• Textile Coloration and Finishing
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• v.8 no.3
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• pp.8-15
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• 1996

Three pieces of cotton fabrics used for this study were exhumed in the Mt.Moo Deung near Kwang Ju in 1965. The fabrics were remains of Jang Heung Lim Si-the nephew's wife of General Kim Deok Ryeong. It was reported that Jang Heung Lim Si died in 1615. The cotton fabrics were classified into three, A, B and C, according to their color. The fabric A was inherent color of cotton, the fabric B was that of light brown and the fabric C was that of dark brown. The physical and chemical characteristics of the cotton fabrics were examined. In the meantime the construction of cotton fabrics and traditional dyeing of Yi dynasty were studied through various records. The results were as follows: 1. According to electromicroscopic examination, the lumen in the cotton fiber had not been developed enough, therefore the quality of cotton at that time was supposed to be not so excellent. 2. The results of chemical analysis indicated that: (1) While the copper number of the cotton fabric A was similar to that of bleached cotton, that of the fabric C was extremely high. (2) The amount of methylene blue absorption was much more than that of normal cotton. (3) The content of cellulose was less than that of normal cotton. (4) The degree of polymerization was less than that of normal cotton. From the results mentioned above, it was concluded that the cotton fabrics were oxidized slowly in the closed lime coffin for a long period of time. From this process of oxidization and deterioration, the degree of polymerization was decreased through depolymerization, and carboxyl groups were produced by the oxidization at reducing end groups. 3. It was confirmed that the cotton fabric C was dyed by the juice of immature persimmon. Thus, it was inferred that the large amount of copper number of cotton fabric C was derived from phenolic OH groups of tannins having high reducing properties in persimmon.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.31-37
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• 2000

Metal matrix composites(MMCs) are rapidly becoming one of the strongest candidates for structural materials for many high temperature application. Among the high temperature environment, thermal shock is known to cause significant degradation in most MMC system. Therefore, the nondestructive evaluation on thermal shock damage behavior of SiC/A16061 composite has been carried out using ultrasonic surface and SH-waves. For this study, Sic fiber reinforced metal matrix composite specimens fabricated by a squeeze casting technique were thermally cycled in the temperature range 25~$400^{\circ}C$ up to 1000 cycles. Three point bend test was conducted to investigate the effect of thermal shock damage on mechanical properties. The relationship between thermal shock damage behavior and the change of ultrasonic velocity and attenuation were discussed by considering SEM observation of fracture surface.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.65-71
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• 1999

The effects of mask materials and etching solutions on the dimensional accuracy of V-groove were studied for the alignment between optoelectronic devices and optical fibers in optical packaging. PECVD nitride, LPCVD nitride, or thermal oxide($SiO_2$) was used as a mask material. The anisotropic etching solution was KOH(40wt%) or the mixture of KOH and IPA. LPCVB nitride has the best etching selectivity and thermal oxide was etched most rapidly in KOH(40wt%) at $85^{\circ}C$ among the mask materials studied here. The V-groove size enlarged than the designed value. This phenomenon was due to the undercutting benearth the mask layer from the etching toward Si (111) plane. The etch rate of (111) plane wart 0.034 - 0.037 $\mu\textrm{m}$/min in KOH(40wt%). This rate was almost same regardless of mask materials. When IPA added to KOH(40wt%), the etch rate of (100) plane and (111) plane decreased, but etching ratio of (100) to (111) plane increased. Consequently, the undercutting phenomenon due to etching toward (111) plane decreased and the size of V-groove could be controlled more accurately.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.132-136
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• 2012

