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        검색결과 35

        1.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Volcanic seawater has been naturally filtered and purified by volcanic rock layers. It contains abundant minerals such as calcium, magnesium, and iron. This study investigated the genotoxicity of calcium from Jeju lava seawater (CJLS). We performed bacterial reverse mutation assay, chromosomal aberration assay, and mammalian micronucleus test at up to 5,000 g/plate concentrations with or without metabolic activation to determine the CJLS genetic toxicity. None of these tests showed any mutagenic potential. The bacterial reverse mutation assay showed that the CJLS did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA with or without metabolic activation of the S9 mixture. The oral administration of CJLS also did not significantly increase the number of micronucleated polychromatic erythrocytes or the mean ratio of polychromatic to total erythrocytes. Additionally, CJLS did not cause a significant chromosomal aberration in CHL cells in the presence or absence of S9 activation. Therefore, CJLS could be considered as a reliable and safe functional food ingredient.
        4,000원
        2.
        2023.11 구독 인증기관·개인회원 무료
        Alpha activities can be used for categorization, transportation, and disposal of radioactive waste generated from the operation of nuclear facilities including nuclear power plants. In order to transport and dispose of such low- and intermediate-level radioactive waste (LILW) to the Wolsong LILW Disposal Center (WLDC) at Gyeongju, the gross alpha concentration of an individual drum should be determined according to the acceptance criteria. In addition, when the gross alpha concentration exceeds 10 Bq/g, the inventory of the comprising alpha emitters in the waste is to be identified. Gross alpha measurements using a proportional counter are usually straightforward, inexpensive, and high-throughput, so they are broadly used to assay the total alpha activity for environmental, health physics, and emergency-response assessments. However, several factors are thoughtfully considered to obtain a reliable approximate for the entire alpha emitters in a sample, which include the alpha particle energy of a particular radionuclide, the radionuclide that is used as a calibration standard, the uniformity of film in a planchet, time between sample collection and sample preparation, and time between sample preparation and counting. Korea Atomic Energy Research Institute (KAERI) have evaluated the inventory of radionuclides in low-level radioactive waste drums to send every year hundreds of them to the WLDC. In this presentation, we revisit the gross alpha measurement results of the drums transported to WLDC in the past few years and compare them with the concentrations of alpha emitters measured from alpha spectrometry and gamma spectrometry. This study offers an insight into the gross alpha measurement for radioactive waste regarding calibration source, self-absorption effect, composition of alpha emitters, etc.
        3.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This qualitative case study explores multilingual learners’ linguistic practices and how they are interrelated with their identities in the context of a Korean alternative school. The learners are two Chosunjok, and one North Korean refugee child. The data were derived from the learners’ digital storytelling videos, semi-structured interviews, stimulated-recall interviews, and observation field notes. The data were thematically analyzed and organized using Rose’s (2007) sites of visual meaning-making structure. The findings revealed that the learners had different amounts of access to information regarding second language learning, and that they depended on the resources available within the communities they belonged to. Moreover, the participants’ levels of investment in language learning were constructed around their communities and identities. Their attitudes in language learning were also interrelated with the broader English language ideologies in South Korea. By sharing the stories of three multilingual learners, the study provides pedagogical implications on the influence of resources on multilingual learners’ language learning. We emphasize the importance of providing a space for multilingual learners to critically reflect on current and future resources, utilize their full communicative repertoire, and identify ways to increase their affordances of learning.
        8,900원
        5.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The decommissioning of nuclear facilities produces various types of radiologically contaminated waste. In addition, dismantlement activities, including cutting, packing, and clean-up at the facility site, result in secondary radioactive waste such as filters, resin, plastic, and clothing. Determining of the radionuclide content of this waste is an important step for the determination of a suitable management strategy including classification and disposal. In this work, we radiochemically characterized the radionuclide activities of filters used during the decommissioning of Korea Research Reactors (KRRs) 1 and 2. The results indicate that the filter samples contained mainly 3H (500–3,600 Bq·g−1), 14C (7.5–29 Bq·g−1), 55Fe (1.1– 7.1 Bq·g−1), 59Ni (0.60–1.0 Bq·g−1), 60Co (0.74–70 Bq·g−1), 63Ni (0.60–94 Bq·g−1), 90Sr (0.25–5.0 Bq·g−1), 137Cs (0.64–8.7 Bq·g−1), and 152Eu (0.19–2.9) Bq·g−1. In addition, the gross alpha radioactivity of the samples was measured to be between 0.32–1.1 Bq·g−1. The radionuclide concentrations were below the concentration limit stated in the low- and intermediatelevel waste acceptance criteria of the Nuclear Safety and Security Commission, and used for the disposal of the KRRs waste drums to a repository site.
