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      검색결과 2,756

      1.
      2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
      Microalgae are efficient fatty acid producers owing to their high photosynthetic activities. They can act as sources of biofuel, feed, and various bioactive compounds. This study aimed to determine optimal culture conditions, including culture medium, temperature, and light intensity, to enhance the biomass and fatty acid content of the indigenous freshwater microalga, Tetradesmus obliquus. Evaluation using a high-throughput photobioreactor revealed that the optimal culture temperature and light intensity were 25°C and 300 μmol m-2 s-1, respectively. Additionally, we optimized components (N, P, and Mg) of the BG-11 medium to enhance the microalgal biomass. Modified BG-11 medium increased the T. obliquus biomass by 37% compared to the standard BG-11 medium. Subsequently, the culture medium was replaced with N- and P-depleted media to determine the abiotic stress factor that could increase the cellular fatty acid content. Notably, fatty acid content was significantly increased from 8.5% up to 14.6% on day 7 of culture in N-deficient (N-P+ and N-P-) media. Sequential optimization effectively increased the biomass by 83% and fatty acid content by >76% in T. obliquus. Our optimization method can be used to enhance the biomass and fatty acid contents of various other microalgae.
      4,200원
      2.
      2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
      Cool-season grasses are currently widely used in South Korea, but their productivity and quality may decline due to global warming associated with climate change. Warm-season grasses have shown greater adaptability to heat stress and drought conditions, making them potential alternatives for summer pasture establishment in central and southern Korea. This study aimed to compare the growth characteristics, productivity, and forage value of warm-season grasses bermudagrass and crabgrass for pasture establishment in the central region of South Korea. The experiment was conducted from May 2023 to October 2024 at the National Institute of Animal Science, Cheonan, South Korea. Crabgrass exhibited superior initial establishment and faster growth rates, whereas bermudagrass had poor initial growth, placing it at a competitive disadvantage against weeds. However, after the first cutting, bermudagrass successfully established itself and maintained a stable botanical composition. The annual dry matter productivity of crabgrass (8,586 kg/ha in 2023 and 12,013 kg/ha in 2024) was 32.62% and 40.18% higher, respectively, than that of bermudagrass (5,785 kg/ha in 2023 and 8,570 kg/ha in 2024). In forage value, crabgrass tended to show higher feed value at the initial harvest, while bermudagrass showed higher quality at the later harvests. In conclusion, these results suggest that both crabgrass and bermudagrass have potential for pasture establishment, with carbgrass being more suitable for short-term due to its rapid growth and high productivity, and bermudagrass being more appropriate for long-term due to its stable productivity in regions where overwintering in possible.
      4,000원
      3.
      2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
      본 연구에서는 경남지역 시군별 농림어업의 성장 추이에 대한 분석을 두 가지 측면에서 접근하였다. 첫째, 경남지역의 18개 시군을 과거 20년 동안의 농림어업생산액 성장률과 현재의 수준을 기준으로 비교하여 지역 유형화를 시도하였다. 이는 각 시군을 농림어업의 성장에 관한 정태적 및 동태적 관점에서 유형화함으로써, 각 시군이 상대적으로 어떠한 위치에 있는가를 객관적으로 파악할 수 있게 해줄 것이다. 둘째, 변이-할당분석을 통해 각 시군의 과거 20년 동안의 농림어업 성장을 3개의 요인으로 구분하여 분석하였다. 이를 통해 각 시군의 농림어업 성장이 어떤 요인에 의해 결정되었는가를 파악함으로써, 향후 농림어업 성장을 더욱 활성화하기 위한 전략 설정과 정책 수립에 시사점을 제공해 줄 수 있을 것이다.
      4,000원
      4.
