• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.12-19
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• 2004

Using LSM (laser scanning method) , the radius of curvature due to thermal deformation in polyimide film coated on Si substrate is measured. Since the polyimide film shows viscoelastic behavior, i.e., the modulus and deformation of the film vary with time and temperature, we estimate the relaxation modulus and the residual stresses of the polyimide film by measuring the radius of curvature and subsequently by performing viscoelastic analysis. The residual stresses relax by an amount of 10％ at 100$^{\circ}C$ and 20% at 150$^{\circ}C$ for two hours.

• Journal of Korea Technology Innovation Society
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• v.7 no.2
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• pp.373-395
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• 2004

In year 2003, the Daedeok Science Town(DST) has celebrated its 30 years of anniversary and achievement in science and technology development. However, there is a criticism that DST has not played its expected role in Korea's National Innovation System. Recognizing this criticism, the development of DST was evaluated in the perspective of innovation cluster. The research shows that DST has been following the downstream path of evolution - from S＆T development to business development - and is in the early stage of R＆D-driven Innovation Cluster. Not only the development factors of DST innovation cluster were identified but the DST was compared with other internationally recognized innovation clusters. Finally, it is suggested that the business related functions should receive due attention in innovation cluster policy.

• Journal of Technology Innovation
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• v.14 no.3
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• pp.155-182
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• 2006

Science & Technology(S&T) personnel have been Playing a major role to develop our country since S&T is the most important factor in enhancing national competitiveness in the 21st century, As S&T activities are done by S&T personnel, it is essential to improve the welfare of S&T personnel in order to increase the performance of S&T activities. We should motivate them to pour their efforts and energy in S&T activities. However, the issue of S&T personnel's welfare has not been discussed sufficiently not only in academic research, but also in actual S&T policies. It has caused many social problems, for example, avoidance of S&T areas by young generation, low social recognition of S&T community, and so on. Under this background, this paper aims at investigating how to effectively improve S&T personnel's welfare. In this paper, we will suggest the 'Comprehensive Welfare Town for S&T personnel' as an effective instrument for improving of S&T personnel's welfare. In particular, we will discuss the detailed aspects of the comprehensive welfare town : objectives, strategies and budgets.

• Journal of the Korean Regional Science Association
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• v.39 no.4
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• pp.91-110
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• 2023

The purpose of this study is to explore urban issues that have arisen in the urban growth process of the 1st New Town for about 34 years since its construction through newspaper articles. For this purpose, newspaper articles related to the 1st New Town were collected using web crawling, and content analysis was conducted based on text mining. The main findings of the study are as follows. First, in the early stages of the construction of the 1st New Town, issues were diverse in the following six sectors: living service facilities, real estate, transportation, urban development and maintenance, safety, and housing supply, but gradually narrowed down to those of real estate and urban development and maintenance. Second, during the new town construction and urban stabilization stages, the network structure centered on 'Seoul' was maintained, which can be explained by the fact that the 1st New Town was geographically located on the outskirts of Seoul, and many articles compared the issues to Seoul. Third, the issue of urban aging appeared from the 10th year after construction, and the discussion on urban reorganization due to urban aging began in earnest from the 30th year after construction. The significance of the study is that it explored the urban issues that occurred throughout the urban growth process of the 1st New Town, and can be used as a basis for preparing a plan to reorganize the 1st New Town.

• Journal of Ginseng Research
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• v.10 no.2
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• pp.187-192
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• 1986

Activity of endogenous growth regulator in 4th year Panax ginseng root was investigated by second leaf sheath test of rice seedling and paper chromatogram of a acidic fraction of methanol extract before (March 28) and after (May 9) emergence of root bud, at the late season (Sept.4) and after leaf fall (November 11). GA$_3$ and ABA were used as reference. According to paper and high performance liquid chromatography of samples and authentic growth regulators the presence of insole acetic acid (IAA), gibberellic acid (GA$_3$) and abscisic acid (cis and trans ABA) was confirmed. These three regulators appeared to consist of major system though the existence of other regulators could not be ruled out. IAA activity seemed little changed through out the seasons. GA activity decreased in the later stages while ABA activity increased.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.18-18
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• 2002

