• Archives of design research
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• v.16 no.4
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• pp.185-196
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• 2003

The demand for an environment-friendly transportation system, equipped with low energy consumption, and low-or zero-pollution has been on the increase since the beginning of the World Trade Organization era. Simultaneously, the consistent growth of high-speed tram technology, combined with market share, has sparked a fierce competition among technologically-advanced countries like France, Germany, and Japan in an effort to keep the lead in high-speed train technology via extensive Research and development(R＆D) expenses. These countries are leaders in the race to implement the next-generation transportation system, build intercontinental rail way networks and export the high-speed train as a major industry commodity. The need to develop our own(Korean) 'high-speed train' technology and its core system technology layouts including original technology serves a few objectives: They boost the national competitive edge; they develop an environmental friendly rail road system that can cope with globalization and minimize the social and economic losses created by the growing traffic-congested delivery costs, environment pollution, and public discomforts. In turn, the 'G7 Project-Development of High Speed Railway Technology' held between 1996 and 2002 for a six-year period was focused on designing a domestic train capable of traveling at a speed of 350km/h combined and led to the actual implementation of engineering and producing the '2000 high-speed train:' This paper summarizes and introduces one of the G7 Projects-specifically, the design segment achievement within the development of train system engineering technology. It is true that the design aspect of the Korean domestic railway system program as a whole was lacking when compared with the advanced railroad countries whose early phase of train design emphasized the design aspect. However, having allowed the active participation of expert designers in the early phase of train design in the current project has led to a new era of domestic train development and the implementation of a way to meet demand flexibly with newly designed trains. The idea of a high-speed train in Korea and its design concept is well-conceived: a faster, more pleasant, and silent based Korean high-speed train that facilitates a new travel culture. A Korean-type of high-speed train is acknowledged by passengers who travel in such trains. The Korean high-speed prototype train has been born, combining aerodynamic air-cushioned design, which is the embodiment of Korean original design of forehead of power car minimized aerodynamic resistance using a curved car body profile, and the improvement of the interior design with ergonomics and the accommodation of the vestibule area through the study of passenger behavior and social culture that is based on the general passenger car.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.350-359
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• 2001

The purpose of this study is to develop theme-based integrated science unit by the interdisciplinary approach and to analyze it's effects on the science achievement and the attitude towards science learning. 'Interaction' and 'Stability' were selected as the integrated themes, and the main concept and subconcept in relation to the themes were extracted from the four areas of science, and the learning contents were constructed in the integrated ways. While the main concept have relevance to subconcept in the interaction, the main concept have little relevance to subconcept in the stability. Therefore, the stability was to fit with middle school integrated science theme, but the interaction was not. The theme-based integrated science units developed was implemented in middle school, and the results are follows. First, the science achievement of group of theme-based integrated science teaching is significantly higher than those of group of traditional teaching. Second, the scores of the test of attitude toward science learning of the group of theme-based integrated science teaching is significantly higher than those of group of traditional teaching. Third, the students' perception of theme-based integrated science teaching was positive. The students have participation, interest, motivation in theme-based integrated science teaching, and students have difficulty in learning theme-based integrated science teaching.

• Analytical Science and Technology
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• v.29 no.2
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• pp.57-64
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• 2016

Many phthalic acid esters (PAEs), including DMP, DEP, DBP, BBP, and DEHP, as well as DEHA are widely used as plasticizers in plastics. An analytical method was developed and used to analyze these compounds at 41 industrial facilities. The coefficient of determination (R²) for each constructed curve was higher than 0.98. The method detection limit (MDL) values were 0.4–0.7 μg/L for PAEs and 0.6 μg/L for DEHA. In addition, the recovery rate was shown to be 77.0–92.3%, while the relative standard deviation was shown to be in the range of 5.8-10.5%. DMP (n = 3), DEP (n = 2), DBP (n = 2), BBP (n = 2), and DEHA (n = 3) were detected in the range of 2.2-11.1% in the influent. DEHP was a predominant compound and was detected at > MDL in both the influent (n = 16, 35.6%) and the effluent (n = 4, 10.0%) at a high removal efficiency (92–100%). The highest levels of residue in industrial wastewater influent were 137.4 μg/L of DEHP at plastic products manufacturing facility, 12.5 μg/L of DEHA at a chemical manufacturing facility, and 14.0 μg/L of DEP at an electronics facility. The highest concentration of effluent was 12.5 μg/L of DEHP at a chemical manufacturing facility, which indicated that the effluent was below the allowable concentration (800 μg/L). Therefore, the levels of PAEs and DEHA that are discharged into nearby streams could not influence the health of the ecosystem.