      2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
      본 연구는 맹종죽(Phyllostachys edulis) 부산물의 고부가가치 활용을 위한 기초연구로, 맹종죽림 조사 및 소각처리를 통한 죽회 생산 기술을 개발하고자 하였다. 맹종죽림 현장에서의 죽간 벌채 후 남은 상층 부산물(잎, 잔가지, 끝대)과 수년간 방치된 하층 부산물의 바이오매스 총량을 파악한 결과, 입죽 상태의 맹종죽을 벌채할 경우, 활용될 죽간의 중량비는 56.6%, 죽림 내에 방치되는 상층 부산물의 중량비는 43.3%로 나타났다. 방치됐던 하층 부산물은 ha당 약 26톤이 잔존해 있었다. 한편, 부산물을 죽회로 활용하기 위해 소형 소각로 및 대형 무연소각로를 이용한 소각처리를 수행하였다. 현장에 설치된 소각로에서의 조사 결과, 소형소각로(화실, 57.2 ㎥)는 1시간에 10 kg, 1일 최대 80 kg을 소각하는 반면, 대형 무연소각로 (화실, 791.4 ㎥)는 1시간에 70 kg, 1일 최대 560 kg을 소각하여 약 7배의 효율을 보였다. 2차 회화 과정을 통해 얻은 순수 죽회의 수율은 약 84%였으며, 칼륨(80,000 ppm↑), 칼슘(50,000 ppm↑), 인(20,000 ppm↑), 마그네슘(20,000 ppm↑), 망간(10,000 ppm↑), 철(10,000 ppm↑) 등 다양한 무기원소가 함유되어 있었다. 본 연구는 대나무 벌채 현장에서 수행된 실험을 바탕으로, 맹종죽림의 지속 가능한 경영과 새로운 부산물 활용 방안에 대한 제시로 큰 의의가 있을 것으로 판단된다.
      4,000원
      5.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      Background: This study was conducted to increase meat production by 30% compared to the present by selecting a giant cow over 1,000 kg and applying biotechnologies. Methods: After OPU from 1,100 kg of giant cow, the calves were produced in Hanwoo surrogate mothers. Among 23 calves six male heads were selected, three heads of them were chosen as candidate sires, and the rest three heads were raised for 30 months for performance test. The semen of three candidate sires from the age of 22 months were collected and frozen, and the calves were produced by artificial insemination. The calf was raised to the age of 30 to 33 months and performed a progeny test. Results: The average birth weight of 23 calves born by transferring giant cow-derived embryos was 42.8 kg, and the average weight of carcass from three bulls was 615.3 kg in the performance test. In the progeny test, the average birth weight of calves born after artificial insemination of semen from giant cow-derived candidate sires was 41 kg, and the average weight of carcass after raised to the age of 30 to 33 months was 562.7 kg. As a result of performance and progeny tests, it is 148 and 96 kg higher in giant cow-derived beef cattle than the average carcass (467 kg) from general Hanwoo cattle, respectively. Conclusions: This study will have laid a great foundation for the future improvement of the Korean beef industry.
      4,000원
      6.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      꼬리말발도리(Deutzia paniculata Nakai)와 가침박달 (Exochorda serratifolia S.Moore)은 각각 5~6월과 4~5월에 흰색 꽃이 피는 화목관목으로 한국의 희귀식물이며, 관상가치가 높아 원예용으로 개발할 가치가 있다. 본 연구에서는 꼬리말발 도리와 가침박달의 종자를 이용한 번식체계를 확립하고자 플러 그 육묘에서 플러그 트레이의 셀 크기, 배지조성, 시비수준에 따른 유묘의 생육을 조사하였다. 꼬리말발도리는 플러그 트레이 의 셀 크기가 작아질수록 유묘의 생육이 불량하였고, 105구의 셀 크기에서 초장, 엽장과 엽폭, 줄기와 뿌리의 생체중 등 생육 이 가장 양호하였다. 또한 배지의 조성은 피트모스와 펄라이트 를 20:80로 혼합한 처리에서 줄기와 뿌리의 생육이 가장 우수하 였고, 펄라이트 단용인 0:100 처리에서 유묘의 생육이 가장 불 량하였다. 가침박달은 피트모스와 펄라이트를 100:0과 75:25 로 혼합한 배지에서 유묘의 생육이 가장 좋았고, 펄라이트 단 용인 0:100 배지에서 유묘의 줄기뿐만 아니라 뿌리의 생육 도 가장 불량하였다. 그리고, 육묘 기간동안 시비수준이 증가 함에 따라 유묘의 줄기 생육이 양호하였으며, 엽록소의 함량도 증가하였다. 따라서 가침박달은 플러그 트레이 당 Hyponex (N:P:K=20:20:20) 6.24.g을 관주하는 것이 고품질 묘를 생산 하는데 가장 효과적이었다. 따라서 꼬리말발도리는 105공 플러 그 트레이에 피트모스와 펄라이트의 20:80 비율의 배지를 사용 하는 것이, 가침박달은 피트모스와 펄라이트의 100:0과 75:25 비율의 배지에서 육묘기간동안 Hyponex 6.24g를 시비하는 것이 유묘 생육에 가장 적합하였다.
