• 설비공학논문집
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• 제28권8호
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• pp.331-336
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• 2016

This study presents a coolant density calculation device and its corresponding method by using a mass flowmeter and the LabVIEW program. The method can be easily measured with a mixture of coolant and by calculating the percentage of ethylene-glycol without additional investment. The cooling water is very important in a vehicle to protect the engine, and the cooling performance is affected by the mixture concentration and coolant density. The coolant density calculation device measures the mixed concentration in the anti-freeze cooling mixture made from distilled water and ethylene-glycol in real time with the mass flowmeter that is commonly attached to the radiator or heater core. The calculation program for the mixture concentration percentage was developed using the LabVIEW software. The correlation between experimental results and the calculation was conducted for a range of temperature from 40 to $90^{\circ}C$ and by varying the mixture ratio of distilled water and ethylene-glycol. As a result, the anti-freeze coolant concentration in the volume percentage is able to monitor the coolant density in a timely basis by implementing a mixture concentration calculation program without the need for additional equipment investment. The results of the calculation for the mixture concentration level show a maximum 2.7% deviation compared to the experimental results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.160-165
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• 1999

Osmotic pressure induced by semi-permeability of hardened cement pasts and cement mortar was studied, which was considered to be a cause of failure such as separation and blistering of floor coatings or wall coatings from the concrete substrate. The specimens with a water cement ratio of 45, 60 and 75% were installed between the solution of sodium chloride and distilled water. First, we measured water flux from distilled water to sodium chloride and the ion flux of Na+ and Cl- through the specimens. Then, we measured osmotic pressure induced by semi-permeability of the specimens using an apparatus which was specially developed for this study. It was made clear that hardened cement paste and cement mortar have properties of semipermeability, and the osmotic pressure is closely related to their water cement ratio. Finally, we calculated the osmotic pressure according to Staverman's equation, which was obtained for organic membranes, and tried to explain quantitatively the observed pressure.

• Preventive Nutrition and Food Science
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• 제6권4호
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• pp.224-229
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• 2001

We investigated the effects of bean sprouts (Glycine max), dropwort (Oenanthe javanica), and radish (Raphanus sativus var. hortensis for. acanthiformis) extracts on alcohol dehydrogenase (ADH). The extracts from three kinds of vegetables were prepared by extracting with boiling water, distilling water, and ethyl alcohol. Among extracts, boiling water extract showed the highest activating effect on ADH, respectively and distilled water extract had a greater effect on ADH activation than that of alcohol extract. The ADH facilitating effect of bean sprout extract by distilled water was significantly higher than dropwort or radish, hut the effect of the bean sprout extract by ethyl alcohol was lower than others. The facilitating effect on ADH of mixture extracts of bean sprout and dropwort were mixed at 1 : 1 mixture of boiled-water extract showed the highest effectiveness. And bean sprout extract separated below 3000 molecular weight (MW) range of extract fraction had greater ADH activity than large MW parts.

• 한국가시화정보학회지
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• 제20권3호
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• pp.117-127
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• 2022

The present study has investigated the performance of hydrogen gas generators for inhalation purposes based on polyelectrolyte membrane water electrolysis (PEMWE). The system applied two watering methods. One is pumped water (pumping system) and the other is gravity-fed water without a pump (non-pumping system). The cell efficiencies were compared by measuring the cell voltage and temperature in the hydrogen gas generator, respectively. The results show that the cell voltage and temperature increase with the cell current. The cell temperature is lower in the pumping system than that in the non-pumping system at a given cell current. Even though the amount of hydrogen production is the same regardless of the pumping system, the cell efficiency of the hydrogen gas generator in the non-pumping system is better than that in the pumping system.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
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• pp.302-302
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• 2011

• The Journal of Advanced Prosthodontics
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• 제8권5호
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• pp.333-338
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• 2016

PURPOSE. The aim of this study was to compare the effects of different denture cleansers on the surface roughness and microhardness of various types of posterior denture teeth. MATERIALS AND METHODS. 168 artificial tooth specimens were divided into the following four subgroups (n=42): SR Orthotyp PE (polymethylmethacrylate); SR Orthosit PE (Isosit); SR Postaris DCL (double cross-linked); and SR Phonares II (nanohybrid composite). The specimens were further divided according to the type of the denture cleanser (Corega Tabs (sodium perborate), sodium hypochlorite (NaOCl), and distilled water (control) (n=14)) and immersed in the cleanser to simulate a 180-day immersion period, after which the surface roughness and microhardness were tested. The data were analyzed using the Kruskal-Wallis test, Conover's nonparametric multiple comparison test, and Spearman's rank correlation analysis (P<.05). RESULTS. A comparison among the denture cleanser groups showed that NaOCl caused significantly higher roughness values on SR Orthotyp PE specimens when compared with the other artificial teeth (P<.001). Furthermore, Corega Tabs resulted in higher microhardness values in SR Orthotyp PE specimens than distilled water and NaOCl (P<.005). The microhardness values decreased significantly from distilled water, NaOCl, to Corega Tabs for SR Orthosit PE specimens (P<.001). SR Postaris DLC specimens showed increased microhardness when immersed in distilled water or NaOCl when compared with immersion in Corega Tabs (P<.003). No correlation was found between surface roughness and microhardness (r=0.104, P=.178). CONCLUSION. NaOCl and Corega Tabs affected the surface roughness and microhardness of all artificial denture teeth except for the new generation nanohybrid composite teeth.

