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        검색결과 29

        1.
        2023.11 구독 인증기관·개인회원 무료
        The domestic Pressurized Heavy Water Reactor (PWHR) nuclear power plant, Wolsong Unit 1, was permanently shut down on December 24, 2019. However, research on decommissioning has mainly focused on Pressurized Water Reactors (PWRs), with a notable absence of both domestic and international experience in the decommissioning of PHWRs. If proper business management such as radiation safety and waste is not performed, it can lead to increased business risks and costs in decommissioning. Therefore, the assessment of waste volume and cost, which provide fundamental data for the nuclear decommissioning process, is a crucial technical requirement before initiating the actual decommissioning of Wolsong Unit 1. Decommissioning radiation-contaminated structures and facilities presents significant challenges due to high radiation levels, making it difficult for workers to access these areas. Therefore, technology development should precede decommissioning process assessments and safety evaluations, facilitating the derivation of optimal decommissioning procedures and ensuring worker safety while enhancing the efficiency of decommissioning operations. In this study, we have developed a program to estimate decommissioning waste amounts for PHWRs, building upon prior research on PWR decommissioning projects while accounting for the specific design characteristics of PHWRs. To evaluate the amount of radioactive waste generated during decommissioning, we considered the characteristics of radioactive waste, disposal methods, packaging container specifications, and the criteria for the transfer of radioactive waste to disposal operators. Based on the derived algorithm, we conducted a detailed design and implemented the program. The proposed program is based on 3D modeling of the decommissioning components and the calculation of the Work Difficulty Factor (WDF), which is used to determine the time weighting factors for each task. Program users can select the cutting and packaging conditions for decommissioning components, estimate waste amount based on the chosen decommissioning method, and calculate costs using time weighting factors. It can be applied not only to PHWRs, but also to PWRs and non-nuclear fields, providing a flexible tool for optimizing decommissioning process.
        2.
        2022.10 구독 인증기관·개인회원 무료
        With the aging of nuclear power plants (NPPs) in 37 countries around the world, 207 out of 437 NPPs have been permanently shutdown as of August 2022 according to the IAEA. In Korea, the decommissioning of NPPs is emerging as a challenge due to the permanent shutdown of Kori Unit 1 and Wolsong Unit 1. However, there are no cases of decommissioning activities for Heavy Water Reactor (HWR) such as Wolsong Unit 1 although most of the decommissioning technologies for Light Water Reactor (LWR) such as Kori Unit 1 have been developed and there are cases of overseas decommissioning activities. This study shows the development of a decommissioning waste amount/cost/process linkage program for decommissioning Pressurized Heavy Water Reactor (PHWR), i.e. CANDU NPPs. The proposed program is an integrated management program that can derive optimal processes from an economic and safety perspective when decommissioning PHWR based on 3D modeling of the structures and digital mock-up system that links the characteristic data of PHWR, equipment and construction methods. This program can be used to simulate the nuclear decommissioning activities in a virtual space in three dimensions, and to evaluate the decommissioning operation characteristics, waste amount, cost, and exposure dose to worker. In order to verify the results, our methods for calculating optimal decommissioning quantity, which are closely related to radiological impact on workers and cost reduction during decommissioning, were compared with the methods of the foreign specialized institution (NAGRA). The optimal decommissioning quantity can be calculated by classifying the radioactivity level through MCNP modeling of waste, investigating domestic disposal containers, and selecting cutting sizes, so that costs can be reduced according to the final disposal waste reduction. As the target waste to be decommissioning for comparative study with NAGRA, the calandria in PHWR was modeled using MCNP. For packaging waste container, NAGRA selected three (P2A, P3, MOSAIK), and we selected two (P2A, P3) and compared them. It is intended to develop an integrated management program to derive the optimal process for decommissioning PHWR by linking the optimal decommissioning quantity calculation methodology with the detailed studies on exposure dose to worker, decommissioning order, difficulty of work, and cost evaluation. As a result, it is considered that it can be used not only for PHWR but also for other types of NPPs decommissioning in the future to derive optimal results such as worker safety and cost reduction.