Although it was suggested in 1962 that an efficient wavelength conversion could be achieved using ferroelectric crystals of periodic 180° domains, it was not until 1990's that quasi-phase-matching (QPM) became realized, as technology for periodic poling of LiNbO₃ crystals was readily available. Since ferroelectric domain inversion brings about change of the sign of second-order nonlinear susceptibility, periodically poled ferroelectric structures provide an ideal way of achieving QPM for second-harmonic generation and optical parametric oscillation. Periodically poled ferroelectric domains can also be utilized for optical devices, such as Brags electrooptic modulators. fabrication of stable periodic domain structures depends on a number of poling parameters of a ferroelectric crystal, such as coercive field, internal field and electrical conductivity. We present poling kinetics of KNbO₃ crystals, which involve domain nucleation and growth, backswitching, relaxation of internal field. Optimum poling conditions were established by designing a proper wave shape of external field. We demonstrate an efficient second-harmonic generation using QPM in a periodically poled KNbO₃ crystal.

• Bulletin of the Korean Chemical Society
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• v.15 no.1
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• pp.28-33
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• 1994

The laser-assisted chemical vapor deposition (LCVD) is described, by which the growth of single-phase GaN epitaxy is achieved at lower temperatures. Trimethylgallium (TMG) and ammonia are used as source gases to deposit the epitaxial films of GaN under the irradiation of ArF excimer laser (193 nm). The as-grown deposits are obtained on c-face sapphire surface near 700$^{\circ}$C, which is substantially reduced, relative to the temperatures in conventional thermolytic processes. To overcome the lattice mismatch between c-face sapphire and GaN ad-layer, aluminum nitride(AlN) is predeposited as buffer layer prior to the deposition of GaN. The gas phase interaction is monitored by means of quadrupole mass analyzer (QMA). The stoichiometric deposition is ascertained by X-ray photoelectron spectroscopy (XPS). The GaN deposits thus obtained are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and van der Pauw method.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.2
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• pp.44-50
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• 2008

This study presents test results of a mobile air-conditioning system using a potential alternative refrigerant, R152a. A series of performance tests have been carried out and cycle characteristics such as cooling capacity, energy efficiency ratio, suction and discharge pressures, and temperatures are presented, compared to those for the baseline R134a system. Tests were conducted with evaporation temperature of $5^{\circ}C$, condensation temperature of $45^{\circ}C$, subcooling temperature of $5^{\circ}C$, superheating temperature of $5^{\circ}C$, and compressor speed of 500-1500 rpm. The performance of R152a system with readjustment of an expansion valve showed better than those of R134a. The effect of oil on the pressure drop in the evaporator was also addressed.

• Journal of Conservation Science
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• v.25 no.1
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• pp.61-76
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• 2009

Gwangjueupseong (Gwangju Town Wall) has been found in the site of the Asian Culture Complex (former Provincial Government of Jeonnam) by archaeological field survey. The length of the remaining wall is 85.1m, and the Town Wall consists of ten kinds of rock type. The major rock types are dacite (41.1%) and andesite (35.7%). Dacite composes main rock blocks of the wall, and andesite is used to fill the cavity between main rock blocks. These rocks look very similar to basement rocks of the Mudeung Mountain on the basis of occurrence features, magnetic susceptibility, petrological, mineralogical and geochemical properties. Also, quarrying traces were found on the southwestern slope of the mountain along the Jeungsimsa Temple valley. Thus, it is probable that the rock materials of the Gwangju Town Wall were supplied from the Mudeung Mountain and that they were transported along the Gwangju river.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.3
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• pp.67-77
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• 2019

The purpose of this study is to introduce a town management system that utilizes private sectors and public space resources in urban management area. In this study, we are studying 7 town management districts in Japan which have been establishing diverse management systems that are propelled by the private sectors and private fund. We analyzed qualitative characteristics of 7 town management districts by surveying the operating status of organization, financial management and activities. Through the analysis, we clarified their characteristics that are related to establishing background. Also, we suggested conclusions of the study as follows: First of all, it is important to develop a town management method that takes into account the characteristics of the target district in order to overcome the limitation of applying uniform method and increase sustainability and efficiency of privately-led urban management. Second, marketing and promotion are critical strategies in town management since they are satisfying both private and public benefits. The high rate of reinvestment in marketing and promotions shows efforts to maintain the asset value of the private sector and continue to revitalize the city. Finally, in order to carry out urban management with private initiative, it is necessary to establish a working organization capable of realizing the operational direction of the steering committee to secure the executive power.