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Phase Transition in a Dense Swarm of Self-Propelled Bots
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作者 Dmitry Bratsun Kirill Kostarev 《Fluid Dynamics & Materials Processing》 EI 2024年第8期1785-1798,共14页
Swarms of self-organizing bots are becoming important elements in various technical systems,which include the control of bacterial cyborgs in biomedical applications,technologies for creating new metamaterials with in... Swarms of self-organizing bots are becoming important elements in various technical systems,which include the control of bacterial cyborgs in biomedical applications,technologies for creating new metamaterials with internal structure,self-assembly processes of complex supramolecular structures in disordered media,etc.In this work,we theoretically study the effect of sudden fluidization of a dense group of bots,each of which is a source of heat and follows a simple algorithm to move in the direction of the gradient of the global temperature field.We show that,under certain conditions,an aggregate of self-propelled bots can fluidize,which leads to a second-order phase transition.The bots’program,which forces them to search for the temperature field maximum,acts as an effective buoyancy force.As a consequence,one can observe a sudden macroscopic circulation of bots from the edge of the group to its center and back again,which resembles classical Rayleigh-Benard thermal convection.In the continuum approximation,we have developed a mathematical model of the phenomenon,which reduces to the equation of a self-gravitating porous disk saturated with an incompressible fluid that generates heat.We derive governing equations in the Darcy-Boussinesq approximation and formulate a nonlinear boundary value problem.An exact solution to the linearized problem for infinitesimal perturbations of the base state is obtained,and the critical values of the control parameter for the onset of the bot circulation are calculated.Then we apply weakly nonlinear analysis using the method of multiple time scales.We found that as the number of bots increases,the swarm exhibits increasingly complex patterns of circulation. 展开更多
关键词 Active matter collective behavior SELF-ORGANIZATION CONVECTION
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Analysis of application range of simplified models for field to thermo-field to thermionic emission processes from the cathode
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作者 Li SUN Zhuo DAI +2 位作者 Ming XU Wei WANG Zengyao LI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第9期51-60,共10页
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 an... 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. 展开更多
关键词 electron emission processes application range Murphy-Good theory implicit particlein-cell Monte Carlo collision method
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Development and assessment of a multifunctional chitosan-based coating applied on AZ31 magnesium alloy: Corrosion resistance and antibacterial performance against Klebsiella Pneumoniae 被引量:2
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作者 Emmanuel Mena-Morcillo Lucien Veleva +3 位作者 Mariana Cerda-Zorrilla Montserrat Soria-Castro Juan C.Castro-Alcátara Rosa C.Canul-Puc 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2021年第6期2133-2144,共12页
This work presents a simple method to functionalise the surface of AZ31 magnesium alloy by applying a duplex MgF_(2)/chitosan coating,which improves its corrosion resistance and provides it with some antibacterial per... This work presents a simple method to functionalise the surface of AZ31 magnesium alloy by applying a duplex MgF_(2)/chitosan coating,which improves its corrosion resistance and provides it with some antibacterial performance.First,the effect of three chitosan solutions with different concentrations on the growth of the bacteria Klebsiella pneumoniae in nutritive medium(TSB)was evaluated by absorbance kinetics experiments,where the chitosan solution at 2%(m/V)was selected for the coating preparation.Before coating application,the AZ31 substrate was pretreated with hydrofluoric acid for 48 hours in order to form a MgF_(2)conversion layer.Subsequently,the coating was applied to the pretreated substrate through the dry-casting method.Samples of the alloy in each surface condition(bare,pretreated,and pretreated+coated with chitosan)were exposed to simulated body fluid(SBF)for 21 days at 37°C,with the solution renewed every 24 hours and the wastes stored.The surfaces were characterised by SEM-EDS,and XPS after the immersion tests,whereas the stored solutions were employed to measure the change in the Mg-ions concentration.Electrochemical impedance spectroscopy and potentiodynamic polarisation were performed in each surface condition to compare their corrosion resistance in SBF.The antibacterial activity of the functionalised surfaces was evaluated by the plate counting method and compared with bare samples.All results were correlated and demonstrate that the modified surface of AZ31 achieved a higher corrosion resistance when it was exposed to SBF,as well as a reduction of the bacterial growth during in vitro tests. 展开更多
