• Title/Summary/Keyword: 경화 반응

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Therapeutic Effect of Plasmapheresis in Relapsed Focal Segmental Glomerulosclerosis after Steroid Pulse Therapy (스테로이드 충격요법 후 재발된 국소성 분절성 사구체 경화증에서 혈장반출법의 치료 효과)

  • Kim Lan;Kim Eun-Mi
    • Childhood Kidney Diseases
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    • v.7 no.1
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    • pp.1-8
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    • 2003
  • Purpose : Focal segmental glomerulosclerosis(FSGS) is known to have a poor prognosis and a poor response to treatment. We performed a combination therapy of plasmapheresis, steroid pulse and immunoglobulin in 4 patients with relapsed steroid dependent(SD) or steroid resistant(SR) FSGS after steroid pulse therapy. Materials and Methods : 8 cycles of plasmapheresis were performed in 4 patients with biopsy proven FSGS who had relapsed after steroid pulse therapy from March 1988 to July 2002. Clinical findings and treatment courses were reviewed retrospectively. Results : Among the 4 patients, there were 3 males and 1 female. After 8 cycles of plasmapheresis, clinical remissions were obtained. Two of the four patients had two relapses and received 2 more cycles of plasmapheresis which resulted in remissions. One of these patients had two further relapses and was treated with oral steroid resulting in clinical remission. Three patients have maintained normal serum creatinine level and glomerular filtration rates during the follow-up period of 10 years, and the other 1 patient for 5 months. Conclusion : A combination therapy of plasmapheresis, steroid pulse and immunoglobulin led to a complete remission in patients with FSGS who were SD or SR and was effective in maintaining normal renal function.

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Application of UV Curable Coating for the Surface Protection of Polymeric Materials: PVC and Polystyrene (고분자 물질의 표면 보호를 위한 자외선 경화 도료의 응용)

  • Moon, Myung-Jun;Park, Jin-Hwan;Lee, Gun-Dae;Suh, Cha-Soo;Kim, Jong-Rae
    • Applied Chemistry for Engineering
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    • v.2 no.2
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    • pp.175-184
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    • 1991
  • Ultraviolet curable coatings are often used to protect the surface of polymer materials exposed to the ultraviolet radiation. However, the adhesion of epoxy acrylate on poly(vinyl chloride) and the UV curable coating on polystyren are poor. The objective of this work was to improve the adhesion of coating according to various formulations of the reactive diluents and finishing methods using the photografting of multifunctional acrylate and the surface activation on polymer surface impregnated a phtoinitiator. The addition of Tripropylene glycole diacrlate in the formulation of coating results in the improvement of adhesion of coating due to the flexibility. But the increase of the crosslinking density which results from the oxidation of surface during the exposure of UV radiation caused the loss of adhesion of coating exept the photografting method. In the trimethylolpropane triacrylate the improvement of adhesion are considerable due to the chemical bond between multifundtional acrylate and surface. From this work we expect to achieve the varity and functionality in the formulation of coating according to the photografting and surface activating of polymer.

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Optimized Mixing Design of Lightweight Aerated Concrete by Response Surface Analysis (반응표면분석법에 따른 경량기포콘크리트 최적배합 도출에 관한 연구)

  • Lee, Sang-An;Jung, Chan-Woo;Kim, Wha-Jung;Ahn, Jung-Hyun
    • Journal of the Korea Concrete Institute
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    • v.21 no.6
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    • pp.745-752
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    • 2009
  • This paper presents the optimized mixing design of lightweight aerated concrete using hydrogen peroxide. Design of experiments in order to the optimized mixing design was applied and commercial program (MINITAB) was used. Statistical analysis was used to Box-Behnken (B-B) method in response surface analysis. The influencing factors of experimental are unit cement content, water ratio and hydrogen peroxide ratio. According to the analysis of variance, at the hardened state, water ratio and hydrogen peroxide ratio affects on dried density, compressive strength and bending strength of lightweight aerated concrete, but unit cement content affects on only dried density. In the results of response surface analysis, to obtain goal performance, the optimized mixing design for lightweight aerated concrete using hydrogen peroxide were unit cement content of 800 kg/$m^3$, water ratio of 44.33% and hydrogen peroxide ratio of 10%.

