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Microstructure evolution and nucleation mechanism of Inconel 601H alloy welds by vibration-assisted GTAW

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International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 788-799页

作者： Ze-long wang zhen-tai zheng Li-bing Zhao yun-feng Lei Kun Yang School of Materials Science and Engineering Hebei University of TechnologyTianjin 300130China Beiyang Chemical Equipment of Tianjin University Co. Ltd.Tianjin 300110China

Nickel-based alloys exhibit excellent high-temperature stxengtfi and oxidation resistance; however, because of coarse grains and severe segregation in daeir welding joints, these alloys exhibit increased susceptibility to hot cracking. In this paper, to improve the hot-cracking resistance and mechaxtical properties ofinckel-based alloy welded joints, sodium daiosulfate was used to simulate crystallization, enabling the nucleation mechanism under mechaxtical vibration to be investigated. On the basis of the results, the grain refinement mechan- ism during the gas tungsten arc welding （GTAW） of Inconel 601H alloy under wxious vibration modes and parameters was investigated. Compared witfi the GTAW process, the low-frequency mechanical vibration processes resulted in substantial grain refinement effects in the welds; thus, a higher haxdness distxibution was also achieved under the vibration conditions. In addition, the 7＇ phase exhibited a dispersed distribution and segregation was improved in the welded joints witfi vibration assistance. The results demonstxated that the generation of free crystals caused by vibration in the nucleation stage was the main mechaxtism of grain refinement. Also, free equiaxed grains and a dispersed 7＇ phase were found to improve the grain-boundary strength and reduce the segregation, contributing to preventing the initiation of welding hot cracking in nickel-based alloys.

关键词： mechanical vibration nickel-based alloy grain refinement microst3-ucture hot cracking

Preparation and performance evaluation of the slickwater using novel polymeric drag reducing agent with high temperature and shear resistance ability

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Petroleum Science 2024年第2期21卷 1113-1121页

作者： Ming-Wei Zhao zhen-feng Ma Cai-Li Dai WeiWu Yong-Quan Sun Xu-Guang Song yun-long Cheng xiang-Yu wang National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Shandong Key Laboratory of Oilfield Chemistry China University of Petroleum(East China)Qingdao266580ShandongChina Sinopec Shengli Oilfield Dongying257001ShandongChina Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 1H9Canada East China Petroleum Bureau of Sinopec Nanjing210011JiangsuChina

Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction ***,their performance is severely affected at high *** reducing agent is the key to determine the drag reducing performance of *** this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant *** slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and *** contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ***,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing ***,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.

关键词： Unconventional resources Polymeric drag reducing agent Slickwater High drag reduction rate Temperature resistance

Responses of Plant Community and Soil Properties to Inter-Annual Precipitation Variability and Grazing Durations in a Desert Steppe in Inner Mongolia

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Journal of Integrative Agriculture 2014年第6期13卷 1171-1182页

作者： wang zhen yun xiang-jun WEI Zhi-jun Michael P Schellenberg wang yun-feng YANG Xia HOU xiang-yang Grassland Research Institute Chinese Academy of Agricultural Sciences Department of Grassland Science College of Ecology and Environmental ScienceInner Mongolia Agricultural University Semiarid Prairie Agricultural Research Center (SPARC) Agriculture and Agri-Food Canada

