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鄭玩鎬,車喜英 한국교원대학교 과학교육연구소 1994 청람과학교육연구논총 Vol.4 No.1
In this study, in order to find out high school students' misconceptions on genetics and evolution, a free-answer form of questionnaire, specially designed through analysis of high school biology curriculum, was developed and sent to one hundred and eight high school students in Seoul area. Their responses were collected and qualitatively analyzed. Main results of the study can be summarized as follows: 1. Some students misunderstood that aquired chracters are inherited. 2. Several students weren't instructed clearly about gene. For example, they responsed that genes are not material, composed of proteins, exist only in reproductive cells and are not in plant cells at all. 3. Some students confused chromosome with chlorophyll, dominant (in dorminant character) with excellent. They are caused by similar spells in Korean letter. 4. Half students misconceptualized that organisms evolve just when their environment changes for the worse. 5. Many students believed orthogenesis.
전완호(Wan-Ho Jeon),이덕주(Duck-Joo Lee) 한국유체기계학회 1998 유체기계 연구개발 발표회 논문집 Vol.- No.-
The objective of this study is to understand the generation mechanism of sound and to develop a prediction method for the unsteady flow field and the acoustic pressure field of a centrifugal fan. Lowson’s method is used to predict the acoustic pressure in a free field. A DVM(discrete vortex method) is used to model the centrifugal fan and to calculate the flow field. In order to compare the experimental data, a centrifugal fan and wedge introduced by Weidemann are used in the numerical calculation and the results are compared with the experimental data.
전완호(Wan-Ho Jeon),정필중(Phil-Joong Chung) 한국유체기계학회 2000 유체기계 연구개발 발표회 논문집 Vol.- No.-
Centrifugal fans are widely used and the noise generated by these machines causes one of the most serious problems. In general, the centrifugal fan noise is often dominated by tones at BPF(blade passage frequency) and its higher harmonics. This is a consequence of the strong interaction between the flow discharged from the impeller and the cutoff in the casing. However, only a few researches have been carried out on predicting the noise because of the difficulty in obtaining detailed information about the flow field and casing effects on noise radiation. The objective of this study is to develop a prediction method for the unsteady flow field and the acoustic pressure field of a centrifugal fan, and to calculate the effects of small vanes that are attached in original impeller - Splitter impeller. We assume that the impeller rotates with a constant angular velocity and the flow field around the impeller is incompressible and inviscid. So, a discrete vortex method (DVM) is used to model the centrifugal fan and to calculate the flow field. The force of each element on the blade is calculated by the unsteady Bernoulli equation. Lawson's method is used to predict the acoustic source. The splitter impeller changes the acoustic characteristics as well as performance. Two-splitter type impeller and splitter impeller which splitter locates in jet region are good for acoustic characteristics.
정완호,차희영,강석본 韓國生物敎育學會 1993 생물교육 Vol.21 No.1
The major purpose of this research was to identify high school students' misconceptions on physiology. Misconceptions of scientific concepts have been believed to be very persistent and difficult to be overcome through regular classroom activities. Therefore, to find out students' misconceptions and students' cognitive structure must be very important to design instructions as well as curriculum. In order to find out high school students' misconceptions on physiology, a open-ended form of questionnaire on the physiology of several biological areas was developed and sent to fifty-three high school students'. Their responses were collected and analyzed. From the analysis of all the Korean text books, it was found that some concepts were not described correctly. At tire same tinge, the terminology used in the text books was different from book to book. These incorrect. presentations and inconsistent use of terminology would have Been the source of students' misconceptions tin biology. Although the pattern of misconceptions that Korean students have in the area of photosynthesis was generally similar to one by foreign students, the misconceptions arose from biological terminology such as excretion and elimination were found to be specifically developed in Korean students who use Korean language. Although there a few special misconceptions in fragmentary, lower-level concepts, there were some misconceptions in comprehensive and fundamental higher-level concepts. This probably could have resulted from the fact that too many concepts were included in current Korean. textbooks and the entrance examination items were only knowledge level which need only be memorized line by line. Therefore, the content and concepts should be very carefully chosen in the text books.
조완호,정철호,장지호,이성현,박무균,서명환,한재준 대한청각학회 2019 Journal of Audiology & Otology Vol.23 No.2
Background and Objectives: Noise levels and room acoustic parameters at a tertiary referral hospital, Seoul National University Hospital (SNUH) in Korea, are investigated. Materials and Methods: Through a questionnaire, acoustically problematic rooms are identified. Noise levels in emergency rooms (ERs) and intensive care units (ICUs) are measured over about three days. Acoustically critical and problematic rooms in the otolaryngology department are measured including examination rooms, operating rooms, nurse stations, receptions, and patient rooms. Results: The A-weighted equivalent noise level, LAeq, ranges from 54 to 56 dBA, which is at least 10 dB lower than the noise levels of 65 to 73 dBA measured in American ERs. In an ICU, the noise level for the first night was 66 dBA, which came down to 56 dBA for the next day. The noise levels during three different ear surgeries vary from 57 to 62 dBA, depending on the use of surgical drills and suctions. The noise levels in a patient room is found to be 47 dBA, while the nurse stations and the receptions have high noise levels up to 64 dBA. The reverberation times in an operation room, examination room, and single patient room are found to be below 0.6 s. Conclusions: At SNUH, the nurse stations and receptions were found to be quite noisy. The ERs were quieter than in the previous studies. The measured reverberation times seemed low enough but some other nurse stations and examination rooms were not satisfactory according to the questionnaire.