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Advances in alimentary tract imaging

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World Journal of Gastroenterology 2006年第20期12卷 3139-3145页

作者： dean DT Maglinte Kumaresan Sandrasegaran Mark Tann Department of Radiology Indiana University School of Medicine IndianapolisUnited States

in imaging techniques are changing the way radiologists undertake imaging of the gastrointestinal tract and their ability to answer questions posed by surgeons. In this paper we discuss the technological improvements of imaging studies that have occurred in the last few years and how these help to better diagnosing alimentary tract disease.

关键词： Imaging Alimentary tract

Pseudo feature point registration of pavement images

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Journal of Traffic and Transportation Engineering(English Edition) 2018年第4期5卷 254-267页

作者： dean Wright Ginger Lehmann UK Leamington Spa CV31 1PR UK

Over the last 20 years road pavement imaging has become a routine output from annual pavement assessment survey regimes across the world. Hitherto the traditional use of road pavement images in road condition assessment has been crack detection, rather than direct analysis of image features such as aggregate loss, changes in surface texture or deterioration of road markings. Any attempt to assess pavement condition change from features in a sequence of such images captured months or years apart requires image registration. A method for registering road pavement images is presented that makes use of an affine transformation based on pseudo-features within images. An affine trans- formation is considered suitable for registering road pavement images because of the linear way in which pavements are surveyed. Pseudo feature points are found using a modified corner detector, and then matching points between reference and template im- ages established via a correlation analysis of pavement image texture. With 4 such points it is possible to establish an affine transformation between the images. The method is tested on pavement images captured on three UK sites between winter 2014/15 and 2015/16. The method successfully registered 98% of images captured on sites typical of the UK＇s strategic road network, and 65% of images captured on a site typical of the UK＇s minor road network.

关键词： Pavement engineering Pavement texture Image registration Pseudo feature point

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Chinese Annals of Mathematics,Series B 2002年第2期23卷 187-204页

作者： E.J.dean R.GLOWINSKI DepartmentofMathematicsUniversitofHouston Departmentof MathematicsUniversity of Houston 651 P.G.HoffmanHallHoustonTX 77204-3008US

This article discusses computational methods for the numerical simulation of unsteady Bingham visco-plastic flow. These methods are based on time-discretization by operator-splitting and take advantage of a characterization of the solutions involving some kind of Lagrange multipliers. The full discretization is achieved by combining the above operator-splitting methods with finite element approximations, the advection being treated by a wave-like equation 'equivalent' formulation easier to implement than the method of characteristics or high order upwinding methods. The authors illustrate the methodology discussed in this article with the results of numerical experiments concerning the simulation of wall driven cavity Bingham flow in two dimensions.

关键词： Bingham visco-plastic flow Operator-splitting methods Finite element

超声背散射法在孕妇松质骨骨密度测量中的应用价值

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医学临床研究 2024年第2期41卷 185-187,191页

作者：白博周毓青他得安上海市长宁区妇幼保健院超声医学科上海200040 华东师范大学附属妇幼保健院超声医学科上海200040 复旦大学电子工程系上海200433

【目的】探讨超声背散射法在孕妇松质骨骨密度(BMD)测量中的应用价值。【方法】选取2017年6月至2018年7月在上海市长宁区妇幼保健院进行常规产检的235例孕妇,所有孕妇同时采用超声背散射法与超声透射法测量松质骨的BMD与超声传导速度(SO... 详细信息

【目的】探讨超声背散射法在孕妇松质骨骨密度(BMD)测量中的应用价值。【方法】选取2017年6月至2018年7月在上海市长宁区妇幼保健院进行常规产检的235例孕妇,所有孕妇同时采用超声背散射法与超声透射法测量松质骨的BMD与超声传导速度(SOS),比较两种方法测量结果的差异;根据孕周不同将所有孕妇分为早孕组(28周)三组,比较不同孕周孕妇超声背散射法测量的BMD与SOS。【结果】超声背散射法、超声透射法测量的孕妇BMD与SOS比较,差异无统计学意义(P>0.05)。早孕组超声背散射法所测BMD与SOS值明显高于中孕组与晚孕组(P<0.05),且中孕组明显高于晚孕组(P<0.05)。【结论】超声背散射法测量的BMD、SOS与超声透射法测量值比较,差异无统计学意义,可反映孕妇BMD随孕周的变化,可用于临床监测孕妇BMD。

