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Comparative Studies on Absorbed Dose by Geant4-based Simulation Using DICOM File and Gafchromic EBT2 Film (DICOM 파일을 사용한 Geant4 시뮬레이션과 Gafchromic EBT2 필름에 의한 인체 내 흡수선량 비교 연구)

  • Mo, Eun-Hui;Lee, Sang-Ho;Ahn, Sung-Hwan;Kim, Chong-Yeal
    • Progress in Medical Physics
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    • v.24 no.1
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    • pp.48-53
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    • 2013
  • Monte Carlo method has been known as the most accurate method for calculating absorbed dose in the human body, and an anthropomorphic phantom has been mainly used as a method of simulating internal organs for using such a calculation method. However, various efforts are made to extract data on several internal organs in the human body directly from CT DICOM files in recent Monte Carlo calculation using Geant4 code and to use by converting them into the geometry necessary for simulation. Such a function makes it possible to calculate the internal absorbed dose accurately while duplicating the actual human anatomical structure. Thus, this study calculated the absorbed dose in the human body by using Geant4 associating with DICOM files, and aimed to confirm the usefulness by compare the result with the measured dose using a Gafchromic EBT2 film. This study compared the dose calculated using simulation and the measured dose in beam central axis using the EBT2 film. The results showed that the range of difference was an average of 3.75% except for a build-up region, in which the dose rapidly changed from skin surface to the depth of maximum dose. In addition, this study made it easy to confirm the target absorbed dose by internal organ and organ through the output of the calculated value of dose by CT slice and the dose value of each voxel in each slice. Thus, the method that outputs dose value by slice and voxel through the use of CT DICOM, which is actual image data of human body, instead of the anthropomorphic phantom enables accurate dose calculations of various regions. Therefore, it is considered that it will be useful for dose calculation of radiotherapy planning system in the future. Moreover, it is applicable for currently-used several energy ranges in current use, so it is considered that it will be effectively used in order to check the radiation absorbed dose in the human body.

Improved Device Performance Due to AlxGa1-xAs Barrier in Sub-monolayer Quantum Dot Infrared Photodetector

  • Han, Im Sik;Byun, Young-Jin;Lee, Yong Seok;Noh, Sam Kyu;Kang, Sangwoo;Kim, Jong Su;Kim, Jun Oh;Krishna, Sanjay;Ku, Zahyun;Urbas, Augustine;Lee, Sang Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.298-298
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    • 2014
  • Quantum dot infrared photodetectors (QDIPs) based on Stranski-Krastanov (SK) quantum dots (QDs) have been widely explored for improved device performance using various designs of heterostructures. However, one of the biggest limitations of this approach is the "pancake" shape of the dot, with a base of 20-30 nm and a height of 4-6 nm. This limits the 3D confinement in the quantum dot and reduces the ratio of normal incidence absorption to the off-axis absorption. One of the alternative growth modes to the formation of SK QDs is a sub-monolayer (SML) deposition technique, which can achieve a much higher density, smaller size, better uniformity, and has no wetting layer as compared to the SK growth mode. Due to the advantages of SML-QDs, the SML-QDIP design has attractive features such as increased normal incidence absorption, strong in-plane quantum confinement, and narrow spectral wavelength detection as compared with SK-DWELL. In this study, we report on the improved device performance of InAs/InGaAs SML-QDIP with different composition of $Al_xGa1-_xAs$ barrier. Two SML-QDIPs (x=0.07 for sample A and x=0.20 for sample B) are grown with the 4 stacks 0.3 ML InAs. It is investigated that sample A with a confinement-enhanced (CE) $Al_{0.22}Ga_{0.78}As$ barrier had a single peak at $7.8{\mu}m$ at 77 K. However, sample B with an $Al_{0.20}Ga_{0.80}As$ barrier had three peaks at (${\sim}3.5{\mu}m$, ${\sim}5{\mu}m$, ${\sim}7{\mu}m$) due to various quantum confined transitions. The measured peak responsivities (see Fig) are ~0.45 A/W (sample A, at $7.8{\mu}m$, $V_b=-0.4V$ bias) and ~1.3 A/W (sample B, at $7{\mu}m$, $V_b=-1.5V$ bias). At 77 K, sample A and B had a detectivity of $1.2{\times}10^{11}cm.Hz^{1/2}/W$ ($V_b=-0.4V$ bias) and $5.4{\times}10^{11}cm.Hz^{1/2}/W$ ($V_b=-1.5V$ bias), respectively. It is obvious that the higher $D^*$ of sample B (than sample A) is mainly due to the low dark current and high responsivity.

