• Water for future
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• v.23 no.4
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• pp.487-497
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• 1990

The qualitative and quantitative prediction for the dispersion of thermal discharge from nuclear / fossil power plant, steel works etc. has significant roles for the cooling system. Design and environmental management. In this study, the several important physical properties for the behavior of a thermal discharge with strong turbulent and buoyant effects are described. The comparative evaluation between MIT and PDS models is carried out, which have the different model structures. In general, MIT and PDS models are commonly used to calculate the thermal discharge behavior with considering the ambient current and the angle of jet in an unstratified water body. The simulated results by these models have great discrepancies due to the different assumptions in modling.

• Particle and aerosol research
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• v.9 no.1
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• pp.23-29
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• 2013

Inertial impaction type mist eliminators are the most effective instruments to separate mist from the gas. In this work, the effect of the horizontal chevron type mist eliminators is characterized experimentally. Droplet size distribution and evaluation of removal efficiency of the chevron type mist eliminators at different gas flows were investigated using an aerosol particle size analyzer and a portable aerosol spectrometer, respectively. The experimental investigations showed that the mist removal efficiency in these instruments is dependent in the droplet size, and the pressure drop is nil.

• Korean Journal of Materials Research
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• v.18 no.3
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• pp.128-136
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• 2008

Evaluation of the solid surface properties by an analysis of the liquid penetration rate into powder beds is very important in applications of powder products. The penetration rate is related the surface property in powder beds. In order to analyze the surface property of powders, the contact angle values of several powders were obtained using the Washbun equation and the Wicking method. The surface free energy value ${\gamma}S$ was divided into a polar component ${\gamma}S^p$ and a dispersion component ${\gamma}S^d$. Inorganic powders such as calcite were used as test samples. The effects of the particle size and the type of experimental liquid on the penetration rate were measured. It was confirmed that the surface free energy of the grinding sample is smaller than that of the classification sample.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.3
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• pp.35-54
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• 2001

The Libraries are face to difficult of academic journal subscription for the increasing price of journal and the increasing number of journal. Bibliographic citation analysis is one of method of evaluating the use of a journal collection. This study is used bibliographic use and scatting of foreign academic journal in Library and Information Science found in doctorial dissertation of graduate students in Seoul city, for serve to complement another method of journal evaluation. Journal selection and cancellation may be done on the basis to dispersion of journal citation to usefulness of journal subscription in the library budget. But the library should not rely on one single evaluation technique, it should take advantage of combination technique.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.451-456
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• 2019

Our students are shocked by the results that there is an inverse proportion between academic achievement and life satisfaction. Recently, the Organization for Economic Cooperation and Development (OECD) published the PISA 2015 Student Well-Being Report. According to the report, Korean students' education is the highest among OECD countries, but their life satisfaction is the 47th ranked among the 48 OECD and non-OECD countries.[1] This is the cause of the unilateral education using collective achievement in evaluation methods. Therefore, I propose a personalized integrated model utilizing block chain technology. I suggest a personalized education and evaluation system model using selective education and personal approval rather than from teachers' unilateral education. This will no longer open the student's achievement grade system to the public. This change will be accomplished utilizing block chain technology. This technology is characterized by security, transparency and dispersion. The result of this work can be used to improve students' quality of living through a management system of personalized education and evaluation, based on the nature of education.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.179-187
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• 2010

For the user-centered interior space design, a designer needs to carefully focus on the details from which the user must keenly observe or concentrate on the space and how to deliberately check the image of the space. Following this view, for the user-centered interior space design this study analyzes the way which the space is represented from the perspective of the image assessment. The results obtained from this study are summarized as follows: First, this study analyzed the characteristic of space image change in the form of cross-comparison between one space and a rotated space. With analyzing of an eye fixation by showing the space, the space images of "concentration-dispersion" and "strengthening-weaken "have an important role in the analysis of the perception of space. it confirmed that the method of space perception was changed by rotated the space. Second, With changing quantities of image and extraction of deviation from adjective in survey, it quantitatively graps that respondents of feel in space perception by changing the space and "concentration" and 'dispersion" for process of space choice. The results of the research can provide important basis to judge the changing of space perception by visual perception. Third, through the analysis of image change rate and deviation rate, the characteristics of image change with space change can be analyzed. The results derived from the study provide the evidence to support the image change by space rotating.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.15-25
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• 2009

