• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.44-52
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• 2012

This study examined the effects of the drying rate, temperature distribution and vapor pressure on the surface checks occurring during the air circulating oven-drying of hollowed short Japanese larch (Larix Kaemferi C.) round posts treated with coating (CO) and vapor-dam (VD). The hollowed round posts could be dried from the green condition to a moisture content of approximately 8% in 72 to 144 hours. The temperature in the hole was higher than that inside of wood for Control and VD specimens, while VD specimen showed opposite distribution. The vapor pressure inside the wood was higher than that in the hole for the CO and VD specimens during hole drying stage. There were few surface checks found in the specimens but the number increased in order the of CO, VD and Control specimens.

• Korean Journal of Materials Research
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• v.23 no.12
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• pp.737-744
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• 2013

We demonstrated size control of Au nanoparticles by heat treatment and their use as a catalyst for single-walled carbon nanotube (SWNTs) growth with narrow size distribution. We used uniformly sized Au nanoparticles from commercial Au colloid, and intentionally decreased their size through heat treatment at 800 oC under atmospheric Ar ambient. ST-cut quartz wafers were used as growth substrates to achieve parallel alignment of the SWNTs and to investigate the size relationship between Au nanoparticles and SWNTs. After the SWNTs were grown via chemical vapor deposition using methane gas, it was found that a high degree of horizontal alignment can be obtained when the particle density is low enough to produce individual SWNTs. The diameter of the Au nanoparticles gradually decreased from 3.8 to 2.9 nm, and the mean diameter of the SWNTs also changed from 1.6 to 1.2 nm for without and 60 min heat treatment, respectively. Raman results reconfirmed that the prolonged heat treatment of nanoparticles yields thinner tubes with narrower size distribution. This work demonstrated that heat treatment can be a straightforward and reliable method to control the size of catalytic nanoparticles and SWNT diameter.

• Advanced Composite Materials
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• v.18 no.3
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• pp.221-232
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• 2009

The allylamine plasma treatment is used to modify the surface properties of vapor grown carbon fibers (VGCF). It is to improve the interfacial bonding between the VGCF and epoxy matrix. The allylamine plasma process was performed by batch process in a vacuum chamber, using gas injection followed by plasma discharge for the durations of 20, 40 and 60 min. The interdependence of mechanical properties on the VGCF contents, treatment time and interfacial bonding between VGCF/ep was investigated. The interfacial bonding between VGCF and epoxy matrix was observed by scanning electron microscopy (SEM) micrographs of nanocomposites fracture surfaces. The changes in the mechanical properties of VGCF/ep, such as the tensile modulus and strength were discussed. The mechanical properties of allylamine plasma treated (AAPT) VGCF/ep were compared with those of raw VGCF/ep. The tensile strength and modulus of allyamine plasma treated VGCF40 (40 min treatment)/ep demonstrated a higher value than those of other samples. The mechanical properties were increased with the allyamine plasma treatment due to the improved adhesion at VGCF/ep interface. The modification of the carbon nanofibers surface was observed by transmission electron microscopy (TEM). SEM micrographs showed an excellent dispersion of VGCF in epoxy matrix by ultrasonic method.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.103-109
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• 1998

We studied on the decoloring effect of viscose rayon by vapor type ozone processing using ozone's strong oxidation. When ozone is generated, it becomes high concentration in vapor state, but in the insolving process with water, there are a lot of lose of ozone. As a result, a study using ozone in vapor-high concentration state is needed. So, in this paper, vapor type ozone processing is used unlike previous ozone treatment method-an aqueous solution method-to get a good effect from shortening the processing time. When vapor type ozone processing was directly treated to fabrics, high concentration ozone was generated then in a short time oxidized a dye existed in fabrics and finally decolored it. As vapor type ozone did not directly response to an organic dye, viscose rayon's decolorization was to be studied by changing pick up ratio(60%, 50%, 40%, 30%, 20%) using water as a medium. When pick up ratio of water was 40%, fabric's whiteness was improved but tensile strength and elongation were reduced. So 60 minutes was assumed as the most adjust time to minimize the reduction of fabric's tensile strength and elongation moreover of maximize the improvement of whiteness.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.384.2-384.2
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• 2014

