• Title/Summary/Keyword: Natural Phenomena

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Design Expressions in Forms of Contemporary Hair Style in Collections between 1995${\sim}$2004

  • Lee, Su-In;Park, Kil-Soon
    • The International Journal of Costume Culture
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    • v.9 no.2
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    • pp.83-93
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    • 2006
  • This study aims to analyze the hair styles featured in the collections from S/S season of 1995 to F/W season of 2004 both qualitatively and quantitatively by using content-analytical methods. This study was able to form a classifying system that divides hair styles into those artificial and those natural through systematic and scientific research. The resulting system, in turn, broadened the basis for understanding modern fashion and hair style expressions. In addition, by analyzing design-related characteristics, certain expressive techniques employed, and trends in detail, this study contributed to establishing the hair styles, which form part of socio-cultural phenomena, as an academic subject.

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An Ethnorgraphic Study on the Elementary Science Classes of the 5th grade Students (초등학교 5학년 자연과 실험 수업에 대한 문화기술적 연구)

  • 최옥자;김효남;백성혜
    • Journal of Korean Elementary Science Education
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    • v.18 no.2
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    • pp.35-46
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    • 1999
  • The most of elementary school science textbook contents are composed of observation and experiment activities. When students study natural phenomena, observation and experiment are st rongly emphasized to improve understanding of scientific concepts and inquiry abilities. The purpose of this study is deep understanding about experimental science classes. This ethnographic study is conducted by observations of experimental science classes in natural setting and interviews of teachers, students of the 5th grade. The conclusions of this study are as follows: First, the general process of the elementary science experimental classes is 'identifying learning purposes -1 planning experiments -1 predicting the results -1 experimenting-t summarizing the results.' The experiments are conducted by group activities and the teachers conceived that the me st difficult step considered by students is 'planning experiments'. Second, students like hands-on activities, but they feel difficulty on less guided experiments. Students perform results oriented-activities. Third, in group activities, students prefer to work with the same gender or collaborative peers.

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The Efficient ICT Devices Utilization Method using Disaster Security Communication Network (재난안전통신망을 이용한 효율적인 ICT 기기 활용 방안)

  • Hong, Sung-Hwa;Lee, Seong-Real
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.10a
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    • pp.474-476
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    • 2018
  • Natural disasters destroy decades of human effort and investments, thereby placing new demands on society for reconstruction and rehabilitation. In most case, the natural phenomena triggering the disasters are beyond human control. In order to solve the problems that the information resources can not be shared among disaster management sectors and their work is hard to be coordinated in city, an idea of application of ubiquitous sense network and ICT technology to model the architecture of the disaster prevention system based on the analysis of characteristics of disasters.

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A Study on Buoyancy Effects in Double-Diffusive Convecting System (이중확산대류계에서의 부력효과에 관한 연구(Ⅰ)- 실험적 연구 -)

  • Kim, Yang-Hun;Hyun, Myung-Taek;Kim, Min-Chan
    • Journal of Ocean Engineering and Technology
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    • v.13 no.1 s.31
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    • pp.121-129
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    • 1999
  • Double-diffusive convection with verical temperature and concentration gradients in thermally stratified fluids has been investigated experimentally using an electrochemical technique. Cupric sulfuric-sulffuric acid solution confined between two horizontal copper electrodes was used. The change of thermal and solutal buoyance has no influence on the range of voltage for the limiting current. Due to Soret effect, the onset time of natural convection is delayed as the stabilizing thermal buoyancy decreases. Also it is found that the shrinkage of the unstabilizing solutal buoyancy makes the onset of natural convection retard. Multi-layered convective phenomena do not appear because cupric sulfate-sulfuric acid solution is thermally stratified, and heat diffuses faster than cupric sulfate solfate solution.

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Two-photon resonance condition in Three level Atomic System (3준위 원자계에서 2광자 공진 조건)

  • Park, Jong-Dae;Cho, Chang-Ho
    • The Journal of Natural Sciences
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    • v.12 no.1
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    • pp.23-30
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    • 2002
  • Atomic coherences induced by the interaction with light provide new physical properties and optical phenomena. Even though two-photon resonances play important roles in build-up of atomic coherences, only approximate formula for two-photon resonance condition has often been used. In this paper, we present the more accurate two-photon resonance condition and confirm it using numerical simulation. We also studied the effects of laser frequency detuning and intensity on the two-photon resonance .

