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        검색결과 56

        1.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In ecosystems within limited resources, interspecific competition is inevitable, often leading to the competitive exclusion of inferior species. This study aims to provide foundational information for the conservation and restoration management of Microphysogobio rapidus by evaluating species’ ecological response to biological factors within its habitat. To understand this relationship, we collected food web organisms from site where M. rapidus coexist with Microphysogobio yaluensis, a specie ecologically similar to M. rapidus, and evaluated the trophic levels (TL), isotopic niche space (INS), and the overlap of INS among fishes within the habitat using stable isotope analysis. Our analysis revealed that the M. rapidus exhibited a higher TL than M. yaluensis, with TL of 2.6 and 2.4, respectively. M. yaluensis exhibited a broad INS, significantly influencing the feeding characteristics of most fish. Conversely, M. rapidus showed a narrow INS and asymmetric feeding relationships with other species, in habitats with high competition levels. This feeding characteristics of M. rapidus indicate that the increase in competitors sharing the similar resources lead to a decrease in available resources and, consequently, is expected to result in a decrease in their density.
        4,300원
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 기금조성용 옥외광고 산업의 현재를 분석하고, 산업 의 발전을 저해하는 요인으로 평가받는 불법 도로변 야립광고에 대한 해 법을 제시하고자 하는 것이다. 이를 위하여 전문가를 대상으로 하는 심 층 인터뷰를 실시하여 그 내용을 분석하였다. 이를 통해 본 연구는 기금 조성용 옥외광고가 옥외광고 산업의 발전에 중요할 역할을 했음을 확인 하였으나, 시스템과 비즈니스 차원에서 해결해야 할 여러 문제점이 있음 을 발견하였다. 또 불법 도로변 야립광고의 난립을 방지하기 위해 법적, 기술적, 경제적, 사회적 해법에 대한 전문가들의 다양한 의견을 수집함으 로써 관련 산업 정책에 대한 의미있는 기초자료를 제공한다는데 의의가 있다.
        6,300원
        3.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Small ponds, which exhibit unstable succession pattern of plankton community, are less well studied than large lakes. Recently, the importance of small ponds for local biodiversity conservation has highlighted the necessity of understanding the dynamics of biological community. In the present study, we collected zooplankton from three small reservoirs with monthly basis and analyzed their seasonal dynamics. To understand the complicated zooplankton community dynamics of small reservoirs, we categorized zooplankton species into four groups (LALF Group, Low Abundance Low Frequency; LAHF Group, Low Abundance High Frequency; HALF Group, High Abundance Low Frequency; HAHF Group, High Abundance High Frequency) based on their occurrence pattern (abundance and frequency). We compared the seasonal pattern of each group, and estimated community diversity based on temporal beta diversity contribution of each group. The result revealed that there is a relationship between groups with the same abundance but different occurrence frequencies, and copepod nauplii are common important component for both abundance and frequency. On the other hand, species included with LALF Group throughout the study period are key in terms of monthly succession and diversity. LALF Group includes Anuraeopsis fissa, Hexarthra mira and Lecane luna. However, groups containing species that only occur at certain times of the year and dominate the waterbody, HALF Group, hindered to temporal diversity. The results of this study suggest that the species-specific occurrence pattern is one key trait of species determining its contribution to total annual biodiversity of given community.
        4,800원
        4.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, Korean government has introduced Multi Metric Indices (MMI) using various biocommunity information for aquatic ecosystem monitoring and ecosystem health assessment at the national level. MMI is a key tool in national ecosystem health assessment programs. The MMI consists of indices that respond to different target environmental factors, including environmental disturbance (e.g. nutrients, hydrological and hydraulic situation of site etc.). We used zooplankton community information collected from Korean lakes to estimate the availability of candidate zooplankton MMI indices that can be used to assess lake ecosystem health. First, we modified the candidate indices proposed by the U.S. EPA to suit Korean conditions. The modified indices were subjected to individual index suitability analysis, correlation analysis with environmental variables, and redundancy analysis among indices, and 19 indices were finally selected. Taxonomic diversity was suggested to be an important indicator for all three taxonomic groups (cladoceran, copepod, rotifer), on the other hand, the indices using biomass for large cladocerans and copepods, while the indices using abundance were suggested for small cladocerans and rotifers.
