• Title/Summary/Keyword: central northern area

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Current Structure and Variability in Gwangyang Bay in Spring 2006 (2006년 봄철 광양만 해류의 구조와 변동)

  • Lee, Jae-Chul;Kim, Jeong-Chang
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.3
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    • pp.219-224
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    • 2007
  • Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

A Study on the Cooling Degree Days and the Number of Cooling Days in Korea (우리나라의 냉방도일과 냉방일수에 관한 연구)

  • Seol, Dong-Il;Min, Byeong-Eon
    • Journal of the Korean Institute of Navigation
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    • v.15 no.4
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    • pp.41-58
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    • 1991
  • The cooling degree days and the number of cooling days are used as important research materials not only in the field of design for building and cooling facilities but also in the government's establishment of energy policy. The purposes of this dissertation are to clarify the distribution of the cooling degree days and the number of cooling days by using the daily mean air temperature of 95 weather stations in Korea, and to show the distribution charts of the same cooling degree days and the same number of cooling days in order to help the practical uses of the materials. In cases of the base temperatures $24^{circ}C$, $25^{circ}C$, $26^{circ}C$, and $27^{circ}C$, the cooling degree days and the number of cooling days are shown in Table 5. The distribution charts of the same cooling degree days and the same number of cooling days are shown in Fig. 6 to Fig. 8 and Fig.9 to Fig. 11 respectively. As a result of this dissertation, Jeju Island and southern inland regions(especially Jeonju, Daegu, Gwangju) have a larger value than central regions and northern regions because of the influences of the terrain effect, and western coast regions have usually a larger value than eastern coast regions at the same latitude. The largest value appears in August of the year and the second in July, and the smallest in September. And southern inland area surrounded by Imshil, Goechang, and Boeun has a much smaller value than the other areas of its vicinity.

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An Ecological Study on the Vegetation of Dumi Island (두미도 식물상에 관한 생태학적 연구)

  • Lee, Il Koo;Kyu ha Park
    • Journal of environmental and Sanitary engineering
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    • v.5 no.1
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    • pp.34-45
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    • 1990
  • The purpose of this reserch is to investigate the flora of Dumi Island. This island locates at $128^{\circ}$ 13' E. longitude and $34^{\circ}$ 41' N. latitude. As a result of our investigation, the distribution of plants on Dumi Island could be summarized as follows. The vascular plants through this investigation were 66 families, 121 genera, 127 species, 16 varieties, 2 forma, and 145 kinds. From 1945 to 1960, most Pinus densiflora and Quercus mongolica were cut and sent as fuel to the cities of Masan, Chungmu and Samchunpo. After these deforestation years, there was a change of policy in the area and then wood was substituted by coal blacks as fuel and along with this occurs reforestation. Because of the reforestation by the present administration and natural means of suctrees, Castamopsis cuspidata var. thunbergii, Camellia japonica and Machilus japonica; they were found to exist near Sheonangdang in the northern region at Hakli and at Kuchun in the south. In the central part of the island at Mt. Chunhwang there are slopes of 20-30 degrees which are cultivated by the islanders this mountain which can be cultivated and 65% or 830 islanders are farming this land. Although this 125.4 hectors is not a large portion, this mountain with its variety of growth at different elevations, seems to be very fertile causing thick growth at any level.

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Sedimentary Environments in the Hwangdo Tidal Flat, Cheonsu Bay (천수만 황도 갯벌의 퇴적환경)

  • Woo, Han Jun;Choi, Jae Ung;Ryu, Joo-Hyung;Choi, Song-Hwa;Kim, Seong-Ryul
    • Journal of Wetlands Research
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    • v.7 no.2
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    • pp.53-67
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    • 2005
  • Cheonsu bay, which is typically a semi-closed type, is characterized by various environments such as channels, sand bars, small islands and tidal flats. The construction of Seosan A and B sea dikes from 1983 to 1985 might continuously change sedimentary environments in the northern part of the bay. In order to investigate sedimentary environment, surface and core sediments were sampled at the Hwangdo tidal flat and adjacent sea in June and October 2003. The surface sediments consisted of five sedimentary facies. Generally, the surface sediments in October were changed coarser on the tidal flat and little changed in the subtidal area compared to those in June 2003. Sedimentary facies analysis of three core sediments suggested that wave and tidal current were relatively strong in the tidal flat near Hwangdo, whereas the energy was relatively low in the tidal flat near channel. Sediment accumulation rates in the Hwangdo tidal flat during 11 months indicated that sediments deposited in the central part, whereas eroded in eastern and western sides of the tidal flat. These caused that sea dike changed tidal current patterns and sediment supplies.

