• Title/Summary/Keyword: 사구

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Applicability of Wind-Vegetation Model in Small Scale Sand Dunes (소규모 사구 지역 바람-식생모델 적용성 분석)

  • Choi, Seok Keun;Choi, Jae Wan;Park, Sang Wook;Jung, Sung Heuk;Lee, Soung Ki
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.6
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    • pp.545-552
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    • 2017
  • Aeolian dunes are typical sand dunes which are maintained and developed by interactions of earth surface, wind and vegetation. Developing a model which can predict the changing phenomena of these sand dunes is vital in enhancing the efficiency of understanding and management of terrains such as land degradation. In the existing models, however, there is lack of studies on the long - term behaviors of the sand dunes and application to actual topography. Therefore, this study applied the wind-vegetation model considering vegetation to the actual topography and analyzed the applicability of the wind-vegetation model by analyzing the long-term behaviors and comparing them with actual data. Through analysis, study found out that use of wind-vegetation model and data from unmanned aerial vehicle is effective in analyzing the changes of actual dune topography. Except for the boundary, the error of about 1m was generated compared with the change of the actual dune topography.

A Case of Focal Segmental Membranoproliferative Glomerulonephritis in a 5 Years Old Girl (5세 여아에서 발견된 초점분절 막증식사구체신염 1례)

  • Song Jun Ho;Kim Young Bin;Eun Lucy Young Min;Song Ji Sun;Jeong Hyeon Joo;Kim Pyung Kil
    • Childhood Kidney Diseases
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    • v.9 no.2
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    • pp.237-244
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    • 2005
  • Membranoproliferative glomerulonephritis (MPGN) is a progressive primary glomerulonephritis characterized by mesangial proliferation with increased mesangial matrix, subendothelial immune deposits, mesangial interposition and a double contour feature of the glomerular basement membrane. The glomerular involvement in MPGN is usually diffuse, however, cases of focal or segmental MPGN have been reported by several authors. We report a case of focal segmental MPGN with prolonged hypocomplementemia for ,3 years in a 5 years old girl. (J Korean Soc Pediatr Nephrol 2005;9:237-244)

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A Luminescence Dating for a Relict Dune from the Sindu Dunefield (신두리 지역의 고사구(古砂丘)에 대한 OSL 연대 측정)

  • Seo, Jong-Cheol
    • Journal of the Korean association of regional geographers
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    • v.11 no.1
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    • pp.114-122
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    • 2005
  • To find out the buried age of the relict dune sediments, a luminescence dating bas conducted for a relict dune from the Sindu dunefield on the Taean Peninsula. It shows that the deposition of the dune sands at 3m depth began about 690$\sim$730 years ago. From 3m to l.5m depth, the lower part of the dune bas remained stable, but a relict dune deposit appear at 1.3m depth. This part yields an age of about 68 years. The two samples that were collected from the lower part of the dune at depths of the 1.5 m and 3.0 m below the surface show a net accumulation rate of around 0.75 cm/y which is relatively slow for a coastal dune. The chronology obtained in this study demonstrates that a significant amount of sediments has been replaced or remobilized in the area over the past 1000 years, and there was at least a soil formation process during the same time period. These suggest that a new approach is necessary to identify the formation age of the so-called paleo-dune at the Sind dunefield.

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A Study of the Lipid Components in Egg Yolk Oil (난황유의 지질성분에 관한 연구)

  • 김종숙;고무석;최옥자
    • Korean journal of food and cookery science
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    • v.12 no.3
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    • pp.295-299
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    • 1996
  • Egg yolk oil was obtained from a roasting and Pressure egg yolks obtained from cage system, open barn system, respectively. Lipids in egg yolk oil were extracted with a mixture of chroform: methanol (2:1, v/v) and fractionated into neutral lipid, glycolipid and phospholipid by silicic aicd column chromatography. Lipid components of each fraction were determined by thin layer chromatography (TLC). The results were sum- marized as follows: lipid content of egg yolk from each cage system (A) and open barn system (B) was 31. 05% and 33.34%, and the lipid is made up of neutral lipid 76.60%, 71.23%, glycolipid 3.95%, 5.03% and phospholipids 19.45%, 23.74% respectively. Triglycerides (A: 59.3%, B: 56.3%) were the major components among the neutral lipids; monoglycerides, diglycerides, free sterols, and free fatty acids were the minor cop- monents. The major components of the glycolipids were digalactosyl diglycerides (A: 98.3%, B: 97.8%), the other components were cerebrosides. The major components of the phophoslipids were phosphatidyl choline plus phosphatidyl serine (A: 58.6%, B: 59.8%) the other components were lecithin plus sphingomyelin.

