• 대한환경공학회지
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• 제27권7호
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• pp.712-718
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• 2005

생물처리에 생분해 지표로 이용되는 Glucose를 주 탄소원으로 하고 난분해물질로 알려져 있는 아조계 염료를 부탄소원으로 하여 이들의 저감패턴을 백색 부후균인 T. versicolor와 P. chrysosporium을 통해 관찰하였으며, 그 결과 두 기질(dual substrate)의 저감 패턴을 정형화된 단계별로 관찰할 수 있었다(새로운 환경 적응기, 주탄소원 소모기, 합성 효소에 의한 부탄소원 소모기). 또한 두 균주의 겉보기 최종 Orange II, 색도, COD 제거량을 비교한 결과 최대 5%범위 내에서 유사한 결과를 보여주었으나, 이러한 결과가 반드시 Orange II 분해 과정의 동일성을 의미하는 것은 아니었다. 즉, T. versicolor와 P. chrysosporium의 효소 발현 특성을 분석한 결과, 선행 연구 결과와 함께 다단계로 진행되는 Orange II 분해 과정(Pathway)을 고려할 때, 겉보기 Orange II 저감과 직접적으로 연계된 참여 효소로서 T. versicolor가 Lac를 이용하였고, P. chrysosporium은 LiP를 이용하는 것으로 판단되며, 그에 따라 발현 효소 차이로 인한 분해 과정 및 중간물질 생성이 상이할 것으로 예상된다.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1181-1186
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• 2003

Chemical Mechanical Polishing (CMP) is an essential dielectric planarization in multilayer microelectronic device fabrication. In the CMP process, it is necessary to minimize the extent of surface defect formation while maintaining good planarity and optimal material removal rates. The polishing mechanism of W-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. Thus, it is important to understand the effect of oxidizer on W passivation layer, in order to obtain higher removal rate (RR) and very low non-uniformity (NU %) during W-CMP process. In this paper, we compared the effects of oxidizer or W-CMP process with three different kind of oxidizers with 5 wt% hydrogen peroxide such as Fe(NO$_3$)$_3$, H$_2$O$_2$, and KIO$_3$. The difference in removal rate and roughness of W in stable and unstable slurries are believed to caused by modification in the mechanical behavior of Al$_2$O$_3$ particles in presence of surfactant stabilizing the slurry.

• Journal of Korean Neurosurgical Society
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• 제30권7호
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• pp.876-882
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• 2001

Objectives : Meningeal hemangiopericytoma is a rare tumor. Clinical and radiological features are similar to those of an ordinary meningioma. But its biological behavior is quite different from those of a meningioma as it brings profuse bleeding in the operation field, frequent recurrence and metastasis to other systemic organs even in the case of gross total resection. In order to find out the prognostic factors and to compare longterm outcome after various treatment modalities, the authors reviewed consecutive 20 operated cases of meningeal hemangiopericytoma to characterize their clinical features, surgical outcomes and effectiveness of the radiation therapy. Methods : Twenty patients with a hemangiopericytoma were treated between 1982 and 1999 in our department. They are composed of 13 patients of hemangiopericytoma and 7 patients who were initially diagnosed as angioblastic type meningioma and then confirmed as a hemangiopericytoma after review of their previous histopathology slides. The mean follow-up period was 99 months(1-256 months). The long-term outcomes after various treatment modalities were evaluated according to recurrence-free survival and image follow-up. Recurrence-free survival curves are compared between the patient groups according to the extent of removal and radiation therapy. Results : There were 10 cases of recurrence and 4 cases of distant metastases ; lung, liver and femur(2 cases) respectively. The 5-year recurrence rate was 37%, while the 10-year recurrence rose to 77%. There was also statistically significant difference of median recurrence-free survival between the completely-resected group(Simpson grade 1 or 2) and partially-resected group(Simpson grade 3 or 4 or 5) ; 137 months compared to 47 months, respectively(p=0.009). The median recurrence-free period after subtotal resection of tumor and postoperative radiotherapy was 47 months compared to 117 months of the patients who underwent gross total resection of tumor and did not receive radiotherapy. But radiation therapy alone did not show significant difference in recurrence-free survival. Marked tumor volume reduction and easy removal of tumors without bleeding were found in 2 recurred cases. Conclusion : The extent of tumor resection and presence of metastasis are the most important factors related to long-term outcome of the patients with hemangiopericytoma. Radiation therapy after the first operation did not have a role in extending the recurrence-free survival, but it affected favorably to decrease the size of residual mass and intraoperative bleeding during the second operation.

