864 resultados para WEAK ELECTROLYTES
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"B-286196"--P. 3.
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"NsG 24-59. Sponsored by National Aeronautics and Space Administration."
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Adsorption of p-cresol, nitrobenzene and p-nitrophenol on treated and untreated carbons is investigated systematically. The effects of carbon surface chemistry and solution pH are studied and discussed. All adsorption experiments were carried out in pH-controlled solutions to examine the adsorption properties of the adsorption systems where the solutes are in molecular as well as ionic forms. Using the homogeneous Langmuir equation, the single solute parameters are determined. These parameters are then used to predict the binary solute adsorption isotherms and gain further insights into the adsorption process. (C) 2002 Elsevier Science Ltd. All rights reserved.
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The concept of biperfect (noncocommutative) weak Hopf algebras is introduced and their properties are discussed. A new type of quasi-bicrossed products is constructed by means of weak Hopf skew-pairs of the weak Hopf algebras which are generalizations of the Hopf pairs introduced by Takeuchi. As a special case, the quantum double of a finite dimensional biperfect (noncocommutative) weak Hopf algebra is built. Examples of quantum doubles from a Clifford monoid as well as a noncommutative and noncocommutative weak Hopf algebra are given, generalizing quantum doubles from a group and a noncommutative and noncocommutative Hopf algebra, respectively. Moreover, some characterizations of quantum doubles of finite dimensional biperfect weak Hopf algebras are obtained. (C) 2004 American Institute of Physics.
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For a parameter, we consider the modified relaxed energy of the liquid crystal system. Each minimizer of the modified relaxed energy is a weak solution to the liquid crystal equilibrium system. We prove the partial regularity of minimizers of the modified relaxed energy. We also prove the existence of infinitely many weak solutions for the special boundary value x.
Review of Edwin Black: War against the weak: Eugenics and America's campaign to create a master race
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The adsorption of p-nitrophenol in one untreated activated carbon (F100) and three treated activated carbons (H-2, H2SO4 and Urea treated F100) was carried out at undissociated and dissociated conditions. To characterize the carbon, N-2 and CO2 adsorption were used. X-ray Photoelectron Spectroscopy (XPS) was used to analyze the surface of the activated carbon. The experimental isotherms are fitted via the Langmuir homogenous model and Langmuir binary model. Variation of the model parameters with the solution pH is studied. Both Q(max) and the adsorption affinity coefficient (K-1) were dependent on the PZC of the carbons and solution pH. The Effect of pH must be considered due to its combined effects on the carbon surface and on the solute molecules. Adsorption of p-nitrophenol at higher pH was found to be dependent on the concentration of the anionic form of the solute.
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We experimentally determine weak values for a single photon's polarization, obtained via a weak measurement that employs a two-photon entangling operation, and postselection. The weak values cannot be explained by a semiclassical wave theory, due to the two-photon entanglement. We observe the variation in the size of the weak value with measurement strength, obtaining an average measurement of the S-1 Stokes parameter more than an order of magnitude outside of the operator's spectrum for the smallest measurement strengths.
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Doped ceria (CeO2) compounds are fluorite-type oxides that show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, considerable interest has been shown in application of these materials for low (500 degrees-650 degrees C) temperature operation of solid oxide fuel cells (SOFCs). To improve the conductivity in dysprosium (Dy) doped CeO2, nano-size round shape particles were prepared using a coprecipitation method. The dense sintered bodies with small grain sizes (< 300 nm) were fabricated using a combined process of spark plasma sintering (SPS) and conventional sintering (CS). Dy-doped CeO2 sintered body with large grains (1.1 mu m) had large micro-domains. The conductivity in the sintered body was low (-3.2 S/cm at 500 degrees C). On the other hand, the conductivity in the specimens obtained by the combined process was considerably improved. The micro-domain size in the grain was minimized using the present process. It is concluded that the enhancement of conductivity in dense specimens produced by the combined process (SPS+CS) is attributable to the microstructural changes within the grains.
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The process of adsorption of two dissociating and two non-dissociating aromatic compounds from dilute aqueous solutions on an untreated commercially available activated carbon (B.D.H.) was investigated systematically. All adsorption experiments were carried out in pH controlled aqueous solutions. The experimental isotherms were fitted into four different models (Langmuir homogenous Models, Langmuir binary Model, Langmuir-Freundlich single model and Langmuir-Freundlich double model). Variation of the model parameters with the solution pH was studied and used to gain further insight into the adsorption process. The relationship between the model parameters and the solution pH and pK(a) was used to predict the adsorption capacity in molecular and ionic form of solutes in other solution. A relationship was sought to predict the effect of pH on the adsorption systems and for estimating the maximum adsorption capacity of carbon at any pH where the solute is ionized reasonably well. N-2 and CO2 adsorption were used to characterize the carbon. X-ray Photoelectron Spectroscopy (XPS) measurement was used for surface elemental analysis of the activated carbon.
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Recently, there have been several suggestions that weak Kerr nonlinearity can be used for generation of macroscopic superpositions and entanglement and for linear optics quantum computation. However, it is not immediately clear that this approach can overcome decoherence effects. Our numerical study shows that nonlinearity of weak strength could be useful for macroscopic entanglement generation and quantum gate operations in the presence of decoherence. We suggest specific values for real experiments based on our analysis. Our discussion shows that the generation of macroscopic entanglement using this approach is within the reach of current technology.
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Recent advances in biomedical science indicate that it may eventually be possible to intervene in the biological process of human ageing. This paper overviews the current state of the science of lifespan extension and promising future directions. It is uncertain whether 'strong' lifespan extension - the extension of human life beyond the maximum 122 years so far observed - will become a reality. It is more likely that cumulative effects of numerous scientific and biomedical advances in the treatment of common disease will produce 'weak' lifespan extension - the extension of average life expectancy. The practical application of molecular, genetic and nanomaterials research may also lead to advances in life expectancy. It is not too early to begin to consider the policy implications of either form of lifespan extension.
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We investigate decoherence effects in the recently suggested quantum-computation scheme using weak nonlinearities, strong probe coherent fields, detection, and feedforward methods. It is shown that in the weak-nonlinearity-based quantum gates, decoherence in nonlinear media can be made arbitrarily small simply by using arbitrarily strong probe fields, if photon-number-resolving detection is used. On the contrary, we find that homodyne detection with feedforward is not appropriate for this scheme because in this case decoherence rapidly increases as the probe field gets larger.