• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.166-166
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• 2017

금속 재료 중 철강은 기계적 특성이 우수하고 대량생산이 가능하여 선박, 건축, 자동차 등 다양한 분야에 기초재료로써 널리 사용되고 있다. 그러나 스테인리스강 등과 같은 일부 특수한 용도의 강을 제외하고는 부식환경에 취약한 특성을 가지기 때문에 내식성을 향상을 위한 표면처리에 관한 연구가 활발히 진행되고 있다. 가장 일반적으로 습식법(wet process)을 통해 표면상에 아연(Zn)을 도금해 사용하며, 아연이 자체적으로 포함한 희생양극(sacrificial anode) 및 차폐(barrier) 효과가 철강의 부식을 방지하게 된다. 하지만 산업의 고도화에 따라 더욱 가혹해진 노출환경으로 인해 고내식 강재에 대한 수요가 점차 증가하고 있으며, 아연코팅 층의 두께를 증가하여 내식성을 확보하는 방안은 미래 환경 및 자원적인 측면에서 근본적인 해결책으로 제시하기 어려움이 있다. 한편, 건식 프로세스(wet process)로 대별되는 PVD(physical vacuum deposition)에 의해 내식성을 향상시키고자 하는 연구들이 다양하게 진행되고 있다. 이것은 표면에 고순도 양질의 금속 막을 형성시킴으로써 외부환경과의 반응을 효과적으로 제어가 가능하며, 형성된 막은 그 물질의 고유 특성뿐만 아니라 제작 조건에 따른 표면의 기하학적 혹은 결정학적 구조에 의해 크게 영향을 받게 된다. 본 연구에서는 실용금속 중 이온화 경향이 가장 크고 산소와 반응하여 투과성이 작은 산화 피막 형성이 유리한 마그네슘(Mg)을 활용해 표면의 전기화학적 특성을 향상시켰다. 또한 금속 증착 중 진공도조절을 위해 도입되는 불활성 가스로 아르곤(Ar) 및 질소($N_2$)를 사용하여 표면에 형성한 막의 모폴로지 및 결정배향성이 내식성에 미치는 상관관계를 해석하고자 하였다. 실험방법으로 PVD법 중 비교적 간편하고 기초적인 지침을 제시하기 적합할 것으로 고려된 진공증착(vacuum evaporation)법을 이용해 아르곤 및 질소 분위기에서 진공도를 조절하며 용융아연도금상 Mg막을 형성하였다. 제작조건별 막의 기초 특성을 분석하기위해 SEM, EDS, XRD를 이용하였고, 결정배향성(crystal orientation) 분석을 위해 면간격(d-value)과 상대강도(relative intensity)를 확인하였다. 또한 내식성 평가로 염수분무(salt sprat test) 및 양극분극(anode polarization)을 각각 실시하였다. 실험결과에 따르면, Ar 및 $N_2$ 모두에서 가스압이 증가할수록 코팅층의 증착량은 적어지고 입상정(granular structure)의 모폴로지 형성 및 면간격과 상대강도가 증가하는 것이 확인되었다. 또한 쳄버 내 동일 진공도에서, $N_2$ 도입 시 Mg막은 더욱 치밀하고 미세한 입상정의 모폴로지로 형성되며 면간격과 상대강도는 더욱 증가한 것으로 나타났다. 내식성 평가에서 저진공 $N_2$ 조건에서 형성시킨 막이 가장 우수한 내식성이 나타났는데, 이는 상대적으로 불안정하고 반응하기 유리한 입계면적을 많이 포함한 입상정 모폴로지 및 표면에너지가 높은면의 면점유율 증가로 인해 외부환경과의 신속한 반응은 물론 안정적인 피막형성이 용이하였기 때문일 것으로 사료된다. 이상으로 Ar 및 $N_2$ 가스압 조건에 따른 고내식 Mg 막의 유효성을 확인하였고 향후 내식성을 향상시키는 방법으로 응용 가능할 것으로 생각된다.

• Journal of Information Management
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• v.25 no.1
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• pp.24-46
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• 1994

In this paper I will discuss definitions of hypermedia, multimedia and hypertext. Hypertext is the grouping of relevant information in the form of nodes. These nodes are then connected together through links. In the case of hypertext the nodes contain text or graphics. Multimedia is the combining of different media types for example sound, animation, text, graphics and video for the presentation of information by making use of computers. Hypermedia can be viewed as an extension of hypertext and multimedia. It is based on the concept of hypertext that uses nodes and links in the structuring of information in the system. In this case the nodes consist of an the different data types that are mentioned in the multimedia definition above. The 'node-and-link' concept is used in organisation of the information in hypermedia systems. The 'book' metaphor is an example of the way these systems are implemented. This concept is explained and a few advantages and disadvantages of making use of hypermedia systems are discussed. A new approach for the development of hypermedia systems, namely the knowledge-based approach is now looked into. Joel Peing-Ling Loo proposed this approach because he thought that it is the most effective way for handling this kind of technology. A semantic-based hypermedia model is developed in this approach to formulate solutions for the restrictions in presenting information authoring, maintenance and retrieval. The knowledge-based presentation of information includes the use of conventional data structures. These data structures make use of frames(objects), slots and the inheritance theory that is also used in expert systems. Relations develop between the different objects as these objects are included in the database. Relations can also exist between frames by means of attributes that belong to the frames.

