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This study demonstrates that magnetron-sputtered NbSe2 film can be used as a lubricant for space current-carrying sliding contact, which accommodates both metal-like conductivity and MoS2-like lubricity. Deposition at low pressure and low energy is performed to avoid the generation of the interference phase of NbSe3. The composition, microstructure, and properties of the NbSe2 films are further tailored by controlling the sputtering current. At an appropriate current, the film changed from amorphous to crystalline, maintained a dense structure, and exhibited excellent comprehensive properties. Compared to the currently available electrical contact lubricating materials, the NbSe2 film exhibits a significant advantage under the combined vacuum and current-carrying conditions. The friction coefficient decreases from 0.25 to 0.02, the wear life increases more than seven times, and the electric noise reduces approximately 50%.

The state-of-the-art method generating potential functions used in molecular dynamics is based on machine learning with neural networks, which is critical for molecular dynamics simulation. This method provides an efficient way for fitting multi-variable nonlinear functions, attracting extensive attention in recent years. Generally, the quality of potentials fitted by neural networks is heavily affected by training datasets and the training process and could be ensured by comprehensively verificating the model accuracy. In this study, we obtained the neural network potential of face-centered cubic (FCC) Cu with the most accurate and adequate training datasets from first-principle calculations and the training process performed by Deep Potential Molecular Dynamics (DeePMD). This potential could not only succeed in reproductions of the variety of properties of Cu at 0 K, but also have a good performance at finite temperatures, such as predicting elastic constants and the melting point. Moreover, our potential has a better generalization capacity to predict the grain boundary energy without including extra datasets about grain boundary structures. These results support the applicability of the method under more practical conditions.

BACKGROUND Various non-acquired immunodeficiency syndrome-related diseases, such as cardiovascular disease (CVD), affect the quality of life in people living with HIV (PLWH) and prognosis of acquired immunodeficiency syndrome (AIDS) in the post-active antiretroviral therapy (ART) era. However, little is known about the specific risk ratio between PLWH and HIV-negative individuals. We aimed to incorporate the evidence of HIV-related CVD and explore the risk factors. OBJECTIVE We systematically reviewed the evidence supporting the specific risk of CVD in PLWH. METHODS The PubMed, Embase, Web of Science, and Cochrane Library databases were searched to find cohort and cross-sectional studies that evaluated the risk of hypertension, dyslipidemia, coronary atherosclerosis diseases (CAD), and myocardial infarction (MI) in PLWH. The relative risk (RR), hazard rate (HR), odds ratio (OR), and 95% confidence interval (CI) were calculated for each study, and all were pooled using the random-effects model due to the expected variability among eligible studies. Subgroup and meta-regression analyses were performed to assess for heterogeneity. RESULTS A total of 29 studies that met the inclusion criteria were analyzed, which included 300,274 HIV-positive and 39,256,498 HIV-negative individuals. Compared with people without HIV, PLWH were associated with a higher risk of hypertension (HR = 1.28, 95% CI: 1.03–1.58), dyslipidemia (HR = 1.64, 95% CI: 1.38–1.94), CAD (HR = 1.37, 95% CI: 1.24–1.51), and MI (HR = 1.48, 95% CI: 1.28–1.72). Age, gender, body mass index (BMI) , region, smoking and time to initiate therapy had an impact on the risk of CVDs in PLWH. With aging, the pooled risk of hypertension and dyslipidemia slightly increased, while CAD decreased. Men with AIDS generally have a higher risk of hypertention(HR = 1.27, 95% CI: 1.01–1.61) and dyslipidemia(HR = 1.86, 95% CI: 1.56–2.22). A high BMI (obese/overweight) evidently increased the risk of dyslipidemia in PLWH (HR = 2.53, 95% CI: 1.43–4.47). The risks significantly varied in different regions, but PLWH generally had a higher risk of developing CVDs, especially hypertension and hyperlipidemia. And smoking explicitly related to the increased risk of most CVDs, except for hypertension. The earlier initiation of ART helps to decrease the risk of CVDs in PLWH. Significant heterogeneity was observed across studies for all outcomes analyzed (I2> 70%, P < 0.001), which was only partly explained by the available study-level characteristics. CONCLUSIONS The risk of CVD in PLWH is higher than that in the general population. Different targeted prevention strategies for CVD should be adopted according to the risk characteristics of PLWH of different ages in different regions. The HR of CVD in the post-ART era is relatively reduced, while the risk of dyslipidemia, CAD, and MI increases slightly with smoking. For dyslipidemia in PLWH, the risk increased in men and in people with a high BMI.

