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Fracture evolution and pressure relief gas drainage from distant protected coal seams under an extremely thick key stratum

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Journal of China University of Mining and Technology 2008年第2期18卷 182-186页

作者： WANG Liang CHENG yuan-ping LI feng-rong WANG Hai-feng LIU Hai-bo National Engineering Research Center for Coal ＆ Gas control China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China Haizi Coal Mine Huaibei Mining Industry Group Huaibei Anhui 235000 China

When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a ＂main key stratum＂, will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway （we can also drill them in the drilling field located high in an air gateway）. Given the practice in the Haizi mine, the gas drainage rate can reach 73% in the middie coal group, with a gas drainage radius over 100 m.

关键词： extremely thick key stratum protective seam exploitation fracture evolution gas drainage distant borehole drilling

Photocatalytic Characterization of TiO_2 Supported on Active Carbon

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Chinese Chemical Letters 2001年第6期12卷 549-550页

作者： Xue Ping LI feng YIN yuan LIN Jing bo ZHANG Xu Rui XIAO Laboratory of Photochemistry Center for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100080

The Photocatalytic characterization of TiO2 supported on active carbon was investigated for photocatalytic decomposition of dichloroacetic acid. It was found that TiO2 / AC exhibited a higher photocatalytic activity than pure TiO2. The reason is that active carbon acting as powerful adsorbent supports makes high concentration environments of organic pollutant molecules around TiO2 particles.

关键词： Photocatalysis TiO2 active carbon

Universal Concentration Scaling on Rheometric Properties of Polydisperse and High Molecular Weight Polyacrylamide Aqueous Solutions

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Chinese Journal of Polymer Science 2022年第11期40卷 1432-1440页

作者： yuan-Qi Fan Alfredo Lanzaro Xue-feng yuan Institute for Systems Rheology Guangzhou UniversityHigher Education Mega-CenterGuangzhou510006China

A great progress has been made over the last decades in studying concentration scaling on rheometric properties of monodisperse polymer ***,the effects of polydisperse polymer solutions on such a concentration scaling remain *** this work,rheometric properties of industrially relevant polydisperse and high molecular weight polyacrylamide(PAAm)aqueous solution have been *** results show a concentration scaling of the characteristic relaxation time,the plateau modulus and the zero-shear viscosity across a concentration range from 10c^(*)to 250c^(*).The time-concentration superposition principle is validated and extended in the data analysis of the terminal dynamic *** concentration scaling exponent of their shifting factors is significantly smaller than the results of monodisperse polymer solutions in good andθsolvents reported in the *** steady shear viscosity and shear stress of 18M PAAm aqueous solutions with relatively lower concentration(≤35c^(*))could also be superimposed into a master curve with the shear-thinning exponent of 0.73±0.03 and0.27±0.03,respectively,over a wide range of shear rates in about six orders of ***,for 18M PAAm aqueous solutions with higher concentration(≥48c^(*))in an intermediate shear thinning regime,the scaling exponent shows a pronounced concentration *** shear thinning exponent of steady shear viscosity varies from 0.73 to 0.57 as concentration is increased,and then increases from 0.57 to 0.90from sufficiently high shear *** increasing shear rate,the shear-thinning exponent of 18M PAAm aqueous solutions at all concentrations converges to the lower bounded value observed in the relatively less concentrated(≤35c^(*))18M PAAm aqueous solutions,i.e.,0.73±0.02 for shear viscosity and 0.27±0.02 for steady shear stress,*** reveals that the concentration effects of polydisperse polymer solutions could be greatly reduced by the dynamic"molecular indi

关键词： Polymer solution Polydispersity Rheometric properties Time-concentration superposition principle

Early Tracking Behavior in Small-field Quintessence Models

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Chinese Journal of Astronomy and Astrophysics 2003年第2期3卷 105-112页

作者： Wei Wang bo feng NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 InstituteofHighEnergyPhysics ChineseAcademyofSciencesBeijing100039

We study several quintessence models which are exotic at Q = 0, and use a simple constraint Q H/2π to check when they enter the tracking regime, disregarding the details of inflation. We find that it can also give strong constraints for V = VoQ-α, which has to enter the tracking regime after Inz - 10, while for the supergravity model V = V0Q-αexp(kQ2/2), the constraint is much weaker. For the exponential form of inverse power-law potential V = V0exp(λ/Q), it exhibits no constraints.

关键词： cosmology: theory

A thermodynamic study of the removal of HCI and H2S from syngas

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Frontiers of Chemical Science and Engineering 2012年第1期6卷 67-83页

作者： Joseph LEE bo feng School of Mechanical and lvlining Engineering the University of Queensland St Lucia Qld4072 Australia

