• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.509-513
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• 2020

The performance of TiO₂ microcones/CNT composites as an anode material for lithium ion batteries was investigated. TiO₂ microcones/CNT composites were prepared by the polarization followed by electrophoretic deposition approaches on anodic TiO₂ microcones, which were composed of individual nanofragments resulting in a large surface area where lithium ion can be stored. Compared to pristine TiO₂ microcones, TiO₂ microcones/CNT composite electrodes showed higher areal capacity with a stable cyclability due to an enhanced electrical and lithium ion conductivity. Furthermore, TiO₂ microcones/CNT composite electrodes exhibited good cycle life characteristics and excellent rate retention under a high current density of up to 20 C.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.466-473
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• 2011

The purpose of this study is to analyze the distribution of the building area and find the characteristics of development density where the areas to perform special functions as residential, commercial, and business area in Seoul. As a result of classification of the regions with the component ratio of building area ratio by types, the greater part of Seoul is residential areas and only a small part of Seoul have business function. Contrary to the Kang-Nam business districts, the central business districts have few or no houses. It is concerned that the redevelopment projects, such as New-Town, make Seoul more high- density. The industrial area lost the attractiveness as a resident in spite of businesses or infrastructures. So the industrial area will be the best place for reduce journey-to-work distance if improve housing conditions. As well as management of density, management of use is also required for effective landuse and green-growth city.

• Convergence Security Journal
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• v.15 no.6_1
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• pp.25-31
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• 2015

It depend on relative combat power, patriotism and cohesion of citizen to victory in the battlefield. This stu dy try to analysis why the Germany army fail 'the Battle of the Bulge'. The Germany army plan of maneuve r to attack the France army was surprise attack in the beginning of World War II. The Germany army have initiative to make breakthrough Ardennes Ridge. The operation of the Ardennes Offensive Operation and the Battle of the Bulge is the typical features of blitzkrieg shock. However, the results are extremely different. In the course of the operational planning and decision the course of action, military security is most important fa ctor. We can see the truth in 'the Battle of the Bulge'.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.72-75
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• 2003

In this research, we focused on the effects of the orifice internal flow such as cavitation and hydraulic flip. The breakup characteristics such as the breakup length and trajectory were measured by changing the orifice diameter (d), the orifice length/orifice diameter (L/d), the injection pressure and the shapes (sharp and round) of orifice entrance to provide a lot of conditions of the orifice internal flow. It is found that cavitation bubbles that occur inside the sharp-edged orifice make the liquid jet ejecting from the orifice turbulent. In the orifices (L/d = 5), the hydraulic flip phenomenon is shown when the injection pressure is high. In case cavitation occurs it breaks up more earlier than that in case of non-cavitation. In case hydraulic flip occurs, since the area of the liquid jet becomes small, the breakup length is also small as that in case of cavitation. But the liquid column trajectories have a similar tendency irrespective of cavitation.

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.67-67
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• 2010

과학교육에서 효과적인 과학 수업을 위하여 과학사 도입의 중요성이 계속 강조되어 왔다. 이에 따라 과학 교과서에는 많은 과학사 자료가 사용되고 있다. 하지만 과학 교과서에 사용된 과학사 자료가 어떤 유형과 맥락에서 어떠한 역할을 하고 있는 지에 대한 면밀한 분석은 이루어지지 못한 실정이다. 이에 본 연구에서는 선행 연구와 관련 문헌 분석을 통해 과학 교과서에 사용된 과학사 자료를 분석하기 위한 3차원 틀을 개발하고, 이를 제 7차 교육과정의 과학 교과서 지구과학 내용을 대상으로 적용하였다. 개발된 분석틀은 수업맥락, 역할, 제시유형의 3개 차원으로 구성된다. 수업맥락 차원은 흥미, 사회-문화적, 인식론적, 개념적 맥락의 4가지 영역으로 세분되며, 제시유형 차원은 에피소드/일화, 발견/고안, 선형적인 발전, 역사적 실험의 4가지 영역으로 세분된다. 역할 차원은 기본적, 보충적, 탐구적의 3가지 영역으로 세분된다. 개발된 3차원 분석틀을 적용하여 과학 교과서의 지구과학사 자료들을 분석한 결과, 수업맥락 차원에서는 개념적 맥락의 과학사 자료가 모든 학년별 과학 교과서에서 가장 많았다. 역할 차원에서는 기본적 역할이 압도적으로 많았으며, 탐구적 역할의 경우에는 매우 적었다. 제시유형 차원에서는 발견/고안과 선형적인 발전 유형이 대부분이었고, 에피소드/일화 유형의 자료는 주로 흥미 맥락과 연계되어 극히 일부만 사용되고 있었다. 3차원 각 영역들을 48개의 조합으로 분석한 결과, '개념적 수업맥락-기본적 역할-발견/고안 유형'과 '개념적 수업맥락-기본적 역할-선형적 발전 유형' 2개 조합에 집중되었으며, 나머지 조합들의 빈도는 매우 낮았다. 전체적으로 3차원 분석틀 각 영역에 부합하는 과학사 자료가 과학 교과서에 다양하게 포함되지 못하고 일부 영역에만 집중되는 것으로 나타났으며, 이러한 연구 결과는 앞으로 다양한 수업맥락, 역할, 그리고 유형으로 과학사 자료들이 개발될 필요가 있음을 시사한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.404-413
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• 2015

