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101.
The effect of variations in composition on optical properties was studied. The index of refraction is lowered by the substitution of fluorine and alumina for silica; the reciprocal dispersion, however, is increased by fluorine and lowered by alumina so that fluorine and alumina can be balanced against each other to give almost any desired optical properties within the field investigated, that is, in the range of 1.46 to 1.50 for index of refraction and 63 to 70 for the reciprocal dispersion. 相似文献
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Heinrichs R. Walter; Miles Ashley A.; Smith Diana; Zargarian Tannaz; Vaz Stephanie McDermid; Goldberg Joel O.; Ammari Narmeen 《Canadian Metallurgical Quarterly》2008,22(3):321
The existence of small numbers of schizophrenia patients with superior ability in specific cognitive domains is implied by meta-analytic evidence as well as by occasional empirical reports. The authors identified 25 patients with superior (i.e., ≥90th percentile) ability on the Vocabulary subtest of the Wechsler Adult Intelligence Scale 3rd edition (Wechsler, 1997). These cognitively advantaged patients were compared with 22 healthy participants performing at the superior level and with 126 schizophrenia patients and 50 healthy participants scoring below the superior range. Verbally superior schizophrenia patients and verbally superior healthy participants had similar cognitive profiles and life skills performance, but diverged markedly in terms of independent \"real-world\" functioning. Verbally superior patients significantly outperformed more typical patients in other aspects of cognitive performance, life skills, and support requirements. However, severity of positive and negative symptoms was equivalent in the patient groups. Detailed biobehavioral study of cognitively exceptional patients may offer new insights into mechanisms mediating psychotic disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Fabien Choffat Paul Smith Walter Caseri 《Advanced materials (Deerfield Beach, Fla.)》2008,20(11):2225-2229
Organometallic polymers comprising a backbone of covalently connected metal atoms can be regarded as molecular metal wires surrounded by a jacket of organic matter. Such polymers are rare and their materials properties are largely unexplored. Here, we report on polystannanes, (SnR2)n, that is, polymers with a backbone of tin atoms, which are synthesized by dehydropolymerization of dialkylstannanes (H2SnR2) with the catalyst [RhCl(PPh3)3]. The polystannanes feature reversible phase transitions into liquid‐crystalline states, remarkably, even below room temperature, and, interestingly, oriented either parallel or perpendicular to external driving forces, depending on the length of the alkyl substituents. 相似文献
106.
Yanka Jeliazova Michael Kayser Beate Mildner Achim Walter Hassel Detlef Diesing 《Thin solid films》2006,500(1-2):330-335
The dielectric breakdown of thin (d = 3–4 nm) aluminium and tantalum oxide films was investigated by means of current voltage plots in metal/insulator/metal systems. Dielectric breakdown field strengths, EDB, of 0.6 GV m− 1 were found for both oxide types at room temperature. Differences appear in the temperature dependence of EDB. Tantalum oxide films show an unchanged breakdown behaviour for temperatures up to 420 K while aluminium oxide films lose already 80% of their EDB value in the same temperature range. Time-resolved investigations of the electric breakdown revealed intermediate states of both oxide types which were stable for several ms being characterized by an enhanced tunnel current. The breakdown voltage clearly scales with the oxide thickness for both oxide types. 相似文献
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109.
Workplace AIDS training is a recent addition to many corporations' occupational health agenda. However, little is known about the objectives, content, and practices of AIDS training programs. A survey of 126 workplace AIDS trainers was conducted to determine the impact of the trainer's organizational affiliation (in-house, consultant, union, etc.) and personal motives on training program objectives, content, and practices. Results indicate that the organizational affiliation of trainers is significantly related to training objectives, topics, and practices, whereas strong personal motives for becoming an AIDS trainer is significantly associated with an emphasis on more controversial content areas and training practices. Findings are discussed in terms of applicability to other values-oriented training topics, applications to practice, and future research needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.
Vinyl chloride (VC) workers are known to be at risk for development of liver angiosarcoma, a rare tumor. Previously, more than 80% of VC workers with liver angiosarcoma have been found to have an Asp-13 c-Ki-ras oncogene mutation, and more than 50% of VC-exposed workers without liver tumors were found to have Asp13-Ki-ras oncoprotein in their plasma. Some workers in Taiwan had also been exposed to VC, and some have contracted liver tumors. In this study, we used enhanced chemiluminescence Western blotting to detect Asp13-p21-Ki-ras in the sera of VC-exposed workers in Taiwan. There were 14 of 113 (12.4%) VC workers positive for the Asp13-Ki-ras oncoprotein in plasma, but 0 of 18 controls were positive. There were 10 of 69 (14.5%) plasma-positives among the more highly exposed (> 1000 ppm-months) workers and 4 of 48 (9.1%) plasma-positives among the lesser exposed (< or = 1000 ppm-months). Compared with the unexposed controls, the odds ratios (and 95% confidence intervals [CI]) for plasma-positivity were 4.11 (95% CI = 0.21, 80.4) in the lower-exposed workers and 6.53 (95% CI = 0.37, 116.9) in the higher-exposed workers, and there was a linear trend between exposure and plasma-positivity (P = 0.073). After adjusting for age and drinking status, the odds ratios (and 95% CIs) were 1.64 (95% CI = 0.17, 15.8), and 2.65 (95% CI = 0.42, 16.8), respectively, and there was a significant linear trend between exposure and plasma-positivity (P = 0.048). In summary, Asp13-Ki-ras oncoprotein can be found in the plasma of VC workers in Taiwan, and a significant dose-response relationship exists between plasma oncoprotein expression and VC exposure. 相似文献