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        검색결과 342

        1.
        2024.04 구독 인증기관·개인회원 무료
        Climate change has led to increased insect pests and pest distribution changes. Traditionally, chemical control using synthetic pesticides has been the main method for pest management, but the emergence of pesticide-resistant pests has become a problem. There is a need to develop new pest control agents to overcome these issues. Entomopathogenic fungi used in pest management have minimal environmental side effects and possess a mechanism of action distinct from that of synthetic pesticides. However, there is a need for the development of technologies to maximize the insecticidal effects of fungi against pests, and expressing and releasing dsRNA within the fungi can preemptively knock out the activation of the insect’s defense system, thereby enhancing the insecticidal effect. Controlling insect defense genes and using entomopathogenic fungi as bio-carriers forms a new pest management strategy. This approach, described as a “microbial insecticide agents development strategy of cassette concept, ” can versatilely modify genes and microbes. It is expected to overcome the limitations of synthetic pesticides.
        2.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 거리화단 화훼경관 조성 전·후의 스트레스 변화 를 알아보기 위하여, 순창 소재의 경찰관 총 18명을 대상으로 타액 채취 및 설문조사를 실시하였다. 생리 측정은 타액 코르 티솔, 혈압, 심리 측정은 식물 재배 활동 수준, 스트레스수준, 거리화단 화훼경관에 대한 간이 SD 감성을 측정하였다. 타액 코르티솔, 혈압의 사전/후 비교는 대응표본 t-test, 타액 코르 티솔, 혈압의 성별에 따른 집단간 사전/후 비교는, 독립표본 t-test, 스트레스수준, 간이 SD는 윌콕슨 부호 순위 검정 등으 로 분석하였다. 화훼경관 조성 전보다 조성 후 총 코르티솔 수 치가 낮아졌고, 식물 재배 활동 수준은 높아졌으나 통계적 유 의성은 없었다. 혈압은 여자의 경우 거리화단 화훼경관 조성 전과 조성 후 모두 정상 혈압이었고, 남자의 경우 거리화단 화 훼경관 조성 전 고혈압 전단계에서 조성 후 주의혈압으로 낮 아지는 긍정적 효과가 있었다. 거리화단 화훼경관 조성 전·후 의 스트레스수준을 총 4단계(총 4단계: 단계가 높을수록 스트 레스가 높은 수준임)로 문항 전체의 총합 수치로 알아본 결과, 화훼경관 조성 전에는 4단계(50.0%), 2단계(38.9%), 3단계 (11.1%) 순이었으나, 조성 후에는 4단계(44.5%), 2, 3단계(각 22.2%), 1단계(11.1%) 순으로 거리화단 화훼경관 조성 전에 는 1단계(정상적인 스트레스 상태로 스트레스요인 자체가 심 각하지 않거나 좋은 스트레스로 받아들인 경우)가 0%에서 조 성 후 11.1%로 높아졌다. 화훼경관 조성 전·후 SD법을 이용 하여 쾌적감, 자연감, 그리고 진정감에 대해 평가한 결과, 화 훼경관 조성 후 쾌적감, 자연감, 진정감이 높은 것으로 나타났 다(p<.05). 거리화단 화훼경관에 따른 식물 재배 활동 수준과 주요 변수간의 상관관계를 알아본 결과, 화훼경관 조성 후 식 물 재배 활동 수준과 스트레스수준, 스트레스수준과 진정감은 부(-)의 상관관계, 식물 재배 활동 수준과 쾌적감, 자연감, 진정 감과는 0.5 이상의 높은 정(+)의 상관관계가 있었다(p<.05). 따라서 식물 재배 활동 수준이 높아질수록 쾌적감, 자연감, 그 리고, 진정감은 높아지고, 거리화단 화훼경관이 없는 공간보 다 화훼경관이 있는 공간에서 쾌적감, 자연감, 그리고 진정감 을 더 크게 느끼는 것으로 판단되었다. 본 연구에서 거리화단 화훼경관을 통하여 고위험군의 높은 스트레스는 줄여주고 식 물에 대한 흥미, 관심과 심리적 안정효과는 높여 줄 수 있는 유용한 가능성이 있을 것으로 생각되었다.
