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Green Energy & Environment 2023年第2期8卷 509-518页

作者： Nan Chen Yu Zhou Songtao Cao Ruixin Wang Weizhou Jiao School of Chemical Engineering and Technology North University of ChinaTaiyuanShanxi030051China

The loading strategy of cocatalysts affects its activity exerting and atom utilization.Here,a novel strategy for loading precious metal(Pt)cocatalysts by means of ultrathin N-doped carbon layer is reported.The strategy is based on a pyrolysis process of predesigned N-containing polymers and Pt complexes on hard-template surface,during which Pt can be reduced by carbon from pyrolysis at high temperatures.Finally,the hollow TiO_(2)composite with stable and dispersed Pt on its inner surface was prepared.It shows an ultrahigh photocatalytic H_(2)production activity as high as 25.7 mmol h^(-1)g^(-1)with methanol as sacrificial regent,and displays an apparent quantum yield as 13.2%.The improved photocatalytic activity and stability can be attributed to the highly dispersed and ultrafine Pt nanoparticles,enhanced interaction between Pt-species and carbon support,fast photo-excited electron transport from the high graphitization degree of NC layers,ample oxygen vacancies/defects,as well as the manipulated local charge distribution of Pt/NC-layer configuration.Additionally,the universality of the proposed strategy was demonstrated by replacing metal sources(such as,Ru and Pd).This work presented a promising strategy for the design and development of novel photocatalysts,which shows a broad application prospect.

关键词： Ultrathin carbon layer Ultrafine Pt nanoparticles loading Hollow photocatalyst Photocatalytic hydrogen production

Trans-scale study on the thermal response and initiation of ternary fluoropolymer-matrix reactive materials under shock loading

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Defence Technology（防务技术） 2023年第3期21卷 184-195页

作者： Chao Ge Die Hu Jin Wang Qingbo Yu Haifu Wang Yuanfeng Zheng School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China

To investigate the thermal response and initiation behavior of ternary fluoropolymer-matrix PTFE/Al/W reactive materials,a research combining shock loading tests and trans-scale modelling is conducted.On the basis of a good agreement of the numerically simulated and tested shock wave propagation,the significant impact of component ratios and particle sizes on the evolution of mesoscopic temperature,hot-spots and initiation is well characterized and analyzed.Results demonstrate that as the content of W increases,the range of mesoscopic high-temperature area increases and tends to distribute more uniform,while material with smaller W particles causes more intense particle deformation and larger temperature rise.The time to reach the critical temperature shows positive correlation to the content of W,while the critical temperature of hot-spots shows negative correlation to the particle size of W.For PTFE/Al/W of high density,with the increase of W particle size,the reaction rate decrease,however the time to reach the peak reaction rate shortens.

关键词： deformation shock loading

Source enumeration method by combining diagonal loading and constructing second-order statistics

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中国邮电高校学报：英文版 2023年第1期30卷 47-55页

作者： Wang Chuanchuan Zeng Yonghu Wang Liandong Li Zhipeng State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Luoyang 471003China

A source enumeration method based on diagonal loading of eigenvalues and constructing second-order statistics is proposed,for the case that the antenna array observed signals are overlapped with spatial colored noise,and the number of antennas compared with the number of snapshots meet the requirement of general asymptotic regime.Firstly,the sample covariance matrix of the observed signals is obtained,the eigenvalues of the sample covariance matrix can be acquired by eigenvalue decomposition,and the eigenvalues are diagonally loaded,and a new formula for calculating the diagonal loading is presented.Based on the diagonal loaded eigenvalues,the difference values are calculated for the adjacent eigenvalues after diagonal loading,and the statistical variance of the difference values is calculated.On this basis,the second-order statistics of the difference values are constructed,and when the second-order statistics are minimized,the corresponding number of sources is estimated.The proposed method has wide applicability,which is suitable for both general asymptotic regime and classical asymptotic system,and is suitable for both white Gaussian noise environment and colored noise environment.The method makes up for the lack of source enumeration methods in the case of general asymptotic system and colored noise.

关键词： source enumeration general asymptotic regime colored noise diagonal loading second-order statistics

Deep cover bleeder entry performance and support loading: A case study

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International Journal of Mining Science and Technology 2018年第1期28卷 85-93页

作者： Ted M.Klemetti Mark Alexander Van Dyke Ihsan Berk Tulu Ground Control Branch NIOSHPittsburgh Mining Research Division Mining Engineering Department West Virginia University

