전기전도도 측정을 통한 반류수 MLE공정에서 공기공급 제어기술 개발

장신요(Shinyo Chang),신풍식(Pung Shik Shin),정연구(Yeon-Koo Jeong),최영준(Young June Choi) 대한환경공학회 2020 대한환경공학회지 Vol.42 No.3

목적 : 반류수를 대상으로 무산소조에서 전기전도도 측정을 통해 호기조의 공기공급량을 제어할 수 있는 기술을 개발하여 공정성능 향상 및 에너지 사용량 절감을 달성하고자 하였다. 방법 : 전기전도도가 생물학적처리의 운전지표로 활용될 수 있는지를 검증하기 위해 각 공정별 수질인자와 전기전도도의 상관성 분석을 여름철(메탄올 투입), 겨울철, 가을철 시기로 나누어 실험하였다. 기존에 제시된 필요공기량 수식을 간단히 정리하여 경험식을 제시하고, 이를 활용해 전기전도도 범위에 공기공급량을 순차적으로 넣어 조견표를 작성하였다. 성능평가는 암모니아성질소와 총무기질소의 제거효율, SNR과 SDNR, 공기공급량의 변화, 유입수 변화에 대한 공정의 안정성 등을 기준으로 판단하였다. 결과 및 토의 : 계절별로 전기전도도와 각 수질항목의 상관계수가 0.5267 ~ 0.9115 범위로 암모니아성질소, 총무기질소, DOC, 인산염인 순서로 높게 산출되었다. 상관계수 0.5 이상으로 생물학적 처리공정의 운전지표로 전기전도도 가 활용될 수 있음을 알 수 있었다. 전기전도도와 암모니아성질소의 회귀식은 계절별로 재현성이 확보되어 전기전도도를 통해 암모니아성질소를 추정하는 것이 가능할 것으로 판단된다. 호기조 말단 DO가 3.4 mg/L 정도에서 겨울철 질소처리효율이 가장 양호하였다. 호기조 DO는 공기공급량으로 제어할 수 있으며 질소와 상관성이 높은 전기전도도를 직접 측정하여 공기공급량을 제어하고 질소처리효율을 향상시키는 것이 가능함을 알 수 있었다. 전기전도도와 유입유량을 통해 필요공기량을 산정할 수 있는 경험식을 제시하였고, 식 계수를 구한 결과 A", (B" + X") 는 각각 0.0589 (m³-air/h)/(m³/h)/(μS/cm), -77.562 (m³-air/h)/(m³/h)로 나타낼 수 있었다. 겨울철기간 무산소조의 전기전도도 측정값에 따라서 공기공급량을 자동 제어한 결과는 총무기질소 제거효율과 SDNR이 실플랜트 조건보다 각각 8.3%, 0.007 g-N/g-MLSS/d 높게 나타났다. 자동제어한 기간 동안에 공기공급량/유입유량 평균비가 36(m³-air/h)/(m³/h)로 실플랜트 조건보다 공기공급량을 21.7% 감소시킬 수 있었다. 결론 : 전기전도도 기반 MLE공정의 공기공급 제어기술은 질소제거 효율 향상 및 에너지 사용량 절감을 동시에 달성할 수 있을 것으로 판단된다. Objectives : This study aimed to achieve improved process performance and energy saving by developing a technology to control the air supply of an aerobic basin by measuring the conductivity in the anoxic basin. Methods : To verify whether conductivity can be used as an operation indicator of biological treatment, the correlation analysis between water quality factor and conductivity of each process was conducted by dividing into summer (methanol input), winter and autumn periods. An empirical formula was presented by briefly arranging the required air quantity formula, and a quick reference was prepared by putting air supply in the conductivity range sequentially. The performance evaluation was judged based on the removal efficiency of ammonia nitrogen and total inorganic nitrogen, SNR and SDNR, the change of air supply, the stability of the process against inflow change. Results and Discussion : The seasonal correlation coefficients of conductivity and water quality items were calculated in the order of ammonia nitrogen, total inorganic nitrogen, DOC, and phosphate in the range of 0.5267 ~ 0.9115. It was found that the conductivity could be used as an operation indicator of the biological treatment process with a correlation coefficient of 0.5 or more. The regression equations for the conductivity and ammonia nitrogen are secured by season, so it is possible to estimate the ammonia nitrogen through the conductivity. At the end of the aerobic basin DO was 3.4 mg/L, the nitrogen treatment efficiency in winter was the best. The aerobic basin DO can be controlled by the air supply, and it can be seen that it is possible to control the air supply and improve the nitrogen treatment efficiency by directly measuring the conductivity having a high correlation with nitrogen. An empirical formula for estimating the required air volume through conductivity and inflow is presented. A" and (B" + X") are 0.0589 (m³-air/h)/(m³/h)/(μS/cm) and -77.562 (m³-air/h)/(m³/h). The result of automatic control of air supply according to the measured conductivity of anoxic tank during winter season showed that total inorganic nitrogen removal efficiency and SDNR were 8.3% and 0.007 g-N/g-MLSS/d higher than the actual plant conditions, respectively. During the automatic control period, the air supply/inflow average ratio was 36 (m³-air/h)/(m³/h), which could reduce the air supply by 21.7% compared to the actual plant conditions. Conclusions : The air supply can be estimated from the flow rate and conductivity. The air supply control technology of the conductivity-based MLE process will be able to simultaneously improve nitrogen removal efficiency and reduce energy consumption.

