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| 1 | Numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses显示文摘The pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of CT scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were developed.The 3D finite element models of the rock media with varied porosities were established based on the CT image processing of the physical models and the MIMICS software platform.The failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation theory.The dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were analyzed.It is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element models.With applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.The deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around pores.Shear stresses lead to microplasticity,while tensile stresses result in cracking of the matrix.Cracking and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold values.The simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical tests.The present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster mechanisms of rock media. | JU Yang1,2,WANG HuiJie1,YANG YongMing1,HU QinAng3 & PENG RuiDong1 1 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China University of Mining and Technology,Beijing 100083,China 2 Department of Mechanical and Manufacturing Engineering,University of Calgary,Calgary,Alberta,T2N 1N4,Canada 3 School of Environment and Civil Engineering,College of Engineering,Oklahoma State University,Stillwater,OK 74078,USA | 2010 | Science China(Technological Sciences)2010，53，4： | 32 |
| 2 | Energy analysis for damage and catastrophic failure of rocks显示文摘The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of energy.The main scope and the achievable objectives of the energy-based research system were expatiated.It was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy dissipation.It was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak load.For both hard and soft rocks,the energy dissipated after peak load accounts for a greater proportion.More energy would be required for rock failure under equal biaxial compression than under unequal biaxial compression.The total absorbed energy is different for rock failure under high-rate loading and low-rate loading.More fragmented failure pattern usually corresponds to higher energy absorption.The mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt rock.The energy accumulation,transfer,dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics theory.Furthermore,the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated numerically.It was demonstrated that energy is likely to be released from the weakest surface under compression,which triggers the global failure of rocks. | XIE HePing 1,2,LI LiYun 2,1,JU Yang 2,PENG RuiDong 2 & YANG YongMing 2 1 Sichuan University,Chengdu 610065,China 2 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China University of Mining and Technology,Beijing 100083,China | 2011 | Science China(Technological Sciences)2011，54，S1： | 29 |
| 3 | Geochemistry and mineralogy of the Late Permian coals from the Songzao Coalfield, Chongqing, southwestern China显示文摘Mineralogy and geochemistry of the four main workable coal seams (No.6, No.7, No.8, and No.11) of Late Permian age from the Songzao Coalfield, Chongqing, Southwest China, were examined using in- ductively coupled plasma-mass spectrometry (ICP-MS), X-ray fluorescence spectrometry (XRF), cold-vapor absorption spectrometry (CV-AAS), ion-selective electrode (ISE), scanning electron mi- croscopy equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), and X-ray diffraction analysis (XRD). The results showed that the main workable No.8 Coal that accounts for about 60% of the total coal reserves in the Songzao Coalfield was not enriched in hazardous trace elements. The No.11 Coal has high concentrations of alkaline elements, Be (9.14 μg/g), Sc (12.9 μg/g), Ti (9508 μg/g), Mn (397 μg/g), Co (23.7 μg/g), Cu (108 μg/g), Zn (123 μg/g), Ga (32 μg/g), Zr (1304 μg/g), Nb (169 μg/g), Hf (32.7 μg/g), Ta (11.4 μg/g), W (24.8 μg/g), Hg (0.28 μg/g), Pb (28.1 μg/g), Th (24.1 μg/g), and rare earth elements (509.62 μg/g). The concentration of Nb and Ta in the No. 11 Coal is higher than the industrial grade, and their potential utilization should be further studied. Besides pyrite, quartz, calcite, and clay minerals, trace minerals including chalcopyrite, marcasite, siderite, albite, mixed-layer clay minerals of illite and smectite, monazite, apatite, anatase, chlorite, and gypsum were found in the No.11 Coal. It should be noted that alabandite of hydrothermal origin and anatase occurring as cement were identi- fied in