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Evidence from pseudomorphous β-quartz phenocryst for decompression of rock-forming and ore-forming processes in Shapinggou porphyry Mo deposit

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Science China Earth Sciences 2016年第5期59卷 1014-1024页

作者： he jun XU XiaoChun XIE QiaoQin FAN ZiLiang CheN TianHu School of Resources and Environmental Engineering Hefei University of Technology Laboratory for Nanomineralogy & Environmental Material Hefei University of Technology

The Shapinggou porphyry molybdenum(Mo) deposit, located in Jinzhai County, Anhui Province, China, is the largest in the Qinling-Dabie Mo Metallogenic Belt. The intrusive rocks in the Shapinggou Mo ore district formed in the Yanshanian can be divided into two stages based on zircon U-Pb dating and geochemical features. This study focuses on the late stage intrusions(quartz syenite and granite porphyry), which are closely genetically related to molybdenum mineralization. Petrographic observations identified two quartz polymorphs in the quartz syenite and granite porphyry, which were derived from the same magmatic sources and similar evolutionary processes. The quartzes were identified as a xenomorphic β-quartz within quartz syenite, while the quartz phenocrysts within the granite porphyry were pseudomorphous b-quartz, characterized by a hexagonal bipyramid crystallography. The pseudomorphous b-quartz phenocrysts within the granite porphyry were altered from b-quartz through phase transformation. These crystals retained b-quartz pseudomorph. Combined with titanium-inzircon thermometry, quartz phase diagrams, and granitic Q-Ab-Or-H_2O phase diagrams, it is suggested that the quartz syenite and granite porphyry were formed under similar magmatic origins, including similar depths and magmatic crystallization temperatures. However, the β-quartz within quartz syenite indicated that the crystallization pressure was greater than 0.7 GPa, while the original b-quartz within the granite porphyry was formed under pressures between 0.4 and 0.7 GPa. The groundmass of the granite porphyry which formed after the phenocryst indicated a crystallizing pressure below 0.05 GPa. This indicates that the granite porphyry was formed under repetitive and rapid decompression. The decompression was significant as it caused the exsolution of the ore-forming fluids, and boiling and material precipitation during the magmatic-fluid process. The volumetric difference during the phase transformation f

关键词： Porphyry Mo deposit Pseudomorphous β-quartz Decompression mechanism Rock-forming and ore-forming processes Shapinggou Mo deposit

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Adaptive Fuzzy Sliding Mode Controller with Nonlinear Observer for Redundant Manipulators Handling Varying External Force

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Journal of Bionic Engineering 2016年第4期13卷 600-611页

作者： jun he Minzhou Luo Qingqing Zhang Jianghai Zhao Linsen Xu Department of Automation School of Information Science of Technology University of Science and Technology of China HeJei 230026 China Institute of Advanced Manufactcturing and Technology Hefei Institute of Physical Science Chinese Academy of Sciences Changzhou 213164 China School of Mechanical and Electrical Engineering Hohai University Changzhou 213264 China School of Engineering Science University of Seience and Technology of China Hefei 230026 China

An Adaptive Fuzzy Sliding Mode Controller with Nonlinear Observer （AFSMCO） for the redundant robotic manipulator is proposed in this paper. This approach could achieve a precise trajectory tracking for a robot manipulator in the presence of uncertainties and disturbances. Primarily, a suitable observer using the recursive algorithm is presented for an accurate estima- tion of external disturbances caused by the varying external force. Secondly, the adaptive fuzzy logic is designed to approximate the parameters of the sliding mode controller （AFSMC） to avoid chattering in real time. Moreover, it is shown using the Lyapunov theory that the tracking error asymptotically converges to zero. Finally, the effectiveness of the proposed control approach and theoretical discussion are demonstrated by simulation results on a 7-1ink robot and tested on a 7-DOF manipulator platform.

关键词： fuzzy logic adaptive control redundant manipulators nonlinear observer

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An improved numerical model of ski-jump flood discharge atomization

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Journal of Mountain Science 2022年第5期19卷 1263-1273页

作者： LIAN Ji-jian ZHANG Shu-guang he jun-ling State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China School of Civil Engineering Tianjin UniversityTianjin 300350China

Atomizing rainfall caused by flood discharge of high dams poses a great threat to the safety of powerhouse and ecological *** an indispensable means,numerical calculation is widely used in the safety design of discharge *** distribution of rainfall intensity is closely related to the trajectory nappe shape,jet trajectory distances,the splashed water droplet diameter and its velocity,and the spatial distribution of downstream nappe *** this paper,an experimental result is used to verify the improved stochastic splash mathematical model under different bucket types and discharge conditions,and the sensitivity of downstream rainfall intensity distribution to the shape of trajectory nappe,discharge flow,spatial distribution of downstream nappe wind,and the corresponding relationship between the droplet diameter and its splashing velocity is *** results show that the calculation accuracy of downstream rainfall intensity distribution is significantly improved when the above factors are taken into *** is found that the bucket type and flood discharge rate play the greatest role in the rainfall intensity distribution,followed by the downstream nappe wind distribution,and finally the corresponding relationship between the diameter and velocity of splash ***,these factors should be considered comprehensively when the rainfall intensity distribution of flood discharge atomization is *** study can help us to understand the influence factors of flood discharge atomization more deeply and predict the distribution of flood discharge atomization rainfall intensity more accurately.

