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Science China(information Sciences) 2017年第7期60卷 130-143页

作者： Fushan WEi Jianfeng ma Ruijie ZHAnG Chuangui ma Xuan WAnG State Key Laboratory of integrated Service networks Xidian University State Key Laboratory of mathematical Engineering and Advanced Computing The PLA Information Engineering University Engineering University of CAPF

With the assistance of an authentication server, a gateway-oriented password-authenticated key exchange(GPAKE) protocol can establish a common session key shared between a client and a gateway. Unfortunately, a GPAKE protocol becomes totally insecure if an adversary can compromise the authentication server and steal the passwords of the clients. in order to provide resilience against adversaries who can hack into the authentication server, we propose a threshold GPAKE protocol and then present its security proof in the standard model based on the hardness of the decisional Diffie-Hellman(DDH) problem. in our proposal,the password is shared among n authentication servers and is secure unless the adversary corrupts more than t + 1 servers. Our protocol requires n > 3t servers to work. Compared with existing threshold PAKE protocols,our protocol maintains both stronger security and greater efficiency.

关键词： password key exchange gateway threshold provable security

Timoshenko beam model for chiral materials

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Acta Mechanica Sinica 2018年第3期34卷 549-560页

作者： T.Y.ma Y.n.Wang L.Yuan J.S.Wang Q.H.Qin Department of Mechanics Tianjin University School of Engineering Deakin University Research School of Engineering Australian National University

natural and artificial chiral materials such as deoxyribonucleic acid （DnA）, chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. in this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton＇s principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. it is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DnA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

关键词： Timoshenko beam model Chiral material Chirality Deflection Microrotation

A Comprehensive Approach to investigate CO_(2)Reduction Electrocatalysts at High Current Densities

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Accounts of materials Research 2021年第4期2卷 220-229页

作者： Gastón O.Larrazábal Ming ma Brian Seger Section for Surface Physics and Catalysis(SurfCat) Department of PhysicsTechnical University of Denmark2800 Kgs LyngbyDenmark School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China

As electrochemical CO_(2)reduction studies progress from beaker or H-cell devices operating at low current densities to gas diffusion electrode(GDE)-based devices that sustain high reaction rates and provide an avenue toward commercialization,the overall system becomes significantly more *** the current densities may vary for the different approaches,it is essential to maintain the same scientific rigor when analyzing these *** mass transfer optimizations used in GDE based approaches necessarily add complexity and provide new challenges that need to be analyzed and overcome in terms of both engineering as well as analysis *** Account puts into perspective our recent works analyzing high current density CO_(2)electrolysis performance via a comprehensive investigation of the entire *** particular,we show the importance of monitoring(i)the gas flow rates at the outlet of the cathodic compartment,(ii)the anodic gas composition for CO_(2)/O_(2)ratio,and(iii)pH variations in the electrolyte.A rigorous analysis of these parameters allows us to achieve a complete carbon balance,in addition to accounting for a total of 100%Faradaic *** analyzing both the cathode outlet and anodic CO_(2):O_(2)ratio,we demonstrate that these methods can be used to self-validate results providing *** show that this analysis approach holds for both a zero-gap membrane electrode assembly device and a flowing-catholyte *** addition,a comprehensive monitoring approach reveals that having an alkaline environment in the vicinity of the cathode can absorb substantial amounts of CO_(2),which may greatly distort Faradaic efficiencies if not accounted *** monitoring the outlet flow rate of a reactor appears a simple task,the mixed gases and small flow rates in lab-scale reactors can add challenges and we discuss various methods to measure these flow *** pH is well-known to play a role in the activity and selectivity of CO_(2)redu

关键词： outlet necessarily electrolyte

Rh2O3/hexagonal CePO4 nanocatalysts for n2O decomposition

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Frontiers of Chemical Science and Engineering 2017年第4期11卷 586-593页

作者： Liu, Huan ma, Zhen Fudan Univ Dept Environm Sci & Engn Shanghai Key Lab Atmospher Particle Pollut & Prev Shanghai 200433 Peoples R China