      4,000원
      7.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      이 연구는 인공지능(AI)이 문화콘텐츠와 미디어 산업에 미치는 영향을 다각적으로 분석하고, AI의 창의 적 생산, 미디어 소비 변화, 윤리적·사회적 쟁점에 대해 논의하였다. 그리고 AI가 콘텐츠 제작에서 창의성과 효율성을 높이며, 창작자와의 협력을 통해 새로운 형태의 콘텐츠 창출을 가능하게 한다는 점을 확인하였다. 또한 AI 기반 추천 시스템을 통해 개인화된 미디어 소비 경험이 제공됨으로써 사용자 만족도와 소비 지속 성이 강화된다는 사실을 밝혔다. 그러나 AI 도입은 저작권 문제, 알고리즘 편향성, 문화적 다양성 보존, 사회적 고용 변화 등 다양한 윤리적·사회적 과제도 야기하고 있다. 이를 해결하기 위해 법적, 기술적, 정책 적 접근이 필요하며, AI의 투명성과 공정성을 확보하는 것이 필수적임을 강조하였다. AI와 인간이 협력하 여 공정하고 신뢰할 수 있는 콘텐츠 제작을 지향할 때, AI는 문화콘텐츠와 미디어 산업의 발전에 이바지할 수 있을 것이다. 본 연구는 AI와 문화산업의 융합을 둘러싼 다양한 이슈를 종합적으로 검토함으로써 향후 지속 가능한 발전을 위한 방향성을 제시하고자 한다.
      6,000원
      8.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      본 연구에서는 자료포락분석(DEA) 기법을 이용하여 해양환경 요인의 영향을 받는 남해 주요 해역의 어업생산활동 효율성을 비교하고, 해양환경 재해요인이 효율성 변동에 어떠한 영향을 미치는지 분석하였다. 분석에는 남해 서부 여자만부터 동부 진해만 해역까 지 18개 해역을 업무구역으로 하는 12개 지구별 수협의 10년간(2013-2022년) 계통출하 생산자료를 사용하였다. 분석기간 동안 여수와 고흥 수협이 상대적으로 적은 생산자수와 어업비용을 투입하여 높은 생산량과 생산금액을 산출함으로써 높은 기술적 효율성을 달성하였으며, 멸치 생산금액과 김 생산량이 각각 높은 효율성의 기반으로 추정되었다. 평균 기술적 효율성은 2013년 49.3%에서 2022년 40.7%으로 감소 하였으며, 통영 수협이 96.4%에서 34.5%로 가장 크게 감소하였다. 삼천포 수협은 기술적 효율성 대비 규모 효율성이 가장 높아 생산기술 의 순수기술적인 비효율을 해결해야 하는 것으로 나타났다. 정태적 분석에서 기술적 효율성을 달성했던 여수와 고흥 수협의 경우, 5년 단 위의 Window-DEA 분석 결과 동태적인 비효율성이 존재하는 것을 확인하였다. 해양환경 재해요인의 경우, 진해만 해역의 수협과 여수 수 협의 어업생산 효율성이 연도별로 빈산소수괴 발생횟수와 유의한 부(-)의 상관관계를 나타내었다.
      4,000원
      9.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      The objective of the present study was to investigate the effects of different red seaweeds on in vitro rumen fermentation characteristics and methane gas production. Five species of red seaweed (Chrysymenia wrughtii Yamada, CW; Hypnea sp., Hypnea sp.; Chondria crassicaulis, CC; Gelidium vagum Okamurae, GV; Hypnea saidana Holmes, HS) were obtained from National Institute of Fisheries Science (NIFS) in South Korea. The collected red seaweeds were washed for 3 minutes, and then samples were freeze-dried and ground to a size of a 1 millimeter. The buffered ruminal fluid (50 mL) was incubated with substrates and seaweeds (5% of substrates) at 39℃ for 48 hours. Total gas production was lower than red seaweed treatments excluding the CW treatment (p<0.05; 63.25 mL). Methane production was the lowest in CC treatment (p<0.05; 9.93 mL/g of digestible dry matter). The rumen pH of the red seaweed treatments ranged from 5.98 to 6.08, which was significantly the lowest in the GV treatment (p<0.05; 5.98). There was no significant difference in the total VFA concentration, but propionate (27.53%) was significantly highest in the CW treatment, whereas acetate (53.14%), iso-valerate (3.52%), valerate (1.72%), and A:P ratio (1.93) were significantly lowest (p<0.05). In conclusion, among the five species of red seaweeds, Chondria crassicaulis reduced in vitro methane production without negative effects on dry matter digestibility. Future studies will be needed to determine the optimal inclusion level of Chondria crassicaulis as feed additive to reduce enteric methane production.