        4,500원
        3.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한국어 학습자들이 자신들의 언어학습 신념이 그들의 전반 적인 언어학습과 새로운 환경에 적응하는 것에 어떠한 관계가 있는지를 찾기 위함이 목적이다. 여섯 명의 한국대학교에 재학 중인 외국인 유학 생들을 대상으로 그들의 언어학습 신념에 대한 인터뷰가 진행되었다. Horwitz의 BALLI 문항을 기반으로 한 반구조적 인터뷰가 진행되었으며, 그들의 답변은 외국어 능력, 언어학습의 어려움, 언어학습의 본성, 학습 과 소통전략, 동기와 기대 등의 주제를 기반으로 비슷한 패턴을 보이는 항목별로 구분되어졌다. 연구 결과는 외국인 유학생들은 그들의 한국어 실력이 향상될수록 자신감을 가졌으며, 그들은 문화에 대한 학습이 언어 학습에 중요한 부분이라는 것을 인지했다. 또한, 가장 효과적인 학습법은 실제적인 상황과 사람들과 어울리는 것을 꼽았으며, 그들은 대학 졸업 이후에도 한국에 남아 있기를 희망했다.
        7,000원
        4.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since rice is the main food in Korea, there are no regulations on corn milling yet. Corn is known as one of the world's top three food crops along with wheat and rice, and it is known that 3.5 billion people worldwide use corn for food. In addition, corn mills are not developed or sold in Korea, but the use of corn mills is increasing significantly in many countries in Southeast Asia. In the Philippines, as Korea's rice mill import increases, Korea's KAMICO (Korea Agricultural Machinery Industry Cooperative) and domestic company A agreed to develop a corn mill jointly with PHilMech, an organization affiliated with the Philippine Ministry of Agriculture. However, research on corn milling was very insignificant, so the development was carried out based on the technology of Korea's rice mill. Rice milling is performed by peeling off the skin of rice and producing brown or white rice, so it is carried out by removing the skin and cutting the skin. On the other hand, in the corn mill, the skin of the corn is peeled, pulverized and selected to produce main products suitable for edible use. Therefore, in order to develop a corn mill, processes such as peeling, transfer, grinding, sorting, and by-product separation are required, and suitable parts must be developed. In addition, the performance must be gradually improved through experiments in which corn is repeatedly milled. The Philippines produces 7.98 million tons/year of corn, which is about 100 times that of Korea, and is mostly consumed as a staple food. This is about 10% of the total crop production in the Philippines. In addition, the main cultivation complexes of corn are the mountainous regions of Tarlac or Pangasinan, and the produced corn is 72.4% of the so-called yellow corn called Arabel and Sarangani, and the remaining 27.6% are known as white corn. In this study, it was intended to produce grains of 2.5 mm or less suitable for food for yellow corn and to develop a corn mill for 200 kg per hour. Detailed conditions for development are stipulated as more than 55% of the main product recovery rate, more than 31% of the by-product recovery rate, less than 5% of the raw material loss rate, and more than 80% of the embryo dislocation rate. In this study, to achieve this, the overall process of the corn mill was developed, and the optimal conditions for the corn mill were obtained through the development of parts and empirical tests to improve performance. In addition, it was intended to achieve the development goal by evaluating and analyzing the performance of each part so that it did not conflict.
        4,800원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Foot-and-mouth disease (FMD), which affects cloven-hoofed animals, is economically important because of its highly contagious nature. FMD virus (FMDV), the causative agent of FMD, involves seven serotypes (O, A, Asia1, C, and SAT 1-3). Serotype Asia1 is unique to the Asian territory and is subdivided into nine genetic groups (G-I-IX) based on nucleotide variations in the VP1 sequence. Asia1 Shamir, the most representative Asia1 vaccine, is not highly protective against the Asia1/MOG/05 (G-V) lineage found in North Korea in 2007. Therefore, we investigated whether a chimeric virus strain (Asia1/MOG/Shamir), in which the VP4, VP2, and VP3 sequences of Asia1/MOG/05 were combined with the VP1 sequence of Asia1 Shamir, can simultaneously protect against both viruses. We determined the optimal viral growth conditions for the commercial utilization of this chimeric virus strain. Of the three types of cell culture media, the Cellvento medium resulted in the highest amount of antigen in the samples. The chimeric strain was proliferated in a small bioreactor to produce a test vaccine, and its immunogenicity was evaluated in pigs. The virus neutralization (VN) titer against the Asia1 Shamir virus was > 1/100 after the second immunization with the chimeric vaccine in pigs. In addition, a single dose of the test vaccine resulted in a VN titer of > 1/100 against the Asia1/MOG/05 strain. Taken together, our chimeric vaccine strain provided sufficient protection against the Asia1/MOG/05 and Asia1 Shamir viruses, suggesting its potential as a novel vaccine for both these strains.
