• BMB Reports
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• v.30 no.3
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• pp.188-193
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• 1997

Membrane lipid peroxidation processes yield products that may react with DNA to cause mutations. Lipid hydroperoxides from linoleic acid in the presence of transition metal ions caused strand breaks in plasmid DNA. DNA damage induced by reactive aldehydes known to be produced by decomposition of lipid hydroperoxides, such as 4-hydroxynonenal or rnalondialdehyde, was repaired by endonucleases and exonuclease III which resulted in the increase of single strand breaks in DNA. Lipid hydroperoxides as well as malondialdehyde and 4-hydroxynonenal also caused mutations in the pUC18 lacZ' gene when measured as a loss of ${\alpha}-cornplementation$. In conclusion. the lipid peroxidation could be an important intermediary event in DNA damage and mutation by oxidative stress.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.55-59
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• 2004

Recently, life cycle and lead-time of products have been shortened with the demand of customers. Therefore, it is important to reduce time and cost at the step of manufacturing trial molds. In order to realize three dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, traditional machining process spends a lot of time in cutting product and the remained material causes trouble such as inconvenience for clean. In this work, a new machining process using the hot tool has been proposed to overcome those limitations. In the process, the hot tool moves the predetermined path and the heat of the tool decomposes the remained material. In order to set up the process, the hot tool to satisfy requirements is designed and the material thermal properties are obtained using the DSC and TGA machine. The relationships between process parameters and thermal radius of the tool are obtained through experiment.

• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1705-1723
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• 2008

Let n be a 2-step nilpotent Lie algebra which has an inner product <, > and has an orthogonal decomposition $n\;=z\;{\oplus}v$ for its center z and the orthogonal complement v of z. Then Each element z of z defines a skew symmetric linear map $J_z\;:\;v\;{\longrightarrow}\;v$ given by <$J_zx$, y> = for all x, $y\;{\in}\;v$. In this paper we characterize Jacobi fields and calculate all conjugate points of a simply connected 2-step nilpotent Lie group N with its Lie algebra n satisfying $J^2_z$ = A for all $z\;{\in}\;z$, where S is a positive definite symmetric operator on z and A is a negative definite symmetric operator on v.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.6
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• pp.295-300
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• 2010

Metathetic route for the $MWO_4$ (M=Zn, Co) particles is a simple method of synthesis and a viable alternative method in a short time. $MWO_4$ (M=Zn, Co) particles were synthesized using solid-state metathetic (SSM) method with microwave irradiation. The $MWO_4$ (M=Zn, Co) particles were formed completely at $600^{\circ}C$ for 3 h. The crystallization process, thermal decomposition and morphology of the $MWO_4$(M= Zn, Co) particles were evaluated. The characteristics of the SSM reaction and the formation of a high lattice energy by-product NaCl were discussed.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.132-140
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• 1997

This paper proposes systolic array architectures for compuataion of the 1-D and 2-D discrete wavelet transform (DWT). The proposed systolic array for compuataion of the 1-D DWT consists of L processing element (PE) arrays, where the PE array denotes the systolic array for computation of the one level DWT. The proposed PE array computes only the product terms that are required for further computation and the outputs of low and high frequency filters are computed in alternate clock cycles. Therefore, the proposed architecuter can compute the low and high frequency outputs using a single architecture. The proposed systolic array for computation of the 2-D DWT consists of two systolic array architectures for comutation of the 1-D DWT and memory unit. The required time and hardware cost of the proposed systolic arrays are comparable to those of the conventional architectures. However, the conventional architectures need extra processing units whereas the proposed architectures fo not. The proposed architectures can be applied to subband decomposition by simply changing the filter coefficients.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.497-501
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• 2009

When modal tests on the large structures and machinery are performed, it is in general difficult and inaccurate to use artificial excitation devices such as impact hammers, because of insufficient capacity of the device and different environmental conditions of the concerned structures. Therefore, the Operational Modal Analysis(OMA) technique, which is performed by measuring only vibration responses during the operation of the objective product, can be one alternative. In this paper, the way to identify natural frequencies, mode shapes and damping ratios of a ship by using the OMA during the sea trail is described.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.413-416
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• 2007

The adsorption and surface reactions of NO on a VO/V(110) surface have been investigated using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure, and temperature programmed desorption (TPD) technique. NO is molecularly adsorbed on VO/V(110) at 80 K. As the surface coverage of NO increases, the NO dimer is formed on the surface at 80 K. Both NO and (NO)2 are adsorbed on the surface with the N-O bond perpendicular to the surface. (NO)2 decomposes at ~100 K and the reaction product is desorbed as N2O. Decomposition of NO takes place when the surface temperature is higher than 273 K.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.707-711
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• 2019

The feasibility of waste concrete as a catalyst for the effective pyrolysis of polyethylene terephthalate (PET) was examined using thermogravimetric (TG) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) analyses. TG analysis results indicated that the maximum decomposition temperature of PET is not altered by the use of waste concrete, showing similar values (407 ℃ and 408 ℃ at 5 ℃/min). Meanwhile, the volatile product distribution data obtained from the Py-GC/MS analysis revealed that the use of waste concrete promoted the deoxygenation reaction via converting the oxygen containing products such as benzoic acids, benzoates, and terephthalates to valuable deoxygenated aromatic hydrocarbons including benzene, toluene, ethylbenzene, and styrene. This suggests that the waste concrete can be used as a potential catalyst for the production of valuable aromatic hydrocarbons from PET pyrolysis.

• Natural Product Sciences
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• v.4 no.2
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• pp.78-83
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• 1998

Chemical investigation on a sample of the needles of Himalayan Taxus baccata has resulted in the isolation of several taxoids including taxol (1) 10-deacetyl-baccatin III (2) and 2-deacetoxytaxinine J (3) along with different lignans (6 and 7) and simple phenolics (8, 9, 10, 11 and 12). The occurrence of 4-(4'-hydroxyphenyl)-butane-2-one and 4-(4'-hydroxyphenyl)-trans-but 3-ene-2-one (8) in Taxus species is reported for the first time. The $^{13}C-NMR$ spectral data of two rearranged taxiod constituents, brevifoliol (4) and 13-decinnamoyltaxchinin B (5) are presented. The acid-catalyzed decomposition of taxol has been discussed. The synthesis of other two constituents, rhododendrol (10) and hibalactone (7) has been described.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.69-70
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• 2003

최근 실내공기 질(IAQ : Indoor Air Quality)에 관한 인식이 높아지고 있으며 환경개선에 상응하는 기술 개발의 중요성이 크게 부각되고 있다. 실제 산업체에서는 여러 가스정화기술들이 오염물질제거에 이용되어 왔고, 그 한 분야인 N.T.P(Non-thermal plasma Process) 공정도 다양한 각도에서 연구가 수행되어 왔다. 그러나, 이 기술의 실용화를 위한 설계변수 개념의 연구는 부족한 실정으로, 이에 본 연구는N.T.P 공정에 의한 가스정화의 반 경험식 도출과 이를 이용한 성능 평가 고찰이 주목적이다. 또한, 반응기 통과 후 나오는 부산물을 동정하여, 차후 후단에 사용할 촉매를 결정 하고자 한다. (중략)