교대로 운전되는 두 개의 UV/광촉매반응기로 구성된 폐가스 처리시스템에서의 광촉매의 비활성화 및 재생 특성

이은주 ( Eun Ju Lee ),정찬홍 ( Chan Hong Chung ),임광희 ( Kwang-hee Lim ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.4

본 연구에서는 교대로 운전되는 두 개의 UV/광촉매 반응기로 구성된 폐가스 처리시스템의 운전단계와 단계별 광촉매의 비활성화의 상관관계를 사용된 광촉매에 대한 기기분석을 통하여 규명하였다. 선행연구[Lee와 Lim, Korean Chem. Eng. Research, 59(4), 574-583 (2021)]의 광촉매 반응기 시스템 운전에 사용되지 않은 광촉매를 담지한 다공성 SiO₂ 담체(A4), 1회 운전하는 동안 사용되고 재생을 경험하지 않은 광촉매를 담지한 다공성 SiO₂ 담체(A1), 2회 운전에 사용되고 1회 재생된 광촉매를 담지한 다공성 SiO₂ 담체(A2) 및 3회 운전에 사용되고 2회 재생된 광촉매를 담지한 다공성SiO₂ 담체(A3)와, 1차 재생(AD1) 또는 3차 재생(AD3)된 광촉매를 담지한 다공성 SiO₂ 담체에 대한 BET 분석, SEM, XPS, SEM-EDS 및 FTIR 분석 등을 수행하여, 광촉매를 담지한 다공성 SiO₂ 담체의 비활성화 및 재생 특성을 포함하는 특성 분석을 수행하였다. 그 결과로서, 3회 이상의 여러 번 재생을 수행하는 광촉매의 적정 재생 온도를 200℃ 미만으로 도출하였다. 이러한 광촉매의 적정 재생 온도는 BET 분석결과에서 도출된 기공에 흡착된 에탄올 산화분해 중간생성물의 대부분이 완전 분해가 되어 기공이 재생되는 재생 온도와 거의 일치하였다. 특히, XPS 분석 결과는, 선행 연구[Lee와 Lim, Korean Chem. Eng. Research, 59(4), 574-583 (2021)]에서 광촉매 반응기의 첫 번째 운전 후에 광촉매의 미세한 비활성화가 발생하였음을 나타내었다. 또한, XPS 분석 결과는, 선행연구[Lee와 Lim, Korean Chem. Eng. Research, 59(4), 574-583 (2021)]에서 광촉매 반응기의 두 번째 운전에서 비교적 큰 광촉매의 비활성화가 발생하여 첫번째 운전성능보다 약 5%만큼 못 미치는 에탄올과 황화수소 각각의 제거효율을 초래하였으나, 세 번째 운전에서의 에탄올과 황화수소의 제거효율은 두 번째 운전에서의 에탄올과 황화수소의 제거효율 실험 결과와 거의 비슷하였다는 연구 결과와 일치하였다. 한편, AD3를 사용하여 선행연구[Lee와 Lim, Korean Chem. Eng. Research, 59(4), 574-583 (2021)]에서와 같은 광촉매 반응기의 네 번째 운전을 수행할 것을 가정하면, 두 번째 운전에서보다 더 큰 광촉매의 비가역적 비활성화의 발생으로 인하여 에탄올과 황화수소 제거효율이 가장 크게 저하되리라 예상되었다. In this study, the correlation between operating stages of waste air-treating system composed of two alternatively-operating UV/photocatalytic reactors, and the deactivation of photocatalyst used in each operating stage, was investigated by instrumental analysis thereon. The repeated deactivation and subsequent re-generation of photocatalyst used in the waste air treating system of previous investigation performed by Lee and Lim (Korean Chem. Eng. Research, 59(4), 574-583(2021)), were characterized on virgin photocatalyst-carrying porous SiO₂ media (A4), used photocatalystcarrying porous SiO₂ media (A1, A2 and A3) collected from the corresponding photocatalytic reactor upon 1^st, 2^nd, and 3^rd run, respectively, regenerated photocatalyst-carrying porous SiO₂ media upon 1 time-run (AD1) and 3 times regenerated photocatalyst-carrying porous SiO₂ media upon 3 time-runs (AD3) by instrumental analysis including BET analysis, SEM, XPS, SEM-EDS and FT-IR. As a result, the proper regeneration-temperature for deactivated photocatalyst to be regenerated several times (more than 3 times), was suggested below 200℃. Such temperature of deactivated photocatalystregeneration was almost consistent to the one, according to BET analysis, at which tiny nano-pores blocked by adsorbed ethanol-oxidative and degraded intermediates (AEODI), were regenerated to be reopened through almost complete mineralization of AEODI. In particular, the results of XPS analysis indicated an incurrence of insignificant deactivation of photocatalysis upon 1^st run of UV/photocatalytic reactor (A or C) of the previous investigation. In addition, the results of XPS analysis were consistent with the experimental results of the previous investigation in that 1) deactivation of photocatalyst incurred during 2^nd run of the UV/photocatalytic reactor (A or C) resulted in decreased removal efficiency, by ca. 5% and 5%, of ethanol and hydrogen sulfide, respectively, compared with its 1^st run; 2) there was insignificant difference between the removal efficiencies of its 2^nd run and 3^rd run. Furthermore, the removal efficiencies of ethanol and hydrogen sulfide for hypothetical 4^th run of photocatalytic reactor in the previous investigation, using AD3, were expected to decrease, compared with its 3^rd run, by much more than those for 2^nd run in the previous investigation did, compared with its 1^st run.

