• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.376-381
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• 2019

In this work, we evaluated the structural, electrical and optical properties of $Ge_8Sb_2Te_{11}$ and Cu-doped $Ge_8Sb_2Te_{11}$ thin films prepared by rf-magnetron reactive sputtering. The 200-nm-thick deposited films were annealed in a range of $100{\sim}400^{\circ}C$ using a furnace in an $N_2$ atmosphere. The amorphous-to-crystalline phase changes of the thin films were investigated by X-ray diffraction (XRD), UV-Vis-IR spectrophotometry, a 4-point probe, and a source meter. A one-step phase transformation from amorphous to face-centered-cubic (fcc) and an increase of the crystallization temperature ($T_c$) was observed in the Cu-doped film, which indicates an enhanced thermal stability in the amorphous state. The difference in the optical energy band gap ($E_{op}$) between the amorphous and crystalline phases was relatively large, approximately 0.38~0.41 eV, which is beneficial for reducing the noise in the memory devices. The sheet resistance($R_s$) of the amorphous phase in the Cu-doped film was about 1.5 orders larger than that in undoped film. A large $R_s$ in the amorphous phase will reduce the programming current in the memory device. An increase of threshold voltage ($V_{th}$) was seen in the Cu-doped film, which implied a high thermal efficiency. This suggests that the Cu-doped $Ge_8Sb_2Te_{11}$ thin film is a good candidate for PRAM.

• 대한금속재료학회지
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• 제48권3호
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• pp.256-261
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• 2010

In this work, high-k dielectric stacks of $HfO_2$ and $HfO_2$/$Al_2O_3$/$HfO_2$ (HAH) were deposited on $SiO_2/Si$ substrates by atomic layer deposition as charge trapping layers in charge trapping devices. The structural stability and the charge trapping characteristics of such stacks were investigated using Metal-Alumina-Hafnia-Oxide-Silicon (MAHOS) structure. The surface roughness of $HfO_2$ was stable up to 11 nm with the insertion of 0.2 nm thick $Al_2O_3$. The effect of the thickness of the HAH stack and the thickness of intermediate $Al_2O_3$ on charge trapping characteristics were investigated for MAHOS structure under various gate bias pulse with duration of 100 ms. The threshold voltage shift after programming and erase showed that the memory window was increased with increasing bias on gate. However, the programming window was independent of the thickness of HAH charge trapping layers. When the thickness of $Al_2O_3$insertion increased from 0.2 nm to 1 nm, the erase window was decreased without change in the programming window.

• Animal Bioscience
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• 제36권9호
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• pp.1414-1425
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• 2023

Objective: Long chain n-3 polyunsaturated fatty acids (PUFA) exert positive effects on human health. The long chain n-3 PUFA of pork can be increased by adding fish oil to the diet. Due to the cost and availability of fish oil an alternative source must be found. Methods: This study evaluated the effect of five dietary oils on meat quality, fatty acid composition and lipid stability. The five diets contained 1% palm oil (Control), 1% soya oil, 1% linseed oil, 1% fish oil, and 1% Echium oil, respectively. The trial consisted of 60 gilts, randomly allocated to five groups. Results: All color parameters, extractable fat content, fat free dry matter, and moisture content of the m. longissimus muscle were unaffected by dietary treatment. Consumers and a trained sensory panel could not detect a difference between the control samples and the Echium oil sample during sensory analysis. Samples containing higher levels of PUFA (soya, linseed, fish, and Echium oil) had higher levels of primary and secondary lipid oxidation products after refrigerated and frozen storage. However, these values were still well below the threshold value where off flavors can be detected. The Echium oil treatment had significantly higher levels of long chain PUFA than the linseed oil treatment, but it was still significantly lower than that of the fish oil treatment. Conclusion: Echium oil supplementation did not increase the levels of n-3 to the same extent as fish oil did. The result did however suggest that Echium oil can be used in pig diets to improve muscle long chain n-3 fatty acid content without any adverse effects on meat quality when compared to linseed, soya, and palm oil.