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Alexithymia in Major Depressive Disorder and Subclinical Depression (주요 우울장애와 준임상적 우울증에서의 감정표현불능증)

  • Kim, Seog-Ju;Yu, Seung-Hee;Kim, Seong-Youn;Kim, Dong-Wook;Cho, In-Hee;Cho, Seong-Jin
    • Korean Journal of Psychosomatic Medicine
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    • v.15 no.2
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    • pp.100-106
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    • 2007
  • Objectives : The objective of the present study was to investigate alexithymia in major depressive disorder(MDD) and subclinical depression(SCD). Methods : Three hundred eighty-six community-dwelling adults(238 females and 148 males, age 19-79; mean age $43.0{\pm}13.9$) were recruited. Structured clinical Interview for DSM-IV(SCID) was conducted for the diagnosis of MDD or other Axis I psychiatric disorders. The Center for Epidemiological Studies for Depression Scale(CES-D) and the Totonto Alexithymia Scale(TAS) were administered to assess depressive symptom and alexithymia, respectively. Among subjects without MDD, those who had minor depressive disorder on the SCID or high scores(i.e. over 16) on the CES-D were defined as subjects with SCD. TAS total score and factor I, II, III scores of TAS in MDD, SCD, and non-depressive controls were compared. Results : Among 386 subjects, 38 subjects(9.8%) were diagnosed as MDD by DSM-IV criteria, while 57 subjects(14.8%) were classified into SCD group. There were significant differences between 3 groups(MDD, SCD and non-depressive controls) in total score($F_{2,383}=14.0$, p<0.01), factor I(difficulty in identifying feeling)($F_{2,383}=23.4$, p<0.01) and factor II(difficulty in describing feeling)($F_{2,383}=7.8$, p<0.01), but not factor III(external oriented thinking)($F_{2,383}=1.8$, p=0.16) of TAS. In post-hoc analysis, both MDD subjects and SCD subjects had higher scores in TAS total, factor I and factor II, compared to non-depressive controls(all p<0.01). In contrast, there were no significant differences between MDD subjects and SCD subjects in any TAS factor. Conclusion : In this study, both MDD subjects and SCD subjects were more alexithymic than non-depressive control subjects. These findings suggest that SCD, as well as MDD, is also related to alexithymia.

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A Case Study of Geometrical Fracture Model for Groundwater Well Placement, Eastern Munsan, Gyeonggido, Korea (지하수개발을 위한 단열모델 연구사례(경기도 문산 동쪽지역))

