• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.1
• /
• pp.17-23
• /
• 2009

The influence of different forming elements on the local paper structure and the related paper properties was investigated in this study. Specifically, a conventional papermaking foil system and a velocity induced drainage (VID) system were compared. The study involved the analysis of the product samples obtained from the commercial machine trials. The paper samples produced with VID forming systems showed better formation. The deterministic patter in the local structural profile map of the Foil samples indicated the structure of foil samples was more supple after forming process and then easier to be marked by various fabrics such as wet pressing fabric. The higher bulk was observed in the VID samples, which resulted in higher scattering coefficient, lower ZDT strength, and higher bending stiffness.

• Microbiology and Biotechnology Letters
• /
• v.6 no.4
• /
• pp.197-203
• /
• 1978

Voluminous studies have been carried out on the utilization of cellulosic materials as a raw material for the production of sugar or single cell protein. The structural complexity of the substrate generated problems in the research works as well as in the application of the results obtained in the researches. This review outlines the physical ana chemical properties of cellulosic materials obtained from researches in the field other them biology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.11
• /
• pp.693-698
• /
• 2017

In this study, the thermal degradation properties of polyethylene terephthalate film has been examined by the capacitance, Tan ${\delta}$, thermography, FTIR, and SEM results at temperatures of $90{\sim}170^{\circ}C$ and frequencies of 0.3~3,000 kHz. It was found that the capacitance decreased with increasing thermal imaging temperature, probably caused by weakening of chemical bond with increasing temperature. Tan ${\delta}$ decreased upon increasing temperature from $90^{\circ}C$ to $170^{\circ}C$, probably due to the molecular motion of COOH radical or OH radical. The FT-IR measurement reveals that no structural change of the material occurs upon thermal radiation. The SEM measurement shows that the material is stabilized by thermal decomposition with increasing temperature; however, excessive thermal degradation obstructs the stabilization of the material.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.9
• /
• pp.1318-1323
• /
• 2013

Thermal insulation material was prepared by cross-linking chemical reaction of silica aerogel and epoxy resin, which has a high porous and vacant properties. The structural, mechanical, and thermal properties were analyzed in order to verify its application for industrial and electrical applications. The thermal conductivities were changed from 115 mW/mK to 75 mW/mK by reducing the contents of nano-porous silica areogel powders. The compressive loading is also decreased by increasing the contents of silica aerogels by 20 wt% in aerogel/epoxy composites. It is concluded that the formulated composite materials can be applied to building materials, electronics parts, and heavy industries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.11a
• /
• pp.81-84
• /
• 1998

New diagnostic techniques have been tried on the applications of chemical, physical and micro-structural methods because there was a limit to diagnose degradation in Korean Underground Residential Distribution (URD) power cables with the conventional electrical methods. In this study, non-electrical properties were carried out as such. Characterization of interface layer was analyzed by X-ray, characterization of insulator by water tree, degree of crosslinking, shrinkage as well as ${\mu}$ -FTIR, characterization of semiconductive layer by volume resistivity. Electrical properties were also performed by leakage current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.05b
• /
• pp.57-60
• /
• 2001

This study describes the effect of $\tau$ -ray irradiation on the properties of insulation materials for low voltage cables in a nuclear power plant. The radiation effects were characterized by measuring OIT, FTIR, electrical properties of the irradiated specimens. As a result, they showed the decrease of OIT and the increase of chemical structural defects with the increase of $\tau$ -ray amount

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.371-374
• /
• 2003

The corrosion of steel reinforcing bar(re-bar) has been the major cause of the reinforced concrete deterioration. FRP(Fiber-reinforced polymer) reinforcing bar has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. In this study, long-term durability performance of FRP re-bar were evaluated. The mechanical and durability properties of two type of CFRP- and GFRP re-bar were investigated; the FRP re-bars were subjected to alkaline solution, acid solution, salt solution and deionized water. The mechanical and durability properties were investigated by performing tensile and short beam tests. Experimental results confirmed the desirable resistance of FRP re-bar to aggressive chemical environment.

• Journal of the Korea Institute of Building Construction
• /
• v.6 no.1 s.19
• /
• pp.109-115
• /
• 2006

Although the clays were one of the major materials of building constructions, presently, its functions are lesser and the cements take its place as building materials. however, the IAQ problems such as $CO_2$ increase, Rn gas and VOCs occurrence should be imperative from production and construction processes of the cements. This study aims to develop the alternate clay compounds to cements and analyze its properties by experimental tests. For the study, the claymineral of Chungchong-bukdo 10 areas are used. The chemical and structural properties are experimentally analyzed and the pozzolan reaction possibilities of clays are executed.

• Journal of Integrative Natural Science
• /
• v.1 no.3
• /
• pp.250-253
• /
• 2008

New issues arise as to surface characterization, quantification and interface formation. Surface and interface control of CdSe nanocrystal systems, one of the most studied and useful nanostructures. Semiconductor quantum dots (QDs) have been the subject of much interest for both fundamental reseach and technical applications in recent years, due mainly to their strong size dependent properties and excellent chemical processibility. In this dissertation, the synthesis of CdSe quantum dots were synthesized by pyrolysis of high-temperature organometallic reagents. In order to modify the size and quality of quantum dots, we controlled the growth temperature and the relative amount of precursors to be injected into the coordinating solvent. Moreover, an effective surface passivation of monodisperse nanocrystals was achieved by overcoating them with a higher-band-gap material. Synthesized CdSe quantum dots were studied to evaluate the optical, electronic and structural properties using UV-absorption, and photoluminescence measurement.

• The Korean Journal of Ceramics
• /
• v.4 no.3
• /
• pp.231-234
• /
• 1998

LaNiO3 thin films were fabricated on various substrates by spin-coating technique using metal naphthenates as starting materials. Highly-oriented LaNiO3 films with smooth and crack-free surfaces were grown on SrTiO3 (100) and LaAlO3(100) substrates, while films on MgO(100) and Si(100) substrates showed random orientation. In this study, we concluded that lattice-mismatches between LaNiO3 films and substrates used affect film's properties.