关键词：孕妇松质骨/影像诊断骨密度

Preparation of porous polyamide 6(PA6)membrane with copper oxide(CuO)nanoparticles selectively localized at the wall of the pores via reactive extrusion

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Nano Materials Science 2022年第2期4卷 169-177页

作者： Tianqi Liang Jie Liu Zhaoyang Wei dean Shi Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei Key Laboratory of Polymer MaterialsSchool of Materials Science and EngineeringHubei UniversityWuhan430062PR China

In this study,CuO nanoparticles are pre-modified with styrene-maleic anhydride copolymers(SMAs)of different molecular weights and MAH *** the pre-modified CuO nanoparticles(CuO-SMAs)are added to the PA6/SEBS(Styrene Ethylene Butylene Styrene copolymer)(40/60 wt/wt)polymer blends with a co-continuous *** SMA3(MAH=8 wt%,M_(n)=250000 g/mol)is used to modify CuO nanoparticles,and the grafting degree of SMA3 on the surface of CuO reaches 2.74 wt%,90.71%of the added mCuO-SMA3 nanoparticles can be located at the interface of PA6 and SEBS.A porous PA6 membrane with CuO nanoparticles located at the pore walls can be obtained after the SEBS phase is etched with *** catalytic reaction velocity constant(k)for the reduction of p-nitrophenol in NaBH_(4)solutions with the PA6/mCuO-SMA3 porous membrane can reach 1.0040 min^(-1).This work provides a feasible and straightforward method for the preparation of porous polymer membranes with functional nanoparticles located at the wall of the pores.

关键词： Co-continuous CuO nanoparticles Selective distribution Porous PA6 membrane Catalytic performance

Evaluation of hydro-mechano-chemical behaviour of bentonite-sand mixtures

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第2期14卷 637-652页

作者： Wenjing Sun Cheng Liu Diansen Yang dean Sun Department of Civil and Energy Engineering College of Environmental Science and EngineeringDonghua UniversityShanghai201620China Institute for the Conservation of Cultural Heritage Shanghai UniversityShanghai200444China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Shanghai Construction Group Co. Ltd.Shanghai200080China Department of Civil Engineering School of Mechanics and Engineering ScienceShanghai UniversityShanghai200444China

Bentonite-sand mixtures are widely used in engineering barrier of deep geological disposal of high-level radioactive nuclear waste and anti-seepage barrier of civil geotechnical *** the action of groundwater solution infiltration and external stress,the hydro-mechanical(HM)behaviour of bentonitesand mixtures,*** swelling characteristics and permeability,will *** the anti-seepage and filtration effect is weakened or lost,the pollutants will spread to the ***,it is necessary to study the swelling characteristics and permeability of bentonite-sand mixtures under coupled mechanochemical(MC)effect and to establish corresponding prediction *** this reason,swelling tests under salt solution with different concentrations are conducted on pure bentonite and its mixtures with 30%,70%and 90%sand contents,the compression tests are carried out on saturated samples,and the saturated permeability coefficient k of the sample under each load is calculated by Terzaghi’s one-dimensional consolidation *** concepts of true effective stress pe,montmorillonite void ratio em and critical sand content as are introduced to determine the em-pe relationship and finally the k-em relationship of bentonite-sand *** is found that when the sand content aas,the em-pe relationship of the mixture is linear and independent of the salt solution concentration,and when a>as,the em-pe relationship of bentonite-sand mixture is bi-linear with the true effective deviatoric stress pesa as the *** addition,the em-k relationship also shows the linear trend when aas,and the slope of the line increases with the increase of the salt solution *** a>as,the k-em relationship will deviate from the linear ***,the larger the sand content is,the farther the deviation *** the basis of summing the regularity,a model for predicting the HM behaviour of bentonite-sand mixture under the coupled MC effect is proposed.B

关键词： Bentonite-sand mixture Hydro-mechano-chemical(HMC)behaviour Salt solution True effective stress

Cylindrical cavity expansion responses in anisotropic unsaturated soils under plane stress condition

