• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.3.1-3.1
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• 2009

Nanotechnology has beenrapidly evolved from passive nanostructures where nanostructures with steadystructures and functions often used as parts of a product to activenanostructures which change their properties during use. Startingaround 2010, it is anticipated that researchers will cultivate expertise withsystems of nanostructures, directing large numbers of intricate components tospecified needs. One dimensional (1-D) nanostructures suchas nanowires and nanotubes are extremely attractive building blocks for nextgeneration devices because of their high surface to volume ratio and uniquesize dependent properties. In addition, their extremely high aspectratio offers researchers the potentials to build axial or radialheterostructures to integrate multiple functionality from intrinsic propertiesof the material or through interfacial phenomena. Spatialmanipulation and the ability to assemble and position nanostuructures in acontrolled matter so they are registered to define spaces is also a criticalstep toward scalable integration in high density nanodevices. In thispresentation, a generalized template directed electrodeposition with ancillaryassembly, contact will be presented to synthesize axial and radialheterostructures in cost-effective matter and these individual nanostructureswill be applied to spintronics, gas and biological sensors and thermoelectrics.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.14-14
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• 2009

High frequency electromagnetic(EM) waves are increasingly being applied in industries because of saturationat lower frequency bands as a result of huge demand. However, electromagneticinterference (EMI) has become a serious problem, and as a result, highfrequency EM absorbers are now being extensively studied. Also, recentdevelopments in absorber technology have focused on producing absorbers thatare thin, flexible, and strong. Hence, one-dimension ferrous nano-materials area potential research field, because of their interesting electronic andmagnetic properties. Commercially, EM wave absorbing products are made ofcomposites, which blend the insulating polymer with magnetic fillers. Inparticular, the shape of the magnetic fillers, such flaky, acicular, or fibrousmagnetic metal particles, rather than spherical, is essential for synthesizingthin and lightweight EM wave absorbers with higher permeability. High aspectratio materials exhibit a higher permeability value and therefore betterabsorption of the EM wave, because of electromagnetic anisotropy. Nanowires areusually fabricated by drawing, template synthesis, phase separation, selfassembly, and electrospinning with a thermal treatment and reduction process.Producing nanowires by the electrospinning method involves a conventionalsol-gel process that is simple, unique, and cost-effective. In thispresentation, Magnetic nanowire and dielectric materials coated magneticnanowire with a high aspect ratio were successfully synthesized by theelectrospinning process with heat treatment and reduction. In addition toestimating the EM wave absorption ability of the synthesized magnetic anddielectric materials coated magnetic nanowire with a network analyzer, weinvestigated the possibility of using these nanowires as high-frequency EM waveabsorbers. Furthermore, a wide variety of topics will be discussed such as thetransparent conducting nanowire and semiconducting nanowire/tube with theelectrospinning process.

• Composites Research
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• v.27 no.2
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• pp.37-41
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• 2014

Fiber reinforced composite materials have outstanding specific strength and specific stiffness. So the use of composite materials increases in various kinds of industrial fields including sports goods such as bicycles. Composite materials are used to make structural parts with various kinds of shapes. Specially, rectangular composite tubes are used to make a few of composite bicycle frames, but there has been a few of research on this issue. Rectangular composite tubes are designed to have appropriate radius of curvature and endure bending and torsional loads. In this research, nine kinds of rectangular composite tubes having aspect ratios 1:1, 1:1.5, 1:2 and radius of curvatures R5, R10, R15 were fabricated. The carbon fiber reinforced composite material was used to make tubes having same cross sectional areas. The stacking sequence of tubes is $[0/90/{\pm}45]s$. Experimental evaluation was accomplished to apply bending and torsional load to the tubes. Experimental results show that bending and torsional characteristics depend on radius of curvature and aspect ratio of rectangular composite tubes.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.139-148
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• 1995

The test results from three one fourth scale models using high strength Reinforced Concrete $f_x=704\;kg/cm^2,\;f_y=5.830\;kg/cm^2$ are presented. Such specimens are considered to represent the critical 3 storics of 60-story tall building of a structural wall system in area of high seismicity respectively. They are tested under inplane vertical and horizontal loading. The main varlable is the level of axial stress. The amounts of vertical and horizontal reinforcement are identical for the three walls testcd. The cross-section of all walls is barbell shape. The aspectratio($h_w/I_w$) of test specimen is 1.8. The aim of the study is to investigate the effects of levels of applied axial stresses on the inelastic behavior of high-strength R /C tall walls. Experimental results of high strength R /C tall walls subjected to axial load and simulated sels rnic loading show that it is possible to insure a ductlle dominant performance by promotmg flex ural yielding of vertical reinforcement and that axial stresses within $O.21f_x$ causes an increase in horizontal load-carrying capacity, initial secant st~ffness characteristics, but an decrease in displacement ductility. energy dissipation index and work damage index of high strength K /C tall walls