• Journal of the Korean Ceramic Society
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• v.32 no.11
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• pp.1292-1300
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• 1995

The ionic conductivity of NASICON solid electrolytes was simulated by using Monte Carlo Method (MCM). There were included two conduction paths: (1) Na1-Na2 and (2) Na1-Na2 including Na2-Na2. We assumed that mid-Na ions provde an additional driving force for Na mobile ions due to the interionic repulsion between Na1 and Na2 ions. The inflection point of vacancy availability factor, V has been shown at nearby x=2, the maximum mid-Na ions. The inflection point of vacancy availability factor, V has been shown at nearby x=2, the maximum mid-Na sites are occupied. The effective jump frequency factor, V has been shown at nearby x=2, the maximum mid-Na sites are occupied. The effective jump frequency factor, W increased rapidly with the composition at low temperature, but decreased at high temperature region. On Na1-Na2 conduction path, the minimum of charge correlation factor, fc and the maximum of $\sigma$T were appeared at x=2.0. this indicated that mid-Na ions affect on the high ionic conductivity behavior. At the whole range of NASICON composition, 1n $\sigma$T vs. 1/T* plots have been shown Arrhenius behavior but 1n (VWFc) vs. 1/T* have been shown the Arrhenius type tendency at x=2, which mid-Na is being the maximum. The results of MCM agreed with the experimental one when the chosen saddle point value was 6$\varepsilon$ : 3$\varepsilon$. Here the calculated characteristic parameter of materials, K and the phase transition temperature were -4.001$\times$103 and 178$^{\circ}C$ (1/T*=1.92, 1000/T=2.22), respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.73-73
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• 2008

일반적으로 청색 및 자외선 발광다이오드, 레이저 다이오드, UV 감지기 (detector)소자 등의 기술적인 중요성은 ZnO를 기반으로 하는 산화물 반도체와 함께 와이드 밴드갭 반도체 연구가 활발히 진행되고 있다. ZnO의 경우 밴드갭 엔지니어링을 위해 일반적으로 Cd과 Mg을 사용하고 있으며 특히, ZnO에 Mg을 첨가하여 MgZnO 화합물을 첨가할 경우 밴드갭을 3.3eV~7.8eV까지 증가 시킬 수 있고, MgZnO/ZnO 초격자 구조를 이용할 경우 자유 엑시톤 결합에너지를 100meV 이상까지 증가시킬 수 있는 장점을 가지고 있다. 그러나 MgO는 결정구조가 rocksalt 구조를 가지는 입방정 구조이기 때문에 Hexagonal 구조를 가진 ZnO에 첨가될 경우 고용도에 큰 제한을 가지게 된다. 이와 같은 문제점으로 인하여 밴드갭 엔지니어링 기술은 여전히 해결되지 않은 문제점으로 남아 있다. 본 실험에서는 RF 마그네트론 스퍼터링 방법으로 사파이어 기판위에 MgZnO/ZnO 박막을 co-sputtering 시켰다. Targer은 ZnO(99.999%) 와 MgO (99.999%) target을 사용하였고, 스퍼터링 가스는 아르곤과 산소가스를 2:1 비율로 혼합시켜 성장하였다. MgZnO 박막을 성장하기 전 ZnO 층을 ~500 두께로 성장 시켰다. RF-power는 ZnO target을 고정 시키고, MgO targe power를 변화시켜 Mg 농도를 조절 하였다. 실험 결과 MgO target power 가 증가 할수록 반치폭이 증가하고, c-plane을 따라 격자 상수가 감소하는 것을 확인 할 수 있고, UV emission peak intensity가 감소며 단파장쪽으로 blue shift 하고, activation energy 가 증가하는 것을 관찰 할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.98.1-98.1
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• 2010

