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        검색결과 1,294

        101.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electrochemical capacitive properties of biomass-derived activated carbons are closely dependent on their microscopic structures. Here, activated carbon fibers (ACFs) were prepared from natural cattail fibers by carbonization and further chemical activation. The activation temperature affected on the microscopic structures and electrochemical properties of the activated carbon fibers. The results show that the optimum activation temperature is 800 °C. And the as-prepared ACF- 800 possesses high micropore specific surface area of 710.4 m2 g− 1 and micropore volume of 0.313 cm3 g− 1, respectively. For supercapacitor applications, the ACF-800 displays a high specific capacitance of 249 F g− 1 at a current density of 0.05 A g− 1, excellent rate performance and cycle stability in a three-electrode system. The excellent electrochemical performance indicated that the obtained activated carbon fibers could be a promising electrode material in supercapacitor.
        4,000원
        102.
        2022.05 구독 인증기관·개인회원 무료
        Several previous simulation studies using various geochemical models have been carried out in several major analogue sites. The cases are beneficial when these studies provided the possibility of testing the geochemical models to be used to describe the migration of radionuclides in a future radioactive waste repository system. It was possible to interpret the complex transport behaviour of radionuclides such as uranium and thorium in an environment. We organize major natural analogue study sites from the previous literatures that provided information on the general geochemistry of the sites, in terms of groundwater composition and mineralogy. Also, we calculated aqueous speciation and the solid phases most likely to control their solubilities. The results obtained from the previous studies and this study vary depending on the tools used and on the conceptual models followed. Also, the results differed from the actual measured concentrations of trace metals or radionuclide analogues. The results obtained from these tests identify the main mathematical limitations of available geochemical models. However, the modelling results using a geochemical code with the thermodynamic database simulated well the observed behaviour of radionuclides, especially to identify the dominant processes controlling actinide mobilization and fixation. It was a useful outcome in terms of building confidence on the current geochemical tools to predict the concentrations of radionuclide analogues once the major geochemical characteristics were known. This study allows improving specific aspects of geochemical modelling using major natural analogue sites.
        103.
        2022.05 구독 인증기관·개인회원 무료
        The natural barrier, a component of the deep disposal system, has site-specific characteristics depending on the site of the repository, and is one of the main considerations for long-term safety evaluation after closure along with the engineered barrier among the multiple barrier systems of the repository. The natural barrier is defined in Korea as the natural underground and surface structures that can restrict the exposure of radioactive waste, human intrusion or groundwater infiltration into a disposal facility, and the transfer of radionuclides. It includes bedrocks and soils surrounding the engineered barriers of radioactive wastes [Notice of the NSSC, No. 2020021]. This study analyzed foreign regulatory requirements related to natural barriers, requirements for natural barrier and performance target of Sweden and Finland (safety functions and target characteristics of natural barriers, e.g. natural barrier composition, geological characteristics, hydrogeological characteristics). Overseas regulations and cases referenced to derive regulations of general safety requirements on natural barrier are IAEA SSG-14, SSMFS 2008:21 in Sweden, STUK/Y/4/2018 in Finland, and POSIVA SKB Report 01, a joint report between POSIVA and SKB. The repository site and repository depth should be chosen so that the geological formation provides adequately stable and favorable conditions to ensure that the repository barriers perform as intended over a sufficient period of time. The conditions intended primarily concern temperature- related, hydrological, mechanical (for example, rock mechanics and seismology) and chemical (geochemistry, including groundwater chemistry) factors. Furthermore, the repository site should be located at a secure distance from natural resources exploited today or which may be exploited in the future [SSMFS 2008:21]. Finland regulations also suggests similar requirements [STUK Y-4-2018]. According to the above regulations, POSIVA SKB report 01 mentions both the host rock and the underground opening as natural barriers and requires a safety function, and the main safety functions of the host rock and underground opening are as follows: (1) Isolation from the surface environment; (2) Favorable thermal conditions; (3) Mechanically stable conditions; (4) Chemically favorable conditions; and (5) Favorable hydrogeological conditions with limited transport of solutes. Such safety functions would provide insight for understanding of the natural barrier of deep geological disposal system.
        104.