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Thickness Measure and Characteristic Length for Effective Young's Modulus of Model Ice Plate in the Ice Basin (빙해수조 모형빙판의 두께 계측과 유효탄성계수용 특성길이 연구)

  • Lee, Jae-Hwan;Choi, Bong-Kyun;Lee, Chun-Ju
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.5
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    • pp.353-360
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    • 2014
  • The model ice is created at KRISO (Korea Research Institute for Ships and Ocean Engineering) ice basin where model ship is tested to obtain the necessary data in order to design the ice breaking vessels and ocean structures operating in the northern pole sea area. Through the model ship test, ice breaking, clearing, ice-ship and ice-propeller interaction behavior can be obtained. Since mechanical properties of ice plate are required for the model test, some tests are performed to obtain the properties in this paper. First, ultrasonic devide is used to measure the thickness of the model ice plate and the results show the possibility of using ultrasonic method, yet more sophisticated device or special sensors are required to measure the ice thickness completely. And the defection of ice plate is measured using LVDT to compute the characteristic length of ice plate on the fluid, which is used to get the effective Young's modulus of model ice.

Patterns in solute chemistry of six inlet streams to Lake Hövsgöl, Mongolia

  • Puntsag, Tamir;Owen, Jeffrey S.;Mitchell, Myron J.;Goulden, Clyde E.;McHale, Patrick J.
    • Journal of Ecology and Environment
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    • v.33 no.4
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    • pp.289-298
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    • 2010
  • A number of characteristics of the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed, such as the lake's location at the edge of the Central Asian continuous permafrost zone, provide a unique opportunity to evaluate possible anthropogenic impacts in this remote area in northern Mongolia. In this study, we compared stream solute concentrations in six sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed. Water samples were collected during the summer months between 2003 and 2005. Concentrations of $Cl^-$ ranged from 9.8 to $51.3\;{\mu}mol/L$; average nitrate concentrations were very low and ranged from undetectable to $1.1\;{\mu}mol/L$ and average ${SO_4}^{2-}$ concentration at sampling stations with minimal animal grazing ranged from 66 to $294\;{\mu}mol/L$. Average dissolved organic carbon (DOC) concentrations ranged from 642 to $1,180\;{\mu}mol$ C/L. We did not find statistically significant differences in DOC concentrations among the six streams, although DOC concentrations tended to be higher in the two northernmost streams, possibly related to differences in the active layer above the permafrost. Dissolved organic nitrogen (DON) concentrations were correlated with DOC concentration, and followed the same spatial pattern as those for DOC. In streams in this remote watershed, total dissolved nitrogen was made up of mostly organic N, as has been found for other regions distant from anthropogenic N sources. Overall, these results suggest that future research on the dynamics of DOC and DON in this watershed will be especially insightful in helping to understand how changes in climate and land use patterns will affect transformations, retention, and export of dissolved organic matter within these sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l region.

A Study on Core Values of University Libraries through Missions and Visions (사명, 비전을 통해 본 대학도서관의 핵심 가치)

  • Cho Yoon-Hee
    • Journal of the Korean Society for Library and Information Science
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    • v.39 no.4
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    • pp.71-98
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    • 2005
  • Recently, the speed of changes surrounding university libraries requires a hybrid library environment that supports integrated services, combining a virtual space with physical space of traditional libraries. Through changes, university libraries have faced the need to review their missions and visions, laying stress on the core values of university libraries. This study analyzed the central keywords in the contents of mission and vision statements of university libraries in America, England, Canada, and Australia. The research was acquired from mission and vision statements containing core values of developed university libraries. Core values are present in each area such as correction and information resources, services, place, people, environment and infrastructure, community, and parent-university relations. Ultimately, this study tried to provide the directions and the basic materials for the establishment of missions and visions for university libraries in Korea.

Study on The Contact Metamorphism of Weolagsan Granite (월악산화강암(月岳山花崗岩)의 접촉변성(接觸變成)에 관(關)하여)

