• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.3
• /
• pp.292-300
• /
• 2006

In order to improve energy efficiency in the dilute trichloroethylene removal using the nonthermal plasma process, the barrier discharge treatment combined with manganese dioxide was experimentally studied. Reaction kinetics in this process was studied on the basis of final byproducts distribution. Decomposition efficiency was improved to about $99\;\%$ at the specific energy of 40 J/L with passing through manganese dioxide. C=C ${\pi}$ bond cleavage of TCE substances gave DCAC, which has the single bond of C-C through oxidation reaction during the barrier discharge plasma treatment. Those DCAC were broken easily in the subsequent catalytic reaction due to the weak bonding energy about $3{\sim}4\;eV$ compared with the double bonding energy in TCE molecules. Oxidation byproducts of DCAC and TCAA from TCE decomposition are generated from the barrier discharge plasma treatment and catalytic surface chemical reaction, respectively. Complete oxidation of TCE into COx is required to about 400 J/L, but $CO_2$ selectivity remains about $60\;\%$.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1988-1990
• /
• 1996

In this work, we have grown or evaporated thermal oxide and E-beam oxide on the (100) oriented n-type silicon wafers, respectively and they were directly bonded with another silicon wafer after hydrophilization using solutions of three types of $HNO_3$, $H_{2}SO_{4}$ and $NH_{4}OH$. Changes of average surface roughness after hydrophilizations of the single crystalline silicon wafer, thermal oxide and E-beam evaporated silicon oxide were studied using atomic force microscope. Bonding interfaces of the bonded pairs were inspected using scanning electron microscope. Void and non-contact area of the bonded pairs were also inspected using infrared transmission microscope.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.3
• /
• pp.265-271
• /
• 2008

TCP(Tape Carrier Package), COG (Chip On Glass), COF(Chip On Film) are three methods for connecting LDI(LCD Driver IC) with LCD panels. Especially COF is growing its portion of market place because of low cost and fine pitch correspondence. But COF has a problem of the lead broken failure in LCD module process and the usage of customer. During PCB (Printed Circuit Board) bonding process, the mismatch of the coefficient of thermal expansion between PCB and D-IC makes stress-concentration in COF lead, and also D-IC bending process during module assembly process makes the level of stress in COF lead higher. As an affecting factors of lead-broken failure, the effects of SR(Solder Resister) coating on the COF lead, surface roughness and grain size of COF lead, PI(Polyimide) film thickness, lead width and the ACF(Anisotropic Conductive Film) overlap were studied, The optimization of these affecting manufacturing processes and materials were suggested and verified to prevent the lead-broken failure.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.121-126
• /
• 2000

Metal/Ceramic structures have many attractive properties, with great potential for applications that demand high stiffness, as well as chemical and biological stability, thermal and electrical insulation. They are currently in use for mechanical and thermal protection in cutting tool and engine parts. With all their great advantage, ceramics suffer from one major problem they are brittle, and are especially susceptible to cracking from surface contacts. Delamination at the interfaces with adjacent layers is a particularly disturbing problem, and can cause premature failure of a composite system. so determination of adhesive properties of coating is one of the most important problems for the extension of the use of coated materials. In this work, mechanical characteristics of Interface of ceramic/Metal composites are evaluated by means of hardness test, indentation test apparent interfacial toughness and bonding strength test. The interface indentation test provides a relation between the applied load(P) and the length of the crack(a) created at the interface between the coating and the substrate.

• Journal of Power System Engineering
• /
• v.9 no.4
• /
• pp.137-142
• /
• 2005

The effects of temperature and initial crack length on impact fracture behavior of side plate material of 35 ton class FRP ship, which are composed by glass fiber and unsaturated polyester resin, were investigated. Impact fracture toughness of GF/PE composites displayed maximum value when the temperature of specimen is room temperature and $50^{\circ}C$, and with decrease in temperature of specimen, impact fracture toughness decreased. Impact fracture energy of GF/EP composites decreased with increase in initial crack length of specimen, and this value decreased rapidly when the temperature of specimen is lowest, $-25^{\circ}C$,. It is believed that sensitivity of notch on impact fracture energy were increased with decrease in temperature of specimen. As the GF/EP composites exposed in low temperature, impact fracture toughness of composites decreased gradually owing to the decrease of interface bonding strength caused by difference of thermal expansion coefficient between the glass fiber/polyester resin. Further, decrease of interface bonding strength of composites with decrease in specimen temperature was ascertained by SEM photograph of impact fracture surface.

