Analysis of application range of simplified models for field to thermo-field to thermionic emission processes from the cathode

Electron emission plays a dominant role in plasma-cathode interactions and is a key factor in many plasma phenomena and industrial applications.It is necessary to illustrate the various electron emission mechanisms and the corresponding applicable description models to evaluate their impacts on discharge properties.In this study,detailed expressions of the simplified formulas valid for field emission to thermo-field emission to thermionic emission typically used in the numerical simulation are proposed,and the corresponding application ranges are determined in the framework of the Murphy-Good theory,which is commonly regarded as the general model and to be accurate in the full range of conditions of the validity of the theory.Dimensionless parameterization was used to evaluate the emission current density of the Murphy-Good formula,and a deviation factor was defined to obtain the application ranges for different work functions(2.5‒5 eV),cathode temperatures(300‒6000 K),and emitted electric fields(10^(5) to 10^(10) V·m^(-1)).The deviation factor was shown to be a nonmonotonic function of the three parameters.A comparative study of particle number densities in atmospheric gas discharge with a tungsten cathode was performed based on the one-dimensional implicit particle-in-cell(PIC)with the Monte Carlo collision(MCC)method according to the aforementioned application ranges.It was found that small differences in emission current density can lead to variations in the distributions of particle number density due to changes in the collisional environment.This study provides a theoretical basis for selecting emission models for subsequent numerical simulations.

交通工程电子招投标信息化建设方案探究

探讨了交通工程电子招投标信息化建设的关键技术方案,以及其对交通工程建设管理的影响。在建立电子招投标平台的基础上,推进全流程电子化,创新招投标机制,采用统一的开放式数据标准接口,及时公布评标结果,从而提高招投标的效率、透明度和公正性。分析了电子招投标在提高管理效率、加强风险控制和促进公平竞争方面的作用,并展望了电子招投标技术的未来发展趋势以及可持续发展的重要性,以推动交通工程领域的信息化建设,促进交通工程的快速、稳健发展。

Corrosion behavior of electron beam processed AZ91 magnesium alloy

The increasing use of light alloys owing to their high performance makes magnesium alloys very attractive for the use in automotive and biomedical applications.However,it is well known that magnesium and its alloys have poor corrosion resistance in different atmospheric and aqueous environments.As a means of improving corrosion resistance through the microstructure modification,electron beam processing(EBP)was applied on the as-cast AZ91 magnesium alloy.To evaluate the microstructure influence on the corrosion-resistant,the EB processed samples underwent a solution heat treatment and an artificial aging heat treatment.Four different obtained microstructures were investigated by standard microscopy and electrochemical corrosion tests to evaluate the microstructure and its effects on the corrosion resistance of AZ91 alloy.The EBPed specimens show a significant microstructure refinement and homogenous distribution ofβ-phase at the grain boundaries surrounded by supersaturatedα-Mg which acts as a barrier against corrosion.The electrochemical corrosion test of the samples immersed in 3.5 wt%NaCl after 4 weeks indicates that the EBP improves the corrosion resistance of the alloy due to the nobler corrosion potential of supersaturated a-Mg and more stable protective hydroxide films compared to the heat-treated and as-cast conditions.

CPS Modeling of CNC Machine Tool Work Processes Using an Instruction-Domain Based Approach

Building cyber-physical system(CPS) models of machine tools is a key technology for intelligent manufacturing. The massive electronic data from a computer numerical control(CNC) system during the work processes of a CNC machine tool is the main source of the big data on which a CPS model is established. In this work-process model, a method based on instruction domain is applied to analyze the electronic big data, and a quantitative description of the numerical control(NC) processes is built according to the G code of the processes. Utilizing the instruction domain, a work-process CPS model is established on the basis of the accurate, real-time mapping of the manufacturing tasks, resources, and status of the CNC machine tool. Using such models, case studies are conducted on intelligent-machining applications, such as the optimization of NC processing parameters and the health assurance of CNC machine tools.

