Effects of Isotope Substitution on Local Heating and Inelastic current in Hydrogen Molecular Junctions

Using first principle approaches, we investigate the effects of isotope substitution on the inelastic features in the hydrogen molecular junction. We observe thatlocal heating and inelastic current have significant isotope-substitution effects. Due to the contact characters, the energies of excited molecular vibrationsare inverse proportional to the square root of the mass. The heavier the molecule, the smaller the onset bias. In the $H_{2}$ and $D_{2}$ junctions, the heavier molecule has a smaller magnitude of electron-vibration interaction. Consequently, there is a crossing in the local temperature around $80 K$. In the HD junction, the electron-vibration interaction is enhanced by asymmetric distribution in mass. It leads to the largest discontinuity in the differential conductance and the most prominent heating in the HD junction. We predict that the junction instability is relevant to isotope substitution. The HD junction has the smallest breakdown voltage compared with the $H_{2}$ and $D_{2}$ junction

High dimensional generalized empirical likelihood for moment restrictions with dependent data

This paper considers the maximum generalized empirical likelihood (GEL) estimation and inference on parameters identified by high dimensional moment restrictions with weakly dependent data when the dimensions of the moment restrictions and the parameters diverge along with the sample size. The consistency with rates and the asymptotic normality of the GEL estimator are obtained by properly restricting the growth rates of the dimensions of the parameters and the moment restrictions, as well as the degree of data dependence. It is shown that even in the high dimensional time series setting, the GEL ratio can still behave like a chi-square random variable asymptotically. A consistent test for the over-identification is proposed. A penalized GEL method is also provided for estimation under sparsity setting

Plasma Suppression of Large Scale Structure Formation in the Universe

We point out that during the reionization epoch of the cosmic history, the plasma collective effect among the ordinary matter would suppress the large scale structure formation. The imperfect Debye shielding at finite temperature would induce a residual long-range electrostatic potential which, working together with the baryon thermal pressure, would counter the gravitational collapse. As a result the effective Jean's length, $\tilde{\lambda}_J$, is increased by a factor, $\tilde{\lambda}_J/\lambda_J=\sqrt{8/5}$, relative to the conventional one. For scales smaller than the effective Jean's scale the plasma would oscillate at the ion-acoustic frequency. The modes that would be influenced by this effect depend on the starting time and the initial temperature of reionization, but roughly lie in the range $0.5 h{\rm Mpc}^{-1}< k$, which corresponds to the region of the Lyman-$\alpha$ forest from the inter-galactic medium. We predict that in the linear regime of density-contrast growth, the plasma suppression of the matter power spectrum would approach $1-(\Omega_{dm}/\Omega_m)^2\sim 1-(5/6)^2\sim 30$.Comment: 4 pages and 2 figure

A third-order discrete unified gas kinetic scheme for continuum and rarefied flows: low-speed isothermal case

An efficient third-order discrete unified gas kinetic scheme (DUGKS) with efficiency is presented in this work for simulating continuum and rarefied flows. By employing two-stage time-stepping scheme and the high-order DUGKS flux reconstruction strategy, third-order of accuracy in both time and space can be achieved in the present method. It is also analytically proven that the second-order DUGKS is a special case of the present method. Compared with the high-order lattice Boltzmann equation {LBE} based methods, the present method is capable to deal with the rarefied flows by adopting the Newton-Cotes quadrature to approximate the integrals of moments. Instead of being constrained by the second-order (or lower-order) of accuracy in time splitting scheme as in the conventional high-order Runge-Kutta (RK) based kinetic methods, the present method solves the original BE, which overcomes the limitation in time accuracy. Typical benchmark tests are carried out for comprehensive evaluation of the present method. It is observed in the tests that the present method is advantageous over the original DUGKS in accuracy and capturing delicate flow structures. Moreover, the efficiency of the present third-order method is also shown in simulating rarefied flows

The relationships between corruption and pollution on corruption regimes

Previous studies have focused mainly on the effect of corruption on pollution. The results of these studies show an inverted U-shaped relationship between economic growth and pollution. In addition, some researchers have suggested that corruption plays an important role in determining pollution. This study proposes the hypothesis of a nonlinear long-run relationship between pollution and corruption. The goal of the study is to investigate the threshold cointegration effect of pollution on corruption using panel data for 62 countries over the period from 1997 to 2004. The results show that the effect of the Corruption Perceptions Index (CPI) on pollution is insignificant in low-corruption regimes. This implies that corruption does not slow down environmental pollution in countries with low corruption. The impact of the CPI on environmental pollution is also insignificant in high-corruption regimes. This result implies that corruption has no adverse impact on environmental pollution in countries with high corruption.Corruption, Pollution, Threshold, Error-Correction Model

Counting similarities between tetraquark and mesonic/gluonic operators

After the study of the preclusion of exotic meson states in large-$N_c$ limit QCD, combining Weinberg's opposite proposal, we get different counting orders for a tetraquark operator to create or destroy an one-tetraquark state. Meanwhile, by comparing tetraquark operator with the mesonic and gluonic operators, we find that tetraquark operators are similar with mesonic and gluonic operators in the counting. Furthermore, we find a mixing of different kinds of operators.Comment: 4 page