슬러지 건조로 설계를 위한 3차원 CFD 모델 개발

전영남,송형운,백원석 조선대학교 환경공해연구소 2006 環境公害硏究 Vol.19 No.1

The purpose of this study lies primarily on the development of the sludge dryer for the dehydrated sludge of moisture content with 70~80 wt.%. The sludge dryer was modified from the rotary kiln type dryer. A numerical simulation on the thermal flow performance in the sludge dryer was carried out to investigate the design factor and operating conditions, Parametric screening studies were carried out for variations of the following variables: dryer shape, injection length of combustion air, velocity of combustion air, temperature of combustion air. By predictive results, the sludge dryer has a good drying characteristics so that input sludge increased with retention time by recirculation zone of high temperature combustion gas in the bed of sludge dryer. Parametric screening studies have been conducted to study optimal dryer shape and operating condition.

저 발열량 페유 소각기 개발에 관한 실험적 연구

전영남,백원석,송형운,유경석,김성천 조선대학교 환경공해연구소 2004 環境公害硏究 Vol.18 No.-

The advanced waste oil incinerator is suggested that has heat recirculation region in the combustor to burn out the waste oil completely in high temperature zone and heat recuperator in the left side of combustion cavity which plays a role of the flame stabilization of main burner flame by heat recovery of exhaust gas to incinerate waste oil contained water. In order to investigate a simultaneously incineration efficiency of the vessel waste oil contained the hazardous waste which occurs from the vessel and the sea outflow waste oil experiments have been carried out using the emulsion fuel mixed the water and bunker fuel oil C and the blend mixed the light oil and the waste surrogate material (acetonitrile:CH_(3)CN). The results of experiments showed that the waste oil incinerator developed in this study was excellent for the incineration efficiency of waste oil at an air ratio of 1.46 and DRE (destruction and removal efficiencies) of CH_(3)CN was 99.9996% ("5 nines"). And optimum operating conditions for the secondary air flow rate of internal mix burner, preheating temperature and injection point of shipboard waste oil contained acetonitrile were suggested.

흰쥐의 감각신경절세포에 대한 Methylmercuric chloride의 독성효과

鄭榮吉,白承和,韓斗錫,柳道坤,朴承澤 한국전통의학연구소 1998 한국전통의학지 Vol.8 No.1

흰쥐의 배양 척수감각신경절세포에 대한 methylmercuric chloride(MMC)의 세포독성을 조사하기 위하여 여러 농도의 MMC가 포함된 배앙액에서 24시간 동안 배양한 후 MTI assay법에 의하여 세포의 생존율을 조사하였다. MMC는 농도에 비례하여 세포의 생존율을 감소시켰다. 또한 여러 농도의 MMC가 포함된 배앙액에서 흰쥐의 척수 감각신경절(dorsal root ganglion, DRG) 세포를 24시간 동안 처리한 결과 MTI_(50) 값이 25μM MMC에서 나타났다. MMC는 Borenfreund등(1988)의 독성판정기준에 의하여 흰쥐의 배앙 DRG 세포에 고독성인 것으로 나타났다. 이상의 결과는 MMC가 흰쥐의 배양 척수감각신경절세포에 강한 신경독성 효과가 있음을 제시하였으며 또한 배양신경세포는 약제의 효과를 검색하는데 효과적이었다. To examine the cytotoxic effect of methyl mercuric chloride(MMC) on the cultured rat spinal dorsal root ganglion(ORG) neurons, cell viability was measured by MTT assay after rat spinal ORG neurons were incubated with media containing various concentrations of MMC for 24 hours The results were as follows ; 1. MMC decresed cell viability of rat spinal ORG neurons in a dose-dependent manner. 2. MIT_(950) value was a 25uM MMC after spinal ORG neurons were cultured for 24 hours at various concentrations of MMC. 3. MMC was heighly toxic on the cultured ORG neurons by the toxic criteria of Borenfreund et al.(1988). From above the results, it is suggested that methylmercury involves in neurotoxicity by the decrease of cell viability in cultured rat spinal DRG neurons, and cultured neurons are effective in screening the putative agents.

