• Steel and Composite Structures
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• v.28 no.6
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• pp.671-679
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• 2018

The paper is devoted to the stability analysis of a simply supported five layer sandwich beam. The beam consists of five layers: two metal faces, the metal foam core and two binding layers between faces and the core. The main goal is to elaborate a mathematical and numerical model of this beam. The beam is subjected to an axial compression. The nonlinear hypothesis of deformation of the cross section of the beam is formulated. Based on the Hamilton's principle the system of four stability equations is obtained. This system is approximately solved. Applying the Bubnov-Galerkin's method gives an ordinary differential equation of motion. The equation is then numerically processed. The equilibrium paths for a static and dynamic load are derived and the influence of the binding layers is considered. The main goal of the paper is an analytical description including the influence of binding layers on stability, especially on critical load, static and dynamic paths. Analytical solutions, in particular mathematical model are verified numerically and the results are compared with those obtained in experiments.

• 전기의세계
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• v.19 no.1
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• pp.1-10
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• 1970

The foundation for the theoretical establishment of the linear motor lies in the investigation of the magnetic flux distribution in its airgaps. Generally speaking, the linear motor is similar, in the principle of its operation, to the general induction motor. However, there are great differences in the aspects of its structure and characteristics, especially, in the fact that the formation of its travelling magnetic field depends on the method of its winding. This paper is written in order to introduce the method of calculating the air gap magnetic flux distribution on the basis of its ampere-conductor in the case that 2 phase winding is applied on its open magnetic circuit iron core, and to present the results of investigation of the pulsation in its travelling fields. the first and second example of winding show the case of travelling magnetic field with the constant amplitude except the end region. The third example deals with the configuration of coil-side displaced outside the core and which produce the increased flux density at the ends, but, on the contrary, forms the pulsated travelling field.

• 전기의세계
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• v.15 no.5
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• pp.32-39
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• 1966

This voltage Regulator, which regulates voltage in different way from the conventional regulator, is constructed by circular-plate core type stators and controllers (are similar to rotor of conventional). The principle of this Voltage Regulator is based on the rotating magnetic field theory including peculiar homopolar and heteropolar concept. Comparing with the conventional induction regulator, this regulator need not to have short windings and can cancel armature reaction. Moreover, it is able to decrease the machine noise and control the phase of it freely. And it's efficiency can become more than 95% which almost the same as that of transformer's. By increasing numbers of cores of the same size, the output power can be increased, the insulation can be decreased and high Voltage can directly be connected because applied voltage is distributed to each core. This Voltage Regulator can be also used as a current regulator, a starter a induction motor and a phase transformer etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.777-780
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• 2005

The global consumption of aspheric surfaces will expand rapidly on the Electronics and Optical Components Information and Communications, Aerospace and Defense, and Medical optics markets etc. We must research on market, technology forecast and analysis of aspheric surfaces that is a principle step of ultra precision machine technology with a base one of optical elements. Especially, F-theta lens is one of the important parts in LSU(Laser scanning unit) because it affects on the optical performance of LSU dominantly. The core is most of important to produce plastic F-theta lens by plastic injection molding method, which is necessary to get the ultra-precision aspheric and non-axisymmetric machine processing technology.

• Smart Structures and Systems
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• v.23 no.5
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• pp.429-447
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• 2019

The present study analyzed free vibration of the three-layered micro annular/circular plate which its core and face sheets are made of saturated porous materials and FG-CNTRCs, respectively. The structure is subjected to magneto-electric fields and magneto-electro-mechanical pre loads. Mechanical properties of the porous core and also FG-CNTRC face sheets are varied through the thickness direction. Using dynamic Hamilton's principle, the motion equations based on MCS and FSD theories are derived and solved via GDQ as an efficient numerical method. Effect of different parameters such as pores distributions, porosity coefficient, pores compressibility, CNTs distribution, elastic foundation, multi-physical pre loads, small scale parameter and aspect ratio of the plate are investigated. The findings of this study can be useful for designing smart structures such as sensor and actuator.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.549-557
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• 2021

