• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1160-1166
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• 2007

In this study, a new slab system that adjoint precast slabs are connected each other by viscoelastic material is proposed and numerical analysis is performed to evaluate the effect of the slab system on the vibration and noise control. Substructuring is introduced to develope the equation of motion of the slab system and the optimal properties of viscoelastic material are calculated. For the performance evaluation of the new slab system, the sound power and acceleration of the slab are compared with those of two way slab and the slab which the viscoelastic material is not connected. Numerical results show that the sound power of the new slab system can be reduced an amount of 6dB.

• Journal of the Korean Society of Visualization
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• v.5 no.1
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• pp.12-15
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• 2007

Macromolecule diffusion in cells and tissues is important for cell signaling, metabolism and locomotion. Biophysical methods, including non-invasive or minimally invasive in-vivo photobleaching techniques and single quantum-dot tracking, have been used to measure the rates of macromolecule diffusion in living cells and tissues, including central nervous system and tumors. Mathematical modeling and statistical analysis of experimental data revealed various modes of diffusion, which are strongly coupled with spatiotemporal changes in nanoscale structures and material properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.56-59
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• 2000

In this study, Ferroelectric $Pb(Zr_x,Ti_{1-x})O_3$(x=0.53) thin films were fabricated by the spin-coating on the Pt/Ti/$SiO_2$/Si substrate using the PZT metal alkoxide solutions with various excess Pb contents. Etching of PZT film was performed using planar inductively coupled Ar(20)$/Cl_2/BCl_3$ plasma. The etch rate of PZT film was 2450 ${\AA}/min$ at Ar(20)$/BCl_3$(80) gas mixing ratio and substrate temperature of $80^{\circ}C$. The leakage current densities of before etching and after etching PZT thin film were $6.25\times10^{-8}A/cm^2$, $8.74\times10^{-7}A/cm^2$ with electric field of 0.07MV/em, respectively.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.292-292
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• 1994

Catecholamines acting through ${\beta}$-adrenergic receptors regulate a wide range of metabolic activities in mammalian tissue. Of the various receptors coupled to adenylate cyclase, the ${\beta}$-adrenergic receptors are the most extensively characterized and have been purified from both nonmammal ian and mammal inn sources. However, most studies of the molecular properties of ${\beta}$-adrenergic receptors have been confined to peripheral tissues. Less progress has been achieved in characterizing the brain ${\beta}$-adrenergic receptor The goal of the present study was, therefore, to purify and characterize the neurotransmitter receptor proteins. To achieve this goal, the following stepwise experiments were performed. At first, the membrane-bound ${\beta}$-adrenergic receptors were. solubi1ized from brain tissue. Secondly, conditions for affinity chromatography were determined to purify the solubilized receptors effectively. Finally, the large-scale purification was performed and the characteristics of the purified ${\beta}$-adrenergic receptor were examined.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.1-8
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• 2014

Safety certification and inspection of dangerous machines and equipments used in industries are to save lives of workers and properties involved. Cause analysis of industrial accidents is essential to prove the effectiveness of such certification and inspection. This study focuses on suggesting systematic method for cause analysis of industrial accidents associated with dangerous machines and devices. Incorporating transition from the current user-oriented indirect regulations to more manufacturer and user balanced direct regulations, suggested method coupled with safety certification, safety inspection, safety management and safety education will guarantee more effective prevention of industrial accidents.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.11
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• pp.84-91
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• 2010

Heat treatment with carburized quenching process is widely used for automotive helical gear to improve its surface properties of hardness and strength. However, the gear can be deformed with the process over the allowable tolerance, which possibly makes noise, vibration and heat problems in operation. In this study, deformation of helical gear during heat treatment of carburized quenching was analyzed with a numerical method, incorporating coupled calculations of thermal conduction, carbon diffusion, phase transformation and thermal stresses. With the analysis, the effect of coolant temperature in quenching on the deformation was investigated. The result of the analysis revealed that the higher the coolant temperature became, the more change of helix angle and the more compressive stresses in the surface generated, because of delayed generation of martensite in the part.

