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        검색결과 29

        1.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sensory evaluation of shucking pressure, pressure holding time, seeding method, difference in full shucking rate in the aquaculture area and shucking oyster was performed using an ultra-high pressure oyster shucking machine. The reaching time for each target pressure is 2.2-2.4 MPa/sec in the range of 180 MPa to 240 MPa. had a rate of pressure rise. There was a difference of 0.5-1.7℃ in the range of 24-27℃ in the seawater temperature before and after the pressure treatment inside the pressure vessel, but there was no specific increase or decrease in seawater temperature. When only the shucking pressure is increased without the pressure holding time, the critical shucking pressure at which the oyster shell is opened and the flesh is peeled in the range of 200 to 220 MPa. When the critical shucking pressure is reached, the oyster sample in the closed vessel is expected to be shucked by about 40%. If there is no pressure holding time when judged only by full shucking, an increase in pressure of about 1.5 MPa is required to further shuck 3% of the oyster population. The oyster samples cultivated in the south coast of Korea were subject to full shucking under the conditions of 220 MPa shucking pressure and two minutes (120 seconds) of pressure holding time, and the difference in the pressure of the oysters according to the oyster seeding method and the farming area was minute. Finally, the condition of 220 MPa of shucking pressure and three minutes of pressure holding time was the best at 1.52 when the result of the sensory evaluation performed manually was set to 1.0. Next was 1.4 under the conditions of 220 MPa of shucking pressure and one minute of pressure holding time (60 seconds), and 1.3 under the condition of 220 MPa and two minutes of pressure holding time (120 seconds). Therefore, it is considered that the most desirable shucking conditions, considering the efficiency and sensory evaluation results, are the conditions of 220 MPa shucking pressure and two to three minutes of pressure holding time.
        4,000원
        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Owing to industrial development, the occurrence of continuous environmental damage such as abnormal weather is accelerating because of a rapid increase in carbon emissions. Therefore, various efforts are expended worldwide to realize a low-carbon ecofriendly society. In the construction industry, various efforts have been realized to reduce environmental pollution such as greenhouse gas emissions, for example by introducing eco-friendly materials and reducing industrial waste. In this study, an asphalt pavement technology that can reduce production and construction temperatures by more than 60 °C is developed to reduce the amount of carbon generated in the asphalt industry. METHODS : The performance of a half-warm asphalt binder developed using thermoplastic elastomers and low-temperature additives was assessed. In addition, the change in the quality of a mixture due to the use of the half-warm asphalt binder was evaluated. RESULTS : As the amount of thermoplastic elastomer used increases, the performance grade of the asphalt binder increases as well. When 3% or more of the elastomer is incorporated, the target performance grade of the asphalt binder is satisfied. In addition, by incorporating the thermoplastic elastomer and a low-temperature additive, the overall moisture and rutting resistance increased even at relatively low production and compaction temperatures. CONCLUSIONS : Additional measures to stabilize quality and improve economic feasibility will present a new paradigm for investigations into eco-friendly asphalt concrete pavements.
        4,000원
        3.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electrochemical water splitting is an important process for next generation of eco-friendly energy systems. The oxygen evolution reaction (OER), which occurs at an anode during the process, requires efficient electrocatalysts to reduce activation energies. Although Ru- or Ir-containing materials show excellent electrocatalytic activities, their high cost is a critical drawback. Consequently, the development of efficient electrocatalysts composed of low-cost metal components is a great challenge. In this study, we develop a new route to produce a hybrid material (Fe–NC) containing Fe3C particles dispersed on the surface of N-doped carbon (NC) materials by heat treatment of a mixture of urea and Fe(II)Cl2(H2O)4. Microscopic analyses prove that the Fe3C particles are placed on the surfaces of thin NC materials. Additionally, various characterizations reveal that the particles contain Fe3C structure. Fe–NC shows good electrocatalytic properties with onset and overpotentials of 1.57 V and 545 mV, respectively, for OER in KOH electrolyte. This study suggests the possibility of the use of Fe3C- based composites as OER electrocatalysts.
