朝鮮初期 性理學的 敎化의 政治的 意味에 대한 一考察

李承泰 韓國外國語大學校 大學院 1990 里門論叢 Vol.9 No.1

Ammonia effects on the electrochemical and structural properties for SOFC cathodes

이승태,김선아,이한솔,신지영,김건태 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Commercialization of solid oxide fuel cell (SOFC) requires excellent electrode materials and easy manufacturing. Among the various SOFC fabrication methods, infiltration technology is advantageous to enhance the electrochemical performance by forming nano-sized particles. However, it takes a long time to satisfy the efficient loading of the electrode materials. To resolve this problem, herein, a highly concentrated precursor solution is prepared by adding ammonia as a chelate agent. The addition of ammonia realizes a highly concentrated precursor solution by increasing the solubility of the precursor compared to the typical precursor solution using only citric acid. Furthermore, we investigated the effect of ammonia on the electrode microstructure, phase, electrochemical performance, and fabrication procedure.

산업부산물을 적용한 콘크리트 포장의 공학적 성능 평가

이승태,박광필 한국도로학회 2017 한국도로학회 학술대회 발표논문 초록집 Vol.2017 No.10

최근, 시멘트 사용량을 줄이고, 경제성을 확보하기 위하여 혼화재료를 적용한 콘크리트 포장에 대하여 많은 연구가 이루어지고 있다. 국내외적으로 콘크리트 포장용 결합재로써 활용되어지고 있는 혼화재료로써 고로슬래그, 플라이애시 등이 있으며, 이 중 고로슬래그는 냉각방법에 따라 급수로 냉각처리된 급냉슬래그와 공기 중에 냉각처리된 서냉슬래그로 분류될 수 있다. 서냉슬래그는 화학조성이 급냉슬래그와 유사하고 염기도가 높아 콘크리트용 혼화재료로 사용될 경우, 콘크리트 중 수산화칼슘과의 잠재수경성 발현에 유리하여 콘크리트 포장용 결합재로써 활용이 가능할 것으로 보고되고 있으며, 서냉슬래그의 물리화학적 특성을 기반으로 하여 서냉슬래그를 콘크리트 포장재료로써 활용하기 위한 몇몇의 연구가 진행되어 오고 있다. 본 연구에서는 서냉슬래그를 콘크리트 포장재료로 사용하여 공시체를 제조하였으며, 콘크리트의 공학적 특성을 실험적으로 평가함으로써, 서냉슬래그의 콘크리트 포장재료로써 적용가능성을 실험적으로 검토하였다.

숏크리트 모르타르의 성능에 대한 급결제 종류 및 고로슬래그 미분말 대체율의 영향

이승태,김성수,김동규,박광필 한국구조물진단유지관리공학회 2013 한국구조물진단유지관리공학회 논문집 Vol.17 No.1

본 연구에서는 alkali-free 및 aluminate 급결제를 사용한 OPC 및 GGBFS 숏크리트 모르타르의 응결특성, 강도특성, 전기저항성 및 염소이온 침투저항성을 실험적으로 고찰하였다. 실험결과에 따르면, alkali-free 급결제를 첨가한 GGBFS 모르타르는 응결시간 및 압축강도가 GGBFS 대체율에 관계없이 OPC 모르타르와 유사하게 나타났으나, aluminate 급결제를 첨가한 모르타르의 경우, GGBFS 대체율이 증가할수록 응결시간 및 압축강도가 크게 나타나는 경향을 보였다. 한편, 숏크리트 모르타르의 전기저항성 및 염소이온 침투저항성은 GGBFS를 50% 이상 대체한 모르타르가 우수한 경향을 나타내므로써, 적절한 대체율의 GGBFS를 사용한 모르타르가 숏크리트용 재료로써 우수한 성능을 나타낼 것으로 판단된다. In this study, some engineering properties of OPC and GGBFS shotcrete mortars with alkali-free or aluminate accelerator were experimentally examined. As a result, GGBFS mortars with alkali-free accelerator were significantly similar to OPC mortars with same accelerator with respect to both setting time and compressive strength. Comparatively, GGBFS mortars with aluminate accelerator showed a good performance with an increased replacement of GGBFS. Furthermore, when replaced with GGBFS over 50%, the mortars exhibited superior performances of electrical resistivity and chloride ions penetration resistance. Accordingly, it is suggested that GGBFS has a beneficial effect as shotcreting materials in the condition of proper replacement levels.

여성호르몬 분비 부신피질암

이승태,박범진,김대성,남정수,이영구,박흥원,김기경,유종우 大韓泌尿器科學會 2003 Korean Journal of Urology Vol.44 No.10

Performance of Mortars Exposed to Different Sulfate Concentrations

이승태 대한토목학회 2012 KSCE Journal of Civil Engineering Vol.16 No.4

This paper reports an experimental study on the sodium sulfate resistance of three Portland cements with various cement compositions (C3A or silicate ratio) and blended cements incorporating 50% Ground Granulated Blastfurnace Slag (GGBS) or 20%Pulverized Fuel Ash (PFA). In order to evaluate effect of solution concentrations on the deterioration of mortar specimens, the test solutions used were 0.5%, 1.5% and 5% as sodium sulfate. The resistance of mortar specimens was evaluated using visual examination, expansion and compressive strength loss measurements. Additionally, in order to classify sulfate products formed during sulfate attack, microstructural analysis such as X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were also conducted on paste samples exposed to highly concentrated sulfate solution. Results confirmed that in additions to C3A content,Silicate Ratio (SR) of Portland cements is a critical parameter influencing sulfate resistance. Besides, the use of mineral admixtures such as GGBS and PFA led to the being beneficial in reducing the susceptibility to sodium sulfate attack. All the tests reported in the study were carried out at room temperature.

