检索结果-南通市图书馆

Management of human factors engineering-associated hemochromatosis: A 2015 update

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2016年第8期8卷 395-400页

作者： Menaka sivakumar Lawrie W Powell School of Medicine the University of Queensland Centre for the Advancement of Clinical Research Royal Brisbane and Women’s Hospital Campus

This review focuses on the management of iron metabolism and iron overload experienced in the hereditary condition, human factors engineering(HFE)-associated hemochromatosis. Hemochromatosis refers to a group of genetic diseases that result in iron overload; the major one globally is HFE-associated hemochromatosis. The evolution in understanding of the most common form of hereditary hemochromatosis, being the substation of cysteine to a tyrosine at position 282 in the HFE gene, has been extensively studied novel mutations in both HFE and non-HFE genes have been indicated in this disease which hold significance in its application for the Asia-Pacific region. In conditions with iron overload, the storage of excess iron in various body tissues leads to complications and toxic damage. The most common presenting complaint for this disease is malaise, lethargy and other non-specific symptoms. In order to diagnose hereditary hemochromatosis, there are biochemical, imaging and genetic testing options. Currently, cascade screening of affected families is preferred over population-level screening. The mainstay of treatment is venesection and the appropriate approach to treatment has been consolidated over the years. Recently, the indications for venesection therapy of hemochromatosis have been challenged and are the subject of ongoing research.

关键词： Human factors engineering Iron storage diseases Genetics Venesections Hemochromatosis

Investigation of weld parameters on ductility, onion ring and fracture behaviour of friction stir welded AA2219-T87

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2019年第9期26卷 2318-2327页

作者： Dinesh KUMAR R S MUTHUKUMARAn Vincent XAVIER T VEnKATESWARAn D sivakumar Department of Metallurgical and Materials Engineering NIT-Trichy 620015India Heat Treatment and Welding Metallurgy Division Vikram Sarabhai Space Centre(VSSC-ISRO)Trivandrum 695022India

Friction stir welding provides better retention of ductility and plasticity in comparison to fusion welding and it increases the stability against *** study aims to enhance both the ductility and strength of the welded *** profile was found to play an important role in retaining ductility,understanding the metal flow behavior and determining the fracture initiating *** microstructure of different regions in the onion ring was inferred to correlate the strength with the metal flow *** onion ring pattern strengthened the weld *** and taper threaded profile tool resulted in superior mechanical *** results confirmed that the fracture runs through low hardness areas such as heat affected zone and thermo-mechanically affected *** scanning electron microscopic images revealed elongated grains and dimples,justifying ductile mode of fracture.

关键词： plasticity metal flow onion ring fracture friction stir welding

Ground-Based In Situ Measurements of near-Surface Aerosol Mass Concentration over Anantapur:Heterogeneity in Source Impacts

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2013年第1期30卷 235-246页

作者： B.S.K.REDDY K.R.KUMAR G.BALAKRISHnAIAH K.R.GOPAL R.R.REDDY V.sivakumar S.Md.ARAFATH A.P.LInGASWAMY S.PAVAnKUMARI K.UMADEVI Y.n.AHAMMED Aerosol and Atmospheric Research Laboratory Department of PhysicsSri Krishnadevaraya UniversityAnantapur 515003Andhra PradeshIndia Institute of Low Temperature Science Hokkoido UniversitySapporo 0600819Japan School of Physics University of KwaZulu-NatalDurban 4000South Africa Institute of Environmental Engineering National Chiao Tung UniversityHsinchuTaiwan Department of Physics Yogi Vemana UniversityKadapa 516003India

Surface measurements of aerosol physical properties were made at Anantapur （14.62°n, 77.65°E, 331 m a.s.l）, a semiarid rural site in India, during August 2008-July 2009. Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity （RH〈75%） using a Quartz Crystal Microbalance （QCM） in the 25-0.05 um aerodynamic diameter range. The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 ug m-3, with a mean value of 34.02±9.05 ug m-3 for the entire study period. A clear diurnal pattern appeared in coarse, accumulation and nucleation-mode particle concentrations, with two local maxima occurring in early morning and late evening hours. The concentration of coarse-mode particles was high during the summer season, with a maximum concentration of 11.81±0.98 ug m-3 in the month of April, whereas accumulationmode concentration was observed to be high in the winter period contributed 〉68% to the total aerosol mass concentration. Accumulation aerosol mass fraction, Af （= Ma/Mt） was highest during winter （mean value of Af -0.80） and lowest （Af - 0.64） during the monsoon season. The regression analysis shows that both Reff and Rm are dependent on coarse-mode aerosols. The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm （AOD500） and PM2.5 mass concentration （[PM2.5]） shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.

