• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.93-94
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• 2013

카이트 보딩은 윈드서핑, 요트 등과 같이 바람을 이용한 수상레저기구이며 국내에서는 소수의 동호인을 중심으로 매니아 층을 형성하고 있다. 최근 해양레저장비 분야에서도 친환경기술과의 접목이 진행되고 있으며, 특히 해외에서는 대형선박의 연료비 절감 및 환경오염 인자 저감을 위한 선박 추진용 카이트 시스템이 개발되어 사용 중에 있다. 본 연구에서는 카이트 추진형 레저보트를 대상으로 풍속, 풍향, 카이트의 위치 등에 따라 자동제어 및 운항 가능한 시스템을 제안하고자 한다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.35-36
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• 2001

전보의 무부자망은 해상시험 조업의 결과, 망구의 전개 및 중ㆍ저층에서의 예망수층 조절등이 손쉽게 이루어지는 것이 확인되었으나 뜸줄부가 표층 ∼ 30m에서의 예망수심조절이 어렵다는 것이 확인되었다. 따라서, 무부자망은 망구전개가 F.W(Front weight)의 침강력에 의하여 이루어지므로 어구의 예망수심의 깊이 조절이 한계를 받으므로 이것을 극복하기 위하여 카이트(Kite)를 도입하기로 하고 본 연구를 실시하였다. (중략)

• Journal of the Mineralogical Society of Korea
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• v.14 no.2
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• pp.119-127
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• 2001

FTIR spectroscopic study was undertaken on dickite and pyrophyllite with Si and Al cations in the far-infrared(Far-IR) and mid-infrared (Mid-IR) regions, respectively. Attempts were made to present bonding information and make assignments on the absorption bands of dickite in the Far-IR region. Dickites contain a small proportions or kaolinite or nacrite layers. FTIR can be used as a potential tool for characterizing the presence of mixed-layer with different polytypes of the kaolin minerals. There is no clear relationship between Hinckley index and crystallinity of dickite. Although pyrophyllite shows a strong OH stretching band at 3673-3676 $cm^{-1}$ / corresponding to an inner hydroxyl group, the weak band at $3645-3648 cm^{-1}$ seems to be due to the symmetric vibration if the symmetry of the structure is not ideal, probably due to the presence of trace Fe or mixture phases of 1Tc and 2M polytypes.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.1
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• pp.33-40
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• 2023

Todorokite is a manganese oxide mineral containing Mg²⁺ in a tunnel structure in which MnO₆ octahedra share corners. In order to investigate the suitability and efficiency of high temperature-treated todorokite as a material for adsorption and fixation of Cs, Cs was ion exchanged and the amount of leached Cs from todorokite was measured. The todorokite used in this study was synthesized by transforming Na-birnessite to Mg-buserite and used as a precursor. After high temperature treatment, Cs exchanged todorokite changed to birnessite and hausmannite as the temperature increased. The amount of leached Cs was investigated for Cs exchanged todorokite which was reacted with distilled water and 1 M NaCl solution at different reaction times. In general, for the samples reacted with 1 M NaCl solution, the fixation of Cs was quite effective, although the amount of leached Cs was greater due to the ion exchange reaction with Na. As the treatment temperature increased, the amount of leached Cs increased and then decreased again, which was related to the mineral phases formed at each temperature. As birnessite was formed, the amount of leached Cs increased, but as birnessite decreased, that decreased again. As the mineral phase changed to hausemanite, the amount of Cs decreased rapidly. The results of our study show that Cs exchanged todorokite can be used as a material that effectively fixes Cs and prevents its diffusion by high temperature treatment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.3
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• pp.197-210
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• 2003

The non-float midwater pair trawl was effective in the mouth opening and control of the working depth in midwater and bottom. In contrast, we confirmed that it was difficult to keep the net at surface above 30 m of the depth by means of the full scale experiment in the field and the model test in the circulation water channel. To solve this problem, the kites were attached to the head rope of the non-float midwater pair trawl. In this study, four kinds of the model experiments were carried out with the purpose of applying the kite to the korean midwater pair trawl. The results obtained can be summarized as follows: 1. The working depth of the non-float midwater pair trawl with the kite was shallower than that of the proto type and non-float type. The working depth of the kite type was approximately 20m with 2 kites and about 5m with 4 kites under 4.0 knot. The working depth was almost constant but the depth of the head rope sank approximately 15m and 10m according to the increase in the front weight and the wing-end weight, respectively. The changing aspect of the working depth was constant, but the depth of the head rope sank approximately 22m according to the increase in the lower warp length (dL). 2. The hydrodynamic resistance of the kite type was almost increased in a linear form in accordance with the flow speed increase from 2.0 to 5.0 knot. The increasing grate of the hydrodynamic resistance tended to increase in accordance with the increase in flow speed. The hydrodynamic resistance of the kite type was larger approximately 5～10 ton larger than that of the non-float type and the proto type. The hydrodynamic resistance of the kite type increased approximately 3ton with the changing of the front weight from 1.40 to 3.50 ton and approximately 4 ton with the changing of the wing-end weight from 0 to 1.11 ton and approximately 5.5 ton with the changing lower warp length (dL) from 0 to 40 m, respectively. 3. The net height of the kite type was increased approximately 10 m with the change in the kite area from $2,270mm^2$ to 4,540 $\textrm{mm}^2$. The net height of the kite type was aproximately 50 m and 30 m larger than that of the proto type and the non-float type, respectively. The changed aspect of the net width was approximately 5m with the variation of the flow speed from 2.0 to 5.0 knot. 4. The filtering volume of the kite type was larger than that of the proto type and the non-float type by 28%, 34% at 2.0 knot of the flow speed and 42%, 41% at 3.0 knot, and 62%, 45% at 4.0 knot, and 74%, 54% at 5.0knot, respectively. The optimal towing speed was approximately 3.0 knot for the proto type and was over 4.0 knot for the non-float type, and the optimal towing speed reached 5.0 knot for the kite type. 5. The opening efficiency of the kite type was approximately 50% and 25% larger than that of the proto type and the non-float type, respectively.

