• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.805-812
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• 2006

In this study the description patterns of chemistry textbooks on the boiling point elevation phenomenon and the understanding patterns of high school students, pre-service teachers and chemistry teachers were investigated. High school chemistry II textbooks developed in the 6th and 7th national curricula were analyzed and the conception patterns of subjects on this phenomenon were categorized using a questionnaire developed for this study. The description patterns of science textbooks were classified into three: 'decreasing of surface solvent molecules', 'attraction force between solvent and solute molecules' and 'decreasing of surface solvent molecules and attraction force between solvent and solute molecules'. In the result of the conception analysis, the ratio of 'attraction force between solvent and solute molecules' was high among students, pre-service teachers, and chemistry teachers. There was a propensity that they would like to explain the boiling point elevation in terms of enthalpy rather than entropy, and in order to analyze this propensity, follow-up interviews were carried out.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.38-49
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• 2015

Past study of tsunami heavily relied on the numerical modelling using 2D Boussinesq Eq. and Solitary wave. Lately, based on the fact that numerically simulated run up heights based on solitary wave are somewhat smaller than the measured one, Leading Depression N (LDN) Wave has been elaborated, which can account the advancement of a shore line before tsunami strikes a shore. Thereafter it is reported that more accurate simulation can be possible once LDN is deployed. On the other hand, there were numerous reports indicating that stable LDN wave can't be sustained in the hydraulic model test. These conflicts between the hydraulic model tests and numerical results have their roots on the assumption made in the derivation of Boussinesq type wave model such as that wave nonlinearity is equally balanced with wave dispersiveness. Hence, in the numerical simulation based on the Boussinesq type wave model, wave dispersiveness is inevitably underestimated, especially in deep water. Based on this rationale, we developed the modified methodology for the generation of stable LDN wave in the 3D numerical wave flume, and proceeded to numerically analyze the depression effect of Hybrid Breaker on the run up height due to tsunami using the Navier Stoke Equation. The verification of newly proposed wave model in this study was carried out using the run up height from the hydraulic model test. It was shown that Hybrid Breaker consisting of three water chamber and slope at its front can reduce 13% of run up height for H = 5m, and 10% of run up height for H = 6m.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.711-719
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• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.

• Water for future
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• v.38 no.4 s.147
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• pp.115-119
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• 2005

• 한국호스피스협회지
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• s.124
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• pp.8-11
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• 2011

• Water for future
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• v.29 no.2
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• pp.71-76
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• 1996

• Korean Architects
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• s.661
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• pp.102-109
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• 2024

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.44-51
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• 1996

The accurate calculation of run-up heights of long waves along the coastline is important in the view of engineering. In this paper the run-up heights of long waves are estimated by using the cnoidal wave theory which also covers both sinusoidal and solitary waves. However, the generation and the calculation of run-up heights of cnoidal waves are difficult both in laboratory and numerical experiments. In this study, the maximum run-up heights of cnoidal waves on steep slopes are computed by using the boundary integral equation model. It has been shown that the run-up heights of cnoidal waves are less than those of solitary waves, while they are larger than those of sinusoidal waves having the same wavelengths and heights. The variation of run-up heights of cnoidal waves is not a monotonic function of the wavelength. However, the run-up heights of cnoidal waves asymptotically approach that of a solitary wave as the wavelength approaches infinity. The calculated run-up heights agreed reasonably with experimental data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4B
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• pp.429-439
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• 2008

The purpose of this study is to examine the characteristics of run-up height over sandy beach due to the shape of submerged breakwater. For the discussion on it in detail, 3-Dimensional numerical model with Large Eddy Simulation, which is able to simulate directly interaction of Wave Structure Sandy beach (hereafter, LES-WASS-3D; Hur and Lee, 2007) has been used to simulate run-up height over sandy beach as well as wave field around submerged breakwaters. Using the results obtained from numerical simulation, the effects of the shape of submerged breakwaters (crown height, crown width, crown length and submerged breakwater's slope gradient) on run-up height over sandy beach have been discussed related to the wave height distribution and characteristics of up-layer flow around ones.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.101-109
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• 2012

Traditional village forests in Jeju Island represent unique cultural landscape with a history of more than several hundred years as a national cultural asset in Korea. In this paper, the characteristics and meaning of traditional village forests in Jeju Island was compared with the Dangsan and Bibo forests at inland. There are 368 Oreums, parasitic volcano, and 391 shrines of Dang(Divine place) in Jeju. Life, culture and tradition of rural villages are all connected with the Dang and Oreum in Jeju. It has been found from this study that the village in Jeju were established as a cultural landscape on the surface of natural landscape. The features of traditional villages focused on the Dang and Oreum in Jeju Island were similar to the Dangsan and Bibo forestsat inland villages. The Oreum represents mountain and the Pojedan forest is newly found in Sangmyung-ri. The seashore areas are covered by vaocanic rocks in Jeju and large scale windbreaks are hardly found. The stone tower at Sinheung-ri built for blocking sand movement represents Bibo forest. The special attribute of the Dang in Jeju is that it is close to real life and believers are still remain. In 2009, the Jeju Chilmeoridang Yeongdeunggut ritual was nominated as an Intangible Cultural Heritage of Humanity by UNESCO. The shrine of Dang, however, has been degraded fast by construction of seashore road and Jeju Olle trail path. As for the world cultural heritage discussed at international conferences, it is important that there is sustainability on the right to enjoy cultural heritage. Integrated efforts from local residents, local governments and national government are needed to set up a management scheme for the Dang culture. Rural villages in Jeju with the Dang and Oreum are expected to get an international attention as to have traditional cultural landscapes of Korea.