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991.
Results of calorimetric investigations performed on two groups of glasses, viz. As-Te-Se and Ge-As-Se, are described. The
glass transition temperatureT
g and specific heat at constant pressureC
p
of these two families of glasses have been determined using a differential scanning calorimeter. The composition dependence
of glass transition temperature and variation of heat capacity during transition are discussed. 相似文献
992.
Landscape visualizations: Applications and requirements of 3D visualization software for environmental planning 总被引:1,自引:0,他引:1
This paper presents the findings of an investigation into the role and use of landscape visualization software for landscape and environmental planning in Germany. It examines the challenges and requirements of 3D visualization technology and its potential for application in landscape and environmental planning. Relevant literature and comparable surveys are reviewed in order to determine the current state of affairs, and the general and international relevance of the results is assessed.In 2000, a survey of user requirements for 3D landscape simulation software, including the demand for specific features, was conducted within the framework of a feasibility study for a visualization tool. As part of the German-wide survey, comprehensive questionnaires were sent to 1044 respondents from a pool of private landscape planning consultancies, freelance landscape architects, and public planning and environmental authorities.The survey showed that 3D landscape visualization has a positive image in Germany, both among user and non-user groups of visualization tools. Twenty-eight percent of private consultancies and freelance landscape architects, as well as 7% of public authorities, stated that they already used 3D simulation software. Those respondents who did not use 3D simulation software cited insufficient computer equipment, lack of technical expertise of planners and cost-related aspects as reasons for not yet having adopted the technology. “Ease of learning” and “interoperability” are deemed to be the most important features of 3D simulation software, whereas factors such as “high interactivity”, “representability of ecological processes” and “photo-realism” are, surprisingly, regarded as much less important.Users of 3D visualization software are particularly concerned by insufficient representation of plants and habitats in simulations. Looking to the future, the vast majority of respondents (91%) expect increased benefits for landscape planning from 3D visualization software, are convinced of the advantages of the technology, and are eager to integrate 3D landscape visualizations into their working practices. 相似文献
993.
Sallis James F.; Nader Philip R.; Broyles Shelia L.; Berry Charles C.; Elder John P.; McKenzie Thomas L.; Nelson Julie A. 《Canadian Metallurgical Quarterly》1993,12(5):390
22 potential correlates of children's physical activity were examined. 201 Mexican-American and 146 Anglo-American families with 4-yr-old children were studied. Children's physical activity was directly observed in the evening at home on 4 visits for 1 hr each time. Anglo-American children and male children were found to be more active. Demographic variables explained 11% of the variance in children's physical activity. After adjusting for demographics, 3 children's variables and 6 social-family variables did not account for significantly more variance. Five environmental variables accounted for 11% additional variance. Variables observed concurrently with physical activity, such as time spent outdoors and prompts to be active, were highly associated with children's physical activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
994.
995.
Laminar mixing of shear thinning fluids in a SMX static mixer 总被引:1,自引:0,他引:1
Flow and mixing of power-law fluids in a standard SMX static mixer were simulated using computational fluid dynamics (CFD). Results showed that shear thinning reduces the ratio of pressure drop in the static mixer to pressure drop in empty tube as compared to Newtonian fluids. The correlations for pressure drop and friction factor were obtained at ReMR?100. The friction factor is a function of both Reynolds number and power-law index. A proper apparent strain rate, area-weighted average strain rate on the solid surface in mixing section, was proposed to calculate pressure drop for a non-Newtonian fluid. Particle tracking showed that shear thinning fluids exhibit better mixing quality, lower pressure drop and higher mixing efficiency as compared to a Newtonian fluid in the SMX static mixer. 相似文献
996.
Savage Robert S.; Abrami Philip; Hipps Geoffrey; Deault Louise 《Canadian Metallurgical Quarterly》2009,101(3):590
This study reports a randomized controlled trial evaluation of a computer-based balanced literacy intervention, ABRACADABRA (http://grover.concordia.ca/abra/version1/abracadabra.html). Children (N = 144) in Grade 1 were exposed either to computer activities for word analysis, text comprehension, and fluency, alongside shared stories (experimental groups), or to balanced literacy approaches delivered by their classroom teachers (control group). Two computer-based interventions—a phoneme-based synthetic phonics method and a rime-based analytic phonics method—were contrasted. Children were taught 4 times per week for 12 weeks in small groups. There were significant improvements in letter knowledge in the analytic phonics program and significant improvements in phonological awareness, listening comprehension, and reading comprehension at immediate posttest and in phonological awareness and reading fluency at a delayed posttest in the synthetic phonics program. Effect size analyses confirmed that both interventions had a significant impact on literacy at both posttests. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
997.