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.469-479
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• 2001

This study investigated the trends in the number of applicants and mean score and applicants’ responses on the test items of Earth Science in the College Scholastic Ability Test (CSAT) implemented for 3 years (1999-2001). The percentage of applicants of science track were 43.14% in 1995, but reduced through 29.5% in 2001 to 26.92% in 2002 CSAT For elective subject, about 22% of science track students applied to Earth Science II which ranked third to Biology II and Chemistry II. In 1999, test items were developed to have the expected difficulty 40 ${\sim}$ 59% (6 items) to 60 ${\sim}$ 79% (10 items). But in 2001 every 16 items were developed to have difficulty 60 ${\sim}$ 79%, which was caused by the policy of so called ‘easy CSAT’. Thus the mean score of ‘Earth Science II’ was increased from 50.26 in 1999 through 64.47 in 2000, to 67.58 in 2001. Applicants were generally very good at solving test items focusing on process skills only and familar items but poor at solving test items related to the motion of the earth and planets and sea wave, especially items calling two or more concepts. Thus special measures to cope with the decrease in applicants of science track should be provided. And it is recommended to develop test items with wider range of difficulty and to reduce test items calling process skills only. And special consideration should be given to teaching the content area with poor achievement and high actual difficulty compared to the expected.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.1-10
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• 2010

In this study, to study an effective use and improve strength performances of woods and wood-based materials, three-ply hybrid laminated woods which are composed of spruce in the face and three kinds of wood-based boards (MDF, PB, OSB) in the core were manufactured, and the effect of constitution elements used for the core laminae on bending creep performances was investigated. The shape of creep curves showed exponential function plots which the upper right side was increased, and differed among the kinds of wood-based boards used for the core laminae of hybrid laminated wood. The creep deformation perpendicular to the grain of faces of hybrid laminated woods was in order $C_{\perp}$(P) > $C_{\perp}$(M) > $C_{\perp}$(O) with PB, MDF and OSB in the core, respectively. It was found that the creep deformation arranged with OSB in the core had 2 times smaller than those arranged with MDF and PB in the core. By hybrid laminating, the creep deformation of spruce perpendicular to the grain was markedly decreased. On the other hand, the creep deformation parallel to the grain of the faces ($C_{\parallel}$ type) of hybrid laminated woods was in order $C_{\parallel}$(P) > $C_{\parallel}$(O) > $C_{\parallel}$(M) with PB, OSB and MDF in the core. The ratios among three hybrid laminated woods were considerably decreased, especially the difference between $C_{\parallel}$(P) and $C_{\parallel}$(O) hybrid laminated woods arranged with PB and OSB in the core was very small. These values showed 0.108~0.464 times smaller than creep deformation of three wood-based boards and it was found that creep deformation of three wood-based boards was considerably decreased by hybrid laminating. Creep anisotropy of hybrid laminated woods was greater in creep deformation than in initial deformation, whereas it was found that the values was much smaller than that of spruce parallel laminated woods.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.336-344
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• 2015

