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131.
I. F. Shakhnov 《Automation and Remote Control》2004,65(10):1580-1596
Two models of ranking the interval-defined objects were described. They are based on the principles of domination in probability and utility. Proposed was a two-stage ranking procedure where the objects are first ranked according to the model of domination in probability and then this ranking is corrected using the model of domination in utility. 相似文献
132.
133.
134.
Visibility of collaboration on the Web 总被引:14,自引:3,他引:11
The emerging influence of new information and communication technologies (ICT) on collaboration in science and technology
has to be considered. In particular, the question of the extent to which collaboration in science and in technology is visible
on the Web needs examining. Thus the purpose of this study is to examine whether broadly similar results would occur if solely
Web data was used rather than all available bibliometric co-authorship data. For this purpose a new approach of Web visibility
indicators of collaboration is examined. The ensemble of COLLNET members is used to compare co-authorship patterns in traditional
bibliometric databases and the network visible on the Web. One of the general empirical results is a high percentage (78%)
of all bibliographic multi- authored publications become visible through search of engines in the Web. One of the special
studies has shown Web visibility of collaboration is dependent on the type of bibliographic multi-authored papers. The social
network analysis (SNA) is applied to comparisons between bibliographic and Web collaboration networks. Structure formation
processes in bibliographic and Web networks are studied. The research question posed is to which extent collaboration structures
visible in the Web change their shape in the same way as bibliographic collaboration networks over time. A number of special
types of changes in bibliographic and Web structures are explained.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
135.
A. F. Kurbatskii 《High Temperature》2004,42(1):79-87
The difference in the turbulent diffusion between the active (heat) and passive (mass) scalars in a thermally stably stratified medium is investigated. The axisymmetric problem is treated on the formation of a turbulent circulation flow above a heated disk and on the turbulent diffusion of a passive scalar (impurity) from a continuous surface source in a stably stratified medium. The results indicate that the thermal stratification causes appreciable differences in the coefficients of turbulent transfer between the active (heat) and passive (mass) scalars. This means that the assumption of the identity of the coefficient of turbulent diffusion of heat and mass, employed in conventional models of turbulence, produces significant errors in estimating the heat and mass transfer in a thermally stably stratified medium. 相似文献
136.
Thermal Transformations of an Aluminoborophosphate Binder 总被引:1,自引:0,他引:1
Thermal transformations of a commercial aluminoborophosphate binder are studied in a broad temperature range by optical microscopy, x-ray diffraction, IR spectroscopy, and thermal analysis. The introduction of B2O3 reduces the temperature of phosphate polycondensation, enhances the stability of cyclometaphosphates in a broad temperature range (180–1100°C), and reduces the stability of hydrogen phosphates. 相似文献
137.
This paper describes a research effort in the area of collision avoidance path planning for robotic manipulators. A robotic arm with known geometry is to perform a spatial manipulation in the presence of known obstacles in its workspace. The task is to generate a series of waypoints for its path to pass through which will guarantee a safe, collision-free trajectory from its predefined starting point to its predefined goal position.This is an important topic in the area of automated manufacturing. Automated factories are becoming increasingly important for the goals of greater manufacturing efficiency, better equipment utilization, and lower overall manufacturing costs. Robotic devices, including manipulator arms and assembly devices, are finding more uses in these factories.The approach is to discretize the robot's workspace into a transition network. The optimal path through this network, in terms of angular displacement of the manipulator's joints, is generated by dynamic programming. While this approach has been used previously, this paper adds the innovation of variable-node spacing, with the node density in various parts of the network reflecting the need for precise position control in each local area of the workspace. In this way, precise motion control is possible without an undue computational burden. 相似文献
138.
K. Fujii J. Fujimoto H. Hayashii R. Kajikawa Y. Masatani H. Ozaki A. Sugiyama R. Suzaki S. Suzuki T.Y. Tsukamoto T.F. Tsukamoto S. Uno S. Iwata 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,236(1):55-63
We constructed and tested a prototype gas sampling electromagnetic calorimeter of the Pb-proportional tube sandwich type. The calorimeter uses conductive plastic tubes and cathode pad readout with a tower structure which resulted in reasonable energy and spatial resolutions for electrons in the momentum range 0.5–4.0 GeV/c; /c). This paper describes the test and the performance studied under various conditions. 相似文献
139.
Based on the Ibl penetration model mass transfer equations for gas-evolving electrodes were derived and compared to the effect of forced convection. Experimental studies were conducted in a rectangular flow channel with the working electrode facing downward. The variables were linear bubble velocity, linear electrolyte velocity, nature of the gas and electrode position. Up to bubble velocities (Ux) of 2 and 6 cm s−1 for O2 and H2 gases respectively, the thickness of the Nernst diffusion layer (δav) was described well by the equation δav = [DdeL/(Ux)av]1/3. Intermediate slopes between − 1/3 and − 1 were observed for O2 bubble velocities between 2 and 6 cm s−1. A theoretical derivation suggests that in the absence of bubble coalescence, the mass transfer effect due to laminar flow induced by electrolytically evolved gas exceeds that due to forced external laminar flow for all practical channel designs. 相似文献
140.
Rate constants for the reversible deprotonation of acetylacetone were measured in carboxylate and amine buffers in water and in 50%, 90% and 95% Me2SO at 20°C. The Brønsted plot for the carboxylate ions is curved in the Me2SO—water mixtures, but straight in water. The curvature is in the direction predicted by the Reactivity—Selectivity Principle (RSP). However, the Brønsted plot for the reaction with primary amines is straight in all solvents. This suggests that the curvature observerd with the carboxylate ions is caused by loss of solvation of the base; this loss of solvation is ahead of bond formation in the transition state rather than being a manifestation of the RSP. (Note that all Brønsted plots are based on pKa values measured in the respective solvents.) The intrinsic rate constant (k0) for proton transfer increases with the addition of Me2SO, and more so with the carboxylate buffers than with the amines. This increase in k0 is attributed to delayed solvation of the developing enolate ion in the transition state; with the carboxylate buffers, an additional factor is the early loss of solvation of the base. The various solvation effects observed in this study can all be understood in the context of the Principle of Imperfect Synchronization (PIS). 相似文献