Preparation of Nanostructured Li2MnO3 Cathode Materials by Single-Step Hydrothermal Method

Nanosized (10~50 nm) cathode material Li2MnO3 was prepared for with MnSO4·H2O，KMnO4 and Li- OH aqueous solution as the precursor via single-step hydrothermal reaction by controlling the reaction time, proportion of processor, and the reagent concentration. The prepared materials were well crystallized and exhibited a monoclinic Li2MnO3 structure with a space group of C2/m phase. The electrochemical performance of the material was tested at current density of 60 mAg-1 (1/4 C) between 4.3V and 2.0 V at room temperature, showing good electrochemical properties with the initial discharge capacity of 243 mAh·g-1, because it was more exposed to the electrolyte due to its nanostructure. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

Surfactant Assisted Synthesis of LiFePO4 Nanostructures via Hydrothermal Processing

LiFePO4 is a potential cathode candidate for of secondary lithium batteries due to its low-cost, out-standing thermal stability and innocuity. In this paper, pure LiFePO4 obtained by hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as surfactant. LiFePO4 particles produced without any surfactant showed typical morphologies of perfect octahedral with size of ~1μm. For products prepared with addition CTAB, the amount of surfactant controlled the growth of LiFePO4 crystals, with which dif-ferent morphologies of plate, grains and flower-like structures were produced. Plate products displayed a capacity of 145.70 mAh•g-1 at 0.1C, which was superior to others. The results indicated the electrochemical performance depends crucially on the size and structure of active materials. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

The flavor-changing bottom-strange quark production in the littlest Higgs model with T parity at the ILC

In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the special flavor structures and some new flavor-changing (FC) couplings which could greatly enhance the production rates of the FC processes. We in this paper study some bottom and anti-strange production processes in the LHT model at the International Linear Collider (ILC), i.e., $e^+e^-\rightarrow b\bar{s}$ and $\gamma\gamma\rightarrow b\bar{s}$. The results show that the production rates of these processes are sizeable for the favorable values of the parameters. Therefore, it is quite possible to test the LHT model or make some constrains on the relevant parameters of the LHT through the detection of these processes at the ILC.Comment: 12 pages, 8 figure

Structure and Electrochemical Performance of Li[Li0.2Co0.4Mn0.4]O2 Cathode Material for Lithium Ion Battery by Co-precipitation Method

The nano-structured Li[Li0.2Co0.4Mn0.4]O2 cathode material is synthesized by a co-precipitation method. X-ray diffraction shows that the synthesized material has a hexagonal α-NaFeO2 type structure with a space group R-3m. Scanning electron microscopy and transmission electron microscopy images show the homogeneous distribution with 100-200 nm. X-ray photoelectron spectroscopy results indicate that the oxi-dation states of Co and Mn in Li[Li0.2Co0.4Mn0.4]O2 are present in trivalence and tetravalence, respectively. The charge-discharge curves and cycling performance are analyzed in detail. The initial charge and dis-charge capacities are respectively 236.5 mAh g-1 and 140.3 mAh g-1 at the current density of 100 mA g-1 in the voltage range of 2.0-4.6 V. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

Accelerated Particle Swarm Optimization and Support Vector Machine for Business Optimization and Applications

Business optimization is becoming increasingly important because all business activities aim to maximize the profit and performance of products and services, under limited resources and appropriate constraints. Recent developments in support vector machine and metaheuristics show many advantages of these techniques. In particular, particle swarm optimization is now widely used in solving tough optimization problems. In this paper, we use a combination of a recently developed Accelerated PSO and a nonlinear support vector machine to form a framework for solving business optimization problems. We first apply the proposed APSO-SVM to production optimization, and then use it for income prediction and project scheduling. We also carry out some parametric studies and discuss the advantages of the proposed metaheuristic SVM.Comment: 12 page

