• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.245-248
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• 1998

Porous carbon fiber composites (CFCs) having variable specific surface area ranging 35~1150 $\m^2$/g were reacted to produce silicon carbide fiber composites with SiO vapor generated from a mixture of Si and $SiO_2$ at 1673 K for 2 h under vacuum. Part of SiO vapor generated during conversion process condensed on to the converted fiber surface as amorphous silica. Chemical analysis of the converted CFCs resulting from reaction showed that the products contained 27~90% silicon carbide, 7~18% amorphous silica and 3~63% unreacted carbon, and the composition depended on the specific carbide, 7~18% amorphous silica and 3~63% unreacted carbon, and the composition depended on the specific surface area of CFCs. CFC of higher specific surface area yielded higher degree of conversion of carbon to silicon and conversion products of lower mechanical strength due to occurrence of cracks in the converted caron fiber. As the conversion of carbon to silicon carbide proceeded, pore size of converted CFCs increased as a result of growth of silicon carbide crystallites, which is also linked to the crack formation in the converted fiber.

• 한국문화재보존과학회:학술대회논문집
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• 2004.10a
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• pp.109-114
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• 2004

The purpose of this study lies in analyzing the characteristics of the carbonized textile fabrics and to know the carbonizing mechanism. Samples were Jiyo excavated from the grave of Mrs. Hansan Lee as the wife of Jinju Kang at Daeduk-gu, Daejon, and black fragements assumed as of the outside material of cotton skirt and black dusts collected out of Jikryung for official dress. The composition and status of the fiber were clarified by means of Microscopic FT-IR and both cross sectioanl and side parts of the fiber were observed using the technique of scanning electron microscopy(SEM). Finally EDS analysis was carried out to qualitatively analyze inorganic ingredients contained in the carbonized fiber. As a result of FT-IR measurement, characteristic peak was very strong around $1625cm^{-1}$ and could be found even between 2500 and $2300cm^{-1}$ because of a high-molecule pigmental substance, melanine. When SEM photography was applied to the fractions, the tissues were identified as silk fiborine through the observation of their side and cross sectional parts. SEM-EDS measurement indicated that both the cotton skirt and Jikryung for official dress contained a high proportion of inorganic substances such as Si, Ca suggesting the existence of silicide and calcium carbonate.

• Journal of the Korean Wood Science and Technology
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• v.31 no.3
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• pp.1-10
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• 2003

Shredded waste newspapers, waste acrylic raw fibers, and urea-formaldehyde (UF) adhesives, at 10% by weight on raw material, were used to produce recycled waste paper-waste acrylic raw fiber composite boards in laboratory scale experiments. The physical and mechanical properties of fire retardant treated recycled waste paper-waste acrylic raw fiber composite boards were examined to investigate the possibility of using the composites as internal finishing materials with specific gravities of 0.8 and 1.0, containing 5, 10, 20, and 30(wt.%) of waste acrylic raw fiber and 10, 15, 20, and 25(wt.%) of fire retardant (inorganic chemical, FR-7^®) using the fabricating method used by commercial fiberboard manufacturers. The bending modulus of rupture increased as board density increased, decreased as waste acrylic raw fiber content increased, and also decreased as the fire retardant content increased. Mechanical properties were a little inferior to medium density fiberboard (MDF) or hardboard (HB), but significantly superior to gypsum board (GB) and insulation board (IB). The incombustibility of the fire retardant treated composite board increased on increasing the fire retardant content. The study shows that there is a possibility that composites made of recycled waste paper and waste acrylic raw fiber can be use as fire retardant internal finishing materials.

• Korean Journal of Optics and Photonics
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• v.20 no.4
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• pp.201-206
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• 2009

In this study, we have fabricated a fiber-optic radiation sensor for detection of tritium using inorganic scintillators and optical fibers. We have tested various kinds of inorganic scintillators such as $Gd_2O_2S$ : Tb, $Y_3Al_5O_{12}$ : Ce, and CsI : Tl to select the most effective sensor tip. In addition, we have measured the scintillating lights using a photomultiplier tube as a function of distance between sensor tips to the source with the different activities of hydride tritium. The final results are compared with those which are obtained using a surface activity monitor.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.823-831
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• 1996

At the ratio [$H_2O$]/[TEOS]=1.7, the silica sol was synthesized by partial hydrolysis in the presence of acid catalyst. After stabilizing the silica sol by trimethylsilylation, the molecular weight and viscosity of the sol obtained at various reaction times were examined to determine a best spinnability of the sol. Gel fibers were prepared from the sol solution after removing solvent in the solution, and the gel fibers were heated at $1,000^{\circ}C$. The prepared silica fibers were in the shape of circular cross-section and their tensile strength and $SiO_2$ purity were $83{\pm}20kg/mm^2$ and about 99.997%, respectively.

