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.

Understanding the dispersion of xenon isotopes following a nuclear test is critical for global security and falls within the remit of both the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and the International Noble Gas Experiment (INGE). This paper aims to show if it is possible to discriminate the source of xenon releases based on the atmospheric dispersion of xenon isotopes using HYSPLIT. Using ORIGEN and SERPENT simulations, four released scenarios are defined with four different fractionation times (i.e., 1 hour, 1 day, 10 days, and 30 days) after a 1kt TNT equivalent 235U explosion event. These time-delayed release scenarios were selected to certify the possibility of mis-determining xenon release source. We use the Lagrangian dispersion model for atmospheric dispersion to predict the concentration distribution of xenon isotopes under each scenario. The model allows us to better understand how these isotopes would distribute over time and space, offering valuable data for real-world detection efforts. To our knowledge, there have been no researches on the analysis of xenon isotopic ratios considering atmospheric dispersion. In this work, we focused on the atmospheric dispersion using HYSPLIT to characterize the xenon isotopic ratios from nuclear tests. In addition, we compared the xenon isotopic ratios obtained from the atmospheric dispersion with those from ORIGEN calculations, which would be helpful to discriminate the source of the xenon releases.

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.

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.

PURPOSES : The objective of this study is to determine the characteristics of nitrogen oxide (NOx) concentration in an exclusive median bus lane station. The hourly variations of NOx concentration and the effect of traffic volume on NOx concentration were analyzed using NOx measurement data and the number of vehicles at the station. METHODS : Data were collected using the chemiluminescence method for NOx concentration. Atmospheric information and traffic volume of buses were collected from the Korea Meteorological Administration and Bus Information System, respectively. RESULTS : As a result, the NO2 concentration in the test section was found to have a strong correlation with those in the atmospheric measurement station located near the test-bed. In addition, the average NOx concentrations in the test section were significantly higher than those of the other monitoring stations due to bus emissions. The average NOx concentration in the exit section was higher than that in the entry section owing to the vehicle’s frequent stops and fuel consumption due to acceleration. During the measurement period, the average NOx concentration was measured as approximately 33 % higher in the exit section than in the entry section. In addition, the NOx concentration at the bus station was found to increase as the bus dwell time increased, rather than the number of bus passages. CONCLUSIONS : This study provides clear characteristics of the NOx correlations with traffic information in an exclusive median bus lane station. It was shown that the NOx concentration at the bus station increased as the number of passes and bus dwell time increased. According to the coefficient of determination, the dwell time is more closely correlated to the NOx concentration at the bus station than the number of bus passes, indicating that it is a better parameter for predicting NOx concentration at bus stations.

The pitch-based activated carbons were prepared with KOH/KMnO4 as a multiple function activation agent to increase the specific capacitance of a supercapacitor electrode active material. And the porous structure and electrochemical properties of activated carbon were analyzed on varying amounts of KMnO4. KMnO4 was decomposed into K2O, MnO, and O2 at the activation temperature of KOH, and MnO was introduced to activated carbon. K2O/ O2 reacts with a surrounding pitch to generate micropores and forms a pathway that exposes MnO to the outside. It also affects to the specific surface area of activated carbon like KOH chemical activation. The enhanced specific surface area and introduced MnO in activated carbon led to a 28.9% increase in specific capacitance.

