• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1237-1243
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• 2013

This study has focused on the effect of ultrasonic vibration table in ELID grinding process of aluminum nitride ceramics. Aluminum nitride ceramics has superior physical and chemical properties and widely used in IC, LSI substrate, package and so on. To achieve the high effective machining of brittle and high strength ceramics as like aluminum nitride, machining method combined ELID grinding and ultrasonic vibration has been adopted in this study. From the experimental results, material removal rate, MRR has been increased maximum 36 percent and spindle resistance has been decreased in using ultrasonic table. Surface roughness of ground surface became a little worse in using ultrasonic table but was somewhat improved in feed direction.

• Geomechanics and Engineering
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• v.7 no.4
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• pp.355-374
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• 2014

An analytical solution of the fully coupled system of equations governing the plane strain deformation of a poroelastic medium with anisotropic permeability and compressible fluid and solid constituents is obtained. This solution is used to study the consolidation of a poroelastic clay layer with free permeable surface resting on a rough-rigid permeable or impermeable base. The stresses and the pore pressure are taken as the basic state variables. Displacements are obtained by integrating the coupled constitutive relations. The case of normal surface loading is discussed in detail. The solution is obtained in the Laplace-Fourier domain. Two integrations are required to obtain the solution in the space-time domain which are evaluated numerically for normal strip loading. Consolidation of the clay layer and diffusion of pore pressure is studied for both the bases. It is found that the time settlement is accelerated by the permeability of the base. Initially, the pore pressure is not affected by the permeability of the base, but has a significant effect, as we move towards the bottom of the layer. Also, anisotropy in permeability and compressibilities of constituents of the poroelastic medium have a significant effect on the consolidation of the clay layer.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.501-507
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• 2010

In this study, we evaluate the anti-microbiological activity of paraben in eye shadows that are composed of pigments and oil binders using various analytical methods and microbiological tests. Paraben does not show the microbiological activity properly when it was used with Nylon SP$^{(R)}$ 10, Talc RF SSA$^{(R)}$, OMC Talc AS$^{(R)}$ and $BaSO_4$. In the test of fungi, Nylon SP$^{(R)}$ 10 causes the decrease of microbiological activity regardless of the type of oil binders. The pigment of Mango violet also causes the decrease of microbiological activity when ester oil binder was used. Regardless of the type of oil binder, samples containing nylon SP 10, 0.15% of methyl paraben and 0.05% of propyl paraben had not been able to maintain microbiological activity only if the concentration of parabens were increased. Trace amounts of metal ions present in pigments reduced the activity of preservatives by inactivation of hydroxyl group of paraben. It is thought that swollen nylon SP 10 in ester oil increase the absorption or interaction of parabens and swollen nylon powder causes the inactivation of paraben.

• Toxicological Research
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• v.30 no.4
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• pp.311-316
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• 2014

For the detection of trace copper to be used in medical diagnosis, a sensitive handmade carbon nanotube paste electrode (PE) was developed using voltammetry. Analytical optimized conditions were found at 0.05 V anodic peak current. In the same conditions, various common electrodes were compared using stripping voltammetry, and the PE was found to be more sharply sensitive than other common electrodes. At optimum conditions, the working ranges of $3{\sim}19{\mu}gL^{-1}$ were obtained. The relative standard deviation of $70.0{\mu}gL^{-1}$ was determined to be 0.117% (n = 15), and the detection limit (S/N) was found to be $0.6{\mu}gL^{-1}$ ($9.4{\times}10^{-9}M$). The results were applied in detecting copper traces in the kidney and the brain cells of fish.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.11-16
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• 2012

In this paper, the authors formulate the sensitivity analysis algorithm for the natural frequency of a torsional shafting by expanding the transfer stiffness coefficient method. The basic concept of the present algorithm is based on the transfer of sensitivity stiffness coefficient, which is the derivative of stiffness coefficient with respect to design parameter, at every node from the first node to the last node in analytical model. The effectiveness of the present algorithm is confirmed by comparing the results of the sensitivity analysis and those of the reanalysis for the natural frequencies of a torsional shafting with a constant cross section. In numerical calculation, the design parameter is the diameter of the shaft element of the torsional shafting.

