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        검색결과 1,153

        21.
        2023.10 구독 인증기관·개인회원 무료
        마늘은 백합과 알리움속에 속하는 작물로 약용, 양념채소로 많이 소비되어져 왔다. 마늘은 6월에 수확하여 1개월 간의 건조과정을 거치게 되는데 보통 장마기와 겹치게 되어 연평균 부패율은 5%이상으로 높다. 마늘의 저장중 병해충은 뿌리응애, 마늘혹응애, 마른썩음병 등으로 섭식에 따른 부패를 유발하며, 건조시기를 단축하고 효율적인 건조를 통하여 감모율을 줄이는 것이 중요하다. 마늘의 병해충 피해를 줄이기 위해 개발한 열풍 흡기식 건조장치를 포함하여 관행, 열풍 건조기, 흡기식 건조 등 4가지 방법으로 마늘을 건조하였으며, 방법별 건조소요 일수, 부패율 등을 조사하였다. 연구결과 열풍-흡기식 건조장치의 순환 공기의 온습도는 외기대비 7.8℃ 높았고, 28.6% 낮았으며, 건조 소요일수는 관행건조 대비 31% 수준으로 우수하였다. 또한 병해충 피해 양상은 관행 건조 대비 4.4%p낮아 건조 기간 및 정상품율이 관행 대비 우수하여, 관행 건조를 대체 가능할 것으로 생각된다.
        22.
        2023.10 구독 인증기관·개인회원 무료
        표면발현(surface-display system)은 세포 또는 바이러스 표면에 목적 단백질을 고정하여 발현시킴으로써 목적 단백질에 대하여 독립적인 공간 구조 및 생물학적 활성을 부여하는 단백질 공학 기술이다. 또한 이를 이용하여 높은 중화항체 유도 및 대량생산이 가능한 삼량체의 형태로 항원 단백질의 발현 또한 가능하다. BES(baculovirus expression system)에서의 표면발현 기술은 번역 후 수정과정 및 복잡한 구조의 다양한 단백질의 발현이 가능하기 에 다른 숙주 기반 시스템보다 효율적이라고 보고되고 있다. 그러나 목적 단백질 외의 다른 표면 단백질과 발현 공간에서의 경쟁으로 목적 단백질의 낮은 생산량이 큰 문제점으로 지적되고 있다. 따라서, 이러한 BES에서 표면 발현의 생산 효율을 증대시키기 위하여, 동일한 표면 공간에 대한 단백질 간의 발현 경쟁에 대해 실험적으로 확인 후, 그를 해결하기 위하여 표면발현에 최적인 목적 단백질 발현을 위한 프로모터 선발 실험을 수행하였다. 이를 통해 BES에서 표면발현에 의한 목적 단백질의 생산 효율을 증대시킬 수 있음을 확인하였다.
        23.
        2023.10 구독 인증기관·개인회원 무료
        양봉꿀벌은 한 마리 여왕벌을 중심으로 일벌 및 수벌들이 군집을 이루고 있는 사회성 곤충이다. 꿀벌은 여왕벌 이 깨어나면 처녀비행 (반경 2.4~7.4km )을 하여 공중에서 여러 마리의 수벌들과 교미를 한 후, 자신의 봉군 내부로 돌아와 평생을 살아가는 생태적 특성을 가지고 있다. 이와 같은 이유로 계통 증식 또는 품종 육종에서 외부의 오염원을 차단하기 위해서는 여왕벌과 수벌이 격리된 지역에서 교미가 이루어져야 한다. 본 연구는 여왕벌과 수벌이 격리될 수 있는 국내 도서지역을 중심으로 격리교미 연구를 2020년부터 2023년 봄부터 가을까지 수행하 였으며, 육종을 위한 격리교미의 효율성을 분석하고자 하였다. 도서지역은 전남 - 낙월도, 전북 - 위도, 왕등도, 식도에서 수행되었으며, 섬 크기, 경관 환경 요인, 교미 시기 등에 의해 격리교미의 성공률이 어떻게 변하는지를 확인하였다.