실리카퓸을 혼합한 시멘트 콘크리트의 역학적 특성 및 내구성

이승태,이승헌,Lee, Seung-Tae,Lee, Seung-Heun 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.5

This paper presents the results of experimental work on both mechanical properties and durability of concrete or mortar incorporating silica fume. The aim of this study was to investigate the effect of replacement of silica fume on the performance of hardened concrete or mortar. The replacement levels of silica fume that replaced cement in this work were 0%, 5%, 10% and 15%, respectively. The results of this study indicate that both mechanical properties and durability of concrete are greatly dependent on the replacement levels of silica fume. As the replacement level of silica fume increased, the mechanical properties including compressive and flexural strengths, and static modulus of elasticity were proportionally enhanced. Furthermore, it was found that silica fume had some beneficial effects on the resistances to both chloride ions penetration and sodium sulfate attack. However, it exhibited poor resistances to both freezing-thawing action and magnesium sulfate attack.

남북 경제공동체 구상 : 상허사상에서 실현 가능성 모색

이승태 건국대학교 2000 常虛思想 Vol.11 No.-

전립선 특이 세포막 당단백이 혈관신생에 미치는 영향

이승태,이영구,박흥원 대한비뇨의학회 2004 Investigative and Clinical Urology Vol.45 No.11

Purpose: PSMA(prostate specific membrane antigen) is a transmembrane glycoprotein, which is isolated from LNCaP. It is reported that PSMA is expressed in the vascular endothelium of various tumor. It has been suggested that PSMA can be related to angiogenesis. Herein, the effect of PSMA on angiogenesis was investigated with the HUVEC(human umbilical vein endothelial cell) line transfected with PSMA. Materials and Methods: mRNA was extracted from LNCaP. RT-PCR for PSMA ORF(open reading frame) was performed. PSMA ORF cDNA was subcloned into PcDNA 3.1(-)(BamH1 and Xba1 site) and transfection of PSMA on HUVEC was performed. HUVEC was plated onto a Matrigel coated 6 well plate and incubated at 37oC in a CO2 incubator for 18 hours. The HUVEC tube formation was observed every 2 hours using an inverted microscope. HUVEC cell protein was extracted immediately, and 3 and 6 hours after transfection. Western blot for VEGF(vascular endothelial growth factor) was performed. Results: The tube formation stage of HUVEC transfected with PSMA was observed 10 hours after incubation on Matrigel coating, whereas in the control HUVEC, the cord formation stage was observed after up to 10 hours incubation. The HUVEC transfected with PSMA showed an earlier tube formation stage than the control. Western blot analysis showed that PSMA transfection on HUVEC increased the expression of VEGF 2.5 fold in 3 hours and 1.89 fold in 6, as measured by densitometry. Conclusions: PSMA transfection on the HUVEC cell line induced an initial increase in the expression of VEGF, and subsequently stimulated an earlier tube formation in the HUVEC cell line. These data suggest PSMA is related to angiogenesis. (Korean J Urol 2004;45:1162-1166)

Clinical Features and Mutations in the ENG, ACVRL1, and SMAD4 genes in Korean Patients with Hereditary Hemorrhagic Telangiectasia

이승태,김지아,장신이,김덕경,도영수,서기영,김종원,기창석 대한의학회 2009 Journal of Korean medical science Vol.24 No.1

Hereditary hemorrhagic telangiectasia (HHT) is an inherited disorder that is characterized by abnormal communication between the arteries and veins in the skin, mucosa, and various organs. HHT has been reported to show significant phenotypic variability and genetic heterogeneity with wide ethnic and geographic variations. Although mutations in the endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1) genes have been known to cause HHT for more than 10 yr, little is known about the clinical features or genetic background of Korean patients with HHT. In addition, mutations in mothers against decapentaplegic homolog 4 (SMAD4) are also seen in patients with the combined syndrome of juvenile polyposis and HHT. This study examined five Korean patients with the typical manifestations of HHT such as frequent epistaxis and pulmonary arteriovenous malformations. Direct sequencing of the ENG and ACVRL1 genes revealed one known mutation, ENG c.277C>T, in one patient and two novel mutations, ENG c.992-1G>C and ACVRL1 c.81dupT in two patients, respectively. The remaining two patients with negative results were screened for SMAD4 mutations as well as gross deletions of ENG and ACVRL1 using multiple ligation-dependent probe amplification, but none was detected. Despite the small number of patients investigated, we firstly report Korean patients with genetically confirmed HHT, and show the genetic and allelic heterogeneity underlying HHT.