关键词 AZ31 Chitosan coating Simulated body fluid Corrosion Antibacterial activity
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Multiatom activation of single-atom electrocatalysts via remote coordination for ultrahigh-rate two-electron oxygen reduction 被引量:3
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作者 Xiaoqing Liu Rui Chen +5 位作者 Wei Peng Lichang Yin De'an Yang Feng Hou Liqun Wang Ji Liang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期622-630,I0015,共10页
Electrocatalytic oxygen reduction via a two-electron pathway(2e^(-)-ORR)is a promising and eco-friendly route for producing hydrogen peroxide(H_(2)O_(2)).Single-atom catalysts(SACs)typically show excellent selectivity... Electrocatalytic oxygen reduction via a two-electron pathway(2e^(-)-ORR)is a promising and eco-friendly route for producing hydrogen peroxide(H_(2)O_(2)).Single-atom catalysts(SACs)typically show excellent selectivity towards 2e^(-)-ORR due to their unique electronic structures and geometrical configurations.The very low density of single-atom active centers,however,often leads to unsatisfactory H_(2)O_(2)yield rate,significantly inhibiting their practical feasibility.Addressing this,we herein introduce fluorine as a secondary doping element into conventional SACs,which does not directly coordinate with the singleatom metal centers but synergize with them in a remote manner.This strategy effectively activates the surrounding carbon atoms and converts them into highly active sites for 2e^(-)-ORR.Consequently,a record-high H_(2)O_(2)yield rate up to 27 mol g^(-1)h^(-1)has been achieved on the Mo–F–C catalyst,with high Faradaic efficiency of 90%.Density functional theory calculations further confirm the very kinetically facile 2e^(-)-ORR over these additional active sites and the superiority of Mo as the single-atom center to others.This strategy thus not only provides a high-performance electrocatalyst for 2e^(-)-ORR but also should shed light on new strategies to significantly increase the active centers number of SACs. 展开更多
关键词 Hydrogen peroxide Oxygen reduction reaction Two-electron pathway Remote coordination ELECTROCATALYSIS
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Assessment of Mg(OH)_(2)/TiO_(2) coating in the Mg-Ca-Zn alloy for improved corrosion resistance and antibacterial performance
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作者 Leonardo Hernández Jesús Ramón-Sierra +4 位作者 Montserrat Soria-Castro Ángel Bacelis Geonel Rodríguez-Gattorno Elizabeth Ortiz-Vázquez Gloria Acosta 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第1期361-378,共18页
The high activity of metallic magnesium and alloys limits its potential in biomedical applications;in recent years,extensive efforts have been devoted to modulating this reactivity.In this work,we present Mg(OH)_(2) a... The high activity of metallic magnesium and alloys limits its potential in biomedical applications;in recent years,extensive efforts have been devoted to modulating this reactivity.In this work,we present Mg(OH)_(2) and TiO_(2)barrier coatings to reduce the degradation of magnesium alloy(Mg-Ca-Zn)surfaces.These coatings were deposited by the anodization method and the spin-coating technique,respectively.The anodized layer was coated with TiO_(2)generated from the hydrolysis of 3%weight of TTIP(Ti[OCH(CH_(3))_(2)]_(4),Titanium(IV)isopropoxide)in 2-Propanol deposited by the spin-coating method.Studying the degradation in Ringer’s solution by electrochemical impedance spectroscopy and OCP revealed a 98%reduction in pittings in uncoated samples after 14 days of immersion.The p H measurements revealed that the TiO_(2)coating reduced the alkalization of the physiological environment,keeping the pH at 6.0 values.In vitro studies of two types of bacteria(E.coli and S.aureus)exhibited zones of inhibition in the agar and activity bactericidal(kill time test).The mechanisms behind the improved degradation resistance and enhanced antibacterial activity are presented and discussed here.Surface modification with Mg(OH)_(2)/TiO_(2)coatings is a promising strategy to control the biodegradation of magnesium implants for bone regeneration. 展开更多
关键词 Magnesium alloy EIS Mg(OH)_(2) TiO_(2) Antibacterial coatings
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Canonical Treatment of Elliptical Motion
