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Improved mesh-free SPH approach for loose top coal caving modeling

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Particuology 2024年第12期95卷 1-27页

作者： Xiangwei Dong qiang zhang Yang Liu Xin Liu College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao266590China Shaanxi Coal Group Shenmu Hongliulin Mining Co. LtdYulin719314China

This study presents an innovative model in computational geotechnical engineering by improving the Smoothed Particle Hydrodynamics(SPH)method for simulating loose particle dynamics in coal caving *** improved model integrates an elastic-perfectly plastic constitutive model with the Drucker-Prager yield criterion and includes several improvements aimed at boosting accuracy,stability,and *** improvements include gravity loading coupled with particle damping,first-order stress field smoothing,and kernel gradient correction.A series of numerical experiments validates the effectiveness of the improved SPH model,demonstrating its capability to predict large deformations and track the evolution of the coal-rock interface in coal caving ***,the study analyzes the model's sensitivity to material parameters such as the angle of friction and material density,which aids in configuring the model for distinct coal mining *** show that the non-cohesive elastic-perfectly plastic constitutive model can effectively simulate the flow behavior of granular particles,and the landslide simulation results are in good agreement with the *** improved SPH algorithm with stress smoothing technique solves the problem of numerical noise,and the“double peak”stress distribution around the coal outlet is *** established SPH model offers an effective tool for understanding dynamics behaviors of loose top ***,the model requires only five material parameters,which can be identified through standard experiments,avoiding the typically arduous process of parameter selection or calibration commonly existing in Discrete Element Method simulations.

关键词： Smoothed particle hydrodynamics(SPH) Top coal caving Loose coal and rock particles Elastic-perfectly plastic constitutive model Model sensitivity analysis

Deformation and Failure Analysis of River Levee Induced by Coal Mining and Its Influence Factor

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Computer Modeling in Engineering & Sciences 2017年第2期113卷 183-194页

作者： Meng Li Jixiong zhang Nan Zhou qiang zhang State Key Laboratory of Coal Resources and Safe Mining School of MinesChina University of Mining&TechnologyXuzhou221116China

To study the influence of coal mining on the stability of river levees,a mechanical model of mining-induced river levee deformation was *** was based on the mining-induced deformation characteristics of river levees and the application of a typical surface subsidence ***,a failure criterion was proposed for river *** some examples,the deformation of,and stress distribution through,river levees under the influence of mining were obtained:the maximum tensile stress on the bottom of the river levee was less than the tensile strength,under which circumstance the river levee remained ***,this research analyzed the influence of three factors including the maximum surface subsidence wmax,half-length of surface subsidence basin L,and foundation coefficient k on the stability of river *** showed that reducing the mining height of the working face and the foundation co-efficient,and increasing the strike length of the working face could reduce the influence of mining on river *** results provided a theoretical basis for predicting the mining-induced deformation and failure of river levees.

关键词： Mining river levee surface subsidence mechanical model Winkler foundation beam

Optimized human factor IX expression cassettes for hepaticdirected gene therapy of hemophilia B

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Frontiers of Medicine 2015年第1期9卷 90-99页

作者： Ru zhang qiang Wang Lin zhang Saijuan Chen State Key Laboratory for Medical Genomics Shanghai Institute of Hematology Ruifin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200025 China

Gene therapy provides a potential cure for hemophilia B, and significant progress has been achieved in liver-directed gene transfer mediated by adeno-associated viral vectors. Recent clinical trials involving the use of a self-complementary adeno-associated virus serotype 8-human codon-optimized factor IX （AAV8-hFIXco） vector demonstrated encouraging efficacy with hFIX expression stabilized at 1% to 6% of normal level in patients, but safety concerns related to high vector doses are still present. Thus, further improvement of AAV vectors and hFIX expression cassette may positively contribute to the ultimate success of hemophilia B gene therapy. In this study, to obtain a higher expression level of hFIX that potentiates the coagulant capacity of recipients, human FIX expression vector was optimized by upgrading the codon adaption index and adjusting the GC content, inserting a Kozak sequence （GCCACC）, and introducing a gain-of-function mutation, R338L （FIX Padua）. The efficiency of the published and the presently constructed cassettes was compared through in vivo screening. In addition, the regulatory elements that control the FIX gene expression in these cassettes were screened for liver-specific effectiveness. Among all the constructed cassettes, scAAV-Pre-hFIXco-SIH-R338L, which was the construct under the control of the prothrombin enhancer and prealbumin promoter, resulted in the highest level of coagulant activity, and the expression levels of two constructed cassettes （scAAV-Chi-hFIXco-SIH-R338L and scAAV-Pre- hFIXco-SIH-R338L） were also higher than that of the published cassette （scAAV-LPI-hFIXco-SJ）. In summary, our strategies led to a substantial increase in hFIX expression at the protein level or a remarkably elevated coagulant activity. Thus, these reconstructs of hFIX with AAV vector may potentially contribute to the creation of an efficacious gene therapy of hemophilia B.

