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Enamel matrix proteins in promoting saliva lubrication

Friction 2024年第10期12卷 2298-2312页

作者： Hujun WANG yue TANG Haonan qiu Jingyang HU Yuan SU Jing zheng Zhongrong ZHOU Tribology Research Institute School of Mechanical Engineering and Key Laboratory of Advanced Technologies of Materials(Ministry of Education)Southwest Jiaotong UniversityChengdu 610031China

Anti-wear performance of human enamel in the mouth is closely related to the lubrication of salivary *** is well known that the inorganic hydroxyapatite(HA)of the enamel plays an important role in the adsorption and pellicle-forming of salivary proteins on the enamel,but the role of enamel matrix proteins remains *** this study,the adsorption and lubrication behavior of salivary proteins on original,heated,and deproteinated enamel surfaces was comparatively investigated using an atomic force microscopy and nano-indentation/scratch *** with that on the original enamel surface,the adsorption and lubrication behavior of salivary proteins remains almost unchanged on the heated enamel surface(where the enamel matrix proteins are denatured but the size of HA crystalline nanoparticles keeps constant)but exhibits an obvious compromise on the deproteinated enamel surface(where the enamel matrix proteins are removed and agglomeration of HA crystallites occurs).The HA agglomeration weakens the electrostatic interaction of enamel surfaces with salivary proteins to cause a distinct negative influence on the adsorption and pellicle-forming of salivary ***,the negative effect is confirmed with a quartz crystal microbalance with *** summary,by regulating enamel nanostructure for appropriate electrostatic interactions between salivary proteins and enamel surfaces,the enamel matrix proteins play an essential role in the adsorption and pellicle-forming of salivary proteins on human enamel,and then contribute to saliva lubrication,which provides the enamel with an anti-wear *** findings will promote and assist the design of enamel-inspired anti-wear materials.

关键词： enamel matrix proteins hydroxyapatite(HA)crystalline nanoparticles salivary proteins adsorption lubrication

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Evaluation of high-temperature tensile behavior for metal foils by a novel resistance heating assisted tensile testing system using samples with optimized structures

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Journal of Materials Science & Technology 2021年第35期94卷 216-229页

作者： qiu zheng Tsuyoshi Furushima Department of Mechanical and Biofunctional Systems Institute of Industrial ScienceThe University of Tokyo4-6-1 KomabaMeguro 153-8505TokyoJapan

To evaluate the tensile behavior of metal foils by resistance heating(RH)assisted tensile testing system accurately,this study proposed to embed a digital image correlation(DIC)system with laser speckles for the measurement of full-field strain ***,the sample structures were optimized to achieve uniform temperature and strain *** infrared camera was used to monitor the temperature *** samples instead of dog-bone shaped samples were proposed.A model for calculating the temperature distribution was established to optimize the sample *** parameters that influence the temperature distribution and tensile behavior were *** results,compared to the strain measured by a non-contact extensometer,the maximum deviation of the strain measured by DIC was less than 6%when the nominal strain was larger than *** is confirmed that the proposed tensile testing system is reliable for measuring the temperature and full-field strain *** shape influenced temperature distributions of smaller samples while it almost had no influence on the temperature distributions of larger *** temperature difference was not affected by the material type but by the sample *** proposed rectangular shape was validated to be feasible for RH assisted tensile *** sample length was successfully optimized for a more uniform temperature distribution by the established *** the tensile deformation was not influenced by the sample shape,the temperature distribution resulted in a non-uniform strain distribution before achieving ultimate tensile *** effective sample length between two clamping jigs contributed to a more uniform temperature distribution and material deformation.A more accurate evaluation of high-temperature tensile behavior for metal foils can be achieved by the proposed RH assisted tensile testing system using rectangular samples with an optimized structure.

