• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.82-88
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• 2006

The objective of this paper is to get excitation forces of the engine. A powertrain geometry model is produced by CATIA and its FE model is made by MSC/Patran. A vibration mode analysis which makes us know the natural frequency and mode shape and a running mode analysis which measures the mode shape as a relative displacement about one reference point by measuring the acceleration of each bracket to take a place at the running vehicle are experimentally implemented. After getting a satisfied MAC value by doing a correlation about a measured mode analysis value and analyzed value through MSC/Nastran software, all components are assembled through MSC/ADAMS software which is a dynamic analysis tool. We can predict the vibration of brackets which is the last points to occur the force of the engine combustion by analyzing the combustion force produced by engine mechanism.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.257-262
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• 2010

The purpose of this study is to establish a basic culture system enabling in vitro culture of chicken blastodermal cells and to test the feasibility of retrovirus-mediated gene transfer to the cultured cells. The blastodermal cells were isolated from freshly laid eggs of stage X and cultured with or without STO feeder layer cells. Stem cell-like morphology was maintained after multiple passages and RT-PCR analysis proved expression of several stem cell specific genes. Immunocytochemical analysis using antibodies of anti-EMA-1 and anti-SSEA-1 also showed the feature of stem cells. Infection of the cultured blastodermal cells with LNCGW retrovirus vector resulted in successful transfer of foreign genes. The results of this study may be useful in establishing stem cell-mediated transgenic chicken production.

• Journal of Korean Neurosurgical Society
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• v.48 no.2
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• pp.173-176
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• 2010

In this report, we introduce an undetermined fibrous tumor with calcification occurring in the cerebellopontine angle (CPA). A 51-year-old woman was admitted with a short history of dizziness. Computed tomography and magnetic resonance images revealed a $2{\times}2{\times}2\;cm$ sized mass at the left CPA which was round and calcified. There was no dura or internal auditory canal involvement. At surgery, the tumor was located at the exit of 7th and 8th cranial nerve complex. It was very firm, bright yellow and well encapsulated. Histologic findings revealed that the tumor was predominantly composed of fibrous component, scant spindle cells and dystrophic calcification. Immunohistochemical staining demonstrated positive for vimentin and negative for epithelial membrane antigen (EMA), S-100 protein, CD34, factor XIIIa and smooth muscle actin. The diagnosis was not compatible with meningioma, schwannoma, metastatic brain tumors, and other fibrous tumors. Although the tumor was resected in total, long term follow-up monitoring is necessary due to the possibility of recurrence.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.47-53
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• 2004

Emulsion polymerization ws carried out using Alkyl methacrylate(RMA) like MMA, EMA, BMA and Styrene Monomer(SM) for core-shell latex preparation. It was synthesized at $80^{\circ}C$ in the presence of anionic surfactant SLS(Sodium Lauryl Sulfate). FT-IR and DSC analysis are used to confirm the synthesized core-shell emulsion latexes. Moreover DSC and TGA were used to investigate the thermal characterisitcs of them. The differences of the decomposition rate and the activation energy from TGA and DSC analysis are not so big. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene. For investigating combustion products, LC50 values were calculated by FED(Fractional Effective Dose)from the Pyrolyzer-Mass sepctrometer.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.83-94
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• 1996

EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of $100g/cm^2$ and 0.60 under $3kg/cm^2$, and water absorption ratio is $0.42{\sim}0.50$ and $1.0{\sim}1.02$ compressive strength ratio at mixed of water/PDCM-PED is 50 times.