        4,000원
        6.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, for the treatment efficiency of the IGF process for the treatment of produced water (PW) discharged from the oil sands plant, the bench-scale oil sands plant PWT package was designed, manufactured and evaluated to verify the efficiency of the process. The microbubble generation efficiency and microbubble size change according to the circulation pump pressure were observed, and the correlation between influent concentration and temperature, residence time and oil-water separation performance was analyzed.
        4,000원
        8.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oxygen evolution reaction (OER) is an essential step at an anode in electrochemical water-splitting process and requires efficient electrocatalysts to reduce overpotentials. Although precious metal-based materials, such as RuO2, IrO2 and their hybrids with other components, performed excellently as OER electrocatalysts, their high cost has limited practical applications. Consequently, earth-abundant metal components including Fe, Co, and Ni have been investigated as alternatives. In this work, the hybridization of Ni-containing species with conductive carbon-based materials was used to prevent aggregation of active species and improve electrochemical catalytic performance. A new hybrid material composed of NiO nanoparticles and N-doped carbon materials was prepared. The NiO particles with a narrow size distribution were well dispersed on the surface of carbon-based materials. The hybrid showed improved electrocatalytic performance for OER than single components of NiO and N-doped carbon materials.
        4,000원
        9.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although somatic cell nuclear transfer (SCNT)-derived embryonic stem cells (ESCs) in pigs have great potential, their use is limited because the establishment efficiency of ESCs is extremely low. Accordingly, we tried to develop in-vitro culture system stimulating production of SCNT blastocysts with high performance in the colony formation and formation of colonies derived from SCNT blastocysts for enhancing production efficiency of porcine ESCs. For these, SCNT blastocysts produced in various types of embryo culture medium were cultured in different ESC culture medium and optimal culture medium was determined by comparing colony formation efficiency. As the results, ICM of porcine SCNT blastocysts produced through sequential culture of porcine SCNT embryos in the modified porcine zygote medium (PZM)-5 and the PZM-5F showed the best formation efficiency of colonies in α-MEM-based medium. In conclusion, appropriate combination of the embryo culture medium and ESC culture medium will greatly contribute to successful establishment of ESCs derived from SCNT embryos.
        4,000원
        10.
        2018.05 구독 인증기관·개인회원 무료
        In this research, the applicability of modified fouling index (MFI) on ultrapure water (UPW) production system was assessed to predict performance of reverse osmosis (RO) process. The practical study on MFI-UF was first performed at a pilot-scale UPW plant (Hwaseong-si, Gyeonggi-do, Korea), monitoring water quality parameters (i.e., conductivity, turbidity and TOC) as well as MFI-UF of pretreatment stage for 10 months. While water quality parameters were maintained in a stable manner, the MFI-UF was fluctuated implying the different propensity of RO influent. The increment of fouling potential was intimately related with RO performance, the aggravation of permeate quality. The sensitivity of MFI-UF was also verified by evaluating the fouling potential of reclaimed water in UPW production system.
        11.
        2018.05 구독 인증기관·개인회원 무료
        수소를 연료로 사용하는 PEMFC는 고효율⋅출력밀도를 나타내며, 짧은 시동시간, 우수한 응답특성에 따라 현지설치형 발전기술로 사용되며, 이를 위한 고효율 연료처리장치가 필수적이다. SMR반응은 연료당 고회수율을 때문에 경제성이 우수하며, 전환율 확보를 위해 700°C, 20 bar 이상의 운전조건에서 수행되며, WGS, PSA의 후단공정을 통해 수소를 생산한다. 분리막 개질기를 이용한 SMR반응은 분리막이 수소를 제거함에 따라 반응효율 증진, 공정온도 저감, 후단공정 배제를 할 수 있어 공정구성 및 경제성이 우수하다. 본 연구에서는 팔라듐분리막 개질기를 사용하여 550°C, 5 bar에서 SMR반응을 통해 수소를 생산하였으며, 개질된 가스의 CO 농도를 최소화하여 고온 PEMFC용 연료처리장치를 개발하였다.