PWM을 이용한 트랙터 부착작업기의 자세제어

이성범,이홍주,황성준 안성산업대학교 2002 論文集 Vol.34 No.-

This study was conducted to control the posture of implement attached to tractor, which could make important effects on the working performance and accuracy. A tool bar, should be attached to the 3-point hitch, was designed to control the posture of implement by differentiating distances between one upper link and two lower links independently and simultaneously. By using PWM control method, the hydraulic fluid quantity was controlled proportionally according to the change of duty ratio with a high speed electronic solenoid valve. Computer simulation and fundamental test were also conducted for the developed posture control system using AMESim analysis tool The results of this study could be summarized as follows : 1. According to the results of computer simulation, major design parameters such as PWM control frequency, control agin, orifice diameter, and fluid pressure were determined as 30㎐, 1.5, 1.8㎜, and 10MPa, respectively. Time constant to make 100㎜ of stroke in load direction was about 0.55 seconds. 2. The tool bar, which was consisted of hydraulic cylinders and metal guides, was fabricated and tested for the performance of over all system. 1.6 seconds of response time of the control system was needed at inclination of 22°, and the performance of the posture control system was best at 150MPa of relief pressure, 1.5 of control gain, 20㎐ of PWM control frequency, and 2.2㎜ of orifice diameter, which did not represent considerable difference in compare with the results of computer simulation.

구내신연장치를 이용한 치조골증대술 후 임프란트 매식 : 치험 5예 REPORT OF 5 CASES

이용욱,박충열,송종운,박홍주,김영운,오희균,유선열 대한악안면성형재건외과학회 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.2

Successful alveolar ridge augmentation by distraction osteogenesis method has been reported previously. There are several types of devices for alveolar ridge augmentation. In this paper, a new intraoral distraction device was used on the severe atrophic mandible in order to distract an alveolar ridge vertically in 5 patients. Mean amount of distracted alveolar ridge was 7.4㎜ (5∼9.5㎜). Dental implants were placed in the distracted alveolar bone and good osseointegration was obtained in all patients. Mean follow up period is 2years 6months (7months∼4years 9months). No complications, such as infection or resorption was observed in all patients. Alveolar ridge augmentation by gradual distraction seems to be a safe, simple and reliable procedure.

