• Structural Engineering and Mechanics
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• v.87 no.5
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• pp.405-418
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• 2023

This study focused on the effectiveness of seismic isolation technique in case of a reinforced concrete structure with soft story defined as the stiffness irregularity between adjacent stories. In this context, a seismically isolated 3-story reinforced concrete structure was analyzed by gradually increasing the first story height (3.0, 4.5, and 6.0 m). The seismic isolation system of the structure is assumed to be composed of lead rubber bearings (LRB). In the analyses, isolators were modeled by both deteriorating (temperature-dependent analyses) and non-deteriorating (bounding analyses) hysteretic representations. The deterioration in strength of isolator is due to temperature rise in the lead core during cyclic motion. The ground motion pairs used in bi-directional nonlinear dynamic analyses were selected and scaled according to codified procedures. In the analyses, different isolation periods (Tiso) and characteristic strength to weight ratios (Q/W) were considered in order to determine the sensitivity of structural response to the isolator properties. Response quantities under consideration are floor accelerations, and interstory drift ratios. Analyses results are compared for both hysteretic representations of LRBs. Results are also used to assess the significance of the ratio between the horizontal stiffnesses of soft story and isolation system. It is revealed that seismic isolation is a viable method to reduce structural damage in structures with soft story.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.444-448
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• 2007

The effects of intra-particle composition on the adhesive properties and water dispersity of acrylic emulsion type pressure sensitive adhesives (PSAs) were investigated. In the case of PSA having uniform intra-particle composition, the higher holding strength made the water dispersity lower. By changing the intra-particle composition in hard core/soft shell type, however, it was possible to get PSAs showing both high holding strength and water dispersity. When the weight ratio of MAA/AA is 4/1, high holding strength, but low initial tack and very low water dispersity were observed in both cases of higher contents of (AA+MAA) in core and shell area. When the weight ratio of MAA/AA is 1/4, however, higher water dispersity and lower holding strength were indicated in the case of higher contents of (AA+MAA) in shell area.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.323-327
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• 2017

Soft magnetic composite (SMC) material has recently received a significant attention in the area of high-speed machines because of its unique properties such as good design flexibility and low eddy current loss. However, SMC's electromagnetic property is poor compared to silicon steel in terms of saturation, relative permeability, and hysteresis loss. This paper presents a technique for utilization of SMC in two strategic designs of a switched reluctance machine (SRM) depending on a loss pattern. To investigate the effect of SMC's merits and demerits, the stator material is changed from laminated steel to SMC.

• Molecules and Cells
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• v.45 no.2
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• pp.76-83
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• 2022

Neurons-on-a-Chip technology has been developed to provide diverse in vitro neuro-tools to study neuritogenesis, synaptogensis, axon guidance, and network dynamics. The two core enabling technologies are soft-lithography and microelectrode array technology. Soft lithography technology made it possible to fabricate microstamps and microfluidic channel devices with a simple replica molding method in a biological laboratory and innovatively reduced the turn-around time from assay design to chip fabrication, facilitating various experimental designs. To control nerve cell behaviors at the single cell level via chemical cues, surface biofunctionalization methods and micropatterning techniques were developed. Microelectrode chip technology, which provides a functional readout by measuring the electrophysiological signals from individual neurons, has become a popular platform to investigate neural information processing in networks. Due to these key advances, it is possible to study the relationship between the network structure and functions, and they have opened a new era of neurobiology and will become standard tools in the near future.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.311-315
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• 2006

Various core shapes of cylindrical drains are used for accelerating primary consolidation for soft clay deposits, but serious harmful disadvantages on drainage capacity may occur on cylindrical drains due to confining Pressure when they are installed in that soil. In this study, two different core shapes of cylindrical drain are used to evaluate the drainage capacity with consideration of clogging effects on their filter jackets for an applied confining pressure. Column tests with radial drainage system were conducted under confining pressure of 50 kPa for 13 days. Two parameters which are discharge and accumulated volume of water drained were measured as the time elapsing. From this experimental study, the results showed that at the Initial stage before the clogging developed enough, the cylindrical drain with angular-type-plastic-core could produce discharge twice higher (maximum) than those with round-type. After 13 days had passed on, cylindrical drain with angular-type-plastic-core could produce discharge only 20% higher than those with round-type one. Eventually, there is a possibility that the efficiency of using angular-type-cylindrical-drain will be similar to the round-type one as the clogging develops more.

