• Fibers and Polymers
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• 제3권2호
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• pp.55-59
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• 2002

The thermal reaction of acetoacetanilide in the presence of aniline or phenol yielded carbanilide in quantitative yields. This reaction was applied to the synthesis of polyurea. Bisacetoacetamides were prepared from diamines and diketene in DMF. They were thermally polymerized in the presence of phenol or a diamine (6FDA) to yield polyureas of low molecular weights. The polymers were soluble in DMSO and NMP. $^1{H-NMR}$ analysis showed that they had amino group terminated structures. Poly(urea-imide) was synthesized by the reaction of an oligourea diamine with pyromellitic dianhydride in NMP. The concentration of terminal amino groups was determined by an acid-base titration. The thermal property of poly(urea-imide) was evaluated by thermogravimetric analysis (TGA). Initial decompisition took place at 332-$350^{\circ}C$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.137-138
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• 2019

To overcome the limitation in relation to thermal insulator's selection and installation method that is suitable for exterior insulation and waterproof construction methods, a production basis of thermal insulators of which manufacturing knowhow is held by companies was ensured and future-oriented construction methods to adopt new materials were applied. Performance verification was conducted through performance and mock-up tests of thermal transmittance on the cross sections where the flexible insulators were applied based on the improved prototype and performance data were obtained. To overcome the biggest drawbacks (walking feeling and damage etc.) in the exterior insulation and waterproof construction method, inserting a protective layer between thermal insulator and water-proof layer was proposed, and polypropylene corrugated cardboards.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.177-178
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• 2018

In the case of conventional ultra-fast hardness membrane waterproofing material (polyurea, etc.), damage such as breakage or tearing occurred frequently at the time of cracking of the surface after waterproofing. In this study, it is suggested that a waterproof layer can not cope with the occurrence of cracks at the same time by applying the soft type waterproofing material of soft type at the lower part of the construction method (securing of elongation) To minimize the possibility of water resistance.

• 한국식품과학회지
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• 제32권5호
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• pp.1206-1212
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• 2000

가미육미지황탕이 BB rat에서 유발되는 당뇨병을 개선시킬 수 있는가를 알아보았다. BB rat은 태아시기부터 생후 120일까지 가미육미지황탕을 공급받았으며 생후 21일된 BB rat 60마리(수놈 30마리, 암놈 30마리)를 무처치군인 BBDP군과 가미육미지황탕을 투여한 군인 BBDP-GY군으로 임의로 배치하여 생후 120일까지 사육하였다. BBDP-GY군의 쥐들에게는 가미육미지황탕을 16mL/㎏ B.W./day 분량으로 물에 섞어 주었다. 가미육미지황탕의 항당뇨 효과는 다뇨, 다음, 고혈당 및 체중감소와 같은 임상적인 요소들에 의하여 조사되었다. 그 결과 가미육미지황탕은 당뇨병의 발병시기를 지연시켰을 뿐만 아니라 당뇨병의 발병율도 현저하게 감소시켰다. 그러나 일단 발병이 되고 나서는 당뇨병의 진전을 지연시키거나 치유하는 효과가 없는 것으로 나타났다. 당뇨의 발병과 동시에 체중의 현저한 감소 및 물 소모량, 배뇨량 그리고 혈당에 있어 현저한 증가가 나타났고 당뇨의 발병이 있기 전에는 체중에 있어서 발병 2-4일전에 체중의 증가가 거의 없거나 또는 약간 있을 뿐 다른 항목들에서는 발병을 알리는 어떤 변화도 나타나지 않았다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.151-152
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• 2015

Concrete parking slab is often deteriorated severely after winter season because of concrete's freezing and thawing phenomenon. In this study, some methods to improve resistance against freezing-thawing is experimentally tested.: 1) concrete strength, 2) air content in concrete, 3) saw-cut effect and finish material. After experiment, in case of no finishes, 24MPa concrete with 4% air content is tested best result in terms of relative elastics modulus among testes ones. In case of concrete with finishes, all specimens are improved regardless of finishes compared to concrete with no finishes. Improvement degree compared to no finish is as follows : Polyurea > Resin-mortar > hardener and the number of improvement degree is 5, 4, 2% respectively. Further work is required considering construction site condition such as gaining water on surface and remicon in order to reflect site condition.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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• pp.36-40
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• 2007

Inorganic layers, such as SiOxNy and SiOx deposited using plasma sublimation method, were tested as passivation layer for organic thin-film-transistors (OTFTs). OTFTs with bottom-gate and bottom-contact structure were fabricated using pentacene as organic semiconductor and an organic gate insulator. SiOxNy layer gave little change in characteristics of OTFTs, but SiOx layer degraded the performance of OTFTs severely. Inferior barrier properties related to its lower film density, higher water vapor transmission rate (WVTR) and damage due to process environment of oxygen of SiOx film could explain these results. Polyurea and polyvinyl acetates (PVA) were tested as organic passivation layers also. PVA showed good properties as a buffer layer to reduce the damage come from the vacuum deposition process of upper passivation layers. From these results, a multilayer structure with upper SiOxNy film and lower PVA film is expected to be a superior passivation layer for OTFTs.

