조강시멘트를 사용한 라텍스개질 콘크리트의 보수재료 개발

윤경구,김동호,최성용,최판길 강원대학교 부설 석재복합신소재 제품연구센터 2004 석재연 논문집 Vol.9 No.-

The purpose of this research was to develop an available repair material to solve the problem such as coherence, construction period and economic performance that the repair material of existing water-construction have. The latex was good at coherence and resistance of permeability and the high-early cement shorten construction period through the early strength development. Therefore, in this study, we tried to develop the High-Early Strength Latex Modified Concrete(below ; HESLMC) combining these two characteristics. First, to find the optimum mixtures according to the construction criteria, slump condition, the maximum size of coarse aggregate and the antifoam agent adjusting air-content were selected as the major variables. The unit weight of cement and percentage of fine aggregate were fixed by 400 kg and 50 %, respectively. The suitable content of latex was 15% with considering the situation of inside and outside of the country. Second, the strength tests in order to estimate the mechanical characteristics were carried out and the permeability test of chloride ion and scaling test were carried out to estimate of durability of HESLMC, respectively. In all experimental variables, the results of strength test showed that the compressive strengths and flexural strengths, at 3 days after placement, were more than 21 MPa and 4.5 MPa, respectively. Especially, the resistance of permeability was excellent when compared to that of High Early-Strength Concrete(below ; HESC). 본 연구의 목적은 기존 콘크리트 수리구조물 보수재료가 갖는 부착성, 시공기간 및 경제성의 문제를 해결하기 위한 적절한 보수재료 개발에 있다. 따라서 본 논문에서는 부착성 및 장기공용성이 우수한 라텍스의 특성과 조기강도발현을 통해 공기단축이 가능한 조강시멘트의 특성이 결합된 조강형 라텍스개질 콘크리트를 개발하고자 하였다. 첫째로 HESLMC의 시공조건에 따른 최적배합도출을 위하여 슬럼프조건, 굵은 골재 최대치수 및 소포제량을 주 변수로 설정하였다. 국내외 여건을 고려하여 단위 시멘트량과 잔골재율은 각각 400 kg, 50 %로 적정 라텍스 함량은 15 %로 하였다. 둘째로 역학적 특성 파악을 위한 강도실험과 내구성 특성을 파악하기 위한 투수저항성 실험과 표면박리저항성 실험을 실시하였다. 강도측정결과는 모든 변수에 있어 재령 3일의 압축강도가 21 MPa, 휨강도가 4.5 MPa 넘어 초기강도를 만족하는 것으로 나타났다. 특히, 투수저항성은 HESC와 비교하여 상당히 우수하게 나타났다.

증기상 Beckmann 전이 반응에 대한 Aluminophosphate 분자체의 촉매 특성

윤영삼,박판욱,권성헌,김병주 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

Molecular sieves인 AIPO₄-5, SAPO-5 그리고 SAPO-11을 수열합성하여 제조한 다음 XRD, SEM, NH₃TPD와 IR을 통해 물리화확적 특성을 조사하였다. 증기상에서 cyclohexanone oxime의 Beckmann 전이 반응 결과는 oxime의 전화율과 Lactam의 수율에 있어서 SAPO-11가 반응성이 우수하였고, WHSV의 변화에 있어서는 AIPO₄-5와 SAPO-5 경우 WHSV가 증가할수록 전화율과 선택도는 감소하였지만 SAPO-11는 선택도가 증가함을 보였다. 본 대상 반응계인 Beckmann 전이 반응에서는 촉매의 기공 크기보다는 산성도에 더 큰 영향을 받음을 알수 있었다. AIPO₄-5, SAPO-5 AND SAPO-11 which are molecular sieves were synthesized by hydrothermal crystallization. The crystallinity of the prepared catalysts was confirmed by XRD and SEM, and their acidic properties were examined by TPD of NH₃and IR. Catalytic characteristics of the catalysts were tested by vapor phase Beckmann rearrangement of cyclohexanone oxime to caprolactam. The conversion of lactam and yield of lactam increased with acidity of the catalyst. Among the tested catalysts, SAPO-11 was excellent in Beckmann rearrangement reaction. AIPO₄-5 and SAPO-5 showed that conversion of oxime and selectivity of lactam decreased with the increase of WHSV but SAPO-11 showed different tendency in selectivity of lactam, or selectivity of lactam increased with the increase of WHSV. Beckmann rearrangement reaction was affected by acidity than pore size.

