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101.
Quantum energy coherences represent a thermodynamic resource, which can be exploited to extract energy from a thermal reservoir and deliver that energy as work. We argue that there exists a closely analogous classical thermodynamic resource, namely, energy-shell inhomogeneities in the phase space distribution of a system’s initial state. We compare the amount of work that can be obtained from quantum coherences with the amount that can be obtained from classical inhomogeneities, and find them to be equal in the semiclassical limit. We thus conclude that coherences do not provide a unique thermodynamic advantage of quantum systems over classical systems, in situations where a well-defined semiclassical correspondence exists. 相似文献
102.
The conventional method for separation of lead from a combined lead and barium sulphate precipitate by extraction with ammonium acetate has been critically studied. The results show that quantitative separation of lead is possible only when the molar concentration ratio of barium to lead is 4.2 or above, but at ratios below 4.2 the method fails because of the formation of a solid solution of lead and barium sulphates which is maximal at initial mole-ratio 0.42. The lead in the solid solution, however, forms a strong soluble complex with EDTA and can be quantitatively separated. Based on this, a gravimetric method has been worked out for determination of lead and barium in glass. 相似文献
103.
Dr. Tran Quang Hung Dr. Ferial Terki Dr. Souleymane Kamara Mourad Dehbaoui Prof. Salam Charar Brajalal Sinha Prof. CheolGi Kim Dr. Philippe Gandit Il'ya A. Gural'skiy Dr. Gabor Molnar Dr. Lionel Salmon Dr. Helena J. Shepherd Dr. Azzedine Bousseksou 《Angewandte Chemie (International ed. in English)》2013,52(4):1185-1188
104.
We derived new expressions for volume expansion ratio, thermal expansivity and higher order temperature derivative of volume
with the change in temperature. The relationships are developed on the basis of suggestion made by Wang and Reeber [12]. We
used a relationship demonstrating the temperature dependence of isothermal bulk modulus due to Srivastava et al. [13] to generate various other expressions. The model is applied on NaCl and KCl crystals. The superiority of the presented
formulations over other identical formulations is shown. A close agreement between theory and experiment reveals the validity
of the present work. 相似文献
105.
Synthesis of five-, six-, seven-, eight-, and nine-membered cyclic α-hydrazino acids from a common starting material ‘diethylmalonate’ with 26, 16, 34, 13.5, and 13.33% overall yields is described. Sequential allylation or homoallylation and electrophilic amination followed by cyclization gave the desired rings. The methyl esters of eight- and nine-membered rings were synthesized by RCM and the corresponding free acids were generated after hydrolysis in the presence of 1 M BBr3 solution in DCM. 相似文献
106.
K.C. Majumdar Randhir Kumar Sinha Santanu Chakravorty 《Journal of Physics and Chemistry of Solids》2009,70(8):1171-915
The miscibility of a rod-shaped (R) and a bent-shaped (BC) compound forming an induced B1 phase is reported. B1 phase is not present in both R and BC in the entire phase sequence. R exhibits partially bilayered smectic Ad phase with cholesteric and TGB while BC shows a B2 phase. It is interesting to show that the B2 phase is totally diminished in low composition (weight%) of BC, B1 phase is induced at lower temperature range (~90-135 °C). A dielectric study is also incorporated to confirm the induction of B1 phase in the binary mixture. 相似文献
107.
[Pd(-NaiR)(O,O)] [-NaiR = 1-alkyl-2-(naphthyl--azo)imidazoles; R = Me (a), Et (b), CH2Ph (c) and O,O = pyrocatecholato (cat) (3), 4-t-butylcatecholato (tbcat) (4), 3,5-di-t-butylcatecholato (dtbcat) (5), and tetracholorocatecholato (tccat) (6)] complexes were characterized by elemental analyses, i.r. and 1H-n.m.r. spectral data. Studies by cyclic voltammetry suggest the existence of two redox couples, positive saturated calomel electrode (s.c.e.) that are due to catecholes to semiquinone, and semiquinone to quinone oxidations, respectively; two couples at negative to s.c.e. are associated with azo reductions. The complexes exhibit ligand-to-ligand charge-transfer transition in the near-i.r. region. The band position is largely dependent upon the substituent on the catechole frame and exhibits a negative solvatochromic effect. The transition is qualitatively assigned to the HOMO (cat) LUMO (-NaiR) transition. 相似文献
108.
A new resin incorporating benzimidazolylazo group into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury(II), silver(I) and palladium(II) as a function of pH has been determined. The resin exhibits no affinity for alkali or alkaline earth metals. It is highly selective for Hg(II), Ag(I) and Pd(II). In column operation, it has been observed that Hg(II), Ag(I) and Pd(II) in trace quantities can be selectively separated from geological, medicinal and environmental samples. 相似文献
109.
Let A be a unital von Neumann algebra of operators on a complexseparable Hilbert space H0, and let {Tt, t 0} be a uniformlycontinuous quantum dynamical semigroup of completely positiveunital maps on A. The infinitesimal generator L of {Tt} is abounded linear operator on the Banach space A. For any Hilbertspace K, denote by B(K) the von Neumann algebra of all boundedoperators on K. Christensen and Evans [3] have shown that Lhas the form [formula] where is a representation of A in B(K) for some Hilbert spaceK, R: H0 K is a bounded operator satisfying the minimalitycondition that the set {(RX(X)R)u, uH0, XA} is totalin K, and K0 is a fixed element of A. The unitality of {Tt}implies that L(1) = 0, and consequently K0=iHR*R, whereH is a hermitian element of A. Thus (1.1) can be expressed as [formula] We say that the quadruple (K, , R, H) constitutes the set ofChristensenEvans (CE) parameters which determine theCE generator L of the semigroup {Tt}. It is quite possible thatanother set (K', ', R', H') of CE parameters may determine thesame generator L. In such a case, we say that these two setsof CE parameters are equivalent. In Section 2 we study thisequivalence relation in some detail. 1991 Mathematics SubjectClassification 81S25, 60J25. 相似文献
110.
Let H be a semibounded perturbation of the Laplacian H
0 in L
2(
d
). For an admissible function sufficient conditions are given for the completeness of the scattering system (H), (H
0). If is the exponential function and if e– H
is an integral operator we denote the kernel of the difference D
= e– H
– e– H
0 by D
(x, y), > 0. The singularly continuous spectrum of H is empty ifd dx
d dy |D(x,y)| (1 + |y|2)< for some > 1. This result is applied to potential perturbations and to perturbations by imposing Dirichlet boundary conditions. 相似文献