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2020 여름 섬진강 대홍수시 하안식생과 수리 특성의 상호관계 (The Interrelationship between Riparian Vegetation and Hydraulic Characteristics during the 2020 Summer Extreme Flood in the Seomjin-gang River, South Korea)

  • 이철호;이건학;김휘래;백동해;김원;김대현;이현재;우효섭;조강현
    • Ecology and Resilient Infrastructure
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    • 제8권2호
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    • pp.79-87
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    • 2021
  • 하천의 하안 생태계에서 식생, 수문 및 지형 사이에 상호작용이 활발하다. 이들 중 하나의 요인의 작은 변화가 다른 두 요인에 큰 영향을 미칠 수 있다. 본 연구에서는 2020년 여름 극심한 홍수로 큰 피해를 입은 섬진강의 선정된 조사지 (가정 2 개 및 하한 2 개)에서 이러한 아이디어를 평가하였다. 특히 원격탐사, 수리 모의, 현장 조사를 결합하여 대홍수시 하안식생과 수리 특성 간의 관계를 조사하였다. 섬진강 조사구간에 위치한 예성교 수위관측소 (영점표고 EL. 27.4 m)에서의 수위는 2020년 8월에 극심한 강우에 의하여 표고 43.1 m까지 상승하였다. 최대 홍수위에서 가정과 하한 조사지의 전단응력은 가정보다 하한에서 4 배 더 높았다. 또한 하안식생이 없을 조건보다 식생이 있는 경우에 대홍수시 수위가 수위가 지점에 따라 최대 1m 정도 상승할 것으로 추정되었다. 조사구간 두 곳 모두에서 대홍수에 의하여 식생 분포면적의 78-80%가 나지로 바뀌면서 광범위한 생물학적 피해를 입었다. 상수리나무와 수고가 낮은 버드나무에 비하여 수고가 높은 버드나무류가 심한 피해를 받았다. 이러한 결과는 모든 하안식물종이 극심한 홍수에 대해 동일한 취약성을 가지고 있지 않으며, 교란에 대해 동일한 종류의 피드백을 나타내지 않는다는 것을 의미한다. 따라서 하안식생의 수목을 효과적으로 관리하는 동시에 의도하지 않게 야기할 수 있는 홍수위험을 최소화하기위한 하천관리 계획이 요청된다.

인간간엽줄기세포의 연골세포 분화 유도 성장인자 및 주사침 크기 차이에 따른 세포반응에 대한 in vitro 연구 (A study of growth factors, chondrogenic differentiation of mesenchymal stem cells and cell response by needle size differences in vitro)

  • 박정윤;황유정;최조셉준석;전진영;이석원
    • 구강회복응용과학지
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    • 제40권1호
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    • pp.13-23
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    • 2024
  • 목적: 인간간엽줄기세포를 연골세포로 분화유도하는 성장인자 규명 및 주사침 크기 차이에 따른 세포증식 증진 비교이다. 연구 재료 및 방법: 인간간엽줄기세포를 연골세포유도배지에서 14, 21, 28일 배양하여 BMP-2, BMP-4, BMP-6, BMP-7, BMP-13, FGF-2, FGF-18, IGF-1, TGF-β1. TGF-β2, TGF-β3를 투여한 군들과 대조군에서 SOX-5, SOX-6, SOX-9 및 FOXO1A의 발현량을 분석하였다. 18, 21, 26 게이지(G) 주사침을 사용하여 배양접시에 인간간엽줄기세포를 접종하고 24, 48, 72시간 후 각각 세포증식을 측정하였다. 결과: 기존에 알려진 FGF, IGF-1, TGFβ1와 함께, BMP-2, BMP-4, BMP-6, BMP-7 등 BMP family 성장인자들에 의하여 연골세포분화 전사인자 유전자들인 SOX-5, SOX-6, SOX-9, FOXO1A의 유전자발현이 증가하였다. 48시간에서는 가장 작은 주사침인 26G군이 대조군 및 18G군에 비하여 유의한 세포증식 증진을 보였으며, 72시간에서도 가장 작은 주사침인 26G군이 대조군에 비하여 유의한 세포증식 증진을 보였다. 결론: 인간간엽줄기세포의 연골세포분화 유도능을 가진 성장인자들을 고찰할 수 있었고 주사침 크기에 따른 세포증식 변화를 규명할 수 있었다.

