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        검색결과 33

        1.
        2023.11 구독 인증기관·개인회원 무료
        KHNP is conducting research to decommission Wolsong Unit 1 Calandria. Establishment of preparation and dismantlement processes, conceptual design of equipment and temporary radiation protection facilities, and waste management are being established. In particular, the ALARA plan is to be established by performing exposure dose evaluation for workers. This study aims to deal with the methodology of evaluating exposure dose based on the calandria dismantling process. The preparation process consists of bringing in and installing tooling and devices, and removing interference facilities to secure work space. The main source term for the preparation process is the calandria structure itself and crud of feeders. In the case of the dismantlement process, a structure with a shape that changes according to the process was modeled as a radiation source. It is intended to estimate the exposure dose by selecting the number of workers, time, and location required for each process in the radiation field evaluated according to the preparation and dismantlement process. In addition, it is also conducting an evaluation of the impact on dust generated by cutting operations and the human impact of C-14, H-3, which are specialized nuclides for heavy water reactors. KHNP is conducting an exposure dose evaluation based on a process based on the preparation and dismantlement process for decommissioning Calandria through computation code analysis. If additional worker protection measures are deemed necessary through dose evaluation according to this methodology, the process is improved to prepare for the dismantling of worker safety priorities.
        2.
        2023.05 구독 인증기관·개인회원 무료
        KHNP is carrying out international technical cooperation and joint research projects to decommission Wolsong unit 1 reactor. Construction data of the reactor structures, experience data on the pressure tube replacement projects, and the operation history were reviewed, and the amount of dismantled waste was calculated and waste was classified through activation analysis. By reviewing COG (CANDU owners Group) technical cooperation and experience in refurbishment projects, KHNP’s unique Wolsong unit 1 reactor decommissioning process was established, and basic design of a number of decommissioning equipment was carried out. Based on this, a study is being conducted to estimate the worker dose of dismantling workers. In order to evaluate the dose of external exposure of dismantling workers, detailed preparation and dismantling processes and radiation field evaluation of activated structures are required. The preparation process can be divided into dismantlement of existing facilities that interfere with the reactor dismantling work and construction of various facilities for the dismantlement process. Through process details, the work time, manpower, and location required for each process will be calculated. Radiation field evaluation takes into account changes in the shape of structures by process and calculates millions of areas by process, so integrated scripts are developed and utilized to integrate input text data. If the radiation field evaluation confirms that the radiation risk of workers is high, mutual feedback will be exchanged so that the process can be improved, such as the installation of temporary shields. The results of this study will be used as basic data for the final decommissioning plan for Wolsong unit 1. By reasonably estimating the dose of workers through computer analysis, safety will be the top priority when decommissioning.
        3.
        2022.05 구독 인증기관·개인회원 무료
        Complexation of actinides and lanthanides with carboxylic organic ligands is known to facilitate migration of radionuclides from deep geological disposal systems of spent nuclear fuel. In order to examine the ligand-dependent structures of trivalent actinides and lanthanides, a series of Eu(III)-aliphatic dicarboxylate compounds, Eu2(oxalate)3(H2O)6, Eu2(malonate)3(H2O)6, and Eu2(succinate)3(H2O)2, were synthesized and characterized by using X-ray crystallography and time-resolved laser fluorescence spectroscopy. Powder X-ray diffraction results captured the transition of the coordination modes of aliphatic dicarboxylate ligands from side-on to end-on binding as the carbon chain length increases. This transition is illustrated in malonate bindings involving a combination of side-on and end-on modes. Strongly enhanced luminescence of these solid compounds, especially on the hypersensitive peak, indicates a low site symmetry of these solid compounds. Luminescence lifetimes of the compounds were measured to be increased, which is ascribed to the displacement of water molecules in the innersphere of Eu center upon bindings of the organic ligands. The numbers of remaining bound water molecules estimated from the increased luminescence lifetimes were in good agreement with crystal structures. The excitation-emission matrix spectra of these crystalline polymers suggest that oxalate ligands promote the sensitized luminescence of Eu(III), especially in the UV region. In the case of malonate and succinate ligands, charge transfer occurs in the opposite direction from Eu(III) to the ligands under UV excitation, resulting in weaker luminescence.