coal. In addition, the clayey microbands derived from alkaline volcanic ashes were identified in the coal. The dominant compositions of these clayey microbands were mixed-layer clay minerals of illite and smectite, which were interlayered with organic bands. The modes of occurrence of alkaline volcanic ash bands indicate that the volcanic activities were characterized by the multiple eruptions, short time interval and small scale for each eruption during peat accumulation. The alkaline volcanic ashes were the dominant factors for the enrichment of alkaline elements, Nb, Ta, Zr, Hf, and rare earth elements, and the sulfide minerals are the main carriers of Ga, Cu, and Hg in the No. 11 Coal. | DAI ShiFeng1,2, ZHOU YiPing3, REN DeYi1, WANG XiBo1, 2, LI Dan1, 2 & ZHAO Lei1, 2 1 State Key Laboratory of Coal Resources and Safe Mining (China University of Mining and Technology), Beijing 100083, China 2 Department of Resources and Earth Science, China University of Mining and Technology, Beijing 100083, China 3 Kunming Research Institute of Coal Science, Kunming 650041, China | 2007 | Science China Earth Sciences2007，50，5： | 27 |
| 4 | A statistical model for porous structure of rocks显示文摘The geometric features and the distribution properties of pores in rocks were in- vestigated by means of CT scanning tests of sandstones. The centroidal coordi- nates of pores, the statistic characterristics of pore distance, quantity, size and their probability density functions were formulated in this paper. The Monte Carlo method and the random number generating algorithm were employed to generate two series of random numbers with the desired statistic characteristics and prob- ability density functions upon which the random distribution of pore position, dis- tance and quantity were determined. A three-dimensional porous structural model of sandstone was constructed based on the FLAC3D program and the information of the pore position and distribution that the series of random numbers defined. On the basis of modelling, the Brazil split tests of rock discs were carried out to ex- amine the stress distribution, the pattern of element failure and the inosculation of failed elements. The simulation indicated that the proposed model was consistent with the realistic porous structure of rock in terms of their statistic properties of pores and geometric similarity. The built-up model disclosed the influence of pores on the stress distribution, failure mode of material elements and the inosculation of failed elements. | JU Yang1,2, YANG YongMing1, SONG ZhenDuo3 & XU WenJing4 1 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Beijing 100083, China 2 Department of Mechanical and Manufacturing Engineering, The University of Calgary, 2500 University Drive NW Calgary, AB T2N 1N4, Canada 3 China National Coal Mining Equipment Co. Ltd, Beijing 100011, China 4 Department of Materials and Metallurgy, The University of Utah, Salt Lake City, Utah 84112, USA | 2008 | Science China(Technological Sciences)2008，51，11： | 21 |
| 5 | Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone显示文摘Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and frac- tography, the fracture mechanism was studied and classified under meso and mi- cro scales, respectively. The differences between fractographs under different tem- peratures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under differ- ent temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of tem- perature and tensile stress may be another formation mechanism of micro fold in geology. | ZUO JianPing1,2, XIE HePing2,3, ZHOU HongWei1,2 PENG SuPing1 1 State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China 2 Institute of Rock Mechanics and Fractals, China University of Mining and Technology, Beijing 100083, China 3 Sichuan University, Chengdu 610065, China | 2007 | Science China(Technological Sciences)2007，50，6： | 11 |
| 6 | Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts显示文摘The dynamic mechanical properties of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102 s-1 were investigated by means of SHPB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric fractions.The properties of wave stress transmission,failure,strength,and energy consumption of RPC with varied fiber volumes and impact strain rates were analyzed.The influences of impact strain rates and fiber volumes on those properties were characterized as well.The general forms of the dynamic stress-strain relationships of RPC were modeled based on the experimental data.The investigations indicate that for the plain RPC the stress response is greater than the strain response,showing strong brittle performance.The