Williams S. Lloyd; Kinney Philip J.; Harap Stephen Todd; Liebmann Marc 《Canadian Metallurgical Quarterly》1997,106(4):511
The authors examined the occurrence of theoretically derived patterns of thinking in 74 agoraphobic participants as they drove alone or tolerated an enclosed place. During the increasingly scary tasks in a behavioral test hierarchy, participants responded to a periodic beep by stating aloud what they were thinking at that moment, yielding more than 1,800 tape-recorded statements. Content analyses revealed that participants were mainly preoccupied with their current anxiety (expressed in 29% of the statements) and with their self-efficacy (15%). Despite participants' mounting feelings of anxiety, fewer than 1% of their statements expressed a thought of danger or an anticipation of future anxiety or panic. The rarity of danger thoughts poses an explanatory challenge for all cognitive theories of phobia and especially for the perceived danger theory of A. T. Beck (1976) and A. T. Beck, G. Emery, and R L. Greenberg (1985). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
998.
Rajeev Rastogi Philip Bohannon James Parker Avi Silberschatz S. Seshadri S. Sudarshan 《Distributed and Parallel Databases》1998,6(1):41-71
In this paper we present recovery techniques for distributed main-memory databases, specifically for client-server and shared-disk architectures. We present a recovery scheme for client-server architectures which is based on shipping log records to the server, and two recovery schemes for shared-disk architectures—one based on page shipping, and the other based on broadcasting of the log of updates. The schemes offer different tradeoffs, based on factors such as update rates.Our techniques are extensions to a distributed-memory setting of a centralized recovery scheme for main-memory databases, which has been implemented in the Dalì main-memory database system. Our centralized as well as distributed-memory recovery schemes have several attractive features—they support an explicit multi-level recovery abstraction for high concurrency, reduce disk I/O by writing only redo log records to disk during normal processing, and use per-transaction redo and undo logs to reduce contention on the system log. Further, the techniques use a fuzzy checkpointing scheme that writes only dirty pages to disk, yet minimally interferes with normal processing—all but one of our recovery schemes do not require updaters to even acquire a latch before updating a page. Our log shipping/broadcasting schemes also support concurrent updates to the same page at different sites. 相似文献
999.
In April 2001,the Govemment launched the West Kowllon Reclamation Concept Plan Competition to invite conceptral proposals for the development of a prominent 40-hectare waterfront site at the southern tip of the West Kowloon Reclamation into am integrated arts,cultural and entertainment district.The objective of the Competition is ,through the development,to enhance Hong Kong's positions as Asia's premiere centre of arts,culture and entertainment and create a new look for Victoria Harbour.The Competition attracted 161 entries,of which 71 were from Hong Kong and 90 were from elsewhere,covering some 30conntries.Adjudication of the Competition entries was made by a 10-member panel of Jury,chaired by Lord Rothschild. 相似文献
1000.
Hutchinson JP Zakaria P Bowie AR Macka M Avdalovic N Haddad PR 《Analytical chemistry》2005,77(2):407-416
A sulfonated methacrylate monolithic polymer has been synthesized inside fused-silica capillaries of diameters 50-533-microm i.d. and coated with 65-nm-diameter fully functionalized quaternary ammonium latex particles (AS18, Dionex Corp.) to form an anion-exchange stationary phase. This stationary phase was used for ion-exchange capillary electrochromatography of inorganic anions in a 75-microm-i.d. capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Seven inorganic anions (bromide, nitrate, iodide, iodate, bromate, thiocyanate, chromate) could be separated over a period of 90 s, and the elution order indicated that both ion exchange and electrophoresis contributed to the separation mechanism. Separation efficiencies of up to 1.66 x 10(5) plates m(-1) were achieved, and the monoliths were stable under pressures of up to 62 MPa. Another latex-coated monolith in a 250-microm-i.d. capillary was used for in-line preconcentration by coupling it to a separation capillary in which the EOF had been reversed using a coating of either a cationic polymer or cationic latex particles. Several capillary volumes of sample were loaded onto the preconcentration monolith, and the analytes (inorganic anions) were then eluted from the monolith with a transient isotachophoretic gradient before being separated by electrophoresis in the separation capillary. Linear calibration curves were obtained for aqueous mixtures of bromide, nitrite, nitrate, and iodide. Recoveries of all analytes except iodide were reduced significantly when the sample matrix contained high levels of chloride. The preconcentration method was applied to the determination of iodide in open ocean water and provided a limit of detection of 75 pM (9.5 ng/L) calculated at a signal-to-noise ratio of 3. The relative standard deviation for migration time and peak area for iodide were 1.1 and 2.7%, respectively (n = 6). Iodide was eluted as an efficient peak, yielding a separation efficiency of 5.13 x 10(7) plates m(-1). This focusing was reproducible for repeated analyses of seawater. 相似文献