        3.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Streptococcus mutans and Streptococcus sobrinus play important roles in dental caries. Coptis chinensis is a natural product with antimicrobial activity against enterobacteria; however, its effects on oral streptococci are still unknown. Therefore, the effects of C. chinensis on the growth and biofilm formation of the representative cariogenic bacteria S. mutans and S. sobrinus were investigated for the possible use of C. chinensis as an anticaries agent. The C. chinensis extract was diluted with sterile distilled water, and 0.1–2.5% of the extract was used in the experiment. The effects of the C. chinensis extract on the growth and glucan formation of S. mutans and S. sobrinus were measured by viable cell counting and spectrophotometry at 650 nm absorbance, respectively. Crystal violet staining was also carried out to confirm the C. chinensis extract’s inhibitory effect on biofilm formation. The C. chinensis extract significantly inhibited the growth of S. mutans and S. sobrinus at concentrations of ≥ 0.3% as compared with the control group. The viable cell count of colonies decreased by 1.7-fold and 1.2-fold at 2.5% and 1.25%, respectively, compared with the control group. The biofilm formation of S. mutans and S. sobrinus was inhibited by > 20-fold at C. chinensis extract concentrations of ≥ 1.25% as compared with the control group. In summary, the C. chinensis extract inhibited the growth and biofilm and glucan formation of S. mutans and S. sobrinus . Therefore, C. chinensis might be a potential candidate for controlling dental caries.
        4,000원
        4.
        2018.07 구독 인증기관·개인회원 무료
        This research explored antecedents of stickiness of m-commerce sites, based on the push–pull–mooring (PPM) framework, which was developed to explain what leads people to move from one original location to another. In the current study, the stickiness of m-commerce sites was used as the opposite concept to switching. Therefore, pull effects refer to the positive factors which make consumers stick to an m-commerce site, while push effects refer to the negative factors which make consumers not stick with an m-commerce site. After reviewing the literature, responsiveness, ubiquity, enjoyment, and effectiveness were selected as the pull effects, while privacy concern and efficiency were selected as the push effects. The amount of money spent in specific mobile sites was considered as a mooring effect. According to the results of the structural equation modeling analysis, efficiency actually had a negative impact on stickiness of m-commerce sites. Also, a test of the mooring effect suggested that the negative impact of efficiency on stickiness of m-commerce sites was greater for people who spent more money in their mobile shopping compared to those who spent less. For both the high and low spending groups, responsiveness was the important pull effect as it was the strongest predictor of enjoyment for the low spending group and the strongest predictor of effectiveness for the high spending group (note that enjoyment and effectiveness had the strongest positive impacts on stickiness of m-commerce sites for the low and high spending groups, respectively.). Therefore, the fast response and feedback on m-commerce sites should increase consumers’ stickiness to these sites regardless of the amount consumers spend on these sites. On the other hand, the duration and retention of the low spending group of consumers were influenced by enjoyment the most.
        5.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the effects of foot position adjuster on body alignment and weight loads in chronic stroke patients. The subjects were 15 chronic stroke patients who were admitted to KHospital in Daegu, South Korea. The study compared the body alignment and weight load changes on flat ground with the foot position adjuster using Foot scan and Dartfish video analysis software. In the results of this study, posterior superior iliac spine (PSIS) alignment decreased significantly after use of the foot position adjuster and center pressure was significantly increased after use of the foot position adjuster. This study suggests that foot position adjuster influences body alignment and weight distribution.
        4,000원
        6.
