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排序方式: 共有473条查询结果,搜索用时 15 毫秒
71.
The characteristics of four (4) lithium drifted silicon surface barrier detectors have been studied. Detector noise and leakage current were measured at the beginning and end of a sixteen (16) mounth interval. The thickness of the intrinsic region, at the beginning and end of a fourteen (14) month interval, was determined by use of proton beams from the University of Southern California Linac and the University of Colorado cyclotron. Detector noise measurements were made using both a standard pulser technique and the photopeak from Ba133 . The noise and leakage were measured at -54°C, +20°C aud +60°C. The detector leakage was measured as a function of bias at +20°C. The detector thickness measurements were also performed at +20°C 相似文献
72.
73.
W. D. Hubbard A. J. Sheppard D. R. Newkirk A. R. Prosser T. Osgood 《Journal of the American Oil Chemists' Society》1977,54(2):81-83
Seven methods were used to compare the efficiency of total lipid extraction from 13 samples of eight different food products. The methyl esters of fatty acids and the butyrate esters of sterols were prepared and analyzed by gas liquid chromatography. On the basis of total lipid recovered and amounts of fatty acids and sterols present, a chloroform: methanol procedure was selected as the most effective method. 相似文献
74.
75.
Heterotopic ossification (HO) after femoral intramedullary rodding is a significant complication of the procedure. One hundred eighteen cases of femoral roddings performed on 113 patients were available for review. The data were computerized and evaluated using univariate analysis and multivariate regression analysis. A statistically significant increase of HO was found with male gender, increased delay to surgery, and in patients requiring prolonged intubation because of their multiple injuries. HO was classified using a modified version of the method of Brumback et al. (grades 0-IV). A strong correlation of HO with brain injury documented by computed tomography scan was also found to be statistically significant for the more severe grades of HO. This group of patients had not previously been identified as being at high risk for HO. 相似文献
76.
Bruno Barazani Marta Piercey Allan Paulson Stephan Warnat Ted Hubbard Andrew J. MacIntosh 《Journal of the Institute of Brewing》2019,125(1):53-59
This study investigated the rehydration of active dried yeast and the impact of temperature and wort density on the strength and stiffness of individual cells using a microelectromechanical system. Dried yeast was rehydrated using a variety of methods, including direct pitching into wort (13.6°P) at 12, 22 and 30°C, as well as propagation using YEPD media (4.2°P). Cell viability was found to broadly correlate with measurement of cell strength and stiffness. Both wort density and temperature affected viability and physical characteristics of the cells after 1 h of rehydration. Yeast cells rehydrated at low temperature and high wort density burst at a lower force (0.26 ± 0.02 μN) than cells rehydrated using high temperature and low density media (0.50 ± 0.10 μN). Cells rehydrated at higher temperatures or using low density media showed no significant difference in strength and stiffness when compared with high viability, actively fermenting yeast. Changes in yeast physiology, owing to stress responses, may contribute to the observed differences in mechanical properties. These findings have application in brewery design, as pumping, centrifugation, storage and associated shear impart mechanical stress upon yeast cells. © 2018 The Institute of Brewing & Distilling 相似文献
77.
Buchner S Kinnear M Crouch IJ Taylor J Minnaar A 《Journal of the science of food and agriculture》2011,91(15):2814-2820
BACKGROUND: Pears are exported in large quantities from South Africa, resulting in large revenues. Minimisation of quality losses once the fruit has reached the export destination is as important as following strict export and distribution protocols. Kafirin can form edible films. In this study an edible coating made from 20 g kg?1 kafirin coating solution was applied as a postharvest treatment to retard quality deterioration of ‘Packham's Triumph’ pears during storage at the typical ripening temperature (20 °C). Changes in physicochemical and sensory quality were monitored over a period of 24 days. RESULTS: The kafirin coating was unable to retard the onset of ripening but decreased the respiration rate and retarded the progression of senescence. However, moisture loss was exacerbated in the kafirin‐coated fruit during ripening at 20 °C, especially towards the end of the shelf‐life. CONCLUSION: The kafirin coating extended the eat‐ripe quality of the pears by 1–2 weeks. However, the appearance of the fruit was unacceptable after 14 days of storage in terms of wrinkled skin. Further work is needed to improve the water barrier properties of the kafirin coating by incorporating a wax or triglyceride into the coating formulation or more simply by applying a kafirin coating to waxed fruit. Copyright © 2011 Society of Chemical Industry 相似文献
78.
Redjala Sonya Ferhoum Rabah Aït Hocine Nourredine Azem Said 《Journal of Failure Analysis and Prevention》2019,19(2):536-542
Journal of Failure Analysis and Prevention - The aim of this paper is to characterize the thermal aging effect near the glass transition temperature of polycarbonate (PC) at different hold time.... 相似文献
79.
Thin sections cut from cast concrete cylinders have been examined in transmitted light to investigate the significance of coarse aggregate type in “primary” microfracturing. Concretes manufactured with crushed-rock aggregates and gravel aggregates were studied and, in every case, the dominant fracture type was a parting of the aggregate-matrix bond. Bond cracking was least severe with the marble aggregate where epitaxial calcite over-growth was indicated. The ability of bond cracks to maintain continuity by bridging surface irregularities, via mortar cracks, reduced the inhibiting influence of rough-surfaced aggregate on bond-crack development. 相似文献
80.
L Fenster K Waller J Chen AE Hubbard GC Windham E Elkin S Swan 《Canadian Metallurgical Quarterly》1999,149(2):127-134
Invasive squamous carcinoma of the uterine cervix (CC) arises from sequential progression of low-grade (L) and high-grade (H) squamous intraepithelial lesions (SILs). In clinical observations, these lesions are frequently found as synchronous multiple foci. The nature and evolutionary mechanism of these lesions are largely unknown. We have performed allelotyping of three 3p markers (at 3p14, 3p22-24, and 3p25) on 22 LSILs and 15 HSILs microdissected from patients with multiple (n = 21) or uniform (n = 6) cervical lesions. The results were analyzed together with our previous allelotyping of 57 deeply invasive CCs. Loss of heterozygosity at one of the three markers was observed in 23%, 27%, and 31 % of LSILs, HSILs, and CCs, respectively. Frequent and early allelic loss was noted (in 30% of LSILs and 50% of HSILs) at 3p14, which may harbor tumor suppressor genes involved in early stages of cervical carcinogenesis. A high frequency of microsatellite alteration (MA) was found in LSIL (41%) and HSIL (67%) but not in CC (5.3%). In particular, MA was more frequently found in low-grade lesions in association with invasive cancers (75%, 6/8) than in those associated with SILs (29%, 4/14) (P < 0.05). Together with the finding of a monoclonal origin of premalignant and malignant cervical lesions, the present results allow us to propose a model of local field effect of genomic instability that progressively affects the clonal evolution of SIL of uterine cervix. 相似文献