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        검색결과 308

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment investigated the effects of feed additives of Sasa quelpaertensis Nakai (SQN) extract on Landrace pigs on economic traits such as the quality, physiological characteristics, and productivity. Sixteen pigs with an average age of 154 days were selected as experimental subjects. The experiment was conducted by dividing the group into eight pigs for the supplementation group, feeding with SQN extract, and another eight for the control group feeding without SQN extract. Water was fed ad libitum. On the 30th day, there was no significant difference between meat quality and productivity. However, the glucose and thyroxine were statistically lower with the supplementation group than with the control group (p<0.05). Also, the levels of creatinine difference between 1.18 ± 0.12 ㎎/㎗ with the supplementation group and 0.70 ± 0.06 ㎎/㎗ with the control group (p<0.05). However, all serum biochemistry values were within a normal range, with no health problems. The present study will help solve the problem of reducing the diversity of plant species in Halla Mountain by increasing the availability of the SQN as a pig feed additive.
        4,000원
        2.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An irradiation hardening of Inconel 718 produced by selective laser melting (SLM) was studied based on the microstructural observation and mechanical behavior. Ion irradiation for emulating neutron irradiation has been proposed owing to advantages such as low radiation emission and short experimental periods. To prevent softening caused by the dissolution of ' and '' precipitates due to irradiation, only solution annealing (SA) was performed. SLM SA Inconel 718 specimen was ion irradiated to demonstrate the difference in microstructure and mechanical properties between the irradiated and non-irradiated specimens. After exposing specimens to Fe3+ ions irradiation up to 100 dpa (displacement per atom) at an ambient temperature, the hardness of irradiated specimens was measured by nanoindentation as a function of depth. The depth distribution profile of Fe3+ and dpa were calculated by the Monte Carlo SRIM (Stopping and Range of Ions in Matter)-2013 code under the assumption of the displacement threshold energy of 40 eV. A transmission electron microscope was utilized to observe the formation of irradiation defects such as dislocation loops. This study reveals that the Frank partial dislocation loops induce irradiation hardening of SLM SA Inconel 718 specimens.
        4,000원
        3.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 IPA 기법을 이용하여 중국인 골프장 이용객의 골프장 선택속성 요인에 대한 재방문 의도 및 추천의도에 미치는 영향을 규명하는데 목적이 있다. 본 연구를 수행하고자 중국인 골프장 이용객 388명을 대상으로 설문조사를 실시하여 자료처리 및 IPA 분석을 실시한 결과, 다음과 같은 결론을 얻었다. 첫째 선택속성의 중요도는 직원 예절, 만족도는 식당 및 식음료 가격이 가장 높게 나타났다. 둘째, IPA 매 트릭스 분석 결과, 지속유지에는 8개, 집중개선은 14개, 낮은 우선순위는 5개, 과잉노력지양은 3개의 선택 속성이 분포하였다. 셋째 비용, 접근성, 코스시설, 부대시설, 캐디 전문성, 이용객 관리의 만족도가 재방문 과 추천 의도에 모두 영향을 미치는 것으로 나타났다. 본 연구는 중국인 골프장 이용객으로 한정하였기 때 문에 골프문화가 다른 국가에서 연구된 선행연구와는 그 결과를 비교하는데 있어 차이가 있을 수 있기 때 문에 문화의 다양성을 고려한 연구들이 향후에 진행되어야 할 것이다.
        4,600원
        4.
