• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.337-340
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• 2004

The exactly reproduced prosody of a TTS system is one of the key factors that affect the naturalness of synthesized speech. In general, rules about prosody had been gathered either from linguistic knowledge or by analyzing the prosodic information from natural speech. But these could not be perfect and some of them could be incorrect. So we proposed artificial neural network(ANN)s that can be trained to team the prosody of natural speech and generate it. In learning phase, let ANNs learn the pitch and energy contour of center phoneme by applying a string of phonemes in a sentence to ANNs and comparing the output pattern with target pattern and making adjustment in weighting values to get the least mean square error between them. In test phase, the estimation rates were computed. We saw that ANNs could generate the prosody of a sentence.

• Polymer(Korea)
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• v.25 no.6
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• pp.789-795
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• 2001

In order to recover nickel ion from waste water containing heavy metals, the PAN fibrous ion-exchanger with primary, secondary amine groups and carboxyl group was synthesized by acid and base hydrolysis. The hydrolysis yield of PAN fiber in acid solution was higher than base solution. The swelling ratio and ion-exchange capacity of PAN fiber which was synthesized in 1N $H_2SO_4$ solution at $80^{\circ}C$ for 7 hrs appeared 71.2% and 1.95 meq/g respectively. We investigated that the adsorption of nickel ion was approached 1.44 meq/g at 50 min and the maximum adsorption capacity of ion-exchanger was 2.48 meq/g. We confirmed that the $Ni^{+2}$ adsorption ability of the synthesized PAN fibrous ion-exchanger in this study is excellent.

• Journal of Korean Society of Steel Construction
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• v.29 no.4
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• pp.311-321
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• 2017

This paper deals with the flexural performance of a composite girder system designed to readily form a composite section without a formwork and to easily realize multistage preflexing and prestressing. After a 3-Dimensional finite element modeling for construction stage analysis, the parametric numerical analysis was performed to analyse the stress distribution on the composite girder sections and the prestressing effects along with concrete pouring method and strand tensioning method. Based on the stress distribution analysis, a favorable construction stage model has been rationally chosen and then the ultimate flexural strengths were evaluated to conduct a comparative study, which exceed the nominal flexural strength suggested by the current design specification(ASD). It can be concluded that the proposed composite girder and fabrication procedure should have a sufficient structural performance.

• Korean Journal of Plant Resources
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• v.9 no.3
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• pp.274-278
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• 1996

This study was conducted to examine the dry matter production and leaf photosynthesis under different fertilizer application in Yacon(Polymnia sonchifolia)plants. Under field conditions, dry matter production of stable mature application plot(S-1) was much larger than non-treated control plot(CTL), but bulb dry weight of 10kg nitrogen application plot per 10a (N-10) was not differentiated from CTL. The maximum photosynthetic rates increased in Yacon plants grown at S-1 while in the rates of CTL reduced under glasshouse in the same treated pot condition. The optimum temperature for the highly photosynthetic rates is about $34{\pm}3^{\circ}C$, and the rates did decrease by stomatal resistance below 28℃. The estimated light saturation point was $1200{\mu}mol{\cdot}m^{-2}s^1$. The results of this study indicate that soil conditions were highly related to dry matter production and leaf photosynthesis rate in Yacon plants.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2007.11a
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• pp.187-192
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• 2007

A project is being implemented to develop the long distance energy transport technology using the chemical reactions. This project can be classified into three main research categories covering heat recovery reaction, long distance energy transport, and heat generation reaction. In this study, the methanol is selected as a system material since it shows several unique superior characteristics as follows: gaseous state of reactant and product, large heat of reaction, high yields of reaction at relatively low temperature, and also steady and economical supply. Furthermore, it is anticipated that the outcomes of this study can be widely applied to the related industries. A feasibility study was carried out to evaluate the economics of this technology which study was based on the following case: 10,000 households, 15km distance energy transportation, utilization of waste heat from power plant.

