• Steel and Composite Structures
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• v.9 no.5
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• pp.419-444
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• 2009

Flange and web local buckling in beam plastic hinge regions of steel moment frames can prevent beam-column connections from achieving adequate plastic rotations under earthquake-induced forces. Reducing the flange-web slenderness ratios (FSR/WSR) of beams is the most effective way in mitigating local member buckling as stipulated in the latest seismic design specifications. However, existing steel moment frame buildings with beams that lack the adequate slenderness ratios set forth for new buildings are vulnerable to local member buckling and thereby system-wise instability prior to reaching the required plastic rotation capacities specified for new buildings. This paper presents results from a research study investigating the cyclic behavior of steel I-beams modified by a welded haunch at the bottom flange and reinforced with glass fiber reinforced polymers at the plastic hinge region. Cantilever I-sections with a triangular haunch at the bottom flange and flange slenderness ratios higher then those stipulated in current design specifications were analyzed under reversed cyclic loading. Beam sections with different depth/width and flange/web slenderness ratios (FSR/WSR) were considered. The effect of GFRP thickness, width, and length on stabilizing plastic local buckling was investigated. The FEA results revealed that the contribution of GFRP strips to mitigation of local buckling increases with increasing depth/width ratio and decreasing FSR and WSR. Provided that the interfacial shear strength of the steel/GFRP bond surface is at least 15 MPa, GFRP reinforcement can enable deep beams with FSR of 8-9 and WSR below 55 to maintain plastic rotations in the order of 0.02 radians without experiencing any local buckling.

• Journal of Pharmaceutical Investigation
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• v.36 no.3
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• pp.169-174
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• 2006

The aim of this work was to prepare tenoxicam-ethanolamine salt with improved physicochemical properties for transdermal application. Tenoxicam-ethanolamine salt was prepared in methylene chloride and its physicochemical properties were investigated by DSC and FT-lR. The broad peak of tenoxicam around 3600-3200 $cm^-1$ was shifted to lower wavenumber and more broadened. The characteristic endothermic melting peak of tenoxicam appeared at $223^{\circ}C$. The melting peak of tenoxicam-ethanolamine salt was shifted to $159^{\circ}C$. In contrast to relatively small difference in the partition coefficients of tenoxicam and the tenoxicam-ethanolamine salt, large difference in aqueous solubility was observed. $Crovol^{\circledR}$ PK4O (PEG-12 palm kernel glycerides) provided the highest skin flux for both compounds. The order of the enhancing effect of the various vehicles tested was similar for tenoxicam and tenoxicam-ethanolamine salt, which indicated that their enhancing mechanism for tenoxicam and tenoxicam-ethanolamine salt is similar. Tenoxicam-ethanolamine salt had a higher skin flux than tenoxicam by 1.2- to 31.7-fold, depending on the vehicles used. It is suggested that the vehicles with medium HLB value, 1 double bond, and lower ethylene oxide chain length have a better ability to modify the permeability of the stratum corneum and to promote the effective penetration of tenoxicam and tenoxicam-ethanolamine salt.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.360-366
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• 2006

We have performed density functional theory calculations for the surface structure of O/Pd(100)-p($2{\times}2$), formed by the adsorption of oxygen atoms of 0.25 ML. The oxygen atoms adsorb preferentially at the fourfold hollow site, and the calculated O-Pd bond length is $2,15{\AA}$, The first interlayer spacing ($d_{12}$) of Pd(100) expands by +0.8% due to the oxygen adsorption, which differs from the experimental value of +3.6% reported by a previous LEED study. Assuming that the LEED sample was possibly contaminated by hydrogen atoms, we also examined the effect of hydrogen impurities on the surface structure. Hydrogen atoms adsorbed on O/Pd(100)-p($2{\times}2$) are found to result in large expansions of $d_{12}$ of Pd(100). Our analysis estimates the amount of hydrogen atoms remaining on the LEED sample as -0.3 ML.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1038-1045
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• 2006

