• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.88-95
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• 2001

Stator core loss has significant adverse effects when an induction motor is controlled by the conventional vector control method. Therefore, taking core toss into account should make it possible to control the torque very precisely. This paper proposes a speed sensorless vector control method for an induction motor at optimum efficiency and high response taking core loss account. The proposed vector control system consists of a speed adaptive rotor flux observer which takes core loss into account and employs a direct vector control which compensates for the influence of core loss. Also, in this paper, a vector controlled induction motor with a deadbeat rotor flux controller is developed. The method ensures optimum efficiency in the steady state without degradation of the dynamic response. The validity of the proposed technique is confirmed by simulation results for induction motor drive system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.12
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• pp.1218-1229
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• 1991

The time optimal position control design can be repeatedly taken from the initial state of a dynamic system to a desired one as fast as possible in the industrial drives. In this case, an induction machine parameters will vary due to temperature, frequency, and saturation effects. In particular, the rotor resistance changes critically with temperature and frequency. These changes affect the command values of the stator current components and slip speed. There is a mismatch between the commanded variables and actual ones of the induction motor drive, and this situation leads to coupling of the vector controller from the plant, i.e. the induction motor . Consequences of such a coupling include the initiation of oscillations of the rotor flux and unsuitable switching of electromagnetic torque for the induction motor servo drive. Therefore, this paper describes a rotor resistance parameter compensating method for the induction motor, And the validity of the proposed design method is confirmed by simulation studies and experiment results.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.1-8
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• 2005

The industrial induction motor is widely used in the rotating electrical machine for the transmission of power. It is very reliable equipment, but it could lead to the loss of production and lift when failure occurs. Therefore, the failure data is acquired and analyzed by attaching an exclusive instrument to existing induction motor. However, these instruments could lead to side effects, increasing the production costs, because they are very expensive. The purpose of this study is the development of an induction motor bearing failure diagnosis system constructed using LabVIEW which can be supplied the kernelled function, process monitoring and current signature analysis. In addition, the availability and reasonability of the constructed system was examined for an induction motor with failure defects in outer raceway and ball bearing. From the results, it shows that failure diagnosis system constructed is useful for real-time monitoring with detection of bearing defects over the web.

• The Journal of Korean Medicine
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• v.22 no.1
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• pp.22-32
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• 2001

This study was conducted to investigate the antitoxic effects of Houttuynia cordata THUNB with chloroform and ethyl acetate fractions. The results were as follows: 1. Detoxication effects of chloroform and ethyl acetate fractions of Houttuynia cordata THUNB were increased in proportion to the dosages. Detoxication effects of ethyl acetate fraction of Houttuynia cordata THUNB were higher than chloroform fraction of Houttuynia cordata THUNB's results and detoxication effects in the kidneys were higher than results for the liver. 2. Metallothionein concentrations in the liver were higher than concentrations in the kidneys, and ethyl acetate fraction of Houttuynia cordata THUNB was higher than chloroform fraction of Houttuynia cordata THUNB in induction of metallothionein. 3. After the administration of chloroform and ethyl acetate fractions of Houttuynia cordata THUNB, body weights increased in proportion to chloroform and ethyl acetate fraction s dosage of Houttuynia cordata THUNB but changes of body weight dminished after 3 weeks. From the above results, this study suggests that chloroform and ethyl acetate fraction of Houttuynia cordata THUNB increased metallothionein induction to cadmium intoxication in rat s kidney and liver and decreased the toxicity of cadmium in rats.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.352-362
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• 1999