The rare decays B --> K(*) anti-K(*) and R-parity violating supersymmetry

We study the branching ratios, the direct CP asymmetries in $B\to K^{(*)}\bar{K}^{(*)}$ decays and the polarization fractions of $B\to K^{*}\bar{K}^{*}$ decays by employing the QCD factorization in the minimal supersymmetric standard model with R-parity violation. We derive the new upper bounds on the relevant R-parity violating couplings from the latest experimental data of $B\to K^{(*)}\bar{K}^{(*)}$, and some of these constraints are stronger than the existing bounds. Using the constrained parameter spaces, we predict the R-parity violating effects on the other quantities in $B\to K^{(*)}\bar{K}^{(*)}$ decays which have not been measured yet. We find that the R-parity violating effects on the branching ratios and the direct $CP$ asymmetries could be large, nevertheless their effects on the longitudinal polarizations of $B\to K^{*}\bar{K}^{*}$ decays are small. Near future experiments can test these predictions and shrink the parameter spaces.Comment: 31 pages with 10 figure

The productions of the top-pions and top-Higgs associated with the charm quark at the hadron colliders

In the topcolor-assistant technicolor (TC2) model, the typical physical particles, top-pions and top-Higgs, are predicted and the existence of these particles could be regarded as the robust evidence of the model. These particles are accessible at the Tevatron and LHC, and furthermore the flavor-changing(FC) feature of the TC2 model can provide us a unique chance to probe them. In this paper, we study some interesting FC production processes of top-pions and top-Higgs at the Tevatron and LHC, i.e., $c\Pi_{t}^{-}$ and $c\Pi_{t}^{0}(h_{t}^{0})$ productions. We find that the light charged top-pions are not favorable by the Tevatron experiments and the Tevatron has a little capability to probe neutral top-pion and top-Higgs via these FC production processes. At the LHC, however, the cross section can reach the level of $10\sim 100$ pb for $c\Pi_t^-$ production and $10\sim 100$ fb for $c\Pi_t^0(h_t^0)$ production. So one can expect that enough signals could be produced at the LHC experiments. Furthermore, the SM background should be clean due to the FC feature of the processes and the FC decay modes $\Pi_t^-\to b\bar{c}, \Pi_t^0(h_t^0)\to t\bar{c}$ can provide us the typical signal to detect the top-pions and top-Higgs. Therefore, it is hopeful to find the signal of top-pions and top-Higgs with the running of the LHC via these FC processes.Comment: 12 pages, 6 figure

Spontaneous Creation of Inflationary Universes and the Cosmic Landscape

We study some gravitational instanton solutions that offer a natural realization of the spontaneous creation of inflationary universes in the brane world context in string theory. Decoherence due to couplings of higher (perturbative) modes of the metric as well as matter fields modifies the Hartle-Hawking wavefunction for de Sitter space. Generalizing this new wavefunction to be used in string theory, we propose a principle in string theory that hopefully will lead us to the particular vacuum we live in, thus avoiding the anthropic principle. As an illustration of this idea, we give a phenomenological analysis of the probability of quantum tunneling to various stringy vacua. We find that the preferred tunneling is to an inflationary universe (like our early universe), not to a universe with a very small cosmological constant (i.e., like today's universe) and not to a 10-dimensional uncompactified de Sitter universe. Such preferred solutions are interesting as they offer a cosmological mechanism for the stabilization of extra dimensions during the inflationary epoch.Comment: 52 pages, 7 figures, 1 table. Added discussion on supercritical string vacua, added reference

Non-paraxial Split-step Finite-difference Method for Beam Propagation

A method based on symmetrized splitting of the propagation operator in the finite difference scheme for non-paraxial beam propagation is presented. The formulation allows the solution of the second order scalar wave equation without having to make the slowly varying envelope and one-way propagation approximations. The method is highly accurate and numerically efficient. Unlike most Padé approximant based methods, it is non-iterative in nature and requires less computation. The method can be used for bi-directional propagation as well

Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity $n_c$ and semileptonic branching ratio $B_{SL}$. Within the considered parameter space, the enhancement to the ratio $BR(b \to s g)$ due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio $BR(b \to no charm)$ can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of $B_{SL}$ and $n_c$ can be decreased simultaneously in the model III. The central value of $B_{SL}$ will be lowered slightly by about 0.003, but the ratio $n_c$ can be reduced significantly from the theoretical prediction of $n_c= 1.28 \pm 0.05$ in the SM to $n_c= 1.23 \pm 0.05$, $1.18 \pm 0.05$ for $m_{H^+}=200, 100$ GeV, respectively. We find that the predicted $n_c$ and the measured $n_c$ now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.