김제시 간척지역 천부 지하수내 철 환원작용 특성에 대한 고찰

김지훈,정태진,류종식,김락현,Kim, Ji-Hoon,Cheong, Tae-Jin,Ryu, Jong-Sik,Kim, Rak-Hyeon 대한자원환경지질학회 2013 자원환경지질 Vol.46 No.1

간척지를 포함하고 있는 연구지역에서 육지에서 해안지역으로 근접할수록 측정된 지하수의 산화환원 전위 (Eh)와 용존 산소량 (DO)은 낮게 관찰되었다 (Eh: 0.57 V ${\rightarrow}$ 0.13 V, DO; 9.7 mg/l ${\rightarrow}$ 1.3 mg/l). 이는 연구지역 지하수의 산화환경이 육지에서 해안가로 근접할수록 호기성 환경에서 아혐기성/혐기성 환경으로 변화한다는 것을 의미한다. 또한 지하수 수질 분석 결과에 의하면 철이온 (Fe)이 지하수에 많이 포함되어 있으며 (> 20 mg/l), 대부분의 2가 철로 존재한다. 이러한 연구지역 해안가 지하수들의 특징들은 지하수들이 철의 환원작용 (Fe reduction)이 일어날 수 있는 혐기성 환경에 위치하고 있음을 지시해준다. 철 환원작용이 일어나기 위해서는 3가 철의 공급원이 필요한데, 관측정 퇴적물의 철이온 추출실험에 의하면 연구지역의 퇴적물은 철 환원작용에 필요한 3가 철이온에 대한 충분한 공급원 역할을 할 수 있다. 따라서 분석한 지하수 및 퇴적물의 결과들을 종합해석하면, 연구지역에서 일어나는 철 환원작용은 갯벌의 간척활동과 많은 관련을 가지고 있는 것으로 추정된다. The study area is located on the western coastal region of Korea, partly had been reclaimed lands. Groundwaters of the coastal area show lower Eh and DO values (Eh: 0.57 V ${\rightarrow}$ 0.13 V, DO; 9.7 mg/l ${\rightarrow}$ 1.3 mg/l), and higher Fe concentrations (> 20 mg/l) than those of the inner land (< 0.3 mg/l), indicating that the redox condition of groundwater changes from oxic into suboxic/anoxic conditions as it flows from the inland toward the coastal area. In addition, Fe speciation of groundwater from the coastal area demonstrates that the most dissolved Fe exist as $Fe^{2+}$, reflecting that groundwater is under the anoxic condition to sufficiently occur Fe reduction. According to the result of Fe extraction with the sediment samples from three wells (A, B, C), the sediments provide enough $Fe^{3+}$ to occur the Fe reduction in the groundwater. Integrated all results of the groundwater and sediment, we infer that the Fe reduction to occur in groundwater is associated with the reclamation processes of the study area.

인접전류패턴을 사용한 변형된 방향 대수적 영상복원법

김지훈,김찬용,김경연,최봉열,Kim, Ji Hoon,Kim, Chan Yong,Kim, Kyung Youn,Choi, Bong Yeol 대한전자공학회 2012 전자공학회논문지 Vol.50 No.8