경남지역의 토양 및 농작물중 게르마늄 함량

이성태,이영한,이홍재,조주식,허종수 한국환경농학회 2005 한국환경농학회지 Vol.24 No.1

양질의 기능성 농산물 생산을 위하여 게르마늄의 농업적 이용에 대한 기초 자료를 제공하고자 경남지역의 토양을 중심으로 지역, 지형, 토양유형 및 토성별 게르마늄 함량과 자연상태에서 재배한 농작물별 게르마늄 함량을 조사하여 그 분포특성을 검토한 결과는 다음과 같다. 토양중 게르마늄 함량을 분석할 결과 성남지역 논 토양 평균 함량은 0.24 mg/kg 이었고, 마산시, 진주시 및 하동군 지역이 0.30 mg/kg 이상으로 높았다. 지형별로는 홍적대지가 0.26 mg/kg으로 약간 높았으나 지형에 따른 큰 차이는 없었다. 토양유형별 게르마늄 함량은 보통답이 0.27 mg/kg으로 사질답과 습답에 비하여 높았으며, 토성별로는 미사질양토가 0.27 mg/kg으로 비교적 높았다. 일반농작물중 게르마늄 함량은 곡류>채소류>과일류 순으로 높았고, 쌀과 보리는 각각 약 68 및 48 μg/kg의 게르마늄을 함유하고 있었으며, 단감과 배는 각각 약 11 및 23 μg/kg으로 전반직으로 낮을 수준이었다. 채소류중 게르마늄 함량은 엽채류>근채류>과채류 순으로 높았으며 특히 상추와 열무중 게르마늄 함량이 각각 약 62 및 65 μg/kg으로서 높았다. 약용작물중 게르마늄 함량을 신선초(Angelica keiskei), 토천궁(Ligusticum chuanxiong), 인삼(Panax ginseng), 삽주(Atractylodes macrocephala), 백지(Angelica dahurica), 맥문동(Liriope platyphylla) 및 도라지(Platycodon grandiflorum)에서 100 μg/kg 이상으로 게르마늄 함량이 높았으며, 선학초(Agrimonia pilose) 및 일당귀(angelica acutiloba)의 함량은 각각 37 및 30 μg/kg으로 낮았다. To investigate the germanium content in paddy soil in Gyeongnam province, 310 paddy soil samples were collected at 19 areas in Gyeongnam, Ulsan and Busan. Contents of germanium in paddy soils were analyzed in different topographies, soil types and soil textures. Average content of germanium in Gyeongnam was 0.24 mg/kg, those of Masan, Jinju and Hadong were above 0.30 mg/kg. Germanium content with different topographies were no difference. Germanium contents in different soil types were 0.27 mg/kg in well adapted soil and 0.23 mg/kg in poorly drained soil. Germanium contents in different soil textures were 0.27 mg/kg in silt loam and 0.23 mg/kg in sandy loam. To determine germanium content on agricultural product in the field, content of germanium in cereals, vegetables and fruits were analyzed. Germanium content of agricultural product was high in the order of cereals>vegetables>fruits. In case of vegetables, germanium contents were high in the order of leaf vegetables>root vegetables>fruit vegetables. Germanium contents were high with 62 and 65 μg/kg in lettuce and young radish, respectively. To analyze the germanium content in medicinal plant, samples were collected from 19 medicinal plants at Hamyang areas. Germanium contents in Angelica keiskei, Ligusticum chuan wng, Panay ginseng and Atractylodes nacrocephala were relatively high with 100 μg/kg above.

타타늄의 열처리 조건에 따른 동전위 양극분극특성 및 표면 미세구조 변화

주동현,이용렬,정영화,양홍서,박상원,이도재,송호준,박영준 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.2