韓國行政指導者의 特性과 役割

崔彰植 동국대학교 행정대학원 1971 행정논집 Vol.2-3 No.-

조혈모세포이식 환자에서 침습성 진균 감염에 대한 이트라코나졸 액과 플루코나졸 시럽의 예방 효과 : 전향적, 무작위, 비교 임상시험

최수미,이동건,최정현,박선희,엄기성,김유진,김희제,민창기,유진홍,김동욱,이종욱,민우성,신완식,김춘추 대한감염학회 2005 감염과 화학요법 Vol.37 No.2

목적 : 조혈모세포이식 환자에서 호중구 감소 기간 동안 이트라코나졸 액(ITZS)과 플루코나졸 시럽(FCZS)의 진균 감염에 대한 예방 효과를 전향적으로 비교해 보고자 하였다. 재료 및 방법 : 2001년 8월부터 2002년 6월까지 가톨릭 조혈모세포이식센터에 입원하여 동종 조혈모세포이식을 받은 만 18세 이상의 환자들을 각각 ITZS와 FCZS군으로 무작위 배정하여 침습성 진균 감염 발생과 약제 관련 부작용을 전향적으로 조사하였다. 결과 : ITZS군에 40명, FCZS군에 38명이 배정되었고, FCZS군 환자의 평균 나이가 더 많았다. 시험 약제 평균투여기간은 ITZS군 16.4일, FCZS군 21.9일로 ITZS군이 더 짧았다. 이는 ITZS군에서 소화기 부작용으로 인한 약제 중단이 더 많았기 때문으로 보인다. 시험 약제 투여 후 총 빌리루빈 수치의 유의한 증가가 관찰되었으나, 약제 관련 부작용은 모든 환자에서 가역적이었다. 호중구감소 기간동안 표재성 진균 감염은 두 군에서 모두 발생하지 않았고, 침습성 진균 감염은 ITZS군 5명(12.5%), FCZS군 8명(21.1%)으로 FCZS군에서 많았으나, 통계학적으로 유의하지 않았고, 사망률에도 유의한 차이는 없었다. 결론 : 침습성 진균 감염에 대한 이트라코나졸 액과플루코라졸 시럽의 예방 효과에 유의한 차이는 없었으나, 앞으로 더 많은 환자를 대상으로 잘 짝지어진 대조군 연구가 필요할 것으로 보인다. 부작용 중 간독성과 관련하여 이식시 투여되는 여러 약제들과의 상호작용에 대한 연구도 필요할 것이다. Background : Though fluconazole is widely used for antifungal prophylaxis, it is ineffective against mould infections including Aspergillus species. Itraconazole has a broader spectrum than fluconazole but the capsule form shows erratic bioavailability in neutropenic patients. In this study, we compared itraconazole oral solution (ITZS) with fluconazole syrup (FCZS) for the prevention of invasive fungal infection (IFI) in allogeneic hematopoietic stem cell transplant recipients. Materials and Methods : Adults receiving allogeneic hematopoietic stem cell transplantation (HSCT) from september 2001 to June 2002, were randomly allocated to either the ITZS group or the FCZS group. We prospectively evaluated the safety and efficacy of each drug. Results : Out of 78 patients (40 patients in the ITZS group and 38 patients in the FCZS group) who were eligible for this study, 37 patients completed the course of prophylaxis without any evidence of IFI. The mean duration of prophylaxis was 16.4 days for the ITZS group and 21.9 days for the FCZS group (P<0.006). Drug-related adverse events occurred in 28 patients (70.0%) and 19 patients (50.0%) in the ITZS group and the FCZS group, respectively. Common adverse events of ITZS were nausea, vomiting, and diarrhea. Drug-related reversible hepatotoxicity occurred in 4 patients in the ITZS group. There was a significant elevation of total bilirubin level in the ITZS group. The incidence of suspected IFI occurred in 5 patients (12.5%) who received ITZS, compared with 8 (21.1%) who received FCZS (P=0.372). There were no proven IFIs or superficial (oral/vaginal) fungal infections in both groups. Overall mortality was not different between the two groups (2.5% in the ITZS group versus 5.3% in the FCZS group, P=0.610). Conclusion : ITZS and FCZS showed similar protection against IFI during pre-engraftment period. Poor tolerability due to gastrointestinal troubles of ITZS might limit its success as prophylactic therapy. Well matched controlled study with large number of patients will be required in the future.