        2022.05 구독 인증기관·개인회원 무료
        The mechanical, hydraulic, thermal, and chemical properties of the subsurface can have a significant effect on the long-term performance of an underground facility. Therefore, it is important to accurately estimate the aquifer properties in order to predict the groundwater flow and solute transport and thus ensure the stability and safety of a high-level radioactive waste disposal. Using heat as a tracer has become a popular tool for the subsurface characterization. Recent studies have demonstrated that heat tracing is an effective approach to quantify both hydrogeological and thermal subsurface properties. However, most studies in natural conditions assume the local thermal equilibrium (LTE) between the solid and fluid phases, ignoring heat exchange between them. The LTE assumption has not yet been verified by experiments. This work investigates the validity of the LTE assumption by performing the laboratory tracer tests using both solute and heat in a porous medium under natural groundwater flow velocities (Reynolds number, Re < 0.37). The experimental results showed that the LTE assumption can be violated even under natural groundwater flow conditions. The violation of LTE (LTNE) had a significant impact on mechanical dispersion, whereas its effect on velocity was negligible. These results provide the first experimental evidence for LTNE effects in natural conditions. Therefore, it is necessary to consider LTNE effects especially when the mechanical dispersion is evaluated using heat tracing.
        105.
        2022.05 구독 인증기관·개인회원 무료
        Multiple sorptive sites on natural illitic clays (e.g., frayed edge [FES], type II [TS], and planar sites [PS]) play an important role to diverse 137Cs immobilization in soil and aquifer environments. This study investigated the Cs sorption capabilities of 10 natural illitic clays at ranged Cs concentrations (1 ×10−7 to 1×10−3 mol·L−1) under various competing potassium concentration (distilled water to 1×10−1 mol·L−1). Additionally, multisite cation exchange model was performed to evaluate the best-fit sorption model and optimize the sorption capacities and affinities of multiple sorptive sites for Cs. Here, the experimental Cs sorption isotherms varied among 10 illtic clays, indicating different sorption capacities of Cs on illitic clays. The best-fit sorption model exhibited that variable Cs sorption of 10 illitic clays was significantly related to the sorption capacities at the FES (1.76 × 10−5 to 1.12×10−4 eq·kg−1), TS (1.59×10−3 to 9.76×10−3 eq·kg−1), and PS (2.14×10−2 to 1.51×10−1 eq·kg−1), respectively. The FES predominantly contributed to Cs sorption at low aqueous concentrations, whereas the TS and PS sorbed Cs at high concentrations. These sorption capabilities of multiple sorptive sites were correlated to illite contents and crystallinity of illitic clays, implicating that such parameters could be key factors to predict the Cs sorption for natural illitic clays in soil and aquifer environments. Finally, 1-D transport simulations represented that the severe Cs retardation occurred at low Cs concentration, implying that the FES predominantly affected to Cs transport in actual radioactive contamination sites (i.e., where low Cs concentration prevails), compared to the TS and/or PS.
        106.
        2022.05 구독 인증기관·개인회원 무료
        Uranium isotopes (238U, 235U, and 234U) found in natural environments and their activity ratios (235U/238U and 234U/238U) have been used as an important tool in investigating various geological processes, especially in natural analogue studies. Occurrence and fractionation of uranium isotopes in nature between 238U, 235U, and 234U were investigated. Various measurement methods have been used for the determination of isotopic ratios and geochronology. Thus, we reviewed and summarized the measurement methods such as alpha spectrometry, gamma spectrometry, thermal ionization mass spectrometry (TIMS), secondary ion mass spectrometry (SIMS) with sensitive high resolution ion microprobe (SHRIMP), and multiple-collector inductively coupled plasma mass spectrometry (MCICPMS). Research status of natural analogue studies carried out using uranium isotopes and their isotopic ratios were also reviewed and summarized in terms of long-term behaviors of radionuclides in various foreign uranium deposits as analogues of high-level radioactive waste repositories. Research results for mineralogical, geochemical, and biogeochemical behaviors of uranium in various natural analogue sites were collected and analyzed to investigate the migration and retardation processes of uranium through geological media. These long-term behaviors of uranium and uranium isotopes include dissolution/precipitation of uranium minerals, interactions of uranium with various fracture minerals including sorption and incorporation, redox reactions by minerals and microbes, and hydrological groundwater flow thorough rock fracture systems including identification of flow paths and groundwater circulation. The results of this study will contribute to performing future natural analogue studies in domestic uranium deposits and provide basic information and knowledge for understanding long-term geochemical and geochronological behaviors of radionuclides in a high-level radioactive repository.
        107.
