Algal bioassay 에 의한 조류생장 제한영양염류 결정

오희목(Hee Mock Oh),이석준(Seog June Lee),김성빈(Seong Bin Kim),박미경(Mi Kyung Park),윤병대(Byung Dae Yoon),김도한(Do Han Kim) 한국하천호수학회 1998 생태와 환경 Vol.31 No.2

Determination of Limiting Nutrient for Algal Growth by Algal Bioassay. Oh, Hee-Mock, Seog June Lee, Seong-Bin Kim, Mi- Kyung Park, Byung-Dae Yoon and Do-Han Kim (Environmental Microbiology Research Unit, Korea Research Institute of Bioscience and Biotechnology, Taejon 305-333, Korea and Water Resources Research Institute, Korea Water Resources Corporation, Taejon 305-390, Korea) Water quaiity and algal growth potential (AGP) using Microcystis aeruginosa were investigated from April to September 1997 in Daechung Reservoir. Secchi disk transparency was 1.1 m in August. Chlorophyll-a concentrations were higher than 10㎍/l at all samples. Total phosphorus concentration was in a range of 0.020∼0.027mg/l which is at the approximate value of 0.03 mg/l, the general critical level of eutrophication. These results indicate that Daechung Reservoir is in an eutrophic state except some temporary times and restricted sites. Phosphorus uptake rate of M. aeruginosa was higher in the water from the epilimnion than in the hypolimnion and also higher under light condition than under dark condition. Therefore, phosphorus uptake rate appears to depend on cellular phosphorous content and light condition, a meaning of endergonic process. Phosphorus was the most frequently limiting nutrient: phosphorus was limiting algal gowth in April and May, nitrogen, phosphorus and trace elements were the limiting factors for algae in August, and trace elements in September. If a fast growing alga, M, aeruginosa, is used as a test organism for assaying AGP, in vivo fluorescence instead of dry weight can be measured for algal biomass and incubation period can be reduced from traditional 14 days to 7 days.

좌골신경손상 흰쥐의 가자미근과 내측비복근 위축에 대한 전기자극 효과

박병림,허우회,유병표,김영우,김대영 대한성형외과학회 1992 Archives of Plastic Surgery Vol.19 No.3

This experimental study includes the effect of intermittent electrical stimulation of the muscle on the atrophic response of peripherally denervated muscles. Rats(Sprague -Dawley, 240-260gm) were subjected to a severance of the sciatic nerve and mechanical properties of contraction including contraction time, half relaxation time and maximum twitch tension, maximum tetanic tension and fatigue index were observed on the slow(soleus m.) and fast(medial gastrocnemius m.) muscles 10days after serverance of the sciatic nerve. Experimental groups were divided into three groups : control group(CONT) immediately after severance of sciatic nerve, denervation group(DN) 10days after severance of sciatic nerve, and denervation plus eletrical stimulation group : (DN-ES) denervation combined with intermittent eletrical stimulation of muscles directly. Optimal frequency of electrical stimulation was 20㎐ for soleus muscle and 40㎐ for medial gastrocnemius muscle under 0.5ms of pulse width and supramaximal intensity. In DN group, muscle weight and mechanincal properties of contraction were significantly decreased compared with the control group. In DN-ES group, however, muscle weight and mechanincal properties were significantly increased compared with the denervation group. These data indicate that intermittent electrical stimulation of muscles may be useful in decreasing the muscle atrophy in peripherally denervated muscles.

교차로계획에서 현대식 회전교차로(Modern Roundabout)의 도입 타당성

박병호,송대섭 충북대학교 건설기술연구소 2003 建設技術論文集 Vol.22 No.2

This study deals with the rationalities of modern roundabouts in the intersection planning. The goals are three-folds: (1) to compare modern roundabouts with the traditional traffic circles, and (2) to describe the types of modern roundabouts, and (3) to analyze the effectiveness of introducing the modern roundabouts to the intersection planning. The main results are as follows. Frist, the modern roundabouts have such the merits as improved safety, shorter delay, increased capacity and aesthetics compared to the traffic circles. Secondly, the modern roundabouts are described as six types of roundabouts according to the entering speed, number of lane, capacities and others. Finally, the literature survey shows that the roundabouts have such the general effects as the improved safety, decreased delay, urban aesthetics and other.

