• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.6
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• pp.601-607
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• 2015

A set of novel silicon controlled rectifier (SCR) devices' characteristics have been analyzed and verified under the electrostatic discharge (ESD) stress. A ring-shaped diffusion was added to their anode or cathode in order to improve the holding voltage (Vh) of SCR structure by creating new current discharging path and decreasing the emitter injection efficiency (${\gamma}$) of parasitic Bipolar Junction Transistor (BJT). ESD current density distribution imitated by 2-dimensional (2D) TCAD simulation demonstrated that an additional current path exists in the proposed SCR. All the related devices were investigated and characterized based on transmission line pulse (TLP) test system in a standard $0.5-{\mu}m$ 24 V CDMOS process. The proposed SCR devices with ring-shaped anode (RASCR) and ring-shaped cathode (RCSCR) own higher Vh than that of Simple SCR (S_SCR). Especially, the Vh of RCSCR has been raised above 33 V. What's more, their holding current is kept over 800 mA, which makes it possible to design power clamp with SCR structure for on chip ESD protection and keep the protected chip away from latch-up risk.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.309-315
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• 1998

This paper describes an 8b 52 MHz CMOS subranging analog-to-digital converter (ADC) for Integrated Services Digital Network (ISDN) applications. The proposed ADC based on the improved time-interleaved architecture removes the holding time which is typically observed in the conventional double-channel subranging ADCs to increase throughput rate. Moreover, the ADC employs the interpolation technique in the back-end subranging ADCs far residue signal processing to minimize die area and power consumption. The fabricated and measured prototype ADC in a 0.8 um n-well double-poly double-metal CMOS process typically shows a 52 MHz sampling rate at a 5 V supply voltage with 230 mW, and a 40 MHz sampling rate at a 3 V power supply with 60 mW power consumption.

• Journal of Adhesion and Interface
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• v.18 no.4
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• pp.166-170
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• 2017

In this study, acrylic rubber pressure sensitive adhesives was polymerized with 2-ethylhexyl acrylate, styrene, butadiene, 2-hydroxyethyl acrylate, and acrylic acid by controlling the initiator content. The initial tackiness, peel strength, holding power, and heat resistance of the PSAs were investigated by changing the content of tackifier and curing agent. The results showed that the initial tackiness and peel strength increased as the content of tackifier increased, whereas the holding power decreased. Also, the results exhibited that that the initial tackiness, peel strength, and heat resistance decreased as the content of curing agent increased, whereas the holding power and decreased.

• Elastomers and Composites
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• v.34 no.4
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• pp.360-365
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• 1999

In this study, the blends of acrylic quaternary polymer (PEBEV) which was co- polymerized from 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA) and ethyl acrylate (EA), vinyl acetate (VAc), and poly(vinyl chloride-co-vinyl propionate) (PVCVP) were prepared by solution blending. Pressure sensitive adhesive (PSA) properties of PEBEV/PVCVP blends were compared with those of PEBEV/poly(vinyl chloride-co-vinyl acetate) (PVCVAc) blends. Compatibility of PEBEV/PVCVP was better than that of PEBEV/PVCVAc. Tackiness of both blend systems were similar, but holding power began to decrease at 15wt% or higher PVCVAc contents in PEBEV/PVCVAc blends. On the other hands, holding power of PEBEV/PVCVP increased as the contents of PVCVP increased. Failure modes of the blends were adhesive failure except 5wt% of PVCVP was blended.

• Nuclear Engineering and Technology
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• v.41 no.2
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• pp.187-198
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• 2009

In this paper, three power ramp tests performed on high burn-up Re-crystallized Zircaloy2 - UO2 BWR fuel rods (56 to 63 MWd/kgU) within the SCIP project are simulated with METEOR and ALCYONE 3D. Two of the ramp tests are of staircase type up to Linear Heat Rates of 420 and 520 W/cm and with long holding periods. Failure of the 420 W/cm fuel rod was observed after 40 minutes. The third ramp test consisted of a more standard ramp test with a constant power rate of 80 W/cm/min up to 410 W/cm with a short holding time. The tests were first simulated with the METEOR 1D fuel rod code, which gave accurate results in terms of profilometry and fission gas releases. The behaviour of a fuel pellet fragment and of the cladding piece on top of it was then investigated with ALCYONE 3D. The size and the main characteristics of the ridges after base irradiation and power ramp testing were recovered. Finally, the failure criteria validated for PWR conditions and fuel rods with low-to-medium burn-ups were used to analyze the failure probability of the KKL rodlets during ramp testing.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.8
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• pp.459-466
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• 2000

In this paper, we propose an attitude controller for an unstructured object using CMG(Control Moment of Gyro) subsystem, which has a stabilizer function. The CMG subsystem consists of one motor for spinning the wheel and the other motor for turning the outer gimbal. While the wheel of CMG subsystem is spinning at high speed, applying force to the spin axis of the wheel leads the torque about the vertical axis. We utilize the torque to control the attitude of object in this study. For the stabilizer function, in additiion, holding the load at the current position, the power applied to the gimbal motor of CMG will be cut, which result in the braking force to stop the load by gyro effect. However, due to the gear reduction connected to outer gimbal, slow load motion cannot generate the braking force. Thus, in this study, we are willing to make a holding force by applying control power to the gimbal motor from the signal of piezoelectric gyroscopic sensor that detected the angular velocity of the load. These two features are demonstrated in experiment, carrying a beam with crane. As a result, load was started to rotate by controlling gimbal positiion and was stopped by turning off the gimbal power. Moreover, slow movement of the load was also rejected by additional control with gyroscopic sensor.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.81-90
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• 1993

