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Mechanical criterion for coal and gas outburst:a perspective from multiphysics coupling

International Journal of Coal Science & Technology 2021年第6期8卷 1423-1435页

作者： Ting Liu Baiquan Lin Xuehai Fu ang Liu School of Safety Engineering China University of Mining&TechnologyXuzhou 221116China Key Laboratory of CBM Resources and Dynamic Accumulation Process China University of Mining&TechnologyXuzhou 221008China Department of Energy and Mineral Engineering G3 Center and EMS Energy InstituteThe Pennsylvania State UniversityUniversity ParkPAUSA

Although a series of hypotheses have been proposed,the mechanism underlying coal and gas outburst remains *** the low-index outbursts encountered in mining practice,we attempt to explore this mechanism using a multiphysics coupling model considering the effects of coal strength and gas mass transfer on *** on force analysis of coal ahead of the heading face,a risk identification index C_(m)and a critical criterion(C_(m)≥1)of coal instability are *** to this criterion,the driving force of an outburst consists of stress and gas pressure gradients along the heading direction of the roadway,whereas resistance depends on the shear and tensile strengths of the *** results show that outburst risk decreases slightly,followed by a rapid increase,with increasing vertical stress,whereas it decreases with increasing coal strength and increases with gas pressure *** the response surface method,a coupled multi-factor model for the risk identification index is *** results indicate strong interactions among the controlling ***,the critical values of the factors corresponding to outburst change depending on the environment of the coal seams,rather than being *** the buried depth of a coal seam increases,the critical values of gas pressure and coal strength decrease slightly,followed by a rapid *** to its controlling factors,outburst can be divided into stress-dominated,coal-strength-dominated,gas-pressure-dominated,and multi-factor compound *** on this classification,a classified control method is proposed to enable more targeted outburst prevention.

关键词： Coal and gas outburst Critical criterion Multiphysics coupling Response surface method

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Numerical simulation of the three-dimensional flow-path in a ram-rotor

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航空动力学报 2010年第6期25卷 1358-1365页

作者： HAN Ji-ang zHONG Jing-jun YAN Hong-ming Marine Engineering College Dalian Maritime UniversityDalian 116026China School of Energy Science and Engineering Harbin institute of TechnologyHarbin 150001China

A kind of three-dimensional flow-path of the ram-rotor was designed in this paper according to the design method of the typical supersonic intake of aircraft and missiles,especially the design method of the compression ramp,the throat and the subsonic *** design Mach number of the flow-path was based on the averaged relative Mach number,regardless of the change of incoming Mach number along radial direction of the ***,the flowfield of the designed flow-path was simulated numerically with computational fluid dynamics software at design *** purpose of simulation was to obtain the details of the flowfield,including the structure of the shock wave system,position of flow separation zone,and so *** performance of the ram-rotor was also *** numerical results show the structure of the shock wave system in the flow-path is similar to that in the supersonic *** improve the overall performance of the ram-rotor,the reasonable compromise between the total pressure ratio and the isentropic adiabatic efficiency should be *** structure optimization of the flow-path and the configuration of the shock wave system have great influence on the performance of the ram-rotor.

关键词： ram-rotor flow-path supersonic intake numerical simulation design point

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Crystal Structure of a 4-Methyl-phenylacetylide-bridged Pt^(II)Cu^_(2)^(I) Heterotrinuclear Organometallic Complex

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Chinese Journal of Structural Chemistry 2004年第10期23卷 1103-1106页

作者： WU mei-mei CHEN zhong-Ning State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterThe Chinese Academy of SciencesFuzhouFujian 350002China Graduate School of the Chinese Academy of Sciences Beijing 100039China

The heterotrinuclear complex [PtCu2(m-dppm)2(dmbpy)2(m-h1,h2 C CPhCH3-4)2] (ClO4)21.5CH2Cl2 1 (dmbpy = 4,4-dimethyl-2,2?bipyridine, dppm = bis(diphenylphosphino)meth- ane) has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic system, space group P with a = 12.9359(3), b = 14.3908(2), c = 15.2121(3) ? α = 107.370(1), β = 93.539(1), γ = 108.207(1), V = 2529.59(8) ?, Mr = 2015.96, z = 1, Dc = 1.323 g/cm3, F(000) = 1019, m(MoKa) = 2.042 mm-1, the final R = 0.0604 and wR = 0.1529 for 8002 observed reflections with I > 2σ(I). The 4-methylphenylacetylides are bonded to the PtII and CuI centers in η1 (s) and η2 (p) coordination modes, respectively. The PtII atom is linked by one dppm bridge to adopt a square planar environment and CuI by one alkynyl ligand to assume a distorted tetrahedral geometry.