親電子性 芳香族 置換反應의 轉移狀態에 關한 理論的 硏究

朴柄珏,郭庚度,宋寧大 嶺南大學校 基礎科學硏究所 1991 基礎科學硏究 Vol.11 No.-

The transition state for electrophilic aromatic substitution was estimated by EHMO and CNDO/2 method. The transition state has been found to be δ-complex like model rather than π-complex like model for the substitution of a hydrogen in benzene with both proton and brominum ion. The electronic energies of δ-complex like models revealed the parallelism between the observed rate constant and the number of the substituted methyl groups in benzene. Consequetly, it can be generally thought that electrophilic aromatic substitution proceeds via δ-complex like model.

경주 최부자 가문의 양택을 통해 본 풍수인식에 관한 연구

박성대,양삼열,김병우 부산대학교 한국민족문화연구소 2013 한국민족문화 Vol.47 No.-

The purpose of this study is to research the feng-shui theory reflected in the philosophy of the Choi family upper class by analyzing the conditions of the feng-shui locations of the family-related sites. For this purpose, two residential areas(Chunguidang and Choi's Old House) have been selected. This study shows that two locations are highly suitable to feng-shui theory. The Choi family upper class was a Sajok during the Joseon dynasty in the Gyeong-Ju region who understood feng-shui theory very well. Their recognition of feng-shui was expressed via their search for the best site(Myungdang) and their application of the Bibo concept to improve minor defects in their settlement area in terms of feng-shui. This study is limited to analysis of two residential areas of the Choi family except their graves. Nevertheless, this study shows a part of recognitions of feng-shui of Sajok during the Joseon dynasty in the Gyeong-Ju region. This study helps people better understand the philosophy and thought of the Choi family upper class. 본 연구의 목적은 경주 최부자 가문 유적지의 風水적 특성을 분석하고, 이에 담겨 있는 최부자 가문의 풍수적 인식을 고찰하는 것이다. 이를 위한 연구대상으로 최부자 가문의 주요 양택지 두 곳인 내남 이조리 충의당과 교동 고택을 선정하였다.연구 결과, 충의당과 교동 고택 모두 양택지로서의 길지 조건을 갖추고 있었다. 이를 통해 조선시대 경주지역 사족인 최부자 가문 역시 그들의 생활 철학 속에 풍수적 인식을 상당 부분 보유하고 있었으며, 이러한 풍수적인식이 吉地를 찾고 定住地의 풍수적 결함을 裨補하는 등의 실제적인 노력으로 표출되었음을 알 수 있었다. 그리고 그들의 풍수적 인식이 교동 시대인 조선 후기로 갈수록 발전하였음을 알 수 있었다. 본 연구의 한계점은 최부자 가문의 양택에만 국한된 분석이며, 음택을 연구 대상에서 제외시킨 것이다. 그럼에도 불구하고 본 연구는 조선후기 경주지역 사족의 풍수 인식의 일면을 보여주고, 동시에 최부자 가문의 생활철학과 사상에 대한 이해를 한층 높이는 데에도 일조할 수 있다는 데에 본 연구의 의의가 있다 하겠다.

복합레진의 중합 수축력과 수복물의 결합양상에 관한 연구 제 1 편 : 중합수축력

박남수,최대균,임호남,최부병,우이형 大韓齒科器材學會 1993 대한치과재료학회지 Vol.20 No.1

The polymerization contraction forces has a relationship with the contents of filler, and if forces surpass the bond strength between restoration and bonded surface, the failure of bond can be occured. This study was designed to evaluate the effects of filler contents on the polymerization contraction forces and to confirm whether the polymerization forces could induce the bond failure of composite resins to enamel or dentin. Low capacity load cell using strain gauge were prepared and used as a measurement system for polymerization contraction forces. Oxidized alloy surfaces, enamel surfaces and dentin surfaces were used as bonded surface. Measurements of the polymerization contraction forces were done for 1 hour, and a stress at 1 hour after was recorded as a polymerization contraction force. It was considered as a bond failure that the polymerization contraction forces increased and then decreased by the time. The following conclusions were drawn : 1. Polymerization contraction forces of composite resins were decreased by the increase of filler contents. 2. Polymerization contraction forces were increased at thickened resin specimens, but it was not significant at over two millimeter thickness. 3. Bond strength of composite resins to the acid etched enamel surfaces exceeded the polymerization contraction forces and the reduced polymerization contraction forces due to the bond failure were not confirmed. 4. Failure of bond and reduced polymerization contraction forces occured on dentin.