전기 임피던스 단층촬영법(electrical impedance tomography, EIT)에서 관심 대상물 내부 영상을 복원하는 방법 중 하나인 방향 대수적 영상복원법(directional algebraic reconstruction technique, DART)은 삼각함수형태로 설계된 전류패턴을 외부 전극에 인가하고 이로부터 얻어지는 전압과의 상관관계를 이용하여 영상복원 알고리즘의 입력인 각 전극사이의 저항을 유도하게 된다. 이때, 저항유도 시간이 발생하고 이는 DART 알고리즘을 실시간 영상복원에 적용하는데 장애가 되고 있다. 이 논문에서는 저항유도 시간의 문제를 해결하기 위하여 기존에 사용하던 삼각함수형태의 전류패턴대신 인접전류패턴을 사용한 변형된 방향 대수적 영상복원법(modified directional algebraic reconstruction technique, mDART)을 제안한다. 제안한 방법은 주입한 전류와 측정된 전압으로부터 저항을 유도하지 않고 측정전압을 바로 복원 알고리즘의 입력으로 사용하기 때문에 DART의 영상복원시간의 대부분을 차지하는 저항유도 시간을 없앨 수 있을 뿐만 아니라 인접전류패턴을 사용하여 복원영상의 질도 향상시킬 수 있다. 이 논문의 타당성을 입증하기 위하여 모의실험을 수행하였으며 제안한 방법은 기존 방법보다 복원시간의 개선뿐만 아니라 영상오차 관점에서도 성능이 개선됨을 확인하였다. The directional algebraic reconstruction technique (DART) using the trigonometric current pattern is one of the image reconstruction algorithms in electrical impedance tomography (EIT). This method needs to compute resistances between electrode pairs as using relation between the injected currents and measured voltages for the reconstruction of the inner image. The delay time is incurred in this process. Therefore this paper proposes modified directional algebraic reconstruction technique (mDART) using the adjacent current pattern instead of the trigonometric current pattern to solve the delay time for initial resistance values. The proposed method uses measured voltages instead of computed resistances in the reconstruction algorithm. Hence this method can eliminate the delay time because it does not use the resistances. In conclusion, the proposed method improves image quality and image reconstruction time by using the adjacent current pattern. To prove performance of the proposed method, we carried on computer simulation of various cases.

소아 궤양성 대장염의 수술적 치료 성적

김지훈,김현영,정성은,박귀원,김우기,Kim, Ji-Hoon,Kim, Hyun-Young,Jung, Sung-Eun,Park, Kwi-Won,Kim, Woo-Ki 대한소아외과학회 2005 소아외과 Vol.11 No.2

Ulcerative colitis, an inflammatory bowel disease, is primarily managed medically with a combination of 5-ASA and steroids. However, this chronic disease requires surgical management if symptoms persist or complications develop despite medical management. The clinical course, indications and outcome of surgical management of 21 patients under the age of 15 who were endoscopically diagnosed with ulcerative colitis at the Seoul National University Children's Hospital between January, 1988 and January, 2003 were reviewed. Mean follow up period was 3 years and 10 months. The mean age was 10.3 years old. All patients received medical management after diagnosis and 8 patients (38 %) eventually required surgical management. Of 13 patients who received medical management only, 7 patients (53 %) showed remission, 4 patients are still on medical management, and 2 patients expired due to congenital immune deficiency and hepatic failure as a result of sclerosing cholangitis. In 8 patients who received surgical management, the indications for operation were, 1 patient sigmoid colon perforation and 7 patients intractability despite medical management. The perforated case had a segmental colon resection and the other 7 patients underwent total colectomy with ileal pouch-anal anastomosis. One patient expired postoperatively due to pneumonia and sepsis. and 1 is still on medical management because of mild persistent hematochezia after surgery. Six other operated patients are doing well without medical therapy. Pediatric ulcerative colitis patients can be surgically managed if the patient is intractable to medical management or if complications such as perforation are present. Total colectomy & ileal pouch-anal anastomosis is thought to be the adequate surgical method.

혈액질환에 속발하는 이차성 위암

김지훈,지성배,허훈,진형민,김욱,김동욱,이종욱,민우성,김춘추,전해명,Kim, Ji-Hoon,Jee, Sung-Bae,Huh, Hoon,Chin, Hyung-Min,Kim, Wook,Kim, Dong-Wook,Lee, Jong-Wook,Min, Woo-Sung,Kim, Choon-Choo,Jeon, Hae-Myung 대한위암학회 2007 대한위암학회지 Vol.7 No.4

