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Thermo-hydro-mechanical-air coupling finite element method and its application to multi-phase problems

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Journal of Rock Mechanics and Geotechnical engineering 2014年第2期6卷 77-98页

作者： Feng Zhang Yonglin Xiong Sheng Zhang Bin Ye Department of Civil engineering Nagoya Institute of Technology Department of Civil engineering Central South University Department of Civil engineering Tongji University

In this paper, a finite element method （FEM）-based multi-phase problem based on a newly proposed thermal elastoplastic constitutive model for saturated/unsaturated geomaterial is discussed. A program of FEM named as SOFT, adopting unified field equations for thermo-hydro-mechanical-air （THMA） behavior of geomaterial and using finite element-finite difference （FE-FD） scheme for so/l-water-air three-phase coupling problem, is used in the numerical simulation. As an application of the newly proposed numerical method, two engineering problems, one for slope failure in unsaturated model ground and another for in situ heating test related to deep geological repository of high-level radioactive waste （HLRW）, are simulated. The model tests on slope failure in unsaturated Shirasu ground, carried out by Kitamura et al. （2007）, is simulated in the framework of soil-water-air three-phase coupling under the condition of constant temperature. While the in situ heating test reported by Munoz （2006） is simulated in the same framework under the conditions of variable temperature hut constant air pressure.

关键词： Multi-phase Thermo-hyd ro-mechanical-air (THMA) Finite element method (FEM) Finite deformation Constitutive model Unified field equations

Analytical Solutions for Free Vibration and Buckling of Composite Beams Using a Higher Order Beam Theory

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Acta Mechanica Solida Sinica 2016年第3期29卷 300-315页

作者： Guanghui He Dejiang Wang Xiao Yang School of Maritime and Civil engineering Zhejiang Ocean University Department of Civil engineering Shanghai University

To satisfy the interfacial shear force continuity conditions, a new model is proposed for the two-layer composite beam with partial interaction by modifying Reddy＇s higher order beam theory. The governing differential equations for free vibration and buckling are formulated using the Hamilton＇s principle, the natural frequencies and axial forces are thus analytically obtained by Laplace transform technique. The analytical results are verified through the comparison with those of several other models common in use; and the presented model is found to be a finer one than the Reddy＇s. A parametric study is also performed to investigate the effects of geometry and material parameters.

关键词： Reddy's higher order beam theory Timoshenko beam theory composite beamsfree vibration and buckling Laplace transform

Study on the High Precision Acoustic Measurement Techniques for Determining Temperature Field Around Seafloor Hydrothermal Vent

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China Ocean engineering 2012年第4期26卷 723-732页

作者：蔡勇樊炜周艳付现桥方辉金涛 Ocean Research Center of Zhoushan Zhejiang University institute of Mechatronic engineering Hangzhou Dianzi University Zhejiang Jinying Food Machinery Co. Ltd. institute of Chemical Machinery engineering Zhejiang University

This paper presents the basis of acoustic method used for temperature field measurement of seafloor hydrothermal vent and two techniques of the parabolic interpolation and the bending compensation of propagation paths of acoustic signal are introduced. Experimental research is performed to exactly rebuild the temperature field around hot springs on the floor of Qiezishan Lake, Yunnan, China. The accuracy of the travel time estimation has been improved based on the aforementioned technique and method. At the same time, by comparison of the results of temperature field with different means, the max absolute error, the maximum relative error and the root mean square error are given. It shows that the technique and the method presented in the paper can be applied to the temperature field measurement detector around the seafloor hydrothermal vent. It also has a good accuracy.

关键词： seafloor hydrothermal vent acoustic temperature method temperature field parabolic interpolation refraction of acoustic signal

Effect of Nozzle Vane and Rotor Clearance on Performance of Variable Nozzle Turbine

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Journal of Thermal Science 2022年第5期31卷 1745-1758页

作者： LEI Xinguo LI Renfu XI Zhaojun YANG Ce School of Mechanical Science and engineering Huazhong University of Science and TechnologyWuhan430074China School of Aerospace engineering Huazhong University of Science and TechnologyWuhan430074China School of Mechanical engineering Beijing Institute of TechnologyBeijing100081China

