• Journal of the Korea Concrete Institute
• /
• v.19 no.4
• /
• pp.433-439
• /
• 2007

The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.3
• /
• pp.263-267
• /
• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• Proceedings of the KWS Conference
• /
• 2010.05a
• /
• pp.65-65
• /
• 2010

In shipbuilding industry, welding position are usually flat and vertical position at the erection stage. Application of SAW and EGW for these positions makes it possible to achieve enhanced productivity and high quality. But owing to their large size and weight it is difficult to apply these techniques in short and narrow regions. To overcome this problem, our company developed light weight and compact size 4-axis welding carriage which perform 3D weaving. The purpose of this study is to explain the development and application of intelligent welding carriage using 3D weaving pattern that can fill a large amount of welds and thereby making it possible to achieve high quality of welding. This study shows 3D weaving pattern, development of weaving database, and skill of adaptive control response for the variable gap. Also, it shows the results of procedure qualification test for the AH-grade steel when applied to the intelligent welding carriage.

• Journal of Arbitration Studies
• /
• v.26 no.2
• /
• pp.27-44
• /
• 2016

The use of program formats has slowly but surely developed into an important component of the television industry. This article examines the surprising gap between the constantly growing, multi-billion-dollar trade of program formats and their unclear and contradictory legal treatment. From both the social and commercial standpoints, television formats are valuable creations. Understanding the two products, the paper and program stages, of a television format and their respective markets, is fundamental to discussions of its legal protection. Interestingly, under current law, the less-developed stages of the process (program ideas and paper formats) are awarded more protection than the aired program format, which accumulates higher levels of investment, creativity, and expression. Internal industry mechanisms, such as vertical integration, damage to reputation, and industry institutions, exist in both markets and are still able to control and influence members' behavior to some extent. However, while the influence of internal industry mechanisms is still strong in the paper format market, in the program format market, which continues to grow, such mechanisms have weakened, amplifying the importance of a clear legal system. The absence of protection will certainly not completely eliminate the production of new program formats. However, these factors do not add up to a case against protection. The changes in the program format market in the last two decades support the theory that the overall effect of providing legal protection for TV formats would promote beneficial competition and encourage more original creations. The underlying question for television formats should not be whether to protect but rather how.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.11
• /
• pp.971-978
• /
• 2016

Recent trends in miniaturization and lightness in portable electronics parts have driven developments in subminiature screws. This study aims to investigate the thread rolling process of a subminiature screw with an outer diameter and pitch of 1.0 and 0.25 mm, respectively. Finite element (FE) analyses were performed for the thread rolling process of symmetric and asymmetric screw threads. Through FE analyses, various process parameters, such as the horizontal and vertical die gap and the rolling stroke, were investigated in terms of the forming accuracy. The material flow characteristics in the thread rolling process of the symmetric and asymmetric screws were also discussed, and the relevant process parameters were determined accordingly. These simulation results were then reflected on real thread rolling processes, from which the symmetric and asymmetric screws could be formed successfully with allowable dimensional accuracy.

• Applied Microscopy
• /
• v.44 no.1
• /
• pp.21-29
• /
• 2014

Retinal glial responses to hypertensive glaucomatous injury were spatiotemporally surveyed. Retinas as a whole or vertical sections were processed for anti-glial fibrillary acidic protein (GFAP), anti-Iba1, anti-nerve growth factor (NGF), and anti-tumor necrosis factor (TNF)-${\alpha}$ immunohistochemistry for confocal microscopic analyses. The optic nerve head of paired controls was processed for electron microscopy. GFAP positive astrocytes appeared in the nerve fiber layer in the glaucomatous and control retinas, changing from fine protoplasmic to stout fibrous parallel to glaucomatous duration. Iba1 positive microglia appeared in both retinas, and enormous reaction appeared at the latest glaucomatous. M$\ddot{u}$ller reaction detected by GFAP reactivity expanded from the end feet to whole profile following to duration in the glaucomatous. NGF reactivity expended from the end feet to the proximal radial processes of the M$\ddot{u}$ller cells in both retinas according to glaucomatous duration. TNF-${\alpha}$ immunoreactivity in the nerve fiber layer was stronger in both the glaucomatous and controls than in the normal, and exceptionally at the latest glaucomatous was even lower than the normal. The astrocytes in the optic nerve head are interconnected with each other via gap junction. These results demonstrate that astrocyte reaction propagates to the contralateral via physical links, and TNF-${\alpha}$ is correlated with NGF production for neuroprotection in response to hypertensive glaucomatous injury.

