• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.113-121
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• 2004

A test program was conducted on full-scale steel moment connections constructed using a T-stiffener. In the T-stiffener connection, the beam-to-column connection was reinforced with the horizontal and vertical element of the T-stiffener to resist moment under severe cyclic loads. A total of five specimens were tested in this study together with a concrete-filled tubular(CFT) column(${\sqsubset}-500{\times}500{\times}12$) and a steel beam($H-506{\times}201{\times}11{\times}19$). For the specimens, the T-stiffener was combined with RBS (also known as "Dog-bone") detail or Horizontal Element Hole(HEH) detail constructed to enhance deformation capacity. The test program showed excellent seismic performance for specimens constructed with an RBS or an HEH. except the specimens had brittle failure of VE. The test results also showed that the connections all developed maximum moments at the face of the column. Such moments were at least 15% and as much as 36% larger than the plastic moment capacity of the beam. based on the actual yield stress of the beam steel.

• Journal of Microbiology and Biotechnology
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• v.16 no.5
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• pp.695-703
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• 2006

The dissolved oxygen level of any cell culture environment has a critical effect on cellular metabolism. Specifically, hypoxia condition decreases cell viability and recombinant protein productivity. In this work, to develop CHO cells producing recombinant protein with high productivity, mammalian expression vectors containing a human tissue-type plasminogen activator (t-PA) gene with hypoxia response element (HRE) were constructed and stably transfected into CHO cells. CHO/2HRE-t-PA cells produced 2-folds higher recombinant t-PA production than CHO/t-PA cells in a $Ba^{2+}-alginate$ immobilized culture, and 16.8-folds in a repeated batch culture. In a non-aerated batch culture of suspension-adapted cells, t-PA productivity of CHO/2HRE/t-PA cells was 4.2-folds higher than that of CHO/t-PA cells. Our results indicate that HRE is a useful tool for the enhancement of protein productivity in mammalian cell cultures.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.143-152
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• 1995

This study was performed, by Finite Element Method, to evaluate the stress distribution on the periodontal tissue according to activation of the various closing loops and to predict the pattern of movement of maxillary incisors. At the same time, bull loop, key-hole loop, T-loop, combination loop and asymmetrical T-loop which were used for retraction of maxillary incisors was analysed by Finite Element Method. The following results were obtained 1. Horizontal force was the greatest in bull loop, the followed by key-hole loop, combination loop, T-loop and initial tooth movement exhibited uncontrolled tipping. 2. Horizontal force in asymmetrical T-loop compared to other closing loops was remarkably decreased, and the intrusive force on the incisors occurred. 3. As torque was increased, the moment was increased as a linear increment. 4. As moment was increased, initial movement of tooth changed to root movement from uncontrolled tipping.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.2022-2032
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• 1999

In recent years, the subject of remaining life assessment has drawn considerable attention in the power generation industry. In power generation systems a variety of structural components, such as steam pipes, turbine rotors, and superheater headers, typically operate at high temperatures and high pressures. Thus a life prediction methodology accounting for fracture and rupture is increasingly needed for these components. For accurate failure assessment, in addition to the single parameter such as K or J-integral used in traditional fracture mechanics, the second parameter like T-stress describing the constraint is needed. The most critical defects in such structures are generally found in the form of semi-elliptical surface cracks in the welded piping-joints. In this work, selecting the structures of surface-cracked plate and straight pipe, we first perform line-spring finite element modeling, and accompanying elastic-plastic finite element analyses. We then present a framework for including constraint effects (T-stress effects) in the R6 failure assessment diagram approach for fracture assessment.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.88-97
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• 1994

We describe the design, fabrication, and performance of the optical fiber-photodiode 1$\times$12 arry module using mesa-type InS10.53T GaS10.47TAS/INP 1$\times$12 PIN photodiode array. We fabricated the PIN PD array for high-speed optical fiber parallel data link optimizing quantum efficiency, operating speed sensitivity from the PIN-FET structure, and electrical AC crosstalk. For each element of the array, the diameter of the photodetective area is 80 $\mu$m, the diameter of the p-metal pad is 90 $\mu$m, and the photodiode seperation is 250 $\mu$m to use Si v-groove. Ground conductor line is placed around diodes and p-metal pads are formed in zigzag to reduce Ac capacitance coupling between array elements. The dark current (IS1dT) is I nA and the capacitance(CS1pDT) is 0.9 pF at -5 V. No signifcant variations of IS1dT and CPD from element to element in the array were observed. We calulated the coupling efficiency for 10/125 SMF and 50/125 GI MMF, and measured the responsivity of the PD array at the wavelength is 1.55 $\mu$ m. Responsivities are 0.93 A/W for SMF and 0.96 A/W for MMF. The optical fiber-PD array module is useful in numerous high speed digital and analog photonic system applications.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.61-66
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• 2008

It is important to calculate the exact crack opening area in the cracked pipe subjected to axial force and bending moment. Among many solutions for obtaining the crack opening displacement, Paris-Tada's expression, which is derived from energy method, is open used in fracture analysis for piping crack problems because of its simplicity. But Paris-Tada's equation has conservativeness when radius over thickness ratio(R/t) is ten or less, for it is based on the stress intensity factor solution having a compliance function derived from a simple shell theory. In this paper we derived a new expression using a different stress intensity factor solution which is able to consider the variation of compliance through wall thickness in a cracked pipe. Conservativeness of both equations was examined and compared to finite element analysis results. Conservativeness of the new equation is decreased when R/t > 10 and increased slightly when R/t < 10 compared with Paris-Tada's. But Both equations were highly conservative when R/t < 10 compared with finite element analysis results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.541-542
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• 2012

• Journal of KSNVE
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• v.10 no.3
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• pp.517-522
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• 2000

This study is concerned with the acoustic characteristics for recently developed interference-type noise barrier (T-shaped). To modify the previous shape more conveniently the T-shaped noise barrier with tuning partitions was examined in detail by varying the number and the hight of tuning partitions. The 2-D boundary element method(BEM) analysis were compared with the experimental results of 1/10 reduced scale model.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.228-230
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• 2009

The moment-of-fluid (MOF) method is a new volume-tracking method that accurately treats evolving material interfaces. Based on the moment data (volume and centroid) for each material, the material interfaces are reconstructed with second-order spatial accuracy in a strictly conservative manner. The MOF method is coupled with a stabilized finite element incompressible Navier-Stokes solver for two fluids, namely water and air. The effectiveness of the MOF method is demonstrated with a free-surface dam-break problem.

• The Mathematical Education
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• v.46 no.4
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• pp.493-502
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• 2007

What is a foundational element of plane geometry? Isn't it possible to constitute the contents of plane geometry from that element? In this paper, we suggest a view point that triangle is a foundational element of plane geometry. And take some examples of reconstruction of usually given contents and mathematical activity centered on the triangle in plane geometry.