The stochastic function describing the stochastic behavior of traffic flow in the process of acceleration or deceleration can better capture the stochastic characteristics of traffic flow. Based on this, we introduce the stochastic function into a high-order viscous continuous traffic flow model and propose a stochastic traffic flow model. Furthermore, we performed the bifurcation analysis of traffic flow system based on the model. Accordingly, the traffic flow problem is transformed into the stability analysis problem of the system, highlighting the unstable traffic characteristics such as congestion. The model can be used to study the nonlinear dynamic behavior of traffic flow. Based on this model, the existence of Hopf bifurcation and the saddle-node bifurcation is theoretically proved. And the type of the Hopf bifurcation is theoretically derived. The model can also be used to study the mutation behavior of system stability at bifurcation point. From the density space-time diagram of the system, we find that the system undergoes a stability mutation when it passes through the bifurcation point, which is consistent with the theoretical analysis results.

The essence of traffic congestion is a kind of bifurcation behavior incurred by the loss of stability in the traffic flow from the perspective of system stability. Therefore, researching the bifurcation characteristics of traffic flow can provide some new methods for relieving the traffic congestion. In this paper, we study the bifurcation dynamic behavior and the bifurcation conditions of traffic flow based on Kühne’s continuum traffic flow model. We discussed the types and stabilities of the equilibrium solutions and proved the existence conditions of some bifurcation of the model. Then various bifurcations of the system are found by numerical simulation and the stability catastrophic behaviors initiated by some bifurcation in traffic flow are investigated. Combined with the measured data, we study the actual traffic flow bifurcation phenomena and analyze the internal reasons for the stability catastrophic behavior of traffic flow passed by the bifurcation point. The nonlinear characteristics and formation mechanism of traffic flow phenomena are revealed from a new perspective. It may help to design the corresponding control schemes for preventing and alleviating traffic congestion.

A modified continuum traffic flow model is established in this paper based on an extended car-following model considering driver’s reaction time and distance. The linear stability of the model and the Korteweg–de Vries (KdV) equation describing the density wave of traffic flow in the metastable region are obtained. In the new model, the relaxation term and the dissipation term exist at the same time, thus the type and stability of equilibrium solution of the model can be analyzed on the phase plane. Based on the equilibrium point, the bifurcation analysis of the model is carried out, and the existence of Hopf bifurcation and saddle-node bifurcation is proved. Numerical simulations show that the model can describe the complex nonlinear dynamic phenomena observed in freeway traffic, such as local cluster effect. Various bifurcations of the model, such as Hopf bifurcation, saddle-node bifurcation, Limit Point bifurcation of cycles, Cusp bifurcation and Bogdanov–Takens bifurcation, are also obtained by numerical simulations, and the traffic behaviors of some bifurcations are studied. The results show that the numerical solution is consistent with the analytical solution. Consequently, some nonlinear traffic phenomena can be analyzed and predicted from the perspective of global stability.

Based on the chemical reaction model proposed by Park, the ‘blackout’ of a reentry vehicle is studied in this paper. The temperature, pressure and electron density distribution characteristics around the reentry vehicle were simulated at various flight speeds and altitudes by USim. Subsequently, the scattering matrix method was used to study the transmission characteristics of terahertz waves in ‘blackout’. The simulation results show that the temperature around the aircraft is mainly affected by speed, the pressure is mainly affected by the altitude and electron density is affected by both of these factors. The calculation results show that the transmission characteristics of terahertz waves in plasma are mainly affected by electron density, while the effects of temperature and pressure cannot be ignored either.