Design and Implementation of IoT based Low cost, Effective Learning Mechanism for Empowering STEM Education in India

  • Simmi Chawla;Parul Tomar;Sapna Gambhir
    • International Journal of Computer Science & Network Security
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    • 제24권4호
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    • pp.163-169
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    • 2024
  • India is a developing nation and has come with comprehensive way in modernizing its reducing poverty, economy and rising living standards for an outsized fragment of its residents. The STEM (Science, Technology, Engineering, and Mathematics) education plays an important role in it. STEM is an educational curriculum that emphasis on the subjects of "science, technology, engineering, and mathematics". In traditional education scenario, these subjects are taught independently, but according to the educational philosophy of STEM that teaches these subjects together in project-based lessons. STEM helps the students in his holistic development. Youth unemployment is the biggest concern due to lack of adequate skills. There is a huge skill gap behind jobless engineers and the question arises how we can prepare engineers for a better tomorrow? Now a day's Industry 4.0 is a new fourth industrial revolution which is an intelligent networking of machines and processes for industry through ICT. It is based upon the usage of cyber-physical systems and Internet of Things (IoT). Industrial revolution does not influence only production but also educational system as well. IoT in academics is a new revolution to the Internet technology, which introduced "Smartness" in the entire IT infrastructure. To improve socio-economic status of the India students must equipped with 21st century digital skills and Universities, colleges must provide individual learning kits to their students which can help them in enhancing their productivity and learning outcomes. The major goal of this paper is to present a low cost, effective learning mechanism for STEM implementation using Raspberry Pi 3+ model (Single board computer) and Node Red open source visual programming tool which is developed by IBM for wiring hardware devices together. These tools are broadly used to provide hands on experience on IoT fundamentals during teaching and learning. This paper elaborates the appropriateness and the practicality of these concepts via an example by implementing a user interface (UI) and Dashboard in Node-RED where dashboard palette is used for demonstration with switch, slider, gauge and Raspberry pi palette is used to connect with GPIO pins present on Raspberry pi board. An LED light is connected with a GPIO pin as an output pin. In this experiment, it is shown that the Node-Red dashboard is accessing on Raspberry pi and via Smartphone as well. In the final step results are shown in an elaborate manner. Conversely, inadequate Programming skills in students are the biggest challenge because without good programming skills there would be no pioneers in engineering, robotics and other areas. Coding plays an important role to increase the level of knowledge on a wide scale and to encourage the interest of students in coding. Today Python language which is Open source and most demanding languages in the industry in order to know data science and algorithms, understanding computer science would not be possible without science, technology, engineering and math. In this paper a small experiment is also done with an LED light via writing source code in python. These tiny experiments are really helpful to encourage the students and give play way to learn these advance technologies. The cost estimation is presented in tabular form for per learning kit provided to the students for Hands on experiments. Some Popular In addition, some Open source tools for experimenting with IoT Technology are described. Students can enrich their knowledge by doing lots of experiments with these freely available software's and this low cost hardware in labs or learning kits provided to them.

주요 혈관 근처의 췌장 또는 췌장 주위 병변에 대한 초음파 유도하 경피적 중심 바늘 생검의 안전성과 효율성 (Safety and Efficacy of Ultrasound-Guided Percutaneous Core Needle Biopsy of Pancreatic and Peripancreatic Lesions Adjacent to Critical Vessels)

  • 정선화;강현지;이효정;김진실;이정경
    • 대한영상의학회지
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    • 제82권5호
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    • pp.1207-1217
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    • 2021
  • 목적 췌장 및 췌장 주위의 주요 혈관에 인접한 병변에 대하여 초음파 유도하 경피적 중심 바늘 생검(ultrasound-guided percutaneous core needle biopsy; 이하 USPCB)의 안전성과 효능을 평가하였다. 대상과 방법 10년 동안 췌장(n = 98), 간문맥 근처 췌장 주위(n = 34), 또는 췌장 갈고리돌기 부위와 십이지장 제3부분과 인접한 대동맥주위(n = 30) 병변에 대하여 USPCB를 시행받은 162명의 환자의 검사 결과를 수집하였다. 초음파 유도하18게이지 바늘을 가진 자동 생검 총을 사용하였고, USPCB 결과는 수술 결과 또는 추적 관찰 영상과 비교하였다. USPCB의 진단 정확도 및 주요 합병증 비율을 계산했으며, 성공적인 생검의 예측을 위한 요인이 무엇인지 단변량 및 다변량 분석을 사용하여 평가하였다. 결과 USPCB에서 조직 병리학 진단은 149명(92%) 환자에서 일치했다. 주요 합병증은 장간막 혈종 4건과 십이지장 벽내혈종 1건이 발생했다(3%). 성공적인 생검을 위한 요인으로는 위 또는 장관을 통과하는 경로보다는 경장간막 경로를 이용할수록, 초음파상 표적 및 생검 경로가 잘 보일수록 등이 포함되었다. 또한 결과적으로 생검에 성공한 경우 생검 횟수가 더 적었다. 결론 USPCB는 주요 혈관에 인접한 췌장 및 간문맥 근처 췌장 주위 병변 또는 췌장 갈고리돌기 부위나 십이지장 제3부분과 인접한 대동맥 주위 병변의 조직학적 진단을 위한 높은 정확도 및 낮은 합병증 비율을 나타냈다.

