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泥水盾构掘进过程中的泥水劈裂现象现场试验研究（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第7期15卷 465-481页

作者： Xue-yan LIU da-jun yuan School of Civil Engineering Beijing Jiao Tong University Tunnel and Underground Engineering Research Center of Ministry of Education Beijing Jiao Tong University

研究目的:本文通过研究泥水在地层中的劈裂和伸展现象,给出一种地层劈裂抗力的测定方法,从而为泥水盾构掘进过程中泥水压力设定提供参考,防止盾构掘进过程中泥水喷发现象的发生。创新要点:1.给出了地层劈裂抗力的测定方法,并通过现场试... 详细信息

研究目的:本文通过研究泥水在地层中的劈裂和伸展现象,给出一种地层劈裂抗力的测定方法,从而为泥水盾构掘进过程中泥水压力设定提供参考,防止盾构掘进过程中泥水喷发现象的发生。创新要点:1.给出了地层劈裂抗力的测定方法,并通过现场试验和理论分析得出该方法是可靠的;2.建立了考虑泥水粘性和比重的地层劈裂伸展模型,该模型对现场试验结果有较好的预测;3.结合地层劈裂抗力和泥水劈裂伸展特性给出了盾构掘进过程中泥水压力的设定上限。研究方法:基于现场泥水劈裂试验,通过试验结果分析和理论分析,建立了劈裂压力和劈裂伸展压力的计算模型。通过泥水和地层参数对计算模型的影响分析,给出泥水盾构掘进过程中泥水配比和压力设定选择建议。重要结论:1.本文描述的现场泥水劈裂仪可以用于地层劈裂抗力的测定;2.使用总应力法的劈裂模型能够很好的预测地层的初始劈裂压力;3.考虑泥水粘性和比重的地层劈裂伸展模型对现场试验结果有较好的预测;4.在劈裂伸展的过程中,具有更大比重和粘性的泥水有利于阻止劈裂的进一步伸展,但是对初始劈裂压力的影响不大。5.在实际盾构掘进过程中,泥水劈裂发生后很难阻止其伸展。因此,防止泥水喷发的关键措施在于设定泥水压力上限防止泥水劈裂。

关键词：现场泥水劈裂试验初始劈裂压力劈裂伸展劈裂伸展压力泥水盾构隧道施工

P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures

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Petroleum Science 2024年第1期21卷 143-161页

作者： Sheng-Qing Li Wen-Hao Wang yuan-da Su jun-Xin Guo Xiao-Ming Tang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Laoshan National Laboratory Qingdao 266071ShangdongChina Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and TechnologyShenzhen 518055GuangdongChina Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055GuangdongChina

P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned ***,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic ***,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the *** Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and *** then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy *** results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave *** coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV *** oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV *** a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.

关键词： Aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow

Comparison of irradiation-induced void formations in tungsten with equiaxed and columnar structures

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Tungsten 2024年第4期6卷 794-805页

作者： Liu Xi Jia-jun Zhao Ji-jun Zhao yuan-yuan Wang Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education) Dalian University of Technology

Tungsten(W) has been received much attention,since it is regarded as one of the most promising plasma facing materials for fusion *** are two typical morphologies of unirradiated polycrystalline W,which have the equiaxed and columnar grains,***,the role of arrangement of grain boundary(GB) in absorbing irradiation-generated point defects is still waiting to be *** current investigation,irradiation-induced void formations in W with equiaxed and columnar microstructures are predicted,respectively,using the developed phase-field *** significant kinetic behavior,such as the generation and annihilation of point defects and the interaction between point defects and GB,is reasonably *** density,size and porosity of void formed in these two microstructures are examined and analyzed according to the effects of GB ratio,temperature and damage *** analytical results show that higher GB ratio can effectively reduce void porosity,and the columnar-grained structure has better irradiation resistance than that of the equiaxed one in the case of small grain *** importantly,the predicted void sizes changed with temperature and damage rate agree well with the experimentally measured *** work has a more beneficial contribution to the microstructural improvement of International Thermonuclear Experimental Reactor-grade W.

