• Transactions on Electrical and Electronic Materials
• /
• v.15 no.6
• /
• pp.305-308
• /
• 2014

Organosilyl-modified and star-shaped poly (${\varepsilon}$-caprolactone) (m-PCL) was prepared, and added to polymethylsilsesquioxane (PMSSQ), to make composites. The end groups of m-PCL are chemically similar to PMSSQ, and m-PCL mixed well with PMSSQ in the composite. Porous PMSSQ film was made by further calcination of the composite film at elevated temperature. m-PCL-templated PMSSQ and the as-prepared porous PMSSQ were structurally, optically, and thermally characterized in thin films. The chemical binding of m-PCL and PMSSQ effectively suppressed the phase separation of PMSSQ and m-PCL during the curing process. After calcination at elevated temperature, there remained many pores in the PMSSQ matrix. The refractive indices of the resulting porous PMSSQ thin films decreased with increase of the film porosities, depending on the initial m-PCL loadings.

• Korea-Australia Rheology Journal
• /
• v.12 no.3_4
• /
• pp.157-163
• /
• 2000

We develop a simple model which can describe and explain abnormal stress relaxation of ABS melt for which stress dose not exponentially decay. The relaxation behavior of ABS melt consists of two distinct relaxation modes. One is the relaxation of the matrix phase similar to the case of homopolymer melt. The other is manifested by the collection of butadiene rubber particles, named as the cluster, where the particles are connected through the interaction between grafted SAN and matrix SAN. The second mode of the relaxation is characterized by the relaxation time, which is a function of the average size and the microscopic state of the cluster. Experimental results reveal that it can be represented as the product of the average size of the clusters by a function of internal variable that represents the fraction of strained SAN chains inside the cluster.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.6
• /
• pp.429-433
• /
• 2013

PTFE composites for use of microwave substrate were fabricated by impregnation and heat treatment fabrication with glass fabric. This study shows dielectric properties such as dielectric constant and loss can be controlled by thickness of PTFE composite with change of pressure condition in heating press process. The dielectric constant of the PTFE composites has decreasing tendency as given higher pressure condition. The dielectric loss has similar result too. Especially, the case of the dielectric loss was affected by the condition of pressure at heating press and had the best performance under 3 MPa. In order to see the reason why thickness conditions make different, their microstructures were also observed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1433-1436
• /
• 2007

Using a blue emitting DPVBi material and red dopant DCJTB, WOLEDs with and without green emitter C6 added in ETL or HTL have been fabricated. The chromaticity color index of WOLEDs without C6 depends strongly on the doping concentration. In addition, manipulating thickness of emitting layer is similar effect such as controlling weight concentration of dopant. While the white color of WOLEDs with C6 added in ETL or HTL depend on position of C6. WOLED of three colors added green dye have been shown turn-on voltage of 3.25V, and EL efficiency 3.05cd/A @9V, $8102\;cd/m^2$, CIE coordinates (0.30, 0.32).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.274-275
• /
• 2006

A new thin film materials can be built up at the molecular level, and the relationship between these artificial structures and the properties of materials can be explored. In this paper, in order to confirm the application possibility to the molecular electronic device of the organic materials, we have investigated electro-luminescent (EL) characteristics of organic EL device using $Alq_3$, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.4
• /
• pp.59-66
• /
• 2011

This study was carried out to develop the automation bark peeling process of paper mulberry for making Hanji. Nowadays, almost raw material has been imported from south-east asia for making Hanji. Raw material dependence is very high for Hanji-making by low productivity in korea. This study is focused on the resolution for problem of bark peeling automation. Water and sand jet of compressed air was possible bark peeling for black bast fiber. The effect of removing black bast fiber increased the longer the steaming time. Also using drum of bark peeling showed that results under temperature $80^{\circ}C$ and Rpm 50/min were best bark peeling and separating bast fiber from stem. The contents of holocellulose, lignin, ethanol-benzene extractives, and ash were 91.63~95.55%, 1.4~2.0%, 1.12~1.65%, and 1.4~4.3%, respectively. Chemical characteristics are similar between imported raw-material with drum bark.

• Transactions on Electrical and Electronic Materials
• /
• v.8 no.3
• /
• pp.121-124
• /
• 2007

The $Zn_2SiO_4:Mn$ phosphors were prepared using polymer matrix technique in order to improve the performance of green emitting phosphors for plasma display panel(PDP). $Zn_2SiO_4:Mn$ phosphor exhibits a strong green emission around 520-530 nm. The emission intensity and particle size of powders were controlled by sintering temperature and raw material composition. The zinc silicate $Zn_2SiO_4:Mn$ single phase were obtained at lower temperature than prepared by solid-state reaction method. PL luminance of $Zn_2SiO_4:Mn$ phosphor was similar to the commercial material.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.177-182
• /
• 1998

In this study, We compare material properties of Self-compacting concrete using Korean Belite cement with Japanese. Self-compacting concrete consolidates densely by virtue of its own weight at the location where concrete compaction cannot be carried out. Material properties of Korean and Japanese Belite cement are very similar but compatibility with superplasticizer and viscosity agent are some different. Before the batch mix, the compatibility must be checked as fresh concrete properties. For the concrete test results, Korean Beilite cement is suitable to product High performance concrete.

• Journal of Veterinary Clinics
• /
• v.11 no.1
• /
• pp.377-381
• /
• 1994

This study was performed to investigate the usefulness of the radiopaque material as a disintegration test of enteric coated capsules radiologically. The results obtained were as follows; 1. The times that the enteric coated capsules passed the pylorus(GI transition times) were the first 150 minute and the last 390 minutes. Therefore, the GI transition times largely differ from each animal and each enteric coated capsule. 2. The disintegration times of enteric coated capsules were similar in vitro test and in vitro test. 3. The disintegration test of enteric coated capsules using Barium sulfate, radiopaque material for the gastrointestinal track, was useful to check the time pass through the pylorus and the time enteric coated capsules were disintegration.

• Korean Journal of Veterinary Research
• /
• v.35 no.2
• /
• pp.391-398
• /
• 1995

This study was carried to investigate the usefulness of the radiopaque material as the GI transition and disintegration test of enteric coated capsules radiologically. The obtained results were as follows; 1. The GI transition times that the enteric coated capsules pass through the pylorus were that the time of the first capsule was 210 minutes and the time of the last capsules was more than 300 minutes. Therefore, the GI transition times largely differ from each animal and each enteric coated capsule. 2. The disintegration times of enteric coated capsules were similar in vitro test and in vivo test. 3. The GI transition and disintegration test of enteric coated capsules using barium sulfate, radiopaque material for the gastrointestinal track, was useful to investigate the times that the capsules passed through the pylorus and disintegrated in intestinal track.