지구과학 예비교사들의 컴퓨팅 사고에 대한 인식 탐색 (Exploring Pre-Service Earth Science Teachers' Understandings of Computational Thinking)

  • 박영신;박기락
    • 한국지구과학회지
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    • 제45권3호
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    • pp.260-276
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    • 2024
  • 이 연구의 목적은 공학기반 파력발전소 주제의 STEAM 수업을 통해서 지구과학전공 예비교사들의 컴퓨팅 사고에 대한 인식형성 및 개선이 있는지를 탐색하는 것이다. STEAM 수업은 가장 효율적인 파력발전소 모형을 제작해보는 내용으로 구성되었다. 컴퓨팅 사고 실천 인식을 알아보는 설문지는 연구자가 기존의 연구를 중심으로 설문 문항을 개발하여 15명의 예비교사들에게 투입하였다. STEAM 수업은 파도를 이용해서 터빈이 돌아가는 과학적 원리 이해를 바탕으로 모둠별로 효율적인 파력발전소 모형을 개발하도록 하였으며 수업 중에 문제를 인식하고(문제해결), 코딩작업을 해서(코딩 및 프로그래밍) 3D 프린터로 파력발전소를 제작하였으며(모델 설계 및 구축), 제작된 산출물을 평가하여 오류를 수정하는(문제 오류 수정) 동안에 '논리적 사고'를 통한 높은 수준의 컴퓨팅 사고 실천 인식이 파악되었다(14개 중에 앞의 5개 실천은 평균 5점). 하지만 용어에 대한 정확한 정의를 알지 못하고 실시한 수업에서 '추상화'. '문제분해', 및 '빅 데이터 활용'에 대한 인식은 오히려 수업 후의 인식은 더 낮아졌다(3개의 실천). STEAM 수업 후에는 컴퓨팅 사고 실천은 '온라인 게임하기'는 아니라는 것에 인식개선이 있었지만(4.06→0.86; 역문항) 아직도 컴퓨터를 이용해서 해야 하는 컴퓨팅 사고 실천으로 인식하고 있어 개선되지 않음이 확인되었다(컴퓨터처럼 생각하기, 컴퓨터를 사용하여 통계하기). 문제 인식에 해당하는 '문제해결'(3.73→4.33), '패턴 인식'(3.53→3.66), 그리고 '최상의 도구 선택'(4.26→4.66)의 3개 실천은 인식이 약하게 개선되었다. 컴퓨팅 사고 실천과 같은 역량 함양을 위해서는 실습위주의 교육양성과정이 개설되어야 하며, 특히 본 연구에서는 다른 주제의 추가적인 STEAM 수업을 했다면 개선이 일어나지 않거나 약하게 인식되었던 컴퓨팅 사고 실천에 대해서는 확실한 개선이 있을 수 있다는 결론을 내릴 수 있다. 다회적인 상황학습의 교육실습 교육과정이 개설되어야 한다.

운동훈련(運動訓練)에 대(對)한 심폐기능(心肺機能)의 적응(適應)에 관(關)한 연구(硏究) (Cardio-pulmonary Adaptation to Physical Training)

