• 대한지구과학교육학회지
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• 제7권2호
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• pp.159-168
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• 2014

본 연구는 90명의 고등학생들(성취도 상 중 하 수준의 각 30명)을 대상으로 GAP 프로그램의 일환으로 개발된 10개의 문항으로 지구과학자에 대한 인식을 분석하였다. 고등학생들은 지구과학 교과에 대한 긍정적인 인식을 갖고 있으나, 직업인으로서 지구과학자에 대한 이해가 매우 부족하며, 자신의 진로로 연계하여 인식하지 못하고 있는 실정이다. 성취 수준이 낮은 학생들의 지구과학 학습의 실패는 지구과학자에 대한 부정적인 인식과 미래 진로로의 비연계로 이어졌다. 학교교육 현장에서부터 학생들이 지구과학자를 접할 수 있는 기회를 제공하고 진로교육 프로그램을 통해 직업으로 연계시키려는 노력이 절실하게 필요하다.

• 동력기계공학회지
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• 제18권4호
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• pp.43-51
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• 2014

In this paper, transient temperature and vibration characteristics of a brushless DC (BLD(c) motor are studied for external load (165W~495W) and rotational speed (2000 rpm~4000 rpm). For experiment, a simple measurement system is developed to allow a change in load and speed for measuring transient temperature and vibration simultaneously. Temperature and vibration were also measured under the conditions of natural convection and forced convection. Vibrations in the directions of x-axis (#Ch1), y -axis (#Ch2) and z -axis (#Ch3) were obtained by three accelerometers and temperature was obtained by a thermo-couple with respect to time until the motor is steady. Experimental results show that the amplitude of vibration is higher in the order of z-axis (#Ch3), x -axis (#Ch1) and y-axis (#Ch2) and the amplitude of vibration at the forced convection conditions is 10.6% to 17.8% lower than that of vibration at the natural convection. However, the ratio of the vibration value is similar on average regardless of external convection condition.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.270-279
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• 2014

Microbial community shifts, associated with performance data, were investigated in an anaerobic batch digester treating high-solid food waste under mesophilic conditions using, a combination of molecular techniques and chemical analysis methods. The batch process was successfully operated with an organic removal efficiency of 44.5% associated with a biogas yield of 0.82 L/g $VS_{removal}$. Microbial community structures were examined by denaturing gel gradient electrophoresis. Clostridium and Symbiobacterium organisms were suggested to be mainly responsible for the organic matter catabolism in hydrolysis and acidogenesis reactions. The dynamics of archaeal and methanogenic populations were monitored using real-time PCR targeting 16S rRNA genes. Methanosarcina was the predominant methanogen, suggesting that the methanogenesis took place mainly via an aceticlastic pathway. Hydrogenotrophic methanogens were also supported in high-solid anaerobic digestion of food waste through syntrophism with syntrophic bacterium. Microbial community shifts showed good agreement with the performance parameters in anaerobic digestion, implying the possibility of diagnosing a high-solid anaerobic digestion process by monitoring microbial community shifts. On the other hand, the batch results could be relevant to the start-up period of a continuous system and could also provide useful information to set up a continuous operation.

• 환경위생공학
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• 제22권2호
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• pp.53-60
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• 2007

A pilot study was conducted in order to investigate the concentration of formaldehyde at elementary school, middle school, the high school (108 classrooms) located in Chungchong-namdo during February - September, 2006. Also, divide by (45 classroom) General Classroom and (63 classrooms) Stateroom. The average concentrations of formaldehyde(HCHO) in the general classroom was high by $22.87\;{\pm}\;20.61\;{\mu}g/m^3$ elementary school, $22.08\;{\pm}\;12.70\;{\mu}g/m^3$ high school, $13.58\;{\pm}\;6.60\;{\mu}g/m^3$ middle school. The average concentrations of formaldehyde(HCHO) in the Stateroom was high by $27.58\;{\pm}\;30.5{\mu}g/m^3$ elementary school, $22.03\;{\pm}\;19.12\;{\mu}g/m^3\;22.87\;{\pm}\;20.61\;{\mu}g/m^3$ middle school, $24.92\;{\pm}\;28.15\;{\mu}g/m^3$ high school. There was correlation between formaldehyde concentrations and temperature, humidity in general classroom (P<0.05).

• Nutrition Research and Practice
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• 제7권1호
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• pp.59-65
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• 2013

Excessive sodium intake leading to hypertension, stroke, and stomach cancer is mainly caused by excess use of salt in cooking. This study was performed to estimate the salt content in school meals and to compare differences in perceptions related to sodium intake between students and staffs working for school meal service. We collected 382 dishes for food from 24 schools (9 elementary, 7 middle, 8 high schools) in Gyeonggi-do and salt content was calculated from salinity and weight of individual food. The average salt content from elementary, middle, and high school meals were 2.44 g, 3.96 g, and 5.87 g, respectively. The amount of salt provided from the school lunch alone was over 80% of the recommended daily salt intake by WHO. Noodles, stews, sauces, and soups were major sources of salt intake at dish group level, while the most salty dishes were sauces, kimchies, and stir-fried foods. Dietary knowledge and attitude related to sodium intake and consumption frequency of the salty dishes were surveyed with questionnaire in 798 students and 256 staffs working for school meal service. Compared with the staffs, the students perceived school meals salty and the proportions of students who thought school meals were salty increased with going up from elementary to high schools (P < 0.001). Among the students, middle and high school students showed significant propensity for the preference to one-dish meal, processed foods, eating much broth and dipping sauce or seasoning compared with the elementary students, although they had higher nutrition knowledge scores. These results proposed that monitoring salt content of school meals and consideration on the contents and education methods in school are needed to lower sodium intake.

