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Deformation characteristics and damage ontologies of soft and hard composite rock masses under impact loading

Journal of Mountain Science 2024年第5期21卷 1715-1727页

作者： LI Jinhua ZHANG Tianyu WU Baolin su peili YANG Yang WANG Pan Architectural and Civil Engineering College Xi’an University of Science and TechnologyXi’an 710054China

As one of the most common occurring geological landforms in deep rock formations, the dynamic mechanical properties of layered composite rock bodies under impact loading have been widely studied by scholars. To study the dynamic properties of soft and hard composite rocks with different thickness ratios, this paper utilizes cement, quartz sand and gypsum powder to construct soft and hard composite rock specimens and utilizes a combination of indoor tests, numerical calculations, and theoretical analyses to investigate the mechanical properties of soft and hard composite rock bodies. The test results reveal that:(1) When the proportion of hard rock increases from 20% to 50%, the strength of the combined rock body increases by 69.14 MPa and 87 MPa when the hard rock face and soft rock face are loaded, respectively;however, when the proportion of hard rock is the same, the compressive strength of the hard rock face impact is 9%-17% greater than that of the soft rock face impact;(2) When a specimen of soft and hard combined rock body is subjected to impact loading, the damage mode involves mixed tension and shear damage, and the cracks generally first appear at the ends of the specimen, then develop on the laminar surface from the impact surface, and finally end in the overall damage of the soft rock part. The development rate and the total number of cracks in the same specimen when the hard rock face is impacted are significantly greater than those when the soft rock face is impacted;(3) By introducing Weibull’s statistical strength theory to establish the damage variables of soft-hard combined rock bodies, combined with the DP strength criterion, the damage model and the Kelvin body are concatenated to obtain a statistical damage constitutive model, which can better fit the full stress-strain curve of soft-hard combined rock body specimens under a single impact load.

关键词： Soft and hard composite rock mass Dynamic properties Split Hopkinson pressure bar(SHPB) Numerical simulation Intrinsic damage model

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井下动水截流施工骨料堆积生长机制研究

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煤炭科学技术 2024年第5期52卷 209-221页

作者：苏培莉杨述刘锋西安科技大学建筑与土木工程学院陕西西安710054

灌注骨料形成阻水屏障实现截流降速是井下治水工程的关键所在。为定量描述骨料堆积生长的时空演化机理,提出了将骨料沉降堆积过程切分为具有一定厚度的片状颗粒层堆叠过程的分析计算方法,以及动水环境中骨料灌注后从沉降到堆积全过程关... 详细信息

灌注骨料形成阻水屏障实现截流降速是井下治水工程的关键所在。为定量描述骨料堆积生长的时空演化机理,提出了将骨料沉降堆积过程切分为具有一定厚度的片状颗粒层堆叠过程的分析计算方法,以及动水环境中骨料灌注后从沉降到堆积全过程关键参量(颗粒水平移距xd,动水休止角ψ,未接顶区流速U,骨料留存临界流速U_(cr))的理论计算公式,在此基础上构建了骨料堆积体生长预测模型。通过CFD-DEM双向耦合算法研究了骨料灌注期间流场分布演化特征和骨料堆积形态差异,并验证了预测模型合理性。研究表明:空间上,依据初始流速U_(s)是否超过骨料起动流速U_(c)或骨料留存临界流速U_(cr),可将截流初期骨料沉积主域的所在位置划分为3个区域,若沉积主域位于③区,则将其视为无效灌注;时间上,骨料堆积体生长过程可归结为3个阶段:高度快速增长阶段、高度长度同步生长阶段、仅水平向伸长阶段;初始流速决定了第1阶段的有无,而灌注条件(骨料粒径、灌注速度)主导着第1阶段所持续的时间;基于泥沙运动力学中推移质输沙率、起动流速等概念,得出了堵孔现象发生及骨料能否留存的临界判据;数值模拟试验结果表明,预测模型能够较好地刻画骨料灌注后的堆积生长规律,骨料堆积稳定后,理论计算值与模拟试验值相对误差小于10%。

关键词：煤矿突水骨料灌注临界流速沉积主域固–液两相流

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煤岩体突水通道中骨料沉积运移规律研究

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煤炭科学技术 2023年第8期51卷 200-207页

作者：苏培莉文嘉豪谷拴成刘锋李冲西安科技大学建筑与土木工程学院陕西西安710054

先行灌注骨料后注浆可有效控制煤岩体突水。骨料在煤岩体突水通道中沉积运移规律的研究是确定骨料粒径、骨料灌注量以及骨料灌注孔间距的重要前提,但目前在该方面的理论和试验研究甚少,实际施工主要依赖经验,带有较大的盲目性。鉴于此,... 详细信息

