Stable multi-electron reaction stimulated by W doping VS_(4)for enhancing magnesium storage performance

Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion batteries.Developing high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of RMBs.Herein,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%W-V-S.The flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction process.The fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction process.Such discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.

Provoking Buying Behaviors Amid Crises:Unfolding the Underlying Mechanisms of Psychological Impairments

Crises in the past have caused devastating,long-lasting impacts on the global economy.The after-effects always bring some dynamic and rigorous challenges for businesses and governments.Such challenges have always been a point of discussion for scholars.The recent COVID-19 pandemic emaciated the global economy,leaving everyone mired in uncertainty,fear,and psychological impairments.One of the headwind features utilized by consumers during pandemic was panic buying(PB),which must be explored in various contexts for policymakers and practitioners.To address this gap,this study deployed a moderated mediation mechanism,integrating the health belief model(HBM)and competitive arousal theory(CAT)to excavate the notions underlying PB with the intrusion of evolved real-time psychological disorders:intolerance of uncertainty(IU)and cyberchondria(CYC).The study was conducted as a natural experiment in a South Asian developing economy using online surveys.It found that health beliefs—perceived severity(PSV)and perceived susceptibility(PSC)—positively impact perceived arousal(PA),which causes PB,and that PA has a sturdy mediator role.Moreover,in the relationship between health beliefs and arousal,the different psychological disorders were found to have significant moderating roles The study findings can help mitigate risk uncertainties and panic situations and thus contribute to consumers’wellbeing.

仿生高取向结构聚乳酸/聚乙二醇/十二烷基硫酸钠熔喷非织造材料的原位牵伸制备及定向导液特性

为增强聚乳酸(PLA)超细纤维非织造材料的液体定向传输能力,选用聚乙二醇(PEG)和十二烷基硫酸钠(SDS)改善PLA的亲水性,并通过原位牵伸辅助的熔喷成型工艺制备了仿生高取向结构PLA/PEG/SDS超细纤维非织造材料,研究了不同牵伸倍率对材料结构与性能的影响。结果表明,PLA/PEG/SDS共混聚合物的玻璃化转变温度为50℃左右,适合进行牵伸;随着牵伸倍率从1.0增加至2.0,高取向度纤维(取向角度≤20°)数量从10%增大至67%,纵向拉伸断裂强力提升151.5%,液体爬升高度从20 mm增大至62 mm。仿生高取向结构PLA/PEG/SDS熔喷非织造材料定向导液特性得到增强,因此满足其在加湿器、雾化器和3D打印机等微流体传输领域的应用。

Manifold Structure Analysis of Tactical Network Traffic Matrix Based on Maximum Variance Unfolding Algorithm

As modern weapons and equipment undergo increasing levels of informatization,intelligence,and networking,the topology and traffic characteristics of battlefield data networks built with tactical data links are becoming progressively complex.In this paper,we employ a traffic matrix to model the tactical data link network.We propose a method that utilizes the Maximum Variance Unfolding(MVU)algorithm to conduct nonlinear dimensionality reduction analysis on high-dimensional open network traffic matrix datasets.This approach introduces novel ideas and methods for future applications,including traffic prediction and anomaly analysis in real battlefield network environments.

Co-MOF as an electron donor for promoting visible-light photoactivities of g-C3N4 nanosheets for CO2 reduction

A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.

Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 expression in early focal cerebral infarction following urokinase thrombolysis in rats

Activity of matrix metalloproteinase-9 increases following cerebral ischemia/reperfusion, and is associated with cerebral microvascular permeability, blood-brain barrier destruction, inflammatory cell infiltration and brain edema. Matrix metalloproteinase-9 also likely participates in thrombolysis. A rat model of middle cerebral artery infarction was established by injecting autologous blood clots into the internal carotid artery. At 3 hours following model induction, urokinase was injected into the caudal vein. Decreased neurological severity score, reduced infarct volume, and increased expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 were observed in the cerebral cortex 24 hours after urokinase thrombolysis. These results suggest that urokinase can suppress damage in the acute-early stage of cerebral infarction.