        4,500원
        5.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Through sample-size-based rarefaction analyses, we tried to suggest the appropriate degree of sample concentration and sub-sample extraction, as a way to estimate more accurate zooplankton species diversity when assessing biodiversity. When we collected zooplankton from three reservoirs with different environmental characteristics, the estimated species richness (S) and Shannon’s Hʹ values showed different changing patterns according to the amount of sub-sample extracted from the whole sample by reservoir. However, consequently, their zooplankton diversity indices were estimated the highest values when analyzed by extracting the largest amount of sub-sample. As a result of rarefaction analysis about sample coverage, in the case of deep eutrophic reservoir (Juam) with high zooplankton species and individual numbers, it was analyzed that 99.8% of the whole samples were represented by only 1 mL of sub-sample based on 100 mL of concentrated samples. On the other hand, in Soyang reservoir, which showed very small species and individual numbers, a relatively low representation at 97% when 10 mL of sub-sample was extracted from the same amount of concentrated sample. As such, the representation of sub-sample for the whole zooplankton sample varies depending on the individual density in the sample collected from the field. If the degree of concentration of samples and the amount of subsample extraction are adjusted according to the collected individual density, it is believed that errors that occur when comparing the number of species and diversity indices among different water bodies can be minimized.
        4,200원
        6.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, there has been an increase in the morbidity of gastritis in Korea due to lifestyle factors mostly changes in eating habits and stress. Gastritis is more likely to progress to gastric cancer, and therefore it is important to prevent and manage gastritis through lifestyle adjustment and treatment at an early stage. In this study, cabbage, which was found to be effective in gastritis, was mixed and fermented with other crucifer plants such as kale and broccoli to evaluate the overall efficacy of fermented brassica puree on alcoholic acute gastritis. Based on our results, fermented brassica puree alleviated gastric injury induced by 150 mM HCl/60% ethanol. In addition, it was confirmed that PGE2, a gastric mucosal protective factor, was increased, and other positive effects such as an increase of MUC1 and regulation of PKC were observed. The results of this study suggest that fermented brassica puree can relieve acute alcoholic gastritis by regulating PGE and the expression of MUC1, a gene related to mucus secretion, and activating PKC, which is related to mucosal cell activity.
        4,000원
        8.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        LMU(Leg Mating Unit)는 해양구조물의 플로트오버 실치에서 활용되는 장비 중 하나로 충격을 흡수하는 부분과 결합부로 구성된다. 본 연구에서는 최적설계를 통해 부유식 해양구조물의 플로트오버 설치용 LMU의 성능을 개선하여 설계 요구 조건을 만족하는 설계를 개발하였다. 초기설계는 고정식 해양구조물의 플로트오버 설치용으로 개발된 것의 제원을 참조하였으며, 초탄성재료의 거동을 표현하기 위해 Mooney-Rivlin 모델을 활용하였다. 설계민감도해석 결과를 바탕으로 중요도에 따라 설계 변수들을 선별하였고, 진화 알고리듬 기반 최적설계를 수행하였다. 최적설계 문제에서 목적함수는 LMU의 중량이며, 제약 조건은 LMU에 작용하는 최대 폰-미세스 응력과 LMU의 성능을 평가할 수 있는 반발력이다.
        4,000원
        9.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Probiotics improve the immune system. However, the effects of its lactic acid bacteria on atopic dermatitis relief and inflammation improvement is not fully understood. Recently, one of the probiotics, Lactobacillus helveticus HY7801 (HY7801), was found to have an anti-inflammatory effect. In this study, we investigated the effects of HY7801 on atopic dermatitis-induced animal models. After four weeks of oral administration, the group treated with HY7801 showed amelioration of the atopic dermatitis compared to the group receiving placebo. In the HY7801 treated group, the epidermal hyper-proliferation and collagen deposition were inhibited compared to the placebo group, and the secretion amount of the inflammatory factors, such as TNF-α, IL-4 were reduced. In conclusion, these results suggest that HY7801 acts as a functional probiotic via amelioration of the atopic dermatitis such as a decrease of epidermal hyper-proliferation, and collagen deposition and anti-inflammatory effects.
        4,000원
        10.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this numerical study is to investigate the effect of shaft part’s diameter on the load distribution, under-fill, and metal-flow line characteristics in tubular & solid shaft yoke of Al-IMS. The outer diameter of tubular shaft yoke was changed from 30mm to 35mm, and the shaft diameter of solid shaft yoke was varied from 20mm to 25mm. In this results, the required load for production was linearly increased with increasing the tubular shaft yoke outer diameter. In the solid shaft yoke, the loads for the shaft part extending process were almost constant by 10,000kg, however, the loads for generating the yoke process, which were needed a lot of strain, were increased by 4,000kg with increasing the diameter of shaft part. The under-fill regions according to diameter of the shaft part were not observed in both products, and the metal-flow lines were also straight without folding phenomena.
        4,000원
        11.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this numerical study is to investigate the effect of aluminium material on the weight reduction in tubular shaft yoke and solid shaft yoke. The tubular shaft and the solid shaft were designed by 6 stage processes and the results were analyzed by using a finite element analysis method. The coefficient of friction was set to Oil_cold as referred to the analysis library. It was found that the weight was reduced as 65% with applying the aluminium alloy due to lower density than carbon steel. Von-mises stress values of applying aluminium alloy to the tubular shaft yoke and solid shaft yoke were lower than those of carbon steel because of the low yield stress of aluminium alloy. The folding and underfill phenomenon were not observed on the aluminium alloy in tubular shaft yoke and solid shaft yoke. From these results, the weight reduction of products and the extend life of dies can be expected when aluminium alloy is applied.
