The potential release of toxic metals such as Li, Ni, and Co into aquatic environments is increasing due to the growth of the lithium-ion battery (LIB) industry and the expansion of recycling processes. In this study, the 24-h acute toxicity of Li, Ni, and Co was evaluated in both single-metal exposures and binary mixture using Daphnia magna. Single-metal toxicity showed the highest toxicity for Co, followed by Li and Ni. Mixture toxicity results indicated antagonistic interactions in the Li-Ni and Li-Co combinations, whereas a strong toxicity enhancement was observed for the Ni-Co combination. Nonlinear interaction patterns dependent on fixed concentrations and concentration ratios were also identified. These findings highlight the limitations of simple additivity assumptions and provide fundamental data for mixture-based ecological risk assessment related to LIB recycling activities.

The impact of harvest time on the physicochemical properties and antioxidant activity of Seolhyang strawberry varieties was evaluated. The Hunter color value, which indicates redness on the surface of strawberries, was significantly higher for strawberries with a third flower cluster. Our results also revealed that the strawberry pH tended to increase significantly with extension of harvest time. Soluble solids in strawberries from the fifth flower cluster were significantly lower throughout the harvest period. Strawberries from the first flower clusters exhibited the highest acidity, while strawberries from the third flower clusters held the lowest acidity. Strawberry antioxidant properties assessment revealed that total polyphenol and anthocyanin content tended to increase with delay of harvest time. Vitamin C content tended to significantly increase with increasing flower cluster number until cluster 4. Fifth flower cluster strawberries showed decreased vitamin C. Sensory acceptability scores for second-flower cluster strawberries were significantly higher than those of the others for appearance, taste, and overall acceptability. This study confirmed important impacts of harvest time on the physicochemical and sensory properties of strawberries. We expect that this data can be used to guide the development of processed strawberry products.

‘Tracers’ are bullets that emit light at the backside so that the shooter can see the trajectory of their flight. These light-emitting bullets allow snipers to hit targets faster and more accurately. Conventional tracers are all combustion type which use the heat generated upon ignition. However, the conventional tracer has a fire risk at the impact site due to the residual flame and has a by-product that can contaminate the inside of the gun and lead to firearm failure. To resolve these problems, it is necessary to develop non-combustion-type tracers that can convert heat to luminance, so-called ‘thermoluminescence (TL)’. Here, we highly improve the thermoluminescence properties of MgB4O7 through co-doping of Dy3++Ce3+ and Dy3++Na+. The presence of doping materials (Dy3+, Ce3+, Na+) was confirmed by XPS (X-ray photoelectron spectroscopy). The as-synthesized co-doped MgB4O7 was irradiated with a specific radiation dose and heated to 500 °C under dark conditions. Different thermoluminescence characteristics were exhibited depending on the type or amounts of doping elements, and the highest luminance of 370 cd/m2 was obtained when Dy 10 % and Na 5 % were co-doped.

Bullets flying with a light from the back are called “tracers”. Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called “thermoluminescence (TL)”. This study aims to compare the TL emission of Dy3+, La3+ and Ho3+ doped MgB4O7 phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB4O7. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy3+, La3+ and Ho3+ (at different concentrations of 5, 10, 15 and 20 %) doped MgB4O7 were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

According to enhancement of roles and functions of enterprises’ distribution centers, recent trend of distribution centers are specialization and diversification which have generated lots of new distribution center building or expansion of the existing ones and led attention on stock transfer importance in case of distribution center relocation. This thesis is a study for how to reduce stock transfer leadtime in order to minimize business risk and how to increase inventory accuracy when stock ownership is transferred in case of distribution center relocation, and to provide inventory accuracy management methods and inventory in/out management types, detailed definition to evaluate level for inventory accuracy management and pros/cons by inventory in/out management type assuming ‘the higher inventory accuracy before stock transfer, the shorter stock transfer leadtime when distribution center is relocated'. This thesis provides detailed procedure to secure an absolute stock transfer leadtime and process to confirm hugh inventory accuracy by stakeholders which should be sloved by Task Force Team for stock transfer in case of distribution center relocation.

This study examined the effects of plums produced in Gimcheon area on the glucose and lipid metabolism in streptozotocin-induced diabetic rats. Male Sprague-Dawley diabetic rats were divided into four groups: control, diabetic control, Diabetes-low plum (containing 10% plum powder), and Diabetes-high plum (containing 20% plum powder). The animals were fed isocaloric experimental diets based on an AIN-76 diet for 6 weeks. Feed efficiency ratio (FER) of the diabetic groups were significantly lower than that of the control. On the other hand, among the diabetic groups, the FER of the high plum intake group was higher than that of the diabetic control. The liver weight per 100 g body weight of each group was similar but the liver weights tended to decrease as the amount of plum intake was increased. Kidney weight per 100 g body weight of the plum intake groups were significantly different compared to that of the diabetic control. The supplementation of plums lowered the fasting blood glucose level of the diabetic groups and improved the glucose tolerance, thereby lowering the glycosylated hemoglobin index. In addition, the supplementation of plum was lowered the blood total cholesterol concentration and increased the HDL-C/TC (%) significantly, thereby lowering the atherosclerotic index (AI) and hepatic peroxide level. A steady diet of plums produced in Gimcheon may be effective in controlling the blood glucose level and preventing chronic diabetes mellitus.

본 연구는 진동에너지를 흡수하기 위한 진동 금속 댐퍼의 구조 해석과 최적 설계를 수행한다. 고무 베어링, 마찰 또는 점성 댐퍼와 같은 다른 댐퍼와는 달리 이 금속제진장는 금속의 소성 변형과 그에 따른 히스테리시스 현상을 이용하여 구조물의 진동을 감소시킨다. 이 금속제진장치를 최적화 하려면 댐퍼를 통해 소성 변형을 얻는 것이 중요하다. 금속제진장치의 최적화 된 형상을 찾기 위해 형상 최적화 방법을 적용하였다. 또한 매개 변수화 체계에 따라 일부 최적의 모양을 찾을 수 있다.