본 연구에서는 다른 광환경에서 자란 긴산개나리(Forsythia saxatilis var. lanceolata) 줄기와 잎의 항산화물질 함량 및 활성을 분석하여 기능성 신소재로 활용하기 위한 기초자료를 마련 하고자 수행하였다. 삽목 후 3년생인 긴산개나리를 무작위로 채취하여 부위별로 분석한 결과, 긴산개나리 잎의 항산화물질 함량은 총 안토시아닌 함량과 총 플라보노이드 함량, 총 페놀 함량이 각각 68.8mg CGE/100g FW, 7405.0mg CE/100g FW, 4231.2mg GAE/100g FW로 줄기보다 높았으며, 항산화 활성 또한 294.3mg VCE/100g FW로 줄기보다 높은 것으로 조사되 었다. 이에 따라 긴산개나리의 항산화물질 함량과 활성간의 상관관계를 분석한 결과, 총 안토시아닌은 다른 요인 간의 상관관계가 없는 것으로 나타났으나 총 플라보노이드와 총 페놀은 서로 간에 0.05 유의수준 내에서 r=0.753으로 양의 높은 상관관계를 가지며, 총 플라보노이드와 총 페놀은 항산화 활성인 DPPH radical 소거활성과 0.05 유의수준 내에서 각각 r=0.753, 0.698 로 높은 양의 상관관계를 갖는 것으로 조사되었다. 이를 통해 긴산개나리의 총 페놀은 대부분 총 안토시아닌보다 총 플라보 노이드로 구성된 것으로 판단되고, 이러한 총 플라보노이드와 총 페놀이 항산화 활성에 기여하는 것으로 판단된다. 서로 다른 광환경에서 삽목 후 3년동안 생육한 긴산개나리의 부위별 항산 화물질 함량 및 활성을 분석한 결과, 총 안토시아닌, 총 플라보 노이드, 총 페놀은 반음지(42.83μmol･m-2 ･s-1 PPFD)보다 양지 (788.39μmol･m-2 ･s-1 PPFD)에서 생육한 긴산개나리의 잎에서 함량이 높은 것으로 조사되었으며, 항산화 활성도 반음지보다 양지에서 생육한 긴산개나리의 잎에서 높은 것으로 나타났다. 광환경에 따라 긴산개나리의 엽록소 함량을 조사한 결과, 엽록소 함량 또한 양지에서 생육한 긴산개나리 잎에서 높은 것으로 조사되었다. 이를 통해, 페놀화합물과 vitamin C 는 광합성 과정 중 합성되는 물질이기 때문에 반음지보다 광량이 많은 양지에서 생육한 긴산개나리의 잎이 항산화물질 함량과 활성이 높은 것으로 판단된다. 따라서, 긴산개나리는 줄기보다 잎에 항산화물질 함량 및 활성이 높아 천연항산화제로서 가능성이 있는 것으로 판단되며, 특히, 양지에서 생육한 긴산개나리의 잎이 반 음지에서 생육한 것보다 항산화물질 및 활성이 높기 때문에 기능성 소재로서 잠재적 활용 가능성이 높을 것으로 판단된다.

본 연구는 설문을 통해 ‘스마트 그린오피스(Smart Green Office)’에 대해 대중의 인식과 선호도를 알아보고, 활성화를 위한 기반을 마련하고자 수행하였다. 총 195명을 대상으로 설문조사를 진행하였으며, 실내식물에 대한 인식과 ‘스마트 그린오피스’의 인식 및 선호도에 대하여 조사하였다. 설문조사 결과, 설문에 참여한 대부분의 응답자들은 실내식물을 선호하며, 접근성과 필요성에 대해 긍정적으로 답변한 것으로 조사되었다. 응답자들이 실내식물을 통해 ‘공기 질 향상(52.0%)’ 및 ‘스트레스 해소(34.0%)’등 긍정적인 효과를 경험한 적이 있기 때문에 실내식물의 기능을 인지하고 필요성을 크게 인식하는 것으로 판단된다. ‘스마트 그린오피스’의 인지도에 대해 조사한 결과, 알거나 들어본 경험이 있는 사람은 15.4%로 적었으나 개념을 설명한 후, 필요성을 느끼고 설치를 원하는 응답자들 은 90% 이상으로 조사되었다. 응답자들은 ‘공기정화(83.6%)’ 기능 때문에 ‘스마트 그린오피스’ 도입 이 필요하다고 하였으며, 오피스 내 도입 시‘공기정화 식물(70.8%)’로 이루어진 벽면형태(41.0%)’를 선호하는 것으로 조사되었다. 또한, ‘비용 (45.6%)’과 ‘유지 관리(28.2%)’등의 문제가 ‘스마트 그린오피스’ 도입 시 고려하는 점으로 조사되었으며, 설치 시 비용은 ‘200만원 이하(56.4%)’와 ‘200~450 만원(38.5%)’을 선호하는 것으로 조사되었다. ‘스마트 그린오피스’의 인식 및 선호도와 더불어 비활성화에 대한 원인을 조사한 결과, ‘낮은 인지도’ 및 ‘스 마트 그린오피스’의 개념을 인지하지 못한 ‘불필요’가 각각 25.1%와 42.6%로 조사되었으며, ‘적극적인 마케팅 및 홍보 (46.2%)와 ‘실내식물에 대한 관심도 향상(38.0%)’이 이를 해결하기 위한 방법이라고 응답하였다. 따라서, ‘스마트 그린오피스’의 올바른 의미를 알리고, 공기정화 식물로 이루어진 벽면형태의 디자인 개발 및 모델 제시와 같이 ‘스마트 그린오피스’가 활성화될 수 있도록 홍보를 통한 다양한 정보 제공 등 여러 방안 모색이 필요할 것으로 판단된다.