浸涂法制备聚乳酸乙醇酸共聚物/聚丙烯腹壁复合补片的体外降解及力学性能

现代无张力修补手术是目前治疗疝气最主要的手术方法,该方法采用疝气补片取代局部组织缺损。针对目前腹壁疝气手术中常用的聚丙烯(PP)补片存在的术后不适感及粘连脏器等不足,文中采用浸涂法,将生物相容性优良的聚乳酸乙醇酸共聚物(PLGA)涂覆在PP补片一侧,制备了PLGA/PP腹壁复合补片,研究了其体外降解性能,并与PP补片的力学性能对比。结果表明,PLGA/PP补片有更好的弹性和拉伸性能,相比PP补片,PP/PLGA补片的纵向弹性回复率增加了5.6%,PP/PLGA补片的纵、横向断裂强力和断裂伸长率分别增加了61.79 N,68.49 N和39.5%,24.4%,PLGA先从内部开始降解的特性,有利于避免补片植入前期脏器粘连问题的出现。PLGA/PP补片有望成为一种新型腹壁疝修补片。

Application of Fractal Theory in the Synthesis of Nano-sized 3Y-TZP Superplastic Ceramic Materials

Nano-sized 3Y-TZP powders were Synthesized by two methods. A fractal software was developed. A new and convenient method for characterizing the quality of Synthetic process by using fractal theory was obtained.

Cavitation Behavior during Superplastic Deformation of AZ31 Magnesium Alloy

Superplasticity of AZ31 Mg alloy at the temperature range of 250-450℃ and stain rate range of 0.7×10^-3- 1.4×10^-1s^-1 was examined through uniaxial tensile test.Optical microscopy （OM）and scanning electrom microscopy （SEM）were employed to investigate the morphology of cavities and surface relief near fracture surface,respectively.It is shown that AZ31 Mg alloy starts to exhibit superplasticity for 300℃.The maximum elongation of 362.5% was obtained at 400℃ and strain rate of 0.7×10^-3s^-1,There exist many O-shaped cavities and filaments at the boundaries near fracture surface,The fracture of filaments results in intergranular cavity and the model for the formation of intergranular cavities is proposed .The growth of cavities is plasticity-controlled and the serrated boundaries of intergranular cavities agree with the results of surface relieves.

Microstructural and Microhardness Variation of Amorphous Fe_(78)Si_9B_(13) Alloy during Bend Stress Relaxation

The amorphous Fe78Si9B13 ribbons were bend stress relaxed at various temperature well below the crystallization temperature （Tx） for different time. The effect of pre-annealing on the subsequent bend stress relaxation was examined. The variation of the microstructure and microhardness during bend stress relaxation process was studied using X-ray diffraction （XRD）, atomic force microscopy （AFM） and Vickers microhardness test,respectively. Curvature radius of the amorphous Fe78Si9B13 ribbons decreased with increase bend stress relaxation temperature and time. The microhardness of the stress relaxed specimens increased with time at 300℃ due to the forming of nanocrystals during bend stress relaxation. The pre-annealing reduced the decrease rate of the curvature radius of stress relaxed specimens.

CFD simulation of homogeneous reaction characteristics of dehydration of fructose to HMF in micro-channel reactors

In this work the applicability of the micro-channel reactor technique to the production of promising platform chemical 5-hydroxymethyl furan(HMF) from fructose in aqueous solution is systemically investigated by performing CFD simulations.Influential factors including solvents,residence time distribution of reaction mixtures,heat transfer conditions and micro-channel configurations are evaluated in terms of the reaction performance indices,i.e.,conversion of fructose,HMF selectivity and yield.A scale-up method from a single channel to a multiple channel reactor is also proposed.It is demonstrated that:1) at the single channel scale,controlling residence times and temperature distribution of the reaction mixture within the channel is crucial for enhancing the reaction performance,while different channel configurations lead to marginal improvements;2) for the scaling-up of the reaction process,a reactor module containing 15 circular parallel channels could be used as module blocks,which can be stacked one by one to meet the required reactor performance and production capacity.The present results show that micro-reactors are quite suitable for HMF production.

