• Atmosphere
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• v.27 no.1
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• pp.1-16
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• 2017

In this study, trends of upper jet stream characteristics (intensity, altitude, latitude, and longitude) over the Asia-North Pacific region during the recent 30 (1979~2008) years were analyzed by using four reanalysis datasets (CFSR, ERA-Int., JRA-55, MERRA). We defined the characteristics of upper jet stream as the averages of mass weighted wind speed, mass-flux weighted altitude, latitude and longitude between 400 and 100 hPa. Due to the vertical averaging of jet stream characteristics, our results reveal a weaker spatial variabilities and trends than previous studies. In general, the four reanalysis datasets show similar jet stream properties (intensity, altitude, latitude and longitude) although the magnitude and trends are slightly different among the reanalysis datasets. The altitude of MERRA is slightly higher than that of others for all seasons. The domain averaged intensity shows a weakening trend except for winter and the altitude of jet stream shows an increasing trend for all seasons. Also, the meridional trend of jet core shows a poleward trend for all seasons but it shows a contrasting trend, poleward trend in the continental area but equatorward trend in the Western Pacific region during summer. The zonal trend of jet core is very weak but a relatively strong westward trend in jet core except for spring and winter. The trends of jet stream characteristics found in this study are thermodynamically consistent with the global warming trends observed in the Asia-Pacific region.

• 전기의세계
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• v.29 no.2
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• pp.111-117
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• 1980

Contacts formed by vacuum evaporation of As-Te-Si-Ge chalcogenide glass onto Al metal (99.9999%) are studied by measuring paralle capacitance C(V), Cp(w), resistance R(V), Rp(w), and I-V characteristics. The fact that contact metal alloying produced high-resistance region is confirmed from the measurements of parallel capacitance and resistance. From the I-V characteristics in the pre-switcing region, it is found that electronic conduction and sitching occurs in the vicinity of metal-amorphous semiconductor interface. From the experimental obsevations, it is concuded that the current flow in the thin film is space-charge limited current (SCLC) due to the tunneling of electrons through the energy barriers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.980-986
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• 2009

In a triple-layered structure of ITO/N,N'-diph enyl-N,N'bis(3-methylphenyl)-1,1' - biphenyl-4,4'-diamine(TPD)/tris(8-hydroxyquinoline)aluminum($Alq_3$)/(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP)/Al device, we have studied the electrical and optical characteristics of organic light-emitting diodes(OLEDs) depending on the deposition condition of BCP layer. Several different sizes of holes on boat and several different deposition rates were employed in evaporating the organic materials. And then, electrical properties of the organic light-emitting diodes were measured and the performance of the devices was analyzed. It was found that the hole-size of crucible boat and the evaporation rate affect on the surface roughness of BCP layer as well as the performance of the device. When the hole-size of crucible boat and the deposition rate of BCP are 1.2 mm and $1.0\;{\AA}/s$, respectively, average surface roughness of BCP layer is lower and the efficiency of the device is higher than the ones made with other conditions. From the analysis of current density-luminance-voltage characteristics of a triple layered device, we divided the conductive mechanism by four region according to applied voltage. So we have obtained a coefficient of ${\beta}_{ST}$ in schottky region is $3.85{\times}10^{-24}$, a coefficient of ${\beta}_{PF}$ in Poole-Frenkel region is $7.35{\times}10^{-24}$, and a potential barrier of ${\phi}_{FN}$ in Fower-Nordheim region is 0.39 eV.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.123-129
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• 1996

LDD structure is widely accepted in fabricating short channel MOSFETs due to reduced short channel effect originated form lower drain edge electric field. However, modeling of the LDD device is troublesome because the analysis methods of LDD region known are either too complicated or inaccurate. To solve the problem, this paper presents a nonlinear resistance model for the LDD region based on teh fact that the electron mobility changes with positive gate bias because accumulation layer of electrons is formed at the surface of the LDD region. To prove the usefulness of the model, single source/drain and LDD nMOSFETs were fabricated with 0.35$\mu$m CMOS technolgoy. For the fabricated devices we have measured I$_{ds}$-V$_{gs}$ characteristics and compare them to the modeling resutls. First of all, we calculated channel and LDD region mobility from I$_{ds}$-V$_{gs}$ characteristics of 1050$\AA$ sidewall, 5$\mu$m channel length LDD NMOSFET. Then we MOSFET and found good agreement with experiments. Next, we use calculated channel and LDD region mobility to model I$_{ds}$-V$_{gs}$ characteristics of LDD mMOSFET with 1400 and 1750$\AA$ sidewall and 5$\mu$m channel length and obtained good agreement with experiment. The single source/drain device characteristic modeling results indicates that the cahnnel mobility obtained form our model in LDD device is accurate. In the meantime, we found that the LDD region mobility is governed by phonon and surface roughness scattering from electric field dependence of the mobility. The proposed model is useful in device and circuit simulation because it can model LDD device successfully even though it is mathematically simple.

• Journal of the Korean Geographical Society
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• v.43 no.3
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• pp.432-447
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• 2008

This study is to examine and analyze the the connection types between location knowledge and understanding the characteristics of world regions which 8th grade students are recognizing. In the analysis of the relation between the location knowledge and region understanding(clothing, food, housing and living style and so on), I analyzed the relation types between location knowledge and region living figures. Absolutely understanding the region needed the efact location knowledge on the world map, the knowledge of the longitude and latitude, symbolic area and the higher ranking region and the information about natural surroundings in which I grasp the region living figures. In addition, it needed the knowledge of locational attributes for the connection formation between region location knowledge on maps and understanding the region. The relative location knowledge related to the other regions and those natural surroundings and the linkage of those region locational attributes are needed in order that the location knowledge on a map could be connected to the knowledge about the actual region living figures. So I call it 'the structured location knowledge'. In order to form the structured location knowledge, the location knowledge of region on a map have to be connected to the multiple knowledge about absolute and relative locations with the knowledge of diverse location attributes. Therefore, it would be necessary that the location teaming for getting the characteristics of region have to be systematically accomplished departments of location-climate$^{\circ}{\mathbb{S}}$geographical features-region living figures.

