We propose the schemes of quantum secure direct communication (QSDC) based on secret transmitting order of particles. In these protocols, the secret transmitting order of particles ensures the security of communication, and no secret messages are leaked even if the communication is interrupted for security. This strategy of security for communication is also generalized to quantum dialogue. It not only ensures the unconditional security but also improves the efficiency of communication.

Recently, two-dimensional (2D) layered transition metal dichalcogenides (LTMDs) have attracted great scientific interest for ion battery applications. Because of its remarkable metallic property, vanadium disulfide (VS 2 ) as a typical family member of LTMDs, can be an alternative anode material for ion battery applications. In this paper, we systematically investigate the adsorption energy and diffusion coefficient of the lithium and sodium ions in monolayer and bulk VS 2 for lithium and sodium ion batteries by a density functional theory method. Our calculations show that the VS 2 capacity can reach up to 466 mA h g À1 . It exhibits a low output voltage of 0.72 and 0.48 V for lithium and sodium ion batteries in the monolayer VS 2 as well as an output voltage of 0.88 and 0.6 V in the bulk VS 2 , respectively. The calculated lithium and sodium ion diffusion coefficients in the bulk VS 2 are enhanced by five and seven orders of magnitude compared to the reported bulk MoS 2 , respectively. Our investigations also reveal that VS 2 exhibits better electrochemical performance as an anode in the sodium ion battery than in the lithium ion battery.

No abstract

Intense particle beams generated from the interaction of ultrahigh intensity lasers with sample foils provide options in radiography, high-yield neutron sources, high-energy-density-matter generation, and ion fast ignition. An accurate understanding of beam transportation behavior in dense matter is crucial for all these applications. Here we report the experimental evidence on one order of magnitude enhancement of intense laser-accelerated proton beam stopping in dense ionized matter, in comparison with the current-widely used models describing individual ion stopping in matter. Supported by particle-in-cell (PIC) simulations, we attribute the enhancement to the strong decelerating electric field approaching 1 GV/m that can be created by the beam-driven return current. This collective effect plays the dominant role in the stopping of laser-accelerated intense proton beams in dense ionized matter. This finding is essential for the optimum design of ion driven fast ignition and inertial confinement fusion.

No abstract

No abstract

A difference algebraic converging method for electron scattering from molecule (DACMe) is suggested based on the recently proposed difference converging method (DCM) to predict unknown differential cross sections (DCSs). The applications of the DACMe to electron scattering from tetrahydrofuran (THF) molecule at energies below 20 eV show that: (1) the DACMe DCSs excellently reproduce all the available experimental data; (2) the DACMe method correctly predicts unknown DCSs that may not be given experimentally; (3) the DACMe can be used as an economic and useful alternative method to predict the correct DCSs where such scattering data are required; (4) the DACMe method does not depend on the size and the stereochemistry structure of a scattering molecule; (5) the algebraic modification to the DCM enhances the computational efficiency of the DCM theoretical study by at least 110 times.

The existing potential energy surfaces for the Li + HF system have been challenged by the experiments of Loesch, Stienkemeier, and co-workers. Here a very accurate potential energy surface has been obtained with rather rigorous theoretical methods. Methods up to full CCSDT have been pursued with basis sets as large as core correlated quintuple ζ. Reported here are the reactants, products, two transition states, and three intermediate complexes for this reaction. These reveal one previously undiscovered equilibrium geometry. The stationary point relative energies are very sensitive to level of theory. The reaction has a classical endothermicity of 2.6 kcal mol(-1). The complex Li···HF in the entrance valley lies 6.1 kcal/mol below the reactants. The expected transition state Li···H···F is bent with an angle of 72.2° and lies 4.5 kcal/mol above the reactants. The latter predicted classical barrier should be no more than one kcal/mol above the exact barrier. Not one but two product complexes lie 1.6 and 2.2 kcal/mol above reactants, respectively. Between the two product complexes, a second transition state, very broad, is found. The vibrational frequencies and zero-point vibrational energies (ZPVE) of all stationary points are reported, and significantly affect the relative energies.