• 한국세라믹학회지
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• 제44권8호
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• pp.403-406
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• 2007

Ferroelectric Ce-doped $Bi_4Ti_3O_{12}$ (BCT) thin films were deposited by liquid delivery metal organic chemical vapor deposition (MOCVD) onto a $Pt(111)/Ti/SiO_2/Si(100)$ substrate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface, and the cross-section morphology of the deposited ferroelectric flims. After annealing above $640^{\circ}C$, the BCT films exhibited a polycrystalline structure with preferred (001) and (117) orientations. The BCT lam capacitor with a top Pt electrode showed a large remnant polarization ($2P_r$) of $44.56{\mu}C/cm^2$ at an applied voltage of 5 V and exhibited fatigue-free behavior up to $1.0{\times}10^{11}$ switching cycles at a frequency of 1 MHz. This study clearly reveals that BCT thin film has potential for application in non-volatile ferroelectric random access memories and dynamic random access memories.

• 대한기계학회논문집B
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• 제27권9호
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• pp.1335-1341
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• 2003

This paper describes the process of nanoparticle synthesis by laser ablation of microparticles and consolidated sample. We have generated nanoparticles by high-power pulsed laser ablation of AI, Cu and Ag microparticles using a Q-switched Nd:YAG laser (wavelength 355nm, FWHM 6ns, fluence $0.8{\sim}2.0J/cm^2$). Microparticles of mean diameter $18{\sim}80{\mu}m$ are ablated in the ambient air. The generated nanoparticles are collected on a glass substrate and the size distribution and morphology are examined using a scanning electron microscope and a transmission electron microscope. The effect of laser fluence, collector position and compacting pressure on the distribution of particle size is investigated. To better understand the process of laser ablation of microparticle(LAM), we investigated the Nd: YAG laser-induced breakdown of Cu microparticle using time-resolved optical shadow images. Nanosecond time-resolved images of the ablation process are also obtained by laser flash shadowgraphy. Based on the experimental results, discussions are made on the dynamics of ablation plume.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.269-277
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• 2020

Bao Loc City is the new tourism destination in Lam Dong province, Vietnam, where more and more tourists have been drawn to pay a visit. This study aims to test the correlative impact of tourism service quality factors on satisfaction of the tourists who have visited Bao Loc City. The key theory used in this study is SERVQUAL scale. The survey sample consists of 350 tourists who stayed overnight in Bao Loc City in the last quarter of 2019; 315 valid survey questionnaires could be used for the analysis. The research applied Cronbach's Alpha, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), structural equation modeling (SEM), and bootstrap test. The results show that the satisfaction of the tourists who have visited Bao Loc City has been affected statistically by three factors: (1) Responsiveness; (2) Reliability; and (3) Empathy, which were ranked by descending importance. Surprisingly, the research found that Tangibles and Assurance do not have an impact on tourists' satisfaction towards Bao Loc City. The research formulates some suggestions to the city policy-makers and the tourism businesses management in Bao Loc City in order to enhance tourists' satisfaction through improving the tourism service quality at Bao Loc City.

• 한국레이저가공학회지
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• 제13권2호
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• pp.10-16
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• 2010

Laser-assisted machining is dependent on absorbed energy density into workpiece. Generally, the absorptivity of laser beam is dependent on wave length of laser, materials, surface roughness, etc. Various shapes and energy densities for beam irradiation can be used to laser-assisted machining. In this thesis, efficient method of heat source modeling was developed and designed by using one fundamental experimental trials. And then, laser-assisted machining of rod-shaped cast iron was simulated by using commercial FEM code MARC. Simulations and experiments with various conditions were carried out to determine suitable condition of pre-heating for laser-assisted turning process. Temperature distribution of cutting zone could be predicted by simulation.

• 한국레이저가공학회지
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• 제12권1호
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• pp.25-33
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• 2009

In laser-assisted machining (LAM), laser beam is used to locally increase the temperature of a workpiece and thus to enhance the machinability. In order to set the temperature of the material removal area of a workpiece at an optimal value, process parameters, such as laser power, feed rate, and rotational velocity, have to be carefully controlled. In this work, the effects of laser power and feed rate on the temperature distribution of a silicon nitride rotating at a constant velocity were experimentally investigated. Using a pyrometer, temperatures at various locations of the silicon nitride were measured both in circumferential and axial directions. The measured temperatures were fitted to a quadratic equation to approximate the temperature at the cutting location. The machining results showed that cutting force and tool wear were decreased when the temperature at the cutting location was increased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.382-385
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• 2006

한국지질자원연구원은 1997년부터 새로운 에너지 자원으로 활용 가능성을 포함하고 있는 가스 하이드레이트를 조사하기 위해 동해 일원에서 탄성파탐사를 실시하고 있다. 탄성파 반사 자료로부터 가스 하이드레이트 부존여부를 확인하는 방법은 해저면과 평행하면서 위상이 반대로 나타나는 고진폭 반사파 BSR (Bottom Simulating Reflection)과 BSR상부에서의 진폭감소, 하부에서 진폭증가와 구간속도 감소 등을 들 수 있다. 여기에서는 가스 하이드레이트 탐사자료에 대한 일반자료처리와 함께 BSR을 포함하고 있는 탄성파 반사자료에 대해 코드 병렬화된 PSPI를 이용하여 깊이영역 구조보정을 실시하였다. 고용량 탐사자료로 구성된 탄성파 반사자료에 깊이영역 구조보정을 적용하기 위해서는 고성능 컴퓨터와 병렬처리 기술이 필요하다. PSPI(Phase Shift Plus Interpolation)법은 적은 컴퓨터 계산량과 효율성 그리고 주파수 영역에서 구조적으로 병렬화가 용이한 특성을 지니고 있어 구조보정에 많이 이용되고 있다. 여기에서는 MPI(Message Passing Interface)-LAM을 이용하여 병렬코드화된 PSPI를 개발하고 인공합성모델과 동해 가스 하이드레이트 깊이영역 구조보정에 적응하였다.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.353-362
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• 2022

