• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.324-326
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• 1999

For induction motors cannot maintain constant speed in various speed conditions, synchronous motors are generally used. But synchronous motor oscillate in shocking load, and it cannot start by itself for the lack of starting torque. In this paper, we analyzed the synchronous induction motor which has both characteristics, and compared the experimental results with FEM analysis.

• 전기의세계
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• v.30 no.12
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• pp.832-837
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• 1981

The study of PLL System to control the Speed of three phase induction motor is described. By solving some problems of conventional PLL system, the system has ability to be easily locked under any conditions. In order to study response velocity and stability of system, this paper presents different filter types and methods of determination of time constant.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.129-134
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• 2001

Winter bud explants from 15 individual angelica tree (Aralia elata) were cultured in vitro to find out optimal conditions for somatic embryo induction as well as plant regeneration. Calli are induced and grown on MS medium supplemented with 1.0 mg/L 2,4-D for 4 weeks and subcultured on a half-strength MS medium without phytohormones to induce somatic embryos. Inter-simple sequence repeat (I-SSR) markers were analyzed with total DNAs extracted from the trees. Genotype effects on somatic embryo induction were examined by cluster analysis. Callus induction rate varied from 58.5 to 100% among the genotypes. Somatic embryo induction rate also greatly varied from 0 to 100% among the genotypes. There was a significant difference in somatic embryo induction rate even among the individual trees that showed close genetic relationships each other. This suggested that somatic embryo induction rate in Aralia elata be influenced by a few major specific genes rather than whole genomic similarity among individual trees. Four individuals of Ulneong-7, Cheju-1, Shingu and China, which are recalcitrant to somatic embryo induction, turned out to have a close genetic relationship, suggesting that both physiological and genetic factors affect somatic embryo induction. The results suggest that genotype selection be the most important factor to achieve an efficient propagation, although cultural optimization through medium and explant manipulation may also play crucial roles in somatic embryogensis as well as plant regeneration of these species.

• Journal of Adhesion and Interface
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• v.19 no.4
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• pp.167-172
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• 2018

In this study, a polyurethane hot melt adhesive was synthesized and metal particles sensitive to induction heating were added to produce an induction heating melt adhesive. The thermal behavior and adhesion characteristics of metal particles were investigated according to the kind, size and induction heating conditions. Among the various metal particles, induction heating efficiency was the best when nickel and iron were applied. Induction heating efficiency increased with decreasing metal particle size. In addition, the strength of the induction heating power of the adhesive was high and the adhesive strength was improved as the adhesive thickness was thinner.

• Journal of Plant Biotechnology
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• v.6 no.1
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• pp.39-43
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• 2004

A successful, efficient system for multiple shoot induction and plant regeneration of soybean (Glycine max) was established. Four soybean genotypes were compared for organogenic responses on various media cultured under light conditions. The adventitious shoots (98%, 2.6 shoots/cotyledon) directly from one-day-old cotyledon after germination induced by the hormone treatment and its efficiency was higher than any other conditions. The optimal medium for the induction of multiple shoots from cotyledon in Pungsannamulkong(shoot formation rate, 98%), Lx 16 (83%) and IIpumgeomjeongkong(63%) was MS medium supplemented with 2 mg/L BAP, but for Alchankong(75%), MS medium supplemented with 1mg/L zeatin and 1mg/L IAA, 3% sucrose, 4% Phytagel. Higher root induction (88%) was observed from the shoots placed on rooting medium (hormone-free MS basal). Plantlets were transferred onto the same medium supplemented with 1% activated charcoal for further development. With this treatment, regenerated plantlets were obtained within 7-8 weeks (shoot induction for 4 weeks, rooting and shoot elongation for 3-4 weeks).

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.105-112
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• 2010

Weldlines are generated during the injection molding process when two or more melt flows are brought into contact. The weldlines are unavoidable in the cases of presence of holes or inserts, multi-gated delivery systems, significant thickness change, etc. At the welded contact region, a 'V'-shaped notch is formed on the surface of the molded part. This 'V'-notch deteriorates not only surface appearance but also mechanical strength of the molded part. To eliminate or reduce weldlines so as to improve the weldline strength, the mold temperature at the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. The present study implements high-frequency induction heating in order to rapidly raise mold surface temperature without a significant increase in cycle time. This induction heating enables to local mold heating so as to eliminate or reduce weldlines in an injection-molded plastic part. The effect of induction heating conditions on the weldline strength and surface appearance of an injection-molded part is investigated.

• Journal of Microbiology
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• v.37 no.3
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• pp.141-147
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• 1999

Thirteen transcriptionally-fused carbon starvation mutants, derived from Pseudomonas putida ATCC 12633, were analyzed for their survivability and transcriptional induction profiles upon carbon starvation. One of these mutants, MK114, which exhibited the lowest survivability and the highest induction rate, was selected and further examined under different starvation (nitrogen and phosphate) and stress (osmolarity, H2O2, salts, alcohol, and heat) conditions. Under all tested conditions MK114 induced ${\beta}$-galactosidase activity, implying that the interrupted gene (cst114) is a general starvation and stress response gene. The rate of induction ranged from 2.6-fold for phosphate starvation to 3.7-fold for osmotic shock. The mini-Tn5 flanking DNA was cloned from the chromosome of MK114. The cloned DNA fragment exhibited carbon starvation activity, indicating that this fragment contains a carbon starvation-related promoter region. This region was partially sequenced. Possible physiological roles of Cst114 in a carbon sensing mechanism and in other stress responses are also discussed.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.173-175
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• 2004

This paper presents a novel design of a self tuning PI controller of induction motor using fuzzy control. In this approach, the fuzzy tuning of a PI controller gains is achieved through fuzzy rules deduced from many robustness simulation tests applied to several induction motors, for a variety of operating conditions such as response to speed command from standstill, step load torque application and speed variations, with nominal parameters and an changed rotor resistance, self inductance and inertia. Simulation results on a speed controller of induction motor are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.27-34
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• 2007

The rotor faults of induction motors may cause bad effects on the performance of the induction motor. This paper proposes the detecting technique of these faults by analyzing the waveform of the induced current and voltage of search coil using numerical analysis and the experiment. Several defective rotor bars are simulated to analyze the fault conditions-broken bars and high resistance of rotor bars. In order to prove the usefulness of the proposed method, we made an prototype experimental apparatus. The waveform of the induced voltages in search coil has the obvious characteristics and it is easy to differentiate the normal rotor from the abnormal one. The experimental results show that the proposed method is useful to detect the rotor fault conditions.

• Journal of Welding and Joining
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• v.33 no.1
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• pp.80-86
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• 2015

The purpose of this study is to establish the predictive method of the angular distortion caused by the line heating process with high frequency induction heating. In order to do it, the heat input model for the high frequency induction heating system was established through comparing the temperature evaluation results obtained by both FEA and experiment. The critical heating conditions to prevent the degradation of the work piece with various thicknesses were identified by FEA and microstructure test results. Under the critical heating conditions, the extensive line heating tests were performed. According to the test results, it was found that the angular distortion behavior of the heated plates could be defined as the function of heat intensity and the rigidity of heated plate. In addition, it was clarified that the angular distortion strongly depended on the size of test specimen such as the length and the width of the heated plate. Based on these results, the predictive equation for the angular distortion was established with the function of heat intensity, bending rigidity and size of heated plate.