Kenaf (Hibiscus cannabinus) is an annual herbaceous plant of the family Malvacease that has been planted in tropical Africa and Asia region for more than 4000 years and use as source of fiber, energy and feed stock. In this study, the physiological characters and chemical compositions of kenaf mutant variety "Jangdae" developed using gamma irradiation at the Korea Atomic Energy Research Institute (KAERI) were compared with three genetic resources (Auxu, C12, and C14-DRS). Jangdae showed the highest productivity growth rates in fresh yield, dry weight (DW) yield (leaf and stem), node number, and stem thickness. Especially, leaf DW yield of Jangdae was 1.6-3.1 times higher than that of three genetic resources. Also, stem DW yield of Jangdae was 1.6-2.1 times higher than that of three genetic resources. In the analysis of chemical composition, Jangdae showed 16.9% of crude protein content that was 0.86-0.94 times lower than three cultivars. However, Jangdae showed the highest neutral detergent fiber (NDF) contents in leaf (32.5%) and stem (75.2%). Also, acid detergent fiber (ADF) contents of stem and leaf in Jangdae were 64.4% and 33.9%, respectively. Total polyphenol and total flavonoid contents were 22.1 mg/g and 7.4 mg/g in Jangdae. Based on these results, Jangdae would have the potential to become a successful forage crop.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.464-464
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• 2010

A few years ago, for maintaining high stability and production yield of production equipment in a semiconductor fab, on-line monitoring of wafers is required, so that semiconductor manufacturers are investigating a software based process controlling scheme known as virtual metrology (VM). As semiconductor technology develops, the cost of fabrication tool/facility has reached its budget limit, and reducing metrology cost can obviously help to keep semiconductor manufacturing cost. By virtue of prediction, VM enables wafer-level control (or even down to site level), reduces within-lot variability, and increases process capability, $C_{pk}$. In this research, we have practiced VM on $SiO_2$ etch rate with optical emission spectroscopy(OES) data acquired in-situ while the process parameters are simultaneously correlated. To build process model of $SiO_2$ via, we first performed a series of etch runs according to the statistically designed experiment, called design of experiments (DOE). OES data are automatically logged with etch rate, and some OES spectra that correlated with $SiO_2$ etch rate is selected. Once the feature of OES data is selected, the preprocessed OES spectra is then used for in-situ sensor based VM modeling. ICP-RIE using 葰.56MHz, manufactured by Plasmart, Ltd. is employed in this experiment, and single fiber-optic attached for in-situ OES data acquisition. Before applying statistical feature selection, empirical feature selection of OES data is initially performed in order not to fall in a statistical misleading, which causes from random noise or large variation of insignificantly correlated responses with process itself. The accuracy of the proposed VM is still need to be developed in order to successfully replace the existing metrology, but it is no doubt that VM can support engineering decision of "go or not go" in the consecutive processing step.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.64-64
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• 2000

Since its discovery in 1991, the carbon nanotube has attracted much attention all over the world; and several method have been developed to synthesize carbon nanotubes. According to theoretical calculations, carbon nanotubes have many unique properties, such as high mechanical strength, capillary properties, and remarkable electronical conductivity, all of which suggest a wide range of potential applications in the future. Here we report the synthesis in the catalytic decomposition of acetylene at ~65 $0^{\circ}C$ over Ni deposited on SiO2, For the catalyst preparation, Ni was deposited to the thickness of 100-300A using effusion cell. Different approaches using porous materials and HF or NH3 treated samples have been tried for synthesis of carbon nanotubes. It is decisive step for synthesis of carbon nanotubes to form a round Ni particles. We show that the formation of round Ni particles by heat treatment without any pre-treatment such as chemical etching and observe the similar size of Ni particles and carbon nanotubes. Carbon nanotubes were synthesized by chemial vapour deposition ushin C2H2 gas for source material on Ni coated Si substrate. Ni film gaving 20~90nm thickness was changed into Ni particles with 30~90nm diameter. Heat treatment of Ni fim is a crucial role for the growth of carbon nanotube, High-resolution transmission electron microscopy images show that they are multi-walled nanotube. Raman spectrum shows its peak at 1349cm-1(D band) is much weaker than that at 1573cm-1(G band). We believe that carbon nanotubes contains much less defects. Long carbon nanotubes with length more than several $\mu$m and the carbon particles with round shape were obtained by CVD at ~$650^{\circ}C$ on the Ni droplets. SEM micrograph nanotubes was identified by SEM. Finally, we performed TEM anaylsis on the caron nanotubes to determine whether or not these film structures are truly caron nanotubes, as opposed to carbon fiber-like structures.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.315-321
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• 1999

