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| 1 | 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 |
| 2 | An experimental investigation on the mechanism of fluid flow through single rough fracture of rock显示文摘The structure of fractures in nature rock appears irregular and induces complicated seepage flow behavior.The mechanism and quantitative description of fluid flow through rock fractures is a difficult subject that has been greatly concerned in the fields of geotechnical,mining,geological,and petroleum engineering.In order to probe the mechanism of fluid flow and the effects of rough structures,we conducted a few laboratory tests of fluid flow through single rough fractures,in which the Weierstrass-Mandelbrot fractal function and PMMA material were employed to produce the fracture models with various fractal roughnesses.A high-speed video camera was employed to record the fluid flow through the entire single rough fracture with a constant hydraulic pressure.The properties of fluid flow varying with the fracture roughness and the influences of the rough structure were analyzed.The components of flow resistance of a single rough fracture were discussed.A fractal model was proposed to relate the fluid resistance to the fracture roughness.A fractal equivalent permeability coefficient of a single rough fracture was formulated.This study aims to provide an experimental basis and reference for better understanding and quantitatively relating the fluid flow properties to the structures of rock fractures. | JU Yang ZHANG QinGang YANG YongMing XIE HePing GAO Feng WANG HuiJie | 2013 | Science China(Technological Sciences)2013，56，8： | 28 |
| 3 | Computation of fractal dimension of rock pores based on gray CT images显示文摘The characterization of pore structure in rocks is relevant in determining their various mechanical behaviors. Digital image processing methods integrated with fractal theory were applied to analyze images of rock slices obtained from industry CT, elucidating the characteristics of rock pore structure and the relationship between porosity and fractal dimensions. The gray values of pixels in CT images of rocks provide comprehensive results with respect to the attenuation coefficients of various materials in corresponding rock elements, and these values also reflect the effect of rock porosity at various scales. A segmentation threshold can be determined by inverse analysis based on the pore ratios that are measured experimentally, and subsequently binary images of rock pores can be obtained to study their topological structures. The fractal dimension of rock pore structure increases with an increase in rock pore ratio, and fractal dimensions might differ even if pore ratios are the same. The more complex the structure of a rock, the larger the fractal dimension becomes. The experimental studies have validated that fractal dimension calculated directly from gray CT images of rocks can give an effective complementary parameter to use alongside pore ratios and they can suitably represent the fractal characteristics of rock pores. | PENG RuiDong YANG YanCong JU Yang MAO LingTao YANG YongMing | 2011 | Chinese Science Bulletin2011，56，31： | 25 |
| 4 | Microwave photocatalytic degradation of Rhodamine B using TiO_2 supported on activated carbon:Mechanism implication显示文摘The photocatalytic degradation of Rhodamine B(RhB) was carried out using TiO2 supported on activated carbon(TiO2-AC) under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM) and Brunauer-Emmett-Teller(BET).In the process of microwave-enhanced photocatalysis(MPC),RhB(30 mg/L) was almost completely decoloured in 10 min,and the mineralization effciency was 96.0% in 20 min.The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25.Additionally,according to gas chromatography/mass spectrometry(GC/MS) and liquid chromatography/mass spectrometry(LC/MS) identification,the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates(N,N-diethyl-N'-ethyl-rhodamine(DER)),oxalic acid,malonic acid,succinic acid,and phthalic acid,maleic acid,3-nitrobenzoic acid,and so on.The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure,and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide. | HE Zhong,YANG Shaogui,JU Yongming,SUN Cheng State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210093,China. | 2009 | Journal of Environmental Sciences2009，21，2： | 22 |
