• Journal of Sensor Science and Technology
• /
• v.7 no.2
• /
• pp.117-123
• /
• 1998

The $In_{2}O_{3}$ thin films were fabricated on a alumina substrate by spin-coating method and the gas sensing properties were tested. The coating solution was synthesized by the mixing of aqueous solution of $In(OH)_{3}$ and acetic acid, and ammonium carboxymethyl cellulose as a binder. The $In_{2}O_{3}$ thin films between 71 and 210nm thick were obtained by spin-coating between 1 and 7 times followed by drying at $110^{\circ}C$ and calcining at $600^{\circ}C$. The films consisted of a dense stack of tiny $In_{2}O_{3}$ particles between 23 and 27nm in diameter and covered well large grains of the alumina substrate. Then film thickness was well controlled by the number of spin-coating. The fabricated $In_{2}O_{3}$ films showed high sensitivity and very fast response property to CO and $H_{2}$.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.12a
• /
• pp.104-105
• /
• 2007

• Journal of Information Display
• /
• v.6 no.2
• /
• pp.19-24
• /
• 2005

The density controlled carbon nanotubes (CNTs) are grown on the iron acetate nanoparticles by using the freeze-dry method. The iron-acetate [Fe(II)$(CH_3COO)_2$] solution is used to prepare the catalytic iron nanoparticles. The density of CNTs is controlled in order to enhance the field emission process. Furthermore, the patterning of the iron nanoparticle catalyst-layer for the fabrication of electronic devices is simply achieved by using alkaline solution, TMAH (tetramethylammonium hydroxide). We applied this patterning process of catalyst layer to form the electron emitter with under-gate type triode structure.

• Korean Journal of Applied Biomechanics
• /
• v.22 no.1
• /
• pp.75-82
• /
• 2012

The purpose of this study was to suggest the proper shaft and head fitting methods of the golf club to increase the flight distance of the golf ball. Rotations per minute of the golf ball(RPM), ratio of Ball speed to club head speed(T-Ratio) and launch angle right after impact(LA), which are directly related to ball flight distance, were measured using Spectra with shutter speed of 1/1000sec at the constant head speed of 95mph which was controlled by robot golf swing machine. In order to investigate the effect of club shaft to the 3 selected variables, 10 shafts were used to make ten test clubs with one controlled club head which is the most commonly used by golf players. To measure the effect of the club head to the 3 selected variables, 6 golf club heads which are most commonly used by golfers were selected to make 6 test clubs with a controlled shaft which is one of the best known by players. The shafts and the heads were identified by statistical analysis to increase or decrease the RPM, T-ratio and LA. A proper fitting method of the selected shafts and the club head was suggested to increase the ball flight distance in golf.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.385-385
• /
• 2012

A two terminal N+/P/N+ junction device to replace the conventional selective transistor was studied as a bilateral switching device for spin transfer torque (STT) MRAM based on 3D device simulation. An N+/P/N+ junction structure with $30{\times}30nm$ area requires bi-directional current flow enough to write a data by a drain induced barrier lowering (DIBL) under a reverse bias at N+/P (or P/N+ junction), and high current on/off ratio of 106. The SiGe materials are widely used in hetero-junction bipolar transistors, bipolar compensation metal-oxide semiconductors (BiCMOS) since the band gap of SiGe materials can be controlled by changing the fraction and the strain epilayers, and the drift mobility is increased with the increasing Ge content. In this work, N+/P/N+ SiGe material based junction provides that drive current is increased from 40 to $130{\mu}A$ by increased Ge content from 10~80%. When Ge content is about 20%, the drive current density of SiGe device substantially increased to 2~3 times better than Si-based junction device in case of 28 nm P length, which is sufficient current to operation of STT-MRAM.