• Korean Journal of Poultry Science
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• v.45 no.2
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• pp.109-118
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• 2018

A great progress in genetic selection, nutrition and management practices has contributed to the improved growth rate of broilers and egg production in laying hens. For the increased productivity of modern poultry, a healthy chicken liver needs to cope with the increased metabolic demands. The liver is the major site of de novo fatty acid synthesis; therefore, hepatic lipogenesis is crucial for producing better quality meat and eggs. When de novo lipogenesis exceeds the capacity of lipid metabolism and secretion, large amounts of lipids accumulate in the liver of broilers, leading to a fatty liver. Upon onset of egg-laying in hens, lipids including free fatty acids, triglycerides, and phospholipids are dramatically increased in blood plasma for the synthesis of yolk precursors in oocytes. Productive hens with fatty liver often have hemorrhagic syndrome and sudden death due to the heavy demands of yolk synthesis, which burdens the liver. Understanding the lipid metabolism and hepatic lipid disorders is a key point in the improvement of the growth and production of chickens. This review focuses on the recent studies on lipid metabolism, the hepatic lipid disorders, and the prevention or reduction of fatty liver in poultry.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.88-88
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• 2017

Zn코팅은 우수한 내식성과 경제성을 바탕으로 자동차나 건축자재 등 산업의 전반적인 분야에서 광범위하게 사용되고 있다. 하지만 최근 한정된 Zn의 매장량으로 인한 원자제의 가격상승과 습식 도금과정의 환경오염 물질 배출 문제가 기존 Zn 코팅의 약점으로 지적되고 있다. 따라서 새로운 원소의 첨가로 인한 Zn의 사용량 감소나 친환경적인 공정방법을 적용하는 연구가 대두되고 있다. 최근의 연구 결과에 따르면 Zn-Mg 합금이 다른 Zn계 합금에 비해 내식성이 우수하며, 이와 같은 우수한 내식성은 $Mg_2Zn_{11}$, $MgZn_2$와 같은 Mg-Zn 이원계의 합금상에 의한 것으로 알려져 있다. 따라서 본 연구에서는 친환경적인 비대칭 마그네트론 스퍼터 공정을 활용하여 다양한 공정조건 하에서 Zn-Mg 박막을 합성하여 최적의 공정 조건을 도출하고자 하였다. Zn-Mg 박막 합성 시 Mg타겟의 조성은 3~10 wt.%로 변화하였으며 Zn-Mg 합금 타겟의 온도를 제어하여 박막의 Mg 조성과 타겟 온도가 Zn-Mg 도금강의 내식성 및 밀착성에 미치는 영향을 평가하였다. 합성된 Zn-Mg 박막은 FE-SEM, EDS, XRD를 사용하여 미세조직, 두께, Mg 조성, 합금상 등을 분석하였으며, 염수분무시험 및 0T 굽힘 시험을 활용하여 Zn-Mg 박막의 내식성 및 내식성을 비교 분석하였다. FE-SE및 EDS분석 결과 Zn-Mg 박막의 Mg 조성은 합금 타겟의 조성이 증가함에 따라 증가하였으며, Mg 함량이 증가할수록 미세구조가 치밀하게 변화하였다. 또한 Zn-Mg 박막 합성 중 타겟의 온도가 상승할수록 박막의 치밀도는 감소하였다. XRD분석 결과 박막을 이루는 주요 합금상은 Zn상과 $Mg_2Zn_{11}$상이며 본 연구에서는 증착 조건에 따른 합금상의 큰 변화는 보이지 않았다. 염수분무실험 및 밀착성 평가 결과 박막의 미세조직이 치밀할수록 Zn-Mg 도금강의 내식성은 향상되었으나, 밀착성은 오히려 감소하는 경향을 나타내었다. 이러한 결과는 Zn-Mg 박막이 치밀한 미세구조일수록 부식환경에서의 강판에 대한 보호 효과는 증가하는 반면, 변형 시 박막의 파괴로 인한 박리 현상이 가속되기 때문으로 판단된다.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.587-591
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• 2007

