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An innovative divertor concept, the Fish Tail Divertor, is proposed in this paper, aiming at reducing the peak heat load on the tokamak divertor plate as well as that due to the edge localized modes. This new concept has been implemented in experiments to demonstrate its capability of strike point sweeping on the plate at the frequency range from ten to one hundred Hz by using an oscillating magnetic field. The strike point movement of 5-6 cm is achieved by applying a coil current of several percent of plasma current, leading to a significant reduction of heat load on the divertor target plate. The result indicates a possible application in a fusion reactor.

One of the greatest triumph of condensed matter physics in the past ten years is the classification of materials by the principle of topology. The existence of topological protected dissipationless surface state makes topological insulators great potential for applications and hotly studied. However, compared with the prosperity of strong topological insulators, theoretical predicted candidate materials and experimental confirmation of weak topological insulators (WTIs) are both extremely rare. By combining systematic first-principles calculation and angle-resolved photoemission spectroscopy measurements, we have studied the electronic structure of the dark surface of the WTI candidate Zintl Ba3Cd2Sb4 and another related material Ba3Cd2As4. The existence of two Dirac surface states on specific side surfaces predicted by theoretical calculations and the observed two band inversions in the Brillouin zone give strong evidence to prove that the Ba3Cd2Sb4 is a WTI. The spectroscopic characterization of this Zintl Ba3Cd2N4 (N = As and Sb) family materials will facilitate applications of their novel topological properties.

The chief aim of this paper is to control groove morphology precisely. In this paper, a 2D temperature field model for ultrafast picosecond laser grooving was set up on the foundation of the two-temperature model coupled with the phase change model. Then, a series of simulations were executed to investigate the influence of laser parameters such as laser power, scanning speed and repetition rate on ultrafast picosecond laser grooving. Finally, a number of experiments were performed to verify the model. The results suggest that the laser power has an obvious influence on the groove width and depth because the heat-affected zone area and single-pulse laser energy increase when the laser power varies from 2 W to 5 W. Obvious impacts of scanning speed on the groove depth and quality are observed in the present simulation due to the variation of overlap between sequential pulses and pulse numbers. The groove width and quality depend on the repetition rate. This is because the increase in the repetition rate has a certain contribution to increasing the temperature of heat residue and pulse number. This research contributes to present theoretical guidance on laser grooving.

A recent theory suggests that electrons enter electron sheaths at an electron Bohm velocity given by (T e/m e)1/2 instead of the electron thermal velocity as conventionally assumed. To test this theory, the flux density ratio Γe,se/Γi,se of electrons and ions entering their respective sheaths was directly measured via an almost continuous A i/A e area ratio scanning. The measured value agrees with the predictions assuming electrons entering the electron sheaths at their thermal velocity. The predictions associated with the electron Bohm criterion have not been found. If the predictions of such theories are true, the electron or ion presheath density drops will be very different from conventionally expected values.

Measuring flow field information in wind tunnel is an indispensable basic condition for aerodynamic research. Traditional measuring equipments include phase Doppler particle analyzer, hot wire anemometer, particle image velocimeter, etc. Particle image velocimeter can visualize the flow field, but its installation and debugging are complicated. To obtain flow field information quickly and realize visualization, a kind of technology based on hand-held probe is designed. The velocity of the flow field is calculated by the probe, and the position and attitude information of the probe is obtained by a kind of visual measurement system (Optotrak system), The spatial velocity distribution is fused with the position and attitude information of the probe, and then the flow field in the test area is graphically displayed by interpolation with mathematical tools. By using this technique to carry out test in wind tunnels, taking segment of the airfoil as the test object, and the dynamic measurement of the probe at the rear of the airfoil, the complex vortical flow generated by segment of the airfoil is successfully plotted. The test result shows the device used in this technology is simple in structure and flexible in use and can quickly acquire flow field information, which provides a new method and idea for flow field measurement.

