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排序方式: 共有1442条查询结果,搜索用时 31 毫秒
121.
Anand A. Kulkarni Herbert Herman Jon Almer Ulrich Lienert Dean Haeffner Jan Ilavsky Stacy Fang Paul Lawton 《Journal of the American Ceramic Society》2004,87(2):268-274
Demands for designing prime reliant, energy-efficient, and high-performance thermal barrier coatings (TBCs) in gas turbines have led to a growing interest toward comprehensive microstructural characterization. Here we investigate the novel use of high-energy X-rays for small-angle X-ray scattering (SAXS), together with wide-angle scattering and radiography, for the depth-resolved characterization of TBCs grown by electron beam physical vapor deposition (EB-PVD). The coating microstructure is found to consist of columns perpendicular to the substrate, extending through the thickness, with a [001] growth texture and significant intercolumnar porosity. In addition, overshadowing effects during deposition together with gas entrapment give rise to nanoscale intracolumnar porosity consisting of featherlike and globular pores. Radiography showed an increase in the total porosity, from 15% near the substrate to 25% near the coating surface, which is ascribed to an increase in the intercolumnar spacing at the top of the coating. By contrast, the small-angle scattering studies, which are sensitive to fine features, showed the pore internal surface area to be greatest near the substrate. 相似文献
122.
F Sandouk S Haffar MM Zada DY Graham BS Anand 《Canadian Metallurgical Quarterly》1997,92(12):2264-2267
BACKGROUND: Infestation with Ascaris lumbricoides is seen worldwide. Recently, there has been much interest in the pancreatic-biliary complications of Ascaris infection. In this study, we present our experience of 300 patients seen in a tertiary referral center. MATERIALS AND METHODS: Case charts of patients seen in the Department of Gastroenterology, University of Damascus, Syria, were analyzed, retrospectively, over a 5-yr period (September of 1988 to August of 1993). During this period, 1666 endoscopic retrograde cholangiopancreatographic studies were performed and pancreatic-biliary ascariasis was diagnosed in 300 patients (18%). RESULTS: The most common presenting symptom was abdominal pain, seen in 98% of patients (294 patients). Complications observed were ascending cholangitis (48 patients; 16%), acute pancreatitis (13 patients; 4.3%), and obstructive jaundice (4 patients; 1.3%). History of worm emesis was present in 25% of patients (76 patients). Most patients (240 patients; 80%) had previously undergone a cholecystectomy or an endoscopic sphincterotomy (232 patients; 77%). Worms were successfully extracted endoscopically in all except two patients, and there were no procedure-related complications. CONCLUSIONS: In endemic countries, ascariasis should be suspected in patients with pancreatic-biliary disease, especially if a cholecystectomy or sphincterotomy has been performed in the past. Endoscopic management results in rapid resolution of symptoms and prevents development of complications. 相似文献
123.
BACKGROUND: All National health programmes are implemented through the Primary Health Centre staff. Targets for the year 2000 A.D. have been fixed for different programmes. Some programmes are getting more emphasis, perhaps at the cost of others. The study area has already achieved most of the targets set for 2000 A.D. Studying the time utilisation pattern of the workers of these PHCs can give valuable information for planning of working of other PHCs. OBJECTIVE: To study the time utilisation pattern of the staff of the two PHCs run by Centre for Community Medicine, AIIMS. METHODS: The multipurpose workers (MPWs) and the health assistants (HAs) were accompanied by investigators and information collected regarding their utilisation of time in the field. The Medical Officers were asked to maintain a diary from which this information was collected RESULTS: The MPWs spend about 3.3 minutes in each house. Child care (immunisation, Vit. A and folifer distribution) is the main activity being carried out by both male as well as female worker. Other important activities for male worker are: family welfare (18%), malaria work (11%) and collection of vital statistics (10%). For the female worker Antenatal care (25%) and family welfare (20%) were other important activities. For the HAs also child care was an important activity. However for the male HA malaria related work was the most important. The Medical Officer spends about 60% of this time in administrative and supervisory work. CONCLUSIONS: Immunisation programme is getting the maximum input from workers, which is reflected in > 90% coverage of all vaccines. Family Welfare and Tuberculosis activity are not getting the emphasis which they deserve. Some rethinking about the strategy is essential if all round progress in achieving the targets for the year 2000 A.D. is to be made. 相似文献
124.
125.