  • 조강하
    • The Korean Journal of Physiology
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    • 제1권1호
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    • pp.103-120
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    • 1967
  • As pointed out by many previous investigators, the cardio-pulmonary system of well trained athletes is so adapted that they can perform a given physical exercise more efficiently as compared to non-trained persons. However, the time course of the development of these cardio-pulmonary adaptations has not been extensively studied in the past. Although the development of these training effects is undoubtedly related to the magnitude of an exercise load which is repeatedly given, it would be practical if one could maintain a good physical fitness with a minimal daily exercise. Hence, the present investigation was undertaken to study the time course of the development of cardio-pulmonary adaptations while a group of non-athletes was subjected to a daily 6 to 10 minutes running exercise for a period of 4 weeks. Six healthy male medical students (22 to 24 years old) were randomly selected as experimental subjects, and were equally divided into two groups (A and B). Both groups were subjected to the same daily running exercise (approximately 1,000 kg-m). 6 days a week for 4 weeks, but the rate of exercise was such that the group A ran on treadmill with 8.6% grade for 10 min daily at a speed of 127 m/min while the group B ran for 6 min at a speed of 200 m/min. In order to assess the effects of these physical trainings on the cardio-pulmonary system, the minute volume, the $O_2$ consumption, the $CO_2$ output and the heart rate were determined weekly while the subject was engaged in a given running exercise on treadmill (8.6% grade and 127 m/min) for a period of 5 min. In addition, the arterial blood pressure, the cardiac output, the acid-base state of arterial blood and the gas composition of arterial blood were also determined every other week in 4 subjects (2 from each group) while they were engaged in exercise on a bicycle ergometer at a rate of approximately 900 kg m/min until exhaustion. The maximal work capacity was also determined by asking the subject to engage in exercise on treadmill and ergometer until exhaustion. For the measurement of minute volume, the expired gas was collected in a Douglas bag. The $O_2$ consumption and the $CO_2$ output were subsequently computed by analysing the expired gas with a Scholander micro gas analyzer. The heart rate was calculated from the R-R interval of ECG tracings recorded by an Offner RS Dynograph. A 19 gauge Cournand needle was inserted into a brachial artery, through which arterial blood samples were taken. A Statham $P_{23}AA$ pressure transducer and a PR-7 Research Recorder were used for recording instantaneous arterial pressure. The cardiac output was measured by indicator (Cardiogreen) dilution method. The results may be summarized as follows: (1) The maximal running time on treadmill increased linearly during the 4 week training period at the end of which it increased by 2.8 to 4.6 times. In general, an increase in the maximal running time was greater when the speed was fixed at a level at which the subject was trained. The mammal exercise time on bicycle ergometer also increased linearly during the training period. (2) In carrying out a given running exercise on treadmill (8.6%grade, 127 m/min), the following changes in cardio·pulmonary functions were observed during the training period: (a) The minute volume as well as the $O_2$ consumption during steady state exercise tended to decrease progressively and showed significant reductions after 3 weeks of training. (b) The $CO_2$ production during steady state exercise showed a significant reduction within 1 week of training. (c) The heart rate during steady state exercise tended to decrease progressively and showed a significant reduction after 2 weeks of training. The reduction of heart rate following a given exercise tended to become faster by training and showed a significant change after 3 weeks. Although the resting heart rate also tended to decrease by training, no significant change was observed. (3) In rallying out a given exercise (900 kg-m/min) on a bicycle ergometer, the following change in cardio-vascular functions were observed during the training period: (3) The systolic blood pressure during steady state exercise was not affected while the diastolic blood Pressure was significantly lowered after 4 weeks of training. The resting diastolic pressure was also significantly lowered by the end of 4 weeks. (b) The cardiac output and the stroke volume during steady state exercise increased maximally within 2 weeks of training. However, the resting cardiac output was not altered while the resting stroke volume tended to increase somewhat by training. (c) The total peripheral resistance during steady state exercise was greatly lowered within 2 weeks of training. The mean circulation time during exorcise was also considerably shortened while the left heart work output during exercise increased significantly within 2 weeks. However, these functions_at rest were not altered by training. (d) Although both pH, $P_{co2}\;and\;(HCO_3-)$ of arterial plasma decreased during exercise, the magnitude of reductions became less by training. On the other hand, the $O_2$ content of arterial blood decreased during exercise before training while it tended to increase slightly after training. There was no significant alteration in these values at rest. These results indicate that cardio-pulmonary adaptations to physical training can be acquired by subjecting non-athletes to brief daily exercise routine for certain period of time. Although the time of appearance of various adaptive phenomena is not identical, it may be stated that one has to engage in daily exercise routine for at least 2 weeks for the development of significant adaptive changes.

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간호원의 환자교육 활동에 관한 연구 (Study of Patient Teaching in The Clinical Area)

