• International Journal of Ocean System Engineering
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• v.3 no.2
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• pp.90-94
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• 2013

This study represents the recent laboratory results from cathodic protection (CP) system with the use of sacrificial anodes at different environmental conditions (temperature of $10^{\circ}C$ and $40^{\circ}C$). Specimens were slab type with a dimension of $500mm{\times}50mm{\times}100mm$, and concrete cover thickness were 25mm. Zinc mesh and/or bulk type anodes were installed at the center of specimen to confirm the distance that CP system has influences on the specimen to distribute uniform CP current to rebar. Two different kinds of temperature condition were applied to verify the effect of temperature. Experiments were conducted for 60 days, and the distribution of potential and current that supplied from anode to rebar was measured. From the results, CP potential was varied with time, and temperature played an important role in CP potential variations. Current was also changed with time, and current distribution could be improved by installing additional bulk type anode.

• Journal of Surface Science and Engineering
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• v.12 no.1
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• pp.3-10
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• 1979

Many excellent Al-Zn-In anode have been developed up to the present. But for the purpose of the better performance of Al-Zn-In anodes in sea water the effect of calcium silicon addition on anodic polarization and current capacity of Al-Zn-In anodes was measured and analysed in sea water and artificial sea water. The results and conclusions obtained are summarized as follows. 1) Being compared with Al-Zn-In anodes, Al-Zn-In anodes containing 0.05% calcium silicon had superior characteristics in both anodic polarization and current capacity. 2) Corrosion patterns of the anodes containing calcium silicon were much more uniform than those of Al-Zn-In anodes. 3) In this experiment the most useful anode was Al-4% Zn-0.03% In-0.05% (Ca-Si). It had a capacity of 2.60Amp-hr of current/g and a voltage of 1.13(SCE reference) at anodic current density 1,000 4{\mu}A/cm^2$.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.2017-2022
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• 2008

Of the experiments to shorten NMR measuring time by sparse sampling, non-uniform sampling (NUS) is advantageous. NUS miminizes systematic errors which arise due to the lack of samplings by randomization. In this study, I report the real-time acquisition of 3D NMR data using NUS and maximum-entropy (MaxEnt) data processing. The real-time acquisition combined with NUS can reduce NMR measuring time much more. Compared with multidimensional decomposition (MDD) method, which was originally suggested by Jaravine and Orekhov (JACS 2006, 13421-13426), MaxEnt is faster at least several times and more suitable for the realtime acquisition. The designed sampling schedule of current study makes all the spectra during acquisition have the comparable resulting resolutions by MaxEnt. Therefore, one can judge the quality of spectra easily by examining the intensities of peaks. I report two cases of 3D experiments as examples with the simulated subdataset from experimental data. In both cases, the spectra having good qualitie for data analysis could be obtained only with 3% of original data. Its corresponding NMR measuring time was 8 minutes for 3D HNCO of ubiquitin.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.6
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• pp.837-855
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• 2019

The need of development of police officers' uniforms for the summer season has increased due to rises in temperature. This research developed a t-shirt typed of police officer's uniform for summer weather. We analyzed the design cases of national and international police officers' uniforms, similar types of uniforms, and t-shirts for summer weather. The satisfaction with current uniforms and preferences for these types of uniforms were surveyed with 1,062 police officers and public participants. Designs were developed and design opinions were surveyed with 1,011 public volunteers. A total of 584 police officers wore developed prototypes for two weeks, and surveys were conducted with 328 police officers to reflect the final design results. More than 80% of police officers have very satisfied or satisfied opinions of the developed designs. The study is expected to enhance police officers' satisfaction with the developed uniforms for summer weather.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.534-543
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• 2000

In this paper, when the current optical communication system is used for the DWDM. The FBG filter for the DWDN is able to reduce the interferences between the adjacent channels. In this paper, therefore, we find the relection spectrums for the three types of induced index changes, that is, uniform, Gaussian apodized, and raised-cosine apodized. From the obtained result in this paper, we can see that uniform FBG does not fit, and that the smaller the maximum induced index change $\sigma$ is and the larger the value of parameter C in the raised-cosine apodized FBG and G in the Gaussian apodized FBG are the fitter they are on the narrow filter for DWDM.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.364-370
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• 2013

