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排序方式: 共有186条查询结果,搜索用时 46 毫秒
11.
12.
Yizhang Zhou Steven Lee Vincent G. McDonell Scott Samuelson Enrique J. Lavernia Robert L. Kozarek 《Metallurgical and Materials Transactions B》1998,29(4):793-806
Linear spray atomization and deposition is an attractive technique to produce near-net-shape deposits, such as aluminum sheet
and strip. In the present study, phase Doppler interferometry (PDI) was used in a backscatter mode to characterize, in situ, the droplet size and velocity distributions during linear spray atomization and deposition of a 3003 aluminum alloy. The
PDI measurements were obtained along axes corresponding to the direction parallel to the nozzle slit and to the direction
perpendicular to the slit. The PDI results delineate the temporal and spatial distribution of the droplet size and velocity
during the metal spray. Both point and “line” measurements were obtained and are reported. The line measurements resulted
from the integration of measurement made along a line scan obtained in real time (i.e., not ensemble averaged). Postrun analysis of the droplet size distribution using laser diffraction and sieving techniques
is also reported. The PDI point measurements revealed that droplet size and velocity distribution were relatively invariant
with time. The line measurements of droplet velocity showed that the droplet axial velocity exhibits a bimodal behavior, which
becomes more apparent with increasing atomizing gas pressure, a result of droplet recirculation inside the spray chamber.
In addition, the peak in the droplet axial velocity distribution increased as atomizing gas pressure increased. The line characterization
also showed that the droplet size distribution became more homogeneous with increasing gas pressure, and that the distribution
characteristic diameters of droplets decreased consistently with increasing gas pressure. Postrun characterization of the
droplet size distribution of the entire metal spray using diffraction and sieving methods indicated that the mass (volume)
median diameter D
50 and the Sauter mean diameter (SMD) D
32 decreased with increasing gas pressure in a manner consistent with PDI results. 相似文献
13.
Motor nerve terminals on abdominal body-wall muscles 6A and 7A in larval flesh flies were investigated to establish their general structural features with confocal microscopy, transmission electron microscopy, and freeze-fracture procedures. As in Drosophila and other dipterans, two motor axons supply these muscles, and two morphologically different terminals were discerned with confocal microscopy: thin terminals with relatively small varicosities (Type Is), and thicker terminals with larger varicosities (Type Ib). In serial electron micrographs, Type Ib terminals were distinguished from Type Is terminals by their larger cross-sectional area, more extensive subsynaptic reticulum, more mitochondrial profiles, and more clear synaptic vesicles. Type Ib terminals possessed larger synapses and more synaptic contact area per unit terminal length. Although presynaptic dense bars of active zones were similar in mean length for the two terminal types, there were almost twice as many dense bars per synapse for Type Ib terminals. Freeze-fractures through the presynaptic membrane showed particle-free areas indicative of synapses on the P-face, within which were localized aggregations of large intramembranous particles indicative of active zones. These particles were similar in number to those found at active zones of several other arthropod neuromuscular junctions. In general, synaptic structural parameters strongly paralleled those of the anatomically homologous muscles in Drosophila melanogaster. In live preparations, simultaneous focal recording from identified varicosities and intracellular recording indicated that the two terminals produced excitatory junction potentials of similar amplitude in a physiological solution similar to that used for Drosophila. 相似文献
14.
M Samuelson LF Draganich X Zhou P Krumins B Reider 《Canadian Metallurgical Quarterly》1996,24(4):492-497
We tested the effect of intraarticular reconstructions of the anterior cruciate ligament alone and in combination with extraarticular reconstructions in 10 cadaveric knees. These knees had anterior cruciate ligament deficiency alone or in combination with anterolateral capsuloligamentous deficiencies. In the knees with combined injury, intraarticular reconstruction returned anterior stability to levels not significantly different from levels found for the knees deficient in the anterior cruciate ligament alone and treated with this procedure. After intraarticular reconstruction, rotational stability of the knee with combined injuries failed to return to the levels seen in the knee with isolated anterior cruciate ligament deficiencies that underwent the same treatment. When a tenodesis with either 0 N or 22 N of tension was added to the intraarticular reconstruction in the knee with combined injuries, we found that excessive internal rotation significantly decreased at all angles of flexion, except at full extension with 0 N of tension. In addition, the extraarticular reconstruction with 22 N of tension in the tenodesis overconstrained the knee in internal rotation between 30 degrees and 90 degrees of knee flexion. The tenodesis with 0 N of tension overconstrained the knee at only 60 degrees and 90 degrees of flexion. These results suggest extraarticular reconstruction as an adjunct to the intraarticular operation for the knee with anterior cruciate ligament and anterolateral structural injuries. The results also suggest that the surgeon can affect anterior and rotational laxity by adjusting the tension in the tenodesis. 相似文献
15.
