• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.613-618
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• 2013

The quality characteristics of brown rice polished with grains of four rice varieties (Hwaseonchal, Baegjinju, Ilpum and Goami) were examined. For the physical properties of native and fried brown rice starches, the gelatinization temperatures and enthalpies (determined with differential scanning calorimetry) of brown rice starches decreased with increasing amylose content. The pasting viscosities of native brown rice starches in distilled water were higher than those in $HgCl_2$ solution (as an ${\alpha}$-amylase inhibitor). The highest viscosity of gelatinized starch was observed for the starch of Ilpum rice variety relative to other varieties. Cystal packing arrangement of brown rice starches subjected to deep-fat frying converted A-type (typically observed for cereal starches) into V-type (formed by retrogradation and recrystllization of amylose molecules).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.19-26
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• 2005

We have studied the relationship between static mode behavior and dynamic characteristics of multiple transverse-mode VCSELs by measuring the modal L-I and I-V characteristics. Dependence of the resonance frequencies of RIN (relative intensity noise) spectra on the injection current can be understood by modal L-I characteristics and mode-coupling effects. Each transverse mode behaves as an independent diode laser with the different threshold current in large active-area VCSELs, and the multiple-step turn-on is observed when step-current input is applied. This multiple-step turn-on is a result of different turn-on delay times of the transverse modes. Since the multiple-step turn-on increases the rise-time significantly, the wide active-area VCSELs are not suitable for high-speed optical transmitters unless the input current is adjusted for single transverse-mode operation.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.619-622
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• 2005

본 논문에서는 서로 다른 Si 두께 ($T_{Si}$ = 27, 50 nm) 를 갖는 SOI (Silicon On Insulator) 기판 위에 다양한 두께의 Ni/Co를 순차적으로 증착한 후 Bulk-Si과의 비교를 통해 Silicide의 형성 특성에 대하여 분석하였다. 우선 급속 열처리 (RTP, Rapid Thermal Processing) 를 통하여 Silicide를 형성한 후 측정결과 Si두께에 따라 Silicide의 특성이 달라짐을 확인하였다. 두꺼운 두께의 Si-film을 갖는 SOI 기판을 사용한 경우 증착된 금속의 두께에 따라 Bulk-Si와 비슷한 면저항 특성을 보였으나, 얇은 두께의 Si-film을 갖는 SOI기판을 사용한 경우에는 제한된 Si의 공급으로 인한 Silicide의 비저항 증가로 인하여 증착된 금속의 두께에 따라 면저항이 감소하다가 다시 증가하는 'V' 자형 곡선을 나타내었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.484-484
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• 2009

반도체 소자가 차세대 초미세 공정 기술 도입의 가속화를 통해 고속화 및 고집적화 되어 감에 따라 나노 (nano) 크기의 회로 선폭 미세화를 극복하고자 최적의 CMP (chemical mechanical polishing) 공정이 요구되어지고 있다. 최근, 금속배선공정에서 높은 전도율과 재료의 값이 싸다는 이유로 Cu를 사용하였으나, 디바이스의 구조적 특성을 유지하기 위해 높은 압력으로 인한 새로운 다공성 막(low-k)의 파괴와, 디싱과 에로젼 현상으로 인한 문제점이 발생하게 되었다. 이러한 문제점을 해결 하고자 본 논문에서는 Cu의 ECMP 적용을 위해 LSV (Linear sweep voltammetry)법을 통하여 알칼리 성문인 $NaNO_3$ 전해액과 산성성분인 $HNO_3$ 전해액의 전압 활성화에 의한 active, passive, transient, trans-passive 영역을 I-V 특성 곡선을 통해 알아보았고, 알칼리와 산성 성분의 전해액이 Cu 표면에 미치는 영향을 SEM (Scanning electron microscopy), EDS (Energy Dispersive Spectroscopy), XRD(X-ray Diffraction)를 통하여 전기화학적 특성을 비교 분석하였다.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.34-43
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• 2007

A comparative study of the extraction behavior of vanadium and titanium in sulphate solutions using Cyanex272, PC88A and Alamine336 has been carried out. effect of pH in sulphate solutions, concentration of extractant and extraction isotherms has been studied. Solvent extraction separation studies of vanadium and titanium from the mixed solutions were also carried out in order to obtain a criterion for choosing the more effective extraction regent. From the experimental results, it was conformed that Alamine336 was good extractant to extraction of vanadium and separation from titanium from the mixed solutions.

