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Optimization and mechanism of gold-bearing sulfide flotation

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Rare Metals 2014年第3期33卷 363-368页

作者： Zhong-Mei Sun Chun-Bao Sun ji-zhen Wang Wan-Zhong Yin School of Civil and Environmental Engineering University of Science and Technology Beijing Zijin Research Institute of Mining and Metallurgy School of materials & Metallurgy Northeastern University College of Zi jin Mining Fuzhou University

In order to overcome the difficulty of extracting gold from gold-bearing sulfide ore by cyanide process flotation was adopted based on mineralogical analysis Mineralogy shows that gold particles are of superfine structure and mainly enclosed by sulfide ores. Primary gold-bearing sulfide ore is fine-grained pyrite and arsenopyrite. The paper describes the effects of ratios and dosage of activators and collectors on the recovery and grade of gold concentrate. A proper flotation flowsheet was then proposed based on experimental condition and closedcircuit test. The gold concentrate with the gold grade of25.14 g ton-1and the recovery of 86.94 % is obtained after one rougher, three cleaners, and four scavengers from fine grinding flotation process. Furthermore, the mechanisms of combined activators and combined collectors were studied by thermodynamic calculation, and structure-activity relationship of flotation reagent was also explained

关键词： Gold Pyrite Arsenopyrite Activator Combined reagent Flotation

Variable stars in the field of open cluster NGC 2126

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Research in Astronomy and Astrophysics 2009年第7期9卷 791-802页

作者： Shun-Fang Liu zhen-Yu Wu Xiao-Bin Zhang jiang-Hua Wu Jun ma Zhao-ji jiang jian-Sheng Chen Xu Zhou National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We report the results of a time-series CCD photometric survey of variable stars in the field of open cluster NGC 2126. In about a one square degree field covering the cluster, a total of 21 variable candidates are detected during this survey, of which 16 are newly found. The periods, classifications and spectral types of 14 newly discovered variables are discussed, which consist of six eclipsing binary systems, three pulsating variable stars, three long period variables, one RS CVn star, and one W Uma or δ Scuff star. In addition, there are two variable candidates, the properties of which cannot be determined. By a method based on fitting observed spectral energy distributions of stars with theoretical ones, the membership probabilities and the fundamental parameters of this cluster are determined. As a result, five variables are probably members of NGC 2126. The fundamental parameters of this cluster are determined as： metallicity to be 0.008 Z, age log（t） = 8.95, distance modulus （m - M）0 = 10.34 and reddening value E（B - V） = 0.55 mag.

关键词： open clusters: individual (NGC 2126) - stars: variables (general) - bina- ties: general

Reclosing Current Limiting for DC Line Faults in VSC-HVDC Systems

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Journal of Modern Power Systems and Clean Energy 2022年第4期10卷 1040-1049页

作者： Shunliang Wang Junjie Zhou ji Shu Tianqi Liu Junpeng ma College of Electrical Engineering Sichuan UniversityChengdu 610065China

The problem of reclosing current limiting in voltage source converter based high-voltage direct current(VSCHVDC)systems is becoming more and more serious.A soft reclosing scheme for DC permanent faults is presented in this *** the converter voltages of stations at both terminals of the disconnected faulty line may be different,the choice of which terminal to reclose first will affect the reclosing overcurrent.A method for selecting the terminal to reclose first is investigated to achieve a minimum peak overcurrent during the reclosing *** order to ensure that the hybrid DC circuit breaker(HDCCB)adapts to the needs of the reclosing process better,the traditional HDCCB is improved by adding a soft reclosing module(SRM).The energy dissipated in the arresters is significantly reduced when using the improved *** improved HDCCB will be able to reclose multiple times safely and thus increase the possibility of successful ***,the recovery time after the HDCCB is successfully reclosed is very short with the improved HDCCB and its control *** results show that this proposed scheme is capable of limiting the reclosing overcurrent when the fault still exists.