关键词： copper crystal structure 4,4'dimethyl-2,2'bipyridine 4-methyl-phenylacetylene platinum

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Chinese clinical practice guidelines for acute infectious diarrhea in children

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World Journal of Pediatrics 2018年第5期14卷 429-436页

作者： Jie Chen Chao-Min Wan Si-Tang G ong Feng F ang mei Sun Yuan Qian Ying Huang Bao-Xi Wang Chun-Di X u Li-Yan Ye mei Dong Yu Jin zhi-Hua Huang Qin-Bing Wu Chao-Min zhu You-Hong F ang Qi-Rong zhu Yong-Sui Dong Department of Gastroenterology Children’s HospitalZhejiang University School of MedicineHangzhou 310051China Department of Pediatrics West China Second HospitalSichuan UniversityChengdu 610041China Department of Gas troenterology Guangzhou Women and Children’s Medical CenterGuangzhou 510623China Department of Pediatrics Tongji Hospital Affiliated to Tongji Medical CollegeHuazhong University of Science and T echnologyWuhan 430030China Department of Gas troenterology Shengjing Hospital of China Medical UniversityShenyang 110004China Laboratory of Virology Beijing Key Laboratory of Etiology ofV iral Diseases inChildrenCapital Institute ofP ediatricsBeijing 100020China Department of Gas troenterology Children’s Hospital of Fudan UniversityShanghai 201102China Department of Inf ectious Diseases Children’s Hospital of Fudan UniversityShanghai 201102China Department ofP ediatrics Tangdu HospitalThe Fourth Military Medical UniversityXi’an 710038China Department of Pediatrics Ruijin HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 350025China Department of P ediatrics Fuzhou East HospitalFuzhou 350025China Department of P ediatrics Peking Union Medical College HospitalBeijing 100730China Department of Gas troenterology Children’s Hospital of N anjing Medical UniversityNanjing 210008China Department of Gas troenterology Children’s Hospital of Sooc how UniversitySuzhou 215003China Department of Inf ectious Diseases Children’s Hospital of Chongqing Medical UniversityChongqing 400014China

Background The guidelines addressed the evidence-based indications for the management of children with acute infectious diarrhea in Chinese pediatric population. Data sources The experts group of evidence development put forward clinical problems, collects evidence, forms prelimi-nary recommendations, and then uses open-ended discussions to form recommendations. The literature review was done for developing this guideline in databases including PubMed, Cochrane, EMBASE, China Biomedical Database, and Chinese Journal Full-text Database up to June 2013. Search the topic 'acute diarrhea' or 'enteritis' and 'adolescent' or 'child' or'Pediatric patient' or 'Baby' or 'Infant'. Results For the treatment of mild, moderate dehydration, hypotonic oral rehydration solutions (ORS) are strongly recom-mended. Intravenous (IV) rehydration is recommended for severe dehydration, with a mixture of alkali-containing dextrose sodium solution. Nasogastric feeding tube rehydration is used for children with severe dehydration without IV infusion conditions with ORS solution. Regular feeding should resume as soon as possible after oral rehydration or IV rehydration. The lactose-free diet can shorten the diarrhea duration. zinc supplements are recommended in children with acute infectious diarrhea. Saccharomyces boulardii and Lactobacillus Rhamnus are recommended to be used in acute watery diarrhea. Sac-charomyces boulardii is recommended in children with antibiotic-associated diarrhea as well. Montmorillonite and Racec-adotril (acetorphan) can improve the symptoms of diarrhea or shorten the course of acute watery diarrhea. Antibiotics are recommended with dysenteric-like diarrhea, suspected cholera with severe dehydration, immunodeficiency, and premature delivery children with chronic underlying disease;otherwise, antibiotics are not recommended. Conclusion The principles of the most controversial treatments with of acute infectious disease are reaching to a consensus in China.