The corrosion resistance of metallic implants is essential for successful implant osseointegration. Moreover, the implant surface should have appropriate surface roughness for the attachment of the osteoblast and collagen fibrils. When titanium is exposed to air a thermodynamically very stable oxide film is formed at once. This oxide is very thin and yet it protects the metal from corrosion instantaneously. However, the oxide would not be ideal, and it would be supposed that the state of oxide film would be various by the different conditions when it is formed. The objective of this study was to evaluate the electrochemical properties and surface microstructural changes of titanium after passivation treatment or exposure to high heat (in vacuum or in air). ASTM grade 2 commercially pure titanium (Ti) disks of 10㎜ diameter were wet ground and polished with 240 and 600 grit SiC, and then ultrasonically cleaned with distilled water and ethanol. Cleansed as-received samples (As-R group) were passivated with 30% nitric acid solution at 50℃ for 15 minutes to make the Pas group. The Std-V samples were made by treating the Ti disks in vacuum quartz tube (10^-8 Torr) at 530℃ for 40 min for stress relieving, followed by annealing at 700℃ for 90 min, and then slow cooling to room temperature. The Std-A samples undergo identical procedure as the Std-V group except that it is done in air. For 530℃-V samples, Ti disks were heated at 530℃ for 40 minutes and slow cooled to room temperature. The 1000℃-V samples were produced by heating Std-V specimens again at 1000℃ for 2 hr, followed by cooling to room temperature. 530℃-A and 1000℃-A samples were also prepared. Potentiodynamic anodic polarization measurement, SEM, AFM and XRD analysis were performed to evaluate the effects of the various treatments. The difference in the mean values of E_corr between groups showed statistically significant difference (P<0.05), but that of I_corr did not show significance (P>0.05). When Ti surface was passivated there was a shift of corrosion potential (E_corr) in the noble direction and a lower corrosion current density (I_corr) value. Std-A samples showed most noble E_corr value among the tested groups. 530℃-V samples showed more noble E-corr than other tested groups except Std-A group. 1000℃-V samples showed more noble E-corr than those of Std-V sample. In the case of Std-, 530℃- and 1000℃-groups, -A sub-groups showed better corrosion resistant characteristics than -V sub-groups in regard to E-corr and I_corr values. In the SEM observations, the surfaces of the As-R samples showed only scratch line on smooth surface. In Pas samples, thick oxide layer covered the surface under high magnification observation. 530℃-A samples were covered by oxide granules, and Std-A samples had 25~50 nm-thick acicular oxides. The 1000℃-A samples were covered by coarse oxide crystals with a granule diameter of 0.1~0.6 μm having a gross appearance of milky white color, which was identified by XRD as a rutile. On the other hand, 1000℃-V samples showed an Widmansta¨tten structrue of which the orientation of the lattice is formed along crystallographic planes of the parent crystals. On the AFM observation, 530℃-A samples showed RMS roughness of 79.38 nm which is 5 times rougher than those of the As-R samples. Std-A sample had a roughness of 330.47 nm which is about 20-times rougher than that of the As-R sample. 1000℃-A samples were covered by coarse granular oxides and the roughness were about 0.56 μm. Vacuum sub-group samples showed a more smooth surface than air sub-group samples, and the oxide film was more dense. Due to variability of the surface treatment and heat treatment conditions, the process of the oxide formation seems to be affected thereby making the corrosion properties and surface micro-morphology different. However, more various electrochemical analysis together with surface analysis, and an investigation for the effects of those on the osteoblast cell adhesion and calcium phosphate apposition are needed for the improvement of the osseointegration rates of the titanium implants.

안성시 지역의 농업기계 보관관리 실태조사

이홍주,이성범,김성엽 안성산업대학교 1999 論文集 Vol.31 No.-

This study was conducted to analyze the storage and management status of major farm machinery, and to present the basic information for the construction of multipurpose storage housing suitable to the individual farmers by identifying current problems. The results of this study are summarized as follows; 1. The average farm area of the surveyed farmers was 4.25㏊, which represents relatively higher than the average of whole country. The mechanization rate for paddy farming was 98% so, the individual storage housing should be concentrated on the farm machinery utilized in paddy farming. 2. The annual operating span of the seasonal farm machinery (such as combine and rice transplanter) showed high difference between farmers and machines. For th rice transplanter, the highest portion of annual operation span was less than 10 days as 70%, and for the combine, that was over 20 days as 36% and the second was 16~20 days as 23%. The average difference in repairing cost for combine between the farmers with and without common storage housing was 100,000won. 3. The percent of storaging farm machinery in the open field for farmers without housing were 44% for power tiller, 16% for farm tractor, 21% rice transplanter, 10% for combine. Each farmer has individual temporary simple housing with various kinds and structure. 4. Most of the farmers, 63.7%, want to use the farm machinery storage housing for multipurpose utilization, 29% only for storaging purpose. Most farmers prefer near the farm house as suitable position of housing, and prefer the area of 132~198㎡ for storage housing. The current problems on common storage housing were insufficient area(44.8%), no problem(29%), improper position, excessive construction cost, inconvenient entrance, etc.