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Research trend in sugar alternatives (설탕 대체재 연구 동향)

  • Park, Ho-Young;Choi, Hee-Don;Kim, Yoonsook
    • Food Science and Industry
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    • v.49 no.3
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    • pp.40-54
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    • 2016
  • The recent much attention has been given to weight gain of the population and its consequences on the occurrence of diet-related diseases in developed countries. Sugar is considered to be the main culprit of these phenomena. Food manufacturers attempt to provide the consumer with reduced energy products with non-nutritional sugars. Some studies also showed that consumers preferred foods prepared with natural additives rather than chemical ones, due to health reasons. This article reviews issues related to sugar alternatives, as well as their use, health benefits and risks.

A Numerical Study on Two-Dimensional Turbulent Flow Field Around a Building (건물주위의 이차원 난류류동장에 대한 수치적 해석)

  • Won Sung Pil;Lee Dong Hwan
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.16 no.2
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    • pp.166-175
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    • 1987
  • The heat loss of a building within a wind flow field results from convection and natural ventilation. Loss from natural ventilation is much more than one from convection, and the former depends mostly on the pressure distribution at the building surface. Therefore, the objective of the present study is to calculate the pressure distribution and investigate flow phenomena, around the building with a rectangular shape in a two-dimensional turbulent flow field. The finite difference method, modelled upon the turbulence $k-\epsilon$ model, has been applied to the analysis. The results, followed by the changes of Reynolds numbers, inlet flow conditions, and building shapes, have been also obtained, respectively. Various results of the present numerical analysis coincide qualitatively well with earlier reported empirical results.

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Evaluating comparisons of geological hazards in landslides using fuzzy logic methods and hierarchical analysis

  • Shasha Yang;Maryam Shokravi;H. Tabatabay
    • Steel and Composite Structures
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    • v.48 no.5
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    • pp.499-505
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    • 2023
  • Geological hazards in landslide is one of the most extensive and destructive phenomena are among natural disasters. According to the topography high mountains, tectonic activity, high seismicity, diverse conditions Geology and climate, basically China to create a wide spectrum of landslides have natural conditions and these landslides are annual. They cause a lot of financial losses to the country. It is very difficult to predict the time of the landslide, hence the identification landslide sensitive areas and zoning of these areas based on the potential risk is very important. Therefore, it should be susceptible areas landslides should be identified in order to reduce damages caused by landslides find. the main purpose of landslide sensitivity analysis is identification high-risk areas and as a result, reducing damages caused by landslides It is the way of appropriate actions.

Sex Ratios of Juveniles Hatched by Constant Temperatures Artificial Incubation From Eggs Collected in the Natural Nest of Soft-Shelled Turtle, Trionyx sinensis Strauch (1862) (한국산 자라, Trionyx sinensis (1862)의 자연산란둥지에서 수거한 난들의 항온인공부화에 의해 출생한 새끼자라들의 성비)

  • KIM, Sung Han
    • Journal of Fisheries and Marine Sciences Education
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    • v.29 no.3
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    • pp.702-710
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    • 2017
  • Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

Measurements and CFD Analysis for Release Rate of CO2 and Characteristics of Natural Ventilation in Lecture Room (강의실 CO2 발생률과 자연환기 특성의 측정 및 CFD 분석)

  • Lee, Donghae;Choi, Youngbo
    • Journal of the Korean Society of Safety
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    • v.36 no.1
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    • pp.86-94
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    • 2021
  • Lecture rooms are crowded with many attendees. Moreover, they rely significantly on the natural ventilation through windows for removing and controlling indoor contaminants such as CO2. With the aim of broadening the understanding of the characteristics of natural ventilation phenomena in lecture rooms, the average individual CO2 release rates of attendees were measured during the course of a lecture and compared with previously reported CO2 release rates. In addition, the effects of natural ventilation through windows on the time-variant CO2 concentrations in the center of the lecture room were measured and analyzed. Moreover, details about the overall and regional CO2 concentrations, as well as the air flows in the lecture room, were simulated and analyzed with computational fluid dynamics software, Fluent 2020 R2. It was found that the average individual CO2 release rates were slightly slower than previously reported rates. The local CO2 concentrations in the lecture room for regions with a high density of attendees increased over a short period of time, although the natural ventilation was already started by opening the windows. The overall CO2 concentration in the lecture room rapidly decreased in the early stage of ventilation, but declined very slowly after a longer period of ventilation time. Therefore, in order to enhance the efficiency of a lecture room's natural ventilation, it is recommended to homogeneously distribute the attendees in the lecture room, and to frequently open the windows for short periods of time.