Hexagonal CePO4 nanorods were prepared by a precipitation method and hexagonal CePO4 nanowires were prepared by hydrothermal synthesis at 150 ℃. Rh （nO3）3 was then used as a precursor for the impregnation of Rh203 onto these CePO4 materials. The Rh203 supported on the CePO4 nanowires was much more active for the catalytic decomposition of n20 than the RhzO3 supported on CePO4 nanorods. The stability of both catalysts as a function of time on stream was studied and the influence of the co-feed （CO2, O2, H20 or O2/H20） on the n20 decomposition was also investigated. The samples were characterized by n2 adsorption-desorption, induc- tively coupled plasma optical emission spectroscopy, X- ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, hydrogen temperature-pro- grammed reduction, oxygen temperature-programmed desorption, and CO2 temperature-programmed desorption in order to correlate the physicochemical and catalytic properties.

关键词： Rh2O3 CePO4 n2O decomposition

Porous g-C3n4 with enhanced adsorption and visible-light photocatalytic performance for removing aqueous dyes and tetracycline hydrochloride

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Chinese Journal of Chemical Engineering 2018年第4期26卷 753-760页

作者： Junlei Zhang Zhen ma Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP^3) Department of Environmental Science and Engineering Fudan University Shanghai 200433 China Shanghai institute of Pollution Control and Ecological Security Shanghai 200092 PR China

Porous g-C3n4samples were obtained by simply calcining bulk g-C3n4in static air in a muffle *** photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes（methylene blue and methyl orange）and tetracycline hydrochloride under visible-light irradiation（λ〉420 nm）.Compared to bulk g-C3n4,porous g-C3n4exhibited much better capability for removing these contaminants,especially under visible-light irradiation,due to the enlarged specific surface area and more efficient separation of photogenerated charge *** particular,porous g-C3n4obtained by calcining bulk g-C3n4in air at 525℃ showed the highest visible-light-driven catalytic activity among these *** radical anions（·O2^-）were found to be the primary active species responsible for photodegradation.

关键词： C3n4 Catalyst Reaction Waste treatment Dyes Tetracycline hydrochloride

Water mass characteristics in the western north Pacific based on a streamfunction projection

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Science China Earth Sciences 2015年第11期58卷 2067-2077页

作者： ma Xiao SUn Che institute of Oceanology Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences

A streamfunction projection method called gravest empirical mode(GEM) is applied to the hydrographic section at 137°E to filter out eddy noises in the western north Pacific and derive quantitative ensemble-average water mass properties in the north Equatorial Current region. The GEM fields capture more than 80% of total property variances in the thermocline layer. The core layer structures of key water masses, including the north Pacific Tropical Water(nPTW) and the north Pacific intermediate Water(nPiW), are examined with a definition of water mass boundary based on property gradient. it shows that a tongue of maximal root-mean-square(RMS) residual exists in the upper half of nPiW for all water properties. These subsurface RMS tongues appear to be close to sharp property gradients. it is the first time a GEM diagnosis is applied to nutrient data, which reveals a drastic difference of n/P reaction rate ratio above and below the maximal-nutrient core at 1250 m. Additionally, a GEM velocity reconstruction successfully produces the north Equatorial Undercurrent(nEUC), demonstrating the stable thermal-wind nature of this newly-discovered current.

关键词： streamfunction projection gravest empirical mode water masses western north Pacific

High-Speed Friction Stir Welding of T6-Treated B4Cp/6061Al Composite

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Acta Metallurgica Sinica(English Letters) 2020年第1期33卷 67-74页

作者： Y.Z.Li Y.n.Zan Q.Z.Wang B.L.Xiao Z.Y.ma Key Laboratory of nuclear materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China Shenyang national Laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China University of Science and Technology of China Shenyang 110016China

T6-treated 20 wt% B4 Cp/6061 Al sheets were joined under welding speeds of 400–1200 mm/min by friction stir welding(FSW) with a threaded cermet pin. The macro-defect-free FSW joints could be achieved at high welding speeds up to 1200 mm/min, but larger plunge depth was required at the welding speeds of 800 and 1200 mm/min to eliminate the tunnel defect. in the nugget zone(nZ) of the joints, the B4 C particles were broken up and uniformly redistributed. The nZ exhibited lower hardness than the base metal(BM), and the hardness value almost did not change with increasing welding speed, attributable to the dissolution of precipitates. Compared with the BM, the joints showed lower tensile strength. As the welding speed increased from 400 to 800 mm/min, the joint efficiencies were nearly the same and up to ~ 73%. When the welding speed increased up to 1200 mm/min, the tensile strength significantly decreased, due to the occurrence of kissing bond defect at the bottom of the nZ. With increasing welding speed, the fracture location of the joints transferred gradually from the heat-affected zone to the nZ due to the kissing bond defects.

