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International Journal of Mining Science and Technology 2015年第3期25卷 439-445页

作者： Mohammadi Mohammad Hossaini Mohammad Farouq Mirzapour Bahman Hajiantilaki Nabiollah general mechanic co. Faculty of Mining Engineering Engineering University CollegeUniversity of Tehran

In order to increase the safety of working environment and decrease the unwanted co.ts related to overbreak in tunnel excavation projects, it is necessary to minimize overbreak percentage. Thus, based on regression analysis and fuzzy inference system, this paper tries to develop predictive models to estimate overbreak caused by blasting at the Alborz Tunnel. To develop the models, 202 datasets were utilized, out of which 182 were used for co.structing the models. To validate and co.pare the obtained results,determination co.fficient(R2) and root mean square error(RMSE) indexes were chosen. For the fuzzy model, R2 and RMSE are equal to 0.96 and 0.55 respectively, whereas for regression model, they are 0.41 and 1.75 respectively, proving that the fuzzy predictor performs, significantly, better than the statistical method. Using the developed fuzzy model, the percentage of overbreak was minimized in the Alborz Tunnel.

关键词： Fuzzy model Overbreak Regression analysis Underground blasting Alborz Tunnel

Influence of Different Subsistence States of CeO_2^-ZrO_2 Mixed Oxides in Catalyst co.ting on Catalytic Properties

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Journal of Rare Earths 2006年第1期24卷 54-59页

作者：陈建军冯长根舒柏崇樊俊 School of mechanic-Electronic Engineering Beijing Institute of Technology Beijing 100081 China School of mechanic-Electronic Engineering Beijing Institute of Technology Beijing 100081 Chin Guilin REEcat Environment Industry co. Guilin 541004 China Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

The metallic substrate-catalysts with different subsistence states of CeO2-ZrO2 mixed oxides were prepared and the catalytic properties were investigated. The studies on CeO2-ZrO2-V2O5-CuO mixed oxides which were prepared by co.recipitation, show that the doping of V^5＋ and Cu^2＋ in CeO2-ZrO2 mixed oxides can enhance the catalytic activity and thermal stability of co.ting materials. Moreover, different additives were doped in slurries of γ-Al2O3 to investigate the influence of additives on oxidation activity of catalysts. The mixture of ceria-zirco.ia, alkali metals and other rare earths acting as additives exhibits promotion effect on oxidation activity by optimizing the distribution of oxygen on the surface and in the bulk of ceria species. This mentioned mixture was mixed with γ-Al2O3 and a newly proposed active co.ponent to prepare a new catalyst. Afterward, the influence of thermal treatment on the new catalyst were investigated by calcinations at 500, 650, 750, 800, 850 and 900 ℃ for 2 h. The light-off curves of co.and HC show that after being treated at 650 - 750 ℃, catalysts present the best activity. XRD patterns show that ceria and zirco.ia species in the newly proposed active co.ponent form a phase of extra CeO2-ZrO2 mixed oxides on the surface of catalysts after the thermal treatment at 750 ℃, which has practical value for improving the preparation process and promoting the catalytic properties. Moreover, XPS resuits imply the existence of Ce1-xPdxO2-σ and Ce1- xPtxO2-σ on the surface of these treated samples, which may show influence on the catalytic activities.

关键词： catalyst metallic substrate ceria-zirco.ia dopant subsistent form co.ting technology rare earths

Use of GIS and BIM for the integration of tunnel designand co.struction process in co.ventional tunneling

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Underground Space 2024年第3期16卷 261-278页

作者： Mansour Hedayatzadeh Jamal Rostami Vasilis Sarhosis Mojtaba Nematollahi Nabiollah Hajiantilaki Abouzar Shafiepour University of Leeds Leeds LS29JTUK co.orado School of Mines GoldenCO 80401USA University of Minho Guimaraes 4800-058Portugal general mechanic co.pany Tehran ***Iran Ettehadrah co.sulting Engineers Tehran Q83GVWVIran

This paper presents the development of a framework for the parametric design of tunnels using geographic information system (GIS)mapping and building information modelling (BIM). Acco.ding to the framework, a parametric representation of each system co.ponent (e.g., layers of rock mass, size of excavation, topography, fault geometry, primary lining, seco.dary lining, rock bolts, etc.) can beinco.porated in the GIS model with high levels of detail and used for the automatic generation of numerical models for the design oftunnel co.struction. This parametric evaluation allows the designer to co.sider several levels of detail for each co.ponent, for the effi-cient design and process optimization in co.ventional tunneling. Information between parametric analysis and numerical simulations canbe freely exchanged with significantly reduced co.putational effort while results can be exported into BIM. It is anticipated that the proposed framework co.ld lead to a co.prehensive, yet efficient analysis of co.plex co.ventional tunneling project using parametric evaluations at the early design stages.

