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China Welding 2022年第4期31卷 48-58页

作者： Wang Chenji Liu Song Zhu Hao Cao Zhilong dong shaokang School of Materials Science and Engineering Shijiazhuang TIEDAO UniversityShijiazhuang 050043China Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang 050043China

In this study,friction stir lap welding(FSLW)was performed for the welding test of 6061 aluminium alloy and T2 pure *** effect of process parameters containing rotation rate and travel speed on interfacial microstructure evolution and mechanical properties of Al/Cu dissimilar joints were *** experiments were carried out under the rotation rates of 600,900 and 1200 r/min and with the travel speeds of 30,70 and 100 mm/*** characteristic of interface transition zones(ITZs)and the species of intermetallic compounds(IMCs)were *** Al/Cu interface showed a layered structure composed of Al-Cu IMCs,which will affect the mechanical *** layer consisting of Al2Cu was formed at lower heat input,and as heat input increased the Al4Cu9 phase started to *** heat input will increase the thickness of the interface and raise the brittleness of the *** thickness of the IMCs layers changed from0.89μm to 3.96μm as the heat input *** maximum value of tensile shear loading of 4.65 kN was obtained at the rotation rate of900 r/min and travel speed of 100 mm/min with the interface thickness of 2.89μ*** fracture mode of the joints was a mix of ductile and brittle fracture.

关键词： friction stir lap welding Al/Cu dissimilar welding intermetallic compounds process parameters mechanical properties

Corrosion behavior of aluminum/steel dissimilar metals friction stir welding joint

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China Welding 2021年第3期30卷 20-30页

作者： Mo Shuxian dong shaokang Zhu Hao Jiao Yinan Wang Jun School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang 050043China School of Materials Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050018China

The corrosion performance of aluminum/steel contact and aluminum/steel FSW joint in 3.5 wt.%NaCl solution were analyzed using potentiostatic *** post-corrosion microstructure of the welding joint was characterized by optical microscope(OM),scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).The results showed that the localized corrosion of FSW joint of Al/steel dissimilar metals mainly initiated at the interface transition zone(ITZ).Precipitation of intermetallic compounds(IMCs)and Fe-rich phase particles in ITZ accelerated the corrosion of the FSW *** phenomenon has been attributed to distinct corrosion potentials between IMCs and steel,aluminum base *** corrosion resistance sequence of IMCs in ITZ is Fe_(3)Al>FeAl>Fe_(2)Al_(5).

关键词： aluminum/steel dissimilar metals joining corrosion behavior Intermetallic compounds

Strength mismatch mechanism on friction stir welding joint of 7075 aluminum alloy

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China Welding 2021年第1期30卷 30-36页

作者： Zhu Hao dong shaokang Zhao Yipeng Wang Chenji Wang Jun Zhu Shaojin School of Materials Science and Engineering Shijiazhuang TIEDAO UniversityShijiazhuang 050043China Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang 050043China School of Materials Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050018China China Petroleum Pipeline Engineering Co.LTD Langfang 065000China

The precipitated phases in the WNZ,TMAZ,HAZ and BM of the friction stir welding(FSW)joint were observed using the transmission electron microscopy(TEM)and the lattice fringe spacing of the precipitated phases was *** with X-ray diffraction(XRD),the types of precipitated phases among the joint were confirmed and then the strength mismatch mechanism was *** results show the precipitated phases of 7075 aluminum alloy FSW joint mainly consist of MgZn_(2),AlCuMg and Al_(2)*** microzone of the joint experienced different thermal cycles,the types and sizes of precipitated phases are different and the strengthening effect is *** strengthening effect of the AlCuMg and Al_(2)CuMg are better than that of MgZn_(2).The precipitated phase in the WNZ mainly includes AlCuMg and Al_(2)CuMg,as well as the grain size is fine,the microhardness in this zone is pretty *** number of precipitated phase AlCuMg and Al_(2)CuMg is smaller in the TMAZ and the MgZn_(2)is relatively more,which lead the microhardness *** number of precipitated phase MgZn_(2)is relative larger in the HAZ,as well as the grain coarsening,the microhardness in this zone is lowest of the *** the same time,there are the precipitate free zones(PFZ)among the 7075 aluminum alloy FSW joint,which decreases the microhardness of the whole joint to some extent.

