검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 563

        61.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Comparisons between bare carbon (CPs) and nitrogen-doped carbon nanoparticles (N-CPs) synthesised using hydrothermal reaction are carried out. It was found that hydrothermal reaction of citric acid yields graphene-like sheets, while the nitrogen doping using ethylenediamine resulted in amorphous polymeric ball-like hydrocarbons devoid of any aromatic rings. Although the Fourier transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy indicate the presence of carbon–carbon double bonds (C=C), and the ground states of both materials are very deep (> 7.8 eV) as measured by ultraviolet photoelectron spectroscopy. This indicates the conjugation is very short. This is supported by the fact that both materials are UV blue emitting peaking at 375 nm probably originating from C=C.
        4,000원
        62.
        2019.06 구독 인증기관 무료, 개인회원 유료
        The IMO Standard Marine Communication Phrases (SMCP) has been established purposely to enhance the greater safety of vessel’s navigation by standardizing the language used among seafarers. However, accidents are still occurred due to communication failures among onboard merchant vessels’ crews. It is worth mentioning that the major cause of marine accidents is human error (80%) where one-third from it was due to communication failures. Ineffective communication, different culture and language among seafarers onboard are some instigators of human error that lead to accidents in marine operations. Therefore, the primary aim of this paper is to investigate and evaluate the causal factors that contributes to communication failures onboard merchant vessels. Then, this paper recommends possible solutions for minimizing the communication failures among seafarers. To achieve this research objectives, two decision-making tools which are the Analytical Hierarchy Process (AHP) and Evidential Reasoning (ER) was applied. Data and judgments are obtained from domains experts from four marine training providers and eight shipowners in Malaysia. The result has shown that lack of SMCP knowledge, prejudice and dialect varieties are the most significant factors that contribute to the communication failures onboard merchant vessels. Few suggestions and opinions from the experts are proposed in this paper. This research can assist marine training providers and shipowners to identify and evaluate the causal factors of communication failures thus corrective action can be taken.
        4,200원
        67.
        2019.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The paper presents the results of a multi-criteria comparative evaluation of 12 feasible Russian nuclear energy deployment scenarios with thermal and fast reactors in a closed nuclear fuel cycle. The comparative evaluation was performed based on 6 performance indicators and 5 different MCDA methods (Simple Scoring Model, MAVT / MAUT, AHP, TOPSIS, PROMETHEE) in accordance with the recommendations elaborated by the IAEA/INPRO section. It is shown that the use of different MCDA methods to compare the nuclear energy deployment scenarios, despite some differences in the rankings, leads to well-coordinated and similar results. Taking into account the uncertainties in the weights within a multi-attribute model, it was possible to rank the scenarios in the absence of information regarding the relative importance of performance indicators and determine the preference probability for a certain nuclear energy deployment scenario. Based on the results of the uncertainty/sensitivity analysis and additional analysis of alternatives as well as the whole set of graphical and attribute data, it was possible to identify the most promising nuclear energy deployment scenario under the assumptions made.
        4,300원
        68.
        2018.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Less mature nuclear reactor technologies are characterized by a greater uncertainty due to insufficient detailed design information, operational data, cost information, etc., but the expected performance characteristics of less mature options are usually more attractive in comparison with more mature ones. The greater uncertainty is, the higher economic risks associated with the project realization will be. Within a comparative evaluation of less and more mature nuclear reactor technologies, it is necessary to apply economic risk measures to balance judgments regarding the economic performance of less and more mature options. Assessments of any risk metrics involve calculating different characteristics of probability distributions of associated economic performance indicators and applying the Monte-Carlo method. This paper considers the applicability of statistical risk measures for different economic performance indicators within a trial case study on a comparative evaluation of less and more mature unspecified LWRs. The presented case study demonstrates the main trends associated with the incorporation of economic risk metrics into a comparative evaluation of less and more mature nuclear reactor technologies.
        4,000원
        70.
        2018.12 구독 인증기관 무료, 개인회원 유료
        This study investigated the management of staff training programmes and school climate for teacher retention in secondary schools in Rivers State. Two (2) research questions and 2 corresponding hypotheses were answered and tested in the study, respectively. The population of the study comprised all the 268 public senior secondary schools in Rivers State, with 268 principals (218 males and 50 females), from which a sample of 215 (80%) was drawn using the stratified random sampling technique. Respondents of the study responded to a validated 20 – item instrument titled ‘Managing Staff Training Programmes and School Climate for Teacher Retention Scale’ (STPSCTRS), designed by the researchers, in the modified 4 – point likert scale model, with a reliability index of 0.74, obtained using Cronbach Alpha. In all, 215 sets of the instruments were administered to the respondents in their various schools 214 (99%) were retrieved, while 213 (99%) survived after coding and were used in the statistical procedures. Mean and standard deviation, were used in answering the research questions, while z-test was used in testing the hypotheses at 0.05 alpha level. Results from data analysis show that staff training programmes, and school climate are necessary for teacher retention. It was concluded that the use of staff training programmes and conducive school climate to a very high extent, determine teacher retention in secondary schools in Rivers State. Recommendations were that school principals, government and educational stakeholders should give attention to staff training programmes and school climate in their various schools.