Potential allergenicity of amandin was reduced by binding amandin with (-)-epigallocatechin gallate (EGCG) via alkaline, free radical, ultrasound-assisted alkaline, and ultrasound-assisted free radical methods. These results of total phenol content, free sulfhydryl group, free amino group, surface hydrophobicity, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicated that amandin might be covalently bound to EGCG through reactive groups such as sulfhydryl and amino groups, or non-covalently through hydrophobic interactions. Fourier transformed infrared (FT-IR) spectroscopy and fluorescence spectroscopy revealed structural changes of amandin-EGCG conjugate, which also caused significant reduction in potential allergenicity of amandin. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) found that amandin bound to EGCG mainly through cysteine and glutamate residues, and linear epitope for amandin was reduced. This provided a new method and theoretical basis of hypoallergenic almond food.

We aimed to assess the effect of second-line anti-TB treatment and determine which drugs can achieve the greatest clinical benefit for DR-TB-HIV patients by comparing multiple chemotherapy regimens, to provide a basis for evidence-based practice.We searched three electronic databases (PubMed, Web of Science and Cochrane) for related English studies published since 2010. A random-effect model was used to estimate the pooled result for the treatment outcomes. Subgroup analysis based on possible factors, such as ART, baseline CD4 T-cell count, treatment regimens, and profiles of drug resistance, was also conducted to assess factors for favorable outcome. Outcomes were treatment success and mortality.38 studies, 40 cohorts with 9279 patients were included. The pooled treatment success, mortality, treatment failure, and default rates were 57.5 % (95 % CI 53.1-61.9), 21 % (95 % CI 17.8-24.6), 4.8 % (95 % CI 3.5-6.5), and 10.7 % (95 % CI 8.7-13.1), respectively, in patients with DR-TB and HIV co-infection. Subgroup analysis showed that BDQ and LZD based regimen, and ≥ 2 Group A drugs were associated with a higher treatment success rate. Besides, higher CD4 T-cell count at baseline was also correlated with higher treatment success rate, too.Suboptimal anti-TB outcomes underlining the need to expand the application of effective drugs and better regimen in high HIV setting. BDQ and LZD based all-oral regimen and early ART could contribute to higher treatment success, particularly among XDR-TB-HIV patients. Given that all included studies were observational, our findings emphasize the need for high-quality studies to further investigate the optimal treatment regimen for DR-TB-HIV.

A magnetized cylindrical target composed of a gold tube filled with deuterium-tritium fuel plasma at low density is studied numerically in the present paper. A shock wave is produced when a heavy ion beam heats the gold along the direction of the magnetic field. The density peak of the shock wave increases with the increase in time and it propagates in the −r direction in the cylindrical tube. It seems that this wave is the supermagnetosonic wave. It is found that the Mach number M is between 6.96 and 19.19. The density peak of the shock wave increases as the intensity of the heavy ion beam increases. Furthermore, the density peak of the shock wave increases as the external magnetic field increases.

VC nanocomposite coatings with high carbon content were deposited by multi-arc ion plating at varied substrate bias voltages ranging from − 50 to − 250 V. There is a comprehensive study as to coating preparation and corresponding microstructure, phase contents and their relationship with mechanical properties. The results show that carbon bonding is significantly affected by bias voltage. For the coatings deposited at high bias voltage, the appropriate combination of inducing compressive stress and manipulating the nanostructure accounts for the effect of hardening and toughening. The tribological and corrosive responses of nanocomposite VC coatings are implemented in the condition of seawater. The hard yet tough nanocomposite structure makes the coatings have favorable wear resistance. Moreover, the smooth surface and dense structure obtained at high bias voltage jointly improve capacity of anti-corrosion resistance. The results are beneficial to the potential application of VC nanocomposite coating in seawater.

The electromagnetic pulse excited by the collision between a hypervelocity meteoroid and a spacecraft is studied both numerically and theoretically. It is found that there are two kinds of electromagnetic pulse. The high-frequency electromagnetic pulse may be excited by the sum of all the electric dipoles. Each electron can be considered as an electric dipole. The low-frequency electromagnetic pulse is produced by the Langmuir oscillation of electrons. The energy flux density and the duration time of the excited low-frequency electromagnetic pulse by the meteoroid are also studied in the present paper. It is shown that the energy flux density increases as either the impact speed or the mass of the meteoroid increases. It is also shown that the duration time decreases as both the impact speed and the mass of the meteoroid increase. By measuring the strength and the duration time of the electromagnetic pulse excited by the collision between the hypervelocity meteoroid and spacecraft, we can estimate the speed and the mass of the hypervelocity meteoroid, which will be helpful in space flight and space exploration.

