• Title/Summary/Keyword: barrier function

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Method of Solving Oxidation Problem in Copper Pillar Bump Packaging Technology of High Density IC (고집적 소자용 구리기둥범프 패키징에서 산화문제를 해결하기 위한 방법에 대한 연구)

  • Jung, One-Chul;Hong, Sang-Jeen;Soh, Dae-Wha;Hwang, Jae-Ryong;Cho, Il-Hwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.12
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    • pp.919-923
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    • 2010
  • Copper pillar tin bump (CPTB) was developed for high density chip interconnect technology. Copper pillar tin bumps that have $100{\mu}m$ pitch were introduced with fabrication process using a KM -1250 dry film photoresist (DFR), copper electroplating method and Sn electro-less plating method. Mechanical shear strength measurements were introduced to characterize the bonding process as a function of thermo-compression. Shear strength has maximum value with $330^{\circ}C$ and 500 N thenno-compression process. Through the simulation work, it was proved that when the copper pillar tin bump decreased in its size, it was largely affected by the copper oxidation.

The Meeting Plaza Design around "Myeonmok" Subway Station, Seoul (면목역 만남의 광장 설계)

  • Kim, Sung-Kyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.35 no.1 s.120
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    • pp.20-27
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    • 2007
  • This paper presents a landscape design for the meeting plaza around the "Myeonmok" subway station. The site is located at 120-1 Myeonmok 1-dong, Jnngrang-gu, Seoul, and its area is approximately $2,664.7m^2$. The goal of the design was to make an environmentally friendly meeting and rest place which was related to the subway station. To achieve this goal, concepts of history, tradition, sense of place, community, environmental friendliness, and function were developed. For history, stone sculpture and art tiles symbolizing the paleolithic area were introduced because the site is located near an archaeological site of paleolithic min. For tradition, considering that the site is a 'sailing ship' form in terms of Pungsu theory, a sculpture symbolizing a sailing ship and paving patterns symbolizing waves were introduced. For asense of place, a grass hill, a waterfall and a pond symbolizing an old meadow for horse pasture was introduced. In addition, a multi-purpose round plaza as a meeting place for local community and subway users was proposed. A zelkova grove symbolizing a village forest was proposed for a restand relaxation area. All areas were designed to be environmentally friendly and barrier-free. Concepts for a defensible space wereadapted for safety because the site was a crime-prone area.

Identification of Differentially Expressed Proteins in Imatinib Mesylate-resistant Chronic Myelogenous Cells

  • Park, Jung-Eun;Kim, Sang-Mi;Oh, Jong-K.;Kim, Jin-Y.;Yoon, Sung-Soo;Lee, Dong-Soon;Kim, Young-Soo
    • BMB Reports
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    • v.38 no.6
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    • pp.725-738
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    • 2005
  • Resistance to imatinib mesylate (also known as Gleevec, Glivec, and STI571) often becomes a barrier to the treatment of chronic myelogenous leukemia (CML). In order to identify markers of the action of imatinib mesylate, we used a mass spectrometry approach to compare protein expression profiles in human leukemia cells (K562) and in imatinib mesylate-resistant human leukemia cells (K562-R) in the presence and absence of imatinib mesylate. We identified 118 differentially regulated proteins in these two leukemia cell-lines, with and without a $1\;{\mu}M$ imatinib mesylate challenge. Nine proteins of unknown function were discovered. This is the first comprehensive report regarding differential protein expression in imatinib mesylate-treated CML cells.

Effect of Enhancers on the Electrical Properties of Skin: The Effect of Azone and Ethanol

  • Oh, Seaung-Youl;Guy, Richard H.
    • Journal of Pharmaceutical Investigation
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    • v.24 no.3
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    • pp.41-47
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    • 1994
  • The effect of Azone and ethanol on the electrical properties of human and hairless mouse skin was studied and the results were compared. The complex electrical impedance was measured as a function of frequency, and resistance and capacitance were determined from Nyquist plot. After the treatment of human-heat separated epidermis with Azone, contrary to the expectation, resistance increased about 60% and it did not change with time. Capacitance also increased; immediately after the treatment, it was about 110% of pretreatment value and it increased further with time. On the other hand, when hairless mouse skin was treated with Azone, marked changes occured; resistance fell almost to the value of bathing medium itself and capacitance increased to about 200% of its pretreatment value. Similar result were obtained when hairless mouse skin was treated with 100% ethanol. The results suggest that there are differences in the strength of barrier properties of stratum corneum (SC) between human and hairless mouse skin. Overall, the results provide further mechanistic insight into ion conduction through the skin and into the role of SC lipids in skin capacitance.

