• Fire Science and Engineering
• /
• v.18 no.4
• /
• pp.57-63
• /
• 2004

We investigated heat properties of connection terminal in residual current protective devices(RCD) according to contact pressure for low voltage appliance. And we analyzed voltage and current waveform and oxide propagation when the poor-contact happened between terminal and wire. When contact pressure between terminal and connection wire was not applied, the heat was generated and an oxide was formed on the surface of the wire. The temperature of the insulation surrounding terminal was ascended sharply by poor-contact, micro-sparks and continuous arc sound happened in interior terminal. When the poor-contact by vibration occurred inner conductor of terminal and wire, an oxide was propagated on contact surface and the temperature was increased at 869℃. Thus, we found that the risk of electrical disaster is high in terminal and connection wire parts.

• Journal of the Korean Magnetics Society
• /
• v.17 no.2
• /
• pp.55-59
• /
• 2007

Co-based amorphous magnetic wire with a diameter of $125{\mu}m$ and a length of 40 mm was used as an inner conductor of a coaxial cable to construct a magnetic sensor. Sensor characteristics was measured up to 3 GHz with applied up to 60 Oe by using network analyzer. Frequency dependence of impedance for this sensor was very close to the impedance resonant pattern of transmission line and 250 MHz was obtained as a 1/4 wavelength without external magnetic field. Large impedance change was measured in the magnetic field range between 0 Oe and 1 Oe, which was influenced by permeability change of magnetic amorphous wire. Because ${\Delta}Z/{\Delta}H$ value of $300{\Omega}/Oe$ was obtained at 0.1 Oe, this coaxial cable with amorphous wire can be useful as a magnetic sensor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.8
• /
• pp.790-796
• /
• 2011

The system which is exposed in the impact range of High-altitude Electromagnetic Pulse(HEMP) may get serious damage because HEMP has a very large electric field value, a very fast rise-time, and so on. Electromagnetic analysis should be performed for signals coupled to the opening or cables of the system prior to derive the system design specifications in order to protect the system against HEMP adequately. In this paper, we analyzed the HEMP coupled signals for the coaxial cable which is generally used to transmit and receive video or RF signals and compared the coupled signal of the one wire with that of the inner conductor of a coaxial cable to confirm the decreased effect of HEMP by the shield. The coaxial cable is analyzed by the external and internal region of the shield separately. For the external region of the coaxial cable, general scattered equation was applied to calculate currents on the surface of the shield and for internal region of the coaxial cable, chain matrix algorithm is used. To verify this paper the analyzed results were compared the results of the existing paper and the two results have good agreements.

• Journal of the Korean Society of Costume
• /
• v.62 no.4
• /
• pp.32-45
• /
• 2012

The purpose of this research is to better understand the Dongmyo, the Eastern Shrine of GuanYu and the military costumes of the Joseon period andto develop different cultural contents. By studying relevant literature, confirmations were made about the various types of costumes and their historical changes. During the reign of King Yeongjo, the ceremonial conductors often wore armors, and the king wore a different military costume. During the reign of King Jeongjo thereafter, the ceremonial costumes were codified in the book, the Chun-gwan tonggo(General Outline for the Ministry of Rites), along with the costumes for the musicians and lower officials. However, the military features were weakened in the late Imperial Joseon years. In terms of costumes, it would be best today to restore the ceremonies of the Shrine of Guan Yu during the period of King Jeongjo. All the costumes for different figures of the Shrine are clearly confirmed, and by emphasizing the main features of the ceremonials of the Shrine, it is possible to differentiate the ceremony from other restoration activities in Korea. For the Guan Yu statue, the hat is square shaped and decorated with nine bead strings, it is dressed with a red dragon coat and a violet inner coat. This study presents methods for the restorations of the original costumes for the individual figures of the ceremonials, with necessary theoretical explanations. The king wears the lamella gold armor, while different ceremonial officials wear differentiated armors according to their different ranks. All the civil and military officials who attend the ceremony wear military clothes with horse's mane hats and swords. The musical conductor and directors are expected in armors and participating musicians also have to wear armors according to the Akhak Gwebeom (Basics of Music).

• School Mathematics
• /
• v.18 no.1
• /
• pp.85-103
• /
• 2016

This study was to find characteristics of argumentation derived from a discourse in a math-gifted 5 grade class, which was held for finding a Pick's formula using Geoboard function of TI-73 calculator. For the analysis, a video record of the class, transcript of its voice record, and activity paper were used as data and Toulmin's argument schemes were applied as analysis standard. As a result of the study, we found that the graphing calculator helped the students to create an experimental environment that graphing a grid-polygon and figuring out its area. Furthermore, it also provided a basic demonstration through 'data->claim' composition and reasoning activities which consisted of guarantee, warrant, backing, qualifier and refutal for justifying. The basic argumentation during the process of deriving the Pick's theorem by the numbers of boundary points and inner points was developed into a 'collective argumentation' while a teacher took a role of a conductor of the argumentation and an authorizer on the knowledge at the same time.

