• Journal of the korean society of oceanography
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• 제34권4호
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• pp.214-219
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• 1999

Cells of the dinoflagellate Gyrodinium impudicum form characteristic chains, which are associated with sugar accumulated on the cell surface. To resolve the relationship between chain-formation and cell surface sugar accumulation, confocal microscopy was used to observe sugar accumulation points in the vegetative cells and long chain-forming cells of G. impudicum cells treated with fluorescent-tagged ConA. In the stationary and exponential phases, both vegetative cells and chain-forming cells were similar to each other in fluorescent intensity. There was no evidence that chain-forming cells had a specific location for sugar accumulation on the cell surface. Most of the cells formed 2-cell chains one day after inoculation, but longer chains consisting of 4-8 cells increased markedly in 4day and 8 day cultures. Gyrodinium impudicum chains usually consist of more than four cells, and chains of 8 or even 16 cells can be observed in mature cultures. Temperature played an importantrole in chain-formation of the cells, threshold temperature for the development of long chain-formation was 19 $^{\circ}$C.

• 소성∙가공
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• 제16권8호
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• pp.614-620
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• 2007

Deformation characteristics and damage evolution during warm backward extrusion of bulk AZ31 Mg alloy were investigated using finite element analyses. AZ31 Mg alloy was assumed as a hardening viscoplastic material. The tensile tests of AZ31 Mg alloy in previous experimental works showed the ductile fracture even at the warm temperature of $175^{\circ}C$. In this study, damage evolution model proposed by Lee and Dawson, which was developed based on the growth of micro voids in hardening viscoplastic materials, was combined into DEFORM 2D. Effects of forming temperature, punch speed, extrusion ratio and size of work piece on formability in warm backward extrusion as well as on mechanical properties of extruded products were examined. In general, finite element predictions matched the experimental observations and supported the analyses based on experiments. Distributions of accumulated damage predicted by the finite element simulations were effective to identify the locations of possible fracture. Finally, it was concluded that the process model, DEFORM2D combined with Lee & Dawson#s damage evolution model, was effective for the analysis of warm backward extrusion of AZ31 Mg alloys.

• 방사성폐기물학회지
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• 제2권1호
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• pp.23-34
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• 2004

To validate the previous conceptual design of cover system, construction of the engineered barrier test facility is completed and the performance tests of the disposal cover system are conducted. The disposal test facility is composed of the multi-purpose working space, the six test cells and the disposal information space for the PR center. The dedicated detection system measures the water content, the temperature, the matric potential of each cover layer and the accumulated water volume of lateral drainage. Short-term experiments on the disposal cover layer using the artificial rainfall system are implemented. The sand drainage layer shows the satisfactory performance as intended in the design stage. The artificial rainfall does not affect the temperature of cover layers. It is investigated that high water infiltration of the artificial rainfall changes the matric potential in each cover layer. This facility is expected to increase the public information about the national radioactive waste disposal program and the effort for the safety of the planned disposal facility.

• The Plant Pathology Journal
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• 제28권2호
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• pp.172-184
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• 2012

An infection risk model for Phytophthora blight on chili pepper was developed to estimate the first date of disease occurrence in the field. The model consisted of three parts including estimation of zoosporangium formation, soil water content, and amount of active inoculum in soil. Daily weather data on air temperature, relative humidity and rainfall, and the soil texture data of local areas were used to estimate infection risk level that was quantified as the accumulated amount of active inoculum during the prior three days. Based on the analysis on 190 sets of weather and disease data, it was found that the threshold infection risk of 224 could be an appropriate criterion for determining the primary infection date. The 95% confidence interval for the difference between the estimated date of primary infection and the observed date of first disease occurrence was $8{\pm}3$ days. In the model validation tests, the observed dates of first disease occurrence were within the 95% confidence intervals of the estimated dates in the five out of six cases. The sensitivity analyses suggested that the model was more responsive to temperature and soil texture than relative humidity, rainfall, and transplanting date. The infection risk model could be implemented in practice to control Phytophthora blight in chili pepper fields.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3283-3290
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• 2010

