• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.155-159
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• 2003

Polycrystalline $Ti_{1-x}Co_xO_2$ thin films on $SiO_2$ (200 nm)/Si (100) substrates were prepared using liquid-delivery metalorganic chemical vapor deposition. Microstructures and ferromagnetic properties were investigated as a function of doped Co concentration. Ferromagnetic behaviors of polycrystalline films were observed at room temperature, and the magnetic and structural properties strongly depended on the Co distribution, which varied widely with doped Co concentration. The annealed $Ti_{1-x}Co_xO_2$ thin films with $x{\leq}0.05$ showed a homogeneous structure without any clusters, and pure ferromagnetic properties of thin films are only attributed to the $Ti_{1-x}Co_xO_2$ (TCO) phases. On the other hand, in case of thin films above x=0.05, Co clusters formed in a homogeneous $Ti_{1-x}Co_xO_2$ Phase, and the overall ferromagnetic (FM) properties depended on both $FM_{TCO}$ and $FM_{Co}$. Co clusters with about 10nm-150nm size decreased the value of Mr (the remanent magnetization) and increased the saturation magnetic field.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.5
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• pp.291-304
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• 2020

This paper examines the factors that drive temporal income diversification in rural areas of the Mekong River Delta in Vietnam, based on a framework that conceptualized diversification as a function of a household's capacity to diversify and incentives (both push and pull factors) to diversify. Drawing from five rounds of the Vietnam Living Standard Measurement Surveys covering a 13-year span (1993-2006), two panel datasets made from five cross-sectional samples are used for the analyses. The data are drawn from the Vietnam General Statistics Office. Both tobit model and Ordinary Least Squares model with random and fixed effects are applied. The main points emerging from the analysis is that income diversification is strongly influenced by household labor capacity. The relationship between household labor capacity and increasing insertion in non-farming wage activities is not driven by unobserved time-invariant factors such as household ability and motivation, but is instead driven by the higher labor capacity of households. In terms of the other household capacity variables, the effect of farm size is much larger in terms of retaining households in traditional occupations as compared to pushing them towards non-farm wage employment. Other variables such as household access to financial capital do not play an important role.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.399-403
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• 1998

Absorption coefficient per mass unit of particles, specific absorption coefficient, is one of main parameters in developing algorithms for ocean color remote sensing. Specific absorption coefficient of chlorophyll (a$^*_{ph}$) and suspended sediment (SS) were analyzed by "wet filter technique" and "Kishino method" for data sets observed in the Yellow and Mediterranean Seas. A new data-recovering method for the filter technique was also developed using spectrum slopes. This method recovered the baseline of spectrum that was often missed in the Kishino method. High a$^*_{ph}$($\lambda$) values in the oligotrophic Mediterranean Sea and low values in the Yellow Sea were observed, spanning over the range of 0.02 to 0.12 $m^2$/mg, at the chlorophyll maximum absorption wavelength 440nm. The empirical relationship between a$^*_{ph}$ and chlorophyll concentration was found to fit a power function, which was slightly different from that proposed by Bricaud et ai. (1995). Absorption specific coefficients for suspended sediment (a$^*_{SS}$) didn't show any relationship with concentrations of suspended sediment. However, the average value of a$^*_{SS}$ at 440nm was close to the specific absorption coefficient of soil (loess) measured by Ahn (1990). The more-pronounced variability of a$^*_{SS}$ than a$^*_{ph}$ perhaps can explain more wide range of size-distribution for SS, which were determined by their specific gravity and agitation of water mass in the sea surface.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.04a
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• pp.88-96
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• 1996

The characteristic analysis of fly ash generated from a fired power plant using bunker-C oil has been investigated. Ash size distribution by an optical microscopy with image processing technique, morphological shape by a scanning electron microscope(SEM) and microscope, chemical composition by the inductively coupled plasma emission spectrometry(ICP), and resistivity measurement as a function of temperature and moisture content by the resistivity meter are performed. A study of physical, chemical and electrical characteristics of bunker-C fly ash plays an important role of improving the performance of an electrostatic precipitator and protecting air pollution. The samples of bunker-C fly ash for analysis were collected from the electrostatic precipitator hopper of Ulsan Power Plant Unit 1 and Pusan Power Plant Unit 1. Mass median diameter(MMD) of bunker-C fly ash was measured 12.7${\mu}{\textrm}{m}$, while MMD of fly ash generated from the mixture of bunker-C oil(40%) and domestic anthracitic coal(60%) was 25.7${\mu}{\textrm}{m}$. The morphological structure of bunker-C fly ash consisted of fine particles of non-spherical shape. The primary chemical components of bunker-C fly ash were composed of SiO2(2.36%), Al2O3(4.91%), Fe2O3(14.33%) and C(11.84%). Resistivity of bunker-C fly ash was found to be increased with increasing temperature at the range of 100~15$0^{\circ}C$ and was measured 103~104 ohm-cm.

• Archives of design research
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• v.2 no.1
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• pp.117-130
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• 1989

Evaluation is to be seen a~ a central component of design activity. It is an attempt to ensure that the proposal which arises is accepted and that the resulting artefact itself suited to its purposes in practice. Recent surveys of Evaluation show that most methods require quantitative and explicit attributes. Always a significant part of the attributes of design proposals is qualitative. Therefore we need some study that convert qualitative attributes into quantitative scale values, because in many cases con\ulcornerclusions can be drawn about the order of the overall value of the design proposals. Following to Thurstone's psychological scaling methods, attributive values are assigned by ruting scale methods, met, hod of rank-order and method of paired comparisons. The problem of psycho\ulcornerlogical scaling is then to determine whether the stimuli can be ordered on a psychological continuum with respect to the degree of the attributes each possesses. The law of comparative judgement assumes that for a given stimulus there is associated a most frequently aroused or modal discriminal process on a psychological continuum. This paper is based upon the premise that the modal discriminul process will also be the same as the mean or median of the distribution.The objective of this paper is to argue for an acceptance of qualitative approaches to the evalua\ulcornertion of Design as a complement to the existing quantitative techniques. The scale values of 10 attri\ulcornerbutes \ulcorner(1) originality, (2) aesthetics, (3) satisfaction, (4) effeciency, (5) function, (6) size, (7) texture, (8) simplicity, (9) symbol, and (10) facility) in case of TV sets are obtained and their interactions are examined.

