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Nano Research 2024年第5期17卷 3895-3901页

作者： Rui Sui Bingyan Wang Yongsheng Wang Jiajing Pei Wei Zhu Wenxing Chen Chunhui Li Ailing Sun Zhongbin Zhuang Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China co.lege of Chemistry and Green Catalysis Center Zhengzhou UniversityZhengzhou 450001China State Key Lab of Organic-Inorganic co.posites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Energy&Catalysis Center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China

The electrochemical co.(2) reduction reaction(co.(2)RR)has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global ***,we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon(M-N-C)type catalyst by simply calcinating metal acetate and urea with co.mercial carbon black,which have potential application in co.(2)*** synthesized Ni-NC-600 catalyst has the structure of single Ni atom co.rdinated with one N atom and three C atoms(Ni-N_(1)C_(3)),which is suggested by X-ray absorption *** Ni-NC-600 catalyst exhibits high co.(2)RR catalytic performance and a high co.Faraday efficiency above 98%in a wide potential range from-0.7 to-1.3 V(*** hydrogen electrode(RHE)),superior to most of the reported Ni-N-C *** work has developed a facile strategy to synthesize high performance co.(2)RR catalyst.

关键词： nickel single atom catalyst co.(2)reduction reaction co.production electrocatalyst

Healing Behavior of Micropores in Powder Metallurgy 316L Stainless Steel during Hot Forging and Heat Treatment

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Journal of Iron and Steel Research International 2014年第9期21卷 862-868页

作者： Ying KAN Shi-hong ZHANG Li-wen ZHANG Ming CHENG Hong-wu SONG Hong-wei lu School of Materials Science and Engineering Dalian University of Technology Institute of Metal Research Chinese Academy of Sciences Forge Plant Angang Heavy Machine Co.Ltd.

The healing behavior of micropores in powder metallurgy （P/M） 316L stainless steel during hot forging and subsequent heat treatment was studied. The results showed that hot forging can improve the homogeneity of the pore size and enhance the relative density of material in varying degree due to different forging temperatures. As a re- sult of deformation and diffusion bonding at high temperature, the irregular pores were spheroidized and finally turned into stable inner grain pores. The co.parison of co.pression behavior between P/M and wrought dense mate rials has shown that the pores can either be the obstacles of dislocation movement or be the nucleation sites accelera- ting the reerystallization acco.ding to the difference of deformation temperatures.

关键词： powder metallurgy 316L stainless steel microstructural evolution densification behavior micropore

A Model of Spray Tool and a Parameter Optimization Method for Spraying Path Planning

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International Journal of Automation and co.puting 2021年第6期18卷 1017-1031页

作者： Ru-Xiang Hua Wei Zou Guo-Dong Chen Hong-Xuan Ma Wei Zhang School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100080China Institute of Automation Chinese Academy of SciencesBeijing 100190China Shandong Jonkin Intelligent technology co. LtdWeihai 264200China Inner Mongolia First Machinery Group of co. LtdBaotou 014000China

The digital camouflage spraying of special vehicles carried out by robots can greatly improve the spraying efficiency, spraying quality, and rapid adaptability to personalized patterns. The selection of spray tool and the accuracy of the adopted mathematical spray tool model has a great impact on the effectiveness of spray path planning and spraying quality. Since traditional co.ical spray tool models are not suitable for spraying rectangular digital camouflage, acco.ding to the characteristics of digital camouflage, the co.ting thickness cumulative distribution model of strip nozzle spray tool for 2 D plane spraying and 3 D surface spraying is derived, and its validity is verified by simulation. Based on the accumulation velocity model of the co.ting thickness(AVCT) on the curved surface and aiming at spraying path planning within the same surface and different surfaces, a path parameter optimization method based on co.ting uniformity evaluation of adjacent path overlapping area is proposed. co.bined with the vehicle surface model, parameters such as path interval, spray tool angle and spray tool motion velocity can be calculated in real-time to ensure uniform co.ting. Based on the known local three-dimensional model of vehicle surface and the co.prehensive spraying simulation, the validity of the purposed models: the co.ting thickness on the adjacent path area(CTAPA), the co.ting thickness on the intersection of two surfaces(CTITS), the co.ting thickness on the intersection of a plane and a surface(CTIPS), and the optimization method of path parameters are verified. The results show that co.pared with the traditional spray tool, the strip nozzle can better ensure the uniformity of the co.ting thickness of digital camouflage spray. Finally, acco.ding to a practical spraying experiment, the results prove that the proposed models not only are effective but also meet the practical industrial requirements and are of great practical value.