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The Viticetea rotundifoliae in South Korea and Japan (한국과 일본의 순비기나무군강)

  • Jung, Yong-Kyoo
    • The Korean Journal of Ecology
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    • v.23 no.5
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    • pp.383-389
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    • 2000
  • A comparative analysis on the Viticetea rotundifoliae (coastal dune shrub vegetation) in South Korea and Japan was carried out. 569 releves from the most typical and homogeneous stands of the coastal dunes in South Korea and Japan were used. This study was accomplished by using the syntaxa and hierarchical system of the Viticetea rotundifoliae in South Korea and Japan according to the Zurich-Montpellier School's method, and syntaxonomy, synecology, syndynamics and syngeography between two countries were also compared with. Coastal dune shrub vegetation in South Korea and Japan were defined to the Viticetea rotundifoliae representing southern type coastal shrub in Northeast Asia. Coastal dune shrub communities of the Viticetea rotundifoliae in South Korea and Japan are considerably corresponded between the two, and contain their own characteristic syntaxa. Coastal dune shrub communities of the Viticetea rotundifoliae in Japan showed much diversification in syntaxa and species composition than those in South Korea.

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Analysis of the Change of the Flora and Vegetation Association of Ui Island Sand Dune (우이도 해안사구의 식물상과 식생군집 변화분석)

  • Beon, Mu-Sup;Oh, Hyun-Kyung
    • Korean Journal of Environment and Ecology
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    • v.20 no.1
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    • pp.41-51
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    • 2006
  • We investigated the flora of Ui Island sand dunes, consisting of 142 taxa; 52 families, 108 genera, 124 species, 15 varieties, and 3 forms. The total plants of floral region that were identified were 16 taxa; Elymus mollis, Salsola collina, and Farfugium japonicum in Class III; Ischaemum anthephephoroides, Carex kobomugi, Glehnia littoralis, Messerschmidia sibirica, Machilus thunbergii, Elaeagnus macrophylla, and Aster spathulifolius in Class I . Naturalized plants were 11 taxa; 7 families, 10 genera and the naturalization degree was 7.8%. On the Donmok seaside area, the coverage rate was about $20%{\sim}25%$ in 2002, but this time it had increased to more than three times or $65%{\sim}75%$. Also, on the Sungchon seaside area, the coverage rate was about $15%{\sim}20%$ in 2002, but this time it was $70%{\sim}75%$ as a result of the rapid increase of Zoysia macrostachya and Carex kobomugi. Pungseong sand dune area showed a monotonous state in variety and number, because of the strong wind and repetition of sand income and outcome.

A study on the characteristics and geomorphic process of sand dunes at the lower reach of the Duman river, Korea and China (두만강 하류 사구지형의 특징과 형성과정에 관한 연구)

  • Zhu, Zhe;Lee, Min-Boo
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.1
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    • pp.29-40
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    • 2012
  • The sand dunes at the lower reach of the Duman river indicate that their distribution patterns and directions conform to the dominant northwestern winter wind. On the riverbed of the Duman river at the surroundings of sand dunes form sandy point bars and mid-stream islands. The geomorphic processes of sand dunes can be classified into two types according to the depositional environments via analyses of the sand grain size and stratigraphic profiles. First, the sand dunes of Hoelyongbong, Kyeongshin-Wonjeong, and the riverside areas of the Duman river, have formed by alluvium of the Duman river which deposits and accumulates on the riverbed, then being wind blown to the nearby sand bars, terraces and higher eroded hills. The second type is the active sand dune of the Bangcheon-Nodongja District which develops similarly as to the formation of the first type, but the fixed sand dunes of the district seem to have formed in the underwater condition.

Numerical simulation of sand dunes using three-dimensional numerical model (3차원 수치모형을 이용한 사구발달 수치모의)

  • Kim, Hyung Suk;Park, Moon Hyung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.281-281
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    • 2017
  • 하천에서 하도불안정(stream instability)으로 인하여 하상의 형태가 변화하고 하상파(sand wave)가 발생한다. 사련(ripple), 사구(dune) 등과 같은 하상파는 흐름저항을 유발하여 홍수시 수위를 증가시킨다. 수리실험 및 수치모형을 이용하여 사련 및 사구의 발달과정 그리고 이를 지나는 난류흐름에 대한 연구가 국외에서는 이루어지고 있지만 국내의 경우 거의 찾아보기 힘들다. 수치모형을 활용한 연구는 주로 횡방향으로 하상파가 일정하다는 가정하에 연직 2차원 수치모형을 적용하였으나 최근 컴퓨터 기술 및 수치기법의 고도화로 3차원 RANS(Reynolds averaged Navier-Stokes) 또는 LES(Large eddy simulation)를 이용한 수치모형이 개발되고 있다. 본 연구에서는 LES에 유사이송 및 하상변동 모형과 결합하여 사구발달에 대한 수치모의를 수행하였다. LES와 유사이송 및 하상변동 모형의 결합은 순간유속성분을 하상변동모형에 직접 적용되기 때문에 난류영향을 고려할 수 있는 것이 장점이다. 특히 사구의 발달에 따라 복잡한 흐름이 발생하며 3차원 와구조가 발생하므로 난류특성의 고려는 필수적이다. 수치모의는 Delft Hydraulics (Bakker et al., 1986)에서 수행한 수리실험 T39를 활용하였다. 수리실험은 길이 100 m, 폭 0.5 m 개수로에서 수행되었으며 평균유속은 0.611 m/s, 수심은 0.436 m이다. 하상파 실험에 사용된 유사입경은 0.78 mm 균일사를 사용하였다. 수치모의 조건은 수리실험과 동일하게 하였으나 계산시간의 효율을 고려하여 흐름방향의 계산영역은 4.0 m로 하고 주기경계조건(periodic boundary condition)을 부여하여 계산을 수행하였다. 수치모의 계산은 사구의 길이 및 파고가 평형상태에 이를 때까지 수행되었다. 수치모의 통해 사구발달에 따른 흐름 및 하상변동 특성을 분석하였다.