• Herbal Formula Science
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• v.20 no.2
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• pp.37-46
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• 2012

Objectives : Oyaksungi-san(Wuyaoshunqisan) has been used for treatment of stroke and rheumatoid arthritis in Korea. In this study, a simple and accurate high-performance liquid chromatography(HPLC) method was established for simultaneous determination of six main components, liquiritin, ferulic acid, naringin, hesperidin, neohesperidin, and glycyrrhizin in Oyaksungi-san, a traditional Korean herbal prescription. Methods : The analytical column for separation of six constituents was used a Gemini $C_{18}$ column maintained at $40^{\circ}C$. The mobile phase consisted of two solvent systems, 1.0% (v/v) acetic acid in $H_2O$ (A) and 1.0% (v/v) acetic acid in acetonitrile (B) by gradient flow. The flow rate was 1.0 mL/min and the detector was a photodiode array (PDA) set at 254 nm for glycyrrhizin, 280 nm for liquiritin, naringin, hesperidin, and neohesperidin, and 320 nm for ferulic acid. Results : Calibration curves were acquired with $r^2$ values ${\geq}0.9998$. The results of recovery test were 91.58%-105.90% with a relative standard deviations (RSDs, %) value less than 2.0%. The values of RSD for intra- and inter-day precision were 0.03%-1.72% and 0.03%-1.63%, respectively. The contents of the six compounds in Oyaksungi-san were 0.33-9.30 mg/g. Conclusions : The newly established HPLC method will be helpful to improve quality control of Oyaksungi-san.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.418-427
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• 2017

In Korea, interest in basic research is growing, in order to ensure the sustainable competitiveness of the main industries and to support world-class technology that can create high added value in the future. However, companies are known to encounter various problems when attempting to market products based on the results of basic research, which is known to be due to their lack of experience of commercialization and related activities. Therefore, in this study, we tried to analyze the effect of the technology commercialization activity stemming from basic science and technology research on the business performance. The technology commercialization activities are divided into experience of commercialization, complete charge department, and consulting on technology commercialization and we developed an analytical model that (distinguishes between?) the technology innovation activities and technology innovation capabilities and analyzed their impact on the business performance. As a result, the importance of technology commercialization activities was confirmed by the fact that it had a positive effect on the business performance, while the technological innovation activity was found to positively affect the management performance, demonstrating that it plays a strategic role in companies. Finally, it was found that the technology innovation capacity partially influences the management performance and that it is necessary to establish a strategic research and development infrastructure.

• Analytical Science and Technology
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• v.31 no.6
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• pp.240-246
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• 2018

The present study analyzed standard samples of three types of aluminum matrix certified reference materials (CRM) using GD-MS. Calibration curves were constructed for 13 elements (Mg, Si, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Sn, and Pb), with the slope representing the relative sensitivity factor (RSF). The x- and y-axes of the calibration curve represented ion beam ratio (IBR) and the authenticated value of the standard sample, respectively. In order to evaluate precision and linearity of the calibration curve, RSD and the coefficient of determination were calculated. Curve RSD for every element reflected high precision (within 10 %). For most elements, the coefficient of determination was ${\geq}0.99$, indicating excellent linearity. However, vanadium, nickel, and gallium curves exhibited relatively low linearity (0.90~0.95), likely due to their narrow concentration ranges. Standard RSF was calculated using the slope of the curve generated for three types of CRM. Despite vanadium, nickel, and gallium exhibiting low coefficients of determination, their standard RSF resembled that of the three types of CRM. Therefore, the RSF method may be used for element quantitation. Standard iron matrix samples were analyzed to verify the applicability of the aluminum matrix standard RSF, as well as to calculate the RSD-estimated error of the measured value relative to the actual standard value. Six elements (Al, Si, V, Cr, Mn, and Ni) exhibited an RSD of approximately 30 %, while the RSD of Cu was 77 %. In general, Cu isotopes are subject to interference: $^{63}Cu$ to $^{54}Fe^{2+}-^{36}Ar$ and $^{65}Cu$ to $^{56}Fe-Al^{3+}$ interference. Thus, the influence of these impurities may have contributed to the high RSD value observed for Cu. To reliably identify copper, the resolution should be set at ${\geq}8000$. However, high resolutions are inappropriate for analyzing trace elements, as it lowers ion permeability. In conclusion, quantitation of even relatively low amounts of six elements (Al, Si, V, Cr, Mn, and Ni) is possible using this method.

