• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.375-384
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• 2005

The goal of this paper is to understand the stress-transfer mechanism of concrete-filled tubular column to H-beam connections with external T-stiffener through the finite element method and to offer basic data for the design of T-stiffener. To identify the problems of previous test results, the same shapes of the full-scale test specimens were modeled for the finite element analysis. Results of the analysis were compared with the test results. Several stress and strain indices were used to understand the stress-transfer mechanism of connection with various T-stiffeners parameters. The models of analysis with different T-stiffener are grouped into TS, TSD, and TSH series. An alternative plan that decreases the stress concentration of beam flange to horizontal stiffener connection is proposed through the elasto-plastic finite element method. The basic design idea and minimum sizes of T-stiffener were proposed based on the various indices in relation to the connection details.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.673-681
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• 2003

This paper describes the experiment that determines the ultimate strength of new uniplanar T-joints made of cold-formed square hollow sections. The new T-joint focused on the configuration of a branch member that is oriented 45 degrees to the plane of the truss and welded to the chord member whose web is stiffened with plate. The strength and failure mode are examined using the existing strength formula for the branch-rotated T-joint $(16.7{\leq}2{\gamma}(B/T){\leq}33.3$ and $0.63{\leq}{\beta}(b1/B){\leq}0.7)$. The test result shows that the capacity of the stiffened joint increases with thicker stiffening plate. The failure mode of the specimen $(2{\gamma}=33.3)$ is stiffened with plate changes from M2 (flange failure) to M3 (combined failure). On the other hand, the failure mode of the specimen $(2{\gamma}=16.7)$ is stiffened with plate changes from M1 ( web failure) to M2 (flange failure)

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.274-274
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• 2010

한국은 국제핵융합실험로 (ITER) 사업에 참여하고 있으며, 삼중수소 증식을 시험하기 위한 시험 모듈(TBM, Test Blanket Module)로서 HCML (Helium Cooled Molten Lithium) TBM을 설계, 개발하고 있다. 헬륨 및 액체 리튬을 냉각재와 증식재로 사용하는 개념으로, 구조재로서 Ferritic Martensitic (FM) 강이 사용될 예정이다. 특히, HCML TBM의 일차벽은 중성자 및 플라즈마로부터 입사되는 입자들을 차폐하기 위한 Be 차폐체와 FM강으로 구성되어 있으며, 일차벽 제작법 개발을 위해서는 Be과 FM강 간의 접합과 FM강 간의 접합 방법이 개발되어야 한다. FM강 간의 접합은 기존의 연구를 통해 접합 조건이 이미 도출되었고, 고열부하 시험을 통해 검증 완료한 상태이다. 그러나, Be과 FM강 간의 접합은 현재 개발단계에 있다. 본 논문에서는 고려 중인 구조재와 Be 차폐체 사이의 접합법 개발을 위해, 고온등방가압(HIP, Hot Isostatic Pressing) 조건을 도출하고, 운전조건과 유사 혹은 가혹한 조건에서 고열부하를 인가하여, 그 건전성을 평가하는 일련의 과정을 기술하였다. 본 연구에서는 Be과 FM강 간의 접합법 개발 및 검증을 위해 제작된 $80{\times}80{\times}1$ Be/FM강 mock-up을 국내에서 구축된 고열부하 시험 장비인 KoHLT를 활용하여 수행한 고열부하 시험에 대한 것이다. 본 mock-up은 $80{\times}80{\times}10mm(t)$의 Be tile 3개를 동일 크기에 두께가 각각 25mm와 50 mm인 FM강과 스테인레스강에 접합된 것으로, 고열부하 장비에 설치하여 고열부하 시험을 수행하였다. 냉각수의 온도 및 속도는 25 C, 0.15 kg/sec로 유지되었고, 열부하는 $0.5\;MW/m^2$로 유지하였다. 시험 조건에 대한 예비해석을 통해, 가열시의 온도 및 stress, strain 분포를 얻었고, 이를 통해, cycle to failure 값을 도출하였다. 1000 사이클의 가열 실험을 마친후 초음파를 활용한 접합 계면의 결함확인 및 파괴검사를 통한 접합 건전성을 확인하였다. 3가지 접합법 모두 일부 접합면이 이탈되었으며, 향후 보다 건전한 접합방법 개발이 진행되어야 할 것으로 보인다.