        2016.04 구독 인증기관·개인회원 무료
        Various insect pests and plant disease can outbreak in a field. For the effective control of pests and plant diseases during crop cultivation, farmers simultaneously or sequentially spray various eco-friendly agricultural materials (EFAM), chemical pesticides and microbial control agents on the same fields. It was reported that many agrochemicals are harmful to entomopathogenic fungi, especially some fungicides with broad spectrum activity that are routinely applied for the control of plant diseases. In addition, some pesticides may antagonize the potential insecticidal activity and efficiency of entomopathogenic fungi. Therefore, sometimes the utilization of fungal entomopathogen in forestry and agricultural production is limited because of the undesirable interference from some fungicides and pesticides. There is little research that examines the compatibility of these EFAMs with entomopathogenic fungi and the influence of EFAMs on the control efficacy of mycopesticides. We conducted a study of influence of pretreated eco-friendly agricultural materials on control efficacy of Isaria javanica isolate against sweet potato whitefly.
        7.
        2016.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungus is a useful control agent to sucking type insect such as whitefly and aphid. The fungi are influenced by some environmental factors such as relative humidity, temperature and UV and cause slow and fluctuation in pest control efficacy. Especially, UV kills conidia or spores of entomopathogenic fungi and a mycopesticide using fungi has short control period in field. UV intensity changes from season to season. Survival rate of entomopathognic fungi treated may differ from seasons and will show different control efficacy. Therefore, we conducted a study to estimate the persistence of an Isaria javanica isolate, which was already reported as sweet potato whitefly control agent, in potted greenhouse soil planted different crops. The number of survival spore decreased gradually and differ from seasons.
        8.
        2016.04 구독 인증기관·개인회원 무료
        As ubiquitous organisms entomopathogenic fungi may natually occur within environment including phylloplanes and soil or deposite and survive for a while after spraying a fungal suspension to control insect pest. The existence of pathogenic fungi is a threat to arthropods foraging for food and oviposition sites. The detection and avoidance of pathogens is important for host survival, longevity and ultimate fitness. Although entomopathogenic fungi are ubiquitous worldwide and act as common natural enemies of many invertebrate species, very few studies have conducted abiut the detection and avoidance of pathogenic fungi by insect pest. We have studied that an insect pest can recognize a high virulence fungi on crop surface, avoid oviposition and don’t enter the field treated their pathogen.
        9.
        2016.04 구독 인증기관·개인회원 무료
        Entomopathogenic fungi are natural enemies of insect pests and contribute to the natural regulation of their host populations. These fungal group are often used as active ingredients for microbial insect pest control. In addition, the potential antimicrobial effect by entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have recently been reported against fungal plant pathogens. Dual microbial control effects with entomopathogenic fungi against both aphids and cucumber powdery mildew had reported in Canada. In our previous studies we conducted bioassay with entomopathogenic fungi to develop dual microbial control agent which can control both aphid and fungal plant disease. We selected an Beauveria bassiana isolate which has high dual control effects against both cotton aphid, Aphis gossypii and sclerotinia rot, Sclerotinia sclerotiorum. In this study, we have tested the dual control efficacy of the B. bassiana isolate against cotton aphid and sclerotinia rot on whole potted cucumber plants. We found that the B. bassiana isolate protected the plant from cotton aphid and sclerotinia rot under laboratory condition.
        10.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ampelopsis brevipedunculata, a porcelain berry that is a kind of Korean domestic wild berry (Viticeae), has been known to be resistant to diseases and insects. A total of 2,622 unigenes containing 912 contigs and 1,710 singletons were obtained by sequencing 5,839 expressed sequence tag (EST) clones derived from the cDNA library of wild grape, A. brevipedunculata. In the gene ontology analysis, 1,175 genes related to biological process, 1,516 genes related to molecular function, and 1,413 ones related to cell components were annotated. Among the genes showing molecular function, 17 clones were classified into defense-related genes, and 102 were known to be related with responses to stress in plants. Domains, such as leucine-rich repeat, Serine/threonine protein kinase-related, WD40 repeat, EF-hand calcium-binding, pentatricopeptide repeat, and pathogenesis-related transcriptional factor were highly expressed. Genes encoding defense related proteins, such as chitinase, catalase, protein-serine/threonine kinases, were also clustered into an abundant group in cDNAs from A. brevipedunculata. Approximately, 80 simple sequence repeats with 2~5 nucleotides were detected in the cDNAs of A. brevipedunculata. These data could provide useful information for the genetic analysis of wild grapevines and in programs for breeding grape cultivars.