The propagation of radio waves can be significantly affected by the ionosphere, which have a serious impact on broadcasting, communication, positioning and navigation. The International Reference Ionosphere (IRI) provides multiple ionospheric parameters for given location, time and date. In order to study the applicability of the IRI-2016 model in polar ionosphere, long-term observations from the dynasonde at Tromso (TRO), EISCAT Svalbard Radar (ESR) at Longyearbyen (LYB) and digisonde DPS-4 at Zhongshan (ZHS) were used to analyze the prediction accuracy of IRI model, with the help of mathematical statistics, correlation coefficients and time series. The data of F2 layer peak electron density (NmF2) are sorted as monthly medians of NmF2 for each hours, months, and solar activities. The results show that there is a good correlation between IRI prediction and observations during solar minimum years, with the correlation coefficients larger than 0.8 except winter at Longyearbyen, better than that during solar maximum years. The correlation decreases as latitude increases. It is the best at Tromso, and better at Zhongshan than at Longyearbyen. This suggests that the IRI-2016 model is mostly applicable at the auroral latitude station Tromso. But the IRI-2016 model has poor applicability at the cusp latitude station, both Zhongshan and Longyearbyen.

Divertor detachment achieved by injecting impurities or increasing density is always accompanied with various local radiation phenomena in the boundary or core plasma. This paper presents the formation and evolution of the high-field-side (HFS) radiation belts during the neon seeding plasma discharge in upper single null configuration with two directions of toroidal magnetic field in EAST tokamak. The neon mixed with deuterium seeding can induce the divertor detachment with strong radiation belts in the HFS scrape-off layer (SOL) region. With the increase of the radiation power, the plasma discharge will transit from H-mode to L-mode, and meanwhile the radiation belts move away from the near X-point to HFS SOL. When the radiation power is high enough, the radiation belts begin to move further to the other X-point along the HFS SOL, and even cause plasma disruption. The results indicate that the behavior of the radiation belts is related to the radiation power, plasma confinement performance and state of divertor detachment, which is useful for developing better feedback control methods to achieve high-performance radiative divertor operation mode.

With the rapid development of the scale and structure of the power grid, the power dispatching center has built a complete dispatching exchange communication network, which can meet the daily dispatching communication needs, but various problems are also emerging in the dispatching process. Aiming at the problem of high integration of physical power grid and information system, this paper proposes a voice backtracking system for power dispatching based on knowledge base, which includes knowledge base establishment, knowledge storage, knowledge question answering sorting and knowledge base front-end question answering. Firstly, the basic model of power dispatching knowledge processing is trained, and then the knowledge is extracted from the domain corpus, and finally, the knowledge question answering is realized by using the ranking model. Through the experimental comparison, it is proved that the accuracy of the method in this paper is higher than that of the method in the postprocessing by adding the MRC model in the pre-processing of knowledge extraction, and it is better than other methods in the comparative test. It provides technical support for power system voice dispatching management and provides a reference for other areas of voice management.

A series of L-mode discharges have been conducted in the new ‘corner slot’ divertor on the Experimental Advanced Superconducting Tokamak (EAST) to study the divertor plasma behavior through sweeping strike point. The plasma control system controls the strike point sweeping from the horizontal target to the vertical target through poloidal field coils, with keeping the main plasma stability. The surface temperature of the divertor target cools down as the strike point moves away, indicating that sweeping strike point mitigates the heat load. To avoid the negative effect of probe tip damage, a method based on sweeping strike point is used to get the normalized profile and study the decay length of particle and heat flux on the divertor target λ js, λ q. In the discharges with high radio-frequency (RF) heating power, electron temperature T e is lower and λ js is larger when the strike point locates on the horizontal target compared to the vertical target, probably due to the corner effect. In the Ohmic discharges, λ js, λ q are much larger compared to the discharges with high RF heating power, which may be attributed to lower edge T e.

The study of constitutive model of composite solid propellant is an important basis for analyzing the structural integrity of propellant grains of the solid rocket motor. From the view of microscopic, composite solid propellant is composed of a large number of solid particles with various sizes embedded in the matrix. In this paper, based on the distribution of solid particles with different sizes and the failure strength of the particle-matrix interfaces, the damage evolution was assumed to obey the Weibull distribution function and power law distribution function, and the two statistical damage constitutive models were first established. Then, the model parameters were identified and validated through the uniaxial tensile tests data of HTPB propellant. Finally, the prediction abilities of the developed two models were compared. The results show that both of the two statistical damage models can describe the stress-strain curves of HTPB propellant well.