关键词： Grain morphology Irradiation-induced void Phase-field Tungsten

The Uptake and Distribution Evidence of Nano-and Microplastics in vivo after a Single High Dose of Oral Exposure

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Biomedical and Environmental Sciences 2024年第1期37卷 31-41页

作者： HONG Tao SUN Wei DENG yuan LYU Jian da JIN Cui Hong BAI Ying Long NA jun ZHANG Rui GAO yuan PAN Guo Wei YANG Zuo Sen YAN Ling jun Research Center for Universal Health School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Department of Pain Management Shengjing Hospital of China Medical UniversityShenyang 110004LiaoningChina Department of Toxicology School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Department of Maternal and Child Health School of Public HealthChina Medical UniversityShenyang 110122LiaoningChina Institute of Preventive Medicine China Medical UniversityShenyang 110122LiaoningChina Institute of Chronic Diseases Liaoning Provincial Center for Disease Control and PreventionShenyang 110000LiaoningChina

Objective Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in *** Fluorescent microspheres(100 nm,3μm,and 10μm)were given once at a dose of 200 mg/(kg∙body weight).The fluorescence intensity(FI)in observed organs was measured using the IVIS Spectrum at 0.5,1,2,and 4 h after *** was performed to corroborate these *** In the 100 nm group,the FI of the stomach and small intestine were highest at 0.5 h,and the FI of the large intestine,excrement,lung,kidney,liver,and skeletal muscles were highest at 4 h compared with the control group(P<0.05).In the 3μm group,the FI only increased in the lung at 2 h(P<0.05).In the 10μm group,the FI increased in the large intestine and excrement at 2 h,and in the kidney at 4 h(P<0.05).The presence of nano-/microplastics in tissues was further verified by *** peak time of nanoplastic absorption in blood was *** Nanoplastics translocated rapidly to observed organs/tissues through blood circulation;however,only small amounts of MPs could penetrate the organs.

关键词： Microplastics Nanoplastics IVIS Spectrum small-animal imaging system Tissue distribution Blood

An alternative 2D ICEEMdaN-based denoising method and its application in processing magnetic anomaly data

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Geodesy and Geodynamics 2024年第5期15卷 465-476页

作者： jun Xu Jinsong Du Changqing yuan School of Geophysics and Geomatics China University of GeosciencesWuhan 430074China Hubei Subsurface Multi-scale Imaging Key Laboratory China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China Key Laboratory of Geological Survey and Evaluation of Ministry of Education China University of GeosciencesWuhan 430074China

Due to environmental noise and human factors,magnetic data collected in the field often contain various noises and interferences that significantly affect the subsequent data processing and *** Mode Decomposition(EMD),an adaptive multiscale analysis method for nonlinear and non-stationary signals,is widely used in geophysical and geodetic data *** with traditional EMD,Improved Complete Ensemble EMD with Adaptive Noise(ICEEMdaN)is more effective in addressing the problem of mode *** on the principles of 1D ICEEMdaN,this paper presents an alternative algorithm for 2D ICEEMdaN,extending its application to two-dimensional *** effectiveness of the proposed approach is demonstrated through synthetic signal experiments,which show that the 2D ICEEMdaN exhibits a weaker mode mixing effect compared to the traditional bidimensional EMD(BEMD)***,to improve the performance of the denoising method based on 2D ICEEMdaN and preserve useful signals in high-frequency components,an improved soft thresholding technique is *** magnetic anomaly data testing indicates that our denoising method effectively preserves signal continuity and outperforms traditional soft thresholding *** validate the practical application of this improved threshold denoising method based on 2D ICEEMdaN,it is applied to ground magnetic survey data in the Yandun area of *** results demonstrate the effectiveness of the method in removing noise while retaining essential information from practical magnetic anomaly *** particular,practical applications suggest that 2D ICEEMdaN can extract trend signals more accurately than the *** conclusion,as a potential tool for multi-scale decomposition,the 2D ICEEMdaN is versatile in processing and analyzing 2D geophysical and geodetic data.