        4,500원
        11.
        2010.06 구독 인증기관 무료, 개인회원 유료
        Chronic inflammatory diseases such as Crohn′s disease and ulcerative colitis are associated with increased risk of colon adenocarcinoma. Apoptic induction of colon cancer cells by cytokines and death receptors is an important anti-cancer therapy. We observed that co-administration of TNFα and IFNγ in human colon cancer cell line, HCT116, resulted in cell death and expression of IL-32. Cleavage forms of caspase-3, caspase-9, and PARP were increased in TNFα / IFNγ-treated HCT116. mRNA expression of death receptors, including TNFR1 and Fas were not changed and NO generation was not induced by combination of TNFα and IFNγ. However, mRNA expression of IL-32α, β, and γ was increased in TNFα / IFNγ-treated HCT116. To determine the effect of IL-32 in HCT116 cell apoptosis by TNFα / IFNγ stimulation, IL-32 siRNA-transfected HCT116 cells were cultured with TNFα / IFNγ and cell proliferation was measured. IL-32 siRNA induced slight recovery of cell viability of TNFα / IFNγ-stimulated HCT116. These results suggest that IL-32 is not directly related to apoptosis of HCT116 by TNFα / IFNγ stimulation. However, IL-32 expression by TNFα or TNFα / IFNγ in a colon cancer cell line is very interesting because of the unknown effect of IL-32 in colon cancer. Our study will contribute to development of studies for IL-32 function in human colon cancer and anti-cancer therapies using cytokines.
        4,000원
        14.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        For rapid production of freesia ‘Shiny Gold’ shoots by using a bioreactor, several culture conditions were investigated. Young shoots (< 1 ㎝) obtained from freesia corm section in vitro were used as plant materials for this experiment. As a basic experimental environment, 20 young shoots were inoculated into a 5 L balloon type bubble reactor which contained 1 L 1/2 strength MS medium supplemented with 30 g sucrose (3%), and the aeration was 0.1 vvm (vessel volumes per minute). The bioreactors were placed in a growth room with 23℃ temperature, 60% relative humidity and 60 μmol·m-2·s-1 light condition (16 h/8 h, day/night). The concentrations of MS media were set with 1/4, 1/2, 1 strength, medium volume 10, 20, 40%, sucrose concentration 3, 6, 9%, and aeration 0.1, 0.2, 0.4 vvm. After 4 weeks of cultivation, the growth indexes including the fresh and dry weight, and plant height were evaluated. At the same time, the consumption, pH, and EC of medium were estimated 4 weeks after incubating. The best results were achieved when 40 young shoots were incubated in a bioreactor in which 1 L of 1/2 strength MS medium supplemented with 6% sucrose was used for the rapid production of freesia shoots. The shoots were 17 cm in plant height and 1.0 g in fresh weight only 4 weeks after incubation which could be a good plant material suitable for corm enlargement i
        15.
