• 한국환경교육학회지:환경교육
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• 제2권1호
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• pp.92-99
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• 1991

According to our secondary school curriculum for natural science and technical circles, there be used 353 of chemical reagents including 24 kinds of harmful and toxicant components. At present, most school are discharging their school laboratory waste water without any chemical and physical treatments. So as to solve the environmental problem for water pollution, this study tried to research a kind of adsorbant utilizing saw dust, wasted wood sources and designed the simple processing system using the adsorbent. This adsorbent was made by extracting lignin substances from raw saw dust under the solution of 0.5N-NaOH at the temperature of $100^{\circ}C$. Their metal removed rates was measured not only by processing of column and vessel. but also by comparing the standard solution and real waste water. The results were proved as more than 90(%) of the adsorptive efficiency on the average from Pb, Cd, Cu except Cr(VI)in case of the school experimental waste water soaked in vessels a long with 4g of the adsorbent for 24 hours. The new processing system enables to remove most harmful and toxicant metals by filtering, sedimenting and adsorbing at the low cost.

• 한국과학교육학회지
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• 제12권1호
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• pp.103-118
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• 1992

Quality control of science teachers seems to be one of the most important tasks to improve the quality of science education in Korea. The purposes of this study, as a survey, were to identify characteristics of good science teachers and to make an outline of preservice teacher education curriculum for cultivating the characteristics from inserivce secondary science teachers. A questionnaire was developed for this study and distributed to 176 inservice teachers. It had three parts: 1) characteristics of good science teachers, 2) weights of preservice curriclum areas, and 3) weights of college courses. The means and standard deviations of teachers' responses were calculated. To test the differences between teacher variables, t-tests were executed. The inservice teachers perceived that the junior-high school teacher's characteristics should be different from the senior-high school teacher's. Characteristics, such as enthusiasm toward teaching or students, subject knowledge, content selection and organizing skill, teaching techniques, and scientific worldview were ranked within top five of good science teacher's chracteristics. The teachers' perception about preservice curriculum were as follows: 1) present weight of liberal arts area should be reduced: 2) weight of content area for junior-high school teachers should be different from that for senior-high school teachers: 3) present weight of pedagogy area should be increased: 4) present weight of science education area should be increased: and 5) many courses in pedagogy and sciencd education areas need to be changed, Based on the data and disussion, a conceptual model for preservice teacher education curriculum was proposed.

• 한국과학교육학회지
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• 제22권3호
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• pp.478-489
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• 2002

이 연구에서는 과학사적 관점을 토대로 온도와 열의 개념 유형을 구분하고, 초등 중등학교 과학 교과서에서 열과 온도에 대해 진술하는 개념을 분석하여 학생들이 가질 수 있는 오개념의 원인을 파악하고자 하였다. 분석 결과, 초등학교부터 고등학교까지 과학 및 화학, 물리 교과서에서 제시하는 열과 온도의 개념이 현대적인 관점을 제시하지 못하고, 과학사적으로 변천해온 개념들이 뒤섞여서 제시되고 있다. 이러한 문제점은 학생들이 열과 온도에 대한 정확한 개념을 호기득하는데 방해가 될 수 있을 것이다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.427-430
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• 2015

Background: Dokha is a novel form of smoking in United Arab Emirates (UAE) on which there is very little published literature, especially among adolescents, and this form of smoking has been not been addressed adequately in the smoking cessation strategies in the UAE. Objectives: To assess the prevalence of dokha smoking among male secondary school students in Ajman UAE. Materials and Methods: A cross sectional survey was conducted among male secondary school students in Ajman, UAE. A total of 560 participants filled in self-administered questionnaires. Results: The prevalence of ever smokers was 39%; ever dokha smokers was 36% and current dokha smokers was 24%. The prevalence is very high when compared to other forms of smoking in the region and globally. Prevalence increased with increasing age and grade of students, prevalence of ever smokers, ever dokha smokers and current dokha smokers was lower in students in the science stream. 40% of the smokers used dokha, cigarettes and shisha, 30% used dokha and cigarettes, and 21% used dokha alone. 30% of the students smoked dokha on all days of the month. Conclusions: The prevalence of ever smokers, ever dokha smokers and current dokha smokers is very high. There is an urgent need for specific health promotion programs tailored to this age group on prevention of dokha smoking and policies restricting the availability of dokha to this age group.