Langmuir probe diagnostic in a multi-dipole confined hot cathode discharge has been revisited with an improved sheath expansion model with fitted expansion parameters. The results show a three-temperature Maxwellian EEDF composition also observed in previous studies using a very similar system. The dependence on neutral pressure and discharge current of each electron species are consistent with known physical processes in a multi-dipole confined hot cathode discharge. This shows that the employment of the new ion saturation fitting method does not eliminate the contribution of the high energy degraded primaries to the Langmuir probe I–V trace, as sheath expansion and high energy electron current contributes differently on an I–V trace. The result remains supportive to the existence of a very hot (T dp > 15 eV) degraded primary electron species separate from the typical hot electron (T hot ∼ 3 eV) species. Thus it is recommended to sweep the Langmuir probe beyond the bias voltage of the hot cathode, whenever possible, in order to properly resolve the contribution to the I–V trace of the degraded primaries.

A fibre Bragg grating (FBG)-based load and vibration transducer (FLVT) was developed using a 3D fused deposition modelling (FDM) approach. A newly FLVT was designed by the equal-strength cantilever beam in which the FBG sensors were embedded in the beam during the FDM process. The temperature effect was eliminated by the temperature sensor in the vibration sensing unit. The parameters of the proposed FLVT was examined by the finite element method. The simulated results were matched well with the theoretical analysis results and laboratory calibration results. The proposed transducer has the pressure measurement sensitivity of 0.01274 nm kPa−1 for the earth pressure below 150 kPa. In addition, the proposed transducer could accurately measure low-frequency vibration signals with maximum frequency of 4 Hz and the maximum displacement amplitude of 4 mm with sensitivity of 117.6 pm g−1. The measurement accuracy and stability were carried out. Results shown that the maximum relative errors between the calculation results and the experimental results was 1.3%. The effect of vibration direction was also analysed for the proposed FLVT. The results indicated that the transversal vibration has less influence on the longitudinal vibration. The outcome of this study indicated that the proposed FLVT provide a newly approach for the measurement of earth pressure and soil vibration in one transducer which is quit suit for soil mass.

In the contact interaction model, the quark propagator has only one solution, chiral symmetry breaking solution, at vanish temperature and density. Inspire by Y. Jiang and Z.-F. Cui, we introduce 2+1 flavors quark condensates feedback on coupling strength, the Wigner solution appears in some region of parameters. It enables us to tackle chiral phase transition as two-phase coexistences. At finite chemical potential, we analyze the chiral phase transition to the conditions of electric charge neutrality and $\beta$ equilibrium. The four chemical potentials, $\mu_u$, $\mu_d$, $\mu_s$ and $\mu_e$, are constrained by three conditions, there is one independent variable that remained, we choose the average quark chemical potential as the free variable. All quark masses and number densities suffer discontinuities at the phase transition point. The strange quarks appear after the phase transition due to the system needs more energy to produce a d-quark than an s-quark. Take the EOS as an input, the TOV equations are solved numerically, we show that the mass-radius relation is sensitive to the EOSs. The maximum mass of strange quark stars is not susceptible to our introduced parameter $\Lambda_q$., Comment: To be published in Chinese Physics C

We discuss the chiral and pion-superfluidity phase transitions at finite isospin chemical potential within the framework of Dyson–Schwinger equations. With the help of the quark scalar and pseudo-scalar condensates, which are widely accepted as order parameters of chiral and pion-superfluidity phase transitions respectively, we show that there is a second-order phase transition at isospin chemical potential μ I ∼ m π . Thereafter, we investigate the isospin effects on the chiral phase transition and on the critical point as well as the critical end point (CEP). The chiral phase transition line splits into two lines at finite μ I , and the CEP splits into two CEPs as well.