Random Amplified Polymorphic DNA Typing에 의한 동물과 사람 유래 Vancomycin 내성 장구균의 유전학적 비교

조윤상,이희수,김종만,류판동,박용호,유한상,이문한 한국수의공중보건학회 2003 예방수의학회지 Vol.27 No.1

It has been recently reported the possibility in the transfer of antimicrobial resistant to other animals and humans. In particular, the occurrence of vancomycin resistant enterococci (VRE), which have been known as a principal antimicrobial resistant bacteria in humans, has been increased as a pathogen of nosocomial infections. And then animal VRE were suspected as an origin of human VRE. In this work, we investigated the relatedness between VRE from animals and humans through random amplified polymorphic DNA (RAPD) typing. The genetic relatedness of vanA, vanB, vanC-1 and vanC-2 genotypes was examined by RAPD typing, respectively. van4 genotypes have not been shown high genetic relationship each other, containing VRE from humans (n = 8) and chickens (n = 5). In vanB genotypes from humans (n = 3), 2 isolates were made up one cluster, shown 77.8% homology. Chicken isolates of vanC-1 genotypes (n = 11) were constituted 2 clusters and the homology of 2 clusters was 81.8% and 80.0%, respectively. In case of vanC-2 genotypes (n = 19), 2 isolates from pigs have been shown 76.9% homology. But, between VRE from animals and humans, the isolates of high genetic relationship could not be found and RAPD typing was a useful epidemiological method that could be confirmed the genetic relationship among VRE.

동물과 사람유래 Vancomycin 내성 장구균의 항균제 감수성 비교

조윤상,이희수,김종만,류판동,박용호,유한상,이문한 한국수의공중보건학회 2003 예방수의학회지 Vol.27 No.1

It has been recently reported the possibility in the bansfer of antimicrobial resistance to other animals and humans. In particular, vancomycin resistant enterococci (VRE), which have been known as a principal antimicrobial resistant bacteria in humans, have been increased as a pathogen of nosocomial infections. And then animal VRE were suspected as an origin of human VRE. In this study, we isolated Enterococcus spp. from animals, identified by bio- chemical tests, examined for antimicrobial susceptibility, and then compared the antimicrobial susceptibility of VRE among each other as well as human VRE. Enterococcus iecium (29%) was predominant in Enterococcus species (n=122) isolated from animal feces in this study. E. hirae, E. iecalis, E. casseliflam and E. gallinarum were also isolated as rates of 24%, 21%, 16% and 7%, respectively. The resistance of enterococci to penicillin and tetracycline were 66% and 78%, respectively, and the susceptibility of them to chloramphenicol was 66%. Antimicrobial susceptibility test has shown that 91% of VRE from humans (n=11) was susceptible to chloramphenicol and all resistant to penicillin, rifampin and streptomycin. Seventy-five percentage of VRE from chickens (n = 12) was susceptible to rifampin and resistances of them to penicillin, tetracycline and sbeptomycin were 75%, 83%, and l00%, respectively. Therefore, we confirmed the difference of antimicrobial susceptibility from animals and humans, and the antimicrobial susceptibility test could be one of the simple and useful methods for the epidemiological survey of VRE.

LMC와 RSLMC의 열팽창 특성에 관한 연구

임홍범,최성용,최판길,윤경구 江原大學校 産業技術硏究所 2004 産業技術硏究 Vol.24 No.A

Latex modification of concrete provides the material with higher flexural strength, as well as high bond strength and reduced water permeability. However, If the thermal expansion properties of overlay concrete (latex-modified concretes) are big different from that of substrate (ordinary portland cement concrete), these would cause a big interfacial stresses and result in premature failure. Therefore, the purposes of this study were to investigate thermal expansion characteristics of latex-modified concrete with cement types. The result of thermal expansion showed the coefficient of thermal expansion of concretes increased with latex inclusion. The coefficient of thermal expansion of RSLMC was a little smaller than that of LMC, which might be due to the finer cement grain, compacter internal, and stiffer properties of concrete. However, the coefficients of LMC and RSLMC were quite similar to that of ordinary cement concrete. Thus, this would not cause an interfacial stresses and will enable to ensure long-term performance of concrete bridge deck overlays.

외국인 대학원 유학생의 학습 과정 대한 셀프 내러티브

리윈윈(Yun-Yun Li),푸신지(Xin-Ji Fu),천판판(Pan-Pan Chen) 한국교육과정개발원 2023 한국교육과정개발연구 Vol.2 No.1

셀프 내러티브 탐구를 통하여 더 많은 유학생들이 한국 생활에 적응할 수 있도록 도움을 주고자 하는 것이 본 연구의 목적이다. 언어와 문화적 어려움, 글의 작성에 대한 어려움을 말하였지만 이러한 어려움들을 잘 극복하는 일은 내가 누구인가, 나는 왜 학습을 하는가, 공부의 목적을 어디에 둘 것인가 하는 문제 등을 지속적으로 성찰하다 보면 해결은 잘 될 것으로 본다.더 많은 유학생들이 한국에 와서 꿈과 자존감을 실현할 수 있도록 인사이트를 제공할 수 있기를 바란다. The purpose of this study is to help more international students adapt to Korean life through self-narrative exploration. Language and cultural difficulties, and difficulties in writing, but I think the solution will be successful if I continue to reflect on the problems of who I am, why I learn, and where to put the purpose of studying. It is hoped that more international students can come to Korea and provide insights to realize their dreams and self-esteem.