Thiopental sodium is known as ultrashort-acting barbiturates and can be employed advantageously for numerous conditions. But thiopental has the side effects of cardiovascular and respiratory systems which has barbiturates and are depend on the dose of thiopental. The side effects are reduced when the thiopental is preceded by a tranquilizer and sedative. In these drugs, benzodiazepines have the minimal effects of cardiovascular and respiratory systems. In this study, the effects of midazolam preanesthetic administration, followed by thiopental anesthetic induction, on cardiovascular system and thiopental induction requirement were studied in 14 mixed breed dogs. Cardiovascular data were recorded baseline, after premedication of saline 0.45 ml/kg or midazolam 0.1, 0.2, 0.4, 0.8 mg/kg, intubation, and 5, 10, 15, 20, 30 minutes after intubation. Extubation, head-up, sternal recombency, standing, and walking recovery times were recorded. The results were summarized as follows; (1) The 0.1, 0.2, 0.4, and 0.8 mg/kg dosages of midazolam insignificantly decreased thiopental dose requirement necessary to accomplish intubation by 6, 20, 21 and 28%. (2) The 0.1, 0.2, 0.4, and 0.8 mg/kg dosages of midazolam insignificantly reduced the times of extubation, head-up, sternal recumbency, standing, and walking recovery. (3) Midazolam was effective in reducing the frequency and duration of arrhythmia after intubation. (4) Heart rates of preanestheic midazolam administraion groups increased after thiopental injection which insignificantly changed smaller than those of control group. (5) Arterial blood pressures did not vary significantly among groups.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.136-147
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• 2004

In this study, the characteristics of magnetotelluric (MT) responses due to a three-dimensional (3-D) body are analyzed with 3-D numerical modeling. The first model for the analysis consists of a single isolated conductive body embedded in a resistive homogeneous half-space. The second model has an additional conductive overburden while the other conditions remain the same as the first one. The analysis of apparent resistivities shows well that the 3-D effects are dominant over some frequency range for the first model. Two mechanisms, current channeling and induction, for secondary electric fields due to the conductive body are analyzed at various frequencies: at high frequencies induction is more dominant than channeling, while at low frequencies channeling is more dominant than induction. Tippers have a strong relation to the position of anomalous body and the real and imaginary parts of induction vector also indicate the position of anomalous body. off-line conductive anomaly sometimes causes severe problem in 2-D interpretation. In such case, induction vector analysis can give information on the existence and location of the anomalous body. Each parameter of the second model shows similar responses as those of the first model. The only difference is that the magnitude of all parameters is decreased and that the domain showing the 3-D effects becomes narrower. As shown in this study, the analysis of 3-D effects provides a useful and effective means to understand the 3-D subsurface structure and to interpret MT survey data.

• 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.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3571-3580
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• 2023

The application of the induction bending process to pipe systems in various industrial fields is increasing. Recently, efforts have also been made to apply this bending process to nuclear power plants because it can innovatively reduce welded parts of the curved pipes, such as elbows. However, there have been no cases of the application of induction bending to the piping of nuclear power plants. In this study, the applicability of the P91 induction bending piping for the sodium-cooled fast reactor PGSFR was validated through high temperature low cycle fatigue tests and creep tests using P91 induction bending pipe specimens. The tests confirmed that the materials sufficiently satisfied the fatigue life and the creep rupture life requirements for P91 steel at 550 ℃ in the ASME B&PV Code, Sec. III, Div. 5. The results show that the effects of heating and bending by the induction bending process on the material properties were not significant and the induction bending process could be applicable to piping system of PGSFR well.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.809-815
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• 2014

The induction heating bending process, which has been recently applied to nuclear piping, can generate residual stresses due to thermomechanical mechanism during the process. This residual stress is one of the crack driving forces that have important effects on crack initiation and propagation. However, previous studies have focused only on geometric shape variations such as the change in thickness and ovality. Moreover, very few studies are available on the effects of process variables on residual stresses. This study investigated the effects of process variables on the residual stress distributions of induction heating bended austenitic stainless steel (316 series) piping using parametric finite element analysis. The results indicated that the heat generation rate and feed velocity have significant effects on the residual stresses whereas the moment and bending angle have insignificant effects.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.333-336
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• 1988

This paper is presented the two dimensional flux distribution analysis of a double sided linear induction moter with the end effects and the transeverse edge effects, which is caused by the finite length and width of the stator iron. The results are expected to be used to increased the understanding of DLIM characteristics and design