• Journal of Korean Neurosurgical Society
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• 제63권6호
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• pp.821-826
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• 2020

Objective : Hyperostosis in meningiomas can be present in 4.5% to 44% of cases. Radical resection should include aggressive removal of invaded bone. It is not clear however to what extent bone removal should be carried to achieve pathologically free margins, especially that in many cases, there is a T2 hyperintense signal that extends beyond the hyperostotic bone. In this study we try to investigate the perimeter of tumour cells outside the visible nidus of hyperostotic bone and to what extent they are present outside this nidus. This would serve as an initial step for setting guidelines on dealing with hyperostosis in meningioma surgery. Methods : This is a prospective case series that included 14 patients with convexity meningiomas and hyperostosis during the period from March 2017 to August 2018 in two university hospitals. Patients demographics, clinical, imaging characteristics, intraoperative and postoperative data were collected and analysed. In all cases, all visible abnormal bone was excised bearing in mind to also include the hyperintense diploe in magnetic resonance imaging (MRI) T2 weighted images after careful preoperative assessment. To examine bony tumour invasion, five marked bone biopsies were taken from the craniotomy flap for histopathological examinations. These include one from the centre of hyperostotic nidus and the other four from the corners at a 2-cm distance from the margin of the nidus. Results : Our study included five males (35.7%) and nine females (64.3%) with a mean age of 43.75 years (33-55). Tumor site was parietal in seven cases (50%), fronto-parietal in three cases (21.4%), parieto-occipital in two cases (14.2%), frontal region in one case and bicoronal (midline) in one case. Tumour pathology revealed a World Health Organization (WHO) grade I in seven cases (50%), atypical meningioma (WHO II) in five cases (35.7%) and anaplastic meningioma (WHO III) in two cases (14.2%). In all grade I and II meningiomas, bone biopsies harvested from the nidus revealed infiltration with tumour cells while all other bone biopsies from the four corners (2 cm from nidus) were free. In cases of anaplastic meningiomas, all five biopsies were positive for tumour cells. Conclusion : Removal of the gross epicentre of hyperostotic bone with the surrounding 2 cm is adequate to ensure radical excision and free bone margins in grade I and II meningiomas. Hyperintense signal change in MRI T2 weighted images, even beyond visible hypersototic areas, doesn't necessarily represent tumour invasion.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.77-86
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• 2020

Persulfate-based advanced oxidation processes (AOPs) can oxidize various organic pollutants. In this study, persulfate/Fe(II) system was utilized in phenol removal, and the effect of various organic and inorganic chelators on Fe(II)-medicated persulfate activation was investigated. The feasibility of persulfate/Fe(II)/chelator in cleanup of phenol-contaminated sediment was confirmed through toxicity assessment. In persulfate/Fe(II) conditions, the rate and extent of phenol removal increased in proportion to persulfate concentration. In chelator injection condition, the rate of phenol removal was inversely proportional to chelator concentration when it was injected above optimum ratio. Thiosulfate showed greater chelation tendency with persulfate than citrate and interfered with persulfate access to Fe(II), making the latter a more suitable chelator for enhancing persulfate activation. In contaminated clay sediment condition, 100% phenol removal was obtained within an hour without chelator, with the removal rate increased up to four times as compared to the rate with chelator addition. A clay sediment toxicity assessment at persulfate:Fe(II):phenol 20:10:1 ratio indicated 71.3% toxicity reduction with 100% phenol removal efficiency. Therefore, persulfate/Fe(II) system demonstrated its potential utility in toxicity reduction and cleanup of organic contaminants in sediments.

