Random numbers are used to encrypt the information in the field of secure communications. According to one-time pad theory found by Shannon, the absolute security of the high-speed communication requires the ultrafast reliable random numbers to be generated in real-time.Using complex algorithms can generate pseudorandom numbers, but they can be predicted due to their periodicity. Random numbers ba...
In complex networks, the node importance evaluation is of great significance for studying the robustness of network. The existing methods of evaluating the node importance mainly focus on undirected and unweighted networks, which fail to reflect the real scenarios comprehensively and objectively. In this paper, according to the directed and weighted complex network model, by analyzing the local im...
In the study of electromagnetic scattering of multi-target composite on and above the rough sea surface, the common algorithm such as the method of moment analyzes the relationship between the target and the rough sea surface point by point, so the common algorithm usually requires massive computation and a lot of time. In this paper, the rough sea surface is described by Pierson-Moscowitz (PM) sp...
Particle filer is apt to have particle impoverishment with unstable filtering precision, and a large number of granules are required to estimate the nonlinear system accurately, which reduces the comprehensive performance of the algorithm. To solve this problem, a new particle filter based on bat algorithm is presented in this paper, where particles are used to represent individual bat so as to im...
ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS
Cirrus is an important regulator for the flow of radiant energy in the earth-atmosphere system through the processes of scattering and absorption of radiation. In order to satisfy the urgent requirement for accurate retrieval of cirrus microphysical properties, terahertz wave is expected to be the best waveband for inverting cirrus particle size and ice water path, with terahertz wavelengths on th...
Traditional imaging spectropolarimetry generally requires slit, moving parts, electrically tunable devices, or the use of micropolarized arrays. Furthermore, the acquired raw data are a physical superposition of interferogram and image. Given their complicated structure, poor seismic capacity, low detection sensitivity, and heavy computations with approximation in spectral reconstruction, meeting ...
Zone plate coded imaging is an experimental technique for particle and strong X-ray imaging, which is widely applied to astronomy, nuclear medicine, and laser inertial confinement fusion researches. From conventional perspective, spatial resolution of zone plate depends on the encoding zone plate width of outermost ring r with a size greater than 1.22r. In X-ray region, however, the outermost ring...
The target gas molecular absorption spectrum parameters especially line strengths are very important for measuring temperature and concentration with tunable diode laser absorption spectroscopy (TDLAS) technique. Usually, researchers use line strengths which come from spectrum database, like HITRAN and GEISA and HITEMP spectra database, but those database include values from the theoretical comput...
There has been a resurgence in the field of magnetohydrodynamic (MHD) flow control in the past 20 years. An increasing demand for sustained hypersonic flight and rapid access to space, along with numerous mechanical and material advances in flight-weight MHD technologies, has aroused renewed interest in this subject area. As a novel application of MHD flow control in the thermal protection field, ...
It is known that polarization as the third characteristic of electromagnetic waves plays substantial roles which are comparable with the wave amplitude and phase, in describing the tempo and spatial properties of electromagnetic waves. Various parameter groups for characterizing the polarization state of electromagnetic waves with different initial states and boundary conditions have been proposed...
In this paper, a new kind of quasi-boson method is used to eliminate the coordinates of the environment and redescribe the dissipative system by using an effective Hamiltonian; the localized mode and the interaction between cavities can be renormalized. Based on the quasi-boson approach, the single photon transport in one-dimensional coupled cavity array, with a driven cascade-type three-level ato...
With the rapid development of space technology, human activities into space are increasing, thereby producing lots of space debris. And the space debris impact is the major cause for the mechanical damage to the space crafts and the main factor affecting the service life; it even endangers the life safety of the astronauts working outside the spacecraft and pose a threat to the astronomical observ...
Until now, there have been many reports concerning the generation and propagation of partially coherent beams due to their less influencing ability in turbulent atmosphere and random media. Of particular interest, a Gaussian-Schell model beam has been widely chosen as a special example of partially coherent beam, since its spatial coherence degree is dependent on position only through the differen...