  • 강규숙
    • 대한간호학회지
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    • 제2권1호
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    • pp.3-33
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    • 1971
  • Nursing of today has as one of its objectives the solving of problems related to human needs arising from the demands of a rapidly changing society. This nursing objective, I believe, can he attained by the appropriate application of scientific principles in the giving of comprehensive nursing care. Comprehensive nursing care may be defined as nursing care which meets all of the patient's needs. the needs of patients are said to fall into five broad categories: physical needs, psychological needs, environmental needs, socio-economic needs, and teaching needs. Most people who become ill have adjustment problems related to their new situation. Because patient teaching is one of the most important functions of professional nursing, the success of this teaching may be used as a gauge for evaluating comprehensive nursing care. This represents a challenge foe the future. A questionnaire consisting of 67 items was distributed to 200 professional nurses working ill direct patient care at Yonsei University Medical Center in Seoul, Korea. 160 (80,0%) nurses of the total sample returned completed questionnaires 81 (50.6%) nurses were graduates of 3 fear diploma courser 79 (49.4%) nurses were graduates of 4 year collegiate nursing schools in Korea 141 (88,1%) nurses had under 5 years of clinical experience in a medical center, while 19 (11.9%) nurses had more than 5years of clinical experience. Three hypotheses were tested: 1. “Nurses had high levels of concept and knowledge toward patient teaching”-This was demonstrated by the use of a statistical method, the mean average. 2. “Nurses graduating from collegiate programs and diploma school programs of nursing show differences in concepts and knowledge toward patient teaching”-This was demonstrated by a statistical method, the mean average, although the results showed little difference between the two groups. 3. “Nurses having different amounts of clinical experience showed differences in concepts and knowledge toward patient teaching”-This was demonstrated by the use of a statistical method, the mean average. 2. “Nurses graduating from collegiate programs and diploma school programs of nursing show differences in concepts and knowledge toward patient teaching”-This was demonstrated by a statistical method, the mean average, although the results showed little difference between the two groups. 3. “Nurses having different amounts of clinical experience showed differences in concepts and knowledge toward patient teaching”-This was demonstrated by the use of the T-test. Conclusions of this study are as follow: Before attempting the explanation, of the results, the questionnaire will he explained. The questionnaire contained 67 questions divided into 9 sections. These sections were: concept, content, time, prior preparation, method, purpose, condition, evaluation, and recommendations for patient teaching. 1. The nurse's concept of patient teaching: Most of the nurses had high levels of concepts and knowledge toward patient teaching. Though nursing service was task-centered at the turn of the century, the emphasis today is put on patient-centered nursing. But we find some of the nurses (39.4%) still are task-centered. After, patient teaching, only a few of the nurses (14.4%) checked this as “normal teaching.”It seems therefore that patient teaching is often done unconsciously. Accordingly it would he desirable to have correct concepts and knowledge of teaching taught in schools of nursing. 2. Contents of patient teaching: Most nurses (97.5%) had good information about content of patient teaching. They teach their patients during admission about their diseases, tests, treatments, and before discharge give nurses instruction about simple nursing care, personal hygiene, special diets, rest and sleep, elimination etc. 3. Time of patient teaching: Teaching can be accomplished even if there is no time set aside specifically for it. -a large part of the nurse's teaching can be done while she is giving nursing care. If she believes she has to wait for time free from other activities, she may miss many teaching opportunities. But generally proper time for patient teaching is in the midmorning or midafternoon since one and a half or two hours required. Nurses meet their patients in all stages of health: often tile patient is in a condition in which learning is impossible-pain, mental confusion, debilitation, loss of sensory perception, fear and anxiety-any of these conditions may preclude the possibility of successful teaching. 4. Prior preparation for patient teaching: The teaching aids, nurses use are charts (53.1%), periodicals (23.8%), and books (7.0%) Some of the respondents (28.1%) reported that they had had good preparation for the teaching which they were doing, others (27.5%) reported adequate preparation, and others (43.8%) reported that their preparation for teaching was inadequate. If nurses have advance preparation for normal teaching and are aware of their objectives in teaching patients, they can do effective teaching. 5. Method of patient teaching: The methods of individual patient teaching, the nurses in this study used, were conversation (55.6%) and individual discussion (19.2%) . And the methods of group patient teaching they used were demonstration (42.3%) and lecture (26.2%) They should also he prepared to use pamphlet and simple audio-visual aids for their teaching. 6. Purposes of patient teaching: The purposes of patient teaching is to help the patient recover completely, but the majority of the respondents (40.6%) don't know this. So it is necessary for them to understand correctly the purpose of patient teaching and nursing care. 7. Condition of patient teaching: The majority of respondents (75.0%) reported there were some troubles in teaching uncooperative patients. It would seem that the nurse's leaching would be improved if, in her preparation, she was given a better understanding of the patient and communication skills. The majority of respondents in the total group, felt teaching is their responsibility and they should teach their patient's family as well as the patient. The place for teaching is most often at the patient's bedside (95.6%) but the conference room (3.1%) is also used. It is important that privacy be provided in learning situations with involve personal matters. 8. Evaluation of patient teaching: The majority of respondents (76.3%,) felt leaching is a highly systematic and organized function requiring special preparation in a college or university, they have the idea that teaching is a continuous and ever-present activity of all people throughout their lives. The suggestion mentioned the most frequently for improving preparation was a course in patient teaching included in the basic nursing program. 9. Recommendations: 1) It is recommended, that in clinical nursing, patient teaching be emphasized. 2) It is recommended, that insertive education the concepts and purposes of patient teaching he renewed for all nurses. In addition to this new knowledge, methods and materials which can be applied to patient teaching should be given also. 3) It is recommended, in group patient teaching, we try to embark on team teaching.