In a variable nozzle turbine(VNT),the nozzle vane and rotor clearance can generate complicated tip leakage flow,which produces a large flow loss and results in a noticeable reduction in the VNT ***,it is necessary to study the influence of the nozzle vane and rotor clearance on the VNT performance to reveal the underlying *** this study,the variation of VNT performance resulting from the nozzle vane and rotor clearance was studied numerically using the commercial CFD *** numerical results were in good agreement with the experimental *** performance under three varied clearance conditions under different clearance sizes,rotating speeds,and expansion ratios was *** conditions included the individual effect of nozzle vane clearance,the individual effect of rotor clearance,and the combined effect of nozzle vane and rotor *** results showed that the rotor clearance(clearance size equal to 0.4 mm)resulted in a certain reduction in thermal efficiency(–3.98%)and torque(–4.48%).Meanwhile,the nozzle vane hub and shroud clearance also affected the thermal efficiency(–3.66%and–13.37%,respectively)and torque(12.54%and–0.05%,respectively).Compared with the rotor clearance,the nozzle vane clearance dominated the variation in the VNT performance,and the values of the mass flow ratio,thermal efficiency,and torque increased by 12.15%,5.43%,and 8.01%,respectively(The clearance on both sides of the vane was equal to 0.2 mm.).Under the combined effect of the nozzle vane and rotor clearance,the deviation of the thermal efficiency and mass flow ratio was smaller than the sum of the values of their individual effects;when the clearance on both sides of the vane was equal to 0.2 mm and the rotor clearance was equal to 0.6 mm,the value was reduced by 2.77%and 1.71%,*** study also explains the influence mechanisms of clearance at both ends of the nozzle vane and the vane/rotor clearance interaction on the VNT perform

关键词： variation nozzle turbine tip leakage flow combined effect performance variation influence mechanisms

Modulating magnetic interface layer on porous carbon heterostructures for efficient microwave absorption

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Nano Research 2024年第11期17卷 10099-10108页

作者： Zirui Jia Lifu Sun Zhenguo Gao Di Lan School of Materials Science and engineering Hubei University of Automotive Technology Shiyan 442002 China College of Chemistry and Chemical engineering Qingdao University Qingdao 266071 China School of Materials Science and engineering Yingkou Institute of Technology Yingkou 115014 China

Modern communication systems call for high performance electromagnetic wave absorption materials capable of mitigating microwaves over a wide frequency band. The synergistic effect of structure and component regulation on the electromagnetic wave absorption capacity of materials is considered. In this paper, a new type of three-dimensional porous carbon matrix composite is reported utilizing a reasonable design of surface impedance matching. Specifically, a thin layer of densely arranged Fe-Cr oxide particles is deposited on the surface of porous carbon via thermal reduction to prepare the Fe-Cr-O@PC composites. The effect of Cr doping on the electromagnetic wave absorption performance of the composites and the underlying attenuation mechanism have been uncovered. Consequently, outstanding electromagnetic wave absorption performance has been achieved in the composite, primarily contributed by the enhanced dielectric loss upon Cr doping. Accordingly, an effective absorption bandwidth of 4.08 GHz is achieved at a thickness of 1.4 mm, with a minimum reflection loss value of −52.71 dB. This work not only provides inspiration for the development of novel absorbers with superior performance but also holds significant potential for further advancement and practical application.

关键词： microwave absorber porous carbon magnetic compounds interface layer

The Origin and System Analysis of Harmonious Management for engineering

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Frontiers of engineering Management 2015年第3期2卷 241-248页

作者： Mao-guang Lin Qian-kun Wang Hua-tao Peng Yu-dong Wang Guangzhou Military air force engineering Construction Bureau Wuhan university of Technology

engineering is a production activity aimed at increasing people's utility; however, serious crises are frequently reported to be caused by engineering constructions, both for nature and human beings. Based on engineering theories of philosophy, systems and ecology,this paper analyzed the prevailing defects of traditional project management approaches, explored the importance of harmony in engineering and engineering management,and discussed the developmental inevitability, concept connotation and system structure of harmonious management for engineering.

关键词： engineering harmony management

Mass Spectrometry-Based Human Breath Analysis:Towards COVID-19 Diagnosis and Research

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Journal of Analysis and Testing 2021年第4期5卷 287-297页

作者： Zi-Cheng Yuan Bin Hu Guangdong Provincial engineering Research Center for On-line Source Apportionment System of air Pollution Institute of Mass Spectrometry and Atmospheric EnvironmentJinan UniversityGuangzhou 510632China

COVID-19 is a highly contagious respiratory disease that can be infected through human exhaled *** breath analysis is an attractive strategy for rapid diagnosis of COVID-19 in a non-invasive way by monitoring breath *** spectrometry(MS)-based approaches off er a promising analytical platform for human breath analysis due to their high speed,specificity,sensitivity,reproducibility,and broad coverage,as well as its versatile coupling methods with different chromatographic separation,and thus can lead to a better understanding of the clinical and biochemical processes of ***,we try to review the developments and applications of MS-based approaches for multidimensional analysis of COVID-19 breath samples,including metabolites,proteins,microorganisms,and *** features of breath sampling and analysis are *** and challenges on MS-based breath analysis related to COVID-19 diagnosis and study are discussed.

