• Title/Summary/Keyword: Maxwell

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Vertical Distribution of Biogenic Elements and its Implication on Holocene Paleoclimatic Records in the Maxwell Bay of the South Shetland Islands, West Antarctica

  • Kim, Dong-Seon;Park, Byong-Kwon;Yoon, Ho-Il
    • Journal of the korean society of oceanography
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    • v.32 no.2
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    • pp.69-74
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    • 1997
  • Depth profiles of organic carbon (C), biogenic silica (Si), and inorganic phosphorus (P) in Maxwell bay sediments were determined to investigate paleoclimatic changes during Holocene. Organic C and biogenic Si contents generally show a down-core decrease trend, which appears to be mostly controlled by their vertical fluxes through productivity in the surface waters, but it is uncertain that inorganic P contents are directly influenced by productivity changes with time. Before 4000 yr B.p. marine productivity seemed to be almost zero because ice permanently covered the surface waters of the study area. As the climate started to become relatively warm at 4000 yr B.p., ice was sporadically melted in the surface waters and thereby marine productivity gradually increased until 1500 yr B.p. For the last 1500 year, marine productivity must be high enough to overcome the dilution by high terrigenous sedimentation, thus that period was the warmest during the last 6000 year.

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The Temperature and Organic Gas Properties of Quartz Crystal Coated with LB Films (LB막을 누적한 수정진동자의 온도 및 유기가스 반응특성)

  • Yu, Seung-Yeop;Kim, Gyeong-Hwan;Jin, Cheol-Nam;Park, Jae-Cheol;Gwon, Yeong-Su
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.7
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    • pp.508-513
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    • 1999
  • The response properties of quartz crystal coated with stearic acid LB films to organic gases were investigated by measuring the shift of resonant frequency. Stearic acid was used as a sensing material and deposited on the surface of quartz crystal using the Langmuir-Blodgett(LB) method. The effect of temperature on the quartz crystal coated with stearic acid LB films was also investigated by Scanning Maxwell-stress Microscopy(SMM). As a result, the sensitivity of the quartz crystal coated with LB films to organic gases is dependent on temperature, thickness of LB film and molecular weight of organic gas.

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$\pi$-A properties of phospholipid monolayers by Maxwell-displacement-current-measuring technique (변위전류법에 의한 지질 단분자막의 $\pi$-A특성)

  • 이경섭;전동규;권영수;국상훈
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.05a
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    • pp.120-123
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    • 1995
  • Maxwell-Displacement-Currnt-Measuring Technique(MDCM) is a simple system for displacement current measuring which consist with two electrodes to the electrometer, With this method, the displacement current flow only when the electric flux density change by the displacement of molecules or charge particles of membrance on the water surface. Thus, It is Possible to detect dynamic behavior of molecules of membrane without any electrical contact with molecule membrane. In this paper, We measure surface pressure, displacement current and dipole moment of phospholipid monolayers on the wafer surface with applied pressure by MDCM and We measured DTA(differential thermal analysis).

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Effects of Gas-surface Interaction Models on Spacecraft Aerodynamics

  • Khlopkov, Yuri Ivanovich;Chernyshev, Sergey Leonidovich;Myint, Zay Yar Myo;Khlopkov, Anton Yurievich
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.1
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    • pp.1-7
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    • 2016
  • The influence of boundary condition of the bodies with gas flows is one of the most important problems in high-altitude aerodynamics. In this paper presents the results of the calculation of aerodynamic characteristics of aerospace vehicle using Monte-Carlo method based on three different gas-surface interaction models - Maxwell model, Cercignani-Lampis-Lord (CLL) model and Lennard-Jones (LJ) potential. These models are very sensitive for force and moment coefficients of aerospace vehicle in the hypersonic free molecular flow. The models, method and results can be used for new generation aerospace vehicle design.

Electromechanical Simulation of Cellulose Based Biomimetic Electro-Active Paper (생체모방종이작동기(Electro-Active Paper)의 전기기계적인 구동 시뮬레이션)

  • Jang, Sang-Dong;Kim, Heung-Soo;Kim, Jae-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.73-76
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    • 2007
  • Electro-Active paper (EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, which result good correlation with each other.