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스트레인 게이지를 이용한 수종의 복합레진의 중합수축 및 수축응력의 비교 (COMPARISON OF POLYMERIZATION SHRINKAGE AND STRAIN STRESS OF SEVERAL COMPOSITE RESINS USING STRAIN GUAGE)

  • 김영광;유승훈;김종수
    • 대한소아치과학회지
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    • 제31권3호
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    • pp.516-526
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    • 2004
  • 심미적인 재료로 널리 사용되고 있는 복합레진은 중합과정에서 발생하는 수축으로 인해 여러 임상적 문제를 유발할 수 있다. 중합수축을 최소화하기 위한 방법의 하나로 복합레진의 성분을 변화시키는 방법이 연구되어 왔다. 본 연구의 목적은 기질조성의 변화를 통한 중합수축의 감소를 위해 최근 개발된 복합레진과 나노필러를 이용한 복합레진을 대상으로 중합과정에서 발생하는 수축량 및 수축응력을 측정하고 각 재료의 압축강도와 미세경도를 측정한 다음 그 결과들을 기존의 복합레진과 종합적으로 비교하여 평가해 보고자 하는 것이었다. 시편은 각 군당 20개씩 준비하였으며 실험에 사용된 복합레진으로는 Bis-GMA 기질에 TEGDMA와 UDMA를 혼합한 $Denfil^{TM}$(Vericom, 한국) $0.4-0.7{\mu}m$의 필러를 기준으로 나노필러를 첨가한 $Charmfil^{(R)}$(Dentkist, 한국), 기질의 TEGDMA의 상당부분을 UDMA와 Bis-EMA(6)로 대체한 $Filtek^{TM}$ Z250(3M-ESPE, USA), 그리고 나노필러만을 이용한 $Filtek^{TM}$ Supreme(3M-ESPE, USA)를 선정하였으며, 광중합기인 Curing Light 2500(3M, USA)를 이용하여 각각 40초간 광조사하였다. 광조사 후 1초 간격으로 10분간 수축응력과 선 수축률을 스트레인 게이지를 이용하여 측정한 다음 그래프로 분석하였고, 중합 1분 후와 10분 후의 수축응력과 선 수축률을 통계분석하였다. 또한 만능시험기와 미세경도기를 이용하여 중합 24시간 후 각 군의 압축강도와 미세경도를 측정하여 통계분석하였다. 수축응력 양상을 관찰해 본 결과 각 군에서 모두 중합 초기에 일시적인 재료의 팽창을 나타내었고, 그 후 수축응력이 약 1분간 급격히 증가한 다음 서서히 증가속도가 감소하는 양상을 보였다. 1분 후에서는 각 군간에 통계학적 유의성은 없었다. 10분 후에서는 IV군과 II군간에 유의한 차이가 존재하였다(p<.05). 1분간 측정한 회귀분석에서는 III군의 기울기가 가장 적었고, II군 I군, IV군의 순이었다. 중합수축률 측정 실험에서는 중합 초기의 일시적 인 팽창과 약 1분간의 급격한 수축 증가를 나타내었고 그 후 서서히 증가속도가 감소하는 양상을 보였다. 1분 후에서는 IV군과 III군간에 유의한 차이가 있었다(p<.05). 10분후에서는 IV군이 I군과 III군에서 유의 한 차이가 있었으며 II군과 III군간에도 유의한 차이가 있었다(p<.05). 1분간 측정한 회귀분석에서는 II군의 기울기가 가장 적었으며, IV군, III군, I군의 순이었다. 압축강도 실험에서는 III군, II군, IV군, I군의 순으로 높게 나타났으며, III군이 IV군과 I군에 유의한 차이가 있었다(p<.05). 미세경도 실험에서는 모든 군에서 상면에 비해 하면의 미세경도가 통계학적으로 유의차 있게 낮은 것으로 나타났다(p<.05). 이상의 결과를 종합하여 볼 때, hybrid 필러를 이용한 레진에서 상대적으로 낮은 수축률과 우수한 물성을 보였으며, 나노필러를 사용한 복합레진의 경우, 기존의 hybrid 필러를 이용한 레진에 비하여 수축응력을 감소시키지는 못하였다. 나노필러를 이용한 복합레진은 개발의 초기단계이며, 물성의 증가를 위한 연구가 필요할 것으로 사료된다.