We report the tip-induced superconductivity on the topological semimetal NbSb2, similar to the observation on TaAs2 and NbAs2. Belonging to the same family of MPn 2, all these materials possess similar band structures, indicating that the tip-induced superconductivity may be closely related to their topological nature and share a common mechanism. Further analysis suggests that a bulk band should play the dominant role in such local superconductivity most likely through interface coupling. In addition, the compatibility between the induced superconductivity and tips’ ferromagnetism gives an evidence for its unconventional nature. These results provide further clues to elucidate the mechanism of the tip-induced superconductivity observed in topological materials.

Emission characteristics of a directly heated, rod-shaped LaB6 hot cathode has been studied in a multi-dipole confinement device. It is found that contrary to predictions from the conventional space-charge limited emission theory, emission current is not simply limited to a maximum value but eventually extinguished by space-charge related effects. In addition, directional preference of electron emission towards the positive lead of the applied heating voltage can be visibly observed. Results suggest that thermionically emitted electrons trapped in the virtual cathode are pumped towards the high voltage lead of the applied heating, and that the magnetic effects for filament heating currents exceeding 50 A may be the underlying mechanism of extinguishment; that is, the gyromotion of surface emitted electrons for sufficiently great heating currents may prevent electrons from escaping the virtual cathode. Geometrical effects are also briefly discussed.

ZnO–TiO2 nanowire composites with different Zn/Ti molar ratios were prepared by one-step hydrothermal process. The crystal structure, surface morphology and chemical state of the samples were characterized by XRD, SEM, TEM and XPS. The effect of ZnO content on the photocatalytic performance was investigated by degradation of Rhodamine B dye under xenon lamp illumination. The XRD result indicated that Zn/Ti molar ratio significantly affected the crystallinity and phase composition of ZnO–TiO2 composites. SEM images showed that ZnO nanoparticles of smaller size were dispersed on the surface of TiO2 nanowires and aggregated in the TiO2 framework. The optimal Zn/Ti molar ratio of 5% was obtained with highest photocatalytic activity, which could be attributed to the superior charge separation ability.

Appropriate financial software is the foundation of strengthening the enterprise information construction. For enterprises, choosing appropriate financial software is not only conducive to improving the efficiency and profitability of business processing, but also to ensuring the authenticity of financial information and the accuracy of decision-making. In this paper, we first established an evaluation index system of financial software evaluation, and then combined two-dimensional uncertain linguistic variables (2DULV) and grey relational analysis (GRA) to evaluate and select the financial software. Finally, the effectiveness of the proposed 2DULV-GRA model is verified by an example of an enterprise. The fuzzy evaluation model proposed in this paper allows decision-makers to express uncertainty, which provides a reference for the enterprise decision-making.

I–V traces of strongly emitting emissive probes are investigated in a multidiople filament discharge. It is found that at sufficiently high neutral pressure and emitting current, the variation of the I–V traces and their associated inflection points no longer follow the previous predictions of space charge limited (SCL) models. A new, steep slope region of the I–V trace appears near the plasma potential when the probe is strongly emitting, causing the inflection point and the floating potential to increase towards the plasma potential as emission current increases, rather than staying constant. This is, to our knowledge, the first experimental evidence that the effects predicted by Campanell et al's inverse sheath theory (2017 Physics of Plasmas 24 057101) not only affect the floating potential but also a region in the I–V trace of an emissive probe. It is also found that the double inflection point structure when the probe is biased below the ionization energy of the working gas is highly likely to be an emission retardation effect from enhanced virtual cathode formation due to the increased local electron density. The implications of these findings on hot cathode sources are briefly discussed.

As one of the central cities of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), Shenzhen has excellent air environment performance. Based on the construction of Kaya identity and LMDI method, this paper decomposes the SO2 emission of Shenzhen industry in 2009-2016 and explores the impact of seven factors on the SO2 emission change of Shenzhen, including population, development level, industrial structure, energy structure, energy consumption intensity, energy pollution intensity and end treatment. The results show that: population and development level factors have the effect of increasing emissions, industrial structure and energy structure factors have less impact, while energy consumption intensity, energy pollution intensity and end treatment factors have the obvious effect of reducing emissions. Combined with the current situation of development, it is suggested that Shenzhen should promote the upgrading of industrial structure and energy structure, promote the progress of production technology, and strengthen the end treatment. Other cities in GBA should actively learn from the relevant measures and governance experience taken by Shenzhen to improve the capacity of industrial air pollution reduction.