Grazing can dramatically affect arid grassland communities that are very vulnerable to environmental changes due to its relatively short and sparse ground coverage, low biomass, sandy soil and inter-annual precipitation found in the desert steppe. The study investigates the effects of different grazing durations on vegetation and soil properties of a desert steppe community. The experiment was conducted in Xisu Banner in Inner Mongolia with ifve treatments：CG （continuous grazing）, 40UG （40 d ungrazed）, 50UG （50 d ungrazed）, 60UG （60 d ungrazed） and UG （ungrazed）. The biomass of both shrub and annual-biennial plant communities were signiifcantly decreased by CG. Continuous grazing and 40UG signiifcantly reduced the ANPP （aboveground net primary productivity） by the end of the three year study. 60UG treatment increased soil organic carbon （OC）, total nitrogen concentration （TN） and total phosphorus concentration （TP） concentrations and 50UG increased the TN and total phosphorus concentration （TK） concentrations, whereas CG, 40UG and 50UG decreased soil OC, TP and available phosphorus concentration （AP） concentrations. The perennial plant species of the desert steppe were generally tolerant for grazing. The annual-biennial plant species had large variability in ANPP because of the inter-annual precipitation. Our results highlight that inter-annual precipitation variations could strongly modify the community responses to grazing in arid ecosystems.

关键词： ANPP plant species plant fimctional group soil nutrient

Hollow carbon spheres and their noble metal-free hybrids in catalysis

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Frontiers of Chemical Science and Engineering 2021年第6期15卷 1380-1407页

作者： xiang-Hui Yu Jin-long Yi Ru-Liang Zhang feng-yun wang Lei Liu School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao266590China College of Physics and State Key Laboratory of Bio Fibers and Eco Textiles Qingdao UniversityQingdao 266071China

Hollow carbon spheres have garnered great interest owing to their high surface area,large surface-tovolume ratio and reduced transmission ***,we overview hollow carbon sphere-based materials and their noble metal-free hybrids in ***,we summarize the key fabrication techniques for various kinds of hollow carbon spheres,with a particular emphasis on controlling pore structure and surface morphology,and then heterogeneous doping as well as their metal-free/containing hybrids are presented;next,possible applications for non-noble metal/hollow carbon sphere hybrids in the area of energy-related catalysis,including oxygen reduction reaction,hydrogen evolution reaction,oxygen evolution reaction,water splitting,rechargeable Zn-air batteries and pollutant degradation are discussed;finally,we introduce the various challenges and opportunities offered by hollow carbon spheres from the perspective of synthesis and catalysis.

关键词： hollow carbon spheres functionalization noble metal-free catalysis

Effects of magnetic fields on Fe–Si composite electrodeposition

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International Journal of Minerals,Metallurgy and Materials 2014年第12期21卷 1175-1186页

作者： Qiong long yun-bo Zhong Huai wang Tian-xiang zheng Jun-feng Zhou Zhong-ming Ren Shanghai Key Laboratory of Modern Metallurgy and Material Processing Shanghai University

Coatings containing Fe-Si particles were electrodeposited on 3.0wt% Si steel sheets under magnetic fields. The effects of magnetic flux density （MFD）, electrode arrangement and current density on the surface morphology, the silicon content in the coatings and the cathode current efficiency were investigated. When a magnetic field was applied parallel to the current and when the MFD was less than 0.5 T, numerous needle-like structures appeared on the coating surface. With increasing MFD, the needle-like structures weakened and were transformed into dome-shaped structures. Meanwhile, compared to results obtained in the absence of a magnetic field, the silicon content in the coatings significantly increased as the MFD was increased for all of the samples obtained using a vertical electrode system. However, in the case of an aclinic electrode system, the silicon content decreased. Furthermore, the cathode current efficiency was considerably diminished when a magnetic field was applied. A possible mechanism for these phenomena was discussed.

关键词： composite coatings electrodeposition silicon steel magnetic field surface morphology silicon content magnetohydrodynamics

Towards Interpretable Defense Against Adversarial Attacks via Causal Inference

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Machine Intelligence Research 2022年第3期19卷 209-226页

作者： Min Ren yun-long wang Zhao-feng He University of Chinese Academy of Sciences Beijing 100190China Center for Research on Intelligent Perception and Computing National Laboratory of Pattern RecognitionInstitute of AutomationChinese Academy of SciencesBeijing 100190China Laboratory of Visual Computing and Intelligent System Beijing University of Posts and TelecommunicationsBeijing 100876China