The Green Wall is highest eco-system among a segmental retaining wall systems. Recently, the demand of high segmental retaining wall (SRW) is increased in domestic. The soil nailing system is applied in order to maintain the high SRW stability for steeper slope. However, the proper design approach that can consider the earth pressure reduction effects in soil nailing system has not been proposed. This study was performed to introduce the design case by 'Two-Body Translation mechanism' to be able to consider distribution of earth pressure in the soil nailing when designing the green wall using soil nailing system. Also, this study attempts to evaluate the earth pressure change when advanced soil nailing system is constructed using $FLAC^{2D}$ ver. 3.30 program and 'Two-Body Translation mechanism'. Also in this study, various parametric studies using numerical methods as shear strength reduction (SSR) technique and limit equilibrium technique were carried out. In the parametric study, the length ratio and the bond ratio of the soil nailing were changed to identify the earth pressure reduction effect of the retaining wall reinforced by soil nailing.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.25-31
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• 2010

Anchor, soil nail, micropile have been widely used for slope reinforcement and foundation. These all methods need grouting work after placing reinforcing member. In domestic case, gravity fill techniques and pressure grouting techniques are mainly used. In contrast the pressure re-injection grouting method is not commonly used because grouting equipment and lack of practical application example is short and the verification of reinforcing effect is difficult. Pressure re-injection grouting is a kind of post grouting which technique increases the radial stresses acting on the grout body and causes irregular surface to be developed around bond length that tends to interlock the grout and the ground. In this study, the field test was performed to evaluate the reinforcing effect with the variation of grouting methods and pullout characteristics of reinforcing member placed by pressure re-injection grouting method. The test results showed that the post-grouting methods were useful to increase the pullout capacity.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.271-271
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• 2014

본 연구에서는 최근 다양한 전자 소자로써의 연구가 진행되고 있는 그라핀을 SiO2/Si 기판 위에 전자빔 식각(Electron-Beam Lithography)을 이용하여 후면 게이트 전극 구조의 그라핀 채널을 갖는 삼단자 소자를 형성하고 가스 유입이 가능한 진공 Probe Measurement System을 이용하여 금속 전극과 그라핀 간의 접촉저항 (Rc) 및 길이가 다른 채널저항(Rch)를 구하고, 채널 길이, 가스 유량, 온도, 게이트 전압에 따른 I-V 변화를 측정함으로써, 후면 게이트 전극 구조의 그라핀 채널을 갖는 삼단자 소자의 가스 센서로서의 가능성을 연구하였다. 후면 게이트 전극 구조의 그라핀 채널을 갖는 삼단자 소자는 전자빔 식각(Electron-Beam Lithography)에 의해 패턴을 제작하고 Evaporator를 이용하여 전극을 증착 하였다. 소자의 소스 (Source)와 드레인 (Drain)은 TLM (Transfer Length Method)패턴을 이용하여 인접한 두 개의 전극간 범위를 변화시키는 형태로 제작함으로써 소스-드레인간 채널 길이가 다르게 하였다. 이 때 전극의 크기는 가로, 세로 각각 $20{\mu}m$, $40{\mu}m$이며 전극간 간격은 $20/30/40/50/60{\mu}m$로 서로 다르게 배열 하였다. 제작된 그라핀 소자는 진공 Probe Measurement System 내에서 게이트 전압(VG)를 변화시킴으로써 VG 변화에 따른 소자의 특성을 평가하였는데, mTorr 상태의 챔버 내로 O2 가스를 주입하여 그라핀의 Dangling bond 및 Defect site에 결합 된 가스로 인한 전기적 특성의 변화를 측정하고, 이 때 가스의 유량을 50 sccm에서 500 sccm 까지 변화시킴으로써 전기적 특성 변화를 측정하여 센서 소자의 민감도를 평가하였다. 또한, 서로 다르게 배열한 소스-드레인 간의 채널 길이로 인하여 채널과의 접촉 면적에 따른 센서 소자의 민감도 또한 평가할 수 있었다. 그리고 챔버 내 온도를 77 K에서 400 K까지 변화시킴으로써 온도에 따른 소자의 작동 범위를 확인하고 소자의 온도의존성을 평가하였다.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.787-793
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• 1996