• 대한토목학회논문집
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• 제28권1A호
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• pp.79-87
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• 2008

본 논문은 고정지점을 갖는 낮은 아치의 면내 안정성에 관하여 연구를 수행하였다. 연구에 사용된 아치의 형상은 포물선 형태이며, 하중은 등분포 하중이다. 일반 아치의 비선형 지배 미분 방정식을 이용하여 고정지점을 갖는 낮은 아치의 증분 형태 하중-변위 관계와 좌굴 하중을 유도하였다. 연구 결과, 아치의 좌굴형상(대칭 혹은 비대칭 좌굴)은 아치의 라이즈비와 세장비의 함수로 이루어진 무차원 라이즈 H 와 밀접한 관계가 있는 것으로 나타났다. 이 밖에 본 연구에서는 고정지점을 갖는 낮은 아치의 좌굴 형상을 구분하는 경계와 좌굴하중을 제안하였다. 이러한 제안식은 일련의 유한요소해석 결과들과 비교하였으며, 본 연구의 제안식은 고정지점을 갖는 낮은 아치의 좌굴 하중을 적절히 예측할 수 있는 것으로 나타났다.

• 한국소프트웨어감정평가학회 논문지
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• 제15권1호
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• pp.71-78
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• 2019

광대역 광통신 시스템에 사용되는 레이저는 우수한 주파수 선택성과 모드 안정성을 가져야한다. DFB(Distributed Feedback) 레이저는 고주파로 전류 변조를 하더라도 발진 주파수의 변화가 적다. 본 연구에서는 무반사 코팅을 하지 않은, 두 거울 면을 가진 1.55um의 파장을 갖는 DFB 레이저에서 이득 격자와 굴절률 격자가 동시에 존재할 때, 시뮬레이션 소프트웨어를 개발하여 종 방향으로의 발진 모드의 빔 분포를 해석하였다. 굴절률 격자와 이득 격자가 거울 면에서 갖는 위상 값의 변화에 따라서 DFB 레이저의 발진 모드에 대한 빔 분포 |R(z)|와 |S(z)|, 그리고 방사전력비 P_l/P_r를 비교 검증하였다. 거울 면에서의 격자 위상에 관계없이 발진 모드의 문턱 전류를 낮추고 주파수 안정성을 높이기 위해서는, κL이 8보다 커야한다.

• 한국전기전자재료학회논문지
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• 제36권6호
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• pp.588-593
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• 2023

The advantage of OTFT technology is that large-area circuits can be manufactured on flexible substrates using a low-cost solution process such as inkjet printing. Compared to silicon-based inorganic semiconductor processes, the process temperature is lower and the process time is shorter, so it can be widely applied to fields that do not require high electron mobility. Materials that have utility as electrode materials include carbon that can be solution-processed, transparent carbon thin films, and metallic nanoparticles, etc. are being studied. Recently, a technology has been developed to facilitate charge injection by coating the surface of the Al electrode with solution-processable titanium oxide (TiOx), which can greatly improve the performance of OTFT. In order to commercialize OTFT technology, an appropriate method is to use a complementary circuit with excellent reliability and stability. For this, insulators and channel semiconductors using organic materials must have stability in the air. In this study, carbon-doped Mo (MoC) thin films were fabricated with different graphite target power densities via unbalanced magnetron sputtering (UBM). The influence of graphite target power density on the structural, surface area, physical, and electrical properties of MoC films was investigated. MoC thin films deposited by the unbalanced magnetron sputtering method exhibited a smooth and uniform surface. However, as the graphite target power density increased, the rms surface roughness of the MoC film increased, and the hardness and elastic modulus of the MoC thin film increased. Additionally, as the graphite target power density increased, the resistivity value of the MoC film increased. In the performance of an organic thin film transistor using a MoC gate electrode, the carrier mobility, threshold voltage, and drain current on/off ratio (I_on/I_off) showed 0.15 cm²/V·s, -5.6 V, and 7.5×10⁴, respectively.

• 한국건축시공학회지
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• 제23권5호
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• pp.629-638
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• 2023

본 논문에서는 건설현장 작업자의 실내 위치 추적을 위한 새로운 방법을 소개한다. 전통적으로 GPS및 NTRIP과 같은 기술은 주로 야외에서 효과적인 위치 확인을 제공하는 데 사용되었습니다. 그러나 이러한 기술은 실내에서 사용할 경우 정확도가 떨어지는 문제가 있습니다. 이러한 문제를 해결하기 위해 본 논문에서는 Aruco marker를 활용하여 작업자의 위치를 추적하는 방법을 제안한다. Aruco marker는 작업자와 마커 사이의 거리를 측정하는 데 사용됩니다. 이 새로운 접근 방식은 기존 위치 확인 방법에 비해 더욱 정확한 실내 위치 확인을 제공합니다. 작업자 위치를 실시간으로 확인할 수 있어 작업 일정을 최적화하고 작업자 간 협업을 촉진합니다. 따라서 Aruco marker를 활용한 실내 측위 방식은 기존의 기술의 문제점을 보완하는 실내 위치 확인 시스템으로 활용될 수 있다.