        4,300원
        6.
        2022.10 구독 인증기관·개인회원 무료
        Combustion method has been widely used in the analysis of 3H and 14C in various types of radioactive wastes since X. Hou reported the analysis of 3H and 14C in graphite and concrete for decommissioning of nuclear reactor. In this work, it was demonstrated that the validation result of combustion method for the simultaneous analysis of 3H and 14C in non-combustible radioactive wastes. To validate the combustion method, 3H and 14C spiked to sea sand and soil were prepared and each simulated sample was combusted with the accordance to a combustion temperature program. The validation of combustion method was assessed by the radioactivity recovery, radioactivity deviation, and relative standard deviation of measured radioactivity. The results of radioactivity recovery, radioactivity deviation, and relative standard deviation of 14C were 100~105%, less than 7%, less than 5%, respectively. In addition, 3H showed about 90% of radioactivity recovery, less than 20% of radioactivity deviation, and less than 5% of relative standard deviation. It will be provided that the validation results of combustion method in detail.
        8.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Upgraded activated carbons (ACs) are typically synthesized by mixed methods, such as solid–solid mixing and wet impregnation of low-grade ACs with KOH. This study compares the properties of upgraded ACs prepared by different methods using elemental analysis, X-ray photoelectron spectroscopy, N2 adsorption isotherms, and X-ray diffraction. In ACs produced by the solid–solid mixing, the ratio of potassium activator is proportional to the surface area and amount of gas produced. However, in wet impregnated ACs, the potassium ratio exhibits a zero or negative correlation. It is demonstrated that potassium ions in solution are not transferred to K2O and do not contribute to the surface area and pore size, generating less amount and different composition of gases. As such, impregnated ACs exhibit similar surface areas and large pores, regardless of the potassium ratio. The physical properties, such as specific surface areas and pore size distribution, of ACs using wet impregnation were similar to the ACs generated by the water physical activation. It indicated that the KOH does not efficiently act as a chemical activator in the wet impregnation method. Therefore, a certain amount and suitable mixing method of chemical activator play an important role in the property upgrade of ACs.
        4,000원
        9.
        2020.12 KCI 등재 구독 인증기관·개인회원 무료
        시설토마토에서 사전에 해충밀도를 예찰 하지 않고 작물 정식과 동시에 적용한, 기생성/포식성 천적과 그들의 먹이원/서식처가 결합되어 있는, ‘Natural Enemy in First (NEF)’ 기술의 총채벌레와 진딧물 방제효과를 확인하였다. 처리 후 12주차에 NEF 처리구에서 총채벌레 밀도억제 효과는 천적처리구 및 관행방제구에 비해 각각 32%와 82% 더 높았다. 처리 후 진딧물의 밀도는 모든 처리구에서 낮게 유지되어 처리구간 유의성 있는 차이를 확인할 수 없었다.
        11.
        2019.12 KCI 등재 구독 인증기관·개인회원 무료
        해충의 예찰 없이 작물 정식 초기에 천적을 먼저 적용할 수 있는 천적-서식처 혼합적용(Natural Enemy in First; NEF)기법의 방제효과를 확인하였다. 시설 딸기에서 조사 12주차에 NEF처리구와 천적 단독 처리구에서 친환경자재 처리구 대비 각 83%, 70%의 점박이응애 밀도 억제효과를 확인할 수 있었다. 또한 예찰 없이 작물 정식 초기에 NEF를 적용한 처리구에서 천적 단독 처리구보다 3배 이상의 높은 천적 밀도를 확인하였다.