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.91-100
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• 1999

The purpose of this study is to make a plan for the development of new tour routes for '98 Kyongju World Culture Exposition. The result of this study is as follow: First, over 40% of tourists from Kyongsang-buk-do Province vote for Kyongju Area as the most favorite tourist-oriented city in this province. And they are visiting Kyongju mostly in April(22.6%) and in May(17.8%). Second, cultural assets in Kyongju area are located at Inkyo-dong(16.8%), at Bohwang-dong(9.4%), at Topjong-dong(8.1%). at Mt. Namsan area(11.8%, 6.9% for Naenammyon, and 4.9% for Dodong-dong), and at the vicinity of Kyongju City(53.9%). Third, tourism enterprises in Kyongju Area are located mostly at one place-Pomun Lake Resort area. This fact have had bad influence on the influx of tourists. Lastly, current tour routes are limited mostly to the heart of Kyongju City. So, other attractive tour routes must be developed also in other tourism circles such as the East Sea Tourism Circle and the Northern Province Tourism Circle, which belong to the 6 tourism circles designated by Kyongju City but are now excluded from the current tour routes. In conclusion, this study proposes "98 Kyongju World Culture Exposition with Themes" related to the 6 tourism circles. The themes proposed are as follows: (1) The exploration of the historical places of the Shill a Kingdom in the heart of Kyongju City including Mt. Seoak area and Pulkuksa Temple area. (2) Smile with a new millenium in Pomun Lake Resort area. (3) The exploration of the Buddhist culture in Mt. Namsan. (4) The harmony between nature and culture in the East Sea Tourism Circle and the Northern Culture Circle.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.21-29
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• 1985

An effective technique of sludge separation is required for concentrated activated sludge process. The dissolved-air flotation (DAF) has been shown to be efficient process for sludge separation. The factors affecting DAF process for activated sludge separation are type and concentration of sludge, air/solid ratio, ratio of pressurized water flow, pressure, sludge detention time, temperature, sludge and hydraulic loading rate, recycle flow rate of sludge and type and quantity of chemical aid. In order to study the optimal operation condition for sludge separation, the influence factors such as type and concentration of sludge, ratio of pressurized water flow and pressure are investigated by the batch and continuous reactor experiments of DAF and sedimentation test. By the experimental investigation, the results are as follows; 1. For the bulking and concentrated sludge, DAF is more effective than sedimentation for the sludge separation. 2. In DAF, the critical ratio of pressurized water flow exist. The critical value varies with the pressure in the tank. That is, according to the pressure changes from 3 to $5kg/cm^2$, the critical value varies from 0.25 to 0.67 accordingly. 3. Pressure affects the ratio of pressurized water flow, but it does not show any influence upon the DAF efficiency directly. 4. Continuous experimental results was not better than those of batch.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.155-161
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• 2009

Lithium secondary batteries have been widely used in the portable electric devices as power source. Recently it is expected that the realm of its applications expands to the markets such as energy storage medium of hybrid electric vehicle(HEV), electric vehicle(EV). Cathode active material is crucial in terms of performance, durability, capacity of lithium secondary batteries. It is urgent to develope the technology for mass production of cathode material to cope with the markets' demands in the near future. In this study, a calcination furnace running in real production line is modelled in 3D, and the thermal flow and gas flow after chemical reaction in the furnace is analyzed through numerical computations. Based on the results, it is shown that large volume of $CO_2$ gas is generated from chemical reaction. High concentration of $CO_2$ gas and it's stagnation is clearly found from the reactant containers in which the reaction occur to the bottom area of the furnace. It is also studied that 15% or more $CO_2$ mol fraction could affect to proper formation of $LiCoO_2$ through TGA-DSC analysis. The solutions to evacuate carbon dioxide from the furnace are suggested through the change of furnace design and operating condition as well.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.2
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• pp.93-106
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• 2011