• Journal of Photoscience
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• v.1 no.1
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• pp.15-23
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• 1994

The absorption and fluorescence spectral properties of piroxicam (PRX) in the hydrogenbonding solvents show the most sensitive dependence on the concentration ranging from 8 x 10$^{_5}$ to 2 x10$^{_5}$ M. These are attributed to both the solvent-mediated ground-state intermolecular proton transfer (GSIerPT) leading to formation of the ground state anion and the excited-state intmmolecular proton transfer (ESIraPT). The concentration dependences of the time-resolved emission kinetics at both room temperature and 77 K have also been investigated. It is shown that in the excited state, the ESIraPT of PRX is the dominant process to form a keto tautomer at the high concentration, whereas at the low concentration the excited-state conformational change of the anion is an additional process leading to formation of a zwitterion. The ESI~PT of PRX in the hydrogenbonding solvent is coupled with the ultrafast excited-state solvent reorganization.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.219-222
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• 1995

The objective of this study is to demonstrate the ability of a computer simulation of microstructural evolution in hot forging of C-Mn steels. The finite element method is applied to the prediction of the microstructural evolution, and it should be coupled with heat transfer analysis to consider the change of thermomechanical properties during the deformation. In this study, Yada's recrystallization model and rigid-thermoviscoplastic finite element method were employed in order to analyze microstructural evolution during hot forging process. To show the validity and effectveness of the proposed method, the experiment of hot compression process was accomplished and the results of experiment were compared with those of simulation. Consequently, this approach shows a good agreement with experimental results.

• Journal of the Korean Vacuum Society
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• v.3 no.2
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• pp.179-185
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• 1994

음극에 DLC 필름이 놓여져 있는 용량결합형의 RF 플라즈마 장치에서 Ar가스에 의한 방전에서 발생된 입자의 분포를 레이져 산란에 의하여 관측하였다. 발생된 입자들은 플라즈마와 sheath의 경계면 에서 높은 밀도의 구름을 이루었으며 시간에 따라 주기적인 분포의 변화가 반복되었다, 입자 구름의 발 생은 플라즈마 물성의 변화를 야기하였으며 그 결과로 심한 self-bias 전위의 감소현상이 관측되었다. 입자 구름분포의 시간에 따른 변화와 같은 주기의 self-bias 플라즈마전위의 진동현상이 가열된 fast-scanning langmuir 탐침에 의하여 관측되었다. 이결과는 입자 표면에로의 음전하 누적에 따른 전체 음전하의 이동도 감소에 의한 것으로 해석된다. 또한 방출 분광법에 의하여 입자오염상태의 Ar 플라즈 마와 정상상태의 Ar 플라즈마의 방출 선세기의 변화를 관측하였는데 입자구름 오염시의 2차전자 차폐 현상에 의해 높은 문턱 에너지를 가진 Ar II 선의 세기 감소현상이 나타났다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.510.1-510
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• 1986

Many enzymes require the participation of readily dissociable coenzymes as NAD for thir catalytic activities. The continuous utilization of the enzymes requires the retention and regeneration of the coenzymes. For this purpose, several kinds of macromolecular NAD derivatives have been prepared by covalently attaching NAD to watersoluble polymers. We have prepared poly (ethylene glycol)-bound NAD (PEG-NAD) by coupling N$\^$6/-(2-carboxyethyl)-NAD to one terminal of ${\gamma}$ $\omega$-diaminoly (ethylene glycol) (Mr 3000) with water-soluble carbodiimide. PED-NAD thus obtained has one NAD moiety located at a terminal of the linear, flexible and hydrophilic chain of poly (ethylene glycol). PED-NAD has good coenzyme activity for various dehydrogenases and is applicable in a continuous enzyme reactor. To use these macromolecular NAD derivatives in an enzyme reactor, it si necessary to understand the behavior of the system in which the reactions of dehydrogenases are coupled by the recycling of the NAD derivative. We investigated the kinetic properties of a continuous enzyme reactor containing lactate dehydrogenase, alcohol dehydrogenase and PEG-NAD. The steady-state behavior of the enzyme reactor is explained by a simple kinetic model.