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공해(公害)에 관(關)한 조사연구(調査硏究) 제일편(第一編) : 서울, 부산(釜山), 대구(大邱) 지역(地域)의 대기오염(大氣汚染) 및 소음(騷音)에 관(關)한 비교조사(比較調査) 연구(硏究) (A Study on Public Nuisance in Seoul, Pusan and Daegu Cities Part I. Survey on Air Pollution and Noise Level)

  • 차철환;신영수;이영일;조광수;주종유;김교성;최덕일
    • Journal of Preventive Medicine and Public Health
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    • 제4권1호
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    • pp.41-64
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    • 1971
  • During the period from July 1st to the end of November 1970, a survey on air pollution and noise level was made in Seoul, Pusan and Taegu, the three largest cities in Korea. Each city was divided into 4-6 areas; the industrial area, the semi-industrial area, the commercial area, the residential area, the park area and the downtown area. Thirty eight sites were selected from each area. A. Method of Measurement : Dustfall was measured by the Deposit Gauge Method, sulfur oxides by $PbO_2$ cylinder method, suspended particles by the Digital Dust Indicator, Sulfur dioxide ($SO_2$) and Carbon Monoxide (CO) by the MSA & Kitakawa Detector and the noise levels by Rion Sound Survey meter. B. Results: 1. The mean value of dustfall in 3 cities was $30.42ton/km^2/month$, ranging from 8.69 to 95.44. 2. The mean values of dustfall by city were $33.17ton/km^2/month$ in Seoul, 32.11 in Pusan and 25.97 in Taegu. 3. The mean values of dustfall showed a trend of decreasing order of semi-industrial area, downtown area, industrial area, commercial area, residential area, and park area. 4. The mean value of dustfall in Seoul by area were $52.32ton/km^2/month$ in downtown, 50.54 in semi-industrial area, 40.37 in industrial area, 24,19 in commercial area, 16.25 in park area and 15.39 in residential area in order of concentration. 5. The mean values of dustfall in Pusan by area were $48.27ton/km^2/month$ in semi-industrial area, 36.68 in industrial area 25.31 in commercial area, and 18.19 in residential area. 6. The mean values of dustfall in Taegu by area were $36.46ton/km^2/month$ in downtown area, 33.52 in industrial area, 20.37 in commercial area and 13.55 in residential area. 7. The mean values of sulfur oxides in 3 cities were $1.52mg\;SO_3/day/100cm^2\;PbO_2$, ranging from 0.32 to 4.72. 8. The mean values of sulfur oxides by city were $1.89mg\;SO_3/day/100cm^2\;PbO_2$ in Pusan, 1.64 in Seoul and 1.21 in Taegu. 9. The mean values of sulfur oxides by area in 3 cities were $2.16mg\;SO_3/day/100cm^2\;PbO_2$ in industrial area, 1.69 in semi-industrial area, 1.50 in commercial area, 1.48 in downtown area, 1.32 in residential area and 0.94 in the park area, respectively. 10. The monthly mean values of sulfur oxides contents showed a steady increase from July reaching a peak in November. 11. The mean values of suspended particles was $2.89mg/m^3$, ranging from 1.15 to 5.27. 12. The mean values of suspended particles by city were $3.14mg/m^3$ in Seoul, 2.79 in Taegu and 2.25 in Pusan. 13. The mean values of noise level in 3 cities was 71.3 phon, ranging from 49 to 99 phon. 14. The mean values of noise level by city were 73 phon in Seoul, 72 in Pusan, and 69 in Taegu in that order. 15. The mean values of noise level by area in 3 cities showed a decrease in the order of the downtown area, commercial area, industrial area and semi-industrial area, park area and residential area. 16. The comparison of the noise levels by area in 3 cities indicated that the highest level was detected in the downtown area in Seoul and Taegu and in the industrial area in Pusan. 17. The daily average concentration of sulfur dioxides ($SO_2$) in 3 cities was 0.081 ppm, ranging from 0.004 to 0.196. 18. The daily average concentrations of sulfur dioxides by city were 0.092 ppm in Seoul, 0.089 in Pusan and 0.062 in Taegu in that order. 19. The weekly average concentration of carbon monoxides(CO) was 27.59 ppm. 20. The daily average concentrations of carbon monoxides by city were 33.37 ppm. in Seoul, 25.76 in Pusan and 23.65 in Taegu in that order. 21. The concentration of $SO_2$ and CO reaches a peak from 6 p. m. to 8 p. m. 22. About 3 times probably the daily average concentration of CO could be detected in the downtown area probably due to heavy traffic emission in comparison with that in the industial area. 23. As for daily variation of the concentration of $SO_2$ and CO it was found that the concentration maintains relatively higher value during weekdays in the industrial area and on the first part of the week in the downtown area.

