• Journal of Korea Water Resources Association
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• v.38 no.12 s.161
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• pp.985-994
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• 2005

We examined problems of the principal component analysis(PCA), which is able to analyze at the low dimensionality as a methodologv to assess hydrologic time series, and introduced the theory and characteristics of independent component analysis(ICA) that can supplement problems of principal component analysis. We also applied the global sea surface temperature(SST) of the Nino region and assessed the correlation between El $\tilde{n}ino$-Southern Oscillation(ENSO) and SST. The results of examining separation-ability of principal components using mixed signals indicate that the independent component analysis is statistically superior compared to that of the principal component analysis. Finally, we assessed correlation between ENSO and global anomaly SST. The independent component analysis was applied to the $5^{\circ}{\times}5^{\circ}$(latitude and longitude) global anomaly SST in the Nino+3.4 region that is the El $\tilde{n}ino$ observation section. We assessed the correlation with the ENSO years. These results of the analysis show that only one independent component($86\%$) was able to represent the entire behavior and was consistent with the main ENSO years. Finally, we carried out independent component analysis for summer seasonal rainfalls at nine stations and could extract ICs to reflect geographical characteristics. The increasing trend has been shown at IC-1 and IC-2 since 1970s.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.768-771
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• 2003

The impulse between launch vehicle and atmosphere can generate a lot of noise and vibration during the process of launching a satellite. Structurally, electronic equipment (KOMPSAT 2, RDU : Remote Drive Unit) of a satellite consists of aluminum case containing PCB (Printed circuit boards). Each PCB has resistors and IC (Integrated circuits). Noise and vibration of wide frequency band are transferred to the inside of fairing, subsequently creating vibration of the electronic equipment of the satellite. In this situation. random vibration can cause malfunctioning of the electronic equipment of the device. Furthermore, when tile frequency of random vibration meets with natural frequency of PCB. fatigue fracture nay occur in the part of solder joint. The launching environment, thus. needs to be carefully considered when designing the electronic equipment of a satellite. In general. the safety of the electronic equipment is supposed to be related to the natural frequency, shapes of mode and dynamic deflection of PCB in the electronic equipment. Structural vibration analysis of PCB and its electronic components can be performed using either FEM(Finite Element Method) or vibration test. In this study. the natural frequency and dynamic deflection of PCB are measured by FEM, aud the safety of the electronic components of PCB is being evaluated according to the results. This study presents a unique method for finite element modeling and analysis of PCB and its electronic components. The results of FEA are verified by vibration test. The method proposed herein may be applicable to various designs from the electronic equipments of a satellite to home electronics.

• Korean Journal of Pharmacognosy
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• v.37 no.1 s.144
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• pp.37-41
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• 2006

This study investigates the chemical components and biological activities in Picrasma quassioides (D.Don) Benn. extracts for the purpose of developing natural pharmaceutical products. The proximate components in Picrasma quassioides (D.Don) Benn. extracts were 81.56% of carbohydrate, 5.80% of crude fat, 7.75% of crude protein, and 2.07% of crude ash. Calcium was the most predominant mineral and followed phosphorus, potassium, sodium, and magnesium, in a decreasing order. The content of the unsaturated fatty acids, such as oleic acid, linoleic acid, and linolenic acid, was find to be higher than those of saturated fatty acids. Water and methanol extract exhibited antioxidative activity with $IC_{50}$ of $128{\mu}g/ml$ and $144{\mu}g/ml$, respectively, suggesting that the extracts are the major biological component in Picrasma quassioides (D.Don) Benn. extracts. The ${\alpha}-glucosidase$ inhibitory activity showed that methanol and water extract were the high inhibitory activity. Considering these results, water extracts of Picrasma quassioides (D/Don) Benn. showed the possibility that they can be used as a new material for natural pharmaceutical products.

• Journal of the Korean Society of Safety
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• v.11 no.1
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• pp.11-15
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• 1996

For the assessment of fracture behaviors of structural components, various fracture mechanics parameters have been applied to date. New approaches to analyze structural fracture performance under elastic-plastic condition have been proposed by the development of testing methods for characterization of material behavior which is defying to the analysis by conventional fracture parameters. In this study, on the assumption that, initiation of crack propagation of a piping materials occurs when the crack tip strain field reaches "the local fracture strain", following two major issues are discussed ; 1) The relationship between the critical value of J-integral($J_{IC}$) and the local fracture strain (${\varepsilon}_c$) in uniaxial tensile test in the region of maximum reduction area was described. 2) To proved the validity of above relations a series of tests were performed under various temperature and on the different piping materials.materials.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.69-77
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• 1999