• 한국진공학회지
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• 제14권4호
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• pp.258-262
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• 2005

본 연구는 실리콘 질화막 박막을 덮개층으로 사용하여 탄소나노튜브를 성장하고, 성장된 나노튜브의 전자방출특성을 조사하였다. 탄소 나노튜브는 triode PE-CVD 장치에 의해 성장되었으며, 탄소나노튜브의 밀도는 실리콘 질화막의 두께에 따라 크게 변하였다. 탄소 나노튜브의 밀도가 $10^{4}$/$cm^{2}$에서 전자방출 특성이 가장 우수하였으며, 이때 전자방출특성은 문턱전계 1.2 V/$\mu$m, 전류밀도는 3.6 V/$\mu$n의 전기장에서 0.17 mA/$cm^{2}$으로 측정 되었다. 또한, 진공 챔버에서 질소($N_{2}$) 분위기 하에서 전자방출 안정성을 조사하였으며, 탄소나노튜브의 밀도가 감소함에 따라 전자방출 안정성이 향상되었고, 탄소나노튜브의 밀도가 $10^{4}$/$cm^{2}$ 인 경우 $1\times10^{-4}$ A/$cm^{2}$ 이상의 전류가 흐르는 특성을 보였으며, 이 경우 $1\times$$10^{-5}$ Torr의 압력하에서 방출 전류의 안정도는 최소인 $2\%$를 유지하였다.

• Animal Bioscience
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• 제35권12호
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• pp.1850-1859
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• 2022

Objective: The quantitative reverse transcription polymerase chain reaction (qPCR) is the most accurate and reliable technique for analysis of gene expression. Endogenous reference genes (RGs) have been used to normalize qPCR data, although their expression may vary in different tissues and experimental conditions. Verification of the stability of RGs in selected samples is a prerequisite for reliable results. Therefore, we attempted to identify the most stable RGs in the hypothalamic-pituitary-gonadal (HPG) axis in sows. Methods: The cycle threshold values of nine commonly used RGs (18S, HPRT1, GAPDH, RPL4, PPIA, B2M, YWHAZ, ACTB, and SDHA) from HPG axis-related tissues in the domestic sows in the different stages of estrus cycle were analyzed using two RG-finding programs, geNorm and Normfinder, to rank the stability of the pool of RGs. In addition, the effect of the most and least stable RGs was examined by normalization of the target gene, gonadotropin-releasing hormone (GnRH), in the hypothalamus. Results: PPIA, HPRT1, and YWHAZ were the most stable RGs in the HPG axis-related tissues in sows regardless of the stages of estrus cycle. In contrast, traditional RGs, including 18S and ACTB, were found to be the least stable under these experimental conditions. In particular, in the normalization of GnRH expression in the hypothalamus against several stable RGs, PPIA, HPRT1, and YWHAZ, could generate significant (p<0.05) elevation of GnRH in the preovulatory phase compared to the luteal phase, but the traditional RGs with the least stability (18S and ACTB) did not show a significant difference between groups. Conclusion: These results indicate the importance of verifying RG stability prior to commencing research and may contribute to experimental design in the field of animal reproductive physiology as reference data.

• 한국인터넷방송통신학회논문지
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• 제9권2호
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• pp.7-12
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• 2009

퍼지 형태학적 형상 분해를 이용한 얼굴인증 과정에서 퍼지척도를 기반으로 한 특징추출 방법을 제안하였다. 형태소에 관계하는 영상정보와 퍼지척도를 기반으로 한 가중치에 대하여 무게중심을 이용하여 인접정보가 고려되었다. 이에 의한 형태학적 침식과 팽창연산자를 정의하여 얼굴영역의 특징점 추출시 기존의 방법보다 4배 이상의 많은 분해영상을 얻을 수 있었다. 결국 특징 벡터를 이용하여 얼굴인증을 수행한 실험결과 기존의 형상분해에 의한 방법보다 특징점 추출과 임계값의 안정성을 확보하여 인식 결과에서 비교우위를 가질 수 있었다.