This review has dealt with definition, size, history, and status of mesocosm, and also discussed several problems and trouble shootings related to the building of mesocosm, and finally will suggest the future directions of this scientific tool. Due to the restriction of the space, the discussion mainly focused on "the mesocosm building for the soft-bottom ecosystem". The mesocosm is defined as "medium-sized, self-sustaining, and man-controllable ecosystem". This type of studies has already initiated since 1960, but nowadays it expands to the diverse fields of science and technologies, such as toxicology, limnology, environmental sciences and engineering, and even geochemistry. As a scientific tool, the mesocosm requires following aspects; replicability, repeatability, and ecological realism or accuracy. Several technical problems have to be solved for the perfect building of mesocosm. They are known as scaling, composition of seawater/sediment, light intensity, turbulence, hydraulic residence time, and top predator. These trouble shootings are provided at the discussion in detail. In the context, I expect two promising directions in the future; 1. Objectivity based on the diverse statistical methodologies, 2. "Living ecosystem modelling" coordinated with the mathematical modelling. With these, the mesocosm will be more powerful tool for the scientists and engineers to investigate the chemical and the ecological responses to the toxic materials and global climate changes.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.197-205
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• 2010

Recently abrupt climate changes have been occurred in global and regional scales and $CO_2$ reduction technologies became an important solution for global warming. As a method of the solution shallow underground thermal energy storage (UTES) has been applied as a reliable technology in most countries developing renewable energy. The geothermal energy system using thermal source of soil, rock, and ground water in aquifer or cavern located in shallow ground is designed based on the concept of thermal energy recovery and storage. UTES technology of Korea is in early stage and consistent researches are demanded to develop environmental friendly, economical and efficient UTES systems. Aquifers in Korea are suitable for various type of ground water source heat pump system. However due to poor understanding and regulations on various UTES high efficient geothermal systems have not been developed. Therefore simple closed U-tube type geothermal heat pump systems account for more than 90% of the total geothermal system installation in Korea. To prevent becoming wide-spread of inefficient systems, UTES systems considering to the hydrogeothemal properties of the ground should be developed and installed. Also international collaboration is necessary, and continuous UTES researches can improve the efficiency of shallow geothermal systems.

• Research in Plant Disease
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• v.15 no.3
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• pp.198-201
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• 2009

Bacterial wilts, caused by Ralstonia solanacearum, is a very destructive disease to tomato plants (Solanum lycopersicum) in Korea. Selection of resistant cultivar is the best way to prevent or reduce the occurrence of this disease. Thirty-nine tomato cultivars, twenty-one cherry tomato cultivars and thirteen rootstock tomato cultivars were inoculated with Ralstonia solanacearum, to evaluate tomato cultivars for resistance against bacterial wilts. Thirty-seven cultivars were highly susceptible to bacterial wilts and 61-100% of their whole tissue became wilted within 10 days after inoculation. Twenty-four cultivars showed moderate resistance and twelve were resistant to bacterial wilts. In an evaluation of 73 major commercial cultivars, 'Lilyance', 'TP-7', 'Choice', 'Dadaki', 'Akiko', 'Redstar', 'Match', 'B-blocking', 'Magnet', 'Support', 'Friend' and 'Special' were found to have a high level of resistance to bacterial wilts of tomatoes.

• Korean Security Journal
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• no.20
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• pp.229-248
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• 2009

This research is looking for the private security industry and diagnostic issues and enable our strategy will be presented through SWOT analysis for the management environment of private security industry to ultimately contribute to the private security industry. Along, the purpose of this research is to want to reach key factors which affect the competitiveness of the private security industry. This study was to conduct literature research and surveys. And analyzing literature and data was collected. And determined the status of private security industry by conducted a comprehensive survey with 13 experts is causal. The question investigation hemisphere the question which harmonizes became accomplished in the center. Like this question analyzed the opinion of the identical research participant and 3 times was executed repetitively, and 2 to verify the data through multiple data as a basis for the SWOT analysis of the environment. Accordingly, the following conclusion emerges. First, the private security industry-related legislation will complement the systematic. This is the task of the public security authority and the relationship will be in the direction for improvement. Second, to develop strategies for diversification of products and services through the use of IT. This business what development security services and products based on IT advanced technology can provide a solution to maximize profits to large security companies and to all of the small companies. Third, it should seek ways to make exports that social safety net project based on security technology and capital of Kore for other Asian countries or developing countries in the world.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.91-100
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• 2009

The purpose of this study is to introduce the Levying Garage Option on Car Buyers which has become operative firstly in Korea, and to suggest the way to activate the system, hearing the view of Jeju residents with positive and negative function of parking. Levying Garage Option on Car Buyer is the system to apply a law for establishing garages to all of vehicles. Especially this is proposed to correct the disorder of Local street night parking, to improve the fine view of street, and to recover the original function of street to residents. To make this system successful there should be separate solutions at the densely built up area as a result of survey. This study conduct the Logistic Regression Analysis for and against the system. If the more residents approve the system, we should concern about the several solutions such as easing the distance between the garage and street, regulating, and special plan for an apartment house, etc. The suggestions are as follows. First, the policy needs to ease the distance between the garage and street gradually. Second, the Jeju government need to offer the residents the incentive such as reduce or exempt the tax and make them establish the private parking lot with supplying the low interest loan. Third, there should be connected with the project to break up the fences of their houses.