        26.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Efficient gene editing technology is needed for successful knock-in. Homologous recombination (HR) is a major double-strand break repair pathway that can be utilized for accurately inserting foreign genes into the genome. HR occurs during the S/G2 phase, and the DNA mismatch repair (MMR) pathway is inextricably linked to HR to maintain HR fidelity. This study was conducted to investigate the effect of inhibiting MMR-related genes using CdCl2, an MMR-related gene inhibitor, on HR efficiency in HC11 cells. Methods: The mRNA and protein expression levels of MMR-related genes (Msh2, Msh3, Msh6, Mlh1, Pms2), the HR-related gene Rad51, and the NHEJ-related gene DNA Ligase IV were assessed in HC11 cells treated with 10 μM of CdCl2 for 48 hours. In addition, HC11 cells were transfected with a CRISPR/sgRNA expression vector and a knock-in vector targeting Exon3 of the mouse-beta casein locus, and treated with 10 μM cadmium for 48 hours. The knock-in efficiency was monitored through PCR. Results: The treatment of HC11 cells with a high-dose of CdCl2 decreased the mRNA expression of the HR-related gene Rad51 in HC11 cells. In addition, the inhibition of MMR-related genes through CdCl2 treatment did not lead to an increase in knock-in efficiency. Conclusions: The inhibition of MMR-related gene expression through high-dose CdCl2 treatment reduces the expression of the HR-related gene Rad51, which is active during recombination. Therefore, it was determined that CdCl2 is an inappropriate compound for improving HR efficiency.
        4,000원
        27.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study on webGl efficiency in Unity servers was conducted. There are various ways to upload a build file made with Unity to a web server. In fact, to classify it that way, it would not be an exaggeration to say that there are as many developers as there are. In this paper, it is mainly classified into four types and introduced. First, there are ways to package and distribute the Unity project itself, distribute it as a standalone or mobile build, distribute it as a webplayer build, and distribute it as a WebGL build. I would like to briefly introduce each method, look at the simplest of them, the distribution method in WebGL, and study the efficiency of this method in detail. Through this study, we can use Unity for the first time to help people who are thinking of deploying servers or are interested in basic engines and server upload methods. In this paper, we will first introduce the simplest way of building WebGL, then explain and compare the four distribution methods, and finally compare them with the efficiency of the WebGL method. This will support opinions on efficiency.
        4,000원
        28.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to develop a system to reduce ultrafine dust using hygroscopic materials such as glycerin and propylene glycol. Prior to the development of an ultrafine dust reduction system, the moisture condensation efficiency of glycerin and propylene glycol was investigated based on relative humidity (RH). The results showed that when no substances (glycerin and propylene glycol) were added to a tedlar bag, the relative humidity and temperature remained constant. The moisture condensation efficiency of glycerin was 60%, and the time it took to reach 50% of the initial relative humidity was about 40minutes. In the case of propylene glycol, the moisture condensation efficiency was 75%, and the time it took to reach 50% of the initial relative humidity was about 10 minutes. When glycerin and propylene glycol mixture was added, the moisture condensation efficiency was 68% and it took 20 minutes to reach 50% of the initial relative humidity. These results suggest that hygroscopic materials such as glycerin and propylene glycol can actually condense moisture in the atmosphere. In addition, considering actual atmospheric conditions, the relative humidity was set to 60% and 40% or less, and the moisture condensation efficiency was measured. The results showed that the mixture of glycerin and propylene glycol yielded the highest condensation efficiencies, at 69% and 62%, respectively. Therefore, it is preferable to use a mixture of glycerin and propylene glycol to condense moisture in the range of relative humidity in the actual atmosphere.
        4,000원
        29.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present numerical research, develop a high-efficiency fan model to improve the performance of the cooling fan, which accounts for a lot of weight in the efficiency of the cooling tower. For this purpose, analyze the shape of the existing cooling fan model and use CFD. The main variable set in the analysis of the cooling fan model is the pitch angle, and the range of the pitch angle was investigated in the range of 0° to 20°. The purpose of this research is to select the optimum driving condition by using CFD for setting the pitch angle that depends on the existing experience. The research results showed the best results when the pitch angle range was 15°~18°.
        4,000원
        30.
        2023.07 구독 인증기관·개인회원 무료
        Social media began to boom in the 2000s. According to statistics, there are 92.3% of internet users are social media users who spend nearly two and a half hours daily on social media. Instagram is considered the most popular image-sharing platform, with more than 1.2 billion monthly active users. Meanwhile, consumers nowadays refer to and follow online reviews to assist their decision-making process more efficiently.
        31.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focused on using indirect filtration through riverbeds to produce high-quality drinking water. Data on water quality from a water intake facility(capacity 10,000 m3/day) and nearby rivers were collected over a three-year period. The average intake facility specifications were found to be a specific surface area of 58 balls/m2, a mean particle size of 24 mm, an inflow velocity of 2.2 cm/sec, and a burial depth of 5 m. The water quality improvement rate was assessed as grade Ia, surpassing the adjacent river’s water quality. Correlation analysis showed a weak correlation between opening ratio, Suspended Solid (SS), and Biochemical Oxygen Demand (BOD) compared to total coliforms and fecal coliforms. The correlation coefficient R value of SS was -0.614, BOD was –0.588, total coliforms -0.870, and fecal coliforms -0.958. The R value shows a negative value, which showed that the larger the opening rate, the lower the removal rate of water pollutants. The correlation coefficient R values according to the depth of burial were found to be BOD 0.914, SS-0.124, total coliforms 1.000, and fecal coliforms 0.866. The deeper the burial depth, the higher the removal rate of BOD and microbial groups.
