• Journal of the Korean Society of Clothing and Textiles
• /
• v.37 no.6
• /
• pp.764-771
• /
• 2013

The metal component of Chinese and Korean traditional gold thread was analyzed nondestructively using P-XRF and classified morphologically. In the nondestructive analysis of 22 Chinese and Korean artifacts, there were 10 gold threads made up of Au in China and 7 in Korea; in addition, there were 4 silver threads made up of Ag in Korea and 1 copper thread made up of Cu in China. In the morphological classification, 7 gilt paper strips were confirmed in China and Korea and 4 wrapped threads were identified in China and Korea. Zn, Sn and Fe (minor components of the threads) were detected. These components were assumed to be transferred from the metal found in burial goods.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.30 no.4
• /
• pp.42-48
• /
• 1998

The bacterial cellulose(BC) has many unique properties that are potentially and commercially beneficial. In order to enhance inherently inferior physical property of chemithermomechanical pulp(CTMP) sheet, chemical pulp has been used widely. Bacterial cellulose also has an enhanced sheet strength because of its unique physical and morphological features. This study was carried out to inverstigate the effect of BC addition on physical properties of CTMP sheets. The effect of BC addition on its optical properties was also discussed. The apparent density, internal bond strength, Young's modulus, tensile strength and folding endurance of CTMP sheet are increasing with increase of BC contents. This strength increase would be attributed to the increase of relative bonding sites among pulp fibers by addition of BC which has microfibrillar structure with very high specific surface areas. There were not so significant changes in opacity of CTMP sheet upto 20% addition level of BC, while over 40% addition, the opacity gradually decreased and levelled off. Porosity is decreased with addition of BC. This decrease would be attributed to densification of sheet by fine and filamentous structure of BC fibers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.29 no.4
• /
• pp.53-63
• /
• 1997

Most cellulose resources come from the higher plants, but bacteria also synthesize same cellulose as in plants. Many scientists have been widely studied on the bacterial cellulose, the process development, manufacturing, even marketing of cellulose fibers. The bacterial celluloses are very different in its physical and morphological structures. These fibers have many unique properties that are potentially and commercially beneficial. The fine fibers can produce a smooth paper with enchanced its strength property. But there gave been few reports on the mechanical properties of the processing of bacterial cellulose into structural materials. This study were performed to elucidate the mechanical properties of sheets prepared from bacterial cellulose. Also reinforcing effect of bacterial cellulose on the conventional pulp paper as well as surface structures by scanning electron microscopy were discussed. Paper made from bacterial cellulose is 10 times much stronger than ordinary chemical pulp sheet, and the mixing of bacterial cellulose has a remarkable reinforcing effect on the papers. Mechanical strengthes were increased with the increase of bacterial cellulose content in the sheet. This strength increase corresponds to the increasing water retention value and sheet density with the increase of bacterial cellulose content. Scanning electron micrographs were shown that fine microfibrills of bacterial celluloses covered on the surfaces of hardwood pulp fibers, and enhanced sheet strength by its intimate fiber bonding.

• Journal of Korea Foundry Society
• /
• v.28 no.2
• /
• pp.79-84
• /
• 2008

Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

• KSBB Journal
• /
• v.16 no.4
• /
• pp.370-375
• /
• 2001

For the production of new exo-biopolymers from microorganisms, an exe-biopolymer producing bacterial strain was isolated from the composter used in composting of organic wastes. Bacteriological properties of this strain and physicochemical properties of producing exo-biopolymer were investigated. The isolated strain was identified as Enterobacter sp. through its morphological, cultural and physiological characteristics. The results of color reactions, CPC (cetyl pyridinium chloride) precipitation and infra red absorption spectral analysis indicated that this exo-biopolymer was presumed as an acidic polysaccharide with uronic acid. This polysaccharide was identified as hetero-polysaccharide consisting of galactose, mannose and galacturonic acid by gas chromatography, and the molecular weight of exopolysaccharide purified by gel chromatography were about 370,000 daltons. The polysaccharide solutions(0.50-2.0%, w/v) exhibited non-Newtonian flow behavior with pseudoplastic property and showed the ability of gel formation at above 1.5% (w/v) of polysaccharide concentration.