표준 용매 벤젠의 Rayleigh 비의 온도 의존성

박일현,이종근,윤관한,조동환,민병길,방대석 金烏工科大學校 2000 論文集 Vol.21 No.-

The Rayleigh ratio of benzene is a very important physical constant with which the integrated scattered intensity of laser light scattering can be converted into the absolute value. In this study temperature dependence of Rayleigh ratio of this solvent has been investigated with two different methods in the temperature range of 25-75℃. It was found that in the direct measurement the non-linear behavior of its Rayleigh ratio were observed as increasing temperature even if the scattering volume correction was applied to the scattered intensity of benzene. However the result of indirect measurement based upon the invariance of molecular weight of standard polystyrene polymer for any polymer solution temperature showed us that its temperature dependence up to 75℃ could be expressed with the Benoit's linear equation rather than the non-linear one. It seems that the scattered intensity in direct method has more complicate contributions at the elevated temperature. Further research works are necessary in order to solve such discrepancy clearly.

대학수학능력시험 도입후의 고교교육 변화에 관한 연구

박병량,변영계,한대동,성병창 교육연구소 1994 敎育硏究 Vol.4 No.1

Under the current school system in which secondary schools aim at the preparation for college entrance, the college entrance examination has a crucial impact on high school education. The former college entrance examination has been accused of causing many problems in high school education such as training students, in a recital mode, by giving fragmentary knowledges and skills picked up by teachers largely for the college entrance emanination. Under the examination system students were not recommended either in school or at home to pursue their own interests and concerns which are supposed to enhance higher order thinking including creativity. In order to reform this change-resisting high school education a new type of college entrance examination called College Scholastic Aptitude Test (CSAT, hereafter) replaced the former one in 1990 in the worldwide tide of educational reform toward the quality education. This study is to examine whether and/or to what extent the newly introduced CSAT has brougght changes to high school education. This study began with two concrete research problems. First, to what degree did the CSAT affect high school students particularly in the areas of attitudes toward school, classroom learning and instruction, and study habits? This refers to personal effects separated from school education. Second, to what extent did the CSAT make changes in high school education? This refers to institutional effects. As a survey, this study collected questionnaire data from 1,600 male and female high school third graders from 33 high schools locatedin Pusan City and its surrounding KyungNam-Do province. The CSAT was firstly introduced in 1990 when the survey respondents were then high school freshmen. The sample method is a systematic cluster random sample. After schools had been randomly selected about 60 students(2 classes) were sampled from each school. The questionnaire consisted of questions asking largely whether any changes were made in the areas such as individual student's studying strategies and their perceptions of schooling. The students' responses were analyzed according to concrete research problems using appropriate statistical methods. The research results are summarized as follows. First, according to students' responses they evaluated that CSAT was somewhat successful in measuring higher order thinking and somewhat conducive to lessening social problems cuased by excessively competitive high-cost private lessons. The new exam, however, unexpectedly did not have affirmative effects on such areas as: undesirable operation of high school; measurement of learning ability; selection of college qualifiers; and test item difficulty and discrimination. Second, the effects of CSAT on school-based tests were found to be both slightly positive and negative. For the positive side of the effects, the test content was not confined to textbooks but taken either from other non-text sources or from what was taught in classrooms beside textbooks; in solving the test questions not only correct answers were not required but also the problem-solving processess were also emphasized in schools. In following areas, however, there were almost no changes made: the dominance of multiple-choice test items; anxiety of testers; the utilization of test results for own learning improvement; and the frequent school testing. Third, since the introduction of CSAT there have been almost no improvements in school organizational practices, management, and climates such as; extracurricular activities, communications with teachers, guidance and discipline, teachers' expectations of students, grouping of students according to ability and talent, and friendship among classmates. One exception was that classroom climate has become somewhat open and democratic than before. Fourth, with regard to classroom activities some improvements have been detected. The classroom instruction has been somewhat changed into one emphasizing higher order thinking. It was revealed through teachers' efforts to employ new teaching methods and to carry out curriculum in a regular basis, to try to upgrade expectations of students, and to make classroom learning more explorative. On the other hand, in other areas of classroom activities it was hard to find any noticeable improvements. Finally, it was the area of individual student's studying methods and attitudes that the most noticeable changes were found since the introduction of CSAT. To mention some of them, the dependency on private lessons and private academic institutes was much lessened; the learning materials were varied beside school textbooks; the students' autonomy has been increased in the area of learning need and motivations, studying strategy from memorizing to understanding, and selecting educational or occupational careers based on one's own character and talent. As a result, the introduction of CSAT seems to give student more confidence in studying and learning. Compared to these changes in individual-based studying attitudes, perceptions and learning methods connected to schooling did not change noticeably. This contrasting finding is in a sense a main point of this study. All in all, and in short, the introduction of the new College Scholastic Aptitude Test (CSAT) were somewhat effective in changing individual students' studying or learning attitudes, methods, and strategies in preparation for college entrance, but it was found to be unexpectedly ineffective in improving institutionally school organizational practices, instructional methods, guidance and disciplines, curricular implementation, and other school management and operations. This result reminds us a fact that and educational policy could not be easily rooted in the practical soil.