The objective of this study is to investigate the flow structure of underwater supersonic gas jets in water flow. Supersonic gas jets submerged in a liquid flow field is experimentally studied in a water tunnel. In the experiments, a high speed camera system is used to observe the evolution of the gas jet bubble, and a dynamic pressure measurement system is used to measure the pressure fluctuation...
Grating based X-ray imaging technology is a coherent imaging technique that bears tremendous potential in three-dimensional tomographic imaging of weak absorption contrast specimens. Three kinds of contrast information including absorption, phase and scattering can be retrieved separately based on a single set of raw projections. However, the grating based X-ray imaging with the conventional phase...
The safety quality of vegetable oil is very important for human life. The objective of this research is to determine the content of heavy metal chromium (Cr) in each of three kinds of vegetable oils (soybean oil, peanut oil, and corn oil) quantitatively by collinear double pulse laser-induced breakdown spectroscopy (DP-LIBS). In this study, a total of 24 vegetable oil samples are prepared, and eac...
We study the new spatial optical solitons and their propagating properties in the one-dimensional nonlocal cubic-quintic (C-Q) nonlinear model by the numerical method. We obtain multi-bright solitons and multipole soliton solutions in the one-dimensional nonlocal C-Q nonlinear model. The propagation of bright solitons is stable in the competing nonlocal cubic self-defocusing and quintic self-focus...
Electronic diode plays an important role in electronic circuits owing to its capability of unidirectional movement of the current flux. An optical diode offers unidirectional propagation of light beams, which plays key roles in the all-optical integrated circuits. Unidirectional wave propagation requires either time-reversal or spatial inversion symmetry breaking. The former can be achieved with t...
THz waves are very good candidates for high-capacity wireless links since they offer a much higher bandwidth than RF frequencies. Photonic crystal (PC) offers a new opportunity for integrated THz wave devices. It permits the integrated devices to be miniaturized to a scale comparable to the wavelength of the electromagnetic wave. Considering their governing properties such as photonic band gap (PB...
SiO2 thin film is one of the most important low refractive index materials in the area of optical thin films. It is always used in the design and preparation of many kinds of multilayer films. The dielectric constant of the SiO2 thin film is a key characteristic for design of the multilayer thin film. The composite Gaussian oscillator model is one of the most important dispersion models for the di...
The Hamilton-Jacobi equation is an important nonlinear partial differential equation. In particular, the classical Hamilton-Jacobi method is generally considered to be an important means to solve the holonomic conservative dynamics problems in classical dynamics. According to the classical Hamilton-Jacobi theory, the classical Hamilton-Jacobi equation corresponds to the canonical Hamilton equation...
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
The electromagnetic surface waves which propagate along a non-magnetized cold plasma column have a great value in the application of plasma antenna. In this paper, the dispersion properties, the transmission power distributions, and the radiation patterns for these electromagnetic surface waves which have lower frequencies than the electron plasma frequency are analyzed numerically. Based on Helmh...
Micro hollow cathode sustained discharge (MCSD) is simulated by using a fluid model, and the spatiotemoral characteristics of the electric potential, electron density, ion density and electric field are investigated. Results show that the MCSD acts in different modes at different times. The first stage is the Townsend discharge mode. The second is a transition mode from Townsend discharge mode to ...
Coaxial gun discharge plasma with high density and velocity has a number of potential applications in fusion energy, plasma refueling, disruption mitigation in tokamaks, plasma space propulsion, acceleration of dust particles to hypervelocity etc., and thus has become an important research topic in fields of nuclear physics and aerospace engineering. In this paper, we report the experimental inves...
Intense pulse ion beam (IPIB) has been extensively used in material surface modification. The ablation effect plays an important role in the interaction between IPIB and material. Therefore, the understanding of ablation mechanism is of great significance for IPIB application. Here, to investigate the ablation process and the characteristics of ablation products, pure zinc targets are bombarded by...
One-atom-thick material such as graphene, graphene derivatives and graphene-like materials, usually has a dense network lattice structure and therefore dense distribution of electronic clouds in the atomic plane. This unique structure makes it have great significance in both basic research and practical applications. Studies have shown that molecules, atoms and ions are very difficult to permeate ...
