International Journal of Modern Physics B

The static dipole polarizabilities of the 1 ¹S $\sim$ 5¹S, 2³S $\sim$ 6³S states of helium are presented. Our results are accurate up to at least eight digits. The majority of ${}^{\infty }$He (infinite mass helium) data are better than the data derived by Yan with Hylleraas coordinates,${}^{13}$ and close to the newest results achieved by another method.${}^{18}$ We demonstrate the results of ⁴He besides.

In this paper, the structural, electronic and magnetic properties of small Fe${}_m$V${}_n$ (m+n $\le$ 6) clusters have been investigated systematically within the framework of the generalized gradient approximation density-functional theory. The results indicate that the low lying isomers of Fe${}_m$V${}_n$ alloy clusters all present the classical closely packed geometries with different chemical order when m + n $>$ 4; the ground state structures prefer to form the Fe–V as much as possible in small proportion V doping. The binding energy of Fe${}_m$V${}_n$ clusters always increases with the successive V substitution. The V atom mono-doped and bi-doped make the magnetism of Fe${}_n$ clusters decrease 7 ${\mu }_B$, respectively. With V atom doping increasing, the magnetism presents an overall decreased tendency. The magnetic order bewteen Fe and V atoms undergoes a transition from antiferromagnetic coupling in Fe-rich clusters to the coexistence of antiferromagnetic and ferromagnetic couplings in V-rich clusters, and the atom net charge usually transfer from V to Fe atom in Fe${}_m$V${}_n$ alloy clusters.

We apply equilibrium molecular dynamic simulations for investigating the infinite dilution diffusivity of carbon dioxide in near- and supercritical water (SCW) over the wide temperature ranging from 647 to 973 K at 115, 217, 426 and 663 kg/m³. The diffusion coefficients of SCW and infinite dilution diffusion coefficients (IDDCs) of carbon dioxide are calculated by using the Einstein mean-square displacement method. It is observed that the IDDCs of carbon dioxide in SCW are approximately 1–2 orders of magnitude higher than that in normal water. The analysis of the temperature dependence of the IDDCs of carbon dioxide reveals that they do not conform to the Arrhenius equation. In the near critical region, the IDDCs of carbon dioxide do not exhibit a monotonic change with a variation in temperature, but increase gradually with an increase in the temperature in a region far from the critical state. The anomaly of the temperature dependence of the diffusion of carbon dioxide in SCW can be explained using the microstructure features of the different states of the water. In addition, we observe that the IDDCs of oxygen are slightly larger than those of carbon dioxide under the same conditions.

In this study, we show that by applying appropriate deposition conditions, Zn nanostructured templates for the growth of zinc oxide (ZnO) nanowires can be fabricated, from which ultrafine high optical quality nanowires can be grown by means of post-deposition low-temperature oxidation. By identifying and optimizing the appropriate parameters, we successfully fabricated long ultrafine ZnO nanowires up to 30 microns in length and 50 nm in diameter. Our report contradicts the commonly held paradigm that sputter deposition can only be used to fabricate thin films with no significant nanostructure morphology and provides a low cost, high throughput method of fabricating different ZnO nanostructures. The studies of photoluminescence (PL) of the nanowires showed their high optical quality with band edge dominated emission with small defect-related input.

Synapse coupling is critical for information encoding of neurons. The effect of electromagnetic induction in cell becomes distinct when the exchange of charged ions across membrane is frequently triggered by external electric field or synapse current from adjacent neurons. In this paper, Gaussian white noise is imposed on a two-layer network composed of neurons with electromagnetic induction. The gap junction coupling is applied to connect the adjacent neurons and external stimulus with diversity is applied to keep different excitabilities of neurons in each layer. Neurons on the second layer are activated and modulated by using field coupling rather than channel coupling. It is found that the pattern formation on the network is much dependent on the initial setting due to the memory effect based on induction current via memristive synapse. Furthermore, field coupling intensity (D₀) and noise intensity (D₁) are changed to detect the development of spiral waves, target waves on the network in presence of noise. It confirms that noise can be helpful for pattern selection and synchronization approach on the two-layer network under field coupling, while field coupling can suppress the self-organization for pattern formation.

In this paper, combining phosphorescence and fluorescence to form white light was realized based on DCJTB:PMMA/ITO/NPB/TCTA/FIrpic:TCTA/TPBi/Ir(ppy)3:TPBi/TPBi/Cs₂CO₃/Al. The effects of red fluorescence on this white light device was studied by adjusting the concentration of DCJTB. The study shows that the device with a DCJTB concentration of 0.7% in the color conversion layer (CCL) generates a peak current efficiency and power efficiency of 23.4 cd ⋅ A${}^{-1}$ and 7.5 lm ⋅ W${}^{-1}$, respectively. And it is closest to the equal-energy white point of (0.33, 0.33) which shows a CIE (Commission Internationale de L’Eclairage) coordinate of (0.35, 0.43) and a color rendering index (CRI) of 70 at current density of 10 mA ⋅ cm${}^{-2}$. In order to improve the efficiency, we design and fabricate both high efficient and pure white organic light-emitting diode (WOLED) by replacing the single blue emission layer (EML) with double EMLs of FIrpic:TCTA and FIrpic:TPBi. The further study shows that, when the layers of EML is three and the concentration of DCJTB at 0.7%, the device exhibits good performance specifically, at current density of 10 mA ⋅ cm${}^{-2}$, the current efficiency of 28.2 cd ⋅ A${}^{-1}$ (power efficiency of 10.3 lm ⋅ W${}^{-1}$), and the CIE coordinate of (0.33, 0.31) (CRI of 80.38).