关键词： Children Diarrhea Dehydration Infection Rehydration Treatment Probiotics

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An Information Entropy-Based Methodology to Construct the Avulsion Threshold in the Tail Reach of the Estuarine Alluvial Plain

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China Ocean Engineering 2023年第5期37卷 794-806页

作者： Yang zhuo-yuan XIA Jun-qiang DENG Shan-shan zHOU mei-rong JI zu-wen YU Xin State Key Laboratary of Water Resources and Management Wuhan UniversityWuhan 430072China Changjiang Survey PlanningDesign and Research Co.LtdWuhan 430010China State Key Laboratary of Simulation and Regulation of River Basin Water Cycle China Insititute of Water Resources and Hydropower ResearchBeijing 100048China Yellow River Institute of Hydraulic Research Yellow River Conservancy CommisionZhengzhou 450003China

Channel avulsion is a natural phenomenon that occurs abruptly on alluvial river deltas,which can affect the channel *** causes for avulsion could be generally categorized as topography-and flood-driven ***,previous studies on avulsion thresholds usually focused on topography-driven factors due to the centurial or millennial avulsion timescales of the world’s most deltas,but neglected the impacts of flood-driven *** the current study,a novel demarcation equation including the two driven factors was proposed,with the decadal timescale of avulsion being considered in the Yellow River Estuary(YRE).In order to quantify the contributions of different factors in each category,an entropy-based methodology was used to calculate the contributing weights of these *** factor with the highest weight in each category was then used to construct the demarcation equation,based on avulsion datasets associated with the *** avulsion threshold was deduced according to the demarcation *** avulsion threshold was then applied to conduct the risk assessment of avulsion in the *** results show that:two dominant factors cover respectively geomorphic coefficient representing the topography-driven factor and fluvial erosion intensity representing the flood-driven factor,which were thus employed to define a two dimensional mathematical space in which the demarcation equation can be obtained;the avulsion threshold derived from the equation was also applied in the risk assessment of avulsion;and the avulsion threshold proposed in this study is more accurate,as compared with the existing thresholds.

关键词： avulsion threshold threshold conditions entropy weight method tail reach Yellow River Estuary

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Fast frequency-domain equalization for single-carrier V-BLAST systems over multipath channel

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Science in China(Series F) 2009年第1期52卷 115-125页

作者： FENG ang YIN QinYe FAN JianCun School of Electronics and Information Engineering Xi'an Jiaotong University Xi'an 710049 China

A low complex minimum mean-square error frequency-domain decision feedback （MMSE-FDDF） equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems. Exploiting the factor that the discrete Fourier transform （DFT） is unitary, the proposed receiver can equalize the signals by the MMSE detecting to the spectrums in the frequency domain instead of the waveforms in the time domain. In order to obtain the right decisions, the detector must be able to equalize the overall spectrum with regard to each layer. This work can be performed very efficiently since the system matrix has been designed as a special block-circulant-block matrix. Similar to other V-BLAST-like systems, the detecting order has strong impact on the performance of MMSE-FDDF. Therefore, we further give a fast optimally sorting scheme for the MMSE-FDDF architecture. By using the newly constructed matrix, the coefficients computation and the sorting can be combined into one process, and then we employ the modified Gram-Schmidt （MGS） to simplify the process. The simulation results and the computational complexity analysis show that the proposed MMSE-FDDF has better tradeoff between the performance and the complexity than the existing algorithms. In addition, MMSE-FDDF can avoid the performance floor caused by the overlap-and-save technique in the severe dispersive channel.

关键词： single-carrier orthogonal frequency division multiplexing frequency domain equalization V-BLAST ordering Cholesky decomposition

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Graphical password： prevent shoulder-surfing attack using digraph substitution rules

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Frontiers of Computer Science 2017年第6期11卷 1098-1108页

作者： Lip Yee POR Chin Soon KU Amanul ISLAM Tan Fong ang Department of Computer Science and Information Technology University of Malaya Kuala Lumpur 50603 Malaysia Department of Computer Science Universiti Tunku Abdul Rahman (Jalan Universiti) Kampar 31900 Malaysia

In this paper, a new scheme that uses digraph substitution rules to conceal the mechanism or activity re- quired to derive password-images is proposed. In the pro- posed method, a user is only required to click on one of the pass-image instead of both pass-images shown in each chal- lenge set for three consecutive sets. While this activity is sim- ple enough to reduce login time, the images clicked appear to be random and can only be obtained with complete knowl- edge of the registered password along with the activity rules. Thus, it becomes impossible for shoulder-surfing attackers to obtain the information about which password images and pass-images are used by the user. Although the attackers may know about the digraph substitution rules used in the pro- posed method, the scenario information used in each chal- lenge set remains. User study results reveal an average login process of less than half a minute. In addition, the proposed method is resistant to shoulder-surfing attacks.

