• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.4
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• pp.209-220
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• 2019

Even though the scale of hard structures for beach stabilization should carefully be determined such that these structures do not interrupt the great yearly circulation process of beach sediment in which the self-healing ability of natural beach takes places, massive hard structures such as the submerged breakwater of wide-width are frequently deployed as the beach stabilization measures. On this rationale, asymmetric ripple mat by Irie et al. (1994) can be the alternatives for beach stabilization due to its small scale to replace the preferred submerged breaker of wide-width. The effectiveness of asymmetric ripple mat is determined by how effectively the vortices enforced at the contraction part of flow area over the mat traps the sediment moving toward the offshore by the run-down. In order to verify this hypothesis, we carry out the numerical simulations based on the Navier-Stokes equation and the physically-based morphology model. Numerical results show that the asymmetric ripple mat effectively capture the sediment by forced vortex enforced at the apex of asymmetric ripple mat, and bring these trapped sediments back to the beach, which has been regarded to be the driving mechanism of beach stabilization effect of asymmetric ripple mat.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.617-622
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• 2013

The sloshing of liquid inside an ocean floater is caused by disturbances due to waves. For the analysis of sloshing impact within the floater and that of waves on the floater, the coupled analysis method is used. The Stokes $5^{th}$ order non-linear wave theory equations were adapted for wave making. Furthermore, Navier-Stokes equation and Shear-Stress Transport (SST) turbulent model were used to Computational Fluid dynamics, where the ocean floater motions are considered the heave and the pitch motion. The results obtained confirms the mutual relationship between the rigid body motions and that of sloshing, where the sloshing behaviour within the floater is characterized by the wave effects on the floater.

• Journal of Korean Traditional Oncology
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• v.15 no.1
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• pp.71-77
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• 2010

This case report documents a case in which the administration of an herbal product, an extract of the lacquer tree, Rhus verniciflua Stokes was related with a prolonged survival in a elderly advanced non-small cell lung cancer(NSCLC) patient. A 79-year-old man who had been diagnosed with advanced NSCLC refused conventional therapy and treatment with the allergen-removed Rhus verniciflua Stokes(aRVS) had continued from September 2007 to July 2010. He had survived for 35 months after the administration of aRVS and maintained good performance status with European Cooperative Oncology Group performance status(ECOG PS) of 1. This case suggests that aRVS be alternative treatment for the elderly advanced NSCLC patients.

• The Journal of Internal Korean Medicine
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• v.28 no.3
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• pp.655-661
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• 2007

Malignant melanoma is rare in Asians and one of the poorer prognostic diseases. Malignant melanoma accounts for only a small ratio of all skin cancers, but it causes the greatest number of skin cancer - related deaths worldwide. Melanoma incidence has continued to increase worldwide and in Korea, like other countries, the number of patients has increased compared with previous cancer incidence data. In this case report, we describe a case of a malignant melanoma patient who showed neck node metastasis (right supraclavicular area) after wide excision of facial melanoma 2 years before the diagnosis of relapse. The patient refused to get conventional western medical treatment including chemotherapy and the size of cancer increased over the 5 months of clinical follow-up. After 4 months of traditional Korean medical treatment using allergen-removed Rhus verniciflua Stokes(A-RVS), however, the size of cancer mass decreased and the patient showed no side effects. Further study will be needed in order to determine the long-term effect of allergen-removed Rhus verniciflua Stokes on patients with malignant melanoma.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.181-186
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• 2006

In this paper, generation mechanisms of ocean freak waves are briefly introduced in the context of wave-current interaction phenomena. The present model of the fluid motion is based on the Navier-Stokes equations incorporating velocity-pressure formulation because of need to model the nonlinear wave interaction with spatially non-uniform current field. In order to deal with the free surface motion, an Arbitrary Lagrangian-Eulerian (ALE) description is adopted. As an accurate and efficient numerical tool, the spectral element method is presented with general features and specific treatment for the wave-current interaction problem. As an intermediate stage of development, solution procedure and characteristics aspects of the present modeling and numerical method are addressed in detail, and preliminary numerical results prove its accuracy and convergence.

• Particle and aerosol research
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• v.17 no.4
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• pp.81-89
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• 2021

Understanding particle-laden flow around cylindrical bodies is essential for the better design of various applications such as filters. In this study, laminar flows around two tandem cylinders and the motions of particles in the flow are numerically investigated at low Reynolds numbers. We aim to reveal the effects of the spacing between cylinders, Reynolds number and particle Stokes number on the characteristics of particle trajectories. When the cylinders are placed close, the unsteady flow inside the inter-cylinder gap at Re = 100 shows a considerable modification. However, the steady recirculation flow in the wake at Re = 10 and 40 shows an insignificant change. The change in the flow structure leads to the variation of particle dispersion pattern, particularly of small Stokes number particles. However, the dispersion of particles with a large Stokes number is hardly affected by the flow structure. As a result, few particles are observed in the cylinder gap regardless of the cylinder spacing and the Reynolds number. The deposition efficiency of the upstream cylinder shows no difference from that of a single cylinder, increasing as the Stokes number increases. However, the deposition on the downstream cylinder is found only at Re = 100 with large spacing. At this time, the deposition efficiency is generally small compared to that of an upstream cylinder, and the deposition location is also changed with no deposited particles near the stagnation point.

