• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3658-3666
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• 2014

The presence of $^{238}U$, $^{232}Th$ and $^{40}K$, which are naturally residing radionuclides, in the ordinary soil of Busan, the 2nd largest city in Korea, was anlayzed and the residents' radiation exposure to ordinary soil was evaluated. Regarding the measurement methods, to conduct a detailed analysis of the naturally residing radionuclides in the soil of Busan, this study divided the 16 administrative districts into a lattice structure with 3 spots, and collected a total of 48 soil samples (July 2012 and April 2013). ICP-MS was used to analyze the concentration of the radioactivity of $^{238}U$ and $^{232}Th$ in the soil, and a HpGe detector, a gamma ray detector, was used to analyze the radioactivity of $^{40}K$. The measurement values of this study were compared with the concentration of radioactivity of East Asian regions. The concentration of $^{238}U$ nuclides in Korea was lower than the mean, whereas the concentration of $^{232}Th$ and $^{40}K$ nuclides was higher than the mean. The higher mean concentrations of $^{232}Th$ and $^{40}K$ than the mean were attributed to the many granite areas that contain a great deal of naturally occurring radionuclides.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.121-129
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• 2004

Anaerobic digestion is the most common process for sewage sludge stabilization and has benefits of VS reduction and biogas production. Many pretreatment methods have been studied to improve hydrolysis rate because the rate of sewage sludge degradation is slow in anaerobic digestion. This study mainly focused upon the effects on disintegration of sewage sludge by ultrasonic pretreatment according to the variation of acoustic density and duration of sonication time. In this study, acoustic density has been changed as follows : 33W/L, 70W/L, 88W/L, 139W/L in case of 40 kHz with the test time changes of 10min, 20min, 25min, 30min and 40min. In the comparison of $SCOD_{Cr}/TCOD_{Cr}$ variation for excess sludge and mixed sludge disintegration, the rates of $SCOD_{Cr}/TCOD_{Cr}$ have been increased in the condition of denser acoustic density and longer sonication time with acoustic frequency of 40kHz. The pH of the excess sewage sludge and mixed sewage sludge has been decreased in the condition of denser acoustic density and longer sonication time with acoustic frequency of 40kHz.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.76-85
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• 2008

Biological nutrient removal (BNR) sludge was added to a sequencing batch reactor (SBR) in the addition ratios of 0%, 20%, 40%, 50% while observing the variation of nutrient removal characteristics and microorganism groups. When the BNR sludge was added in a ratio over 40%, the characteristics of EBPR (enhanced biological phosphorus removal) was shown at the 27 days. However, a distinct BNR was not shown when the addition ratio of BNR sludge was lower than 40%. The organic removal efficiency were shown as 90% in all SBRs irrespective of the addition ratio of BNR sludge. At the 27 days, the phosphorus removal efficiencies were shown as 40%, 55%, 77% and 69%, respectively, according to the addition ratio of BNR sludge. Overall, efficient nitrification and phosphorus removal was shown when the added BNR sludge ratio was over 40%.

• ETRI Journal
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• v.30 no.2
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• pp.275-281
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• 2008

A 40 Gb/s clock and data recovery (CDR) module for a fiber-optic receiver with improved phase-locked loop (PLL) circuits has been successfully implemented. The PLL of the CDR module employs an improved D-type flip-flop frequency acquisition circuit, which helps to stabilize the CDR performance, to obtain faster frequency acquisition, and to reduce the time of recovering the lock state in the event of losing the lock state. The measured RMS jitter of the clock signal recovered from 40 Gb/s pseudo-random binary sequence ($2^{31}-1$) data by the improved PLL clock recovery module is 210 fs. The CDR module also integrates a 40 Gb/s D-FF decision circuit, demonstrating that it can produce clean retimed data using the recovered clock.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.355-362
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• 1987

