• Journal of Environmental Science International
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• v.10 no.5
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• pp.381-386
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• 2001

The characteristics of precipitation separation and solvent extraction separation of magnesium from the waste bittern were studied experimentally In the result of precipitation separation, the size of magnesium hydroxide precipitated was not affected on pH, but decreased with increasing the precipitation temperature. The purity of magnesium oxide precipitated was increased with pH beyond pH 11. From the solvent extraction separation, the equilibrium extraction ratio of magnesium was increased with pH and temperature of extraction phase, the concentration of stripping phase, and with decreasing pH of stripping phase. The extractant of Aliquat 336 and Acid 810 mixture was more effective than that of DCH18C6 and $D_2EHPA$ mixture in the extraction separation of magnesium.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.226-230
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• 2005

This paper describes the photocatalytic degradation properties by oxygen partial pressure for TiO$_2$ thin films fabricated by dc magnetron reactive sputtering. And the structural, chemical, optical and photocatalytic properties were investigated at various analysis system. When TiO$_2$ thin film was made at deposition time of 120 min and Ar:O$_2$ ratio of 60:40, the best properties were obtained. That results were as follows: thickness; 360∼370 nm, gram size; 40 nm, optical energy band gap; 3.4 eV and Benzene conversion in the photocatalytic degradation; 11 %.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.189-194
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• 2001

This paper presents a mew design of an inductive position sensing system with high sensitivity. The designed system consists of the driving coils, position-detecting coils, and closed loop formed magnetic blocks. To obtain high sensitivity we design a symmetric and closed loop type measuring system with small air-gaps. The elements that affect the system characteristics are turn ratio, excitation frequency, air-gap size, capacitance effect, and load resistance. By experimental investigation, the influences of these elements are examined and the system parameters are selected. The sensitivity of the newly designed system is greater than 2800mV/(V mm) and the linearity error is below${\pm}0.01%; in; the; range; of; {\pm}200{\mu}m$.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.227-227
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• 1999

Plasma display panel(PDP) is a leading technology for large-area flat panel displays. A current issue in operating the PDP cell is that the efficiency of the PDP cell is very low. To increase the efficiency of the PDP cell, the visible light needs to be maximized and the power consumption minimized. Since the excited xenons are related to the production of the visible light, it is important to optimize the cell geometry and the gas composition that produce the excited xenons more efficiently. A 2D-fluid code (FL2P) is developed and used to simulate the plasma dynamics and the radiation transport in the PDP cell. The cell is optimized with the code for various operating conditions and cell dimensions such as the voltage pulse, electrode length, electrode spacing, gap size, dielectric constant, gas mixture ratio, pressure, and pulse duration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.338-341
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• 2002

$(Ba_{1-x}Sr_{0.4}Ca_x)TiO_{3}$ (x=0.10, 0.15, 0.20) powders were prepared by the sol-gel method and BSCT thick films were fabricated by the screen-printing method. Their structural and dielectric properties were investigated with variation of composition ratio and $Al_{2}O_{3}$ doping contents. As results of the X-ray diffraction and microstructure analysis, the grain size of BSCT thick films was decreased with increasing $Al_{2}O_{3}$ amount. The thickness of BSCT thick films by 4-coating/drying is about $110{\sim}120{\mu}m$. The tunability increased with decreasing Ca content, and the BSCT(50/40/10) specimen doped with 1.0wt% $Al_{2}O_{3}$ showed the highest value of 12.94% at 5kV /cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.114-117
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• 2001

$(Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$(x=0.10, 0.15, 0.20) ceramics were fabricated by the mixed-oxide method and their structural and dielectric properties were investigated with variation of composition ratio and sintering temperature. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around $1020^{\circ}C$ due to the formation of the polycrystalline perovskite phase. BSCT(50/40/10) specimen sintered at $1500^{\circ}C$ showed the highest average grain size(18.25$[{\mu}m]$). Curie temperature and dielectric constant at room temperature decreased with increasing amount of Ca. BSCT(50/40/10) specimen sintered at $1450^{\circ}C$ showed a good dielectric constant, K, (=4324) and dielectric loss, $tan{\delta}$, (=0.972%) properties at 1[KHz].

