• 제목/요약/키워드: environmental history

검색결과 1,257건 처리시간 0.032초

Tectonics, sedimentation, and magmatism of the Cretaceous Gyeongsang (Kyongsang) Basin, Korea: Integrated approach to defining basin history and event mineralization

  • Chang, Ryu-In;Park, Seon-Gyu;Meen, Wee-Soo;Lee, Sang-Yeol
    • 대한자원환경지질학회:학술대회논문집
    • /
    • 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
    • /
    • pp.27-31
    • /
    • 2003
  • During the past decade, integrated stratigraphy has been effectively applied to many sedimentary basins to analyze stratigraphic response to tectonic evolution. This application has been beneficial to hydrocarbon exploration in the basins because it provides a better understanding of temporal and spatial relationships of hydrocarbon source and reservoir rocks as a function of basin evolution. Like the maturation, migration, and trapping of hydrocarbons, ore-forming processes in hydrothermal deposits may be causally linked to particular phases of basin evolution. Consequently, applying integrated stratigraphy to mineral exploration may be a logical and helpful approach to understanding ore-forming processes and predicting their occurrence, location, and origin. (omitted)

  • PDF

강릉지역 초등학생들의 폐기능과 영향 요인 분석 (Pulmonary Function and Its Influence Factors of Elementary School Children in Gangneung)

  • 유승도;유시은;이민정;최욱희;김대선;이철호;박경화
    • 한국환경보건학회지
    • /
    • 제34권1호
    • /
    • pp.20-26
    • /
    • 2008
  • The objective of the study which utilised population based data was to determine the respiratory condition of elementary school children in Gangneung. From October 9th to December 14th, 2006, Pulmonary Function Tests (PFT) including Forced Vital Capacity (FVC) and Forced Expiratoy Volume in I Second $(FEV_1)$ were conducted on the target group of children using a spirometer. The prevalence of asthmatic symptoms was 29.8% among boys and 39.6% among girls. By using logistic regression, we found that family history of allergic rhinitis (OR=3.90, CI=1.05-14.51), experience of allergic conjunctivitis (OR=4.67, CI=1.54-14.16) and atopic dermatitis (OR=2.86, CI=1.17-7.05) significantly increased the asthmatic symptoms. Also, a family history of asthma and food allergy were associated with asthmatic symptoms. In relation to housing and environmental risk factors, residences under the ground (OR=3.59, CI=1.35-9.51) and big-size dolls (OR=2.71, CI=0.86-8.53) significantly increased the prevalence of asthmatic symptoms. For PFT, above four families, exposure of passive smoking and pets significantly reduced FVC in both groups (p<0.05). In girls, a big-size doll was significantly associated with decreased lung function (FVC and $FEV_1$). In boys, using bed significantly reduced $FEV_1$. Also, the risk of asthmatic symptoms was found to increase when the house has been built for 5 years or more, the house is close to a road $({\leq}100m)$, a gas/Kerosene heater or carpet is utilized within the house. However, their differences were not significant. It is concluded that genetic factor such as a family history of respiratory disease, allergic symptoms and housing risk factor are related to asthmatic symptoms. These results were worth noting because the findings will help address risk factors related respiratory symptoms especially in relation to housing and environment.

Research history of Nannophya Rambur(Odonata: Libellulidae): A recently discovered species in addition to Nannophya koreana Bae in Korea

  • Kim, Dong Gun
    • 환경생물
    • /
    • 제38권2호
    • /
    • pp.308-314
    • /
    • 2020
  • The Nannophya species in Korea was thought to consist of only Nannophya pygmaea. Previous studies on the species, including life history and development, conservation and restoration, habitat characteristics, genetic studies, distribution, behavior, and taxonomy have been conducted. However, a new Nannophya species, Nannophya koreana, was recently discovered in Korea. Moreover, this new species was found to inhabit both Korea and Japan. Thus, the previous studies should be reevaluated in relation to the new species, Nannophya koreana, and the latter should be treated as an endangered species worldwide given the current population instability.

아파트 옥외공간의 조경 변천에 관한 연구 - 법규와 법조문의 변화를 중심으로 - (The History of Transformation of Outdoor Landscape in Apartment Complex - Focused on the Enactment and Revision of laws and Regulations -)

  • 김대현
    • 한국환경복원기술학회지
    • /
    • 제6권2호
    • /
    • pp.39-47
    • /
    • 2003
  • This research traces the history of legislative matters regarding the enactment and revision of laws and regulations related to the outdoor landscape in apartment complex. The years before 1976 can be classified as 'a period of darkness' for the landscape in apartment complex due to absence of landscape legislation. From the year of 1977 when the landscape planting and mere necessities were carried out according to the local administration's building standard to the year of 1990 can be classified as 'a period of quickening'. The year of after 1991 when the enactment of the code#32 called "the green space in site" in the "Korea Building Code" and the "Korea Housing Standard & Regulation" was made, and various construction regulations and provisions were revised in order to improve the scantiness of the apartment complex and its environment should be called 'a period of development'.

