• Journal of dental hygiene science
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• 제4권1호
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• pp.21-25
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• 2004

In modern times, children's trauma is increasing every year because of car accidents and life environment changes. There is a limit to prevent traumatic damage for oral cavity organization. The fundamental data of trauma treatment and prevention will be presented through the survey and analysis of traumatic teeth damage. I examined 113 patients from Oct. 4th, 2000 to Feb. 27th, 2004 at Dept. of Children's Dental Clinic, Kangnung National University. The results are as follows. (1) The trauma frequency of male subjects is higher than that of female at a rate of 2.05:1. The average age is 5.27 for men and 5.27 for women. The highest percentage of trauma patients is among 2 year old children. It is 21.2%. (2) A patient survey was taken at a trauma treatment hospital. On the first day 34.4% of the patients had come to receive treatment of their first set of teeth. However, after a week, 38.8% of the patients had received treatment on their permanent teeth. (3) As a result of falling, 59% of patients needing treatment on their first set of teeth. 55.1% of patients is permanent teeth. As a result of bump against physical solid, 26.6% of patients is the first set of teeth and 26.5% of patients is permanent teeth. (4) Teeth damage happened at home. 42.1% were male. 35.1% were female. According to trauma, 59.4% of teeth damage happened at home. 28.6% of permanent teeth damage happened at school or kindergarten. (5) According to trauma, the number of teeth damaged was in the first set of teeth are as follows: 56.3%, one-31.3%, three or four-6.3% each. For permanent teeth: two-46.9%, one-28.6%, four over-16.3% and three-8.2%. Over four teeth is larger number for permanent teeth. (6) 56% of first set of teeth patients and 43.4% of permanent teeth patients were male. 56.8% of first set of teeth patients and 43.2% of permanent teeth were female. Trauma happened to both male and female frequently in the first set of teeth. (7) Most of the tooth damage which was in the first set of teeth and permanent teeth was done to the upper jaw. 75% of patients are the first set of teeth. 63.8% of patients are permanent teeth. Trauma is very high in the two mid teeth of the upper jaw. (8) According to trauma survey, 30.2% is from impulse. 28.0% is from crown fracture, 14.7% is from depression. 8.9% is from concussion. 7.1% is from full dislocation of a joint. 2.2% of patients are extrusion. 1.8% is from displacement. According to teeth damage trauma, 35.8% is pulse in the first set of teeth. The breaking of the crown of a tooth happened a lot in permanent teeth. (9) According to data, 43.2% of teeth damage in the first set of teeth goes without treatment. In permanent teeth, it is 38.9%. After treatment, 22.0% of first set of teeth treatment requires a dental pulp treatment. In permanent teeth, which is used for temporary acid etching resin restoration.

• Structural Engineering and Mechanics
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• 제42권2호
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• pp.247-267
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• 2012

Calculating the displacements of retaining walls under seismic loads is a crucial part in optimum design of these structures and unfortunately the techniques based on active seismic pressure are not sufficient alone for an appropriate design of the wall. Using limit analysis concepts, the seismic displacements of retaining walls are studied in present research. In this regard, applying limit analysis method and upper bound theorem, a new procedure is proposed for calculating the yield acceleration, critical angle of failure wedge, and permanent displacements of retaining walls in seismic conditions for two failure mechanisms, namely sliding and sliding-rotational modes. Also, the effect of internal friction angle of soil, the friction angle between wall and soil, maximum acceleration of the earthquake and height of the wall all in the magnitude of seismic displacements has been investigated by the suggested method. Two sets of ground acceleration records related to near-field and far-field domains are employed in analyses and eventually the results obtained from the suggested method are compared with those from other techniques.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1146-1151
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• 2003

Pneumatic servo valve is an electro-mechanical device which change electric signals to a proper pneumatic signals, that is, flowrate and pressure. In this study, a pneumatic servo valve was designed and each simulation was conducted on any variation in the flowrate depending upon the magnetic force of the linear force motor and the displacement of the spool. And permanent magnet was used as a material for the plunger of the servo valve. Thereby, a low electrical power consumption type coil was desinged. And a modeling for the coil design was conducted by using the magnetic circuit. also, the feasibility of the modeling was verified by using a commercial magnetic field analysis program. The designed and fabrication of the spool and sleeve, position sensor, servo controller and the dynamic characteristic verified by the experiment.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.97-104
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• 2005