        4,000원
        32.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Daechung Reservoir has been suffering from severe cyanobacterial blooming periodically due to the water pollutants from the watershed, especially nutrients from nonpoint sources. As a countermeasure, an artificial wetland was constructed to mitigate the pollutant load from the watershed by utilizing the vegetation. We investigated the water quality of the influent and outflow of the wetland during years 2014~2020 to evaluate the performance of pollutant removal through the wetland. Major pollutants (e.g. BOD, COD, SS, T-N, and T-P) were largely reduced during the retention in the wetland while nutrients removal was more efficient than that of organic matters. Pollutant removal efficiency for different inflow concentrations was also investigated to estimate the wetland’s capability as a way of managing nonpoint sources. The efficiency of water treatment was significantly higher when inflow concentrations were above 75th percentile for all pollutant, implying the wetland can be applied to the pre-treatment of high pollution load including initial rainfall runoff. Furthermore, the yearly variation of removal efficiency for seven years was analyzed to better understand long-term trends in water treatment of the wetland. The annual treatment efficiency of T-P was very high in the early stages of vegetation growth with high concentration of inflow water. However, it was confirmed that the concentration of inflow water decreased, vegetation stabilized, and the treatment efficiency gradually decreased as the soil was saturated. The findings of the study suggest that artificial wetlands can be an effective method for controlling harmful algal blooms by alleviating pollutant load from the tributaries of Daechung Reservoir.
        4,500원
        33.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to analyze the efficiency of the safety and management of private highways. METHODS : Variables were selected based on the data and performance related to the safety of 18 private highways. The appropriateness of operations management was reviewed using Data Envelopment Analysis (DEA) analysis. Items with a scope for improvement were reviewed and adjustment measures were presented. RESULTS : To increase safety management efficiency, the degree of reduction in personnel and operating expenses was presented based on the relative efficiency group. CONCLUSIONS : It is necessary to adjust the appropriate management organization and operating costs according to the characteristics of each route. Moreover, the limitations of the study and possible improvements were presented.
        4,000원
        34.
        2023.05 구독 인증기관·개인회원 무료
        Metals such as stainless steel and alloy 600 are used as structures and materials in nuclear power plants due to their excellent mechanical properties and heat resistance. And recently thermal and mechanical cutting technologies are being actively researched and developed for dismantling NPP. Among them, the mechanical cutting method has the advantage of less secondary waste generation such as fume and fine dust, but according to the wider the cutting range, the reaction force and the cutting device size are increased. In this paper, plasma assisted milling has been proposed to reduce the reaction force and device size, and the plasma efficiency was measured for SUS 316L. The plasma torch was operated at the level of 3 to 4 kW so that it was heated only without cutting. And the feedrate was set at 150 to 250 mm/min. The test confirmed that the plasma efficiency was 35% about SUS 316L, and it is expected that the numerical analysis using these test results can be used as basic data for plasma assisted milling.
        35.
        2023.05 구독 인증기관·개인회원 무료
        The most important thing in development of a process-based TSPA (Total System Performance Assessment) tool for large-scale disposal systems (like APro) is to use efficient numerical analysis methods for the large-scale problems. When analyzing the borehole in which the most diverse physical phenomena occur in connection with each other, the finest mesh in the system is applied to increase the analysis accuracy. Since thousands of such boreholes would be placed in the future disposal system, the numerical analysis for the system becomes significantly slower, or even impossible due to the memory problem in cases. In this study, we propose a tractable approach, so called global-local iterative analysis method, to solve the large-scale process-based TSPA problem numerically. The global-local iterative analysis method goes through the following process: 1) By applying a coarse mesh to the borehole area the size of the problem of global domain (entire disposal system) is reduced and the numerical analysis is performed for the global domain. 2) Solutions in previous step are used as a boundary condition of the problem of local domain (a unit space containing one borehole and little part of rock), the fine mesh is applied to the borehole area, and the numerical analysis is performed for each local domain. 3) Solutions in previous step are used as boundary conditions of boreholes in the problem of global domain and the numerical analysis is performed for the global domain. 4) steps 2) and 3) are repeated. The solution derived by the global-local iterative analysis method is expected to be closer to the solution derived by the numerical analysis of the global problem applying the fine mesh to boreholes. In addition, since local problems become independent problems the parallel computing can be introduced to increase calculation efficiency. This study analyzes the numerical error of the globallocal iterative analysis method and evaluates the number of iterations in which the solution satisfies the convergence criteria. And increasing computational efficiency from the parallel computing using HPC system is also analyzed.
        36.