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1989-2002页

作者： Haohua Chen Xiaolin Weng Lele Hou dean Sun Department of Geotechnical Engineering Tongji UniversityShanghai200092China Department of Civil and Architectural Engineering and Mechanics University of ArizonaTucsonAZ85721USA School of Highway Chang’an UniversityXi’an710064China Department of Civil Engineering Shanghai UniversityShanghai200444China

In this paper,an anisotropic critical state model for saturated soils was extended to unsaturated conditions by introducing suction into its yield *** this model with soil-water characteristic curves related to porosity ratio was employed to characterize the coupled hydromechanical behavior of unsaturated anisotropic *** on the plane stress condition,the problem of the cylindrical cavity expansion in unsaturated anisotropic soils was transformed into first-order differential equations using the Lagrangian *** equations were solved as an initial value problem using the Runge-Kutta algorithm,which can reflect the soil-water retention behavior during cavity *** analyses were conducted to investigate the influences of overconsolidation ratio(OCR),suction,and degree of saturation on the expansion responses of a cylindrical cavity in unsaturated anisotropic soil under plane stress *** results show that the above factors have obvious influences on the cavity responses,and the plane strain solution tends to overestimate expansion pressure and degree of saturation but underestimates suction around the cavity compared to the proposed plane stress *** theoretical model proposed in this paper provides a reasonable and effective method for simulating pile installation and soil pressure gauge tests near the ground surface of the unsaturated soils.

关键词： Cylindrical cavity Anisotropic unsaturated soil Plane stress Hydromechanical behavior

Experimental and numerical study of the adsorption performance of a vortex suction device using water-swirling flow

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Science China(Technological Sciences) 2020年第6期63卷 931-942页

作者： ZHU YaWei ZHOU RenGuan YANG Gang ZHU YanQing HU dean State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China College of Electrical and Information Engineering Hunan UniversityChangsha 410082China

An electrically activated underwater suction device is designed to form an amazing amount of negative pressure by generating water swirling flow,which can make underwater wall-climbing robot stick to the wall surface allowing a ground *** the purpose of a full understanding of the mechanism of the suction device,a series of experimental tests are carried out and a computational fluid dynamics(CFD)model is *** results show that the suction force F is consistent between experimental tests and *** insight into the flow phenomena of vortex suction device,including spatial velocity and pressure distribution,is given through numerical simulation ***,the crucial parameters,i.e.,the rotation speedωand gap clearance h,are *** the relationships of F-ωand F-h are *** reveals that with the increasing of rotation speed,the suction force increases *** with the increasing of gap clearance,the suction force increases firstly and then decreases,so that a reasonable design interval of gap clearance can be got to obtain the required suction force for the engineering applications.

关键词： vortex suction device hydrodynamic analysis swirling flow underwater wall-climbing robot CFD

Design,Characterization and Optimization of Multi-directional Bending Pneumatic Artificial Muscles

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Journal of Bionic Engineering 2021年第6期18卷 1358-1368页

作者： Wei Xiao dean Hu Weixiong Chen Gang Yang Xu Han State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082People’s Republic of China Key Laboratory of Advanced Design and Simulation Techniques for Special Equipment Ministry of EducationHunan UniversityChangsha410082People’s Republic of China School of Mechanical Engineering Hebei University of TechnologyTianjin300401People’s Republic of China

Bending Pneumatic Artificial Muscles(PAMs)are particularly attractive and extensively applied to the soft grasper,snake-like robot,*** extend the application of PAMs,we fabricate a Multi-directional Bending Pneumatic Artificial Muscle(MBPAM)that can bend in eight directions by changing the pressurized *** maximum bending angle and output force are 151°and 0.643 N under the pressure of 100 kPa,***,the Finite Element Model(FEM)is established to further investigate the *** experimental and numerical results demonstrate the nonlinear relationship between the pressure and the bending angle and output ***,the effects of parameters on the performance are studied with the validated *** results reveal that the amplitude of waves and the thickness of the base layer can be ***,multi-objective optimization is performed to improve the bending performance of the *** optimization results indicate that the output force can be increased by 7.8%with the identical bending angle of the initial design,while the bending angle can be improved by 8.6%with the same output ***,the grasp tests demonstrate the grip capability of the soft four-finger gripper and display the application prospect of the MBPAM in soft robots.

关键词： Pneumatic artificial muscle Multi-directional bending Soft robots Parameter optimization