Residual drift analyses of realistic self-centering concrete wall systems

  • Henry, Richard S.;Sritharan, Sri;Ingham, Jason M.
    • Earthquakes and Structures
    • /
    • 제10권2호
    • /
    • pp.409-428
    • /
    • 2016
  • To realise the full benefits of a self-centering seismic resilient system, the designer must ensure that the entire structure does indeed re-center following an earthquake. The idealised flag-shaped hysteresis response that is often used to define the cyclic behaviour of self-centering concrete systems seldom exists and the residual drift of a building subjected to an earthquake is dependent on the realistic cyclic hysteresis response as well as the dynamic loading history. Current methods that are used to ensure that re-centering is achieved during the design of self-centering concrete systems are presented, and a series of cyclic analyses are used to demonstrate the flaws in these current procedures, even when idealised hysteresis models were used. Furthermore, results are presented for 350 time-history analyses that were performed to investigate the expected residual drift of an example self-centering concrete wall system during an earthquake. Based upon the results of these time-history analyses it was concluded that due to dynamic shake-down the residual drifts at the conclusion of the ground motion were significantly less than the maximum possible residual drifts that were observed from the cyclic hysteresis response, and were below acceptable residual drift performance limits established for seismic resilient structures. To estimate the effect of the dynamic shakedown, a residual drift ratio was defined that can be implemented during the design process to ensure that residual drift performance targets are achieved for self-centering concrete wall systems.

Recent Vegetation History and Environmental Changes in Wangdeungjae Moor of Mt. Jiri

  • Kim, Jae-Geun;Lee, Yang-Woo
    • The Korean Journal of Ecology
    • /
    • 제28권3호
    • /
    • pp.121-127
    • /
    • 2005
  • To reveal vegetation history and environmental changes in Mt. Jiri, sediment cores were collected from Wangdeungjae moor of Mt. Jiri. Overall dry matter accumulation rates and sedimentation rates by $^{14}C-dating$ were 0.027 $kg{\cdot}m^{-2}{\cdot}yr^{-1}$ and 0.184 mm/yr since 1250 ($760{\pm}40$ yrs BP, 14 cm in depth). There are three pollen zones; the first zone is below 14 cm depth where Quercus dominated, the second zone is from 14 cm to 6 cm depth where Gramineae increased and Quercus and Salix dominated and the third zone is from 6 cm depth to the top where Pinus and Quercus dominated. Total pollen concentration gradually increased from bottom to the top of sediment core, which implies wet, anaerobic and cool condition during covered period by the core. Calcium and magnesium contents had increased since 14 cm depth, with peaks at 13 and 20 cm depths. This indicates that groundwater had recently become relatively more important than surface water as water source of Wangdeungjae moor Exotic plant or Chenopodiacea pollen was less than 1%. There was little variation in total N and P contents along the length of the core. These results support that Wangdeungjae moor has been little affected by anthropogenic activities. Also, nutrients and heavy metal contents indicate the baseline condition of Wangdeungjae moor.

Time history analysis of a tensile fabric structure subjected to different seismic recordings

  • Valdes-Vazquez, Jesus G.;Garcia-Soto, Adrian D.;Chiumenti, Michele;Hernandez-Martinez, Alejandro
    • Earthquakes and Structures
    • /
    • 제20권2호
    • /
    • pp.161-173
    • /
    • 2021
  • The structural behavior of a tensile fabric structure, known as hypar, is investigated. Seismic-induced stresses in the fabric and axial forces in masts and cables are obtained using accelerograms recorded at different regions of the world. Time-history analysis using each recording are performed for the hypar by using finite element simulation. It is found that while the seismic stresses in the fabric are not critical for design, the seismic tensile forces in cables and the seismic compressive forces in masts should not be disregarded by designers. This is important, because the seismic design is usually not considered so relevant, as compared for instance with wind design, for these types ofstructures. The most relevant findings of this study are: 1) dynamic axial forces can have an increase of up to twice the static loading when the TFS is subjected to seismic demands, 2) large peak ground accelerations seem to be the key parameter for significant seismic-induced axial forces, but not clear trend is found to relate such forces with earthquakes and site characteristics and, 3) the inclusion or exclusion of the form-finding in the analysis procedure importantly affects results ofseismic stresses in the fabric, but not in the frame.

응력이력이 사질토의 CPT-DMT 상관관계에 미치는 영향 (Effect of Stress History on CPT-DMT Correlations in Granular Soil)

  • 이문주;최성근;김민태;이주형;이우진
    • 한국지반공학회논문집
    • /
    • 제26권7호
    • /
    • pp.7-16
    • /
    • 2010
  • 응력이력은 사질토 지반의 잔류 수평응력을 증가시켜 현장시험의 관입저항을 증가시킨다. 본 연구에서는 챔버에 조성된 정규 및 과압밀 시료에 대한 콘관입시험과 딜라토미터 시험을 수행하고 응력이력이 시험결과와 측정값의 상관관계에 미치는 영향을 분석하였다. 시험결과, 평균 유효응력으로 정규화된 콘선단저항은 상대밀도 및 상태정수와 높은 상관성을 보였다. 딜라토미터의 수평응력지수($K_D$)는 콘선단저항($q_c$) 뿐만 아니라, 딜라토미터 계수($E_D$) 보다도 응력이력 영향을 효과적으로 반영하였다. 수평응력지수에 반영된 응력이력의 영향을 정지토압계수인 $K_0$로 보정한 $K_D/K_0$는 상대밀도 뿐만 아니라, 상태정수, 평균 유효응력으로 정규화된 콘선단저항과 응력이력에 관계없는 높은 상관성을 보였다. 또한 평균 유효응력으로 정규화된 딜라토미터 계수($E_D/{\sigma}_m'$)와 상태정수의 관계도 응력이력에 관계없이 유일한 식으로 표현되었다.