关键词： 7075 aluminum alloy friction stir welding precipitated phase the precipitate free zones strength mismatch

Mechanical behaviours of bedded sandstone under hydromechanical coupling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1245-1261页

作者： Junwen Zhang Zhixiang Song Lichao Zhang shaokang Wu Shanyong Wang Yang Zhang Xukai dong Jinxin Wang Yanbo Han Baohua Kan School of Energy and Mining Engineering China University of Mining and Technology (Beijing)Beijing100083China Jarud Banner Zhahanao'er Coal Industry Co. Ltd.ZhaluteqiInner Mongolia029200China Priority Research Centre for Geotechnical Science & Engineering The University of NewcastleCallaghanNSW 2308Australia

The combination of the dipping effect and hydromechanical(H-M)coupling effect can easily lead to water inrush disasters in water-rich roadways with different dip angles in coal ***,H-M coupling tests of bedded sandstones under identical osmotic pressure and various confining pressures were ***,the evolution curves of stress-strain,permeability and damage,macro-and mesoscopic failure characteristics were ***,the mechanical behaviour was characterized,and finally the failure mechanism was *** results showed that:(1)The failure of the sandstone with the bedding angle of 45°or 60°was the structure-dominant type,while that with the bedding angle of 0°,30°or 90°was the force-dominant type.(2)When the bedding angle was in the range of(0°,30°)or(45°,90°),the confining pressure played a dominant role in influencing the peak ***,withinβ∈(30°,45°),the bedding effect played a dominant role in the peak strength.(3)With the increase in bedding angle,the cohesion increased first,then decreased and finally increased,while the internal friction angle was the opposite.(4)When the bedding angle was 0°or 30°,the“water wedging”effect and the“bedding buckling”effect would lead to the forking or converging shear *** the bedding angle was 45°or 60°,the sliding friction effect would lead to the shear slipping *** the bedding angle was 90°,the combination of the“bedding buckling”effect and shear effect would lead to the mixed tension-shear *** above conclusions obtained are helpful for the prevention of water inrush disasters in water-rich roadways with different dips in coal mines.

关键词： Hydromechanical coupling Bedded sandstones Mechanical behaviour Bedding effect Failure mechanism

Reinforcement Learning from Algorithm Model to Industry Innovation Innovation: A Foundation Stone of Future Artificial Intelligence

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ZTE Communications 2019年第3期17卷 31-41页

作者： dong shaokang CHEN Jiarui LIU Yong BAO Tianyi GAO Yang State Key Laboratory for Novel Software Technology Nanjing University

Reinforcement learning(RL)algorithm has been introduced for several decades,which becomes a paradigm in sequential decision-making and *** development of reinforcement learning,especially in recent years,has enabled this algorithm to be applied in many industry fields,such as robotics,medical intelligence,and *** paper first introduces the history and background of reinforcement learning,and then illustrates the industrial application and open source *** that,the successful applications from AlphaGo to AlphaZero and future reinforcement learning technique are focused ***,the artificial intelligence for complex interaction(e.g.,stochastic environment,multiple players,selfish behavior,and distributes optimization)is considered and this paper concludes with the highlight and outlook of future general artificial intelligence.

关键词： artificial intelligence decision-making and control problems reinforcementlearning

Causal relationship between circulating vitamin C and 25-hydroxyvitamin D concentrations and common mental disorders-a Mendelian randomization study

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Food Science and Human Wellness 2024年第4期13卷 1877-1885页

作者： Yuanyuan Wang Lirong dong Meng Zhao Shiyu Yin Pan Da Dengfeng Xu Yifei Lu Jiayue Xia Niannian Wang shaokang Wang Guiju Sun Key Laboratory of Environmental Medicine and Engineering of Ministry of Education and Department of Nutrition and Food HygieneSchool of Public HealthSoutheast UniversityNanjing 210009China Department of Integrated Service and Management Jiangsu Provincial Center for Disease Control and PreventionNanjing 210009China

Mental disorders seriously affect people’s health and social *** Mendelian randomization(MR)study was designed to investigate the causal relationship between circulating vitamin C(VC)or 25-hydroxyvitamin D(25(OH)D)levels and mental *** data used for the MR analysis were derived from the summary genome-wide association studies(GWAS)database for VC and 25(OH)D and from the Finn Gen consortium for fourteen mental *** on the inverse variance weighted(IVW)method,we found a potential causal association between circulating VC and anxiety disorders(IVW:OR=1.139,95%CI:1.023-1.269,P=0.018).However,no causal association was found between VC or 25(OH)D and other mental disorders(P>0.05).In the reverse MR analysis,individuals with Alzheimer’s disease was causally associated with higher concentrations of circulating VC(P=0.012),while individuals with anxiety disorders had a negative association between the concentrations of 25(OH)D(P=0.012).However,the current evidence does not support a causal relationship between VC or 25(OH)D and other mental *** addition,there was no causal association between circulating VC and 25(OH)D(P>0.05).Future studies are needed to confirm these findings and to elucidate the mechanisms of potential causality.