        12.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is necessary to develop a mobile water production system in order to provide stable water supply in case of disasters such as floods or earthquakes. In this study, we developed a modular mobile water production system capable of producing water for various uses such as domestic water and drinking water while improving applicability in various raw water sources. The water production system consists of three stages of filtration (sand filtration - activated carbon filtration - pressure filtration) to produce domestic water and an additional reverse osmosis process to produce drinking water. In laboratory and field experiments, the domestic water production system showed excellent treatment efficiency for particulate matter, but showed limitations in the treatment of dissolved substances such as dissolved organic matter. In addition, ultraviolet irradiation was considered as additional disinfection step, because it does not form precipitates of manganese oxides after disinfection. Reverse osmosis process was added to increase the removal efficiency of dissolved substances and the treated water satisfied drinking water quality standards. Fluorescence analysis of dissolved organic matter showed that the fulvic acid-like substances in raw water was successfully removed in the reverse osmosis process. The mobile water production system developed in this study is expected to be used not only in water supply in case of disaster, but also widely used in islands and rural area.
        4,200원
        13.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is to compare the effect of estrus synchronization and embryo transfer between Korean and Mongolian cattle. Embryos were collected from 9 donors housed in Asan city in South Chungcheong Province, South Korea. Embryos were collected 9 donors from Khushaat sum, Selenge province and Bayanchandmani sum, Tov province in Mongolia. Follicle Stimulating Hormone (FSH), Controlled Internal Drug Release (CIDR) and Prostaglandin (PG) were used for superovulation. Subsequently, Artificial Insemination (AI) was done for donor cow and embryo was collected after 7 and 8 days. Collected embryos were compared between Mongolian and Korean cattle. Finally, good quality and fresh embryos were transferred to 50 and 22 recipients of cows in Korea and Mongolia respectively. The findings show that Korean native cattle each donor cow produced on an average 16.9 embryos and, 10.9 embryos were found transferable. But in case of Mongolia the average production of embryos per donor cow was 8.6 embryos and, 6.2 embryos were found transferable. Embryo collection after 7 and 8 days was not difference in embryo production in Korea. But, in Mongolia embryo production after 8 days was found more efficient than the 7 days. Korean native recipient's cows (74.6%) and Mongolian recipient's cows (71.0%) respectively were found transferable ovarian stage. The result suggested that efficiency of embryo production from the superovulation method treated of Korean cow were higher than the Mongolian cow. The pregnancy rate of Korea native cattle was 72%, which was about 10% higher than that of Mongolia cattle.
        4,000원
        14.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to determine the optimal supplementation level of beta-mannanase in the diet of laying hens. A total of 320 Hy-Line Brown layers (80 weeks of age) were assigned randomly into four groups on the basis of laying performance. Each treatment had eight replicates with 10 birds each (80 birds per treatment). Two hens were caged individually. Treatments were basal diet supplemented with 0 (control), 0.04, 0.08, and 0.16% beta-mannanase during the nine-week feeding period. Laying hens fed diets supplemented with increasing levels of beta-mannanase had increased (linear, p<0.05) overall egg production and egg mass. In addition, these hens had greater retention of dry matter, crude protein, gross energy, calcium, and mannan (linear, p<0.05). Dietary beta-mannanase treatments had no effect on blood metabolites such as total carbohydrate, triglycerides, glucose, total protein, and blood urea nitrogen, or excreted ammonia nitrogen and volatile fatty acids. The results obtained in present study indicate that dietary supplementation of beta-mannanase has the potential for improving the performance of laying hens. The optimal supplementation level is 0.04% beta-mannanase in the diet.
        4,000원
        16.