The electron dynamics and the Thomson backscattering of an electron moving in a combined field of a tightly focused Gaussian laser pulse and an external uniform magnetic field are investigated in detail. It is found that by considering the tightly focused Gaussian laser pulse, the electron can be pushed out from the laser pulse by the ponderomotive force, resulting in the symmetry breaking of the electron dynamics from the Gaussian envelope, which can dramatically enhance the radiation intensity. It is also found that by introducing an external magnetic field, the emergence of the cyclotron motion of the electron under the external magnetic field also breaks the symmetry of the electron dynamics and enhances the radiation. Especially in the resonance case, i.e., the cyclotron frequency of the electron is close to the laser frequency, the emission spectrum is further enhanced due to the great extension of the interaction time and the symmetry breaking by the beat wave between the helix motion and the cyclotron motion of the electron in the combined field, and a platform with high radiation intensity containing the THz band has also appeared.

In order to further improve the functional properties of egg white protein powder (EWP), the effects of ball-milling pretreatment on the functional properties of EWP by glycosylation modification were studied. The results manifested that glycosylation reaction was successful. Compared with CEWP (glycosylated egg white protein powder without ball-milling pretreatment), BCEWP (glycosylated egg white protein powder after ball-milling pretreatment) showed lower free amino acid content and higher solubility. The results indicated that ball-milling pretreatment changed the secondary and tertiary structures of protein then prominently enhanced the degree of glycosylation reaction of EWP. Foaming ability of BCEWP (203.3%) was 1.12 times higher than that of CEWP (182.2%). The water holding capacity (WHC) of BCEWP (104.77%) was significantly larger than that of CEWP (100.28%), besides, BCEWP had greater gel springiness than CEWP. These results confirmed that ball-milling was an effective pretreatment to enhance the foaming and gel properties of EWP by glycosylation modification.

By using the particle-in-cell (PIC) simulation method, we studied how the proton beam is confined in a bent magnetic mirror. It is found that the loss rate of the charged particles in a bent mirror is less than that in the axi-symmetric mirror. For a special bent mirror with the deflection angle of the coils α = 45°, it is found that the loss rate reaches maximum value at certain ion number density where the ion electrostatic oscillation frequency is equal to the ion cyclotron frequency. In addition, the loss rate is irrelevant to the direction of the proton beam. Our results may be helpful to devise a mirror. In order to obtain the least loss rate, we may choose an appropriate deflection angle, and have to avoid a certain ion number density at which the ion electrostatic oscillation frequency is equal to the ion cyclotron frequency.

Egg white is often used in various food products because of its good functional properties such as gelling, foaming and emulsifying. In this article, heat treatment（30, 40, 50, 60 °C, 10 min）was employed to investigate the effects on the functional, physicochemical and molecular properties of thick egg white (KEW) comprehensively. The heat treatment caused the hardness, springiness, viscosity, and particle size of KEW to decrease and then increase. According to the results of surface hydrophobicity, sulfhydryl content and fluorescence spectroscopy, the protein structure expanded and then further aggregated after heat treatment with the exposure of the reactive group. The solubility, foaming capacity and emulsifying capacity of KEW were improved by heat treatment. The result of Fourier transformed infrared spectroscopy (FT-IR) showed that the heat treatment changed the structure of KEW from ordered to disordered. The heat treatment did not change the protein composition of KEW based on SDS-PAGE.

