• 공학교육연구
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• 제20권4호
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• pp.21-27
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• 2017

The purpose of this study is to provide basic data and guideline to STEM(Science, Technology, Engineering, Mathematics) educators who prepare engineering education in elementary and secondary school. For this, this study develops a composition model for engineering education program of elementary and secondary school. To do this, a literature research, experts interview and Delphi survey were conducted. Through the literature research, we extracted the components of model for engineering education program of elementary and secondary school and then made a first draft of the model. The draft was revised by experts while Delphi survey was used to validate the model based on Delphi panels' opinions. The panels for the Delphi survey consisted of 51 experts in the STEM education field. The survey was conducted three different times and importance survey was included in the third stage. The conclusions of this study were as follows: First, the model consist of definition, 4 directions, 4 characteristics, 3 educational goals according to school level, educational contents area and element, teaching and learning method and evaluation method. The educational contents area and element consist of 2 major areas, 7 areas and 18 elements. Second, all components of the developed model were valid in most of the statistics such as mean, standard deviation, the degree of consensus and convergence, and CVR(Content Validity Ratio). Third, importance for education contents area and element according to the school level are analyzed.

• 한국지형학회지
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• 제23권2호
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• pp.95-108
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• 2016

Several flights of marine terraces were developed along the Eastern coast of Korea (Gangneung-Donghae). Various dating techniques have been applied to determine the age of these terraces, with a view to better understand the regional uplift history. In this study, we compare the major element compositions of the terrace deposits and modern beach sediments to estimate the relative formation age of these terraces. We observed a discernible difference in major element geochemistry between modern beach sediments and various elevated terrace deposit (i.e. palaeobeach sediments). In general, weathering properties of marine terrace sediments are expected to be affected by the formation ages of terraces, and here, we confirm that the chemical composition are indicative of the relative age of the terraces in this region.

• 한국대기환경학회지
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• 제12권4호
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• pp.377-387
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• 1996

This study was carried out to monitor the visibility including measurement and analysis of the various parameters such as particle size distribution, chemical composition, and meteorotical conditions to understand the characteristics and causes of this phenomenon. According to the analysis of intensive sampling, $SO_4^{2-}, NO-3^-, Cl^-, NH_4^+$ ion concentration increased together with the mass concentration around 1 $\mu$m in the case of low visibility. $(NH_4)_2SO_4, NH_4NO_3$, and $NH_4Cl$ were thought to be the major components of fine particles. The statistical analysis showed that the scattering effect of particle was 81.2%, the absorption effect was 14.9%. Therefore, these effects were the major factors to reduce the visibility. In conclusion, the visibility was reduced by the fine particle of sulfate (18.6%), nitrate (14.2%), organic carbon (10.8%), element carbon (25.8%), and residual (24.8%) during this study.

• 자원환경지질
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• 제29권2호
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• pp.171-182
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• 1996

제 4기 전곡현무암은 추가령 열곡대내의 한탄강유로를 따라 길게 분포하고 있으며 이대성 외 (1983)에 의하면 대략 10-20 m정도의 두께를 가지고 있다. 전곡현무암의 암석분화 과정을 밝히기 위해 57개의 시료가 채취 되었으며, 이중 16개의 시료에 대한 주성분 및 미량원소의 화학분석이 실시되었다. 분석된 시료들의 화학조성에 의하면 전곡현무암은 알칼리계열의 현무암으로 특징지워지며, MgO를 제외한 주성분원소의 변화범위가 미량원소에 비하여 상당히 좁은 영역을 나타낸다. 분별결정작용 모델을 정량적으로 시험하기 위해서 Multiple linear regression을 사용하였다. 주성분원소와 반정으로 산출되는 광물의 화학조성을 사용하여 계산된 결과는 전곡현무암의 화학조성의 변화는 감람석, 사장석, 휘석, 자철석이 56 : 25 : 17 : 2의 비율로 분별정출되어 분화된 것으로 설명할 수 있다. 그러나 위의 결과를 가지고 미량원소의 함량을 계산하면 불호정 (incompatible) 원소의 계산치는 딸암석의 실제 함량에 미치지 못한다. 이러한 점으로 미루어 전곡현무암의 화학조성의 변화는 광물들의 단순한 분별정출 작용만으로는 설명하기가 어렵다. 따라서 전곡현무암의 화학조성의 변화는 약간 다른 정도의 부분용융에 의해 불호정 원소의 초기치가 다른 것들이 분별정출과정을 겪었거나, 혹은 RTF과정에 의한 불호정원소의 부화가능성을 배제할 수 없음을 시사한다.