关键词： High temperature Metal foil Resistance heating Sample structure Tensile behavior

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Measuring Policy Performance in Online Pricing with Offline Data:Worst-case Perspective and Bayesian Perspective

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Journal of Systems Science and Systems Engineering 2023年第3期32卷 352-371页

作者： yue Wang Zeyu zheng Department of Computational Medicine University of CaliforniaLos AngelesCA 90095USA Institut des Hautes Etudes Scientifiques Bures-sur-YvetteEssonne 91440France Department of Industrial Engineering and Operations Research University of CaliforniaBerkeleyCA 94720USA

The problems of online pricing with offline data,among other similar online decision making with offline data problems,aim at designing and evaluating online pricing policies in presence of a certain amount of existing offline *** evaluate pricing policies when offline data are available,the decision maker can either position herself at the time point when the offline data are already observed and viewed as deterministic,or at the time point when the offline data are not yet generated and viewed as *** write a framework to discuss how and why these two different positions are relevant to online policy evaluations,from a worst-case perspective and from a Bayesian *** then use a simple online pricing setting with offline data to illustrate the constructions of optimal policies for these two approaches and discuss their differences,especially whether we can decompose the searching for the optimal policy into independent subproblems and optimize separately,and whether there exists a deterministic optimal policy.

关键词： Online pricing offline data performance measure worst-case approach Bayesian approach

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A direct probabilistic approach to solve state equations for nonlinear systems under random excitation

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Acta Mechanica Sinica 2016年第5期32卷 941-958页

作者： zheng Lv Zhiping qiu Institute of Solid Mechanics Beihang University

In this paper, a direct probabilistic approach（DPA） is presented to formulate and solve moment equations for nonlinear systems excited by environmental loads that can be either a stationary or nonstationary random *** proposed method has the advantage of obtaining the response＇s moments directly from the initial conditions and statistical characteristics of the corresponding external excitations. First, the response＇s moment equations are directly derived based on a DPA, which is completely independent of the It？/filtering approach since no specific assumptions regarding the correlation structure of excitation are *** solving them under Gaussian closure, the response＇s moments can be obtained. Subsequently, a multiscale algorithm for the numerical solution of moment equations is exploited to improve computational efficiency and avoid much wall-clock time. Finally, a comparison of the results with Monte Carlo（MC） simulation gives good ***, the advantage of the multiscale algorithm in terms of efficiency is also demonstrated by an engineering example.

关键词： Direct probabilistic approach Nonlinear dynamic system Nonstationary random process Response’s moments Multiscale algorithm

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Using NH_(2)-MIL-125(Ti)for efficient removal of Cr(Ⅵ)and Rh B from aqueous solutions:Competitive and cooperative behavior in the binary system

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Journal of Environmental Sciences 2024年第2期136卷 437-450页

作者： Lei zheng Lixia Sun Jiangbo qiu Junling Song Luyi Zou yue Teng Yongzhong Zong Hongyan Yu School of Environmental and Civil Engineering Jiangnan UniversityWuxi 214122China School of Chemical and Material Engineering Jiangnan UniversityWuxi 214122China Kunming South Water Co. Ltd.Kunming 650501China Jiangsu Key Laboratory of Anaerobic Biotechnology Jiangnan UniversityWuxi 214122China

The coexistence of inorganic and organic contaminants is a challenge for real-life water treatment ***,in this research,we used NH_2-MIL-125(Ti)to evaluate the single adsorption of hexavalent chromium(Cr(Ⅵ))or Rhodamine B(RhB)in an aqueous solution and further investigate simultaneous adsorption experiments to compare the adsorption behavior *** main influencing factors,for example,reaction time,initial concentration,reaction temperature,and pH were studied in *** all reaction systems,the pseudo-second-order kinetic and Langmuir isotherm models were well illuminated the adsorption progress of Cr(Ⅵ)and *** studies showed that the adsorption process was spontaneous and *** compared to the single system,the adsorption capacity of Cr(Ⅵ)in the binary system gradually decreased as the additive amount of RhB increased,whereas the adsorption capacity of RhB in the binary system was expanded *** the binary reaction system contained 100 mg/L Cr(Ⅵ),the removal rate of RhB increased to 97.58%.The formation of Cr(Ⅵ)-RhB and Cr(Ⅲ)-RhB complexes was the cause that provided facilitation for the adsorption of *** findings prove that the interactions during the water treatment process between contaminants may obtain additional benefits,contributing to a better adsorption capacity of co-existing contaminant.