본 실험에서는 $CuInSe_2$ 3원물질을 화학량론적 조성비가 되도록 박막을 제조하기 위해 각 단위원소를 원자비에 맞춰 전자선가열 진공증착기를 사용하여 Cu, In, Se 순으로 증착하였다. $90^{\circ}C$이하의 온도에서 $CuIn_2$, In상이 주를 이루며, $100^{\circ}C$이상에서는 $Cu_{11}In_9$상이 나타나기 시작하고 In상이 증가하였다. $10^{-3}torr$이상의 진공석영관에서 열처리와 동시에 Selenization을 통해 제작된 $CuInSe_2$박막은 열처리온도 $250^{\circ}C$에서는 CuxSe, CuSe등의 2차상들이 나타나다가 $450^{\circ}C$이상의 고온에서 $CuInSe_2$ 단일상을 형성하였다. 이로부터 진공중에서 반응을 시켰을 때, 더 낮은 온도에서 반응이 일어나고 열역학적으로 보다 안정한 소수의 화합물들이 쉽게 형성됨을 확인할 수 있었다. 특히 $250^{\circ}C$에서는 Sphalerite 구조를 가지다가 $350^{\circ}C$이상의 온도에서 Selenization하였을 때 Chalcopyrite 구조를 가졌다. 박막이 두꺼워지면서 결정립의 크기가 커지고 응력이 작아지는 특성을 보였다. 에너지 밴드갭은($E_g$)은 Cu/In 성분비율이 클수록 작은값을 보였으며, 결절립크기가 증대되므로 결국 흡수계수가 낮아짐을 알 수 있다. 또한 두께가 증가할수록 전반적으로 흡수계수가 증가하였고 Cu/In의 성분비율이 0.97일 때 기초흡수파장은 1,169nm이고 에너지밴드갭은 1.06eV이었으며, 두께 $1.5{\mu}m$이상일 때 전반적으로 양호한 상태의 p-type $CuInSe_2$박막을 제작하였다.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.500-506
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• 2000

The effects of sodium stearoyl lactylate(SSL) on the thermal properties of wheat starch and amylopectin, and the crystallinity properties of amylopectin were investigated using differential scanning calorimetry(DSC) and X-ray diffractometer. On the rescan(second heating), amylopectin produced the featureless thermogram shown at the second heating, and SSL alone melted at $40{\sim}55^{\circ}C$, while the mixture of amylopectin containing 8% water and SSL(10:1), presenting the evidence of AP-SSL complex, showed differentiate melting temperature(other crystallinity) from SSL alone. Also, the melting enthalpy of AP and SSL mixture by subsequent heating and cooling were continuously increased. Further, the mixtures of wheat starch: SSL (5:1, w/w) and amylopectin: SSL(5:1, w/w), indicated AP-SSL complex, showed the reversible melting peak at temperature range of $60{\sim}70^{\circ}C$ together with melting peak of SSL observed at temperature range of $40{\sim}55^{\circ}C$. AP-SSL complex in the X-ray diffraction, compared V-form of amylose-lipid complex, exhibited characteristic peaks($2{\theta}$, 5.57, 20.903, 23.227). The gelatinization enthalpy value of wheat starch in the presence of SSL, observed at temperature range of $50{\sim}70^{\circ}C$, was decreased at total water content 60%, whearas had no significant effect at total water content 40, 50%, and also, SSL increased melting enthalpy of amylose-lipid complex. The extent of AP and wheat starch retrogradation wasreduced significantly by SSL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.440-443
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• 2002