• 암석학회지
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• 제19권3호
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• pp.181-197
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• 2010

고대 도 토기와 같은 고고학 유물을 만든 원료(태토)의 기원지 규명에 적합한 지구과학적 인자를 도출하기위한 연구를 수행하였다. 연구방법은 경북 경주, 경산 및 경남 함안지역에서 생산되었거나 출토된 토기와 토기채취지역 주변에 분포하는 암석과 토양을 채취하여 이들의 광물조성 및 화학조성을 비교하였다. 연구결과에 의하면, 토기는 구워지면서 광물조성이 바뀌기 때문에 광물조성의 비교에 의한 태토 및 원암의 유추는 어려운 것으로 나타났다. 그리고 주성분조성을 이용한 일반적인 화학조성간의 상대적인 비교 또한 원암-태토(토양)-토기로 가면서 대부분의 화학조성비가 변하기 때문에 상호간의 상관성이 거의 없음을 확인하였다. 반면에 희토류원소 분포도는 암석-토양-토기로 진행되면서 상대적인 분포도가 주성분조성변화에 비해 거의 없고, 희토류원소의 하나인 Nd의 동위원소비에 의한 모델연대에서도 유사성을 보여주었다. 그리고 Nd 동위원소와 Sr 동위원소 또한 태토와 토기간에 연관성이 있음을 보여주었다. 이 연구결과 고고학적 유물의 재료를 밝혀내는데 있어서 희토류원소의 분포도와 Nd, Sr 동위원소의 지구화학적 특성이 다른 지구화학적 연구기법에 기법에 비해 더 유용하게 활용될 수 있음을 확인할 수가 있었다.

• 한국환경과학회지
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• 제27권7호
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• pp.543-554
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• 2018

From November 2013 to December 2016, ambient fine particulate matter ($PM_{2.5}$) was sampled in the downtown area of Jeju City, South Korea, which has seen rapid urbanization. The atmospheric concentrations of elements were measured in the $PM_{2.5}$ samples. This study focused on Cd, Cr, Cu, Mn, Ni, Pb, As, Sb, Sn, V, and Zn. The concentrations of Al, Na, K, Fe, Ca, Mg, Sr, and La were also obtained for reference. The objectives of this study were to examine the contributions of these elements to $PM_{2.5}$ concentrations in downtown Jeju City, and to investigate the inter-element relationships and the elemental sources by using enrichment factors and principal components analysis (PCA). A composition analysis showed that the 19 elements constituted 6.65 % of the $PM_{2.5}$ mass, and Na, K, Al, Fe, Ca, Mg, and Zn constituted 98 % of the total ion mass. Seasonal trend analysis for the sampling period indicated that the concentrations of the elements increased from November to April. However, no substantial seasonal variations were found in the concentrations of the elements. The composition ratios of some elements (Cu/Zn, Cu/Cd, Cu/Pb, V/Ni, and V/La) were found to be out of range when compared to the literature from other urban areas. The ratios between the elements and the PCA results showed that local contaminant sources in Jeju City rarely influence the composition of $PM_{2.5}$. This suggests that the major sources of $PM_{2.5}$ in Jeju City may include long-range transport of fine particulate matter produced in other areas.

• International Journal of Advanced Culture Technology
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• 제12권3호
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• pp.370-379
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• 2024

In this paper, we explore the historical development and revolutionary impact of music in mass media across various forms, including radio, television, film, and digital platforms. The evolution of music in mass media reflects significant technological and cultural shifts over the past century. From the early days of radio to the advent of digital streaming, music has played a crucial role in shaping the types of mass media. Early radio broadcasts in the 1920s relied on live performances and recordings to captivate audiences, establishing music as a central element of media content. The rise of television in the 1950s brought new opportunities for music integration, with theme songs, variety shows, and music videos becoming staples of TV programming. The film industry further revolutionized the use of music, with iconic scores enhancing cinematic storytelling and emotional depth. The digital revolution of the late 20th century introduced new formats and services, expanding access to music and transforming consumption patterns. Recently, streaming platforms and social media allow for personalized music experiences and direct artist-fan interactions. Through an analysis of technological advancements, this study highlights the integral role of music in enhancing narrative, evoking emotions, and creating cultural identities. We present our understanding of this evolution to provide insights into future trends and potential innovations in the integration of music with mass media, including the use of artificial intelligence and virtual reality to create immersive auditory experiences.

• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.63-71
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• 2002

The thermal desorption-gas chromatographic (TD-GC) system has been constructed for the measurement of volatile organic compounds. The thermal desortion unit is composed of four major parts: 1) the control part; 2) the thermal desorption part; 3) the focusing part; and 4) the injection part. The peltier element was introduced to the focusing part for the temperature of the focusing tube to reach-35$^{\circ}C$. The system was tested for the linearity of the calibration curves and reproducibility of instrumental analyses using some disinfection by-products (DBPs) and BTXs (benzene, toluene and p-xylene). The coefficients of determination (r$^2$) for all the calibration curves made were higher than 0.998, and the coefficients of variation (CV) for triplicate measurements were all within 10％. The system also has been tested for field applicability. The analysis of field samples showed that there was no breakthrough problem in the sampling system and that the system could be applied to field measurements.