Transportation cost management plays an important role in both traditional logistics management and supply chain logistics management. Time-driven activity-based costing bypasses the expensive, time-consuming and subjective activity investigation and is more suitable for the intermediate link of enterprise cost accounting. Linear programming is a mathematical theory and method to study the extreme value problem of objective function under linear constraints, and the optimal decision is made by using limited human, material and financial resources. Based on the concept of Shared logistics, this paper studies transport enterprises to solve problems such as information asymmetry in the process of transport. By establishing a linear programming time-driven activity-based costing accounting model, the allocation of scarce resources in transport enterprises can be reasonably solved, and the efficiency of cost accounting can be improved to achieve considerable cost savings.

Strip wrinkling is a kind of recurrent defect in metal production, which leads to the waste of raw material and the decline of production efficiency. The way to reduce loss is to detect this kind of defects as soon as possible. The computer vision algorithms are often used in this kind of situations, but the specific challenge we have to face in this problem is that the steel band is reflective to flash light. This causes the unevenness of exposure in the images we analyze. In order to solve this problem, we propose a method combining homomorphic filtering and region proposal based GBDT algorithm. Our method receives a satisfactory result within both accuracy and detection speed.

Cloud computing environments facilitate applications by providing virtualized resources. It is attracting increasing interests for its elasticity and high quality of service, especially in "big time". For applications, execution time is crucial for the quality of service, because works finished after the deadlines will be useless. Nevertheless, typical cloud environments do not present regular performance in terms of execution and data transmission. And cloud service providers cannot guarantee the performance of execution time, which would take large default risk. In this paper, a performaNce guaranteE Workflow Scheduling (NEWS) algorithm is proposed to address these issues by taking replications based on reconstructed workflow. Characteristics of these issues are summarized to further describe the problems and challenges, which have always been ignored. The algorithm employs the parameter of partial critical path to optimize the workflow scheduling performance. On the analysis of challenges brought up by taking replications, NEWS also optimizes the choice of tasks and the number of replications. Simulation experiments show that the proposed algorithm reduces the variation of total execution time, which makes it possible to provide performance guarantee services.

We propose a new algorithm to solve the quasi-Wigner solution of the gap equation beyond chiral limit. Employing a Gaussian gluon model and rainbow truncation, we find that the quasi-Wigner solution exists in a limited region of current quark mass, $m

Based on the Cahn–Hilliard phase field model, a three-dimensional multiple-field coupling model for simulating the motion characteristics of a rising bubble in a liquid is established in a gas–liquid two-phase flow. The gas–liquid interface motion is simulated by using a phase-field method, and the effect of the electric field intensity on bubble dynamics is studied without electric field, or with vertical electric field or horizontal electric field. Through the coupling effect of electric field and flow field, the deformation of a single rising bubble and the formation of wake vortices under the action of gravity and electric field force are studied in detail. The correctness of the results is verified by mass conservation, and the influences of different electric field directions and different voltages on the movement of bubbles in liquid are considered. The results show that the ratio of the length to axis is proportional to the strength of the electric field when the air bubble is stretched into an ellipsoid along the electric field line under the action of electrostatic gravity and surface tension. In addition, the bubble rising speed is affected by the electric field, the vertical electric field accelerates the bubble rise, and the horizontal direction slows it down.