• Polymer(Korea)
• /
• v.37 no.4
• /
• pp.513-517
• /
• 2013

A novel conductive composite thin film was prepared for the first time by hybridization between polybenzoxazine (PBZ) having high heat resistance property and conductive graphene. Mechanically robust conductive graphene/PBZ composite thin films could effectively be prepared by a simple thermal treatment, which simultaneously induces reduction of graphene oxide (GO) and crosslinking reaction of benzoxazine monomer. Graphene sheets seem to be uniformly dispersed up to 3 wt% graphene content in the composite thin film as shown in the results of chemical/crystal structural and morphological analyses. This efficient route for making graphene/PBZ composite thin film would provide simultaneous improvement of mechanical property as well as electrical conductivity.

• Journal of Energy Engineering
• /
• v.7 no.1
• /
• pp.146-156
• /
• 1998

Fly ash produced in coal combustion is a fine-grained material consisting mostly of spherical, glassy, and porous particles. A physical, morphological, and chemical characteristic of fly ash has been analyzed. This study may contribute to the data base of domestic fly ash, the improvement of combustion efficiency, ash recycling and ash collection in the electrostatic precipitator. The physical property of fly ash is determined using a particle counter for the measurement of ash size distribution and gravimeter. Morphological characteristic of fly ash is performed using a scanning electron micrograph and an optical microscope. The chemical components of fly ash are determined using an inductively coupled plasma emission spectrometry (ICP). The distribution of fly ash size was ranged from 15 to 25 $\mu$m in mass median diameter. Exposure conditions of flue gas temperature and duration within the combustion zone of the boiler played an important role on the morphological properties of the fly ash such as shape, relative opacity, coloration, cenosphere and plerosphere. The spherical fly ash might be generated at the condition of complete combustion. The size of fly ash was found to be increased the with particle-particle interaction of agglomeration and coagulation. Fly ash consisted of $SiO_2\;Al_2O_3\;and\;Fe_2O_3$ with 85% and carbon with 3~10% of total mass.

• Korean Chemical Engineering Research
• /
• v.49 no.4
• /
• pp.438-442
• /
• 2011

Mechanical and morphological properties of poly(acrylonitrile-butadiene-styrene) (ABS) and poly(lactic acid) (PLA) blends containing compatibilizers were investigated. Poly(styrene-acrylonitrile)-g-maleic anhydride) (SAN-g-MAH), poly(ethylene-co-octene) rubber-maleic anhydride (EOR-MAH) and poly(ethylene-co-glycidyl methacrylate) (EGMA) were used as compatibilizers. Mechanical properties such as tensile, flexural and impact strengths of ABS/PLA (80/20, wt%) blends were found to be increased when the SAN-g-MAH, EOR-MAH and EGMA were used. The maximum values for mechanical properties of the ABS/PLA (80/20) blend were observed when SAN-g-MAH was used as a compatibilizer at the concentration of 3 phr. From morphological studies of the ABS/PLA (80/20) blends, PLA droplet size was decreased by the addition of the compatibilizers used in this study. From the results of mechanical and morphological properties of the ABS/PLA (80/20) blends, SAN-g-MAH (3 phr) was found to be the most effective compatibilizer among the compatibilizers used in this study.

• Fibers and Polymers
• /
• v.2 no.3
• /
• pp.129-134
• /
• 2001

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) (50/50, mole/mole) [PECPT] was synthesized and blended with polycarbonate (PC). LC properties of PECPT and thermal, morphological, and rheological behaviors of the PECPT/PC blend were studied. PECPT showed the nematic LC phase and much longer relaxation time than poly(ethylene terephthalate) (PET). The apparent melt viscosity of PECPT was one third of that of FET. An abrupt torque change was observed during the blending process due to the orientation of LC domains. For the blends containing 10~30 wt% of PECPT, the complex viscosities were higher than that of PC. As PECPT content increases above 40 wt%, shear thinning was observed. The lowest complex viscosity was obtained at 40~50 wt%. Transesterification of PECPT and PC was confirmed by the selective chemical degradation of carbonate groups in PC.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.7 s.250
• /
• pp.794-799
• /
• 2006

In recent years, the use of natural fiber as reinforcement in polymer composites to replace synthetic fiber such as glass fiber is receiving increasing attention. Because of increasing usage according to the high demand, the cost of thermoplastic has increased rapidly over the past decades. We used a thermoplastic polymer(polypropylene) as the matrix and a lignocellulosic material(rice-husk flour) as the reinforcement filler to prepare a particle-reinforced composite to examine the possibility of using lignocellulosic material as reinforcement filler and to determine data of test results for physical, mechanical and morphological properties of the composite according to the reinforcement filler content in respect to thermoplastic polymer, In this study, PLA/PP rice-husk fiber-reinforced thermoplastic composites that made by the hot press molding method according to appropriate manufacturing process was evaluated as mechanical properties.