• The Korean Journal of Rheology
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• v.3 no.1
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• pp.68-75
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• 1991

상업적으로 많이 이용되는 폴리에틸렌테레프탈레이트(PET)에 액정중합체(LCP)인 열방성 폴리에스터를 첨가하여 유변학적 특성을 조사하고 전단속도와 혼합비에 따른 LCP domain의 형태 변화를 고찰하였다. 모체고분자 내 구형과 타원형을 이루는 LCP domain들 은 신장력에 의해 피브릴 구조의 변형되고 이 피브릴은 흐름방향으로 배향되어 용융체에 윤 활제와 같은 역할을 함으로써 용융점도의 감소를 보이는데 특히 높은 전단속도 영역에서 LCP가 30wt%까지 첨가될수록 큰 폭으로 감소하였다. 주사식 현미경(SEM)의 관찰로부터 LCP domain의 피브릴구조를 확인할 수 있었고 또한 LCP domain의 형태 변화가 용융점도 가 감소에 직접 관계됨을 확인할 수 있었다.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.145-149
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• 2007

Electrochemical studies were performed for a single particle of nickel hydroxide for the cathode of Ni-MH batteries. A carbon fiber microelectrode was manipulated to make electrical contact with an alloy particle, and electrochemical experiments were performed. As a result of cyclic voltammetry, the oxidation/reduction and oxygen evolution reaction (OER) are clearly separated for a single particle. The total cathodic charge (Qred) is practically constant for the scan rate investigated, indicating that the whole particle has reacted. The total anodic charge(Qox) was larger than that of reduction reaction, and the magnitude of oxygen evolution taking place as a side reaction was enhanced at lower scan rates. As a result of galvanostatic charge and discharge measurement, the discharge capacity of single particle was found to be 250 mAh/g, value being very close to the theoretical capacity (289 mAh/g). The apparent proton diffusion coefficient(Dapp) using potential step method inside the nickel hydroxide was found to range within $3{\sim}4{\times}10^{-9}\;cm^2/s$.

• Journal of the Korean Vacuum Society
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• v.15 no.5
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• pp.512-517
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• 2006

A reliable linear translation system was constructed. The system has six piezo legs, attached to a main body, holding a hexagonal sapphire rod. The sapphire rod moves either forward or backward with the sequential motion of the piezo legs, driven by characteristic electric voltage waves. The translational system was tested in vertical direction. The speed of the sapphire rod was turned out to be constant during several mm travel. The slowest upward speed was measured to be ${\sim}1.7{\times}10^{-6}m/s$, yielding ${\sim}28.3nm/step$, while the slowest upward speed was ${\sim}3.7{\times}10^{-6}m/s$, with ${\sim}61.7nm/step$, due to gravitational force. The velocity increases linearly, as the amplitude of the voltage waves increases. The linear translation system will be used as a coarse approach part for a scanning tunneling microscope.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.84-88
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• 2006

The effects of tip voltage, deflection setpoint, and tip velocity on height of $SiO_2$ line drawn by local anodization on Si wafer using scanning probe microscope were investigated. No local anodization was detected at smaller than -3 V of tip voltage. The line height increased at rate of 0.47 nm/V when the tip voltage is stronger than -3 V at $1{\mu}m/s$ tip velocity. From deflection setpoint, mechanical force between tip and substrate could be calculated and the threshold farce was $12\sim18nN$. The height of anodized $SiO_2$ lines is independent of the magnitude of force above the threshold force. The line height decreased as increasing the tip velocity and limited to 0.7 nm at -5 V tip voltage.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.165-171
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• 2012

Here is implemented MATLAB program to analyze the characteristic curves of cyclic voltammetry which involves the multi-electron electrode reaction considered as key processes in electrochemical systems. For the electrochemical mass-transfer system, Fick's concentration equation subject to semi-infinite diffusion model for the boundary condition was discretized and solved by the explicit finite difference method. The resulting concentration values were converted into currents at each node by using Butler-Volmer equation. Based on the good agreement between the present numerical solution and the existing experimental results, effects of kinetic constants and CV scan rates on the reaction mechanism in multi-electron transfer processes were investigated effectively.

