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        검색결과 15

        1.
        2023.11 구독 인증기관·개인회원 무료
        It has been investigated on the management of Strontium-90 in KAERI. It is needed to separate the solute from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt in our previous study. Strontium chloride was successfully carbonated by reactive distillation of SrCl2 – K2CO3 – LiCl – KCl system. In this study, it was tried to develop another route to recover strontium from the salt solution by a solid-solid reaction for avoiding the entrainment of product and the salt-K2CO3 reaction. Reactive distillation experiments were carried out for SrCl2 - K2CO3 – LiCl – KCl system. The carbonation temperature and pressure were 520°C and 0.8 bar. After the carbonation reaction, the temperature was elevated to 820°C to remove KCl from the reaction product. SrCO3 and KCl peaks were found in the XRD analysis of the residual product. It could be concluded that SrCl2 can be successfully carbonated after salt removal by the solid-solid reaction.
        2.
        2023.05 구독 인증기관·개인회원 무료
        It has been investigated on the management of the nuclides in KAERI. Strontium-90 is a high heatgenerating nuclide in spent nuclear fuel. It is needed to separate the salt from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt. It was investigated on operating conditions of reactive distillation process for the recovery of the strontium from the salt solution. At a reduced pressure, considerable amount of the carbonation agents such as K2CO3 and Li2CO3 were reduced during heating in the distiller due to the thermal decomposition. Therefore, the two step process was proposed, which is composed of a reaction step at an atmospheric pressure and a salt distillation step at a reduced pressure. In the reaction step, the condition of low temperature and high pressure is suitable to suppress the decomposition of the carbonation agent. In the salt distillation step, reduced pressure is preferable at a suitable temperature depending on the evaporation rate of the salt.
        3.
        2022.10 구독 인증기관·개인회원 무료
        It has been studied on the disposal area reduction for the used nuclear fuel by the management of high decay-heat nuclides, long-lived nuclides, and highly mobile nuclides. It was investigated on the management of the nuclides in KAERI. Strontium-90 is a high heat-generating nuclide in spent nuclear fuel. It is needed to separate the salt from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. Vacuum distillation was used for the separation of strontium from the molten salt. Potassium carbonate was chosen as a reactive distillation reagent for SrCl2 – LiCl – KCl system by the thermodynamic calculation. Reactive distillation experiments were carried out. The residual was mainly SrCO3 in the XRD analysis. It could be concluded that K2CO3 could be one of the suitable reagents for the reactive distillation. The salt in the long–lived nuclide powders should be removed to prepare the block for disposal. Experiments were carried out using W powders (surrogate) and U3O8 powders to develop a process for the removal of the residual salt from UOx powders. The salts were successfully removed from the W and U3O8 powders by distillation.
        4.
        2022.05 구독 인증기관·개인회원 무료
        Strontium-90 is a high heat-generating nuclide in spent nuclear fuel. The removal of the nuclide separation is indispensable to reduce the burden of storage and disposal of high-level radioactive waste. Korea Atomic Energy Research Institute has developed the molten salt immersion technique to separate the strontium by the chlorination of the strontium oxide in molten salt. It is needed to separate the salt for the recovery of strontium from the salt solution after the chlorination reaction. In this study, it was investigated on the recovery of the strontium from the salt. Vacuum distillation was used for the separation of strontium from the molten salt. The vapor pressures of the candidate salts were calculated by HSC chemistry and the apparent evaporation rates (AER) were measured at 830°C to evaluate the salts for strontium recovery. The candidate salts were LiCl, KCl, MgCl2, NaCl and CaCl2. The AERs of MgCl2 and NaCl were 1.9 and 1.3 g/cm2-h, respectively. Those two salts can be separated from the strontium compound even though the AER values are much lower than those of LiCl-KCl (~ 8 g/cm2-h). CaCl2 salt was rarely evaporated (AER < 0.03 g/cm2-h) and it is not suitable to use as a strontium recovery salt. Therefore, MgCl2, NaCl, LiCl and KCl can be regarded as candidates for a strontium recovery salt.
        7.
        2017.04 구독 인증기관·개인회원 무료
        Insect infestation leads to huge loss of agricultural products and transmission of vector-borne diseases causing millions of deaths per annum. Juvenile hormone (JH) controls the development and reproduction of insects, therefore the grouth of insects can be inhibited by interfering the action of JH. Based on this, we developed a novel insect species-specific screening system to identify juvenile hormone antagonists (JHANs) from natural origin. These compounds can disrupt JH-mediated insect development by interfering the binding of a heterodimer, steroid receptor coactivator (SRC), with its partner protein, the methoprene-tolerant (Met) JH receptor. This screening system could be used as a new tool to develop eco-friendly and species-specific insecticides.
        8.
