• 공업화학
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• 제3권4호
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• pp.639-648
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• 1992

시멘트 수화물(CH)을 모르타르 콘크리트용 방수제 또는 고무 플라스틱용 충전제로 활용하기 위하여 스테아린산(SA)으로 처리하고 FT-IR, TGA, SEM, XRD, 접촉각층정기 등을 이용하여 CH-SA compound의 결합특성과 발수성을 측정하고, CH-SA compound를 레미탈에 사용하여 레미탈의 방수성을 알아 본 결과는 다음과 같이 요약된다. 1) 시멘트 수화물에 스테아린산을 2.0%이상만 처리하면 물레 대한 접촉각이 $120^{\circ}$이상으로 증가되면서 강한 발수성을 나타낸다. 2) 시멘트 수화물에 처리된 스테아린산은 스테아린산염 형태로 시멘트 수화물 표면에 고정된다. 3) 시멘트 수화물에 스테아린산을 5~10%처리한 CH-SA compound를 레미탈 중량의 3~6%정도 사용하면 레미탈의 압축강도는 5%정도 증가되며, 흡수비와 투수비는 각각 25%이하로 격감되어서 우수한 방수성을 나타낸다.

• 한국식품과학회지
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• 제20권3호
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• pp.344-349
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• 1988

분획(分劃)된 대두(大豆) 7S 및 11S 단백질(蛋白質)은 단백가수분해(蛋白加水分解) 효소(酵素)(alcalase 및 pronase)로 1시간(時間)동안 가수분해(加水分解)하였을 때 사용(使用)된 효소(酵素) 및 단백질(蛋白質) 종류(種類)에 관계없이 pH 5에서 용해도(溶解度), 열응고성(熱凝固性) 및 $Ca^{++}$에 대한 내침전성(耐沈殿性)은 상당히 증가(增加)에멀젼 활성 및 거품 안정성(安定性)은 감소(減少), 에멀젼 열안정성(熱安定性) 및 동점도(動粘度)는 거의 변화(變化)되지 않았다. 그러나 용해도(溶解度)에서 7S 단백질(蛋白質)은 pH 6에서 11S 단백질(蛋白質)은 pH 4에서 감소(減少)하였으며 또한 11S 단백질(蛋白質)은 유흡수성(油吸收性) 및 거품 형함능(形咸能)에서 가수분해(加水分解)에 의하여 증가(增加)하였으나 7S 단백질(蛋白質)은 거의 변화(變化)하지 않았다.

• Applied Biological Chemistry
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• 제47권3호
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• pp.361-365
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• 2004

키틴, 키토산 및 그 유도체의 토양처리와 종자 피복 등이 토마토 생육에 미치는 효과를 조사하고 분석하였다. 키틴과 그 유도체의 토양 처리는 토마토 초기 생육을 촉진하였으며, 키틴과 키토산을 토양에 혼화 처리한 경우 그 효과가 가장 탁월하였다. 이들의 처리는 토마토 근부의 생육을 촉진하였다. 토마토 식물체 중의 무기성분을 분석하여 이들의 처리효과를 분석하였던 바, 키틴 키토산의 처리는 질소와 칼륨의 흡수를 촉진하였으며 칼슘의 흡수를 억제하였다. 그러므로 이들은 식물의 무기양분 흡수의 조절을 통하여 생육을 촉진하는 것으로 판단하였다.

• 대한한의학회지
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• 제24권3호
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• pp.11-22
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• 2003

Objective : As the average span of human life extends, more and more people are at risk of developing osteoporosis, one of the typical diseases of the aged. This thesis presents the effects of Jeungikgwiryon-tang (Tsengikueijung-tang) on bone density, bone biochemical markers, and fetal calvarial cells (FCC) of Sprague Dawleys (S.D.) rats that have induced osteoporosis. The purpose is to see how Jeungikgwiryon-tang (Tsengikueijung-tang) reduces osteoporosis symptoms. Methods : In the first experiment Sprague Dawleys rats were administered Jeungikgwiryon-tang (Tsengikueijung-tang) for 70 days, once a day. Two different doses were used, creating high-dosed and low-dosed groups. The results were compared with a control group. In the second experiment, Jeungikgwiryon-tang (Tsengikueijung-tang) was applied to fetal calvarial cells (FCC) obtained from fetuses inside pregnant Sprague Dawleys rats. The FCCs from high-dosed and low-dosed groups were compared with those from a control group. Results : 1. Bone densities in Groups A and B increased significantly from a control group. 2. Bone ash densities in Group A showed substantial increase. 3. Calcium and phosphorus in bones in Group A increased significantly. 4. Activity of fetal calvarial cells' division in Groups A and B increased significantly from a control group, and ALP of fetal calvarial cells' formation in Group A increased significantly. 5. Protein and collagen levels of fetal calvarial cells in Group A increased significantly. Conclusion : It was found that Jeungikgwiryon-tang (Tsengikueijung-tang) has a tendency to make significant increases in bone densities by enhancing bone formation and by retarding bone absorption. It was concluded that Jeungikgwiryon-tang (Tsengikueijung-tang) activates osteoblast cells effectively.

