• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.359-364
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• 2008

We have investigated optical and structural properties of $Al_{0.3}Ga_{0.7}N$/GaN and $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ heterostructures (HSs) grown by metal-organic chemical vapor deposition, by means of Hall measurement, high-resolution X-ray diffraction, and temperature- and excitation power-dependent photoluminescence (PL) spectroscopy. A strong GaN band edge emission and its longitudinal optical phonon replicas were observed for all the samples. At 10 K, a 2DEG-related PL peak located at ${\sim}\;3.445\;eV$ was observed for $Al_{0.3}Ga_{0.7}N$/GaN HS, while two 2DEG peaks at ${\sim}\;3.42$ and ${\sim}\;3.445\;eV$ were observed for $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ HS due to the additional $Al_{0.15}Ga_{0.85}N$ layers. Moreover, the emission intensity of the 2DEG peak was higher in $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ HS than in $Al_{0.3}Ga_{0.7}N$/GaN HS probably due to an effective confinement of the photo-excited holes by the additional $Al_{0.15}Ga_{0.85}N$ layers. The 2DEG-related emission intensity decreased with increasing temperature and disappeared at temperatures above 150 K. To investigate the origin of the new 2DEG peaks, the energy-band structure for multiple AlGaN/GaN HSs were simulated and compared with the experimental data. As a result, the observed high- and low-energy peaks of 2DEG can be attributed to the spatially-separated 2DEG emissions formed at different AlGaN/GaN heterointerfaces.

• Communications of Mathematical Education
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• v.16
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• pp.217-218
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• 2003