CdS:In 單結晶의 基本特性과 photosensor로의 應用

강현식,박병채,장성우,이해익,최용대 全北大學校 敎育大學院 1986 敎育論叢 Vol.6 No.-

The opto-electrical properties of the CdS : In single crystals were studied by these means of the scanning electron microscope, X-ray diffraction, optical transmission & photoconductivity, resitivity variation v.s. impurites, and resitivity v.s. photon flux change. By X-ray diffraction measurement, the structure was found to be hexagonal and the lattice constant was calculated to be a_o=4.13Å and c_o=6.75Å The band gap was estimated to be about 2,419eV (300K). By the transmission measure ments a donor impurity level of In or Al was 0.024eV below the conduction level edge. For the application on the photosensor, the resistivity(ρ) variation of the CdS : In was measured with respect to photon flux(P_o) change and to wavelength, the resistivity was found to be ρ=8.75×10^6P_o^-125 (Ω―㎝/Lux) and the photoconductivity showed its highest response peak between 5,000Å and 5,400Å ranges.

지방교육행정기관의 재무분석

김흥식,최창익 충남대학교 부설 회계연구소 2002 회계논집 Vol.3 No.-

본 연구는 지방교육행정기관의 재무분석을 위한 지표를 개발하고 2개 지방교육행정기관의 예산·결산 관련자료를 통해 재무비율 등을 산출하며, 이를 상호 비교하여 해당 교육행정기관의 강·약점을 확인하고 개선할 사항을 제시하는 데 목적이 있다. 이러한 연구를 위해 기존의 관련연구 등을 검토하였으며, 새로운 지표를 개발하여 광역시의 지방교육행정기관 1개 기관(D 교육청)과 도(道) 지방교육행정기관 1개 기관(C 교육청)을 실증적으로 분석하였다. 분석방법은 재무분석을 위해 우선 안정성, 적정성, 발전성으로 구분하여 16개 지표를 개발하고, 지표에 예산·결산 자료를 이용하여 관련 재무비율 등을 산출하였다. 분석결과, C교육청이 7개 지표에서 상대적으로 우수하였으며, D 교육청은 9개 지표에서 상대적으로 우수하였다. 정부예산 중 교육예산이 차지하는 비중은 2002년 기준 20.4%로, 이를 필요한 곳에 적정하고 발전적인 방향으로 사용할 수 있도록 방향을 제시하는 것은 매우 중요하다. 지방교육행정기관의 세입·세출예산을 점검할 수 있는 시스템인 지표의 개발과 아울러 지방교육행정기관에 대한 지속적인 재무분석 노력은 재정의 투명성 제고와 납세자인 국민과 학부모의 알 권리 신장에 기여할 수 있을 것이다. 본 연구는 우리 나라 전체 16개 시·도교육청을 분석대상으로 하지 못한 한계점을 지니고 있다. 그리고 앞으로의 연구에서는 지방교육행정기관의 재무분석을 위한 다양한 재무적·비재무적 지표의 개발과 적용에 관한 실증적 연구가 이루어져야 할 것이다.