A coupled lattice Boltzmann and fractal geometry method is introduced to simulate laminar channel flow. The coupled method is divided into two cases. If the height difference between adjacent grids is less than the grid width, the linear interpolation between two points is taken to replace the curve line with the Weierstrass-Mandelbrot (WM) function. If not, the zig-zag line is applied to replace the fractal wall. With a fractal dimension to characterize the shape of the wall, fractal geometry with WM function is adopted to reveal the rough wall. The coupled method overcomes the error of roughness height when adopting fractal function to lattice Boltzmann method. Then, it is concluded that WM function should be used at every grid to ensure the numerical wall is fractal. The coupled method shows its advantage of accuracy with simulations of 2-D laminar channel liquid flows. In addition, the effects of roughness and the boundary slip are taken into consideration. Compared with the experiment data, the proposed method can simulate the real flow accurately. The slip velocity of liquid flow is reduced by the irregular roughness of WM function. Moreover, a comparison between the fractal wall and regular grooves wall indicates that fractal geometry with the WM function is a better way to reveal the real rough wall for laminar flows.

The Er yuan watershed of Er hai district is chosen as the research area, the law of runoff and sediment and non-point source nitrogen and phosphorus discharges under different land uses during 2001 to 2014 are simulated based on SWAT model. Results of simulation indicate that the order of total runoff yield of different land use type from high to low is grassland, paddy fields, dry land. Specifically, the order of surface runoff yield from high to low is paddy fields, dry land, grassland, the order of lateral runoff yield from high to low is paddy fields, dry land, grassland, the order of groundwater runoff yield from high to low is grassland, paddy fields, dry land. The orders of sediment and nitrogen and phosphorus yield per unit area of different land use type are the same, grassland> paddy fields> dry land. It can be seen, nitrogen and phosphorus discharges from paddy fields and dry land are the main sources of agricultural non-point pollution of the irrigated area. Therefore, reasonable field management measures which can decrease the discharge of nitrogen and phosphorus of paddy fields and dry land are the key to agricultural non-point source pollution prevention and control.

The effect of viscosity and viscosity difference and boundary patterned slip on mixing in a micro mixer has been numerically studied using lattice Boltzmann method (LBM). The slip and no-slip ratio is not constant and varies irregularly, and viscosity is altered by changing the relaxation time in LBE equation. The slip boundary condition is simulated by specular reflection boundary and the no-slip boundary condition is simulated by bounce back boundary. It has been found that it is feasible to optimize the micro mixer design by combining the viscosity effect and boundary patterned ratio altogether.

We report combined magnetic susceptibility, dielectric constant, nuclear quadruple resonance (NQR) and zero-field nuclear magnetic resonance (NMR) measurements on single crystals of multiferroics CuBr$_2$. High quality of the sample is demonstrated by the sharp magnetic and magnetic-driven ferroelectric transition at $T_N=T_C\approx$ 74~K. The zero-field $^{79}$Br and $^{81}$Br NMR are resolved below $T_N$. The spin-lattice relaxation rates reveal charge fluctuations when cooled below 60~K. Evidences of an increase of NMR linewidth, a reduction of dielectric constant, and an increase of magnetic susceptibility are also seen at low temperatures. These data suggest an emergent instability which competes with the spiral magnetic ordering and the ferroelectricity. Candidate mechanisms are discussed based on the quasi-one-dimensional (1D) nature of the magnetic system.

We report the synthesis of single crystals of α -ZrSb 2 / α -HfSb 2 and their magneto-transport properties. Both of α -ZrSb 2 and α -HfSb 2 exhibit metallic behavior. The T 3 behavior of zero-field resistivity for both compounds below 30 K indicates interband electron-phonon scattering. The magnetoresistance (MR) is found to obey Kohler's rule for ZrSb 2 while the MR of HfSb 2 deviates from this rule. A possible explanation for the results of Kohler's plot is considered, which is confirmed with the results of the Hall effect. The positive linear Hall resistivity of ZrSb 2 suggests hole-type carriers and a mobility of , while the existence of two types of carriers in HfSb 2 is confirmed from the nonlinear Hall resistivity.

To investigate the convection in a porous medium, a horizontal quiescent layer of one fluid saturating a porous medium heated from bottom is numerically studied using single lattice-Boltzmann method (LBM) and the generalized Navier?Stokes equation proposed by Nithiarasu et al. [P. Nithiarasu, K.M. Seetharamu, and T Sundararajan Int. J. Heat Mass Trans. 40 (1997) 3955]. Due to the rarefaction, the boundary conditions are considered as both temperature jump and velocity slip. The computational results are validated against the analytical results, and excellent agreement has been obtained. The results have shown that the Rayleigh number is increased with increasing temperature jump, the stabilization effect of temperature is much more significant than that of velocity slip, and the computation stability of present model is better than that of Darcy and Brinkman models.