• KIEAE Journal
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• v.6 no.2
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• pp.51-57
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• 2006

With people's awareness of environment-friendly buildings recently increasing, there is a need to develop environment-friendly construction materials to reduce indoorair pollution levels. Thus, efforts to develop loess finishing materials that can replace the finishing materials currently being used (e.g., gypsum boards and chemical products) are underway. An analysis of the characteristics of domestic loess products,however, revealed that the cracks on loess products can be lessened and their strength can be improved by adding chemical ingredients to them. Thus, this research sought to use 100% natural materials and to develop loess finishing materials. In the experiments that were conducted in this study, appropriate mixture ratios of loess and sand/silica sand were found, and cracks and contraction ratio changes in samples were analyzed by differentiating the ratios of natural ingredients, such as lime, fine jute threads, gypsum, and jute cuttings. Loess'particle size distribution was found to have a high correlation with loess decoration, and it was discovered that the mixture of lime and fine chute threads could improve the contraction ratio. Through this study, which made use of natural ingredients, environment-friendly construction materials that can exercise the original function of loess were developed.

• Structural Engineering and Mechanics
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• v.38 no.5
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• pp.633-649
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• 2011

The paper presents a study aimed at understanding some characteristics of an interior explosion within a room with limited or no venting. The explosion may occur in ammunition storage or result from a terrorist action or from a warhead that had penetrated into this room. The study includes numerical simulations of the problem and analytical derivations. Different types of analysis (1-D, 2-D and 3-D analysis) were performed for a room with rigid walls and the results were analyzed. For the 3D problem the effect of the charge size and its location within the room was investigated and a new insight regarding the pressure distribution on the interior wall as function of these parameters has been gained. The numerical analyses were carried out using the Eulerian multi-material approach. Further, an approximate analytical formula to predict the residual internal pressure was developed. The formula is based on the conservation law of total energy and its implementation yields very good agreement with the results obtained numerically using the complete statement of the problem for a wide range of explosive weights and room sizes that is expressed through a non-dimensional parameter. This new formula is superior to existing literature recommendations and compares considerably better with the above numerical results.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.2
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• pp.122-129
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• 2003

This study was carried out in order to investigate the dextran formation and the internal structure of the chitosan-oligisaccharide(COS) Jeung-Pyun during the fermentation. To develop a functional Jeung-Pyun, COS was added to the rice at the level of 0, 2, 4, and 6% to the 2-hour-soaked rice. The pH, dextran and reducing sugar contents of COS batter, specific volume and the internal structure of COS were analyzed as a function of fermentation time. The specific volume of COS peaked at the 3 hour fermentation. The pH values of COS batters reduced with the fermentation time. The dextran content of the control batters peaked at the 7 hour fermentation. In contrast, the dextran contents of COS batters reduced up to 7th hour of fermentation, and then increased slowly until 20th hour of the fermentation process. From the air pore size and distribution of COS observed by SEM, the COS fermented fur 3 hour was judged as the best. It was concluded that COS prevented the fermation of dextran at the early stage of fermentation process.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.225-233
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• 2012

The research discusses interrelationship of structural and reliability importance measures which used in the probabilistic safety assessment. The most frequently used component importance measures, such as Birnbaum's Importance (BI), Risk Reduction (RR), Risk Reduction Worth (RRW), RA (Risk Achievement), Risk Achievement Worth (RAW), Fussel Vesely (FV) and Critically Importance (CI) can be derived from two structure importance measures that are developed based on the size and the number of Minimal Path Set (MPS) and Minimal Cut Set (MCS). In order to show an effectiveness of importance measures which is developed in this paper, the three representative functional structures, such as series-parallel, k out of n and bridge are used to compare with Birnbaum's Importance measure. In addition, the study presents the implementation examples of Total Productive Maintenance (TPM) metrics and alternating renewal process models with exponential distribution to calculate the availability and unavailability of component facility for improving system performances. System state structure functions in terms of component states can be converted into the system availability (unavailability) functions by substituting the component reliabilities (unavailabilities) for the component states. The applicable examples are presented in order to help the understanding of practitioners.

• Transactions on Electrical and Electronic Materials
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• v.17 no.4
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• pp.189-195
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• 2016

Micro Hotplate (MHP) is the key component in micro-sensors, particularly gas sensors. Indeed, in metal oxide gas sensors MOX, micro-heater is used as a hotplate in order to control the temperature of the sensing layer which should be in the requisite temperature range over the heater area, so as to detect the resistive changes as a function of varying concentration of different gases. Hence, their design is a very important aspect. In this paper, we have presented the design and simulation results of a meander micro heater based on three different materials - platinum, titanium and tungsten. The dielectric membrane size is 1.4 mm × 1.6 mm with a thickness of 1.4 μm. Above the membrane, a meander heating film was deposed with a thickness of 100 nm. In order to optimize the geometry, a comparative study by simulating two different heater thicknesses, then two inter track widths has also been presented. Power consumption and temperature distribution were determined in the micro heater´s structure over a supply voltage of 5, 6, and 7 V.