        6.
        2019.04 구독 인증기관·개인회원 무료
        토마토 온실에서 담배가루이 (Bemisia tabaci) 유인을 위한 작물에 따른 선호도를 조사하였다. 피망, 토마토, 오이, 가지의 4 종류의 작물을 아크릴케이지에 같이 넣어두고 담배가루이 성충 30쌍을 방사하여 선호도 및 산란수를 조사하였다. 담배가루이 성충은 오이(약 40%)와 가지(약 40%)에서 가장 선호하였으며, 토마토(10%)와 피망(10%)의 선호도는 낮았다. 기주에 따른 담배가루이의 성충 30쌍의 산란수는 오이에서 485개로 가장 높았으며 가지(250), 토마토(131), 피망(126)의 순으로 조사되었다. 토마토 온실에 가지묘를 정식하였을 경우에는 토마토에서는 주당 약 20마리의 담배가루이가 조사되었으나 가지에서는 주당 400∼500마리의 담배가루이가 조사되어 토마토 온실에서 가지를 이용한 담배가루이 유인이 가능함을 알 수 있었다.
        7.
        2018.10 구독 인증기관·개인회원 무료
        1분 간격 자동 잎면적 분석을 통해 온도에 따른 담배거세미나방 유충의 섭식과 발육을 조사하였다. 20, 25, 30℃의 세 온도에서 피망 잎을 배지에 부착하여 담배거세미나방 유충에 제공하였고 하루에 한번내지 두번 새로운 잎을 갈아주었다. 30℃에서 담배거세미나방 유충은 탈피 직후 섭식을 즉시 시작하여 1회 섭식은 10~15분 지속하고, 60~90분 간격으로 섭식을 하였다. 이러한 섭식 행동은 약 30~50시간 지속되며 탈피 직전 10~16시간 동안은 섭식이 중단되었다. 탈피 후 앞서의 섭식 패턴은 다음 영기에서 동일하게 반복되었다. 25℃에서 담배거세미나방 유충의 영기 내 섭식 기간은 약 32~53시간 지속되며 탈피 전 비섭식 기간은 16~22시간 지속되었다. 20℃에서는 영기 내섭식 기간은 60~133시간으로 크게 증가하고 비섭식 기간도 11~38시간으로 다른 온도에 비해 길어졌으며 다른 온도와 달리 7령충까지 발육하였다. 2령충에서 고치 형성 전까지의 발육 시간은 20℃에서는 39046분(27.1일)이 소요되었고 25℃에서는 17626분(12.2일), 30℃에서는 14168분(9.8일)으로 조사되었다. 각 온도별 유충의 섭식량은 영기에 따라 지수적으로 증가하였다.
        8.
        2018.04 구독 인증기관·개인회원 무료
        약제 처리에 따른 담배거세미나방(Spodoptera litura) 유충의 섭식 행동 및 반응을 조사하기 위해 1분 간격으로 잎면적을 자동 측정하였다. 담배거세미나방 유충의 섭식 행동은 섭식기와 비섭식기가 뚜렷하게 구분되었으며, 섭식기가 끝나면 비섭식기를 거쳐 탈피를 하고 다시 섭식기에 들어갔다. 1회 섭식 지속 시간은 약 15분으로 조사되었고, 영기 내 평균 섭식 회수는 약 27.5회로 섭식 지속 시간과 마찬가지로 영기에 따른 차이는 없었다. 약제 처리는 피망 잎을 Buprofezin methoxyfenozyd과 BT (Bacillus thuringiensis) 500ppm 약액에 10초간 침지 처리하였다. Buprofezin methoxyfenozyd를 처리 하였을 경우 섭식 시간은 평균 8~9분으로 감소하였고, 치사 전까지 섭식량은 각각 176mg으로 조사되었다. 하지만 BT제를 처리 시에는 담배거세미나방 유충은 치사하지 않았다.
