• Journal of the Korean Society of Tobacco Science
• /
• v.20 no.2
• /
• pp.191-197
• /
• 1998

Discriminant analysis using near infrared spectra derived from Korean Flue-cured(KF) and American Flue-cured(AF), and also Korean Burley(KB) and American Burley(AB) tobacco was done to classify flue-cured and burley tobacco as either grown in Korea or grown in the USA. Samples were scanned in the wavelength of 400 ～ 2500 nm by near infrared analyzer(NIRSystem Co., model 6500). The discrimination equations for flue-cured and burley tobacco were developed using partial least square 2 method in Infrasoft International NIRS 3 software package. KF samples used for the development of the discrimination equations were higher contents of total sugar, crude ash and chlorine, and higher value of leaf density and brightness, but lower contents of nicotine, total nitrogen and ether extracts, and higher value of redness than those of AF samples. KB samples were higher contents of nicotine, crude ash and chlorine, but lower contents of ether extracts and value of brightness than those of AB samples. On 3 dimensional graph drawn with 3 principal component scores calculated with 3 principal component from KF and KB sample spectra, KF sample spectra were significantly different from AF, and also KB sample spectra were significantly different from AB. The discrimination equations of flue-cured and burley were developed with 3 principal component, respectively. The discrimination equations for flue-cured and burley had a standard error of 0.03 and 0.04, and a R2 of 0.88 and 0.84, respectively. The tobacco samples used for the development of discrimination equation were perfectly classified as KF and AF by flue-cured discrimination equation, and also perfectly classified KB and AB by burley discrimination equation, respectively. The correct classification rates of KF and AF samples not used for the development of discrimination equations were 9S % (828 out of 869 samples) and 98 % (98 out of 100 samples) by flue-cured discrimination equations, and KB and AB samples were 94%(345 out of 368 samples) and 100%(42 out of 42 samples) by burley discrimination equations, respectively.

• Journal of the Korean Society of Tobacco Science
• /
• v.27 no.2
• /
• pp.207-211
• /
• 2005

This study was carried out to develop calibration equation of total volatile bases of tobacco leaf using near infrared spectroscopy(NIRS). Burley, imported flue-cured and oriental leaf tobacco samples were collected in 2005 crop year. Calibration equation was developed by modified partial least square method. The standard error of calibration and $R^2$ between traditional analytical method and NIRS analytical method were $0.038\%$, 0.983 for burley and $0.027\%$, 0.986 for imported flue-cured and oriental leaf, respectively. The standard error of performance and $R^2$ between traditional analytical method and NIRS analytical method were $0.048\%$, 0.940 for burley and $0.024\%$, 0.986 for imported flue-cured and oriental leaf, respectively. From these results, the NIRS analytical method seems to be applicable in analyzing total volatile bases of tobacco.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.183-188
• /
• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• Journal of the Korean Society of Tobacco Science
• /
• v.21 no.2
• /
• pp.182-187
• /
• 1999

A bulk curing experiment was carried out to evaluate the effect of air flow reduction in the bulk barn from color fixing stage in the chemical properties of cured leaves, The air flow was controlled by reducing air velocity of a blower from 0.3m/sec to 0.2m/sec using a boltage regulator(Slidac). The bulk curing before color fixing stage was processed in the conventional curing method. Reduction of air circulation in bulk barn did not affected so much on change of the contents of the main chemical components in cured leaved, such as nicotine, total sugar, total nitrogen, petroleum ether extract, and organic acids. Only a slight increase in essential oil contents, such as solanone, damascenone, damascone, $\beta$-ionone, and megastigmatrienone isomer, could be observed in leaves cured in the reduced air flow.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.37 no.6
• /
• pp.406-413
• /
• 1988

This paper is to investigate relationships between tree inception voltage, tree extension or treeing breakdown voltage and physical characteristics changing as parameter of the post-cured conditions of thermo-setting epoxy resin. According to the results in this paper, the optimal tree inception voltage and treeing breakdown voltage of the samples are obtained for the sample post cured for 15 hours at 100 'C. It can be noticed that these results are closely related with the state of interior molecule coupling and three-dimen sional cross-linked of thermo-setting epoxy resin. And tree inception, tree extension and treeing breakdown of the samples are affected significantly on the post-cured conditions and the cooling method after post-cured of thermo-setting epoxy resin. Moreover, the tree extension by ambient temperature are closely related with softening temperature of thermo-setting epoxy resin.

