• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.344-353
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• 2018

The purposes of this study were to evaluate microleakage of Biodentine, one of the tricalcium silicate based pulp-capping materials, and to compare the shear bond strength between composite resin and Biodentine with different setting times. For microleakage evaluation, 70 bovine teeth were used. Cavities were formed on the labial surfaces and filled with Biodentine. The teeth were divided into seven groups, each consisting of 10 teeth. The specimens were prepared by applying the composite resin on the upper side after different setting times. To evaluate shear bond strength, 210 acrylic resin blocks with central grooves were prepared, and the grooves were filled with Biodentine. The acrylic resin blocks were divided into seven groups of 30 specimens each, and the specimens were prepared by applying the composite resin on the upper side after different setting times. In samples with setting time of 24 hours or longer period, the microleakage between composite resin and Biodentine was reduced significantly while the shear bond strength increased to offset the polymerization shrinkage of the composite resin. Setting Biodentine for more than 24 hours before composite resin restoration would lead to more favorable clinical result.

• Membrane Journal
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• v.8 no.2
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• pp.86-93
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• 1998

A permeation apparatus has been devdoped which could make the on-line measurements of both flux and permeate composition. Pervaporative experiment of a single component, i.e. water was performed by using poly(vinyl alcohol) membrane crosslinked with glutaraldehyde to confirm the validity of the apparatus. In the experiment, steady-state permeation was obtained in 15 minutes and the measurement could be completed within 20 minutes. A comparison of the on-line measurement was made with the fluxes measured simultaneously by the conventional method in which the permeates were collected by liquid nitrogen. The on-line measurement by the apparatus showed an excellent agreement with the conventional measurement within a difference of $\pm$2%. From the flux data with operating time, 3 kinds of diffusion coefficients of water $D_{slope}, D_{1/2}$, and $D_t$ were determined, which were also coincident with values in a literature. It was confirmed that accurate measurements of fluxes could be obtained from the apparatus.

• The Korean Journal of Zoology
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• v.10 no.1
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• pp.27-34
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• 1967

SM 계 자성 마우스를 대조군과 실험군으로 나누어,대조군에는 0.9% 생리식염수를 , 실험군에는 methylene blue(110 mg/kg, 식염수에 용해, pH 7.0)를 각각 피하주사하고, 40 분, 6 시간 또는 24시간후에 양군을 다같이 120 r X-선으로 일시 전신조사하였다. 조사후 21 시간에 걸쳐 albumin-globulin 비, 전혈청단백질 , 그리고 체중에 대한 간 및 신장중량비를 측정하여 조사전 처리시핵에 따른 methylene blue 의 방어효과를 조사하였다. 일반적으로 양군에서 조사후 일구간에 따라 2개의 변화가 나타났으며, 첫째는 1 일구에 , 둘째 상은 8 일구에 나타났다. methylene blue 처리는 이 두 개 상 일구에서 albumin -globulin 비의 증가성, 전혈청단백질 및 간장중량의 감소성에 대하여 큰 지체성을 나타냈다. 조사전 40 분 처리군에서 특히 현저한 방어작용이 있었으나 6 시간 및 24 시간전 처리구에서는 별 영향이 없었다.

• Polymer(Korea)
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• v.33 no.5
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• pp.501-508
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• 2009

The thermal degradation experiment of sodium salt of poly (${\gamma}$-glutamic acid) (PGGNa) has been carried out in both its solid phase and solution phase at the range of $57{\sim}120^{\circ}C$ and their molecular weight decreasing effect was analyzed as a function of time by means of viscometry and light scattering. Based on the solid phase degradation results, it was supposed that the bond scission rate in a polymer chain kept constant and that the bond scission was occurred on a randomly located position in a polymer chain. For the degradation in solution phase, it was also found that all data at various temperatures were dropped on a single master curve when the reduced time $t/t^*$ was used in the plot of the reciprocal intrinsic viscosity (or molecular weight). This degradation curve in solution phase could be expressed as the sum of a single exponential and a linear equation and especially, the single exponential character appeared only at the beginning stage. The activation energy was measured as $107{\sim}115$ kJ/mol in this study and agreed with the literature values.

• Food Science and Preservation
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• v.17 no.2
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• pp.261-266
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• 2010

Acidic hydrolysis conditions prior to HPLC analysis of plant flavonoids was investigated by response surface methodology (RSM), using leaves of Ginkgo biloba L. Ten hydrolysis conditions using 0.5-2.5 M HCl and 0.5-2.5 hr hydrolysis time were chosen to form a central composite rotatable design (CCRD), and optimization by RSM was achieved by measuring myricetin, quercetin, and kaempferol levels by HPLC. Optimum hydrolysis condition was 1.5 M HCl for 1.5 hr. The levels of flavonoids obtained under the condition were in good agreement with predicted maximum values, with yields of more than 95%. These optimum hydrolysis condition was applied to analysis of flavonoid content in the leaves of Camellia sinensis, Ficus carica, and Sageretia theezans.

