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61.
62.
Waviness removal in grinding of wire-sawn silicon wafers: 3D finite element analysis with designed experiments 总被引:1,自引:1,他引:1
Xuekun Sun Z. J. Pei X. J. Xin Mandy Fouts 《International Journal of Machine Tools and Manufacture》2004,44(1):11-19
Silicon wafers are used to fabricate more than 90% of integrated circuits. Surface grinding has been used to flatten wire-sawn silicon wafers. A major issue in grinding of wire-sawn wafers is that conventional grinding cannot effectively remove the waviness induced by wire-sawing process. Soft-pad grinding is a promising method to effectively remove waviness. This paper presents the results of three-dimensional (3D) finite element analysis of soft-pad grinding of wire-sawn silicon wafers. In this investigation, a four-factor two-level full factorial design is employed to reveal main effects as well as interaction effects of four factors (Young’s modulus, Poisson’s ratio, and thickness of the soft pad, and waviness wavelength of the wafer) on the effectiveness of waviness reduction. Implications of this study to manufacturing are also discussed. 相似文献
63.
64.
Bozena B. Mulsow Mandy Jacob Thomas Henle 《European Food Research and Technology》2009,228(4):643-649
It could be shown for technologically relevant whey protein powders that denaturation of β-lactoglobulin (β-Lg) is affected
significantly by the extent of covalent modification of lysine residues by lactose. The amount of acid soluble β-Lg as measured
via RP-HPLC with UV detection after heating for 10 min at 80 °C increased from 40% (4.6% lysine modification) to 82% (22.4%
lysine modification). An increase in glycation leads to a slower denaturation-induced oligomerisation, as shown by SDS-PAGE.
Concomitant with an increase in lysine modification, the denaturation temperature increased from 79.5 to 84 °C, as measured
by differential scanning calorimetry (DSC). Covalent attachment of lactose to whey proteins during preparation or storage
significantly improves the heat stability of whey proteins, which may be of particular importance for the technological use
of whey proteins varying in the degree of lysine modification. 相似文献
65.
Roberto Köferstein Lothar Jäger Mandy Zenkner Stefan G. Ebbinghaus 《Journal of the European Ceramic Society》2009,29(11):2317-2324
Preparation of a very fine BaSnO3 powder by calcination of a barium tin 1,2-ethanediolato complex precursor and its sintering behaviour are described herein. A rate controlled calcination process to 820 °C leads to a nm-sized BaSnO3 powder with a specific surface area of S = 15.1 m2/g (dav. = 55 nm). The powder has a slightly larger cell parameter of a = 412.22(7) pm compared to the single crystal value, which decreases with increasing calcination temperature and reaches the reference value above 1000 °C. The sintering behaviour is compared between fine and coarse-grained BaSnO3 powders. Corresponding powder compacts of the nano-sized BaSnO3 achieve a relative density of 90% after sintering at 1600 °C for 1 h and at 1500 °C and a soaking time of 30 h, whereas coarse-grained powder compacts reach only 80% of the relative density at 1650 °C (10 h). Furthermore, the shrinkage mechanisms of fine and coarse-grained powder compacts have been investigated and are discussed. 相似文献
66.
67.
Slightly weathered Exxon Valdez oil persists in Gulf of Alaska beach sediments after 16 years 总被引:5,自引:0,他引:5
Short JW Irvine GV Mann DH Maselko JM Pella JJ Lindeberg MR Payne JR Driskell WB Rice SD 《Environmental science & technology》2007,41(4):1245-1250
Oil stranded by the 1989 Exxon Valdez spill has persisted in subsurface sediments of exposed shores for 16 years. With annualized loss rates declining from approximately 68% yr(-1) prior to 1992 to approximately 4% yr(-1) after 2001, weathering processes are retarded in both sediments and residual emulsified oil ("oil mousse"), and retention of toxic polycyclic aromatic hydrocarbons is prolonged. The n-alkanes, typically very readily oxidized by microbes, instead remain abundant in many stranded emulsified oil samplesfrom the Gulf of Alaska. They are less abundant in Prince William Sound samples, where stranded oil was less viscous. Our results indicate that, at some locations, remaining subsurface oil may persist for decades with little change. 相似文献
68.
Callaway TR Carroll JA Arthington JD Edrington TS Rossman ML Carr MA Krueger NA Ricke SC Crandall P Nisbet DJ 《Journal of food protection》2011,74(11):1917-1921
Foodborne pathogenic bacteria such as Escherichia coli O157:H7 are threats to the safety of beef. Citrus peel and dried orange pulp are by-products from citrus juice production that have natural antimicrobial effects and are often incorporated into least-cost ration formulations for beef and dairy cattle. This study was designed to determine if orange peel and pulp affected E. coli O157:H7 populations in vivo. Sheep (n = 24) were fed a cracked corn grain-based diet that was supplemented with a 50-50 mixture of dried orange pellet and fresh orange peel to achieve a final concentration (dry matter basis, wt/wt) of 0, 5, or 10% pelleted orange peel (OP) for 10 days. Sheep were artificially inoculated with 10(10) CFU of E. coli O157:H7 by oral dosing. Fecal shedding of E. coli O157:H7 was measured daily for 5 days after inoculation, after which all animals were humanely euthanized. At 96 h postinoculation, E. coli O157:H7 shedding was reduced (P < 0.05) in sheep fed 10% OP. Populations of inoculated E. coli O157:H7 were reduced by OP treatment throughout the gastrointestinal tract; however, this reduction reached significant levels in the rumen (P < 0.05) of sheep fed 10% OP diets. Cecal and rectal populations of E. coli O157:H7 were reduced (P < 0.05) by inclusion of both 5 and 10% OP diets. Our results demonstrate that orange peel products can be used as a preharvest intervention strategy as part of an integrated pathogen reduction scheme. 相似文献
69.
70.
Robert I. Scott Susan Sladen Mandy Maidment Tahira Rashid Christos Pratsis David Perry 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1988,41(2):145-154
The physiology of Streptomyces clavuligerus has been studied by investigating oxygen uptake and β-lactam (clavulanic acid) production by free and alginate entrapped cells. The specific oxygen uptake rate of cells entrapped in strontium or calcium alginate was only about 35% of the rate in free cells. This reduction in oxygen uptake was due to reduced internal diffusion of oxygen; in addition calcium, barium and strontium ions could also cause oxygen uptake in free cells to be inhibited. Measurements of the deformation of individual gel beads showed that maximum hardness was reached after 15 min exposure to 0.14 mol dm?3 Ca2+. Exposure of cells to Ca2+ for this time caused a 15% reduction in the rate of oxygen uptake. Levels of clavulanic acid produced by free cells were higher than those produced by immobilized cells; production was dependent on the degree of aeration of the cells. 相似文献