Deep learning-based models are vulnerable to adversarial attacks. Defense against adversarial attacks is essential for sensitive and safety-critical scenarios. However, deep learning methods still lack effective and efficient defense mechanisms against adversarial attacks. Most of the existing methods are just stopgaps for specific adversarial samples. The main obstacle is that how adversarial samples fool the deep learning models is still unclear. The underlying working mechanism of adversarial samples has not been well explored, and it is the bottleneck of adversarial attack defense. In this paper, we build a causal model to interpret the generation and performance of adversarial samples. The self-attention/transformer is adopted as a powerful tool in this causal model. Compared to existing methods, causality enables us to analyze adversarial samples more naturally and intrinsically. Based on this causal model, the working mechanism of adversarial samples is revealed, and instructive analysis is provided. Then, we propose simple and effective adversarial sample detection and recognition methods according to the revealed working mechanism. The causal insights enable us to detect and recognize adversarial samples without any extra model or training. Extensive experiments are conducted to demonstrate the effectiveness of the proposed methods. Our methods outperform the state-of-the-art defense methods under various adversarial attacks.

关键词： Adversarial sample adversarial defense causal inference interpretable machine learning transformers

Coupling effect of micro-textured tools and cooling conditions on the turning performance of aluminum alloy 6061

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Advances in Manufacturing 2023年第4期11卷 663-681页

作者： Guo-Liang Liu Jin-Tao zheng Chuan-zhen Huang Shu-feng Sun Xin-Fu Liu long-Jie Dai De-xiang wang xiang-Yu wang Key Lab of Industrial Fluid Energy Conservation and Pollution Control Ministry of EducationKey Lab of Industrial Fluid Energy Conservation and Pollution ControlMinistry of EducationSchool of Mechanical and Automotive EngineeringQingdao University of TechnologyQingdao266520ShandongPeople’s Republic of China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha410083People’s Republic of China Key Laboratory of High-Efficiency and Clean Mechanical Manufacture(Ministry of Education) School of Mechanical EngineeringShandong UniversityJinan250061People’s Republic of China School of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiPeople’s Republic of China Qingdao Choho Ind Co Ltd Qingdao266705ShandongPeople’s Republic of China School of Mechanical Engineering University of JinanJinan250022People’s Republic of China

Micro-texturing has been widely proven to be an effective technology for achieving sustainable ***,the performance of micro-textured tools under different cooling conditions,especially their coupling effect on machined surface integrity,was scarcely *** this paper,the non-textured,linear micro-grooved,and curvilinear micro-grooved inserts were used to turn aluminum alloy 6061 under dry,emulsion,and liquid nitrogen cryogenic cooling *** coupling effects of different micro-textures and cooling conditions on cutting force,cutting temperature,and machined surface integrity,including the surface roughness,work hardening,and residual stress,were revealed and discussed in *** indicated that the micro-grooved tools,especially the curvilinear micro-grooved tools,not only reduced the cutting force and cutting temperature,but also improved the machined surface *** addition,the micro-grooved tools can cooperate with the emulsion or liquid nitrogen to reduce the cutting force,cutting temperature,and improve the machined surface integrity generally,although the combination of emulsion cooling condition and micro-grooved tools generated negative coupling effects on cutting forces and surface work ***,the combination of curvilinear micro-grooved cutting tools and cryogenic cooling condition resulted in the lowest cutting force and cutting temperature,which generated the surface with low roughness,weak work hardening,and compressive residual stress.

