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옥천대 흑색셰일 및 점판암 분포지역 암석-토양-농작물 시스템에서의 As및 관련 원소들의 분산과 이동
이지민,전효택 대한자원환경지질학회 2003 자원환경지질 Vol.36 No.4
The Dukpyung and the Chubu areas were selected to investigate the migration and enrichment of arsenic and other toxic elements in soils and crop plants in areas covered with black shales. Rock and soil samples digested in 4-acid solution (HCI+HNO$_3$+HF+HC1O$_4$) were analyzed fer arsenic and other heavy metals by ICP-AES and ICP-MS, and plant samples by INAA. Mean concentration of As in Okchon black shale is higher than those of both world average values of shale and black shale. Especially high concentration of 23.2 mg/kg As is found in black shale from the Dukpyung area. Mean concentration of As is highly elevated in agricultural soils from the Duk-pyung (28.2 mg/kg) and the Chubu areas (32.6 mg/kg). Arsenic is highly elevated in rice stalks and leaves from the Dukpyung (1.14 mg/kg) and the Chubu areas (1.35 mg/kg). The biological absorption coefficient (BAC) of As in plant species decreases in the order of rice leaves>com leaves>red pepper>soybean leaves=sesame leaves>corn stalks>corn grains.
이지민,이진수,전효택 대한자원환경지질학회 2003 자원환경지질 Vol.36 No.6
The objectives of this study are (1) to determine the extent and degree of As contamination of the water and sediments influenced by mining activity of the abandoned Au-Ag mines, (2) to examine As speciation In contaminated water, (3) to monitor variation of As contamination in water system throughout the dry and wet seasons, and (4) to investigate the As chemical form in the sediments through the sequential extraction analyses. Natural water(mine water, surface water and groundwater) and sediments were collected in six abandoned Au-Ag mine(Au-bearing quartz veins) areas. The contamination level of As in mine water of the Dongil(524${\mu}m$/L) is more higher than the tolerance level(500 ${\mu}m$/L) for waste water of mine area in Korea. Elevated levels of As in stream water were also found in the Dongil(range of 63.7∼117.6 ${\mu}m$/L.) and Gubong(range of 56.1∼62.9 ${\mu}m$/L) mine areas. Arsenic contamination levels in groundwater used by drinking water were more significant in the Dongil(11.3∼63.5 ${\mu}m$/L), Okdong(0.2∼68.9 ${\mu}m$/L) and Gubong(2.0∼101.0${\mu}m$/L) mine areas. Arsenate[As(V), $H_2AsO_4^-$] is more dominant than arsenite[As(III), $H_3AsO_3$] in water system of the most mine areas. The concentration ratios of As(III) to As(total), however, extend to the 95% in stream water of the Okdong mine area and 70∼82% in groundwater of the Okdong and Dongjung mine areas. As a study of seasonal variation in the water system, relatively high levels of As from the dongil mine area were found in April rather than in September. Sequential extraction analysis showed that As was predominantly present as coprecipitated with Fe hydroxides from sediment samples of the Dongjung and Gubong mine(35.9∼40.5%), which indicates its possibility of re-extraction and inducing elevated contamination of As in the reductive condition. In sediments from the Dongil, Okdong and Hwachon mine area, high percentage(55.2∼83.4%) of As sulfide form was found.
