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排序方式: 共有383条查询结果,搜索用时 62 毫秒
71.
A. Mitchell Advanced Materials Research Laboratory University of British Columbia Vancouver BC Canada 《金属学报(英文版)》1999,12(4):283-296
1.IntroductionDevelopmentsinrotatingpartsoverthepastdecadehavenotseentheextensiveintroductionofnewmaterials,butratherthemorerigorousapplicationofexistingalloysasourunderstandingoftheserviceconditionsandmechanicalrequirementshasbecomedeeper.Thetwoesse… 相似文献
72.
Sebeková K Boor P Valachovicová M Blazícek P Parrák V Babinská K Heidland A Krajcovicová-Kudlácková M 《Molecular nutrition & food research》2006,50(9):858-868
Conditions predisposing to metabolic syndrome (MetS) are associated with increased oxidative stress and inflammation. We studied, in vegetarians (n = 90) and omnivores (n = 46), the impact of the dietary regimen on the occurrence of MetS risk factors (RFs: BMI, blood pressure, glucose metabolism and lipid profile) in relation to oxidative status (advanced glycation end products (AGEs), advanced oxidation protein products (AOPPs), malondialdehyde, ferric reducing ability of plasma, vitamins A, E, C, beta-carotene and superoxide dismutase activity) and microinflammation (C-reactive protein, leukocytes and neopterin). The proportion of subjects without/positive for one or two MetS RFs was comparable between the groups. From the components of MetS only immunoreactive insulin levels differed significantly (95% CI: omnivores: 5.0-7.1 microU/mL, vegetarians: 4.5-5.4, p = 0.03). Omnivores had lower AOPP (omnivores: 0.29-0.36 micromol/g albumin, vegetarians: 0.36-0.52, p = 0.01) and beta-carotene levels than vegetarians, they consumed more calories, proteins, fat and saturated fatty acids, and less fibres, beta-carotene and vitamin C. Multiple regression analysis revealed vitamin E and AOPP levels as the most important independent determinants of MetS RFs. The vegetarian diet seems to exert beneficial effects on MetS RFs associated microinflammation. Whether the vegetarian diet may counteract the deleterious effects of elevated AOPPs and AGEs, remains to be elucidated. 相似文献
73.
钻柱振动声波录井技术方法及应用实例 总被引:1,自引:0,他引:1
钻柱振动声波录井技术DVL(Drillstring Vibro-acoustic Logging)经过多年的室内研究和现场验证,已经取得了可喜成果,为了进一步完善其解释评价方法,该课题尚需要在现场试用中不断地深化应用研究,近期又一次开展了现场试验。简介了该技术的工作原理、配套硬件构成和无线数据传输系统的特点。结合现场应用实例.阐述了DVL技术发展最新的理论分析方法和研究成果;给出了DVL技术分析中的相关分析法和信号能量计算法;列举了频聚法、能聚法和归一化数据处理方法的理论公式和其应用方法。通过应用实例证实,依据DVL频谱图、频聚和能聚曲线、能量和相位差曲线,能有效地识别地层岩性,划分地层和油藏。同时在钻具工况的分析、辅助识别上能起到了一定的作用,为DVL技术的发展奠定了理论基础。 相似文献
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75.
Youngwoo Nam Jai Seung Yoo Yung Woo Park Niclas Lindvall Thilo Bauch August Yurgens 《Carbon》2012,50(15):5562-5568
We measured the Aharonov-Bohm (AB) effect in graphene rings with superconducting-(Al) and normal-metal (Au) mirrors. The mirrors were deposited either on additional stubs connected to the rings in the transverse direction or on the ring bias lines. A significant enhancement of the visible phase coherence was observed in the latter case, in which we observed even the third harmonic of the AB oscillations. The superconductivity of the mirrors appears to be unimportant for the improved coherence in graphene. A large Fermi energy mismatch between graphene and the mirror material is sufficient for this effect. In addition, a transport gap was observed in our graphene structures at the gate voltage close to the Dirac point. The value of the gap can be reproduced by assuming the occurrence of Coulomb blockade effects in graphene. 相似文献
76.
冯青 《沈阳建筑工程学院学报(自然科学版)》1992,8(1):43-48
根据人的精神需要,对体育馆内部空间设计和外部造型处理进行了分析和研究。强调设计时必须充分体现人在物质和精神上的平衡,考虑人的因素是空间处理的重点。 相似文献
77.
Chopra Mohit P.; Landes Reid D.; Gatchalian Kirstin M.; Jackson Lisa C.; Buchhalter August R.; Stitzer Maxine L.; Marsch Lisa A.; Bickel Warren K. 《Canadian Metallurgical Quarterly》2009,17(4):226
During a 12-week intervention, opioid dependent participants (N = 120) maintained on thrice-a-week (M, W, F) buprenorphine plus therapist and computer-based counseling were randomized to receive: (a) medication contingencies (MC = thrice weekly dosing schedule vs. daily attendance and single-day 50% dose reduction imposed upon submission of an opioid and/or cocaine positive urine sample); (b) voucher contingency (VC = escalating schedule for opioid and/or cocaine negative samples with reset for drug-positive samples); or (c) standard care (SC), with no programmed consequences for urinalysis results. VC resulted in better 12-week retention (85%) compared to MC (58%; p = 0.009), but neither differed from SC (76% retained). After adjusting for baseline differences in employment, and compared to SC, the MC group achieved 1.5 more continuous weeks of combined opioid/cocaine abstinence (p = 0.030), while the VC group had 2 more total weeks of abstinence (p = 0.048). Drug use results suggest that both the interventions were efficacious, with effects primarily in opioid rather than cocaine test results. Findings should be interpreted in light of the greater attrition associated with medication-based contingencies versus the greater monetary costs of voucher-based contingencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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80.
Michelle Acosta August Buchhalter Alison Breland Duncan Hamilton Thomas Eissenberg 《Nicotine & tobacco research》2004,6(4):615-620
Biomarkers such as carbon monoxide (CO) and cotinine (a nicotine metabolite) are used in tobacco cessation studies to assess smoking status. CO is easy to assess, is inexpensive, and provides immediate results. However, the short half-life of CO may limit its ability to identify smokers who have abstained for several hours. Quantitative methods (e.g., gas chromatography/mass spectrometry, or GC/MS) for measuring urine cotinine, which has a longer half-life, are valid and reliable, though costly and time consuming. Recently developed semiquantitative urine cotinine measurement techniques (i.e., urine immunoassay test strips, or ITS) address these disadvantages, though the value of ITS as a means of identifying abstaining smokers has not been evaluated. The present study examined ITS as a measure of smoking status in temporarily abstaining smokers. A total of 236 breath and urine samples were collected from smokers who participated in two separate studies involving three independent, 96-hr (i.e., Monday-Friday), Latin-square-ordered, abstinence or smoking conditions; a minimum 72-hr washout separated each condition. Each urine sample was analyzed with GC/MS and ITS. Under these study conditions, CO demonstrated moderate sensitivity (83.1%) and strong specificity (100%), whereas ITS assessment showed strong sensitivity (98.5%) and weak specificity (58.5%). In this study of short-term abstinence, ITS classified as nonabstinent nearly half of the samples collected from abstaining smokers. However, it classified nearly all nonabstinent smokers as currently smoking. Validation of ITS using GC/MS results from smokers undergoing more than 96 hr of abstinence may be valuable. 相似文献