Cr C nanocomposite coatings were deposited by multi-arc ion plating with various argon/acetylene mixtures. The XRD, XPS and HRTEM characterization suggest that the coatings consist of a carbide phase and an amorphous carbon-rich phase. The carbide phase is shown to be CrC with a fcc NaCl (B1) structure. Experiment findings and theoretical calculations reveal phase segregation of sp2-carbon from carbides in which the excess amounts of carbon are incorporated. Nanoindentation, scratch test and Rockwell indentation were performed to investigate the toughness and adhesion ability. A significant improvement of adhesion and toughness is achieved by increasing C content at the expense of hardness. The wear resistance of Cr C coatings is controlled by the friction rather than hardness. Compared to dry friction, lower friction coefficients but higher wear rates were obtained under seawater condition. The corrosion behavior of Cr C nanocomposite coatings with different C % was determined by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The coatings with higher Cr content display excellent anti-corrosion properties in seawater.

The inhomogeneity is introduced by a nonzero density gradient which separates the plasma into two different regions where plasma density are constant. The Alfvén waves, the phase mixing and the fast magnetosonic wave are excited by the boundary condition in inhomogeneous magnetized plasma. By using the Hall–magnetohydrodynamics (MHD) model, it is found that there are Alfvén waves in the homogeneous regions, while the phase mixing appears in the inhomogeneous region. The interesting result is that a fast magnetosonic wave is excited in a different direction which has a nonzero angle between the wave propagation direction and the direction of the background magnetic field. The dependence of the propagation direction of the excited fast magnetosonic wave and its strength of the magnetic field on the plasma parameters are given numerically. The results show that increasing both the driving frequency and the ratio of magnetic pressure to thermal pressure will increase the acceleration of the electrons. The electron acceleration also depends on the inhomogeneity parameters.

By performing modulational instability analysis of the the nonlinear coupled dimensionless equations between a fast magnetosonic wave (FMSW) propagating obliquely with the magnetic field and a low-frequency slow Alfvén wave (SAW), we obtain the dispersion relation of the perturbation wave. The growth rate of the perturbation wave is obtained. It is found that the growth rate increases as background magnetic field increases, which is in agreement with that reported by Tiwary et al (2016 Phys. Plasmas 23 122307). A critical perturbation wave number is found. When the perturbation wave number is greater than or equal to the critical value, the growth rate is positive and it increases as the perturbation wave number increases, while the wave is stable. The maximum growth rate is reached when the frequency of the FMSW is half of the ion cyclotron frequency. The minimum growth rate is reached when the propagation direction of the perturbation wave is the same as that of the FMSW.

The propagation characteristics of electromagnetic (EM) waves in dusty plasma of rocket exhaust are studied. Usually, the dust sizes are different in a general dusty plasma. However, most previous studies have focused on the mono-sized dusty plasma. The influence of dust size distribution on the EM wave attenuation of dusty plasmas has been investigated. The dependence of the EM wave attenuation on the electron density of dusty plasmas, the neutral gas density and the EM wave frequency are obtained and discussed. The results illustrate that the EM wave attenuation constant has a maximum value when the electron-neutral particles collision frequency is close to the EM wave frequency. The EM wave attenuation constant increase with the increase of electron density and dust particles density. Moreover, the EM wave attenuation constant decreases as the dust size decrease for mono-sized dust particles. It indicates that the attenuation of the EM wave is mainly determined by the largest dust particles. Finally, we conclude that the larger the dust particle, the stronger the attenuation to the EM wave.

In this work, the structure, elastic, and electronic properties of the recently synthesized MAX phase Lu 2SnC under pressure were studied by the first-principle calculation. The effect of high pressures, up to 20 GPa, on the structure shows that the compressibility along the a-axis was higher than that along the c-axis, which indicates that the Lu–C bonds are more resistant than Lu–Sn bonds. Meanwhile, we derived the elastic modulus (B, G, Y), Pugh’s ratio ( G / B), Poisson’s ratio ( ν), and averaged compressibility ( β). The value of bulk moduli, Young’s moduli, and shear moduli increases under pressure, which means that the pressure can enhance the ability of resisting to shape change and improve the stiffness and hardness of Lu 2SnC. Poisson’s ratio change from 0.184 to 0.246 in the 0–20 Gpa pressure range, which means that Lu 2SnC is brittle in nature, this result is consistent with that obtained from the Cauchy pressure and Pugh’s ratio. In addition, we calculated the shear anisotropy factor ( A), A i (i = 1,2,3), A B, and A G. We found that the elastic anisotropy increases with increasing pressure. Finally, the electronic properties of Lu 2SnC were calculated. As the pressure increases, a pseudo-gap appears in the energy range of − 2 eV to − 3 eV. The total density of state at the Fermi level remains virtually unchanged with the increasing pressure. We hope that our study can complement the future experimental and theoretical work, which can lead to further insights.