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Glomus Tumor in Soft Tissue (연부 조직에 발생한 사구종)

  • Kim, Do-Yeon;Lee, Soo-Hyun;Kim, Min-Ju;Shin, Kyoo-Ho
    • The Journal of the Korean bone and joint tumor society
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    • v.15 no.1
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    • pp.34-43
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    • 2009
  • Purpose: Glomus tumors are rare benign vascular tumors, usually located in the skin or soft tissue of extremities. Approximately 30-50% of glomus tumors occur in subungal area, but glomus tumors have been described in every location even where glomus bodies are not or rarely present. The purpose of this study was to identify clinical, histologic and MRI characteristics of soft tissue glomus tumor. Materials and Methods: Between 1993 and 2008, eight patients underwent surgery of soft tissue Glomus tumor at our institution. Exclusion criteria were patients with Glomus tumors in digits, stomach, trachea and glomus tympanicum. We analyzed medical records, interviews, physical examinations, MR findings and histolocial types retrospectively. Results: There were four men and four women. The mean age was fourty-seven years. The mean prevalence time was eight-point-nine years. In the classic triad of symptoms, all eight patients had pain and tenderness. Two patients complained of cold sensitivity. Two showed skin color changes. After surgery, two showed symptom improvement (VAS $9^{\circ}{\rightarrow}8$, $8^{\circ}{\rightarrow}5$) and?six showed complete disappearance of symptoms. Slightly symptom improvemented (VAS $9^{\circ}{\rightarrow}8$) one had additional surgery two times after first surgery due to relapse/remaining Glomus tumor. The mean size was 13.9 mm. In histology, six were 'solid glomus tumor', one was a mixture of 'solid glomus tumor' and 'lomangioma' and one was 'malignant glomus tumor'. MR findings showed isointense signal on T1 image, high signal on T2 image and strong enhancement on the Gadolinium enhanced image. Conclusion: Glomus tumor has low recurrence rate and malignant change, rapid diagnosis and surgical excision is critical in treatment to prevent unnecessary pain of patient.

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Relationship of Glomerular Basement Membrane Alterations to Epithelial Cell Structure and Clinical Parameters in Alport Syndrome (Alport 증후군에서 사구체 기저막의 형태학적 변화와 사구체 상피세포의 구조 및 임상지표와의 관계)

  • Eom, Hye-Jin;Hong, Seung-Jin;Lee, Jae-Seung;Jeong, Hyeon-Joo;Kim, Young-Ki;Kim, Kee-Hyuck
    • Childhood Kidney Diseases
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    • v.14 no.1
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    • pp.22-31
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    • 2010
  • Purpose : This study was performed to evaluate the relationship between glomerular basement membrane (GBM) alterations to epithelial cell (EpC) structure and renal function in Alport Syndrome (AS) patients. Methods : Fifteen patients diagnosed with AS (4-26yrs) were examined. The GBM in AS was categorized as : C1) normal, C2) minor alterations (widening of lamina rara interna or externa without lamina densa change), C3) nonspecific splitting of lamina densa, C4) basket-weaving pattern of lamina densa splitting. The length of each GBM portion along the epithelial side was measured on the systematically obtained electron microscopic photographs. Furthermore to obtain an objective assessment of the degree of glomerular EpC foot process change, the number of slit pores along $10\;{\mu}m$ of peripheral GBM in each category was obtained. Results : The percentage of normal GBM portion (C1) correlated inversely with daily protein excretion (g/day/$m^2$, P<0.05) and sum of the percentage of abnormal GBM portion (C2+C3+C4) had direct correlation with daily protein excretion (g/day/$m^2$, P<0.05). There were no significant relationships between the percentages of other categories of GBM alterations and creatinine clearance or protein excretion. There were no significant relationships between of creatinine clearance in relation to normal GBM(C1) portion as well as that in relation to sum of the percentage of abnormal GBM portion (C2+C3+C4). GBM abnormality did not correlate with age at biopsy. Conclusion : The extent of GBM structural abnormality is related to proteinuria in AS but the epithelial response is uniform even though the GBM ultrastructural lesions are not.