      4,000원
      10.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      This study aimed to investigate the effects of various washing pre-treatments of native Codium fragile as a feed additive on in vitro ruminal fermentation and CH4 production in ruminants. Seaweed was included at 0.5% dry matter (DM) based on the experimental feed (forage : concentrate = 3:7). Treatment groups were classified as follows: experimental feed (C), no washing (T1), washing at 0°C (T2), washing at 22°C (T3) and washing at 70°C (T4) each immersed for 6 minutes in distilled water. The pH consistently fell within the ruminal stability range. In vitro dry matter digestibility was significantly highest in T2, T3, T4 and C, T4 was the lowest at 48 h (p<0.05). NH3-N concentration was significantly highest in T4 at 48 h (p<0.05). Total gas production at 48 h was 19% lower in T4 compared to C (p<0.01). CH4 production (mL/g DM) at 48 h was lower in all treatment groups compared to C, with T3 showing a 31% reduction (p<0.01). Similarly, CH4 production (mL/g dry matter degradability, DMD) at 48 h was 39% lower for T3 compared to C (p<0.01). At 24 h, total VFA was significantly highest in T1 and T4 (p<0.05). The proportions of acetate was significantly highest in C and T3 was the lowest at 48 h (p<0.01). The proportions of propionate was significantly highest in T3 and C was the lowest at 48 h (p<0.01). The acetate to propionate ratio was singnificantly highest in C at 48 h (p<0.01). The proportions of butyrate at 24 h was lower for T3 compared to C (p<0.05). Therefore, this study confirms that Codium fragile can reduce CH4 production when used as a feed additive for ruminants and this effect is not significantly influenced by the washing pre-treatment. However, if washing process is necessary, washing at 22°C is the most appropriate method to remove foreign objects.
      4,300원
      11.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      The purpose of this study is to estimate the production function of the oliver flounder (Paralichthys olivaceus) aquaculture industry, analyze its efficiency, and provide implications for sustainable aquaculture. For this purpose, the SFA model was utilized. The results of this study are as follows. First, the coefficient values of labor wages and farm area are higher than other inputs. This suggests that the Korean oliver flounder aquaculture industry is labor-intensive. Second, disease management is highly influenced by management efficiency. The more frequently farms are disinfected and culled, the higher the management efficiency with culling having a greater impact on management efficiency. Finally, the cost inputs of high and low-efficiency fish farms were analyzed, and it is recommended that wages, electricity, drugs, and oxygen should be kept at a reasonable level rather than excessive. However, the higher the inputs for mortality removal and disease management, the higher the management efficiency. In other words, improving the farm environment is the most important to achieve sustainability and management efficiency of Korean oliver flounder farming.
      4,200원
      12.
      2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
      This study aimed to assess the global and domestic efforts regarding the reduction of environmental-impact-factor emissions in the production and construction processes of concrete pavements. By utilizing internationally commercialized programs, this study sought to calculate the environmental impact factors generated by specific domestic concrete-pavement projects and identify areas for improvement. This study evaluated the global and domestic efforts of environmental impact reduction by focusing on the production and construction of concrete pavements. This study calculated the environmental impact factors for five cases using internationally commercialized software. The analysis revealed that, during the production and construction of concrete pavements, Portland cement production is a dominant cause of global warming, smog, acidification, and non-carcinogenic factors, whereas aggregate production is a dominant cause of ozone depletion, eutrophication, carcinogenicity, respiratory issues, environmental toxicity, and fossil-fuel depletion. This study analyzed the environmental impact factors of material mix and process during concrete pavement production and construction using foreign life-cycle inventory (LCI) databases. The environmental impact of each input material was identified. In the future, if an LCI and life-cycle impact assessment (LCIA) database for domestic road pavement materials is established and analyzed based on the conditions presented in this study, it is expected to lay the foundation for the development of environmentally friendly materials.
