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Mechanics model and numerical analysis of floor heave in soft rock roadway

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Journal of Coal Science & Engineering(China) 2011年第4期17卷 372-376页

作者： ZHU Chuan-qu wang Yong CHEN Miao-ming CHEN Zhi wang Hong-ming Hunan Key Laboratory of Safe Mining Techniques of Coal Mines Hunan University of Science and Technology Xiangtan411201 China

The mechanism of floor heave was analyzed by establishing mechanics models and solving differential equations. The amount of floor heave is proportional to the abutment pressure of surrounding rock, roadway width, and the distance of support pressure peak to the roadway and is inversely proportional to the elastic modulus of floor rock. Using FLAC2D to simulate floor rock grouting in soft rock roadway verifies the active role of floor rock grouting in the floor controlling of soft rock roadway; floor rock grouting and grouting range directly impact on the stability scope of surrounding rock, namely, with the increase of grouting range, the subsidence of roof, the approach of both sides, and the amount of floor heave decreased gradually, the stability of surrounding rock is enhanced

关键词： soft rock roadway floor heave floor rock grouting numerical simulation

Determining Sets and Determining Numbers of Finite Groups

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Algebra Colloquium 2024年第1期31卷 111-128页

作者： Dengyin wang Chi Zhang Haipeng qu School of Mathematics China University of Mining and Technology XuzhouJiangsu 221116China School of Mathematics and Computer Science Shanxi Normal University LinfenShanxi 041000China

A subset D of a group G is a determining set of G if every automorphism of G is uniquely determined by its action on D,and the determining number of G,a(G),is the cardinality of a smallest determining set.A group G is called a DEG-group if α(G)equals(G),the generating number of *** main results are as *** groups with determining number 0 or 1 are classified;finite simple groups and finite nilpotent groups are proved to be DEG-groups;for a given finite group H,there is a DEG-group G such that H is isomorphic to a normal subgroup of G and there is an injective mapping from the set of all finite groups to the set of finite DEG-groups;for any integer k≥2,there exists a group G such that α(G)=2 and(G)≥k.

关键词： determining number automorphisms nilpotent groups

Novel preparation of NaA/carbon nanocomposite thin films with high permeance for CO_2/CH_4 separation

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Chinese Chemical Letters 2007年第4期18卷 455-457页

作者： Zhi Hui Zhou Jian Hua Yang Li Feng Chang Yan Zhang Wei Guo Sun Jin qu wang State Key Laboratory of Fine Chemicals Institute of Adsorption and Inorganic Membrane Dalian University of Technology Dalian 116012 PR China

Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous α-Al2O3 substrate by incorporating nanosized NaA zeolite into novolak-type phenolic resin. The prepared films were characterized by XRD, SEM and single gas permeation tests. The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO2/CH4 was 28.4 and the carbon dioxide flux was 3.39 ×10^-7 mol/（Pa m^2 s） at room temperature and under a pressure difference of 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those of composite films. From the SEM images, the films were continuous and highly intergrown. Compared with carbon membranes, the thickness of nanocomposite films was drastically decreased, which was helpful to reduce the diffusion resistance and increase the flux of gas permeance.

关键词： Nanocomposite Thin films High performance Gas separation

Network Configuration Entity Extraction Method Based on Transformer with Multi-Head Attention Mechanism

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Computers, Materials & Continua 2024年第1期78卷 735-757页

作者： Yang Yang Zhenying qu Zefan Yan Zhipeng Gao Ti wang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing100876China Product Development Department China Unicom Smart City Research InstituteBeijing100044China

Nowadays,ensuring thequality of networkserviceshas become increasingly *** are turning toknowledge graph technology,with a significant emphasis on entity extraction in the identification of device *** research paper presents a novel entity extraction method that leverages a combination of active learning and attention ***,an improved active learning approach is employed to select the most valuable unlabeled samples,which are subsequently submitted for expert *** approach successfully addresses the problems of isolated points and sample redundancy within the network configuration sample *** the labeled samples are utilized to train the model for network configuration entity ***,the multi-head self-attention of the transformer model is enhanced by introducing the Adaptive Weighting method based on the Laplace mixture *** enhancement enables the transformer model to dynamically adapt its focus to words in various positions,displaying exceptional adaptability to abnormal data and further elevating the accuracy of the proposed *** comparisons with Random Sampling(RANDOM),Maximum Normalized Log-Probability(MNLP),Least Confidence(LC),Token Entrop(TE),and Entropy query by Bagging(EQB),the proposed method,Entropy query by Bagging and Maximum Influence Active Learning(EQBMIAL),achieves comparable performance with only 40% of the samples on both datasets,while other algorithms require 50% of the ***,the entity extraction algorithm with the Adaptive Weighted Multi-head Attention mechanism(AW-MHA)is compared with BILSTM-CRF,Mutil_Attention-Bilstm-Crf,Deep_Neural_Model_NER and BERT_Transformer,achieving precision rates of 75.98% and 98.32% on the two datasets,*** tests demonstrate the statistical significance and effectiveness of the proposed algorithms in this paper.