In this study, it is aimed to analyze the bending of porous sandwich plates using the four-variable shear deformation theory. The core of the sandwich plate is assumed to be functionally graded, and face sheets are assumed to be isotropic. The pore distribution of the sandwich plate is considered even and uneven type of porosity distribution. Displacement fields are defined with four variable shear deformation theory. Equilibrium equations of porous sandwich plates are derived from virtual displacement principle. An analytical solution is obtained by Navier's approach. Results are presented for uniformly and sinusoidally distributed loaded porous sandwich plates. Face sheet -core thickness ratio, porosity distribution, amount of porosity is investigated.

• Journal of the Daesoon Academy of Sciences
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• v.26
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• pp.77-110
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• 2016

The purpose of this article is to study on the Correlative linkage between the cosmic principle of birth-growth and contraction-recess and the Non action Tao. The split time between birth-growth and contraction-recess is the conflict between the Prior Time and Posterior Time as the Great Renewal. The cycle of this Chaotic Renewals is the cycle of a cosmic circulation as 129,600 years. In relation to the correlative linkage of function, Jeong-san Sangje governs all the beings of the universe by means of the cosmic principle birth-growth and contraction-recess. Also Jeong-san Sangje, using the Non action Tao governing all the beings of the universe and let them exist as the original selves. Thus, the two necessities are mutual interdependent and mutual complementary. In relation to the correlative linkage of substance, Jeong-san Sangje is included in the cosmic life which forms of all the existences. That is personal God of Jeong-san Sangje that is a part of the cosmic life. So that Jeong-san Sangje is included in the cosmic life, the basis of all the cosmic affairs. He is also subordinate to the cosmic principle but he simultaneously governs it. Jeong-san Sangje is trans-versal mediator between the cosmic principle and the cosmic life of Non action Tao, since it is the origin of his mind. To understand the nature of Jeong-san Sangje who becomes one with the cosmic life, the old causal way of thinking which inquires the timely order and seeks for causes and effects should be abandoned. The new way of thinking is thus different from the old one. The core of cosmic life is abstracted as the essence-energy and god-blood. This structure is similar to the cosmic principle of birth-growth and contraction-recess. The death is a kind of event caused by the depletion of the essence, and all beings could altered into the god. It also would be returned to the natural birth place of the cosmos, as it were, that can be called the 'Return to the Origin'. As the cosmos goes to the new epoch, humans have been living together with the cosmic principle. Now we can expect the Posterior Time to open to humans as cosmic life of Non action Tao.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.159-162
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• 2000

In his paper the principle of using coreless printed circuit board (PCB) based transformer in 2.3MHz, 12W class ZVS Forward DC-DC converter has been successfully demonstrated. With no core loss coreless PCB transformer and inductor are found to have favorable characteristics at high frequency operations. The maximum power conversion efficiency is 80% Even for high operating frequency an efficiency greater than 70% can be obtained with under 0.7% regulation error.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.33-34
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• 2006

The graft copolymer consisting of poly(N-isopropylacrylamide) (PNIPAAm) and single-stranded DNA was prepared. Interestingly, the copolymer was found to form nanoparticles above physiological temperature. We found that non-crosslinking aggregation of the nanoparticles was induced by the hybridization of the surface-bound DNA with the full-match complementary DNA, but not with one-base mismatch. The core material is not restricted to PNIPAAm; DNA-functionalized gold nanoparticle was found to show a similar aggregation induced only by the fully-complementary DNA, resulting in rapid color change within 3 min at ambient temperature. This methodology is general in principle and applicable for wide variety of clinical gene diagnosis.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.4
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• pp.182-194
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• 2009

The optical fiber subscriber receive communication system is multimedia home network core technology because it is providing the high-level data quality and service. Therefore, it is required to analyze and research this communication system. This paper presents the theoretical background of the optical fiber subscriber receive system for the purpose of understanding the optical communication system principle, and then explain the flow of signal process of each block divided for ASIC implementation.