        4,000원
        12.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of blanching time (1-5 min), types of blanching solution (1% NaCl vs 1-3% sucrose), addition of packaging with blanching solution, and thawing methods (thawing in packaged versus depackaged units) on the qualities of frozen Aster scaber. As quality parameters, drip loss, moisture content, shear force, color, and sensory test were conducted. Aster scaber was blanched in 1% sucrose for 4 min and packaged with the same solution prior to freezing whereas frozen Aster scaber exhibited palatable quality when it was removed from the package and thawed in running water. Consequently, this study demonstrated that the optimized processing condition provided qualities like non-frozen control.
        4,000원
        13.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the changes in the physicochemical properties of soybean sprout, radish, and pork loin during frozen Bibimbab production. The qualities of soybean sprout were affected by the blanching, thawing, and cooking processes, with the blanching process particularly regarded as an important process to attribute the overall quality of the soybean sprouts in the final product. High weight loss of radish was found in the thawing and cooking processes, while the weight loss was relatively lower than that of soybean sprout. However, mixing with hot rice can be attributed for the steep decrease in shear force of the radish. For pork meat, normally thermal treatment such as mixing with hot rice and cooking manifested quality deterioration. Based on the results, mixing process appeared to be the most important process which affected the final quality of the materials. To improve the quality of final frozen Bibimbab, therefore, it was recommended to freeze the food ingredient separately from rice prior to packaging, which warranted the follow up exploration.
        4,000원
        14.
        2017.10 구독 인증기관·개인회원 무료
        온도 상승을 비롯한 기후의 변화가 빠르게 진행되고 있다. 이러한 기후의 변화는 우리나라 주요 작물인 벼(Oryza sativa)를 가해하는 해충의 발생 양상을 변화시키고 있다. 벼를 가해하는 해충 중, 중국 남부 및 동남아시아지역에서 비래하는 해충의 발생 실태 조사를 위해서, 경기도 및 충청남도의 4개 시군에 총 24곳의 포장을 선정하여중부지역 벼 재배지대별 비래해충의 발생 실태를 조사하였다. 한반도에 비래해충이 유입되기 전인 4월부터 벼수확 직전인 8월 말까지 주요 비래해충인, 애멸구, 벼멸구, 흰등멸구, 멸강나방, 혹명나방의 발생 실태를 조사하였다.나방류는 성페르몬 트랩을 이용하여 조사하였고, 멸구류는 동력흡충기, 육안조사, 쓸어잡기 및 끈끈이트랩을 이용하였다. 본 실태조사는 2016년에 시작하여 지속적으로 실시하고 있으며, 지속적인 실태조사를 바탕으로 향후 기후변화에따른 벼 재배지역에 발생하는 주요해충에 대한 발생 및 이동 예측모델 개발 및 방제대책 연구에 대한 기초자료로활용될 것이다.
        15.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fludarabine, a chain terminating anti-cancer drug, is a purine analogue that causes DNA strand breaks in normal cells. In this study, we determined if A. melanocarpa and Korean red ginseng extract mixture reduce cytotoxicity of fludarabine. Treatment of HaCaT cells with 10 μM of fludarabine for 24 hours decreased cell viability and increased DNA strand breaks. Treatment of A. melanocarpa and Korean red ginseng extract mixture for 24 hours increased cell viability as compared with single extract treatment. The protective effect of these extracts on cell activity increased in a concentration-dependent manner. DNA strand breaks induced by fludarabine decreased as concentration of extract mixture increased. p-H2AX level, a marker of DNA strand breakage, decreased depending on the concentration of extract mixture. The effect of mixed extract of A. melanocarpa and Korean red ginseng on DNA damage is due to the anti-oxidative effect of A. melanocarpa and signal transmission through glucocorticoid receptor upon binding of saponin of Korean red ginseng.
        4,000원
        16.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to solve the problem that was occurred during the spline processing in A-IMS tubular shaft. The upper dies were modelled conventional case and modified case. The tubular shafts were modelled as standard case and error case. The error case assumed production error of raw material. The material of tubular shaft was set to SCM 420H as refer to the analysis library. The simulation results were analyzed and compared in terms of metal flow, effective stress, and effective strain characteristics. The crushed and buckling problems were observed at the upper side of tubular shaft body when conventional upper die was applied. However, the crushed and buckling problems were solved when modified upper die was applied.