계통 접속 조건을 고려한 해상풍력단지 무효전력 최적 보상 연구v
이지민,이규섭 대한전기학회 2025 전기학회논문지 Vol.74 No.6
Large-scale offshore wind power systems are regarded as a key solution for achieving carbon neutrality due to their advantages in public acceptance and efficiency. While wind power technology continues to advance rapidly, there remains a lack of research focused on analyzing grid codes such as voltage ride through, and reactive power capability and power system planning to meet those standards in terms of offshore wind farm integration. This paper proposes an optimization-based method for determining the optimal capacity of reactive power compensation equipment to satisfy the reactive power capability requirements specified in grid codes for offshore wind power integration systems. A test system representing an offshore wind farm is implemented to validate the proposed approach and derive the optimal capacities of the compensation equipment. ㅍ Large-scale offshore wind power systems are regarded as a key solution for achieving carbon neutrality due to their advantages in public acceptance and efficiency. While wind power technology continues to advance rapidly, there remains a lack of research focused on analyzing grid codes such as voltage ride through, and reactive power capability and power system planning to meet those standards in terms of offshore wind farm integration. This paper proposes an optimization-based method for determining the optimal capacity of reactive power compensation equipment to satisfy the reactive power capability requirements specified in grid codes for offshore wind power integration systems. A test system representing an offshore wind farm is implemented to validate the proposed approach and derive the optimal capacities of the compensation equipment.
알쯔하이머형 치매 환자에서 행동심리증상과 호모시스테인과의 연관
이지민,임우영,김현,이강준,Lee, Ji Min,Im, Woo-Young,Kim, Hyun,Lee, Kang Joon 한국정신신체의학회 2014 정신신체의학 Vol.22 No.1
Objectives : Homocysteine has been associated with cognitive impairment and various psychiatric symptoms. This study was designed to examine the relationship exists between plasma homocysteine concentration and behavioral and psychological symptoms of dementia(BPSD). Methods : 41 subjects with dementia of Alzheimer's type were included in this study. We carried out history taking, physical examination, and cognitive assessment for the diagnosis of dementia of Alzheimer's type based on DSM-IV. We scored the Mini Mental State Examination(MMSE), Global Deterioration Scale(GDS), Clinical Dementia Rating(CDR), and the Korean Neuropsychiatric Inventory(K-NPI). We also measured levels of homocysteine, folate, and vitamin $B_{12}$ in the plasma. Results : We found statistically significant positive correlations between homocysteine concentration with NPI total score, and with scores of several sub-domains such as delusion, agitation/aggression, depression/dysphoria, and elation/euphoria. No significant correlation existed between homocysteine levels and scores of MMSE, GDS, and CDR. Conclusions : This study shows that plasma homocysteine levels are associated with BPSD. Further research is necessary to identify pathophysiologic mechanisms underlying these relationships.
토지이용변화에 따른 미계측 유역의 기저유출량 산정 및 평가
이지민,신용철,박윤식,금동혁,임경재,이승오,김형수,정영훈 한국습지학회 2014 한국습지학회지 Vol.16 No.4
기후변화와 도시화는 기저유출이 하천유량에 미치는 계절별 특성에 변동성을 초래한다. 이러한 기저유출의 변동성은 수생태의 혼란을 유발할 뿐만 아니라 불안정한 수자원 관리를 초래할 수 있다. 토지이용변화는 직접유출과 기저유출에 영향을 주며, 결과적으로 다른 수문순환 요소들에게 미치게 된다. 일반적으로 기저유출은 관측된 하천유량을 통해 산정되지만, 모델링의 유량 예측을 통해서 미계측 유역의 기저유출량 산정에 유용하게 사용 될 수 있다. 따라서, 본 연구의 목적은 1) RECESS 통해 alpha factor를 산정한 후, SWAT 모형에 적용하여 보정 예측을 향상시키고, WHAT 시스템을 미계측유역의 적용하여 기저유출을 분석하며, 3) 토지이용변화에 따른 기저유출 특성을 평가하는 것이다. 이러한 목적으로 미계측 지역인 갑천 유역에 Period 1(1990-1996)과 Period 2(2000-2006)로 설정하여 적용하였다. RECESS를 통해 alpha factor를산정한 후, SWAT 모형 보정에 적용한 결과는 유량예측의 정확성을 향상시키고, 기저유출의 특성인 감수부분도 반영되었다. 두기간 사이의 연평균 기저유출을 비교했을 때 토지이용변화는 연평균 기저유출량에 큰 영향을 미치지 않는 것으로나타났다. 