        12.
        2019.04 구독 인증기관·개인회원 무료
        Biological control is becoming an increasingly important part of integrated pest management programs in Korea. For this reason, effective and sustainable insect pest management is a priority for many growers. And the success of biological control depends upon the use of the economical methods such as a combination of proper natural enemies and plants (banker, habitat, trap, companion, etc.). For the last nine years, we have developed simple and reliable new habitat plants system with natural enemies, and named it『Natural Enemy in First Method』that we are introducing here. Our goal was to better understand the potential for effective use of beneficial insects and their habitat plants for the management of thrips, spider mites, and aphids in greenhouses. This approach is being developed to improve biological control in various crops in Korea.
        13.
        2019.04 구독 인증기관·개인회원 무료
        The black cutworm, Agrotis ipsilon (Hufnagel, 1766) is a cosmopolitan pest that poses an economic threat to many crops such as pepper, corn, perilla, etc. A. ipsilon can be mass reared by providing Chinese cabbage, Brassica rapa under 60~70%, 16L:8D and 25±1℃ in laboratory. This study presents the mass rearing methods and the morphological characteristics of the immature stages of A. ipsilon including descriptions of the each immature stages.
        14.
        2018.10 구독 인증기관·개인회원 무료
        본 연구는 지속가능한 유기농업의 실천을 위하여 국내 작부체계와 농업환경에 적합한 한국형 현장적용 기법을 구축하고자 수행하였다. 본 연구의 기본 개념은 ‘Natural Enemy in First (NE가 먼저)’로 해충발생시기의 예찰 없이 주 작물을 정식함과 동시에 천적과 보조식물을 혼합 적용해서 해충발생 이전에 천적을 포장에 먼저 정착시키는 생물적 방제기법이다. 시설재배 딸기에서 칠레이리응애, 사막이리응애, 콜레마니진디벌과 천적의 서식처 3종을 주 작물의 정식과 동시에 적용한 결과, 관행방제구에 비해 80%이상의 해충 밀도억제효과를, 천적 단독처리구에 비해 3배 이상의 높은 천적의 밀도를 확인할 수 있었다. 또한 포장 환경과 천적의 방사방법에 구애받지 않고 천적의 해충 방제효과를 극대화시킬 수 있는 라인을 적용한 결과, 약제와 천적 혼합처리구에서 라인을 적용하지 않은 처리구에 비해 해충의 밀도가 급격히 감소하고, 천적의 밀도는 2배 이상 높게 유지되는 것을 확인할 수 있었다.
        15.
        2018.10 구독 인증기관·개인회원 무료
        The turnip sawfly, Athalia rosae is one of the main pests that damage the leaves of cabbage, radish and other cruciferous crops. The developmental biology and morphological characteristics of the immature stages of Athalia rosae were studied in the laboratory using host plant, Chinese cabbage, Brassica rapa var. glabra. A. rosae can be mass reared in laboratory throughout the year under RH 60~70%, 16L:8D and 25±1℃. This species has six larval stages in the female and five larval stages in the male. The developmental period is about 28~29 days. Ovipositional periods and larval developmental periods were 6, 9 days, respectively. The pupal period was about 14 days. Illustrations and descriptions of the various immature stages and their behaviors are provided.
        16.