Present1y the X-Ray diagnosis system is a real condition that is changing by digital ways in it's existent analog ways. This digital radiation detector is divided by the direct method and the indirect method. The indirect method of applied voltage has special qualities that the resolution is low than direct method by diffusion effect that happens. The conversion process ( radiation${\rightarrow}$visible ray${\rightarrow}$electrical signal of two times, has shortcomings that the energy conversion efficiency of electrical signal is low. The direct method has shortcomings that need strong electric fie1d to detect electrical signal efficiently. This research achieved to develop digital detector of the Hybrid method that have form that mixes two ways to supplement shortcoming of direct. indirect method. A studied electrical characteristic by Iodine's Mixture ratio change is added to selenium in the detector which has a multi-layer structure (Oxybromide + a-Se). There are 8 kinds of Manufactured compositions to amorphous selenium Iodine each 30ppm, 100ppm, 200 ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm by a doped photoconductor through a vacuum thermal evaporation method. The phosphor layer is consisted of Oxybromide ($BrO_2$) which uses optical adhesives multi-layer structure. The manufactured compositions calculates and compares Net Charge and signal to noise ratio measuring Photocurrent about Darkcurrent and X-ray. When doped Iodine Mixture ratio is 500ppm to the multi-layer structure (Oxybromide + a-Se), applied voltage of $3V/{\mu}m$, leakage current of compositions $2.61nA/cm^2$ and net charge value by 764pC/$cm^2$/mR then the best result appeared.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.275-284
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• 2008

Purpose: We intended to evaluate myocardial oxygen consumption ($MVO_2)$ by applying recirculation correction and modified one-compartment model to have a reference range of $MVO_2$ in normal young population and to reveal the effect of recirculation on time-activity curve (TAC). Materials and Methods: In nine normal male volunteers with mean age of $26.3{\pm}4.0$, $MVO_2$ was estimated with 925 MBq (25mCi) of $^{11}C$-Acetate (Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, Korea) and PET/CT (Biograph 6, Siemens Medical Solution, Germany). Analysis software such as $MATLAB^{(R)}$ v7.1 (Mathworks, Inc., United States), $Excel^{(R)}$ 2007 (Microsoft, United States), and $SPSS^{(R)}$ v12.0 (Apache Software Foundation, United States) were used. Twenty three frames were of $12{\times}10$, $5{\times}60$, $3{\times}120$, $2{\times}300's$ duration, respectively. The modified one-compartmental model and the recirculation correction method were applied. Statistical analysis was performed by using Test of Normality, ANOVA and Post-Hoc (Scheffe's) analysis, and p-value less than 0.05 was considered as significant. Results: The normal reference ranges of $MVO_2$ were presented as $3.18-4.64\;{\times}\;10^{-4}\;ml/g/sec$, $1.91-3.94\;{\times}\;10^{-4}\;ml/g/sec$, $4.31-6.40\;{\times}\;10^{-4}\;ml/g/sec$, $2.84-4.53\;{\times}\;10^{-4}\;ml/g/sec$ and $3.42-5.00\;{\times}\;10^{-4}\;ml/g/sec$ in the septum, the inferior wall, the lateral wall, the anterior wall and the entire wall, respectively. In addition, it was noted that the dual exponentiality of the clearance curve is due to the recirculation effect and that the characteristic of the curve is essentially mono-exponential. Conclusion: $^{11}C$-Acetate is a radiotracer worthwhile to assess $MVO_2$. Re-circulated $^{11}C$ can influence TAC of $^{11}C$ in myocadia and so the recirculation correction must be considered when measuring $MVO_2$.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.236-243
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• 2009

Proton Engineering Frontier Project (PEFP) has supplied the metal ions to users by using an installed metal ion implanter of 120 keV. At present a feasibility study is being performed for a cobalt ion implantation. For a cobalt ion extraction we studied to sustain the high temperature($648^{\circ}C$) for metal ions vaporization from a cobalt chloride powder by using an alumina crucible in the ion source. The temperature condition of the crucible was satisfied with the plasma generation at the arc current of 120V and EHC power of 250W. The extracted beam current of $Co^+$ ions was dependent on the arc current in the plasma. The maximum beam current was $100{\mu}A$ at 0.18A of the arc current. The 3 peak currents of the extracted ions such as $Co^+$, $CoCl^+$ and $Cl^+$ were obtained by adjusting a mass analyzing magnet and the $Co^+$ ion beam peak current fraction as around 70% in the sum of the peak currents. The fluence of the implanted cobalt ions at the $10{\mu}A$ of the beam current and 90 minutes of the implantation time into an aluminum sample as measured around $1.74{\times}10^{17}#/cm^2$ by a quantitative analysis method of RBS (Rutherford Backscattering Spectrometry).