关键词： Micro-grooved cutting tool Cooling condition Cutting force Cutting temperature Surface integrity

Geophysical prediction of organic matter abundance in source rocks based on geochemical analysis:A case study of southwestern Bozhong Sag,Bohai Sea,China

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Petroleum Science 2024年第1期21卷 31-53页

作者： xiang wang Guang-Di Liu Xiao-Lin wang Jin-feng Ma zhen-Liang wang Fei-long wang Ze-Zhang Song Chang-Yu Fan State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China College of Geosciences China University of Petroleum(Beijing)Beijing102249China State Key Laboratory of Continental Dynamics Northwest UniversityXi'an710069ShaanxiChina Department of Geology Northwest UniversityXi'an710069ShaanxiChina CNOOC Tianjin Branch Company Tianjin300459China

The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin,and the source rocks of Paleogene Dongying and Shahejie Formations were buried *** of the drillings were located at the structural high,and there were few wells that met good quality source rocks,so it is difficult to evaluate the source rocks in the study area precisely by geochemical analysis *** on the Rock-Eval pyrolysis,total organic carbon(TOC)testing,the organic matter(OM)abundance of Paleogene source rocks in the southwestern Bozhong Sag were evaluated,including the lower of second member of Dongying Formation(E_(3)d2L),the third member of Dongying Formation(E_(3)d_(3)),the first and second members of Shahejie Formation(E_(2)s_(1+2)),the third member of Shahejie Formation(E_(2)s_(3)).The results indicate that the E_(2)s_(1+2)and E_(2)s_(3)have better hydrocarbon generative potentials with the highest OM abundance,the E_(3)d_(3)are of the second good quality,and the E_(3)d2L have poor to fair hydrocarbon generative ***,the well logs were applied to predict TOC and residual hydrocarbon generation potential(S_(2))based on the sedimentary facies classification,usingΔlogR,generalizedΔlogR,logging multiple linear regression and BP neural network *** various methods were compared,and the BP neural network method have relatively better prediction *** on the pre-stack simultaneous inversion(P-wave impedance,P-wave velocity and density inversion results)and the post-stack seismic attributes,the three-dimensional(3D)seismic prediction of TOC and S_(2)was carried *** results show that the seismic near well prediction results of TOC and S_(2)based on seismic multi-attributes analysis correspond well with the results of well logging methods,and the plane prediction results are identical with the sedimentary facies map in the study *** TOC and S_(2)values of E_(2)s_(1+2)and E_(2)s_(3)are higher than those in E_(3)d_(3)and E_(3)d_(2)L,basicall

关键词： Total organic carbon(TOC) Residual hydrocarbon generation potential(S_(2)) Geophysical prediction Seismic attribute Bozhong Sag Bohai Bay Basin

Tribological properties of laser cladding TiB_2 particles reinforced Ni-base alloy composite coatings on aluminum alloy

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Rare Metals 2015年第11期34卷 789-796页

作者： long He Ye-Fa Tan Xiao-long wang Qi-feng Jing xiang Hong College of Field Engineering PLA University of Science and Technology

To improve the wear resistance of aluminum alloy frictional parts, Ti B2particles reinforced Ni-base alloy composite coatings were prepared on aluminum alloy 7005 by laser cladding. The microstructure and tribological properties of the composite coatings were investigated. The results show that the composite coating contains the phases of Ni Al, Ni3Al, Al3Ni2, TiB2, TiB, TiC, CrB, and *** microhardness is HV0.5855.8, which is 15.4 % higher than that of the Ni-base alloy coating and is 6.7 times as high as that of the aluminum alloy. The friction coefficients of the composite coatings are reduced by 6.8 %–21.6 % and 13.2 %–32.4 % compared with those of the Ni-base alloy coatings and the aluminum alloys, while the wear losses are 27.4 %–43.2 % less than those of the Ni-base alloy coatings and are only 16.5 %–32.7 % of those of the aluminum alloys at different loads. At the light loads ranging from 3 to 6 N, the calculated maximum contact stress is smaller than the elastic limit contact stress. The wear mechanism of the composite coatings is micro-cutting wear, but changes into multi-plastic deformation wear at 9 N due to the higher calculated maximum contact stress than the elastic limit contact stress. As the loads increase to 12 N, the calculated flash temperature rises to 332.1 °*** composite coating experiences multi-plastic deformation wear, micro-brittle fracture wear, and oxidative wear.

关键词： Ti B2 Ni-base alloy Laser cladding Composite coati