        2023.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AZO/Cu/AZO thin films were deposited on glass by RF magnetron sputtering. The specimens showed the preferred orientation of (0002) AZO and (111) Cu. The Cu crystal sizes increased from about 3.7 nm to about 8.5 nm with increasing Cu thickness, and from about 6.3 nm to about 9.5 nm with increasing heat treatment temperatures. The sizes of AZO crystals were almost independent of the Cu thickness, and increased slightly with heat treatment temperature. The residual stress of AZO after heat treatment also increased compressively from -4.6 GPa to -5.6 GPa with increasing heat treatment temperature. The increase in crystal size resulted from grain growth, and the increase in stress resulted from the decrease in defects that accompanied grain growth, and the thermal stress during cooling from heat treatment temperature to room temperature. From the PL spectra, the decrease in defects during heat treatment resulted in the increased intensity. The electrical resistivities of the 4 nm Cu film were 5.9 × 10-4 Ω ‧ cm and about 1.0 × 10-4 Ω ‧ cm for thicker Cu films. The resistivity decreased as the temperature of heat treatment increased. As the Cu thickness increased, an increase in carrier concentration resulted, as the fraction of AZO/Cu/AZO metal film increased. And the increase in carrier concentration with increasing heat treatment temperature might result from the diffusion of Cu ions into AZO. Transmittance decreased with increasing Cu thicknesses, and reached a maximum near the 500 nm wavelength after being heat treated at 200 °C.
        4,000원
        11.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        신재생에너지로서 수소에 대한 수요가 증가하고 있으나 기존의 화석 연료와 달리 수소는 연료 공급을 위한 전용 충전소가 필 요하며, 이러한 인프라 확보를 위해서 수소충전소의 위험성 평가가 선행되어야 한다. 따라서 본 연구에서는 정성적 위험성평가와 정량적 위험성 평가로 구분하여 수소충전소에 대한 위험성평가를 수행하였다. 정성적 평가는 Hazard and Operability Analysis(HAZOP) 기법을 사용 하여 Dispenser Module을 두 개의 Node로 평가하였으며, Criticality Estimation Matrix에 따라 Filter의 막힘으로 인한 사고와 고압 사고의 위험 도가 High Level로 평가되었다. 정량적 위험성 평가는 Hydrogen Korea Risk Assessment Module(Hy-KoRAM)을 사용하여 화재의 형상과 피해영 향범위를 나타냈고, 개인적 위험도와 사회적 위험도에 대한 평가를 수행하였다. 개인적 위험도는 수소충전소로부터 약 100m 떨어진 공공 시설 부근까지 추가적인 안전조치가 고려되는 As Low As Reasonably Practicable(ALARP) 구간의 위험도를 보였고, 사회적 위험도 역시 약 10명의 사망자가 발생할 사고빈도가 1E-04/year로 도출되며 ALARP 구간 내에 나타났다. 정성적·정량적 위험성 평가 결과, 공정 단계의 추 가적인 안전 조치와 수소충전소 부근의 제한구역 설정을 통하여 안전성 향상 방안을 제시하였다.
        4,000원
        12.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although monitoring of radon has been extensively implemented throughout South Korea, the risk assessment has been mainly limited to indoor environments such as schools, workplaces, and multi-use facilities, and evaluations have normally been performed separately. In this study, the differences in radon exposure according to two groups (< 1 and 1-6 years old) were evaluated considering various indoor and outdoor environments, timeactivity patterns, variations in radon concentrations, and dwelling type (single detached and apartment house) using Monte-Carlo simulation. The distribution and representative values of radon concentration by micro-environments were confirmed through the Anders-Darling test, and a uniform distribution was applied in case of uncertainty. The effective dose ranged from 1.81 ± 1.19 to 2.81 ± 3.02mSv/y. Comparing the levels recommended by EPA, WHO, and ICRP with the value of the 95th percentile of this study, it was found that the results for those dwelling in detached houses exceeded recommended levels. Infants that spend a lot of time in homes with relatively high levels of concentration of radon are assessed to be somewhat more vulnerable to radon exposure.
        4,000원
        13.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper proposes a solution to the out-of band oscillation signal and in-band low transmitter power output that occurrs during the low-temperature operation test for the new mine detector GPR signal transmission and reception module. Tests were performed by applying the optimal values of capacitors and inductors through circuit analysis simulation under the limited space, as a result, it was confirmed that the gain and return loss were improved at all-band thereby preventing oscillation signal and low transmitter power output.
