Modern Physics Letters B

Polymer-based micro/nano fluidic devices are becoming increasingly important to biological applications and fluidic control. In this paper, we propose a self-enclosure method for the fabrication of large-area nanochannels without external force by using a capillary-pressure balance mechanism. The melt polymer coated on the nanogrooves fills into the trenches inevitably and the air in the trenches is not excluded but compressed, which leads to an equilibrium state between pressure of the trapped air and capillary force of melt polymer eventually, resulting in the channels’ formation. A pressure balance model was proposed to elucidate the unique self-sealing phenomenon and the criteria for the design and construction of sealed channels was discussed. According to the bonding mechanism investigated using the volume of fluid (VOF) simulation and experiments, we can control the dimension of sealed channels by varying the baking condition. This fabrication technique has great potential for low-cost and mass production of polymeric-based micro/nano fluidic devices.

Under investigation in this paper is a variable-coefficient generalized AB system, which is used for modeling the baroclinic instability in the asymptotic reduction of certain classes of geophysical flows. Bilinear forms are obtained, and one-, two- and three-soliton solutions are derived via the Hirota bilinear method. Interaction and propagation of the solitons are discussed graphically. Numerical investigation on the stability of the solitons indicates that the solitons could resist the disturbance of small perturbations and propagate steadily.

Cold work (compression) is an important method that produces dislocations mainly used to improve the mechanical properties of Al-alloys. The effect of deformation on 5754 Al-alloy was investigated by Positron Annihilation Lifetime Spectroscopy (PALS), Vickers micro-hardness (HV) and X-ray diffraction (XRD) techniques. The observation of results obtained by these techniques as a function of degree of deformation showed approximately the same behavior. Mean lifetime and Vickers micro-hardness values changed from 168.0 ± 7.0 ps and 32.0 ± 1.5 Hv, respectively, for the annealed (undeformed) sample to be 214.0 ± 7.0 ps and 43.0 ± 1.5 Hv, respectively, for saturated dislocation samples. Both PALS and HV results seems to be approximately constant above 8.0% degree of deformation which is the start of the saturated dislocation region. 10% degree of deformation is considered to be a threshold point or preferred orientation point obtained from XRD measurements after which saturation of dislocation is also obtained. Due to the variation in the interatomic spacing caused by plastic deformation, a significant increase in the peak broadening and line intensities of the XRD reflections is obtained.

In this paper, we investigate the steady-state properties of a piecewise nonlinear bistable model driven by multiplicative and additive Gaussian colored noises with colored cross-correlation. Using the unified colored noise approximation, we derive the analytical expression of the steady-state probability density (SPD) function. Then the effects of colored correlated Gaussian colored noises on SPD are presented. According to the research results, it is found that there appear some new nonlinear phenomena in this system. The multiplicative colored noise intensity, the additive colored noise intensity and the cross-correlation strength between noises can induce the transition. However, the transition cannot be induced by the auto-correlation time of multiplicative and additive Gaussian colored noises as well as the cross-correlation time between noises.

The effects of temperature and neutron irradiation on the silicon nanoparticles have been studied at different frequencies. It has been defined that additional electro-active radiation defects occur in the silicon nanomaterial after neutron irradiation. Therefore, the change of neutron flux at the interval of $6.7\times 10^{17}$–$2.7\times 10^{18}\mathrm{\text{n}}\cdot {\mathrm{\text{cm}}}^{-2}{\mathrm{\text{s}}}^{-1}$ increases the conductivity of nanosilicon. Activation energies of the silicon nanoparticles were calculated for 10 different constant frequencies according to Arrhenius approach before and after neutron irradiation. The mechanism of electrical conductivity which explains results has been established.

In this paper, we investigate a nonlinear fiber described by a (2+1)-dimensional complex Ginzburg–Landau equation with the chromatic dispersion, optical filtering, nonlinear and linear gain. Bäcklund transformation in the bilinear form is constructed. With the modified bilinear method, analytic soliton solutions are obtained. For the soliton, the amplitude can decrease or increase when the absolute value of the nonlinear or linear gain is enlarged, and the width can be compressed or amplified when the absolute value of the chromatic dispersion or optical filtering is enhanced. We study the stability of the numerical solutions numerically by applying the increasing amplitude, embedding the white noise and adding the Gaussian pulse to the initial values based on the analytic solutions, which shows that the numerical solutions are stable, not influenced by the finite initial perturbations.

Based on the recent progresses on the corresponding state-based correlations for the temperature-dependent surface tension of saturated fluids [I. Cachadiña, A. Mulero and J. X. Tian, Fluid Phase Equilibr. 442 (2017) 68; J. X. Tian, M. M. Zheng, H. L. Yi, L. B. Zhang and S. Z. Liu, Mod. Phys. Lett. B 31 (2017) 1750110], we proposed a new correlation for saturated hydrocarbons. This correlation includes three fluid-independent parameters and inquires the critical temperature, the triple-point temperature and the surface tension at the triple-point temperature as inputs for each hydrocarbon. Results show that this correlation can reproduce NIST data with absolute average deviation (AAD) less than 1% for 10 out of 19 hydrocarbons and AAD less than 5% for 17 out of 19 hydrocarbons, clearly better than other correlations.

The neutral, anionic and cationic bismuth clusters with the size n up to 14 are investigated by using B3LYP functional within the regime of density functional theory and the LAN2DZ basis set. By analysis of the geometries of the Bi${}_n$ (n = 2–14) clusters, where cationic and anionic bismuth clusters are largely similar to those of neutral ones, a periodic effect by adding units with one to four atoms into smaller cluster to form larger cluster is drawn for the stable structures of bismuth clusters. An even–odd alteration is shown for the properties of the clusters, such as the calculated binding energies and dissociation energies, as well as frontier orbital energies, electron affinities, ionization energies. All the properties indicate that the Bi₄ cluster is the most possible existence in bismuth-containing materials, which supports the most recent experiment. The orbital compositions, infrared and Raman activities and the ultraviolet absorption of the most possible tetramer bismuth cluster are given in detail to reveal the periodic tendency of adding bismuth atoms and the stability of tetramer bismuth cluster.

The skutterudite CoSb${}_{2.75}$Te${}_{0.20}$Sn${}_{0.05}$ compound was synthesized successfully by high pressure and high temperature (HPHT) method using Co, Sb, Te and Sn powder as raw materials. The effects of pressure on its structure and the thermoelectric properties are investigated systematically from 300 K to 800 K. The electrical resistivity and the absolute value of the Seebeck coefficient for the sample increases with rising synthetic pressure. The thermal conductivity of the sample decreases with synthetic pressure and temperature rising in the range of 300–800 K. In this study, the maximum dimensionless figure of merit (ZT) value of 1.17 has been achieved at 793 K, 3 GPa for this thermoelectric material.

A broad general interest in the process of affecting the energetic deposition of flying nanoparticles has prompted a new opportunity to consider the medium-energy region in which the nanoparticles maintain their integrity and must respond to the energetic shock caused by collisions. We herein report our experimental results on the structural transition of the carbon nanoparticles induced by such energetic collisions. The beam energy was varied from 0 keV to 30 keV for a nanoparticle with over 5000 carbon atoms. Electron energy loss spectroscopy, X-ray photoemission spectroscopy, and Raman spectroscopy were carried out on the samples using a series of beam energies. These tests revealed that some graphitic sheets were formed at the higher beam energy while the sp³ ratio was unexpectedly higher for a medium beam energy.