• Fire Science and Engineering
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• v.30 no.4
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• pp.27-38
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• 2016

The paper reports the development of a distributed temperature sensing (DTS) system, which is a fire detection system using optical sensor linear detectors that depends on foreign and domestic technologies. This study accordingly analyzed the electrical signal patterns of Raman scattering light mainly used for temperature sensing among back-scattered light generated in optical fiber by using an oscilloscope. Through the measurement results, it could be verified that the Stokes signal patterns had little change by the temperature increase, but the temperature-sensitive anti-Stokes patterns had relative increase of the changes. This study developed a K-DTS system, which is an optical sensor linear fire detection system composed of an optical repeater and a receiver that can detect fires using Raman scattering light. It could be verified that the developed K-DTS system satisfied the type approval standards through the sensitivity tests using the rate of rise type and fixed temperature type sensitivity testers. In addition, performance experiments have been performed for performance evaluation of the K-DTS system developed in comparison with S-DTS system which has been imported from abroad and widely used in Korea. It can be confirmed from the results of the performance experiments using model tunnels that comparable performances can be obtained in fire detection locations and the measurements of fire temperatures.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.44-52
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• 2002

Aerodynamic characteristics of a flapping airfoil in low Reynolds number flows are numerically studied using the unsteady, incompressible Navier-Stokes flow solver with a two-equation turbulence model. For more efficient computation of unsteady flows over flapping airfoil, the flow solver is parallel-implemented by MPI programming method Unsteady computations are performed for low Reynolds number flows over a NACA four-digit series airfoils. Effects of pitching, plunging, and flapping motion with different reduced frequency, amplitude, thickness and camber on aerodynamic characteristics are investigated. Present computational results yield a better agreement in thrust at various reduced frequency with experimental data.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2175-2178
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• 2008

본 연구에서는 전면에 투과성 구조물이 위치한 직립케이슨 및 유공케이슨에 대해 수치모의를 실시하여 케이슨의 형태 및 투과성 구조물의 존재유무에 따른 반사율의 감소효과에 대하여 알아보았다. 수치모의에 사용된 모델은 비압축성 점성유체에 대한 복잡한 자유수면 변위의 표현이 가능한 VOF법을 적용하여 Navier-Stokes 방정식을 보다 정확하게 해석하는 CADMAS-SURF(수치파동수로)를 사용하였다. 상기 구조물에 규칙파를 입사하여 반사율을 산정한 결과 주기에 따라 차이가 있지만, 직립케이슨만이 존재하는 경우에 비해 직립케이슨 전면에 투과성 구조물이 위치한 경우 대략 5%정도의 반사율 감소효과를 얻을 수 있었고 유공케이슨만이 존재하는 경우에 비해 유공케이슨과 투과성 구조물이 조합 된 경우에는 20%이상의 감소효과를 얻을 수 있었다. 따라서, 방파제 전면에 위치한 구조물에 대한 반사파의 피해 감소 및 항만 내부 정온도를 고려한 안벽의 시공이 요구되어 질 경우에 투과성 구조물은 직립케이슨과의 조합보다는 반사율을 상대적으로 크게 감소시킬 수 있는 유공케이슨과의 조합이 적절함을 알 수 있었다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.77-84
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• 2005

A voloxidizer for a hot cell demonstration, that handles spent fuels of a high radiation level in a limited space should be small and spent fuel powders should not be dispersed out of the equipment involved. In this study a density rate equation as well as the Stokes'equation has been proposed in order to obtain the theoretical terminal velocity of powders. The terminal velocity of U$_{3}$O$_{8}$ has been predicted by using the terminal velocity of SiO$_{2}$, and then determination has been the optimum air flow rate which is able to prevent powders from scattering. An equation which has shown a relationship between theoretical terminal velocities of U$_{3}$O$_{8}$ and SiO$_{2}$ has been derived with the help of the Stokes'equation, and then an experimental verification made for the theoretical Stokes' equation of SiO$_{2}$ by means of an experimental device made of acryl. The theoretical terminal velocity based on the proposed density rate equation has been verified by detecting U$_{3}$O$_{8}$ powders in a filter installed in the mock-up voloxidizer. As the results, the optimum air flow rates seem to be 20 LPM by the Stokes'equation while they are 14.5 L/min by the density rate equation. At the experiments with the mock-up voloxidizer, a trace amount of U$_{3}$O$_{8}$ seems to be detectable at the air flow rate of 14.5 L/min by the density rate equation, but U$_{3}$O$_{8}$ powders of 7$\mu$m diameter seem detectable at the air flow rate of 20 L/min by the Stokes'equation. It is revealed that 14.5 L/min is the optimum air flowe rate which is capable of preventing U$_{3}$O$_{8}$ powders from scattering in the UO$_{2}$ voloxidizer and the proposed density rate equation is proper to calculate the terminal velocity of U$_{3}$O$_{8}$ powders.