6-(10-Alkylphenothiazine-3-vinylene)-2-methyl-4-dicyanomethylene-4H-pyran derivatives were synthesized by Knoevenagel condensation. They are red-emitting materials for organic light emitting device (OLED) which composed of electron donor of 6-(10-Alkylphenothiazine-3-vinylene) groups and electron acceptor of -2-methyl-4-dicyanomethylene-4H-pyran groups by a conjugated structure. The structural properties of reaction products were analyzed FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visibles and PL properties can be determined by exitation spectra and emission spectra, respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.88-88
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• 2018

DLC(Diamond Like Carbon) 박막은 높은 열전도도, 큰 전기저항, 높은 강도 등의 다이아몬드와 유사한 특성을 가지고 있으면서 저온 저압에서도 합성이 가능하고, 합성 조건에 따라 물리 화학적 특성도 넓게 조절 할 수 있으며 상대적으로 넓은 면적에서 균일하고 평활한 박막의 합성이 가능하여 산업적 응용 면에서도 경쟁력을 갖추고 있다[1]. 이러한 DLC 박막을 합성함에 있어서 RF-PECVD(Radio Frequency Plasma Enhanced Chemical Vapor Deposition) 방법은 PECVD 방법 중 가장 보편적으로 사용되고 또 캐패시터 타입의 RF-PECVD 방법은 균일한 대면적 증착과 대량생산이 가능하다[1,2]. 본 연구에서는 우수한 특성을 갖는 DLC 박막의 증착 조건을 찾기 위해 캐패시터 타입의 RF-PECVD를 사용하여 공정 가스의 유량과 RF Power를 변화하여 박막을 증착하고, 증착된 박막의 특성을 연구하였다. DLC 박막은 ITO(Indium Tin Oxide) 유리 기판 위에 $100^{\circ}C$에서 5 min 동안 아세틸렌($C_2H_2$) 가스를 사용하여 가스 유량과 RF Power를 변화하여 증착하였다. 증착된 DLC 박막의 특성은 투과도, 평탄도, 두께를 측정하여 비교하였다. 가시광선 영역(380-780 nm)에서 투과도를 측정한 결과 ITO 유리 기판을 기준으로 한 DLC 박막의 투과도는 가시광선 영역 평균 94.8~98.8% 사이의 값으로 매우 높은 투과율을 나타내었다. 투과도는 가스 유량이 증가함에 따라 증가하는 경향을 나타내었고, RF Power의 변화에는 특정한 변화를 나타내지 않았다. 박막의 평탄도($R_a$, $R_{rms}$)와 두께는 AFM(Atomic Force Microscope)을 사용하여 측정하였다. 평탄도 $R_{rms}$는 0.8~3.3 nm, $R_a$는 0.6~2.5 nm 사이를 나타내었고 RF Power와 가스 유량의 변화에 따른 경향성을 나타내지는 않았다. 두께는 RF Power 25 W에서 55 W로 증가함에 따라 증가하는 경향을 나타내었으나 70W에서는 가스의 유량에 따라 상이한 결과를 나타내었다.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.481-485
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• 1998

Hydrated aluminum sulfate, an inorganic polymer, was synthesized from kaolin in $H_2SO_4$ solution using microwave energy. The maximum rates of alumina extracted from calcined kaolin were 72.8% in a conventional process ($80^{\circ}C$, 1M, and 180min) and 99.9% in a microwave process ($90^{\circ}C$, 1M, and 60 min). Compared with the conventional one, the hydrated aluminum sulfate synthesized under the microwave process had layer structure consisting of plate-shaped large grains. After synthesis and then calcination at $1100^{\circ}C$, both products on conventional and microwave processes were ${\gamma}-Al_2O_3$ with agglomerated powders of spherical shape. The specific area of the products in conventional and microwave processes were 113.5 and $106.6m^2/g$, and their average grain sizes were 46.5 an $26.3{\mu}m$, respectively.