The Surfactants composed of acylated aterocollagen which is produced by the acylation of the side chain amino radicals of aterocollagen with an aliphatic acid having 12 to 18 carbon atoms will be discussed in this study. This condensation is done at moderate reaction temperature (<$25^{\circ}C$) in aqueous alkaline solution. The products of this reaction were identified by UV/VIS spectroscopy and infrared spectroscopy. For these compounds, surface active properties and physical properties including isoelectric point, Krafft point, surface tension, critical micelle concentration(cmc), foaming power, viscosity behaviour, water holding capacity, skin irritation and emulsifying power were measured respectively. The experimental results received that the products have a good emulsifying power, excellent water holding capacity while having low skin irritation. Thus, these derivatives will be expected to be used as an emulsifying agent for O/W type cosmetic emulsion.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2088-2095
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• 2023

The safety of nuclear installations is largely determined by the tightness of fuel elements cladding. As the Fukushima nuclear accident showed, the main task in case of loss of power supply is to ensure reliable removal of residual heat release from spent fuel pool (SFP) with irradiated fuel assemblies (IFAs). The paper presents the results of calculated-experimental studies and thermal-hydraulic modeling of temperature storage modes of IFAs in SFP. Experimental studies of SFP's temperature regime and calculated evaluation of residual heat removal due to the thermal conductivity of building structures surrounding the SFP were performed. To ensure the safe operation of research reactors, it's necessary to know the IFA's residual heat power (RHP) in the reactor and SFP, which is determined depending on the operating time of fuel assemblies (FAs) and the IFAs calculated holding time. The FAs operating time depends on the reactor energy output. The IFAs calculated holding time is determined by the fuel burnup, U-235 mass in the fuel, and reactor utilization factor. The IFAs fuel burnup was calculated using the MCU-PTR program. Also presented are the RHP's calculation results using some of the empirical dependencies. The concept of a passive heat removal system (PHRS) based on thermosyphon's operating principle was proposed.

• Journal of The Korean Association For Science Education
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• v.32 no.1
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• pp.46-63
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• 2012

The purpose of this research is to explore factors which influence visitors' attention on exhibition panels by analyzing visitors' attention according to topic types and visitor group types. The subjects of this research are exhibition panels of a Tesla Coil exhibition in the Gwacheon National Science Museum. The exhibition panels' topic are basic concepts, explanations of phenomena, operating principles, applications and historical background. These topics are selected through a survey of visitors' intellectual needs for a Tesla Coil. Five new exhibition panels according to the topics are developed and visitor groups' behaviors in front of the panels are recoded in natural situations. The total participant groups are 586 groups, which includes individual student (30.0%), individual adult (20.6%), student group (28.2%), adult group(2.4%), and family group (18.8%). Visitors' attention to exhibition panels is sub-categorized into attracting power and holding power. Attracting power is defined by the percentile of group numbers who attend to an exhibition panel more than 3 seconds to the total group numbers who attend to an exhibition panel for more than a glance. Holding power is defined by average attention time and decay time. The attracting powers of historical background and application panels are 72.3% and 68.8% respectively, while that of the basic concept panel is 47%. Average attention times of explanation of phenomena and operating principle are 37.0 and 34.2 seconds, while those of historical background and application panels are 25.4 seconds. The decay times of each panel shows the same patterns of average attention times. Attracting powers of panels easy to approach and holding powers of panels with in-depth scientific concepts seems to be high. Attracting powers of the individual adult, family, and student group are 66.9%, 66.4% and 62.4% respectively, while the attracting power of the adult group and individual student are 57.1%, and 55.7%. Average attention times of the student group, family, adult groups are 34.0, 33.0, 31.6 seconds respectively, while that of individual student is 19.5 seconds. The decay times of each group shows the same patterns of average attention times. Both of attracting powers and average attention times of the student group and family group are high, while both of individual student are low. Tentatively, attracting powers of exhibition panels seems to be influenced more by topic types of panels, and holding power seems to be influenced more by group type. But these results are very limited and further studies are needed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.174-177
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• 2004

The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand the microstructure variation evolution. The microstructure change evolution occurs by recovery, recrystallization and grain growth phenomena. The dynamic recrystallization evolution has been studied in the temperature range $950-1250^{\circ}C$ and strain rate range $0.05-5s^{-1}$ using hot compression tests. The metadynamic recrystallization and grain growth evolution has been studied in the temperature range $950-1250^{\circ}C$ and strain rate range 0.05, $5s^{-1}$, holding time range 5, 10, 100, 600 sec using hot compression tests. Modeling equations are developed to represent the flow curve, recrystallized grain size, recrystallized fraction and grain growth phenomena by various tests. Parameters of modeling equation are expressed as a function of the Zener-Hollomon parameter. The modeling equation for grain growth is expressed as a function of initial grain size and holding time.