새터민의 기초직업능력 진단

이찬,이용환,이윤조,신재호,홍윤선,최홍주 한국농업교육학회 2007 농업교육과 인적자원개발 Vol.39 No.3

이 연구는 새터민의 고용현황 및 문제점을 고찰하고 새터민의 기초직업능력을 진단하여 직업능력개발 방향에 있어 시사점을 제공하는데 그 목적이 있었다. 새터민의 기초직업능력 진단을 위한 도구는 관련 문헌 고찰과 pilot test 및 새터민 교육ㆍ지원 담당자의 안면타당도 검증 등을 통하여 개발되었다. 연구의 목적을 달성하기 위하여 현재 하나원에서 사회 적응교육 및 직업교육을 받고 있는 새터민의 기초직업능력을 진단함으로써 우리나라에 거주하는 새터민의 기초직업능력을 파악하였다. 주요 결과는 다음과 같다. 첫째,새터민들의 기초직업능력 중에서 직업윤리능력은 상당히 갖추어져 있는 것으로 인식하고 있으며,정보능력,즉 컴퓨터 사용능력은 상대적으로 낮은 수준으로 평가하고 있다. 둘째,성별에 따라서는 기초직업능력에 있어서 통계적으로 유의미한 차이를 보이지 않았다. 연령에 따라서는 정보능력과 수리 능력,조직이해능력 영역에 있어서 통계적으로 유의미한 차이를 보였다. 셋째,학력에 따라서는 문제해결능력과 의사소통능력,수리능력,대인관계 영역에 있어서 통계적으로 유의미한 차이를 보였다. 넷째,새터민의 취업을 위한 기초직업능력 개발에 있어 정보능력,수리능력,의사소통능력의 비중 확대,수준별ㆍ맞춤형 교육프로그램개발,새터민을 위한 취업 및 사업정보 제공 등을 제시하였다. The purpose of this study was to explore the current employment status and HRD issues of North Korean refugees and to assess their level of the basic vocational competencies. The assessment tool for the basic vocational competencies was developed based on literature reviews and pilot tests from the North Korean refugees. The face validity was verified by educators and counselors for the North Korean refugees. The major findings in this study were as follows: First, among the basic vocational competencies of the North Korean refugees, the level of vocational ethics was the highest and the level of information teachnology competency was the lowest. Second, the North Korean refugees' basic vocational competencies showed no statistical differences by gender. Territories of information competency, mathematical competency, and communication competency showed statistical differences by age. Third, territories of problem-solving competency, communication competency, mathematical competency, mathematical competency, and communication competency showed statistical differences by education level. Fourth, to develop the basic vocational competencies for North Korean refugees, the following suggestions were presented.; 1) extend the importance of information technology, mathematical, and communication competencies,; 2) develop the customized training programs by competency level,; and 3) offer the employment information for North Korean refugees.

주의력 결핍·과잉행동장애 소년의 자기공명 영상을 이용한 뇌량 및 측뇌실의 계량적 특성분석

이정섭,홍강의,김주한 大韓神經精神醫學會 1997 신경정신의학 Vol.36 No.2

By means of retrospecitive quantitative neuroanatomic imaging, the authors assessed the corpus callosum and the lateral venticle in the boys with attention deficit hyperactivity disorder(ADHD). The midsagittal cross-sectional area of the corpus callosum, divided into seven regions, and the axial ventricle-brain ratio were measured from magnetic resonance images of 18 boys with ADHD and 15 comparison boys. Two anterior regions, the genu and the rostral body, were found to have significantly smaller areas in the ADHD boys. There was no significant difference in ventricle-brain ratio between ADHD and comparison boys. This finding supports the theory of abnormal frontal lobe development in ADHD.

Advanced Indentation System을 이용한 연성 파괴인성 평가식의 모델링

주장복,이정석,심홍석,이승건,권동일 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.1

Fracture properties of various structural steels were determined non-destructively using the advanced indentation system (AIS), which is developed on the basis of continuous indentation technique. In this study, conventional critical strain model was modified to predict the ductile fracture toughness from the AIS data. In deriving the ductile fracture toughness model, fracture strain and characteristic length were estimated using the stress triaxiality and the work-hardening exponent. AIS tests were conducted on carbon steels, stainless steels, aluminum alloys and copper alloys. For all these materials, the results of indentation test were compared to those of the standard fracture toughness test methods, which shows that the present analysis can predict successfully the ductile fracture toughness of structural steels.

실드공법에 의한 도심지 터널의 해석

이홍주,김수석,진치섭 釜山大學校 都市問題硏究所 1997 都市硏究報 Vol.5 No.-

The use of underground space has been increased according as area of city has been limited by the urban concentration of population. So it was demanded to increasing tunnel, but this tunnel construction was made trouble in open cut method which has been used generally. Consequently, shield tunneling method is highlighting in urban civil. In the past decade soft clay shield tunneling technology have been improved to permit continuous support to the face of a tunnel. These advanced shield can be operated such that in initial heaving is created, this helps to decrease the inward soil movement into the tail void. In this paper, the measurement of slurry shield and EPB shield were used and two dimensional elasto-plastic programs EPSHILD developed for shield tunnel analysis were approved. The excavation steps corresponding with construction stages were settled and heaving load, load factors were considered. This study is based on the instantaneous settlement which is occured in the process of shield construction but not the secondary settlement by consolidation.