ZnO films are prepared on glass substrates by pulsed laser deposition (PLD) at different oxygen pressures, and the effects of oxygen pressure on the structure and optoelectrical properties of as-grown ZnO films are investigated. The results show that the crystallite size and surface roughness of the films increase, but the carrier concentration and optical energy gap E-g decrease with increasing oxygen pressure. Only UV emission is found in the photoluminescence (PL) spectra of all the samples, and its intensity increases with oxygen pressure. Furthermore, there are marked differences in structure and properties between the films grown at low oxygen pressures (0.003 and 0.2 Pa) and the films grown at high oxygen pressures (24 and 150 Pa), which is confirmed by the fact that the crystallite size and UV emission intensity markedly increase, but the carrier concentration markedly decreases as oxygen pressure increases from 0.2 to 24 Pa. These results show that the crystal quality, including the microstructural quality and stoichiometry proportion, of the prepared ZnO films improves as oxygen pressure increases, particularly from 0.2 to 24 Pa.

Vertically aligned ZnO nanorods were synthesized on a lattice-mismatched cubic-phase Mg0.6Zn0.4O thin-film-coated Si substrate through thermal evaporation of the mixture of carbon and ZnO powders in Ar flow with an atmospheric pressure. X-ray diffraction (XRD) and Raman scattering spectrum results confirmed that the ZnO nanorods have a wurtzite structure. Transmission electron microscopy (TEM), selected-area electron diffraction (SAED) and high-resolution TEM (HRTEM) studies indicated that the nanorods grow along the [0001] orientation. The room-temperature photoluminescence of a strong ultraviolet (UV) emission at 379?nm and a very weak deep-level emission at 510?nm implied the high optical quality of ZnO nanorods. The influence of growth time and substrate temperature on the morphologies of the nanorods was also investigated. It was found that the growth of ZnO nanorods was assisted by thermally induced phase segregation. A possible growth mechanism is proposed.

We state a general principle for seismic migration/inversion processes: think image point coordinates; compute in surface coordinates. This principle allows the natural separation of multiple travel paths of energy from a source to a reflector to a receiver. Further, the Beylkin determinant (Jacobian of transformation between processing parameters and acquisition surface coordinates) is particularly simple in stark contrast to the common-offset Beylkin determinant in standard single arrival Kirchhoff .A feature of this type of processing is that it changes the deconvolution structure of Kirchhoff operators or the deconvolution imaging operator of wave equation migration into convolution operators; that is, division by Green's functions is replaced by multiplications by adjoint Green's functions.This transformation from image point coordinates to surface coordinates is also applied to a recently developed extension of the standard Kirchhoff inversion method. The standard method uses Green's functions in the integration process and tends to produce more imaging artefacts than alternatives, such as methods using Gaussian beam representations of Green's functions in the inversion formula. These methods point to the need for a true-amplitude Kirchhoff technique that uses more general Green's functions: Gaussian beams, true-amplitude one-way Green's functions, or Green's functions from the two-way wave equation. Here, we present a derivation of a true-amplitude Kirchhoff that uses these more general Green's functions. When this inversion is recast as an integral over all sources and receivers, the formula is surprisingly simple.

The pseudopotential method has been used to investigate the structural, electronic and magnetic properties of La1−xEuxGaO3 (x = 0, 0.25, 0.5, 0.75, and 1) within the scheme of generalized gradient approximation. The spin-polarized calculations demonstrate that the ground state is an antiferromagnetic insulator for x ≤ 0.5, while it is ferromagnetic half-metal at x > 0.5. The substitutions of magnetic Eu ions for non-magnetic La ions produce and strength spin polarization, which forcefully urges the system from the insulator to the half metal. Meanwhile, Eu doping strengthens a stoner mechanism for ferromagnetism of La1−xEuxGaO3 (x = 0.75 and 1), which may lead to a rapid increasing in the total magnetic moment and therefore, antiferromagnetic–ferromagnetic transition happens.

