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Oxidation behaviour of electron beam physical vapour deposition β-NiAlHf coatings at 1100℃ in dry and humid atmospheres

2013年中国药学大会暨第十三届中国药师周

作者： kai-kai gong Ping-Lin Li Xing-Wang Zhang Nai-Xia Zhang Lei Xue Wen-Juan Song Xu-Li Tang Guo-Qiang Li Key Laboratory of Marine Drugs Chinese Ministry of Education School of Medicine and Pharmacy Ocean University of China College of Chemistry and Chemical Engineering Ocean University of China

Chemical investigation of the aerial parts of mangrove plant Sonneratia Paracaseolaris yielded five new triterpenoids paracaseolins A E （1 4, and 11） together with twelve known ones （5 10, 12 17）. Their structures were established by extensive spectroscopic methods and comparison of their spectroscopic data with those of the related known compounds. The cytotoxicities against P388, HeLa, A549 and K562 tumor cell lines and anti-H1N1 （Influenza A virus） activities for the isolates were evaluated. Compound 4 showed potent cytotoxicity against A549 cell line with IC 50 value of 1.89 M. A preliminary SAR was discussed, and the 3 -coumaroyl group was suggested as an essential pharmacophore for their cytotoxicities against P388, HeLa and A549 cell lines. Besides, compound 1 exhibited significant anti-H1N1 virus activity with IC 50 value of 28.4 g/mL.

关键词： Mangrove plant Sonneratia Paracaseolaris Sonneratiaceae triterpenoids cytotoxicities anti-H1N1 activities

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Rare Metals 2016年第7期35卷 513-519页

作者： kai Yan Hong-Bo Guo Hui Peng Sheng-kai gong School of Materials Science and Engineering Beihang University Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang University

NiA1 intermetallic compounds attract increas- ing attention for high-temperature applications due to their combination of excellent properties, especially as metallic protective coatings on superalloys or as bond coats in thermal barrier coatings （TBCs）. Oxidation behaviour of the β-NiA1Hf coatings prepared by electron beam physical vapour deposition （EB-PVD） was investigated at 1100 ℃ for short time and 100h in 20% 02＋Ar and 15 % H20 ＋ Ar, respectively. The results of mass changes re- veal that the addition of minor reactive element Hf sig- nificantly improves the cyclic oxidation resistance of the 13- NiA1 coatings in both dry and humid atmospheres. During the initial oxidation stage, water vapour retards the phase transformation from 0-A1203 to a-A1203. Moreover, com- pared with the case in dry atmosphere, water vapour sig- nificantly reduces the surface roughness of the oxide scales formed on EB-PVD β-NiA1Hf coatings after 100 h cyclic oxidation, which corresponds with the difference of surface morphologies of the oxide scales.

关键词： β-NiA1Hf coatings Water vapour Oxidation Phase transformation Roughness

Effect of boundary conditions on shakedown analysis of heterogeneous materials

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen gong Yinghao NIE Gengdong CHENG kai LI State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under ***, utilizing PBCs to

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

Effect of Sintering on Thermal Conductivity and Thermal Barrier Effects of Thermal Barrier Coatings

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Chinese Journal of Aeronautics 2012年第5期25卷 811-816页

作者： WANG kai PENG Hui GUO Hongbo gong Shengkai School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Thermal barrier coatings （TBCs） are mostly applied to hot components of advanced turbine engines to insulate the compo- nents from hot gas. The effect of sintering on thermal conductivity and thermal barrier effects of conventional plasma sprayed and nanostructured yttria stabilized zirconia （YSZ） thermal barrier coatings （TBCs） are investigated. Remarkable increase in thermal conductivity occurs to both typical coatings after heat treatment, The change of porosity is just the opposite. The grain size of the nanostructured zirconia coating increases more drastically with annealing time compared to that of the conventional plasma sprayed coating, which indicates that coating sintering makes more contributions to the thermal conductivity of the nanostructured coating than that of the conventional coating. Thermal barrier effect tests using temperature difference technique are performed on both coatings. The thermal barrier effects decrease with the increase of thermal conductivity after heat treat- ment and the decline seems more drastic in low thermal conductivity range. The decline in thermal barrier effects is about 80℃ for nanostructured coating after 100 h heat treatment, while the conventional coating reduces by less than 60 ℃ compared to the as-sprayed coating.