        4,000원
        6.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explores the perceptions of Chinese engineering-major students towards their English learning experience after taking a mandatory English composition course in an EMI college. The investigation centers on first-year students’ perceptions of transitioning to EMI, with a focus on how the composition course has assisted students’ transition as a primary language support. Data were collected through a metaphor elicitation technique in which students expressed their perceptions of English learning, complemented by a thematic analysis of 86 reflection essays on the composition class. An analysis of the 334 metaphors identified students’ enhanced confidence in English, the importance of the English-using environment, positive views of learning communities, and increased agency in the learning process. It also revealed that many students were stressed and unaware of learning strategies, therefore suggesting institutional-level language support. One implication is to promote the culture of the learning community. The findings can be particularly useful for programs that are implementing language support for non-English major students.
        6,100원
        10.
        2023.11 구독 인증기관·개인회원 무료
        KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.
        11.
        2023.11 구독 인증기관·개인회원 무료
        Natural analogue studies aim to understand specific processes or to make predictions regrading formation processes or environmental conditions based on information from natural phenomena on Earth. Studying geological environments similar to the disposal system can help evaluate the longterm stability of the disposal system. These studies play a crucial role in evaluating the long-term stability of deep geological repositories (DGRs) for high-level radioactive wastes, which must remain stable for extended periods. In particular, bentonite, as a vital buffer material in DGRs, is mainly composed of montmorillonite and undergoes a transformation into zeolite under specific environmental conditions, resulting in the loss of its role as a buffer material in terms of swelling property and hydraulic conductivity. In this study, bentonite samples from Pohang Basin in Korea were investigated, revealing the presence of montmorillonite and zeolite in both outcrop and drilling core samples. While it has been known that montmorillonite and zeolites can form from volcanic glass through diagenesis or hydrothermal alteration, this study revealed that these minerals are formed under distinct environmental conditions. The outcrop samples primarily consisted of montmorillonite with minor quantities of cristobalite and amorphous silicate minerals. In contrast, the drilling core samples were composed of montmorillonite, zeolites, quartz and feldspar, indicating different mineral assemblages and characteristics between the outcrop and drilling samples. This observation suggests different environmental conditions during the mineral formation process. Therefore, various experiments and analytical methods were employed to gain a deeper understanding of the phase transformation from montmorillonite to zeolites under diverse environmental conditions
        12.
        2023.11 구독 인증기관·개인회원 무료
        The solid-state chemistry of uranium is essential to the nuclear fuel cycle. Uranyl nitrate is a key compound that is produced at various stages of the nuclear fuel cycle, both in front-end and backend cycles. It is typically formed by dissolving spent nuclear fuel in nitric acid or through a wet conversion process for the preparation of UF6. Additionally, uranium oxides are a primary consideration in the nuclear fuel cycle because they are the most commonly used nuclear fuel in commercial nuclear reactors. Therefore, it is crucial to understand the oxidation and thermal behavior of uranium oxides and uranyl nitrates. Under the ‘2023 Nuclear Global Researcher Training Program for the Back-end Nuclear Fuel Cycle,’ supported by KONICOF, several experiments were conducted at IMRAM (Institute of Multidisciplinary Research for Advanced Materials) at Tohoku University. First, the recovery ratio of uranium was analyzed during the synthesis of uranyl nitrate by dissolving the actual radioisotope, U3O8, in a nitric acid solution. Second, thermogravimetric-differential thermal analysis (TG-DTA) of uranyl nitrate (UO2(NO3)2) and hyper-stoichiometric uranium dioxide (UO2+X) was performed. The enthalpy change was discussed to confirm the mechanism of thermal decomposition of uranyl nitrate under heating conditions and to determine the chemical hydrate form of uranyl nitrate. In the case of UO2+X, the value of ‘x’ was determined through the calculation of weight change data, and the initial form was verified using the phase diagram for the U-O system. Finally, the formation of a few UO2+X compounds was observed with heat treatment of uranyl nitrate and uranium dioxide at different temperature intervals (450°C-600°C). As a result of these studies, a deeper understanding of the thermal and chemical behavior of uranium compounds was achieved. This knowledge is vital for improving the efficiency and safety of nuclear fuel cycle processes and contributes to advancements in nuclear science and technology.
        13.
        2023.11 구독 인증기관·개인회원 무료
        Safeguards systems and measures are determined through diversion scenario analysis based on the facility design information submitted to the IAEA when a new nuclear facility is introduced. While the concept of safeguards-by-design (SBD), which considers the safeguards from the design phase for a facility operator to minimize unplanned changes or disruption to facility operations as well as for the IAEA to increase the efficiency and effectiveness in safeguards implementation, has been emphasized for more than a decade, there is no practical tool or guidance on how to apply it. In this study, we develop a diversion path analysis tool and introduce how to apply SBD using it. A diversion path analysis tool was developed based on the elements that constitute diversion and the algorithm generated based on the initial information of facility and nuclear material flow. The results of utilizing the analysis tool depending on a different level of facility information and the safeguards set-ups were compared through examples. Taking a typical light water reactor as an example, the test analyzed the automatic generation of dedicated routes, configuration of safeguards measures, and diversion path analysis. Through this, the application and limitations of the analysis tool are discussed, and ideas for utilization according to the SBD concept and necessary regulatory guidance are proposed. The results of this study are expected to be directly utilized to domestic nuclear control during the regulation process for a construction of new nuclear power systems, and furthermore, to enhance national credibility in the engagement with the IAEA for implementation of safeguards.
