• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.54-63
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• 2012

The purpose of this study is to examine the potential for reducing the environmental load and $CO_2$ gas when cement is produced by using cement substitutes. These substitutes consisted of blast furnace slag, red mud and silica fume, which were industrial by-products. The most optimum mix was derived when alkali accelerator was added to low carbon inorganic composite mixed with industrial by-product at room temperature. It is determined that hardened properties and the results of compressive strength tests changed based on CaO content, Si/Al, the mixing ratio and the amount of alkali accelerator, curing conditions and W/B. The results of test analysis suggest that the optimum mix of low carbon inorganic composite is CaO content 30%, Si/Al 4, the mixed ratio of alkali accelerator $(NaOH:Na_2SiO_3)$ 50g:50g, the amount of alkali accelerator 100g and W/B 31%. In addition, if contraction is complemented, low carbon inorganic composite with superior performance could be developed.

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.667-676
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• 2007

As the 21st century began, cement and concrete that are representatives of modem building materials became a major factor in global warming, air pollution and environmental pollution. Also, the problems that are generated while pursuing high performance and high strength became social issues. Therefore, it has become urgent to prepare counter plans. This study has aimed at the recycling of sewage sludge ash and developing it as a new concept in building material which serves the environmental considerations for long-lasting developmental purpose. Also, the study aimed to find a substitute for scarce natural resources and to secure high techniques for waste recycling. The purpose of this study was also to solve fundamentally secondary environmental pollution. The results revealed that the chemical components of sewage sludge ash are mainly $SiO_2\;and\;Al_2O_3$ which are similar to the components of pozzolan. Also, it was identified that sewage sludge ash can be utilized as a hardened specimen with an alkali activated pozzolan reaction. Considering the possibility of appropriate strength development and the advantage of drying shrinkage, compared with that of cement, it was believed that sewage sludge ash can demonstrate a function as a substitute for cement given.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.341-348
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• 2017

The performance degradation of concrete pavement by winter deicer is very serious in Korea, and its maintenance and rehabilitation brings a high expense. Therefore, a suitable method for rehabilitation of such concrete pavement and repair material of proper performance are required. In this study, the properties of compressive strength, ability to resist chloride ion penetration, and properties of dry shrinkage of magnesium phosphate ceramics were assessed to evaluate its applicability as a repair material for concrete pavement in Korea. As a result, the mortar flow showed a normal level of 190 mm, but the viscosity was high and the self-flow ability was poor. The setting time was 12 minutes, leading very rapid-hardening, and thus a prompt work was required. The compressive strength of mortar was 38.4MPa in 2 hours, 73.8MPa in 24 hours, and 111.0MPa in 28 days, showing a significant level. As a result of the test to chloride ion penetration resistance, mortar showed 143 Coulombs, and concrete showed 172.6 Coulombs, which fell under very low level. The drying shrinkage of MPC concrete in 40 days was below $60{\times}10-6$, and comparing with normal cement concrete, it showed the level below 1/10 of other concrete to secure an excellent volume stability. As above, magnesium phosphate ceramics has excellent strength performance, chloride ion penetration resistance, and volume stability, and this in the future shall be used in construction under the consideration of working time or workability, requiring further improvement for such performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.59-67
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• 2017

The objective of this paper is to investigate experimentally the effect of replacement of recycled coarse aggregates with 5~13mm in size on a field applicability of concretes through Mock-up test. Seven different mock-up specimens were prepared with the size of $1200{\times}800{\times}800mm$ simulating column and wall. For the concrete mixtures, 24MPa, 27MPa and 40MPa of nominal strength were adopted with 30% and 70%(only for 24MPa) of 5~13mm recycled coarse aggregate (RCA) replacement and without 5~13mm RCA(Plain). For test items, slump, slump flow, compressive strength with different curing conditions, core drilling, rebound numbers and drying shrinkage were measured. Test results indicated that 30% of 5~13 mm RCA replacement resulted in increase in slump, slump flow and resistance against segregation, while air contents decreased compared to those of plain mixture. Compressive strength of concrete with 30% of 5~13mm RCA was shown to be higher than that of plain mixture due to optimum packing effect associated with presence of well graded aggregates. Rebound number of the mock-up specimen with 30% of 5~13mm RCA had lower fluctuation according to hitting location than that of plain mock-up specimen. It is believed from the results of the study that replacement of 30% of 5~13mm RCA brings desirable improvement in various aspect of concrete performance due to associated dense packing effect.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.93-100
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• 2020

