• Journal of the Korean Magnetics Society
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• v.13 no.3
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• pp.127-132
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• 2003

Natural convection of a magnetic fluid is different from that of Newtonian fluids because magnetic-body force exists in addition to gravity and buoyancy. In this paper, natural convection of a magnetic fluids (W-40) in a cubic cavity was examined by experimental method. One side wall was kept at a constant temperature (25 $^{\circ}C$), and the opposite side wall was also held at a constant but lower temperature (20 $^{\circ}C$). The magnetic fields of various magnitude were applied up and down by permanent magnets. We measured temperatures at 5 points which are the most suitable places in cavity by the analysis record. The thermo-sensitive liquid crystal film (R20C5A) was utilized in order to visualize wall-temperature distributions. Several kinds of experiments were carried out in order to clarify the influence of direction and intensity of magnetic fields on the natural convection. It was found that the natural convection of a magnetic fluids could be controlled by the direction and intensity of the magnetic fields.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.211-212
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• 2019

It is possible to realize the concept of long-life housing by utilizing the wall piping infill system. However, when using the wall piping infill system, there is no detailed standard in Korea. Problems may occur in actual use. In this study, we use the results obtained from the performance test method as a basic data. Since the load resistance test of the toilet is not available in Korea, GB 6952 (Sanitary wares) of China is applied. According to the experiment of load resistance of the toilet in this study, the strain recovery ability was good. However, it is not possible to exclude the possibility of permanent deformation of the toilet seat due to long - term repeated loading. Therefore, it is necessary to consider the stiffness enhancement of the wall (steel frame) to the fixing part when installing the toilet in the wall pipe infill system.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.1
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• pp.88-92
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• 2010

We propose a new design of the hybrid-magnet wheel to make it possible for a mobile robot to be attached to the vertical plane and be in motion. In the new suggested design, a permanent magnet is utilized to enhance the adhesive force, while an electromagnet is adopted to reduce the magnetic field and the adhesive force for detaching easily. To analysis the performance of the robot, 3 dimensional finite element analysis is executed using commercial electromagnetic analysis program, Maxwell. The results show that the adhesive force is reduced effectively by the electromagnet in the new designed robot system.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.90-94
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• 2002

This paper is related to remote meter-reading using magnetic sensor. Scan system which is developed recently has week point of temperature, humidity, dust, oscillation To solve these problems, this study used magnetic action to measure the consumption of gas. Gas consumption was detected by interaction of a permanent magnet and hall element. Permanent magnet was pasted on rolling change-gear in normal gas meter and hall sensor was pasted on the external wall of normal gas meter. This experiment proved high accuracy and wasn't influenced by temperature, humidity, oscillation and dust

• Archives of Craniofacial Surgery
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• v.19 no.4
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• pp.264-269
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• 2018

Background: Orbital resorbable mesh plates are adequate to use for isolated floor and medial wall fractures with an intact bony buttress, but are not recommended to use for large orbital wall fractures that need load bearing support. The author previously reported an orbital wall restoring surgery that restored the orbital floor to its prior position through the transnasal approach and maintained temporary extraorbital support with a balloon in the maxillary sinus. Extraorbital support could reduce the load applied on the orbital implants in orbital wall restoring surgery and the use of resorbable implants was considered appropriate for the author's orbital wall restoring technique. Methods: A retrospective review was conducted of 31 patients with pure unilateral orbital floor fractures between May 2014 and May 2018. The patients underwent transnasal restoration of the orbital floor through insertion of a resorbable mesh plate and maintenance of temporary balloon support. The surgical results were evaluated by the Hertel scale and a comparison of preoperative and postoperative orbital volume ratio (OVR) values. Results: The OVR decreased significantly, by an average of 6.01% (p<0.05) and the preoperative and postoperative Hertel scale measurements decreased by an average of 0.34 mm with statistical significance (p<0.05). No complications such as buckling or sagging of the implant occurred among the 31 patients. Conclusion: The use of resorbable mesh plate in orbital floor restoration surgery is an effective and safe technique that can reduce implant deformation or complications deriving from the residual permanent implant.

• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.312-331
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• 1991

Top-down Method of basement construction technique has been applied for building of the deep basement car park the close proximity of priceless historic buildings in LONDON. Numerical analysis for the prediction of ground movement of the surrounding buildings was performed in order to compare the field data at the various stages of excavation and support. The predicted results from the elasto-plastic analytical method were compared with the observed data and the agreement is very satisfactory. It may be concluded that the system of diaphragm wall supported by the permanent base slabs (Top-Down Method) was proved to be the most effective technique in terms of reducing any critical damage to the surrounding buildings.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.251-258
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• 2008

The use of reinforced earth walls in permanent structures is getting it's popularity. Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, during their service period. In this investigation, the effect of preloading in reducing long term residiual deformation of back-to-back reinforced soil wall under sustained and/or repeated loading enviormentment using a series of reduced-scale model tests. It is found that the preloading technique can be an effective means of controlling residual deformations of reinforced soils under varisous loading conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.134-138
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• 1995

The reinforced concrcte structure were once belicved to have permanent durability. However, it is now spoiled by durability failure caused by the corrosion of embeded steel reingorcement carbonation. alkali-aggregate reaction and salt attack Recently. salt damage has been also spreading. Salt damage is found in concrete structures built using seasands or certain admixtures containing calcium chlorides and in coastal structures frequently caught in seawater spray or blown by seawind It is the aim of this study to investigate the performance and application of new repair system for the exterior wall according to the durability improvement in the RC structures.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.197-199
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• 2011

To utilize the Top-Down construction method, it is required to analyse building area, floors, and soil conditions to choose the three basic elements of retaining wall, base column, and floor structure. The purpose of this research is to compare the methods of Top-Down with other construction methods. The research method is to analyse the project conditions of Top-Down project cases. The aim is to develop a method of selecting alternatives, considering construction characteristics, work schedule, supporting methods, foundation types.

• Journal of the Korean Society for Nondestructive Testing
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• v.5 no.2
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• pp.42-48
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• 1986

Electromagnetic - Acoustic Transducers for the inspection of tubes were developed using permanent magnets and induction coils. The propagation velocity of ultrasonic waves in a tude wall was measured by the transducers. The position of a flaw in a tube and the relative size of flaws with different size were measured.