  • Choi Sung-Ja;Chwae Uee-Chan;Kim Se-Kon;Park Jun-Beom;Sung Ki-Sung;Sung Ik-Whan
    • Economic and Environmental Geology
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    • v.39 no.2 s.177
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    • pp.163-171
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    • 2006
  • This study is the case of groundwater development based on the geometrical fracture model of target area established only through geological fracture mapping technique. A fracture mapping of $9km^2$, eastern Munsan, has been conducted to determine geological and hydrological factors for new water well placement in the Gyeonggi gneiss complex. Geophysical exploration was not applicable because of small restricted area and dense underground utilities at the site. Form line mapping on the basis of foliation orientation and rock type revealed a synform of NS fold axis bearing to the south. An EW geological cross-section passed through the site area shows a F2 synform as a double-wall ice cream spoon shape. Three regional faults of $N20^{\circ}E,\;N30^{\circ}W$, and NS have been dragged into the site to help understand extensional fault paths. The $N20^{\circ}E$ fault with dextral sense is geometrically interpreted as a western fault of two flexural conjugate type-P shear faults in the F2 synformal fold. The NE cross-section reveals that a possible groundwater belt in the western limb of super-posed fold area is formed as a trigonal prism within 100 m depth of the intersectional space between the $N20^{\circ}E$ fault plane and the weakly sheared plane of transposed foliation. Another possible fault for water resource strikes $N40^{\circ}E$. Recommended sites for new water well placement are along the $N20^{\circ}E\;and\;N40^{\circ}E$ faults. As a result of fracture mapping, 145 ton/day of water can be produced at one well along the $N20^{\circ}E$ fault line. Exploration of groundwater in the area is succeeded only using with geological fracture mapping and interpretation of geological cross-section, without any geophysical survey. Intersection of fault generated with the F2 synformal fold and foliation supply space of groundwater reserver.

A Correlation between the Fractionation of Heavy Metals in the Paddy Soil of the Mangyeong River Basin and their Uptake by Rice Plants Grown on it (만경강 유역 논 토양 중 중금속 형태분류와 수도체의 흡수량과의 관계)

  • Kim, Seong-Jo;Baek, Seung-Hwa;Moon, Kwang-Hyun
    • Korean Journal of Environmental Agriculture
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    • v.15 no.3
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    • pp.372-382
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    • 1996
  • In order to elucidate the relationship between the mobility of heavy metals in soil and their uptake by plants, the soil samples collected from the Mangyeong River area were analyzed for the contents and existing forms of the heavy metals and the correlation between the contents of heavy metals in the soil and those in various parts of rice plants therefrom. The soil samples were collectes from ten sites in the paddy fields in 1982 and 1990, respectively, and the analysis on heavy metals including Cd, Zn, Cu and Pb was performed. The results are as follows: Total contents of heavy metals in the samples of 1990 were higher than those of 1982. The extent of increase was that Cd, Zn, Cu and Pb were 3, 29, 59 and 8% in top soil and 8, 50, 91 and 8% in sub-soil, respectively. The order of increasing ratio was Cu > Zn > Pb > Cd and the variation of Cd content by sequentially different extraction was organically bound > dilute acid-extractable=Fe-Mn oxide bound > exchangeable > residual fractions and the content of Cd with organically bound was $46.62{\sim}48.08$ and $41.18{\sim}50.18%$ of total Cd in top and sub-soil, respectively. The ratios of immobile heavy metals, Cd, Pb, Cu and Zn, bound within an oxide or silicate matrix of Fe-Mn oxide in top-soil were 21.25, 35.98, 74.18 and 82.12%, respectively, and consequently their mobile ratios of exchangeable, dilute acid-extractable and organically bound were more than 17.88%. Those of mobile Cd, Pb, Cu and Zn were 78.25, 64.02, 25.82 and 17.88%, respectively. Except for Pb a correlation between the contents of Cd, Zn, and Cu of exchangeable and dilute acid-extractable in top-soil and those in leaf blade, stem and panicle axis was significant, but was not significant in sub-soil.