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Analysis on running safety of train on bridge with wind barriers subjected to cross wind

  • Zhang, T.;Xia, H.;Guo, W.W.
    • Wind and Structures
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    • v.17 no.2
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    • pp.203-225
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    • 2013
  • An analysis framework for vehicle-bridge dynamic interaction system under turbulent wind is proposed based on the relevant theory of wind engineering and dynamics. Considering the fluctuating properties of wind field, the stochastic wind velocity time history is simulated by the Auto-Regressive method in terms of power spectral density function of wind field. The bridge is represented by three-dimensional finite element model and the vehicle by a multi-rigid-body system connected by springs and dashpots. The detailed calculation formulas of unsteady aerodynamic forces on bridge and vehicle are derived. In addition, the form selection of wind barriers, which are applied as the windbreak measures of newly-built railways in northwest China, is studied based on the suggested evaluation index, and the suitable values about height and porosity rate of wind barriers are studied. By taking a multi-span simply-supported box-girder bridge as a case study, the dynamic response of the bridge and the running safety indices of the train traveling on the bridge with and without wind barriers are calculated. The limit values of train speed with respect to different wind velocities are proposed according to the allowance values in the design code.

Interannual Variabilities of Sea Surface Temperature and Sea Level Anomaly related to ENSO in the Tropical and North Pacific Ocean System (열대 및 북태평양에서 ENSO와 관련된 표층수온과 해면고도의 경년 변동성)

  • Kim, Eung;Jeon, Dong-Chull
    • Ocean and Polar Research
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    • v.30 no.3
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    • pp.313-324
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    • 2008
  • In order to understand the variation of ENSO-related oceanic environments in the tropical and North Pacific Ocean, spatio-temporal variations of sea surface temperature anomaly (SSTA) and sea surface height anomaly (SSHA) are analyzed from distributions of complex empirical orthogonal functions (CEOF). Correlations among warm pool variation, southern oscillation index, and ocean surface currents were also examined with respect to interannual variability of the warm pool in western tropical Pacific. Spatio-temporal distributions of the first CEOF modes for SSTA and SSHA indicate that their variabilities are associated with ENSO events, which have a variance over 30% in the North Pacific. The primary reasons for their variabilities are different; SST is predominantly influenced by the change of barrier layer thickness, while SSH fluctuates with the same phase as propagation of an ENSO episode in the zonal direction. Horizontal boundary of warm pool area, which normally centered around $149^{\circ}E$ in the tropics, seemed to be expanded to the middle and eastern tropical regions by strong zonal currents through the mature phase of an ENSO episode.

Improvement of Permeability to Organic Solvent in Escherichia coli for a Toxicity Biosensor

  • Bae, Hee-Kyung;Shin, Pyong-Kyun;Song, Bang-Ho
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2001.06b
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    • pp.14-16
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    • 2001
  • The outer membrane (OM) of gram-negative bacteria acts as an effective permeability barrier against noxious agents including several antibiotics and organic solvents, and lipopolysaccharide (LPS) is the key molecule for this function. Outer membrane modified mutants (Ml-166, M2-42, M3-21) of E. coli DH5$\alpha$/pBSl were selected through a mutation using EMS (ethyl-methane-sulfonate). Among the selected mutants, M3-21 was twice as sensitive as LumisTo $x^{ }$ to benzene and M2-41 was 8 times as sensitive as LumisTo $x^{ }$ to toluene. To identify the structural change in the membrane by mutation, the relative cell surface hydrophobicities and the absorption of the crystal violet to the organisms were measured. All the mutants absorbed more crystal violet than their parent and the absorption of crystal violet increased in cell walls as carbohydrate of lipopolysaccharide decreased. When the cell surface hydrophobicities of DH5/pBSl and its mutants were measured by the BATH, the hydrophobicities of mutants increased compared to their parent in several organic solvents. The difference of lipopolysaccharide between DH5/pBSl and its mutants was identified by various ways such as the SDS-PAGE gel, the screening of LPS molecular weights, the mass spectrometry, and MALDI-TOF.F.