关键词： thermal barrier coatings (TBCs) sintering thermal conductivity thermal insulation laser flash method

Sub-micron Co-Al_(2)O_(3) composite powders prepared by room-temperature ultrasonic-assisted electroless plating

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Rare Metals 2022年第6期41卷 1968-1971页

作者： Liu Zhu Hong-Bo Guo Sheng-kai gong School of Materials Science and Engincering Beihang UniversityBeijing 100191China Department of Mechanical Engineering Taizhou UniversityTaizhou 318000China

Sub-micron Co-Al_(2)O_(3)composite powders were synthesized by ultrasonic-assisted electroless plating process at room temperature with a one-step activating method *** effect of process parameters on plating rate,Co content,and the uniformity of cobalt layer was analyzed by transmission electron microscopy(TEM).The results show that as the initial pH values of plating bath increase,the plating rate *** plating rate declines as the load increases when the load of powders is less than 12 g·L^(-1),but increases when the load is greater than 12 g·L^(-1).The relative Co content of the Co-Al_(2)O_(3) powder declines with the powder load increasing.

关键词： Ultrasonic-assisted electroless plating Co-Al_(2)O_(3)compositepowders Load

Investigations on Fluid Resonance Within A Narrow Gap Formed by Two Fixed Bodies with Varying Breadth Ratios

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China Ocean Engineering 2023年第6期37卷 962-974页

作者： gong Shu-kai GAO Jun-liang MAO Hong-fei School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China College of Ocean Engineering and Energy Guangdong Ocean UniversityZhanjiang 524000China Guangdong Provincial Key Laboratory of Intelligent Equipment for South China Sea Marine Ranching Guangdong Ocean UniversityZhanjiang 524088China

The resonant motion of the fluid inside a narrow gap between two fixed boxes induced by incident regular waves with various wave heights is investigated by adopting a two-dimensional numerical wave flume based on an opensourced CFD package,*** two boxes have identical draft and height,but the upstream box has a variable *** article focuses on the influences of the breadth ratio,defined as the ratio of the breadth of the upstream box to that of the downstream box,on the following three aspects of hydrodynamic characteristics of gap resonance:(1)the wave height amplifications inside the gap,and in front and at the rear of the structure system,(2)the reflection,transmission,and energy loss coefficients of the structure system,and(3)the response and damping time of the fluid *** is found that the fluid resonant frequency,the amplification factor of the resonant wave height inside the gap and the maximum energy loss coefficient of the structure system are shown to gradually decrease with the increase of the breadth *** response time of gap resonance is shown to first increase and then decrease with the breadth ratio overall,regardless of the incident wave height,and the configuration that the two boxes have the same breadth would bring the largest response time of gap resonance.

关键词： gap resonance wave amplification varying breadth ratios OpenFOAM

Influence of Mechanical Behavior between the Grains on Stress Fluctuation of Aluminum Alloy Thick Plate

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Journal of Wuhan University of Technology(Materials Science) 2013年第6期28卷 1212-1216页

作者： LIAO kai WU Yunxin gong Hai School of Mechanical and Electrical Engineering Central South University of Forestry and Technology Guilin University of Electrical Technology School of Mechanical and Electrical Engineering Central South University

The research on fluctuation and inhomogeneity of internal stress of aluminum alloy thick plate is theoretical and technological base for stress control technology. By using X-ray diffraction technique and mechanical test method, aluminum alloy with typical fine sub-grains, coarse recrystallized grains, and second phase was analyzed; the interactive mechanical model between grains was built for analysis of variation of internal stress within the local micro structure by imitating the actual distribution of grains. The experimental result shows that the mechanical model can effectively explain the reason for fluctuation of microscopic stress, which also proves that the inhomogeneous distribution of metal organization is the cause for the complex distribution of microscopic stress. The model can well describe stress distribution of thick plate caused by thermal deformation. Besides, it well describes mechanism of stress fluctuation.