제7차 교육과정의 기본방향인 '21세기의 세계화 정보화 시대를 주도할 자율적이고 창의적인 한국인 육성'에서 볼 수 있듯이, 새로운 교육과정에서는 학생들의 창의력을 신장시키기 위한 방안으로 교과별 교육과정이나 재량활동 운영 등을 제시한 바 있다. 수학교육에서도 이러한 시대적 흐름에 발맞추어 수학적 창의력의 신장이 강조되고 있는 상황이다. 그동안 이론적인 측면과 실제적인 측면에서 수학적 창의성에 대한 성과가 축적되었다. 이론적인 측면에서 볼 때, Haylock(1987)등에 의해 창의력과 수학적 창의력의 구분되었으며, 특히 '수학적' 창의력에 대한 다양한 정의가 제안되었다. 실제적인 측면에서도 수학적 창의력을 측정하려는 평가 도구들이 그 동안 여러 가지로 개발하였다. 그러나, 이러한 수학적 창의력에 관한 전반적인 연구는 종국적으로 교실 수학수업에 반영되어야 함에도 불구하고, 그리 만족스럽지 못한 상황이다. 특히, 교실에서 수학수업을 실제로 담당하는 교사들이 수학적 창의력을 위한 수업을 하고자 하더라도 당장 가까이에서 구할 수 있는 교수 학습 자료가 여전히 부족한 상황이다. 물론 그 동안 교실 수학수업에서 사용할 수 있는 창의력 개발 프로그램이 전무한 것은 아니다. 그런데 그들 대부분은 게임이나 퍼즐을 이용한 것으로 그 수준이 단순 흥미유발에 그치고 있거나 소수의 영재아를 위한 소재를 중심으로, 특히 수학적 사고 과정을 따르기보다는, 시행착오를 거쳐 원하는 결과를 얻을 가능성이 많으며, 수학과의 연계성이 불분명한 채로 단순놀이에 그치는 경우가 적지 않아, 수업과 연관되어 창의력의 신장이라는 측면에서 볼 때, 적용하기 어려운 사례가 많다. 이러한 상황을 개선하는 데 기여하고자, 현재 교과교육공동연구 지원사업의 하나로 한국 학술 진흥재단의 지원을 받아, '개방형 문제(open-ended problems)'를 중심 소재로 한 '수학적 창의성'을 신장하기 위한 교수학습 프로그램을 개발하여, 중학교 1학년을 대상으로 연구를 진행하고 있다. 개방형 문제라 함은 명백한 정의가 어렵지만 Pehkeon(1995)는 개방형문제의 정의를 명백히 하기위한 시도로서 그 반대로 닫힌 문제에 대한 정의로부터 시작하여, 어떤 문제가 닫혀있다고 하는 것은 그 문제의 출발 상황과 목표 상황이 닫혀 있는 것, 즉 명백히 설명되어있을 때라면 개방형 문제는 이와 반대의 개념임을 시사하였다. Silver(1995)는 개방형 문제를 문제 자체가 다른 해석이 가능하거나 서로 다를 인정할만한 답을 가질 수 있는 문제 또는 풀이과정이 다양한 문제, 자연스럽게 다른 문제들을 제안하거나 일반화를 제시할 수 있는 문제라고 정의하였다. 따라서 개방형 문제란 출발상황이나 목표 상황의 일부가 닫혀있지 않을 때를 말하고 문제의 조건을 만족하는 해답이 여러 가지로 존재하는 문제를 뜻한다. 수학적 창의력을 개발하는 데, 다른 문제 유형보다도, 개방형 문제가 유리하다는 점은 이미 여러 학자들에 의해 주장되어왔다. 미국 국립영재교육센터(NRCG/T)는 기존의 사지선다형이나 단답형 문제와 질문들은 학생들의 사고 능력에 관한 정보를 거의 알려주지 못하기 때문에 한 가지 이상의 답을 요구하는 ‘open-ended' 또는 ’open-response' 문제와 질문을 가지고 수학 분야에서의 창의적 사고 능력과 표현능력을 측정해야 한다고 하였고, 개방형 문제가 일반적으로 정답이 하나인 문제보다 고차원적인 사고를 요구하게 하는 문제 형태라고 하였다. 본 연구에서는 이러한 근거를 바탕으로 개방형 문제의 유형을 다양한 답이 존재하는 문제, 다양한 해결 전략이 가능한 문제, 답이 없는 문제, 문제 만들기, 일반화가 가능한 문제 등으로 보고, 수학적 창의성 중 특히 확산적 사고에 초점을 맞추어 개방형 문제가 확산적 사고의 요소인 유창성, 독창성, 유연성 등에 각각 어떤 영향을 미치는지 20주의 프로그램을 개발, 진행하여 그 효과를 검증하고자 한다. 개방형 문제를 활용한 수학적 창의력 신장 프로그램을 개발하고 현장 학교에 실험 적용하여 그 효과를 분석하고자 하는 본 연구는 창의력 신장에 비중을 두는 수학과 교수-학습 과정에 실제적인 교수 학습 자료를 제공하는 것뿐만 아니라 교사들에게는 수학교실에서 사용 가능한 실제적인 활용방안을, 학생들에게는 주어진 문제를 여러 가지 각도에서 생각하면서 다양한 사고를 경험하는 기회를 가질 수 있어, 수학을 보는 학생들의 태도에도 긍정적인 변화를 가져올 수 있을 것이라 기대한다.

• Journal of Korean Home Economics Education Association
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• v.24 no.2
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• pp.29-49
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• 2012

The purpose of this study is to look at families as presented on the technology-home economics subject of middle school. To do this, I analyzed the 2007 revised curriculum of the technology-home economics subject, 'Changing Families,' in 11 technology-home economics textbooks (8th grade). The findings are as follows. First, family-related chapters are expanded compared with the previous curriculum in the 2007 revised curriculum. In addition, the new version emphasizes understanding and acceptance of change in families to improve the family life of adolescents. Second, in the 11 types of technology-home economics textbooks, the focusing was on the meaning of the family, the family structure, the function of the family, family roles and family values. There were also no major differences in the aspect of development. Third, in the technology-home economics textbooks, the family was defined as the 'basic group of society', 'a group composed by blood relationships, marriage and adoption', 'an affective group' and 'cohabiting group'. At the same time, there were many cases in which the description of the family was overly romanticized. Such a description of the family does not match the individual family experience of an adolescent. Fourth, all of textbooks dealt with the diversity of the family structure, such as single-parent families, remarriages families, and multi-cultural families. However, the structural characteristics and problems with these types of families are excessively emphasized, which can result in students having stereotypical images of specific family types. Fifth, the explanation of the function of the family was similar among textbooks. The importance of intergenerational cooperation and gender equality was also emphasized. However, such a concept is not considered as proper in a modern society. Thus, the description of a family based on the nuclear family should be sublated. In addition, the explanation of families overall should be developed in such a way that adolescents can interpret their own family experience rather than as an enlightening declaration of the family which disregards the dynamic relationships individual families actually experience.