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Analysis of SAR Distribution Characteristics in a Head Model using FDTD (FDTD를 이용한 인체 두부모델의 SAR 분포특성 해석)

  • Hong, Dong-Uk;Kim, Doo-Hyun;Kang, Dong-Kyu
    • Journal of the Korean Society of Safety
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    • v.19 no.2
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    • pp.34-40
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    • 2004
  • This paper presents an analysis of SAR(Specific Absorption Rate) distribution characteristics in a head model using FDTD(Finite Difference Time Domain). In this study human head was modelled in four elements-layered structure, consisting of skin, fat, skull and brain. To calculate the electromagnetic fields wihtin the head model, FDTD method was used. In the FDTD method, the electromagnetic wave is analyzed by solving a Maxwell's equations repeatedly. For the calculation, distance between power source and head model increased by 10[m]. Power density and incident electric field intensity were calculated. Based on the incident electric field, the program which calaculated internal electric fields intensity and SAR calculation of the head model were developed. The results of developed program using FDTD were compared with those of a commericial programs, which showed the availability and usefulness of the suggested scheme in this paper.

The Study of the Electroconductive Liquids Flow in a Conduction Magnetohydrodynamic Pump

  • Naceur, Sonia;Kadid, Fatima Zohra;Abdessemed, Rachid
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.5
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    • pp.252-256
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    • 2016
  • This paper deals the study of a linear MHD pump solution used to eliminate and to avoid the dangers of the mercury appearing through pollution and contamination. The formulation of the magnetohydrodynamic phenomena is derived from Maxwell and Navier-Stokes equations are solved using the finite volume method. Simulation results highlight the performance of the pump such as the electromagnetic force, the velocity, and the pressure, the application of Ansys-Fluent software validation these results.

Electromagnetic Properties of Ring -Shaped Electrodeless Fluorescent Lamps for Ferrite Core (페라이트를 이용한 환형 무전극 램프의 전자계 특성)

  • Jo, Ju-Ung;Lee, Seong-Jin;Choi, Yong-Sung;Kim, Yong-Kab;Park, Dae-Hee
    • Proceedings of the KIEE Conference
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    • 2003.10a
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    • pp.249-251
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    • 2003
  • The ring-shaped electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. Therefore, the line time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250[kHz] and some specific conditions.

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Hydrogen Separation by Compact-type Silica Membrane Process (컴팩트 타입 실리카막 공정을 이용한 수소 분리)

  • Moon, Jong-Ho;Bae, Ji-Han;Lee, Sang-Jin;Chung, Jong-Tae;Lee, Chang-Ha
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.336-339
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    • 2006
  • With the steady depletion off fossil fuel reserves, hydrogen based energy sources become increasingly attractive. Therefore hydrogen production or separation technologies, such as Bas separation membrane based on adsorption technology, have received enormous attention in the industrial and academic fields. In this study, the transport mechanisms of the MTES (methyltriethoxysilane) templating silica/a-alumina composite membrane were evaluated by using unary, binary and quaternary hydrogen gas mixtures permeation experiments at unsteady- and steady-states. Since the permeation flux in the MTES membrane, through the experimental and theoretical study, was affected by molecular sieving effects as well as surface diffusion properties, the kinetic and equilibrium separation should be considered simultaneously in the membrane according to molecular properties. In order to depict the transient multi-component permeation on the templating silica membrane, the GMS (generalized Maxwell-Stefan) and DGM (dust Bas model) were adapted to unsteady-state material balance

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Characteristics of Ultrathin Film Prepared through Nano-Sized Langmuir Blodgett Monolayer of Functionalized Polyimide

  • Park, Keun-Ho;Lee, Soo
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.2
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    • pp.224-231
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    • 2009
  • Techniques measuring Maxwell displacement current (MDC) and LB films surface measuring technique have been applied to the study of monolayers of polyamic acid containing azobenzene. MDCs was generated from monolayers on the water surface by monolayer compression and expansion. It was generated when the area per molecule was about $103{\AA}^2\;and\;78{\AA}^2$ just before the initial rise of the surface pressure during the 1st and 2nd mixed monolayer compressions cycle, respectively. It was the maximum of MDCs appeared at the molecular area just before the initial rise of surface pressure in compression cycles, and we have found that the increase of aggregations causes the noticeable increase of the surface roughness.