Waveband switching in optical networks 总被引:20,自引:0,他引:20
The rapid advances in dense wavelength-division multiplexing technology with hundreds of wavelengths per fiber and worldwide fiber deployment have brought about a tremendous increase in the size (i.e., number of ports) of photonic cross-connects, as well as in the cost and difficulty associated with controlling such large cross-connects. Waveband switching (WBS) has attracted attention for its practical importance in reducing the port count, associated control complexity, and cost of photonic cross-connects. We show that WBS is different from traditional wavelength routing, and thus techniques developed for wavelength-routed networks (including, for example, those for traffic grooming) cannot be directly applied to effectively address WBS-related problems. We describe two multigranular OXC architectures for WBS. By using the multilayer MG-OXC in conjunction with intelligent WBS algorithms for both static and dynamic traffic, we show that one can achieve considerable savings in the port count. We also present various WBS schemes and lightpath grouping strategies, and discuss issues related to waveband conversion and failure recovery in WBS networks. 相似文献
126.
We report a 51-year-old woman with alopecia caused by sarcoidosis. The lesion enlarged within 4 years and only repeated biopsies enabled the diagnosis. The medical work-up revealed that the patient had asymptomatic pulmonary involvement. Scarring alopecia is a rare complication of sarcoidosis and biopsy from the active margin may lead to the diagnosis. 相似文献
127.
Dwarakanath N. Geerpuram Anand S. Mani Vidhya Shankar Baskaran 《Journal of Electronic Materials》2004,33(11):1269-1273
The behavior of narrow permalloy square rings under the influence of a magnetic field was studied using magnetic force microscopy
(MFM). Two stable states of opposite polarity at remanence and simple switching were observed. We propose a design for the
hard layer of magnetic random access memory (MRAM) that uses these states in square rings for data storage. 相似文献
128.
UWB:个人无线局域网络的高速公路多频带OFDM VS.直接序列DS--两大技术特性的综合剖析 总被引:1,自引:0,他引:1
Anuj Batra Jaiganesh Balakrishnan Anand Dabak 《电子与电脑》2005,(8):121-125
大约3年前,美国联邦通信委员会发布一份历史性的Report&Order报告,将3.1GHz~10.6GHz的7,500MHz频谱配置给超宽带(UltraWideBand,UWB)装置使用。这份报告为产业和学术界带来许多创新与技术进步的机会,业界也纷纷成立各种组织,例如多频带OFDM联盟(Multi-band OFDM Alliance)、UWB论坛以及IEEE802.15.3a特别工作小组,希望为UWB技术建立共同的标准。 相似文献
129.
Water-soluble models of ligand-gated ion channels would be advantageous for structural studies. We investigated the suitability of three versions of the N-terminal extracellular domain (ECD) of the alpha7 subunit of the nicotinic acetylcholine receptor (AChR) family for this purpose by examining their ligand-binding and assembly properties. Two versions included the first transmembrane domain and were solubilized with detergent after expression in Xenopus oocytes. The third was truncated before the first transmembrane domain and was soluble without detergent. For all three, their equilibrium binding affinities for alpha-bungarotoxin, nicotine, and acetylcholine, combined with their velocity sedimentation profiles, were consistent with the formation of native-like AChRs. These characteristics imply that the alpha7 ECD can form a water-soluble AChR that is a model of the ECD of the full-length alpha7 AChR. 相似文献
130.
Parul Gupta Anand GhosalkarSaroj Mishra Tapan Kumar Chaudhuri 《Journal of Bioscience and Bioengineering》2009,107(2):102-107
A major portion of the over expressed yeast mitochondrial aconitase, a large 82 kDa monomeric TCA cycle enzyme, in Escherichia coli led to the formation of inclusion bodies. Bacterial chaperonin GroEL mediated the correct folding of aconitase with the assistance of its co-chaperonin GroES in an ATP dependent manner. Till date the chaperonin assisted folding of aconitase was limited to the shake flask studies with relatively low yields of folded aconitase. No attempt had yet been made to enhance the yield of chaperone mediated folding of aconitase using a bioreactor. The current report deals with the effect of co-expression of GroEL/GroES in the production of soluble, biologically active recombinant aconitase in E. coli by cultivation in a bioreactor at different temperatures under optimized conditions. It revealed that the yield of functional aconitase was enhanced, either in presence of co-expressed GroEL/ES or at low temperature cultivation. However, the outcome from the chaperone assisted folding of aconitase was more pronounced at lower temperature. A 3-fold enhancement in the yield of functional aconitase from the bioreactor based chaperone assisted folding was obtained as compared to the shake flask study. Hence, the present study provides optimized conditions for increasing the yield of functional aconitase by batch cultivation in a bioreactor. 相似文献