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International Journal of Mining Science and Technology 2020年第1期30卷 55-61页

作者： Guorui Feng Pengfei Wang College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China

With the depletion of easily minable coal seams,less favorable reserves under adverse conditions have to be mined out to meet the market *** to some historical reasons,large amount of remnant coal was left *** such case history occurred with the remnant rectangular stripe coal pillars using partial extraction method at Guandi Mine,Shanxi Province,*** challenge that the coal mine was facing was that there is an ultra-close coal seam right under it with an only 0.8–1.5 m sandstone dirt band in *** simulation study was carried out to investigate the simultaneous recovery of upper remnant coal pillars while mining the ultra-close lower panel using longwall top coal caving(LTCC).The remnant coal pillar was induced to cave in as top coal in LTCC *** modelling shows that the coal pillars are the abutments of the stress arch structure formed within the overburden *** stability of overhanging roof strata highly depends on the stability of the remnant coal *** the gob development(roof strata cave-in)is intermittent with the cave-in of these coal pillars and the sandstone dirt ***3D numerical modelling shows that the multi-seam interaction has a significant influence on mining-induced stress environment for mining of lower *** pattern of the stress evolution on the coal pillars with the advance of the lower working face was *** is demonstrated that the stress relief of a remnant coal pillar enhances the caveability of the pillars and sandstone dirt band below.

关键词： Simulation Remnant coal pillars Ultra-close Dirt band Longwall top coal caving

A review of cavability evaluation in longwall top coal caving

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International Journal of Mining Science and Technology 2017年第6期27卷 907-915页

作者： Tien Dung Le Rudrajit Mitra Joung Oh Bruce Hebblewhite School of Mining Engineering The University of New South Wales Sydney NSW 2052 Australia

Longwall top Coal Caving has been considered as one of the most effective technologies for the extraction of underground thick coal seams. A large number of studies on the applicability of Longwall top Coal Caving into new mine sites have linked the success of its application to the geo mechanical understanding of the cavability of the top coal. The paper aims to improve the knowledge of the top coal cavability evaluation. A range of parameters that affect the top coal cavability were first identified. Afterward, a number of cavability assessment methods and classifications were reviewed. The result is important in that it assists researchers in developing an advanced and reliable tool for the top coal cavability evaluation.

关键词： Longwall top coal caving Cavability Numerical modelling Caving mechanism Caving classification

Formation mechanism of carbonate cemented zones adjacent to the top overpressured surface in the central Junggar Basin,NW China

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Science China Earth Sciences 2010年第4期53卷 529-540页

作者： YANG Zhi1,2,ZOU CaiNeng1,3,HE Sheng2,LI QiYan1,HE ZhiLiang3,WU HengZhi5,CAO Feng1,MENG XianLong4,WANG FuRong2 & XIAO Qilin21 State Key Laboratory of EOR,Research Institute of Petroleum Exploration & Development,PetroChina,Beijing 100083,China 2 Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan 430074,China 3 State Key Laboratory of EOR,Research Institute of Petroleum Exploration & Development,Petrochina,Beijing 100083,China 4 Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083,China 5 Southwest Branch Company,SINOPEC,Chengdu 610051,China State Key Laboratory of EOR Research Institute of Petroleum Exploration & Development PetroChina Beijing China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of Geosciences Wuhan China State Key Laboratory of EOR Research Institute of Petroleum Exploration & Development Petrochina Beijing China Southwest Branch Company SINOPEC Chengdu China Research Institute of Petroleum Exploration and Production SINOPEC Beijing China

Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin,NW *** carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that:(1) carbonate cements are composed dominantly of ferrocalcite,ferroan dolomite,and ankerite;(2) carbonate cements are formed under a high temperature circumstance in the subsurface,and organic fluid migration has an important effect on the formation of them;and(3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured *** suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological *** study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins,and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

关键词： carbonate cemented zones formation mechanism stable carbon and oxygen isotopic top overpressured surface central Junggar Basin coal-bearing strata

Comparisons of AGRI/FY-4A Cloud Fraction and Cloud top Pressure with MODIS/Terra Measurements over East Asia

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Journal of Meteorological Research 2019年第4期33卷 705-719页