Urea 박테리아 전극에 관한 연구

인권식,최창진,김봉원,손무정,김인탁 圓光大學校 基礎自然科學硏究所 1987 基礎科學硏究誌 Vol.6 No.2

Proteus vulgaris 를 ammonia와 carbon dioxide gas-sensor에 고정시켜 감응도와 재현성이 우수한 요소에 대한 박테리아 전극을 직접 제조하여 pH, 온도, 완충용액, 박테리아의 양, 여러 가지 아미노산 및 무기염류에 대한 영향과 전극의 수명 등에 관하여 조사하였다. 먼저 ammonia-박테리아 전극은 25℃에서 pH 7.4인 0.05M phosphate 완충용액을 사용하였을 때가 최적이었으며, 7.0 ×10 exp (-4) -3.0 ×10 exp (-2)M 내에서 직선을 나타내었고, 이때 감응도는 116.7mV/decade였다. 한편, carbon dioxide-박테리아 전극은 30℃, pH7.0, 0.1M phosphate 완충용액에서 가장 우수한 감응을 보였다. 이 경우는 7.0 ×10 exp (-4) - 5.0 ×10 exp (-2)M 내에서 45.4 - 45.7mV/decade를 나타내었다. 이들 두 전극중에서 carbon deoxide-박테리아 전극을 이용하여 요소를 정량한다면 방해물질들의 방해가 최소화되었다. 실제 임상적 응용에서 분광 광도법과 비교한 결과 실험과정이 간단하고 편리하여 신속하게 많은 양의 시료분석이 가능하다. Bio-electrodes for urea have been constructed by immobilizing the Proteus vulgaris on ammonia and carbon dioxide gas-sensors. The bacteria containing urease convert each molecule of urea into two molecules of ammonia and one molecule of carbon dioxide gas. Ammonia-bacterial electrode based on ammonia gas-sensor has linearity in the range of 7.0 ×10 exp (-4) - 3.0 ×10 exp (-2)M urea in pH 7.4, 0.05M phosphate buffer solution at 25℃. While carbon dioxide-bacterial electrode based on carbon dioxide gas-sensor has linearity in the range of 7.0 ×10 exp (-4) - 5,0 ×10 exp (-2)M urea in pH 7.0, 0.1M phosphate buffer solution at 30℃. These electrodes were investigated for the effects of pH, temperature, buffer solutions, bacterial amounts and interferences, and life time. As the clinical applications, urea in urine was determined by these devices and was compared with spectrophotometric method. As the results, those methods were by far more simple and rapid than these method.

형제에서 발견된 단순골낭

안서영,안창현,최갑식 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.3

17-year-old and 14-year-old brothers were referred for evaluation of the cystic lesions on the mandibular anterior area with no symptoms. Neither their mother nor the brothers could recall any past trauma to those areas. Panoramic and intraoral radiographs revealed moderately defined cystic lesions on their mandibular anterior areas. Biopsies on both lesions revealed simple bone cysts. Hereditary cause or familial history of simple bone cysts could not be found in literature review. This case may have been a coincidence. However, further investigation is needed to find the cause of simple bone cysts occurring in patients those are closely related.