关键词： Digital camouflage spraying robot path optimization parameter setting co.ting thickness uniformity

co.bined effect of steel fibres and steel rebars on impact resistance of high performance co.crete

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Journal of Central South University 2011年第5期18卷 1677-1684页

作者：陈相宇丁一宁 C.Azevedo Shanghai Bekaert Ergang co. Ltd State Key Laboratory of co.stal and Offshore Engineering Dalian University of Technology Centre of Mathematics University of MinhoBraga 4700Portugal

The impact properties of normal co.crete (NC) and reinforced co.crete (RC) specimens,steel fibre reinforced co.crete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the drop-weight impact test reco.mended by ACI co.mittee *** results indicate that the number of blows to final failure is greatly increased by addition of steel ***,the co.bination of steel fibres and steel rebars demonstrates a significant positive co.posite effect on the impact resistance,which results in the improvement in impact toughness of co.crete *** the view of variation of impact test results,the two-parameter Weibull distribution was adopted to analyze the experimental *** is proved that the probabilistic distributions of the blows to first crack and to final failure of six types of samples approximately follow two-parameter Weibull distribution.

关键词： impact resistance high performance co.crete fibre Weibull distribution

Enhanced treatment of water with low turbidity:co.bined effects of permanganate, PAM and recycled sludge

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Journal of Harbin Institute of technology(New Series) 2009年第6期16卷 863-868页

作者：孙丽华吕谋杨艳玲林建禄周玲玲李圭白 School of Municipal and Environmental Engineering Harbin Institute of Technology School of Environmental and Municipal Engineering Qingdao Technological University School of Architecture and Civil Engineering Beijing University of Technology Suzhou Litree Purifying technology co. LTD.

The effectiveness of enhancing treatment of water with low turbidity through co.bined effects of permanganate oxidation, PAM aiding co.gulation and sludge recycling was investigated through co.tinuous bench scale studies. In co.paring with ferric chloride co.gulation, only recycling sedimentation sludge was ineffective in enhancing treatment of water with low turbidity. PAM with recycled sludge showed positive effects, and the additional permanganate dosing exhibited the best potential of favoring co.gulation, which leaded to much lower effluent turbidity and co.Ma. Additionally, it was observed that the optimal permanganate dosage was 0. 4 mg/ L and the higher permanganate dosage exhibited inhibiting effects for pollutants removal. SEM analysis indicated that the floes were loosely formed and the particle diameter was critically low for ferric chloride co.gulation process. co.paratively, the addition of PAM and permanganate with recycled sludge facilitated the aggregation of tinny particles onto co.pact PAM polymer chains, therefore co.tributing to the formation of co.pact floes with high particle diameter. The co.bined employment of recycled sludge, PAM and permanganate showed the best potential of favoring co.gulation, mainly through synergistic effects between seeding, polymer bridging and increasing effective co.lision in mechanism. Additionally, the variation of Fe and Mn co.centration after recycling and sedimentating units was studied for the processes, and the main species was also investigated for elements Fe and Mn. Sludge recycling and permanganate addition did not increase Fe and Mn co.centration in the sedimented water.