        2015.09 구독 인증기관 무료, 개인회원 유료
        본 연구는 시설원예 작물 재배 농가들을 대상으로 응답자들의 항목별 선호도를 분석하고, 농업현장에서 농민들이 체감하는 원예단지에 대한 만족도와 문제점을 파악하고 평가하고자 하였다. 분석 대상은 크게 생산관련 소모품 공동구입, 온실시설 기자재 공동구입, 공동 육묘 생산, 공동 냉난방시설 사용, 공동출하, 토양 검사 및 인증제도를 포함하는 공동 활동부분과 생산기술정보, 온실시설관리정보, 유통관련정보, 생산기술교육, 온실시설관리교육, 유통관련교육을 포함하는 정보교류 및 교육부분으로 나누었다. 공동활동 부분의 IPA분석결과 소모품 공동구입, 기자재 공동구입, 공동출하 항목이 중요도와 만족도가 모두 높아 지속적인 유지가 필요하며, 공동육묘 생산, 공동냉난방 시설 등 2개 항목은 중요도와 만족도가 모두 낮아 우선순위를 낮추어도 될 것으로 판단된다. 소모품 및 기자재 공동구입에 대한 단지별 생산자 니즈를 파악하고, 원예전문생산단지가 수출집중형인 경우에는 공동출하 체계를 적극 활용해 수출대상국별 경쟁력 있는 교섭권을 더욱 강화해 나가야 할 것이다. 한편, 육묘장과 냉난방시설의 경우, 정부지원을 받아 시설을 소유하고 있는 비율이 높기 때문에 중요도-만족도가 낮은 것으로 판단된다. 그러나 CO2 저감을 위한 환경친화적 신재생 에너지의 활용 및 지속가능한 농업의 관점에서 고찰해보면, 에너지 이용 효율성 제고 및 환경 친화적 원예단지 조성이 중요한 부분이라는 것을 인지해야 할 것이다. 또한, 토양 검증 및 인증 항목은 중요도에 비해 만족도가 높아 과잉관리가 개선될 필요성이 있는 것으로 나타났다. 이러한 결과는 원예전문생산단지 평가 지표에서 가점을 주는 평가항목들이기 때문에 이미 잘 관리가 되고 있는 것으로 설명할 수 있다. 정보교류 및 교육부문의 IPA분석결과 가장 집중적으로 관리되어야 할 요인으로 생산기술 교육이었으며, 원예전문단지교육을 실시하기 위해서는 생산기술 교육을 타 교육(온실관리 및 유통관련 교육) 보다 집중적으로 실시해야할 부분으로 평가할 수 있다. 생산기술 정보, 온실시설 관리정보, 유통관련 정보는 중요도와 만족도가 모두 높아 지속적으로 잘 유지해야 할 필요가 있는 요인들이다. 다양한 정보에 대한 응답자들의 중요도와 만족도가 높기 때문에, 농가들의 적극적인 정보 교류를 활성화 시키는 방안을 제시할 수 있을 것이다. 예를 들면, 구성원들의 정보교류 어플리케이션, SNS 활동 혹은 홈페이지 활용, 공식적인 정기모임 및 정보교류 회의를 위한 협의체를 구성 등을 들 수 있겠다. 온실관리 교육, 유통관련 교육의 2개 요인에 대해서는 우선순위를 낮추어도 좋은 것으로 판단된다. 마지막으로 생산성 향상 및 시설원예의 경쟁력 강화를 위해 정부 주도의 시설원예단지 규모는 더욱 확대될 것이므로, 본 연구의 결과가 원예전문생산단지의 운영에 효율적으로 적용되기를 기대한다.