关键词： Adsorption Heavy metal ion Organic dye Simultaneous removal Mechanism studies

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兴伊措古生态记录揭示的近300年来气候变化及人类活动对青藏高原东南缘湖泊的影响

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湖泊科学 2025年第1期37卷 318-327页

作者：仇恒帅王荣赵雁捷朱可欣郑佳楠郑文秀刘阳胡捷梅雪英安徽农业大学资源与环境学院合肥230036 中国科学院南京地理与湖泊研究所南京211135 南京大学地球与海洋科学学院南京210023 湖北师范大学城市与环境学院黄石435002 巢湖市气象局合肥238000

青藏高原是生态系统响应全球变化研究的热点区域。目前,对该区域水生生物群落如何响应气候变化和人类活动的认识还存在不足,需要更多的研究案例。本研究以古湖沼学手段研究了青藏高原东南部的兴伊措过去300年来的湖泊生态系统演变历程... 详细信息

青藏高原是生态系统响应全球变化研究的热点区域。目前,对该区域水生生物群落如何响应气候变化和人类活动的认识还存在不足,需要更多的研究案例。本研究以古湖沼学手段研究了青藏高原东南部的兴伊措过去300年来的湖泊生态系统演变历程。研究结果显示,1930年之前沉积钻孔中生物指标硅藻以及理化指标变化不大,表明湖泊及其流域环境变化较为有限。1930年以来,该湖泊流域风化和侵蚀持续增加,湖泊营养水平上升。研究时间段内,硅藻群落中优势属种变化不明显,但稀有硅藻属种在1930年后出现显著变化。该研究认为,气候变化是兴伊措流域风化、侵蚀增加的主要原因,人类放牧活动可能加剧了气候变化的影响。当前的环境变化尚未对兴伊措水生生态系统优势类群造成显著影响,但湖泊中稀有属种自1930年以来的快速响应表明如果环境压力持续增加,未来该区域湖泊生态系统可能面临突变风险。

关键词：古湖沼学稀有属种侵蚀全球变化硅藻兴伊措

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Nitrogen-rich hierarchically porous carbon foams as high-performance electrodes for lithium-based dual-ion capacitor

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Journal of Energy Chemistry 2020年第9期29卷 187-194,I0006页

作者： yue Chen Xiaoming qiu Li-Zhen Fan Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Shanxi Key Laboratory of New Energy Materials and Devices Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

Nitrogen-rich porous carbonaceous materials have shown great potential in energy storage and conversion applications due to their facile fabrication,high electronic conductivity,and improved hydrophilic ***,three-dimensional porous N-rich carbon foams are fabricated through a one-step carbonization-activation method of the commercial melamine foam,and displaying hierarchically porous structure(macro-,meso-,and micro-pores),large surface area(1686.5 m2 g^-1),high N-containing level(3.3 at%),and excellent *** as-prepared carbon foams as electrodes for quasi-solid-state supercapacitors exhibit enhanced energy storage ability with 210 F g^-1 and 2.48c at 0.1 A g^-1,and150 F g^-1 and 1.77 F cm^-2 at 1 A g^-1,***,as an electrode for lithium-based dual-ion capacitor,this distinctive porous carbon also delivers remarkable specific capacitance with 143.6 F g^-1 at0.1 A g^-1 and 116.2 F g^-1 at 1 A g^-*** simple preparation method and the fascinating electrochemical performance endow the N-rich porous carbon foams great prospects as high-performance electrodes for electrochemical energy storage.

