• 한국산학기술학회논문지
• /
• 제13권10호
• /
• pp.4822-4831
• /
• 2012

2000년대는 7차 교육과정에 따른 교과교실제의 적용, BTL사업의 시행 등 학교 건축에 영향을 미치는 교육시설정책상의 변화가 나타났던 시기였다. 특히 '열린교실'이라는 키워드가 있었던 초등학교와 달리 '교과교실'이라는 새로운 키워드가 등장했던 중등학교에서는 새로운 학교건축의 출현이 기대되던 시기이기도 하다. 따라서 2000년대 중등학교 건축은 주목하여 살펴볼 필요가 있다. 이에 본 연구는 일차적으로 2000년대 중학교 건축을 대상으로 그 건축적 특성을 살펴보고자 하였다. 이를 위해 에듀맥의 '우수학교 설계자료집'에 소개된 18개 중학교들을 대상으로 배치계획과 각 영역별 계획특성을 분석하였고 이를 종합하여 2000년대 중학교 건축에 나타나는 계획특성을 정리하고 개선점을 제시하였다. 분석결과 사례대상교들은 단위교실, 블록플랜 등의 계획영역에서 기존 학교건축의 전형적 특성인 남향위주의 계획방식이 유지되는 가운데 교사동 내외부의 공간구성은 다양해졌으며, 시설구성도 충실해진 특성을 보였다. 하지만 도시건축적 특성이나 전통성, 지역성 등의 표현 그리고 새로운 학교건축을 제안하기 위한 실험에서는 적극적이지 못했던 한계도 갖는다.

• International Journal of Precision Engineering and Manufacturing
• /
• 제8권1호
• /
• pp.73-78
• /
• 2007

The objective of this work was to simulate lead frame etching characteristics to optimize the etching process, Characteristics such as the etching factor and uniformity were investigated for different actual operating conditions, including pressure, distance from the nozzle tip, pipe pitch, and feed speed. The correlation between the etching and spray characteristics was analyzed to develop the etching model. Spray characteristics obtained from an experiment using a phase Doppler anemometer system were then simulated using a Monte-Carlo technique, The etching process model was coded in the Java language, The spray and etching characteristics were correlated with each other and simulated results agreed well with the measured data for a lead frame etching process, The optimal operating parameters under various conditions were successfully determined.

• Journal of Periodontal and Implant Science
• /
• 제34권2호
• /
• pp.317-332
• /
• 2004

Osteoblasts from alveolar bone may have an important role in the bone regeneration for periodontium, but their culture and characterization are not determined yet. The purpose of this study was to investigate the biological characteristics of primary explant cultured osteoblasts(PECO) from alveolar bone. Osteoblasts were isolated and cultured from alveolar socket of extracted tooth in children. To compare the characteristics, osteoblasts and gingival fibroblasts were cultured with DMEM at $37^{\circ}C$, 5% $CO_2$, l00% humidity incubator, and human fetal osteoblasts cell line(hFOB1) were cultured with DMEM at $34^{\circ}C$, 5%, $CO_2$ 100% humidity incubator. To characterize the isolated bone cells, morphologic change, cell proliferation and differentiation were measured. Morphology of PECO was small round body or cuboidal shape on inverted microscope and was similar with hFOB1. PECO became polygonal shape with stellate and had an amorphous shape at 9th passage in culture. PECO had significantly higher activity than that of gingival fibroblasts and hFOB1 in alkaline phosphatase activity. The expression of osteocalcin and bone sialoprotein in PECO was notably increased when compared with hFOB1 and gingival fibroblasts. These result indicated that PECO from alveolar bone in children has an obvious characteristics of osteoblast, maybe applied for the regeneration of bone.

• 과학교육연구지
• /
• 제38권2호
• /
• pp.331-343
• /
• 2014

전지의 연결방법에 따른 전류의 특성에 대한 초등교사들의 오개념 유형과 그 일관성에 대하여 조사되었다. 초등교사들의 전지의 연결방법에 따른 전류의 특성에 대한 오개념은 3가지 유형으로 나타났다. 14명의 초등교사들을 대상으로 한 이 연구에서, 전지들의 직렬연결과 병렬연결시 전류의 특성을 연결하는 전지의 수에 초점을 맞추는 유형에는 2명의 초등교사가, 전지의 직렬연결에 대한 개념과 병렬연결에 대한 개념을 혼동하는 유형에는 8명의 초등교사가, 그리고 전지의 직렬연결과 병렬연결에 대한 개념을 저항의 직렬연결과 병렬연결에 대한 개념으로 혼동하는 유형에는 4명의 초등교사가 분포하였다. 초등교사들은 전지의 연결에 대한 학습개념이 적용되는 상황에서 뿐만 아니라 분화개념이 적용되어야 하는 상황에서도 그들의 오개념 유형을 일관성 있게 적용하고 있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 C
• /
• pp.2090-2092
• /
• 2004

In this paper, the new measurement methodology of characteristics of the vibratory micro gyroscope using Quality factor and the resonant displacement was proposed. Because the Quality factor has a large error under the high Quality factor condition, it is difficult to analyze the characteristics of the vacuum packaged vibratory micro gyroscopes with the Quality factor. We analyzed mechanical characteristics of gyroscope with the value of Quality factor. We described measurement errors of mechanical characteristics of micro gyroscopes. The measured value of Quality factor is 47532 and error range of Quality factor is from -29.8 % to 73.9 %. The value of resonant displacement is 3.4${\mu}m$ and the measurement error is 2.9 %. From the result of Quality factor degradation and resonant displacement degradation, 1698 days and 1503 days were estimated as Time To Failure (TTF), respectively. The range of estimation error of Quality factor degradation and resonant displacement degradation is calculated from 1246 days to 1832 days and from 1456 days to 1537 days, respectively. We can analyze the characteristics of the vibratory gyroscope using the quality factor when the Quality factor is smaller than 10,000. Also we can analyze that using the resonant displacement when the Quality factor is larger than 10,000.