• Journal of the Korean Applied Science and Technology
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• v.20 no.3
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• pp.221-229
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• 2003

A copolymer ${\sim}$550cps ; $M_n$, 2590${\sim}$2850 ; and conversion, 82${\sim}$89%, respectively. It was found from the plotting of $T_g$ versus viscosity and $T_g$ versus molecular weight that viscosity increased with $T_g$ while number averaged molecular weight decreased with increasing $T_g$.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.85-91
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• 2006

Acrylic resins (HSCs : EA/EMA/2-HEMA/CLA) which contain 80% solid content were synthesized by the copolymerization of monomers (ethyl acrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate) and functional monomer (caprolactone acrylate : CLA) which improves the crosslinking density and physical properties of films. The physical properties of the prepared acrylic resins (HSCs) containing CLA, are as follows: viscosity 1440$^{\sim}$2630 cps ; $M_n$ 1590$^{\sim}$1660 ; and conversions, 81$^{\sim}$86%, respectively. From the correlation of $T_g$ values, viscosities, and $M_n$ of the HSCs, it was found thst viscosity and $M_n$ increased with $T_g$ value.

• Journal of the Korean Applied Science and Technology
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• v.21 no.3
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• pp.197-203
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• 2004

Acrylic resins ($HSC_s$ : EA/EMA/2-HEMA/CLA) which contain 70% solid content were synthesized by the copolymerization of monomers (2-hydroxyethyl methacrylate, ethyl acrylate, and ethyl methacrylate) and functional monomer (caprolactone acrylate : CLA) which improves the crosslinking density and physical properties of films. The physical properties of the prepared acrylic resins (HSCs) containing CLA, are as follows : viscosity 245${\sim}$515 cps ; $M_n$ 2670${\sim}$2840 ; and conversions, 83${\sim}$91%, respectively. From the correlation of $T_g$ values, viscosities, and $M_n$ of the HSCs, it was found that viscosity and $M_n$ increased with $T_g$ value.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.341-344
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• 1999

본 논문에서는 DSP 기능을 내장한 32비트 RISC 마이크로프로세서를 위한 버스 제어기를 설계하였다. 연구의 초점은 버스 타이밍, 주소 멀티플렉싱, 리프레쉬, 버스 중재 등을 제어하는 버스제어기를 온칩화 하여 CPU로 하여금 외부 램과 추가적인 장치없이 직접 연결될 수 있도록 한 것이다. 버스 제어기가 관리하는 메모리의 종류는 SRAM, ROM, DRAM, EDO DRAM이며 고속 모드(Fast page mode, EDO page mode 및 RAS-down mode)기능을 지원하며 다양한 Wait를 넣을 수 있다. 주소 영역은 4가지(EMAO-EMA3)이며 내부적으로 7개 의 레지스터가 있고 이들을 이용하여 서로 연결된 세 개의 상태 머신으로 모든 램과의 타이밍을 제어함으로써 공유블록을 활용할 수 있었다. Verilog HDL의 기술하고 Synopsys로 합성한 후 타이밍 검증을 수행한 결과 최악조건에서 53.1㎒로 동작할 수 있었다. 그 후 0.6㎛ single poly triple metal process 공정으로 레이아웃 되었고 면적은 44㎜ × 1.21㎜ 이다.

• Journal of KSNVE
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• v.9 no.1
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• pp.163-173
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• 1999

Precise and reasonable modelling is necessary and indispensable to the analysis of dynamic characteristics of mechanical structures. Also. the effective prediction of the change of modal properties due to the variation of design parameters is required especially for the application of finite element method to the structural dynamics problems. To meet those necessity and requirement, three model updating algorithms are proposed for finite element methods. Those algorithms are based on sensitivity analysis of the modal data obtained from experimental modal analysis(EMA) and analytical modal analysis(AMA). The adapted sensitivity analysis methods of the algorithms are 1)eigensensitivity(EGNS) method. 2)frequency response function sensitivity(FRFS) method. 3)sensitivity based element-by-element method (SBEEM), Singular value decomposition(SVD) is used for performing eigenanalysis and parameter estimation in the updating process. Those algorithms are applied to finite element of a plate and the updating capability of each algorithm is compared in terms of accuracy. reliability and stability of the updating process. It is shown that the model updating method using frequency response function is superior to the other methods in view of various updating capabilities.