• Title/Summary/Keyword: Skin Depth

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Analyse of characteristic of Eddy current sensor using Boundary Element Method (경계요소해석을 이용한 와전류 센서의 특성 해석)

  • Yoon, Man-Sik;Choi, Duck-Su;Yang, Gyu-Chang;Lee, Hyang-Beom;Park, Seung-Han
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.697-699
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    • 2002
  • In this paper, the characteristics analysis of the eddy current sensor by using boundary element method package is presented. For the boundary element analysis. Faraday, which is the commercial package of the integrated engineering software, is used. To observe the impedance characteristic of the eddy current senor with the sensor position and lift-off, the eddy current testing analysis is performed on the ferromagnetic plate with defect. Considering the skin depth of the ferromagnetic specimen, the 800(Hz) driving source is chosen. The result shows that electro motive force is reduced as the probe moves to near the defect and the lift-off of the probe increases.

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The Effects of Substrate, Metal-line, and Surface Material on the Performance of RFID Tag Antenna

  • Cho, Chi-Hyun;Choo, Ho-Sung;Park, Ik-Mo
    • Journal of electromagnetic engineering and science
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    • v.7 no.1
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    • pp.47-52
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    • 2007
  • We investigated the effects of substrate, metal-line, and surface material on the performance of radio frequency identification(RFID) tag antenna using a tag antenna with a meander line radiator and T-matching network. The results showed that readability of the tag antenna with a thin high-loss substrate could be increased so that it was similar to that of a low-loss substrate if the substrate was very thin. The readability of the tag antenna decreased significantly when the metal line was thinner than the skin depth. The readability of the tag also decreased drastically when the tag was attached to high-permittivity high-loss target objects.

Value Addition Span of Silkworm Cocoon - Time for Utility Optimization

  • Reddy, R. Manohar
    • International Journal of Industrial Entomology and Biomaterials
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    • v.17 no.1
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    • pp.109-113
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    • 2008
  • Realizing the scope of utilizing by-products of silk cocoons by applying appropriate methods is the immediate crave to optimize returns. The nutritive value of pupae suits for human diet, feed for poultry, carps, fish, rabbits, piggery and dogs. The pupal skin, fat, oil, cocoon palade have applications in oleo chemical, soap, glycerin, cosmetic, artificial fibres, membranes and n-triacontanol isolation. The pupal proteins Chitin, Shinki fibroin, Serrapeptidase, glucosamine are latent precursors of post surgical, anti-carcinogenic, anti-inflammative, anti-bacterial, anti-histaminic, gastric, hepatitis, pancreatitis, leukocytopenia, neurological, ophthalmic, blood pressure, cardiac and diabetic medicines and for preparation of vitamins A, E and K. The silk and its proteins sericin and fibroin are potentially used for wound healing, diabetes, impotence, sinusitis, arthritis, edema, cystitis, epididymitis, tissue regeneration, cancer, post-surgical trauma and used as anti-oxidatives, bio-adhesives, ultra violet screens and bio-active textiles. The waste cocoons can be used in making art crafts like garlands, carpets, overcoats, decoratives and greeting cards. The in-depth research towards utility optimization and make aware this reality to sericulturists, reelers, weavers, traders, entrepreneurs, policy makers etc., is the upright want of the today's Sericulture industry.

Characteristics calculation on radio frequency power transfer in a planar inductively coupled plasma source (평면형 유도결합 플라즈마 장치에서의 RF 전력 전달 특성 계산)

  • 이정순;정태훈
    • Journal of the Korean Vacuum Society
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    • v.8 no.3B
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    • pp.368-375
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    • 1999
  • The Maxwell equation and the transformer equivalent-circuit model are applied to a radio frequency planar inductively coupled plasma. The spatial distribution of the vector potential, the magnetic field, and the electric field are obtained analytically. As a result, the plasma current, the mutual inductance between the coil and the plasma, and the self inductance of plasma are found to increase with increasing skin depth. The spatial distribution of absorbed power has maximum where the antenna coil exists, and has a similar profile to that of the induced electric field. The power transfer efficiency is found to increase with increasing gas pressure before a saturation around p+ 20mTorr, while it shows an increase with the plasma density before a slight decrease around a density of $5\times10^{11}/\textrm{cm}^3$.

