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排序方式: 共有1236条查询结果,搜索用时 31 毫秒
101.
Lin L.Y. Goldstein E.L. Simmons J.M. Tkach R.W. 《Photonics Technology Letters, IEEE》1998,10(10):1425-1427
Optical-layer crossconnects with high port count appear to be emerging as key elements for provisioning and restoration in future wavelength-division-multiplexed networks. We demonstrate here a means of achieving high-density optical crossconnects utilizing free-space micromachined optical switches that exploit connection-symmetry in core-transport networks. The micromachined polygon switches proposed here are strictly nonblocking. Measured insertion losses of 3.1-3.5 dB for a 16×16 (8×8 bidirectional) switch suggest the promise of scaling to large port count 相似文献
102.
GT Simmons 《Canadian Metallurgical Quarterly》1997,42(4):678-681
Tandem projectiles are unusual events which can cause erroneous case interpretations if one is unfamiliar with them. This paper presents two such cases. The first case involved three .32 caliber bullets, two of which became lodged in a revolver barrel because of faulty ammunition. A third fired bullet subsequently pushed itself and the lodged bullets out of the barrel resulting in a single entrance wound with three bullets in the body. The second case involved a 20 gauge shotgun shell which apparently was inadvertently loaded into a 12 gauge shotgun. This resulted in an unusual entrance wound and unusual X-rays with fragments of the 20 gauge shotgun shell, as well as 12 gauge shotgun shell wadding, being removed from the same wound. The pertinent findings in such cases are discussed so that they may be correctly identified when they occur. 相似文献
103.
Ge Xiaojia; Kim Irene J.; Brody Gene H.; Conger Rand D.; Simons Ronald L.; Gibbons Frederick X.; Cutrona Carolyn E. 《Canadian Metallurgical Quarterly》2003,39(3):430
Effects of early physical maturation and accelerated pubertal changes on symptoms of major depression were examined in 639 African American children. Three rival hypotheses, early timing, off-time, and stressful change, were tested using 2 waves of data (mean ages = 11 and 13 years). The pubertal effect operates differently according to children's gender and age. For girls, early maturation was consistently associated with elevated levels of depressive symptoms. For boys, early maturers manifested elevated levels of depression only at age 11, but these symptoms subsided by age 13. Boys who experienced accelerated pubertal growth over time displayed elevated symptom levels. Results support the early timing hypothesis for girls and the stressful change hypothesis for boys. Time at assessment is critical when examining boys' pubertal transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
M Kirkwood D Simmons T Weblemoe J Voyle D Richards 《Canadian Metallurgical Quarterly》1997,110(1055):415-417
AIMS: To assess knowledge and opinions of diabetes among rural Maori elders and spokespersons. METHODS: Interviews were conducted in rural South Auckland. Subjects were identified through their affiliation with one marae (meeting house), residence near the marae and being recognised locally as either male (kaumatua) or female (kuia) elders or spokespersons. The main researcher was a kuia chosen by and from within the local community. Interviews were conducted with 43/44 (98%) subjects identified. RESULTS: While specific diabetes knowledge was low, diabetes was seen, along with cancer, as one of the two major health issues for Maori. Results need to be understood in the context of the holistic understanding of health by Maori. CONCLUSION: The recognition of diabetes as a major health problem was accompanied by a call for diabetes education in a form that will generate interest and participation by Maori. It is timely for the introduction of marae based diabetes awareness and sustained exercise programmes as part of a diabetes prevention and control strategy among Maori communities where diabetes risk is high. 相似文献
105.
The following article is Part II of a three-part series on the use of polymer insulating materials in outdoor insulation applications. Despite three decades of service history, polymer insulation materials do not have the same level of standardization as porcelain. As with any technology that is not well standardized, misunderstanding and confusion result, which can influence user selection and application. The objective of this series is to review the benefits of polymer insulating materials. Part II discusses the factors that affect the engineering of materials and addresses the validity of some industry perceptions. A future article will explore some of the material science aspects of silicone elastomer materials by using the case of a hybrid insulator design 相似文献
106.