Purpose: Patients with hematologic diseases such as chronic myeloid leukemia (CML) or chronic lymphoid leukemia (CLL) are known to have an increased chance of acquiring a secondary neoplasm. Stomach cancer is one of the most common malignant diseases in Korea, and we investigated whether the incidence of secondary stomach cancer in patients with a hematologic disease increases, in order to determine if a more intensive screening program for detecting secondary gastric cancer was required. We also investigated the safety of performing a gastrectomy in hematologic disease patients. Materials and Methods: From 1992 to 2006, the medical records of 8376 patients diagnosed with one of the six common hematologic diseases were reviewed. Results: Nine secondary stomach cancers were found among the 8376 patients during the 15-year observation period. No surgical-related complications occurred, and there was no recurrence of stomach cancer if detected early. Conclusion: It seems that a more intensive screening program for detecting secondary gastric cancer in hematologic disease patients is not required, and surgery is not risky in these patients. 목적: 만성 골수성 백혈병이나 말성 림프구성 백혈병에서 이차성 암의 위험은 증가하는 것으로 알려져 있다. 백혈병을 비롯한 혈액질환을 가진 환자에서 우리나라에서 가장 흔한 암 가운데 하나인 위암의 위험이 증가하는지 조사하여 혈액질환 환자를 대상으로 위암에 대한 보다 적극적인 검진이 필요한지 알아보고자 하였다. 또한 응고장애나 면역저하와 같은 수술에 관련된 위험인자가 있을 수 있는 혈액질환 환자에서 위암 수술이 안전하게 이루어질 수 있는지에 대해 조사하고자 하였다. 대상 및 방법: 지난 15년가 성모병원에서 백혈병 및 다발성 골수종, 재생불량성 빈혈로 진단받은 8,376명의 환자를 대상으로 의무기록을 후향적으로 조사하였다. 결과: 총 9예의 이차성 위암이 확인되었다. 감염이나 출혈등 수술관련 합병증은 발생하지 않았으며, 조기에 발견된 경우 재발도 관찰되지 않았다. 결론: 위암의 빈도가 일반인에 비해 크게 증가하지 않아 혈액질환 환자에서 이차성 위암의 감시를 위한 집중적인 프로그램이 따로 도입되어야 할 필요성은 없는 것으로 생각되며, 혈액질환 환자의 위암 수술에 있어 합병증도 크게 증가하지는 않는 것으로 생각된다.

부유형 해양 광생물반응기를 이용한 자외선과 초기 미세조류 접종 농도와의 상관관계 규명

김지훈,박한울,정성균,김수권,김희윤,박용성,홍한마루,이철균,Kim, Z-Hun,Park, Hanwool,Jung, Seong-Gyun,Kim, Su-Kwon,Kim, Hee-Yun,Park, Yong Sung,Hong, Han Ma Roo,Lee, Choul-Gyun 한국해양바이오학회 2015 한국해양바이오학회지 Vol.7 No.2

The purpose of this study was to investigate a relationship between ultraviolet radiation and initial cell density (ICD) of microalgae using a floating marine photobioreactor (PBR). To examine the effect of ultraviolet (UV) radiation in sunlight on biomass productivity as a function of ICD, 0.5-L floating PBRs covered with or without UV cut-off film were placed in an outdoor rectangular tank containing 200 L of water. At the lower ICDs, 0.01 and 0.05 g/L, biomass productivities in the PBRs without UV cut-off film decreased by $278{\pm}21%$ and $222{\pm}3%$ compared with those with the film, respectively. In contrast, the presence of UV cut-off film did not have a significant effect on biomass productivities at the higher ICDs, 0.25 and 1.25 g/L. When the differences in biomass productivity made by the UV cut-off film were plotted against the sum of cell projection area per light receiving area of the PBR, the results revealed that the inhibitory effect of UV on biomass productivity can be negligible when the sum of cell projection area is equal to the light receiving area of the PBR. These results show that photoinhibition caused by UV radiation could be eliminated via operating the PBR with a proper ICD.

대형등명기 모니터링 시스템 설계 및 구현

김지훈,예성현,한순희,Kim, Ji-Hoon,Ye, Seong-Hyeon,Han, Soonhee 한국정보통신학회 2014 한국정보통신학회논문지 Vol.18 No.10

