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        검색결과 32

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Derive a road pavement design method using Geocells, aim to derive a road pavement design and construction method suitable for the characteristics of the Bangladesh region METHODS : To assess long-term performance during road construction in Southeast Asia using Geocells, field tests and numerical analysis are conducted to verify stability. RESULTS : A total of 12 displacement measurements were conducted during the field tests, confirming an average load of 15.75 kN and an average displacement of 0.542mm. Inverse analysis was performed to obtain the properties of Geocell combined with compacted soil. The numerical analysis results confirmed that the insertion of Geocell provides better stability compared to the case with only compacted soil. CONCLUSIONS : Based on field tests and numerical analysis, a road design plan suitable for the Southeast Asian environment was proposed. A preliminary test section was selected in the Comilla region of Bangladesh, and test construction has been completed. Subsequent evaluations of the structural performance by soil layer in the test construction area will be conducted to develop a Geocell road pavement method, taking into consideration the characteristics of the Bangladesh region.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study is aimed to economic analysis of the ferronickel slag pavement method carried out to suggest the necessity of developing ferronickel slag pavement technology. METHODS : A life cycle cost analysis of the application of the Ferronickel Slag pavement method and the cutting + overlay pavement method was performed to compare the economic indicators and greenhouse gas emissions for each pavement method. RESULTS : As a result of the analysis, regardless of the Ferronickel Slag mixing rate, if the common performance of the Ferronickel Slag pavement method is the same or superior to the existing pavement method, it is more economical than the existing pavement method. Furthermore, the lower the maintenance cost of the Ferronickel Slag pavement method, the higher the economic feasibility due to the high Ferronickel Slag mixing rate. Greenhouse gas emissions can be reduced from at least 9% to up to 53% through the application of the Ferronickel Slag pavement method, except for some scenario analysis results. CONCLUSIONS : This study provided that the Ferronickel Slag pavement method was superior to the existing pavement method in terms of economic and environmental aspects. Therefore, it was found that the objective justification of developing road pavement technology using Ferronickel Slag was secured.
        4,000원
        7.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Data on the crude protein requirements of elk doe are nonexistent and the data are essential for their management in Korea. Therefore, this study was conducted to evaluate the crude protein requirement for maintenance of elk doe. Three female elk deer were used in 3 × 3 Latin square design with three diets containing three levels of crude protein (CP) that contained low crude protein (approximately 12%), medium crude protein (15%), and high crude protein (18%). Each three elk doe trials included a 14-day preliminary period and a 5-day collection period. Crude protein intake was 4.83, 6.26, and 9.00 g/d for 12%, 15%, and 18% of CP level, respectively. Crude protein balances were 1.04, 1.41, and 4.14 for 12%, 15%, and 18% of CP level, respectively. The maintenance requirement for CP from the regression equation between CP intake and CP balance were 3.70 g/BW0.75.
        4,000원
        8.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to estimate the reduction in traffic noise in a double-layered specific porous pavement at roadsides based on variations in traffic volume and driving speed. METHODS : A statistical pass-by (SPB) method was employed in this study to measure noise. Variations in the following parameters were measured: running speed, heavy traffic percentage, and traffic volume. RESULTS : Quantitative analysis revealed that the double-layered porous pavement reduced noise levels by 9.16 dB(A) at a 95% confidence level at the sides of roads. CONCLUSIONS : As a countermeasure of traffic noise, porous pavement has been recommended. This research quantitatively proved that double-layered porous pavement can reduce traffic noise by more than 9.0 dB(A) at roadsides
        4,000원
        9.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The objective of this study is to evaluate and compare the stiffness characteristics and seasonal variation in surface deflections of block and asphalt pavements using the light weight deflectometer (LWD) and falling weight deflectometer (FWD). METHODS: LWD and FWD testing was conducted on block and asphalt pavement sections in a low-impact development facility, to evaluate the structural capacity and seasonal variation in asphalt pavements. To analyze the seasonal variation in stiffness characteristics, this testing was performed in October 2016, January 2017, and March 2017 in the same drop locations. RESULTS : It was found from that the average center deflections in the asphalt and block pavements were 218 ㎛ and 2974 ㎛, respectively. The center deflections measured using FWD testing in block pavement are 15 times those measured in asphalt pavement. It was also observed that LWD deflections in block pavements were decreased by approximately 65-90% as the air temperature dropped from 20 to 4℃. The degree of reduction in block pavement was significantly higher when compared with asphalt pavement, which showed a 25- 50% reduction in deflection. CONCLUSIONS: When using block pavements for roadways, the structural capacity of the pavement system should be considered during the design and construction stages. In block pavements, the use of low-quality material and insufficient compaction in the base and subgrade layers can induce a reduction in structural capacity, which would lead to the need for frequent repair work. A reinforcement underneath the block layer would be an appropriate measure for improving the structural support and extending the service life.
        4,000원
        10.