Several questions have emerged in relation to deep cover bleeder entry performance and support loading:how well do current modeling procedures calculate the rear abutment extent and loading? Does an improved understanding of the rear abutment extent warrant a change in standing support in bleeder entries? To help answer these questions and to determine the current utilization of standing support in bleeder entries, four bleeder entries at varying distances from the startup room were instrumented,observed, and numerically modeled.This paper details observations made by NIOSH researchers in the bleeder entries of a deep cover longwall panel—specifically data collected from instrumented pumpable cribs, observations of the conditions of the entries, and numerical modeling of the bleeder entries during longwall extraction.The primary focus was on the extent and magnitude of the abutment loading experienced by the standing support.As expected, the instrumentation of the standing supports showed very little loading relative to the capacity of the standing supports—less than 23 Mg load and 2.54 cm convergence.The Flac3D program was used to evaluate these four bleeder entries using previously defined modeling and input parameter estimation procedures.The results indicated only a minor increase in load during the extraction of the longwall panel.The model showed a much greater increase in stress due to the development of the gateroad and bleeder entries, with about 80% of the increase associated with development and 20% with longwall extraction.The Flac3D model showed very good correlation between expected gateroad loading during panel extraction and that expected based on previous studies.The results of this study showed that the rear abutment stress experienced by this bleeder entry design was minimal.The farther away from the startup room, the lower the applied load and smaller the convergence in the entry if all else is held constant.Finally, the numerical modeling method used in this study was capable of replicating t

关键词： Bleeder entry Standing supports Abutment loading Longwall mining Full extraction

loading Localization by Small-Diameter Optical Fiber Sensors

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第2期35卷 275-281页

作者： Liu Rongmei Zhu Lujia Lu Jiyun Liang Dakai College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics College of Civil Aviation Nanjing University of Aeronautics and Astronautics

Structural health monitoring(SHM)in service has attracted increasing attention for years.Load localization on a structure is studied hereby.Two algorithms,i.e.,support vector machine(SVM)method and back propagation neural network(BPNN)algorithm,are proposed to identify the loading positions individually.The feasibility of the suggested methods is evaluated through an experimental program on a carbon fiber reinforced plastic laminate.The experimental tests involve in application of four optical fiber-based sensors for strain measurement at discrete points.The sensors are specially designed fiber Bragg grating(FBG)in small diameter.The small-diameter FBG sensors are arrayed in 2-D on the laminate surface.The testing results indicate that the loading position could be detected by the proposed method.Using SVM method,the 2-D FBG sensors can approximate the loading location with maximum error less than 14 mm.However,the maximum localization error could be limited to about 1 mm by applying the BPNN algorithm.It is mainly because the convergence conditions(mean square error)can be set in advance,while SVM cannot.

关键词： small diameter optical fiber sensor structural health monitoring loading localization back propagation neural network support vector machine

Antigenic Peptide loading into Major Histocompatibility Complex Class I Is Driven by the Substrate N-Terminus

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CCS Chemistry 2022年第3期4卷 910-925页

作者： Mengna Lin Honglin Xu Yi Shi Lin-Tai Da Key Laboratory of System Biomedicine(Ministry of Education) Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghai 200240 Bio-X Institutes Key Laboratory for the Genetics of Developmental and Neuropsychiatric DisordersShanghai Jiao Tong UniversityShanghai 200030

Major histocompatibility complex class I(MHC-I),a key element of the acquired immune system,plays essential roles in activating CD8^(+)T cells by recognizing intracellular antigens derived from pathogens and cancer.Assembly of MHC-I and antigen peptides is critical for the antigen presentation on the cell surface.However,the structural dynamics of antigenic peptide loading into MHC-I,at atomistic resolution,is still elusive.Here,by constructing a Markov state model(MSM)based onlarge scale all-atommolecular dynamics(MDs)simulations with an aggregated simulation time∼24μs,we reveal the detailed molecular mechanism underlying the peptide-loading dynamics into MHC-I and identify the key intermediates with associated thermodynamic/kinetic properties.Furthermore,we examine how the chaperone tapasin-binding protein related(TAPBPR)participates in promoting the peptide loading,and the results show that TAPBPR,by binding to the F pocket,allosterically modulates the structures of the distant pocket B,resulting in formation of a peptide-receptive conformation ideal for accommodating the incoming peptide N-terminus.This study provides fundamental structural insights for the peptide loading into MHC-I in both chaperone uncatalyzed and catalyzed contexts.

关键词： antigenic peptide MHC-I molecule loading molecular dynamics simulations Markov state model

Mechanical properties and failure modes of stratified backfill under triaxial cyclic loading and unloading

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International Journal of Mining Science and Technology 2019年第5期29卷 809-814页

作者： Wang Jie Song Weidong Cao Shuai Tan Yuye School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education Beijing 100083China

Multiple filling of gobs will lead to a layered structure of the backfill.To explore the influence of layering structure on the mechanical properties and failure modes of backfill,different backfill specimens were prepared with a cement/sand ratio of 1:4,a slurry concentration of 75%,and backfilling times of 1,2,3 and 4,separately.Triaxial cyclic loading and unloading experiments were carried out.The results show that with an increase in backfilling time,the peak strength of backfill decreases as a polynomial function and the peak strain increases as an exponential function.The cyclic load enhances the linear characteristic of backfill deformation.The loading and unloading deformation moduli have a linear negative correlation with the backfilling time.The unloading deformation modulus is always slightly higher than the loading deformation modulus.The failure modes of stratified backfill are mainly characterized by conjugate shear failure at the upper layer and tensile failure across the layer plane,and there is usually no damage in the lower layer away from the loading area.