• Nuclear Engineering and Technology
• /
• v.48 no.4
• /
• pp.847-858
• /
• 2016

An overview is given on the work of the Laboratory of Nuclear Energy Systems at ETH, Zurich (ETHZ) and of the Laboratory of Thermal Hydraulics at Paul Scherrer Institute (PSI), Switzerland on tight-lattice bundles. Two-phase flow in subchannels of a tight triangular lattice was studied experimentally and by computational fluid dynamics simulations. Two adiabatic facilities were used: (1) a vertical channel modeling a pair of neighboring sub-channels; and (2) an arrangement of four subchannels with one subchannel in the center. The first geometry was equipped with two electrical film sensors placed on opposing rod surfaces forming the subchannel gap. They recorded 2D liquid film thickness distributions on a domain of $16{\times}64$ measuring points each, with a time resolution of 10 kHz. In the bubbly and slug flow regime, information on the bubble size, shape, and velocity and the residual liquid film thickness underneath the bubbles were obtained. The second channel was investigated using cold neutron tomography, which allowed the measurement of average liquid film profiles showing the effect of spacer grids with vanes. The results were reproduced by large eddy simulation + volume of fluid. In the outlook, a novel nonadiabatic subchannel experiment is introduced that can be driven to steady-state dryout. A refrigerant is heated by a heavy water circuit, which allows the application of cold neutron tomography.

• Journal of Biomedical Engineering Research
• /
• v.17 no.1
• /
• pp.85-92
• /
• 1996

A monoleaflet polymer artificial heart valve which showed the remarkable improvement in pressure drop compared with other types of artificial valve was designed to minimize the deflection in vertical direction and the displacement of the valve tip in horizontal direction obtained by using finite element method as the location of the supporting members of the valve frame changed stress distribution change was also studied on each model generated by changing the distance between the frame and supporting members. It was found that by using the valve tip horizontal displacement the minimum valve thickness could be obtained in order to prevent the gap between the valve tip and the frame wall.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.5
• /
• pp.135-141
• /
• 2020

This paper summarizes the data of a monopole antenna with a sleeve structure that can be applied in various ways. Sleeve monopole antennas have broadband characteristics and are used for multi-frequency applications. The sleeve monopole antenna is composed of a vertical conductor, which is a radiator, and a sleeve having the same structure as a coaxial cable. The sleeve acts as a radiator and an open stub. The length of the sleeve should be 1/3~2/3 of the total length of the antenna. A monopole antenna having a sleeve structure is applicable to a vehicle wiper antenna. In addition, the case of applying this antenna to a broadband sleeve antenna using a loading coil, a broadband printed sleeve monopole antenna for an ISM band, a gap sleeve and a double sleeve, and a UWB planar monopole antenna using half cutting was summarized and analyzed in terms of structure and broadband.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.7
• /
• pp.393-400
• /
• 2003

In this paper we deal with the virtually zero power control for the rigid rotor with radial suspension by the permanent magnetic bearing and axial suspension by electromagnetic bearing. The purpose of the virtually zero power control is to reduce the power consumption of the electromagnetic bearings. The axial active force is expressed by the normal second order equation which has only one degree-of-freedom. The virtually zero power control structure has two schemes. One is the coil control current integrator which is used to make the convergence of the control current to a range which is very close to zero. By using the current integrator the DC component which is included in the control current is eliminated, thus the control current converges to a range which is close to zero. The other is normal PD control loop which is used to make the rotor reach to stable equilibrium point and to maintain air gap so that the axial force produced by radial permanent magnet always balances the total weight of the rotor and its load. First we show a simple mathematical plant model and the virtually zero power (VZP) control blocks. Second, we investigate the theoretical feasibility and the stability of the proposed virtually zero Power control levitation system with PD feedback loop by using linear control theory Finally we show the effectiveness of the proposed control method to reduce the power consumption by simulations.