        14.
        2023.10 구독 인증기관·개인회원 무료
        아메리카동애등에(H. illucens)는 음식물 폐기물 등 유기성 폐자원을 효율적으로 처리할 수 있는 능력을 가지 고 있어 전세계적으로 주목받고 있는 환경정화 곤충이다. 하지만 유기성 폐자원을 처리 시 가장 큰 문제는 아메리 카동애등에가 먹이인 유기성 폐자원을 소화시킬 때 발생되는 악취이다. 국내에서 현재 아메리카동애등에를 사육하고 있는 농가는 223호로 조사되고 있지만 이중 악취발생 저감장치 등을 설치한 농가는 10%가 안되는 것으 로 생각된다. 따라서 국내에서 동애등에 먹이로 가장 많이 사용되는 습식사료를 먹이로 사용하였을 때 농가 사육 장 안에서 발생되는 복합악취와 지정악취 22종에 대하여 분석하였다. 그 결과, 복합악취는 249배였으며, 지정악 취는 22종 중 7종(암모니아, 메틸메르캅탄, 트라이메틸아민, 아세트알데하이드, 프로피온알데하이드, 뷰틸알 데하이드, i-발레르알데하이드)가 검출되었다. 이중 가장 높은 농도를 나타낸 악취물질은 암모니아로 98.4ppm 이 분석되었다. 또한, 아메리카동애등에를 사육 시 가장 많이 발생되는 암모니아의 발생시기는 사육초기인 1~4 령보다 5령 이후 전생육기 중의 대부분을 발생시키는 것으로 조사되었다. 이러한 결과는 암모니아 저감을 위한 적정시기를 설정하는데 도움이 될 것으로 생각된다.
        15.
        2023.10 구독 인증기관·개인회원 무료
        최근 이식에 강하고 도심 환경에서의 스트레스에 강한 저항성을 지니고 있으며 병해충이 많이 없는 것으로 알려진 대왕참나무가 가로수 및 조경수로 많이 식재되고 있다. 하지만 대왕참나무의 식재량이 증가하면서 일부 지역에서 해충 피해가 보고되고 있고 이들에 대한 관리 대책 마련이 시급해지고 있다. 따라서 본 연구는 대왕참나 무의 식재 환경에 따른 해충 발생 양상을 조사하기 위해 수행하였다. 2022년부터 2023년 동안 7~8월 중에 조사를 수행하였으며, 육안조사법과 고지 가위를 활용하여 줄기와 잎에서 해충의 종별 개체수를 조사하였다. 대왕참나 무의 식재 환경은 도로변과 공원으로 구분하였고, 서울, 성남, 춘천, 원주, 여수, 함안, 창원 지역을 대상으로 진행 하였다. 조사 결과 총 20과 34종 1,126개체가 관찰되었으며 그 중 가로수에서 15과 18종 699개체가 관찰되었고 공원 지역에서 17과 27종 427개체가 관찰되었다. 가로수에서 나비목과 노린재목 해충이 더 많았으며 공원에서는 딱정벌레목 해충이 더 많았다.
        16.
        2023.05 구독 인증기관·개인회원 무료
        To evaluate the safeguards system or performance in a facility, it is crucial to analyze the diversion path for nuclear materials. However, diversion paths can range from the extremely simplified to the complicated depending on the level of knowledge and the specific person conducting the analysis. This study developed the diversion path analysis tools using an event tree and fault tree method to generating diversion paths systematically. The essential components of the diversion path were reviewed, and a logical flow was developed for systematically creating the diversion path. An algorithm was created based on the facility design components and logical flow, as well as the initial information of the nuclear materials and material flows. The event tree and fault tree analysis tools were used to test the path generation algorithm. The usage and limitations of these two logic methods are discussed, and ideas to incorporate the logic algorithm into practical program tools are suggested. The tests were analyzed on a typical light water reactor as an example, including automatic generation of dedicated pathways, configuration of safeguards measures, and analyzing paths with strategies for avoiding safeguard systems. The results led to the development of a draft pathway analyzer program that can be applied to general nuclear systems. The results of this study will be used to develop a program module that can systematically generate diversion paths using the event tree and fault tree method. It can help to guide and provide practical tools for implementing SBD.
        17.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
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