Efficiency of Land Utilizationand Urbanization Progress of China

Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.

裂缝—孔隙型边底水气藏提高采收率大型物理模拟实验

围绕非均匀水侵导致裂缝—孔隙型气藏采收率低这一共性难题,以典型气藏地质模型为基础,研发大型二维物理模拟模型,建立裂缝—孔隙型气藏大型物理模拟实验方法及其装置,开展了气藏水侵规律及对采收率影响和排采优化提高气藏采收率物理模拟实验,研究了水体倍数、配产高低对气藏水侵规律及采收率的影响,探索了排水时机、排水规模、排水方式等对提高气藏采收率的作用。结果表明:①作用于单井的水体倍数和气井配产高低对水侵前缘推进速度、水侵波及特征以及气藏采收率影响均十分显著,开发过程中应合理部署井网和控制气藏采气速度从而降低水侵伤害程度;②排水时机、排水规模、排水方式等技术措施对提高气藏采收率效果影响显著,应根据气藏实际条件制订合理的优化方案。研究成果对类似气藏制订控水开发提高采收率技术对策具有指导意义。

Simultaneous improving luminescence intensity and stability of CsPbBr_(3):SCN−@Eu/Zr-Uio-66-NH_(2) with tunable emissions from blue to green and applications in indoor photovoltaics

The construction of stable and efficient materials that emit blue and green light remains a challenge.Among the blue light materials reported,metal-organic framework(MOF)materials are rarely reported as blue phosphors due to their weak luminescence intensity.Based on the construction of CsPbBr_(3)@MOF(CPB@MOF),an innovative idea was proposed to simultaneously enhance the green luminescence of CPB and the blue luminescence of MOF through the interaction between CPB and MOF for the first time.As expected,the blue luminescence from CPB:7%SCN−@0.5%MOF:Eu as well as the green luminescence from 5%CPB:7%SCN−@MOF:Eu was sufficient to construct high-performance light-emitting diode(LED)devices and further excite solar cells to generate stable photoelectric signals.The white LED(WLED)device with excellent color quality(color rendering index(CRI)=96.2)and correlated color temperature(CCT=9688 K)can be constructed by using the obtained blue-emitting CPB:7%SCN-@0.5%MOF:Eu,green-emitting 5%CPB:7%SCN−@MOF:Eu,and red-emitting PPB:30%Mn^(2+).The density functional theory(DFT)theoretical calculation results indicate that the p orbital of Pb plays the major role in the conduction band,and the p orbital of Br plays the major role in the valance band of CPB and CPB:SCN−.While the p orbital of O plays the major role in both the conduction band and valance band of MOF.The heat capacity of CPB and CPB:SCN−separately reaches the Dulong–Petit limit at 200 and 400 K,indicating that the thermal stability of CsPbBr_(3)increases after SCN−doping.

Tunable multicolor luminescence in vanadates from yttrium to indium with enhanced luminous efficiency and stability for its application in WLEDs and indoor photovoltaics

The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode(WLED)devices and their application in indoor photovoltaics.Compared with YVO_(4),InVO_(4)is not suitable as the host material of lanthanide ions because of its strong self-luminescence.Here,the work focused on combining the broadband emission from InVO_(4)and the red luminescence from YVO_(4):Eu^(3+)to obtain enhanced and stable multicolor luminescence.The band structure,density of state,and optical properties were studied by density functional theory.The spectral configuration of YVO_(4):In^(3+)/Eu^(3+)with(112)surface appears to be broadening and redshifts with increasing layer number.When the In^(3+)concentration is 3.5 mol%,the YVO_(4):30%Eu^(3+)/In^(3+)emits the strongest light.The Judd-Ofelt parameterΩ2 of YVO_(4):In^(3+)/Eu^(3+)increases with increaing In^(3+)concentration,indicating that the symmetry decreases.By adjusting In^(3+)/Eu^(3+)contents,the YVO_(4):In^(3+)/Eu^(3+)not only can emit white light with a color rendering index of 95,but also can be used as high-efficiency red phosphor to build WLED devices with blue emitting N/Tb codoped carbon quantum dots(CQDs-N:Tb^(3+))and green emitting MOF:Tb^(3+)(MOF=metal organic framework),for which the color rendering index can also reach 95 and the color temperature is 5549 K.The manufactured WLED devices were further used to excite the silicon solar cell and make it show good photoelectric characteristics.