关键词： factor IX hemophilia B liver-specific regulatory elements hydrodynamic gene transfer

A top-down positioning scheme for underwater wireless sensor networks

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Science China(Information Sciences) 2014年第3期57卷 288-297页

作者： zhang SenLin zhang qiang LIU MeiQin FAN Zhen College of Electrical Engineering Zhejiang University

In order to increase the localization coverage while keeping the localization error small in a unique network architecture in which there are not evenly distributed anchor nodes with great ability of communication or additional infrastructure,a Top-down Positioning Scheme(TPS)for underwater acoustic sensor networks is *** defining node’s confidence reasonably,TPS insures the quality of the new reference *** also refines the nodes which have just been positioned via the gradient method and helps non-localized nodes search for more reference nodes via the new scheme for 3D Euclidean distance *** comparing the new scheme for 3D Euclidean distance estimation with the existing scheme,the new scheme is shown to have greater ability to estimate two-hop Euclidean distance in 3D *** results show that TPS which integrates node’s confidence defined reasonably,the gradient method,and the new scheme for 3D Euclidean distance estimation can increase the localization coverage ratio,while keeping the localization error small.

关键词： underwater wireless sensor networks top-down positioning scheme node’s confidence gradient method 3D Euclidean distance estimation

Pterisemipol,a novel sesquiterpenoid from Pteris semipinnata L.

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Chinese Chemical Letters 2007年第11期18卷 1386-1388页

作者： qiang zhang Li Jiang Xuan State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 201203 China

A novel sesquiterpenoid, pterisemipol, was isolated from Pteris semipinnata L. Its skeleton, namely pterisane, was considered to be rearranged from protoilludane and its structure was elucidated on the basis of spectr... 详细信息

关键词： Pwris semipinnata L. Ptedsemipol Ptedsane Sesquiterpenoid

Development of a wide-range and fast-response digitizing pulse signal acquisition and processing system for neutron flux monitoring on EAST

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Nuclear Science and Techniques 2022年第3期33卷 126-136页

作者： Li Yang Hong-Rui Cao Jin-Long Zhao Zi-Han zhang qiang Li Guo-Bin Wu Yong-qiang zhang Guo-qiang Zhong Li-Qun Hu Zi-Jun zhang Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Hefei University of Technology Hefei 230009China

The neutron count rate fluctuation reaches six orders of magnitude between the ohmic plasma scenario and high power of auxiliary heating on an experimental advanced superconducting tokamak(EAST).The measurement result of neutron flux monitoring(NFM)is a significant feedback parameter related to the acquisition of radiation protection-related information and rapid fluctuations in neutron emission induced by plasma magnetohydrodynamic ***,a wide range and high time resolution are required for the NFM system on *** satisfy these requirements,a digital pulse signal acquisition and processing system with a wide dynamic range and fast response time was *** present study was conducted using a field-programmable gate array(FPGA)and peripheral component interconnect extension for instrument express(PXIe)*** digital dual measurement modes,which are composed of the pulse-counting mode and AC coupled square integral's Campbelling mode,were designed to expand the measurement range of the signal acquisition and processing *** time resolution of the signal acquisition and processing system was improved from 10 to 1 ms owing to utilizing highspeed analog-to-digital converters(ADCs),a high-speed PXIe communication with a direct memory access(DMA)mode,and online data preprocessing technology of *** signal acquisition and processing system was tested experimentally in the EAST radiation *** test results showed that the time resolution of NFM was improved to 1 ms,and the dynamic range of the neutron counts rate was expanded to more than 10^(6) counts per *** Campbelling mode was calibrated using a multipoint average linear fitting method;subsequently,the fitting coefficient reached ***,the newly developed pulse signal acquisition and processing system ensures that the NFM system meets the requirements of high-parameter experiments conducted on EAST more effectively.

