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Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons

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Chinese Physics B 2019年第1期28卷 522-526页

作者： Caiyun Wang Shuang Lu Xiaodong Yu Haipeng Li Editorial Board of Journal of cumt China University of Mining and technology Xuzhou 221008 China School of Physical Science and technology China University of Mining and technology Xuzhou 221116 China Department of Mechanical engineering University of colorado at Boulder

We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications.

关键词： graphene nanoribbons(GNRs) thermal conductivity phonon spectrum surface functionalization molecular dynamics simulations

Optimum Approximate Solution of Herschel-Bulkley Fluid Formula

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Journal of China University of Mining and technology 2004年第2期14卷 123-126页

作者：徐桂云林学栋张永忠 School of Machantronic engineering cumt Xuzhou Jiangsu 221008 China School of Science CUMT Xuzhou Jiangsu 221008 China

During calculating the fluid resistence with Herschel-Bulkley formula, the deviation is very large in some regions. In order to decrease the deviation, the optimized parameters of approximate solution are obtained through mathematic analysis and 3-D optimization calculation. In the close region of relative radius of the core flow, the continuity of deviation is determined with the limit methods. By analysis, the results indicate that the deviation in the area around the discontinuous nodes is very large; the deviation is the function of fluid parameters, approximate solution parameters and the relative radius of the core flow. While the fluid parameters keep certain, the 3-D figures of the deviation are drawn. The slice plane is used to seek the extremums of multi-peaks surface; The optimized parameters of approximate formula make the approximate formula in the regions of the certain deviation. The available area of relative radius of the core flow increases by 43.2%. It is more valuable for the calculation of flow resistance in pipe transportation.

关键词： Herschel-Bulkley fluid flow resistance approximate solution equation mathematic analysis optimization calculation eviation

Experimental study of coal flow characteristics under mining disturbance in China

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International Journal of coal Science & technology 2022年第5期9卷 32-47页

作者： Lei Zhang Zihao Kan Cun Zhang Jun Tang State Key Laboratory of coal Resources and Safe Mining School of MinesChina University of Mining and TechnologyXuzhou 221116JiangsuChina School of Energy and Mining engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Safety engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

With annually increased coal mining depth,gas extraction becomes more and more *** gas extraction efect depends on coal seam permeability,which,in turn,is afected by many factors,including loading and unloading stresses and strains in the coal *** induce internal cracks,resulting in cleats and gas emission channels,the coal seam permeability permanently changes *** clarify the stress-induced efects on coal seam permeability,this survey summarized the available approaches used to link the stress path and seepage law in the coal body seepage law,which can be classifed into two design methods:single load variation and combined feld mining *** characterization methods used to observe the surface of coal samples and three-dimensional reconstruction include electron microscopy,CT scanning,and Nuclear Magnetic Resonance(NMR).According to the stress paths designed by the above two approaches,the seepage laws and similarities of three kinds of coal samples with the fractured structure were summarized in this *** following directions are recommended to study the seepage law of coal bodies with three kinds of fractured structures under ***,the stress path of the experimental coal body should be designed by the combined feld mining *** stressed environment of a deep coal seam is complicated,and the axial and confning pressures change ***,one cannot fully refect the real situation on-site by studying permeability evolution ***,during the coal seam mining,the stressed state changes from time to time,and the development of coal seam fractures is afected by *** studying the stress efect on seepage of coal samples,the fractured structure of coal samples should be ***,the available structural characterization methods of coal samples can be combined with the 3D printing technology,which would produce artifcial samples with the fractured structure characteristics of na

关键词： Stress loading and unloading Structural characterization Permeability Fracture structure Broken coal

Thermodynamic Analysis of Desulfurization of Fine coal by Electrochemical Reduction Flotation

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Journal of China University of Mining and technology 2003年第2期13卷 166-169页

作者：赵炜朱红张瑜 School of Chemical engineering and technology CUMTXuzhouJiangsu 221008China School of Science Northern Jiaotong UnlversityBeijing 100044China

Problems in desulfurization of coal by electrochemical reduction is analyzed and calculated. The result shows that 1 ) the △rGm function of the reaction of pyrite into FeS and the modifying reaction decreasing the oxygenous functions on coal surface is smaller than zero in a spontaneous reaction, and greater than zero in a non-spontaneous reaction; 2) the △rGm value can be adjusted by pH and the dosage of electrolyte to make it be greaterthan zero , which is favorable for the modifying reaction and useful for desulfurization of coal. The research has provided a theoretical foundation for determining reasonable technical parameters of desulfurization。

关键词： coal electrochemical reduction thermodynamics desulfurization

Research on surface Modification of 96 Al_2O_3 by Ni Ion Implantation

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Journal of China University of Mining and technology 2006年第3期16卷 261-265页

作者： WANG Xiao-hong SUN Zhi ZHU Xin WANG Zhen-zhong School of Materials Science and engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

A matrix of 96 Al2O3 ceramics was implanted with Ni ion of different dosages and energies using a MEVVA implanter. Then metallic structures of copper were made on the implanted ceramics, by using selective electroless copper plating. In addition, the characteristics and microstructure of the implanted layer were studied by using the SEM, RBS and XPS. The results show that： 1） the implanted Ni exits as Ni^2, Ni^2＋, and Ni^3＋ in the surface of Al2O3 and metal Ni particles precipitate on ceramics during implantation; 2） the concentration of Ni submits to the Gauss distribution along the direction of implantation on the surface of Al2O3 and high Ni concentration on the surface can be obtained if the Ni is implanted with low energy and a high dosage and 3） Ni ion implantation can activate the surface of Al2O3 and induce electroless copper plating on the ceramics.