We synthesized single crystals of β-MoTe2 by the chemical vapor transport (CVT) method. Resistivity and magnetoresistivity (MR) have been measured. The MR displays H 2 behavior at low field and linear field dependence at high field, which is different from the quadratic behavior in the sample obtained from the NaCl-flux method. It is suggested that the observed linear MR may originate from disorder. The quality and low-temperature property of β-MoTe2 clearly depend on the growth method. Moreover, the angular-dependent MR reveals the two-fold symmetry of Fermi surface.

Generally speaking, the quark propagator is dependent on the quark chemical potential in the dense quantum chromodynamics (QCD). By means of the generating functional method, we prove that the quark propagator actually depends on p4 + iμ from the first principle of QCD. The relation between quark number density and quark condensate is discussed by analyzing their singularities. It is concluded that the quark number density has some singularities at certain μ when T = 0, and the variations of the quark number density as well as the quark condensate are located at the same point. In other words, at a certain μ the quark number density turns to nonzero, while the quark condensate begins to decrease from its vacuum value.

It is commonly accepted that the system undergoes a crossover at high temperature and low chemical potential beyond the chiral limit case, and the properties of the crossover region are important for researchers to understand the nature of strong interacting matters of quantum chromodynamics (QCD). Since at present there is no exact order of parameters of the phase transitions beyond the chiral limit, QCD susceptibilities are widely used as indicators. In this work various susceptibilities are discussed in the framework of Dyson–Schwinger equations. The results show that different kinds of susceptibilities give the same critical end point, which is the bifurcation point of the crossover region and the first order phase transition line of QCD. Nevertheless, different pseudocritical points are found in the temperature axis. We think that defining a critical band is more suitable in the crossover region.

Variational calculations are performed for the ground and first excited states of D0 off centre and the lowest singlet and triplet states of D- off centre in quantum wells in a magnetic field. It is found that the off-centre effect on the binding energies increases with increasing magnetic field. The binding energy of the triplet state can be larger than that of the corresponding singlet one if the magnetic field is strong enough.

A new car-following model is proposed by considering information from a number of preceding vehicles with inter-vehicle communication. A supernetwork architecture is first described, which has two layers: a traffic network and a communication network. The two networks interact with and depend on each other. The error dynamic system around the steady state of the model is theoretically analyzed and some nonjam criteria are derived. A simple control signal is added to the model to analyze the criteria of suppressing traffic jams. The corresponding numerical simulations confirm the correctness of the theoretical analysis. Compared with previous studies concerning coupled map models, the controlled model proposed in this paper is more reasonable and also more effective in the sense that it takes into account the formation of traffic congestion.

A two-dimensional photonic crystal coupled-cavity waveguide is designed and optimized, the transmission spectrum is calculated by using the finite-difference time-domain method, and the group velocity of c/1856 is obtained. To our knowledge, this value of group velocity is the lowest group velocity in a photonic crystal waveguide calculated from its transmission spectrum so far. The result is confirmed by the photonic band structure calculated by using the plane wave expansion method, and it is found that the photonic crystal waveguide modes in a photonic band structure are in accordance with those in the transmission spectrum by using the finite-difference time-domain method. The mechanism of slow light in the coupled-cavity waveguide of photonic crystal is analysed.

We report a molecular dynamics study of crystallization in highly asymmetric binary hard-sphere mixtures, in which the large spheres can form a crystal phase while the small ones remain disordered during the crystallization process of the large spheres. By taking advantage of assisting crystal nucleation with a patterned substrate, direct evidence is presented that there is a close link between the diffusive redistribution of the small spheres and the crystal formation of the large spheres. Although the addition of a second component with large size disparity will not alter the crystal structure formed by the large spheres, the density profile of the small spheres displays corresponding changes at different crystallization stages and closely relates to the crystal growth, suggesting possible effect of small spheres on the crystallization kinetics., Comment: 5 pages, 5 figures