        4,600원
        79.
        2018.10 구독 인증기관·개인회원 무료
        Deimatic display 는 평상시에는 위장으로 자신을 보호하는 동물들이 포식자에게 위협당하였을 때에만 일시적으로 화려한 경고색을 보여줌으로써 포식자를 놀라게 하여 자신을 보호하는 방어전략이다. 본 연구에서는 3가지의 서로 다른 연구 방법을 이용하여 이 방어전략의 진화에 대해 연구하였으며, 연구의 모델로는 태극나방과 (Erebidae)의 나방을 이용하였다. 첫 번째로 deimatic display 전략이 어떤 종에서 진화하였으며, 이 전략이 동물의 몸 크기와 함께 진화하였는지를 계통수 분석을 이용한 방법으로 연구하였다. 연구 결과 deimatic display 는 몸 크기가 상대적으로 큰 곤충에서 선택적으로 진화하였다는 사실을 발견하였다. 두 번째로 deimatic display 전략이 왜 body size 가 큰 종에서 진화하였는지를 이론적으로 검증하기 위하여 수학적 모델링을 활용, deimatic display 와 몸 크기와의 이론적인 관계를 연구하였다. 이론적 모델링이 시사하는 바는 1) 몸 크기가 클수록 위장이 실패할 확률이 높으며, 2) 몸 크기가 클수록 deimatic display 가 포식자를 위협하는 효과가 클수록 이러한 진화적인 관계가 생성될 수 있다는 점을 발견하였다. 마지막으로 수학적 모델링에서 도출된 결과를 실험적으로 검증하기 위하여 로보틱스 기술을 활용, deimatic display 행동을 보이는 인공나방로봇을 제작하였다. 제작된 인공나방 로봇의 날개크기와 날개색채를 변화시켜가며 나방의 크기가 커질수록 deimatic display 전략이 포식자(조류)를 위협하는데 더 효과적인지를 테스트하였으며, 실험 결과 deimatic display 전략은 나방의 사이즈가 클수록 더 효과적이라는 사실을 입증하였다. 추가 연구 결과 이러한 큰 크기 – 숨겨진 화려한 색채의 관계는 태극나방과 뿐만이 아니라 메뚜기목, 대벌레목, 사마귀목, 그리고 누에나방과(나비목)에서도 발견됨을 확인하였다. 본 연구의 결과는 deimatic display 전략이 큰 크기와 공진화하였음을 보여주며, 이러한 크기-색채 공진화는 deimatic display 전략의 효용성과 밀접한 관련을 가지며 이루어졌다는 사실을 보여준다.
        80.
        2018.10 구독 인증기관·개인회원 무료
        We investigated the detoxification strategies of Helicoverpa armigera and Heliothis virescens, which allow them to feed successfully on cotton plants that produce toxic gossypol as a chemical defense compound. First, we tested CYP6AE14, a proposed candidate enzyme for gossypol detoxification, for its ability to detoxify gossypol. In incubation assays with gossypol and heterologously expressed CYP6AE14 no metabolites were detected. Our data show that CYP6AE14 is not directly involved in gossypol metabolism, at least under the assay conditions tested, but rather takes part in the general stress response of the herbivores to plant toxins. Second, we discovered that H. armigera and H. virescens excrete a large proportion (50%) of unmetabolized gossypol in the feces, but additionally metabolize gossypol by glycosylation. Analysis of larval feces revealed three monoglycosylated and up to five diglycosylated gossypol isomers when larvae fed on gossypol-supplemented diet. Based on their expression patterns we selected H. armigera candidate UGT genes and functionally expressed the respective proteins in insect cells. In enzymatic assays, we showed that UGT41B3 and UGT40D1 are capable of glycosylating gossypol mainly to a diglycosylated gossypol isomer that is characteristic for H. armigera and is absent in H. virescens feces. We offer novel insights into the detoxification mechanism of the plant defensive toxin, gossypol, by two generalist herbivores.
        1 2 3 4 5