        2019.04 구독 인증기관·개인회원 무료
        Methyl bromide (MB) has been still routinely used in quarantine fumigation on imported citrus, although there had been issuing chronic inhalation toxicity to fumigators and related workers as well as phytotoxic damages after fumigation. Ethyl formate (EF), is the only option to replace MB in terms of its safety for consumers (food additive and naturally occurred) and worker with higher threshold level limit (TLV = 100 ppm). Its application technology also provide cost effectiveness, good commercial practice in terms of application time (< 10 min) for 40 ft container. The replacement of MB with EF is recommended not to fumigate with hazardous and phasing-out MB on imported oranges.
        11.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        가상현실이란 디지털로 표현된 가상 환경을 뜻하며 인터넷 쇼핑, 아바타 등 기본적으로 디지털 환경을 일컫는 단어이며, 최근에는 머리에 장착하는 디스플레이(HMD : Head Mounted Display)의 등장으로 사용자가 현실과 유사한 환경을 직접 경험하는 체험형 콘텐츠로서 의미를 확장했다. 현재 가상현실은 게임을 비롯한 힐링 콘텐츠, 관광, 군사 시뮬레이션 다양한 분야에서 주목받고 있으며 HMD의 보급 또한 활발하다. 사용자가 가상현실 콘텐츠를 체험하기 위해서는 몇 가지 제약이 발생하는데, 사용자의 시야가 차단되 현실공간감각이 상실된다. 따라서 기존에 사용되었던 입력장치인 키보드, 마우스 등의 사용에 어려움이 있으며 HMD를 개발하는 개발사들은 위의 문제를 해결하고자 가상현실 체험에 특화된 핸드트래킹 디바이스를 제공한다. 하지만 이 또한 상호작용, 이동, 제스처가 손에 집중되어있어 가상환경에 익숙하지 않은 이용자의 사용자 편의가 낮다. 본 논문은 이러한 이동의 문제를 아두이노를 통해 제작한 발 트레킹 디바이스로 이동을 분리시켜 해결하고자 하였다. IMU의 각속도계와 가속도계를 이용해 다리의 궤적을 측정하려 하였고, 이때 발생한 오차는 상보필터를 통해 해결하였다. 또한 기본적으로 발생하는 센싱-통신-연산 과정에서의 노이즈는 두가지 이동평균기법과 생략평균값을 이용해 안정화 시켰다. 사용자는 해당 장비와 Oculus Rift를 착용하고 Unity3d환경으로 구축된 실험환경에서 임무 수행 속도, 이동방향 오차율등을 측정해 기존 HMD컨트롤러와 본 논문에서 제시하는 컨트롤러를 비교 검증했다. 실험 결과 임무 수행 속도와 이동 오차율 모두에서 본 논문에서 제시하는 장치가 우수한 데이터를 제공하였다. 본 실험 결과를 토대로 이동조작 분리가 높은 접근성을 제공한다는 것을 확인하였다. 본 논문은 HMD 이동 컨트롤러를 포함한 이후 개발되는 다양한 사용자 제스처 인식 컨트롤러에도 적용 가능할것으로 보인다.
        4,000원
        12.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the aerospace field, Carbon/Cork composites have been used for rocket propulsion systems as a light weight structural component with a high bending stiffness and high thermal insulation properties. For the fabrication of a carbon composite with a heat insulation cork part, the bonding properties between them are very important to determine the service life of the Carbon/Cork composite structure. In this study, the changes in the interfacial adhesion and mechanical properties of Carbon/Cork composites under accelerated aging conditions were investigated. The accelerated aging experiments were performed with different temperatures and humidity conditions. The properties of the aged Carbon/Cork composites were evaluated mainly with the interfacial strength. Finally, the lifetime prediction of the Carbon/Cork composites was performed with the long-term property data under accelerated conditions.
        4,000원
        20.
        2011.10 구독 인증기관·개인회원 무료
        Urokinas type plasminogen activator (uPA) has been used as a therapeutic agent for treating human diseases such as thrombosis. Attempts to transgenically overexpress the uPA in animal bioreactors have been hampered due to side effects associated with this functional protein hormone on homeostasis. Recently, chicken has been emerged as a potential candidate for use as bioreactor to produce proteins of pharmaceutical importance. Since this species has low homology uPA sequence with mammals, we hypothesized that chicken could be used as a potential bioreactor for production of human uPA. In this study, using replication‐defective Murine Leukemia Virus (MLV)‐based retrovirus vectors encapsidated with Vesicular Stomatitis Virus G Glycoprotein (VSV‐G), we attempted to make transgenic chicken expressing human uPA (huPA). The recombinant retrovirus was injected beneath the blastoderm of non‐incubated chicken embryos (stage X, at laying). After 21 days of incubation (at hatching), all of the 38 living chicks that assayed, were found to express the vector‐encoded huPA gene in various organs and tissues, which was under the control of the Rous Sarcoma Virus (RSV) or Cytomegalovirus (CMV) promoter. Using specific primer set for huPA, PCR and RTPCR analyses of gDNA isolated from these samples demonstrated these chickens were transgenic for huPA. Furthermore, successful germ line transmission of huPA transgene was confirmed and next generation whole body huPA transgenic chickens were also produced. We also assayed huPA protein titer in blood (17.1 IU/ml) and eggs (4.4 IU/ml) of whole body huPA transgenic chicken. Thus, our results demonstrated that chicken could be used as bioreactors to produce huPA.
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