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Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore

Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1922-1935页

作者： Feng Lin Xia-Ting Feng Shiping Li Xiao hai Jiuyu Zhang Xiangxin Su Tianyang Tong Jianchun Song Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China Benxi Longxin Mining corporation limited Benxi117000China

Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock *** paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron *** heating and reflection evolution characteristics of ore under different microwave parameters(antenna type,power,and working distance)were studied,and the optimal microwave parameters were ***,the ore was irradiated with the optimal microwave parameters,and the cracking effect of the ore under the action of the high-power open microwave was *** results show that the reflection coefficient(standing wave ratio)can be rapidly(<5 s)and automatically adjusted below the preset threshold value(1.6)as microwave irradiation is *** using a right-angle horn antenna with a working distance of 5 cm,the effect of automatic reflection adjustment reaches the best among other antenna types and working *** the working distance is the same,the average temperature of the irradiation surface and the area of the high-temperature area under the action of the two antennas(right-angled and equal-angled horn antenna)are basically the same and decrease with the increase of working *** optimal microwave parameters are:a right-angle horn antenna with a working distance of 5 ***,in further experiments,the optimal parameters were used to irradiate for 20 s and 40 s at a microwave power of 60 kW,*** surface damage extended 38 cm×30 cm and 53 cm×30 cm,respectively,and the damage extended to a depth of about 50 *** drilling speed was increased by 56.2%and 66.5%,respectively,compared to the case when microwaves were not used.

关键词： Microwave parameters High power Field experiment Mechanical mining

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Computer vision-aided DEM study on the compaction characteristics of graded subgrade filler considering realistic coarse particle shapes

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Railway Engineering Science 2024年第2期32卷 194-210页

作者： Taifeng Li kang Xie Xiaobin Chen Zhixing Deng Qian Su Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China Department of Civil Engineering Central South UniversityChangsha 410075China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

The compaction quality of subgrade filler strongly affects subgrade *** main objective of this research is to analyze the macro-and micro-mechanical compaction characteristics of subgrade filler based on the real shape of coarse ***,an improved Viola-Jones algorithm is employed to establish a digitalized 2D particle database for coarse particle shape evaluation and discrete modeling purposes of subgrade *** indexes of 2D subgrade filler are then computed and statistically ***,numerical simulations are performed to quantitatively investigate the effects of the aspect ratio(AR)and interparticle friction coefficient(μ)on the macro-and micro-mechanical compaction characteristics of subgrade filler based on the discrete element method(DEM).The results show that with the increasing AR,the coarse particles are narrower,leading to the increasing movement of fine particles during compaction,which indicates that it is difficult for slender coarse particles to inhibit the migration of fine ***,the average displacement of particles is strongly influenced by the AR,indicating that their occlusion under power relies on particle *** dis-placement and velocity of fine particles are much greater than those of the coarse particles,which shows that compaction is primarily a migration of fine *** the cyclic load,the interparticle friction coefficientμhas little effect on the internal structure of the sample;under the quasi-static loads,however,the increase inμwill lead to a significant increase in the porosity of the *** study could not only provide a novel approach to investigate the compaction mechanism but also establish a new theoretical basis for the evaluation of intelligent subgrade compaction.

关键词： Subgrade filler particles Deep learning particle Shape analysis Particle library Compaction characteristics Discrete element method(DEM)

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Unraveling engineering disturbance effects on deformation in red-bed mudstone railway cuttings:incorporating crack-facilitated moisture diffusion

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Journal of Mountain Science 2024年第5期21卷 1663-1682页

作者： HUANG kang DAI Zhangjun YAN Chengzeng YAO Junkai CHI Zecheng CHEN Shanxiong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China Faculty of Engineering China University of GeosciencesWuhan 430074China International Joint Research Center for Deep Earth Drilling and Resource Development China University of GeosciencesWuhan 430074China China Academy of Railway Sciences corporation limited Beijing 100081China

Red-bed mudstone, prevalent in southwest China, poses a formidable challenge due to its hydrophilic clay minerals, resulting in expansion, deformation, and cracking upon exposure to moisture. This study addresses uplift deformation disasters in high-speed railways by employing a moisture diffusion-deformation-fracture coupling model based on the finite-discrete element method(FDEM). The model integrates the influence of cracks on moisture diffusion. The investigation into various excavation depths reveals a direct correlation between depth and the formation of tensile cracks at the bottom of the railway cutting. These cracks expedite moisture migration, significantly impacting the temporal and spatial evolution of the moisture field. Additionally, crack expansion dominates hygroscopic deformation, with the lateral coordinate of the crack zone determining peak vertical displacement. Furthermore, key factors influencing deformation in railway cuttings, including the swelling factor and initial moisture content at the bottom of the cutting, are explored. The number of tensile and shear cracks increases with greater excavation depth, particularly concerning shear cracks. Higher swelling factors and initial moisture contents result in an increased total number of cracks, predominantly shear cracks. Numerical calculations provide valuable insights, offering a scientific foundation and directional guidance for the precise prevention, control, prediction, and comprehensive treatment of mudstone-related issues in high-speed railways.