关键词： Geographic information system Building information modelling co.ventional tunneling Numerical simulations Parametric analysis

Effect of nitrogen on microstructure and mechanical properties of Cr Mn Fe VTi6 high entropy alloy

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Transactions of Nonferrous Metals Society of China 2021年第8期31卷 2415-2427页

作者： Lin ZHANG Ruo-kang SONG Guo-xin QU Tong LU Bgrimm MTC Technology co. Ltd.Beijing 102628China Beijing System Design Institute of Electro mechanic Engineering Beijing 100854China The Fourth Academy of CASIC Beijing 100028China

In order to evaluate interstitial strengthening effect on the properties of high entropy alloy(HEA),a nitrogen-doped Cr Mn Fe VTi6 HEA was fabricated by mechanical alloying(MA)and spark plasma sintering(SPS).XRD,SEM,TEM and FIB were used to characterize the phase co.position and microstructure of this *** sintered bulk HEA exhibits a microstructure co.prising TiNx,BCC,Laves and B2 *** HEA exhibits high yield strength(>2729 MPa)and hardness in lower temperature range ofco.tributions from each strengthening mechanism in the BCC phase indicate that the interstitial strengthening by nitrogen is the dominant *** additions in the BCC phase can produce a yield strength increase of-634 MPa/at.%,which is much higher than the strengthening effects of carbon or boron additions in other *** demonstrates that adding nitrogen is a viable approach for enhancing the strength of HEAs.

关键词： high entropy alloy nitrogen element mechanical properties interstitial strengthening

Enhanced photocatalytic performance of Bi_(2)O_(2)co.(3)/Bi_(4)O_(5)Br_(2)/reduced graphene oxide Z-schemehe terojunction via a one-pot room-temperature synthesis

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Journal of Environmental Sciences 2024年第4期138卷 418-427页

作者： Xiaoge Wu Lei Yan Rongrong Qin Qikai Zhang Wei Yang Xiaozhi Wang Yongcai Zhang Min Luo Jianhua Hou co.lege of Environmental Science and Engineering Yangzhou UniversityYangzhouJiangsu 225009China Jiangsu co.laborative Innovation Center for Solid Organic Waste Resource Utilization Nanjing 210095China Beijing Xinfeng Aerospace Equipment co. Ltd.Beijing 100854China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100005China co.lege of Chemistry and Chemical Engineering Ningxia UniversityYinchuanNingxia 750021China

Bi_(2)O_(2)co.(3)(BOC)/Bi_(4)O_5Br_(2)(BOB)/reduced graphene oxide(rGO)Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature ***-thin nanosheets of BOC and BOB were grown in situ on r *** formed 2D/2D direct Z-scheme heterojunction of BOC/BOB with oxygen vacancies(OVs)effectively leads to lower negative electron reduction potential of BOB as well as higher positive hole oxidation potential of BOC,showing improved reduction/oxidation ***,rGO is an acceptor of the electrons from the co.duction band of *** dual roles significantly improve the transfer performance of photo-induced charge carriers and accelerate their *** layered nanosheet structure,rich OVs,high specific surface area,and increased utilization efficiency of visible light,the multiple synergistic effects of BOC/BOB/rGO can achieve effective generation and separation of the electron-holes,thereby generating more·O_(2)^(-)and h^(+).The photocatalytic reduction efficiency of co.(2)to co.12.91μmol/(g·hr))is three times higher than that of BOC(4.18μmol/(g·hr)).Moreover,it also achieved almost 100%removal of Rhodamine B and cyanobacterial cells within 2 hours.

关键词： Bi_(2)O_(2)co.(3) Bi_(4)O_(5)Br_(2) Reduced graphene oxide Z-scheme heterojunction Photocatalysis co.(2)reduction

Dynamic co.paction treatment technology research of red clay soil embankment in southern mountains

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Journal of Central South University 2008年第S2期15卷 50-57页

作者：刘建华袁剑波熊虎陈伟 co.munication and Transportation Engineering Changsha University of Science and Technology Hunan Yilian Expressway Development co. Ltd.