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경주 옥산구곡(玉山九曲)의 위치비정과 경관해석 연구 - 이정엄의 「옥산구곡가」를 중심으로 - (A Study on the Consideration of the Locations of Gyeongju Oksan Gugok and Landscape Interpretation - Focusing on the Arbor of Lee, Jung-Eom's "Oksan Gugok" -)

  • 펑홍쉬;강태호
    • 한국전통조경학회지
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    • 제36권3호
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    • pp.26-36
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    • 2018
  • 본 논문은 경주 옥산구곡의 위치와 경관 해석에 대한 연구이다. 옥산구곡은 회재(晦齋) 이언적(李彦迪)을 향사하는 옥산서원 앞을 흐르는 자계천(紫溪川, 자옥천(紫玉山)) 즉, 옥산천(玉山川)에 설정(設定)된 구곡으로 본 연구에서는 옥산구곡을 대상으로 문헌조사와 디지털 기기 분석을 통해 현장 실측분석을 수행하여 옥산구곡의 위치 및 설정상황을 확인하였다. 특히 Trimble Juno SB GPS로 측정한 구곡의 경위도와 같이 Google Earth Pro 및 지리정보원이 공개한 옥산구곡의 수치지형도를 이용해서 옥산구곡의 정확한 위치를 확정하였다. 문헌연구 및 현장조사를 통하여, 옥산구곡의 위치 비정 및 경관 해석 결과는 다음과 같다. 첫째, 퇴계 이황의 9세손 이야순(李野淳)은 이언적 사후 270년인 1823년 봄에 옥산서원을 방문하였다. 이때 이야순의 제안으로 이언적의 후손 이정엄(李鼎儼), 이정기(李鼎基), 이정병(李鼎秉) 등과 여러 선비들이 함께 옥산구곡을 처음 설정하고 함께 "옥산구곡가"를 창작했다. 이정엄의 "옥산동행기"는 옥산구곡의 설정할 때의 상황을 알려주는 결정적 자료이다. 둘째, 대부분의 구곡원림은 일반적인 시인묵객이 경영한 원림이 아니고 정통 성리학자들이 경영한 원림이다. 이언적과 이황의 후손이 "옥산구곡가"를 함께 창작한 것은 이언적이나 이황이 정통 주자학을 계승했다는 점에 대한 후손들의 자긍심의 한 표현이다. 셋째, 이정엄의 "옥산동행기"에는 "옥산구곡가"의 설곡 과정과 구곡가 창작 과정은 매우 구체적으로 기록되어 있는데, 구곡가의 설곡과정과 그때의 상황이 이처럼 구체적으로 드러난 것은 희귀한 사례라고 할 것이다. 넷째, 기존에 알려진 옥산구곡 제8곡과 제9곡의 위치를 새롭게 비정하였다. 확정된 제8곡 탁영대의 위치정보는 북위 $36^{\circ}01^{\prime}08.60^{{\prime}{\prime}}$,동경 $129^{\circ}09^{\prime}31.20^{{\prime}{\prime}}$이다. 9곡 사자암은 고문헌을 참고하여, 동서의 두 계곡이 모이는 아래쪽 바위로 비정하였다. 그 위치는 북위 $36^{\circ}01^{\prime}19.79^{{\prime}{\prime}}$, 동경 $129^{\circ}09^{\prime}30.26^{{\prime}{\prime}}$이다. 다섯째, 이정엄의 "옥산구곡가"에 나타난 경관요소와 경관현상은 형태요소, 의미요소, 풍토요소로 나누었다. 그 결과 이정엄의 조영관은 산수를 이상향으로 생각하는 점과 자연에 한가하게 노니는 심정과 아울러 무상감을 확인할 수 있었다. 여섯째, 경관요소와 경관현상들의 출현빈도를 살펴본 결과, 이정엄의 구곡가에서'물'과 '산'은 구곡원림을 조영하는 절대적인 요소였다. 따라서 이 구곡가에는 신선사상(神仙思想) 및 은거사상(隱居思想)이 내재되어 있는 것은 물론 산수간의 조화를 통해 자연과 하나가 되는 물아일체의 사상과 성리학적인 수행관을 살필 수 있었다.