• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.6
• /
• pp.745-752
• /
• 2018

ICs(Integrated circuits) for nuclear power plant exposed to radiation environment occur malfunctions and data errors by the TID(Total ionizing dose) effects among radiation-damage phenomenons. In order to protect ICs from the TID effects, this paper proposes a radiation-hardening of the logic circuit(D-latch) which used for the data synchronization and the clock division in the ICs design. The radiation-hardening technology in the logic device(NAND) that constitutes the proposed RH(Radiation-hardened) D-latch is structurally more advantageous than the conventional technologies in that it keeps the device characteristics of the commercial process. Because of this, the unit cell based design of the RH logic device is possible, which makes it easier to design RH ICs, including digital logic circuits, and reduce the time and cost required in RH circuit design. In this paper, we design and modeling the structure of RH D-latch based on commercial $0.35{\mu}m$ CMOS process using Silvaco's TCAD 3D tool. As a result of verifying the radiation characteristics by applying the radiation-damage M&S (Modeling&Simulation) technique, we have confirmed the radiation-damage of the standard D-latch and the RH performance of the proposed D-latch by the TID effects.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.11
• /
• pp.41-52
• /
• 2012

Suction drain method can directly apply vacuum pressure to the soft ground through vertical drains so it can make hardening zones around them. These hardening zones make steeply lower the discharge efficiency of the pore water with decreasing permeability. This paper considered a stepped vacuum pressure to minimize a hardening zone which is one of the important parameters that can decrease discharge efficiency. A series of laboratory tests were conducted in order to examine the effect of the hardening zones and to evaluate their effects to the ground improvements with varying durations which applied stepped vacuum pressures(-20kPa, -40kPa, -60kPa and -80kPa) with Busan marine clay. According to strength(CPT), water content test and theoretical investigation indicate a size of the hardening zone within 7cm and the decreasing ratio of permeability about 2.0~4.0. Also, the total settlements are larger for the stepped vacuum pressure than the instant vacuum loading. The application time with vacuum pressure is determined considering the geotechnical properties of the interested clays. Results of numerical analysis show that consolidation behavior is appropriate to measurement for considering hardening zones.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.148-151
• /
• 2003

In order to achieve reliable but cost-effective crash simulations of stamped parts, sheet forming process effects were incorporated in simulations using the ideal forming theory mixed with the 3D hybrid membrane/shell method, while the subsequent crash simulations were carried out using a dynamic explicit finite element code. Example solutions performed for forming and crash simulations of I- and S-shaped rails verified that the proposed approach is cost-effective without sacrificing accuracy. The method required a significantly small amount of additional computation time, less than 3% for the specific examples, to incorporate sheet forming effects to crash simulations. As for the constitutive equation, the combined isotropic-kinematic hardening law and the non-quadratic anisotropic yield stress potential as well as its conjugate strain-rate potential were used to describe the anisotropy of AA6114-T4 aluminum alloy sheets.

• The Journal of Fisheries Business Administration
• /
• v.29 no.2
• /
• pp.143-161
• /
• 1998

The objective of this study is to analyze the effects of increase in the oyster hatchery on fishermen's income. The results of the analysis are as follows : \circled1 The necessary quantities of oyster seed are 18,000 thousand hanging line. The 29.4%, of that has been applied by ana-seed collection and 29.1% of that has been applied by proseed collection. The demage of oyster aquaculture business is estimated about 35 billion won or 83 billion won. \circled2 The production cost per hanging line of the oyster hatchery is 1,974 won. And if it is sold by 2,500 won, return on investment will be 31.9%. Therefore profitability of the oyster hatchery is very good. \circled3 There are four important determinant variables of profitability to the oyster hatchery. In the order of their effects, it is operation number, seed price, production cost, and quantity of production. \circled4 If differences of price between the artificial hardening oyster seed and the natural hardening oyster seed are more less 1,430 won, the former is better. \circled5 The necessarily quantities of the oyster hatchery are estimated 160 units in the scale of 10,000 hanging line production to one operation. \circled6 The effect of increasing income of fishermen are estimated about 85.3 billion won or 124.5 billion won from increase in the oyster hatchery.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.31-38
• /
• 1991

The current-voltage characteristics at annealed Be-Cu alloy(1.8-2 wt% Be, 0.2 wt% Co+Ni) interfaces have been studied by means of the cyclic voltammetric method. The specimens were annealed in nitrogen gas($N_{2}$) furnace at 36$0^{\circ}C$ for 1.5 hours. After annealing, the vickers hardness(HV) was increased from 210 to 385. The used solutions were distilled water(H$_{2}$O), 10$^{-3}M\;CsNO_{2},10^{-2}M\;KCl,10^{-2}M\;KOH,10^{-4}M\;H_{2}SO_{4}$ aqueous electrolytes, and ethylalcohol ($C_{2}H_{5}OH$), etc. The cyclic voltammograms showed significant current-voltage characteristics between the annealed and unannealed specimens at the same conditions. The age hardening and the related surface potential barrer and dissolution effects have been observed during the whole experimental process. The dissolution process of annealed Be-Cu alloys was effectively retarded by the age hardening phenomenon. The age hardening effect also raised the surface potential barrier of Be-Cu alloys. The interfacial phenomena of Be-Cu alloys seem to be one of good models for understanding the activation process.