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作者 Ola A. Jarab’ah 《Advances in Pure Mathematics》 2023年第9期620-624,共5页
The constrained motion of a particle on an elliptical path is studied using Hamiltonian mechanics through Poisson bracket and Lagrangian mechanics through Euler Lagrange equation using non-natural Lagrangian. We calcu... The constrained motion of a particle on an elliptical path is studied using Hamiltonian mechanics through Poisson bracket and Lagrangian mechanics through Euler Lagrange equation using non-natural Lagrangian. We calculate the generalized momentum p<sub>θ</sub> and we find that this quantity is not conserved and the conjugate θ coordinate is not a cyclic coordinate. 展开更多
关键词 Hamilton Jacobi Equation Generalized Momentum Elliptical Motion Cyclic Coordinate
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Gamma Photon Column Scanning of Prototype and Industrial Distillation Columns
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作者 Witness Chirume Joseph Simpson Dongo +4 位作者 Caven Dzingai Robin Tinavo Mashingaidze Stanford Mudono Rachad Alami Peter Baricholo 《World Journal of Engineering and Technology》 2023年第3期476-492,共17页
Monte Carlo simulation of gamma photon transport and interaction with the distillation column and its contents was performed in order to predict the effects of gamma photons when they interact with matter. The results... Monte Carlo simulation of gamma photon transport and interaction with the distillation column and its contents was performed in order to predict the effects of gamma photons when they interact with matter. The results of the interaction and transport of gamma photons are presented as energy deposition on the distillation column and its contents. Energy attenuation was more pronounced on the column walls and trays as compared to the region between the trays, where there is mostly vapour space. Gamma column scanning was then used to verify the Monte Carlo simulation results by scanning and investigating the integrity of two laboratory prototype distillation and industrial distillation columns. One of the prototype distillation columns was 1 m tall with four trays and the other one was 1.8 m tall consisting of six trays and a packed bed. Commonly encountered distillation column malfunctions such as collapsed tray, weeping, flooding and foaming were simulated in the two prototype distillation columns and scanned. The industrial distillation column was a 26 m tall benzole prefractionator column, consisting of 60 single pass trays and a diameter of 0.8 m. A 10 mCi <sup>60</sup>Co gamma radiation source and NaI(Tl) scintillation detector were used to scan the distillation columns. The results from the two prototypes showed that all the simulated malfunctions were clearly detected except for foaming. The results from industrial distillation column showed that all the trays were in their correct position although tray number 32 could be partially damaged and just below tray 41, the scan revealed that there was a loss of column wall thickness. The obtained density profile for the industrial distillation column showed some small variations from the expected density profile and this was attributed to external features on the distillation column and wind bursts that shifted the source and detector from the chosen scan line orientation. 展开更多
关键词 Gamma Photon Transport Distillation Column Malfunctions Monte Carlo Simulation
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A Variable Separation Approach to Solve the Integrable and Nonintegrable Models:Coherent Structures of the (2 + 1)-Dimensional KdV Eqnation 被引量:8
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作者 TANG Xiao-Yan LOU Sen-Yue 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第7期1-8,共8页
We study the localized coherent structures ofa generally nonintegrable (2+ 1 )-dimensional KdV equation via a variable separation approach. In a special integrable case, the entrance of some arbitrary functions leads ... We study the localized coherent structures ofa generally nonintegrable (2+ 1 )-dimensional KdV equation via a variable separation approach. In a special integrable case, the entrance of some arbitrary functions leads to abundant coherent structures. However, in the general nonintegrable case, an additional condition has to be introduced for these arbitrary functions. Although the additional condition has been introduced into the solutions of the nonintegrable KdV equation, there still exist many interesting solitary wave structures. Especially, the nonintegrable KdV equation possesses the breather-like localized excitations, and the similar static ring soliton solutions as in the integrable case. Furthermor,in the integrable case, the interaction between two travelling ring solitons is elastic, while in the nonintegrable case we cannot find even the single travelling ring soliton solution. 展开更多