The target classification for ballistic target(BT) is one of the most critical issues of ballistic defence mode(BDM) in multi-function radar(MFR). Radar responds to the target according to the result of classifying BT and air breathing target(ABT) on BDM. Since the efficiency and accuracy of the classification is closely related to the capacity of the response to the ballistic missile offense, effective and accurate classification scheme is necessary. Generally, JEM(Jet Engine Modulation), HRR(High Range Resolution) and ISAR(Inverse Synthetic Array Radar) image are used for a target classification, which require specific radar waveform, data base and algorithms. In this paper, the classification method that is applicable to a MFR system in a real environment without specific waveform is proposed. The proposed classifier adopts kinematic data as a feature vector to save radar resources at the radar time and hardware point of view and is implemented by fuzzy logic of which simple implementation makes it possible to apply to the real environment. The performance of the proposed method is verified through measured data of the aircraft and simulated data of the ballistic missile.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.397-403
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• 2015

In this paper, a method of ISAR geometric calibration is represented by using impulse-radio UWB radar. The ir-UWB is good for using a signal processing in time domain, so, it does not occur a multi-path or coupling problem. If a signal that between antennas and target is assumed a plane wave, a center of rotation in ISAR geometry model can be estimated by using point target. Before image is reconstructed with sinogram, the center of rotation can be calculated by using least square fitting. This method can be obtained a more contrast image, and a maximum value of entropy of image. The method, that estimates a center of rotation in received data, will be used a initial setup of instruments or a periodic compensation to reconstruct image. It would be useful in medical, security and surveillance imaging equipments that have a fixed geometry.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.199-207
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• 2003

In the combat environments at the sea, the naval ships should have enough structural integrity to perform the task under the enemy's attack and possible damages. Although the naval ships can be damaged from the enemy's attack, those damages should be minimized and the naval ships must maintain their combat capabilities continuously after recoveries from the damages. Therefore, it is ve교 important for modem naval ships, especially combat naval ships, to ensure the survivability. This paper reviewed the developing procedure for the technique of the naval ships structures and described method, especially box girder system considering survivability. The efficiency of box girder is examined by numerical simulation, and it is found that the establishment of box girder is a good design method to improve the survivability.

• Convergence Security Journal
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• v.16 no.6_1
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• pp.51-58
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• 2016

"History is a mirror" means that we should be prepared for the threats of enemies through learning from repeating history. Currently South Korea is facing various provocations, including North Korea's nuclear weapons and missile s. For the protection of the life and property of its people, South Korea should regard North Korea as a main enemy and be fully prepared for the threats. The Korean War was a war between well-prepared North Korea and ill-prepa red South Korea. After Liberation, North Korean army incorporated the Chinese Communist army, placed battle equi pment with the support of the Soviet army, and finished corps-level training while South Korea at that time did not finish battalion-level training. In wartime and peacetime, an army should improve military security by concealing its own information and find its enemy's information. North Korea carefully prepared for the war, collecting information about the organization, deployment and operation of the South Korean army. South Korean army failed to cope with it and had hard times in its early battles. In this paper, I will emphasize the importance of military security, focusing on the Battle of Gaeseong, the early part of the Korean War.

• Composites Research
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• v.13 no.4
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• pp.33-41
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• 2000

In this research, the mathematical modeling of the formation of SiC layer on the activated carbon was studied to improve the durability and the oxidation resistance of catalyst supports. SiC layer on the activated carbon was formed by permeating SiC from dichlorodimethylsilane(DDS) into pores and depositing while the porous structure was kept. The best conditions of manufacturing the support were found by studying the characteristics of SiC/C which was modelled under various deposition conditions. Changes of the amount of deposition, the pore diameter, the surface area with time were obtained by simulating convection, diffusion and reaction in an isothermal reactor at a steady state. The uniform deposition in the pores of samples was obtained at a lower concentration of the reactant and a lower pressure. Additionally, it was observed that the pore diameter and the surface area have points of inflection at certain times of deposition, because deposition occurred on the inside surface of the pore at first and then on the outside surface of the particle.