• The Korean Journal of Ecology
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• v.17 no.4
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• pp.485-499
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• 1994

This study was focused on the effect of the altitude on the geographical variations of germination characteristics in the populations of Plantago asiatica L. distribute in Mt. Chiri. There was a significant difference among the 14 groups in the phenological pattern in relation to altitudes. When the altitude becomes higher, the thermal time which was required for 10 to 80% germination rate showed higher and wider distribution. On the other hand, the germination response of increasing temperature (IT) and secreasing temperature (DT) regime was classified into 3 group. The first group was the spering germination type. This group showed that the IT regime hadhigher germination rate than that of the DT regime, and was distributed in Macheon(300m) and Packmudong (500m). The second was the spring-fall germination type which was distributed in Hadong (900m) and Saemt대 (1100m). This group also showed higher germination rate in the IT regime, but the difference of the germination rate between IT and DT regime was less than that in the first group (the spring type). The third group was the early fall germination type which was found in the Nogodan (1507m), Changetomok (1750m) and Cheonwangbong (1915m). The germination rate of this group showed almost 100% similarity between IT and DT regime. These data suggested that the geographical varations of germination characteristics within species was an important ecological strategy for the survival from severe environmental conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.3
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• pp.187-194
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• 2020

In this study, computational analyses are carried out to investigate the interference flows and the aerodynamic characteristics of a hit-to-kill intercepter due to lateral jets at medium altitude. In addition, the analyses are performed for air and multi-species gas used in the side jet. The results indicate that the position of the barrel shock are shifted upstream and the structure of the shock wave are changed for the multi-species jet when compared to the air jet. As a result, the high pressure region with multi-species jet moves forward and the pitching moment is higher under the same flow condition. Moreover, the inclusion of high temperature effects makes drastic changes in pressure distribution. The jet width is much bigger, and the jet diffuses over wider range in medium altitude than in low altitude, because of the low density of the freestream.

• Korean Journal of Environment and Ecology
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• v.3 no.1
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• pp.51-69
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• 1989

To investigate edge vegetation structure and edge species in Kaya Mountain National Park, field survey was executed from July to August, 1989 and the result are as follows. Cantilevered and advancing types of edge vegetation were observed on site, The relative importance values of major species were changed along distance from edge to forest interior and were seemed to be affected by aspect, soil moisture and present tree layer vegetation. Especially, light-oriented species were observed as a codominant species under pine tree canopy due to selective allelopathy effect and thin canopy. Ecological indices according to the distance from edge to forest interior did not show regular pattern, but edge depth was estimated as 15-20m, approximately, Dominant species of edge seemed to be affected by soil moisture rather than altitude and aspect, but floristic similarities seemed to be affected by altitude. Frequency classes of edge species were different by aspect, altitude and physiogra-phical location. Lespedeza maximowiczii, Weigela subsessilis and Fraxinus rhynchophylla showed high frequency class in all environment conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.153-160
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• 1992

This experiment was conducted to investigate the adaptability of legume in different legume-grass mixtures according to altitude(600, 800, lOOOm a.s.1.) in the alpine area. The experimental plot was allocated as a split plot design with three replications. The main plots were sowing season(spring and fall) and subplots legume-grass mixture(alfa1fa-grass, red clover-grass and white clover-grass mixture). The results obtained are summarized as follows: 1. At 600m, in case of sowing alfalfa, red clover and white clover in fall. each legume of legume-grass mixtures was consistuted about 30% without between-year variation and then all legumes at fall sowing could grow. 2. At 800m, in case of sowing white clover in spring this species was consistuted about 14.7 % at the last cutting without severe between-year variation. 3. At 1000m, only white clover sown in spring like at 800m was somewhat maintained without severe between-year variation. 4. Percentage and DM yield of legume considerably decreased with the rise of altitude and alfalfa couldn't grow more than 800m.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.11-19
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• 2021

Contrails are line-shaped clouds formed by the condensation of water vapor from the interaction of exhaust gas from aircraft engines and the high-altitude atmosphere. Contrails are known to aggravate global warming by creating a greenhouse effect by absorbing or reflecting radiation emitted from the Earth. In this study, development of a model that can quantitatively predict the contrail occurrence was conducted for the reduction of contrail, which is likely to form an aircraft certification category in the future. Based on prior research results, a model that can predict the occurrence of contrail between Tokyo and Qingdao was developed, in addition to proposing improved flight altitude that can minimize the occurrence of contrail.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.14-18
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• 2007

The ground effect on tilt-rotor UAV is analyzed by simulating the hovering UAV for various altitudes. Ground effect increases pressure beneath the UAV body and generates additional lifting force. The ground effect diminishes at altitude 3m and hovering UAV generates constant lifting force above 3m.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.203-212
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• 2002