• KDI Journal of Economic Policy
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• v.34 no.3
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• pp.1-29
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• 2012

Based on the spatial and land price data of innovation cities and their periphery areas in Korea, this study examines the degree and timing of changes in land price in relation to projects concerning innovation city. The study result confirms that the current system is inconsistent with the principle of restitution of development gain and therefore, this study attempts to seek improvement measures so that the current system can better fit the principle. The analysis reveals that most innovation cities, excluding Sinseo-dong of Daegu and Ujeong-dong of Ulsan, recorded a statistically significant increase in land prices since 2005, compared to those of their neighboring areas. It can be said that the information related to projects concerning innovation city was reflected in the land price since 2005. However, the standard land price pursuant to Article 70 of the Land Compensation Act is the officially assessed land price released on 1st of January 2007, and this official land price was actually applied to the compensation process. Therefore, estimating the compensation amount for land expropriation based on this land price will contradict the principle of restitution of development gain. In other words, despite the fact that development-related information was already reflected in land prices of innovation cities from 2005 to the end of 2006, the compensation process were carried out without institutional arrangements or efforts to exclude such reflection. To solve this problem, this study makes two suggestions. First, it is necessary to cast aside the limitations of the official land price that can be retroactively applied in accordance with Paragraph 5 of Article 70 of the Land Compensation Act, and instead apply the land price which is the most latest but deemed to have no reflection of development gains. Based on this revised standard land price, if the compensation amount is corrected by the average inflation rate and the average rate of increase in land price during the period until the time of the recognized land price, the amount would better satisfy the principle of restitution of development gain. Second, it is necessary to clearly stipulate the standards of development gains being reflected on the land price by including it in the secondary legislation. Under the current system, it is highly likely that appraiser's arbitrary interpretation on development gains is included in the process of calculating the amount of compensation for land expropriation. In this regard, it is necessary to improve the standards on determining whether development gains are reflected based on the results of this academic research and the existing guidelines for appraisal of compensation for land expropriation published by the Korea Association of Property Appraisers.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.4
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• pp.36-48
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• 2010

The objectives of this study are to research and analyze the positioning of Mt. Back Hwa(白華山) and the characteristics of its neighboring cultural scenery based on the Two Seated Buddah Temple, a small Buddhist temple of Taeul in Taean and to view both landscape geographic codes and religious attractions over Mt. Back Hwa by discussing its expression and meaning for the scenery scattered or nested over this districts. The panoramic view of west shows the character of Mt. Back Hwa as a magnanimity of Buddhist Goddess of Mercy which is viewed as a view point field no less than its location as a landscape target and its singularity as a rocky mountain. The ancient castle, signal beacon post and the small Buddhist temple of Taeul to be read importantly in the old map and SinjeungDongkukyeojiseungram(新增東國輿地勝覽) form the core of place identity, and a number of carve(engrave) letters such as Eopungdae(御風臺), Youngsadae(永思臺), etc. show the prospect of this mountain and monumentality derived from place characteristics. In addition removing of Taeiljeon, a portrait scroll of Dangun, national ancestor makes possible to guess the national status hold by Mt. Back Hwa in advance and to know that it has symbiotic relationship with indigenous religion and shares with the universal locality which have been continued for a long time through a portrait scroll of Dangun enshrined in Samsunggak. More than anything else, however the Rock-carved Buddha Triad in Taean, Giant Buddha of Baekjae era enshrined in the small Buddhist temple of Taeul is not only why Mt. Back Hwa, magnanimity of Buddhist Goddess of Mercy exists but also a signifier. In spite of such a placity, the union ideas of confucianism, buddhism and doctrinism of buddhism prevailed in the Late Joseon Dynasty allows the cultural phenomenon of taoism to be read in the same weight through Ilsogae(一笑溪) and Gammodae(感慕臺) which are mountain stream and pond area respectively centered in the carve letter, 'Taeeuldongcheon(太乙洞天)' constructed in front of the small Buddhist temple of Taeul, the Baduk board type of rock carvings engraved over them and a number of traces of carve letters made by confucian scholars since the Middle of Joseon Dynasty. The reason such various cultural sceneries are mixed in Mt. Back Hwa is in the results of inheritance of religious places and fusion of sprit of the times, and the various type of cultural scenery elements scattered in Mt. Back Hwa are deemed as unique geographic code to understand the multi-layered placity and the characteristics of scenery of Mt. Back Hwa in Taean.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.3
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• pp.160-171
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• 2018