关键词： Flood discharge atomization Rainfall intensity distribution Numerical calculation Sensitivity analysis

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Inequalities for Eigenvalues of a System of Equations of Elliptic Operator in Weighted Divergence Form on Metric Measure Space

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Acta Mathematica Sinica,English Series 2020年第8期36卷 903-916页

作者： he jun SUN Da Guang CheN Xu Yong JIANG College of Science Nanjing University of Science and TechnologyNanjing 210094P.R.China Department of Mathematical Sciences Tsinghua UniversityBeijing 100086P.R.China

Let A be a symmetric and positive definite(1,1)tensor on a bounded domain Ω in an ndimensional metric measure space(R^n,,e^-φdv).In this paper,we investigate the Dirichlet eigenvalue problem of a system of equations of elliptic operators in weighted divergence form{LA,φu+α▽(divu)-▽φdivu]=-su,inΩ,u∣aΩ=0,where LA,φ=div(A▽(·))-(A▽φ,▽(·)),α is a nonnegative constant and u is a vector-valued *** universal inequalities for eigenvalues of this problem are ***,as applications of these results,we give some estimates for the upper bound of sk+1 and the gap of sk+1-sk in terms of the first k *** results contain some results for the Lam′e system and a system of equations of the drifting Laplacian.

关键词： Eigenvalue inequality elliptic operator in weighted divergence form metric measure space

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Two-weight Norm Inequalities for Local Fractional Integrals on Gaussian Measure Spaces

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Acta Mathematica Sinica,English Series 2022年第7期38卷 1203-1228页

作者： Bo Ning DI Qian jun he Dun Yan YAN School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049P.R.China School of Applied Science Beijing Information Science and Technology UniversityBeijing 100192P.R.China

In this paper,the authors establish the two-weight boundedness of the local fractional maximal operators and local fractional integrals on Gaussian measure spaces associated with the local *** precisely,the authors first obtain the two-weight weak-type estimate for the locala fractional maximal operators of orderαfrom L^(p)(v)to L^(q,∞)(u)with 1≤p≤qa A_(p,q,a)^(b') ,and then obtain the two-weight weak-type estimate for the local fractional *** addition,the authors obtain the two-weight strong-type boundedness of the local fractional maximal operators under a condition of(u,v)∈M_(p,q,a)^(6a+9√da^2) and the two-weight strong-type boundedness of the local fractional *** estimates are established by the radialization method and dyadic approach.

关键词： Local fractional integral local fractional maximal operator two-weight inequality Gaussian measure space

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Pion-induced K^* production with Σ^* baryon off proton target

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Communications in Theoretical Physics 2020年第11期72卷 74-79页

作者： Jie Xiang Xiao-Yun Wang Hao Xu jun he Lanzhou University of Technology Lanzhou 730050China Department of Physics Lanzhou University of TechnologyLanzhou 730050China Department of Applied Physics School of ScienceNorthwestern Polytechnical UniversityXi’an 710129China Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjingJiangsu 210097China

In this work,the reactionπ-p→K^*Σ^*is investigated with an effective Lagrangian *** contributions from the Born terms,including the s,t,and u channel,are considered,and the Regge model and the Feynman model are applied to treat the t-channel *** existing experimental data can be reproduced with the best-fittedχ^2 being 2.38 and 1.54 for the Feynman and Regge models,***,it is found that the contribution from the t channel is dominant in the *** contribution of the u channel is mainly distributed at backward angles,and the contribution from the s channel is small and *** the Feynman model,the contribution of the t-channel K exchange is much larger than the contribution of the K^*exchange,while in the Regge model the contribution of the t-channel K exchange is comparable to that of the K^**** about the differential crosssection of theπ-p→K^*Σ^*reaction is also presented,which is helpful for clarifying the role of the Regge *** current results suggest high-precision experimental measurements which can be performed at J-PARC and COMPASS.

关键词： effective Lagrangian approach Regge model hadron states

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In-depth analysis of the fatigue mechanism induced by inclusions for high-strength bearing steels

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International Journal of Minerals,Metallurgy and Materials 2021年第5期28卷 826-834页

作者： Chao Gu Wen-qi Liu jun-he Lian Yan-ping Bao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Department of Mechanical Engineering Aalto UniversityPuumiehenkuja 302150 EspooFinland

A numerical study of stress distribution and fatigue behavior in terms of the effect of voids adjacent to inclusions was conducted with finite element modeling simulations under different *** mechanisms were also analyzed *** results showed that the effects of inclusions on fatigue life will distinctly decrease if the mechanical properties are close to those of the steel *** the inclusions,which are tightly bonded with the steel matrix,when the Young’s modulus is larger than that of the steel matrix,the stress will concentrate inside the inclusion;otherwise,the stress will concentrate in the steel *** voids exist on the interface between inclusions and the steel matrix,their effects on the fatigue process differ with their positions relative to the *** void on one side of an inclusion perpendicular to the fatigue loading direction will aggravate the effect of inclusions on fatigue behavior and lead to a sharp stress *** void on the top of inclusion along the fatigue loading direction will accelerate the debonding between the inclusion and steel matrix.