본 실험의 목적은 치아 회분이 입자 크기에 따라 골형성에 어떠한 영향을 주며 순수 합성수산화 apatite인 calcitite와는 어떠한 차이가 있는가를 평가하기 위하여 수행하였다. 이를 위하여 200mesh와 40mesh의 치아 회분말과 40mesh calcitite를 잡종견의 신선한 발치와에 매식후 1주, 2주, 3주, 4주에 각각 희생하여 임상, X-선상 및 현미경적으로 관찰한 바 다음과 같은 결론을 얻었다. 1. 모든 경우에 조직의 거부반응이 없었다. 2. 40mesh치아 회분의 경우가 200mesh의 치아회분의 경우 보다 골 형성 능력이 현저히 높았다. 3. 40 mesh 치아회분과 calcitite 모두 비교군에 비하여 골 형성이 지연되었다. 4. 40 mesh 치아 회분과 calcitite의 골 형성 능력은 유사하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.49-56
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• 2019

This experiment was conducted to select an optimum application rate of blended biochar pellet as slow release fertilizer during cabbage cultivation. The blended biochar pellet made with a combination(4:6) of biochar and pig manure compost with unloading N, P, K solutions for adjusting about 9% of total nitrogen(TN). The treatments were consisted of the control as recommended application rates for cabbage cultivation in National Institute of Agricultural Sciences, N 40%, N 40% and 0.07M MgO and N 60 % of the blended biochar pellet, respectively, based on nitrogen application of recommended rates to cabbage cultivation. Changes of $NH_4-N$, $NO_3-N$, $P_2O_5$ and $K_2O$ concentrations in the soil and growth characteristic and yield components were investigated and observed during the cabbage cultivation. The experimental result shown that contents of $NH_4-N$, $NO_3-N$ and $K_2O$ of soil in the N 40% were significantly difference(p<0.01) with the control. $P_2O_5$ concentrations of soil in the N 40% were highest among the treatments. The fresh weight per cabbage in the N 40% was not significantly different(p>0.05) from the control, but in the N 40% and 0.07M MgO and N 60% was lower than that of the control. It was considered that an optimum blended biochar application rate for cabbage cultivation was 40% of recommended nitrogen application.

• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.161-170
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• 2005

This study was performed to examine immuno-regulatory activities of Ehpedrae Sinica STAPF, Rubus Coreanus Miq. and Angelica gigas Nakai extracts in conbination with ultrasonification. The extract yields of plants were the highest in the extraction system of $60^{\circ}C$ and 40 kHz of ultrasonification. The immune cell growth ratio of human immune B and T cells was increased compared to other fractions by the water fraction of the plants at $60^{\circ}C$ and 40 kHz. The water fractions of the plants at $60^{\circ}C$ and 40 kHz increased the specific secretion of IL-6 and $TNF-{\alpha}$ of human immune B and T cells compared to other fractions of the plants. The water fraction of Ehpedrae Sinica STAPF among the plants was observed to show the highest specific secretion of IL-6 and $TNF-{\alpha}$. Also, NK-92 MI cells growth was increased in adding the water fractions of the plants at $60^{\circ}C$ and 40 kHz. The water fraction of Ehpedrae Sinica STAPF among the plants showed the highest in NK-92 MI cell growth ratio. The differentiation activity of the HL-60 cells significantly increased in adding the water fraction of Ehpedrae Sinica STAPF compared to other fractions of the plants. These results suggest that the water fractions of the plants in extraction system of temperature $60^{\circ}C$ and ultrasonification 40 kHz have marked useful immuno-stimulatory activities.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.1
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• pp.41-49
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• 1996