A Study on the Reactivity, Performance of 4HBA Modified High Solid Acrylic Polyurethane Paint (4HBA 변성 하이솔리드 아크릴 우레탄 도료의 반응성 및 물성 연구)

  • Seo, Seok-Hwan;Suh, Cha-Soo;Park, Jin-Hwan
    • Applied Chemistry for Engineering
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    • v.20 no.1
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    • pp.52-61
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    • 2009
  • In this study, TAPEH (t-amyl peroxy 2-ethyl hexanoate) was selected for the reaction initiator which is a core factor for developing acrylic polyol binder. Tone M100 (caprolactone acrylate), 4HBA (4-hydroxy butyl acrylate), and 2HEMA (2-hydroxy ethyl methacrylate) were used for hydroxy-monomers. To check the applicability of raw materials mentioned above into the binders of 2 components acrylic polyurethane paint and reduce the VOC, the reactivity and film performance by different kinds of aliphatic polyisocyanate hardeners which are already generalized were reviewed. As the Tin-based catalyst has been regulated, the comparison test of reactivity and performance between the conventional catalyst and non-toxic metal catalyst recommended as the alternative was conducted as well. As a result, we were able to obtain the basic data which are necessary for applying 2 components high solid polyurethane paint and also reached a conclusion that it can be applied for developing new paints in terms of high performance, workability and environmental care.

Integrated Optical Wave Plates Fabricated by Incorporating Reactive Mesogen in Polymer Waveguide (반응성 메조겐을 이용한 폴리머 광도파로 편광 변환기)

  • Do, Hyun-Soo;Chu, Woo-Sung;Oh, Min-Cheol
    • Korean Journal of Optics and Photonics
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    • v.22 no.5
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    • pp.219-222
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    • 2011
  • Integrated optical waveguide polarization converters are among the essential components for constructing various functional optical integrated circuits. The RM materials have been widely used in liquid crystal displays for fabricating waveplates. In this work, the polarization converters are fabricated by using a solution of Reactive Mesogen(RM) dissolved in liquid crystal(LC). In the middle of the polymer waveguide, a groove is defined by an oxygen plasma etching in a direction perpendicular to the optical waveguide. The solution of RM-LC is inserted to fill up the groove, and then liquid crystal is aligned in a certain direction by applying an electric field. After the alignment, RM materal is crosslinked by UV light so as to form a permanent waveplate. The phase retardation of the waveplate is determined by the width of the groove, and by the birefringence and the degree of alignment of the LC. Polarization conversion efficiency of 90% is obtained for the wavelength of 1550 nm.

Performance Evaluation of Admixture for Durability Improvement of Shielding Materials Used Waste Glass as Fine Aggregate (폐유리를 잔골재로 사용한 차폐채움재의 내구성 개선을 위한 혼화재료의 성능평가)

  • Hwang, Byoung-Il;Kim, Hyo-Jung;Song, Yong-Soon;Yi, Seong-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.2
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    • pp.20-27
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    • 2019
  • Compared to the development and manufacturing technology of electronic goods, the development of waste glass recycling technology is relatively insufficient, leading to the acceleration of waste of resources and environmental pollution. Although waste glass recycling technology is being actively developed overseas, waste glass recycling technology is insufficient in Korea, leading to the illegal dumping or burial of waste glass. Waste glass has been confirmed to have pozzolan reaction potential when having hydration reaction with cement. Waste glass is also reported to be effective in reducing bleeding and inhibiting the development of hydration heat by improving the physical properties of concrete and the rheology properties of fresh concrete. Therefore, this paper analyzed the strength characteristics and the effect of alkalic-silica reaction on the expansion of shielding concrete that used waste glass as fine aggregate. Where, suitable admixture materials were used as a measure to suppress the expansion.

