• Journal of the Korean Society of Marine Environment & Safety
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• 제10권1호
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• pp.55-59
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• 2004

Temperature inversion off Wasaka Bay in the East Sea was studied using data measured on a CREAMS cruise in June of 1995 and 1996. Temperature inversion occurred mainly at the upper layer of the thermocline at a depth of no more than 20 m and around the thermal front between the TWC and the coastal waters of Japan. At some stations. temperature inversion had an influence un density inversion, while, in some other stations, high salinity water prevented density inversion.

• Journal of Environmental Science International
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• 제5권6호
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• pp.713-718
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• 1996

We identified two characteristic turbulent flow cases, weakening and strengthening, which appear at the downwind side. Observations were made two times, Dec. 2-3. 1995 and Feb. 13-14. 1996 at Pusan National University site located downwind side of Kumjeong mountain. Meteorological observation system, tethersonde, was adopted to present observation. In the case of the west wind which blows perpendicular to Sanghak mountain located westward from the site, the wind speed highly increased in exponential with height. Therefore, the low level wind speed was so weak just like Taylor(1988)'s review. While the wind speed was intensified at 200-400m layer when the northwest wind blows from the continental Siberian high. We suppose 기 is because of the strong vertical convergence of flow between the surface inversion layer and the upper one, and also the horizontal convergence along the saddle and valley between the two mountains, Kumjeong and Sanghak-because of Bernoulli's effect. The inversion layer existed at surface-l00m and 500-600m level and the strong wind existed at about 200-400m layer.

• Journal of the Korean earth science society
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• 제21권6호
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• pp.675-682
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• 2000

25 seismic shot gathers were obtained to study the two dimensional subsurface shear wave velocities in a landfilled area near the Keum river estuary. Borehole(BH#1 and BH#2) tests at two sites were made in the same area. Standard Penetration Tests were also performed at the same time. The 2-D shear wave velocity structure resulted from the inversion of the seismic data shows that the subsurface of the studied area consists of the upper 1${\sim}$3 meter thick layer(200 m/sec${\sim}$700 m/sec), the middle 5${\sim}$8 m thick low velocity layer(100 m/sec${\sim}$400 m/sec), and the lower layer of 1000m/sec or higher shear wave velocities. The thickness of the low velocity layer decreases from the BH #1 site to the BH #2 site. The depth to the basement also decreases toward the BH #2 site. The examination of the S wave velocity structure, the description of the geologic contents, and the Standard Penetration Test values indicate that the middle layer of low shear wave velocity may be related to the clay content of the layer. On the other hand, the Standard Penetration test values increase with depth, showing no significant relationship with the geologic contents of the subsurface. This study shows that the inversion of surface waves can be effective in the study of the shear wave velocity, especially in the area where low velocity layers can be found. The method of inversion of surface waves also can be used as a viable technique to overcome the limit of the seismic refraction method.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제25권8B호
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• pp.1469-1476
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• 2000

We have to consider the drain current as consisting of two components the vertical electric field and the longitudinal electric field because the drain current is almost totally due to the presence of drift in strong inversion of n-MOS FET. Especially the mobility of electrons in the inversion layer is smaller than the bulk mobility because the vertical electric field component that is generated by the effect of the gate voltage is perpendicular to the direction of normal current flow. By the multi-box segmentation technical method that are proposed in this paper we calculated the inversion layer depth and analyzed the vertical electric field component which has an large influence on mobility model.

• 한국해양학회지
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• 제27권4호
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• pp.259-267
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• 1992

A survey of CTD casting was taken in April 1991 in the eastern Yellow Sea. The vertical structure of water column consists of the upper mixed warm, the mid cold and the lower warm layers devised clearly by a seasonal thermocline and the temperature inversion. A strongest temperature inversion is found in the southern part of the survey area. Where the low-layer water is $3^{\circ}C$ higher than the mid-layer water. The area of the temperature inversion covers about $100{\;}km{\;}{\times}{\;}100{\;}km$ and it is observed 1.5 month later. The temperature and salinity of the low-layer water shows a core structure in vertical sections and the tongue-like distribution extending from the south to the north, implying that the warm and saline water found in the oceanic front south of the survey area in early spring is advocated to the north over 150 km underneath the Yellow Sea cold water.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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• pp.257-260
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• 2007

Two-dimensional (2D) interpretation of MT and AMT data observed in 2004 in Jeju Island is made using two inversion schemes developed by Uchida (1993) and Lee et al. (2002). These interpretations show that the subsurface of Jeju consists of roughly three layers. Reconstructed images along lines E and W reveal that the conductive layer beneath the topmost resistive layer of lava plateau can be a sediment layer. The geoelectrical structure along line E is more complex than that along line W, especially near Mt. Halla. The Uchida’s (1993) scheme gives reasonable images, but much more time-consuming than that of Lee et al. (2002).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.370-371
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• 2007

To investigate the ZnO thin films which are interested in the next generation of short wavelength LEDs and Lasers and UV photodetector with p-type inversion layer, the ZnO thin films were deposited by. RF sputtering system. Substrate temperature and work pressure is $100^{\circ}C$ and 15 mTorr, respectively, and the purity of ZnO target is 5N. The ZnO thin films were deposited at $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$. For sample deposited at $300^{\circ}C$, we observed full width at half maximum (FWHM) of 0.240 and good surface morphology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제19권2호
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• pp.119-125
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• 2019

Recently, it has become a social problem due to fine particles. There are more people wearing masks, weather alerts and disaster notices. Research and policy are actively underway. Meteorologically, the biggest damage caused by fine particles is the inversion layer phenomenon. In this study, we designed a system to warn fine Particles by analyzing inversion layer and wind direction. This weather information system proposes a system that can efficiently perform scalability and parallel processing by using OGC sensor web enablement system and NoSQL storage for sensor control and data exchange.

• Geophysics and Geophysical Exploration
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• 제10권4호
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• pp.314-321
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• 2007

Recently, multi-dimensional joint inversion of geophysical data based on fundamentally different physical properties is being actively studied. Joint inversion can provide a way to obtaining much more accurate image of the subsurface structure. Through the joint inversion, furthermore, it is possible to directly estimate non-geophysical material properties from geophysical measurements. In this study, we developed a new algorithm for jointly inverting dc resistivity and seismic traveltime data based on the multiple constraints: (1) structural similarity based on cross-gradient, (2) correlation between two different material properties, and (3) a priori information on the material property distribution. Through the numerical experiments of surface dc resistivity and seismic refraction surveys, the performance of the proposed algorithm was demonstrated and the effects of different regularizations were analyzed. In particular, we showed that the hidden layer problem in the seismic refraction method due to an inter-bedded low velocity layer can be solved by the joint inversion when appropriate constraints are applied.

• Journal of the Korean Geophysical Society
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• 제4권1호
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• pp.21-33
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• 2001

Simultaneous inversion of first-arrivals of local earthquakes recorded by the Korea Meteorological Administration(KMA) seismograph network from 1991 to 1998 is made to derive 1D crustal velocity structure of the Korean peninsula. Twenty-nine events with 178 observations are used in the inversion. Average crustal P-wave velocity turns out to be about 6.3 km/sec, and crustal thickness and upper mantle P-wave velocity are estimated as 33 km and 7.9 km/sec, respectively. Results of inversion indicate the possibility of the low velocity layer in the lower crust. Joint inversion is applied to estimate hypocenters, station delays, and velocities simultaneously. Relative station corrections for 11 stations range from zero to about 1.2 sec. Analysis of the synthetic data shows that estimates of hypocenter locations and station corrections as well as averaged crustal structure are reliable for the given data set..