• Journal of the Korean Society for Heat Treatment
• /
• v.12 no.4
• /
• pp.327-337
• /
• 1999

A series of Ni-Cr-Mo alloy steels were austenitized, quenched to martensite, and tempered at various temperature and time conditions. Tensile testing was conducted at room temperature with cylindrical specimens, and hardness was measured using Rockwell hardness tester. In the tempering stage I, high strain hardening and yield strength accounted for the high ultimate strength and hardness. In the tempering stage II, strengths and hardness linearly decreased with increasing tempering temperature. Specimens tempered in the temperin stage III showed incipient discontinuous yielding and tensile strengths only slightly higher than yield strengths. Ductilities decreased slightly in specimens tempered in the tempered martensite embrittlement range, and severely decreased in specimens tempered for 10 hours at $500^{\circ}C$ in the temper embrittlement range. Specimens tempered at $600^{\circ}C$ for 10 hours showed recrystallized microstructures, a number of fine dimples, and increased strain hardening, probably due to the precipitation of alloy carbides. The simple formulae for the mechanical properties of these steels were suggested as a function of carbon content and Hollomon-Jaffe tempering parameter.

• Journal of Korea Foundry Society
• /
• v.29 no.2
• /
• pp.70-77
• /
• 2009

The aim of this study was to develop a Mo and V free low alloy cast steel materials, enabling the significant cost- and time-savings in manufacturing and maintaining the insert of cold pressing die without impairment of the important properties. For this purpose, the effects of Si content on combinations of important properties such as hardness, hardenability, and weldability, and strength were systematically investigated. In order to evaluate the applicability as the insert of cold pressing die, the mechanical properties were measured after spheroidization annealing, quenching and tempering, and flame hardening heat treatments, respectively. After the Q/T and F.H. treatments, the developed 0.8${\sim}$1.6%Si containing Mo and V free low alloy cast steels showed excellent matrix strengthening effect, hardenability, and weldability, fulfilling the industrial criterion of the mechanical properties for automobile cold pressing die insert.

• Advances in concrete construction
• /
• v.5 no.2
• /
• pp.155-171
• /
• 2017

The phenomenon of concrete column shortening has been widely acknowledged since it first became apparent in the 1960s. Axial column shortening is due to the combined effect of elastic and inelastic deformations, shrinkage and creep. This study aims to investigate the effects of ambient temperature, relative humidity, cement hardening speed and aggregate type on concrete column shortening. The investigation was conducted using a column shortening prediction model which is underpinned by the Eurocode 2. Critical analysis and evaluation of the results showed that the concrete aggregate types used in the concrete have significant impact on column shortening. Generally, aggregates with higher moduli of elasticity hold the best results in terms of shortening. Cement type used is another significant factor, as using slow hardening cement gives better results compared to rapid hardening cement. This study also showed that environmental factors, namely, ambient temperature and relative humidity have less impact on column shortening.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.340-350
• /
• 2007

The major objective of this study is to investigate the fatigue effects of rail pad on High Speed Railway with concrete slab track system. It analyzed the mechanical behaviors of HSR concrete slab track with applying rail pad stiffness based on fatigue effect(hardening and increasing stiffness) on the 3-dimensional FE analysis and laboratory test for static & dynamic characteristics. As a result, the hardening of rail pad due to fatigue loading condition are negative effect for the static & dynamic response of concrete slab track which is before act on fatigue effect. The analytical and experimental study are carried out to investigate rail pad on fatigue effected increase vertical acceleration and stress and decrease suitable deflection on slab track. And rail pad based on fatigue effect induced dynamic maximum stresses, the increase of damage of slab track is predicted by adopting fatigue effected rail pad. after due consideration The servicing HSR concrete slab track with resilient track system has need of the reasonable determination after due consideration fatigue effect of rail pad stiffness which could be reducing the effect of static and dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.

• Journal of the Korean Society for Heat Treatment
• /
• v.18 no.3
• /
• pp.172-176
• /
• 2005

Modern automobiles are built with a steadily increasing variety of materials and semifinished products. The traditional composition of steel sheet and cast iron is being replaced with other materials such as aluminum and magnesium. But low formability of these materials has prevented the application of the automotive components. The formability can be enhanced by conducting the warm hydroforming using induction heating device which can raise the temperature of the specimen very quickly. The specimen applied to the test is A6061, A7075 extruded tubes which belong to the age-hardenable aluminum alloys. But in the case of A6061 age hardening occurs at room temperature or at elevated temperatures before and after the forming process. In this study the effects of the heating condition such as heating time, preset temperature, holding time during die closing and forming time on the hydroformability are analyzed to evaluate the phenomena such as dynamic strain hardening and ageing hardening at high temperatures after the hydroforming process.