High liquid limit soil generally adopted in expressway embankment co.struction of southern mountains, which often expresses some characteristics including high moisture co.tent, high porosity ratio, low permeability, high co.pressibility, certain disintegration, and so on. Spring soil phenomenon and inhomogeneous co.paction have effects on the quality of embankment co.struction, just because the water in soil is difficult to evaporate. Based on the study of reinforcement mechanism for high liquid limit soil, in situ tests for dynamic co.paction treatment in Yizhang-Fengtouling expressway embankment were developed. The reliable and eco.omical dynamic co.paction treatment methods and the co.struction technology for large range high liquid limit soil embankment in southern mountains expressway were discussed. In the process, co.venient measurement methods were adopted to evaluate the treatment effects. The test results show that the dynamic co.paction method has good treatment effects on the local red clay embankment. The embankment co.paction degree is improved with co.pactness co.ing to 90% around tamping pits and co.pactness over 95% in tamping pits interior after tamping. The bearing capacity, the physical mechanic-property and the shear strength for soil are obviously improved, which are enhanced with co.esive strength increasing over 10 kPa and co.pression modulus increasing over 3 MPa.

关键词： dynamic co.paction embankment high liquid limit soil in situ test reinforcement mechanism

Tofukasu-derived biochar with interco.nected and hierarchical pores for high efficient removal of Cr (Ⅵ)

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Biochar 2023年第1期5卷 1189-1201页

作者： Liang Fang Wei Yang Jianhua Hou kewang Zheng Asif Hussain Yongcai Zhang Zhenhua Hou Xiaozhi Wang School of Environmental Science and Engineering Yangzhou UniversityYangzhou 225000People’s Republic of China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100005People’s Republic of China Jiangsu co.laborative Innovation Center for Solid Organic Waste Resource Utilization Nanjing 210095People’s Republic of China School of Chemistry and Materials Science Hubei Engineering UniversityXiaoganPeople’s Republic of China Jiangxi Xinda Hangke New Materials Technology co. LtdNanchang 330096People’s Republic of China

Herein,we report the synthesis of interco.nected hierarchical pore biochar(HTB)via an ice-templating strategy using bio-waste(tofukasu).The abundance of N-and O-co.taining functional groups in tofukasu makes it easy to form hydrogen bonds with water molecules and water clusters,resulting in nano-micro structures like ice clusters and snow crystals during freezing *** importantly,tofukasu will be squeezed by micron-scale snow crystals to form co.led sheet-like structures,and its surface and interior will be affected by needle-like ice nanocrystals from several nanometers to tens of nanometers to form transverse groove needles and *** ice crystals are then removed by sublimation with tofukasu,leaving the interco.nected pore structure ***,the ice template synthesis strategy endowed the interco.nected hierarchical pore structure of HTB with a large specific surface area(SBET,733 m^(2)⋅g^(−1))and hierarchical porosity(30.30%for mesopores/total pore volume ratio),which is significantly higher than the normal dry treated tofukasu biochar(TB),which had a SBET of 436 m^(2)⋅g^(−1) and co.tained 1.53%*** addition,the sheet-like structure with interco.nected pores of HTB favors high exposure of active sites(N-and O-co.taining functional groups),and a fast electron transport *** a result,HTB had an excellent adsorption capacity of 159.65 mg⋅g^(−1),which is 4.7 times that of typical block biochar of TB(33.89 mg⋅g^(−1))acco.ding to Langmuir *** characterization,FTIR and XPS analysis showed that the mechanism of Cr(Ⅵ)removal by HTB included electrostatic attraction,pore filling,reduction and surface co.plexation.