• Journal of Digital Convergence
• /
• v.13 no.7
• /
• pp.413-422
• /
• 2015

This study is conducted for the purpose of conceptualizing a choral communication model. first, the musical communication models analyzed to know how it can apply in the choral music. As a result, we take the music communication is the interaction between composers, performers and audience. But the choral music have properties not found in the general music. The choral music is the need for internal communication process before performing music. First, the conductor is to interpret the music. Next, choral members are shared the interpretation of music. This internal communication be conducted properly, musical communication with the audience will be successful. The trial model provided for in this study will be a guideline for successful communication in the choral music, theoretically or practically.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.2
• /
• pp.119-126
• /
• 2008

In this paper, the loop coupling model for the analysis of end launcher rectangular waveguide adapter are proposed. The formula of input impedance from this model are presented. The influence of propagation mode and higher modes in rectangular waveguide are analyzed and design parameters of the end launcher adapter are investigated. The computational results between the proposed theoretical analysis and the previous papers are compared and are verified by HFSS. The end launcher rectangular waveguide adapter consists of the coupling geometry which is connected the inner conductor of $50{\Omega}$ coaxial line through into the 17.6mm feeding loop in a WR90 commercial waveguide, and the VSWR is maximum 2.0 over operating frequency from 7.5GHz to 10.6GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.3
• /
• pp.303-312
• /
• 2009

In this study, a waveguide system for focusing the electric field is presented to emit the microwave-driven plasma visible light. This system consists of a magnetron for the microwave power supply, the waveguide section for power propagation, and the mesh-type cavity reactor. The quartz bulb containing a dose of sulfur powder and buffer gas Ar is located in the reactor, and forced by the strongly concentrated electric field for generating and exciting the sulfur plasma. That is, the conductor tips are loaded on each inner wall of the waveguide and the reactor, and then the plasma bulb is positioned between the tips, hence focusing the strong electric field on the bulb. Furthermore the waveguide section is designed for minimizing the degradations of matching characteristics according to the variations of the electrical conductivities of plasma at the transitory phase for plasma generation, hence providing the stable operation. Finally, the 2.45 GHz aluminum waveguide system is constructed, and then experiments for emitting the visible light are performed by using 400 W-class magnetron, showing the validity of designed system.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.3 no.1
• /
• pp.23-28
• /
• 1999

Rectangular waveguide slot antenna which has simple structure, high efficiency, high trust and small size, is extending in a field of application such as many Radar and Microwave communication. A slot cut into a wall of waveguide is propagated electromagnetic wave to free space it interrtupts the flow of current inner conductor of waveguide. Therefore incident of slot, cutdepth, width, length, i.e. are important parameter of characteristic change of the slot antenna. Result from difficulty of theoretical analysis about slot frequently experimental measured data useful design and manufacture have been accomplished. In this paper, we find the suitable method of analysis that compare two analysis results with measured result of established literature - admittance of slot be solved by propagated power from electric field distribution of slot and mode current computation and accomplishment of computable chart which hasresonant length and cutdepth, incident of slot, i.e. and use the HFSS which applyed finite-element method obtain equal slot analyed method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.37-43
• /
• 2017

This review investigates the basic principle of physical interactions and failure mechanisms introduced in the materials and inner parts of semiconducting components under electromagnetic pulses (EMPs). The transfer process of EMPs at the semiconducting component level can be explained based on three layer structures (air, dielectric, and conductor layers). The theoretically absorbed energy can be predicted by the complex reflection coefficient. The main failure mechanisms of semiconductor components are also described based on the Joule heating energy generated by the coupling between materials and the applied EMPs. Breakdown of the P-N junction, burnout of the circuit pattern in the semiconductor chip, and damage to connecting wires between the lead frame and semiconducting chips can result from dielectric heating and eddy current loss due to electric and magnetic fields. To summarize, the EMPs transferred to the semiconductor components interact with the chip material in a semiconductor, and dipolar polarization and ionic conduction happen at the same time. Destruction of the P-N junction can result from excessive reverse voltage. Further EMP research at the semiconducting component level is needed to improve the reliability and susceptibility of electric and electronic systems.