关键词： Soft reclosing current limiting voltage source converter based high-voltage direct current(VSC-HVDC) DC fault

Surface charge transfer doping of graphene using a strong molecular dopant CN6-CP

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Chinese Chemical Letters 2023年第3期34卷 553-556页

作者： Xiaojuan Dai Liyao Liu zhen ji Qing Meng Ye Zou Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Surface charge transfer doping of graphene plays an important role in graphene-based electronics due to its simplicity,high doping efficiency,and ***,we demonstrate the effective surface charge transfer hole doping of graphene by using a strong p-type molecular dopant hexacyanotrimethylene-cyclopropane (CN6-CP).The CN6-CP exhibits a very high intrinsic work function of 6.37 e V,which facilitates remarkable electron transfer from graphene to CN6-CP as revealed by in situ photoelectron spectroscopy ***,hole accumulation appears in the graphene layer at the direct contact with *** evidenced by Hall effect measurements,the areal hole density of graphene significantly increased from 8.3×10^(12)cm^(-2) to 2.21×10^(13)cm^(-2) upon 6 nm CN6-CP *** CN6-CP acceptor with strong p-doping effect has great implications for both graphene-based and organic electronics.

关键词： Graphene Surface charge transfer doping Molecular dopant CN6-CP Hall effect

Mechanisms Underlying the Biological WetAdhesion:Coupled Effects of Interstitial Liquid and Contact Geometry

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Journal of Bionic Engineering 2020年第3期17卷 448-456页

作者： jing Li Jun Liu Chuandong ma jiaxin ji jianlin Liu College of Mechanical and Electrical Engineering China University of Petroleum(East China)Qingdao 266580China College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao 266580China

Wet adhesion is widely adopted in biological adhesion systems in nature,and it is beneficial to design new materials with desired properties based on the underlying physics of wet *** aim of this work is to develop a design criterion to regulate the wet *** effects of different contact shapes(flat and sphere)and morphologies of the substrate(smooth,microstructure and nanostructure)on the adhesion force are *** with the theoretical models,the dominated factors in the separation process and isolating the viscous contributions from the capillary interactions are *** results demonstrate that the adhesion mechanisms depend significantly on the capillary numbers of the interstitial liquid and the contact geometry,and the ratio of capillary force to viscous force is a key to regulate the wet adhesion *** findings can not only explain some phenomena of wet adhesion to organisms,but also provide some inspirations to design new adhesion technology for robotic fingers that can grasp objects in wet environments.

关键词： wet adhesion capillary force viscous force adhesion mechanism

Thickness-Shear Frequencies of an Infinite Quartz Plate with Graded material Properties Across the Thickness

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Acta Mechanica Solida Sinica 2020年第3期33卷 361-367页

作者： Rongxing Wu Wenliang Zhang Tingfeng ma jianke Du ji Wang Piezoelectric Device Laboratory School of Mechanical Engineering and MechanicsNingbo University818 Fenghua RoadNingbo 315211ZhejiangChina Department of Architectural Engineering Ningbo Polytechnic1069 Xinda RoadBeilun DistrictNingbo 315800ZhejiangChina

For quartz crystal resonators of thickness-shear type,the vibration frequency and mode shapes reflect the basic material and structural properties of a quartz crystal plate and the variation with time under attack by erosive gases and liquids that can cause surface and internal degradation in a graded *** gradual effects,in turn,will change surface conditions through elastic constants and stiffness and more importantly the gradient of such properties across the thickness with certain *** we study the thickness-shear vibrations of functionally graded material plates with properties of the popular AT-cut quartz crystal varying across the thickness in a general pattern represented by both sine and cosine components of the *** vibration solutions are obtained through the Fourier expansion of the plate deformation.