关键词 variable SEPARATION approach INTEGRABLE and nonintegrable models (2+1)-dimensional SOLITONS
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Contrasting initial events of localized corrosion on surfaces of 2219-T42 and 6061-T6 aluminum alloys exposed in Caribbean seawater 被引量:7
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作者 Gloria ACOSTA Lucien VELEVA +1 位作者 Juan Luis LóPEZ D.A.LóPEZ-SAURI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第1期34-42,共9页
Aluminum alloy samples, 6061-T6 and 2219-T42, were exposed to Caribbean seawater for 90 d. The fluctuations of open circuit potential, considered as electrochemical noise (EN), were used to characterize and compare in... Aluminum alloy samples, 6061-T6 and 2219-T42, were exposed to Caribbean seawater for 90 d. The fluctuations of open circuit potential, considered as electrochemical noise (EN), were used to characterize and compare initial pitting events, which appeared on their surfaces. EN analysis was carried out using the power spectral density (PSD) vs frequency. The decrease of the β exponent in PSD graphs indicated a release of spontaneous energy with the progress of pit formation in seawater. The fluctuations were associated with the breakdown and formation of new corrosion layers. The values of β exponent in PSD graphs suggest that corrosion process of AA2219-T42 alloy occurs as a persistent non-stationary process, the dynamics of which is controlled by fractional Brownian motion (fBm), while on AA6061-T6 alloy the corrosion process was dominated by stationary and weakly persistent features, with the contribution of fractional Gaussian noise (fGn). After the exposure in seawater, SEM-EDX analysis revealed insoluble intermetallic particles on the alloys, rich in Cu or Fe and irregularly distributed. The preferential dissolution of Mg and Al occurs from the S-phase (Al2CuMg) of AA2219-T42 alloy. 展开更多
关键词 aluminum alloy CORROSION electrochemical noise intermetallic particles seawater
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Degradation of AZ31 and AZ91 magnesium alloys in different physiological media:Effect of surface layer stability on electrochemical behaviour 被引量:3
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作者 Emmanuel Mena-Morcillo Lucien Veleva 《Journal of Magnesium and Alloys》 SCIE EI CAS 2020年第3期667-675,共9页
This work deals with the degradation of AZ31 and AZ91 magnesium alloys when they are exposed to three types of physiological media for seven days at 37°C:Ringer's,Hanks\and simulated body fluid(SBF)solutions.... This work deals with the degradation of AZ31 and AZ91 magnesium alloys when they are exposed to three types of physiological media for seven days at 37°C:Ringer's,Hanks\and simulated body fluid(SBF)solutions.A combination of immersions tests and surface characterisation methods were employed to evaluate the attack on the surface,and the stability of the formed corrosion product layers for each alloy/electrolyte system.Measurements of the Mg-ion released into the electrolytes were also carried out in order to be correlated with the degradation of the alloys.Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarisation(PDP)techniques were employed to compare the performance of the alloys in these different aggressive electrolytes.According to the obtained results,the Mg-alloys exposed to Hanks'media were the less affected,which fact was attributed to a higher stability of the corrosion products layer formed in this medium,in comparison of those formed in Ringer's and SBF solutions.In add让ion,the corrosion damage was lower for AZ91 than for AZ31 alloy in all environments due to its higher Al content.The mass loss rates calculated from both immersion tests and electrochemical methods followed the same trend for comparative purposes between alloys. 展开更多
关键词 Mg-alloys AZ-series Surface layer Physiological media Mass loss rate DEGRADATION
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Photoexcited carrier dynamics in a GaAs photoconductive switch under nJ excitation 被引量:2
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作者 Ming XU Yi WANG +6 位作者 Chun LIU Xinyang SI Rongrong GAO Wei LUO Guanghui QU Wanli JIA Qian LIU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第7期187-193,共7页