关键词： Nitrogen-rich Carbon foam Hierarchically porous structure Dual-ion capacitor

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Corrosion behavior of three Ag–50Cu alloys prepared by different processes in NaCl solutions

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Rare Metals 2017年第1期36卷 61-68页

作者： Zhong-qiu Jia qiu-Ying Liang qiu-yue Tian Zhong-qiu Cao Yan Wang College of Chemistry-and Chemical Engineering Shenyang Normal University Shenyang 110034 China

Corrosion behavior of two nanocrystalline bulk Ag–50Cu alloys and one coarse-grained counterpart prepared by liquid-phase reduction(LPR), mechanical alloying(MA) and powder metallurgy(PM) methods,respectively, were investigated in Na Cl solutions. They were finished by means of PARM273 A and M5210 electrochemical apparatus through potentiodynamic polarization method and electrochemical impedance spectroscopy(EIS) technique. The results show that corrosion rates of three Ag–50Cu alloys increase with the increment of Na Cl solution concentrations. Corrosion rates of LPRAg–50Cu alloy are a little higher than those of PMAg–50Cu alloy,but evidently lower than those of MAAg–50Cu alloy. The difference in corrosion rates is attributed to the large reduction in the grain size and homogeneous microstructure of nanocrystalline alloys. Passive current densities decrease and afterward increase for PMAg–50Cu alloy,decrease for MAAg–50Cu alloy, and increase for LPRAg–50Cu alloy with the increment of Na Cl solution concentrations. After the grain sizes are refined, passive current densities become lower.

关键词： Copper alloys Corrosion Corrosion rate Corrosive effects Electrochemical corrosion Electrochemical impedance spectroscopy Electrochemistry Grain size and shape Mechanical alloying Nanocrystals Powder metallurgy Reduction Silver Silver alloys

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Universal method for designing periodic orbits by homotopy classes in the elliptic restricted three-body problem

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Astrodynamics 2024年第1期8卷 175-188页

作者： yue zheng Min Zhao School of Electronic Engineering Xi’an Aeronautical InstituteXi’an710077China School of Aircraft Engineering Xi’an Aeronautical InstituteXi’an710077China School of Astronautics Northwestern Polytechnical UniversityXi’an710072China

The current methods for designing periodic orbits in the elliptic restricted three-body problem(ERTBP)have the disadvantages of targeting limited orbits and ergodic searches and considering only symmetric orbits.A universal method for designing periodic orbits is proposed in this ***,the homotopy classes of orbits are structured based on their topological ***,a dynamic model based on homotopy classes,ranging from the circular restricted three-body problem(CRTBP)to the ERTBP,can be built using the homotopy ***,a multi-and a single-period orbit were selected based on the resonance ***,the corresponding orbit in the ERTBP was computed by modifying the initial condition of the orbit in the *** method,without an ergodic search,can extend to any orbit,including an asymmetric orbit in the CRTBP,to the ERTBP model,and the two orbits are of the same homotopy *** of the Earth–Moon ERTBP are presented to verify the efficiency of this method.

关键词： periodic orbit elliptic restricted three-body problem(ERTBP) topology homotopy circular restricted three-body problem(CRTBP)

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Hard x-ray transmission curved crystal spectrometers(10–100 keV) for laser fusion experiments at the ShenGuang-Ⅲ laser facility

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High Power Laser Science and Engineering 2016年第1期4卷 9-16页

作者： Ming-hai Yu Guang-yue Hu Ning An Feng Qian Yu-chi Wu Xiao-ding Zhang Yu-qiu Gu qiu-ping Wang Jian zheng Department of Modern Physics & CAS Key Laboratory of Geospace Environment University of Science and Technology of China Research Center of Laser Fusion China Academy of Engineering Physics National Synchrotron Radiation Laboratory University of Science and Technology of China

Two transmission curved crystal spectrometers are designed to measure the hard x-ray emission in the laser fusion experiment of Compton radiography of implosion target on ShenGuang-III laser facility in China. Cylindrically curvedα-quartz(10–11) crystals with curvature radii of 150 and 300 mm are used to cover spectral ranges of 10–56 and17–100 ke V, respectively. The distance between the crystal and the x-ray source can be changed over a broad distance from 200 to 1500 mm. The optical design, including the integral reflectivity of the curved crystal, the sensitivity, and the spectral resolution of the spectrometers, is discussed. We also provide mechanic design details and experimental results using a Mo anode x-ray source. High-quality spectra were obtained. We confirmed that the spectral resolution can be improved by increasing the working distance, which is the distance between the recording medium and the Rowland circle.

关键词： curved crystal spectrometer hard x-ray laser fusion

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