关键词： Red-bed mudstone Railway cutting FDEM Moisture diffusion Deformation Crack

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Nucleic acid-based diagnostics for infectious diseases in public health affairs

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Frontiers of Medicine 2012年第2期6卷 173-186页

作者： Albert Cheung-Hoi Yu Greg Vatcher Xin Yue Yan Dong Mao Hua Li Patrick H.K.Tam Parker Y.L.Tsang April K.Y.Wong Michael H.K.Hui Bin Yang Hao Tang Lok-Ting Lau Neuroscience Research Institute/Department of Neurobiology School of Basic Medical Sciences/Key Laboratory for NeuroscienceMinistry of Education/Key Laboratory for NeuroscienceMinistry of HealthPeking UniversityBeijing 100191China hai kang life corporation limited Hong Kong SARChina and Beijing 100176China

Infectious diseases,mostly caused by bacteria and viruses but also a result of fungal and parasitic infection,have been one of the most important public health concerns throughout human *** first step in combating these pathogens is to get a timely and accurate diagnosis at an affordable *** kinds of diagnostics have been developed,such as pathogen culture,biochemical tests and serological tests,to help detect and fight against the causative agents of ***,these diagnostic tests are generally unsatisfactory because they are not particularly sensitive and specific and are unable to deliver speedy *** acid-based diagnostics,detecting pathogens through the identification of their genomic sequences,have shown promise to overcome the above limitations and become more widely adopted in clinical *** we review some of the most popular nucleic acid-based diagnostics and focus on their adaptability and applicability to routine clinical *** also compare and contrast the characteristics of different types of nucleic acid-based diagnostics.

关键词： nucleic acid-based diagnostics infectious disease PCR NASBA LAMP microarray LOAC public health affairs

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Mechanism of Mg2+ dissolution from olivine and serpentine: Implication for bioleaching of high-magnesium nickel sulfide ore at elevated pH

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International Journal of Minerals,Metallurgy and Materials 2019年第9期26卷 1069-1079页

作者： Jian-zhi Sun Jian-kang Wen Bo-wei Chen Biao Wu National Engineering Laboratory of Biohydrometallurgy GRINM Group Corporation Limited

To inhibit the dissolution of Mg^2+ during the bioleaching process of high-magnesium nickel sulfide ore, the effect of major bioleaching factors on the dissolution of Mg^2+ from olivine and serpentine was investigated and kinetics studies were carried out. The results indicated that the dissolution rate-controlling steps are chemical reaction for olivine and internal diffusion for serpentine. The most influential factor on the dissolution of Mg^2+ from olivine and serpentine was temperature, followed by p H and particle size. A novel method of bioleaching at elevated pH was used in the bioleaching of Jinchuan ore. The results showed that elevated pH could significantly reduce the dissolution of Mg^2+ and acid consumption along with slightly influencing the leaching efficiencies of nickel and cobalt. A model was used to explain the leaching behaviors of high-magnesium nickel sulfide ore in different bioleaching systems. The model suggested that olivine will be depleted eventually, whereas serpentine will remain because of the difference in the rate-controlling steps. Bioleaching at elevated pH is a suitable method for treating high-magnesium nickel sulfide ores.

关键词： olivine serpentine high-magnesium nickel sulfide ore bioleaching shrinking core model elevated pH

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Erratum to:Unraveling engineering disturbance effects on deformation in red-bed mudstone railway cuttings:incorporating crack-facilitated moisture diffusion

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Journal of Mountain Science 2024年第8期21卷 2870-2870页

Erratum to:***.(2024)21(5):1663-1682 https://***/10.1007/s11629-023-8561-0 During the production process,the first author’s name was wrongly written as“Rang Huang”in the *** correct name for the first author is“Ka... 详细信息

关键词： moisture mudstone diffusion

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Online Intrusion Detection Mechanism Based on Model Migration in Intelligent Pumped Storage Power Stations

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China Communications 2023年第4期20卷 368-381页

作者： Yue Zong Yuanlin Luo Yuechao Wu Jiande Huang Bowen Yang Xiaoyu kang Shumei Liu Yao Yu Power China Huadong Engineering corporation limited Hangzhou 311122China East China Tongbai Pumped Storage Power Generation Co. LtdTaizhou 317200China School of Computer Science and Engineering Northeastern UniversityShenyang 110169China

With the continuous integration of new energy into the power grid,various new attacks continue to emerge and the feature distributions are constantly changing during the deployment of intelligent pumped storage power *** intrusion detection model trained on the old data is hard to effectively identify new attacks,and it is difficult to update the intrusion detection model in time when lacking *** solve this issue,by using model-based transfer learning methods,in this paper we propose a convolutional neural network(CNN)based transfer online sequential extreme learning machine(TOS-ELM)scheme to enable the online intrusion detection,which is called CNN-TOSELM in this *** our proposed scheme,we use pre-trained CNN to extract the characteristics of the target domain data as input,and then build online learning classifier TOS-ELM to transfer the parameter of the ELM classifier of the source *** results show the proposed CNNTOSELM scheme can achieve better detection performance and extremely short model update time for intelligent pumped storage power stations.