• The Korean Journal of Nuclear Medicine
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• v.37 no.6
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• pp.402-417
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• 2003

Purpose: To evaluate the use of monoclonal antibody (MoAb) as a carrier of the receptor-binding ligand the receptor mediated uptake into liver and subsequent metabolism of $^{111}In-labeled$ galactosylated MoAb-chelator conjugates were investigated and compared with those of $^{111}In$ labeled MoAb. Materials and Methods : T101 MoAb, $IgG_2$ against human lymphocytic leukemic cell, conjugated with cyclic DTPA dianhydride (DTPA) or 2-p-isothiocyanatobenzyl-6-methyl-DTPA (1B4M) was galactosylated with 2-imino-2-methoxyethyl-1-thio-${\beta}$-D-galactose and then radiolabeled with $^{111}In$. Biodistribution and metabolism study was peformed with two $^{111}In-conjugates$ in mice and rats. Results: $^{111}In-labeled$ T101 and its galactosylated conjugates were taken to the liver by the time, mostly within 10 min. However DTPA conjugate was retained longer in the liver than the 1B4M conjugate (55% vs 20% of injected dose at 44 hr). During this time, the radiornetabolite of DTPA conjugate was excreted similarly into urine (24%) and feces (17%). The radiometabolite of 1B4M was excreted primarily into feces (68%) rather than urine (8%). Size exclusion HPLC analysis of the bile and supernatant of liver homogenate showed two peaks the first (35%) with the retention time (Rt) identical to IgG and the second (65%) with Rt similar to free $^{111}In$ at 3 hr post-injection for the 1B4M conjugate, indicating that the metabolite is rapidly excreted through the biliary system. in contrast to DTPA conjugate, the small $^{111}In-DTPA-like$ metabolite was the major radioindium component (90%) in the liver homogenate as early as 3 hour post-injection, but the cumulative radioindium activity in feces was only 17% at 44 hour, indicating that the metabolite from DTPA conjugate does not clear readily through the biliary tract. Conclusion: The galactosylation of the MoAb conjugates resulted in higher hepatocyte uptake and enhanced metabolism, compared to those without galactosylation. Metabolism of the MoAb-conjugates is different between compounds radiolabled with different chelators due to different characteristics of radiometabolites generated in the liver.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.29-36
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• 2010

To investigate the cyclic characteristics of exterior joints in RC frame buildings which are typically used after 1988, 70% scaled T-shaped beam-column subassemblies were designed and tested with a displacement control that is composed of 9 steps, until 3.5% story drift was reached. Axial forces are applied to columns during the experiment to simulate a real situation. The results show that the non-seismic detailed specimens failed before reaching 0.85% story drift, and their strengths are less than 0.85 times the nominal flexural strength which beam or columns should reach. The relationship of principal stress and story drift of exterior joints is similar to the one that Priestly proposed.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.115-116
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• 2010

To research the fragility of exterior joints of RC frame building which are not designed to seismic design code, four T shaped beam-column subassemblies are designed and tested with displacement control until to reach 3.5% story drift. From the results, the non-seismic detailed specimen failed in exterior joint before to reach to 1.0% drift, which is far less than the recommendation value of FEMA 356 and their strengths are less than 0.85 times of the nominal flexural strength.