        2023.05 구독 인증기관·개인회원 무료
        In order to use nuclear energy stably, high level radioactive waste including spent nuclear fuel that is inevitably discharged from nuclear power plants after electricity generation must be managed safely and isolated from the human living area for a long period of time. In consideration of the accumulated amount of spent nuclear fuel anticipated according to the national policy for HLW management, the area required for the deep geological repository facility is expected to be very large. Therefore, it is essential to conduct various studies to optimize the area required for the disposal of spent nuclear fuel in cases where the nationally available land is extremely limited, such as in Korea. In this study, as part of such research, the strategies and the requirements for the preliminary design of a high efficiency repository concept of spent nuclear fuel were established. For PWR spent nuclear fuel, seven assemblies of spent nuclear fuel can be accommodated in a disposal canister, and high burnup of spent nuclear fuel was taken into consideration, and the source terms such as the amount and time of discharge and disposal were based on the 2nd national basic plan. By evaluating the characteristics, the amount of decay heat that can be accommodated in the disposal canister was optimized through the combination of seven assemblies of spent nuclear fuel. The cooling period of the radiation source for the safety assessment of the repository system was set at 55 years, and the operation of the repository would start from 2070 and then the disposal schedule would be conducted according to the disposal scenario based on the national basic plan. With these disposal strategies described above, the main requirements for setting up the conceptual design of the high efficiency repository system to be carried out in this study were described below. • A combination of seven spent nuclear fuels with high heat and spent nuclear fuels with low heat was loaded into a disposal canister, and the thermal limit per disposal canister was 1,600 W. • In order to maintain the long-term performance of the repository, the maximum temperature design limit in the buffer material was set to 130°C. • In the deep disposal environment, the safety factor [yield strength/maximum stress] required to maintain the structural stability of the disposal canister should be maintained at 2.0 or higher so that integrity of the canister can be maintained even under long-term hydrostatic pressure and buffer swelling pressure in the deep disposal environment. • The repository should have a maximum exposure dose of 10 mSv/yr or less, which is the legal limit in case of a single event such as an earthquake, and the risk level considering natural phenomena and human intrusion, which is less than the legal limit of 10-6/yr. These strategies and requirements can be used to develop the high-efficiency geological disposal concept for spent nuclear fuels as an alternative disposal concept.
        37.
        2023.05 구독 인증기관·개인회원 무료
        As Korea has relatively small land area and large population density compared to other countries considering the DGD concept such as Finland and Sweden, improvements of disposal efficiency in the viewpoint of the disposal area might be needed for the current disposal system to alleviate the difficulties of site selection for the HLW repository. In this research, we conduct a numerical investigation of the disposal efficiency enhancement for a high-level radioactive waste (HLW) repository through three design factors: decay heat optimization, increased thermal limit of buffer, and double-layer concept. In the optimized decay heat model, seven SNFs with the maximum and minimum decay heat depending on actual burn-up and cooling time are iteratively combined in a canister. Thermal limit of buffer is assumed as 100°C and 130°C for reference and high-efficiency repository concepts, respectively. By implementing an optimized decay heat model and a single-layer concept with a thermal limit of buffer set at 100°C, the disposal efficiency increases to 2.3 times of the improved Korean Reference disposal System (KRS+). Additionally, incorporating either an increased thermal limit of buffer to 130°C or a double-layer concept leads to a further 50% improvement in disposal efficiency. By integrating all three design factors, the disposal efficiency can be enhanced up to five times that of the KRS+ repository. Our analysis of rock mass stability reveals that increasing the thermal limit of buffer can generate rock spalling failure in a wider area. However, when accounting for the effect of confining stress by swelling of buffer and backfill using the Mohr-Coulomb failure criteria, the rock mass failure only occurred at the corner between the disposal tunnel and deposition hole when the thermal limit of buffer was increased and a single-layer concept was applied. The results given in this study can provide various options for designing the high-efficiency repository in accordance with the target disposal area and quality of the rock mass in the potential repository site.
        38.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the development of drone technology, drones are being used in various industries. In general, drones use lithium-based battery pack, which is sensitive to external impact and temperature characteristics. Therefore, in order to prevent this problem, a battery case for protecting the battery from the outside is used. Usually, carbon fiber is used as case material, carbon fiber is expensive and has disadvantages of being difficult to manufacture. In this study, a battery case was fabricated to minimize the influence of external impact and temperature by using expanded polypropylene material, and also the battery efficiency test was performed using fabricated case. After basic design for battery case was conducted, a system capable of maintaining temperature was constructed by attaching a surface heating element inside the case, and the effect of maintaining temperature according to the presence or absence of the case was confirmed. Using manufactured prototype case, flight tests were carried out to check the battery voltage level according to the presence or absence of the case and to analyze the effect of improving the battery efficiency for the flight time of the drone.
        4,000원
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