关键词： transfer learning intrusion detection online classification

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Performances of lithium manganese oxide prepared by hydrothermal process

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Journal of Central South University 2014年第4期21卷 1279-1284页

作者：孔龙李运姣张鹏黄海花叶万奇李春霞 School of Metallurgy and Environment Central South University Citic Dameng Mining Industries limited Changsha Research Institute of Mining and Metallurgy corporation limited

A simple hydrothermal process followed by heat treatment was applied to the preparation of spinel Li1.05Mn1.95O4. In this process, electrolytic manganese dioxide(EMD) and LiOH·H2O were used as starting materials. The physiochemical properties of the synthesized samples were investigated by thermogravimetry-differential scanning calorimetry(TG-DSC), X-ray diffractometry(XRD), and scanning electronic microscopy(SEM). The results show that the hydrothermally synthesized precursor is an essential amorphous. The precursor can be easily transferred to spinel powders with a homogeneous structure and a regularly-shaped morphology by heat treatment. Li1.05Mn1.95O4 powder obtained by heat treating the precursor at 430 °C for 12 h and then calcining at 800 °C for 12 h shows an excellent cycling performance with an initial charge capacity of 118.2 mA·h·g-1 obtained at 0.5C rate and 93.8% of its original value retained after 100 cycles.

关键词：水热法锰酸锂差示扫描量热法扫描电子显微镜表演制备电解二氧化锰 TG-DSC

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A novel flotation scheme: selective flotation of tungsten minerals from calcium minerals using Pb–BHA complexes in Shizhuyuan

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Rare Metals 2017年第6期36卷 533-540页

作者： hai-Sheng Han Wen-Li Liu Yue-Hua Hu Wei Sun Xiao-Dong Li School of Mineral Processing and Bioengineering Central South University Hu Nan Shizhuyuan Non-ferrous Metal limited Liability corporation

The similar floatabilities of calcium minerals and the huge difference between scheelite and wolframite have resulted in difficulties during their separation by flotation in Shizhuyuan Mine. In this study, novel collectors, lead complexes of benzohydroxamic acid（Pb-BHA）,were introduced to modify the surface properties of scheelite and wolframite, thereby effectively and selectively improving floatability. The Pb-BHA complexes are found to be selective for the separation of scheelite and calcium minerals with little use of depressants and enable the synchronous flotation of scheelite and ***, a novel flotation process was developed for the recovery of tungsten minerals. The process is simplified greatly, and the recovery is improved by almost 10%.Removing or decreasing the amount of water glass contributes to the improvement of tungsten and fluorite recovery and the circulation of water and reagents, which benefits the environment.

关键词： Tungsten minerals Flotation Calciumminerals Benzohydroxamic acid complexes Water glass

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Pore structure evolution during the coke graphitization process in a blast furnace

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1226-1233页

作者： Hao-bin Zhu Wen-long Zhan Zhi-jun He Ying-chang Yu Qing-hai Pang Jun-hong Zhang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China Ansteel Engineering Technology corporation limited Anshan 114021China

Pore structure is an important factor influencing coke strength,while the property of coke is essential to maintaining gas and liquid permeability in a blast ***,an in-depth understanding of the pore structure evolution during the graphitization process can reveal the coke size degradation behavior during its descent in a blast *** graphitization was simulated at different heating temperatures from 1100 to 1600℃ at intervals of 100℃.The quantitative evaluation of the coke pore structure with different graphitization degree was determined by vacuum drainage method and nitrogen adsorption *** show that the adsorption and desorption curves of graphitized coke have intersection points,and the two curves did not coincide,instead forming a“hysteresis loop.”Based on the hysteresis loop analysis,the porous structure of the graphitized coke mostly appeared in the shape of a“hair follicle.”Furthermore,with an increase in heating temperature,the apparent porosity,specific surface area,total pore volume,and amount of micropores showed good correlation and can divided into three stages:1100-1200,1200-1400,and 1400-1600℃.When the temperature was less than 1400℃,ash migration from the inner part mainly led to changes in the coke pore *** the temperature was greater than 1400℃,the pore structure evolution was mainly affected by the coke graphitization *** results of scanning electron microscopy,energy dispersive spectrometry,and ash content analyses also confirmed that the migration of the internal ash to the surface of the matrix during the graphitization process up to 1400℃ contributed to these changes.

关键词： coke blast furnace graphitization pore structure ash migration

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