Effect of de-trapping on carrier transport process in semi-insulating CdZnTe

The effect of de-trapping on the carrier transport process in the CdZ＇nTe detector is studied by laser beam-induced transient current （LBIC） measurement. Trapping time, de-trapping time, and mobility for electrons are determined directly from transient waveforms under various bias voltages. The results suggest that an electric field strengthens the capture and emission effects in trap center, which is associated with field-assisted capture and the Poole-Frenkel effect, respectively. The electron mobility is calculated to be 950 cm2/V-s and the corresponding electron mobility-lifetime product is found to be 1.32 × 10-3 cm2/V by a modified Hecht equation with considering the surface recombination effect. It is concluded that the trapping time and de-trapping time obtained from LBIC measurement provide direct information concerning the transport process.

Nonadiabatic Effect on the Rescattering Trajectories of Electrons in Strong Laser Field Ionization Process

The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.

Investigation of the degradation rate of electron beam processed and friction stir processed biocompatible ZKX50 magnesium alloy

Together with the mechanical properties,the degradation rate is an important factor for biodegradable implants.The ZKX50 Mg alloy is a suitable candidate to be used as a biodegradable implant due to its favorable biocompatibility and mechanical properties.Current research investigates the degradation rate and corrosion behavior of the ZKX50 as a function of the microstructure constituents and their morphology.Since grain refinement is the main strengthening mechanism for the ZKX50,the effect of the microstructure refinement on the corrosion rate was studied by applying electron beam processing(EBP)and friction stir processing(FSP)on the ZKX50 cast alloy.To study the effect of the microstructure constituents and their morphology a subsequent solution heat treatment(HT)was applied to the processed samples.The results show that the EBP and FSP lead to a uniform and remarkably refined microstructure of the ZKX50 alloy and homogeneous distribution of the intermetallic phases.The results of electrochemical corrosion tests together with the microstructure characterization show that microgalvanic corrosion is the predominant mechanism that occurs between the Ca2Mg6Zn3 intermetallic phase andα-Mg matrix.According to the results attained through the electrochemical tests,the EBPed-HT ZKX50 alloy shows higher corrosion resistance compared to all other conditions immersed in 0.5 wt.%NaCl solution.The dissolution and spheroidizing of Ca2Mg6Zn3 particles during the solution heat treatment provides higher corrosion resistance mainly by decreasing the microgalvanic corrosion.The microstructure of the heat-treated samples does not show a significant grain coarsening which can degrade the enhancement of the mechanical properties achieved by the EBP and FSP.

Electron excitation processes in low energy collisions of hydrogen-helium atoms

The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)method.Total and state-selective cross sections have been obtained and compared with the available theoretical and experimental results.The results agree well with available measurements in the overlapping energy regions overall.The comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of channels.The datasets presented in this paper,including the excitation cross sections,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00083.

Laser/Electron Beam Processing of As-cast Nd_2Fe_(14)B Alloy

It was found that the free Fe in the melted zone of the as—cast Nd_2Fe_(14)B alloy could be dissolved by Iaser/electron beam.The growth direction of Nd_2Fe_(14)B grains is nearly perpendicular to the sur- face of the samples.EDX examination showed that Fe element was homogeneously distributed in the melted zone.Results presented in this paper have giv- en hint to remove free Fe in as—cast Nd_2Fe_(14)B alloy.

Activation of Transition Metal(Fe,Co and Ni)-Oxide Nanoclusters by Nitrogen Defects in Carbon Nanotube for Selective CO_(2) Reduction Reaction

The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.

Understanding the Interfacial Energy Structure and Electron Extraction Process in Inverted Organic Solar Cells with Phosphine-Doped Cathode Interlayers

Comprehensive Summary Cathode interlayers(CILs)play an essential role in achieving efficient organic solar cells(OSCs).However,the electronic structure at the electrode/CIL/active layer interfaces and the underlying mechanisms for electron collection remain unclear,which becomes a major obstacle to develop high-performance CILs.Herein,we investigate the relationship of the electron collection abilities of four cross-linked and n-doped CILs(c-NDI:P0,c-NDI:P1,c-NDI:P2,c-NDI:P3)with their electronic structure of space charge region at heterojunction interface.By accurately calculating the depletion region width according to the barrier height,doping density and permittivity,we put forward that the optimal thickness of CIL should be consistent with the depletion region width to realize the minimum energy loss.As a result,the depletion region width is largely reduced from 13 nm to 0.8 nm at the indium tin oxide(ITO)/c-NDI:P0 interface,resulting in a decent PCE of 17.7%for the corresponding inverted OSCs.