关键词： water with low turbidity permanganate recycled sludge seeding polymer bridging

Intertidal area classification with generalized extreme value distribution and Markov random field in quad-polarimetric synthetic aperture radar imagery

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Frontiers of Information technology & Electronic Engineering 2019年第2期20卷 253-264页

作者： Ting-ting JIN Xiao-qiang SHE Xiao-lan QIU Bin LEI Key Laboratory of technology in Geo-spatial Information Processing and Application System Institute of ElectronicsChinese Academy of Sciences University of Chinese Academy of Sciences Huawei Software Technologies co. Ltd.

Classification of intertidal area in synthetic aperture radar(SAR) images is an important yet challenging issue when co.sidering the co.plicatedly and dramatically changing features of tidal fluctuation. The difficulty of intertidal area classification is co.pounded because a high proportion of this area is frequently flooded by water, making statistical modeling methods with spatial co.textual information often ineffective. Because polarimetric entropy and anisotropy play significant roles in characterizing intertidal areas, in this paper we propose a novel unsupervised co.textual classification algorithm. The key point of the method is to co.bine the generalized extreme value(GEV) statistical model of the polarization features and the Markov random field(MRF) for co.textual smoothing. A goodness-of-fit test is added to determine the significance of the co.ponents of the statistical model. The final classification results are obtained by effectively co.bining the results of polarimetric entropy and anisotropy. Experimental results of the polarimetric data obtained by the Chinese Gaofen-3 SAR satellite demonstrate the feasibility and superiority of the proposed classification algorithm.

关键词： Intertidal classification Polarimetric synthetic aperture radar Finite mixture model Markov random field Generalized extreme value model

Rice melatonin deficiency causes premature leaf senescence via DNA methylation regulation

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The Crop Journal 2024年第3期12卷 721-731页

作者： Yue lu Ahmed Gharib Rujia Chen Hanyao Wang Tianyun Tao Zhihao Zuo Qing Bu Yanze Su Yaoqing Li Yanmo luo Hamdi F.El-Mowafi Zhichao Wang Qianfeng Huang Shuting Wang Yang Xu Pengcheng Li Chenwu Xu Zefeng Yang Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Zhongshan Biological Breeding Laboratory/Key Laboratory of Plant Functional Genomics of the Ministry of Education Agriculture College of Yangzhou UniversityYangzhou 225009JiangsuChina Jiangsu co.Innovation Center for Modern Production technology of Grain Crops Jiangsu Key Laboratory of Crop Genetics and PhysiologyYangzhou UniversityYangzhou 225009JiangsuChina National Institute of Laser Enhanced Sciences(NILES) Cairo UniversityGiza 12613Egypt Rice Research Department Field Crops Research InstituteAgricultural Research CenterSakhaKafr El-Sheikh 33717Egypt

In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain *** deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf *** of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-co.ing genes and transposable element-related *** in gene expression and DNA methylation in the melatonin-deficient mutants were co.pensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have co.tributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark co.ditions.

关键词： Melatonin Premature leaf senescence Rice DNA methylation Epigenetic regulation

On the characterization of microstructure and fracture in a high-pressure die-casting Al-10 wt%Si alloy

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Progress in Natural Science:Materials International 2020年第2期30卷 221-228页

作者： Xiangyi Jiao Chaofeng Liu Jun Wang Zhipeng Guo Junyou Wang Zhuoming Wang Junming Gao Shoumei Xiong School of Materials Science and Engineering Tsinghua University Key Laboratory for Advanced Materials Processing technology Tsinghua University Hong Bang Die Casting (NanTong) co. LTD

Microstructure and fracture behavior in a high-pressure die-casting Al-10 wt%Si alloy have been investigated using optical microsco.e(OM),scanning electron microsco.e(SEM) and a high-resolution laboratory co.puted tomography(CT).The results showed that a typical heterogeneous microstructure of the alloy co.prised α-Al rich region,eutectic silico. band region and *** microstructure patterns highly dependent on fluid co.vection and rapid *** high filling speed,externally solidified crystals(ESCs) and the growing dendrites migrated in center and formed α-Al rich *** particles was discharged and enriched in the final solidified liquid,forming eutectic silico. *** Si particles and brittle Fe-rich phases served as obstacles prevented dislocation migration,causing local stress *** to large movable slip systems in α-Al rich region,the propagation path of the crack was greatly ***-shrinkage that induced by dense impinging dendrites led to the microcracks along the boundary of dendrites which promoted intergranular fracture.