        2013.04 구독 인증기관·개인회원 무료
        Melanization is a unique defence mechanism in arthropods involved in wound healing and pathogen encapsulation. Phenoloxidases (PPOs) are key enzymes of melanization, which mediate the enzymatic conversion of tyrosine to eumelanin. A serine-protease (SP) cascade, similar to the blood-clotting cascade of vertebrates, proteolytically activates prophenoloxidases to phenoloxidases. This proteolytic activation is tightly controlled by serpins and other melanization inhibitors. Melanization has been regarded as one of key immune responses against malaria parasites in mosquitoes. The ookinete melanization of both the simian malaria parasite, Plasmodium cynomolgi, and of the rodent parasite, Plasmodium berghei, prevent parasite development in the human malaria vector, An, gambiae. However, the recent studies revealed a melanization response regulated by Serpin-2 and two C-type lectins (CTL4 and CTLMA-2) was shown to result in ookinete melanization but did not affect the development of the natural human parasite P. falciparum in the mosquito. Instead of melanization, TEP1/APL1/LRIM1 complement-like pathway has been identified as major immune response that regulate parasite loads in the natural association of An. gambiae and P. falciparum. The studies by me and my colleagues revealed another melanization response independent on Serpin-2. Genome analyses of mosquitoes revealed a large expansion of the PPO, SP, and serpin genes potentially involved in the melanization pathway. This expansion was devoted to existence of at least two distinct SP-Serpin regulation modules in controlling separate melanization responses, tissue and hemolymph melanization, in the mosquito, Aedes aegypti. Tissue melanization regulated by Serpin-2 has role in melanotic tumor formation, but not in ookinete melanization. Hemolymph melanization regulated by Serpin-1 and a couple of SPs was activated by the infection of various pathogens and is involved in anti-malarial defense against the avian malaria parasite, P. gallinaceum. A new type of regulator, CLSP2, negatively modulate this hemolymph melanization. Cross-talk between hemolymph melanization and complement-like pathway will be discussed.
        9.
        2011.05 구독 인증기관·개인회원 무료
        The Black pine bast scale, Matsucoccus thunbergianae is one of the most serious in black pine, Pinus thunbergii forests in Korea. Since this pest was first reported in Goheung, Korea in 1963, which is gradually spread into neighboring regions and now occurs in many regions of the southern and eastern part of the Korean peninsula. The monitoring for distribution of M. thunbergianae was able to observed by naked eye egg sacs and pupa of male on the host until now. Therefore, this monitoring was very difficult in the low density of M. thubergianae. This experiment was conducted to use simple and practical moving cross-shaped flat trap for monitoring of M. thunbergianae. The monitoring of M. thunbergianae using the device was carried out to southern regions of the Korean peninsula. The first emergence of male showed mid. March in Namhae and late march in Busan, Jinju and Pohang. The peak of emergence showed late March in Namhae and early April in the other regions. When the number of M. thunbergianae intermediate nymph showed 58~59, 11~44 and 8~25 on 39.25 ㎠ bark area of the black pine, Pinus thubergii for 1 week, the number of captured its male adult was 58~83, 67~488 and 1~55 on the moving cross-shaped flat trap (10× 13㎝), respectively. The low density of M. thunbergianae was some few the number of capture, but there were no significant difference in its high density. Also, the number of captured its male adult was no significant in the different color (yellow, red, white and blue) of the moving cross-shaped flat trap.
        10.
        2009.10 구독 인증기관·개인회원 무료
        The most effective methods against pine wilt disease (Bursaphelenchus xylophilus, PWD), black pine bast scale (Matsucoccus thunbergianae), pine needle gall midge (Thecodiplosis japonensis) is the trunk injection of insecticides. The period of trunk injection that was considered with ecology and physiology of pests such as pine wilt disease, black pine bast scale and pine needle gall midge, was applied from Dec. to next Feb. and June, Dec. respectively. And there are differences in quantities of being injected chemicals to pine trees by the period of trunk injection. Thus, we investigated to prevent the effect of insecticides, to estimate the effect under the trunk injection of insecticides for pine trees against pests by the injecting period and time, boring site, opening and shutting of injection site. On Pinuns thunbergii, it was examined to figure out the effect of insecticides by the injecting period, twice a month on a sunny day around 10 AM from January to September. Injecting of insecticides was tested at a dose of 5ml per cm dbh of a pine tree after boring with hand drill at 50 cm high from the ground. As a result, abmectin 1.8% EC and phospamidon 50% SL were injected over 90% of mortalities from the end of January to the middle of March but as time goes by, injecting insecticides tended to decrease. To compare the volume of injecting insecticides in a day, between 10 AM and 2 PM on February 23rd, abamectin 1.8% EC was injected at a dose of 5ml per pine trees with micro pipette after boring with a drill machine at 50 cm high from the ground. As a result, injecting insecticide of a pine which was injected around 10 AM was completely injected and about 90% of the insecticide was injected in case of a pine that was injected around 2 PM. Trunk injection of insecticides was examined to figure out differences of the volume of injected insecticides before and after rain. There was no difference not only the rainfall but also the bored direction.