우리나라는 해안선이 복잡하여 연안을 항해하는 선박이나 어선의 안전한 항해 및 조업을 위해 효과적인 항로표지 운영이 필요하다. 특히 대형등명기는 야간에 항상 점등되어 선박의 안전을 보장해야 한다. 등대에 설치된 대형등명기가 점등되지 않을 경우 자신의 선위를 확인할 수 없어 사고가 발생하기 쉬우며 이는 커다란 경제적 피해를 야기할 수 있다. 본 연구에서는 대형등명기의 상태정보를 감시 제어하는 대형등명기 모니터링 시스템을 설계하고 구현하였다. 이 시스템은 다양한 장애상황에 신속히 대처하여 해양 안전사고를 미연에 방지할 수 있도록 하는데 그 목적이 있다. Our country has a convoluted coastline and the marine weather fluctuates locally, so it needs effective AtoN operation for the safe navigation of vessels and fishing boats sailing the coast. Especially, large beacon must ensure the safety of the vessels and always lit at night. If large beacons installed in the lighthouse are not lit, vessels can not assure their location. Thus the accidents is likely to occur, which can cause great economic damage. In this paper, we developed a monitoring system of large beacon to monitor and control the status of information. This system was designed for a special purpose of taking precautions against possible accidents on the sea.

Coded Layered Space-Time Transmission with Signal Space Diversity in OFDM Systems

김지훈,이인규,Kim, Ji-Hoon,Lee, In-Kyu The Korean Institute of Communications and Informa 2007 韓國通信學會論文誌 Vol.32 No.7c

V-BLAST (Vertical Bell Labs Layered Space-Time) 시스템은 다중 안테나를 사용하는 시스템에서 각각의 레이어를 간섭 무효화 및 제거기법을 통하여 추정하기 때문에 간단한 복잡도에 비해 높은 전송률을 가능하게 한다. 본 논문에서는 신호 공간 다이버시티 기법을 적용시킨 V-BLAST 시스템을 제안하고자 한다. 신호 공간 다이버시티 기법의 큰 장점은 신호좌표를 회전시키고 인페이즈 (inphase) 와 쿼드러쳐 (quadrature) 성분을 섞어줌으로서 추가적인 대역폭이나 전송 파워의 상승 없이도 다이버시티 이득을 얻을 수 있다. 모의실험을 통해서, 본 논문에서 제안하는 시스템의 성능이 이상적인 시스템 성능에 비해 0.5dB로 근접함을 보여주고자 한다. In multiple antenna systems, vertical Bell Labs Layered Space-Time (V-BLAST) systems enable very high throughput by nulling and cancelling at each layer detection. In this paper, we propose a V-BLAST system which combines with signal space diversity technique. The benefit of the signal space diversity is that we can obtain an additional gain without extra bandwidth and power expansion by applying inphase/quadrature interleaving and the constellation rotation. Through simulation results, it is shown that the performance of the proposed system is less than 0.5dB away from the ideal upper bound.

특발성 망막앞막에서 망막앞막 제거 시에 발생하는 망막점상출혈과 내경계막 손상

김지훈,박현준,이지은,엄부섭.Ji Hun Kim. MD. Hyun Jun Park. MD. Ji Eun Lee. MD. PhD.. Boo Sup Oum. MD. PhD. 대한안과학회 2012 대한안과학회지 Vol.53 No.6

Purpose: To evaluate the relationship between retinal dot hemorrhage that occurred during membrane peeling (MP) and the damage to the internal limiting membrane (ILM) at idiopathic epiretinal membrane (ERM). Methods: The authors of the present study retrospectively reviewed 50 eyes of 50 consecutive patients who underwent vitrectomy with MP for idiopathic ERM. For all the patients, the ILM was stained with indocyanine green following MP. ILM damage was evaluated using microscopy during the operation. Tissue was examined by light and electron microscopy. Whether or not retinal hemorrhage occurred during the MP and the location of the hemorrhage were also investigated. Results: During the MP for idiopathic ERM, ILM damage was observed in 43 (86%) of 50 eyes, and some defects of the ILM due to simultaneous removal with the ERM were observed in 37 (74%) of 50 eyes. Retinal dot hemorrhage occurred during the MP in 32 eyes (64%) and did not occur in 18 eyes (36%). In 32 eyes with retinal hemorrhage, ILM damage was observed in 30 eyes (94%). Large or small defects of the ILM due to simultaneous removal with the ERM were observed in 27 of 30 eyes, and ILM tear was observed in 3 eyes. The hemorrhage occurred in 2 eyes without gross ILM damage during the MP. Among 18 eyes without retinal hemorrhage, large or small defects of the ILM due to simultaneous removal with the ERM were observed in 10 eyes (56%). ILM tear was observed in 2 eyes, ILM detachment was observed in 1 eye, while ILM remained intact in 5 eyes (28%). The number of eyes where both ERM and ILM were peeled simultaneously was significantly higher in the cases with retinal hemorrhage (p = 0.047). Cases of hemorrhage in Gass grade 2 were statistically higher than that in Gass grade 1 (p = 0.015). OCT type of ERM did not have significant correlation with retinal hemorrhage or ILM damage during the MP. Conclusions: During the MP for idiopathic ERM, ILM damage was observed in 86% of patients, and some defects of the ILM due to simultaneous removal with ERM were observed in 74% of patients. It is highly suggestive that ILM is damaged at the hemorrhage site if retinal dot hemorrhage occurred during the MP for idiopathic ERM. J Korean Ophthalmol Soc 2012;53(6):786-791