Cosmic voids in Sloan Digital Sky Survey Data Release 7

Pan, Danny C.,Vogeley, Michael S.,Hoyle, Fiona,Choi, Yun‐,Young,Park, Changbom Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.421 No.2

<P><B>ABSTRACT</B></P><P>We study the distribution of cosmic voids and void galaxies using Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Using the VoidFinder algorithm based on the original VoidFinder method devised by El‐Ad & Piran and implemented by Hoyle & Vogeley, we identify 1054 statistically significant voids in the Northern galactic hemisphere with radii > 10 <I>h</I><SUP>−1</SUP> Mpc. The filling factor of voids in the sample volume is 62 per cent. The largest void is just over 30 <I>h</I><SUP>−1</SUP> Mpc in effective radius. The median effective radius is 17 <I>h</I><SUP>−1</SUP> Mpc. The voids are found to be significantly underdense, with density contrast δ < − 0.85 at the edges of the voids. The radial‐density profiles of these voids are similar to predictions of dynamically distinct underdensities in gravitational theory. We find 8046 galaxies brighter than <I>M<SUB>r</SUB></I>=− 20.09 within the voids, accounting for 7 per cent of the galaxies. We compare the results of VoidFinder on SDSS DR7 to mock catalogues generated from a smoothed particle hydrodynamics (SPH) halo model simulation as well as other Λ cold dark matter (ΛCDM) simulations and find similar void fractions and void sizes in the data and simulations. This catalogue is made publicly available at http://www.physics.drexel.edu/~pan/VoidCatalog for download.</P>

Suppression of SPARC Ameliorates Ovalbumin-induced Airway Remodeling via TGFβ1/Smad2 in Chronic Asthma

Pan Yun,Zhang Dong,Zhang Jintao,Liu Xiaofei,Xu Jiawei,Zeng Rong,Cui Wenjing,Liu Tian,Wang Junfei,Dong Liang 대한천식알레르기학회 2024 Allergy, Asthma & Immunology Research Vol.16 No.1

Purpose: Airway remodeling is a critical feature of asthma. Secreted protein acidic and rich in cysteine (SPARC), which plays a cardinal role in regulating cell-matrix interactions, has been implicated in various fibrotic diseases. However, the effect of SPARC in asthma remains unknown. Methods: We studied the expression of SPARC in human bronchial epithelial cells and serum of asthmatics as well as in the lung tissues of chronic asthma mice. The role of SPARC was examined by using a Lentivirus-mediated SPARC knockdown method in the ovalbumin (OVA)-induced asthma mice. The biological processes regulated by SPARC were identified using RNA sequencing. The function of SPARC in the remodeling process induced by transforming growth factor β1 (TGFβ1) was conducted by using SPARC small interfering RNA (siRNA) or recombinant human SPARC protein in 16HBE cells. Results: We observed that SPARC was up-regulated in human bronchial epithelia of asthmatics and the asthmatic mice. The levels of serum SPARC in asthmatics were also elevated and negatively correlated with the forced expiratory volume in one second (FEV1) to forced vital capacity ratio (FVC) (r = −0.485, P < 0.01) and FEV1 (%predicted) (r = −0.425, P = 0.001). In the chronic asthmatic mice, Lentivirus-mediated SPARC knockdown significantly decreased airway remodeling and airway hyper-responsiveness. According to gene set enrichment analysis, negatively enriched pathways found in the OVA + short hairpin-SPARC group included ECM organization and collagen formation. In the lung function studies, knockdown of SPARC by siRNA reduced the expression of remodeling-associated biomarkers, cell migration, and contraction by blocking the TGFβ1/Smad2 pathway. Addition of human recombinant SPARC protein promoted the TGFβ1-induced remodeling process, cell migration, and contraction in 16HBE cells via the TGFβ1/Smad2 pathway. Conclusions: Our studies provided evidence for the involvement of SPARC in the airway remodeling of asthma via the TGFβ1/Smad2 pathway.

In situ Synthesis, Crystal Structure, XPS and Fluorescent Property of a Novel Two-Dimensional Binuclear Copper(I) Tetrazole Complex

Yun-Zhi Tang,Jun Huang,Man Zhou,Yun-Pan Deng,Qing Xu,He-Rui Wen 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

In situ Synthesis, Crystal Structure, XPS and Fluorescent Property of a Novel Two-Dimensional Binuclear Copper(I) Tetrazole Complex

Tang, Yun-Zhi,Huang, Jun,Zhou, Man,Deng, Yun-Pan,Xu, Qing,Wen, He-Rui Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1