Synthesis of Adhesion Promoters with Improved Compatibility and Properties of UV-Curable Adhesives Containing Adhesion Promoters (상용성이 개선된 접착 증진제의 합성 및 이를 함유한 자외선 경화형 접착제의 특성분석)

  • Park, Jung-Hyun;Won, Jonh-Woo;Kim, Ju-Yeol;Yoon, Yoo-Jung;Kwon, Oh-Hyeong;Hwang, Jin-Sang
    • Journal of Adhesion and Interface
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    • v.19 no.4
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    • pp.145-153
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    • 2018
  • In this study, adhesion promoters with acrylate and carboxylic acid moiety were synthesized from malenized polybutadiene and 2-hydroxyethyl acrylate for producing adhesive film with low water absorption and high adhesion. The surface properties, adhesion strength, mechanical properties and water absorption of adhesive films were characterized according to the amount of acrylate and carboxylic acid in the synthesized adhesion promoters. As the carboxylic acid in the adhesion promoters increased, the adhesion strength showed a tendency to increase and the mechanical properties also improved compared to the commercial adhesion promoter. The compatibility of adhesion promoters improved remarkably due to the presence of polybutadiene (hydrophobic nature), maleic anhydride (hydrophilic nature) and carboxylic acid (hydrophilic nature).

Synthesis and Properties of Photocrosslinkable Polymers Containing Rosin Moiety (2) (로진을 함유하는 광경화성 고분자의 합성과 특성(2))

  • 김우식;류상철;홍기헌;이동호;민경은
    • Polymer(Korea)
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    • v.24 no.6
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    • pp.757-762
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    • 2000
  • Vinylbenzyloxystyrylpyridine (VSP) as a photosensitive monomer was synthesized by the reaction of 4-hydroxystyrylpyrydine with 4-vinylbenzyl chloride. Photocrosslinkable polymers containing rosin moiety were then prepared by radically copolymerizing VSP with a methacrylic monomer having rosin moiety. In these copolymerizations, the VSP feed ratios of 5 to 20 mol% were used. The contents of VSP units in the copolymers were determined by UV spectroscopy to be 5.3 to 17.3 mol%. The numberaverage molecular weights of these polymers were in the range of 18000 to 28000 and the polydispersity indexes were about 1.8. The glass transition temperatures were about 15$0^{\circ}C$ and the initial decomposition temperatures were about 34$0^{\circ}C$. The polymers were relatively fast photocrosslinked and the photocrosslinking reaction could be traced by the UV spectroscopy and the residual yield method.

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Changes in Acid Graft Ratio and Al-CPP Lamination Peel Strength by Polyolefin Reaction Conditions (폴리올레핀의 반응 조건별 산변성도 변화 및 Al-CPP 라미네이션 박리강도 변화)

  • Jong Hyun Park;Hong Jun Chae
    • Journal of Adhesion and Interface
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    • v.25 no.1
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    • pp.152-156
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    • 2024
  • We conducted research on a two-component epoxy adhesive material based on acid graft polyolefin using maleic anhydride to address the lack of formability due to epoxy adhesives' hard segments. To understand the graft efficiency according to reaction conditions, we conducted studies based on polyolefin molecular weight, initiator half-life, and initiator concentration for each process. The maleic anhydride grafted polyolefin produced was used as an adhesive material for aluminum and CPP film lamination after mixing with epoxy hardener. The graft efficiency in the solution process was approximately 30% superior to that in the melt process, and an increase in graft ratio confirmed an increase in peel strength.