BACKGROUND: This study was carried out to collect occurrence data on aluminum in 12 type agricultural products and assess dietary exposure risk to the Korean population health for aluminum concentration in agricultural products.METHODS AND RESULTS: Aluminum analysis samples were performed using microwave device and Inductively Coupled Plasma Optical Emission Spectrometer. The LOD(Limit of Detection) for aluminum was 0.851 μg/kg, while the LOQ(Limit of Quantitation) was 2.838 μg/kg and recovery was 97.6% for aluminum. The average levels of aluminum in mg/kg were 0.526 for rice, 0.546 for Korean cabbage, 1.316 for corn, 6.207 for soybean, 0.549 for sweet potato, 0.257 for potato, 6.963 for spinach, 1.213 for carrot, 0.524 for garlic, 0.950 for radish, 1.015 for leek, and 3.511 for Welsh onion. The dietary exposures of aluminum through usual intake were polished rice 89.31 μg/day, Korean cabbage 33.14 μg/day, corn 0.66 μg/day, soybean 3.72 μg/day, sweet potato 6.86 μg/day, potato 4.96 μg/day, spinach 45.96 μg/day, carrot 6.79 μg/day, garlic 2.36 μ g/day, radish 7.32 μg/day, leek 2.23 μg/day and Welsh onion 43.89 μg/day, taking 0.57%, 0.21%, 0.00%, 0.02%, 0.04%, 0.03%, 0.04%, 0.04%, 0.02%, 0.05%, 0.01% and 0.28% of PTWI(2 mg/kg b.w./week), respectively.CONCLUSION: The levels of overall dietary exposure to aluminum for Korean population through intake of agricultural product was far below the recommended JECFA level, indicating of least possibility of risk.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.163-170
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• 1994

The experiment was conducted in 1993 to find out a simple prediction method of weeds and to make the prediction models of weeds in paddy fields. The annuals producing fine seeds were apt to emerge at sampling soil only, on the contrary the perennials and the annuals producing large seeds tended not to emerge at sampling soil due to the miss of seeds at sampling. There was no appropriate regression between a total number of weeds emerged at sampling soil and that of weeds occurred in fields. The important annual weeds occurring in fields were able to predict by the number of weeds emerged at sampling soil, but it was difficult to predict the important perennial weeds. In case of Bidens tripartita producing large seeds and Eleocharis kuroguwai producing large tubers, the prediction coefficients were high as above 1.0, and that of Echinochloa crus-galli and Sagittaria pygmaea were comparatively high as 0.175 and 0.172, respectively. However the coefficients of the other weeds were much low as below 0.08. The prediction models for 9 species were made. The model of six species including E. crus-galli, M. vaginalis, R. indica, B. tripartita, E. triandra and S. pygmaea were linear regression with high significance, however that of 3 species including C. difformis, S. juncoides and E. kuroguwai were curve regression with high significance.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.50-56
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• 1994

This study was investigated for the purposes of securing forage resource using idled rice paddy recently increased in accordance to a current trend of farm products' liberalization and also of presevation of environment by using cattle sluny as liquid manure, which is seriously increasing these days. In this study, mean annual dry matter yield and its seasonal variation with reed canarygrass, and a optimum rate of cattle sluny application were investigated. The results are as follows: 1. According to the conditions of cutting frequencies(3, 4 and 5 cutting per year), mean annual dry matter yield was recorded from 8.9 tons to 10.9 tons per hectare and was the highest at 3 cutting frequency. 2. The use of cattle sluny with the levels of between 300 and 360 kg N per hectare showed a significantly higher mean annual dry matter yield than that of the control (non-fertilization). 3. The treatments with 3 and 4 cutting frequencies(90 kg Nhdyear, 120 kg Nhdyear) recorded higher dry matter yields than the control of the former level by 1.23 tons and 2.34 tons respectively and in the treatment of 5 cutting frequency, the second level with cattle sluny of 300 kg Nhdyear showed an increased dry matter yield of 2.11 tons compared to the former level(l50 kg Nhdyear). With regards to nitrogen efficiency, one kg of nitrogen is applied to 13.7, 19.4 and 14.1 kg of dry matter yields in the conditions of 3, 4 and 5 cutting frequencies respectively. 4. In view of seasonal variance of annual dry matter yield, the second cut in 3 cutting frequency, the third cut in 4 cutting frequency and the third in 5 cutting frequency showed the highest ratio as 42, 37 and 32% respectively compared to the total. 5. Under the conditions of this study, the 'Input-Output curve' from 5 cutting frequency was the closest to sigmaformed process(i=0.9993) of various cutting frequencies, and the maximum marginal yield in the treatment was obtained at the level of 250 kg Nha with cattle sluny. The economic level of cattle sluny was between 371.0 and 402.2 kg N and the highest dry matter yield was obtained at 489.3 kg Mdyear in the same treatment

• Nuclear Medicine and Molecular Imaging
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• v.41 no.6
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• pp.553-560
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• 2007