This study aims to find an original form of temple flower decoration patterns, considering floral lattice pattern as a view element composing temple landscape. To that end, we analyzed and interpreted the form and symbol expressed in the floral lattice pattern at Nahanjeon of Seonghyel Temple at Yeongju, Gyeongsangbukdo. The front side of Nahanjeon windows shows a sculpture with 176 pure patterns in a form where two squares are in sequence. The basic concept of main front door (the inner gate of Nahanjeon) frames is considered the design language of lotus pond that symbolizes "square land" in traditional gardens. The four leaf clover and arrowhead are water plants discovered in areas nearby ponds, which are a realistic expression conforming to the water ecology of lotus pond. The lotus, which is the most important plant at the main front door, indicates purity, a non-stained state, and the world of the lotus sanctuary, which is the land of blissful happiness in Buddhism. The lotus expressed in the floral lattice pattern is spread in a diverse form, containing the features of creation and destruction, showing the landscape character of the "One Body of Buddha and Lotus". The expression of flying birds such as kingfishers and egrets is an ecologically aesthetic idea to infuse dynamism and vitality into a seemingly static aquatic ecosystem. The floral lattice pattern contains lotus pond scenery showing symbiosis of animals(i.e., dragons, frogs, crabs, fishes, egrets, wild geese, and kingfishers) and plants(i.e., four leaf clovers and arrowheads), which are symbols of relief faith for longevity, wealth, preciousness, and many sons. The pattern is not just an ecological aesthetic expression but a holistic harmony of ecological components such as growth and disappearance of lotus and its leaves, fitting habitats, symbiosis, and food chain.

• The Journal of Engineering Geology
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• v.16 no.4 s.50
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• pp.411-427
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• 2006

This study aimed to recognize characteristics of groundwater flow in fractured bedrocks based on zonal pump-ing tests, slug tests, water quality logs and borehole TV camera logs conducted on two boreholes (NJ-11 and SJ-8) in the city of Naju. Especially, the zonal pumping tests using sin91e Packer were executed to reveal groundwater flow characteristics in the fractured bedrocks with depth. On borehole NJ-11, the zonal pumping tests resulted in a flow dimension of 1.6 with a packer depth of 56.9 meters. It also resulted in lower flow dimensions as moving to shallower packer depths, reaching a flow dimension of 1 at a 24 meter packer depth. This fact indicates that uniform permissive fractures take place in deeper zones at the borehole. On borehole SJ-8, a flow dimension of 1.7 was determined at the deepest packer level (50 m). Next, a dimension of 1.8 was obtained at 32 meters of packer depth, and lastly a dimension of 1.4 at 19 meters of packer depth. The variation of flow dimension with different packer depths is interpreted by the variability of permissive fractures with depth. Zonal pumping tests led to the utilization of the Moench (1984) dual-porosity model because hydraulic characteristics in the test holes were most suitable to the fractured bedrocks. Water quality logs displayed a tendency to increase geothermal temperature, to increase pH and to decrease dissolved oxygen. In addition, there was an increasing tendency towards electrical conductance and a decreasing tendency towards dissolved oxygen at most fracture zones.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.557-576
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• 2015

Groundwaters in granite, gneiss, and two-mica granite formations, including faults, in the Hoengseong area are examined to determine the relationship between their uranium and radon-222 contents and rock types. The chemical compositions of 38 groundwater samples and four surface water samples collected in the study area were analyzed. Sixteen of the samples showing high uranium and radon-222 contents were repeatedly analyzed. Surface radioactivities were measured at 30 points. The uranium and radon-222 concentrations in the groundwater samples were in the ranges of 0.02-49.3 μg/L and 20-906 Bq/L, respectively. Four samples for uranium and 35 samples for radon had concentrations exceeding the alternative maximum contaminant level of the US EPA. The chemical compositions of groundwaters indicated Ca(Na)-HCO₃ and Ca(Na)-NO₃(HCO₃+Cl) types. The pH values ranged from 5.71 to 8.66. High uranium and radon-222 contents in the groundwaters occurred mainly at the boundary between granite and gneiss, and in the granite area. The occurrence of uranium did not show any distinct relationship to that of radon-222. The radon-222, an inert gas, appeared to be dissolved in the groundwater of the aquifer after wide diffusion along rock fractures, having been derived from the decay of uranium in underground rocks. The results in this study indicate that groundwater of neutral or weakly alkaline pH, under oxidizing conditions and with a high bicarbonate content is favorable for the dissolution of uranium and uranium complexes such as uranyl or uranyl-carbonate.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.916-927
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• 2010