• Analytical Science and Technology
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• v.17 no.5
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• pp.393-400
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• 2004

Nitrosation of phenol (POH) was studied by adding hydrochloric acid and sodium nitrite to phenol solution with reaction temperature and time change. The optimum condition of nitrosation was found from the effects of hydrochloric acid and sodium nitrite concentration, reaction temperature, and reaction time changes on the production of nitrosophenol (POHNO). As a result, it was found that the optimum conditions were $5.0{\times}10^{-4}{\sim}2.0{\times}10^{-3}M$ range of $NO{_2}^-$ concentration, more than 0.10 M of HCl concentration, temperature of $80^{\circ}C$, and 3 hrs. of reaction time. In this condition, 10 U.S. E.P.A. classified priority environmental pollutant, phenols, were nitrosated. Nitrosated phenols were: POH, 2-Chlorophenol (2ClPOH), 2,4-diChlorophenol (2ClPOH), 2,4-dimethylphenol (24diMPOH), and 4-Chloro -3-methylphenol (4Cl3MPOH), and a small part of 2-nitrophenol (2NPOH). The ${\lambda}_{max}$ values of nitrosated phenols in acidic solution were around 300 nm, and those in basic solution were around 400 nm. Molar absorptivities (${\varepsilon}$) at the 400 nm of the nitrosated phenols in the basic solution were 1.5~2.0 times larger than those at 300 nm in acidic solution. It was also found by Capillary-HPLC chromatograms of the nitrosated phenol solutions that the production of the nitrosophenols were interfered by the excess concentration of nitrite (more than $3.0{\times}10^{-3}M$).

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.27-35
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• 2016

Purpose: Among RF pulses, a sinc pulse is typically used for slice selection due to its frequency-selective feature. When a sinc pulse is implemented in practice, it needs to be apodized to avoid truncation artifacts at the expense of broadening the transition region of the excited-band profile. Here a sinc pulse tailored by a new apodization function is proposed that produces a sharper transition region with well suppression of truncation artifacts in comparison with conventional tailored sinc pulses. A multiband pulse designed using this newly apodized sinc pulse is also suggested inheriting the better performance of the newly apodized sinc pulse. Materials and Methods: A new apodization function is introduced to taper a sinc pulse, playing a role to slightly shift the first zero-crossing of a tailored sinc pulse from the peak of the main lobe and thereby producing a narrower bandwidth as well as a sharper pass-band in the excitation profile. The newly apodized sinc pulse was also utilized to design a multiband pulse which inherits the performance of its constituent. Performances of the proposed sinc pulse and the multiband pulse generated with it were demonstrated by Bloch simulation and phantom imaging. Results: In both simulations and experiments, the newly apodized sinc pulse yielded a narrower bandwidth and a sharper transition of the pass-band profile with a desirable degree of side-lobe suppression than the commonly used Hanning-windowed sinc pulse. The multiband pulse designed using the newly apodized sinc pulse also showed the better performance in multi-slice excitation than the one designed with the Hanning-windowed sinc pulse. Conclusion: The new tailored sinc pulse proposed here provides a better performance in slice (or slab) selection than conventional tailored sinc pulses. Thanks to the availability of analytical expression, it can also be utilized for multiband pulse design with great flexibility and readiness in implementation, transferring its better performance.