关键词： COVID-19 SARS-CoV-2 Breath analysis Breath sampling Multidimensional analysis Mass spectrometry

Wireless sequential dual light delivery for programmed PDT in vivo

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Light(Science & Applications) 2024年第6期13卷 1047-1061页

作者： Jiayi Liu Bowen Sun Wenkai Li Han-Joon Kim Shu Uin Gan John S.Ho Juwita Norasmara Bte Rahmat Yong Zhang Department of Oncology The Second Xiangya HospitalCentral South UniversityChangshaHunan410011China Department of Biomedical engineering College of Design and EngineeringNational University of SingaporeSingapore117585Singapore Department of Mechanical engineering College of Design and EngineeringNational University of SingaporeSingapore117576Singapore Department of Electrical and Computer engineering College of Design and EngineeringNational University of SingaporeSingapore117583Singapore Department of Medical IT Convergence engineering Kumoh National Institute of TechnologyGumi39253Republic of Korea Department of Surgery Yong Loo Lin School of MedicineNational University of SingaporeSingapore119228Singapore The N.1 institute for Health National University of SingaporeSingapore117456Singapore institute for Health Innovation and Technology National University of SingaporeSingapore119276Singapore Department of Biomedical engineering College of EngineeringCity University of Hong KongKowloonHong Kong SARChina

Using photodynamic therapy(PDT)to treat deep-seated cancers is limited due to inefficient delivery of photosensitizers and low tissue penetration of *** nanocarriers are widely used for photosensitizer delivery,while the self-quenching of the encapsulated photosensitizers would impair the PDT ***,the generated short-lived reactive oxygen spieces(ROS)can hardly diffuse out of nanocarriers,resulting in low PDT ***,a smart nanocarrier system which can be degraded by light,followed by photosensitizer activation can potentially overcome these limitations and enhance the PDT efficacy.A light-sensitive polymer nanocarrier encapsulating photosensitizer(RB-M)was *** implantable wireless dual wavelength microLED device which delivers the two light wavelengths sequentially was developed to programmatically control the release and activation of the loaded *** transmitter coils with matching resonant frequencies allow activation of the connected LEDs to emit different wavelengths *** irradiation time,dose,and RB-M concentration were determined using an agent-based digital simulation *** vitro and in vivo validation experiments in an orthotopic rat liver hepatocellular carcinoma disease model confirmed that the nanocarrier rupture and sequential low dose light irradiation strategy resulted in successful PDT at reduced photosensitizer and irradiation dose,which is a clinically significant event that enhances treatment safety.

关键词： PDT overcome hardly

A new elliptic-parabolic yield surface model revised by an adaptive criterion for granular soils

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Science China(Technological Sciences) 2010年第8期53卷 2152-2159页

作者： LIU HanLong 1,2 ,XIAO Yang 1,2 ,LIU JinYuan 3 &LI GuoYing 4 1 Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering,Hohai university, Nanjing 210098,China 2 Geotechnical Research institute,Hohai university,Nanjing 210098,China 3Department of Civil engineering,Ryerson university,Toronto,Canada 4 Department of Geotechnical engineering,Nanjing Hydraulic Research institute,Nanjing 210014,China Key Laboratory of Ministry of Education for Geomechanics and Embankment engineering Hohai University Nanjing China Geotechnical Research institute Hohai University Nanjing China Department of Civil engineering Ryerson University Toronto Canada Department of Geotechnical engineering Nanjing Hydraulic Research Institute Nanjing China

An adaptive criterion for shear yielding as well as shear failure of soils is proposed in this paper to address the fact that most criteria,including the Mohr-Coulomb criterion,the Lade criterion and the Matsuoka-Nakai criterion,cannot agree well with the experimental results when the value of the intermediate principal stress parameter is too *** new criterion can adjust an adaptive parameter based on the experimental results in order to make the theoretical calculations fit the test results more *** original elliptic-parabolic yield surface model can capture both soil contraction and dilation ***,it normally over-predicts the soil strength due to its application of the Extended Mises criterion.A new elliptic-parabolic yield surface mode is presented in this paper,which introduces the adaptive criterion in three-dimensional principal stress *** new model can well model the stress-strain behavior of soils under general stress *** to the original model which can only simulate soil behavior under triaxial compression conditions,the new model can simulate soil behaviors under both triaxial compression conditions and general stress conditions.

关键词： principal stress space intermediate principal stress yield surface failure criterion constitutive model