• Journal of Powder Materials
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• v.9 no.5
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• pp.346-351
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• 2002

Pure and fine, two-component titanate powders (barium titanate, calcium titanate etc.) were synthesized by an ethylene glycol method. Titanium isopropoxide and other metal ionic salts were dissolved in liquid-type ethylene glycol without any precipitation. In non-aqueous system, the amount of ethylene glycol affected the solubility and homogeneity of metal cation sources in the solution. At the optimum amount of the polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. Most of the synthesized powders had sub-micron or nano-size primary particles after calcination and the agglomerated calcined powders were easily ground by ball milling process. All synthesized titanate powders had stable crystallization behavior at low temperature and high specific surface area after ball milling. The crystallization behavior and the microstructures of the calcined powders were affected on the ethylene glycol content.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.125-126
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• 2006

Data storage and data communication currently pose a major problems for all parties involved with power quality and power system monitoring. The Problem aries from the tremendous amount of data involved. There is a common desire in the power industry to find new techniques for high-accuracy data compression and data storage. This paper introduces a data compression technique that is very suitable for application to power quality waveforms. The proposed technique is applied in splitting the monitored signal into two components. Those are stationary and nonstationary components. Each component is compressed and encoded.

• Textile Coloration and Finishing
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• v.10 no.2
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• pp.18-28
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• 1998

in order to overcome disadvantage of the conventional two bath dyeing method of polyester/cotton blends, it had prompted significant effort to the development of the one bath dyeing method which can accomplish sayings in time, energy and water usage. Also, when dyeing polyester/cotton blends by the one bath dyeing method, the high salt concentrations needed for the reactive dye can cause particles of disperse dye, used for the polyester component, to aggregate. A supplementary problem that can occasionally be happened is the change of hue that occurs on dyed polyester in an alkaline dyebath. To improve dyeing property of polyester/cotton blends, cotton component was pretreated with epichlolohydrine-trimethylamine hydrochloride in aqueous solution of sodium hydroxide to produce a cationized cotton that can be dyed under neutral conditions with reactive dye in a non-electrolytic or il little electrolytic dyebath. The one bath dyeing method of polyester/cationized cotton blends with disperse dye/reactive dye mixture resulted in a satisfactory dyeing property and color yield in comparison with ordinary two bath dyeing method.

• Journal of The Korean Astronomical Society
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• v.43 no.6
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• pp.201-211
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• 2010

We present an analysis of the measurements of mid-eclipse times of V839 Oph, collected from literature sources. Our analysis indicates a period increase of $3.2{\times}10^{-7}$ day/yr. This period increase of V839 Oph can be interpreted in terms of mass transfer of rate $1.76{\times}10^{-7}M_{\odot}/yr$, from the less to the more massive component. The O - C diagram shows a damping sine wave covering two different complete cycles of 36.73 yr and 19.93 yr with amplitudes approximately equal to 0.0080 and 0.0043 day, respectively. The third cycle has to be expected to cover about 13.5 years with lower amplitude than those of the former two cycles. These unequal duration cycles show a non periodicity which may be explained as resulting from either the presence of a tertiary component to the system or cyclic magnetic activity variations due to star spots. For the later mechanism, the obtained characteristics are consistent when applying Applegate (1992) mechanism.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.811-819
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• 1999

A theoretical model to predict the effective thermal conductivity of sands Is developed by considering the participating heat transfer mechanisms and their relationship to the model geometry. Comparison between the calculations and the measurements indicates that the assumptions to introduce two model constants (${\phi}_{af}$ and ${\delta}$) for model development were justified. As a results, the model was proved to predict the effective thermal conductivities of 2- and 3-component systems of two silica sands saturated with fluids or bonded with liquid binders in a reasonable accuracy.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.29-34
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• 2021

Recently, many studies have considered the effect of atmospheric pressure loading (APL) on precise global navigation satellite system (GNSS) data processing. The APL deforms the Earth's crust. It can often exceed 10 mm in radial displacement. In this study, we analyze the APL effect on Multi-GNSS kinematic precise point positioning (PPP). In addition, observations received at two GNSS reference stations (DAEJ and SUWN) in South Korea were processed. The absolute position changes for the two stations were compared to before and after applying the APL effects from January 1 to February 29, 2020. The crust of South Korea was most affected by the APL in the up direction. With the APL model, the difference in daily position changes was mostly within 4 mm in the radial direction. On the other hand, the horizontal components (east-west and north-south) were relatively less affected than the radial component.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.511-517
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• 1993