Advanced integrated-gasification combined- cycle （IGCC） and integrated-gasification fuel cell （IFGC） systems require high-temperature sorbents that are capable of removing hydrogen chloride and hydrogen sulfide from coal derived gases to very low levels. HCI and H2S are highly reactive, corrosive, and toxic gases that must be removed to meet stringent environmental regulations, to protect power generation equipment and to control the emissions of contaminants. The thermodynamic behavior of 13 sorbents for the removal of HCI and H2S under various conditions including： initial toxic gas concentra- tion （1-10000 ppm）, operating pressure （0.1-11 Mpa）, temperature （300 K-1500 K）, and the presence of H2O were investigated. The correlation between HC1 and H2S was also examined. Thermodynamic calculations were carried out for the reactions of the 113 sorbents using a FaetSage 5.2 software package based on free energy minimization. The sorbents, Na2CO3, NaHCO3, K2CO3, and CaO are capable of completely removing chlorine at high temperatures （up to -1240 K） and at high pressures. Water vapor did not have any significant effects on the dechlorination capability of the sorbents. Nine of the sorbents namely; Cu20, Na2CO3, NaHCO3, K2CO3, CaO, ZnO, MnO, FeO, and Pbo, were determined to have great potential as desulfurization sorbents. Cu2Oand ZnO had the best performance in terms of the optimum operating temperature. The addition of water vapor to the reactant gas produces a slightly detrimental effi^ct on most of the sorbents, but FeO exhibited the worst performance with a reduction in the maximum operating temperature of about 428K. The dechlorination performance of the alkali sorbents was not affected by the presence of H2S in the reactions. However, the desulfurization capability of some sorbents was greatly affected by the presence of HC1. Particularly, the performance of Cu2O was significantly reduced when HC1 was present, but the performance ofFeO improved remarkably. gather

关键词： syngas cleaning sorbent desulfurization,dechlorination

Data-Domain Wave Equation Reflection Traveltime Tomography

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Journal of Earth Science 2015年第4期26卷 487-494页

作者： bo feng Huazhong Wang Wave Phenomena and Inversion Imaging Group School of Ocean and Earth ScienceTongji University

Estimation of an accurate macro velocity model plays an important role in seismic imag- ing and model parameter inversion. Full waveform inversion （FWI） is the classical data-domain inver- sion method. However, the misfit function of FWI is highly nonlinear, and the local optimization cannot prevent convergence of the misfit function toward local minima. To converge to the global minimum, FWI needs a good initial model or reliable low frequency component and long offset data. In this article, we present a wave-equation-based reflection traveltime tomography （WERTT） method, which can pro- vide a good background model （initial model） for FWI and （least-square） pre-stack depth migration （LS-PSDM）. First, the velocity model is decomposed into a low-wavenumber component （background velocity） and a high-wavenumber component （reflectivity）. Second, the primary reflection wave is pre- dicted by wave-equation demigration, and the reflection traveltime is calculated by an automatic picking method. Finally, the misfit function of the 12-norm of the reflection traveltime residuals is mini- mized by a gradient-based method. Numerical tests show that the proposed method can invert a good background model, which can be used as an initial model for LS-PSDM or FWI.

关键词： reflection traveltime tomography primary reflection wave wave equation demigration,background velocity building rough reflectivity.

Model-checking quantum systems

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National Science Review 2019年第1期6卷 28-31页

作者： Mingsheng Ying yuan feng Centre for Quantum Software and Information University of Technology Sydney State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Department of Computer Science and Technology Tsinghua University

INTRODUCTION We are currently in the midst of a second quantum revolution:transition from quantum theory to quantum engineering(e.g. quantum computing, communication, sensing). The main purpose of quantum theory is to find fundamental rules governing the existing physical *** contrast, quantum engineering aims at designing and implementing new systems (machines, devices, etc.) to achieve some desirable tasks, based on quantum theory.

关键词： Model-checking quantum systems

Generation of Febrile Seizures and Subsequent Epileptogenesis

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Neuroscience Bulletin 2016年第5期32卷 481-492页

作者： bo feng Zhong Chen Department of Pharmacology Key Laboratory of Medical Neurobiology of the Ministry of Health of China School of Medicine Zhejiang University

Febrile seizures（FSs） occur commonly in children aged from 6 months to 5 years. Complex（repetitive or prolonged） FSs, but not simple FSs, can lead to permanent brain modification. Human infants and immature rodents that have experienced complex FSs have a high risk of subsequent temporal lobe epilepsy. However, the causes of FSs and the mechanisms underlying the subsequent epileptogenesis remain unknown. Here, we mainly focus on two major questions concerning FSs： how fever triggers seizures, and how epileptogenesis occurs after FSs. The risk factors responsible for the occurrence of FSs and the epileptogenesis after prolonged FSs are thoroughly summarized and discussed. An understanding of these factors can provide potential therapeutic targets for the prevention of FSs and also yield biomarkers for identifying patients at risk of epileptogenesis following FSs.

关键词： Febrile seizures Epilepsy Epileptogenesis

Mineralization and osteoblast behavior of multilayered films on TiO_2 nanotube surfaces assembled by the layer-by-layer technique

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Chinese Chemical Letters 2016年第7期27卷 1091-1096页

作者： Yan Zhang Wen-Li Gao Zhi-yuan Liu Ya Jiang Ke Duan bo feng Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University School of Life Sciences and Engineering Southwest Jiaotong University

In this paper,the multilayer films of poly-L-lysine（PLL） and DNA were created on TiO2 nanotube surfaces using the layer-by-layer（LBL） self-assembly *** compositions of the assembled multilayered films were investigated by X-ray photoelectron *** properties of the multilayered films were evaluated by the biomimetic mineralization and osteoblast cell culture *** results indicated that PLL and DNA were successfully assembled onto TiO2 nanotube surfaces by electrostatic ***,the samples of assembled PLL or/and DNA had better bioactivity in inducing HA formation and promoting osteoblast cells adhesion,proliferation and early differentiation.

关键词： TiO2 nanotube Poly-L-lysine DNA Layer-by-layer Biological property