关键词： 2D ICEEMdaN Mode mixing effect Magnetic anomaly Denoising Improved soft thresholding

Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming Xia Yong-jun Ye Shu-yuan Liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the *** these measurement methods,the closed-loop method is frequently ***,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation *** CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and *** this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the *** consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was *** effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were *** on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion *** CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

Spectral Fittings of Warm Coronal Radiation with High Seed Photon Temperature:Apparent Low-temperature and Flat Soft Excess in AGNs

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Research in Astronomy and Astrophysics 2024年第7期24卷 135-144页

作者： Ze-yuan Tang jun-Jie Feng jun-Hui Fan School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China Key Laboratory for Astronomical Observation and Technology of Guangzhou Guangzhou 510006China

A warm corona has been widely proposed to explain the soft excess(SE)in X-ray above the 2-10 ke V power law extrapolation in Active Galactic Nuclei(AGNs).In actual spectral fittings,the warm coronal seed photon temperature(T_s)is usually assumed to be far away from the soft X-ray,but kT_scan reach close to 0.1 ke V in the standard accretion disk *** this study,we used Monte Carlo simulations to obtain radiation spectra from a slab-like warm corona and fitted the spectra using the spherical-geometry-based routine THCOMP or a thermal *** findings reveal tha high T_scan influence the fitting results.A moderately high kT_s(around 0.03 ke V)can result in an apparent low-temperature and flat SE,while an extremely high kT_s(around 0.07 ke V)can even produce an unobserved blackbody-like *** conclusions indicate that,for spectral fittings of the warm coronal radiation(SE in AGNs),kT_sshould be treated as a free parameter with an upper limit,and an accurate coronal geometry is necessary when kT_s>0.01 ke V.

关键词： galaxies active-accretion-accretion disks-black hole physics

Effect of heat treatment on microstructure and mechanical properties of selective laser-melted PH13-8Mo stainless steel

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Journal of Iron and Steel Research International 2024年第4期31卷 945-955页

作者： yuan Zhang Xiang Liu Chang-jun Wang Chang Liu School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

PH13-8Mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode *** formed parts with ultra-high purity were manufactured by selective laser *** tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat *** microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron *** characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,*** formed parts are mainly composed of martensite and retained ***,the NiAl and M23C precipitates form,which are the major strengthening phases of PH13-8Mo stainless *** optimal heat treatment process is 925℃×1 h water cooling(WC)+0℃×2 h air cooling(AC)+540℃×4 h *** this heat treatment process,PH13-8Mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 MPa,1432 MPa and 63 J,*** strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and M23Co precipitates and the change of volume fraction of the retained austenite.

关键词： High-strength stainless steel-Selective laser melting-Heat treatment Microstructure Mechanical property

On the Difference Between the Skew-rank of an Oriented Graph and the Rank of Its Underlying Graph

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 129-136页

作者： Jia-min Zhu Bo-jun yuan Yi Wang School of Mathematical Sciences Anhui UniversityHefei230601China School of Science Zhejiang University of Science and TechnologyHangzhou310023China

Let G be a simple graph and G~σ be the oriented graph with G as its underlying graph and orientation σ.The rank of the adjacency matrix of G is called the rank of G and is denoted by r(G).The rank of the skew-adjacency matrix of G~σ is called the skew-rank of G~σ and is denoted by sr(G~σ).Let V(G)be the vertex set and E(G) be the edge set of *** cyclomatic number of G,denoted by c(G),is equal to |E(G)|-|V(G)|+ω(G),where ω(G) is the number of the components of *** is proved for any oriented graph G~σ that-2c(G)≤sr(G~σ)-r(G)≤2c(G).In this paper,we prove that there is no oriented graph G~σwith sr(G~σ)-r(G)=2c(G)-1,and in addition,there are infinitely many oriented graphs G~σ with connected underlying graphs such that c(G)=k and sr(G~σ)-r(G)=2c(G)-l for every integers k,l satisfying 0 ≤l≤4k and l≠1.

关键词： cyclomatic number rank skew-rank