Purpose: We evaluated the standard uptake value (SUV) of F-18 FDG at PET/CT for differentiation of benign from malignant tumor in primary musculoskeletal tumors. Materials and Methods: Forty-six tumors (11 benign and 12 malignant soft tissue tumors, 9 benign and 14 malignant bone tumors) were examined with F-18 FDG PET/CT (Discovery ST, GE) prior to tissue diagnosis. The maxSUV(maximum value of SUV) were calculated and compared between benign and malignant lesions. The lesion analysis was based on the transverse whole body image. The maxSUV with cutoff of 4.1 was used in distinguishing benign from malignant soft tissue tumor and 3.05 was used in bone tumor by ROC curve. Results: There was a statistically significant difference in maxSUV between benign (n=11; maxSUV $3.4{\pm}3.2$) and malignant (n=12; maxSUV $14.8{\pm}12.2$) lesions in soft tissue tumor (p=0.001). Between benign bone tumor (n=9; maxSUV $5.4{\pm}4.0$) and malignant bone tumor (n=14; maxSUV $7.3{\pm}3.2$), there was not a significant difference in maxSUV. The sensitivity and specificity for differentiating malignant from benign soft tissue tumor was 83% and 91%, respectively. There were four false positive malignant bone tumor cases to include fibrous dysplasia, Langerhans-cell histiocytosis (n=2) and osteoid osteoma. Also, one false positive case of malignant soft tissue tumor was nodular fasciitis. Conclusion: The maxSUV was useful for differentiation of benign from malignant lesion in primary soft tissue tumors. In bone tumor, the low maxSUV correlated well with benign lesions but high maxSUV did not always mean malignancy.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.253-263
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• 2002

Purpose : In order to understand in vivo radiation damage modifying of bFGF on jejunal mucosa, bone marrow and the effect of bFGF on the growth of transplanted mouse sarcoma 180 tumor in mice. Materials and Methods : Mice were treated with $6\;{\mu}g$ of bFGF at 24 hours and 4 hours before exposing to 600 cGy, 800 cGy and 1,000 cGy total body irradiation (TBI), and then exposed to 3,000 cGy local radiation therapy on the tumor bearing thigh. Survival and tumor growth curve were plotted in radiation alone group and combined group of bFGF and irradiation (RT). Histologic examination was performed in another experimental group. Experimental groups consisted of normal control, tumor control, RT (radiation therapy) alone, $6\;{\mu}g$ bFGF alone, combined group of $3\;{\mu}g$ bFGF and irradiation (RT), combined group of $6\;{\mu}g$ bFGF and irradiation (RT). Histologic examination was peformed with H-E staining in marrow, jejunal mucosa, lung and sarcoma 180 bearing tumor. Radiation induced apoptosis was determined in each group with the DNA terminal transferase nick-end labeling method ($ApopTag^{\circledR}$ S7100-kit, Intergen Co.) Results : The results were as follows 1) $6\;{\mu}g$ bFGF given before TBI significantly improved the survival of lethally irradiated mice. bFGF would protect against lethal bone marrow syndrome. 2) $6\;{\mu}g$ bFGF treated group showed a significant higher crypt depth and microvilli length than RT alone group (p<0.05). 3) The bone marrow of bFGF treated group showed less hypocellularity than radiation alone group on day 7 and 14 after TBI (p<0.05), and this protective effect was more evident in $6\;{\mu}g$ bFGF treated group than that of $3\;{\mu}g$ bFGF treated group. 4) bFGF protected against early radiation induced apoptosis in intestinal crypt cell but might have had no antiapoptotic effect in bone marrow stem cell and pulmonary endothelial cells. 5) There was no significant differences in tumor growth rate between tumor control and bFGF alone groups (p>0.05). 6) There were no significant differences in histopathologic findings of lung and mouse sarcoma 180 tumor between radiation alone group and bFGF treated group. Conclusions : Our results suggest that bFGF protects small bowel and bone marrow from acute radiation damage without promoting the inoculated tumor growth in C3H mice. Improved recovery of early responding normal tissue and reduced number of radiation induced apoptosis may be possible mechanism of radioprotective effect of bFGF.