The aluminum-based intermetallic compounds AlZr₃, AlCu₃ and AlCu₂Zr are studied for elastic and mechanical properties by a DFT embodied in WIEN2k code with Generalized Gradient Approximation (GGA) as an exchange correlation functional. The cubic elastic parameters $C_{11}$, $C_{12}$ and $C_{44}$ are found keeping bulk modulus value the same as in the structural optimization. The mechanical properties such as Young’s modulus, shear modulus, anisotropic factor and Poisson’s ratio are then found using these fundamental parameters. It is found that our calculated results are in good agreement with available theoretical and experimental results.

In this paper, we have designed a rhombic microchannel plane micromixer (RMPM). The RMPM uses the principle of converging and diverging to improve the mixing efficiency. We improved the mixing efficiency by changing the rhombic angles and the rhombic channel width ratios. The influence of geometric parameters on mixing efficiency is analyzed by control of the variable method. Through the analysis of the numerical simulation, the RMPM can help increase the chaotic convection between different concentrations of fluids. The results of the study show that the rhombic angle and the width ratio of a microchannel can have a considerable effect on the mixing efficiency. The micromixer can be potentially useful in the future applications of rapid and high throughput mixing.

We have investigated the recollision dynamics of correlated electron from nonsequential double ionization (NSDI) with 3200 nm laser fields at a wide range of intensities using a full-dimensional classical ensemble method. The numerical results show that for the mid-infrared laser fields, the double ionization probability versus laser peak intensity still displays a much clear “traditional” knee structure representing NSDI. At low intensity, the electron momentum correlated spectrum along the laser polarization direction shows a V-shaped structure; whereas at high intensity, the spectrum exhibits a clearly cross-shaped structure. We demonstrate that both the V-shaped structure and the cross-shaped structure are the results of extremely asymmetric energy sharing of the two electrons at recollision. Moreover, the most prominent contribution to NSDI is from the second-returning trajectory and the first-returning trajectory is significantly suppressed. What’s more, the mechanism of NSDI is from recollision impact ionization (RII) channel as well as recollision-excitation-with-subsequent-ionization (RESI) channel. We find that at low intensity, only the RII channel contributes to V-shaped structure; whereas at high intensity, both the RII and RESI channels have comparable contribution to the cross-shaped structure. Further, we diagnose the recolliding electron and the bound electron separately by tracing the classical trajectories.

Crystal structure and thermophysical properties of BaFe${}_{12-x}$Ga${}_x$O${}_{19}$ solid solutions have been studied by X-ray diffraction, thermogravimetry and differential scanning calarimetry methods. It is determined that these compounds have characteristic transitions at 72${}^{\circ }$C and 85${}^{\circ }$C temperatures. From the spectra of the TG and DTG loss of mass and energy are determined in the temperature range of 30–950${}^{\circ }$C. At the temperature of T $\sim$ 120${}^{\circ }$C, the endoeffects are chemically absorbed water on the active surface of the compound and are a decomposition of the hydroxide group. The endoeffect, at which its central peak reaches T $\sim$ 80${}^{\circ }$C, is associated with an OH group that has been chemically absorbed, observed revised effects with a difference $\mathrm{\Delta }$T $\sim$ 35${}^{\circ }$C for relative decomposition at high-temperature.

The influence of vacancy and dopants on the adsorption of O₂ molecule on graphene was explored by using the density functional theory (DFT) method. The results indicated that the presence of vacancy-defect improved the sensitivity of graphene toward the O₂ molecule. Furthermore, the two O atoms of O₂ molecule separately formed chemical bonds with C atoms at the defect sites. After introducing the transition-metal (TM) dopants, the O–O bond length of O₂ molecule was enlarged by the adsorption on the surface of graphene. Furthermore, the Mn-doped adsorption complexes became magnetic, which was mainly contributed by the O-2p and Mn-3d orbitals.

The activity and solubility of Si in Mo solid solution were studied by the first-principles calculations and quasi-harmonic approximation. The lattice constants, bulk modulus, and formation enthalpies of Mo-Si intermetallics were investigated, and the thermodynamic properties of Mo were also calculated. The Si activity coefficient ${\gamma }_{\mathrm{\text{Si}}}$ is approximately 10${}^{-16}$ at 100 K, while it increases by about 15 orders of magnitude over the investigated temperature range (100–2000 K). It is clear that Si activity coefficient in Mo solid solution increased rapidly with the increasing temperature, which should be ascribed to the Si–Mo interaction being evidently stronger than Mo–Mo interaction. According to the calculated thermodynamic properties, the solubility curve of Si in Mo solid solution was also predicted. The solubility limit of Si in Mo solid solution is $\sim$5.5 at.%, which agrees well with the other experiment and assessed results.