• 한국자기학회지
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• 제16권5호
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• pp.234-239
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• 2006

교환 결합력을 갖는 CoFe/MnIr 박막 시료에서 100 MHz$\sim$9 GHz의 주파수 범위에서 마이크로파 투자율을 측정하였으며, 이들 결과는 Landau-Lifshitz-Gilbert 이론을 사용하여 분석 하였다. 초기투자율 및 강자성 공명주파수는 CoFe의 두께 및 일방이방성에너지(unidirectional anisotropy)에 따라서 조절이 가능하며, 특히 공명주파수는 최대 20 GHz까지 조율이 가능하다. 따라서 마이크로파 대역에서 고투자율 및 저손실 특성을 갖는 CoFe/MnIr 재료는 수 GHz 대역에서 작동하는 마이크로파 부품에 적용 가능하다.

• 대한조선학회논문집
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• 제57권3호
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• pp.152-159
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• 2020

Ship owners had pursued higher benefits by demanding the new design and construction of ships with higher operational efficiency. There was a necessity for shipyards to suggest a more economical design and advanced operation concept in order to meet the demands. Especially, since BOG combustion and activation of the re-liquefaction unit had to be taken into account in ship design in addition to fuel oil and gas consumption, the evaluation of the operating efficiency considering the technological trends was necessary. In this paper, it was aimed to study the design philosophy and operation strategy by considering the effect of fuel oil and gas consumption, BOG combustion, and activation of the re-liquefaction unit on the operating cost for laden voyage according to ship speed, BOR, and activation of the re-liquefaction unit. For this purpose, the costs were acquired by conducting the sailing simulation of an LNGC based on a mathematical model including the maneuvering equations of motion. The design philosophy and operation strategy was reviewed in terms of the operating cost.

• 한국가스학회지
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• 제25권1호
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• pp.7-13
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• 2021

재액화 드럼은 과냉각된 LNG를 증발가스에 직접 분사하기 위해 상부에 스프레이 노즐을 설치하고, 기액 분리가 용이하도록 데미스터를 설치한 제품으로, 소형 재액화 설비의 재액화 효율을 높이기 위해 개발한 제품이다. 드럼의 상온 내압기밀시험에서는 설계압력의 1.5배 이상의 압력에서도 누설(Leak)이 없었으나, 단열성능시험 중 온도변화에 따른 수축/팽창으로 인해 볼트풀림 현상이 발생하였다. 제품의 지속적인 사용을 위해 플랜지 결합부의 단열 시공은 탈부착이 가능하도록 개발하였으며, 기존 단열과의 열침입량 비교 결과 드럼 내 유입 유량 대비 매우 미미함을 확인하였다.

• Biomolecules & Therapeutics
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• 제17권1호
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• pp.12-16
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• 2009

One of the WHSC1/MMSET/NSD2 variant RE-IIBP is a histone H3-K27 methyltransferase with transcriptional repression activity. Overexpression of RE-IIBP in various types of leukemia suggests it's role in leukemogenesis. Here we identify two proteins, KRAB zinc finger protein ZNF 350 and enolase-1 as RE-IIBP interacting proteins by yeast two-hybrid screening and confirmed direct interaction in vivo and in vitro. Both proteins have been known for their role in transcriptional repression. Reporter assays using transient transfection demonstrated that both ZNF 350 and enolase-1 proteins synergistically repressed transcription with RE-IIBP, respectively. These results indicate both proteins have roles in RE-IIBP mediated transcriptional repression by involving co-repressor complex.

• 한국분말재료학회지
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• 제12권5호
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• pp.357-361
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• 2005

Fe-doped skutterudite $CoSb_3$ with a nominal composition of $Fe_{x}Co_{4-x}Sb_{12}(0\;{\le}\;x\;{\le}\;2.5)$ has been synthesized by mechanical alloying (MA) of elemental powders, followed by hot pressing. Phase transformations during mechanical alloying and hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase in the form of marcasite structure $FeSb_2$ was found to exist in case of $x\;{\ge}\;2$, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe substitution up to x=1.5 with Co in $Fe_{x}Co_{4-x}Sb_{12}$ appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.