        4,000원
        14.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        of actual and suspicious black-ice cases that occurred during the last 10 years in the Republic of Korea. METHODS : Based on literature review, meteorological observation data associated with black-ice formation are selected: wind speed, air temperature (T), dew point temperature (Td), and relative humidity, to set minimum or maximum threshold values based on the normal distribution of each variable. In addition, weights are assigned based on the relationship among the variables to calculate the probability of occurrence. RESULTS : The threshold values are calculated using the average and standard deviation, resulting in 7.65 °C, 56.63%, 2.99 ms-1 for T-Td, relative humidity, and wind speed, respectively. Whereas the threshold value of T-Td and wind speed is set to the maximum threshold, that of the relative humidity is set to the minimum threshold value. These threshold values are applied to the diagnosis algorithm of black-ice formation, including a 1-h accumulated precipitation. CONCLUSIONS : The algorithm is expected to be utilized as a research methodology for diagnosing suspected cases of black ice.
        4,000원
        15.
        2021.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        가교된 단분산 폴리스티렌 비드를 유화 중합과 분산 중합으로 합성하였다. 가교된 폴리스티렌 비드를 자일렌과 iron pentacarbonyl로 팽윤시킨 후 옥틸 에테르와 함께 환류하여 iron pentacarbonyl을 산화철로 변환시켰다. 산화철의 화학 안정성을 향상시키기 위해 산화철을 포함하는 폴리스티렌 비드를 실리카로 코팅하였다. 소결로 폴리스티렌 비드를 제거하여 산화철을 포함하는 중공 실리카 비드를 얻었다. 전체 합성 과정에서 모든 비드의 크기와 형태는 균일하게 유지되었고, 산화철을 포함하는 중공 실리카 입자는 강한 자성을 보였다.
        4,000원
        18.
        2020.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AZO thin films are grown on a p-Si(111) substrate by RF magnetron sputtering. The characteristics of various thicknesses and heat treatment conditions are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Hall effect and room-temperature photoluminescence (PL) measurements. The substrate temperature and the RF power during growth are kept constant at 400 ℃ and 200 W, respectively. AZO films are grown with a preferred orientation along the c-axis. As the thickness and the heat treatment temperature increases, the length of the c-axis decreases as Al3+ ions of relatively small ion radius are substituted for Zn2+ ions. At room temperature, the PL spectrum is separated into an NBE emission peak around 3.2 eV and a violet regions peak around 2.95 eV with increasing thickness, and the PL emission peak of 300 nm is red-shifted with increasing annealing temperature. In the XPS measurement, the peak intensity of Al2p and Oll increases with increasing annealing temperature. The AZO thin film of 100 nm thickness shows values of 6.5 × 1019 cm−3 of carrier concentration, 8.4 cm−2/V·s of mobility and 1.2 × 10−2 Ω·cm electrical resistivity. As the thickness of the thin film increases, the carrier concentration and the mobility increase, resulting in the decrease of resistivity. With the carrier concentration, mobility decreases when the heat treatment temperature increases more than 500 ℃.
        4,000원
        19.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        EMI(Electro Magnetic Interference) is a very important factor to consider in electronic equipment. For EMI coating, it is applied to the sputtering electronic equipment housing made by PEEK. The question arises that there may be physical changes in the PEEK material due to heat generated during sputtering. During sputtering inside the chamber, the degree of temperature due to the heat was measured indirectly, and characteristics such as bending capacity, tensile strength, impact strength, flexural strength were measured to understand physical changes. Tensile strength and the flexural strength increased by 14.5 to 18 compared to the base group. And the impact strength of the un-notched specimens was increased. Overall, there has been no change in the physical properties of PEEK due to heat generated during sputtering deposition.
        4,000원
        20.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구에서는 농림어업총조사 자료를 활용하여 읍·면단위 과소화비율에 영향을 미치는 요인들을 분석함에 있어서 농촌생활서비스를 중심으로 분석결과를 요약하면 다음과 같다. 첫째, 커널밀도함수를 이용한 분석을 통하여 2010년 읍·면별 과소화비율 분포가 2015년에 비해 넓게 분포되어 있음을 알 수 있다. 둘째, 농촌생활서비스 요인과 읍·면별 과소화비율 간에 정의 상관관계가 존재하는 것을 확인할 수 있었다, 셋째, 기초교육서비스, 문화서비스 및 복지서비스를 받기 위한 이동거리 증가가 과소화비율 증가를 유발하는 것을 알 수 있었다.
        4,000원
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