3D printing technology enables proper objects to be made through an additive manufacturing method, but resulting in dimension deviation of the product due to contraction phenomenon as cooling melted filament resin injected from high-temperature use environment. In this research, we studied on acrylic adhesives for 3D printer build sheet in order to fabricate high-quality products with a precise shape and to well-mount without distortion. The solvent-free UV-curable acrylic adhesive formulation was designed by adding 4-acryloylmorpholine (ACMO) with high adhesion, toughness, glass transition temperature so that adhesion properties are stable at high temperature and products are easily mounted/detached from the adhesives. The designed formulation was polymerized through two-steps using post-addition of monomers. Using this, the acrylic adhesive was coated to make a film and then analyzed using various experimental techniques. As a result, the fabricated adhesive exhibited high glass transition temperature and there was little gap in peel strength before and after thermal treatment. Moreover, it was confirmed by rheological analysis that this adhesive can provide great bonding/debonding ability without distortion. We demonstrated the fabrication of a rectangular product using a 3D printing method using our acrylic adhesive as a build sheet. Mounting ability and workability were satisfactory and dimension deviation of the product was tiny. Because the product is easily detachable from the acrylic adhesive developed here than conventional build sheets, it is expected that this will provide work convenience to users who use the 3D printer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.829-836
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• 1995

This study was performed to evaluate the relationship between dietary, blood and urinary levels of lead and blood pressure and serum lipids in 30 healthy adult living in rural area of Korea. Analysis for the nutritional status of subjects were performed by 3-day dietary intake record, duplicated diet collection, 24-hour urine collection, and venous blood sampling before anthropometry. The mean daily intakes of lead estimated for 3 days was $120.1{\pm}22.0\mu\textrm{g}$. The blood levels and 24-hour urinary excretion of lead were $10.8{\pm}3.6\mu\textrm{g}/dl\;and\;36.5{\pm}9.5\mu\textrm{g}$, respectively. The systolic and diastolic blood pressure were $113.0{\pm}16.9mmHg\;and\;76.7{\pm}12.1\;mmHg$. The serum levels of total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol and ${\beta}-lipoprotein$ were $158.8{\pm}32.9mg/dl,\;104.6{\pm}48.8mg/dl,\;45.7{\pm}9.9mg/dl,\;92.2{\pm}28.5mg/dl\;and\;426.4{\pm}141.5mg/dl$, respectively. There was no significance in the relation between lead and blood pressure. In the relation between lead and serum lipids, it showed negative correlation with lead intake and HDL-choleterol at the level of significance of p<0.01. But there was no significance in the relation between lead and serum levels of otehr lipids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.464-468
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• 2003

The antihypertensive and cholesterol- lowering effects of Monascus koji (M. koji) prepared with Monascus ruber IFO32318 were examined in spontaneously hypertensive rats (SHR). Control was fed a normal diet and groups I, II or III were fed diets containing 0.03%, 0.1% or 0.3% M. koji for 8 weeks, respectively. After 8 weeks, all animals were fed normal diets in the following 2 weeks. The blood pressure of rats fed M. koji added diets were significantly attenuated as compared with control and the diet containing high concentration of M. koji had a tendency of stronger antihypertensive effect. These differences lasted throughout the experimental period when they were fed experimental diet. For 2 weeks after the 8 weeks of experimental diet all groups were fed the same normal diet and the differences of blood pressure caused by M. koji disappeared. In rats fed the M. koji added diet, the serum total cholesterol (TC), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C) were not differed compared with control, but VLDL cholesterol (VLDL-C) was significantly lowered. M koji also significantly decreased serum risk factors, both TC/HDL-C ratio and non HDL-C/HDL-C ratio. Consequently, it is suggested that M. koji may play an important role to attenuate hypertension and to improve serum lipid Profiles.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.273-284
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• 2010

The purpose of this study was to investigate the effects of weight control program on dietary habits and blood composition in obese middle-aged women. The program consisted of nutrition education, physical exercise and nutrition counseling was conducted for 12 weeks. Participants of the preliminary study were 255 obese women, among which 82 women participated in the nutrition education program. We evaluated the anthropometry, blood lipid profiles, dietary habits of obese women before and after the nutrition education. Dietary habits of the subjects were significantly improved in regularity of having breakfast (p < .05), the frequency of eating snack after dinner (p < .001), eating out (p < .01) and the speed of meal (p < .05) after the program. There was significant decrease in total cholesterol, triglyceride, LDL-cholesterol and systolic pressure of the subjects after nutrition education. Changes of atherogenic index and diastolic pressure were not significant, but had a tendency to decrease. All of the anthropometric outcomes except lean body mass such as BMI, percent body fat, fat mass, and WHR were significantly decreased after weight control program. These findings show that weight control program including nutrition education and counseling can improve dietary habits and weight control pattern, and lead the authors to recommend that public health organizations and dietetic professionals should educate obese women on practical strategies for an effective weight management.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.80-80
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• 2001