• 천문학논총
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• 제27권5호
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• pp.419-429
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• 2012

In this paper, we propose a new re-quantization method after FFT processing to prevent the distortion of correlation result of VCS (VLBI Correlation Subsystem). The re-quantization is used to rearrange the data bit so as to reduce the data rate processed as 16-bit of FFT result of VCS. Having done this procedure, we found that the distorted spectrum of correlation result occurred in the delay tracking experiments by the re-quantization method introduced for initial design of VCS. In order to solve this, two kinds of re-quantization method, that is, the comparison and selection-type, are proposed. The first is to re-quantize the FFT result as a valid-bit by comparing with the input data after determining the adequate threshold. The second is manually to select the valid-bit of FFT result after finding the valid-field of data according to the bit-distribution of input data. We confirmed that the second is more effective compared with the first through the experimental result, and it will be implemented without so much modification of applied method in the condition of the limited resource of FPGA. The re-quantization is, however, carried out with 4-bit in the proposed second method for FFT result, and then the distortion of correlation result is also appeared. To fix this problem, the bit for re-quantization is extended to 8-bit. The proposed 8-bit selection-type is effectively verified so that the distortion of correlation result disappeared by applying to VCS in consequence of the simulation and correlation experiments.

• Elastomers and Composites
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• 제58권1호
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• pp.32-43
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• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1311-1314
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• 2008

We have developed new electrical dopants of rhenium oxide ($ReO_3$) and cupper iodide (CuI) as p-dopants and rubidium carbonate ($Rb_2CO_3$) as an n-dopant, respectively. $ReO_3$ has advantage of low temperature evaporation (about $300^{\circ}C$) with enhanced device stability. Various kinds of high performance organic light emitting diodes have been realized, including bottom emission, tandem, and top-emission OLEDs.

• E2M - 전기 전자와 첨단 소재
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• 제6권1호
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• pp.1-7
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• 1993

최근에 있어서 광자기기록 재료의 연구개발은 실용화 단계에 이른 비정질 RE-TM막을 중심으로 하여 내식성, 보호막, 기판재료, 양산기술 향상 등에 촛점이 맞추어져 있다. 한편 장래의 문제로서 일층 고성능화와 보다 생산성이 놓은 재료의 개발이 기대되고 있다. 고성능화를 위해서는 반도체 레이저의 고출력, 단파장화가 가장 효과적이라고 생각되나 이에 맞는 기록재료의 개발연구도 병행되어 져야한다. 기존의 반도체 레이저 범위안에서는 RE-rich의 막을 기록층으로 하고 적당한 재생층을 갖는 2층 막으로 부터 밀도 및 속도의 양면에서 최고의 성능이 얻어지고 있다. 장래 단파장 반도체 레이저가 개발된다면 경희토류를 이용한 막에서 고성능화가 아루어질 것으로 보이며 또한 Pb/Co, Pt/Co등 자성다층막이 RE-TM 재료의 단점을 보완하고 한층 더 고밀도화를 이룩할 수 있는 차세대 광자기기록 재료로 기대를 모으고 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.392-395
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• 2006

The configuration of coaxial co-rotating contained in shroud provides a useful model for investigating the characteristics of flow in the HDD. Reynolds number is defined as $Re_R={\Omega}{R_o}^2/{\upsilon},\;Re_H={\Omega}R_oH/{\upsilon}$ in present study. An experimental investigation was performed for turbulence profiles and PSD distribution and vortices frequency behavior for various range of $Re_R=2.43{\times}10^4{\sim}3.61{\times}10^5$. A laser Doppler anemometry (LDA) is used to obtain the velocity field of unobstructed co-rotating disks flow. Airflow pattern visualization between inner and outer region was compared with turbulence profiles measured from LDA. Outer detached shear layer and dead-zone without oscillating velocity fluctuation to circumferential mean were quantitively traced.