We investigated the electrical and structural properties of chemical vapor deposition (CVD)-grown graphene and post treated by O2 plasma. For the patterning of graphene, the plasma technology is generally used and essential for etching of graphene. But, the cautious O2 plasma treatments are required to avoid the damage in graphene edge which can be the harmful effects on the device performance. To analyze the effects of plasma treatment on structural properties of graphene, the change of surface morphology of graphene are measured by scanning electron microscope and atomic force microscope before and after plasma treatment. In addition, the binding energy of carbon and oxygen are measured through to X-ray photoelectron spectroscopy. After plasma treatment, the severe changes of surface morphology and binding energy of carbon and oxygen were observed which effects on the change of sheet resistance. Finally, to analyze of graphene characteristics, we measured the Raman spectroscopy. The measured results showed that the plasma treatment makes the upward of D-peak and downward of G'-peak by elevated power of plasma.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.60-68
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• 2000

Biofiltration is an environmentally-sound technology for elimination of VOCs and odorous compound from low-concentration, high-volume waste gas streams because of its simplicity and cost-effectiveness. It can be appled to the treatment of gases from publicly owned treatment works, composting facilities, landfill sites, and soil vapor extraction systems. The ability to design an effective biofilter system involves a combination of fundamental biofilter knowledge, practical experience, and bench- and pilot-scale testing. The objective of this paper was to review principle, design parameters, operational conditions, case studies, and economy of biofiltration through literature.

• Textile Coloration and Finishing
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• v.26 no.1
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• pp.13-21
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• 2014

The object of this research is to perform the basic research for the development of selectively permeable membrane fabrics which is suitable for korean military in sense of embattlement. As a key factor of selectively permeable membrane fabrics which is suitable for korean military, this study selected the best PVA thickness and membrane selection for DMMP protection, pre-treatment method for conformational stability of face fabric and water/oil repellent process condition. Especially as the PVA coating thickness of the fabrics increase, peneration of DMMP decrease including water vapor permeation is lower. This study shows how physical features and permeability of chemical agents can be influenced by pre-treatment methods, the selection of selectively permeable membrane, the thickness of PVA etc. Results showed that outer shell / PVA / e-PTFE materials possessed performance with superior water vapor permeation (Over $3,000g/m^2/day$) and protective capability against DMMP vapor ($0.6{\mu}g/cm^2{\cdot}16hr$).

• Journal of Powder Materials
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• v.11 no.2
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• pp.124-129
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• 2004

Nanosized WC and WC-Co powders were synthesised by chemical vapor condensation(CVC) process using the pyrolysis of tungsten hexacarbonyl(W(CO)$_6$) and cobalt octacarbonyl(Co$_2$(CO)$_8$). The microstructural changes and phase evolution of the CVC powders during post heat-treatment were studied using the XRD, FE-SEM, TEM, and ICP-MS. CVC powders were consisted of the loosely agglomerated sub-stoichimetric WC$_{1-x}$ and the long-chain Co nanopowders. The sub-stochiometric CVC WC and WC-Co powders were carburized using the mixture gas of CH$_4$-H$_2$ in the temperature range of 730-85$0^{\circ}C$. Carbon content of CVC powder controlled by the gas phase carburization at 85$0^{\circ}C$ was well matched with the theoretical carbon sioichiometry of WC, 6.13 wt％. During the gas phase carburization, the particle size of WC increased from 20 nm to 40 nm and the long chain structure of Co powders disappeared.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.697-702
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• 2001

Effects of ammonia treatment on the morphologies of the catalytic metal films and carbon nanotubes subsequently synthesized via a thermal chemical vapor deposition method were investigated. An optimally controlled thermo-chemical process of ammonia treatment gave rise to a morphology of a dense distribution of vertically aligned carbon nanotubes. $NH_3$ treatment is a crucial key process to obtain vertically aligned carbon nanotubes. However, it was realized by a simple $NH_3$ treatment during synthesis at temperatures of $800-900^{\circ}C$ without any extra process. The structure and morphology of carbon nanotubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.763-769
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• 2005

Ferroelectric $ReMnO_3$(Re:Ho, Er) thin films were deposited on Si(100) substrate by Metal-Organic Chemical Vapor Deposition (MOCVD). Crystallinity and electric properties of $ReMnO_3$(Re:Ho, Er) thin films were investigated as a function of thermal heat treatment process, CHP (Conventional Heat-treatment Process) and RTP (Rapid Thermal Process). $ReMnO_3$(Re:Ho, Er) thin films prepared by RTP showed higher c-axis preferred orientation and homogeneous surface roughness than those prepared by CHP. The remnant polarization of ferroelectric hysteresis loop of $ReMnO_3$(Re:Ho, Er) thin films was strongly dependent on the c­axis preferred orientation of hexagonal single phase, and the leakage current characteristics of thin films were dependent on the homogeneity of grain size as well as surface roughness of thin films.