RPC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as compared with the plain RPC.With a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced RPC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest increment.Elevating the fiber content makes trivial contribution to improving the residual deformability of RPC when the impact strain rate is constant.The tests also show that the fiber content affects the peak compressive strength and the peak deformability of RPC in a different manner.With a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber volume.The peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.The corresponding peak strain,however,incessantly rises with the increasing fiber volume.The total energy Edisp that RPC consumed during the period from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber fraction is not larger than 2%.It turns to decrease if the fiber volume exceeds 2%.The added fibers make various contributions to enhancing the capability of RPC to consume energy at different loading stages.If the fiber fraction is not larger than 2%,the added fibers make more contribution to enhancing the energy consumption ability of RPC in the period before the peak strain than in the period after the peak strain.The impact strain rate,however,distinctively affects the total energy that RPC consumed and the energy consumed in the different loading periods.The higher the impact strain rate,the more the energy consumed in the stages and therefore the higher the dynamic impact toughness.The empirical relationships of the peak compressive strength,corresponding peak strain,residual strain,total consumed energy and the energy consumed in the varied periods with the impact strain rate and the fiber fraction are derived.Four generalized forms of the dynamic impact stress-strain responses of RPC are formulated by normalizing stresses and strains as the generalized coordinates and by taking account of the influences of impact strain rates and fiber volumetric fractions. | JU Yang1,2,LIU HongBin1,SHENG GuoHua1,3 & WANG HuiJie1 1 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete,China University of Mining and Technology,Beijing 100083,China 2 Department of Mechanical and Manufacturing Engineering,University of Calgary,2500 University Drive,AB T2N 1N4,Canada 3 School of Resources and Civil Engineering,Northeastern University,Shenyang 110004,China | 2010 | Science China(Technological Sciences)2010，53，9： | 8 |
| 7 | Stratigraphic thermohistory and its implications for regional geoevolution in the Tarim Basin,NW China显示文摘Fourteen vitrinite reflectance profiles from the Tarim Basin,NW China,show that the vitrinite reflectance profiles of individual wells follow a faulted and dislocated dual-stage pattern in the eastern section of the Tazhong Uplift and in the Tabei Uplift.Vitrinite reflectance values in these profiles change sharply at the unconformity beneath the Lower Carboniferous Bachu or Upper Devonian Donghetang Formations,where the overlying Triassic to Carboniferous strata are still in a mature phase within the 'liquid oil window'.However,the underlying Lower Paleozoic reached the overmature phase beyond the 'liquid oil window' towards the end of the Silurian,or in the Early Devonian at the latest.Whereas the vitrinite reflectance profiles are attributed to a continuous,single-stage pattern in the western section of the Tazhong Uplift,in which the Lower Paleozoic is also in an overmature phase,their overmaturity would have been achieved relatively late in geological time.The stratigraphic thermohistory has the following implications to regional geoevolution:(1) The overmature Lower Ordovician to Cambrian strata in the eastern section of the Tazhong Uplift and in the Tabei Uplift,as well as in the Manjiaer Depression,could not have acted as the source kitchen for normal oil(so-called black oil);(2) The dissimilarity in vitrinite reflectance profiles between the eastern and western sections of the Tazhong Uplift reveals Early Paleozoic paleotectonic features,i.e.,lower at the east and higher at the west,whereas recent tectonic features formed since the Late Paleozoic are in reverse,i.e.,higher in the east and lower at the west;(3) Reconstruction of the denuded thickness of sediments overlying the Lower Ordovician strata suggests reconsideration on the paleotectonic features in the Tarim Basin;(4) Based on the sustained duration of the 'liquid oil window' for overmature source beds,it is predicted that the Suntuoguole Lower Uplift between the Awati and Manjiaer Depressions is a favorable potential source kitchen for Lower Paleozoic black oil. | WANG TieGuan1,DAI ShiFeng2,LI MeiJun1,ZHANG WeiBiao1,3,Qiu NanSheng1 & WANG GuangLi1 1 State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China 2 State Key Laboratory of Coal Resources & Safe Mining,China University of Mining & Technology,Beijing 100083,China 3 Exploration Research Center,Exploration & Development Institute,China Petrochemical Corporation,Beijing 100083,China | 2010 | Science China Earth Sciences2010，53，10： | 6 |