In this article,the bunched transport of photoexcited carriers in a GaAs photoconductive semiconductor switch(PCSS)with interdigitated electrodes is investigated under femtosecond laser excitation.Continuous outputs f... In this article,the bunched transport of photoexcited carriers in a GaAs photoconductive semiconductor switch(PCSS)with interdigitated electrodes is investigated under femtosecond laser excitation.Continuous outputs featuring high gain are obtained for single shots and at 1 kHz by varying the optical excitation energy.An ensemble three-valley Monte Carlo simulation is utilized to investigate the transient characteristics and the dynamic process of photoexcited carriers.It demonstrates that the presence of a plasma channel can be attributed to the bunching of high-density electron–hole pairs,which are transported in the form of a highdensity filamentary current.The results provide a picture of the evolution of photoexcited carriers during transient switching.A photoinduced heat effect is analyzed,which reveals the related failure mechanism of GaAs PCSS at various repetition rates. 展开更多
关键词 GaAs PCSS high gain(HG) plasma channel filamentary current heat effect
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Graphitic carbon nitride (g-C3N4)-based nanosized heteroarrays: Promising materials for photoelectrochemical water splitting 被引量:15
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作者 Liqun Wang Wenping Si +6 位作者 Yueyu Tong Feng Hou Daniele Pergolesi Jungang Hou Thomas Lippert Shi Xue Dou Ji Liang 《Carbon Energy》 CAS 2020年第2期223-250,共28页
Photoelectrochemical(PEC)water splitting is recognized as a sustainable strategy for hydrogen generation due to its abundant hydrogen source,utilization of inexhaustible solar energy,high-purity product,and environmen... Photoelectrochemical(PEC)water splitting is recognized as a sustainable strategy for hydrogen generation due to its abundant hydrogen source,utilization of inexhaustible solar energy,high-purity product,and environment-friendly process.To actualize a practical PEC water splitting,it is paramount to develop efficient,stable,safe,and low-cost photoelectrode materials.Recently,graphitic carbon nitride(g-C3N4)has aroused a great interest in the new generation photoelectrode materials because of its unique features,such as suitable band structure for water splitting,a certain range of visible light absorption,nontoxicity,and good stability.Some inherent defects of g-C3N4,however,seriously impair further improvement on PEC performance,including low electronic conductivity,high recombination rate of photogenerated charges,and limited visible light absorption at long wavelength range.Construction of g-C3N4-based nanosized heteroarrays as photoelectrodes has been regarded as a promising strategy to circumvent these inherent limitations and achieve the high-performance PEC water splitting due to the accelerated exciton separation and the reduced combination of photogenerated electrons/holes.Herein,we summarize in detail the latest progress of g-C3N4-based nanosized heteroarrays in PEC water-splitting photoelectrodes.Firstly,the unique advantages of this type of photoelectrodes,including the highly ordered nanoarray architectures and the heterojunctions,are highlighted.Then,different g-C3N4-based nanosized heteroarrays are comprehensively discussed,in terms of their fabrication methods,PEC capacities,and mechanisms,etc.To conclude,the key challenges and possible solutions for future development on g-C3N4-based nanosized heteroarray photoelectrodes are discussed. 展开更多
关键词 graphitic carbon nitride HETEROJUNCTIONS NANOARRAYS photoelectrochemical water splitting
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Time-Dependent Analysis of High-Gain Triggering in Semi-insulating GaAs Photoconductive Switches 被引量:2
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作者 SHI Wei ZHAO Wei +1 位作者 LIANG Zhen-Xian SUN Xiao-Wei 《Chinese Physics Letters》 SCIE CAS CSCD 2001年第11期1479-1480,共2页
The transient transport of photo-generated carriers and temporal variation of the built-in field, during triggering in semi-insulating GaAs photoconductive switches, have been investigated by using a special Monte Car... The transient transport of photo-generated carriers and temporal variation of the built-in field, during triggering in semi-insulating GaAs photoconductive switches, have been investigated by using a special Monte Carlo particle simulator. It shows that the built-in field can exceed the intrinsic avalanche field of semi-insulating GaAs under certain optical and electrical conditions. In such a case, local breakdown ionization is considered to be responsible for the transition in GaAs high-gain switching. The optical and electrical triggering thresholds are calculated and the calculated values of optical and electrical thresholds and partial delay time are in agreement with the published experimental data. 展开更多
关键词 BREAKDOWN OPTICAL ELECTRICAL
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Fiber-Optically Triggered Four Parallel GaAs Photoconductive Semiconductor Switches 被引量:1
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作者 施卫 薜红 +2 位作者 李宁 陈素果 代瑞娟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第6期747-750,共4页