        2016.10 서비스 종료(열람 제한)
        Background : This experiment was carried out to improve the labor-intensive task to construct of the traditional ginseng shading system in Korea. In this experiment the selected shading materials was new 6 kinds that HDPE - knitted- monofilament and taped PE Net, with taking into account of the amount of light and the amount of leakage to screen the UV stabilized 0.3% - 0.6%. Compared with the traditional shading material, the black-shading material (wt. 200g/㎡) and the yellow shading material (wt. 300g/㎡) was suitable for the ginseng growing environments in Korea. Methods and Results : The installation of shading system was the 45 degree slope -2 meter height from the ground with the selected shading materials for the wide structure ginseng cultivation. Temperature and light intensity was measured with a week interval from the surface to a height of 30cm. The two kinds of the 1st selected materials and the traditional black + blue two layer shading materials, aluminum screen, Canada Gintec shading material, total 5 kinds of materials were installed in wide structure. The growing environmental analysis was measured using data logs (watchdog 1600series). Conclusion : In the first selection of shading materials for Ginseng wide structure, the levels of light intensity were higher in order of blue-shading> Aluminum- shading> black-shading order. The temperatures of the under wide structures were lower in order of the black-shading< aluminum-shading screen< blue-shading order, especially the temperature of the black shading material was lower than the outside temperature. For the second selection of shading material of the ginseng wide structure, the black and yellow shading material were superior to the other materials, in the amount of light shading material and growing conditions and the degree of leakage etc. The temperatures of mid-May in wide structures of ginseng cultivation were higher in order of aluminum-screen> Canada shading materials (Gintec Co.) 2 layer material> Yellow shading> black shading order, and also the amounts of light intensity also was shown to be with the same manner
        16.
        2016.05 서비스 종료(열람 제한)
        Background : The Ginseng has been one of the crops that represents Korea, and the main export items in the 1960s, Now it occupies the first exports of agricultural products. The Eco-friendly cultivation of Ginseng was difficult for various reasons. But the cultivation in Green House can be suppressed disease occurrence, when utilizing an environmentally friendly materials has the advantage that can dramatically increase the income by possible organic production. For other crops, it made up a lot of studies on water management, But the studies on water management of ginseng is somewhat lacking. Therefore, this study was conducted to establish appropriate soil- moisture-management-systems within the house of ginseng cultivation. Methods and Results : The type of house is a double steel structure. The first layer was PE film, the second layer was the blue shading net and 75% black shading net. The Soil texture was silt loam and the Soil Series was YEONGOK Series. Install the house on the adjacent paddy soil and upland soil, and planting on April 30, 2011 which was cultivated by the straw mulching. The irrigation start point was the 40, 30, 20kpa, and the end point was treated with 15, 10kpa. Soil moisture measurements were determined by tension meter(Jet Fill) depth 20cm in soil. Growth and Yield Survey was conducted in accordance with the Rural Development Administration (RDA) standard research. Statistical analysis of the results were analyzed using the Microsoft's Excel 2003. Conclusion : In a survey due to differences in soil traits and Irrigation point, from 2 years to 4years of root weight and yield of Ginseng were heavier in the upland, especially 30kpa irrigation point treatment was heaviest than the other treatments. From 5year to 6 Years of ginseng has showed heavier in paddy soil, the most treatment was 30kpa- 15kpa irrigation point. This trend was the same in upland soil. Soil moisture management in the case of silt loam, the humid-state-control was more advantageous than dry-state control in upland and paddy soil.
        18.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        ‘Seohong’ was bred within the potato breeding program of National Institute of Highland Agriculture (NIHA). It was originated from a cross made in 1997 between ‘Jashim’ as a female and 93K65-1 as a male parent. Seohong was evaluated as a seedling number 97S05-1 for tuber characteristics, growth and yielding ability from 2001 to 2002, and than this clone was renamed as Daegwan 1-82. This clone was evaluated in the regional yield trial and the disease resistance in the five locations for three years. Finally, this clone was named as ‘Seohong’ and registered a new recommended potato cultivar in 2006. This cultivar has a round, shallow eye depth, light red-skinned tuber characteristics and low to medium dry matter content. It showed high resistance to common scab (Streptomyces scabies) and potato leaf roll virus (PLRV), however it was susceptible to potato virus Y (PVY) and late blight (Phytophthora infestans). Its mean tuber yields from the regional yield trial and winter cropping trial were 12 and 49 percent higher than that of ‘Superior’, respectively.
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