先行灌注骨料后注浆可有效控制煤岩体突水。骨料在煤岩体突水通道中沉积运移规律的研究是确定骨料粒径、骨料灌注量以及骨料灌注孔间距的重要前提,但目前在该方面的理论和试验研究甚少,实际施工主要依赖经验,带有较大的盲目性。鉴于此,基于浆体管道输送理论和泥沙运动力学,结合牛顿第二定律,将骨料从灌注孔进入突水通道的全运移过程划分为:自由落体,类平抛以及滑移3个运动阶段,并分别对其进行受力分析,建立由单颗骨料到骨料颗粒群的沉积运移扩散模型,得出表征骨料颗粒群在水平方向上的沉积运移规律;自行设计煤岩体突水通道骨料沉积运移可视化的模型试验平台,借助该平台开展在不同动水流速、骨料粒径、灌注高度等多因素影响下的骨料沉积运移模型试验,分析骨料在突水通道内的沉积运移规律,得到在不同试验方案下骨料沉积运移区的总长度。试验结果表明:骨料实际运移过程与理论3个运动阶段的假设吻合,骨料沉积运移距离的试验值与理论计算值平均误差为7.34%;在控制投注高度与动水条件一致的前提下,相较细骨料(粒径≤5 mm)而言,理论公式对于粗骨料(粒径>5 mm)更具适用性;在工程中解决煤岩体突水问题时,若骨料粒径>5 mm,利用本文理论公式可计算得到骨料颗粒群在水平方向上的运移距离,从而确定骨料灌注孔的间距,降低实际施工过程中的盲目性。

关键词：突水骨料颗粒沉积运移自由落体类平抛滑移突水通道注浆加固

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Shock Formation for 2D Isentropic Euler Equations with Self-similar Variables

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 349-412页

作者： Wenze su School of Mathematical Sciences Fudan UniversityShanghai 200433China

The author studies the 2D isentropic Euler equations with the ideal gas *** exhibits a set of smooth initial data that give rise to shock formation at a single point near the planar *** solutions to the 2D isentropic Euler equations are associated with non-zero vorticity at the shock and have uniform-in-time-1/3-Holder ***,these point shocks are of self-similar type and share the same profile,which is a solution to the 2D self-similar Burgers *** proof of the solutions,following the 3D construction of Buckmaster,Shkoller and Vicol(in 2023),is based on the stable 2D self-similar Burgers profile and the modulation method.

关键词： 2D isentropic Euler equations Shock formation Self-similar solution

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Design and pricing of maintenance service contract based on Nash non-cooperative game approach

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Journal of Systems Engineering and Electronics 2024年第1期35卷 118-129页

作者： su Chun HUANG Kui School of Mechanical Engineering Southeast UniversityNanjing 211189China

Nowadays manufacturers are facing fierce *** from the products,providing customers with multiple maintenance options in the service contract becomes more popular,since it can help to improve customer satisfaction,and ultimately promote sales and maximize profit for the *** considering the combinations of corrective maintenance and preventive maintenance,totally three types of maintenance service contracts are ***,attractive incentive and penalty mechanisms are adopted in the *** this basis,Nash non-cooperative game is applied to analyze the revenue for both the manufacturer and customers,and so as to optimize the pricing mechanism of maintenance service contract and achieve a win-win *** experiments are *** results show that by taking into account the incentive and penalty mechanisms,the revenue can be improved for both the customers and ***,with the increase of repair rate and improvement factor in the preventive maintenance,the revenue will increase gradually for both the parties.

关键词： maintenance service contract Nash game incentive and penalty mechanism corrective maintenance preventive maintenance

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Study on viscosity mechanism of caffeine crystallization solutions Author links open overlay panel

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Particuology 2024年第8期91卷 341-350页

作者： Linjing Yu Min su School of Chemical Engineering Hebei University of TechnologyTianjin300130China

The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation ***,it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization,ensuring a seamless production ***,the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model *** investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and *** results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization ***,caffeine crystals possess elongated needle-like shapes,featuring a substantial specific surface ***,there isπ-πstacking occurring between the(200)crystal face and(110)crystal face,effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis,resulting in a more viscous crystallization *** results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.

关键词： Crystallization Caffeine Viscosity mechanism Molecular simulation

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A Time-Domain Numerical Simulation for Free Motion Responses of Two Ships Advancing in Head Waves

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China Ocean Engineering 2024年第3期38卷 519-530页

作者： PAN su-yong CHENG Yong School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward *** solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water *** provides conditions for adding artificial damping *** the Runge−Kutta method to solve equations related to *** upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves *** the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be *** constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head *** simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head *** further investigations are conducted on the effects of different ship types on the motion response.