作者： Tao WANG Jiali LUO Jinglin LIANG Baojian WANG Wenshou TIAN Xiaoyan CHEN Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000 Gansu Meteorological Bureau Lanzhou 730030

Fengyun-4 A(FY-4 A),the second generation of China’s geostationary meteorological satellite,provides high spatiotemporal resolution cloud products over East *** this study,cloud fraction(CFR)and cloud top pressure(CTP)products in August 2017 derived from the Advanced Geosynchronous Radiation Imager(AGRI)aboard FY-4 A(AGRI/FY-4 A)are retrospectively compared with those from the Moderate Resolution Imaging Spectroradiometer(MODIS)aboard Terra(MODIS/Terra)over East *** avoid possible errors in the comparison caused by the lower temporal coverage of MODIS/Terra products compared to that of AGRI/FY-4 A over the same region and to account for time lags between observations of the two instruments,we construct datasets of AGRI/FY-4 A CFR and CTP to match those of MODIS/Terra in each scan over East Asia in August *** show that the CFR and CTP datasets of the two instruments generally agree well,with the linear correlation coefficients(R)between CFR(CTP)data of 0.83(0.80)regardless of time *** longer time lags contribute to the worse consistency between CFR(CTP)data derived from observations of the two instruments in most cases,large CFR/CTP discrepancies do not always match with long time *** CFR discrepancies appear in the vicinity of the Tibetan Plateau(TP;28°–45°N,75°–105°E).These differences in the cloud detection by the two instruments largely occur when MODIS/Terra detects clear-sky while AGRI/FY-4 A detects higher values of CFR,and this accounts for 61%of the CFR discrepancy greater than 50%near the *** the case of CTP,the largest discrepancies appear in the eastern Iranian Plateau(IP;25°–45°N,60°–80°E),where there are some samples with long time lags(20–35 min)and fewer daily data samples are available for computing monthly means compared to other regions since there are many clearsky data samples there during the study period.

关键词： AGRI/FY-4A MODIS/Terra cloud fraction cloud top pressure

Probing the top quark flavor-changing couplings at CEPC

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Chinese Physics C 2019年第11期43卷 36-48页

作者： Liaoshan Shi Cen Zhang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We propose to study the flavor properties of the top quark at the future Circular Electron Positron Collider(CEPC) in *** systematically consider the full set of 56 real parameters that characterize the flavor-changing neutral interactions of the top quark,which can be tested at CEPC in the single top production *** with the current bounds from the LEP2 data and the projected limits at the high-luminosity LHC,we find that CEPC could improve the limits of the four-fermion flavor-changing coefficients by one to two orders of magnitude,and would also provide similar sensitivity for the two-fermion flavor-changing ***,CEPC could explore a large fraction of currently allowed parameter space that will not be covered by the LHC *** show that the c-jet tagging capacity at CEPC could further improve its sensitivity to top-charm flavor-changing *** a signal is observed,the kinematic distribution as well as the c-jet tagging could be exploited to pinpoint the various flavor-changing couplings,providing valuable information about the flavor properties of the top quark.

关键词： top quark flavor-changing neutral current lepton collider

Evaluation of Cloud top Height Retrievals from China’s Next-Generation Geostationary Meteorological Satellite FY-4A

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Journal of Meteorological Research 2019年第3期33卷 553-562页

作者： Zhonghui TAN Shuo MA Xianbin ZHAO Wei YAN Wen LU National University of Defense Technology

To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Moderate Resolution Imaging Spectroradiometer (MODIS) operational products from August to October 2017. Regarding CTHs from CloudSat, CALIPSO, and MODIS as truth, the results show that the performance of FY-4A CTH retrievals is similar to that of Himawari-8. Both FY-4A and Himawari-8 retrieve reasonable CTH values for single-layer clouds, but perform poorly for multi-layer clouds. The mean bias error (MBE) shows that the mean value of FY-4A CTH retrievals is smaller than that of Himawari-8 for single-layer clouds but larger for multi-layer clouds. For ice crystal clouds, both FY-4A and Himawari-8 obtain the underestimated CTHs. However, there is a tendency for FY-4A and Himawari-8 to overestimate the CTH values of CloudSat and CALIPSO mainly for low level liquid water clouds. The temperature inversion near the tops of water clouds may result in an overestimation of CTHs. According to the MBE change with altitude, FY-4A and Himawari-8 overestimate the CTHs mainly for clouds below 3 km, and the overestimation is slightly more apparent in Himawari-8 data than that in FY-4A values. As the cloud optical thickness (COT) increases, the CTH bias of FY-4A CTH retrievals gradually decreases. Two typical cases are analyzed to illustrate the differences between different satellites' CTH retrievals in detail.