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First principles calculations have been performed to investigate the synergetic effect of H and He impurities with vacancies in Ti3AlC2. The configurations and energetics of Hn-He-VAl complexes (n ≤ 4) and He-He/He-H/H-H interactions have been studied. It is found that the impurity H atom prefers to occupy the tetrahedral interstitial site (Itetr-3), but the He atom prefers to occupy the octahedral interstitial site (Ioct-4) in perfect Ti3AlC2. Within a pre-existing Al vacancy, the most favorable site for a He atom is close to tetr-site, meanwhile the H atom preferentially deviates from the vacancy center with the separation 1.3 Å along the 001 direction. He-H and He-He show a weakly attractive interaction, but weak repulsion occurs in the H-H interaction, which is different from the case of Ti3SiC2. The He-VAl complex plays an important role in the trapping of H atoms. The He-VAl cluster can trap up to three H atoms in the absence of H2 molecules, which leads to the formation of a H-He hybridized bubble. Thus, the He atom can subsequently suppress further aggregation of H atoms and block hydrogen embrittlement and volume swelling.

The light intensity distribution at the output image plane is calculated, which is based on the partially coherent light imaging theory, for analysing the imaging system of Foucault's knife-edge test. Theoretical results indicate that information about the phase change of the input object can be obtained for given conditions and illumination by an incoherent or partially coherent source. This theoretical result, under the approximation of incident coherent light, is the same as that of the general coherent diffraction theory. Moreover, an imaging device for real-time observation of the information on the phase contrast of objects is proposed. As an example, a holographic grating that has been bleached as an input object is observed, and its optical parameters are measured directly. Experimental mechanisms with regard to the image-forming process are discussed, which agree with theoretical analysis.

A real-time white light stereo pseudocolor encoding method and technique in a microscope is presented, which demonstrated that the phase information of an object is not totally lost in incoherent imaging. The image system is an improved microscope and attached optical elements can be stacked together in the microscope tube, so the structure is compact. The irradiance distribution at the output plane of the microscope is obtained by means of the theory of partially coherent light. At the conditions of that the aperture stop and focal length of condenser are a right magnitude, and the illuminative light source is incoherent or partially coherent, the theoretical analysis indicates that the irradiance distribution at output plane is presented by the stereo pseudocolor image which is characterized by the phase rate-of-change function of input object. A bleached holographic grating as an input object is observed, and its optical parameters are measured directly. Experimental results are discussed, which basica...

Transmission and reflection of a soliton in an inhomogeneous plasma are investigated. Both the transmission and the reflection can be described by the KdV (Korteweg-de Vries) equations for the discontinuous case. The numbers and magnitudes for transmitted and reflected solitons are analytically given. The transmission can be described by the KdV-type equation for continuous varying inhomogeneous plasma, and the quasi-solitons is also analytically given.

A real-time white light stereo pseudocolor encoding technique for the phase rate-of-change in the imaging system of microscope is presented. It is analyzed by the theory of partially coherent light. The analytic results showed that the information about phase rate-of-change of the input object function is reflected in the output stereo pseudocolor image under given conditions and illuminated by incoherent source.

The propagation and the refraction of shock wave in one‐dimensional lattice are investigated by molecular dynamics (MD). Far from the piston, the distribution of velocity near every pick agrees with related solitary wave solutions, which are obtained exactly for Toda lattice and approximately for other potentials. Dependence of wave velocity on particle velocity also agrees with corresponding relations for solitons. By using averaging parameters to describe interaction between molecules of different matters, the refraction of shock wave is calculated that shows not only qualitative but also quantitative agreement of MD calculation with results of macroscopic continuum mechanics.