        9.
        2017.04 구독 인증기관·개인회원 무료
        The cowpea aphid Aphis craccivora Koch (Hemiptera: Aphididae) is an important pest on several species of legumes. We investigated the development periods and survivorship of A. craccivora nymph, and longevity and fecundity of A. craccivora adult. The study was conducted at five constant temperatures of 10, 15, 20, 25, and 30°C, respectively. The lower developmental threshold (LDT) and thermal constant (K) of A. craccivora nymph stage were estimated by linear regression. Higher temperature threshold (TH) and lower temperature threshold (TL) were calculated by biophysiological model. Developmental completion of A. craccivora nymph stage was described using a two-parameter Weibull distribution model. Life table parameters were estimated by the jackknife method.
        11.
        2011.11 구독 인증기관 무료, 개인회원 유료
        바다에 기름오염 사고가 발생하면 여러 가지 방제 방법 중 물리적 회수 방법을 우선적으로 사용하고 유처리제는 최후 수단으로 고려하는 경향이 있다. 유처리제는 수중으로 기름이 신속히 분산되도록 하여 해수면으로부터 제거하는 방법이다. 해수면으로부터 신속히 기름을 제거하는데 대한 유처리제의 효용성은 널리 증명되어 왔으나 아직도 대부분의 국가들은 해양환경에 미치는 독성을 우려하여 적극적인 사용을 하지 않고 있는 실정이다. 보고된 자료에 의하면 유처리제 사용 후 수중생물에 대한 독성은 발견되지 않았으며, 유처리제와 혼합된 기름이 기 름 그 자체보다 독성이 더 크게 나타나지 않았다. 멕시코만 기름유출 사고 시 미국 정부와 BP사는 최대한 해안에 기름이 도달하지 않는데 중 점을 두고 해수면뿐만 아니라 수중의 기름에 대해서도 유처리제를 사용하였다.
        3,000원
        13.
        1985.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A generalization of the original ¨ O p i k ′ s cellular convection theory has been made to accomodate a rotating convective medium. With the use of the formulation, a set of rotating model envelopes of the sun and late type main sequence stars have been constructed under three different rotation periods. Their thermal structures are presented and characteristics of their convection are discussed in the context of stellar dynamo. In the present study it is noted that the rotational angular velocity increases in wards with depth, and its increase turns out to be about 6% at the bottom of the solar convection zone.
        4,600원
        14.
        2022.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The Ionospheric Anomaly Monitoring by Magnetometer And Plasma-probe (IAMMAP) is one of the scientific instruments for the Compact Advanced Satellite 500-3 (CAS 500-3) which is planned to be launched by Korean Space Launch Vehicle in 2024. The main scientific objective of IAMMAP is to understand the complicated correlation between the equatorial electro-jet (EEJ) and the equatorial ionization anomaly (EIA) which play important roles in the dynamics of the ionospheric plasma in the dayside equator region. IAMMAP consists of an impedance probe (IP) for precise plasma measurement and magnetometers for EEJ current estimation. The designated sun-synchronous orbit along the quasi-meridional plane makes the instrument suitable for studying the EIA and EEJ. The newly-devised IP is expected to obtain the electron density of the ionosphere with unprecedented precision by measuring the upper-hybrid frequency (fUHR) of the ionospheric plasma, which is not affected by the satellite geometry, the spacecraft potential, or contamination unlike conventional Langmuir probes. A set of temperaturetolerant precision fluxgate magnetometers, called Adaptive In-phase MAGnetometer, is employed also for studying the complicated current system in the ionosphere and magnetosphere, which is particularly related with the EEJ caused by the potential difference along the zonal direction.