Changes of the surface and interface tension with temperature for washing liquids and alkanes were measured by FACE surface tensiometer. Using the extended Fowkes' equation, the dispersion and polar force components of the surface tension were estimated. The results were as follows : 1. The surface tensions of washing liquids and alkanes decreased almost linearly with the increase of temperature. 2. The interface tensions of 0.25% DBS/alkane increased slowly with the increase of temperature. In the case of nonionic surfactant solutions, however, the interface tensions with alkanes varied with the number of hydrophilic ethylene oxide(EO) groups. 3. Of the surface tension of water at $20^{\circ}C$, the dispersion force component was 25.3 dyn/cm and the polar force component was 47.8 dyn/cm. As the temperature increased, both the polar and dispersion force components decreased in a similar fashion. 4. The dispersion force component of surface tension of 0.25% DBS solution was 30.0 dyn/cm, and the polar force component was 2.2 dyn/cm at $20^{\circ}C$. The two components decreased with the increase of temperature. 5. As the temperature increased, the dispersion force component of surface tension decreased and the polar force component increased significantly for 0.25% NPPG-7.5EO solution. In the case of 025% NPPG-10EO, both the dispersion and polar force components decreased slowly, but the polar force component is expected to increase from $60^{\circ}C$. However, the polar force component of surface tension decreased with the increase of temperature for 025% NPPG-15EO solution, and at the temperature higher than $60^{\circ}C$ the surface tension is expected to be composed of only dispersion force component.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.332-339
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• 2004

A technical analysis was conducted to predict the development trend for the highly efficient absorption type refrigeration system. The study was based on a submitted patent during January 1981 and December 2000 in Korea, Japan and America. The total number of extruded patents from the registered database was 24,822 and the filtering process makes the reduction of the data number to 3,510. Technical development of Japan for the absorption type refrigeration system is prominent compared to the other country due to approximately 75％ of the patents coming from Japan. When the patent is divided into two categories, the patent for component technology for the refrigeration system makes up 75％ and the refrigerating type technology 25％ of the patents. This shows technical development for the system component is advanced compared to the technology development for the system type. When the patents are classified by nationality of patent applicants, foreigners contribute up to 33％ of the patents in Korea. However, Japan's case shows the 99％ of the patents are invented by the Japanese. If the patents are classified to the International Patent Classification, most of the data for the absorption type refrigeration system belongs to IPC F25B.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.53-62
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• 1986

An Idea of Standard Rural Area(SRA), the rural areas which have higher ruralities of the rice cropping region and also higher urban characteristics, was conceptualized to develop the tentative basic indices necessary for rural settlement design in reclaimed land. The SRA's were determined by a technique of the principal component analysis with relevant data from 81 counties or cities located in the west side of Korea(Chon-Nam,Chon-Buk, Chung-Nam, Kyung-Ki Do).By the definition of the SRA, the principal component analysis is seperately carried out by two subworks, analyses of rurality and urban characteristics. From the analysis, rurality of the SRA is characterized by four components which appears to describe the scale of farm management, intensive farming, soundness of farming and farming basis on rice cropping, while urban characteristics of the SRA by three components to describe the accessibility, keeping ratio of infrastructures and level of medical services. Through grouping and synthesizing two characteristics of all counties by each component score, 24 counties were classified as urban-rural harmonized region which is the same result as that obtained from the extraction index being more than 50% of available area to total area except 1 county. Therefore, SRA is defined as the group of counties having more than 50% of available area to total area.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.6
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• pp.762-770
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• 2015

Fault tolerance is a crucial design for a mission-critical computer such as engagement control computer that has to maintain its operation for long mission time. In recent years, software fault-tolerant design is becoming important in terms of cost-effectiveness and high-efficiency. In this paper, we propose MPCMCC which is a model-based software component to implement fault tolerance in mission-critical computers. MPCMCC is a fault tolerance design that synchronizes shared data between two computers by using the one-way message-passing scheme which is easy to use and more stable than the shared memory scheme. In addition, MPCMCC can be easily reused for future work by employing the model based development methodology. We verified the functions of the software component and analyzed its performance in the simulation environment by using two mission-critical computers. The results show that MPCMCC is a suitable software component for fault tolerance in mission-critical computers.