복합레진의 중합 수축력과 수복물의 결합양상에 관한 연구 제 2 편 결합강도

박남수,우이형,최부병,임호남,최대균 大韓齒科器材學會 1993 대한치과재료학회지 Vol.20 No.2

Failure of bond between resinous restorative materials and tooth can be occured by the polymerization contraction forces larger than bond strengths. This study was planned to confirmed that the bond strengths between composite resin and acid etched enamel will be influenced by the polymerization contraction forces altered with filler contents and diameter of attached resin specimens. Ten kinds of experimental composite resins were prepared and bonded to bovine tooth enamel which were acid-etched. The diameter of resin specimens attached were 4 mm and 6 mm. The following conclusions were drawn : 1. Shear bond strengths were increased and then decreased with rise of filler contents, maximum shear bond strength was obtained by the 40% filled composite resin. 2. Unit shear bond strengths of resin specimens bonded with large area were lower than that of narrow area bonding. It was concluded that shear bond strengths to acid etched enamel can be influenced by the polymerization contraction forces.

香砂平胃散 및 當歸活血湯이 膽道結紮과 Dimethylnitrosamine으로 誘發된 白鼠의 肝硬變症에 미치는 影響

박대영,姜秉淇 圓光大學校 韓醫學硏究所 1995 원광한의학 Vol.5 No.1

This study was to investigate the protective and anticirrhotic effects of Hyangsapyungwuisan and Dangguishalheoltang on the liver cirrhosis or fibrosis induced by prolonged bile duct ligation; a new experimental model for cirrhosis and the intraperitoneal injection of dimethylnitrosamine in the rat. The development of fibrosis or cirrhosis and its inhibition by the two prescriptions were examined by the chemical analysis of AST, ALT, and hydroxyproline, and histological and immunohistochemical observations. The results obtained were as follows. 1. The increase of serum asparate aminotransferase induced by bile duct ligation was inhibited by the administration of Hyangsapyungwuisan and Dnagguiwhalheoltang, especially markedly inhibited in the group of Dangguiwhalheoltang administration. 2. The increase of serum alanine aminotransferase induced by bile duct ligation in rats was inhibited by the administration of Hyangsapyungwuisan and Dangguiwhalheoltang, especially markedly inhibited in the group of Dangguiwhalheoltang administration. In conclusion, the increass of AST, ALT induced by bile duct ligation was efficiently decreased by the administration of Dangguiwhalheoltang extract. 3. The increased level of serum AST and ALT induced by the intraperitoneal injection of dimethylnitrosamine was inhibited by the administration of Hyangsapyungwuisan and Dangguiwhalheoltang extract. But there was no significant differences in the inhibition rate. 4. The incerasing level of hydroxyproline volume in the damaged lever tissues in rat were decreased by the oral administgration of Hyangsapyungwuisan and Dangguiwhalheoltang extract. But there was no significant differences in the inhibition rate between the two experimental groups. 5. The histological observation the damaged liver tissue and immunohistochemical observation of bromodeoxyuridine in the liver tissue of rats showed the significantly hepatoprotective effects of Hyangsapyungwuisan and Dangguiwhalheoltang extract, and resealed the regenerative effects of Hyangsapyungwuisan and Danggui- whalhioltang etract on the damaged liver induced by bile duct ligation and the i.p.injection of dimethylnitrosamine.