16.
Nuclear structure data available through January 1976 are compiled, and adopted level properties are given. The bulk of the data is presented pictorially for easy comparison. Experimental details, references, and additional comments, where required, are given in the text. All drawings, tables, and comments are reproduced from the computerized Evaluated Nuclear Structure Data File (ENSDF). Any additions or corrections desired by the users should be addressed to the compilers for maintenance and updating of the computer file. 相似文献
17.
Shorubalko I. Xu H.Q. Maximov I. Nilsson D. Omling R. Samuelson L. Seifert W. 《Electron Device Letters, IEEE》2002,23(7):377-379
In this letter, a novel frequency-multiplication device based on a three-terminal ballistic junction is proposed and demonstrated. A 100 nm-size, three-terminal ballistic junction and a one-dimensional (1D), lateral-field-effect transistor with trench gate-channel insulation are fabricated from high-electron-mobility GaInAs/InP quantum-well material as a single device. The devices show frequency doubling and gain at room temperature. The performance of these devices up to room temperature originates from the nature of the device functionality and the fact that the three-terminal device extensions are maintained below the carrier mean-free path. Furthermore, it is expected that the device performance can be extended up to THz-range 相似文献
18.
19.
Samuelson Charles D.; Messick David M.; Rutte Christel; Wilke Henk 《Canadian Metallurgical Quarterly》1984,47(1):94
Administered a resource management task to 86 US and 97 Dutch undergraduates. Ss were divided into groups of 6 and instructed to harvest points from a regenerating resource pool. Their objective was to maximize individual harvests while maintaining the resource pool. The factorial design crossed 3 levels of resource use (overuse, underuse, and optimal use) with 2 levels of variance of others' purported harvests (low and high). Both variables were manipulated through false feedback to Ss regarding the pool size and the other Ss' harvests. The primary dependent measures were Ss' individual harvests and whether Ss voted for or against elimination of free access to the resource in favor of electing a leader who would make harvest decisions for the group. Results indicate that harvest size increased over time only in the under- and optimal-use conditions. As predicted, overuse Ss voted to give up free access to the resource and to elect a leader more frequently than Ss in the other conditions. Differences between American and Dutch Ss were found only for the variance manipulation. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
20.
PN Samuelson RG Merin DR Taves RB Freeman JF Calimlim T Kumazawa 《Canadian Metallurgical Quarterly》1976,23(5):465-479
Seven obese and five normal weight patients were studied before, during and after one hour of methoxyflurane-nitrous oxide anaesthesia during peripheral surgical operations and compared with eight patients of normal weight anaesthetized with nitrous oxide-meperidine and d-tubocurare. Estimates were made of renal function, including serum and urinary electrolytes, osmolarity, uric acid, urea and creatinine. Renal clearances for the latter three substances were also calculated. Serum and urinary inorganic and organic fluoride concentrations were measured, as were renal clearances. This low dose methoxyflurane anaesthesia resulted only in a decrease in uric acid clearance among all the measures, when compared to the meperidine-nitrous oxide controls. The clearance of uric acid remained depressed for longer in the obese patients, but otherwise they did not differ from the normal weight patients. It is possible but not proven that depressed uric acid clearance may be related to the organic fluoride metabolite and an early indicator of methoxyflurane renal toxicity. The previously documented biotransformation of methoxyflurane was seen in this study. A double peak in serum inorganic fluoride was shown in all patients but one. Rather large differences in peak levels of serum inorganic fluoride occurred. The only significant difference between the obese and normal weight patients as far as fluoride metabolism was concerned was a greater variability in the serum inorganic fluoride levels in the obese patients. It would appear that the obese patient metabolizes methoxyflurane in a quantitatively if not qualitatively different fashion than the normal weight patient, perhaps because of fatty infiltration of the liver. Caution is advised in the use of methoxyflurane for more than 90 minutes of low concentration administration in view of the unpredictability of the biotransformation. 相似文献