In general water treatment process, the disinfection process by chlorine is used to prevent water borne disease and microbial regrowth in water distribution system. Because chlorines were reacted with organic matter, carcinogens such as disinfection by-products (DBPs) were produced in drinking water. Therefore, a suitable injection of chlorine is need to decrease DBPs. Rechlorination in water pipelines or reservoirs are recently increased to secure the residual chlorine in the end of water pipelines. EPANET 2.0 developed by the U.S. Environmental Protection Agency (EPA) is used to compute the optimal chlorine injection in water treatment plant and to predict the dosage of rechlorination into water distribution system. The bulk decay constant ($k_{bulk}$) was drawn by bottle test and the wall decay constant ($k_{wall}$) was derived from using systermatic analysis method for water quality modeling in target region. In order to predict water quality based on hydraulic analysis model, residual chlorine concentration was forecasted in water distribution system. The formation of DBPs such as trihalomethanes (THMs) was verified with chlorine dosage in lab-scale test. The bulk decay constant ($k_{bulk}$) was rapidly decreased with increasing temperature in the early time. In the case of 25 degrees celsius, the bulk decay constant ($k_{bulk}$) decreased over half after 25 hours later. In this study, there were able to calculate about optimal rechlorine dosage and select on profitable sites in the network map.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.185-199
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• 1998

Hydrogeochemical and environmental isotope studies were undertaken for various kinds of water samples collected in 1995-1996 from the Bugok geothermal area. Physicochemical data indicate the occurrence of three distinct groups of natural water: Group I ($Na-S0_4$ type water with high temperatures up to $77^{\circ}C$, occurring from the central part of the geothermal area), Group II (warm $Na-HCO_{3}-SO_{4}$ type water, occurring from peripheral sites), Group III ($Ca-HCO_3$ type water, occurring as surface waters and/or shallow cold groundwaters). The Group I waters are further divided into two SUbtypes: Subgroup Ia and Subgroup lb. The general order of increasing degrees of hydrogeochemical evolution (due to the degrees of water-rock interaction) is: Group III$\rightarrow$Group II$\rightarrow$Group I. The Group II and III waters show smaller degrees of interaction with rocks (largely calcite and Na-plagioclase), whereas the Group I waters record the stronger interaction with plagioclase, K-feldspar, mica, chlorite and pyrite. The concentration and sulfur isotope composition of dissolved sulfate appear as a key parameter to understand the origin and evolution of geothermal waters. The sulfate was derived not only from oxidation of sedimentary pyrites in surrounding rocks (especially for the Subgroup Ib waters) but also from magmatic hydrothermal pyrites occurring in restricted fracture channels which extend down to a deep geothermal reservoir (typically for the Subgroup Ia waters). It is shown that the applicability of alkaliion geothermometer calculations for these waters is hampered by several processes (especially the mixing with Mg-rich near-surface waters) that modify the chemical composition. However, the multi-component mineral/water equilibria calculation and available fluid inclusion data indicate that geothermal waters of the Bugok area reach temperatures around $125^{\circ}C$ at deep geothermal reservoir (possibly a cooling pluton). Environmental isotope data (oxygen-18, deuterium and tritium) indicate the origin of all groups of waters from diverse meteoric waters. The Subgroup Ia waters are typically lower in O-H isotope values and tritium content, indicating their derivation from distinct meteoric waters. Combined with tritium isotope data, the Subgroup Ia waters likely represent the older (at least 45 years old) meteoric waters circuated down to the deep geothermal reservoir and record the lesser degrees of mixing with near-surface waters. We propose a model for the genesis and evolution of sulfate-rich geothermal waters.