• Journal of the Korean Magnetics Society
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• v.7 no.4
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• pp.180-185
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• 1997

Variations of core loss and coercivity with heat treatment condition have been studied in amorphous ribbon core specimens. All measurements were performed at 10 kHz with a maximum induction of 0.1 T. With increasing annealing time, both core loss and coercivity of core specimens decreased first, reaching minimum values, and increased thereafter. Specimen heat treated in an air showed better soft magnetic properties than those treated in Ar atmosphere. The specimens annealed under magnetic field higher than 6 Oe in radial direction showed reduced core loss and coercivity. The field annealing effects were increased with increasing cooling rate near Curie temperature of the material. The specimen annealed under an applied field in perpendicular direction of the core showed increased coercivity and decreased permeability.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.116-117
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• 2010

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.281-292
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• 2008

Prefabricated Board Drains (PBDs) recently become more widely used than conventional sand drains in improving soft ground because the PBD is more time and cost effective. The performance of PBDs is affected by disturbance in the adjacent soil formation during inserting mandrels, the intrusion of fine particles into filter fabric, and necking of the drain by excessive lateral pressure especially occurring in very deep clay formation such as the Busan New Port site. In this study, the PBD with double-core is introduced, which seems to overcome the shortcomings of usual single-core PBDs. An in-situ test program was established in the Busan New Port site, in which a set of the double-core PBDs and the single-core PBDs was installed to compare the efficiency of each of the drains. The discharge capacity of the double-core and the single-core PBDs was compared for various confining pressures in the modified Delft test and the chamber test. A series of CRS consolidation tests was performed in order to obtain profiles of void ratio-effective stress and void ratio-permeability relationships in the Busan New Port site that are used as input date in performing a numerical program ILLICON. The numerically simulated settlements of ground surface in the test site are in good agreement with those of in-situ measurements. In addition, the performance of the double-core and single-core PBDs has been experimentally and numerically compared in this paper.

• IMMUNE NETWORK
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• v.6 no.1
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• pp.20-26
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• 2006

Background: Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disease that is characterized by invasive synovial hyperplasia, leading to progressive joint destruction. Recent studies have described that RA is caused by virus, bacteria or outside material. Approximately 2 to 20% of RA cases arc reported to be associated with infected hepatitis C virus (HCV). However, the mechanisms underlying virus-induced RA are still unknown. Moreover, few molecular studies have addressed the inflammatory aspects of HCV-associated autoimmune RA. In this study, we aimed to determine whe ther or not another HCV core protein transactivates the IL-8 gene expression, prototypic chemokine, in synovial cell. Methods: To establish the HCV core expressing stable synovial cell line, pCI-neo-core, a plasmid encoding HCV core protein, were transfected to HIG-82 cell line that is an established cell line from rabbit periaricular soft tissue. We examined the morphological changes and cell cycle distribution of HIG-82 cells with expression of HCV core protein by inverted microscopy and flow cytometry analysis, respectively. Also, we determined the mRNA levels of Interleukin (IL)-6 and IL-8 related to the inflammation by RT-PCR and then analyzed regulation of IL-8 expression by the NF-${\kappa}B$ pathway. Results: Our study showed no significant differences in morphology and cell cycle between HIG-82 control cell line and HIG-82 expressing HCV core protein. However, expression of HCV core protein induces the IL-8 mRNA expression in HIG-82 core cells via activated NF-${\kappa}B$ pathway. Conclusion: These results suggest that HCV core protein can lead to enhanced IL-8 expression. Such a proinflammatory role may contribute to the etiologic pathogenesis in RA patients with HCV infection.

• Journal of Magnetics
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• v.16 no.4
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• pp.431-434
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• 2011

The reduction of the Nb content in the $(Fe_{0.75}B_{0.20}Si_{0.05})_{96}Nb_4$ bulk metallic glass (BMG) has been studied. The glass-forming ability (GFA) is reduced by decreasing the Nb content, but it can be enhanced by replacing partially Fe by Co. Furthermore, the saturation magnetization of the $(Fe_{0.8}Co_{0.2})_{76}B_{18}Si_3Nb_3$ BMG is 1.35 T, being with 13% larger than that of the base alloy $(Fe_{0.75}B_{0.20}Si_{0.05})_{96}Nb_4$. $(Fe_{0.8}Co_{0.2})_{76}B_{18}Si_3Nb_3$ BMG exhibits slightly larger $B_{800}$ (the magnetic flux density at 800 A/m) and smaller core losses (20%-30%) compared with the commercial Fe-6.5 mass% Si steel.