폭기형 교반탱크내에서의 열전달에 관한 연구(II)

蔡泳培 건국대학교 1986 論文集 Vol.23 No.1

An experimental investigation of the heat transfer from mechanically agitated gas-liquid dispersions to a helical heating coil has been carry out. Experiments were performed in a flat bottom cylindrical tank (Dt=30cm) with a six-flat blade turbine Impeller (Di=10cm) and loop type nozzle sparger (do=0.1cm, Dn=8, loop height =4Hi/5). Heat transfer coefficients in aerated stirred tank were measured over range of superficial gas velocity (4.7×10-3≤Vs≤1.89) and impeller speed (100≤rpm≤900). An analysis of the experimental results observed that heat transfer coefficients were increased as well as decreased with the impller speeds and superficial gas velocities. But, above the critical impeller speed, air sparging decreased the heat transfer coefficients.

이트리아 첨가 붕규산염 유리로 제조한 알루미나-유리 복합체의 강도 평가

채민수,배태성,이주형,원대희,진영철 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.1

This study was performed to investigate the strength of dental alumina-glass composites. Four different brosilicacte glasses containing 1, 3, 6, 9 mol% Y₂O³ were prepared. Alumina compacts were prepared by pressing 150㎏/㎠ and sintering at 1100℃ for 2 hours. Dense composites were made by infiltrating partially sintered alumina with at 1200℃ for 6 hours. The obtained results were summarized as follows: 1. With increasing the amount of Y₂O₃ the peak of exothermic heat and softening point were shifted to the higher temperature. 2. Borosilicate glasses showed the coefficient of thermal expansion in the range of 6.36 to 6.56×10-6/℃. 3. The maximum biaxial strength of 385.7±34.4MPa was obtained with an addition of 6mol% Y₂O₃. 4. The observation of fracture surfaces showed the crack deflection and crack bridging and that appeared to be the principal strengthening mechanism in the alumina-glass composites.

활석을 이용한 사포나이트의 수열합성

배인국,장영남,채수천,류경원,최상훈 한국광물학회 2003 광물과 암석 (J.Miner.Soc.Korea) Vol.16 No.2

삼팔면체형의 스멕타이트계 사포나이트(saponite)를 천연 광물질인 활석을 이용하여 수열법에 의해 합성하였다. 출발물질은 활석에 Na₂CO₃를 첨가하여 공기중에서 800℃로 가열한 후, 화학양론적 조성에 맞게 Al(No₃)₃·9H₂O 및 Mg(No₃)₂·6H₂O 금속염 수용액을 첨가하였고, pH는 7∼12 범위 내로 NH₄OH 수용액에 의해 조절하여 제조하였다. 수열반응 조건은 약 1리터의 수열반응 용기에서 230 ℃, 압력은 25∼75 kgf/㎠의 범위 내에서 10∼60시간이었다. 실험결과, 반응온도 및 회전속도를 230℃와 180 rpm으로 고정시킨 수열조건 하에서 반응시간, 반응압력, pH 조건을 각각 40시간, 25 kgf/㎠, 약 10으로 하였을 때, 그리고, 화학조성을 화학양론적 조성에 필요한 Na₂O의 양보다 200% 과량 추가하였을 때, 양호한 사포나이트가 합성되었다. 또한 압력을 75 kgf/㎠까지 증가시켜도 결정도에 미치는 영향은 미미하였으며, 반응시간이 길수록 더 좋은 결정도를 나타냈다. Saponite was synthesized from talc by hydrothermal method. The starting material was prepared by adding Al(N0₃)₃·9H₂0 and Mg(N₃)₂·6H₂O solution to the talc powder, which was previously activated in air at 800℃ together with Na₂C0₃. The alkalinity of the solution was controlled by NH₄0H solution. The autoclaving was carried out in the closed stainless steel vessel (about 1 liter) for 40 hours under the pressure of 25 ㎏f/㎠ at 230℃. The characterization of the reaction product shows that saponite was crystallized successfully. After the experimental results, pressure was not sensitive parameter in the range of 25-75 ㎏f/㎠, but longer reaction time results in better crystallinity.

가족성 고콜레스테롤혈증 유병자에서 HMG Co-A Reductasen Inhibitor 및 Bile Acid Resin의 투여로 인한 아킬레스건 황색종의 감소

채인호,한기훈,박영배,조주희,김효수,손대원,김철호,오병희,이명묵,최윤식,서정돈,이영우 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.9

광중합형 복합레진 제조시의 압축강도에 관한 실험적 연구

배태성,추용호,채민수 大韓齒科器材學會 1995 대한치과재료학회지 Vol.22 No.2

This study was performed to elaluate the effect of matrix resins and fillers on the compressive strength of light-activated composite resins. Four different types of composites were made by mixing the inorganic fillers of armorphous spherical silica and crushed quartz with resins of BisGMA/TEGDMA and UTeMA/TEGDMA. The specimens of 3mm in diameter and 6mm in length were prepared. Compressive test was subjected to a crosshead speed of 0.5mm/min and fracture surfaces were examined by SEM. The results obtained were summarized as follows; 1. Compressive strength of the UTeMA-based composite resin with spherical filler was superior to the other composite resins(p<0.01). 2. Compressive strength of the BisGMA-based composite resins with significantly decreased after immersion in water for 7 days(p<0.05). 3. UTeMA-based composite resins showed the aspect of decrease in compressive strength after cold storage at 5℃.