Donghae city is one of the most representative cement industrial city in Korea. The area is faced with the East Sea to the East and with high montane region of Tae-Back mountain range to the West. Many pollutant sources of air pollution are located near the coast, but the largest point sources of the region are located at the bottom of the mountain area in Donghae city. The local wind is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. This study was designed to evaluate enhancement of MM5 predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station, data only. The alternative meteorological fields predicted with and without FDDA were used to simulate spatial and temporal variations of NOx in combined with Atmospheric Dispersion Models (CALPUFF). For the modeling domain, the alternative meteorological fields with 1.1 km spatial resolution were interpolated to the CALMET with 0.5 km resolution. The vertical layers set to have 35 and 12 layers for MM5 and CALPUFF, respectively. MM5 with the FDDA did not resulted in significant improvement of meteorological field prediction in Donghae region, which is primarily because of complex geography and wind scheme. The result of CALPUFF, however, showed reduction of uncertainty errors by using the interpolation scheme of the actual measurement data.

• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.545-553
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• 2003

This paper is concerned with protecting piezoelectric transducers used in an ultrasonic flowmeter from the high temperature of hot fluid in a pipe by using a waveguide and with improving the propagation of ultrasonic longitudinal vibration in the waveguide. Waveguide material has been chosen for efficient insulation of heat transferred in the waveguide, and the minimum length of the waveguide for protecting piezoelectric transducer has been estimated. Forced response of the longitudinal vibration in a uniform circular rod has been obtained and the length of the waveguide has been selected for maximum amplitude. Longitudinal vibration response of a conically-tapered rod excited at a natural frequency has been obtained to confirm that wave motion is amplified as the cross-sectional size of the waveguide decreases along the axial direction. The fact that dispersion of a pulse wave in a waveguide is reduced as the cross-sectional radius is decreased has been examined theoretically and confirmed experimentally by using a single-rod waveguide. A bundle-type waveguide has proven to be a practical one through the evaluation of the wave propagation performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.657-664
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• 2013

By using shear mixing and ultrasonication, we fabricated specimens of well-dispersed multi-walled carbon nanotube composites. To confirm the proper dispersion of the filler, we used scanning electron microscopy images for quantitative evaluation and a tensile test for qualitative assessment. Furthermore, the coefficients of thermal expansion of several specimens having different filler contents were calculated from the measured thermal strains and temperatures of the specimens. Based on the microscopy images of the well-dispersed fillers and the small deviations in the measurements of the tensile strength and stiffness, we confirmed the proper dispersion of nanotubes in the epoxy. As the filler contents were increased, the values of tensile strength increased from 58.33 to 68.81 MPa, and those of stiffness increased from 2.93 to 3.27 GPa. At the same time, the coefficients of thermal expansion decreased. This implies better thermal stability of the specimen.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.299-310
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• 2003

In the evaluation of the subgrade stiffness structure by the SASW method, the calculation of the phase velocities is the important task controlling the reliability of the result. The interpretation of the phase spectrum should precede the phase-velocity calculation in the current practice of the SASW method. The difficulty involved in the interpretation prohibited the SASW method from being spread over to the industry. This study proposed a new method called the frequency-wave number technique, which is based on the frequency-wave number relationship of the surface wave in the multi-layered system. The frequency-wave number technique eliminates the expertise in the interpretation of the phase spectrum, automates the phase-velocity calculation and expedites the determination of the phase-velocity dispersion curve. To verify the validity of the proposed frequency-wave number method, the transfer function determined from the numerical simulation of the SASW measurements was used fir the calculation of the automatic calculation of the phase velocities and compared with the phase velocities by WinSASW employing the phase-unwrapping method. Also, the proposed method was applied to the real SASW measurements performed at$\bigcirc$$\bigcirc$area in GyeongGi-Do to see how the proposed method works with the real measurements.