• YAKHAK HOEJI
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• v.57 no.4
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• pp.272-281
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• 2013

In this study, we developed and validated the HPLC method using the isolated components from Erycibae caulis. Their structures were elucidated by spectroscopic methods including UV, $^1H$-NMR, $^{13}C$-NMR, FAB-Mass and ESI-Mass as Compound 1 (crypto-chlorogenic acid), Compound 2 (scopolin), Compound 3 (neochlorogenic acid) and Compound 4 (3,4-di-O-caffeoylquinic acid). Major three compounds and scopoletin were decided as representative components of Erycibae caulis. We established HPLC analytical method by using the representative components and 20 commercial samples which were collected considering to various cultivated area. The HPLC fingerprinting was successfully achieved with an AKZO NOBEL Kromasil 100-5C18 column. The mobile phase consisted of 0.5% acetic acid in water (A) and methanol (B) using gradient method of 85(A) to 50(A) for 35min. The fingerprints of chromatograms were recorded at an optimized wavelength of 330 nm. This developed analytical method was validated with specificity, selectivity, accuracy and precision. And it is suggested that scopolin, scopoletin, neochlorogenic acid, 3,4-di-O-caffeoylquinic acid were more than 0.162%, 0.133%, 0.057%, 0.044%, respectively. In addition, principal component analysis (PCA) was performed on the analytical data of 20 different Erycibae caulis samples in order to classify samples collected from different regions. We hope that this assay can be readily utilized as quality control method for Erycibae caulis.

• Journal of Plant Biology
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• v.37 no.4
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• pp.441-444
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• 1994

From immature seed of Phaseolus vulgaris L., a novel phytosteryl glucoside was isolated. Strong ion peaks at m/z 613 $[M+Na}^{+},\;696\;[M+Matrix]^{+}$ in positive F AB- MS and at m/z 589 $[M-1]^{-}$ in negative F AB- MS indicated the molecular weight of the compound is 590. Four hundred MHz $^IH-NMR$ analysis revealed that the compound canys a 24-hydroxy-24-vinyl-cholesterol (saringosterol) as an aglycone and a ${\beta}-D-glucopyranose$. Four hundred MHz $^IH-NMR$ analysis of the acetate derivate of the compound revealed that hydroxyls at C-1' in glucose moeity and at C-3 in aglycone have been condensed. Therefore, the phytosteryl glucoside was characterized to be $3-0-{\beta}-D-glucopyranosyl-24-hydroxy-24-vinyl-cholesterol$ (saringosteryl glucoside). This is the first demonstration for the presence of saringosterol in higher plants. Also this is the first identification of saringosteryl glucoside in natural materials.erials.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.278-291
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• 2008

For the semiconductor manufacturing processes, so many vacuum systems are needed with large power consumption for vacuum pumps. Semiconductor device manufacturing makers are concerned about the power consumption and have to address this because it is related with the environmental issues. So many solutions including the design and the control of them by vacuum pump manufacturers to reduce the power consumption of vacuum pump are proposed. However, how to use vacuum pumps by users and the conditions for vacuum pump to be used are also very important to reduce the power consumption. In this article, how to reduce the power consumption of vacuum pumps is explained briefly and what the impact of semiconductor technology trend on the power consumption is considered very briefly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.145-148
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• 2003

Recently, the recycle of CMP (chemical mechanical polishing) slurries have been positively considered in order to reduce the high COO (cost of ownership) and COC (cost of consumables) in CMP process. Among the composition of slurries (buffer solution, bulk solution, abrasive particle, oxidizer, inhibitor, suspension, antifoaming agent, dispersion agent), the abrasive particles are one of the most important components. Especially, the abrasive particles of slurry are needed in order to achieve a good removal rate. However, the cost of abrasives, is still very high. In this paper, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size and hardness. Also, we annealed the collected abrasive powders to promote the mechanical strength of reduced abrasion force. Finally, we compared the CMP characteristics between self-developed KOH-based silica abrasive slurry and original slury, As our experimental results, we obtained the comparable removal rate and good planarity with commercial products. Consequently, we can expect the saving of high cost slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.33-36
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• 2003