Small and medium businesses (SMEs) play a critical role in the economy, yet they are plagued by a shortage of finance. Determining the influence of cash sources both inside and outside the firm is critical to the company's survival and growth. As a result, the purpose of this research is to determine the impact of capital on the growth of SMEs in Vietnam. The key factors of this research are equity and liabilities, which are two proxies for a firm's capital. The data is based on the results of a survey conducted every two years from 2005 to 2015, which included over 2,600 SMEs in 20 processing and manufacturing industries in ten provinces and cities, including Hanoi, Hai Phong, Ho Chi Minh City, Ha Tay, Phu Tho, Nghe An, Quang Nam, Khanh Hoa, Lam Dong, and Long An. The findings show that characteristics such as equity capital, total workforce growth rate, and male entrepreneurs have a positive impact on enterprise growth, whereas liabilities, firm age, and export have a negative impact on enterprise growth. The study has demonstrated that equity has a positive impact while liabilities have a negative impact on the growth of Vietnamese SMEs.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.78-78
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• 2020

The Se San and Srepok river basins (2S) are the two major tributaries of the Mekong River, both of which originate in the territory of Viet Nam and flow to Cambodia to meet at Stung treng with the Sekong river (originating in Lao PDR) to form the 3S river basin before joining the Mekong mainstream. In the territory of Viet Nam, the 2S river basins are located in the Central Highlands including 5 provinces, arranged by geographical location from north to south namely Kon Tum, Gia Lai, Dak Lak, Dak Nong and Lam Dong. This is a region with a very important strategic position in terms of economy, politics and defense for the whole country with many potential advantages for economic development. However, the limited and vulnerable basin water resources are under the pressure of socio-economic development in line with increasing water demands for various sectors. In order to overcome the water management challenges, a long-term water resources planning has conducted to support the 2S River Basin Committee (RBC) in effective planning and operation as part of the WB Mekong-Integrated Water Resources Management (IWRM) Project. This paper introduces the outline and progress of the river basin planning using analytical DSS toolkits to analyze, evaluate and formulate the planning options.

• Journal of Plant Biotechnology
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• 제31권1호
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• pp.43-48
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• 2004

이탈리안 라이그래스의 최적 조직배양 조건을 확립하기 위하여 성숙종자로부터 최적 배발생 캘러스 유도조건 및 효율적인 식물체 재분화 체계를 확립하였다. 배발생 캘러스 유도시 첨가되는 auxin으로는 2,4-D가 가장 효율적이었으며, 5mg/L 2.4-D가 첨가된 MS배지에서 배발생 캘러스가 가장 높은 빈도로 유도되었다. 식물체 재분화는 배발생 캘러스를 1mg/L 2,4-D와 5mg/L BA가 첨가된 N6배지에서 배양했을 때 70%이상의 재분화율을 나타내었다. 기본배지의 종류에 따른 배양효율의 차이는 캘러스 유도에는 MS배지가, 식물체 재분화에는 N6배지가 효과적이었다. 배발생 캘러스의 형성율은 품종간에 큰 차이가 없었으나, 재분화 능력은 Jeanne 품종이 73%의 가장 높은 재분화율을 나타내어 품종간에 큰 차이를 나타내었다. 본 연구를 통하여 확립된 단기간 고효율 재분화 시스템은 분자육종을 통한 신품종 이탈리안 라이그래스의 개발에 유용하게 응용되어질 수 있을 것이다.

• 한국초지조사료학회지
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• 제31권2호
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• pp.107-112
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• 2011

본 시험은 이탈리안 라이그라스(Lolium multiflorum Lam.) 만생종의 생육단계별 건물생산성과 사료가치에 대한 기초자료를 제공하기 위히여 2000년부터 2002년까지 국립축산과학원 초지사료과 시험포장에서 수행되었다. 수원지역에서 이탈리안 라이그라스 만생종인 '화산101호'의 생육단계는 수양기, 출수시, 수전기 및 개화기가 각각 5월8일, 5월 18일, 5월 28일 및 6월 3일이었다. 생육단계별 건물 및 가소화영양소 총량은 수잉기에서 개화기까지 생육이 진전됨에 따라 유의적으로 증가하는 경향이었다. 건물수량은 수잉기(4,818 kg/ha)에서 출수시(7,244 kg/ha) 까지 10일 사이에 50%까지 증가하였다. 생육단계별 조단백질 함량은 수잉기 18.32%, 출수시 15.12%, 수전기 12.58% 및 개화기 12.36%로서 생육이 진행됨에 따라 점차적으로 감소하였으나 수전기와 개화기 사이에는 차이가 없었다. NDF와 ADF의 함량은 생육이 진행됨에 따라 점차적으로 증가하였고, TDN와 IVDMD 함량은 생육이 진전됨에 따라서 점진적으로 감소하는 경향이었다. 그러나 수전기에서 개화기 사이에는 사료가치의 차이가 거의 없었다. 이상의 결과를 종합해 볼 때, 이탈이란 라이그라스 만생종인 '화성 101호'의 알맞은 수확시기는 수전기에서 개화기 사이에 하는 것이 조사료 생상성 향상에 유리 할 것으로 사료된다.