제지 공정의 효율적인 운영을 위한 수단으로 보류 및 탈수성의 분석은 매우 중요한 작 업 이 다. 보류 및 탈수 특성 을 평 가하기 위 하여 SR(Shopper-Riegler), CSF(Canadian S Standard Freeness tester) 그리고 원형 수초지기 등의 비난류 상태의 자연탈수 특성 평가 장치와 동적 조건의 감압식 탈수성 분석기 등이 사용되고 있다. 하지만 이것들은 제지 공정 에 보다 더 근접한 탈수 및 보류 특성을 평가하기에는 부족한 점이 있다. 특히 wet-end 첨 가제들의 효능을 보다 정확히 분석하는 것이 불가능하다. 이런 이유로 난류 발생과 감압 탈 수 둥을 유도한 탈수 특성 평가 장치 개발의 필요성이 커지고 있다. R RDA - HSF(Retention Drainage Analyzer- Handsheet Former)는 지료조성, 감압탈수 및 습지의 성형이 자동화되어 보류도와 탈수성, 종이지합 및 강도를 종합 평가 할 수 있는 새 로운 실험실용 초지기이다. 보다 현장에 가까운 초지 조건을 구현하기 위해서 지료의 농도 를 높이고 진공 탈수를 실시함에 따라 기존의 탈수성 분석기나 보류도 측정기의 단점을 보 완하게 되 었다. 본 연 구에 서 는 Canadian Standard Freeness test와 Dynamic Drainage Jar test 및 원 형 수초지기를 활용한 기존의 탈수성, 보류도 분석 결과와 RDA-HSF를 비교하여, 자연 탈수를 이용하는 기존의 탈수 및 보류 설비에 비해 현장 공정을 보다 현실적으로 재현할 수 있는 감압 탈수 초지 설비로서 RDA-HSF의 활용 가능성을 분석하였다. RDA-HSF를 활용한 실험실적 분석을 통해 현장의 상황올 유사하게 재현함에 따라 공정 운영 인자의 변화에 따른 제품의 품질 및 생산효율을 예측할 수 있게 된 바, 보다 효율적 인 공정 관리가 가능할 것으로 기대된다. 안료 입자의 경우 피인쇄체의 표면 공극을 채우고, 비히클의 경우 미세한 공극속으로 침투되어 경화됨으로써 피인쇄체가 지니고 있는 공극량을 감소시커 게 될 것이다. 그리고 피인쇄체의 각종 형태의 공극으로 침투된 잉크의 양에 반비례적으로 피인쇄체의 표변에 잉크가 잔류하게 될 것이다. 따라서 본 연구에서는 여러가지 안료를 사용하여 각각 다른 공극 특성을 지니는 도공지를 제조한 후 이들이 가지는 공극 특성과 잉크의 잔류 거동에 대해 고찰해 보고자 하였다.여 표면 유효층 일부만 오버레이시키며I 주조 및 단조가 불가능한 재료까지도 표면부에 오버레이 시킴으로 서 부품 및 설비의 제조에 있어 재료비의 절감과 제품의 수명이 획기적으로 개선될 수 있다. 그리고 최근에는 도금 빛 용사 둥과 같은 표면처리를 할 경우임의 소재 표면에 도금 및 용 사에 용이한 재료를 오버레이용접시킨 후 표면처리를 함으로써 보다 고품질의 표면층을 얻기위한 시도가 이루어지고 있다. 따라서 국내, 외의 오버레이 용접기술의 적용현황 및 대표적인 적용사례, 오버레이 용접기술 및 용접재료의 개발현황 둥을 중심으로 살펴봄으로서 아직 국내에서는 널리 알려지지 않은 본 기 술의 활용을 넓이고자 한다. within minimum time from beginning of the shutdown.및 12.36%, $101{\sim}200$일의 경우 12.78% 및 12.44%, 201일 이상의 경우 13.17% 및 11.30%로 201일 이상의 유기의 경우에만 대조구와 삭제 구간에 유의적인(p<0.05) 차이를 나타내었다.는 담수(淡水)에서 10%o의 해수(海水)로 이주된지 14일(日) 이후에 신장(腎臟)에서 수축된 것으로 나타났다. 30%o의 해수(海水)에 적응(適應)된 틸라피아의 평균 신사구체(腎絲球體)의 면적은 담수(淡水)에 적응된 개체의 면적보다 유의성있게 나타났다. 해수(海水)에 적응(適應

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.1049-1053
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• 2009

This study was carried out to investigate the effects of Eucommia ulmoides Oliver (Du-Zhong) as a main ingredient in a mixture of various medicinal herbal extracts on blood pressure, serum lipid concentrations, and hematological variables in hypertensive patients. After 4 weeks on drinking the mixed medicinal herbal teas, systolic blood pressure remarkably decreased from 167.14 to 134.86 mmHg and diastolic blood pressure decreased from 100.00 to 87.10 mmHg. In terms of serum lipid profiles, there were no differences in total-cholesterol, HDL-cholesterol, LDL-cholesterol level, and atherogenic index, However, the level of triglycerol was significantly reduced from 237.1 before the experiment to 145.00 mg/dL after 4 weeks on drinking the mixed medicinal herbal teas. Serum triglyceride were remarkably reduced from 237.1 to 145.00 mg/dL in the hypertensive patients who had taken the combined medicinal herbal extracts. Compared with data obtained from the patients before the experiment, there were no differences in hematological variables (RBC, WBC, hematocrit, hemoglobin, platlets and homocysteine) after the 4 weeks experiments, but mean corpuscular hemoglobin concentration was significantly increased by 2.70% (p<0.05) in the blood samples. Based on these findings, it can be presumed that the examined mixed medicinal herbal tea may be effective in lowering blood pressure and in increasing mean corpuscular hemoglobin concentration due to reduced serum triglyceride levels in hypertension patients.