        4,000원
        17.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As a result of an analysis of a damper system, a solution to a fire damper is developed using the continuity equation of damper control and orthogonal array. The fire damping device is made with a CAE software. Additionally, new H-120 grade fire damper is designed for the optimal offshore structure. This device will soon be tested on an actual offshore structure. An optimized fire temper is finally achieved using an orthogonal array. Using the result of present study will provide an environment friendly fire damper for offshore plants by choosing the optimum fire damper conditions
        4,000원
        18.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기업의 혁신전략이 특허생산 및 기업의 기술변화와 신제품개발에 미치는 영향을 분석함으로써 기업의 기술성과를 증대시키는 데 필요한 혁신전략을 도출하고자 하였다. 사용자료는 한국직업능력개발원의 「인적자본기업패널조사」(HCCP)의 1~4차년도 자료와 한국신용평가원의 기업재무자료, 특허청의 기업별 특허출원자료를 결합한 자료이다. 특허생산함수는 영과잉음이항회귀모형(ZINB)을 사용하여 추정하였다. 기업의 기술성과 결정요인은 특허의 내생성을 고려하여 2단계 추정방법을 사용하였고, 2단계 회귀식은 순위로짓모형을 사용하였다. 분석결과, 기업의 혁신전략이 특허생산 및 기업의 기술변화와 신제품개발에 중요한 영향을 미치는 것을 확인할 수 있었다. 첫째, 특허생산에서는 기업의 연구개발투자와 인적자원이 중요한 투입요소로 나타났다. R&D집약도가 높을수록 특허생산이 활발하게 이루어지되 한계생산은 체감하였고, 기업이 보유하고 있는 특허스톡이 많을수록 신규특허의 생산이 활발하였다. 기업의 인적자원수준이 높고 인적자원투자가 많을수록 특허생산이 활발하였고, 기업이 시장선도전략이나 빠른 추종자전략을 추구할 때 안정형 전략을 구사하는 기업에 비해 특허생산이 많았다. 둘째, 기업의 기술성과 결정요인으로는 인적자원의 역할이 중요하였고, R&D집약도는 대기업의 신제품개발에 유의한 영향을 미쳤다. 시장선도전략이나 빠른 추종자전략을 택한 기업의 기술성과가 안정형 전략의 기업보다 높았다. 특허생산이 활발한 기업일수록 기술성과가 높으나, 이는 상당부분 특허의 내생성에 기인한다. 본 연구의 분석결과는 특허의 생산뿐 아니라 특허와 신제품개발과 같은 기술성과와의 연계성을 높이는 전략이 필요하며, 기업특성에 따른 차별화 전략이 필요하다는 것을 시사한다.
        6,600원
        19.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper analyzed twenty-six production-related KPI(Key Performance indicator) factors of business diagnosis, such as personnel, equipment, materials, operations and quality affecting company business competition to 186 small machinery manufacturers in 2010. Also, we explained the concept of Business Positioning and divided research subjects into four Business Positioning Groups formed break-even point ratio & fixed cost ratio to sales and then we compared between the 4 groups using Logistic Regression analysis by SAS statistical software package. The objective of this study is two-fold. The first is to find out production-related KPI factor of superior Business Positioning Group. The second is to suggest improvement ways for small manufacturers in order to get better profitable Business Positioning.
        4,000원
        20.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 양질 조사료의 급여가 한우비육우의 사양성적, 육생산성 및 육질에 미치는 효과를 메타분석기법을 이용하여 분석하였다. 효과분석은 국내에서 수행된 논문들을 대상으로 총 5편의 연구논문들을 인용하였다. 양질조사료를 급여한 시험구를 처리구로 하고 볏짚을 급여한 시험구를 대조구로하여 처리구 결과와 대조구 결과의 평균차를 이용하여 효과의크기를 분석하였고, 요약효과는 임의효과모형을 이용하여 산출하였다. 그 결과, 사양성적에대한 정의효과는 사료섭취량, 일당증체량, 종료체중 및 사료효율 모두에서 나타났으며, 유의성은 일당 증체량에서만 발견되었다. 육생산량에 대한 정의효과는 도체중, 배측최장근 면적및 생산성 지수에서 나타났고, 등지방두께에서는 부의효과가 나타났다. 유의성은 도체중과배최장근 면적에서만 나타났다. 육질에 대한정의효과는 marbling score와 지방색에서 정의효과가 나타났으며, 육색은 부의효과가 나타났으나 유의적 효과는 발견되지 않았다.
        4,000원
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