• Journal of Wetlands Research
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• v.13 no.1
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• pp.129-137
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• 2011

The aim of this study is to evaluate the biodegradability of the micro-contaminant, clindamycin antibiotic, under nitrifying activated sludge (AS) condition. Based on the short-term clindamycin degradation batch test at an environmentally relevant concentration (10 ppb), clindamycin disappearance half-life ($t_{0.5}$) was estimated to be 9.1hrs under nitrification condition. However, biodegradation was slower (26.1 hrs) when nitrification was inhibited. Also, one clindamycin metabolite was detected under nitrification condition, but not under inhibited nitrification condition. Based on the mass spectra, the metabolite is suspected to be clindamycin-sulfoxide (m/z 441), which is known to have antimicrobial activity. The metabolite was not degraded during the long term batch study, suggesting that under the conditions tested, biodegradation of clindamycin in activated sludge systems is ineffective.

• Food Science and Preservation
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• v.14 no.2
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• pp.142-147
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• 2007

We optimized braising time to improve the storage quality of braised kidney beans. The beans were prepared with different heating times between 25 and 50 min. and then stored at $10^{\circ}C$ for 20 day. Physical, chemical, microbiological, and organoleptic quality indices were monitored throughout storage. Longer braising times yielded products with lower concentrated brine coverage. Bis resulted in higher soluble contents and slightly lower water activities. Excessive heating time exposed the kidney beans to air and caused rapid microbial growth on the surfaces of the beans, which negatively affected product quality. The longest heating time of 50 min. also resulted in a large increase in product hardness. A braising time of 30 min. was best for preservation, as good sensory quality was mainatained.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.373-376
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• 1998

직물에 있어서 경ㆍ위사의 밀도, crimp, cover factor, 직물의 두께, 무게 둥은 경ㆍ위사의 섬도, 직물의 패턴 등과 더불어 직물의 특성을 나타내는 기본적인 인자들이며 이러한 직물 구성 인자간의 관계에 대하여 Peirce의 연구[1] 이래 많은 연구가 이루어져 왔다. 그러나 이러한 인자들을 실제로 측정하기 위해서는 직물을 자르거나 분해하여야 하며, 측정에 많은 시간이 소요되고, 측정 방법이나 기기 또는 측정자에 따라 측정치에 차이가 나는 등의 단점이 있다. (중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.655-662
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• 1996

기술적으로는 다짐장비의 개선으로 성토다짐의 시공속도가 매우 빨라지고 있으나 국내에서 적용하고 있는 현장다짐 밀도 및 수분함량 측정 방법(KS F 2311 KS F 2306)$^{(1)}$ 은 신속한 측정을 어렵게 하고 있다. 본 연구는 외국에서 개발 현재 활발히 적용되고있는 방사성동위원소를 이용한 함수량측정기개발의 시작단계로 기본설계 결정을 목적으로 한다. 함수량 측정 RI계기의 원리를 먼저 살펴본 후 실험실 내에서 자연건조된 성토용 흙으로 다짐을 하여 공시체를 제작한 뒤, 실험실용 함수량측정 RI계기를 공시체위에 놓고 폴리에틸렌과 중성자 검출기의 개수를 변화시켜가며 일정시간동안 측정개수를 측정한 값을 분석한 결과 목표측정 시간을 1분으로 하였을 때 신뢰측정개수인 10,000개이상을 계측하면서도 경제적으로 최소인 중성자검출기의 개수는 2개, 폴리에틸렌의 두께는 7cm로 결정되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.447-449
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• 2011

본 연구의 목적은 복부 CT 영상에서 피부와 장기를 제외한 피하지방과 내장지방의 자동 분할이다. 복부지방은 피하지방과 내장지방으로 구분되는데 각 지방의 절대적 양과 더불어 내장 지방의 피하지방에 대한 비율역시 임상적으로 의미가 있다. 따라서 피하지방과 복부 지방의 양을 각각 측정한 후 그 비율을 계산하여 환자의 비만도를 알 수 있다. 이때 전문가의 수작업 없이 피하지방과 내장지방을 컴퓨터가 자동으로 분할하게 하여 빠른 시간에 효율적으로 지방의 양을 측정할 수 있도록 했다. 자동 분할 기법은 전문가의 보조 수단으로 오진단율을 줄이고 시간이 많이 소요되는 일을 간편하게 하는데 도움이 될 것으로 기대된다.