关键词： Circulating vitamin C 25-Hydroxyvitamin D Mental disorder Mendelian randomization

Highly selective growth of(6,5)single-walled carbon nanotubes from sigma phase alloy catalyst

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Nano Research 2024年第3期17卷 1999-2003页

作者： Liantao Xin Chen Ma Qianru Wu shaokang Liu Linhai Li Xiuyun Zhang Liu Qian Maoshuai He dong Li Fangqian Han Shulan Hao Lihu Feng Yahan Li Huaping Liu Lili Zhang Chang Liu Jin Zhang College of Chemistry and Molecular Engineering Qingdao University of Science and TechnologyQingdao 266042China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Physics Science and Technology Yangzhou UniversityYangzhou 225002China Center for Nanochemistry Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The chirality structure of a single-walled carbon nanotube(SWNT)strongly depends on the composition of catalyst used in the chemical vapor deposition *** this study,we develop a porous magnesia supported manganese-rhenium(MnRe/MgO)catalyst for chirality-selective synthesis of *** characterizations reveal that(6,5)tubes with a selectivity higher than 70%are grown from the Re-rich MnRe/MgO *** comparing the SWNT growth results with those of monometallic Mn or Re,the formation of sigma phase,an intermetallic compound occurring in transition-metal alloy systems,is revealed to be crucial for the dominant synthesis of(6,5)*** work not only extends the application of sigma phase alloy for catalytic synthesis of SWNTs,but also sheds lights on the growth of SWNTs with a high chirality selectivity.

关键词： single-walled carbon nanotubes sigma phase manganese-rhenium catalyst selective growth transition-metal alloy

镍中间层对铝/镁异种金属搅拌摩擦焊接头微观组织的影响

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焊接学报 2022年第12期43卷 84-89,I0008页

作者：董少康马宇航朱浩王晨霁曹志龙王军石家庄铁道大学石家庄050043 河北省交通工程与环境协同发展新材料重点实验室石家庄050043 河北科技大学石家庄050018

采用搅拌摩擦焊(friction stir welding,FSW),引入厚度为0.05 mm镍箔作为中间层,在焊接速度不变条件下,采用不同转速对厚度为4 mm的6061铝合金和AZ31镁合金进行平板对接,对接头进行系列微观组织表征及力学性能测试,探讨转速对接头中镍... 详细信息

采用搅拌摩擦焊(friction stir welding,FSW),引入厚度为0.05 mm镍箔作为中间层,在焊接速度不变条件下,采用不同转速对厚度为4 mm的6061铝合金和AZ31镁合金进行平板对接,对接头进行系列微观组织表征及力学性能测试,探讨转速对接头中镍颗粒分布状态,金属间化合物(intermetallic compounds,IMCs)种类与分布及接头强度的影响规律.研究结果表明:与未引入中间层接头相比,引入镍改变了铝/镁异种金属FSW接头焊核区(weld nugget zone,WNZ)中IMCs种类及分布,WNZ存在明显的镁合金与铝合金相间的带状组织,其上分布着絮状Al_(12)Mg_(17)、颗粒状Mg_(2)Ni、层状Al_(3)Mg_(2)及大小不一的镍箔颗粒;随着转速增加,镍箔颗粒分布愈加均匀,Al_(3)Mg_(2)数量相对减少,且脆性Al_(3)Mg_(2)由连续分布逐渐演变为断续分布;当转速为750 r/min时,接头抗拉强度达到最大值,与未引入中间层接头相比,引入镍中间层接头抗拉强度提高了56 MPa,达到镁合金的56.9%.

关键词：铝/镁异种金属搅拌摩擦焊镍箔中间层金属间化合物

分根灌溉下水氮耦合对草莓果实品质及产量的影响

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中国生态农业学报 2018年第5期26卷 657-667页

作者：董少康高凡郭家选沈元月张雨桐郑然农业应用新技术北京市重点实验室/北京农学院资源与环境系北京102206 北京林果业生态环境功能提升协同创新中心北京102206

本文采用盆栽分根固定干湿灌溉试验研究了水氮耦合对草莓果实品质及产量的影响。试验设置水分和氮肥2个因素,草莓根区设置湿润与干旱(A/B)两个区域,湿润一侧(A)全生育期内土壤相对含水量均为80%±5%,干旱一侧(B)土壤相对含水量设置为20%... 详细信息