关键词： Thickness-shear Frequency Vibration Functionally graded materials Resonator

Using a Gaussian mathematical model to define eruptive stages of young volcanic rocks in Tengchong based on laser 40Ar/39Ar dating

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Science China Earth Sciences 2020年第5期63卷 662-673页

作者： Xinwei ZHAO jing ZHOU Fang ma jianqing ji Alan DEINO School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China Berkeley Geochronology Center Berkeley CA94709USA

Reconstruction of Quaternary environments,late Cenozoic geodynamics and evaluation of volcanic hazards,all depend on the precise delineation of eruptive *** recent years,laser 40Ar/39Ar dating methods have been widely used for dating young volcanic rocks,given their stable automated testing process,very low background level and high sensitivity,which meet the requirements for precise dating of young *** paper applied high-precision laser 40Ar/39Ar dating to the main volcanic units in the Tengchong area and obtained ages in the range of 0.025–5.1 ma using conventional data processing ***,conventional dating highlighted issues related to very low radiogenic 40Ar content,accidental errors and poor data stability,which led to huge age ***,lacking a unified timescale,conventional methods were unable to strictly define the stages of the Tengchong volcanic eruptions,leading to ongoing *** this study,we applied a Gaussian mathematical model to deal with all 378 original ages from 13 *** apparent age-probability diagram,consisting of three independent waveforms,have been *** corresponding isochron ages of these three waveforms suggest there were three volcanic eruptive stages,namely during the Pliocene(3.78±0.04 ma),early Middle Pleistocene(0.63±0.03 ma)and late Middle Pleistocene to early Late Pleistocene(0.139±0.005 ma).These results accurately define eruptive stages in the Tengchong area.

关键词： Laser 40Ar/39Ar dating Gaussian mathematical model Eruptive stages Apparent age-probability diagram Age deviations Isochron age

The simultaneous improvements of strength and ductility in additive manufactured Ni-based superalloy via controlling cellular subgrain microstructure

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Journal of materials Science & Technology 2021年第9期68卷 184-190页

作者： Yanan Zhao Zongqing ma Liming Yu ji Dong Yongchang Liu State Key Lab of Hydraulic Engineering Simulation and Safety.School of materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Sino-German University of Applied Sciences TianjinChina

Fine cellular subgrain structure was formed in the Selective Laser Melting(SLM) manu factured IN718 alloy via optimizing the processing *** the subsequent homogenization heat treatment process,the Laves phase dispersed at the subgrain boundaries can be eliminated while the cellular subgrain structure is reserved in the printed samples after holding at 1080℃ for 50 *** the prolongation of the holding time,the subgrain boundaries undergo low angle rotation via the motion ofdislocation,which leads to the annihilation of the cellular subgrain ***,during the subsequent double aging heat treatment process,the reserved cellular subgrain structure in the homogenized samples promotes the precipitation of γ" second phase nanoparticles,and these precipitated γ" phase nanoparticles prefer to distribute at subgrain *** was found that these unique subgrain boundaries with γ" phase precipitates can hinder but not fully terminate the motion of dislocation during the plastic deformation process,which contributes to increasing the strength as well as holding the stable plastic ***,the strength and ductility of final prepared IN718 alloy with cellular subgrain microstructure were improved simultaneously compared to the prepared alloy without cellular subgrain structure,which even exceed the mechanical properties standards(AMS 5662) of wrought IN718 *** results in our work suggest that controlling the subgrain structure is a promising effective strategy to improve the mechanical properties of SLM manu factured nickel-based superalloy.

关键词： Selective laser melting Superalloy Subgrain structure Strengthening and toughening

Effects of the Wetting Particles on Phase Separation of Binary Mixtures

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Chinese Physics Letters 2000年第11期17卷 824-826页

作者： LIU ji-Wen ma Yu-Qiang National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093

We study phase separation of binary mixtures in the presence of mobile particles by the lattice Monte Carlo *** presence of mobile particles changes the morphology of the domain growth,in agreement with earlier experimental *** varying the wetting interaction strength,we can control the speed of phase separation,and find a critical wetting strength beyond which the growth of the domains slows *** propose a novel scaling function which describes the growth of the domain size L(t)as a function of *** suggests an applicable way to tune the speed of phase separation by the coupling between the phase decomposition and the mobile particle-wetting process.

关键词： strength separation phase