin), mimicking the glutaryl-7ADCA beta-lactam moiety, were synthesized as substrates suitable for the rapid screening of the microorganisms (2500) isolated from the enrichment cultures. A total of 300 strains were active on the model substrates and only 5 displayed acylase activity on glutaryl-7ADCA. The fermentation parameters, such as pH and inducer concentration, for the optimal acylase expression and acylase specificity towards the model substrates were different for each strain. 相似文献
993.
The advantages and disadvantages of using a high-pressure pneumatic pump at porcelain and insulator works are discussed. The testing results of a prototype pump are described. 相似文献
994.
The properties of the relaxation (wave) model of longitudinal dispersion are considered. The diffusion and relaxation models of longitudinal dispersion are compared. It is shown that, depending on its coefficients, the relaxation model can be assigned to two main classes and one intermediate class provided the boundary conditions for the model equations are correctly formulated. New equations are obtained, whose solutions are asymptotically close to the solutions of the diffusion model. 相似文献
995.
996.
G.P. Berman G.D. DoolenG.V. López V.I. Tsifrinovich 《Computer Physics Communications》2002,146(3):324-330
We demonstrate a strategy for implementation a quantum full adder in a spin chain quantum computer. As an example, we simulate a quantum full adder in a chain containing 201 spins. Our simulations also demonstrate how one can minimize errors generated by non-resonant effects. 相似文献
997.
998.
This article examines the advantages and disadvantages of using guillotine shears with an inclined top blade for the cross-cutting of flat-rolled products on modern plate mills. It is shown that it is necessary to use shears of an improved design. After shears with a “rolling cut,” designed by the All-Russia Scientific Research, Planning, and Design Institute of Metallurgical Machinery (VNIImetmash), were installed in the line of the 2800 plate mill at the Ural Steel combine, the institute conducted studies to optimize the parameters of the cutting operation and developed recommendations for the shears operators on how to adjust the shears to obtain a quality cut edge on the plates. 相似文献
999.
Polymer clay nanocomposites (PCN) exhibit improved mechanical properties due to nanolevel dispersion of clay in the polymer
matrix. They also exhibit good tribological performance under dry sliding conditions. Abrasive wear behaviour of these materials
would be different from dry sliding behaviour as the mechanisms of the both are entirely different. Hence the abrasive wear
behaviour of these materials needs to be investigated. The abrasive wear characteristics of polyamide 6 nanocomposites, with
1, 3 and 5% (wt.) clay prepared by melt intercalation technique, under two-body abrasive wear conditions have been reported.
Abrasive wear tests were conducted using a pin-on-disc tribometer containing an abrasive counterface. All the polyamide nanocomposites
investigated exhibited a low abrasive wear resistance compared with pristine Nylon. The wear performance of the nanocomposites
was correlated with the mechanical properties. Dominant ploughing and cutting wear were observed in polymer clay nanocomposites.
The amount of clay present alters the wear mechanism. 相似文献
1000.