本文采用盆栽分根固定干湿灌溉试验研究了水氮耦合对草莓果实品质及产量的影响。试验设置水分和氮肥2个因素,草莓根区设置湿润与干旱(A/B)两个区域,湿润一侧(A)全生育期内土壤相对含水量均为80%±5%,干旱一侧(B)土壤相对含水量设置为20%±5%(重度水分胁迫)、35%±5%(中度水分胁迫)、50%±5%(轻度水分胁迫)3个处理水平;施氮量设置0.5 g(N)×kg^(-1)(低氮)、0.75 g(N)×kg^(-1)(中氮)、1 g(N)×kg^(-1)(高氮)3个处理水平,对照处理(即常规生产模式,CK)A/B两区域均为80%±5%土壤相对含水量、中氮[0.75 g(N)×kg^(-1)]水平。研究结果表明:1)分根干湿灌溉显著减少了草莓全生育期灌溉水量,提高了草莓的水分利用效率(WUE),全生育期内干旱一侧(B)土壤相对含水量为20%±5%、35%±5%和50%±5%的水分处理总灌溉水量分别为14.77 L×株^(-1)、16.62 L×株^(-1)和18.47 L×株^(-1),较CK处理(24.62 L×株^(-1))分别减少40.0%、32.5%和25.0%;以中度水分胁迫中氮水平的草莓水分利用效率(WUE)最高,为13.55 g×L-1,较CK处理提高47.1%,而产量没有明显减少;耦合分根干湿灌溉和施氮处理,轻度水分胁迫中氮水平下草莓果实产量最高,较CK处理提高4.4%。2)从对草莓果实品质影响角度分析,中氮及中度水分胁迫处理的草莓果实中Vc含量、可溶性糖含量、有机酸含量和糖酸比分别比CK处理增加63.3%、12.5%、3.9%和8.3%。综合考虑不同水氮耦合处理对草莓果实品质、产量、水分利用效率及对农业环境安全的影响,以湿润一侧(A)保持土壤相对含水量为80%±5%、干旱一侧(B)保持土壤相对含水量为35%±5%,且0.75 g(N)×kg^(-1)施氮水平为设施草莓生产适宜的水肥管理模式。

关键词：草莓分根灌溉施氮量水氮耦合品质产量水分利用效率

不同灌溉模式下草莓对水分胁迫的生理响应研究

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灌溉排水学报 2021年第1期40卷 1-6页

作者：高凡郑然郭家选李玉中董少康沈元月李兴亮农业农村部华北都市农业重点实验室/北京农学院资源与环境系北京102206 北京林果业生态环境功能提升协同创新中心北京102206 中国农业科学院农业环境与可持续发展研究所北京100081 北京市农林科学院林业果树研究所北京100097

【目的】探究不同灌溉模式下草莓对水分胁迫的生理响应,确定草莓节水灌溉适宜模式。【方法】采用3种灌溉模式:充分灌溉(FI,CK)、分根灌溉(PRI)和亏缺灌溉(DI),PRI和DI模式下设置3个水分胁迫水平:轻度(LS)、中度(MS)和重度(SS),研究了不... 详细信息

【目的】探究不同灌溉模式下草莓对水分胁迫的生理响应,确定草莓节水灌溉适宜模式。【方法】采用3种灌溉模式:充分灌溉(FI,CK)、分根灌溉(PRI)和亏缺灌溉(DI),PRI和DI模式下设置3个水分胁迫水平:轻度(LS)、中度(MS)和重度(SS),研究了不同灌溉模式下水分胁迫对草莓叶片叶绿素量、光合与蒸腾速率、渗透调节物质和丙二醛(MDA)量的影响。【结果】DI与PRI灌溉模式下,草莓叶片叶绿素a(Chl a)和叶绿素b(Chl b)量都显著低于CK,且随着基质水分胁迫程度的加剧而呈下降趋势;与DI模式相比,PRI模式下草莓叶片叶绿素量相对较高;随着水分胁迫程度的增强,DI和PRI草莓叶片蒸腾速率下降幅度明显,分别为35.2%~44.7%和21.0%~47.0%,而净光合速率变化不明显;MS和SS水平下DI和PRI的水分利用效率(WUE)分别较CK高101.8%~117.9%和68.8%~149.8%;不同水分胁迫水平下,PRI草莓叶片脯氨酸(PRO)累积量显著高于CK(19.0%~26.0%),且在LS和MS水平下显著高于DI;PRI草莓叶片MDA累积量仅在SS水平下显著高于CK(30.2%),而DI草莓叶片MDA累积量在MS和SS水平下显著高于CK,分别为34.4%和56.4%。【结论】PRI模式草莓比DI模式具有更强的渗透调节能力和耐旱性,PRI-MS组合为草莓节水灌溉适宜模式。

关键词：草莓水分胁迫分根灌溉亏缺灌溉生理响应