关键词： ion implantation Al2O3ceramics Ni chemical states

Nanoscale Properties of Boric Acid

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Journal of China University of Mining and technology 2001年第1期11卷 76-79页

作者：马向东贾云萍谢玉江 Department of Mechanical and Electronical engineering CUMT

Nanoscale properties of boric acid were studied by using atomic force microscopy (AFM) and nanomechanical testing system. XPS was used to research on the transform behaviors of H 3BO 3 at different temperatures. The crystal structure, surface morphology, and mechanical properties of H 3BO 3 were described. The results show that H 3BO 3 has layered structure, and can be transformed to boron oxide at high temperature. In addition there are a lot of defects in H 3BO 3 crystal.

关键词： boric acid boron oxide AFM morphology mechanical properties

Application of Infrared Imaging for Determination of Acting Range of Bolt Support

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Application of Infrared Imaging for Determination of Acting ...

Land surface temperature retrieval from Landsat 8 data and validation with geosensor network

2007国际机械工程与力学会议

作者： Yongjun ZHANG Liqian AN Runhou REN Shimin FAN Nianjie MA Jianhui LI Yuanming JI School of Mechanics Architecture and Civil EngineeringCUMT Center of technology Lu'an Mining Group School of Safety and Resource engineering CUMT

Infrared thermography is used as a non-destructive, non-contact infrared sensing technique to determine the acting range of bolt support and to monitor the progressive damage processes and failure mechanisms of bolted rock specimens subjected to given static unconfined compressions. The physical model tests of thermal infrared （TIR） radiation detection are carried out, taking the parameters of specific bolted coal roadway in Lu’an Mining Group for numerical and physical modelling objects. It is discovered that: （1） the temporal sequential features of the model surface TIR radiation in the process of loading are related to the model deformation, and they show staged characteristics;（2） according to the TIR temperature （TIRT） increment distribution of the different parts of the bolted rock samples, the acting range of the single bolt and two bolts are determined. And the acting ranges are coincident with the numerically simulated results with ANSYS;（3） according to the TIRT increment distribution of the different parts of the model of bolted coal roadway;the common acting ranges of several bolts are determined tentatively. The acting ranges are consistent with the numerically simulated results with FLAC 3D . The theoretical guides have been provided for the bolt parameters design of spacing interval and array pitch.

关键词： Bolt support Infrared thermography Numerical simulation Physical model test

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Frontiers of Earth Science 2017年第1期11卷 20-34页

作者： Kun TAN Zhihong LIAO Peijun DU Lixin WU jiangsu Key Laboratory of Resources and Environment Information engineering China University of Mining and Technology Xuzhou 221116 China Key Laboratory for Satellite Mapping technology and Applications of State Administration of Surveying Mapping and Geoinformation of China Nanjing University Nanjing 210023 China

A method for the retrieval of land surface temperature （LST） from the two thermal bands of Landsat 8 data is proposed in this paper. The emissivities of vegetation, bare land, buildings, and water are estimated using different features of the wavelength ranges and spectral response functions. Based on the Planck function of the Thermal Infrared Sensor （TIRS） band 10 and band 11, the radiative transfer equation is rebuilt and the LST is obtained using the modified emissivity parameters. A sensitivity analysis for the LST retrieval is also conducted. The LST was retrieved from Landsat 8 data for the city of Zoucheng, Shandong Province, China, using the proposed algorithm, and the LST reference data were obtained at the same time from a geosensor network （GSN）. A comparative analysis was conducted between the retrieved LST and the reference data from the GSN. The results showed that water had a higher LST error than the other land-cover types, of less than 1.2℃, and the LST errors for buildings and vegetation were less than 0.75℃. The difference between the retrieved LST and reference data was about 1℃ on a clear day. These results confirm that the proposed algorithm is effective for the retrieval of LST from the Landsat 8 thermal bands, and a GSN is an effective way to validate and improve the performance of LST retrieval.

关键词： Land surface temperature (LST) split-win- dow algorithm emissivity Landsat 8

Rapid reactive synthesis of TiAl3 intermetallics by thermal explosion and its oxidation resistance at high temperature

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Progress in Natural Science:Materials International 2019年第4期29卷 447-452页

作者： Xinyang Jiao Xiaoping Cai Gao Niu Xuanru Ren Xueqin Kang Peizhong Feng School of Materials Science and engineering China University of Mining and Technology School of Chemical engineering and technology China University of Mining and Technology Research Center of Laser Fusion China Academy of Engineering Physics

Porous TiAl3intermetallics were synthesized from Ti-75 at.% A1 elemental powder mixtures using an energysaving and rapid reactive method of thermal explosion(TE).The results demonstrated that the actual temperature of the compact climbed rapidly from 673℃to 1036℃within 24 s,indicating that an obvious TE reaction occurred during sintering *** video graphs suggested that the TE in Ti-Al system behaved instant occurrence and overall heating whether from axial or radial *** silver wires and NaCl particles that pressed on the surface of the sample disappeared due to the heavy heat released during TE *** pure TiAl3phases were synthesized in TE products and the open porosity of 55.4% was easy to *** high-temperature treatment at 1000℃,large amounts of sintering-neck formed and then improved the compressive strength of porous ***,the mass gain curve of porous TiAl3intermetallics oxidized at 650℃for 120 h exhibited the parabolic oxidation rate *** analysis confirmed that the strong O 1 s peak was 531.4 eV which was the typical binding energy of ***,the excellent oxidation resistance of porous TiAl3foams would be considered as good candidate materials for prolonging the service life at high temperatures.

关键词： Porous materials Rapid synthesis TiAl3 intermetallics Thermal explosion Oxidation resistance