• The Journal of Natural Sciences
• /
• v.14 no.2
• /
• pp.1-14
• /
• 2004

The observation of the various swing parameters and its effect on golfer swing are tatally analyzed. The golf ball impact and flies away, therefore it must be controlled bofore ball impact. The purpose of this paper is that the cause of hook and slice are found and the posture of swing is corrected. The trajectory after ball impact is on the $\Delta$-plane, which is consisted of the normal vector on club face and the swing velocity vector of club head including the initial celocity and the spin axis after ball imfact. In order to correct the miss shot in golf swing, this paper is is shown that the theoretical review and study is discussed to use the D-plane and $\Delta$-plane.

• Journal of the Korean Magnetics Society
• /
• v.23 no.3
• /
• pp.98-103
• /
• 2013

The magnetic easy axis of the ferromagnetic layer for the dual-type GMR-SV (giant magnetoresistance-spin valve) having NiFe/Cu/NiFe/IrMn/NiFe/Cu/NiFe multuilayer structure controlled by the post annealing treatment. The magnetoresistive curves of a dual-type IrMn based GMR-SV depending on the direction of the magnetic easy axis of the free and the pinned layers are measured by the different angles for the applied fields. By investigating the switching process of magnetization for an arbitrary measuring direction, the optimum annealing temperature having a steady and isotropy magnetic sensitivity of 2.0 %/Oe was $105^{\circ}C$. This result suggests that the in-plane orthogonal magnetization for the dual-type GMR-SV film can be used by a high sensitive biosensor.

• Membrane Journal
• /
• v.14 no.1
• /
• pp.57-65
• /
• 2004

The effect of porous support layer resistance and PDMS (polydimethylsiloxane) coating thickness on ethylene/nitrogen separation of composite membranes was studied with the model of Pinnau and Wijmans〔1〕. To control the support resistance (or permeance), PES porous membranes were prepared by phase inversion process with various PES/NMP dope concentrations. The thickness of selective PDMS top layer was controlled by using a spin coater. Its cross-section and coating thickness were observed by scanning electron microscope (SEM). Pure gas permeation test was done with ethylene and nitrogen, respectively. The experimental result for olefin/nitrogen separation process matched well with theoretical result from the model used. The result shows that optimization between PDMS coating thickness and support resistance is important to get PDMS composite membranes with best performance.

• Korean Chemical Engineering Research
• /
• v.46 no.4
• /
• pp.777-782
• /
• 2008

Using ultrasonic-induced polymerization of pyrrole, mesoporous $TiO_2$ thin film with polypyrrole nanoparticles was prepared. Polypyrrole nanoparticles were ultrasonically synthesized in the mother solution of mesoporous $TiO_2$ before spin-coating. The polypyrrole particles were well dispersed in the solution. After spin-coating and calcinations process, the nanocomposite films have well-organized pore channels without pore-collapse, and polypyrrole nanoparticles are well dispersed in mesoporous $TiO_2$ matrix. The pore size and light absorbance of the mesoporous nanocomposite thin films were controlled by using different template materials, and by using different amount of pyrrole monomer, respectively.

• Macromolecular Research
• /
• v.15 no.4
• /
• pp.324-329
• /
• 2007

An octa-functional alkoxyamine initiator, with the 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO) free radical, was synthesized based on resorcinarene, with its efficiency to initiate the nitroxide-mediated free radical copolymerization of styrene and methyl methacrylate (MMA) described. A difunctional analogue of this initiator was also synthesized, using resorcinol as the core molecule. The structures of the resulting initiators were confirmed by homolysis studies based on electron spin resonance spectroscopy and molecular modeling. The polymerization behavior and characteristics of the polymers obtained using these two initiators were also compared. Well-defined star-shaped and linear random copolymers, with low polydispersities and controlled molecular weights, were prepared. The efficiencies of these initiators towards copolymerization, as well as the parameters permitting the formation of well-defined polymers, were also investigated. The reactivity ratios were $r_a=0.42(a=styrene)\;and\;r_b=0.33(b=MMA)$ for the octa-functional initiator system and $r_a=0.45\;and\;r_b=0.39$ for the difunctional initiator system.