关键词： EAST Neutron flux monitoring High time resolution Wide range Pulse signal acquisition and processing system

Protective Effects of Phellodendron Species on Bone Health: A Novel Perspective on Their Potentials in Treating Osteoporosis and Osteoarthritis

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Chinese Journal of Integrative Medicine 2024年第4期30卷 379-384页

作者： XIN Li TAN Guo-yao zhang qiang zhang Qun Good Clinical Practice Development Guangdong Provincial Key Laboratory of Bone and Joint Degeneration DiseasesThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou(510630)China Department of Pharmacy Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou(510120)China

Phellodendron(PN)species,traditionally used in Chinese medicine for centuries,hold promise as a potential treatment for osteoporosis(OP)and osteoarthritis(OA)due to their bioactive *** bioactive compounds,including berberine and palmatine,exhibit anti-inflammatory,antioxidant,and bone-protective properties,contributing to their potential therapeutic benefits in promoting bone health and preventing bone ***,challenges such as the need for standardized preparation and dosing,limited clinical studies,and potential interactions with other medications hinder their clinical ***,the rich history of PN species in Chinese medicine provides a promising foundation for future investigation into their potential as alternative treatments for OP and *** research is needed to fully understand the underlying mechanisms of action and explore the clinical implications of PN for bone health.

关键词： Phellodendron species bone health osteoporosis osteoarthritis review

Burst detection in turbulent channel flows based on large eddy simulation databases

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Science China(Physics,Mechanics & Astronomy) 2005年第4期48卷 469-484页

作者： zhang qiang ZHOU Jifu LI Jiachun Institute of Mechanics Chinese Academy of Sciences Beijing 100080 Institute of Mechanics Chinese Academy of Sciences Beijing 100080 Institute of Mechanics Chinese Academy of Sciences Beijing 100080

Reliable turbulent channel flow databases at several Reynolds numbers have been established by large eddy simulation (LES), with two of them validated by comparing with typical direct numerical simulation (DNS) results. Furthermore, the statistics, such as velocity profile, turbulent intensities and shear stress, were obtained as well as the temporal and spatial structure of turbulent bursts. Based on the LES databases available, the conditional sampling methods are used to detect the structures of burst events. A method to deterimine the grouping parameter from the probability distribution function (pdf) curve of the time separation between ejection events is proposed to avoid the errors in detected results. And thus, the dependence of average burst period on thresholds is considerably weakened. Meanwhile, the average burst-to- bed area ratios are detected. It is found that the Reynolds number exhibits little effect on the burst period and burst-to-bed area ratio.

关键词： turbulence, burst period, burst-to-bed area ratio, LES.

Simulation of free-surface flow using a boundless grid

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Science China(Information Sciences) 2013年第3期56卷 38-47页

作者： WANG ChangBo zhang qiang KONG FanLong Software Engineering Institute East China Normal University Shanghai Key Laboratory of Trustworthy Computing East China Normal University

Physically based fluid simulation in recent years has been successful for small-scale fluids such as liquid in a cubic ***,for boundless free-surface flow of large scale and irregular area,there is a critical trade-off between simulation efficiency and accuracy because of the restriction of the traditional regular computational *** paper introduces boundless computational grids based on hierarchical runlength encoding to simulate large-scale free-surface *** first modeled the free-surface flow with a lattice Boltzmann method,and calculated the surface curvature in the update *** then introduced an effective method with which to calculate the surface curvature according to the surface tension so that the surface detail was enhanced,and obtained the curvature of each surface effectively as it was ***,we dynamically compressed and indexed the computational cells with the improved hierarchical run-length encoding algorithm,so that the grid expands dynamically according to the fluid flow and the computational resources used were proportional to the volume of the *** fluids in different situations were simulated *** proposed method makes the best of the computational resources to perform the simulation with high resolution,and dynamically allocates resources so that the fluid can expand in random directions without boundaries,which is suited to the simulation of large-scale visual scenes.

关键词： fluid simulation free surface boundless grid hierarchical run-length encoding computing resource