• Journal of the Korean Professional Engineers Association
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• v.17 no.3
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• pp.22-31
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• 1984

Sardine ant mackerel so called dark muscled fish have been underutilized due to the disadvantages in bloody meat color, high content of fat, and postmortem instability of protein. Recent efforts were made to overcome these defects and develope new types of product such as texturized protein concentrates and dark muscle eliminated minced fish. Approach of this study is based on the rapicl dehydration of foamed fish-starch paste by dielectric heating. In process comminuted sardine meat was washed more than three times by soaking and decanting in chilled water and finally centrifuged. The meat was ground in a stone mortar added with adequate amounts of salt, foaming agent, and other ingredients for aid to elasticity and foam stability. The ground meat paste was extruded in finger shape and heated in a microwave oven to give foamed, expanded, and porous solid structure by dehydration. Dielectric constant ($\varepsilon$′) and dielectric loss ($\varepsilon$") vcalues of sardine meat paste were influenced by wavelength and moisture level. Those values at 100KHz and 15MHz were ranged 2.25∼9.86 ; 2.22∼4.18 for $\varepsilon$′ and 0.24∼19.24 ; 0.16∼1.25 for $\varepsilon$", respectively, at the moisture levels of 4.2∼13.8％. For a formula for fish-starch paste preparation, addition of 20∼30% starch (potato starch) to the weight of fish meat, 2∼4% salt, and 5∼10% soybean protein was adequate to yield 4∼5 folds of expansion in volume when heated. Addition of egg yolk was of benefit to micronize foam size and better crispness. In order to provide better foaming and dehydration, addition of 0.2∼0.5% sodium bicarbonate foaming agent, was proper to result in foam size of 0.5∼0.7mm and foam density of 200∼400/$\textrm{cm}^2$ which gave a good crispness.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.9
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• pp.456-465
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• 2001

In this paper, breakdown voltages in $SF_6-N_2$ mixtures were experimentally investigated to understand characteristics of dielectric strength and physical phenomena in nonuniform field disturbed by a needle shape protrusion. The test voltages are the lightning impulse$(\pm1.2/44 \mus)$ and the damped oscillatory impulse$(\pm400 ns / 0.83 MHz)$ voltages which can be occurred by the operation of disconnecting switches in gas-insulated switchgears(GIS). The effects of the polarity and wave shape of the test voltages, and the gas pressure on the V-t characteristics were in detail examined. The V-t characteristic curves were measured in different two ways : (1) one is the method by taking the maximum voltage recorded at or prior to breakdown against the time to breakdown, that is, the Procedures recommended in IEC 60060-1, (2) the other is the method by taking the voltage at the instant of chopping against the time to breakdown. As a result, the V-t characteristics of $SF_6-N_2$ mixtures in nonuniform electric field were significantly affected by the polarity and wave shape of the applied voltages. The positive breakdown voltages resulted in lower breakdown voltages in the time ranges considered, and the V-t curves for the negative oscillatory impulse voltage were extended over the longer time range. For the lightning impulse voltages, the V-t curves obtained by IEC Pub. 60060-1 were nearly same with the V-t curves obtained by the voltage at the instant of chopping against the time to breakdown. It is clear that the actual breakdown voltages were much lower than the maximum voltages appearing at or prior to breakdown because of the displacement current produced as a result of the dV/dt during the oscillatory transient voltage app1ication. The scattering of the negative actual breakdown voltages was much larger than that of the positive.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.59-63
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• 2016

The superconducting NMR magnets have used cryogen such as liquid helium for their cooling. The conduction cooling method using cryocoolers, however, makes the cryogenic cooling system for NMR magnets more compact and user-friendly than the cryogen cooling method. This paper describes the thermal and structural analysis of a cryogenic conduction cooling system for a 400 MHz HTS NMR magnet, focusing on the magnet assembly. The highly thermo-conductive cooling plates between HTS double pancake coils are used to transfer the heat generated in coils, namely Joule heating at lap splice joints, to thermal link blocks and finally the cryocooler. The conduction cooling structure of the HTS magnet assembly preliminarily designed is verified by thermal and structural analysis. The orthotropic thermal properties of the HTS coil, thermal contact resistance and radiation heat load are considered in the thermal analysis. The thermal analysis confirms the uniform temperature distribution for the present thermal design of the NMR magnet within 0.2 K. The mechanical stress and the displacement by the electromagnetic force and the thermal contraction are checked to verify structural stability. The structural analysis indicates that the mechanical stress on each component of the magnet is less than its material yield strength and the displacement is acceptable in comparison with the magnet dimension.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.6
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• pp.439-444
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• 2012