        2022.05 구독 인증기관·개인회원 무료
        The radioactive waste repository consists of an engineered barrier and a natural barrier and must be managed safely after isolation. We classify the geological events of natural barriers for the evaluation of their present and future disposal stability assessment, they can be divided into regional and regional evolutions according to their scale. Regional evolution can be quantitatively explained by plate tectonics and regional rock distribution, and local evolution can be explained by petrological, mineralogical evidence and ductile, brittle deformation. Plate tectonics can explain the change quantitatively by restoring the direction of the Earth’s magnetic field recorded when rocks were formed. The time units for these changes are tens of millions of years to hundreds of millions of years, but plate tectonic is a way to estimate geological history. It can be assessed by extrapolating past knowledge considering the known geological events of radioactive waste repository. It is possible to derive a conservative value of the change of the geological environment in the time unit of disposal stability. The Korean Peninsula belongs to the edge of the Eurasian plate and is divided into Gyeonggi, Yeongnam Massif, Okcheon orogeny belt, and Gyeongsang Basin. To quantitatively determine their geological history, we collected paleomagnetic data using rocks from the Korea Peninsula (paleomagnetic database and papers). We attempted to carry out the apparent polar wander paths (APWPs) on the Korean Peninsula by collecting and sorting data. Since the Korean Peninsula is composed of multiple massifs, this APWP is expected to serve as a basis for explaining the local crustal rotation or brittle ductile deformation. Furthermore, by extrapolating the change pattern from the past to the present, it can contribute to the estimation of the future geological evolution.
        108.
        2022.05 구독 인증기관·개인회원 무료
        A methodology is under development to restore and predict the long-term evolution of the natural barrier comprise the site of radioactive waste disposal for surface geological outcrop, tunnel face and drill core. Considering the condition that the radioactive waste repository should be located in the deep part, the drill core is an important subject that can identify deep geological properties that could not be confirmed near the surface. In this study, we investigated proper age dating methods to construct lithological model of the disposal site with regard to the long-term safety. Also, preliminary age dating locations were selected using the lithological distribution results by depth through geochemical and micro-structural analysis for the deep drill cores excavated around KURT. In the study area, the dikes presumed the Cretaceous were intruded by Jurassic granites. As for the granotoids, U-Pb age dating for zircon, which is resistant to deformation or metamorphism and has loss, is often used. In the case of the dikes, K-Ar and 40Ar/39Ar age dating for the argon captured in the rocks after magmatism is often used. Through U-Pb zircon ages of KURT site granotoids, we expect to solve the clustering problem (granite and granodiorite), which is different from precious chemical analysis (XRF) results and TAS-diagrams. 40Ar/39Ar age dating to be used for the dikes is suitable for the perspective of lithological model of the disposal site. Because, it can compensate for accuracy problems such as sample heterogeneity in K-Ar age dating and is used for volcanic rocks. In the further study, we plan to determine the appropriate sampling locations by the selected age dating methods from the perspective of disposal in this study.
        109.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bulbophyllum auricomum Lindl. is a rare orchid and has flowers with an attractive fragrance. The present study investigated the tissue culture method for micropropagation. Capsules derived from artificial self-pollination were obtained for the best seed germination in MS basal medium. Plant growth regulators (1.0 mg·L-1 of BAP and 2.0 mg·L-1 of NAA) were affected by callus induction from subcultured pseudobulb explants. For the callus subculture, different natural plant extracts were tested in 11 treatment media. Among them, MS medium with 150 mL·L-1 of coconut water was generally effective in fresh weight (1.75 ± 0.08) and (3.01 ± 0.20) of callus proliferation and PLBs induction at 1 and 2 months, respectively, followed by an MS combination of 30 g·L-1 of banana and 20 g·L-1 of potato extract. The results of a comparative study of different MS mediums containing plant growth regulators with a natural extract combination and MS medium supplemented with natural extract only showed that MS medium supplemented with a combination of natural extracts (150 mL·L-1 of coconut water) and plant growth regulators (2.0 mg·L-1 of BAP and 1.0 mg·L-1 of NAA) obtained the highest shoot regeneration (3.37 ± 0.17) and (6.41 ± 0.68) after 1 month and 2 months of culturing, respectively.