• 상하수도학회지
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• 제30권6호
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• pp.725-736
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• 2016

There is a growing concern on the improvement of water distribution pipeline for multi-regional water supply system in Korea along with its aging infrastructure. Rehabilitation of large diameter pipeline is more efficient in cost and time compared to replacement with trenching. The procedure for rehabilitation are diagnosis, cleaning, spraying coating material, and final inspection. The internal state of pipeline was carefully diagnosed and got C grade, which required rehabilitation. We found that 17,274,787,000 Korean won could be saved after pipe surface coating because of increased C coefficient of Hazen-Williams equation. Optimal coating material was D polyurea. We also found optimal distance between spraying nozzle and pipe wall to be 70 - 80 cm, which were critical factors for coating quality. This study also illustrated the time for spray drying to be more than 30 min. These results could be used in the quality control process during rehabilitation of aged pipelines.

• 한국건축시공학회지
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• 제15권6호
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• pp.579-587
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• 2015

자기치유성능을 가지고 있는 자기치유제를 함유하고 있는 마이크로 캡슐을 콘크리트 표면의 고분자 매트릭스층에 적용하였다. 메타크릴레이트를 코어물질로 하고 폴리 우레아포름알데히드를 캡슐막 구성물질로 하는 미세캡슐을 고분자 매트릭스 안에 첨가하여 콘크리트 표면에 코팅하였다. 콘크리트 표면에 미세균열이 형성되고 전파될 때, 균열이 전파되는 위치에 있는 캡슐이 파괴되어 치유체가 균열면 사이로 흘러나오게 되고, 균열에 스며든 단량체가 햇빛에 의해 중합반응을 일으켜 균열이 자기치유 되는 현상을 고찰한다. 자기치유성능평가는 흡수성, 투수성 실험 및 광학현미경을 통한 관찰로 확인하였다. 결과적으로 제시된 자기치유시스템은 콘크리트 균열부의 부분적인 복원을 위해 사용할 수 있음을 확인하였다.

• 한국응용과학기술학회지
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• 제37권4호
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• pp.1034-1040
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• 2020

스테인레스 스틸에 대한 합성된 폴리우레탄-에폭시 수지의 기계적 특성은 SEM, FT-IR, 인장특성, 그리고 EIS에 의한 특정질량손실량, 입도분석 등에 의해 물성을 측정하였다. 친환경적인 NATM 도료에 관한 관심이 고조됨에 따라 스테인레스 등의 금속에 코팅하는 무용제 도료를 합성하였다. 폴리올, IPDI, 충진제, 실리콘 계면활성제, 촉매 등이 함유된 기존 중방식수지보다 폴리올, MDI, 충진제, 실리콘 계면활성제, 촉매가 함유되어 합성된 중방식수지의 도료가 온도변화에 따른 인장강도가 증가하였고, 전해성이 높은 용액 속에서 저헝력이 크게 측정되었으며, 내구력과 강도가 양호하였다. 견고한 NATM 수지의 기계적 특성은 가교와 부식환경의 차단력이 증가함에 따라 강도가 증가하였다. 결론적으로 중방식의 가교된 미세조직은 방청코팅이 어려운 스테인레스 스틸 같은 금속물질 코팅에도 좋은 실험결과를 보여주었다.

• 대한한방내과학회지
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• 제28권3호
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• pp.544-559
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• 2007

Objectives : This study was designed to evaluate the anti-diabetes and vasoelasticity effects of Mori Folium and Aurantii Fructus in streptozotocin-induced type II diabetes mellitus model. Methods : The anti-diabetic effect of Mori Folium and Aurantii Fructus on rats induced with diabetes by streptozotocin was investigated through analyses of changes in body weight, blood glucose, urine volume of rats, viability of human umbilical vein endothelial cells(HUVECs), and elasticity of descending thoracic aorta in rats. The subjects in this study were divided into four groups(n=15): a normal group without any treatment (Con), a normal group with Mori Folium and Aurantii Fructus treatment(Con+P), a diabetes group induced by streptozotocin(STZ), and a Mori Folium and Aurantii Fructus treatment group under diabetes induced by streptozotocin(STZ+P). Rats were administered streptozotocin to induce diabetes. Results : The study showed that Mori Folium and Aurantii Fructus significantly reduced highly increased blood glucose levels(p<0.01) and prevented the diabetic rats from weight loss(p<0.01) and polyurea(p<0.05), Mori Folium and Aurantii Fructus also recovered decreased viability of HUVECs(p<0.01) and damaged elasticity of aorta induced by the streptozotocin (p<0.01). Conclusions: It was concluded from the results that Mori Folium and Aurantii Fructus have a distinct anti-diabetes effect and they also prevent damage of blood vessel induced by diabetes. resulting in prevention of cardiovascular diseases ascribed to diabetes.