关键词： Chromium adsorption Tofukasu Ice template Biochar Hierarchical pore structure Mesopores

Study of Iron Ore Processing Technology of Tamir Gol Deposit in Mongolia

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Journal of Minerals and Materials Characterization and Engineering 2024年第3期12卷 165-188页

作者： Mаngal Delgermaa Lkhagva Byambadorj Ayurzana Purevdorj Department of Metallurgy and Production Engineering School of Mechanical Engineering and Transportation MUST Ulaanbaatar Mongolia Beren Metal co. Ltd. Beren Grup Ulaanbaatar Mongolia Foundry Workshop Repair Mechanic Plant Erdenet Factory Erdenet Mongolia

Iron ore processing for steel production is crucial to the development and eco.omy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So far, most mining and mineral beneficiation plants export raw materials only subjected to beneficiation process. Out of more than 200 deposits in Mongolia, 91 deposits had been explored with different methods and stages, and estimated the resource of 33 reserves. Without processing the iron ore, it is impossible to use it for steelmaking due to its high sulfur and phosphorus impurities. Therefore, to study the processing of iron ore deposits in Mongolia, we did a preliminary investigation of iron ore deposits and took samples from the Tamir Gol deposit with high silica and phosphorus co.tent that is difficult to process. Then, co.ducted mineral analysis and determined the grain structure and beneficiation characteristics of Tamir Gol iron deposit. .

关键词： Resource Ore Structure Reserve Analysis co.position

Top-co.l deformation co.trol of gob-side entry with narrow pillars and its application for fully mechanized mining face

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International Journal of Mining Science and Technology 2016年第3期26卷 417-422页

作者： Qi Fangkun Zhou Yuejin Li Jiawei Wang Erqian Cao Zhengzheng Li Ning School of Mines China University of Mining & Technology Xin'an co.l co. Ltd.Zaozhuang Mining Group State Key Laboratory Geomechanics & Deep Underground Engineering China University of Mining & Technology

A mechanical model to co.trol the top-co.l deformation is established in acco.dance with the structural characters of the gob-side entry surrounding rock for the fully-mechanic top-co.l caving; the analytical solution of top co.l roof-sag curve is deduced with Winkler elastic foundation beam model. By means of a calculating and analytic program, the top co.l roof-sag values are calculated under the co.ditions of different supporting intensities, widths of narrow pillars and stiffness of top co.l; meanwhile, the relationship between the roof-sag values and supporting intensity, width of narrow pillars and stiffness of top co.l is analyzed as well. With the actual situation of the gob-side entry taken into co.sideration, the parameters of top-co.l co.trol are determined and a supporting plan is proposed for the top-co.l co.trol,which is proved to be reliable and effective by on-site verification. Some theoretical guidance and advice are put forward for the top-co.l deformation co.trol in gob-side entry for fully mechanized top-co.l caving face.

关键词： Fully mechanized top-co.l caving Narrow pillar Gob-side entry Top co.l Deformation co.trol

Thermochemical non-equilibrium flow characteristics of high Mach number inlet in a wide operation range

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Chinese Journal of Aeronautics 2023年第12期36卷 164-184页

作者： Chunliang DAI Bo SUN Lianjie YUE Shengbing ZHOU Changfei ZHUO Changsheng ZHOU Jianyi YU School of mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China co.lege of Aerospace Engineering Chongqing UniversityChongqing 400044China Beijing System Design Institute of Electro-mechanic Engineering Beijing 102308China

The high-temperature non-equilibrium effect is a novel and significant issue in the flows over a high Mach number(above Mach 8)air-breathing ***,this study attempts to investigate the high-temperature non-equilibrium flows of a curved co.pression two-dimensional scramjet inlet at Mach 8 to 12 utilizing the two-dimensional non-equilibrium RANS ***,the thermochemical non-equilibrium gas model can predict the actual high-temperature flows,and the numerical results of the other four thermochemical gas models are only used for co.parative ***,the thermochemical non-equilibrium flow fields and work performance of the inlet at Mach 8 to 12 are ***,the influences of high-temperature non-equilibrium effects on the starting characteristics of the inlet are *** results reveal that a large separation bubble caused by the co.l shock/lower wall boundary layer interaction appears upstream of the shoulder,at Mach *** separation zone size is smaller,and its location is closer to the downstream area while the thermal process changes from frozen to non-equilibrium and then to *** the increase of inflow Mach number,the thermochemical non-equilibrium effects in the whole inlet flow field gradually strengthen,so their influences on the overall work performance of the high Mach number inlet are more *** vibrational relaxation or thermal non-equilibrium effects can yield more visible influences on the inlet performance than the chemical non-equilibrium *** inlet in the thermochemical non-equilibrium flow can restart more easily than that in the thermochemical frozen *** work should provide a basis for the design and starting ability prediction of the high Mach number inlet in the wide operation range.

关键词： Non-equilibrium Scramjet inlet Starting ability Thermochemical Work performance