| 8 | Analysis on Land Development and Consolidation in Mountainous Area——Land Development and Consolidation Project in Haiba Village of Fengjie County显示文摘The paper describes the land use situation in the project area from two aspects. Firstly, natural situation (landscape, temperature, soil hydrology, natural disasters); secondly, land use situation (land use structure, project construction scale, land area of different vegetation classes). Through the research on the land development and consolidation of Haiba Village of Fengjie County, the project is concluded and the implementation cases of the project are reduced from the following six aspects: land leveling project, water conservancy and irrigation, farmland road engineering, project management system, project funds management and completion and delivery of construction project. Besides, the social, ecological and economic interests obtained by the projects are analyzed, so as to provide reference for promoting land development and consolidation in the future. | TIAN Mao-qiang1,2, ZHOU Chun-rong1,2, TAN Xian-long1,2, LI Yan-jun1,2 1. Chongqing Key Laboratory of Exogenic Minerallization and Mine Environment, Chongqing Institute of Geology and Mineral Resources, Chongqing 400042, China 2. Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining, Chongqing 400042, China | 2010 | Asian Agricultural Research2010，2，12： | 2 |
| 9 | Widespread use of gastric acid inhibitors in infants:Are they needed? Are they safe?显示文摘Gastroesophageal reflux is a common phenomenon in infants,but the differentiation between gastro-esophageal reflux and gastroesophageal reflux disease can be difficult.Symptoms are non-specific and there is increasing evidence that the majority of symptoms may not be acid-related.Despite this,gastric acid inhibitors such as proton pump inhibitors are widely and increasingly used,often without objective evidence or investigations to guide treatment.Several studies have shown that these medications are ineffective at treating symptoms associated with reflux in the absence of endoscopically proven oesophagitis.With a lack of evidence for efficacy,attention is now being turned to the potential risks of gastric acid suppression.Previously assumed safety of these medications is being challenged with evidence of potential side effects including GI and respiratory infections,bacterial overgrowth,adverse bone health,food allergy and drug interactions. | Mark Safe Wei H Chan Steven T Leach Lee Sutton Kei Lui Usha Krishnan | 2016 | World Journal of Gastrointestinal Pharmacology and Therapeutics2016，7，4： | 2 |
| 10 | Endocrine disruptors and falling sperm counts: lessons learned or not!显示文摘 | Stephen Safe | 2013 | Asian Journal of Andrology2013，15，2： | 2 |
| 11 | Endocrine disruptors and human health:is there a problem 显示文摘 | Safe S | 2004 | Toxicology2004，205，12： | 1 |
| 12 | Cancer chemotherapy with indole - 3 - carbinol, bis ( 3 ' - indolyl ) methane and synthetic analogs显示文摘 | Safe S Papineni S Chintharlapalli S | 2008 | Cancer Lett2008，269，2： | 1 |
| 13 | Sp transcription factor family and its role in cancer显示文摘 | Safe S Abdelrahim M | 2005 | Eur J Cancer2005，41，16： | 1 |
| 14 | Toxicological and pathophysio- logical roles of reactive oxygen and nitrogen species 显示文摘 | Roberts RA Smith RA Safe S | 2010 | Toxicology2010，276，2： | 1 |
| 15 | Sp transcription factor family and its role in cancer 显示文摘 | SAFE S ABDELRAHIM M | 2005 | Eur J Cancer2005，41，16： | 1 |
| 16 | Clinical correlates of environmental endocrine disruptors显示文摘 | Safe S | 2005 | Trends Endocrinol Metab2005，16，4： | 1 |
| 17 | Oxidative stress and ischemic myocardial syndromes 显示文摘 | Misra M K Safe at M Bhakuni P | 2009 | Med Sci Monit2009，15，10： | 1 |
| 18 | A receptor agonists as endocrine disruptors,antiestrogenic activity and mechanisms显示文摘 | Safe S Wang F | 1998 | Toxicol-Lecc1998，，： | 1 |
| 19 | 17 beta-estradiol and 4-hydroxytamoxifen-induced transactivation in breast,endometrial and liver cancer cells is dependent on ER-subtype,cell and promoter context显示文摘 | Castro-Rivera E Safe S | 2003 | Steroid Biochem Mol Biol2003，84，1： | 1 |
| 20 | Estrogen regulation of cyclin D1 gene expression in ZR-75 breast cancer cells involves multiple enhancer elements显示文摘 | Castro-Rivera E Samudio I Safe S | | 0，，33： | 1 |
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