• Journal of Sensor Science and Technology
• /
• v.18 no.4
• /
• pp.307-310
• /
• 2009

This paper describes the formation of porous 3C-SiC by anodization. 3C-SiC thin films were deposited on p-type Si(100) substrates by APCVD using HMDS(Hexamethyildisilane: $Si_2(CH_3)_6$). UV-LED(380 nm) was used as a light source. The surface morphology was observed by SEM and the pore size was increased with increase of current density. Pore diameter of 70 $\sim$ 90 nm was achieved at 7.1 mA/cm$^2$ current density and 90 sec anodization time. FT-IR was conducted for chemical bonding of thin film and porous 3C-SiC. The Si-H bonding was observed in porous 3C-SiC around wavenumber 2100 cm$^{-1}$. PL shows the band gap enegry of thin film(2.5 eV) and porous 3C-SiC(2.7 eV).

• Journal of Welding and Joining
• /
• v.19 no.3
• /
• pp.311-316
• /
• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.3
• /
• pp.11-20
• /
• 2011

The conditions to which pulp fibers are exposed during paper production, converting, storage, use, and recycling can induce various changes in fiber morphology, surface characteristics, and suitability for paper production by recycled fibers. Most of those changes can be described by hornification. Paper has highly hygroscopic properties which affect dimensional change by relative humidity variation of surrounding condition. The purpose of this study was to investigate the dimensional stability, moisture contents and dip elongation of handsheets at different relative humidity conditions of recycled kraft pulp and BCTMP. By using recycled fibers, dimensional stability was increased because hygroscopic properties of fibers decreased with repeated recycling treatment. Dip elongation of recycled pulp was higher than that of virgin pulp because of its weak fiber-to-fiber bonding. By recycling pulp, the relative bonded area was decreased because fiber could not swell more than virgin pulp. Dimensional stability largely depended on the equilibrium moisture contents of paper, the fiber-to-fiber bonding strength, and the relative bonded area.

• Journal of Welding and Joining
• /
• v.9 no.4
• /
• pp.17-27
• /
• 1991

The direct brazing technology which could be used for the simplification of brazing process and the improvement of brazed joint quality was studied with $Al_2O_3$ and stainless steels. The brazing of $Al_2O_3$ to STS304 or STS430 was performed under different brazing conditions such as brazing filler metal, temperature, heating rate and brazing time. Microstructural observation and chemical analysis be SEM/EPAM were carried out to verify the quality of brazed joints. 4-point bending strength of brazed joints was also measured to find the optimal brazing conditions. The results showed that, in brazing of $Al_2O_3$, the mixed oxide layer resulted from the reaction between Ti in filler metal and oxide layer on the material surface to be brazed was found to be bery important for the joint quality. The width of oxide layer varied with the brazing conditions such as brazing time, heating rate and chemical composition of filler metals. The strength of brazed joints was more affected by the type of materials and their thermal properties than by brazing heat cycle.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2357-2362
• /
• 2008

LHP is different from a conventional heat pipes in design and heat and fluid flow passages. The situations of the former is much complex than the latter. In LHPs, evaporation occurs at the contact interface between the heating plate and the porous wick, so some micro channels machined at the contact interface serve to let the vapor flow out of the evaporator. This complexity of contact geometry was known to cause a high resistance to heat flow. The present work was to study the problem of heat passage across the contact surface for LHPs and determine those values contact resistance. For two cases of contact structures, the thermal contact resistances were examined experimentally, one being obtained through mechanical contact under pressure and the other through sintered bonding. Nickel powder wick and copper plate were used for specimens. The result showed that a substantial reduction of contact resistance of an order of degree could be obtainable by sintered bonding.