그러나 두기간 사이의 계절별 기저유출의 분포를 비교했을 때 토지이용변화는 기저유출의 계절별 특성에서 큰상이성을 초래했다. 따라서 토지이용변화로 인한 갑천 유역의 유량 및 기저유출의 변동성은 금강 본류로 전달되기 때문에 계절별 변화에 따라 전략적으로 분석 및 관리가 필요하다. Baseflow gives a significant contribution to stream function in the regions where climatic characteristics are seasonallydistinct. In this regard, variable baseflow can make it difficult to maintain a stable water supply, as well as causingdisruption to the stream ecosystem. Changes in land use can affect both the direct flow and baseflow of a stream, andconsequently, most other components of the hydrologic cycle. Baseflow estimation depends on the observed streamflow ingauge watersheds, but accurate predictions of streamflow through modeling can be useful in determining baseflow data forungauged watersheds. Accordingly, the objectives of this study are to 1) improve predictions of SWAT by applying thealpha factor estimated using RECESS for calibration; 2) estimate baseflow in an ungauged watershed using the WHATsystem; and 3) evaluate the effects of changes in land use on baseflow characteristics. These objectives were implementedin the Gapcheon watershed, as an ungauged watershed in South Korea. The results show that the alpha factor estimatedusing RECESS in SWAT calibration improves the prediction for streamflow, and, in particular, recessions in the baseflow. Also, the changes in land use in the Gapcheon watershed leads to no significant difference in annual baseflow betweencomparable periods, regardless of precipitation, but does lead to differences in the seasonal characteristics observed for thetemporal distribution of baseflow. Therefore, the Guem River, into which the stream from the Gapcheon watershed flows,requires strategic seasonal variability predictions of baseflow due to changes in land use within the region.
치성각화성낭종 (Odontogenic Keratocyst)환자의 치험례
이지민,박재홍,김광철,최성철 大韓小兒齒科學會 2008 대한소아치과학회지 Vol.35 No.4
치성각화성낭종(Odontogenic keratocyst. OKC)은 치체(dental lamina)로부터 발생하는데,모든 악골 낭의 5~17% 정도를 차지하며 낭의 내부는 이장상피로부터 유래한 점액성이나 치즈양 물질인 케라틴(keratin)으로 채워져 있다. 치성낭 중 가장 높은 재발률을 보인다는 것이 이 낭의 중요한 특정이다. 간혹 기저층에서 인접 결체조직 벽으로 돌기가 증식하기도 하며 결체조직 벽 내에 존재하는 치성 상피조직 섬의 증식이 위성 소낭을 발생시키기도 한다. 이들 소낭들이 치성각화성낭종의 높은 재발률의 원인으로 여겨진다. 치성각화성낭종은 다양한 연령층에서 발견되나, 20대와 30대에서 호발한다. 남성에서 다소 호발하며 하악,특히 제3대구치와 하악지 부위에서 자주 발생한다. 대개 피질골의 팽융에 의해 처음 발견되며 매복치와 관련되어 있고 일반적으로는 증상이 없지만 동통과 감염이 나타날 수도 있다. 흡인시 걸쭉한 노란 치즈양 물질인 케라틴이 관찰되며 특히 재발이 잘 된다. 치성 각화낭의 중요한 특징 중의 하나는 병소가 피질골의 팽창을 많이 유발시키지 않으면서 악골의 내면을 따라 성장한다는 것이다. 치성각화성낭종화낭은 인접 치아를 변위시키고 흡수사킬 수 있으나 함치성낭보다는 정도가 심하지 않다. 하악관을 하방으로 변위시키기도 하며 상악 병소의 경우는 상악동을 침범해서 상악동 전체를 차지하기도 한다. 본 증례는 7세 10개월 된 여아의 하악 우측 제2유구치 부위에 발생한 치성각화성낭종에 대한 증례로써 전신마취하 낭종적출술을 시행하였다. 낭종에 포함된 제1.2유구치,유견치 및 제1소구치 치배를 발거하였으며,현재 공간유지장치를 장착후 주기적으로 내원중이다. Odontogenic keratocyst is classified as a developmental odontogenic cyst and is believed to arise from cell rests of the dental lamina. It accounts for 3% to 11% of all jaw cysts and they occur twice as often in the mandible as in the maxilla. Histologically, the cysts are lined by stratified, keratinizing, squamous epithelium. Daugther cysts or microcysts are often observed microscopically. The recurrence rate has been reported variously, but is known by its high recurrence rate. These lesions are more common in males than in females, occur over a wide age range and are typically diagnosed during the 2nd and 3rd decade. The diagnosis depends on the cyst's microscopic features and is independent of its location and radiographic appearances. This cyst is a radiolucent lesion that is often multiloculated, has a smooth or scalloped border. The cyst is characteristically located in the body and ramus of the mandible, and often occurs in conjunction with an impacted tooth. This case report describes an odontogenic keratocyst on the lower right molar area of an 8-year-old girl. The cyst was removed under the general anaesthesia, and is being checked regularly for any recurrences.