The gas-phase dehydration of glycerol to acrolein was carried out over 10 wt % HSiW catalysts supported on different supports, viz. $\gamma-Al_2O_3$, $SiO_2-Al_2O_3$, $TiO_2$, $ZrO_2$, $SiO_2$, AC, $CeO_2$ and MgO. The same reaction was also conducted over each support without HSiW for comparison. Several characterization techniques, $N_2$-physisorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the temperature-programmed desorption of ammonia ($NH_3$-TPD), temperature-programmed oxidation (TPO) with mass spectroscopy and CHNS analysis were employed to characterize the catalysts. The glycerol conversion generally increased with increasing amount of acid sites. Ceria showed the highest 1-hydroxyacetone selectivity at $315^{\circ}C$ among the various metal oxides. The supported HSiW catalyst showed superior catalytic activity to that of the corresponding support. Among the supported HSiW catalysts, HSiW/$ZrO_2$ and HSiW/$SiO_2-Al_2O_3$ showed the highest acrolein selectivity. In the case of HSiW/$ZrO_2$, the initial catalytic activity was recovered after the removal of the accumulated carbon species at $550^{\circ}C$ in the presence of oxygen.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1992-1993
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• 2007

Decay processes of accumulated charge in e-beam irradiated polymers during elevating temperature are observed using pulsed electro-acoustic measurement system. Since the polymeric materials have many superior properties such as light-weight, good mechanical strength, high flexibility and low cost, they are inevitable materials for spacecrafts. In space environment, however, the polymers sometimes have serious damage by irradiation of high energy charged particles. When the polymers of the spacecraft are irradiated by high energy charged particles, some of injected charges accumulate and remain for long time in the bulk of the polymers. Since the bulk charges sometimes cause the degradation or breakdown of the materials, the investigation of the charging and the decay processes in polymeric materials under change of temperature is important to decide an adequate material for the spacecrafts. By measuring the charge behavior in e-beam irradiated polymer, such as polyimide or polystyrene, it is found that the various accumulation and decay patterns are observed in each material. The results seem to be useful and be helpful to progress in the reliability of the polymers for the spacecraft.

• 동아시아경상학회지
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• 제11권1호
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• pp.41-51
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• 2023

Purpose - The prior literature has shown that there is a lack of a complete assessment of the key decisions in cold chain logistics. Such a study is required to offer recommendations for research in this expanding but under-researched topic with potentially significant management ramifications. Research design, Data, and methodology - The current researcher accumulated peer-reviewed sources from databases to augment each chosen study's validity. Selection varied between seminal works and much of the existing literature. The selection process was consistent with using a content checklist that established the inclusion and exclusion criteria. Result - The research findings indicate total five solutions regarding better decision in Cold Chain Logistics (CCL), such as (1) Pricing Decision in Cold Chain Logistics, (2) Decision on Temperature Control Decision in Cold Chain Logistics, (3) Supply Chain Network Design in Cold Chain Logistics, (4) Decision on Minimizing Inventory in Cold Chain Logistics, (5) Decision on Logistics Distribution. Conclusion - Stability of a cold chain should be maintained from manufacture or via logistical components and cold logistics products are susceptible to several variables, such as temperature, and degradation can easily harm food supply, product prices, and human health. Product safety infractions substantially impact human health, among other losses linked with a functioning CCL.

• 한국정밀공학회지
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• 제10권3호
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• pp.97-106
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• 1993

This is the study on fracture life under the interaction of creep and fatigue. It is difficult to explain the interaction of the creep and fatigue with indication of frequency but the dependency of the time should be considered. The formulation of material varieties causing by interaction of creep and fatigue is required in the accumulative damage method. The strain range partition method requires some of modification corresponding to the changes in temperature and load. All of other method also comprehended with above mentioned problems. Generally, in this field, the variety of stress-strain and suitable parameter is required and connective study between the macro and micro results seems to be insufficient. The linear damage rule is acquiring the support generally but it requires modification in the hgigh temperature instruments. The variety of stress effecting on crack and variety of stress on the metallurgical side are considered to be problems in the future days.