• Journal of Energy Engineering
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• v.27 no.4
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• pp.1-12
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• 2018

The code and standards related to fuel cells were analyzed to derive the SOFC(Solid Oxide Fuel Cell) stack safety performance evaluation items and evaluation methode. Safety performance evluation of the SOFC stack was tested by quoting derived test items. The stack used in the test is an anode-supported type 2 Cell stack (Active surface area : 220cm) manufactured by MICO Inc, and SOFC stack safety performance evaluation system used for the test is self-manufactured. We conducted a leakage test, current voltage characteristic test, rated output test, and power response characteristics test. In the safety performance evaluation test, the stack showed no gas leakage, the maximum output and rated output was recorded to 65.6 W(1.41 V, 46.5 A, $422mA/cm^2$), 62.3 W(1.57 V, 40 A, $363mA/cm^2$). In the power response characteristics test verified that the output is kept stable within two seconds. At the maximum load (40 A) and the minimum load (8 A), the output was recorded 62 W and 16W in $750^{\circ}C$. This study will contribute to the universalization and to provide much safe environment of operating the solid oxide fuel cell system.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.160-160
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• 2016

In this study, we applied the low temperature curing Ag paste to replace PVD System. The electrode formation of low temperature curing Ag paste for silicon Hetero-junction solar cells is important for improving device characteristics such as adhesion, contact resistance, fill factor and conversion efficiency. The low temperature curing Ag paste is composed various additives such as solvent, various organic materials, polymer, and binder. it depends on the curing temperature conditions. The adhesion of the low temperature curing Ag paste was decided by scratch test. The specific contact resistance was measured using the transmission line method. All of the Ag electrodes were experimented at various curing temperatures within the temperature range of $160^{\circ}C-240^{\circ}C$, at $20^{\circ}C$ intervals. The curing time was also changed by varying the conditions of 10-50min. In the optimum curing temperature $200^{\circ}C$ and for 20 min, the measured contact resistance is $19.61m{\Omega}cm^2$. Over temperature $240^{\circ}C$, confirmed bad contact characteristic. We obtained photovoltaic parameter of the industrial size such as Fill Factor (FF), current density (Jsc), open-circuit voltage (Voc) and convert efficiency of up to 76.2%, 38.1 mA/cm2, 646 mV and 18.3%, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.359-365
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• 2013

The high mobility group box 1 (HMGB1) protein is a multifunctional cytokine-like molecule that plays an important role in the pathogenesis of tumors. In this study, real-time polymerase chain reactions and Western blot assays indicated that HMGB1 transcriptional activity and protein level are increased in $Tax^+$-T cells (TaxP). To clarify the mechanisms, a series of HMGB1 deletion reporter plasmids (pHLuc1 to pHLuc6) were transfected into $Tax^-$-T cells (TaxN, Jurkat) and $Tax^+$-T cells (TaxP). We found that promoter activity in $Tax^+$-T cells to be higher than that in $Tax^-$-T cells, indicating a significant increase in pHLuc6. Bay11-7082 (NF-${\kappa}B$ inhibitor) treatment did not block the enhancing effect. Chromatin immunoprecipitation assays revealed that Tax was retained on a HMGB1 promoter fragment encompassing -1163 to -975. Bioinformatics analysis showed six characteristic cis-elements for CdxA, AP-1, AML-1a, USF, v-Myb, and C/EBP in the fragment in question. Mutation of cis-elements for C/EBP reduced significant HMGB1 promoter activity induced by Tax. These findings indicate that Tax enhances the expression of HMGB1 gene at the transcriptional level, possibly by interacting with C/EBP.