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41.
A modified CIECAM02 colour appearance model, named CIECAM02‐m2, is proposed to enable CIECAM02 to predict the simultaneous contrast effect. The structure of the CIECAM02‐m2 is a development from CIECAM02, and contains two different procedures for modifying the reference white; one is for lightness and the other is for hue. The model was tested using a data set accumulated in this study and the LUTCHI data. The CV values for three colour attributes between predictions and experimental data were used to evaluate the accuracy of the model. The low CV values obtained show the performance of the CIECAM02‐m2 model to predict the simultaneous contrast effect satisfactorily. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 121 – 129, 2007  相似文献   
42.
Nicosia     
Roger Zetter 《Cities》1985,2(1):24-33
This profile of Nicosia, the capital of Cyprus, focuses on a crucial aspect of its historical growth and emerging planning responses: the issue of urban land. In Nicosia, as elsewhere, an understanding of land markets and the actors and agencies involved in development processes is indispensable for the management of urban change and the effective implementation of planning strategies for future growth. The provision of land which is affordable and available to urban dwellers has become a central issue, especially in the developing world. Accordingly, the relationship between planning policies and land issues, so long ignored by many planning systems, has become the new focus of current practice and research.  相似文献   
43.
Two experiments, with 80 undergraduates, replicated and extended research by R. T. Croyle and J. Cooper (see record 1984-11595-001) indicating that cognitive dissonance involves physiological arousal. In Exp I, Ss wrote counterattitudinal essays under conditions of high or low choice and, to assess arousal effects owing to effort, with or without a list of arguments provided by the experimenter. In high-choice conditions only and regardless of effort, Ss showed both arousal (heightened galvanic skin response) and attitude change. Arousal, however, did not decline following attitude change. The more effortful task (no arguments provided) produced increased arousal but not greater attitude change. In Exp II, the opportunity to change one's attitude following a freely chosen counterattitudinal essay was manipulated. As in Exp I, arousal increased following the essay but did not decline following a postessay attitude change opportunity. When Ss were not given an attitude change opportunity, however, arousal did decline. It is suggested that if dissonance is a drive state, drive reduction typically may be accomplished through gradual cognitive change or forgetting. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
44.
A model for the compressive buckling of extended chain polymers   总被引:1,自引:0,他引:1  
A model for the compressive buckling of an extended polymer chain is presented. The application of classical elastic instability analysis to an idealized polymer chain reveals that the bending rigidity and critical buckling loads for a chain are proportional to the force constants for valence bond angle bending and torsion. Highly oriented polymer fibres are treated as a collection of elastic chains that interact laterally. The critical stresses to buckle this collection of chains are calculated following a procedure developed to predict the compressive strengths of fibre-reinforced composites. This buckling stress is predicted to be equal to the shear modulus of the fibres and is the limiting value of compressive strength. Comparison of experimental and predicted values shows that the theory overestimates the compressive strength, but that there is a correlation of shear modulus with axial compressive strength. Consideration of flaws in both the theory and the material indicate that the compressive strength should be proportional to either the shear modulus or shear strength of the fibres.Nomenclature P axial compressive load (force) - P cr critical buckling load (force) - M,M i bending moments - l length of a link - p number of links - k elastic hinge constant - , i angular rotation of hinges - L overall chain or column length - v,v i lateral deflection of buckled chain or column - x, y, z Cartesian coordinate axes - E Young's modulus of isotropic column - I moment of inertia - a ij matrix coefficients - A p coefficient for exact buckling loads of chains - T energy change due to work of external load on buckled column or chain - U 1 bending strain energy change of buckled column or chain - U 2, U 2 e , U 2 s strain energy changes in elastic foundation, where e refers to extension mode buckling and s refers to shear mode buckling - E t transverse modulus - G longitudinal shear modulus - b dimension associated with chain packing - A cross-sectional area per chain (=b 2) - f(x) curve fitted to shape of buckled chain - m,n,r integers - a n coefficients of trigonometric series - y normal strain iny-direction - y normal stress iny-direction - xy shear strain inxy plane - xy shear stress inxy plane - u x displacement inx-direction - u y displacement iny-direction - V volume  相似文献   
45.
A static magnetic field having the strength of B=0.6 T has been used as an additional process parameter in order to suppress the establishment of pores while dispersing TiC particles in surface layers of aluminium alloys using a laser. The migration of hydrogen towards regions of high temperatures within the melting pool can lead to the creation of gas bubbles, therefore yielding pores after resolidification in the processed layer. This mechanism (known for instance in welding technologies of aluminium) could be suppressed by Lorentz-forces induced by an externally applied magnetic field. It could be shown experimentally that magnetic fields could assist laser surface treatment processes beneficially if higher beam powers were coupled in. This may be interesting if, for instance, thicker dispersed layers should be achieved.  相似文献   
46.
A general survey of fluorinated phosphazene polymers starting from their synthesis in 1965 to recent times is presented. Various types of fluorinated phosphazenes are described depending on the way fluorine atoms are connected to the polyphosphazene skeleton. The characterization, properties and practical utilization of these compounds in different domains are critically discussed.  相似文献   
47.
Atmospheric degradation of volatile organic compounds   总被引:19,自引:0,他引:19  
Atkinson R  Arey J 《Chemical reviews》2003,103(12):4605-4638
  相似文献   
48.
Robot manufacturers will be required to demonstrate objectively that all reasonably foreseeable hazards have been identified in any robotic product design that is to be marketed commercially. This is problematic for autonomous mobile robots because conventional methods, which have been developed for automatic systems do not assist safety analysts in identifying non-mission interactions with environmental features that are not directly associated with the robot’s design mission, and which may comprise the majority of the required tasks of autonomous robots. In this paper we develop a new variant of preliminary hazard analysis that is explicitly aimed at identifying non-mission interactions by means of new sets of guidewords not normally found in existing variants. We develop the required features of the method and describe its application to several small trials conducted at Bristol Robotics Laboratory in the 2011–2012 period.  相似文献   
49.
An investigation was made of the magnitude and mechanism of shear degradation of a narrow distribution, high molecular weight (Mw = 670,000) polystyrene. An Instron rheometer was used to perform the extrusion at temperatures from 164° to 250°C. The change in molecular weight distribution was studied by gel permeation chromatography. The maximum shear stress employed was 5.83 kg/cm2. It was found that degradation could be induced at high stress at temperatures of 50°C lower than degradation of polystyrene would occur exclusively due to thermal forces. An activation energy for the degradation, calculated at constant shear rate, was +20.2 kcal/mole. The direction and magnitude of this value are consistent with degradation induced through a mechanical reduced activation for thermal degradation.  相似文献   
50.
In this paper we discuss aspects of the concept described by Somorjai as the flexible surface, and whether some surfaces can be considered to be inflexible, or rigid. We present STM results which appear to manifest both types of behaviour for surfaces, depending on their oxidation state. Copper metal surfaces can be classed as flexible, showing facile reconstruction in the presence of oxygen, whereas an oxidised Pd(110) surface shows no apparent diffusivity, even at 500 K. We go on to show data for a bulk oxide which indicates that sub-stoichiometry in the sample induces an element of flexibility in the surface, especially during reaction with oxygen. Finally, this is related to the direct observation of spillover on model catalysts of Pd nanoparticles supported on TiO2. It must be recognised that flexibility relates to surface diffusivity and hence length- and time-scales. Surfaces which appear inflexible at short times may be flexible at long times. In relation to catalysis then, surface flexibility depends on the relationship between the time-scale of diffusive events on the surface and the catalytic turnover number.  相似文献   
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