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Kunkel Mark A.; Hector Mark A.; Góngora Coronado Elías; Castillo Vales Victor 《Canadian Metallurgical Quarterly》1989,36(3):322
Conducted a study of client expectations of psychological services in Yucatán, Mexico, under the sponsorship of a grant from the Organization of American States. The Expectations about Counseling–Brief form (EAC-B) questionnaire was translated and administered to 488 subjects across age, sex, and experience with psychological services. Subsequent analyses supported the reliability and robustness of the Spanish EAC-B, with factor structure similar to the EAC-B in English. Some relation was found among age, sex, prior counseling experience, and expectations about counseling. Implications of these data for future research and comparison with U.S. subjects are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
The TSIMMIS Approach to Mediation: Data Models and Languages 总被引:18,自引:2,他引:16
Hector Garcia-Molina Yannis Papakonstantinou Dallan Quass Anand Rajaraman Yehoshua Sagiv Jeffrey Ullman Vasilis Vassalos Jennifer Widom 《Journal of Intelligent Information Systems》1997,8(2):117-132
TSIMMIS—The Stanford-IBM Manager of Multiple InformationSources—is a system for integrating information. It offers a datamodel and a common query language that are designed to support thecombining of information from many different sources. It also offerstools for generating automatically the components that are needed tobuild systems for integrating information. In this paper we shalldiscuss the principal architectural features and their rationale. 相似文献
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Abstract. Outliers in time series seriously affect conventional parameter estimates. In this paper a robust recursive estimation procedure for the parameters of auto-regressve moving-average models with additive outliers is proposed. Using 'cleaned' residuals from an initial robust fit of an autoregression of high order as input, bounded influence regression is applied recursively. The proposal follows certain ideas of Hannan and Rissanen, who suggested a three-stage procedure for order and parameter estimation in a conventional setting.
A Monte Carlo study is performed to investigate the robustness properties of the proposed class of estimates and to compare them with various other suggestions, including least squares, M estimates, residual autocovariance and truncated residual autocovariance estimates. The results show that the recursive generalized M estimates compare favourably with them. Finally, possible modifications to master even vigourous situations are suggested. 相似文献
A Monte Carlo study is performed to investigate the robustness properties of the proposed class of estimates and to compare them with various other suggestions, including least squares, M estimates, residual autocovariance and truncated residual autocovariance estimates. The results show that the recursive generalized M estimates compare favourably with them. Finally, possible modifications to master even vigourous situations are suggested. 相似文献
6.
Fernando J. Beltrán 《臭氧:科学与工程》1997,19(1):13-38
Kinetics of competition between the ozone direct reaction with compounds in water, ozone-hydroperoxide ion reaction leading to free radicals in the O3/H2O2 process, and the photolysis of ozone in the O3/UV process are discussed in terms of diffusion and reaction times to establish conditions for these reactions to be competitive. Film theory and chemical kinetic concepts then are applied to estimate initial rates of ozone absorption and consumption, removal rates of compounds present in water, and the importance of the radical oxidation path versus direct ozone and/or photolysis reactions. 相似文献
7.
The homogeneous decomposition of ozone in the presence of a Co(II) catalyst has been investigated in aqueous solution. Under the conditions investigated (Co(II) concentration: 0.0 – 2.0?ppm, pH: 1.6- 8.4, O3 concentration: 5 10?5 – 2.0 104?M) the process can be assumed to follow pseudo first order kinetics with respect to ozone. Cobalt concentration dependency also obeys first order kinetics although it may be considered to reach a steady state concentration. pH exerts a positive influence on the decomposition rate from 1.6 to 7.1, the process leveling off at pH 8.4. An Arrhenius analysis of the temperature effect gave a moderate activation energy of the global reaction (E=10917?cal mol?1). A more detailed radical mechanism than a simple pseudo first order reaction can be postulated for simulation purposes. By numerical optimization of some unknown kinetic constants the influence of several operating variables can be adequately predicted. 相似文献
8.
Michael P. Balogh Camille Y. Jones J.F. Herbst Louis G. Hector Jr. Matthew Kundrat 《Journal of Alloys and Compounds》2006,420(1-2):326-336
Half-Heusler compounds of Sn-doped TiCoSb “TiCoSnxSb1−x (x = 0.0, 0.01, and 0.05)” were prepared and their thermoelectric properties were measured above room temperature. From the EDX analysis, all the samples have three phases: the TiCoSnxSb1−x, Co-rich, and Ti-rich phases. The values of the thermoelectric power increase with Sn doping, and a positive thermoelectric power is obtained in the sample of TiCoSn0.05Sb0.95. The thermal conductivity decreases both with increasing temperature and with Sn content. The maximum value of ZT for p-type material is 0.030 at 988 K in the sample of TiCoSn0.05Sb0.95. 相似文献
9.
K. V. Sudhakar J. C. Cisneros Hector Cervantes Cosme Gomez Pineda 《Journal of Materials Engineering and Performance》2006,15(1):117-121
The technology of materials removal is improved greatly by the introduction of advanced cutting tools like cubic boron nitride,
ceramics, polycrystalline diamond and the more recent whisker-reinforced materials. In this paper, the influence of cutting
temperature on machinability, mechanical properties, microstructure, and fracture morphology of Cu-2Be alloy using a polycrystalline
diamond cutter is investigated. The information on machining, microstructure, and fracture morphology of Cu-2Be alloy are
very useful to understand their fabrication characteristics and the basic mechanisms of its deformation and fracture. The
machinability (in terms of surface finish) of Cu-2Be alloy is evaluated as a function of cutting temperature, resulting from
wet and dry cutting. Machining is carried out on a Hardinge Cobra 42 CNC machine (Hardinge Inc., Elmira, NY), and the machining
parameters used—cutting speed, depth of cut, and feed rate—are kept constant during both wet and dry cutting. The machined
surface finish on Cu-2Be alloy is measured using a surface finish analyzer (Surftest 401, series 178) technique. The machined
specimens are examined for their strength and hardness properties using a standard Universal Testing Machine and Rockwell
hardness tester, respectively. Wet cutting (using coolants) produced a smooth surface finish when compared with dry cutting
of the Cu-2Be alloy. The machined specimens are examined for their microstructural features using a Nikon optical microscope.
The specimens are etched using a suitable etchant solution for revealing such microstructure constituents as grain size, phase
proportions, and the possible overheated areas (especially in dry cutting). The fractured surfaces from the tensile and impact
toughness tests are investigated for their fracture morphologies (dry and wet cutting) using a microprocessor-controlled scanning
electron microscope (Jeol Model JSM 5910 LV). A detailed analysis is also made to understand and interpret the basic fracture
mechanisms responsible for crack initiation and crack propagation. The Cu-2Be alloy showed relatively higher mechanical properties
in wet cutting in comparison to dry cutting operations. Fracture studies demonstrated intergranular and ductile fractures
as dominant modes of fracture mechanisms in Cu-2Be alloy. 相似文献
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