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.77-90
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• 1999

This paper aims to understand the changing characteristics of the Kumi region as a locality in Korea through the regional geography of the world-system approach. To illustrate the changing regional characteristics, we analyzed the economic characteristics or position of the Kumi region within the world-economy and its spatial structure with three divisions of Korean capitalist periods: the Japanese colonial period ($1910{\sim}1945$), the social chaos period ($1945{\sim}1960$), and the economic development period ($1960{\sim}$present). In the Japanese colonial and social chaos periods, as Korean society was incorporated into the peripheral zone within the world-System (world-economy), Kumi also was made into a peripheral agricultural area. As a result, the Kumi region shaped the rural spatial structure without an urban center or regional dominant center. In the development period, influenced by the manufacturing-centered economic policy which boosted Korea as a semi-periphery within world-economy, Kumi also was developed into an industrial region(or semi-periphery) with the establishment of the Kumi electronic and textile industrial complex. This industrialization transformed the rural spatial structure of Kumi into a core (urban center)-periphery (rural area) structure. As we identified above, the regional geography of the world-system approach turned out to be a useful methodology to study a locality or internal region. Therefore we should make efforts to study such regions through the regional geography of the world-system approach.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.3
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• pp.83-90
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• 1999

This study was carried out to investigate the characteristics of trihalomethane (THM) formation from chlorination of groundwater in the northeastern area of Cheju Island. Effects of total organic carbon (TOC) and bromide in groundwater on the THM formation were studied. Samples were taken from two regions withe altitude. The concentrations of TOC and bromide in groundwater were higher at the regions of lower altitude, especially at the altitude below 50m. Generally the THM formation in GA region containing a high TOC was higher than that in GB region containing a relatively high bromide. At the altitude below 100m, the formation of total and brominated THM was highest at GB region. The most part of THM formation was brominated THM at GB region. The formation ratio of chloroform and brominated THM was similar to the others. Among the brominated THM, dibromochloromethane and bromoform in GB region were containing high bromide. Bromodichloromethane and dibromochloromethane in GA region were containing low bromide. At the altitude above 200m, chloroform was formed mainly. Comparing the ratio of brominated THM of total THM in Cheju Island with that in other areas, Seoul and Pusan, it can be konwn that the former showing 51.3% was much higher than the latter showing 6.7% and 28.8%, respectively.

• SUVANNABHUMI
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• v.8 no.1
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• pp.121-146
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• 2016

Defining key characteristics of Southeast Asia requires historical interpretation. Southeast Asia is a diverse and complicated region, but some of modern history's "grand narratives" serve to unify its historical experience. At a minimum, the modern history of the region involves decisive encounters with universal religions, the rise of Western colonialism, the experience of world wars, decolonization, and the end of the "cycle of violence". The ability of the region's peoples to adapt to these many challenges and successfully build new nations is a defining feature of Southeast Asia's place in the global stage. This paper will begin with a question: is it possible to develop a hermeneutic of "expedience" as a way to interpret the region's history? That is, rather than regard the region from a purely Western, nationalist, "internalist" point of view, it would be useful to identify a new series of interpretative contexts from which to begin scholarly analysis. In order to contextualize this discussion, the paper will draw upon the writings of figures who explored the region before knowledge about it was shaped by purely colonist or nationalist enterprises. To this end, particular attention will be devoted to exploring some of John Furnivall's ways of conceptualizing Southeast Asia. Investigating Furnivall, a critic of colonialism, will be done in relation to his historical situation. Because Furnivall's ideas have played a pivotal role in the interpretation of Southeast Asia, the paper will highlight the intellectual history of the region in order to ascertain the value of these concepts for subsequent historical interpretation. Ultimately, the task of interpreting the region's history requires a framework which will move beyond the essentializing orientalist categories produced by colonial scholarship and the reactionary nation-building narratives which followed. Instead, by beginning with a mode of historical interpretation that focuses on the many realities of expedience which have been necessary for the region's peoples, it may be possible to write a history which highlights the extraordinarily adaptive quality of Southeast Asia's populations, cultures, and nations. To tell this story, which would at once highlight key characteristics of the region while showing how they developed through historical encounters, would go a long way to capturing Southeast Asia's contribution's to global development.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.154-160
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• 2004

The purpose of this study was to evaluate airborne concentrations and characteristics of TSP, IPM, TPM and RPM in Seoul subway stations. Sampling was performed at 14 stations from April 11 to 29, 2002. Size-selective dust concentrations and metal concentrations were measured by gravimetric method and ICP-AES, respectively. The geometric mean of TSP, IPM, TPM and RPM concentrations in Seoul subway stations were 176$\mu\textrm{g}$/㎥, 348$\mu\textrm{g}$/㎥, 158$\mu\textrm{g}$/㎥ and 104$\mu\textrm{g}$/㎥, respectively. Dust concentrations in pathway were the highest and those in lobby were the lowest. The size distribution of dusts was significantly different by location of collection. When the deposition rate into pulmonary gas exchange region was estimated by size distribution, the deposition rate of dust collected from platform was higher than those of dust collected from lobby and pathway. The lower the basement levels were, the higher the deposition rates of dusts into tracheobronchial region and gas exchange region were. Copper and iron concentrations measured in platform higher were than those in other areas.