关键词： FY-4A Himawari-8 CloudSat Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Moderate Resolution Imaging Spectroradiometer (MODIS) cloud top height (CTH)

Structure and deformation measurements of shallow overburden during top coal caving longwall mining

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International Journal of Mining Science and Technology 2017年第6期27卷 1081-1085页

作者： Li Sheng Fan Chaojun Luo Mingkun Yang Zhenhua Lan Tianwei Zhang Haifeng College of Mining Liaoning Technical University State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines Henan Polytechnic University State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Chengyi Coal Mine Inner Mongolia Yitai Coal Co.Ltd.

Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole photography technique and the seismic CT scanner technique, the deformation and failure of overlying strata of fully mechanized caving face in shallow coal seam were studied and the failure development of overburden was determined. Results show that the full view borehole photography can reveal the characteristics of strata, and the seismic CT scanner can reflect the characteristics of strata between the boreholes. The combined measurement technique can effectively determine the height of fractured and caved zones. The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106-110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.

关键词： top coal caving Shallow depth Overburden failure and deformation Full view borehole photography Seismic CT scanner

The Production of Pseudo Goldstone Boson in top Quark Rare Decay

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Communications in Theoretical Physics 2002年第5期38卷 566-570页

作者： HUANG Jin-Shu LU Gong-Ru Department of Physics Henan Nanyang Normal College Nanyang 473061 China Department of Physics Henan Normal University Xinxiang 453002 China

We calculate the flavor changing t → cπ0 decay in the framework of the topcolor assisted multiscaletechnicolor model. We find that (a) the branching ratio of t → cπ0 is insensitive to mπ, mπs and mπt, while it increasesquickly as ε increases; (b) for reasonable ranges of the parameters, the maximum of the branching ratio in this modelmay reach 7 × 10-6, seven orders larger compared to the one t → cH0 calculated in the standard model. This mightprovide an opportunity to detect the rare decay of the top quark in experiments.

关键词： branching ratio, rare decay of the top quark, pseudo Goldstone boson, technicolor

A New Type of REE Deposit Found in Clay Rock at the top of the Permian Emeishan Basalt in the Yunnan-Guizhou Area

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Acta Geologica Sinica(English Edition) 2020年第1期94卷 204-205页

作者： GONG Daxing HUI Bo DAI Zongming LAI Yang TIAN Enyuan Institute of Multipurpose Utilization of Mineral Resources Chinese Academy of Geological SciencesChengdu 610041China

Objective A set of REE-rich clay rocks is formed at the top of the Emeishan basalt in the eastern Yunnan-Western Guizhou area,accompanied by Nb,Zr,*** is a new type of REE deposit and has great resource *** paper intr... 详细信息

关键词： A New Type of REE Deposit Found in Clay Rock at the top of the Permian Emeishan Basalt in the Yunnan-Guizhou Area REE

SUSY-QCD Effects in top Quark Pair Production in Association with a Gluon at the ILC

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Communications in Theoretical Physics 2015年第8期64卷 166-170页

作者：张延明刘宁 Institute of Theoretical Physics Henan Normal University

Given the null results of searches for new physics at the LHC,we investigate the one-loop effects SUSY QCD in the process e^+e^-→tg at the ILC in Minimal Supersymmetric Standard Model(MSSM).We find that the relative SUSY-QCD corrections to the cross section of e^+e^-→ tg can maximally reach 6.5%(3.2%) at the ILC with (1/2)s= 1000 GeV when m__1= 313.4 GeV and m_g =500(1500) GeV.

关键词： top quark ILC QCD