• Journal of Welding and Joining
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• v.22 no.4
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• pp.65-72
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• 2004

The aim of this study is to investigate the optimum drawing parameter for BAS111 welded tubes. The BAS111 aluminium alloy tubes with 25.4mm in external diameter and 1.5mm in thickness for heat-exchangers were manufactured by high frequency induction welding with the V shaped convergence angle 6.8$^{\circ}$ and power input 50㎾. With increasing the reduction of area (1.6, 5.8, 11.5, 14.2, 18.5, 22.5%) by drawing, tensile strength was increased and elongation was decreased. With increasing the reduction of area by drawing, hardness in weld metal increased rapidly, while that of base metal increased slowly. In the specimen with the outer diameter smaller than 22mm, hardness of weld metal was higher than that of base metal. The optimum drawing parameter of area reduction was estimated about 15% because of the work hardening of welds.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.1
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• pp.23-31
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• 1992

It is investigated that Fe-C-N compound layer, defusion layer, and induction hardened layer produced by nitrocarburizing blend heat treatment in austenitic temperature with high frequency induction heating of mild steel specimen sprayed sursulf salt-bath. As the temperature of blend-heat treatment got increased, the thickness and hardness of compound layer and diffusion layer were increased. Compound layer(max. $35{\mu}m$), diffusion layer (max. 2.5mm) and induction hardened layer were gained in the shortest time 10 sec and in the case of $1000^{\circ}C$ total hardness depth of those was about 3.5mm. When the blend-heat treated specimen was reheated, maximum hardness of compound layer was dropped more than that of the reheated compound layer after sursulf treated, whereas hardness of diffusion layer was increased.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.554-560
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• 2011

Single-frequency induction heating equipment caused by a hardening heat treatment process of the double investment in the issue and allow the heat treatment process in order to shorten the time from one process to work simultaneously on two kinds of processes that allow Simultaneous Dual Frequency(SDF) drive scheme technology are described. In this paper, we propose a dual way to drive a simultaneous dual-frequency drive scheme has been implemented. Through simulations and experiments, we can obtain the validity of the proposed inverter for dual-frequency control and power control.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.287-289
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• 2000

Induction heating is utilized in a large and ever-increasing number of application. The most prominent of these are billet heating heat treating, metals joining, and metal melting. In these day, heating roll, a kind of induction heating, is widely used in curing of coatings and fiber industry. In this paper, at first, treated that heating roll's characteristics equation. The second, analysis of magnetic flux and eddy currents distribution using FEM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.429-436
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• 2013

This study considers how the fatigue behavior and probabilistic properties of SAE1055 steel are related to its hardness level. SAE1055 steel was heat-treated using induction hardening. Five types of specimens were prepared (A: base material, B: through hardened material with HV390, C: through hardened material with HV510, D: through hardened material with HV700, and E: surface hardened material with HV700). Fatigue tests were performed under a stress ratio of R = -1 using a 4-point rotary bending fatigue tester. The fatigue behaviors were greatly influenced by the hardness, but the fatigue limit did not increase over a hardness of HV510. In addition, the effect of the hardness level on the failure mechanism was evaluated using a scanning electron microscope. The probabilistic properties of the fatigue life were investigated using a probabilistic S-N approach, and the effect of the hardness level on these properties was evaluated using a residue analysis.

• Journal of Plant Biotechnology
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• v.46 no.1
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• pp.17-21
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• 2019

Ginger is an important monocotyledonous plant belonging to the family Zingiberaceae. The objective of this study was to investigate the regeneration potential of ginger using leaf base explants. Auxins such as 2, 4-D and NAA in combination with BA were used for initiation of callus. Different combinations of both ammonium ($NH^{4+}$) and nitrate ($NO^{3-}$) were also studied for efficient callus production. High frequency of white friable calli was observed on modified Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 2, 4-D, 0.5 mg/L NAA and 0.5 mg/L BA. The highest shoot induction (92.33%), shootlets number ($7.33{\pm}0.33$) and length ($88.33{\pm}4.40$) mm were achieved on MS media containing 0.5 mg/L BA. Regenerated shoots were transferred to in vitro rooting media containing 1.0 mg/L IBA. Afterwards, plantlets with well-developed root and shoot system were subjected to a twostep hardening process. 71% of plantlets survived after secondary hardening without any abnormal morphology.

• Computers and Concrete
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• v.13 no.1
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• pp.97-115
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• 2014

Silica fume is a by-product of induction arc furnaces and has long been used as a mineral admixture to produce high-strength, high-performance concrete. Due to the pozzolanic reaction between calcium hydroxide and silica fume, compared with that of Portland cement, the hydration of concrete containing silica fume is much more complex. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical model is proposed to simulate the hydration of concrete containing silica fume. The heat evolution rate of silica fume concrete is determined from the contribution of cement hydration and the pozzolanic reaction. Furthermore, the temperature distribution and temperature history in hardening blended concrete are evaluated based on the degree of hydration of the cement and the mineral admixtures. The proposed model is verified through experimental data on concrete with different water-to-cement ratios and mineral admixture substitution ratios.

• Fire Science and Engineering
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• v.16 no.2
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• pp.8-13
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• 2002

Induction heating is widely used in today's industry, in operations such as metal hardening, pre-heating for forging operations, melting or cooking. In this paper, the magneto-thermal analysis of an induction heating jar(IH-JAR) was presented as an efficient design. The magnetic field intensity inside the axisymmetric shaped cooker was analyzed using three-dimensional axisymmetric finite element method(FLUX2D) and the effectual heat source was obtained by ohmic losses from eddy currents induced in the jar. The heat was calculated using the heat source and heating equation. Also, it was presented the temperature characteristics of the IH-JAR according to time and relative permeability in stainless parts and in aluminum parts.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.703-705
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• 2002

The actuator consists of winding as a stator and mover includes permanent magnet. The Linear Oscillatory Actuator(LOA) has very few components and a highly simplified structure, and therefore promises to be simple and reliable. In this paper, LOA was designed and manufactured. before design and manufacture, characteristic of thrust was analyzed using FEA. LOA was manufactured according to design specification.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.859-861
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• 2001

The Linear Oscillatory Actuator(LOA) has very few components and a highly simplified structure, and therefore promises to be simple and reliable. The actuator consists of winding as a stator and mover includes permanent magnet. In this paper, LOA was designed and manufactured, before design and manufacture, characteristic of thrust was analyzed using FEA, LOA was manufactured according to design specification.