• Computers and Concrete
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• 제13권6호
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• pp.739-748
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• 2014

In this article, by using experimental studies and artificial neural network has been tried to investigate the use of nano-silica as concrete admixture to reduce alkali-silica reaction. If there are reactive aggregates and alkali of cement with enough moisture in concrete, a gel will be formed. Then with high reactivity between alkali of cement and existence of silica in aggregates, this gel will expand by absorption of water, and causes expansive pressure and cracks be formed. At the time passes, this gel will reduce both durability and strength of the concrete. By reducing the size of silicate to nano, specific surface area of particles and number of atoms on the surface will be increased, which causes more pozzolanic activity of them. Nano-silica can react with calcium hydroxide ($Ca(OH)_2$) and produces C-S-H gel. In this study, accelerated mortar bar specimens according to ASTM C 1260 and ASTM C 1567, with different mix proportions were prepared using aggregates of Kerman, such as: none admixture and plasticizer, different proportions of nano-silica separately. By opening the moulds after 24 hour and curing in water at $80^{\circ}C$ for 24 hour, then curing in (1N NaOH) at $80^{\circ}C$ for 14 days, length expansion of mortar bars were measured and compared. It was noted that, the lowest length expansion of a specimens shows the best proportion of admixture based on alkali-silica reactivity. Then, prediction of alkali-silica reaction of concrete has been investigated by using artificial neural network. In this study the backpropagation network has been used and compared with different algorithms to train network. Finally, the best amount of nano silica for adding to mix proportion, also the best algorithm and number of neurons in hidden layer of artificial neural network have been offered.

• 한국축산식품학회지
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• 제30권3호
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• pp.443-448
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• 2010

유제품, 김치 및 신생아 분변 등에서 유산균을 분리하여 우유 casein을 분해시켜 배양상등액에 존재하는 serine의 함량을 측정함으로써 간접적으로 CPP 생산을 평가하였다. CPP 생산 능력은 OPA방법으로 측정했을 때 E. faecalis A-2 균주가 1.244 mg/mL로 가장 많은 peptide를 생산 하였다. 본 실험에 사용된 유산균의 경우, 세포내 효소와 세포외 효소로 각각 나누어 proteolytic 활성을 평가한 결과 세포내 효소에 의한 proteolytic 활성은 E. faecalis A-6 균주가 가장 높은 것으로 나타났으며, 세포외 효소에 의한 proteolytic 활성은 L. plantarum A-14 균주에서 가장 높게 나타났다. 가용성 칼슘함량은 Leuconostoc mesenteroides A-1(11 mg/dL), E. durans A-16(10.481 mg/dL), 그리고 L. planatarum A-3(10.356 mg/dL) 균주의 경우에는 대조구보다 높은 유리 칼슘함량을 나타내었다. 따라서 이러한 유산균을 이용한다면 소장 내에서 칼슘 흡수를 극대화시킬수 있는 장점이 있어 이들 유산균을 이용한 고칼슘 제품 개발이 가능할 것이다.

• Nutrition Research and Practice
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• 제9권5호
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• pp.539-546
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• 2015

BACKGROUND/OBJECTIVES: Women's bone health status is closely related with environmental factors and lifestyle factors. The purpose of this study is to evaluate the dietary risks of osteoporosis and osteopenia for Korean postmenopausal women. SUBJECTS/METHODS: The data from 1,433 subjects from the 2010 KNHANES were used and divided into three groups: normal, osteopenia, and osteoporosis group using bone mineral density (BMD). Nutrient intakes and food intake frequency were evaluated. Logistic regression analysis was applied to determine the odds ratios for osteoporosis and osteopenia. RESULTS: The RNI percentage of each nutrient and food intake frequency from 12 food groups decreased as bone mineral density status deteriorated. Risk for osteoporosis of low calcium (Ca) intake, under the EAR, showed an odds ratio of 2.13(95% CI; 1.26-3.61, P < 0.05). Higher intake frequency showed preventive effect from osteoporosis compared to lower intake frequency in such food group as dairy products (ORs 0.40, CI 0.21-0.75), beans (ORs 0.49, CI 0.29-0.83), seaweeds (ORs 0.55, CI 0.32-0.94), fish (ORs 0.56, CI 0.32-0.98), and fruits (ORs 0.42, CI 0.23-0.79) after adjusting for age. CONCLUSION: To prevent osteoporosis in later life, sufficient Ca intake and more frequent intakes of foods containing Ca such as dairy products, beans, fish, seaweeds, and fruits, which help in Ca absorption, should be stressed for Korean postmenopausal women.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4158-4165
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• 2021