        15.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        Chronological aging and photoaging affect appearance, causing wrinkles, pigmentation, texture changes, and loss of elasticity in the skin. Phragmites communis is a tall perennial herb used for its high nutritional value and for medicinal purposes, such as relief from fever and vomiting and facilitation of diuresis. In this study, we investigated the effects of ethanol extract of P. communis rhizome (PCE) on skin aging. The total flavonoid and total phenolic content in PCE were 2.92 ± 0.007 ㎍ of quercetin equivalents (QE) and 231.8 ± 0.001 ㎍ of gallic acid equivalents (GAE) per 100 ㎎ of dried extract (n = 3). The half-maximal inhibitory concentration (IC50) values of PCE for 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and hydrogen peroxide scavenging activities were 0.96 and 0.97 ㎎/mL, respectively. PCE showed inhibitory effects on tyrosinase when L-tyrosine (IC50 = 1.25 ㎎/mL) and L-3,4-dihydroxyphenylalanine (IC50 = 0.92 ㎎/mL) were used as substrates. PCE treatment up to 200 ㎍/mL for 24 h did not cause any significant cytotoxicity in B16F10 melanocytes, human dermal fibroblasts (HDFs), and HaCaT keratinocytes. In B16F10 melanocytes, PCE (25 and 50 ㎍ /mL) inhibited melanin production and cellular tyrosinase activity after challenge with α-melanocyte-stimulating hormone (α-MSH; p < 0.05). In HDFs, PCE suppressed the mRNA expression of matrix metalloproteinase-1 (MMP-1) and reduced the activity of elastase (p < 0.05). In addition, ultraviolet B (UVB)-mediated downregulation of hyaluronic acid synthase-2 gene expression in HaCaT keratinocytes was also effectively suppressed by PCE treatment. Overall, our results showed that PCE has potential anti-skin aging activity associated with the suppression of hyperpigmentation, wrinkle formation, and reduction in dryness. PCE is a promising candidate for the development of an anti-skin aging cosmetic ingredient.
        16.
        2020.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Particle-in-cell simulations were performed to understand the interaction of the solar wind with localized magnetic fields on the sunlit surface of the Moon. The results indicated a mini-magnetosphere was formed which had a thin magnetopause with the thickness of the electron skin depth. It was also found that the solar wind penetrated into the cavity of the magnetosphere intermittently rather than in a steady manner. The solar wind that moved around the magnetosphere was observed to hit the surface of the Moon, implying that it may be the cause of the lunar swirl formation on the surface.
        17.
        2017.05 서비스 종료(열람 제한)
        Background : This study aimed to investigate the effect of elevated temperature by climate change on growth and ginsenoside contents of Korean ginseng, which requires low temperature during growth period. Methods and Results : Yunpoong was transplanted in temperature gradient chamber (TGC) for high temperature treatment and then growth characteristics and ginsenoside contents were investigated by growth period. Stem length, petiole length, leaf length and leaf width were increased as the temperature was higher than Ambient Temperature (Amb), but stalk diameter was decreased and small petiole length, number of petiole and leaf were no significant difference. Root growth, whereas, including length diameter and weight were decreased as the temperature was higher than Amb. Compared with Amb, root length, diameter and weight were decreased by 19.6%, 22.4% and 41.5% at Amb+6, respectively. The higher the temperatures are associated with the more ginsenoside contents. Compared to Amb, total ginsenoside contents were increased by 68% and 78% at Amb+4℃ and Amb+6℃, respectively. Almost all contents of individual ginsenoside, with the exception of Rg1, made a significant difference. Conclusion : When temperatures rises during growth period, the growth of ginseng was decreased but, ginsenoside contents were increased.
        18.