关键词： Fracture Hypoeutectic Al-10Si Microstructure heterogeneity High-pressure die-casting

Analytical solutions of ground settlement induced by yaw in a space curved shield tunnel

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Underground Space 2023年第6期13卷 86-103页

作者： Jiannan Xie Pengfei Li Mingju Zhang Fei Jia Shaohua Li Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China China Railway No.3 Engineering Group No.4 Engineering co. Ltd.Beijing 102300China China Railway 15th Bureau Group co. Ltd.Shanghai 200070China

This paper aims to provide the analytical solutions of the ground settlement for a space curved shield tunnel in the case of yaw *** inducements include ground loss and co.struction loads,and two co.responding analytical models have been proposed in this ***-dimensional image theory has been adopted to calculate the ground settlement due to ground *** parameters are introduced into the calculation model to deduce the relevant laws of the ground *** on modified Mindlin solutions,analytical models are established to calculate the ground settlement induced by co.struction loads,such as the frontal additional thrust,axial friction of shield shell,and the grouting *** method of calculating the position of the shield machine in the ground is refined,and the influence area of co.struction loads from the shield machine is ***,the obtained solutions are validated by a numerical model and field ***,a co.parison reveals that the proposed model is the co.position of three classical analytical models,thus it excels them in solving the problem ***,parametric analyses of yaw are co.ducted to examine yaw angle and pitch angle on ground *** proposed model can effectively predict ground settlement caused by the spatial linear shield tunneling process.

关键词： Shield tunnel Space line Yaw excavation Ground loss co.struction load Ground settlement

Degradation of chemical and mechanical properties of cements with different formulations in co.(2)-co.taining HTHP downhole environment

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Petroleum Science 2023年第2期20卷 1119-1128页

作者： Wei Yan Hao-Guang Wei Nguu Dickson Muchiri Fu-Li Li Jing-Ru Zhang Zheng-Xian Xu State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China Sinopec Petroleum Engineering technology Research Institute co. Ltd.Beijing102206China

The increasing energy demand has pushed oil and gas exploration and development limits to extremely challenging and harsher HTHP (High Temperature and High Pressure) environments. Maintaining wellbore integrity in these environments, particularly in HPHT reservoirs with co.rosive gases, presents a significant challenge. Robust risk evaluation and mitigation strategies are required to address these reservoirs' safety, eco.omic, and environmental uncertainties. This study investigates chemo-mechanical properties degradations of class G oil well cement blended with silica fume, liquid silica, and latex when exposed to high temperature (150 °C) and high partial pressure of co.(2) saturated brine. The result shows that these admixtures surround the cement grains and fill the interstitial spaces between the cement particles to form a dense crystal system of C–S–H. co.sequently, the cement's percentage of pore voids, permeability, and the co.tent of alkali co.pounds reduce, resulting in increased resistance to co.(2) co.rosion. Liquid silica, a specially prepared silica suspension, is a more effective alternative to silica fume in protecting oil well cement against co.(2) chemical degradation. Micro-indentation analysis shows a significant deterioration in the mechanical properties of the cement, including average elastic modulus and hardness, particularly in the outer zones in direct co.tact with co.rosive fluids. This study highlights the significance of inco.porating admixtures to mitigate the effects of co.(2) co.rosion in HPHT environments and provides a valuable technique for quantitatively evaluating the mechanical-chemical degradation of cement sheath.

关键词： HPHT reservoirs Oil well cement co.(2)co.rosion Chemo-mechanical Mechanical properties Micro-indentation