• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.238-241
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• 2006

The needs for strengthening and rehabilitation of the concrete bridges are a growing concern in many countries and has been emphasized in various researches and papers. Traditional external post-tensioning method using either steel bars or tendons is commonly used as a strengthening method. However, the method has some disadvantages such as stress concentration at the anchorages. Multi-stepwise thermal prestressing method is a newly proposed method for strengthening and rehabilitation of concrete girder bridges. Founded on a simple concept of thermal expansion and contraction of steel, the method is a hybrid method of external post-tensioning and steel plate bonding, combining the merits of two methods. In this paper, basic concepts on strengthening and rehabilitation of concrete girder are presented and an illustrative experiment is introduced.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.123-124
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• 2009

This research is a part of the comprehensive research project to develop the optimized UHPC precast deck system applying to durable and cost-effective hybrid cable stayed bridge. Longitudinally prestressed ribbed section is proposed to make the best use of a advantage of the ultra high performance concrete and the design concept is presented to decide the sectional property.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.73-79
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• 2008

Result that study magnet nerve curer for treatment induced current generation and current of ion for development in main point incontinence, prostate, sphincter, nervous system, rigidity, headache, retrogression arthritis, ligament damage, Rheumatism arthritis, peripheral nerve etc., can classify by 4. Embodied do first, full bridge magnet occurrence chapter, and communication with PC is available, confirmed various action loops an experiment. Could confirm correct treatment probe second, woman and man disease person. Third, derived so that healing may be possible naturally by addition of apron form according to disease. Because composition of finally, treatment probe composes by act of negative plate form, manufacture is easy and cooling designed for easy direction. More superior result of cooling appeared than existing in incidental and ingredients, cooling efficiency, composition, complexity, convenience etc. that expense and composition manufacture very straightforwardly and experimental by 2 - Tank ways.

• Journal of the Korean Ceramic Society
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• v.19 no.3
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• pp.199-204
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• 1982

Bowl 형태의 일본산 Nagano 점토에 대한 분류 및 특성화 연구를 하였다. 결정입자 크기를 1$\mu$ 이하로 침강분리 시킨후 전자현미경으로 결정형태를 관찰하였다. 아울러 결정형태, 구조적 결함 및 intercalation 반응성의 상호관계를 검토하기 위하여 tube 형태의 한국산 halloysite 및 plate 형태의 kaolinite를 비교 조사하였다. 특이한 Bowl 형 Nagano 점토는 tube형 halloysite와 화학 반응성에서 동일하여 극성 내지는 hydrogen bridge 결합을 하는 guest 분자와 반응하여 층간삽입 화합물을 형성 하였다. 화학반응성에 따른 점토분류방법에 의해 Nagano 점토가 halloysite임을 밝혔으며 아울러 결정의 형태는 반응성에 영향을 미치지 않음을 알 수 있었다.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.219-223
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• 1995

Since the mid of 1970's, the construction of infrastructure has been booming and accelerating to keep up with rapid economic growth. Fast achievement of most construction activities has caused unfavorable effects of civil petitions associated with damages and nuisances due to last hasty works. it is well known that the falling down of Sungsoo bridge and the collapse of Sampoong department and other structures have occurred because of the construction not conforming with the specification, and thereby incurred enormous loss of life and property. Now a days. a periodic inspection and maintenance have been strongly interested on aged RC structures, of repair and reinforcement technique in the country, most repairing and reinforcing works have been performed on the basis of the guidance of few experienced local company in this field.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.175-176
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• 2010

Current Bridge Specification for Highway Bridges adopts a simplified method to determine sectional forces of abutment wing by diving its area into four sections. This simplified method was developed when numerical analysis was not mature and computer resources were expensive. It has been criticized that the simplified method produces conservative results. This study evaluates the problem of current design practice to improve the design guideline for abutment wing.

• Journal of Industrial Technology
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• v.16
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• pp.123-129
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• 1996

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. In order to obtain the natural frequency by the presented method, the first step to take is to obtain the deflection influence surfaces. In design and analysis of any structure, the first step to be taken is to obtain this deflection influence surfaces. Any method can be used for this purpose. Then using this surfaces, deflections, slopes, moments, shears, and natural frequencies can be obtained by differentiating either the continuous function or discrete function defined at certain points. The merit of the presented method is that the natural frequency can be obtained by the deflection influence surfaces obtaining which is the first step in structural analysis.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.124-129
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• 2010

For the industrial printing applications, the stability of the piezo-driven inkjet printhead is a major requirement. In this paper, we focused on the failure modes of the inkjet printhead and realized a method to detect and repair them at high speed. The printhead monitoring is performed by detecting the residual vibration of the actuating plate using the self- sensing capability of the piezoelectric material. To measure the channel acoustics and to identify the malfunctioning nozzle, we devised the bridge sensing circuitry and failure detection algorithm. The residual vibration signals can be affected by the boundary conditions of the channel acoustics, so it is possible to identify the failure causes by analyzing the monitoring signals. Therefore it is also possible to apply a proper restoring process to the defective printhead. The experimental results show that this method is effective in improving the reliability of the industrial printing.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.601-608
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• 2003

A new type of bridge superstructures referred to as Steel-confined Prestressed Concrete Girder (SCP Girder) was developed, which is composed of concrete, steel plate, and prestressing tendon. The girder may maximize structural advantages of these components : thus, long span bridges with low height girder may be constructed. For the effective design and fabrication of the girder, the design software program was developed and the process of fabrication established. The experimental girder designed using the program was manufactured in actual size to confirm the fabric ability of the girder. Propriety of design, structural safety, and applicability of the girder were verified through the load test.

• Journal of Mechanical Science and Technology
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• v.20 no.11
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• pp.1942-1949
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• 2006

Typically, condensate forms as droplets on the fin surfaces and may bridge the space between the fin surfaces. This is due to the dry characteristics inherent to the fin surface. The droplets increase the air-side pressure drop. In the case of high air velocities, these droplets may be blown off the fins and entrained in the air stream. To minimize the formation of condensate droplet, the wet ability of the fins must be improved. The carry-over velocity is affected by fin surface characteristics. To avoid carry-over in the air conditioner having the highest air velocity of 1.5 m/sec, the dynamic contact angle (DCA) should be at least lowly under $60^{\circ}$.