본 연구는 체외수정에 의해 생산된 생쥐 배반포기배를 vitrification 방법으로 동결보존하였을때 높은 생존율을 얻기 위한 적정조건을 검토하고자 실시하였다. 배반포기배를 생산하기 위하여, B6CBA F1 (C57BL/6, (표현불가)${\times}CBA/N$, (표현불가)) 계통의 생쥐 미수정란에 $1{\times}10^6$ spermatozoa/ml 농도의 정자로서 수정을 유도하였으며, 이후 $37^{\circ}C$, 5% $CO_2$배양기내에서 96시간동안 체외배양하였다. 배양 4일째의 배반포기배는 발달상태에 따라 early, middle 그리고 hatching blastocysts로 구분하였다. 본 실험에 사용된 동결보존액은 30% Ficoll과 0.5mol의 sucrose가 첨가된 mDPBS 용액에 40%의 ethylene glycol를 첨가한 EFS 40 (Zhu et al., 1993) 이었고, 수정란은 $25^{\circ}C$의 상온에서 먼저 20% ethylene glycol에 노출된 후 EFS 40 용액으로 옮겨 액체질소에 침지하는 2단계 동결법에 의해 동결보존되었으며, 급속융해하여 다음과 같은 결과를 얻었다. 1. 체외수정율과 배양 4일째 배반포기까지의 배발달율은 각각 89.4%와 86.1%였다. 2. 20% ethylene glycol에서 5분간 평형된 후 EFS 40 용액에 냉동보존된 후 융해된 난자의 생존율은 20% ethylene glycol에 0, 1, 3분간 평형된 난자의 생존율에 비해 유의하게 높았다. 3. 배반포기배를 20% ethylene glycol에서 5분간, EFS 40 용액에 1분간 차례로 노출한 다음 체와배양하였던 바, 배양 24시간째 생존율은 $82.9%{\sim}88.4%$ 였다. 본 연구 결과, 체외수정, 배양된 생쥐 배반포기배는 20% ethylene glycol과 EFS40에 대한 노출만으로는 난자의 생존성에 나쁜 영향을 미치지 않는 것으로 미루어 보아 배반포기배의 초자화 동결이 가능함을 시사하였다. 따라서 동결 융해 후 높은 생존율은 상온에서 난자를 2단계 즉, 20% ethylene glycol에 5분간 평형시킨 후 EFS 40 용액에 노출하여 1분내에 LN2에 직접 침지하는 간편한 동결방법으로 얻을 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2865-2871
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• 2012

In this study, the fracture behaviour of DCB(double cantilever beam) specimen with aluminum foam composite materials is analyzed by simulation. By comparing the analysis results with two models of 25 mm and 40 mm, the model with thickness of 25 mm is weaker than 40 mm at fatigue life and damage. Two models are unfavorable at 'SAE Transmission' in case of nonuniform fatigue load and rainflow matrices are weakest at 'SAE Bracket history'. In damage matrices, the model with 25 mm of thickness is weaker than the model with 40 mm of thickness but the model with 40 mm of thickness relative damage possibility is higher than in case of 25 mm. As two models are safest at 'SAE Transmission', the relative damage becomes the lowest value from 1.1 to 1.8 %. The mechanical property can be investigated by applying these analyses results with the real composite structure bonded with adhesive and analyzing fracture behaviour.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.123-127
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• 2010

Attractiveness of different amounts of methyl (E,E,Z)-2,4,6-decatrienoate, the aggregation pheromone of brown-winged stink bug, Plautia stali (Hemiptera: Pentatomidae), was tested using different kinds of dispensers. A lure filled with hexane was used as a control treatment. There were no differences in the attractiveness of the pheromone to P. stali and Halyomorpha halys among dispensers (polyethylene-vial, rubber septum, and polyethylene tube). Traps baited with 7, 20, 40, 50, and 60 mg of pheromone were tested for their attractiveness. For females, the 40 mg trap attracted highest number of P. stali, even though there were no significant differences among pheromone amounts. For males, the 40 and 50 mg traps attracted significantly more bugs than the 7, 20, and 60 mg traps and the control traps. Based on these results, the pheromone dispenser impregnated with 40 mg of pheromone will be practical in monitoring P. stali in the field.