A variational perturbation approximation method in Tsallis non-extensive statistical physics

For the generalized statistical mechanics based on the Tsallis entropy, a variational perturbation approximation method with the principle of minimal sensitivity is developed by calculating the generalized free energy up to the third order in variational perturbation expansion. The approximation up to the first order amounts to a variational approach which covers the variational method developed by E.K. Lenzi, L.C. Malacarne, R.S. Mendes [Phys. Rev. Lett. 80 (1998) 218] and the approximations up to higher orders can systematically improve variational results. As an illustrated example, the generalized free energy for a classical harmonic oscillator (considered in the Lenzi's joint work) are calculated up to the third order, and the resultant approximations up to the first, second, and third orders are numerically compared with the exact result.     

Future Direction for a Diffusion Barrier in Future High-Density Volatile and Nonvolatile Memory Devices

This article reviews the current status of high-density capacitor for volatile memory devices. The dielectric properties for both the Ta₂O₅ film and the (Ba, Sr)TiO₃ (BST) dielectric materials using either the metal organic chemical vapor deposition (MOCVD) or the atomic layer deposition (ALD) are reviewed briefly. New challenges of dielectric material for the next generation, and serious problems emerged during integration to date using Ta₂O₅ and BST. The material characteristics of many electrode materials for the high dielectric materials are introduced. We present the basic properties and integration issued for MOCVD-ruthenium (Ru). The second part of this review summarized the failure mechanisms from barrier properties of previously reported diffusion barriers and emphasizes new design concepts of diffusion barrier for high-density memory devices. Finally, the future direction for a diffusion barrier to advance high-density memory capacitors is suggested.     

Cobalt Based Nanoparticles Embedded Reduced Graphene Oxide Aerogel for Hydrogen Evolution Electrocatalyst

Efficient water electrolysis catalyst is highly demanded for the production of hydrogen as a sustainable energy fuel. It is reported that cobalt derived nanoparticle (CoS₂, CoP, CoS|P) decorated reduced graphene oxide (rGO) composite aerogel catalysts for highly active and reliable hydrogen evolution reaction electrocatalysts. 7 nm level cobalt derived nanoparticles are synthesized over graphene aerogel surfaces with excellent surface coverage and maximal expose of active sites. CoS|P/rGO hybrid aerogel composites show an excellent catalytic activity with overpotential of ≈169 mV at a current density of ≈10 mA cm^?2. Accordingly, efficient charge transfer is attained with Tafel slope of ≈52 mV dec^?1 and a charge transfer resistance (R_ct) of ≈12 Ω. This work suggests a viable route toward ultrasmall, uniform nanoparticles decorated graphene surfaces with well‐controlled chemical compositions, which can be generally useful for various applications commonly requiring large exposure of active surface area as well as robust interparticle charger transfer.     

Lithography potentials of UV-nanoimprint

In the past decade nanoimprint has been developed to a serious alternative for next generation lithography (NGL). In this work, the most recent developments of UV-nanoimprint Lithography (UV-NIL) with special emphasis to the work accomplished at AMO and the IHT-RWTH Aachen are reviewed and functional applications demonstrated. Further the potentials of various UV-NIL concepts are evaluated and possible interests in certain application areas are discussed.     

13C NMR study of alcohols complexed with nitroxide radical

The contact shifts of carbon nuclei in 8 alcohols complexed with 2,2,6,6-tetramethylpiperidine nitroxide radical were determined from the ¹³C NMR spectra and explained by hydrogen bonding and collision interactions.     

A novel synthesis of 5-functionalized oxazolidin-2-ones from enantiomerically pure 2-substituted N-[(R)-(+)-alpha-methylbenzyl]aziridines

5-Funtionalized enantiomerically pure oxazolidin-2-ones were prepared in one pot from commercially available chiral aziridines bearing an electron-withdrawing group at C-2 with retention of the configuration in high yields by regioselective aziridine ring-opening followed by intramolecular cyclization.     

Structure of liquid water with ST2 model potentials in the temperature interval 273–373 K

Ufa Aviation Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 4, pp. 69–73, July–August 1990.     

Separation of D‐psicose and D‐fructose using simulated moving bed chromatography

Simulated moving bed (SMB) processes have been widely used in the sugar industries with ion‐exchange resin as a stationary phase. D ‐Psicose, a rare monosaccharide known as a valuable pharmaceutical substrate, was synthesized by the enzymatic conversion from D ‐fructose. The SMB process was adopted to separate D ‐psicose from D ‐fructose. Before the SMB experiment, the reaction mixture including D ‐psicose and D ‐fructose was treated by a deashing process to remove contaminants, such as buffers, proteins, and other organic materials. Four columns packed with Dowex 50WX4‐Ca²⁺ (200–400 mesh) ion‐exchange resins were used in the four‐zone SMB. Single‐step frontal analysis was performed to estimate the isotherm parameters of each monosaccharide. The operating conditions of the SMB process were determined based on the Equilibrium Theory. According to the simulation of the SMB process, the purity and yield of extract product (D ‐psicose) achieved were 99.04 and 97.46%, respectively and those of raffinate product (D ‐fructose) were 99.06 and 99.53%, respectively. Under the optimized operating condition, complete separation (extract purity = 99.36%, raffinate purity = 99.67%) was achieved experimentally.     

Sulfone coupling and double-elimination strategy for carotenoid synthesis

[Reaction: see text]. A highly efficient synthetic method of carotenoid compounds has been developed on the basis of the sulfone coupling and double-elimination strategy. This method highlighted the sulfone-mediated coupling with the novel C(10) dialdehyde, 2,7-dimethyl-4-octenedial, which was easily prepared and efficiently utilized in the synthesis of the conjugated polyene chains.     

Importance of supersuperexchange interactions in determining the dimensionality of magnetic properties. Determination of strongly interacting spin exchange paths in A(2)Cu(PO(4))(2) (A = Ba, Sr), ACuP(2)O(7) (Ba, Ca, Sr, Pb), CaCuGe(2)O(6), and Cu(2)UO(2)(PO(4))(2) on the basis of qualitative spin dimer analysis

The patterns of the Cu(2+) ion arrangements in the magnetic oxides A(2)Cu(PO(4))(2) (A = Ba, Sr), ACuP(2)O(7) (Ba, Ca, Sr, Pb), CaCuGe(2)O(6), and Cu(2)UO(2)(PO(4))(2) are quite different from the patterns of the strongly interacting spin exchange paths deduced from their magnetic properties. This apparently puzzling observation was explained by evaluating the strengths of the Cu-O-Cu superexchange and Cu-O...O-Cu supersuperexchange interactions of these oxides on the basis of qualitative spin dimer analysis. Supersuperexchange interactions are found to be crucial in determining the dimensionality of magnetic properties of these magnetic oxides.