For the application of photo-detector as active layer, we have studied how to deposit SiGe thin film using an independent Si target and Ge target, respectively. Both targets were synthesized by purity of 99.999%. Plasma generators were generated by radio frequency (rf, 13.56 MHz) and direct current (dc) power. When Ge and Si targets were sputtered by dc and rf power, respectively, we could observe the growth of highly crystalline Ge thin film at the temperature of $400^{\circ}C$ from the result of raman spectroscopy and X-ray diffraction method. However, SiGe thin film did not deposit above method. Inversely, we changed target position like that Ge and Si targets were sputtered by rf and dc power, respectively. Although Ge crystalline growth without Si target sputtering deteriorated considerably, the growth of SiGe thin film was observed with increase of Si dc power. SiGe thin film was evaluated as microcrystalline phase which included (111) and (220) plane by X-ray diffraction method.

• The KIPS Transactions:PartA
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• v.13A no.5 s.102
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• pp.387-398
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• 2006

In this paper, we propose a new page allocation scheme for flash memory file system. The proposed scheme allocates pages by exploiting the concept of Purity, which is defined as the fraction of blocks where valid Pages and invalid Pages are coexisted. The Pity determines the cost of block cleaning, that is, the portion of pages to be copied and blocks to be erased for block cleaning. To enhance the purity, the scheme classifies hot-modified data and cold-modified data and allocates them into different blocks. The hot/cold classification is based on both static properties such as attribute of data and dynamic properties such as the frequency of modifications. We have implemented the proposed scheme in YAFFS and evaluated its performance on the embedded board equipped with 400MHz XScale CPU, 64MB SDRAM, and 64MB NAND flash memory. Performance measurements have shown that the proposed scheme can reduce block cleaning time by up to 15.4 seconds with an average of 7.8 seconds compared to the typical YAFFS. Also, the enhancement becomes bigger as the utilization of flash memory increases.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.285-286
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• 1998

Virtual Brain-endoscopy is an effective method to detect lesion in brain. Brain is the most part of the human and is not easy part to operate so that reconstructing in 3D may be very helpful to doctors. In this paper, it is suggested that to increase the reliability, method of matching 3D object with the 2D CT slice. 3D Brain-endoscopy is reconstructed with 35 slices of 2D CT images. There is a plate in 3D brain-endoscopy so as to drag upward or downward to match the relevant 2D CT image. Relevant CT image guides the user to recognize the exact part he or she is investigating. VRML Script is used to make the change in images and PlaneSensor node is used to transmit the y coordinate value with the CT image. The result is test on the PC which has the following spec. 400MHz Clock-speed, 512MB ram, and FireGL 3000 3D accelerator is set up. The VRML file size is 3.83MB. There was no delay in controlling the 3D world and no collision in changing the CT images. This brain-endoscopy can be also put to practical use on medical education through internet.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.507-507
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• 2012

컷오프 진단법은 두 개의 탐침 형태로 제작된 마이크로 웨이브 진단법으로, 간단한 수식을 통해 전자밀도, 전자온도 등을 측정할 수 있다. 컷오프 탐침은 방사 안테나, 측정 안테나와 네트워크 분석기로 구성되어 있다. 네트워크 분석기는 두 안테나 사이의 플라즈마 투과 스펙트럼을 만드는데 쓰이며, 스펙트럼 분석을 통해 플라즈마 변수들을 측정할 수 있다. 이 진단법은 장치나 분석방법이 매우 간단한 장점을 지니며, 약 1 mW 정도의 적은 파워를 사용하여 플라즈마 상태를 거의 변화시키지 않는 측정이 가능하다. 또한 CF4와 같은 공정 가스를 이용한 플라즈마에서도 사용이 가능하다. 그러나 컷오프 진단법을 사용한 측정은 다른 종류의 진단법과 마찬가지로, 약 1초 정도의 긴 시간을 필요로 하는 단점이 있어, 펄스 플라즈마나 토카막과 같이 빠르게 변하는 플라즈마를 측정하기에는 무리가 있다. 컷오프 탐침의 시간 분해능을 향상시키고자, 최근에 푸리에 컷오프 탐침(FCP)이 개발되었다. 펄스 형태의 단일신호를 플라즈마를 투과하기 전후로 비교하면 투과 스펙트럼 및 플라즈마 변수들을 얻을 수 있으며, 측정시간을 약 15 ns 정도로 줄일 수 있었다. 이 방법의 신뢰도 및 성능은 이미 CW 플라즈마와 펄스 플라즈마에서 확인되었다. 본 연구에서는 FCP의 초고속 측정의 장점을 이용해서 13.56 MHz의 CCP 및 400 kHz의 CCP에서 RF 위상에 따라 변하는 플라즈마를 측정하였으며, 이에 따라 RF CCP에서의 전자의 동역학 분석을 할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.95-98
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• 2002