  • Lee, Dai Sung;Kang, Jun Nam
    • Economic and Environmental Geology
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    • v.11 no.4
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    • pp.169-182
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    • 1978
  • The Weolagsan area consists of four units; (1) Low grade meta-sediments of the upper members of Ogcheon age unknown group such as Changri (mainly black slate and phyllitic rock), Majeonri (mainly alternation of slate, limestone and chert) and Hwanggangri Formation (pebble bearing phyllitic sediments); (2) Samtaesan Formation of Chosun System of Ordovician; (3) So called meta-volcanics and (4) Weolagsan Granite and its associations which intruded above mentioned meta-sediments and meta-volcanics. This study was focused to know the Woelagsan granite and its metasomatic effects to the country rocks petrographically and petrochemically. According to the field survey, microscopic work and some chemical analysis, the granite is a "normal granite" based on the Streckeisen's classification and belongs to a mass of the Central-zone younger group in Ogcheon geosynclinal belt. The granite metasomatized the country rocks along its northern contact zone. Zone of calcareous and cherty rocks (Majeonri formation) was silicified partly and skarned locally at the contact with the granite. The chemical analysis of the zone show no difinite variations in contents of $SiO_2$ and CaO with the distance from the granite. It seems to be indicated that the silicification of this part was not so metasomatized by the granite body, but thermally affected as much as to be partially remelted in the specific parts of the formations. Meta-volcanic rock zone was slightly chloritized near contact with the granite. Limestone of Samtaesan Formation was silicified and skarned along the contact zone by the granite body. The chemical analysis of the zone show some noticiable changes in compositions of $SiO_2$ and CaO with distance from the granite boundary. It can be imagined that the silicification of this zone was metasomatically originated by Woelagsan Granite. According to chemical analysis on several trace elements, the ratio of Zn/Cr and Ni/Cr are relatively higher than that of Cu/Cr in the above mentioned silicified zones. Generally the variation of these metal elements in the zones tend to be regular with distance from the granite body.

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Numerical Simulation of the Effects of Moisture on the Reinforcement of a Tropopause Fold

  • Lee, Hong-Ran;Kim, Kyung-Eak;Lee, Yong-Hee
    • Journal of the Korean earth science society
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    • v.30 no.5
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    • pp.630-645
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    • 2009
  • The tropopause fold event that took place on January 1, 1997 over mid-region on the Korean Peninsula is examined by means of a numerical simulation based on a Mesoscale Model (MM5). The purpose of this paper is to investigate the effects of moisture in reinforcing a tropopause fold linked to an explosive cyclone. Two types of simulations were carried out; 1) simulations for moist conditions in which full physical and dynamic processes are considered and 2) simulations for dry conditions in which cumulus parameterization and cloud microphysics process are excluded. The results of the moist condition simulations demonstrate that the intensity of the central pressure of the cyclone was overestimated compared with the observed values and that the location of the center and the pressure deepening rates (-17 hPa/12 hr) complied with the observed values. The potential vorticity (PV) anomaly on the isentropic surface at 305 K continued to move in a southeast direction on January 1, 1997 and thus created a single tube of tropopause fold covering the northern and the middle area of the Korean Peninsula and reaching the ground surface at 0300 UTC and 0600 UTC. The results of the dry condition simulations show that the tropopause descended to 500 and 670 hPa in 0300 and 0600 UTC, respectively at the same location for the moist condition simulation; however, there was no deep tropopause fold observed. A comparison of the simulated data between the moist and the dry conditions suggests that a deep tropopause fold should happen when there is sufficient moist in the atmosphere and significantly large PV in the lower atmosphere pulls down the upper atmosphere rather than when the tropopause descends itself due to dynamic causes. Thus, it is estimated that moisture in the atmosphere should have played a crucial role in a deep tropopause fold process.

Seroprevalence of Coxiella burnetii in bulk-tank milk and dairy cattle in Gyeongbuk province, Korea (경북지역 집합유와 젖소에서 큐열 항체 보유율 조사)

  • Ouh, In-Ohk;Seo, Min-Goo;Do, Jae-Cheul;Kim, In-Kyoung;Cho, Min-Hee;Kwak, Dong-Mi
    • Korean Journal of Veterinary Service
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    • v.36 no.4
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    • pp.243-248
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    • 2013
  • Q fever is a rickettsial infection caused by Coxiella burnetii that is transmitted from animals to humans. Modes of transmission to humans include inhalation, tick bites and ingestion of unpasteurized milk or dairy products. This survey was aimed at monitoring the seroprevalence of C. burnetii in bulk-tank milk (BTM) in Gyeongbuk province. In addition, the seroprevalence of C. burnetii was investigated at the herd level of dairy cattle in eastern Gyeongbuk province in which many dairy cattle are reared. Among 324 BTM samples collected from 20 country areas, 175 (54%) BTM samples from 15 (75%) country areas were positive for C. burnetii by ELISA. By regions, the seroprevalence of BTM samples in eastern, central, western and northern areas of Gyeongbuk province were 62.7%, 48.4%, 45.1%, and 41.4%, respectively. When analyzed in the dairy cattle reared in the eastern area where high seroprevalence occurred in BTM samples, 119 (24.2%) out of 492 dairy cattle were positive for C. burnetii. Seroprevalence of C. burnetii in dairy cattle was increased with daily milk yield of farm (P<0.05) and age (P<0.001). Since seroprevalence of C. burnetii is relatively high in both BTM samples and dairy cattle reared in Gyeongbuk province, further studies on the high risk farms and herds are needed to evaluate infection status and appropriate control programs in this region.