Analysis of the mechanism of orientations evolution during hot rolling and mechanical properties of TiBw/TA15 composites based on crystal plasticity finite element model

An in-depth understanding of the crystal orientation evolution during hot rolling of TiB whisker(TiBw)/TA15 composites and the anisotropy of the as-rolled plates can help fully utilize the material proper-ties.In this paper,the crystal plasticity finite element models of high-temperature(HT)β-phase and room-temperature(RT)α-phase were constructed from electron backscattering diffraction data.Based on this,the orientation evolution during hot rolling in the single-phase region and the effects of the matrix texture on the mechanical properties of the as-rolled plates were analyzed.The effect of TiBw on the anisotropy was studied by the composites finite element model.Results showed that theα-fiber texture of theβ-phase was formed during HT rolling.This texture was converted to the T-texture of theα-phase at RT during cooling according to the Burgers orientation relationships.The TiBw had little effect on the matrix texture composition.The TiBw and matrix texture caused the matrix to have higher strength along the rolling direction and the transverse direction,respectively.The matrix texture dominated the difference in mechanical properties because its effect exceeded that of TiBw.The effect of the matrix on the mechanical properties was caused by the Schmid factors(SFs)and the critical resolved shear stress(CRSS)of the slip system together.The slip mode was influenced by SFs determined by the angular rela-tionship between the crystal orientation and the loading direction.The CRSS of the activated slip system determined the yield strength.

Risk factors in blood for attacks of angina in patients with coronavirus disease 2019 and stable angina

To the Editor:Patients with coronary heart disease(CHD)complicated by coronavirus disease 2019(COVID-19)are at an increased risk of coronary events.Many studies have reported an association between cardiovascular disease and COVID-19.It is also known that patients with COVID-19 have worse outcomes and an increased mortality risk if they have cardiovascular disease.[1]According to a report by the World Health Organization,the estimated COVID-19 mortality rate is about 3.4%overall;however,in patients with cardiovascular disease,this figure increases to 10.5%,which is higher than the death rate in those with underlying diabetes(7.3%)or chronic respiratory diseases(6.3%).

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.

Microstructure and mechanical properties of ultra-fine grained MoNbTaTiV refractory high-entropy alloy fabricated by spark plasma sintering

The MoNbTaTiV refractory high-entropy alloy(RHEA)with ultra-fine grains and homogeneous microstructure was successfully fabricated by mechanical alloying(MA)and spark plasma sintering(SPS).The microstructural evolutions,mechanical properties and strengthening mechanisms of the alloys were systematically investigated.The nanocrystalline mechanically alloyed powders with simple bodycentered cubic(BCC)phase were obtained after 40 h MA process.Afterward,the powders were sintered using SPS in the temperature range from 1500℃to 1700℃.The bulk alloys were consisted of submicron scale BCC matrix and face-centered cubic(FCC)precipitation phases.The bulk alloy sintered at 1600℃had an average grain size of 0.58μm and an FCC precipitation phase of 0.18μm,exhibiting outstanding micro-hardness of 542 HV,compressive yield strength of 2208 MPa,fracture strength of 3238 MPa and acceptable plastic strain of 24.9%at room temperature.The enhanced mechanical properties of the MoNbTaTiV RHEA fabricated by MA and SPS were mainly attributed to the grain boundary strengthening and the interstitial solid solution strengthening.It is expectable that the MA and SPS processes are the promising methods to synthesize ultra-fine grains and homogenous microstructural RHEA with excellent mechanical properties.

The enhanced X-ray Timing and Polarimetry mission—eXTP

In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.