关键词： ship motions time domain simulation forward speed different distances wave loads

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Synthesis and characterization of unsymmetric silylated PNP single-active central chromium catalyst

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分子科学学报 2024年第2期40卷 182-188页

作者： CHEN peili SONG Da LI Yang GUO Lijun su Qiucheng LI Cuiqin Guangzhou Institute of Energy Resources Chinese Academy of SciencesGuangzhou 510640China University of Science and Technology of China Hefei 230026China Provincial Key Laboratory of Polyolefin New Materials College of Chemistry and Chemical EngineeringNortheast Petroleum UniversityDaqing 163318China

A silylated PNP ligand with asymmetric structure was synthesized using(γ-aminopropyl)triethoxysilane and chlorodiphenyl phosphine as raw *** optimal synthetic conditions of the PNP ligand were obtained by conditional experiments and were as follows:dichloromethane was solvent,triethylamine was acid acceptor,the mole ratio of chlorodiphenylphosphine and(γ-aminopropyl)triethoxysilane was 2.1∶1,the dropping temperature of chlorodiphenylphosphine was-5℃,the dropping time was 30 min,the reaction temperature was 25℃and the reaction time was 12 *** the conditions,the yield of the silylated PNP ligand was 91.20%.Based on grey correlation analysis,the dropping temperature was the main factor for the yield of the silylated PNP *** single-active central chromium catalyst based on the silylated PNP ligand was synthesized by complexation reaction with the silylated PNP ligand and chromium chloride tetrahydrofuran complex as materials,and the yield was 95.25%.The chemical structures of the silylated PNP ligand and the corresponding chromium catalyst were confirmed by elemental analysis,FT-IR,^(1)H NMR,MS and *** single-active central chromium catalyst based on the silylated PNP ligand had good catalytic activity for ethylene oligomerization,and the content of C_(8)olefin was 72.40%,which was superior to Si-Schiff-Cr based on intermolecular coordination.

关键词： unsymmetric silylated PNP ligand grey association chromium catalyst ethylene oligomerization

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Numerical simulation of microwave-induced cracking and melting of granite based on mineral microscopic models

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1512-1524页

作者： Xiaoli su Diyuan Li Junjie Zhao Mimi Wang Xing su Aohui Zhou School of Resources and Safety Engineering Central South UniversityChangsha 410083China

This study introduces a coupled electromagnetic–thermal–mechanical model to reveal the mechanisms of microcracking and mineral melting of polymineralic rocks under microwave *** tests validate the rationality of the proposed *** microscopic mineral sections into the granite model for simulation shows that uneven temperature gradients create distinct molten,porous,and nonmolten zones on the fracture ***,the varying thermal expansion coefficients and Young's moduli among the minerals induce significant thermal stress at the mineral *** and biotite with higher thermal expansion coefficients are subjected to compression,whereas plagioclase with smaller coefficients experiences tensile *** the molten zone,quartz undergoes transgranular cracking due to theα–βphase *** local high temperatures also induce melting phase transitions in biotite and *** numerical study provides new insights into the distribution of thermal stress and mineral phase changes in rocks under microwave irradiation.

关键词： microwave numerical modeling microcracking phase change granite

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Stochastic and Distributed Optimal Energy Management of Active Distribution Networks Within Integrated Office Buildings

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 504-517页

作者： Zening Li su su Xiaolong Jin Mingchao Xia Qifang Chen Koji Yamashita National Active Distribution Network Technology Research Center Beijing Jiaotong UniversityBeijing 100044China Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin 300072China Electrical and Computer Engineering University of California RiversideCA92521USA.

This paper proposes a stochastic and distributed optimal energy management approach for active distribution networks(ADNs)within office *** proposed approach aims at scheduling office buildings fitted with heating ventilation and air conditioning(HVAC)systems,and electric vehicle(EV)charging piles,to participate in the ADN ***,an energy management approach for the ADN with aggregated office buildings is *** the ADN optimization model is formulated considering the detailed building thermal dynamics and the mobile behaviors of ***,to consider un-certainties of photovoltaic(PV)power,scenario-based stochastic programming is integrated into the ADN optimization *** further realize the stochastic energy management of the ADN within office buildings in a distributed manner,the alternating direction method of multipliers(ADMM)is used to solve the ADN optimization *** original ADN optimization problem is divided into the network-side and the building-side sub-problems to effectively protect the privacy of the ADN and the office ***,the ADN optimization model incorporating office buildings is validated in the winter by numerical *** addition,the impacts of comfort temperature range and expected state of charge(SOC)at departure are *** Terms—ADN,EV,HVAC system,Office building,Stochastic and distributed energy management.

关键词： ADN EV HVAC system Office building Stochastic and distributed energy management

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