In this study, tissue equivalency (TE) of a newly developed epoxy-based phantom to 3-5 years child's tissue was investigated in paediatric energy range. Epoxy-based TE-phantoms were produced at different glandular/adipose (G/A) ratios of 17/83%, 31/69%, 36/64% and 10/90%. A procedure was developed in which specific amounts of boron, calcium, magnesium, sulphur compounds are mixed with epoxy resin, together with other minor substitutes. In paediatric energy range of 40-60 kV_p half-value layer (HVL) values were measured and then Hounsfield Units (HU) were determined from Computed Tomography(CT) scans taken in the X-ray energy range of 80-120kV_p. It is found that radiation absorption properties of these phantoms in terms of the measured HVL values related to linear attenuation coefficients (µ) are very well mimicking a 3 years child's soft tissue in case a ratio of 10/90%G/A. Additionally, the HU values of phantoms were determined from the CT scans. The HU = 47.8 ± 4.8 value was found for the epoxy-based phantom produced at a ratio of 10/90%G/A. The obtained HVL and HU values also support the suitability of the new epoxy based-phantom produced at a ratio of 10/90%G/A for a satisfactory mimicking a 3 years child's soft tissue by 5%. Thus they can have a potential use to perform the quality controls of medical X-ray systems and dose optimization studies.

• 자동차안전학회지
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• 제13권2호
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• pp.30-34
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• 2021

Electrical failures and reliability problems of electronic components by ionic migration between adjacent device terminals have become an issue in automotive electronics. Especially unlike galvanic corrosion, ionic migration is occurred at high temperature and high humidity under applied electric field condition. Until now, although extensive studies of the ionic migrations dealing with PCBs, electrodes, and solders were reported, there is no study on the effect of insulation polymers and metallic fillers for ionic migration. In this research, therefore, ionic migration induced by the types and contents of polymers and metallic fillers, and variety conditions of temperature, humidity, and applied voltage was studied in detail. Ester and amide types of liquid crystal polymer (LCP) and poly (phthalamide) (PPA) were used as base polymers, respectively and compounded with the metallic fillers of Copper iodide (CuI), Zinc stearate (Zn-st), or Calcium stearate (Ca-st) in various compositions. The compounding polymers were fabricated in IPC-B-24 of SIR test coupon according to ISO 9455-17 with Cu electrodes for ionic migration test. While there is no change in LCP-based samples, ionic migration in PPA compounding sample with a high water absorption property was accelerated in the presence of 0.25 wt% or above of CuI at the environmental conditions of 85℃, 85% RH and 48V. The dendritic short-circuit growth of Cu caused by ionic migration between the electrodes on the surface of compounded polymers was systematically observed and analyzed by using optical microscopy and SEM (EDX).

• Advances in concrete construction
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• 제12권6호
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• pp.479-490
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• 2021

Present research is mainly focused on, microstructural and durability analysis of Graphene Oxide (GO) in Wollastonite (WO) induced cement mortar with silica fume. The study was conducted by evaluating the mechanical properties (compressive and flexural strength), durability properties (water absorption, sorptivity and sulphate resistance) and microstructural analysis by SEM. Cement mortar mix prepared by replacing 10% ordinary portland cement with SF was considered as the control mix. Wollastonite replacement level varied from 0 to 20% by weight of cement. The optimum replacement of wollastonite was found to be 15% and this was followed by four sets of mortar specimens with varying substitution levels of cementitious material with GO at dosage rates of 0.1%, 0.2%, 0.3% and 0.4% by weight. The results indicated that the addition of up to 15%WO and 0.3% GO improves the hydration process and increase the compressive strength and flexural strength of the mortar due to the pore volume reduction, thereby strengthening the mortar mix. The resistance to water penetration and sulphate attack of mortar mixes were generally improved with the dosage of GO in presence of 15% Wollastonite and 10% silica fume content in the mortar mix. Furthermore, FE-SEM test results showed that the WO influences the lattice framework of the cement hydration products increasing the bonding between silica fume particles and cement. The optimum mix containing 0.3% GO with 15% WO replacement exhibited extensive C-S-H formation along with a uniform densified structure indicating that calcium meta-silicate has filled the pores.