• 한국작물학회지
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• 제55권3호
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• pp.214-219
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• 2010

지구온난화에 따른 북한지역의 식량작물 생산을 주축으로 하는 이모작의 특성을 평가하기 위해서 온난화의 지역적 특성, 겨울작물의 월동온도, 여름작물의 냉해유발온도 및 이모작 작부양식별 소요적산온도 확보 등 온열지표의 변화를 농업기후지대별로 검토한 결과는 다음과 같다. 1. 온난화의 지역적 특성 북한의 온난화는 과거(1973-1994)보다 최근(2002-2006) 들어 연간 평균기온 $3,271^{\circ}C$로 $233^{\circ}C$나 상승되었고 일평균기온은 $8.96^{\circ}C$로 $0.64^{\circ}C$ 증가되었다. 일평균기온의 지역간 변이는 아한대인 북부내륙고산지대의 삼지연에서 $1.06^{\circ}C$, 온대인 동해안중부지대의 장전에서 $12.26^{\circ}C$로 큰 변이를 보였다. 2. 겨울작물의 월동가능지역 확대 겨울작물의 월동온도를 기준으로 가을보리+벼 이모작 ($-13^{\circ}C$ 이상 지역) 가능지역의 분포는 과거 서해안과 동해안 및 서부중간지대의 일부에서 최근 들어 서부중간지대의 전역으로 확대되었고, 가을밀+벼 이모작($-15^{\circ}C$) 가능지역은 과거 서해안과 동해안 및 서부중간지 전역에서 최근 중부산간지대의 전역과 북부산간 일부지역까지 확대되었다. 3. 여름작물의 냉해우려지역 분포 7월중 일평균기온 $17^{\circ}C$이하의 장해형냉해 유발온도의 경과일수를 기준으로 냉해우려지역의 분포는 북부내륙고산지대에서 21-29일, 동북해안북부지대에서 8-10일, 동북해안남부지대에서 2-5일로 나타났다. 4. 이모작 적산온도 확보의 지역적 분포 월동작물 가을밀과 결합된 여름작물(벼, 옥수수 및 콩) 이모작을 가능케 하는 적산온도 $3,150^{\circ}C$ 이상 확보지역의 분포는 북부내륙고산지대를 제외한 북한 전역으로 확대되었고, 여름작물 봄감자와 결합된 벼, 옥수수 및 콩 등 이모작을 가능케 하는 적산온도 $2,650^{\circ}C$ 이상 확보지역의 분포는 일부 북부내륙고산지대 혜산지역까지 가능하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.43-52
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• 2015

The uranium removal capacity of radish sprouts (Raphanus sativus L.) in groundwater was calculated on the basis of the amount of uranium accumulated in the radish sprouts rather than the concentration in solution, of which process was very limited in previous studies. Continuous rhizofiltration clean-up system was designed to investigate the feasibility of radish sprouts, applying for uranium contaminated groundwater (U concentration: 110 μg/L) taken at Bugogdong, Busan. Six acrylic boxes (10 cm × 30 cm × 10 cm) were connected in a direct series for the continuous rhizofiltration system and 200 g of radish sprouts cultivars was placed in each box. The groundwater was flushed through the system for 48 hours at the constant rate of 5 mL/min. The rhizofiltration system was operated in the phytotron, of which conditions were at 25℃ temperature, 70% of relative humidity, 4,000 Lux illumination (16 hours/day) and 600 mg/L of CO₂ concentration. While 14.4 L of contaminated groundwater was treated, the uranium removal efficiency of the radish sprouts (1,200 g in wet weight) was 77.2% and their removal capacities ranged at 152.1 μg/g-239.7 μg/g (the average: 210.8 μg/g), suggesting that the radish sprouts belong to the group of hyper-accumulation species. After the experiment, the sum of U amounts accumulated in radish sprouts and remained in groundwater was 1,472.2 μg and the uranium recovery ratio of this rhizofiltration experiment was 92.9%. From the results, it was investigated that the radish sprouts can remove large amounts of uranium from contaminated groundwater in a short time (few days) because the fast growth rate and the high U accumulation adsorption capacity.