Chlorhexidine varnish 처치 후 고정식 교정장치 장착 환자의 치태내 균주 변화 양상에 대한 장기간 관찰 연구

장영일,양원식,남동석,김태우,백승학 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.3

본 연구의 목적은 chlorhexidine varnish를 고정식 교정장치 장착 환자의 치면에 도포한 후 나타나는 치태내 균주의 변화 양상을 장기간 관찰하는 것이다. 서울대학교병원 치과진료부 교정과에서 고정식 교정장치로 치료하기로 하였던 환자 100명중에서 32주까지 장기간 추적 (follow-up) 되었던 21명을 최종 연구대상으로 선정 하였다. 실험군(12명)은 chlorhexidine varnish를 1주일 간격으로 4회 도포한 후 고정식 교정장치를 부착하였고, 대조군(9명)은 chlorhexidine varnish처치를 하지 않고 고정식 교정장치를 부착하였다. 그리고 실험군에서는 20주 째에 chlorhexidine varnish를 1회 처치하였다. 두 군에서 고정식 교정장치 부착 직전과 부착 후 4, 8, 20, 32주의 치태내 균주의 변화 양상을 간접면역 형광 현미경법으로 분석하고 SAS 통계프로그램을 사용하여 다음과 같은 결과를 얻었다. 1.Streptococcus mutans는 실험군에서 전 실험기간동안 통계학적으로 유의성 있게 억제되었고 (p〈0.01), 대조군에서 전 실험기간동안 통계학적으로 유의성 있게 증가하였다 (p〈0.05). 2.Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, Actinomyces naeslundii는 실험군과 대조군에서 통계학적으로 유의성 있는 변화를 보이지 않았다. 따라서 고정식 교정장치를 사용할 환자에서 chlorhexidine varnish를 처치할 경우 치아 우식의 주 원인균인 Streptococcus mutants를 장기간 선택적으로 억제할 수 있을 것으로 생각된다. The authors observed the long term effects of chlorhexidine vanish treatment on microbial change of dental plaque in orthodontic patients with fixed appliances. The initial sample was 100 patients who were arranged to be treated with fixed orthodontic appliances. The final sample consisted of 21 patients who could be traced for 32 weeks after application of fixed orthodontic appliances. They were classified into the experimental group (12 patients) and the control group (9 patients). The experimental group was treated with chlorhexidine vanish once a week for 4 weeks before application of fixed orthodontic appliance. The control group was not treated with chlorhexidine varnish before application of fixed orthodontic appliance. The experimental group was treated once more after 20 weeks. The microbial changes of dental plaque were analysed by indirect immunofluorescence technique at pre-treatment, post-treatment 4, 8, 20, and 32 weeks. The results were as follows. 1.In the experimental group, streptococus mutans was significantly suppressed during experimental period.(p〈0.01) But, in the control group, streptococcus mutants was significantly increased after placement of fixed orthodontic appliances during experiment period.(p〈0.05) 2.Streptococcus sanglus, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii did not show significant change between the experimental and the control group during experiment period. So, if we treat the orthodontic patients with chlorhexidine varnish before application of fixed appliances, we may suppress the major cariogenic bacteria, Streptococcus mutans, selectively for long period.

저공해 사이클론 연소기 설계를 위한 유동해석 연구

전영남,백원석,김승호,김미환 조선대학교 환경연구소 2001 環境硏究 Vol.17 No.2

Cyclone combustors are being used for burning a wide range of fuel such as, low calorific value gas, waste water, sludge, coal, etc. The 3-dimensional swirling flow in a tangential inlet cyclone combustor with different inlet conditions and dimensions are simulated using a standard k-e turbulence model. The main parameters considered in this work are inlet velocity, inlet number, exit diameter, body length, vortex finder length and inlet area. The results show that the change of parameters has an influence on the shape and size of recirculation zones, vortex core and flow field, which are important factors for combustion efficiency and emissions. The application of this kind of computer program looks promising as a potential tool for optimum design of a cyclone combustor with high level of the swirling flow.