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
A first-principles plane-wave pseudo potential method based on the density functional theory is used to investigate the phase structures, energies, electronic structures and elastic properties of Ti3AC2 (A=Si, Sn, Al, Ge) phases. In this paper, Ti3AC2 (A=Si, Sn, Al, Ge) crystal structures are first optimized, then the band structures, total and part density of states,charge density distributions a...
As a stable single sheet of carbon atoms with a honeycomb lattice, graphene has become attractive for its potential applications in electrochemical storage devices, such as anodes for rechargeable Li batteries. Since both sides of it can hold adsorbents, a graphene sheet is expected to have extra storage sites and therefore it has a possibly higher capacity than graphite. However, certain shortcom...
In the layered dichalcogenide 1T-TaS2, whether there is a disorder-driven transition from insulator to metal is still a matter in dispute. It is predicted that the commensurate charge density wave (CCDW) phase at low temperature behaves as a Mott insulator due to the strong correlation of electrons. Meanwhile, the stacking of TaS layers is found to be dislocated along the c axis, which will introd...
The rapid development of organic-inorganic hybrid perovskite solar cells has recently attracted the worldwide attention because their power conversion efficiency has risen from 4% to higher than 20% within just six years. It is well known that the perovskite materials with APbI3 crystal structure have a 3D framework of corner-sharing PbI6 octahedra, in which each Pb atom bonds with six I atoms, an...
Aluminum and its alloy play an important role in nuclear industry, where irradiation damage continually occurs and significantly affects the structures and physical properties of materials: especially long-term irradiation can lead to the formation of helium bubbles and holes in the substrate. During the initial irradiation damage, point defects are the major defects.Studying the point defects is...
Alloy nanoclusters have received extensive attention because they can achieve bifunctional properties by making good use of the cooperative effect of two metals. In this paper, an improved Basin-Hopping Monte Carlo (BHMC) algorithm is proposed to investigate the structural stabilities of Fe-Pt alloy nanoclusters. Different cluster sizes and chemical compositions are considered. Moreover, a similar...
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
Compared with conventional semiconductors, the diluted magnetic semiconductors, in which the cations are substituted by transition metal ions, have attracted a great deal of attention due to their promising applications in spintronics. Recently, the unexpected room temperature ferromagnetism has been found in many undoped oxides. These findings challenge our understanding of magnetism in these sys...
Porous material contains a large number of pores, and once the pore space collapses, it changes into a dense material with the great increase of temperature because of the energy deposition by porosity collapsing. In the process of shock compression, the temperature is extremely increased, which influences the thermodynamic state of porous material significantly. Therefore, the calculation of temp...
Polyethylene (PE) is an important kind of plastic, which plays a significant role as the shell material of the fuel capsule, light weight structural element subjected to intense mechanical impact and explosion load. And it is well accepted that semi-empirical three-term equation of state (EOS) is one of the most widely used EOSs in practical work. Therefore, studies of semi-empirical three-term EO...
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
Chemical vapor deposition is widely utilized to synthesize graphene with controlled properties for many applications. And it is one of the most important methods for the preparation of graphene with high quality in large area. Cu substrate is most commonly used for the preparation of graphene in chemical vapor deposition. As is well known, the properties of graphene are greatly affected by the num...
Unlike the traditional models, a new stereo photographic model requiring no sea control points that are difficult to lay on a sea surface is developed in this paper. It is realized according to the order of camera intrinsic parameters calibration, relative orientation and absolute orientation based on average sea surface, and we give the governing equations and its algorithms. First of all, in the...
Ionospheric heating experiments have been conducted widely at high power heating stations, such as Arecibo, Platteville, HAARP, etc. It has been found that once high-power high-frequency (HF) radio wave is injected into the ionosphere, the electron temperature and density in the illuminated region of the ionosphere can be disturbed, and furthermore, a large number of nonlinear phenomena may be tri...
X-ray pulsar navigation is a complete autonomous navigation system, which has broad application prospects. Because of the huge cost of the navigation system, the implementation of ground simulation system is essential to the application of X-ray pulsar navigation. At present, most of researches on the semi physical experiment system are static. The aim of this article is to develop the dynamic sim...