关键词： aerosols mass concentration size distribution effective radius backward trajectories

Parametric Tolerance Analysis of Mechanical Assembly by Developing Direct Constraint Model in CAD and Cost Competent Tolerance Synthesis

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Intelligent Control and Automation 2010年第1期1卷 1-14页

作者： Govindarajalu Jayaprakash Karuppan sivakumar Manoharan Thilak Department of Mechanical Engineering Shivani College of Engineering Department of Mechanical Engineering Bannari Amman Institute of Technology Department of Mechanical Engineering T. R. P. Engineering College

The objective of tolerance analysis is to check the extent and nature of variation of an analyzed dimension or geometric feature of interest for a given GD & T scheme. The parametric approach to tolerance analysis is based on parametric constraint solving. The accuracy of simulation results is dependent on the userdefined modeling scheme. Once an accurate CAD model is developed, it is integrated with tolerance synthesis model. In order to make it cost competent, it is necessary to obtain the costtolerance relationships. The neural network recently has been reported to be an effective statistical tool for determining relationship between input factors and output responses. This study deals development of direct constraint model in CAD, which is integrated to an optimal tolerance design problem. A backpropagation (BP) network is applied to fit the costtolerance relationship. An optimization method based on Differential Evolution (DE) is then used to locate the combination of controllable factors (tolerances) to optimize the output response (manufacturing cost plus quality loss) using the equations stemming from the trained network. A tolerance synthesis problem for a motor assembly is used to investigate the effectiveness and efficiency of the proposed methodology.

关键词： Tolerance Analysis Tolerance Synthesis CAD Integration Optimization neural network

Synthesis, Structural and Dielectric Studies of nickel Substituted Cobalt-Zinc Ferrite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2010年第1期1卷 19-24页

作者： Gangatharan Sathishkumar Chidambaram Venkataraju Kandasamy sivakumar 不详

nano particles of Co(0.5-x)nixZn0.5Fe2O4 (x = 0 to 0.3) is prepared by co-precipitation method. The X-ray diffraction analysis indicates the formation of single phase ferrite particle in nano size. The lattice constant for Co0.5Zn0.5Fe2O4 is found to be 8.38 Å, but the lattice constant decreases when cobalt is replaced by nickel up to x = 0.2 content. The formation of Fe2+ in octahedral site increases the lattice constant for the concentration x = 0.3. The dielectric constant of Co0.5Zn0.5Fe2O4 is found to be less than the bulk sample. The migration of Fe3+ ion from octahedral site to tetrahedral site decreases the dielectric constant with increase in nickel concentration. The charge libration and electron hoping together form the basis for the conduction mechanism in this present compound.

关键词： Magnetic Materials Chemical Synthesis X-ray Diffraction Dielectric Properties

基于MATLAB上肢康复机械臂鲁棒控制研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

系统仿真学报 2009年第2期21卷 510-513页

作者：刘珊何际平王永骥 sivakumar Balasubramanian 电子科技大学自动化工程学院成都610054 华中科技大学控制科学与工程系武汉430074 美国亚利桑那州立大学生物工程系美国亚利桑那州85287

以穿戴上肢康复机械臂(RUPERT)的人体手臂为研究对象,对被控对象建立数学模型,推导鲁棒控制器,基于sim Mechanics建立仿真模型,实现上肢康复机械臂鲁棒控制系统。考虑到上肢康复机械臂是辅助上肢偏瘫患者进行康复训练并最大限度地诱发... 详细信息