• 자원환경지질
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• 제31권2호
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• pp.111-125
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• 1998

Dispersion, migration and enrichment of environmental toxic elements from the Samkwang Au-Ag mine area were investigated based upon major, minor and rare earth element geochemistry. The Samkwang mine area composed mainly of Precambrian granitic gneiss. The mine had been mined for gold and silver, but closed in 1996. According to the X-ray powder diffraction, mineral composition of stream sediments and soils were partly variable mineralogy, which are composed of quartz, orthoclase, plagioclase, amphibole, muscovite, biotite and chlorite, respectively. Major element variations of the host granitic gneiss, stream sediments and soils of mining and non-mining drainage, indicate that those compositions are decrese $Al_2O_3$, $Fe_2O_3$, MgO, $TiO_2$, $P_2O_5$ and LOI with increasing $SiO_2$ respectively. Average compositional ranges (ppm) of minor and/or environmental toxic elements within those samples are revealed as As=<2-4500, Cd=<1-24, Cu=6-117, Sb=1-29, Pb=17-1377 and Zn=32-938, which are extremely high concentrations of sediments from the mining drainage (As=2006, Cd=l1, Cu=71, Pb=587 and Zn=481 ppm, respectively) than concentrations of the other samples and host granitic gneiss. Major elements (average enrichment index=6.53) in all samples are mostly enriched, excepting $SiO_2$, $Na_2O$ and $K_2O$, normalized by composition of host granitic gneiss. Rare earth element (average enrichment index=2.34) are enriched with the sediments from the mining drainage. Minor and/or environmental toxic elements within all samples on the basis of host rock were strongly enriched of all elements (especially As, Br, Cu, Pb and Zn), excepting Ba, Cr, Rb and Sr. Average enrichment index of trace elements in all samples is 15.55 (sediments of mining drainage=37.33). Potentially toxic elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) of the samples revealed that average enrichment index is 46.10 (sediments of mining drainage=80.20, sediments of nonmining drainage=5.35, sediments of confluent drainage=20.22, subsurface soils of mining drainage=7.97 and subsurface soils of non-mining drainage=4.15). Sediments and soils of highly concentrated toxic elements are contained some pyrite, arsenopyrite, sphalerite, galena and goethite.

• 자원환경지질
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• 제31권4호
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• pp.297-310
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• 1998

Geochemical characteristics of environmental toxic elements at the Narim mine area were investigated on the basis of major, minor, rare earth element geochemistry and mineralogy. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in soils and sediments range from 11.57 to 22.21 and from 1.86 to 3.93, and are partly negative and positive correlation against $SiO_2/Al_2O_3$ (3.41 to 4.78), respectively. These suggested that sediment source of host granitic gneiss could be due to rocks of high grade metamorphism originated by sedimentary rocks. Characteristics of some trace and rare earth elements of V/Ni (0.33 to 1.95), Ni/Co (2.00 to 6.50), Zr/Hf (11.27 to 53.10), La/Ce (0.44 to 0.55), Th/Yb (4.07 to 7.14), La/Th (2.35 to 3.93), $La_N/Yb_N$ (6.58 to 13.67), Co/Th (0.63 to 2.68), La/Sc (3.29 to 5.94) and Sc/Th (0.49 to 1.00) are revealed a narrow range and homogeneous compositions may be explained by simple source lithology. Major elements in all samples are enriched $Al_2O_3$, MgO, $TiO_2$ and LOI, especially $Fe_2O_3$ (mean=7.36 wt.%) in sediments than the composition of host granitic gneiss. The average enrichment indices of major and rare earth elements from the mining drainage are 2.05 and 2.91 of the sediments and are 2.02 and 2.60 of the soils, normalizing by composition of host granitic gneiss, respectively. Average composition (ppm) of minor and/or environmental toxic elements in sediments and soils are Ag=14 and 1, As=199 and 14, Cd=22 and 1, Cu=215 and 42, Pb=1770 and 65, Sb=18 and 3, Zn=3333 and 170, respectively, and extremely high concentrations are found in the subsurface sediments near the ore dump. Environmental toxic elements were strongly enriched in all samples, especially As, Cd, Cu, Pb, Sb and Zn. The level of enrichment was very severe in mining drainage sediments, while it was not so great in the soils. Based on the EPA value, enrichment index of toxic elements is 8.63 of mining drainage sediments and 0.54 of soils on the mining drainage. Mineral composition of soils and sediments near the mining area were partly variable being composed of quartz, mica, feldspar, amphibole, chlorite and clay minerals. From the gravity separated mineralogy, soils and sediments are composed of some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, goethite and various hydroxide minerals.