As the use of automatic handling equipment for sensitive semiconductor devices is rapidly increased, manufacturers of electronic components and equipment need to be more alert to the problem of electrostatic discharges(ESD). Semiconductor devices such as IC, LSI, VLSI become a high density pattern of being more fragile by ESD phenomena. One of the most common causes of electrostatic damage is the direct transfer of electrostatic charge from the human body or a charged material to the electrostatic discharge sensitive devices. Accordingly, characteristics of electrostatic attenuation in domestic semiconductor devices is investigated to evaluate the ESD phenomina in the semiconductors in this paper. The required data are obtained by Static Honestmeter. Also The results in this paper can be used for the prevention of semiconductor failure by ESD.

• Toxicological Research
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• v.11 no.2
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• pp.175-180
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• 1995

We found that bufalln, one of the prominent components of the bufadlenolides in the Chinese medicine chan'su, has the potent inhibitory effects on growth and proliferation of the cultured bovine aortlc endothelial (BAE) and human umbilical vein endothelial (HUVE) cells. All naturally-occuring bufadienolides used in this study inhibited the cell growth in a dose-dependent manner. Particularly, bufalin among the bufadienolides showed the strongest inhibitory activity for the cell growth. The order of growth inhibition by bufadienolides on BAE cells was as follows: bufalin > gamabufotalln > bufotalln > cinobufagin > cinobufotalin > resibufogenin. The $IC_50$ values (50% inhibition of cell growth) of bufalin as determined by XTT assay were the range of 1-10 nM in BAE and HUVE cells. Bufalin exhibited a higher sensitivity towards cultured bovine aortic endothelial cells than human umbilical vein endothelial cells.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.207-212
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• 2005

Prolyl endopeptidase (PEP, EC 3.4.21.26), also referred to as prolyl oligopeptidase, has been suggested to participate in learning and memory processes by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids, and is abundant in brains of amnestic patients. Therefore, compounds possessing PEP inhibitory activity can be good candidate of drug against memory loss. Upon examination for PEP inhibition from traditional medicinal plants having tonic, stimulating, and anti-amnestic effects, Corni Fructus (Cornus officinallis) showed significant PEP inhibition. Ursolic and oleanolic acids, components of Corni Fructus, inhibited PEP with $IC_{50}$ values of $17.2\;{\pm}\;0.5$ and $22.5\;{\pm}\;0.7\;{\mu}M$, respectively.

• 보존과학연구
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• s.29
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• pp.111-124
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• 2008

Gold case which is called sarari container was excavated from Wangheungsaji of Buyeo in October 2007. This case did not contain sarira, but was filled with clear liquid. This study focused on component analysis of the liquid which had filled sarira container, because we didn't know if this case had not originally contained sarira or not. It is said that original sarira can be melted by a some liquid in this case. So, many kinds of samples which are liquid, soil and ground water, was collected from a inner and outer of sarira container, and analyzed using a IC, ICP-MS, GC-MS and SEM-EDS. As a result of analysis, all of the elements composition was identified by general components of soil and ground water. Especially, phosphate which is chemical element to consist of human bone, did not found in this liquid.

• Korean Journal of Pharmacognosy
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• v.35 no.1 s.136
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• pp.80-87
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• 2004

From the $CHCl_3$ and BuOH soluble fractions of the heartwood of Hemiptelea davidii, eleven compounds have been isolated. On the basis of spectral data, they were identified as ${\beta}-sitosterol$ (1), scopoletin (2), kaempferol (3), 4-hydroxybenzoic acid (4), 2-(4-hydroxyphenyl) ethanol (5), aromadendrin (6), scopolin (7), kaempferol 6-C-glucoside (8), aromadendrin 6-C-glucoside (9), taxifolin 6-C-glucoside (10) and quercetin 6-C-glucoside (11), respectively. Among these compounds, compounds 3, 8, 10, and 11 showed potent DPPH radical scavenging activity with $IC_{50}$ values of 11.9, 14.7, 10.3 and $6.2\;{\mu}g/ml$, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.3
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• pp.149-167
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• 2004

Passive components are indispensable in the design and development of microchips for high-frequency applications. Inductors in particular are used frequently in radio frequency (RF) IC's such as low-noise amplifiers and oscillators. This paper gives a broad overview on the on-chip spiral inductors. The design concept and modeling approach of the typical square-shaped spiral inductor are first addressed. This is followed by the discussions of advanced structures for the enhancement of inductor performance. Research works reported in the literature are summarized to aid the understanding of the recent development of such devices.