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排序方式: 共有819条查询结果,搜索用时 15 毫秒
61.
J H Harrison D D Hancock N St Pierre H R Conrad W R Harvey 《Journal of dairy science》1986,69(5):1421-1425
Selenium injections and oral vitamin E supplementation prepartum were related to: postpartum uterine involution (decrease in uterine size per unit time) and days to minimum uterine size in a 2 X 2 factorial design. Complete data were analyzed from 64 cows. Groups were selenium plus vitamin E, vitamin E, selenium, and control. Factors significantly affecting uterine size between 14 and 50 d postpartum were cow weight, days postpartum-linear, days postpartum-quadratic, day X metritis, and day X metritis X selenium treatment. Days to minimum uterine size were significantly less in cows with metritis and selenium treated when compared with cows with metritis and not selenium treated (32.9 vs. 35.8). 相似文献
62.
The influence of a continuous dc electric field applied orthogonal to the tensile direction on the flow stress, grain growth,
and cavitation during superplastic deformation (SPD) of ultrafine-grained 3Y-TZP at 1,450–1,600 °C was determined. The field
gave a significant reduction in the level of the stress-strain curve, and reduced grain growth and cavitation. The decrease
in flow stress by the field was attributed mainly to the retardation of grain growth. The decrease in cavitation correlated
with the retardation of grain growth and was attributed largely to the reduction in flow stress by the field. 相似文献
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65.
Makarand R. Gogate Byung Gwon Lee Sunggyu Lee Conrad J. Kulik 《Petroleum Science and Technology》1990,8(6):637-671
The kinetics of the liquid phase catalytic dehydration of methanol to dimethyl ether were investigated. The experiments were carried out under low concentrations of feed in a 1-L stirred autoclave, according to a statistical experimental design. The inert liquid phase used for this investigation was a 78:22 blend of paraffinic and naphthenic mineral oils. A complete thermodynamic analysis was carried out in order to determine the liquid phase concentrations of the dissolved species. A global kinetic model was developed for the rate of dimethyl ether synthesis in terms of the liquid phase concentration of methanol. The activation energy of the reaction was found to be 18,830 cal/gmol. Based on a step-wise linear regression analysis of the kinetic data, the order of the reaction which gave the best fit was 0.28 with respect to methanol. Effects of the solid to liquid and the gas to liquid mass transfer resistances on the kinetic rate have also been investigated. 相似文献
66.
The authors examined whether 2 computational models of reading, the dual-route cascaded model (M. Coltheart, K. Rastle, C. Perry, R. Langdon, and J. C. Ziegler, 2001) and the connectionist 2-layer model (M. Zorzi, G. Houghton, and B. Butterworth, 1998), were able to predict the pattern that the length effect found in reading aloud is larger in German than in English (J. C. Ziegler, C. Perry, A. M. Jacobs, and M. Braun, 2001). The results showed that the dual-route cascaded model, which uses a serial mechanism for assembling phonology, successfully predicted this cross-language difference. In contrast, the connectionist model of Zorzi et al. (1998) predicted the opposite: a larger length effect in English than in German. Both the success of one model and the failure of the other highlight fundamental differences between 2 major classes of computational models. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
GE O'Keefe RV Maier P Diehr D Grossman GJ Jurkovich D Conrad 《Canadian Metallurgical Quarterly》1997,132(8):920-4; discussion 925
OBJECTIVES: To estimate the expected costs for acute trauma care, to quantify the costs associated with the development of complications in injury victims, and to determine the deficit incurred by patients in whom complications develop. DESIGN: A retrospective, cohort design. SETTING: A referral trauma center. PATIENTS: A total of 12,088 patients admitted to a single regional trauma center during a period of 5 years. INTERVENTIONS: This is an observational study, and no interventions specific to this study are included in the design. MAIN OUTCOME MEASURES: (1) The expected costs for injury victims based on readily available clinical data. (2) The costs associated with the most important complications of trauma. (3) The effect of complications on inadequate reimbursement for trauma care. RESULTS: The expected costs were estimated using a linear model incorporating demographic variables and measures of injury severity. The expected costs averaged $14,567, and the observed costs averaged $15,032. Six complications were important predictors of cost. These included adult respiratory distress syndrome, acute kidney failure, sepsis, pneumonia, decubitus ulceration, and wound infections. For 1201 individuals with these complications, the predicted costs averaged $23,266 and the observed costs averaged $47,457. The mean excess costs for a single complication ranged from $6669 to $18,052. Multiple complications led to greater increases in excess cost, averaging $110,007 for the 62 patients with 3 or more complications. Costs exceeded reimbursement to a much greater degree in those in whom any of the 6 complications developed. CONCLUSION: Expected hospital costs can be estimated using admission clinical data. Each of 6 complications was associated with enormous increases in costs, indicating their importance as a cause of avoidable expenditures in injury victims and identifying situations in which reimbursement may not be adequate. 相似文献
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69.
Michael P.C. Conrad 《Polymer》2007,48(18):5233-5240
Aromatic hybrid fluorosilicones, such as perfluorocyclobutane aromatic polyethers, have higher thermal stability than typical polysiloxanes. While these polyethers decompose by homolytic cleavage of the oxygen-perfluorocyclobutane bond, the enhanced thermal stability of the polyethers may, in part, arise from this oxygen through the anomeric effect. To determine the effect of the ether oxygen on thermal stability, two perfluorocyclobutane aromatic units, one with and one without the oxygen, were modeled. To confirm the results experimentally, a series of hybrid fluorosilicones based on the latter were synthesized by thermocyclodimerization of 1-bromo-4-(trifluorovinyl)benzene, metal-halogen exchange, and condensation with one of 1,3-dichlorotetramethyldisiloxane; 1,7-dichlorooctamethyltetrasiloxane; or chlorine-terminated poly(dimethylsiloxane). The degradation temperature (T1%) was lower (∼240 °C) than the comparable polyethers (∼430 °C). These results demonstrate the importance of the ether oxygen to the stability of perfluorocyclobutane aromatic polyethers through a number of effects including the anomeric effect and enhancing the strength of the silicon-aromatic bond. 相似文献
70.
The phase size distributions (PSDs) of the Sn, Pb, and the combined Pb and Sn phases, and the shape factor δ were determined
for as-reflowed 60Sn40Pb solder joints and following their annealing at 50°C to 150°C. The PSDs in all cases had a positive
skew which was approximated by a log-normal function. The PSDs were time invariant and were in accord with the Bitti and Nunzio
model for phase coarsening. The shape factor, δ, decreased with the mean of the combined Pb and Sn phase size, and with temperature.
Whether or not δ affects the PSDs is not clear. 相似文献