This study was conducted to remove the urban heat island effects embedded in the interpolated surfaces of daily minimum temperature in the Korean Peninsula. Fifty six standard weather stations are usually used to generate the gridded temperature surface in South Korea. Since most of the weather stations are located in heavily populated and urbanized areas, the observed minimum temperature data are contaminated with the so-called urban heat island effect. Without an appropriate correction, temperature estimates over rural area or forests might deviate significantly from the actual values. We simulated the spatial pattern of population distribution within any single population reporting district (city or country) by allocating the reported population to the "urban" pixels of a land cover map with a 30 by 30 m spacing. By using this "digital population model" (DPM), we can simulate the horizontal diffusion of urban effect, which is not possible with the spatially discontinuous nature of the population statistics fer each city or county. The temperature estimation error from the existing interpolation scheme, which considers both the distance and the altitude effects, was regressed to the DPMs smoothed at 5 different scales, i.e., the radial extent of 0.5, 1.5, 2.5, 3.5 and 5.0 km. Optimum regression models were used in conjunction with the distance-altitude interpolation to predict monthly normals of daily minimum temperature in South Korea far 1971-2000 period. Cross validation showed around 50% reduction in terms of RMSE and MAE over all months compared with those by the conventional method.conventional method.

• Economic and Environmental Geology
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• v.36 no.5
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• pp.329-338
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• 2003

The purpose of this study is to identify the temporal and spatial variation of stable isotopic compositions of surface waters and shallow ground waters at a local watershed(100$Km^2$) near the Muju area. For oxygen and hydrogen isotope analysis, water samples were collected from 19-22 sites during August, October 2001, through April 2002. Seasonal variation in the isotopic compositions of surface waters was clearly shown. However, the degree of such isotopic variation was highly attenuated in shallow ground waters because of mixing with preexisting ground waters. Isotope values of surface waters and ground waters were very similar in each season, indicating that precipitation/ground water/surface water interactions were very active and continuous in the watershed. Stable isotopic ratios of surface waters in the study area were lighter than those of the downstream reach of Geum River on south, indicating “latitude effect”. Both “altitude effect” and “amount effect” were also shown in the stable isotopic ratios of surface waters in the study area as well as seasonal variation of stable isotopes.

• Hwankyungkyoyuk
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• v.22 no.3
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• pp.83-96
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• 2009

This article extracted feasible elements for an environmental education program from the 'Intelligent Life', an integrated subject of the 7th elementary school curriculum, and designed a program for second graders in the elementary school and applied it to them in order to examine how the students' environmental altitudes changed. In the controlled class, the instruction followed the lessons specified in the 7th national curriculum faithfully while for the experimental class 1, only the inquiry activity-based environmental education program was applied. Moreover, in experimental class 2, the inquiry activity-based environmental education program was implemented and wrap-up activity was performed as well with the products. To verify the program, questionnaires on the change of environmental altitudes were distributed and analyzed total three times in the pretest, posttest 1(right after the program), and posttest 2(30 days after the program). T-test was carried out with the SPSS 12 program to verify the effect of the applied program. To make up for the quantitative analysis, qualitative analysis was also conducted. The followings show the results gained after the program was implemented. First, This program showed a significant difference(p<.05) in the students' formation of environmental altitudes. Second, it was verified that the inquiry activity-based environmental education class that reorganized the second grade elementary students' 'Intelligent Life' subject had a more positive effect in the cultivation of environmental altitude than the class that followed the present curriculum as it was. It will be necessary to perform follow-up researches on the relativity between curricula for kindergarteners and lower grade elementary school students.

• Journal of the Korea Concrete Institute
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• v.29 no.2
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• pp.169-177
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• 2017

Rather than causing damage from heat, blast, and radiation of a regular nuclear weapon, recently, it is predicted that North Korea has been inventing high altitude electromagnetic pulse (HEMP) missile in order to incapacitate electronic equipment. HEMP shielding facility is used for military purpose today. Despite the electromagnetic shielding effects from high quality compression plates, problems may include such as the possibility of electromagnetic influx resulting in the welding of the compression plates, and difficulties and high cost of construction. Therefore, in this study, a high electrical conducting material was added to the concrete experimental subject to ensure the shielding effect through electromagnetic waves to for the concrete structure, instead of building a shielding facility separately for the structure. Also, among the experimental subjects, 100 ${\mu}m$ of Iron-Aluminum alloy metal spraying coat was applied to two types with the highest shielding effect, and to two types with the lowest shielding effect. The result of the experiment indicates that experimental subjects added with a high electrical conductivity material did not meet the minimum shielding criteria of MIL-STD-118-125-1 standard, but all the experimental material applied to the metal spraying coating satisfied the minimum shielding criteria. In conclusion, it is considered that 100 µm of Iron-Aluminum alloy metal spraying coat contains high efficiency in the HEMP shielding.