기도 이물의 임상적 고찰

김영석,이승규,이민재,백병준,오천환 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.2

Aspiration of foreign bodies into the airway is a common problem in spite of efforts to educate the public and it can be sometimes fatal accidents. A retrospective study has been performed for 34 cases of airway foreign bodies, which were obtained from April 1994 to August 1998 at Chunan hospital of Soonchunhyang University. The results were as follows: 1) Among the 34 cases, 26 cases(76.4%) were under the age of 3. The ratio of male and female was 1.4:1. 2) The most common symptom after foreign body aspiration was intractable cough(38.2%). 3) Abnormal findings in the chest X-ray films were found 24 cases(70.6%) and the most common abnormal radiologic feature was combination of pneumonia and atelectasis(37.5%), followed by combination of pneumonia and emphysema(16.6%), pneumonia alone(16.6%). 4) The nature of foreign body was vegetables in 20 cases(58.8%), miscellaneous in 11 cases(32.4%), metals in 2 cases(5.9%) and plastics in 2 cases(5.9%). 5) By distribution of the location of foreign bodies, 26 cases(76.4%) were located in the main bronchus(20 cases in right side and 6 cases in left side), 5 cases were in trachea, 2 cases were in larynx and 1 case was located at carina level. 6) By duration of foreign body lodgement in the airway, 15 cases(44.1%) were found within 24 hours, 9 cases(26.5%) were within 7 days, 7 cases(20.6%) were within 30 days and 3 cases(8.8%) were found over 1 month. 7) In mode of treatment, ventilating bronchoscopic removal under general anesthesia was performed in 29 cases(85.3%), thoracotomy with bronchotomy in 2 cases, thoracotomy with lobectomy in 1 case and postural drainage in 2 cases. 8) Complication rate according to the nature of foreign body was most high in vegetables(68.2%). 9) Correlation between complication rate and the duration of the foreign bodies in situ was definite.

노인 인구에서 신경인지기능저하와 혈청 지질농도와의 상관성

유영선,최석주,정성수,김지은,윤성욱,전동욱,백준형,박성우,이정구,추일한,김영훈 大韓神經精神醫學會 2008 신경정신의학 Vol.47 No.6

Objectives : In this study, the authors evaluated the correlation between eurocognitive impairments and serum lipids levels among Korean elderly over the age of 65. Methods : A total of 609 elderly individuals participated in this study. Screening for cognitive impairments were carried out using the Mini-Mental Status Examination-Korean version (MMSE-KC). There were 197 subjects above 1.5SD Of MMSE- KC and they were evaluated using the Korean versions of the Consortium to Establish a Registry for Alzheimer's Disease (AD) (CERAD-KC) and Geriatric Depression Scale (GDS-K). Results : There was a correlation between old age/low levels of education and AD (p<0.05, P<0.01). There was an inverse correlation between the serum level of total cholesterol and the word list recognition test scores. The serum levels of LDL cholesterol were inversely correlated with the scores on the constructional praxis test, word list recall test and word list recognition test. Inverse correlations between the serum level of triglyceride and scores on the word list recall test and word list recognition test were also observed. Conclusion : There were inverse correlations between the serum levels of lipids and language/memory function in subjects with AD.

晉州 附近 新洞層群(下部 白堊系)에서 産出되는 化石 Stromatolite의 生堆積 構造 및 古環境

金榮汶,白光錫,徐承祚 晋州敎育大學校 科學敎育硏究所 1998 科學敎育硏究 Vol.24 No.-

For the purpose of clarifying the organosedimentary structure and paleoenvironment of stromatolites from the southem part of the Kyongsang Basin, the study was carried out both through the field works and chemical analysis of samples. Obtained data were compared with the repotred ones from areas in North Kyongsang Province, additionally. Through this study, the paleaoenvironments of these areas were summarized as follows: 1. Laminations of stromatolite are consist of algal-rich and sediment-rich laminae altemately. The content of calcite, main component of stromatolite, has less Magnesium value. Thus, it seems to have formed under the fresh water environment. 2. The almost of the stromatolites have very irregular shapes which has been caused by disturbed and divided algae from microbial activities. Therefore, it can be inferred that the lake was calm. 3. It seems to have been shallow lacustrine environment and intermittent dry season.