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.213-220
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• 2003

By the localization of electro-chemical dissolution region, we succeeded in a few micrometer size hole drilling on stainless steel with the radial machining gap of about 1 ${\mu}{\textrm}{m}$. Tens of nanosecond duration voltage pulses were applied between WC micro-shaft and stainless steel in the 0.1 M $H_2SO_4$ solution. Pt balance electrode was used to drill the high aspect ratio micro-hole without generation of Cr oxide layer on the machined surface. The effects of applied voltage, pulse duration, and pulse period on localization distance were investigated according to machining time. We suggested the taper reduction technique especially brought up on blind-hole machining. High quality micro-holes with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and 12 ${\mu}m$ diameter with 100 ${\mu}m$ depth were drilled on 304 stainless steel foil. The various hole shapes were also produced including stepped holes and taper free holes.

• Journal of Veterinary Science
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• v.22 no.5
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• pp.60.1-60.9
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• 2021

Background: Echocardiography is a primary tool used by veterinarians to evaluate heart diseases. In recent years, various studies have targeted standard echocardiographic values for different breeds. Reference data are currently lacking in Maltese dogs and it is important to fill this gap as this breed is predisposed to myxomatous mitral valve disease, which is a volume overload disease. Objectives: To establish the normal echocardiographic parameters for Maltese dogs. Methods: In total, 23 healthy Maltese dogs were involved in this study. Blood pressure measurements, thoracic radiography, and complete transthoracic echocardiography were performed. The effects of body weight, age and sex were evaluated, and the correlations between weight and linear and volumetric dimensions were calculated by regression analysis. Results: The mean vertebral heart size was 9.1 ± 0.4. Aside from the ejection fraction, fractional shortening, and the left atrial to aorta root ratio, all the other echocardiographic parameters were significantly correlated with weight. Conclusion: This study describes normal echocardiographic parameters that may be useful in the echocardiographic evaluation of Maltese dogs.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.261-270
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• 2019

In order to protect secret digital documents against vulnerabilities while communicating, steganography algorithms are applied. It protects a digital file from unauthorized access by hiding the entire content. Pixel-value-difference being a method from spatial domain steganography utilizes the difference gap between neighbor pixels to fulfill the same. The proposed approach is a block-wise embedding process where blocks of variable size are chosen from the cover image, therefore, a stream of secret digital contents is hidden. Least significant bit (LSB) substitution method is applied as an adaptive mechanism and optimal pixel adjustment process (OPAP) is used to minimize the error rate. The proposed application succeeds to maintain good hiding capacity and better signal-to-noise ratio when compared against other existing methods. Any means of digital communication specially e-Governance applications could be highly benefited from this approach.

• Asia Pacific Journal of Corpus Research
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• v.4 no.2
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• pp.57-74
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• 2023

Having a firm grasp of technical terms is essential for learners of Japanese for Specific Purposes (JSP). This research aims to analyze Japanese nursing care vocabulary based on objective corpus-based frequency and subjectively rated word familiarity. For this purpose, we constructed a text corpus centered on the National Examination for Certified Care Workers to extract nursing care keywords. The Log-Likelihood Ratio (LLR) was used as the statistical criterion for keyword identification, giving a list of 300 keywords as target words for a further word recognition survey. The survey involved 115 participants of whom 51 were certified care workers (CW group) and 64 were individuals from the general public (GP group). These participants rated the familiarity of the target keywords through crowdsourcing. Given the limited sample size, Bayesian linear mixed models were utilized to determine word familiarity rates. Our study conducted a comparative analysis of word familiarity between the CW group and the GP group, revealing key terms that are crucial for professionals but potentially unfamiliar to the general public. By focusing on these terms, instructors can bridge the knowledge gap more efficiently.