FeO, $TiH_2$, Carbon 원료분말을 이용한 Fe-TiC 나노 복합분말 제조 및 소결

  • An, Gi-Bong;Kim, Ji-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.10a
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    • pp.26-26
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    • 2011
  • Fe계 TiC 합금은 미량의 합금원소를 첨가시켜 경화능, 내식성, 내마모성 성질을 개선한 특수 공구용 재료로서 현재 절삭, 내마모성, 광산, 금형재료 등의 분야에 널리 사용되고 있다. 금속과 세라믹의 복합재료인 초경합금은 비열처리용 공구강으로 WC, TiC 등의 4, 5, 6족 금속탄화물에 Co, Ni, Fe등의 철족이 결합금속으로 소결한 복합재료로 WC-Co계 초경합금이 주종을 이루고 있으나, 전략 소재로서 고가인 Co 원료를 대체하기 위한 재료로서 초경재료의 고경도와 공구강의 경제성 및 가공성의 장점을 이용한 Fe-TiC계 초경합금의 연구가 다양하게 진행되고 있다. 본 연구에서는 Fe기지에 서브마이크론 크기의 미세한 TiC 입자가 균일하게 분산된 Fe-TiC 복합분말을 경제적으로 제조하기 위해 순수한 Fe, Ti 원료분말에 비해 단가가 낮고 미세 분쇄가 용이한 FeO, $TiH_2$ 분말을 고에너지 밀링 후 반응 열처리 시키는 유사 기계화학적 공정을 시도하였다. 조성비 Fe-30wt%TiC 복합분말을 제조하기위해 마이크론(micron) 크기의 FeO, $TiH_2$, C 분말을 사용하였고, 1단계로 FeO와 C을 고에너지 밀링으로 혼합 후 반응시켜 환원시키는 공정과 2단계로 이렇게 환원된 분말과 TiH2를 고에너지 밀링으로 다시 혼합, 분쇄한 후 반응열처리 하는 두 단계 공정을 사용하였다. FeO의 환원 단계에서는 $700{\sim}1,000^{\circ}C$ 온도 범위에서 1시간 유지하였고, 고에너지 밀링 시 밀링시간, 회전속도를 변수로 두고 실험하였다. 환원된 분말은 수평관상로를 이용해 아르곤분위기에서 $1,000{\sim}1300^{\circ}C$까지 1시간 유지하여 반응열처리시켜 Fe-TiC 복합분말을 제조하였다. 준비된 복합분말을 XRD와 FE-SEM, EDS, 입도분석기 (LPSA) 등을 이용해 분말의 형태와 특성, 상, 조성, 입도, 분산도 등을 조사하였다. 제조된 Fe-TiC 나노복합분말을 방전플라즈마소결(SPS) 과 상압소결 실험을 진행하였다. Fe-TiC 복합분말 제조공정의 첫 번째 단계인 FeO의 환원반응은 $800^{\circ}C$이상의 온도에서 Fe로 환원이 진행됨을 확인하였다. 두 번째 단계인 반응열처리공정에서는 $1,000^{\circ}C$ 이상에서 TiC가 형성됨을 XRD 상분석을 통해 확인할 수 있었고, $1,100^{\circ}C$ 이상의 온도에서 반응열처리를 했을 때 XRD 분석결과와 산소 조성 분석 결과로부터 반응의 완결성과 순도에서 최적 온도 조건임을 확인하였다. 온도를 $1,300^{\circ}C$로 증가시킬 경우 반응의 완결성에 큰 변화가 없는 반면 분말입자간의 목형성이 일어나 가소결 되는 것을 FE-SEM을 통해 관찰하였다. 또한 최적조건으로 제조된 Fe-TiC 복합분말의 입도분석과 FE-SEM/EDS 관찰/분석을 시행한 결과 평균 입도 0.6 ${\mu}m$의 미세한 Fe-TiC 복합분말 내에 Fe분말 주변과 내부에 나노크기의 TiC입자가 균일하게 분산되어 존재하는 것을 확인하였다.

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