        11.
        2009.10 구독 인증기관·개인회원 무료
        Trunk injection of nematicides is applied to prevent pine wilt disease(PWD). Although the trunk injection of nematicides is effective to PWD prevention, it is not effective to vector insects such as adults of M. alternatus and M. saltuarius. Thus, This study was investigated for the insecticidal activity and the effect of feeding deterrence by injecting to pine trees with acetamiprid. For screening effective nematicides, some insecticides were injected to pines on December 30th, 2008 and their insecticidal activities and feeding areas of M. alternatus and M. saltuarius were investigated in the insects breeding dishes (100× 40mm) where put on 1 to 2-year-old twig which was selected from injected pine trees in early June. As a result, insecticidal activity and feeding deterrence of acetamicprid were most effective. Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, were 170.3±107.0 mm2 and 258.0±123.2 mm2 respectively. And Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of pines injected at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid, were 57.7±72.3 mm2 and 65.7±51.2 mm2 respectively and their mortalities also were 0%, 28.6%. The feeding areas of M. alterantus adults tested with 1-year-old twig and 2-year-old twig of pine trees injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it and the mortalities were 28.0%, 57.1% respectively. In case of the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, it was 112.±35.1 mm2 and 159.2±65.2 mm2 respectively. And the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of injected pine trees at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid were 0.61±0.0 mm2 and 8.1±12.4 mm2 and both mortalities were 23.1%. Although M. saltuarius adults, when tested with 1-year-old twig of a pine tree injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it but M. saltuarius adults tested with 2-year-old twig of the same pine tree were 2.0±3.7 mm2 and their mortalities were 53.8%, 61.5% respectively. We investigated insecticidal activities, the effects of feeding deterrence of acetamiprid for vector insects where fed twigs of injected pines by stop up hole with a cork or not, and the trunk injection to pine trees at a dose of 0.5, 1 ㎖ per ㎝ dbh of a pine tree with acetamiprid on the early June. As a result, all of the vector insects were not fed and the feeding area was within 11 ㎟ and the mortality of M. alternatus was 70%.
        12.
        2020.06 서비스 종료(열람 제한)
        Purpose: The purpose of this study is to provide fundamental information for professional sports and economy activation of cities, to explore mutual cooperative constructive relationship, and to investigate the Impact of Korean professional volleyball teams brand personality on city brand equity. Research design, data, and methodology: The study collected 500 survey responses and analyzed 478 surveys except for 22 which did not complete all items. For analyzing data, frequency, reliability, exploratory factor analysis, t-test, One-Way ANOVA, correlation, Multiple Regression were computed. Results: First, in difference in brand personality and city brand equity, due to gender, age, region of fan, significant difference were shown statistically in team image by gender, in honesty, interest and obdurability of brand personality by age, and in local community contribution, development possibility and sports facility of team image. Also, all factors show significant difference in region of fan. Second, regarding the impact of brand personality on city brand equity, honesty and capacity were shown to affect every factor of city brand equity, interest affected city image, and obdurability affected city perception. Conclusion: Professional teams need to develop win-win relationship with local community and seek to build positve image towards community fans via distinctive strategies for positioning.
        13.
        2015.09 서비스 종료(열람 제한)
        Hepatocyte-like cells (HLCs) derived from human pluripotent stem cells have received extensive attention in the development of drug screening and toxicity testing. However, it has been reported that stem cell-derived HLCs showed hepatic functions that were too limited to be of use in drug screening and toxicity testing, possibly due to the lack of sufficient intercellular communication under conventional two-dimensional (2D) culture conditions. Therefore, a 3D differentiation system may overcome the in vitro limitation of 2D culture to produce stem cell-derived hepatocytes with mature metabolic functions. In this study, the feasibility of using a silicone-based spherofilm, specifically designed to produce spherical cell clusters, to generate uniformly sized 3D hepatic spheroids from hESCs was investigated. Hepatic spheroids generated on the spherofilm showed more homogenous size and shape than those generated in conventional low-attachment suspension culture dishes. Results of immunohistochemical analysis showed that expression of the mature hepatic marker albumin (ALB) increased over time during the hepatic maturation process. Furthermore, the 3D culture system mimicked the in vivo 3D microenvironment. Laminin, which is an important component of hepatic ECM, was expressed in hepatic spheroids. The results of immunohistochemical analysis indicated that the 3D culture environment is capable of generating an in vivo-like microenvironment. In addition, quantitative PCR analysis showed that the mature hepatic marker ALB and cytochrome P450 (CYP) enzymes CYP3A4 and CYP3A7 were expressed at higher levels in 3D culture than in 2D culture. This indicates that the 3D culture system is suitable for hepatic maturation and that our size-controlled 3D culture conditions might accelerate hepatic function. These results suggest that 3D hepatic spheroids significantly enhance metabolic maturation of hepatocytes derived from hESCs