• Journal of Fashion Business
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• v.13 no.3
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• pp.136-148
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• 2009

The phenomenon of the shrinkage of silk fibers induced by inorganic salts including LiBr, $Ca(NO_3){_2}$, and $CaCl_2$, has been studied up to the present as one of the finishing methods of silk. It is expected that the shrinkage phenomenon may greatly contribute to the realization of the high sensibility of silk fibers. Especially the shrinkage enables the expression of three-dimensional appearance of silk fabrics along with the improvements in dimensional stability, resilience in stretching, and comfort. Numerous theoretical studies on the contraction phenomenon by $Ca(NO_3){_2}$ have been conducted so far. These studies have focused mostly on the silk fibers. It is difficult to find studies on silk fabrics. The negative aspects of the finishing are such as strength drop, yellowish discoloration, and fiber damage. These should also be considered as well as the positive aspects. In this study, the phenomenon of salt shrinkage is diversely reviewed by applying $Ca(NO_3){_2}$ solution for the silk fabrics as objects. The changes in the air permeability, thickness, and color were investigated with focus on the shrinkage of the silk fabrics according to the changes in treatment conditions. Some findings from this study are as follows: Within short period of time at the initiation of salt shrinkage, the salt shrinkage proceeds effectively. In the case of concentration of 47.4%, or 46.3% of $Ca(NO_3){_2}$ solution, appropriate treatment time seems to be 20seconds, or $2{\sim}8$minutes, respectively. Excessive shrinkage is obtained when lower liquor ratio is adopted. As a result, the condition is acting extremely disadvantageously against the thickness and yellow discoloration aspects.

• Ceramist
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• v.10 no.3
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• pp.55-66
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• 2007

Infrared Scanning Near-field Optical Microscopy (IR-SNOM) is an extremely powerful analytical instrument since it combines IR spectroscopy's high chemical specificity with SNOM's high spatial resolution. In order to do this in the infrared, specialty chalcogenide glass fibers were fabricated and their ends tapered to generate SNOM probes. The fiber tips were installed in a modified near field microscope and both inorganic and biological samples illuminated with the tunable output from a free-electron laser located at Vanderbilt University. Both topographical and IR spectral images were simultaneously recorded with a resolution of ${\sim}50\;nm$ and ${\sim}100\;nm$, respectively. Unique spectroscopic features were identified in all samples, with spectral images exhibiting resolutions of up to ${\lambda}/60$, or at least 30 times better than the diffraction limited lens-based microscopes. We believe that IR-SNOM can provide a very powerful insight into some of the most important bio-medical research topics.

• Textile Coloration and Finishing
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• v.14 no.4
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• pp.208-213
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• 2002

In dyeing PET/Spandex blends with disperse dyes, many disperse dyes are absorbed more readily into Spandex than PET. Inorganic/organic(I/O) values can characterize the affinity of disperse dyes for Spandex and PET fibers. As I/O values of disperse dyes approach that of Spandex, the dye uptake in Spandex increases. On the contrary, the disperse dyes of higher I/O values are absorbed more into PET than Spandex. The dye uptake in PET increases with increasing I/O values of disperse dyes. As I/O values of disperse dyes increase, the rate of dyeing become slower in the dyeing of PET/Spandex blends. Hence, the affinity and the compatibility of disperse dyes in PET/Spandex blends dyeing can be evaluated with I/O value.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.83-89
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• 1999

Bast fibers of paper mulberry ( Broussonetia Kazinoki Sieb) were cooked with a weak alkaline salt, potassium carbonate which has been known as a major inorganic component of the traditional lye, and its cooking characteristics were investigated . The bast fiber was easily cooked by potassium carbonate. The pulp yield was rapidly decreased up to 20-30 mol of potassium carbonate, but the Kappa number was slowly decreased with increasing of potassium carbonate. The potassium carbonate pulps were easily defibered at low cooking chemical charge of 25mm on and high pulp yield of about 80%. These results were confirmed that pectin was easily removed during the potassium carbonate cooking. In contrast, when sodium carbonate was used as a cooling agent, the bast fiber was only partially defibered. Thus, sodium carbonate was a less effective cooling chemical of the bast fiber. The results of this experiment indicated that potassium carbonate could not only be used as a good cooling agent of bast fiber, but also as an alternative agent of sodium hydroxide.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.227-233
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• 2011