Fluorescence Quenching of Anthracene by N,N-Diethylaniline and Phenothiazine in Triton X-100/n-C_(10)H_(21) OH/H_2O Microemulsion

The photo-induced electron transfer reactions of anthracene with N,N -diethylaniline(DEA) and phenothiazine(PTZ) occur in the membrane phase of a Triton X-100/ n -C 10 H 21 OH(1-decanol)/H 2O microemulsion. DEA and PTZ exist in the membrane phase of the microemulsion. Anthracene exists in the oil continuous phase of the W/O microemulsion and in the oil core and membrane phase of the O/W microemulsion.

Real-time digital image stabilization based on regional field image gray projection

Digital image stabilization technique plays important roles in video surveillance and object acquisition.Many useful electronic image stabilization algorithms have been studied.A real-time algorithm is proposed based on field image gray projection which enables the regional odd and even field image to be projected into x and y directions and thus to get the regional gray projection curves in x and y directions,respectively.For the odd field image channel,motion parameters can be estimated via iterative minimum absolute difference based on two successive field image regional gray projection curves.Then motion compensations can be obtained after using the Kalman filter method.Finally,the odd field image is adjusted according to the compensations.In the mean time,motion compensation is applied to the even field image channel with the odd field image gray projection curves of the current frame.By minimizing absolute difference between odd and even field image gray projection curves of the current frame,the inter-field motion parameters can be estimated.Therefore,the even field image can be adjusted by combining the inter-field motion parameters and the odd field compensations.Finally,the stabilized image sequence can be obtained by synthesizing the adjusted odd and even field images.Experimental results show that the proposed algorithm can run in real-time and have a good stabilization performance.In addition,image blurring can be improved.

Charge transfer in low-energy collisions of Be^3+ and B^4+ ions with He

The nonradiative charge-transfer processes of Be3+(1s)/B4+(1s)colliding with He(1s2)are investigated by the quantum-mechanical molecular orbital close-coupling(QMOCC)method from 10 eV/u to 1800 eV/u.Total and state-selective cross sections are obtained and compared with other results available.Although the incident ions have the same number of electrons and collide with the same target,their cross sections are different due to the differences in molecular structure.For Be3+(1s)+He(1s2),only single-electron-capture(SEC)states are important and the total cross sections have a broad maximum around E=150 eV/u.While for B4+(1s)+He(1s2),both the SEC and double-electron-capture(DEC)processes are important,and the total SEC and DEC cross sections decrease rapidly with the energy decreasing.

Atomic process of oxidative etching in monolayer molybdenum disulfide

The microscopic process of oxidative etching of two-dimensional molybdenum disulfide(2D MoS_2) at an atomic scale is investigated using a correlative transmission electron microscope(TEM)-etching study.MoS_2 flakes on graphene TEM grids are precisely tracked and characterized by TEM before and after the oxidative etching. This allows us to determine the structural change with an atomic resolution on the edges of the domains, of well-oriented triangular pits and along the grain boundaries. We observe that the etching mostly starts from the open edges, grain boundaries and pre-existing atomic defects.A zigzag Mo edge is assigned as the dominant termination of the triangular pits, and profound terraces and grooves are observed on the etched edges. Based on the statistical TEM analysis, we reveal possible routes for the kinetics of the oxidative etching in 2D MoS_2, which should also be applicable for other 2D transition metal dichalcogenide materials like MoSe_2 and WS_2.

Enhanced debromination of 4-bromophenol by the UV/sulfite process：Efficiency and mechanism

Halogenated aromatic compounds have attracted increasing concerns due to their toxicity and persistency in the environment, and dehalogenation is one of the promising treatment and detoxification methods. Herein, we systematically studied the debromination efficiency and mechanism of para-bromophenol（4-BP） by a recently developed UV/sulfite process. 4-BP underwent rapid degradation with the kinetics accelerated with the increasing sulfite concentration, pH（6.1–10） and temperature, whereas inhibited by dissolved oxygen and organic solvents. The apparent activation energy was estimated to be 27.8 kJ/mol. The degradation mechanism and pathways of 4-BP were explored by employing N2O and nitrate as the electron scavengers and liquid chromatography/mass spectrometry to identify the intermediates. 4-BP degradation proceeded via at least two pathways including direct photolysis and hydrated electron-induced debromination. The contributions of both pathways were distinguished by quantifying the quantum yields of 4-BP via direct photolysis and hydrated electron production in the system. 4-BP could be readily completely debrominated with all the substituted Br released as Br-, and the degradation pathways were also proposed. This study would shed new light on the efficient dehalogenation of brominated aromatics by using the UV/sulfite process.