Tungsten is widely used as a plug for the multi-level interconnection structures. However, due to the poor adhesive properties of tungsten (W) on $SiO_2$ layer, the Ti/TiN barrier layer is usually deposited onto $SiO_2$ for increasing adhesion ability with W film. Generally, for the W-CMP (chemical mechanical polishing) process, the passivation layer on the tungsten surface during CMP plays an important role. In this paper, the effect of oxidants controlling the polishing selectivity of W/Ti/TiN layer were investigated. The alumina $(Al_2O_3)$ abrasive containing slurry with 5 % $H_2O_2$ as the oxidizer, was studied. As our preliminary experimental results, very low removal rates were observed for the case of no-oxidant slurry. This low removal rate is only due to the mechanical abrasive force. However, for Ti and TiN with 5 % $H_2O_2$ oxidizer, different removal rate was observed. The removal mechanism of Ti during CMP is mainly due to mechanical abrasive, whereas for TiN, it is due to the formation of metastable soluble peroxide complex.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.45-48
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• 2003

The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on tungsten passivation layer in order to obtain higher removal rate (RR) and very low non-uniformity (NU%) during W-CMP process. In this paper, we investigated the effects of oxidizer on W-CMP process with three different kinds of oxidizers, such as $H_2O_2$, $Fe(NO_3)_3$, and $KIO_3$. In order to compare the removal rate and non-uniformity of three oxidizers, we used alumina-based slurry of pH 4. According to the CMP tests, three oxidizers showed different removal mechanism on tungsten surface. Also, the microstructures of surface layer by AFM image were greatly influenced by the slurry chemical, composition of oxidizers. The difference in removal rate and roughness of tungsten surface are believed to caused by modification in the mechanical behavior of $Al_2O_3$ abrasive particles in CMP slurry. Our stabilized slurries can be used a guideline and promising method for improved W-CMP process.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.182-188
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• 2011

Polysilazane and polymethylsilazane based precursor films were deposited on Si-substrate by spin-coating, subsequently annealed at $150{\sim}850^{\circ}C$, and characterized. Structural analysis, shrink, compositional change, etch rate, and gap-filling were observed. Annealing the precursor films led to formation of spin-on dielectric films. C-containing precursor films showed that less loss of N, H, and C while less gain of O than that of C-free precursor films at $400^{\circ}C$, but more loss of N, H, and C while more gain of O at $850^{\circ}C$. Thus polysilazane based precursor films exhibited less reduction in thickness of 14.5% than silazane based one of 15.6% at $400^{\circ}C$ but more 37.4% than 19.4% at $850^{\circ}C$. FTIR indicated that C induced smaller amount of Si-O bond, non-uniform property, and lower resistance to chemical etching.

• 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.

• Journal of the Korean Society for Library and Information Science
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• v.51 no.1
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• pp.289-306
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• 2017

This study explores the concepts and programs of 'makerspaces' at public libraries. It examines the extended and sustainable service outreach strategies of 14 Korean public libraries whose makerspaces were identified as "infinite imagination spaces." Through interviews with staff members, the study identifies the needs, effects, limitations, and future direction of makerspaces. The study also evaluates the development, types, funding sources, and outcomes of makerspaces in public libraries through related literature reviews and case studies. The study's findings suggest that strategies with stable and varied funding, staffing, and training are crucial to fostering makerspaces that not only become communal gathering spots, but also become gateways to technological tinkering that 'make' spaces for community archives.

• Journal of the Korean Wood Science and Technology
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• v.49 no.3
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• pp.267-273
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• 2021

Camellia nut shell was collected, dried at room temperature and ground to get fine powder. The powder was extracted three times with 95% EtOH, combined, evaporated, and then freeze dried. The crude powder was dissolved in H₂O and then sequentially fractionated with n-hexane, CH₂Cl₂, EtOAc and n-BuOH. A part of EtOAc fraction was chromatographed on a silica gel and on a Sephadex LH-20 columns using MeOH, aqueous MeOH, EtOAc-n-hexane and EtOH-n-hexane to isolate gallotannins. Three gallotannins, 1,2-di-O-galloyl-β-D-glucopyranoside (2), 1,2,6-tri-O-galloyl-β-D-glucopyranoside (3) and 1,2,3,6-tetra-O-galloyl-β-D-glucopyranoside (4), including gallic acid (1), were isolated and elucidated by NMR and Mass spectroscopies. Although nothing new, these gallotannins were first reported from the nut shell extractives of camellia tree (Camellia oleifera C. Abel). This study was to investigate the chemical constituents, especially hydrolysable tannins, of nut shell extractives of Camellia oleifera and to provide basic information for the future chemical utilization of this species.