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Isolation of a Hypoxia/Reoxygenation Regulatory Factor in Rat Astrocytes (흰쥐 성상세포에서 산소농도의존성 유전자의 분리)

  • Park Jeong-Ae;Song Hyun-Seok;Lee Hye-Shin;Kim Kyu-Won
    • YAKHAK HOEJI
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    • v.50 no.2
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    • pp.124-128
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    • 2006
  • Astrocyte has emerged as an active regulator of brain function, which connects between blood vessels and neurons as well as is a structural component of the blood-brain barrier, From its structural characteristics, astrocyte seems to sensitively respond to oxygen tension, and, in turn, generate diverse cellular cascades. Therefore, to reveal astrocytlc events by oxygen change, we screened genes whose expressions are upregulated under reoxygenation after hypoxic stress using cDNA representational difference analysis (RDA) technique. Meteorin that regulates glial differentiation was isolated from primary cultured rat astrocytes as a hypoxia/reoxygenation regulatory factor. We cloned rat version of Meteorin (rMe-teorin) and determined full-size sequences of rMeteorin. In addition, RT-PCR analysis revealed that Meteorin was increased under reoxygenation in astrocytes and highly expressed in the developing brain. Collectively, these results suggest that Meteorin may regulate astrocyte-mediated effects in response to the change of oxygen tension in the pathophysiological states.

Modeling Demand for Rural Settlement of Urban Residents (도시민의 농촌이주 수요모형 분석: 정착자금 지원효과를 중심으로)

  • Lee, Hee-Chan
    • Journal of Korean Society of Rural Planning
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    • v.15 no.2
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    • pp.97-110
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    • 2009
  • The objective of this research was to develop a rural settlement demand model to analyze the determinants of settlement demand of urban residents. The point aimed at from model development was deriving stated preference of potential consumers towards rural settlement through setting a hypothetical market, and using settlement subsidy as a surrogate variable for price in the demand model. The adequate demand model deducted from hypothetical market data was derived from the basis of Hanemann's utility difference theory. In the rural settlement demand model, willingness to accept was expressed by a function of settlement subsidy. Data utilized in the analysis was collected from surveys of households nationwide. According to inferred results of the demand model, settlement subsidy had a significant influence on increasing demand for rural settlement. A significant common element was found among variables affecting demand increase through demand curve shift. The majority group of those with high rural settlement demand sought agricultural activity as their main motive, due to harsh urban environments aggravated by unstable job market conditions. Subsequently, restriction of income opportunities in rural areas does not produce an entrance barrier for potential rural settlers. Moreover, this argument could be supported by the common trend of those with high rural settlement demand generally tending to have low incomes. Due to such characteristics of concerned groups of rural settlement demand, they tended to react susceptibly to the subsidy provided by the government and local autonomous entities.

Proximity Effect in Nb/Gd Layers

  • Jung, Dong-Ho;Char, K.
    • Progress in Superconductivity
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    • v.12 no.2
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    • pp.110-113
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    • 2011
  • We have grown a Nb/Gd bilayer on a$SiO_2$/Si substrate by using a DC magnetron sputtering system, which was fabricated in situ with silicon stencil masks. In order to investigate proximity effect of the Nb/Gd bilayer, we used a planar tunnel junction with an AlOx tunnel barrier by oxidizing the Al ground electrode at the bottom. A $Co_{60}Fe_{40}$ backing of Al was deposited so as to reduce the superconductivity of the Al, ensuring a normal counterelectrode. With a 50-nm-thick Nb layer, we have measured dI/dV (dynamic conductance) by varying the thickness of Gd, which can reveal the density of states (DOS) of the Nb/Gd bilayer as a function of the Gd thickness resulting from the proximity effect of a superconductor/ferromagnet bilayer (S/F). The SF proximity effect in Nb/Gd will be discussed in comparison to our previous results of the CoFe/Nb, Ni/Nb and CuNi/Nb proximity effect; Gd is expected to show different effects since Gd has f-electrons, while CoFe, Ni, and CuNi have only d-electrons. Our studies will focus on the triplet correlation in a superconducting pair.