        2018.10 구독 인증기관·개인회원 무료
        상주는 귀농 도시이자 농업 중심 도시로써 농업기술원을 유치할 만큼 생태학적 연구가치가 있는 친환경 도시이다. 특히 경천섬은 낙동강 본류에 있는 상주보 인근에 위치하고 있어 낙동강 생태 환경 연구의 중요 지역 중 하나이다. 하지만, 아직 경천섬에 대한 생물다양성 연구가 부족한 상태이다. 섬과 산지의 생태환경이 다르기 때문에 생물의 다양성도 다를 것이라 간주하고, 경천섬 주변의 생태학적 가치를 재조명할 기초자료를 조사하고자 한다. 이에 경천섬과 인근에 위치한 청룡사 길목 산지에 서식하는 곤충 채집을 통해 생물다양성을 조사하여 비교분석하는 것을 목적으로 한다. 채집방법은 직접잡기, 쓸어잡기, 함정트랩, 흡충관을 이용하였으며, 함정트랩에 사용된 유인제는 소주1.8ℓ와 빙초산350㎖를 혼합하여 사용하였다. 2018년 4월~8월 중 3회 채집과정을 수행하여 목표개체수를 확보하였고, 채집된 곤충은 에탄올을 채운 conical tube에 넣어 냉동실에 보관하여 보존성을 높였다. 채집과정에서 잡은 곤충들을 건조시키고 유사종끼리 분류하고 동정하는 과정을 거쳐 다양도지수, 우점도지수, 종풍부도지수, 종균등도지수, 유사도지수를 계산할 것이다. 기존에 알려지지 않았던 경천섬 일대의 생물다양성을 세세하게 분석하는 과정을 통해 경천섬의 생태학적 가치를 드러내고, 경천섬 일대의 자연환경관리와 보존에 필요한 정보나 체계적인 관리체계를 구축할 기초자료를 제공하고자 한다.
        17.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        온라인 게임의 인기와 이용자 수가 늘면서, 경쟁에서 이기기 위해 불법 프로그램을 사용하는 부정행위자의 수도 늘고 있다. 본 연구는 인기 FPS 게임인 배틀그라운드의 로그 데이터와 해당 게임의 퍼블리싱을 맡은 카카오게임즈가 공개한 부정행위자 정보를 수집하여, 부정행위자가 게임 상에서 어떻게 행동하고 다른 플레이어들과 어울리는지 확인하였다. 부정행위자는 다른 플레이어로부터 배제되거나, 제재를 피하기 위해 소극적으로 활동할 것처럼 보일 수 있다. 하지만 데이터 분석 결과, 부정행위자는 정상 이용자보다 더 활발하게 게임을 이용하고 있으며 특히 팀플레이 모드를 선호하는 것으로 나타났다. 또한 부정행위자는 정상 이용자보다 더 많은 친구를 가지고 있었다. 부정행위자가 일부러 다른 플레이어와의 불화와 갈등을 야기한다는 측면을 제시한 선행 연구와 달리, 본 연구는 부정행위자가 팀 내에서 정상 이용자에 비해 더 많은 기여를 하고 있는 점 역시 발견하였다. 본 연구가 밝힌 온라인 게임 부정행위자의 특성은 부정행위 대응 방안 수립 시 참고할 수 있을 것이며, 다른 온라인 커뮤니티의 반사회적 행위자 특성을 파악하는 데에도 도움을 줄 수 있을 것이다.
        4,000원
        18.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to identify the effect of upper thoracic mobilization on cervical alignment in stroke patients with forward head posture. The subject's of this study were two stroke patients with forward head posture and a cervical curve angle (four-line Cobb's method; FLCM) less than 40°. The intervention, central posterior-anterior (PA) mobilization, was applied to the T1-T4 vertebrae (upper thoracic spine) following the Maitland concept. This mobilization was applied three times per week for four weeks. In the results, the cervical curve angle (FLCM) increased for both subject 1 and 2. However, Jochumsen method score was decreased in subject 1, while it was increased in subject 2. These results demonstrate that upper thoracic mobilization had the positive effect on the cervical curve angle but not on Jochumsen method score. These findings suggest that PA mobilization on the upper thoracic spine could correct cervical curve angle measured by FLMC in stroke patients with FHP.
        3,000원
        19.
        2018.04 구독 인증기관·개인회원 무료
        The citrus flatid planthopper Metcalfa pruinosa, a invasive species causes serious damages to field crops, including sweet persimmon, soybean, maize, especially ginseng (Panax ginseng C.A meyer). We selected six chemical pesticides and one environmental friendly pesticide made from the mixture of derris extracts, citronella oils, and cinnamon extracts in laboratory. These pesticides showed over 90% of control effect in open ginseng field. This study was carried out with the support of the cooperative research program for RDA (project No. PJ0124992018), Republic of Korea.
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