Metal matrix composites have been extensively studied because of their excellent characteristics for structural application. $Al_2O_3$ and SiC have been used as a common reinforcement owing to their good mechanical properties. However the manufacturing cost of these ceramic reinforcement is expensive, so the use of the composites has been restricted to special purposes. In this study, we tested the application possibility as a reinforcement of $Al_2O_3$-TiC powder synthesized by SHS(Self-propagating High-temperature Synthesis) process to Al alloy matrix composite. Also, $Al_2O_3$ short fibers were added with the synthesized powders in order to apply to the Al matrix hybrid composites. Squeeze infiltration casting process was used to make the composite with 25vol% of reinforcement. Microstructure and crystal structure were examined by SEM, OM and XRD, also the mechanical properties were studied by the compressive test and wear test.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.187-194
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• 1986

Present stadies were carried out to obtain fundermental data for effective management of the soils by investigating the physicochemical characteristics rubber fiber, humification grade and bearing power of peats and muck which were included in Geongdeog series, and Gimje series in Honam area. The results abtained were as follows; 1. Humification grade of peats were about 23, while that of muck soils was about 45-71 and those were higher in Gimje series than Bongnam series. 2. The organic tiers which humification grade was higher were high pH, bulk density, and contents of K, $P_2O_5$, B.S and while were low OM, T-C, T-N, Na, $SiO_2$ and rubbed fiber. 3. In peats and mucks, bulk density, pH, contents of T-N $P_2O_5$ and ash were negatively correlated with rubbed fiber and OM, CEC, T-C, PAC, C/N, C/P were positively correlated with one, while these physicochemical characteristics were oppositely correlated with humification grade. 4. Cone bearing power of each soil tiers was low in every Geongdeog series which had the thick organic tiers and showed poorly drainage and it was the highest in Gimje series which was similar to in organic soils because of its thin organic tiers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.89-97
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• 2015

In this study, dissolution characteristics of 60% LiBr aqueous solution for Miscanthus sinensis holocellulose in accordance with heating time and characteristics of regenerated films were analyzed. Miscanthus sinensis holocellulose was made by peracetic acid method. During the dissolution of 60% LiBr solution for the holocellulose, the dissolution was started from the tip of the cellulose fiber after about 7 minutes, and proceeded as it swollen like a balloon. A lot of Si was identified by analyzing hollocellulose regenerated film through SEM/EDS. Cross section of regenerated film as dissolution time till 40 minutes of dissolution showed multilayered structure and fiber orientation. But after 40 minutes, multilayered structure and fiber orientation was not observed. The crystal structure of the holecellulose was transformed cellulose I into cellulose II. Therefore, dissolution for 20 minutes with 60% LiBr solution in the condition of $190^{\circ}C$ hot plate was shown as an optimum condition to manufacture the holocellulose regenerated film.

• Clean Technology
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• v.15 no.1
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• pp.16-22
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• 2009

In this study, a fiber reinforced plastic (FRP) pipe with superior wear resistance was developed to replace the fly ash pipe of cast iron. Wear test was performed with various combinations of SiC filler and resin materials of unsaturated polyester, vinylester, epoxy, and phenol. Test results of ASTM D4060 showed the optimal combinations of resin, filler size, and resin/filler ratios. Test results of comparison between FRP and cast iron showed the possibility to replace cast iron pipe with the FRP pipe. Field test executed to compare the wear resistance between cast iron pipe and developed FRP pipe showed the superiority of the FRP pipe.