• 한국식생활문화학회지
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• 제25권4호
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• pp.400-409
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• 2010

This study investigated the food and dietary educational content in primary, middle and high school textbooks in order to provide fundamental data for the development of educational programs on Korean traditional food culture. The research objects consisted of 51 kinds of textbooks (15 kinds of primary school textbooks, 29 kinds of middle school home economics textbooks and 7 kinds of high school home economics textbooks), and the contents related to food and dietary education were counted and analyzed. The content analysis was performed using two categories: application method and subject matter. Application method included texts, cases, visual aids (pictures, photos, illustrations, chart, etc.) and activities, whereas subject matter consisted of seven types (well balanced nutrition and health, understanding of food and nutrition, cooking principles, cooking lessons, traditional foods and culture, others). The results of the application method in primary school textbooks show that visual aids were the most common in all six grades. For the subject matter, 'understanding of food and nutrition' was most abundant in primary school textbooks while 'well balanced nutrition and health' accounted for a large part of the contents in middle school textbooks. However, the contents regarding traditional foods and culture were insufficient in primary and middle school textbooks. These results suggest that educational contents on traditional foods and culture should be added to primary and middle school textbooks and covered in various subjects. Furthermore, high school 'home economics' contents need to emphasize comprehensive food and dietary education and adjust to 'science & technology for life'.

• 천문학회보
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• 제41권1호
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• pp.52.1-52.1
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• 2016

We introduce the characteristics and performance of the 0.25m telescope at Mangpo high school Unmanned Robotic Observatory (MURO) which was established in Yangpyeong-gun, Gyeongi-do, KOREA in 2015 January. MURO system included Astrohaven 2.1m non-rotation fiberglass clamshell dome, Paramount MEII mount, Takahashi CCA 0.25m wide field telescope, FLI PL 16803 4K CCD with 7-positions filter wheel system, all sky camera and point grey wide field camera, IR 4 chanel heat sensor camera for security, DAVIS realtime weather cast, and power controled by ARS system. All control softwares are from off-the-shelf products based on Windows 7 OS to be easily operated and maintained. We expect to perform variety of science programs ranging from supernovae follow-up observation to narrow band imaging survey as well as science class activities at Mangpo high school.

• 과학교육연구지
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• 제35권2호
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• pp.119-126
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• 2011

이 연구의 목적은 고등학교 화학 I 교과에서 small-scale chemistry (SSC)를 활용한 실험수업이 고등학생들의 학업성취도와 과학적 태도 및 과학에 관련된 태도에 미치는 영향을 알아보는 것이다. 연구를 위하여 고등학교 2학년 2개 학급을 실험집단과 통제집단으로 나누어 실험집단에는 SSC를 활용한 실험수업을, 통제집단에는 교과서에 제시된 전통적인 실험수업을 실시하였다. 연구 결과, SSC를 활용한 실험수업은 전통적인 실험수업에 비해 학업성취도를 향상시키는 효과가 있었으며, 과학적 태도에서는 자진성과 끈기성 및 협동성을, 과학에 관련된 태도에서는 과학의 사회적 의미와 과학교과에 대한 태도 및 과학에 대한 태도를 향상시키는 효과가 있었다. 그러므로 교육 현장에서는 SSC를 활용한 실험수업을 고등학교 화학교과에 적극적으로 활용할 필요가 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.75-79
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• 2001

This paper presents a novel version of an active voltage clamped ZVS-PWM high frequency inverter using IGBTs for electromagnetic induction eddy current-based rolling drum heating in new generation copy and printing machines in consumer business use. The operating principle of this inverter circuit and unique features are described herein. Its constant frequency duty cycle (asymmetrical PWM) controlled voltage source quasi-resonant soft switching high frequency inverter employing IGBTs is proposed, which is capable of achieving stable and efficient zero voltage soft switching commutation over a widely specified power regulation range from full power to low power. The operating performances in a steady state of this inverter is discussed and evaluated on basis of simulation and experimental results as an induction heated roller in new generation copy machine.

• 수산해양교육연구
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• 제15권2호
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• pp.154-165
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• 2003

Fisheries and shipping industry as national basic industry need continuous growth and basic human resource development for international competition. This study was carried out through investigating of the related literature and reports. The purpose of study for developing direction and subject matter of curriculum in the fisheries marine science high school was as follows. Recently, reforms of vocational high school will expand professionalization and specialization. Therefore systematic curriculum of basic knowledge, basic skill and technical is required more and more in field work of fishery and merchant marine. The other important factors of curriculum improvement were cooperative role between school and local industry, adaptation of basic ability, job analysis, various curriculum opening. Above all, teachers of fisheries and merchant marine high school require advanced consciousness and must participate in revising curriculum. And the textbook of fisheries and merchant marine high school is useful to improve the level of learning ability degree and must be written by the related teacher, and the textbook contents must be studied by the expert group under professors leading to advanced discipline and skill of field work.