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.271-280
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• 2010

This study was programmed to fabricate a beam-to-column connection that is limited to a steel-welded moment connection with full-scale members, using SN steel. A cyclic seismic test was conducted of the nine specimens that were fabricated by choosing the test variable for the weld access hole geometry, connection design method, and RBS. From the test results, failure modes, the moment-drift behavior, and the strain distribution were provided. From the specimen material properties, the beam's nominal plastic flexural capacity and classified qualified connection as a special moment flame were calculated. By analyzing the skeleton part and the baushinger part, a range of strength-raising effects, and deformation ratios were provided, with which the seismic performance of the specimens were evaluated. The test results showed that the specimens eliminated their weld access holes that demonstrated higher seismic performance than the specimens' existing weld access holes, and that the WUF-W connection that was reinforced by the supplemental fillet weld around the shear tap that was fastened by five bolts demonstrated superior seismic performance.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.103.1-103.1
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• 2012

본 연구는 차량경량화를 위하여 높은 인장강도와 우수한 인성을 가지는 590MPa급 이상조직강(Dual phase steel)을 이용하여 1991년 TWI(The Welding Institute)에서 개발된 마찰교반접합을 적용하여 접합을 실시하였다. 접합의 공정조건으로 툴의 회전속도는 250~350 RPM, 접합속도로는 50~350 mm/min로 겹치기접합을 실시하였다. 접합에서 사용된 툴은 Megastir에서 제작한 고융점마찰교반접합용 툴인 PCBN(Q-60)을 이용하였고 연구에 사용된 DP590은 포스코(POSCO)에서 제작된 1.4t(mm) 두께인 AHSS(advanced high strength steels)을 사용하였다. 모재인 DP590과 접합체의 미세조직은 광학현미경과 주사전자현미경을 이용하여 관찰하였으며 기계적 특성은 경도시험과 인장시험을 실시하여 조사하였다. 경도의 분포는 모재에서 약 220~230Hv이며 TMAZ부분에서 상승하기 시작하여 접합부에서 약 320Hv까지 상승하는 경향을 보였으며 인장시험 결과 접합속도 100~200 mm/min에서는 모든 시편이 모재에서 파단되어지는 것을 확인할 수 있었다. 위와 같은 결과 300~350 RPM, 100~200 mm/min의 공정조건에서는 접합이 성공적으로 이루어졌으며 차량경량화에 적용이 가능하다고 판단되어진다.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.211-219
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• 2009

The purpose of the study described in this paper was to experimentally investigate branch squared T joints with cold formed hollow structural sections under the in plane moment in a Vierendeel Truss. The branch in the T joints was welded to the upper flange of the chord. The main experimental parameters were the ratio of the width to the thickness of the chord ($2{\gamma}$), with ${16.7{\leq}2{\gamma}{\leq}33.3}$, and the width ratio of the branch to the chord ($\beta$), with ${0.40{\leq}{\beta}{\leq}0.71}$. Nine specimens were tested and manufactured in joints under the in plane bending moment. Based on the results of the test, the in plane moment strength of the branch squared T joints was determined according to the bending deformation of the chord flange yielding, regardless of the ratio of the width to the thickness of the chord and the ratio of the width of the branch to the width of the chord. Also, the in plane moment strength of the branch squared T joints in the hollow structural sections can be defined as 1.5 times the moment load at M1%B the strength of the joints that governed the serviceability in the control group. Finally, the experimental results with the branch squared T joints show that the in lane moment strength of the joint increased as $2{\gamma}$ decreased and $\beta$ increased.

• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.1-8
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• 2001

The purpose of this study is to examine the utility of concretefilled steel tubular column to H-beam connections with tubular stiffener. As a preliminary step. a tensile experiment was undertaken to scrutinize characteristics of the structural behavior that take place between beam flanges and column with tubular stiffener. A total of 4 types of experimental settings were developed as tabular stiffeners are made up 9, 18, and 27 mm of thickness and 50 and 80 mm of height respetively Along with the overall load subsequently the degree of displacement and strain were recorded. Based on the yield line theory results of this of this study were evaluated and further critically reviewed the applicability of the strength formula. This study found that collapse mechanism was emerged on the beam flange as reinforcing tabular stiffeners Complementary studies of this sort, including numerical analyses should be undertaken in order to develope specific design critera.