In this paper, to investigate the effect of the offset ink formulation on deinking of Korean old newspaper, the samples printed with five different types of offset ink were aged naturally for 10, 30, 90, 180 days, and then yield, brightness, fiber length, physical properties(tensile, tear, burst index) were evaluated according to aging time. As the aging time increased, the yield and brightness of respective samples decreased. Particially, as the addition amounts of linseed oil increased, those of samples decreased. Therefore, linseed oil is thought to reduce the deinkability of ink. Also, containing rosin-modified phenolic resin and gilsonite seem to reduce brightness of samples according aging time. In physical properties, tensile index and burst index were roughly decreased, but tear index was increased according to aging time. However, the three indexes of the sample containing only linseed oil as the vehicle component were considerably reduced in comparison with those of other samples, as once crosslinked a strong bond between the ink and fibers was produced and made it difficult to defibrate in producing sheets.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.193-200
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• 1980

The crystal structure of N-acetyl-L-cysteine, $C_5H_9NO_3S,$ has been determined from three dimensional photographic intensity data $(CuK{\alpha}$ radiation) by single crystal X-ray diffraction analysis. There is one formula unit in the triclinic unit cell with a = 7.04(3), b = 5.14(2), c = 8.25(3) ${\AA}$, ${\alpha}$ = 106(2), ${\beta}$ = 51(1), ${\gamma}$ = 124(2)$^{\circ}$ and space group P$_1$, The structure was solved by the direct method and refined by the full matrix least-squares method. The final R value is 12.3% for 629 observed reflections. The C-carboxyl group and the N-acetyl group are very neary planar. The molecule appears to form with neighboring molecules a hydrogen bond, $O-H{\cdot}{\cdot}{\cdot}O(3)$ of length 2.59${\AA}$.

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.74-77
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• 2004

The crystal structure of Dinitroethylenediaminepalladium(II), $Pd(C_2H_8N_2)(NO_2)_2$, has been determined by X-ray crystallography. Crystal data: a=7.425(3), b=8.480(4), c=11.885(2) ${\AA}$, Orthorhombic, $A2_1ma$ (Space Group No=36), Z=4, V=748.3(4) ${\AA}^3,\;D_c=2.295 gcm^{-3},\;{\mu}=2.457mm^{-1}$. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were $R_1=0.0306,\;R_w=0.0802,\;R_{all}=0.0320,\;and\;S=1.166)$ for the observed 377 reflections. Bond lengths and angles of palladium complex are similar to the previously reported data. The complex structure is one dimensional Reiset's salt type analogue showing zigzag chain of Pd-Pd length and angle of 3.762(2) ${\AA}$ and $161.41(5)^{\circ}$. The complex molecules are linked through inter-and intramolecular hydrogen bonds of 3.05(1) and 3.15(1) ${\AA}$ between oxygen and nitrogen.

• Korean Journal of Materials Research
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• v.17 no.4
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• pp.203-206
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• 2007

Effects of doping rare earth elements on Ln site of $Ln_{0.7}Ca_{0.3}MnO_3$ (Ln = N d, Sm and La) were examined from structure, magnetic and electrical properties. Size of a-axis increased as following order of La < Nd < Sm, whereas c-axis was not much changed. Curie temperatures of 170 K for $Nd_{0.7}Ca_{0.3}MnO_3$, 110 K for $Sm_{0.7}Ca_{0.3}MnO_3$ and 250 K for $La_{0.7}Ca_{0.3}MnO_3$ were obtained. This result coincides with change of Mn-O bond length causing by a-axis lattice constant. The highest magnetroresistance ratios were 22% at 77 K for $Sm_{0.7}Ca_{0.3}MnO_3$, 32% at 110 K for $Nd_{0.7}Ca_{0.3}MnO_3$, and 33% at 180 K for $La_{0.7}Ca_{0.3}MnO_3$.