Four parallel GaAs photoconductive semiconductor switches (PCSSs) were triggered simultaneously by four 1064 nm laser beams. The transient characteristics of four linear electrical pulses were investigated. When the... Four parallel GaAs photoconductive semiconductor switches (PCSSs) were triggered simultaneously by four 1064 nm laser beams. The transient characteristics of four linear electrical pulses were investigated. When the energy of four laser beams were 16.4 m J, 15.6 m J, 15.3 m J, and 13.7 m J, respectively, four stable electrical pulses of about 25 ns width and 10 ns rise time were obtained at the same bias voltage of 8 kV. The maximum switching voltage amplitude was 3.8 kV. With the triggering pulse energy and bias voltage kept constant, the three GaAs PCSSs were triggered at 10 Hz laser pulse. The method of synchronization calculation was given, and the synchronization of four parallel GaAs PCSSs was calculated to be 79 ps. The influence of bias voltage and laser energy on the voltage amplitude of electrical pulse was analyzed. Furthermore, relationship between the synchronization and the jitter time was also discussed. 展开更多
关键词 GAAS PCSS FIBER linear mode electrical pulse SYNCHRONIZATION
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Combinatorial synthesis and high-throughput characterization of copper-oxide superconductors 被引量:1
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作者 J Wu A T Bollinger +1 位作者 X He I Bozovic 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期126-129,共4页
Fast synthesis and screening of materials are vital to the advance of materials science and are an essential component of the Materials Genome Initiative. Here we use copper-oxide superconductors as an example to demo... Fast synthesis and screening of materials are vital to the advance of materials science and are an essential component of the Materials Genome Initiative. Here we use copper-oxide superconductors as an example to demonstrate the power of integrating combinatorial molecular beam epitaxy synthesis with high-throughput electric transport measurements. Leveraging this method, we have generated a phase diagram with more than 800 compositions in order to unravel the doping dependence of interface superconductivity. In another application of the same method, we have studied the superconductorto-insulator quantum phase transition with unprecedented accuracy in tuning the chemical doping level. 展开更多
关键词 Materials Genome Initiative combinatorial growth high-throughput characterization copperoxide superconductors
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Velocity Diagnosis of Critical Surface at Microwave Band in Laser-Induced Plasma 被引量:1
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作者 吴莹 王俊彦 +4 位作者 白顺波 陈建平 楚然 恽小华 倪晓武 《Plasma Science and Technology》 SCIE EI CAS CSCD 2008年第4期476-479,共4页
The velocity of critical surface at microwave band in laser-induced plasma was measured and the results are presented. The results indicate that the velocity of critical surface with low electron density is larger tha... The velocity of critical surface at microwave band in laser-induced plasma was measured and the results are presented. The results indicate that the velocity of critical surface with low electron density is larger than that with the high one; and the velocity of critical surface increases with the laser power density. 展开更多
关键词 laser-induced plasma MICROWAVE DIAGNOSIS Doppler effect
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Laser direct writing derived robust carbon nitride films with efficient photon-to-electron conversion for multifunctional photoelectrical applications 被引量:2
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作者 Haotian Tan Wenping Si +7 位作者 Wei Peng Yuqing Wang Daolan Liu Liqun Wang Chongyun Jiang Lu Di Ji Liang Feng Hou 《Carbon Energy》 SCIE CAS 2022年第6期1228-1241,共14页
Carbon nitride,an emerging polymeric semiconductor,has attracted attention in research ranging from photocatalysis to photodetection due to its favorable visible light response and high physicochemical stability.For i... Carbon nitride,an emerging polymeric semiconductor,has attracted attention in research ranging from photocatalysis to photodetection due to its favorable visible light response and high physicochemical stability.For its practical device application,the fabrication of high-quality carbon nitride films on substrates is essential.However,conventional methodologies to achieve high polymerization of carbon nitride are often accompanied by its decomposition,significantly compromising the film quality.Herein,we report an ultrafast fabrication of carbon nitride film by laser direct writing(LDW).The instantaneous