• Tribology and Lubricants
• /
• 제26권1호
• /
• pp.7-13
• /
• 2010

This experimental study presents tribological characteristics under boundary lubrication contacts associated with electrorheolocal (ER) fluid. ER fluid is prepared by using phosphorated starch particles and silicone oil. Experimental apparatus of tribological tester is designed and constructed to evaluate tribological characteristics of pin specimens. Wear tests under boundary lubrication of ER fluid are experimentally performed under consideration of several operational factors such as normal load, sliding distance, sliding speed and specimen materials: steel, copper and aluminum. After wear test, microscopic surface changes of the worn pin specimens are analyzed in order to investigate measured wear characteristics by using the scanning electron microscope (SEM) as well as surface profilometer. In addition, the chemical wear characteristics are investigated by using energy dispersive x-ray spectroscopy (EDS). Moreover, friction coefficient measurements under different materials of pin specimens are conducted for the tribological investigations. In order to verify the effect of starch phosphate particles in ER fluid, the wear test results with ER fluid are compared with test results with only silicone oil. The results clearly present that the phosphorated starch based ER fluid shows the stabilized wear as well as friction characteristics after run-in operations, but the wear rate under ER fluid is increased.

• 한국초등과학교육학회지:초등과학교육
• /
• 제25권4호
• /
• pp.396-406
• /
• 2006

In this study, elementary school students' science learning characteristics together with the levels of inquiry requirement in elementary school science experiment instruction were investigated in terms of the affective domain. We divided seventy-three students of the fifth ade into two groups according to the levels of inquiry requirement. After each instruction had been implemented, the characteristics of the students' learning in terms of the affective domain were compared and analyzed within the context of the levels of inquiry requirement. There were no significant differences between Level 1(LL) and Level 2(HL) groups in terms of the affective characteristics. These results may be caused by the burden imposed by the difficulty in thinking through and setting up the experimental methods. However, the HL group students' levels of interest in science experiments was higher than that of the LL group. In conclusion, the HL instruction contributed little to the improvement of affective characteristics. Some possible reasons might be that students felt difficulties with the somewhat unfamiliar instructions which required them to design and perform experiments. Higher levels of interest in science experiments amongst HL students' implies that well-organized and continuous exercises involving the design and performance of experiments could improve students' scientific affective characteristics.

• Wind and Structures
• /
• 제39권2호
• /
• pp.141-161
• /
• 2024

Engineering structures often suffer significant damage in the horizontal outflow region of downburst. The wall jet model, which simplifies the simulation device by only modeling the horizontal outflow region of downburst, has been widely employed to study downburst flow characteristics. However, research on downburst wind fields over hilly terrain using the wall jet model is limited, and the relationship between the downburst wind fields generated by wall jet and impinging jet remains unclear. This study investigates the flow characteristics of downburst-like wind over a 3D ideal hill model using wind tunnel tests with the wall jet and impinging jet models. The effects of hill height, slope, shape, and radial position on the speed-up ratio are examined using the wall jet flow. The results indicate that slope and radial position significantly affect the speed-up ratio, while hill height have a slight impact and shape have a minimal impact. Additionally, this study investigates the wind field characteristics over flat terrain using the impinging jet, and investigated the connection between the impinging jet model and the wall jet. Based on this connection, a comparison of the downburst-like flow characteristics over the same 3D ideal hill using the wall jet and impinging jet models is conducted, which further validates the reliability of the wall jet model for studying downburst flow characteristics over hilly terrain.

• 한국수소및신에너지학회논문집
• /
• 제29권1호
• /
• pp.81-89
• /
• 2018

Fuel blend technique is one of the most effective way of using biomass to replace the coal. Many studies on combustion characteristics with coal and biomass blends have been conducted. In this study, char reactivity and emission characteristics of coal (Suek) and biomass (EFB) blends has been investigated by TGA and DTF to evaluate the applicability of the pre-treated (torrefaction, ash removal technology) EFB to pulverized coal boiler. In all blending cases, char reactivity improved as the blending ratio increases (10, 20, and 30%), especially torrefied EFB blended at 30%. Also, unburned carbon decreased as the blending ratio increases in all types of EFB. NOx emission showed the increase and decrease characteristics according to the content of fuel-N of raw EFB and torrefied EFB. But the amount of NOx emission at ashless EFB blends is greater than that of Suek despite of lower fuel-N. It indicated that co-firing effect of using the pretreatment biomass fuel is relatively better than those of the untreated biomass fuel about char reactivity and emission characteristics.

• 대한지구과학교육학회지
• /
• 제1권1호
• /
• pp.41-51
• /
• 2008

For teaching-learning to geological region of earth science part in science education, middle school, the practical uses of natural science museum are very effective. So, the appropriate uses of the natural science museum are necessary for the teaching and learning of Science Education. This study aims to consider the presentation characteristics of the natural science museum and to examine how is effective it to geological region in middle school science curricula on those uses. From the results, the natural science museum is low in multi-sided and open-endedness presentation characteristics but high in ones of accessible characteristic. And its presentations are good in multimodal characteristics using supported materials but relatively low in relevant and multimedia ones. In the museum, diorama and self-performing presentation types are not but internet ones are most. The presentations of the natural science museum are mainly assigned to knowledge region linked to basic science concepts but relatively insufficient in STS aspects, on the basis of connection the presentations with middle school science curricula. It is respected that these insufficiencies might be diminished by variable arrangements of and explanations to the presentations for understanding improvements. And, applies to the presentations in STS may be encountered, if multi-sided observations to them is available.