• Journal of the Korean Electrochemical Society
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• v.18 no.2
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• pp.51-57
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• 2015

We report the effect of the impurities including water and bromide in the propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI) on the electrochemical performance of lithium ion batteries. The several kinds of PMPyr-TFSI electrolytes with different amount of impurities are applied as the electrolyte to the cell with the high potential electrode, $LiNi_{0.5}Mn_{1.5}O_4$ spinel. It is found that the impurities in the electrolytes cause the detrimental effect on the cell performance by tracing the cycleability, voltage profile and Coulombic efficiency. Especially, the polarization and Coulombic efficiency go to worse by both impurities of water and bromide, but the cycleability was not highly influenced by bromide impurity unlike the water impurity.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.575-581
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• 2012

The electrochemical oxygen demand (ECOD) is an additional sum parameter, which has not yet found the attention it deserves. It is defined as the oxygen equivalent of the charge consumed during an electrochemical oxidation of the solution. Only one company has yet developed an instrument to determine the ECOD. This instrument uses $PbO_2$-electrodes for the oxidation and has been successfully implemented in an automatic on-line monitor. A general problem of the ECOD determination is the high overpotential of electrochemical oxidations of most organic compounds at conventional electrodes. Here we present a new approach for the ECOD determination, which is based on the use of a solid composite electrodes with highly efficient electro-catalysts for the oxidation of a broad spectrum of different organic compounds. Lead dioxide as an anode material has found commercial application in processes such as the manufacture of sodium per chlorate and chromium regeneration where adsorbed hydroxyl radicals from the electro-oxidation of water are believed to serve as the oxidizing agent. The ECOD sensors based on the Au/$PbO_2$ electrode were operated at an optimized applied potential, +1.6 V vs. Ag/AgCl/sat. KCl, in 0.01 M $Na_2SO_4$ solution, and reduced the effect of interference ($Cl^-$ and $Fe^{2-}$) and an expended lifetime (more than 6 months). The ECOD sensors were installed in on-line auto-analyzers, and used to analyze real samples.

• Journal of Sensor Science and Technology
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• v.9 no.3
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• pp.213-223
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• 2000

It is necessary that radiation dose would be detect exactly generated from facility related to nuclear, space, radiotherapy center, etc. This paper is to use of the radiation-induced threshold voltage change as an accumulated radiation dose monitoring sensor. Commercial P Channel Power MOSFET(metal oxide field effect transistor) were tested in a Co-60 gamma irradiation facility to see their capabilities as a radiation dosimeter. We found that the transistors showed good linearity in their threshold voltage shift characteristics with radiation dose. The results demonstrate the potential use of commercial P Channel Power MOSFET as inexpensive radiation sensors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.513-518
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• 2015

Salinity gradient power (SGP) has attracted significant attention because of its high potential. In this study, we evaluate reverse electrodialysis (RED) with various compositions of available resources. The polarization curve (I-V characteristics) shows linear behavior, and therefore the power density curve has a parabolic shape. We measure the power density with varying compartment thicknesses and inlet flow rates. The gross power density increases with decreasing compartment thickness and increasing flow rate. The net power density, which is the gross power density minus the pumping power, has a maximum value at a compartment thickness of 0.2 mm and an inlet flow rate of 22.5 mL/min. The power density in RED is also evaluated with compositions of desalination brines, seawater, river water, wastewater, and brackish water. A maximum power density of $1.75W/m^2$ is obtained when brine discharged from forward osmosis (FO) and river water are used as the concentrated and the diluted solutions, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.31-31
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• 2009

PECVD를 이용하여 제조된 미세결정질 p-i-n 실리콘 박막 태양전지에서, p 층은 태양전지의 윈도우 역할 및 그 위에 증착될 i ${\mu}c-Si:H$ 층의 'seed'층 역할을 수행하기 때문에, p층의 구조적 및 전기적, 광학적 특성은 태양전지의 전체 성능에 큰 영향을 미칠 수 있다. 본 연구에서는 $SiH_4$ 농도를 변화시켜 각기 다른 결정 특성을 갖는 p ${\mu}c-Si:H$층을 제조하고 그 위에 i ${\mu}c-Si:H$ 층을 증착하여 p층의 결정 특성변화와 그에 따른 i ${\mu}c-Si:H$ 층 및 'superstrate' p-i-n 미세결정질 실리콘 박막 태양전지의 특성 변화를 조사하였다. P층의 경우, $SiH_4$ 농도가 증가함에 따라 결정분율 (Xc)이 감소하여 비정질화되었으며 그에 따라 dark conductivity가 감소하는 경향을 나타내었다. 각기 다른 결정분율을 가지는 p 'seed' 층 위에 증착된 태양전지는, p 'seed' 층의 결정분율이 증가함에 따라 개방전압, 곡선인자, 변환효율이 경향적으로 감소하였다. 이는 p 층 결정분율 변화에 따른 p/i 계면특성 저하 및 그 위에 증착되는 i ${\mu}c-Si:H$ 층의 결함밀도 증가 등에 따른 태양전지 특성 감소 때문인 것으로 판단되며, 이를 분석하기 위하여 i ${\mu}c-Si:H$ 층의 전기적, 구조적 특성 분석 및 태양전지의 dark I-V 특성 등을 분석하고자 한다.