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A Study on Construction of Region-Based Cartoon Creation & Production Center (지역 중심의 만화 창· 제작센터 구축에 대한 연구)

  • Lee, Jin-hee;Kim, Byoung-Soo
    • Cartoon and Animation Studies
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    • s.45
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    • pp.147-175
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    • 2016
  • This thesis aims to research ways for the regional balanced development of cartoon creation & production environment being centered in metropolitan area in Korean cartoon industry which has rapidly changed since 2013. As a cartoon can not only be produced with relative lower production cost comparing to those of other cultural contents industries, but also can be produced only if the minimal requirements for cartoon production is prepared, so the cartoon is a field that the decentralization can be accomplished very easily. Currently, most cartoon-relevant companies and cartoon promotion institutions are located in Seoul an Bucheon, etc. However, cartoon artists live nationwide, and even cartoon artists producing their works abroad are reached to a significant number. In some regions like Daejeon, Busan, Suncheon and Gyeongbuk (Gyeongsangbuk-do), there have been appeared full-scale movement to construct regional cartoon creation & production centers since 2015. This thesis aimed to investigate each region's movement to construct cartoon creation & production center with oversea cases, and to check how such movement could be balanced and harmonized with each region's unique features. First of all, this thesis analyzed the status quo of government's policy nurturing the cartoon industry. Korean government's cartoon-promotion policy around the axis of the Cartoon Industry's Mid.Long-Term Development Plan has been developed around the Korea Creative Content Agency and the Korea Manwha(cartoon) Contents Agency in Bucheon, but as the webtoon industry has rapidly grown up, the necessity for building a cartoon promotion institution in each region has been raised since 2015. With the establishment of 4th Cartoon Industry Mid.Long-Term Development Plan to be executed from 2019, it seems that full-scaled support framework for cartoon regional balanced development should be occupied. For the case of foreign countries, cartoon promotion institutions and relevant events have been developed around regions from early times like San-Diego, USA(Comicon), Angouleme, France(National Image Center), Kyoto (Cartoon Museum), Sakaiminato(Misuki Sigeru Road), Japan gave a lot of implications. In the section of conclusion, this study aimed to suggest the importance of and necessity for establishing a cartoon creation & production center in each region appropriately for the region's identity and characteristics with specific plans. Based on that, this thesis aimed to suggest a vision for cartoon & webtoon industry that regional creation & production system can be settled almost only in the cultural contents industry.

Analysis of Mistakes in Photosynthesis Unit in Biology II Textbooks and Survey of Biology Teachers' Recognition on them (생물 II 교과서 광합성 단원의 오류 분석 및 생물 교사의 오류 인지 조사)

  • Park, Hae-Kyung;Yoon, Ki-Soon;Kwon, Duck-Kee
    • Journal of Science Education
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    • v.32 no.1
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    • pp.33-46
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    • 2008
  • The purpose of this study was to know whether or not any wrongful description or simple errors were in photosynthesis unit of Biology II textbook under 7th national curriculum and if so, to know whether or not high school teachers recognized and corrected properly the mistakes. The mistakes in photosynthesis unit of text books were determined by the comparison with several reference books and through examination by three plant physiologists in 8 different Biology II textbooks. After the mistakes were analysed, the survey using contents of textbook containing the mistakes was conducted on high school teachers teaching Biology II. As a result, 48 mistakes were determined in 13 subjects. As many as four mistakes were found even in one subject in a certain textbook and a same mistake was found repeatedly in several textbooks. The survey result showed that the teachers who pointed exactly the mistakes out corrected properly, however, the percentage of these ones out of 35 teachers replied to survey was less than 50%. The ratios of correction out of total number of responses were high in question #6 (43%), #4-3 (40%), and #1-2 (32%) which were containing a simple mistake in graph, a wrong word and a wrong picture, respectively. But, no one pointed out and made correction in question #5-1 and #5-2 which were containing Z scheme of light reaction without the legend of vertical axis that should be explained as electron energy or standard reduction potential. The result indicates the possibility that the mistakes in photosynthesis unit of Biology II textbook can be corrected and teached properly by teachers may be low. In order to reduce the possibility that students may have misconceptions about photosynthesis, the list of print's errors should be provided to the teachers and/or the training program and/or workshop for in-service high school biology teachers was recommended.