以穿戴上肢康复机械臂(RUPERT)的人体手臂为研究对象,对被控对象建立数学模型,推导鲁棒控制器,基于sim Mechanics建立仿真模型,实现上肢康复机械臂鲁棒控制系统。考虑到上肢康复机械臂是辅助上肢偏瘫患者进行康复训练并最大限度地诱发患肢的主动作用,控制器中加入上肢偏瘫患者的主动作用,在MATLAB/Simulink的环境下运行。仿真结果表明,控制器能适应各种损伤程度的患者,在存在信号传输时延时,仍能保持响应速度和精度,具有很强的鲁棒性和自适应性。

关键词：鲁棒控制康复机械臂位置控制交互式控制

Discrete Time-Frequency Signal Analysis and Processing Techniques for non-Stationary Signals

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Applied Mathematics and Physics 2018年第9期6卷 1916-1927页

作者： S. sivakumar D. nedumaran P.G. and Research Department of Electronics Government Arts College Paramakudi Tamilnadu India Central Instrumentation and Service Laboratory University of Madras Guindy Campus Chennai India

This paper presents the methodology, properties and processing of the time-frequency techniques for non-stationary signals, which are frequently used in biomedical, communication and image processing fields. Two classes of time-frequency analysis techniques are chosen for this study. One is short-time Fourier Transform (STFT) technique from linear time-frequency analysis and the other is the Wigner-Ville Distribution (WVD) from Quadratic time-frequency analysis technique. Algorithms for both these techniques are developed and implemented on non-stationary signals for spectrum analysis. The results of this study revealed that the WVD and its classes are most suitable for time-frequency analysis.

关键词： non-Stationary Signal Short Term Fourier Transform Wigner Ville Distribution Algorithm

Phase Transition Behavior of nanocrystalline Al<sub>2</sub>O<sub>3</sub>Powders

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Soft nanoscience Letters 2013年第4期3卷 69-74页

作者： Balaraman Sathyaseelan Iruson Baskaran Kandasamy sivakumar Department of Physics Anna University Chennai Chennai India. Department of Physics Arignar Anna Govt. Arts College Cheyyar India Department of Physics University College of Engineering Arni (A Constituent College of Anna University Chennai) Arni India

Alumina (Al2O3) has been synthesized through combustion synthesis (CS) technique. The calcined products were characterized using X-ray diffractional analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo-gravimetric analysis (TGA). TG-DTA results reveal the various stages involved in transition from γ-phase to α-Al2O3 phase. The first phase γ-Al2O3 was presented in the temperature range from 600°C-875°C as deduced from the XRD patterns with cubic crystal structure. The second stage occurs in the temperature range from 900°C-1000°C. In the final step, above 1000°C, the aluminium oxide appears completely as α-Al2O3, showing high crystallinity. The particle sizes are closely related to γ- to α-Al2O3 phase transition.

关键词： nanocrystalline Al2O3 Phase Transitions γ-Al2O3 α-Al2O3 Differential Scanning Calorimetry (DSC) Electron Microscopy (TEM and SEM)

Structural, Magnetic and Dielectric Studies on Strontium Substituted nd2CuO4 System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Physics 2010年第2期1卷 93-99页

作者： Venugopalan Anbarasu Appasamy Manigandan Kandasamy sivakumar 不详

The substitution of Strontium on T'–structured nd2CuO4 system has been carried out through solid state reaction tech-nique. From the Powder XRD patterns, it is found that the compounds are formed in single phase and crystallizes in orthorhombic structure. The variation in lattice parameters with decreasing nature of volume of the prepared com-pounds confirms the incorporation of lower atomic radii Strontium in neodymium site. Surface morphology and ele-mental composition studies are also carried out to know the nature of the compounds and effect of Strontium substitu-tion in nd2CuO4 system. The paramagnetic nature of all the prepared compounds has been identified through magnetization studies and the results are correlated with the electron spin resonance studies by the way of variation in resonance field and broad peak width. Increasing order of dielectric constant on higher doping concentration of Strontium and the least value of dielectric loss at higher frequencies confirms the improved surface transport properties of the prepared compounds.

关键词： Ln2CuO4 Structural Analysis Powder XRD Dielectric Studies Magnetization ESR Analysis