소족지 변형에서 시행한 관절 절제 성형술

김지훈,박형준,서진수,Kim, Ji Hoon,Park, Hyung Jun,Suh, Jin Soo 대한족부족관절학회 2014 대한족부족관절학회지 Vol.18 No.4

Purpose: The objective of this study was to examine the clinical results and effectiveness of resection arthroplasty for correction of lesser toe deformity. Materials and Methods: From January 2000 to November 2012, 92 cases of resection arthroplasty for lesser toe deformity were reviewed. Hammer toe was the most common type of deformity, accounting for 44 toes (33 patients). Hallux valgus was the most common comorbid illness. Second toe was the most commonly affected toe and proximal interphalangeal joint was the most common location of resection arthroplasty (69 toes, 75.0%). We also analyzed the alignment of phalanges using the last follow-up weight bearing radiographic image. The analysis included clinical evaluation with American Orthopaedic Foot and Ankle Society (AOFAS) score as well as subjective satisfaction. Results: Flexor tenotomy (19 cases) was the most common combined surgery. Floating toe (4 cases) was the most common complication. The last follow-up alignment of phalanges was better than good in 71 toes (77.2%) in anteroposterior view and in 69 toes (75.0%) in lateral view. Sixty one cases (85.9%) resulted in better satisfaction than 'good' and the final average AOFAS score was 87.4. Conclusion: Resection arthroplasty is a valuable surgical option for treatment of lesser toe deformity, with high patient satisfaction, easy surgical technique and remarkable correction of deformity.

PTFE함량에 따른 아연공기전지의 Cathode 특성연구

김지훈,엄승욱,문성인,윤문수,김주용,육경창,박정후,Kim, Jee-Hoon,Eom, Seung-Wook,Moon, Seong-In,Yun, Mun-Soo,Kim, Ju-Yong,Yug, Gyeong-Chang,Park, Jeong-Hoo 한국전기화학회 2003 한국전기화학회지 Vol.6 No.3

아연공기전지는 공기중의 산소를 사용하므로 cathode의 재활용이 가능하다는 장점이 있으며 아연의 이론용량이 820(mAh/g)로 상당히 높다 또한 아연공기전지는 저율방전에서 방전말기까지 아주 평탄한 방전전압을 유지한다. 그러나, 고율방전에서는 방전전압이 낮아지고 에너지가 감소하며 cathode에 포함되어 있는 PTF도의 함량에 따라 저항 및 기공율에 많은 변화를 보이고 있다. 이에 본 연구에서는 전지의 에너지, 방전용량, 방전전압, DC저항, GSM, ASTM에 의한 기공율 측정을 통해 cathode내의 PTFE함량이 아연공기전지에 미치는 영향을 연구하였다. 그 결과 결합제의 함량이 감소할수록 전지의 특성이 향상되었으며 $15wt\%$일 때 가장 우수한 전지특성을 얻을 수 있었다. Zinc Air batteries obtain their energy density by utilizing ambient oxygen as the cathode materials. And specific capacity of zinc powder is as high as 820 mAh/g. When Zinc Air battery discharged at low current, then discharge voltage profile has very flat pattern until reach to end of voltage. But, when Zinc Air battery discharged at high current, then discharge voltage and energy becomes very low. So we focused on resistance and porosity of cathode with contents of PTFE. Wf studied on the effects of PTFE on performance of Zinc Air batteries. So we have got optimum contents of PTFE binder.