단방성 법랑모세포종의 방사선학적 연구

이주덕,안창현,최갑식 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.1

Purpose : To acquire the useful diagnostic information through the analysis of the clinical and radiological characteristics of mandibular unicystic ameloblastoma. Materials and Methods : The researchers compared and analysed the clinical and radiological features of 79 cases of mandibular unicystic ameloblastoma confirmed by histopathlogic examination. Results : The results of our research showed that unicystic ameloblastomas occurred more frequently in males than in females and the incidence is the highest in the 2nd and 3rd decades. These lesions occurred most frequently in angle-ramus area, mandibular molar area, and anterior area in descending order respectively 68.4%, 24%, and 7.6%. These lesions had smooth (54.4%) rather than undulating (45.6%) borders. These lesions showed welldefined borders in 59.5% among all the cases. Root resorption and loss of lamina dura were observed as 55.7% and 58.5% respectively. Displacement of mandibular canal was observed in 55.9% among all the related cases. Internal pattern of lesional radiolucency was observed as even (49.4%) or uneven (50.6%). Conclusion : These results would be helpful in diagnosing of mandibular unicystic ameloblastoma.

구강검진에서 임상검사와 비교한 파노라마방사선사진의 유용성

안서영,안창현,최갑식 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.2

Purpose : To evaluate the efficacy of panoramic radiography by comparing the results of clinical examination with radiographic findings. Materials and Methods : We studied 190 patients (20 men and 170 women; mean age, 40 years; range, 22 to 68 years) who visited the health promotion center of Korea Medical Science Institute and were examined both clinically and by panoramic radiography. We compared results from both examinations. Treatment options by clinical examination were described as “no treatment indicated”, “treatment of dental caries”, “removal of calculus”, “treatment of periodontal disease”, “prothodontic treatment” and “extraction of the third molar”. Findings taken from the panoramic radiography were: dental caries, periapical lesion, alveolar bone loss, calculus deposition, retained root, impaction of the third molar, disease of maxillary sinus, bony change of mandibular condyle, etc. Results : The prevalence of panoramic findings were: 37.9% of dental caries, 17.4% of periapical lesions, 44.7% of alveolar bone losses, 62.6% of calculi deposition, 7.9% of retained roots, 26.8% of third molar impactions, 6.3% of diseases of maxillary sinus, 2.1% of bony changes of mandibular condlye and 35.8% of miscellaneous lesions. Abnormal conditions revealed by panoramic radiography which had not been discovered on clinical examination were: 24.2% of the patients had dental caries, 17.4% had periapical lesions, 7.4% had calculi deposition, 5.3% had retained roots, 15.3% had third molar impactions. The opposite cases were: 5.2% had dental caries, 12.6% had calculi deposition, and 9.5% had third molar impactions. Conclusion : The use of panoramic radiography as a supplement to the clinical examination might be a valuable screening technique.

치성각화낭의 방사선학적 연구

천상득,안창현,최갑식 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.1

Purpose : To acquire the useful diagnostic information through the analysis of the clinical and radiological characteristics of mandibular odontogenic keratocyst. Materials and Methods : The researchers compared and analysed the clinical and radiological features of 112 cases of mandibular odontogenic keratocyst confirmed by histopathlogic examination. Results : Mandibular odontogenic keratocysts occurred more frequently in males than in females and the incidence is the highest in the 2nd and 3rd decades. These cysts occurred in the mandibular posterior area, angle-ramus area and anterior area 51.8%, 31.2% and 17.0% respectively. These cysts had undulating border (69.6%) rather than smooth border (30.4%). Most of these cysts had well-defined hyperostotic border (94.6%). These cysts caused cortical thinning or expansion (78.6%) rather than no cortical reaction (21.4%). Loss of lamina dura was observed in 72.3%, displacement of tooth appeared in 35.7% and root resorption appeared in 12.5% of cases. In 71% of cases, displacement of mandibular canal was observed. Internal patterns of lesional radiolucency were even (61.6%) or uneven (38.4%). Conclusion : These results would be helpful in diagnosing of mandibular odontogenic keratocyst.