        4,000원
        17.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The object of this study is to improve the straightness in tubular shaft production. Die bearings of 1, 2 and 3 were inserted onto the lower die, respectively. In this study, the tubular shafts at the stage 5 were modelled as the standard and error cases. The error case assumes the production error of raw material. The coefficient of friction was set to the Oil_Cold conditions as referring to the analysis library. In the results, the effective stress was observed homogeneously on the distribution at yoke top in standard case. However, the effective stress was observed on the distribution at long section of yoke in case of the raw material with error. The metal flow line was stretched straight in standard case. On the other hand, the metal flow line was bent in all of error cases. The biggest displacement occurred when only one die bearing was applied. The smallest displacement occurred when two die bearings were applied in lower die.
        4,000원
        18.
        2016.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In regions of low-to-moderate seismicity, various types of lap splices are used for longitudinal reinforcement of columns at the plastic hinge zones. The seismic performance of such lap spliced columns, such as strength, deformation capacity, and energy dissipation, is affected by material strengths, longitudinal re-bar size, confinement of hoops, lap splice location, and lap splice length. In the present study, cyclic loading tests were performed for columns using three types of lap splices (bottom offset bar splice, top offset bar splice, and splice without offset bend). Lap splice length(40db and 50db) was also considered as test parameters. Ties with 90-degree end hooks were provided in the lap splice length. The test results showed that strength, deformation capacity, and energy dissipation of columns significantly differed depending on the details and the length of lap splices. The bottom offset bar splice showed high ductility and energy dissipation but low strength; on the other hand, the top offset bar splice and the splice without offset bend showed high strength but moderate ductility and energy dissipation.
        4,000원
        19.
        2016.10 구독 인증기관·개인회원 무료
        본 연구에서는 국내산 냉동 무의 품질 향상 및 보존을 위한 냉동 및 전처리 조건을 수립하고자 하였다. 국내산 무 를 3 cm 정방형으로 세절한 뒤 자연대류 냉동, 과냉각 후 냉동, 알긴산 침지 냉동, 알긴산 코팅 냉동을 실시하였다. 과냉각 후 냉동 처리는 무를 항온 저온 수조에서 느리게 냉각시켜 빙핵 형성이 야기된 이후 냉동고로 옮겨 후냉동을 실시하였다. 알긴산 침지 냉동은 1% sodium alginate 수용액에 무를 침지 시킨 후 즉시 냉동처리를 실시하였고, 알긴산 코팅 냉동은 1% sodium alginate 수용액에 무를 약 1분간 표면에 코팅 한 후 냉동하였다. 모든 냉동 처리구는 -18°C 자연 대류식 냉동고에서 실시하였다. 해동은 유수해동 (20°C)으로 진행하였다. 알긴산 침지냉동과 알긴산 코팅 냉동 처리구는 해동감량, 전단력 측면에서 모두 자연대류 냉동 처리구보다 우수한 결과를 나타내었다. 전단력의 경우, 자연 대류 냉동 처리구는 대조구보다 증가된 결과를 보였으나 알긴산 침지 및 코팅 처리구는 대조구와 유사한 결과를 나타 내었다. 또한 해동감량 역시 자연대류냉동 처리구가 알긴산 침지 및 코팅냉동 처리구보다 높은 값을 나타내었는데, 이 는 냉동 및 해동 과정에서 조직이 파괴되어 야기된 것으로 판단되었다. 알긴산 처리구 간의 특성을 비교하였을 때, 침 지 냉동 처리구가 코팅 냉동 처리구보다 더 우수한 결과를 나타내었다. 이 결과를 토대로 sodium alginate를 통한 전처 리가 냉동 무의 품질유지에 영향을 끼친 다는 것을 알 수 있었고, 최적 조건으로는 1% Sodium alginate 수용액 침지냉 동으로 평가되었다. 따라서 sodium alginate 처리는 냉동농산물의 전처리 방법으로서 품질유지 및 향상에 기여할 것으 로 예상되었다.
        20.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate earthquake responses of structures with basements affected by soil deposits, centrifuge tests were performed using an in-flight earthquake simulator. The test specimen was composed of a single-degree-of-freedom structure model, a basement and sub-soil deposits in a centrifuge container. The test parameters were the dynamic period of the structure model, boundary conditions of the basement, existence of soil deposits, centrifugal acceleration level, and type and level of input earthquake accelerations. When soil deposits did not exist, the earthquake responses of the structures with fixed basement were significantly greater than those of the structure without basement. Also, the earthquake responses of the structures with the fixed basement surrounded by soil deposits were amplified, but the amplifications were smaller than those of the structures without basement. The earthquake responses of the structures with the half-embedded basement in the soil deposits were greater than those estimated by the fixed base model using the measured free-field ground motion. The test showed that the basement and the soil deposit should be simultaneously considered in the numerical analysis model, and the stiffness of the half-embedded was not effective.
        4,300원
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