关键词： inclusion high-strength bearing steel fatigue numerical study stress distribution

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Tuning heterogeneous microstructures to enhance mechanical properties of nano-TiN particle reinforced Haynes 230 composites by laser powder bed fusion

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Rare Metals 2024年第9期43卷 4548-4565页

作者： Wen-Jie Liu Hui Li Qian-Xing Yin he-jun Du School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Laser powder bed fusion(LPBF)is considered to be one of the most promising additive manufacturing technologies for producing components with geometries and high geometrical precision that are unattainable by traditional *** superalloy exhibits exceptional mechanical and high-temperature performances,rendering it a prime candidate for advanced aero-engine *** the high demand for LPBF-manufactured superalloys,the superalloy is one of the materials manufactured difficultly by LPBF due to their large laser absorptivity fluctuation,poor molten pool stability and sharp temperature ***,superalloys are characterized by severe pores,undesirable coarse columnar grains and poor mechanical *** this work,the effect of nano-TiN particles on defects,molten pool characteristics and microstructure and performance of the composites were *** 4.5 wt%TiN/Haynes230 samples exhibited exceptional nanohardness and elastic modulus with maximum values reaching 5.53 GPa and 240.03 GPa,*** superior mechanical properties were attributed to the combined effects of spatter and gas pore inhibition,grain refinement and duplex nanophases ***,the stability of molten pool was enhanced,and spatter was effectively suppressed by adding nano-TiN particles,while grain refinement and columnar to equiaxed transitions were ***,the matrix exhibited a high dislocation density due to a significant hindrance of dislocation movement caused by massive nano-phases(e.g.,TiN and M_(23)C_(6)),resulting in the formation of extensive dislocation tangles and *** work offers novel insights into the role of nanoparticles reinforced superalloy composites by LPBF.

关键词： Composites Laser powder bed fusion Molten pool characteristics Microstructure Mechanical properties

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Synthesis and microwave absorption property of nanostructured Ketjen black/Fe_(3)O_(4) core/shell particles

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Rare Metals 2022年第10期41卷 3351-3359页

作者： Jing An Chen-Yang Zhao Zi-jun he Xing Mu Shi-Hai Guo Li-Hong Xu jun he Dong-Liang Zhao Department of Functional Material Research Central Iron and Steel Research InstituteBeijing100081China

Nanostructured Ketjen black/Fe_(3)O_(4) core/shell particles have been prepared through a simple one-step hydrothermal *** microstructure analysis shows that the assynthesized composite particles display a typical core/shell structure:the Ketjen black is playing as the core,while a large number of Fe_(3)O_(4) nanoparticles are uniformly attaching to the surface of the Ketjen black and forming the *** investigation of the magnetic properties of the nanostructured Ketjen black/Fe_(3)O_(4) core/shell materials reveals that the as-synthesized composite is a typical soft ferromagnetism *** 40 wt%Ketjen black/Fe_(3)O_(4)-paraffin composites exhibit an excellent reflection loss value of-64.21 dB at a thickness of 2.00 mm,and the broadest effective bandwidth of 4.17 GHz at a thickness of1.50 *** work provides a brand-new type of magnetic carbon nanoparticles,defined as Ketjen black/Fe_(3)O_(4)core/shell particles,which are an excellent candidate for high-perform ance electromagnetic wave absorber materials.

关键词： composite material composites

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Enhanced formaldehyde sensitivity of two-dimensional mesoporous SnO_(2) by nitrogen-doped graphene quantum dots

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Rare Metals 2021年第6期40卷 1561-1570页

作者： Zhen-Lu Chen Ding Wang Xian-Ying Wang jun-he Yang School of Materials Science and Engineering University of Shanghai for Science&TechnologyShanghai 200093China

Formaldehyde(HCHO) is widely known as an indoor air pollutant,and the monitoring of the gas has significant ***,most HCHO sensing materials do not have low detection limits and operate at high ***,two-dimensional(2D) mesoporous ultrathin SnO_(2) modified with nitrogen-doped graphene quantum dots(N-GQDs) was *** N-GQDs/SnO_(2) nanocomposite demonstrated high efficiency for HCHO *** the addition of 1.00 wt%N-GQDs,the response(Ra/Rg) of SnO_(2) gas sensor increased from 120 to 361 at 60℃ for the detection of 10×10^(-6) *** addition,the corresponding detection limit was as low as 10×10^(-9).Moreover,the sensor exhibited excellent selectivity and stability for the detection of *** enhanced sensing performance was attributed to both the large specific surface area of SnO_(2) and electron regulation of ***,this study presents a novel HCHO sensor,and it expands the research and application potential of GQDs nanocomposites.

关键词： Nitrogen-doped graphene quantum dots Formaldehyde sensor Two-dimensional SnO_(2) Nanocomposites

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