关键词： Stratified backfill Triaxial cyclic loading and unloading Mechanical properties Failure modes Deformation modulus

Numerical analysis of seabed dynamic response in vicinity of mono-pile under wave-current loading

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Water Science and Engineering 2020年第1期13卷 74-82页

作者： Jie Lin Ji-sheng Zhang Ke Sun Xing-lin Wei Ya-kun Guo Key Laboratory of Coastal Disaster and Defence(Hohai University) Ministry of EducationNanjing 210098China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China Faculty of Engineering&Informatics University of BradfordBradford BD71DPUK

Pile foundations have been widely used in offshore engineering.In this study,a three-dimensional numerical model was used to investigate the seabed response around a mono-pile under wave-current loading.Reynolds-averaged Navier-Stokes equations were used to simulate the flow field,and Biot's consolidation equations were used for simulating the response of a porous seabed.The pore water pressure within soil and the effective stress along the depth of the seabed were simulated for various current velocities,with currents traveling either along or against the wave.Results indicate that the current has a significant effect on the effective stress and the pore water pressure distributions,which increases with the current velocity,and that the current traveling against the wave increases the liquefaction depth of the porous seabed.

关键词： Numerical simulation Dynamic response Wave-current loading Mono-pile foundation Porous seabed

Enhanced drug loading efficiency of contact lenses via salt-induced modulation

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Asian Journal of Pharmaceutical Sciences 2019年第2期14卷 204-215页

作者： Qiang Zhu Shirui Mao School of Pharmacy Shenyang Pharmaceutical University

Low drug loading efficiency is one of the main obstacles hindering the application of contact lenses(CLs) as the carrier for extended ocular drug delivery. Here in this study, a simple and effective drug loading method based on salt induced modulation was proposed and demonstrated with mechanism elucidation. First of all, using poly(2-hydroxyethyl methacrylate)(p-HEMA) as the contact lens material, betaxolol hydrochloride, Diclofenac Sodium and Betaxolol Base as the model drugs with different solubility, influence of salt concentration,salt type(sodium salts of sulfate, chloride, and sulfocyanate) and drug properties in the loading solution on drug loading efficiency was investigated. Mechanism of enhanced drug loading in contact lens was further explored via studying the influence of salt on the absorption isotherm, drug solubility and water content of CLs. Applicability of this method to other CLs materials was also investigated. It was demonstrated that adjusting the ionic strength of loading solutions resulted in significant increase of drug loading in CLs. Type and concentration of the salts and solubility of the drug were the main factors influencing enhancement ratio of drug loading. The mechanism for improved drug loading was related to the reduced drug solubility in loading solutions and the reduced bound water content in contact lenses. Modulation of drug loading by adjusting ionic strength was also applicable to other CLs and the light transmittance was not affected. This method was more suitable for salt-form drugs with high solubility. In summary, adjusting ionic strength of loading solution is an economical and effective way to improve drug loading in CLs, and this simple method may also find application in other hydrogel based drug delivery systems.

关键词： Contact lenses Drug loading Ionic strength Absorption isotherms Drug solubility Bound water content

Effect of electrode Pt-loading and cathode flow-field plate type on the degradation of PEMFC

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Journal of Energy Chemistry 2019年第8期28卷 95-103,I0005页

作者： Lijuan Qu Zhiqiang Wang Xiaoqian Guo Wei Song Feng Xie Liang He Zhigang Shao Baolian Yi Fuel Cell System and Engineering Group Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023 Liaoning China University of Chinese Academy of Sciences Beijing 100049 China

The electrode Pt-loading has an effect on the number of active sites and the thickness of catalyst layer,which has huge influence on the mass transfer and water management during dynamic process in PEMFCs. In this study, membrane electrode assemblies with different Pt-loadings were prepared, and PEMFCs were assembled using those membrane electrode assemblies with traditional solid plate and water transport plate as cathode flow-field plates, respectively. The performance and electrochemical surface area of cells were characterized to evaluate the membrane electrode assemblies degradation after rapid currentvariation cycles. Scanning electron microscope and transmission electron microscope were used to investigate the decay of catalyst layers and Pt/C catalyst. With the increase of Pt-loading, the performance degradation of membrane electrode assemblies will be mitigated. But higher Pt-loading means thicker catalyst layer, which leads to a longer pathway of mass transfer, and it may result in carbon material corrosion in membrane electrode assemblies. The decay of Pt/C catalyst in cathode is mainly caused by the corrosion of carbon support, and the degradation of anode Pt/C catalyst is a consequence of migration and aggregation of Pt particles. And using water transport plate is beneficial to alleviating the age of cathode Pt/C catalyst.

关键词： Proton exchange membrane fuel cell Electrode platinum loading Current-variation cycle Traditional solid plate Water transport plate