关键词： graphical password authentication shoulder-surfing data and computer security digraph substitution rules

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Visualizing Aβdeposits in live young AD model mice with a simple red/near-infrared-fluorescent AIEgen

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Science China Chemistry 2022年第2期65卷 339-352页

作者： Yipu Wang Dong mei Xinyi z.ang Da-Hui Qu Ju mei Key Laboratory for Advanced Materials Feringa Nobel Prize Scientist Joint Research CenterFrontiers Science Center for Materiobiology and Dynamic ChemistryJoint International Research Laboratory for Precision Chemistry and Molecular EngineeringInstitute of Fine ChemicalsSchool of Chemistry&Molecular EngineeringEast China University of Science&TechnologyShanghai 200237China Clinical Research Center Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijing 100045China

Precise and early detection ofβ-amyloid(Aβ)deposits in situ and in real time is pivotal to the diagnosis and early intervention of Alzheimer’s disease(AD).Optical imaging stands out to be a promising technique for such a task;however,it still remains a big challenge,due to the lack of high-performance imaging contrast *** by poor blood-brain barrier(BBB)penetrability,short-wavelength excitation and emission,as well as the aggregation-caused quenching effect,the widely used goldstandard probes cannot be used for early in-vivo imaging of Aβ***,we integrate the Aβdeposits-favored geometry,amphiphilic and zwitterionic molecular structure,extended D-π-A electronic structure,and 3 D conformation into one molecule,facilely establishing a simple and economic imaging contrast agent that enjoys high specificity and affinity to Aβdeposits,good BBB penetrability,bright red/near-infrared fluorescence,low interference from autofluorescence,aggregation-induced emission(AIE)feature,high signal-to-noise ratio(SNR),and high ***-vitro,ex-vivo,and in-vivo experiments with different strains of mice indicate that AIE-CNPy-AD holds the universality to Aβdeposits ***,AIE-CNPy-AD is even able to precisely trace the small and sparsely-distributed Aβdeposits in AD model mice as young as 4-month-old APP/PS1 mice,the youngest having Aβ***,the present probe could clearly reveal the increase and enlargement of Aβdeposits as the mice ***,AIE-CNPy-AD might be an ideal alternative for early AD diagnosis and highly reliable monitoring of AD progression.

关键词： Aβdeposits AIE Alzheimer’s disease(AD) red/NIR fluorescence in-vivo imaging diagnosis

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Solid-state alloying of Al-Mg alloys by accumulative roll-bonding:Microstructure and properties

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Journal of Materials Science & Technology 2022年第30期125卷 238-251页

作者： X.M.mei Q.S.mei J.Y.Li C.L.Li L.Wan F.Chen z.H.Chen T.Xu Y.C.Wang Y.Y.Tan School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Key Laboratory of Hydraulic Machinery Transients(Wuhan University) Ministry of EducationWuhan 430072China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan 430023China

In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh *** results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 *** as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation *** Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of ***,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by *** study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.

关键词： Solid-state alloying Al-Mg alloys Mechanical properties IGC resistance ARB

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Location Service Information Supporting System Based on Ontology

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Journal of Integrative Agriculture 2012年第5期11卷 858-864页

作者： HUang Dong-mei Fang Qian YU Qing-mei College of Information Shanghai Ocean UniversityShanghai 201306P.R.China

In order to solve the problem of how to collect and manage large amount of location information and improve the accuracy of location service, interactive information supporting system based on ontology and location service is presented in this paper. It can transmit special information about users＇ location to front-end instantaneously, so it is very convenient for their daily life. It makes full use of the available wireless communication, which is easy to arrange and convenient for users.

关键词： ontology location service location information supporting system

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