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Vertical Distribution of Vascular Plant Species along an Elevational Gradients in the Gyebangsan Area of Odaesan National Park (오대산국립공원 계방산지구 관속식물의 고도별 수직분포)

  • An, Ji-Hong;Park, Hwan-Jun;Nam, Gi-Heum;Lee, Byoung-Yoon;Park, Chan-Ho;Kim, Jung-Hyun
    • Korean Journal of Ecology and Environment
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    • v.50 no.4
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    • pp.381-402
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    • 2017
  • In order to investigate distribution of vascular plants along elevational gradient in the Nodong valley of Gyebangsan, vascular plants of eight sections with 100-meter-high were surveyed from the Auto-camping site (800 m) to the top of a mountain (1,577 m). There were a total of 382 taxa: 89 families, 234 genera, 339 species, 7 subspecies, 34 varieties, and 2 forms. As a result of analyzing the pattern of species richness, it showed a reversed hump-shaped with minimum richness at mid-high elevation. As a result of analyzing habitat affinity types, the proportion of forest species increased with increasing elevation. But, the ruderal species decreased with increasing elevation, and then increased at the top of a mountain. As for the proportion of life forms, the annual herbs gradually decreased with increasing elevation, but it did not appear between 1,300 m and 1,500 m and then increased at the top of a mountain. The trees gradually increased with elevation and decreased from 1,300~1,400 m. The vascular plants divided into four groups by using DCA. The arrangement of each stands was arranged in order from right to left on the I axis according to the elevation. The distribution of vascular plants is determined by their own optimal ranges of vegetation. Also, rise in temperature due to climate change affects the distribution of vascular plants, composition, and diversity. Therefore, continuous monitoring is necessary to confirm ecological and environmental characteristics of vegetation, distribution ranges, changes of habitat. Furthermore, plans for conservation and management based on these data should be prepared according to climate change.

Evaluations of Ecological Habitat, Chemical Water Quality, and Fish Multi-Metric Model in Hyeongsan River Watershed (형산강 수계의 생태 서식지, 화학적 수질 및 어류의 다변수모델 평가)

  • Kim, Yu-Pyo;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.43 no.2
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    • pp.279-287
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    • 2010
  • This study was to evaluate ecological conditions of Hyeongsan River watershed from April to September 2009. The ecological health assessments was based on Qualitative Habitat Evaluation Index (QHEI), water chemistry during 2000~2009, and the fish multi-metric model, Index of Biological Integrity (IBI). For the study, the models of IBI and QHEI were modified as 8 and 11 metric attributes, respectively. Values of IBI averaged 25.4 (n=6), which is judged as a "fair" condition (C) after the criteria of Barbour et al. (1999). The distinct spatial variation was found in the IBI. Physical habitat health, based on the values of QHEI, varied from 76 in the downriver (H6) to 150.5 in the headwater (H1) and was evidently more disturbed in the downriver reach. Values of BOD and COD averaged 2.4 $mgL^{-1}$ (range: 0.3~13.8 $mgL^{-1}$) and 4.3 $mgL^{-1}$ (scope: 0.6~12.8 $mgL^{-1}$), respectively during the study period. Total nitrogen (TN) and total phosphorus (TP) averaged 3.0 $mgL^{-1}$ and 103.5 ${\mu}gL^{-1}$, respectively, indicating a severe eutrophication, and the nutrients increased more in the downriver than the headwater. Overall, physical, chemical and IBI parameters showed a typical downriver degradation along main axis of the river from the headwater-to-the downriver. This was mainly attributed to livestock waste and residential influences along with industrial discharge from the urban region.

Tectonic Movement in the Korean Peninsula (I): The Spatial Distribution of Tectonic Movement Identified by Terrain Analyses (한반도의 지반운동 ( I ): DEM 분석을 통한 지반운동의 공간적 분포 규명)

  • Park, Soo-Jin
    • Journal of the Korean Geographical Society
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    • v.42 no.3 s.120
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    • pp.368-387
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    • 2007
  • In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.