자기 소호형 소자를 사용한 D급 고주파 인버터의 특성 평가 및 설계에 관한 연구

노채균,김동희,김종해,배영호 嶺南大學校 工業技術硏究所 1995 工業技術硏究所論文集 Vol.23 No.2

This paper investigates and compares operating characteristics of the main power conversion circuit and extension of safety operating zone etc in case of use switching device of voltage-fed type high frequency Inverter with self-turn-off device to a case of using nature-commutated type devices. In addition, this paper induced operating characteristics of the main power conversion circuit by examination to normalized parameter. This paper propose that a base data of the main power conversion circuit of characteristics evaluation for frequency characteristics, output characteristics and load characteristics etc.

성인 IgA 신병증의 임상적 고찰

김영학,권용은,허경무,윤채중,김종인,김건영,배학연,정종훈 조선의대 1998 The Medical Journal of Chosun University Vol.23 No.1

디클로로메탄 폭로 광학렌즈 제조업 근로자들의 혈액성상 및 자각증상

조영채,이태용,이동배,박성민 忠南大學校 環境問題硏究所 1997 環境硏究 Vol.15 No.-

This study was performed to find out the changes of hematological values, enzyme activities, and complain rates of subjective symptoms according to the Dichloromethane(DCM) exposure in optical lens manufacturing workers. The DCM exposed workers were divided into 3 groups that were consisted of the washing, setting and seperating group, and analyzed the DCM levels, hematological values(WBC, RBC, Hb, Hct), enzyme activities (s-GOT, s-GPT, TG and TC), and surveyed the subjective symptoms from 42 DCM exposed workers who worked in Taejon city and Chungnam provincial areas from Feb.1 to 18, 1996. The results were as follows: The mean values of DCM were significantly different from working process, that was 19.62±6.29ppm in washing, 25.08±8.27ppm in setting, 43.46±18.65ppm in seperating process. And the DCM exposed levels showed a tendency to increase when job tenure was longer and ventilation was worse. The values of WBC, RBC, s-GOT and TG were significantly increased according to the increase of DCM exposed levels. The complain rates of subjective symptoms of DCM exposed workers were high rates such as "heaviness", "sleepiness","nausea and vomiting". "decrease eye-sight", "hand tremor" and "dyspnea", respectively. The correlation between DCM exposed levels, and WBC, RBC and s-GOT were significantly different, respectively.

통풍성 관절염의 임상적 고찰

윤채중,정승문,김영학,김동규,허광식,김태원,배학연,정종훈,이승일,김평남 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.2

통풍은 Purine 대사의 이상으로 발생하는 질환으로, 고뇨산혈증인 사람의 전부가 통풍으로 발현되지 않고 증상의 출현 양상이 다양하여 진단과 치료에 주의가 필요하며, 조기에 적절한 조치를 한다면 충분히 조절이 가능한 질환이다. 본대학 내과학교실에서는 통풍으로 치료한 32명의 환자에서 임상양상, 병력과 검사소견을 분석하여 다음과 같음 결과를 얻었다. 1. 32명 모두 남자이며, 최초 발병 시기는 24세에서 72세로 평균 43.8±11.9세이었으며, 30대에서 40대까지가 19명(59.4%)으로 대부분을 차지하였다. 내원 당시 나이는 27세에서 75세까지로 평균 52.3±10.4세였으며, 내원시 까지 평균 유병기간은 8.5±6.8년으로 나타났다. 2. 동반 질환으로는 고지혈증 12례, 신장질환 10례, 고혈압 12례, 비만 8례, 당뇨 2례 등이었다. 3. 이환된 관절은 단관절 침범이 19례(59.4%), 다관절 침범이 13례 이었으며, 최초 이한된 관절은 족무지 중족골지골 관절로 19례(59.4%)로 가장 많았고, 통풍 결절은 20례(62.5%)에서 관찰되었으며, 유병기간이 10년 이상된 12례중 11례 (91.7%)에서 결절이 관찰되었다. 4. 평균 혈중 요산치는 9.17±1.75 ㎎/dl이었으며, 8.0 ㎎/dl에서 9.9 ㎎/dl 사이가 19명으로 전체의 59.4%를 차지하였다. Objective: The gout is a heterogeneous group of diseases resulting from tissue deposition of monosodium urate or uric acid crystals from extracellular fluids supersaturated with respect to this end product of human purine metabolism. The clinical manifestations are such as hyperuricemia, gouty arthritis, gouty nephropathy, uric acid nephrolithiasis. We analyze of clinical manifestations and associated factors in gout. Method: We have reviewed the medical records, radiologic findings and clinical results of thirty-two patients admitted at our department from April 1996 to July 1997. Result: 1) All patients were male. The mean age at initial attack was 43.8 years old, ranging from 24 to 72 years old. 2) The mean level of serum uric acid was 9.17mg/dl on admission. 3) The first metatarsopharyngeal joint was involved in 19 cases (59.4%). Tophus was observed in 20 cases (62.5%). 4) Hyperuricemia was associated with hypertension, obesity, nephrolithiasis and hyperlipidemia.

Y-Gd-In-Fe-O계의 분자장 상수와 교환상수의 결정

이영배,채광표 建國大學校 自然科學硏究所 1997 建國自然科學硏究誌 Vol.8 No.-

The substituted Yttrium Iron Garnet(YIG) systems Y-Gd-In-Fe-O have been investigated by means of X-ray diffractometry and SQUID. The specimens have been found to be the cubic garnet structure in the entire compositions. From the magnetization curve measured by means of SQUID and Dionne's formula related to cation distribution, molecular field-and exchange constants were determinated.