• Journal of Technologic Dentistry
• /
• v.38 no.3
• /
• pp.193-199
• /
• 2016

Purpose: The purpose of this study was to know of photopolymerization effect of self-etch dual-cured resin cement on different transmittance and thickness of zirconia disks. Methods: The two types of transparent and opaque zirconia speciments were prepared. The five speciments of each groups were seperated with 0.5mm and 1.0mm thickness. Degree of conversion(DC) were studied by FT-IR spectroscopy using ATR method before and after irradidaion for 40 sec. Results: The relative DC was showed the higher results of ZS5 as compared with ZS10 (p < 0.05). And OP5 and OP10 were lower results than ZS10 (p < 0.05). Conclusion: The photopolymerization effect of dual-cured resin cement were affected by the transmittance and thickness of zirconia.

• Restorative Dentistry and Endodontics
• /
• v.20 no.2
• /
• pp.827-831
• /
• 1995

This study was designed to etermine the changes in the degree of conversion for composite resins after heat curing following the methods proposed by Lee & Park(1995). 8-mm diameter hole was made in 1mm teflon plate and one of three types of composites (Charisma, Brilllant, Z100) was placed and light cured for 60seconds. The samples were devided into 3 groups according to the placing composites. After light curing, the samples were separated from the moulds. Using this method, 10 samples were prepared in each group; 5 samples from each group were heat cured according to the methods proposed by manutfactures, These samples were then thinned to 50-$70{\mu}m$ and analysed with a Fourier Transform Infrared Spectrometer. Standard baseline technique was used to calculate the degree of conversion. When the samples were light cured, the degrees of conversion in each groups were 47.1 % (charisma), 53.3% (Z100), and 70.1 % (Brilliant). The degree of conversion after heat curing were; 60.1 % (Charisma), 71.1 % (Z100), and 73.3 % (Brillant). Once the samples were heat cured, there were significant increases in degree of conversion.

• Journal of the Korean Society of Tobacco Science
• /
• v.6 no.1
• /
• pp.25-31
• /
• 1984

The volatile aroma components were isolated from Korean flue-cured tobacco (N.C. 2326) by using a vacuum steam distillation method. Individual aroma components were identified by GCIMS and comparison of gas chromatowaphic retention time with those of the authentic samples. Sensory analysis showed that a vacuum steam-distilled product of Flue-cured tobacco had a typical haylike, floral and fruity aroma. Among 62 compounds identified, major compounds included neophytadiene, benzyl alcohol, ethyl acetate, phenyl ethyl alcohol, ethyl alcohol, ethyl formate, acetic acid, solanone, 2-acetyl pyrrole, $\beta$-ionone epoxide, 2, 4-heptadienal (2 isomers), megastigmatrienone (4 isomers), furfural and total amounts of 13 compounds were about 80%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.4
• /
• pp.290-296
• /
• 2011

Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as a resistive gas sensors for the $H_2$ gas detection. Sensor films were fabricated by the air spray method using the multi-walled CNTs dispersion solution on the glass substrates cured with plasma and nitrocellulose. Sensors were characterized by the resistance measurements in the self-fabricated oven in order to find the optimum detection properties for the hydrogen gas molecular. The sensitivity and the linearity of the MWVNT sensors using the glass substrate cured with plasma for the $H_2$ gas concentration of 0.06~0.6 ppm are 0.013~0.097%/sec and 0.131~0.959%FS, respectively. The MWCNT film was excellent in the response for the hydrogen gas moleculars and its reaction speed was very fast, which could be using as hydrogen gas sensor. The resistance of the fabricated sensors decreases when the sensors are exposed to $H_2$ gas.

• Journal of the Korean Society of Tobacco Science
• /
• v.19 no.1
• /
• pp.29-32
• /
• 1997

This study was carried out to develop a new stalk curing of the horizontal hanging method that would reduce the harvesting and curing labor, and improve its quality of cured leaf than the conventional stalk curing method in burley tobacco. The horizontal hanging stalk-curing method designed from 1988 was compared with the conventional method. The horizontal method shortened the curing Period for 7 days and reduced to 0.3%, while it occurred 9.4% in the vertical method. In the horizontal method, the quality of cured leaf improved 9%, but the contents of chemical components and physical properties were similar to those of vertical method. The labor of stalk-cut and loading in curing facility reduced 28% by the horizontal method. In harvesting and curing process, the horizontal method resulted 12% of labor saving as compared with the vertical method. Key words : horizontal hanging stalk-curing method, vertical method, stalk-curing.