high temperature and pressure during LDW can efficiently boost the polymerization of carbon nitride and suppress its decomposition,resulting in high-quality carbon nitride film with excellent mechanical stability with the substrate.Due to the efficient photon-to-electron conversion,it exhibits an outstanding photoelectrochemical water splitting and optoelectronic detection capability,even under strong acid/alkaline conditions.This study thus offers a facile and efficient LDW strategy for the rapid fabrication of carbon nitride film photoelectrodes,demonstrating its great feasibility in multifunctional photoelectrical applications,including but not limited to photoelectrochemical water splitting and optoelectronic detection. 展开更多
关键词 carbon nitride laser direct writing PHOTODETECTORS photoelectrochemical water splitting
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Ion-exchange-induced Bi and K dual-doping of TiOx in molten salts for high-performance electrochemical nitrogen reduction 被引量:1
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作者 Hao Li Liqun Wang +4 位作者 Nan Li Jianmin Feng Feng Hou Sihui Wang Ji Liang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第6期26-34,I0002,共10页
Electrocatalytic nitrogen reduction reaction (e NRR) at the ambient conditions is attractive for ammonia(NH_(3)) synthesis due to its energy-efficient and eco-friendly features. However, the extremely strong N≡N trip... Electrocatalytic nitrogen reduction reaction (e NRR) at the ambient conditions is attractive for ammonia(NH_(3)) synthesis due to its energy-efficient and eco-friendly features. However, the extremely strong N≡N triple-bonds in nitrogen molecules and the competitive hydrogen evolution reaction lead to the unsatisfactory NH_(3) yield and the Faradaic efficiency (FE) of e NRR, making the development of high-performance catalysts with adequate active sites and high selectivity essential for further development of e NRR.Addressing this, we herein report a Bi and K dual-doped titanium oxide (BTO@KTO) material, which is prepared by a cation exchange reaction between K_(2)Ti_(4)O_(5) and molten BiCl_(2), for high-performance e NRR catalysts. Benefiting from the controllable molten-salt cation exchange process, a highly active surface containing Bi/K sites and rich oxygen vacancies has been obtained on titanium oxide. Under the synergy of these two merits, an efficient e NRR catalysis, with the NH_(3) yield rate of 32.02 μg h^(-1)mg_(cat)^(-1) and the FE of 12.71%, has been achieved, much superior to that of pristine K_(2)Ti_(4)O_(9). This work thus offers a highperformance electrocatalyst for e NRR, and more importantly, a versatile cation-exchange strategy for efficiently manipulating materials’ functionalities. 展开更多
关键词 Molten salt ELECTROCATALYSIS Nitrogen fixation Cation exchange Dual doping
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Multi-soliton Solutions of the Konopelchenko-Dubrovsky Equation 被引量:1
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作者 LIN Ji LOU Sen-Yue WANG Ke-Lin 《Chinese Physics Letters》 SCIE CAS CSCD 2001年第9期1173-1175,共3页
By using the standard truncated Painlevé analysis, a Backlund transformation is used to obtain some new types of multi-soliton solutions of the (2+ 1)-dimensional integrable Konopelchenko-Dubrovsky equation from ... By using the standard truncated Painlevé analysis, a Backlund transformation is used to obtain some new types of multi-soliton solutions of the (2+ 1)-dimensional integrable Konopelchenko-Dubrovsky equation from the trivial vacuum solution. 展开更多
关键词 solution. SOLITON TRIVIAL
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Flashover in Back-Triggered Photoconductive Semiconductor Switch 被引量:1
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作者 SHI Wei JIA Ji-Qiang +1 位作者 JI Wei-Li GUI Huai-Meng 《Chinese Physics Letters》 SCIE CAS CSCD 2011年第1期106-108,共3页
Design of a new type of photoconductive semiconductor switches (PCSSs) is presented, and the withstand voltage is improved. The ttashover voltage of the back-triggered PCSS is found to be higher than that of the fro... Design of a new type of photoconductive semiconductor switches (PCSSs) is presented, and the withstand voltage is improved. The ttashover voltage of the back-triggered PCSS is found to be higher than that of the front-triggered one. By analyzing the differences of the flashover voltage between the back-triggered PCSS and the front-triggered PCSS, a detailed statistics analysis and theoretical explanation are expounded. The experiments also prove that the PCSS we developed could resist a voltage as high as 20 k V under the repetition frequency of 30 Hz. 展开更多
关键词 Electronics and devices Optics quantum optics and lasers
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