      4,300원
      14.
      2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
      The economical manufacturing of high-quality graphene has been a significant challenge in its large-scale application. Previously, we used molten Sn and Cu as the heat-transfer agent to produce multilayer graphene on the surface of gas bubbles in a bubble column. However, element Sn and Cu have poor catalytic activity toward methane pyrolysis. To further improve the yield of graphene, we have added active Ni into Sn to construct a Sn–Ni alloy in this work. The results show that Sn–Ni alloy is much more active for methane pyrolysis, and thus more graphene is obtained. However, the graphene product is more defective and thicker because of the faster growth rate. By using 300 ml molten Sn–Ni alloy (70 mm height) and 500 sccm source gas ( CH4:Ar = 1:9), this approach produces graphene with a rate of 0.61 g/hr and a conversion rate of methane to carbon of 37.9% at 1250 ℃ and ambient pressure. The resulting graphene has an average atom layer number of 22, a crumpled structure and good electrical conductivity.
      4,000원
      15.
      2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
      With the development of photocatalytic hydrogen production technology, the effective transport of photogenerated carrier electrons is still one of the main factors affecting the performance of photocatalytic hydrogen evolution. In this work, graphdiyne was prepared by ball milling method. The CoMo-MOF with polyhedral structure was introduced into graphdiyne to construct S-scheme heterojunction to promote the efficient transfer of photogenerated carriers and enhanced hydrogen evolution activity. Graphdiyne is a new carbon material with adjustable band gap, which is synthesized from the hybrid of sp and sp2, and has excellent electrical conductivity. CoMo-MOF is a polyhedral structure that can provide more active sites and promote photocatalytic hydrogen evolution. The weak point of poor conductivity in CoMo-MOF has been successfully improved by combining CoMo-MOF with graphdiyne, and the migration rate of photogenerated carriers has been accelerated. The hydrogen evolution property of graphdiyne/CoMo-MOF is 300 μmol, which is 19.61 times that of graphdiyne and 9.03 times that of CoMo-MOF. Therefore, the construction of S-scheme heterojunction provides a transport channel for electron transfer and improves the efficiency of photogenerated carrier separation. This work provides a new train of thought of design to introduce MOFs materials into carbon materials for photocatalytic hydrogen evolution.
      4,600원
      16.
      2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
      Analyzing and diagnosing the causes of abnormal conditions through control logic processes at the plant site is critically important. When a process is halted, the steps for cause analysis and corrective action vary depending on the operator's experience and the specific characteristics of the process. Since it's often not feasible to keep the process stopped for an extended period, issues are sometimes resolved by forcibly restarting the PLC(Programmable Logic Controller). However, this can lead to the recurrence of the same error, which may negatively impact process operations. In particular, oil sands development is an uncharted area with anticipated environmental challenges. In this regard, an integrated system between control systems in the oil sands production plant was established to implement control logic, develop the HMI(Human-Machine Interface), and verify the user interface. This allowed for a better understanding of the equipment's operability.
      4,000원
      17.
      2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
      본 연구의 목적은 로봇 제작 프로그램이 초등 저학년의 사회성 향상에 미치는 영향을 알아보는 것이다. 연구 대상은 U시의 J교육원에서 또래관 계의 어려움을 경험하고 있는 초등학교 저학년을 대상으로 하였다. 아동 과 보호자의 동의를 받은 최종 20명을 실험집단 10명, 통제집단 10명으 로 구성하였다. 실험집단에게는 로봇 제작 프로그램을 주 2회(회기 당 60분) 총 12회기를 실시하였으며, 실험·통제집단 모두에게 프로그램 효 과성을 검증하기 위해 사회성 검사를 프로그램 전후로 실시하고, 프로그 램 종료 후 4주 뒤에 추후 검사를 통해 효과의 지속성을 확인하였다. 로 봇 제작 프로그램을 실시한 결과 실험집단의 사회성이 향상되었으며 프 로그램 종결 후에도 효과가 지속되는 것으로 나타났다. 따라서 로봇 제 작 프로그램으로 아동의 사회성 향상을 위한 다양한 연구와 교육 현장과 보건복지부의 지원 사업 중 아동의 정서 및 심리의 문제를 해결할 수 있 는 프로그램으로 활용 될 수 있을 것으로 기대한다.
      6,400원
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