        2017.05 서비스 종료(열람 제한)
        Background : The purpose of this study is to investigate the effect of split application and adapted fertilization application cultivation in stable medicinal herbs production of Angelica acutiloba K. And it accomplished one’s purpose to GAP guide manual established standard method of cultivation technology, contribute to the enlargement of farm’s income. Methods and Results : Method of fertilization application were conducted under four condition compose to standard application (N-P-K-Compost: fermented mixed oil cake fertilizer applied at 14-10-10-600 ㎏․10 a−1cultivation. Compost and fused phosphate applied at 100% of basal fertilizer in April 14. The split application level of standard application (N-K) applied at 100%, 50%, 40%, 30% of basal fertilizer in April 14, 50%, 40% and 30% of top dressing were two, three times application (N-K) in June 1, July 15, August 15, 25% and 20% respectively. Sowing dates with Jangsung varieties in April 28 of the year 2015. Planting density were spaced 30 ㎝ apart in rows 15 ㎝ apart with black color non-woven cloth covering open cultivation by level row 90 ㎝. Plot design randomized block 3 repetition. Conclusion : Growth characteristics by 50%, 70% and 60% of top dressing were two, three times application (N-K) in June 1, July 15, August 15 compared to standard application (N-K) applied at 100% basal fertilizer, aerial part as a result were so many such amount of growth as number of leaf per plant, etc., Length of leaf and main root of aboveground, subterranean part growth increment rising highest. Dried roots yields compared to standard fertilizer 100%application (217 kg․10 a−1) treatment. 50%, 70% and 60% of top dressing were two, three times application (N-K) increased by 6%, 14%, and 18%. respectively.
        19.
        2017.05 서비스 종료(열람 제한)
        Background : The purpose of this study was to evaluate methods to high quality medicinal vegetables, thereby increasing farm income. This study investigated the effects of different green manures crop and application culture stable foliage production in Peucedanum japonicum Thunberg. Methods and Results : Method of application with green manure crop were conducted under four condition compose to control (non application), single cropping in barley, hairy vetch and mixed cropping in hairy vetch (60%) + barley (40%)culture. Sowing dates of green manure crop were October 14 in 2014. Transplanting with Jeonam Yeosu varieties in Junel 28 by growing pot seedling for 45 days in 2015. Method of application were standard application (N-P-K-Compost applied at 20-12-10-600 ㎏․10 a−1). Plants were spaced 10 ㎝ apart in rows 10 ㎝ apart with open cultivation. Conclusions : The utilization effect of nitrogen supplied by green manure crop was highest with the hairy vetch by 21.1% in single cropping and hairy vetch + barley by 29.8% in mixed cropping. Organic matter, available phosphate, K2O, CaO, and MgO of soil increased in plots with the mixed cropping hairy vetch + barley culture. Non application < barley < hairy vetch < hairy vetch + barley in mixed cropping, aerial part as a result were so many such amount of growth as number of leaf per plant, etc., green leaf yields is untreated control plot (1,876 kg․10 a−1) compared to 7% from using barley culture, hairy vetch culture 10% higher and hairy vetch + barley culture increased to 15% of the most.
        20.
        2016.10 서비스 종료(열람 제한)
        Background : Ginseng (Panax ginseng C. A. Meyer) is a precious herb plant belonging to Araliaceae family especially in Asia and it has been cultivated more than a thousand years as a traditional medicine. Due to their pharmacological efficacy, old ginseng plants are traded high price, however, there are no crucial criteria to determine the ginseng age. To prevent illegal transactions, we assessed the telomere of ginseng roots based on modifications of the assays reported previously. Methods and Results : It is known that telomere length of ginseng root is shorter upon organismal aging. In this study, to support the determination of ginseng age, we modified and investigated methods through telomere analysis. Firstly, we examined the southern blot analysis whether telomere length depends on ginseng age. Based on previous study, we measured telomerase activity that is correlate with age. Furthermore, telomeric DNA was quantified by fluorescence in situ hybridization (FISH) to corroborate telomere shortening. The older ginseng root was shown short telomere length to compare with younger ginseng roots. Also enzyme activity of telomerase and amount of telomeric DNA represented decrease patterns upon age. Conclusion : Taken together, it is help to determine the age of ginseng through various methods using telomere because the results shown to positive correlation between telomeric characteristics and age for ginseng.
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