The seismic behavior of framed structure with Chevron-type bucking restrained braces were investigated and their behavior factors were evaluated following the procedure proposed in ATC-19 & ATC-34. Two types of structures, building frame systems and dual systems, with 4, 8, 12, and 16 stories were designed per the IBC 2000, the AISC LRFD and the AISC/SEAOC Recommended Provisions for BRBF. Nonlinear static pushover analyses were carried out to observe the plastic hinge formation and to identify the loads and the displacements at the yield and the ultimate states. Time history analyses were also carried out to compute the permanent displacement md the dissipated hysteretic energy. According to the analysis results, the response modification factors of model structures fumed out to be larger than what is proposed in the provision in low story structures, and a little smaller in medium-story structures. The dual systems, even though designed with smaller seismic load, showed superior static and dynamic performances.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제11권8호
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• pp.338-348
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• 2001

A hybrid self-hearing motor, which Is a functional combination of general permanent magnet (PM) motor and hybrid active magnetic bearing(AMB), was proposed a few years ago. In this paper the hybrid self-bearing motor is modified to a disk type, in which one of two magnetic hearings was substituted for a thin yoke to make the system more compact. An outer rotors in this self-hearing motor is actively controlled only in two radial directions while the ocher motions are passively salable owing to the disk-type structure. Main advantages of the proposed self-hearing motor are simple control mechanism, low power consumption and smart structure. Mathematical model for the magnetic force Is built wish consideration of the radial displacement of the rotor. The model helps us not only to design a levitation controller but also to expect the system performance. Some experimental results show good capability and feasibility of the Proposed self-bearing motor.

• Journal of Magnetics
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• 제15권2호
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• pp.64-69
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• 2010

This paper describes the development of a novel transverse flux linear motor (TFLM) excited by permanent magnets (PMs). It combines the advantage of two different TFLMs and produces high thrust with reduced normal force. The magnetic field is analyzed by combining the three-dimensional (3D) equivalent magnetic circuit network (EMCN) method with 2D finite element analysis. The experimental findings of the prototype motors are in good agreements with the analysis results, and demonstrate the potential of the proposed motor as a direct drive requiring relatively long displacement of a mover.

• The Journal of the Korean dental association
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• 제48권10호
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• pp.754-761
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• 2010

Horizontal root fractures are defined as those that involve cementum, dentin and pulp, comprising from 0.5 to 7% of injuries in permanent dentition on dental trauma. Diagnosis is made through clinical findings and radiographic exams, the latter frequently being limited by the position of the fracture line. Treatment varies according to the displacement of crown portion and vitality of the fragments. Authors describe clinical cases of maxillary right central incisor with horizontal root fractures in dental clinic, Jeju National University Hospital.

• Proceedings of the KIPE Conference
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.259-262
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• 2003

This paper is proposed a new linear actuator with the permanent magnet on the mover. This linear actuator is designed to produce the vibration of a osillator. In order to evaluate its dynamic performance, the equivalent coupling parameter between mechanical and electromagnetic equations of the linear actustor, which is considered the magnetic nonlinear phenomena, is analyzed by the finite element method and estimated the thrust, displacement and acceleration with the simualation values and the experimenta ones.

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1154-1156
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• 1999

This paper presents the novel fabrication of an electromagnetic micro actuator with a corrugated diaphragm and a flat one. The actuator consists of a Parylene diaphragm with a spiral copper coil and a permanent magnet. The cower coil is fabricated by electroplating and patterning. As the further works, the frequency response of the actuator are obtained by using a laser vibrometer and the static deflection of the actuator diaphragm are measure by using laser displacement meter. The corrugated diaphragm is expected to be better than the flat one with respect to the actuator performance.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기설비전문위원
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• pp.134-137
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• 2007

LMTT(Linear Motor-based Transfer Technology) 시스템은 항만 컨테이너 이송장치의 자동화 시템으로 기술적 포화상태에 이른 AGV (Automated Guided Vehicle)의 대체 수단으로 제안되었다. 본 논문에서는 PMLSM (Permanent Magnetic Linear Synchronous Motor)을 기본 구조로 한 LMTT에서 발생할 수 있는 레일과 차체간의 인척력 변화와 다양한 부하 중량에 대한 시스템 내부 변수의 변동에 적응할 수 있는 제어기 설계에 초점을 두었다. 그렇게 됨으로써 제어시 큰 방해요소로 작용하는 마찰력에 의한 백래쉬 및 데드존을 최소화하여 속응성 및 정밀도를 향상시키고자 하였다.