关键词： Entity extraction network configuration knowledge graph active learning transformer

Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine

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China Ocean Engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU Wan-li wang Pi-guang qu Yang DU Xiu-li Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field

Analytical Solution and Simplified Formula for Added Mass of Horizontal and Vertical Motions of Truncated Cylinders Under Earthquake Action

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China Ocean Engineering 2024年第1期38卷 54-67页

作者： wang Pi-guang LYU Si-yu qu Yang ZHAO Mi DU Xiu-li State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of Tech-nologyBeijing 100124China

This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water *** governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible *** governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary *** analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite *** main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion *** added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering *** calculation results show that the simplified formulas are in good agreement with the analytical solutions.

关键词： earthquake hydrodynamic pressure truncated cylinder added mass simplified formula

Effects of serum proteins on corrosion rates and product bioabsorbability of biodegradable metals

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Regenerative Biomaterials 2024年第1期3卷 132-148页

作者： Hongjie Zhang Xin Li Zehua qu Wanqian Zhang qunsong wang Dinglingge Cao Yaoben wang Xin wang Yang wang Lin Yu Jiandong Ding State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200438China

Corrodible metals are the newest kind of biodegradable materials and raise a new problem of the corrosion ***,the removal of the precipitated products has been unclear and even largely ignored in ***,we find that albumin,an abundant macromolecule in serum,enhances the solubility of corrosion products of iron in blood mimetic Hank’s solution *** is universal for other main biodegradable metals such as magnesium,zinc and polyester-coated *** also influences corrosion rates in diverse trends in Hank’s solution and normal *** on quantitative study theoretically and experimentally,both the effects on corrosion rates and soluble fractions are interpreted by a unified mechanism,and the key factor leading to different corrosion behaviors in corrosion media is the interference of albumin to the Ca/P passivation layer on the metal *** work has illustrated that the interactions between metals and media macromolecules should be taken into consideration in the design of the next-generation metal-based biodegradable medical devices in the formulism of precision *** improved Hank’s solution in the presence of albumin and with a higher content of initial calcium salt is suggested to access biodegradable metals potentially for cardiovascular medical devices,where the content of calcium salt is calculated after consideration of chelating of calcium ions by albumin,resulting in the physiological concentration of free calcium ions.

关键词： biodegradable metal macromolecule albumin corrosion bioabsorbability iron polylactide magnesium zinc

Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

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Rare Metals 2024年第2期43卷 780-795页

作者： Cheng-Kai Qian qu Liu Heng wang Ke-Jian Li Zhi-Peng Cai Department of Mechanical Engineering Tsinghua UniversityBeijing100084China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin300304China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China

The reliability of the coated industry components demands ideal fatigue properties of the coating,and it is mainly determined by the performance of the *** this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10Co4Cr coating,and the fatigue lifetime of the coated bolt increased by 219.82%under an imitation of the operating mode *** tests further proved that both the adhesion and cohesion strength were improved after PMT,and they benefit from the interface strengthening *** formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered *** stress was relaxed and distributed more homogeneously after PMT,and it mainly contributes to the coating/substrate *** work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.

关键词： Cemented carbide coating Pulsed magnetic treatment Interface strengthening Fatigue properties Adhesion strength

Promoting Environmental Risk Assessment and Control of Emerging Contaminants in China

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Engineering 2024年第6期37卷 13-17页

作者： Bin wang Qian Sui Huijuan Liu Gang Yu Jiuhui qu School of Environment Tsinghua UniversityBeijing 100084China School of Resources and Environmental Engineering East China University of Science and TechnologyShanghai 200237China Advanced Interdisciplinary Institute of Environmental and Ecology Beijing Normal UniversityZhuhai 519000China

*** In recent years,China has carried out an extensive preventative battle against air,water,and soil pollution,and the nation’s environmental quality-as reflected by conventional pollutant indicators—has significantly *** the same time,the issue of emerging contaminants(ECs)is beginning to receive increasing *** generally refer to newly discovered or noticeable pollutants that pose risks to the ecological environment or human *** they have not been included in environmental management,or existing management measures are insufficient to effectively prevent and control their *** ECs of greatest concern generally include persistent organic pollutants(POPs),endocrine-disrupting chemicals(EDCs),pharmaceuticals and personal care products(PPCPs),and *** four categories of ECs are not entirely separate,as they interrelate with each other(Fig.1).Chemical production and product usage are the main sources of *** is the world’s largest producer and consumer of bulk chemicals,and the production value of China’s chemical industry is predicted to reach 50%of the global total by 2030[1].Scientific control of ECs based on their environmental risk assessment is a necessary way to support the prevention and legal governance of ECs.

关键词： legal entirely prevention