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Simulation Study of Solar Wind Interaction with Lunar Magnetic Fields

  • Choi, Cheong Rim;Dokgo, Kyunghwan;Woo, Chang Ho;Min, Kyoung Wook
    • Journal of Astronomy and Space Sciences
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    • v.37 no.1
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    • pp.35-42
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    • 2020
  • Particle-in-cell simulations were performed to understand the interaction of the solar wind with localized magnetic fields on the sunlit surface of the Moon. The results indicated a mini-magnetosphere was formed which had a thin magnetopause with the thickness of the electron skin depth. It was also found that the solar wind penetrated into the cavity of the magnetosphere intermittently rather than in a steady manner. The solar wind that moved around the magnetosphere was observed to hit the surface of the Moon, implying that it may be the cause of the lunar swirl formation on the surface.

A Numerical Study on Temperature Profiles of Steel Plates Heated by Induction Heater (강재의 유도가열 방법의 수치적 승온 해석)

  • Kim, Hyeong-Jin;Chung, Won-Cheol;Cho, Byoung-Soo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1412-1416
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    • 2003
  • Induction Heaters are commonly used in heating steel strip product, because it can rapidly and efficiently heat steel strip/bar. In this study, a inductive heating model is developed and the predictions are compared with measured temperatures. The temperatures are measured from POSCO thin-slab rolling facility (so called Minimill). Induction heater is installed between reduction unit and holding furnace This induction heater raise the temperature of steel bars from $930^{\circ}C$ to about $1100^{\circ}C$ which gives the required temperature for finishing mill process after holding period at holding furnace. Unlike other simple equation models, this model allows us to predict temperature profiles of sections of steel bars.

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Characteristics of Specific Absorption Rate (SAR) in Electromagnetic (EM) Dosimetry

  • Hwang, Sun-Tae;Choi, Kil-Oung
    • Journal of Radiation Protection and Research
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    • v.25 no.2
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    • pp.109-114
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    • 2000
  • The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

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Epilepsy Surgery of the Cerebral Paragonimiasis

  • Lee, Woo-Jong;Koh, Eun-Jeong;Choi, Ha-Young
    • Journal of Korean Neurosurgical Society
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    • v.39 no.2
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    • pp.114-119
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    • 2006
  • Objective : The authors investigate appropriate evaluation and surgical methods in treatment of the cerebral paragonimiasis accompanying epilepsy. Methods : Thirteen patients with the cerebral paragonimiasis accompanying epilepsy were included for this study. Preoperative evaluation methods included history taking, skin and serologic tests for Paragonimus westermani, neurologic examinations, computerized tomography, magnetic resonance imaging, amytal test, PET or SPECT, and video-EEG monitoring with depth and subdural grid electrodes. Seizure outcome was evaluated according to Engel's classification. Results : Surgical methods were temporal lobectomy including lesions in six, lesionectomy in five, and temporal lobectomy plus lesionectomy in two. Postoperative neurological complications were not noticed, and seizure outcomes were class I in 12 patients [92%], class II in one [8%]. Conclusion : In patients with a cerebral paragonimiasis accompanying epilepsy, further evaluation methods must be done to define the epileptogenic zone, and complete resection of the epileptogenic zone with different surgical methods should be performed for seizure control.

Numerical Analysis of Eddy Current Testing for Pipe with Axi-symmetric Defect According to Frequency Changes (주파수 변화에 따른 축대칭 관결함의 와전류탐상 수치해석)

  • Seo, Jang-Won;Lee, Hyang-Beom;Jeong, Tae-Eon
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.102-104
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    • 2001
  • This paper presents a numerical analysis of the eddy current testing for pipe with axi-symmetric defect according to frequency changes using the finite element method(FEM). The defects used in this analysis are inner and outer axi-symmetric type. In order to obtain the behaviors of the signals by changing the frequency, the defects with different depths are modeled and analyzed using FEM. It is important to choose proper frequency because of the effect of skin depth in eddy current testing. This paper describes signal characteristics of each defects as frequency is changed.

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Performance Evaluation of Low Frequency Magnetic Field Shielding by Eddy-Current (와전류에 의한 저주파 자기장 차폐 성능 평가)

  • Choi, Hak-Yun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.9
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    • pp.124-128
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    • 2010
  • In this paper, the shielding effectiveness of aluminum shielded room with using eddy-current is calculated and measured after fabricated. The size and thickness of shielded room are decided as $2.4{\times}2.4{\times}2.4[m^3]$ and 12[mm] after AC shielding characteristics by eddy-current of conductive materials is analyzed. To verify the shielding effectiveness, a rectangular helmholtz coil is fabricated to generate magnetic field of 1.37[${\mu}T$] and measured magnetic field inside shielding room for 0.01~10[Hz]. According to calculations and measurements, AC Shielding effectiveness by eddy-current in aluminum is very small for 0.01~2[Hz] and 5 times to 11 times for 5~10[Hz].