본 연구는 금잔화를 꽃차로 이용하기 위해 열풍 건조 처리 시간에 따른 항산화 물질함량 및 항산화 활성을 분석하고, 최적 처리 시간을 구명하기 위해 수행하였다. 식용꽃 금잔화를 60℃에서 5시간, 10시간, 15시간 열풍건조 한 뒤 Hunter value를 측정하고 95% 에탄올을 용매로 하여 추출하였다. 항산화 물질인 총 폴리페놀, 총 플라보노이드, 총 카로티노이드 함량과 DPPH radical 소거 활성을 통한 항산화 활성, 이를 통한 항산화 물질 함량과 항산화 활성 간의 상관관계를 분석하였다. 처리시간이 증가함에 따라 Hunter value L 값과 +b값이 모두 감소하는 경향을 보였으며, 15시간 처리구에서 다소 많이 감소하였다. 또한, 항산화 물질 함량을 조사한 결과, 총 폴리페놀 함량은 처리 시간에 따른 차이는 없었으나 총 플라보노이드 함량과 총 카로티노이드 함량은 5시간과 10시간 처리시 함량이 다소 높았으며, 처리 시간이 증가함에 따라 감소하여 15시간 처리시 대조구와 차이가 없는 것으로 조사되었다. DPPH radical 소거 활성 분석 결과, 5시간과 10시간 처리시 대조구보다 활성이 높았으며, 총 카로티노이드가 DPPH radical 소거 활성 간의 상관관계가 높은 것으로 나타났다(p≤0.01, r=0.610). 따라서, 열풍건조한 금잔화는 총 카로티노이드가 항산화 활성에 기여하며, 5시간 및 10시간 열풍건조 처리가 금잔화의 항산화 물질 함량 및 활성 증가에 효과적인 것으로 판단되나 식물의 열처리 가공에 있어 오랜 시간은 내부 조직 및 항산화 물질 파괴에 영향을 미칠 수 있기 때문에 금잔화 열풍 건조 처리 시 5시간이 효과적일 것으로 판단된다.

The honey bee soluble acetylcholinesterase 1 (AmAChE1) is overexpressed under the overwintering and brood rearing-suppressed conditions. To investigate the role of AmAChE1 in regulating acetylcholine (ACh) titer, ACh concentrations both in the head (neuronal) and abdomen (non-neuronal) were analyzed. ACh titer was significantly lower in both tissues of worker bees under the overwintering and brood rearing-suppressed conditions compared to control bees. The expression levels of another two factors that regulate ACh titer, choline acetyltransferase (AmAChT) and acetylcholinesterase 2 (AmAChE2), were not altered as judged by qPCR and native PAGE, suggesting that the lower ACh titer was mainly regulated by AmAChE1. For precise verification of AmAChE1 as an ACh titer regulator, honey bees were put under brood rearing-suppressed condition to induce AmAChE1 and injected AmAChE1 dsRNA to knock down the gene. The ACh titer of AmAChE1-knocked down honey bees was 1.9 and 2.6 folds higher than that of control bees in head and abdomen, respectively. Taken together, in spite of its extremely low catalytic activity, the overexpression of AmAChE1 is likely to be related with the low level of ACh homeostasis, perhaps via ACh sequestration, under brood rearingsuppressed condition, and likely induce metabolic changes through ACh receptors-related pathways.