• 대한치과의사협회지
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• 제56권8호
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• pp.418-422
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• 2018

Subcutaneous emphysema is relatively rare postoperative complication in the oral and maxillofacial region. Most cases reported in maxillofacial area relate to the use of high-speed handpiece. However, in this case, subcutaneous emphysema was caused by compressed air blow performed during suture removal. Cone-Beam Computed Tomography was conducted to evaluate the extent of diffusion bubbles.. In this report, we describe etiology, diagnosis, prevention and management of subcutaneous emphysema in the maxillofacial area.

• 한국환경과학회지
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• 제13권12호
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• pp.1059-1065
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• 2004

Bio sparging experiments were conducted in a laboratory column to investigate the potential removal of diesel contaminated groundwater. The objectives in this study were (a) to determine the extent of diesel degradation in laboratory columns under supplement of nutrient; (b) to determine the effect of variation of air flow in the removal of diesel and (c) to evaluate the potential enhancement of diesel degradation as a function of temperature. Our results showed that the nutrient supplement and higher air flow greatly enhanced diesel degradation. However, the variation of water temperature examined slightly increased degradation rate of diesel fuel.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 추계학술발표회
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• pp.7-11
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• 1999

Soil washing process being operated in ex-situ mode using surfactants could be appropriate one of the most effective one for remediation. The choice of surfactants has been considered most significantly to accomplish tile reduction of expenditure and the increase of efficiency. This study was carried out screening test and solubility, washing experiment, and surfactant sorption experiments for 18 kinds of surfactant obtained. Results from each surfactant's PSR obtained by the slope indicated that nonionic surfactants have much higher solubility for HOCs than anion surfactants for that. The washing experiment to find out a removal efficiency of each surfactant's TPH, LE1017 and LE1019 showed high removal efficiency. Through on the result of estimating the extent of adsorption of surfactants for soils, nonion surfactants showed higher adsorption to soils than anion surfactants.

• Membrane and Water Treatment
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• 제3권4호
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• pp.211-219
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• 2012

To enhance the efficiency of water treatment and reduce the extent of membrane fouling, the membrane separation process is frequently preceded by other physico-chemical processes. One of them might be ion exchange. The aim of this work was to compare the efficiency of natural organic matter removal achieved with various anion-exchange resins, and to verify their potential use in water treatment prior to the ultrafiltration process involving a ceramic membrane. The use of ion exchange prior to ceramic membrane ultrafiltration enhanced final water quality. The most effective was MIEX, which removed significant amounts of the VHA, SHA and CHA fractions. Separation of uncharged fractions was poor with all the resins examined. Water pretreatment involving an ion-exchange resin failed to reduce membrane fouling, which was higher than that observed in unpretreated water. This finding is to be attributed to the uncharged NOM fractions and small resin particles that persisted in the water.

• 환경위생공학
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• 제14권4호
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• pp.172-179
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• 1999

In this research, biological treatability test was conduced using seawater flocculated tannery wastewater by fixed biofilm reactor. During one cycle, the removal efficiency of organic corbon obtained with fixed biofilm process for treating tannery wastewater was considerably greater than that with activated sludge process. As the hydraulic retention time increased form 0.5day to 4day, removal efficiency of organic carbon was increased from 72% to 87.3%. Attached biomass in media increased with influent organic loading up to 29g MLSS/L, that could reduce the specific organic loading rate. The continual measurement of attached biomass was possible for the operation of the biofilm reactor. Equal and low nitrication rates were observed in both suspended growth activated sludge process and fixed biofilm process, despite commercial nitrifier was seeded. Through the process of treating the tannery wastewater, EC50 values which is measured by the use of Ceriopdaphnia dubia, were decreased to the extent of 50% after treatment of seawater flocculation and of 83% after biological treatment, respectively, compared to those of the untreated wastewater.