• 폴리머
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• 제26권2호
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• pp.185-192
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• 2002

Polymeric 4,4'-diphenylmethane diisocyanate (PMDI), polyether polyol,1,4-butane diol, silicone surfactant와 발포제로 물을 사용하여 경질 폴리우레탄 폼 (PUF)을 제조하였다. PUF의 밀도는 0 php (parts per hundred polyol by weight)의 부탄다이올 양에 대하여 물의 양이 0.5~3.0 php로 증가함에 따라 173.7~41.7 kg/㎥로 감소하였다. PUF의 셀 크기는 10 php의 부탄다이올 양에 대하여 물의 양이 0.5~3.0 php로 증가함에 따라 115-258 $mu extrm{m}$로 증가하였다. PUF의 압축강도 측정 결과, 동일 밀도의 PUF에 대하여 압축강도는 물의 양이 증가함에 따라 증가하였다. 계면활성제가 PUF의 물성에 미치는 영향에 관한 연구에서, PUF의 셀 크기가 계면활성제 첨가량이 0~0.33 php로 증가함에 따라 360-146 $mu extrm{m}$로 감소하였으나 0.33 php 이상의 계면활성제 첨가량에 대해서는 더 이상의 셀 크기 변화가 관찰되지 않았다.

• 원예과학기술지
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• 제17권6호
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• pp.758-760
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• 1999

몇가지 전처리제와 절화장미에 효과적인 보존용액으로 알려진 HQS+sucrose+ethionine 혼합액을 병행 처리하여 절화수명과 품질을 비교함으로써 절화장미의 관상가치를 향상시키고자 본 실험을 수행하였다. 절화수명은 증류수에 보존시에는 전처리 효과가 없었으며, HQS+sucrose+ethionine 용액에 보존하였을 때에는 aluminum sulfate 혼합액과 NaOCl 전처리에서 수명이 연장되었다. 흡수량은 증류수에 보존한 처리구에서 높은 경향을 보여 생체중과 반대의 결과를 나타냈다. 생체중은 STS+sucrose 전처리를 제외하고는 HQS+sucrose+ethionine 혼합액에 보존시 증류수보다 증가하였다. 꽃목굽음은 HQS+sucrose+ethionine 용액에 보존했을 때에는 모든 전처리에서 증류수보다 지연되는 경향을 보였으며 특히 aluminum sulfate 혼합액 전처리에서는 수명 종료시까지 꽃목굽음 현상이 거의 나타나지 않았다. 화경과 꽃잎의 건물중은 STS+sucrose 전처리를 제외하고는 처리간 차이가 없었으며, 보존용액에 있어서는 HQS 혼합액이 증류수보다 증가하는 경향을 보였다. 화색은 L값과 a값은 처리간 차이가 없었 으나 b값은 증류수에 보존한 처리구에서 최초의 값에 비해 낮게 나타났다.

• 한방재활의학과학회지
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• 제25권2호
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• pp.73-80
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• 2015

Objectives To assess the safety of Shinbaro3 Pharmacopuncture by analyzing the potential single-dose intramuscular toxicity of Shinbaro3 Pharmacopuncture at various dose levels in SD (Spraque-Dawley) rats and Beagle dogs. Methods For evaluation of single-dose intramuscular toxicity of Shinbaro3 Pharmacopuncture, 40 SD rats (20 male and 20 famale) and 4 Beagle dogs (2 male and 2 female) were used. The rats were divided in four groups of 10 each, and treated intramuscularly with Shinbaro3 Pharmacopuncture at doses of 0.3, 0.6 and 1.2 mg/kg in distilled water, and distilled water as a vehicle control group, respectively. The Beagle dogs were divided into two groups of 2 each, and treated intramuscularly with Shinbaro3 Pharmacopuncture at doses of 0.15, and 0.3 mg/kg in distilled water, respectively, and signs of toxicity were observed. After a wash-out period of 3 days, the procedure was repeated with Shinbaro3 Pharmacopuncture at doses of 0.6, and 1.2 mg/kg in distilled water, respectively. Mortality, body weight changes, and necropsy findings were examined during the study period. Results There were no mortalities in either the SD rats or Beagle dogs. There were also no significant differences in adverse effects, body weight, or necropsy findings between the Shinbaro3 Pharmacopuncture and control groups. Conclusions There results suggest that the lethal dose 50 ($LD_{50}$) and approximate lethal dose (ALD) value of the test substance Shinbaro3 Pharmacopuncture are higher than 1.2 mg/kg in SD rats and Beagle dogs.

• Macromolecular Research
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• 제17권1호
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• pp.44-50
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• 2009

Rigid polyurethane foams (PUF)s were synthesized with environmentally friendly blowing agents such as a cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only for four different silicone surfactants having different silicone/polyether ratios. An attempt was made to reduce the thermal conductivities of the PUF samples by varying the concentration and the silicone/polyether ratio of the various silicone surfactants. The scanning electron microscopy (SEM) results indicated an optimum concentration of the silicone surfactant of about 1.5 to 2.5 phpp for various surfactants to reduce the cell size and lower the thermal conductivity. The silicone surfactant having a higher silicone/polymer ratio showed a smaller cell size and, therefore, demonstrated the lower thermal conductivity of the PUF samples. From the relation between the thermal conductivity and the cell size of the PUF samples, the smaller cell size improved the thermal insulation property of the rigid PUF for both the PUF samples blown by the cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only. If the blowing agent is fixed, then the cell size is an important factor to decrease the thermal conductivity of the PUF samples. These results indicated that rigid PUF samples having lower thermal conductivity can be obtained by choosing a silicone surfactant containing a higher silicone/polyether ratio, as well as an optimum content of the surfactant.