Small hive beetle (Aethina tumida) (SHB) is an invasive species to most northern hemisphere countries, including Korea. In an attempt to obtain basic information for efficient management of SHB, genes encoding conventional insecticide targets [voltage-sensitive sodium channel α-subunit (VSSC) and acetylcholinesterase (AChE)] were annotated and characterized following the analysis of whole transcriptomes of adults and larvae. A single VSSC gene was identified but no apparent mutations associated with pyrethroid resistance were detected. Genes encoding two AChEs (AtAChE1 and AtAChE2) were identified from the SHB transcriptome. AtAChE1 was determined to be the main catalytic enzyme, thereby being a toxicologically more relevant target. No apparent mutations associated with resistance to organophosphorus and carbamate insecticides was identified in the AtAChE1 gene, whereas the S238G mutation, originally identified from the Colorado potato beetle, was detected in the AtAChE2 gene.

The honey bee soluble acetylcholinesterase 1 (AmAChE1) is overexpressed under the overwintering and brood rearing-suppressed conditions. To investigate the role of AmAChE1 in regulating acetylcholine (ACh) titer, ACh concentrations in both the head (central nervous system) and abdomen (peripheral nervous system) were analyzed. ACh titer was significantly lower in both tissues of worker bees under the overwintering and brood rearing-suppressed conditions compared to control bees. Interestingly, the expression levels of choline acetyltransferase (AmChAT) and molecular marker genes of immune systems were significantly reduced in honey bee head under the same conditions. Taken together, ACh titer appears to be reduced via a cooperative interaction of the AmAChE1 overexpression and AmChAT underexpression and to be linked to reduced inmmune responses under the overwintering and brood rearing-suppressed conditions. The roles of AmAChE1 (with little catalytic activity) and AmChAT in the ACh homeostasis and signaling was discussed in the contexts of immune response and longevity regulation in honey bees.

Among two different acetylcholinesterase (AmAChE1 and AmAChE2) of the western honey bee, the soluble AmAChE1might be related with a stress response as judged from its over-expression in honey bee workers when brood rearingwas suppressed. In this study, to ensure the nature of AmAChE1 responding to stress factors, the expression patternsof AmAChE1 were investigated following various treatments, including varroa mite infestation, bacterial challenge, broodrearing suppression, thermal stresses, chemical treatments, ultraviolet B irradiation, starvation, water restriction and crowdingstress. In addition, transcription profiles of four heat shock protein genes known as general stress markers and vitellogeningene, which is induced in several stress conditions, were tested as positive references. In every tested condition, onlybrood rearing suppression and heat shock were related with the expression of AmAChE1.

We report on the dispersion state of partially reduced graphene oxide (PRGO) in organic solvents, namely methyl ethyl ketone, ethyl acetate, methylene chloride, toluene, and xylene, by controlling the carbon to oxygen (C/O) atomic ratio of the PRGOs. A two-phase solvent exchange method is also proposed to transfer PRGO from water to an aprotic solvent, such as methyl ethyl ketone. We achieve relatively good dispersion in aprotic and non-polar solvents by controlling the C/O atomic ratio of the PRGOs and applying the two-phase solvent exchange method. There is an increase in the glass transition temperatures with the dispersion of PRGOs into amorphous polymers, in particular a 4.4°C increase for poly(methyl methacrylate) and 3.0°C increase for polycarbonate. Good dispersion of PRGO in a nonpolar polymer, such as linear low density polyethylene, is also obtained.