关键词： aluminum alloy stress fluctuation internal stress plastic deformation

Visible light triggered exfoliation of COF micro/nanomotors for efficient photocatalysis

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Green Energy & Environment 2023年第2期8卷 567-578页

作者： kai Feng Liang Zhang Jiang gong Jinping Qu Ran Niu Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China The State Key Laboratory Breeding Base of Basic Science of Stomatology(Hubei-MOST)&Key Laboratory of Oral Biomedicine Ministry of Education School and Hospital of StomatologyWuhan UniversityWuhan 430079China National Engineering Research Center of Novel Equipment for Polymer Processing Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSchool of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou510641China

We report a new facile light-induced strategy to disperse micron-sized aggregated bulk covalent organic frameworks(COFs)into isolated COFs *** was achieved by a series of metal-coordinated COFs,namely COF-909-Cu,-Co or-Fe,where for the first time the diffusio-phoretic propulsion was utilized to design COF-based micro/*** mechanism studies revealed that the metal ions decorated in the COF-909 backbone could promote the separation of electron and holes and trigger the production of sufficient ionic and reactive oxygen species under visible light *** this way,strong light-induced self-diffusiophoretic effect is achieved,resulting in good dispersion of *** them,COF-909-Fe showed the highest dispersion performance,along with a drastic decrease in particle size from 5μm to500 nm,within only 30 min light irradiation,which is inaccessible by using traditional magnetic stirring or ultrasonication *** importantly,benefiting from the outstanding dispersion efficiency,COF-909-Fe micro/nanomotors were demonstrated to be efficient in photocatalytic degradation of tetracycline,about 8 times faster than using traditional magnetic stirring *** work opens up a new avenue to prepare isolated nanosized COFs in a high-fast,simple,and green manner.

关键词： Micro/nanomotor COFs Exfoliation Nanocatalyst Photocatalysis

Arrayed Cobalt Phosphide Electrocatalyst Achieves Low Energy Consumption and Persistent H2 Liberation from Anodic Chemical Conversion

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Nano-Micro Letters 2020年第11期12卷 154-167页

作者： kai Zhang gong Zhang Qinghua Ji Jiuhui Qu Huijuan Liu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco‑Environmental SciencesChinese Academy of SciencesBeijing 100085People’s Republic of China Center for Water and Ecology State Key Joint Laboratory of Environment Simulation and Pollution ControlSchool of EnvironmentTsinghua UniversityBeijing 100084People’s Republic of China Key Laboratory of Drinking Water Science and Technology Research Center for Eco‑Environmental SciencesChinese Academy of SciencesBeijing 100085People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Electrochemical reduction of water to hydrogen(H2) offers a promising strategy for production of clean energy,but the design and optimization of electrochemical apparatus present challenges in terms of H2 recovery and energy *** cobalt phosphide nanoarrays(Co2 P/CoP NAs) as a charge mediator,we effectively separated the H2 and O2 evolution of alkaline water electrolysis in time,thereby achieving a membrane-free pathway for H2 *** hierarchical array structure and synergistic optimization of the electronic configuration of metallic Co2 P and metalloid CoP make the Co2 P/CoP NAs high-efficiency bifunctional electrocatalysts for both charge storage and hydrogen *** investigations revealed that the introduction of Co2 P into CoP leads to a moderate hydrogen adsorption free energy and low water dissociation barrier,which are beneficial for boosting HER ***,Co2 P/CoP NAs with high capacitance could maintain a cathodic H2 evolution time of 1500 s at 10 mA cm^(-2) driven by a low average voltage of 1.38 ***,the energy stored in the mediator could be exhausted via coupling with the anodic oxidation of ammonia,whereby only 0.21 V was required to hold the current for 1188 *** membrane-free architecture demonstrates the potential for developing hydrogen purification technology at low cost.

关键词： Electrocatalysis Cobalt phosphide Hydrogen purification Ammonia oxidation reaction Membrane-free architecture