전력선 통신 blocking filter용 자심 재료를 개발하기 위해서 MnO 24 mol%, ZnO 25 mol% and $Fe_{2}O_{3}$ 51 mol% 의 기본조성에 $MoO_{3}$, $SiO_{2}$, CaO를 첨가하여 $1350^{\circ}C$에서 대기압 상수 A를 7.8롤 고정하고 소결하여 미세구조를 제어하였으며 기본 조성에 $MoO_{3}$ 400 ppm, $SiO_{2}$ 100 ppm and CaO 200 ppm을 첨가한 경우 평균 입경 $25{\mu}m$ 의 균일한 결정립으로 구성된 미세구조를 얻었고 기공의 감소에 의한 치밀화로 $4.98g/cm^{2}$의 고밀도화가 이루어 졌다. 또한 소결체의 균일한 미세구조와 고밀도화로 인해서 8221(${25^{\circ}C}$, 1 KHz) 의 가장 높은 투자율 특성을 나타냈다. 시편의 온도가 증가함에 따라 투자율이 증가되어 ${110^{\circ}C}$에서 13904의 거대 투자융이 측정되었고, 코일의 인가주파수가 1 KHz에서 1 MHz까지 증가됨에 따라 최고 ${102^{\circ}C}$까지 시편 온도가 상승하였다. 가장 높은 투자율 특성을 나타낸 ferrite 코어를 사용하여 단상 및 3상용 블로킹 필터의 감쇄율을 측정한 결과 현재 국내의 전력선 통신용 주파수 대역으로 규정되어 있는 10 KHz ~ 450 KHz 대역에서 각각 -46.46 dB와 -73.9 dB의 최고 값을 얻었다.

• Korean Journal of Agricultural Science
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• v.35 no.1
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• pp.11-17
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• 2008

This study was conducted to isolate polyacetylenes from the Acanthopanax senticosus and to identify the chemical structure of the polyacetylenes by UV, IR, $^1H$-NMR and $^{13}C$-NMR. One of the liposoluble materials was extracted with petroleum ether. Polyacetylene compounds were collected through solvent fractionation at silica gel column chromatograph. The HPLC was used for the semi-preparative separation IR spectra of fraction 5 showed triple bonds at $2256cm^{-1}$ and double bond at $1654cm^{-1}$, respectively, $^1H$-NMR spectra of Fraction 5 showed the double bond at 5.35-5.48 ppm. Triple bond at 64.0. 71.2, 74.2, 80.2 ppm and double bond at 121.89, 133.0 ppm were observed in the $^{13}C$-NMR spectra.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1806-1808
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• 2000

MHz영역에서 사용 가능한 Fe계 연자성 재료를 초미세 결정립으로 제조하기 위해 $Fe_{93}Zr_{3}B_4$ 박막을 기본조성으로 하여 Fe와 비고용이며 약반자성인 Ag 원소를 0, 3, 4, 5, 6, 10 at.% 첨가시킨 $Fe_{93-x}Zr_{3}B_{4}Ag_{x}$ 박막을 DC 마그네트론 스퍼터링법으로 제조하였다. 그리고, 300-600$^{\circ}C$ 온도 범위에서 1시간동안 열처리한 후 강제공냉법으로 냉각한 후 XRD를 이용하여 열처리 온도 및 Ag 첨가량에 따른 결정상 동정을 조사하였다. Ag가 첨가되지 않은 $Fe_{93}Zr_{3}B_4$ 박막의 경우 $\alpha$-Fe의 (110) 피크만 관찰되었다. Ag가 첨가된 경우에는, Ag의 양이 증가함에 따라 $\alpha$-Fe 결정상의 형성이 억제되고, 비정질형태의 broad한 ${\alpha}-Fe_{(110)}$ 피크와 Ag피크가 관찰되었다. Ag가 첨가된 As-deposited 시편을 열처리 할 경우 박막의 비정질화로 주 peak인 $\alpha$-Fe 피크의 강도가 현저히 낮아지고 상대적으로 Ag peak가 두드러졌다. Ag의 양이 3a/o인 경우는 열처리온도 400$^{\circ}C$이상에서 박막의 결정화로 $\alpha$-Fe Peak가 나타나고 상대적으로 Ag 구성원소의 피크의 강도는 현저하게 낮아졌다 또한. Ag의 양 증가할수록 As-deposited 박막 내에 Ag 구성원소외 피크의 강도는 증가하여 $\alpha$-Fe와 Ag가 서로 비고용 상태로 서로 혼재되어 있었다.