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991.
The importance of surface contamination as a potential source of exposure to hazardous materials is discussed. Data from the literature concerning the resuspension of indoor surface contamination are presented. Reported procedures for quantitating surface contamination are compared. It is suggested that, despite its limitations, surface contamination monitoring may be useful in estimating potential risks from hazardous materials. 相似文献
992.
We report the fabrication and testing of 4-, 7-and 19-fibre fused biconical taper transmissive star couplers for use with single multimode fibres. Overall insertion losses on six couplers range from ?1.3 dB to ?2.6 dB. Losses are nearly independent of N, the number of fibres, but dispersion of the powers in the output fibres increases significantly with N. 相似文献
993.
Daniel F. Varnell Eric J. Moskala Paul C. Painter Michael M. Coleman 《Polymer Engineering and Science》1983,23(12):658-662
FT-IR spectroscopic studies have been performed in an attempt to elucidate the nature of the specific interactions occurring in miscible poly(?-caprolactone) (PCL)-poly (vinyl chloride) (PVC) blends. Studies of low molecular weight analogues, polymer/solvent mixtures and blends of PCL and α-deuterated PVC are presented. The results strongly suggest that a hydrogen bonding type of interaction between the carbonyl bond of PCL and the α-hydrogen of PVC exists in compatible PCL-PVC blends. 相似文献
994.
Affect, generalization, and the perception of risk. 总被引:1,自引:0,他引:1
Investigated the role of affect in judgments of risk in 4 experiments. 557 Ss were recruited on college campuses and read paragraphs modeled after newspaper reports that described fatal or nonfatal accidents or (Exp III) positive events. Ss were later asked to estimate the chances of specific fatal or nonfatal accidents happening to them and/or to the population in general. Experimental manipulations of affect induced by report of a tragic event produced a pervasive increase in Ss' estimates of the frequency of many risks and other undesirable events. Contrary to expectation, the effect was independent of the similarity between the report and the estimated risk: An account of a fatal stabbing did not increase the frequency estimate of homicide more than the estimates of unrelated risks such as natural hazards. An account of a happy event that created positive affect produced a comparable global decrease in judged frequency of risks. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
995.
Eric Sheppard 《Papers in Regional Science》1983,52(1):175-186
Two sources of urban growth differentials that intimately stem from the interdependencies between cities are unequal gains from interurban commodity trade, and spatial differentials in corporate ownership. Each of these phenomena has the potential of redistributing the physical and monetary surplus accruing from production unevenly between cities. This study develops a theoretical model to examine these problems, taking as its starting point a Marxian model of reproduction, prices, profits and wages. An interurban model of production and trade for a capitalist society with production restricted to small enterprises is constructed. Some system-wide and local accounting relationships are formulated that reveal the flows of profits, investment income, and surplus value between cities as a result of the postulated trading patterns. These are used to demonstrate the difference between profit and surplus value movements among locations, and to mathematically formulate the classical problem of unequal exchange of labour values relative to monetary values. 相似文献
996.
Gate-level logic simulation takes up more CPU time as system complexity increases. A special-purpose system which can cut verification time by several orders of magnitude is described. The Yorktown Simulation Engine (YSE) is a highly parallel programmable machine which can simulate up to 1 M gates at a speed of over 2000M gate simulations per second. It is estimated that the IBM 3081 processor could have been simulated at over 1 000 instructions per second on YSE. Gate-level logic simulation is reviewed and the architecture and hardware implementation of the YSE is described. The software architecture, including compiler, linker and register-level language translator, Ysetran, architecture, are detailed. 相似文献
997.
998.
Soap manufacture from fatty acids is a well established precess with some advantages over continuous saponification of neutral fats. These include:
- Ability to use cheaper fats.
- Easier glycerol recovery.
- Better control over by-products.
- Versatility-fatty acids can be used to make other derivatives than soaps.
999.
Effect of electrolyte concentration on the viscosity and voltammetry of supercritical solutions 总被引:1,自引:0,他引:1
The viscosity of a supercritical electrolyte solution is measured for the first time using a modified quartz crystal microbalance, and it is shown that ionic solvation leads to a significant structuring of the solvent and an appreciable increase in solution viscosity. Voltammetric investigations in the electrolyte solutions are used to confirm the magnitude of the viscosity changes, and these account for the appreciably lower than expected peak currents. 相似文献
1000.
A uniform-field design approach can improve the performance of microanalytical, chip-based devices for a number of applications, including separations and sample preparation. The faceted prism paradigm allows the design of microfluidic devices possessing spatially uniform fields in electrokinetically driven flows. We present the first quantitative study of the velocity fields obtained using faceted interfaces between deep and shallow channel sections. Electrokinetic flows were generated in a series of wet-etch fabricated microfluidic channels. The resulting velocity fields were analyzed by particle image velocimetry and compared with simulations of the two-dimensional Laplace equation using both the designed channel geometry and the as-fabricated channel geometry. This analysis found localized differences between the designed and observed flow fields that were directly attributable to the limitations of isotropic substrate etching. Simulations using the as-fabricated channel geometry reproduced the experimental electrokinetic velocity field, quantitatively accounting for speed field variations due to the limits of the fabrication method. The electrokinetic speed fields were also compared to corresponding pressure-driven speed fields. 相似文献