        4,000원
        110.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the effect of side vent heights on temperature and relative humidity inside and outside the single-span plastic greenhouse (W: 7 m, L: 40 m H: 3.9 m) during natural ventilation. Four different heights (120, 100, 80, 60 cm) of the side vent were used as an experimental condition. Variations of temperature and relative humidity inside and outside the greenhouse and the differences between heights were compared by using one-way ANOVA. In the daytime, the difference in temperature between inside and outside the greenhouse was dropped from 14.0°C to 7.1°C as the side vent height increased. The temperature difference in the nighttime was less than 0.2°C regardless of the height. One-way ANOVA on the temperature difference between heights presented that the statistical significance was founded between all of the combinations of height in the daytime. The difference in relative humidity between inside and outside the greenhouse was grown from –13.8% to – 22.2% with a decrease in the side vent height. The humidity difference in the nighttime was less than 1% regardless of the height. One-way ANOVA on the humidity difference revealed that most of the side vent heights showed significance in the daytime but between 100 and 80 cm was not significant. It seemed because the external air became cooler during the experiment with a height of 80 cm. Conclusively, this study empirically demonstrated that the higher side vents resulted in the decrease of differences in temperature and relative humidity between inside and outside the greenhouse, and also the effect of side vent height was statistically significant. This study may be helpful for deciding the height of the side vent effective for controlling temperature and relative humidity in a single-span greenhouse during natural ventilation.
        4,000원
        111.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 최근 20년간(2001~2020) 소나무에 관한 주요 연구 주제 및 연구영역 분석을 통한 향후 연구 방향성을 파악하고자 하였다. 이를 위해 Python.3.9.0과 Textom를 활용하여 RISS와 Web of Science의 소나무 관련 총 3866편의 논문 제목과 키워드 데이터를 수집하고 분석을 실시하였다. 분석 결과, 국가별 총 논문 수는 일본 383편(46.8%), 한국 363편(44.4%), 중국 78편(9.5%)순으로 소나무 자생국가를 중심으로 한 관련 연구들이 활발히 진행되었다. 단어 빈도 및 TF-IDF, N-gram, CONCOR 분석을 통해 국내와 국외에서 소나무 관련 주요 연구 주제는 소나무재 선충으로 나타났으며, 사회 및 경제적 환경, 관련 정책 등 차이에 의해 국내와는 달리 국외에서는 '균근' 관련 연구가 주요 연구 영역으로 도출되었다. 또한 소나무 관련 연구는 일부 인문 사회학적인 연구들이 진행되었지만 주로 생태적인 측면에 집중되어 있는 것으로 나타 났다. 이에 소나무의 인문·사회학적 가치를 고려할 때 향후 연구에서는 이와 관련 후속연구가 필요할 것으로 판단된다.
        4,500원
        116.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 제초제 살포 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)에 따른 귤 응애의 개체군 동태를 구명하고자 수행되었다. 두 가지 기본적인 가설로 1) 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응 애의 발생을 감소시키는 요인으로 작용하며, 2) 합성피레스로이드계는 천적을 제거하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 관측 된 천적 개체군(주로 이리응애류와 마름응애류)의 발생은 가정에 근거한 기대치와 크게 다르지 않았다. 2011년의 경우 NW+NP 처리구와 W+NP 처리구에서 차이가 있었으나, 2012년 실험에서는 기대치와 관측치가 거의 일치하였다. 전체적으로 약제효과가 뚜렷하게 나타나서 합성 피레스로이드계 살포시 천적이 유의하게 감소하였다. 잡초효과는 엇갈리는 결과를 보였는데, 봄-유래 여름 개체군 대비 가을 개체군의 증가 등을 고려할 때 초생재배를 하는 경우 천적의 발생이 증가하였다. 다만, 합성피레스로이드계 살포구에서 귤응애가 감소하는 비이상적인 결과는 귤응 애의 합성피레스로이드계에 대한 강한 기피성을 전제로 해석할 수 있었다.