In the current paper, we propose a new modeling algorithm to analyze the coupling between an incident electromagnetic field (EMF) and a twisted conducting line, which is a kind of non-uniform line. Typically, analysis of external field coupling to a uniform transmission line (TL) is implemented by the Baum-Liu-Tesche (BLT) equation so that the induced load responses can be obtained. However, it is difficult to apply this method to the analysis of a twisted conducting line. To overcome this limitation, we used a chain matrix composed of ABCD parameters. The proposed algorithm expands the dimension of the previous chain matrix to consider the EMF coupling effectiveness of each twisted pair, which is then applied to multi-conductor transmission line (MTL) theory. In addition, we included a comparative study that involves the results of each method applied in the conventional BLT equation and new proposed algorithm in the uniform two-wire TL case to verify the proposed method.

• Structural Engineering and Mechanics
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• v.39 no.1
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• pp.21-46
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• 2011

The natural frequencies of continuous systems depend on the governing partial differential equation and can be numerically estimated using the finite element method. The accuracy and convergence of the finite element method depends on the choice of basis functions. A basis function will generally perform better if it is closely linked to the problem physics. The stiffness matrix is the same for either static or dynamic loading, hence the basis function can be chosen such that it satisfies the static part of the governing differential equation. However, in the case of a rotating beam, an exact closed form solution for the static part of the governing differential equation is not known. In this paper, we try to find an approximate solution for the static part of the governing differential equation for an uniform rotating beam. The error resulting from the approximation is minimized to generate relations between the constants assumed in the solution. This new function is used as a basis function which gives rise to shape functions which depend on position of the element in the beam, material, geometric properties and rotational speed of the beam. The results of finite element analysis with the new basis functions are verified with published literature for uniform and tapered rotating beams under different boundary conditions. Numerical results clearly show the advantage of the current approach at high rotation speeds with a reduction of 10 to 33% in the degrees of freedom required for convergence of the first five modes to four decimal places for an uniform rotating cantilever beam.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.39-47
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• 2011

The motion of a conductive spherical particle under uniform electric field is investigated in order to find a suitable method for removing the conducting solid impurities contained in liquid plastic. When the positive dc voltage applied to the upper electrode, the vertical up-and-down motion of a charged particle by electrostatic force is observed by a charge-coupled device (CCD) camera or a high-speed video camera. The experimental data of the static threshold voltage by which the particle starts to move toward the counter electrode in air or silicone oil are in good agreement with theoretical value. When the applied voltage is larger than the static threshold voltage, the particle motion pattern in silicone oil consists of four stages: upward motion, stopping at the upper electrode, downward motion and stopping at the lower electrode. The stopping motion on the electrode is thought to be caused by the liquid flow accompanied by the particle motion. The particle charge calculated by integrating the pulse current, which is generated by the charge exchange between the electrode and the particle, is approximately 0.1~0.25 times of the theoretical value. This study is expected to help understand the electric properties of microparticles in oil circuit breaker (OCB) and oil transformer and improve their performance and longevity.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.818-822
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• 2003

We propose a software-reliability growth model incoporating the amount of uniform and Weibull testing efforts during the software testing phase in this paper. The time-dependent behavior of testing effort is described by uniform and Weibull curves. Assuming that the error detection rate to the amount of testing effort spent during the testing phase is proportional to the current error content, the model is formulated by a nonhomogeneous Poisson process. Using this model the method of data analysis for software reliability measurement is developed. The optimum release time is determined by considering how the initial reliability R(x|0) would be. The conditions are $R(x|0)>R_o$, $R_o>R(x|0)>R_o^d$ and $R(x|0)<R_o^d$ for uniform testing efforts. Ideal case is $R_o>R(x|0)>R_o^d$. Likewise, it is $R(x|0){\geq}R_o$, $R_o>R(x|0)>R_o^{\frac{1}{g}$ and $R(x\mid0)<R_o^{\frac{1}{g}}$ for Weibull testing efforts. Ideal case is $R_o>R(x|0)>R_o^{\frac{1}{g}}$.