이지민,최영철,김광철,최성철 大韓小兒齒科學會 2009 대한소아치과학회지 Vol.36 No.2
치외치(Dens Evaginatus)란 교합면에 법랑질이 원추형으로 돌출되어 결절을 형성한 치아로 치아발육중 법랑기의 내측법랑상피가 외부로 과증식되거나 치수 간엽조직이 국소적으로 과증식되어 나타난다. 결절은 교합력이나 저작에 의해 파절 또는 마모되기 쉬우며 따라서 이로 인하여 치수노출에 의한 감염이 야기될 수 있다. 치외치는 예방목적으로 결절을 주기적으로 조금씩 갈아주어 2차 상아질을 유도하거나 전색제등으로 결절주위를 보강하여 자연마모를 유도할 수 있다. 반면 이미 증상을 보인 치아에 대해서는 근관치료를 시행하거나, 미완성치근인 경우 치근단유도술(Apexogenesis)이나 치근단형성술(Apexification)을 시행한다. 치근단유도술이란 생활력을 가진 미성숙 영구치의 손상, 또는 치아우식에 의한 치수노출 시 치수절단술을 시행하여 치수의 생활력을 유지시켜 정상적인 치근으로 발육하도록 유도하는 술식을 말한다. 주로 수산화칼슘을 이용한 통상의 치수절단술이 이용되고 이후 계속적인 치근형성 확인을 위해 주기적 방사선검사가 요구된다. 본 증례는 하악 좌측 제2소구치 부위의 동통을 주소로 내원한 환자에 대한 것으로, 임상검사결과 양측 소구치 부위에 치외치를 확인하게 되었다. 이에 수산화칼슘을 통한 치근단유도술을 시도하였고, 3년간 주기적 내원을 통해 치료한 결과 치근의 근심면의 비정형적 발달을 보였다. 현재 이 치아는 임상증상과 방사선 사진을 통해 확인한 결과 특이한 염증소견 없는 예후를 보이고 있기에 보고하는 바이다. Dens evaginatus is a dental anomaly most commonly seen in premolar teeth in which a tubercle or protuberance projects from either the center of the occlusal surface or the buccal triangular ridge. These tubercles are easily fractured from mastication as the tooth erupts and frequently leads to pulp necrosis as a common complication. To prevent these sequelae, prophylactic treatment soon after the tooth starts erupting is essential. These preventive treatments include, selective grinding and protection of the tubercle by pit and fissure sealant. When the tooth does shows signs of pulp necrosis and apical periodontitis, endodontic procedures are needed. Apexification and apexogenesis are usually the treatment of choice for the affected teeth which have immature apices. Apexogenesis is a vital pulp therapy procedure performed to encourage continued physiological development and formation of the root end. It involves removal of the inflamed pulp and the placement of calcium hydroxide on the remaining healthy pulp tissue. This case report describes an atypical apexogenesis of a mandibular premolar which showed to be a dens evaginatus. The tooth which was treated with calcium hydroxide shows good results and is planned for permanent root canal filling.