关键词： Metal-matrix composites Microstructures Mechanical properties Friction stir welding High-speed welding

Rh_2O_3/monoclinic CePO_4 composite catalysts for n_2O decomposition and CO oxidation

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Chinese Journal of Chemical Engineering 2018年第1期26卷 109-115页

作者： Huan Liu Zhen ma Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan University

CePO4 （in particular, monoclinic CePO4） has been rarely used to make supported catalysts. Herein, monoclinic CeP04 nanoparticles were prepared by calcining hexagonal CePO4 nanomds （prepared by precipitation） in air at 900 ℃. Monoclinic CePO4 nanowires were prepared by calcining hexagonal CePO4 nanowires （prepared by hydrothermal synthesis at 150 ℃） in air at 900 ℃. Both monoclinic CePO4 materials were used to support Rh2O3 by impregnation using Rh（nO3）3 as a precursor （followed by calcination）. The catalytic performance of Rh2O3/monoclinic CePO4 composite materials in n2O decomposition and CO oxidation was investigated. it was found that Rh2O3 supported on monoclinic CePO4 nanowims was much more active than Rh2O3 supported on monoclinic CePO4 nanoparticles. The stability of catalysts as a function of reaction time on stream was studied in both reactions. The influence of co-fed CO2, O2, and H2O on the catalytic activity in n20 decomposition was also studied. These catalysts were characterized by employing n2 adsorption-desorption, iCP-OES, XRD, TEM, XPS, H2-TPR, O2-TPD, and CO2-TPD. The correlation between physicochemical properties and catalytic properties was discussed.

关键词： Rh2O3 CePO4 n2O decomposition CO oxidation Catalyst

The Amperometric Glucose Enzyme Electrode by immobilized Glucose Oxidase in Glucose Oxidase/n-ethyl-Poly (4-vinyl)pyridine Multilayer

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Chinese Chemical Letters 1998年第11期9卷 0-0,0页

作者： ma, YZ Heze Teachers Coll Dept Chem Shandong 274015 Peoples R China

Multilayers of glucose oxidase(GOD)/n-ethyl-poly (4-vinyl) pyridine (EPVP) have been assembled on thiol self-assembled monolayers on gold *** electrode can be used as an amperometric enzyme elcctrode for glucose. Fe (Cn)63-/4- incorporated in EPVP layer acts as the electron mediator, the linear range was 0.1 to 6 mmol/L when the number of GOD layers was 5.

关键词： Enzyme electrode glucose oxidase n-ethyl-poly (4-vinyl) pyridine. multilayer.

Deposition of Ti-Si-n coatings in deep blind-hole with pulsed dc power

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中国有色金属学会会刊：英文版 2004年第z1期14卷 260-263页

作者： ma Da-yan ma Sheng-li XU Ke-wei State Key Laboratory for Mechanical Behavior of materials Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of MaterialsXi''an Jiaotong University Xi''an 710049 China

Multiphase nanocomposite Ti-Si-n coatings deposited by pulsed dc plasma enhanced chemical vapor deposition technique on the surface of HSS substrate, which were bolted with deep blind-hole to simulate the complexshaped surface of various tools, were investigated. The micrographs show that the surface morphologies of the coatings become coarser with an increasing depth of the bottom holes. And the silicon content increases in Ti-Si-n coatings, which are composed of nanocrystalline Tin, nano-sized amorphous Si3n4, and occasionally amorphous or nanocrysralline TiSi2. The thickness of the coatings decreases with the increasing depth of holes, which may result from the changes of the composition in the coatings. The microhardness of the coatings increases firstly with the increasing depth of holes, reaches a maximum value of about HV5 700 at 10mm depth, and then decreases at larger depth.

关键词： nanocomposite pulsed dc PCVD Ti-Si-n deep blind-hole