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81.
A study was made to determine a more comprehensive method of estimating the impact of an air pollutant on a region's economy. To do this, a Leontief input-output model of Clinton County, Pennsylvania was employed. Economic and related changes were simulated with the model by making appropriate changes and/or additions to the parameters of the model, i.e., the technical coefficients and elements of the external income input vector. In this specific application, the technical coefficients were represented by Direct Cost Response Functions in which the technical coefficient was a function of pollutant concentration. These functions were derived for the coefficients of all sectors whose expenditure pattern was affected by the pollutant. With these functions, it was possible to modify the base model to reflect the effect of different levels of pollutant concentration in the region. Economic impact studies yielding the direct and indirect changes in expenditures in all sectors of the model were then carried out showing the cost of air pollution damages to the region. 相似文献
82.
83.
A simple progressive exercise test was performed before and after operation on five subjects undergoing mitral valve replacement and on five subjects undergoing aortic valve replacement. The responses of heart rate and ventilation were related to work rate )kilopond metres/min). The patients were also assessed clinically by the New York Heart Association grading and radiologically before each exercise test. The clinical grading was shown to be a poor guide to observed exercise tolerance, as the improvement noted in symptoms was not matched by the objective measurement of working capacity. Only two patients had normal exercise tolerance after surgery, although six of the ten patients claimed that they had no exertional dyspnoea after operation. The changes in simple ventilatory function tests before and after operation were generally small. We suggest that measurements of exercise tolerance before and after operation should be an essential part of heart valve replacement surgery. 相似文献
84.
Techniques for computing the sensitivity of temperatures to changes in design variables needed for designing thermal protection systems are considered. It is shown that the choice of the most efficient technique depends on the ratio of number of temperature constraints to the number of design variabies, as well as on the thermal analysis method employed. The analysis is specialized to the case of a structure modelled by finite elements, and an example of an insulation panel is used demonstrate the techniques. 相似文献
85.
86.
Jim Gormally; Gary Sipps; Ralph Raphael; David Edwin; Douglas Varvil-Weld 《Canadian Metallurgical Quarterly》1981,49(2):300
Used the cognitive theories of A. Beck (see PA, Vol 56:8303) and A. Ellis (see PA, Vol 37:1437) to identify cognitive phenomena thought to be related to social anxiety. Their constructs, risk appraisal and irrational beliefs, were operationalized for the present study. Both discriminated between a clinical sample of 46 anxious men and a group of 18 competent daters (18–26 yrs). Together they accounted for 35% of the variance in social anxiety for a mixed sample of high, moderate, and low confident men. Ss were administered the Irrational Beliefs Test, Survey of Heterosexual Interactions, and Situational Expectancies Inventory. Results are discussed in terms of their clinical significance and implications for cognitive assessment of social anxiety. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
87.
A novel generalized approach to phase-shifting interferometry in which phase distribution in an interferogram is evaluated in the presence of nonsinusoidal waveforms and piezoactuator device miscalibration is proposed. The approach is based on the underlying rotational invariance of signal subspaces spanned by two temporally displaced data sets. The advantage of the proposed method lies in its ability to identify arbitrary phase-step values pixelwise from an interference signal buried in noise. The robustness of the proposed method is investigated by addition of white Gaussian noise during the simulations. 相似文献
88.
When vitrinite is catalytically dehydrogenated in the presence of phenanthridine as vehicle, the yield of hydrogen is not greatly influenced by the catalyst support or the concentration of metal on the support. The metal used has a large effect, palladium giving the highest yield of hydrogen. 相似文献
89.
Raphael Roth Thilo Glatzel Pascal Steiner Enrico Gnecco Alexis Baratoff Ernst Meyer 《Tribology Letters》2010,39(1):63-69
The occurrence of multiple jumps in 2D atomic-scale friction measurements is used to quantify the viscous damping accompanying
the stick–slip motion of a sharp tip in contact with a NaCl(001) surface. Multiple slips are observed without apparent wear
for normal forces between 13 and 91 nN. For scans parallel to [100] directions, the tip jumps between minima of the substrate
corrugation potential in a zigzag fashion. An algorithm is applied to determine histograms of lateral force jumps which characterize
multiple slips. The same algorithm is used to classify multiple slips occurring in calculated lateral force maps. Comparisons
between simulations and experiments indicate that the nanometer-sized contact is underdamped at intermediate loads (13–26 nN)
and becomes slightly overdamped at higher loads. The proposed procedure is a novel way to estimate the lateral contact damping
which plays an important role in the interpretation of measurements of the velocity and temperature dependence of friction,
of slip duration, and of the reduction of friction by applied perpendicular or parallel oscillations. 相似文献
90.
Due to the discreteness of electronic charges in a nanoscale system, capacitance is defined in terms of the total interaction energy of N-electrons confined in a dielectric sphere. Specifically, the distribution of N-electrons is obtained from minimization of the total Coulomb and polarization interaction energy and the formation energy, the work done on the system. Our discrete charge dielectric (DCD) model gives rise to an electrostatic capacitance agreeing with the N=1 and ∞ cases. For nanometer-size devices, the Schrödinger equation should be used; however, for size greater than 10 nm, the Poisson equation accounts for spatial symmetry properties resulting from the discrete nature of interacting electrons. Without metallic components, the equal potential landscape does not coincide with our spherical boundary except for the N=1 case. There is a special configuration associated with each N. Hence, the capacitance defined is monophasic, representing a single electrostatic phase. The most important application of this work may lie in optoelectronics and biological systems. 相似文献