| 5 | Laboratory investigation on mechanisms of stress wave propagations in porous media显示文摘A number of porous models having the similar statistical characteristics of pores and physical properties with natural sandstones have been produced using reactive powder concrete(RPC) and polystyrenes.Spit-Hopkinson-Pressure-Bar tests and CT scans have been carried out on the models with the various porosities to probe the performance of wave propagations and the responses of pores and the matrix during wave propagations.It is shown that porosities significantly influence wave propagations.For an identical impact strain rate,the greater the porosity is,the larger the amplitude of the reflected wave appears,the more the peak in the reflected wave presents,and the smaller the amplitude of the trans-mitted wave turns out.A single peak emerges in the reflected wave when the porosity falls down to 5%.The larger the impact strain rate,the much remarkable the phenomena.The energy-dissipated ratio of porous models,i.e.,WJ /WI,linearly increases with the increment of porosities.The ratio is sensitive to the impact strain rate.Differences in the performance of wave propagations and energy dissipation result from the varied mechanisms that pores response to impacts.For the porosity less than 10%,the mechanism appears to be a process fracturing the matrix to generate new surfaces or pores.Energy has primarily been dissipated in creating new surfaces or pores.No apparent pore deformation takes place.The impact strain rate takes little effect on pore geometry.For the porosity of 15% or more,the mechanism works depending on the impact strain rate.When a low impact strain rate applies,the mechanism still appears to crack the matrix to generate surfaces or pores,but the amount is lower as compared to the case with a low porosity.If a large impact stain rate applies,the mechanism combines both fracturing the matrix and deforming the pores,with the deforming pores predominating.The vast majority of energy has been dissipated to deform pores.Only high porosity and impact strain rate can bring significant deformation to the pores.The proposed eccentricity of pores is capable of character-izing the geometry of pores and its change during wave propagations. | JU Yang YANG YongMing MAO YanZhe LIU HongBin WANG HuiJie | 2009 | Science China(Technological Sciences)2009，52，5： | 13 |
| 6 | Room temperature phosphorescence from natural products: Crystallization matters显示文摘Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens. | GONG YongYang TAN YeQiang MEI Ju ZHANG YiRen YUAN WangZhang ZHANG YongMing SUN JingZhi TANG Ben Zhong | 2013 | Science China Chemistry2013，56，9： | 8 |
| 7 | Microwave-en-hanced H2O2-based process for treating aqueous malachite green solutions:Intermediates and degradation mechanism显示文摘 | Ju Yongming Yang Shaogui Ding Youchao | 2009 | Journal of Hazardous Materials2009，171，123： | 1 |
| 8 | Synthesis of surface sulfated BiWO with enhanced photocatalytic performance显示文摘Sulfated BiWO(SBiWO)was synthesized by an impregnation method to enhance the visible-light-driven photoactivities of BiWO(BiWO).The characterization results verified that sulfate anion mainly anchored on the catalyst surface greatly extended the visiblelight-responsive range without destroying the crystal lattice.Moreover,the SBiWO-based photoactivities were evaluated with the removal of Malachite Green(MG)under UV-Vis irradiation emitted from two microwave-powered electrodeless discharge lamps(MPEDL-2)and under visible light(λ>420nm).The results demonstrated that the kinetic constant was increased 2.25 times,varying from 0.1478(BiWO)to 0.3328min-1(SBiWO-1).Similar results were also obtained for the visible light-driven reaction.Furthermore,radical scavengers such as t-butanol restricted the visible-light induced degradation of MG over BiWO and SBiWO-1.This indicated that the sulfating process increased the generation of reactive oxygen species,which was further verified by molecular probe with salicylic acid.Thus,more blue-shifting at λ=618nm was observed over SBiWO.On the basis of the above results,the photocatalytic mechanism over the sulfated catalyst was also discussed. | Yongming Ju Jianming Hong Xiuyu Zhang Zhencheng Xu Dongyang Wei Yanhong Sang Xiaohang Fang Jiande Fang Zhenxing Wang | 2012 | Journal of Environmental Sciences2012，24，12： | 1 |
| 9 | Room temperature phosphorescence from natural products: Crystallization matters显示文摘Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch,cellulose,bovine serum albumin(BSA),and some other carbohydrates.Whereas being practically nonluminescent in solutions and TLC plates,they emit bright phosphorescence in the crystalline states with lifetime up to microseconds,exhibiting crystallization-induced phosphorescence(CIP)characteristics.The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens. | GONG YongYang TAN YeQiang MEI Ju ZHANG YiRen YUAN WangZhang ZHANG YongMing SUN JingZhi TANG BenZhong | 2013 | 中国科学:化学2013，43，9： | 0 |
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