한국인 반안면 왜소증 환자의 유치와 영구치 크기에 관한 연구

장영일,양원식,남동석,김태우,백승학 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.1

반안면 왜소증 (Hemifacial microsomia) 은 선천성 악안면기형 중 발생빈도가 두 번째로 높은 질환으로서, 상, 하악골 뿐만이 아니라 외이나 중이, 두개의 일부, 협부 연조직, 안면신경, 근육 등의 복합적인 부위를 침범하는 광범위한 선천성 기형으로서, 환자에 따라 그 정도의 차이는 있으나 성장에 따라 교합면 경사와 함께 이환 측으로 안면 비대칭의 정도가 점점 심화되는 특징을 가진다. 반안면 왜소증에서 치아와 관련된 증상으로는 치아 성숙도의 차이, 치아 수의 감소, 맹출지연, 법랑질 저형성증 등이 보고된 바 있다. 치아는 악골의 크기나 형태와 밀접한 연관을 가지고 발육하기 때문에, 반안면 왜소증 환자의 경우 치아 발육에서 변화가 발생되기 쉬울 것으로 생각된다. 이에 저자들은 한국인 편측성 반안면 왜소증 환자의 이환 측과 비이환 측에서 상, 하악 유치와 영구치의 크기와 형태 차이 여부를 조사하기 위하여 본 연구를 시행하였다. 서울대학교병원 교정과에 내원하였던 편측성 반안면 왜소증 환자 34명 (남자 18명, 여자 16명, 초진시 평균연령 5세 11개월)을 연구대상으로 선정하였다. 이들의 각 치아별 근원심과 협설측 폭경을 계측한 후, 평균 및 표준편차를 계산하고 paired t-test로 통계 처리하여 다음과 같은 결과를 얻었다. 1.상, 하악 유치와 영구치의 이환 측과 비이환 측의 근원심 폭경 비교에서 이환 측의 하악 제 2 유구치와 하악 제 1 영구 대구치가 비이환 측에 비하여 작게 나타났으며 통계학적 유의차를 보였다. 이것은 하악 전치부와 제 1 유구치의 근원심 폭경에서 통계학적으로 유의성있는 차이를 보이지 않았음과 연관지어볼 때, 이환측 하악의 최후방 구치에서 근원심 폭경 감소의 경향 (gradient of severity)이 크다고 할 수 있다. 2.상, 하악 유치와 영구치의 이환 측과 비이환 측의 협설측 폭경 비교에서 모든 치아에서 통계학적 유의차를 볼 수 없었지만, 이환 측의 하악 유치와 영구치의 협설측 폭경이 비이환 측에 비하여 보상적으로 다소 큰 값을 나타내는 경향이 있었다. 본 연구는 반안면 왜소증에 의하여 영향을 받은 하악골의 이환측 치아, 특히 최후방 구치, 의 크기와 형태 이상이 발생될 가능성이 있다는 것을 보여주었다. Hemifacial microsomia (HFM) is the second most common craniofacial abnormalies. HFM represnted a spectrum of clinical findings such as hypoplasia of the mandibular ramus and condyle, confinement of maxilla growth, external and/or middle ear defects, involvement of some cranial suture, buccal soft tissue, facial nerve, and muscles in the affected side. HFM often showed progressive facial asymmetry and occlusal plane slanting to the affected side with growth. There were several reports about asymmetry of tooth maturation, hypodontia, delayed eruption, enamel hypoplasia in HFM. Since teeth develope in close association with size and morphology of the maxilla and the mandible, it is highly likely that dental changes will be present in HFM. So the purpose of this study was to investigate the differences of the primary and the permanent teeth dimensions in the maxillary and the mandibular dentition between the affected and the non-affected side of HFM. The sample of this study consisted of 34 unilateral HFM patients (18 males and 16 females, average age : 5 year 11 months old). The authors examined the mesiodistal and the faciolingual dimensions of the primary and the permanent teeth and performed statistical study by using paired t-test. The results were as follows : 1.The mesiodistal dimensions of the mandibular second primary molar and the mandibular first permanent molar in the affected side of HFM were significantly smaller than those of non-affected side. But there were no significant differences in the anterior teeth and the mandibular first primary molar. It means that a gradient of severity from anterior teeth to posterior teeth was found in the mandibular dentition. 2.Although there were no significant differences in the faciolingual dimensions of the primary and the permanent teeth in the maxillary and the mandibular dentition between the affected and non-affected side of HFM, there were general trend of compensatory increase in faciolingual dimension the mandibular primary and the permanent teeth in the affected side. Therefore these results showed that HFM might affect on the abnormality of tooth dimension, especially the most posterior teeth, in the affected side of the mandible.

전신경화증에서 관상동맥 경화증에 대한 예비 연구

박영은,백승훈,정연주,추기석,김성일 부산대학교 병원 암연구소 2009 부산대병원학술지 Vol.- No.25