107.
Yung-Sheng Huang Dave E. Mills Ron P. Ward David F. Horrobin Valerie A. Simmons 《Lipids》1989,24(7):565-571
Weanling male spontaneously hypertensive (SHR) and normotensive (WKY) rats were maintained on a fat-free semisynthetic diet
and killed at various intervals. The effects of fat-depletion on the appearance of essential fatty acid (EFA) deficiency symptoms,
the progressive changes of major fatty acids in plasma, liver, heart, and kidney phospholipids (PL), and in skin total lipids
were compared between these two strains. After five weeks on the diet, the slower growth and the appearance of EFA deficiency
symptoms became evident in SHR. In general, fat-depletion reduced the levels of n−6 fatty acids, whereas it increased those
of 20∶3n−9. However, the fat-depletion induced reduction of 18∶2n−6 in heart PL and 20∶4n−6 in kidney, while the elevation
of 20∶3n−9 in plasma, heart, and kidney PL were greater in WKY than in SHR. As a result, the elevation of biochemical EFA
deficiency index—20∶3n−9/20∶4n−6 ratio—was greater in WKY than in SHR. In comparison with WKY, the concentrations of liver
triacylglycerols and the weights of adipose tissues in SHR were reduced to a greater extent, indicating an active catabolism
of triacylglycerols in SHR. This study suggests that the earlier appearance of morphological symptoms of EFA deficiency in
SHR was not associated with the reducing n−6 EFA levels or with an elevation of triene/tetraene ratio, but possibly to a reduced
supply of n−6 EFA for skin prostaglandin synthesis. 相似文献
108.
Andrew B. C. Yu Glenn Portmann Daryl Simmons 《Drug development and industrial pharmacy》1995,21(16):1827-1840
A hydrolytic acid and base catalyzed ring opening reaction has been demonstrated for a 1,2,4-oxadiazole antiviral compound (WIN 63843) resulting mainly in an amidoxime product. Decomposition products and related impurities were detected using a gradient HPLC method. The hydrolysis reaction was first-order for 35% ethanol/buffer solutions in a 50°C chamber or a light cabinet (1000 ft-candles), the greatest stability being between pH 4 and 6. Furthermore, increasing ethanol concentrations resulted in a great decrease in reaction rates. Therefore, for oral or aerosol solution formulations, light protection, pH control between 4 and 6 and the highest permissible ethanol concentrations would be advantageous. This study has shown that the highly electronegative trifluoromethyl group at the 5 position increases the lability of a 1,2,3-oxdiazole compound. 相似文献
109.
Johannes Staguhn Dominic Benford Eli Dwek Gene Hilton Dale Fixsen Kent Irwin Christine Jhabvala Attila Kovacs Samuel Leclercq Stephen Maher Tim Miller S. Harvey Moseley Elmer Sharp Edward Wollack 《Journal of Low Temperature Physics》2014,176(5-6):829-834
We present the main design features for the GISMO-2 bolometer camera, which we build for background-limited operation at the IRAM 30 m telescope on Pico Veleta, Spain. GISMO-2 will operate simultaneously in the 1 and 2 mm atmospherical windows. The 1 mm channel uses a \(32 \times 40\) TES-based backshort under grid (BUG) bolometer array, the 2 mm channel operates with a \(16 \times 16\) BUG array. The camera utilizes almost the entire full field of view provided by the telescope. The optical design of GISMO-2 was strongly influenced by our experience with the GISMO 2 mm bolometer camera, which is successfully operating at the 30 m telescope. GISMO is accessible to the astronomical community through the regular IRAM call for proposals. 相似文献
110.
The National Energy Strategy of the U.S. is designed to expand through federal policies the fuel and technology choices available to industry, utilities, and other energy users. It also promotes policies to encourage balanced integration of energy, economic, and environmental options in the selection of technologies for application in the marketplace. Consideration of each of these factors, separately and together, favors geothermal energy in many industrial applications. It is the policy of the Department of Energy to support growth in all uses of geothermal energy through focused R & D to improve technologies for its economic exploitation. 相似文献