• Title/Summary/Keyword: High sensitivity

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A Hybrid ON/OFF Method for Fast Solution of Electromagnetic Inverse Problems Based on Topological Sensitivity

  • Kim, Dong-Hun;Byun, Jin-Kyu
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.240-245
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    • 2011
  • A new hybrid ON/OFF method is presented for the fast solution of electromagnetic inverse problems in high frequency domains. The proposed method utilizes both topological sensitivity (TS) and material sensitivity (MS) to update material properties in unit design cells. MS provides smooth design space and stable convergence, while TS enables sudden changes of material distribution when MS slows down. This combination of two sensitivities enables a reduction in total computation time. The TS and MS analyses are based on a variational approach and an adjoint variable method (AVM), which permits direct calculation of both sensitivity values from field solutions of the primary and adjoint systems. Investigation of the formulations of TS and MS reveals that they have similar forms, and implementation of the hybrid ON/OFF method that uses both sensitivities can be achieved by one optimization module. The proposed method is applied to dielectric material reconstruction problems, and the results show the feasibility and effectiveness of the method.

Sensitivity Changes of Auxin Transport System in Maize Coleoptile Segments

  • 윤인선
    • Journal of Plant Biology
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    • v.36 no.1
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    • pp.59-66
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    • 1993
  • In maize coleoptile segments where auxin transport capacity decreases with time following excision, susceptability of the tissue to transport inhibitors such as N-1-naphthylphthalamic acid (NPA), 3,4,5-triiodobenzoic acid (TIBA) or high concentrations of IAA was found to be rather increased. A time-dependent increase in the sensitivity to NPA can be postulated since the dose-response curve for NPA was shifted in the‘aged’tissue to the left (i.e. lower concentration). Preincubation of the tissue at a low temperature abolished the time-dependent sensitivity change, suggesting that cellular metabolism could be involved. The NPA-sensitive state was also brought about by calcium depletion of the tissue, which can be partially reversed by addition of calcium. Presence of exogenous IAA in the preincubation medium kept the auxin transport system from decay, implicating auxin as an endogenous controlling factor. Results of our experiments indicate a reversible, time-dependent changes of auxin transport system in which transport capacity and sensitivity to NPA are tightly coupled. Changes in the sensitivity to NPA were also seen in auxin action as well.

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GIANT MAGNETORESISTANCE AND LOW MAGNETOSTRICTION IN DISCONTINUOUS NiFe/Ag MULTILAYER THIN FILMS

  • Kim, Young-Keun
    • Journal of the Korean Magnetics Society
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    • v.6 no.3
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    • pp.189-193
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    • 1996
  • Magnetoresistance field sensitivity and magnetostriction were measured as a function of annealing temperature for NiFe/Ag multilayer systems displaying giant magnetoresistance. Key multilayer configurations such as number of NiFe/Ag bilayers and Ag spacer thickness were varied. A high giant magnetoresistance ratio up to 5% with zero magnetostriction and high magnetoresistance field sensitivity was possible to achieve simultaneously with optimal sample geometry and annealing condition.

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A Study on the Frequency Response Characteristics of High Response Flow Control Servo Valve (고 응답 유량제어 서보밸브의 주파수 응답특성에 관한 연구)

  • 서종수;신유식;지명국;전영흥;정효민;정한식
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.6
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    • pp.480-488
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    • 2003
  • The purpose of this research Is to derive the principal design parameters governing the dynamic characteristics of the high response flow control servo valve. For this purpose, a numerical modeling of the servo valve system and a parameter sensitivity analysis to a frequency response characteristics was peformed. As a result of these analysis, a basis for improvement of a dynamic characteristics of servo valve was arranged.

MURA Detection Method using a Slit-Beam-Profile Ellipsometer

  • Murai, Hideyuki;Ekawa, Koichi;Takashima, Jun;Naito, Hitoshi;Nakatsuka, Nobuo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1465-1468
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    • 2006
  • We developed a new ellipsometer for MURA detection. This ellipsometer can measure MURA along the slit line on the sample with high sensitivity, because this ellipsometer irradiates a slit beam onto the sample but can reject the reflected light from the back surface of the substrate. This ellipsometer is suitable for measuring MURA of the surface of sample with high sensitivity.

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A new theoretical model for the dynamical analysis of Nano-Bio-Structures

  • Di Sia, Paolo
    • Advances in nano research
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    • v.1 no.1
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    • pp.29-34
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    • 2013
  • The conversion of mechanical energy into electrical energy at nanoscale using piezoelectric nanowire arrays has been in detail shown by deflection of nanowires. Recently it has performed an analytical model, both at classical and at quantum level, for describing the most important quantities concerning transport phenomena; the model predicts interesting peculiarities, as high initial charge diffusion in nanodevices constituting by nanowires and permits also in particular to deduce interesting informations about the devices sensitivity, focusing on the correlation between sensitivity and high initial diffusivity of these materials at nanometric level.

Fiber-Optic Temperature Sensor Based on Single Mode Fused Fiber Coupler

  • Kim, Kwang-Taek;Park, Kiu-Ha
    • Journal of the Optical Society of Korea
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    • v.12 no.3
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    • pp.152-156
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    • 2008
  • This paper reports a fiber-optic temperature sensor using a single mode fused fiber coupler incorporating a thermo-optic external medium. The spectral transmission was altered by changing the refractive index of the external thermo-optic medium. A theoretical and experimental investigation was carried out with the aim of achieving high sensitivity. The measured sensitivity for the environmental temperature was as high as -1.5 $nm/^{\circ}C$.

Formation and humidity-sensing properties of porous silicon oxide films by the electrochemical treatment (전기화학적 처리에 의한 다공질 실리콘 산화막의 형성과 감습 특성)

  • 최복길;민남기;류지호;성영권
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.1
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    • pp.93-99
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    • 1996
  • The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

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Comparison Study of Sensitivity Factors of Elements in Glow Discharge- & Inductively Coupled Plasma- Mass Spectrometry

  • Kim, Young-Sang;Plotnikov, M.;Hoffmann, Volker
    • Bulletin of the Korean Chemical Society
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    • v.26 no.12
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    • pp.1991-1995
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    • 2005
  • Sensitivity factors of elements by a glow discharge mass spectrometry (GD-MS) were intensively investigated and compared with a laser ablation inductively coupled plasma-mass spectrometry (ICP-MS). In case of copper matrix, the sensitivity factor by GD-MS generally decreases with the increase of the mass number of element. The details are a little different between each data measured by Faraday and multiplier detectors. The factor by a multiplier detector drastically decreases with the mass increase in the region of low mass as in Faraday detector’s case, but slowly in the high mass region. On the contrast, the sensitivity factor of solution standard by a conventional ICP-MS slowly increases with the increase of elemental mass number even though there are some exceptions such as gold and also the sensitivity factor by a laser ablation ICP MS generally increases with mass number of element in the specimen of glass type. In case of steel matrix, any definite trends could not be shown in the relationship between the GD-MS’s sensitivity factor and elemental mass.