Fabrication techniques and applications of flexible graphene-based electronic devices

In recent years, flexible electronic devices have become a hot topic of scientific research. These flexible devices are the basis of flexible circuits, flexible batteries, flexible displays and electronic skins. Graphene-based materials are very promising for flexible electronic devices, due to their high mobility, high elasticity, a tunable band gap, quantum electronic transport and high mechanical strength. In this article, we review the recent progress of the fabrication process and the applications of graphene-based electronic devices, including thermal acoustic devices, thermal rectifiers, graphene-based nanogenerators, pressure sensors and graphene-based light-emitting diodes. In summary, although there are still a lot of challenges needing to be solved, graphene-based materials are very promising for various flexible device applications in the future.

Processing of Calamine with Modern Analytical Techniques:Processed with Huanglian Decoction(黄连汤)and Sanhuang Decoction(三黄汤)

Objective： To determine the pyrolysis characteristics of calcined and processed calamine, qualitatively and quantitatively compare the contents of related elements, morphology and functional groups of the pyrolysis products dried at different heating temperatures and explore the critical temperature and the optimal drying temperature for the process of calamine with Huanglian Decoction（HLD, 黄连汤） and San Huang Decoction（SHD, 三黄汤）. Methods： Pyrolysis products were prepared by programmable and constantly heating the calcined and processed calamine to or at different heating temperatures. Thermogravimetry（TG） was used to test their pyrolysis characteristics. Fourier transform infrared spectroscopy and scanning electron microscopeenergy dispersive spectrometer were used to determine their morphology, functional groups and element contents. Page model was used to investigate the constant drying kinetics of processed calamine. Results： The adding of HLD or SHD to calcined calamine（CC） can slow its weight loss in drying pyrolysis process. The temperature ranges where HLD and SHD can affect its weight loss were 65–150 ℃ and 74–180 ℃, respectively. The drying temperature was optimized as 90 ℃. The drying kinetic for the processed calamine fits Page model shows good linearity. Conclusions： The critical temperature and the optimal drying temperature where HLD and SHD can affect the weight loss rate in the process of calamine were explored using the theories and methods of both biophysical chemistry and processing of Chinese materia medica. This work provides a good example for the study of the process of other Chinese medicines using modern analytical techniques.

Efficient perovskite solar cells based on the novel low-temperature processed electron transport layer

With the support by the National Natural Science Foundation of China,the research team led by Prof.Hou Yu(侯宇)and Prof.Yang Huagui(杨化桂)at the Key Laboratory for Ultrafine Materials of Ministry of Education,School of Materials Science and Engineering,East China University of Science

Electron-transfer fluorescence quenching processes in coaggregates between excited N-alkylcarbazoles as electron donors and 2, 4-dinitrophenyl carboxylates or pentafluorophenyl carboxylates as acceptors

Electron-transfer processes facilitated by hydrophobic-lipophilic interaction (HLI) between excited N-alkylcarbazoles (1-n, n = 4, 8, 12, 16) as electron donors and 2,4-dinitrophenyl carboxylates (2-n, n = 4, 8, 12, 16) or pentafluorophenyl carboxylates (3-n, n = 4, 8, 12, 16) as electron acceptors have been investigated by means of fluorescence spectroscopy in aqueous or aquiorgano binary mixtures. The fluorescence quenching of -n* by 2-n or - n indicates that preassociation precedes the electron transfer. The extent of HLI-driven coaggregation of the acceptor and the donor may be assessed from the B value of the equation I0/I = A + B [Q]. The chain-length effect and possibly also a chain-fold-ability effect, as well as the solvent aggregating power (SAgP) effect have been observed. Comparison of roe quenching constants (B) for 1-n*/2-n combinations and 1-n*/ 3-n combinations shows that the order of increasing B values for the quenching processes is 3-n < 2-n.