• Elastomers and Composites
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• v.39 no.4
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• pp.281-285
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• 2004

In this paper, the simple way to evaluate the value of the activation energy for the overall rate of free radical polymerization by using DSC thermograms was studied using free radical polymerization or butylacrylate as a model. Activation ehergies were determined at heating rates of 1, 2, 5, and $10^{\circ}C/min$ by applying the multiple scanning-rate methods of Kissinger, Osawa, and half-width methods as well as the single rate method of Barrett. The value of the overall activation energy measured was closely matched with the values calculated from individual data. This work also demonstrated that the use of the isoconversional method was a simple and effective way to estimate the activation energy for the overall free radical polymerization.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.535-541
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• 1997

The effect of concentration of each solution( HCI, $H_2SO_4$ and $HNO_3$), scan rate and polished surface condition on the corrosion of AISI 304 Stainless Steel were investigated, utilizing the Method ASTM G5 - 87. It can be concluded that: 1) For the same concentration(i.e. 1N) of each solution the corrosion rate is the highest in HCI and lowest in $HNO_3$. Also, the difference of values of $i_{cirt}$ generated for each solution is significant. 2) As the concentration of the solution $H_2SO_4$ is increased (O.5N, 1N, 2N) the values of $E_{cor}$ $i_{crit}$ and $i_{p}$ are increased. 3) In case of existence of SCN ion of O.OlN, the values of iCTIt and ip generated are approximately 100 times and 1.4 times higher respectively, than in the case of non - existence of $SCN^{-}$. However the existence of $SCN^{-}$ doesn't affect the value of $E_{cor}$ and $E_{p}$. 4) The values of $i_{crit}$ and $i_{p}$ are increased due to the increase of scan rate. But the values of $E_{cor}$ and $E_{p}$ do not depend on the scan rate. 5) The $i_{p}$ value depends greatly on oxygen in the solution, but the changes in values of $E_{cor}$ $i_{crit}$ and $E_{b}$ due to the oxygen are insignificant. 6) If a component is polished using #400, #600 and #800 wet polish paper, the effect of surface condition on variations of values of $i_{crit}$ and $i_{p}$ is slightly significant.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.11
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• pp.54-61
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• 2003

In this paper, an efficient non-scan design-for-testability (DFT) method for controller circuits is proposed. The proposed method always guarantees a short test pattern generation time and complete fault efficiency. It has a lower area overhead than full-scan and other non-scan DFT methods and enables to apply test patterns at-speed. The proposed method also shortens the test application time through a test pattern re-ordering procedure. The efficiency of the proposed method is demonstrated using well known MCNC'91 FSM benchmark circuits.

• Journal of fish pathology
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• v.5 no.2
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• pp.135-142
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• 1992

The absorption and excretion times of oxolinic acid(OX) used in farms as new aquatic antibiotics commonly were evaluated with determination of the effects of water temperature and feeding to parameters by using the bioassay technique. On the same time, antibacterial activity and the complex formation of oxolinic acid with serum proteins of two different fishes were compared to those oxytetracycline(OTC). With more than 10 times lower MIC values than those of OTC in the strains among 13 analyzed fish pathogens. OX did not show the decresed antibacterial activity by the binding of serum proteins in carp and tilapia. It implies more powerful potential of OX as aquatic medicine OTC. The serum concentration of OX after different administrations the oral, i.m., i.v and dipping methods were compared. The higher beginning concentration in serum and faster excretion times were obserbed in i.m. and dipping methods respectively. In the oral and i.m. administration, peak serum concentration after 24－48 hrs and slow excretion times demonstrated in both methods. These pharmacokinetic characteristics similar at $30^{\circ}C$ and $20^{\circ}C$ water temperature conditions, however, beginning serum concentration of OX in fish dipped in $50mg/\ell$ sol after starvation for 2 wks was appeared lower than those of fed fish. It suggests the importance of biological condition of the gill or skin for absorption of antibiotics after dipping administration.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.377-384
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• 2016

This is a study on the optimized dispensing of the auto dispenser used for the purpose of reducing the exposure dose and accurate radiation dose of radioisotope with regard to the PET/CT practitioners. The research method was to find the optimized dispensing method through evaluating the results according to the syringe type, dispensing rate, and vial pressure and through the application of corrected values. As a result of this study, 9.38 mCi has been dispensed on average in the case of 5 ml syringe, and the reproducibility close to 10 mCi was shown at the dispense of 9.55 mCi in the case of 3 ml syringe. In the evaluation according to the dispensing rate, the quantity of radioisotope close to 10 mCi was dispensed at the rate of 5 mm/min when the measurement was carried out by increasing the rate by 5 mm/min units in the order of 5, 10, 15 and 20 mm/min. In the evaluation result according to the vial pressure before/after the use of Needle filter, it was measured to be 9.53 mCi before use and 9.84 mCi after use confirming that the dispensing after using Needle filter showed the optimal value. In addition, in the evaluation of radioactivity before/after the application of corrected values according to the increase in dispense frequency, it was measured 9.53 mCi before correction and 10.07 mCi after correction confirming that the value with correction applied was closer to the quantitative value. Thus, a good optimized method was confirmed to use a 3 ml syringe with dispensing rate of 5 mm/min, to use a Needle filter at dispensing, and to set the corrected value of [$y=0.097{\times}x$] according to the dispensing frequency of equipment.