• Journal of the Mineralogical Society of Korea
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• v.13 no.4
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• pp.205-220
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• 2000

북동태평양 C-C지역의 우리나라 광구에서 산출되는 망간단괴의 내부조직을 크게 주상조직 층상대, 첨상조직 층상대, 첨상조직 괴상대, 첨상조직 다공질대 및 괴상조직 괴상대로 구분하였다. 주상조직 층상대에서는 버나다이트(vernadite)가 가장 우세하게 산출되며, 첨상조직 층상대에서는 부서라이크(buserite)가 함께 산출된다. 첨상조직 괴상대는 부서라이트의 산출이 두드러지며, 부분적으로 토도로카이트(todorokite)가 수반된다. 첨상조직 다공질대는 첨상체 또는 구상체로 이루어지며 부분적으로 괴상조직으로 교대되는데 주로 토도로카이트와 부서라이트로 구성되어 있다. 괴상조직을 갖는 괴상대에서는 토도로카이트와 버네사이트(birnessite)가 부서라이트와 함께 산출된다. 각 조직대별로 미세조직을 이루는 엽리들에 대해 전자현미분석을 실시하였다. 엽리의 화학조성을 구성하는 요인은 상관계수 군집분석에 의해 Mn-K의 Mn군, Cu-Ni-Zn-Mg(Ca-Na)의 Cu-Ni-Mg군 Fe-Co-Ti(Ca-P)의 Fe군과 Si-Al의 Si군 등 네 개군으로 구분된다. 각 조직대는 세 개 또는 네 개의 군으로 구성되며 이들 각군은 단괴에서 산출되는 광물과 밀접한 관계를 가진다. Mn군은 토도로카이트, Cu-Ni-Mg군은 부서라이트, Fe군은 함코발트수산화철광물, 그리고 Si군은 규산염광물에서 주로 기인하는 것으로 생각된다. 엽리의 화학조성은 이들 광물의 조합과 구성광물의 화학조성에 따라 지배되고 한 조직대내에서도 여러종류의 조합을 보이는데 이는 각 조직대의 엽리들의 성인과 밀접한 관련이 있는 것으로 생각된다.

• Journal of the Mineralogical Society of Korea
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• v.32 no.3
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• pp.151-162
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• 2019

Todorokite, a tunnel-structured manganese oxide, can contain cations within the relatively large nanopores created by the $3{\times}3$ Mn octahedra. Because todorokite is poorly crystalline and found as aggregates mixed with other phases of Mn oxides in nature, the coordination structure of cations in the nanopores is challenging to fully characterize in experiment. In the current article, we report the atomistic coordination structures of $Mg^{2+}$ ions in todorokite tunnel nanopores using the classical molecular dynamics (MD) simulations. In experiment, $Mg^{2+}$ is known to occupy the center of the nanopores. In our MD simulations, 60 % of $Mg^{2+}$ ions were located at the center of the nanopores; 40 % of the ions were found at the corners. All $Mg^{2+}$ located at the center formed the six-fold coordination with water molecules, just as the ion in bulk aqueous solution. $Mg^{2+}$ ions at the corners also formed the six-fold coordination with not only water molecules but also Mn octahedral surface oxygens. The mean squared displacements were calculated to examine the dynamic features of $Mg^{2+}$ ions in the one-dimensional (1D) nanopores. Our MD simulations indicate that the dynamic features of water molecules and the cations observed in bulk aqueous solution are lost in the 1D nanopores of todorokite.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.3
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• pp.59-68
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• 2012

Zero client-based cloud storage technology is gaining much interest as a tool to centralized management of organizational documents nowadays. Besides the well-known cloud storage's defects such as security and privacy protection, users of the zero client-based cloud storage point out the difficulty in browsing and selecting the storage category because of its diversity and complexity. To resolve this problem, this study proposes a method of intelligent document archiving by applying an algorithm-based automatic topic identification technology. Without user's direct definition of category to store the working document, the proposed methodology and prototype enable the working documents to be automatically archived into the predefined categories according to the extracted topic. Based on the proposed ideas, more effective and efficient centralized management of electronic documents can be achieved.

• Proceedings of the Petrological Society of Korea Conference
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• 1999.06a
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• pp.90-93
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• 1999

• Proceedings of the Petrological Society of Korea Conference
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• 2003.05a
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• pp.1-3
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• 2003