• Journal of Power Electronics
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• 제19권2호
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• pp.403-412
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• 2019

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

• Journal of Korean Neurosurgical Society
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• 제46권4호
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• pp.417-420
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• 2009

The purpose of this report is to describe our surgical experiences in the treatment of cerebral decompression with in situ floating resin cranioplasty. We included in this retrospective study 7 patients who underwent in situ floating resin cranioplasty for cerebral decompression between December 2006 and March 2008. Of these patients, 3 patients had traumatic brain injury, 3 cerebral infarction, and one subarachnoid hemorrhage due to aneurysmal rupture. In situ floating resin cranioplasty for cerebral decompression can reduce complications related to the absence of a bone flap and allow reconstruction by secondary cranioplasty without difficulty. Furthermore, it provides cerebral protection and selectively eliminates the need for secondary cranioplasty in elderly patients or patients who have experienced unfavorable outcome.

• Journal of Korean Neurosurgical Society
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• 제64권3호
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• pp.367-373
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• 2021

Secondary neurulation (SN) is a critical process to form the neural tube in the posterior region of the body including the tail. SN is distinct from the anteriorly occurring primary neurulation (PN); whereas the PN proceeds by folding an epithelial neural plate, SN precursors arise from a specified epiblast by epithelial-to-mesenchymal transition (EMT), and undergo self-renewal in the tail bud. They finally differentiate into the neural tube through mesenchymal-to-epithelial transition (MET). We here overview recent progresses in the studies of SN with a particular focus on the regulation of cell lineage, self-renewal, and EMT/MET. Cellular mechanisms underlying SN help to understand the functional diversity of the tail in vertebrates.

• 농업생명과학연구
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• 제46권6호
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• pp.165-171
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• 2012

As a preceding study for investigating the influence of sound wave stimulus on Arabidopsis thaliana metabolomics, the polar secondary metabolomes of the plant were determined using high performance liquid chromatography coupled with tandem mass spectrometry. A total of 10 polar secondary metabolomes were characterized and quantified. Among them, 4 metabolomes, p-coumaroylagmatine isomer (7 and 8), p-coumaroylagmatine isomer (9 and 10) were identified in the plant for the first time. The validation was conducted in terms of linearity, recovery, precision, limit of detection (LOD) and limit of quantification (LOQ). The validated method was applied to the simultaneous quantification of the 10 polar secondary metabolomes.

• Nuclear Engineering and Technology
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• 제44권5호
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• pp.491-500
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• 2012

The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권1호
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• pp.55-62
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• 2007

구순열의 일차 수술 또는 이차 수술 후에 발생하는 상순의 지나친 긴장은 상하순 간의 부조화, 상악열성장, 골격성 III급 부정교합 등 안모추형을 초래한다. 상순의 긴장이 매우 심한 경우에는 하순의 여유 있는 조직을 이용하여 상순을 수정하는 Abbe 피판을 고려할 수 있다. 상순의 긴장이 큐피드궁의 2/3 이상의 조직 손실을 동반할 경우 Abbe 피판의 적응증이 된다. Abbe 피판은 상순과 하순의 반흔, 색상의 부조화, 그리고 상순의 불완전한 운동을 초래하는 단점을 가진다. 그러므로 Abbe 피판은 신중하게 사용되어야 한다. 우리는 편측성 구순열 1예와 양측성 구순열 3예에서 상순의 과도한 긴장과 큐피드궁의 조직 결핍 그리고 비변형이 심한 이차성 구순열비변형을 교정하기 위해 세 가지 형태의 Abbe 피판을 이용한 이차 교정술을 경험하였다. Abbe 피판수술을 시행한 결과 상순의 반흔과 긴장이 해소되고 큐피드궁이 재건되고 비주의 길이가 증가되어 이차 구순열비변형을 교정할 수 있었다. Abbe 피판은 신중을 기해 적용한다면 구순열 수술 후에 발생되는 상순의 수평적 긴장감이나 편평함을 해결하는 데 유용한 술식임을 알 수 있었다.