        4,300원
        117.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해안가 복합재해는 기후변화 등의 영향으로 인해 그 규모 및 피해정도가 증가하고 있어, 이에 대한 적절하고 체계적 관리 가 필요하다. 하지만 해안가 복합재해에 대해 우리나라는 법제도적인 미비가 있고, 따라서 해안가 복합재해 관리구역 제도를 위한 법 률적 마련할 필요가 있다. 이를 위해 본 연구에서는 해당 제도가 「자연재해대책법」의 규정을 중심으로 운영되는 것을 전제로 하여 크게 과학기반 관리, 협력적 관리, 그리고 적응관리라는 세 가지 측면에서 선행된 이론적 연구를 토대로 적절한 규범화 작업의 방향을 검토하였다. 그 결과 효과적인 과학기반 관리를 위해서는 위험성 평가 도입이 필요하고, 이를 통해 얻어진 결과를 기준으로 구역범위 설정 및 그에 따른 차등적 대책을 설정하도록 해야 할 것이다. 협력적관리 측면에서는 다양한 부처들이 해안가 복합재해와 관련되어 있기에 다양한 주체의 협력 기반을 제도화할 필요가 있는데, 그 방안으로 행정안전부, 국토교통부, 해양수산부, 환경부, 지자체 등이 함 께 정책ㆍ제도를 협의할 수 있는 정책협의회를 구성할 것을 제안한다. 마지막으로 적응관리 측면에서 구조적 대책의 한계를 비구조적 대책을 병행 추진하여 보완할 필요성이 있음이 나타났으며, 따라서 법을 개정함에 있어 재해관리를 위한 계획 수립 시 비구조적 대책 을 활용을 촉진할 수 있는 지원 방안을 담아야 할 것이다.
        4,000원
        118.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was designed to verify what effect the use of a natural ventilation system can have on improving indoor air quality with regard to radon in various concentration ranges in an apartment house. The results show that both high (2~3 times higher than 148 m3) and low (similar to 148 Bq/m3) levels of indoor radon concentrations can be reduced close to and/or below the Korean IAQ guideline within 6 hours when the natural ventilation system is operated at approximately an air change rate of 0.5. In the case of an air change rate of 0.3, however, the indoor radon levels cannot meet the national guidelines and the reduction effect was insufficient with regard to various radon concentrations. Typically, the air change rate of a natural ventilation system is affected by meteorological factors such as temperature, relative humidity, wind speed, pressure. Its effectiveness varies according to such factors, for that reason, the reduction effects on radon did not increase proportionally with the ventilation time in this study.
        4,000원
        119.
        2021.12 구독 인증기관 무료, 개인회원 유료
        This study conducted a survey and evaluation on ‘The 2021 Jeju World Natural Heritage Festival’ with a framework of various stakeholders related to festivals. While aiming for the essential context of the celebration, we tried to find suggestions to ensure the continuity of the celebration and the designation of the World Natural Heritage. As a methodology, surveys and interview surveys were conducted in parallel with the framework of multifaceted evaluation. To summarize the important contents presented as policy suggestions, first, it is necessary to expand the concept of ' encounter with hidden nature' from the positivity of the concept of 'encounter with hidden nature' to have fellowship with mankind about natural heritage. For reference to this, efforts should be made to secure the continuity of the designation of World Natural Heritage through a contextual approach using the frame of 'encounter'. Second, since the participation of experts can help in many ways, it is necessary to encourage many experts to participate as a staff or activist. Third, it is necessary to sublimate Jeju's natural heritage into a public celebration without damaging it. Finally, it should be a festival centered on local communities and local residents. It is necessary to actively seek a system in which the World Natural Heritage Village Preservation Association, which will be created (tentative name), will be centered and promoted by the villagers.
        4,200원
        120.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        아시아계통의 매미나방(Lymantria dispar asiatica) (나비목: 태극나방과)은 국내 토착해충으로서 지역에 따라 돌발적으로 대발생한 사례 가 있으며, 다양한 수목 및 농작물에 피해를 끼치는 광식성 해충이다. 특히 2019년 이후로 경기도, 충청도, 경북 북부지역에서 대발생하여 산림 및 인근지역 도심에 발생하여 산림 및 도시민들의 정서적 피해를 끼치기도 했다. 본 연구에서는 2020-2021년 경북 예천지역에서 알집을 채집하여 사육한 결과, 매미나방 핵다각체병바이러스(LdMNPV) 감염에 의해 79.65% (321/403마리)는 사육중 사망하였다. 염기서열 분석은 2021년 국내 12 지역에서 매미나방 유충을 36마리를 조사한 결과, LdMNPV의 late expression factor-8 (lef-8), polyhedrin (polh) 유전자의 종내변이율이 0.80%, 0.86%로 확인됐다. NCBI database 자료와 비교 분석한 결과 일본의 LdMNPV와 가장 유사했으며, 터키의 LdMNPV와 가장 큰 차이를 나타냈다. 본 조사를 통하여 LdMNPV는 높은 감염율을 나타냈고 매미나방 중요한 개체군 조절인자중 한가지로 작용할 것으로 판단된다.
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