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991.
Regression analyses of field study data from 27 nursing subunits supported the hypothesis that a simple measure of fit between technology and structure is better predictor of quality of care than either technology or structure alone, or the two together. The results of this study were thus consistent with the growing body of congruency literature, and they suggest that a simple measure of structure may be quite useful in such research.  相似文献   
992.
Effective December 1987 and January 1988, the maximum speed limit on rural limited access highways in Michigan was raised from 55 mph to 65 mph. This study examined the effects of the raised limit on injury morbidity and mortality. A multiple time-series design was used, comparing roads where the speed limit was raised with roads where the limit remained unchanged. Data were collected on numbers and rates of automobile crashes, injuries, and deaths from January 1978 through December 1988. Time-series intervention analyses were conducted to estimate effects associated with the speed limit change while controlling for long-term trends, seasonal cycles, and other patterns. Statistical controls were also included for major factors known to influence crash and injury rates. Results revealed significant increases in casualties on roads where the speed limit was raised, including a 19.2% increase in fatalities, a 39.8% increase in serious injuries, and a 25.4% increase in moderate injuries. Fatalities also increased on 55 mph limited access freeways, suggesting that the 65 mph limit may have spillover effects on segments of freeways where the limit was not changed. No significant changes in fatalities or injuries were found on other types of roads. The increased convenience of reduced travel time with the higher speed limit is obtained at a significant cost in terms of injury morbidity and mortality.  相似文献   
993.
This paper examines the evolution of the role, structure, and orientation of SEMATECH in supporting the competitiveness of U.S. semiconductor industry between the late 1980s and the late 1990s. SEMATECH overcame its early challenges and succeeded by shifting its emphasis from horizontal (competitive) to vertical (precompetitive) collaboration, and then to a combined horizontal/vertical form (competitive). This evolutionary path in structure and strategy has broad implications for future relations between SEMATECH and the semiconductor industry as a whole, as well as industry R&D consortia in general. These implications are explored by detailing recent strategic developments at SEMATECH and their relationship to the market environment and structure in the global semiconductor manufacturing industry. This analysis is then extended to explore the implications for strategic research partnerships in other industries, which share particular salient characteristics with the semiconductor industry.  相似文献   
994.
A novel hydrophobic monomer was synthesized from the acetoacetic ester and dodecylamine by condensation reaction in mild conditions. The modification by the dodecyl groups monomer was involved in the Michael addition reaction with acrylic (or methacrylic) acid followed by radical polymerization. Both linear and crosslinked novel betaine‐type polyampholytes bearing hydrophobic “tail” and hydrophilic “head” were obtained. The linear polymer was characterized by viscometry, FTIR, and Raman spectroscopy. Swelling–shrinking behavior of linear and crosslinked samples was studied in water–DMF and water–DMSO mixtures. The applicability of hydrophobically modified polybetaines as pour point depressants (fluidity improvers) was also demonstrated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1042–1048, 2004  相似文献   
995.
Investigations on development of a macrokinetics approach were generalized to the analysis of fast chemical reactions, mainly using cationic polymerization of isobutylene as an example, which is a new class of liquid‐phase processes. The removal of diffusional constraints on polymer synthesis, by intensification of turbulent mixing in the reaction zone, makes it possible to calculate the kinetic parameters of polymerization and polymer‐analogous reactions, to optimize the molecular characteristics of polymeric products obtained, and to control the character of the process as a whole. The laws pertaining to the progression of fast processes are considered for the synthesis of separate polymers, in particular stereoregular polydienes, ethylene–propylene copolymers, and chlorobutyl rubber. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 613–624, 2004  相似文献   
996.
997.
The nature of the authors' observational coding, both as a process and as a strategy, represents one of the clearest expressions of their philosophy of science and approach to clinical model building. They believe that there is no support for prioritizing one vs another observational coding approach. More important, they assert that a dialogue among various perspectives is essential for the knowledge base to expand and for clinical models to develop. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
998.
999.
涉足尖端技术研究工作的芯片制造商正在把无数新材料和奇特的器件结构结合起来,用于65nm及更低节点的量产。同时他们发现,在这些研究上的努力生产的结果还包括目前必须着手解决各器件各个层上出现的  相似文献   
1000.
In order to study the promoting effect of polycations on the cobalt(II)phthalocyanine-tetrasodiumsulphonate (CoPc(NaSO3)4)-catalysed autoxidation of thiols, it is imperative to know the molecular weight dependence of the polymer. Monodisperse oligomers can often supply a lot of information. To elecidate the mechanism of the promoting effect of 2,4-ionene, a poly(quaternary ammonium)salt, on the CoPc(NaSO3)4-catalysed autoxidation of 2-mercaptoethanol, a series of monodisperse 2,4-ionene oligomers were prepared. Trimeric 2,4-ionenes, containing two quaternary ammonium groups separated by four methylene groups, showed a high co-catalytic activity, and active Co-aggregates were detected with visible light spectroscopy. The spectroscopic behaviour was in close agreement with that of high molecular 2,4-ionene/CoPc(NaSO3)4 complexes. In order to achieve this aggregation several oligomeric ionenes have to act concertedly. If the distance between the ionic sites is short the trimer acts as a simple salt in stablizing the aggregates. With respect to the catalytic activity the optimum polycation/catalyst ratio, expressed as the N+/Co ratio, decreased with increasing chain lenght and reached a constant level of 50 at a 2,4-ionene nonamer. For the trimers and pentamers this ratio is affected by the type of end-group. All synthesized 2,4-ionene oligomers exhibited excellent co-catalytic properties at the optimum N+/Co ratio, with maximum turnover frequencies of 4600 mol thiol/(mol Co s), i.e. 50 times higher than those obtained for the polymer-free system. In the case of monodisperse 2,4-ionene pentamer with bromo end-groups, double Michaelis–Menten kinetics were observed, as also was exhibited by high molecular weight ionene.  相似文献   
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