• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.136-141
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• 2015

We studied the compact anode design to develop 100 kW rotating anode X-ray tube with large focal spot 1.2 mm, small focal spot 0.6 mm and tube voltage 150 kV for large hospital digital radiography using computer thermal simulation. The larger thermal radiation effect in a high vacuum can reduce the temperature of anode so the method to increase the surface area of anode is investigated. The anode has the multi-tier shape at the back side of TZM body of anode and also bigger diameter of anode. The number of multi-tiers was varied from 6 to 15 and the diameter of anode was also varied from ${\Phi}74$ to ${\Phi}82$. From ANSYS transient thermal simulation result, we could obtain $1056.4^{\circ}C$ anode maximum temperature when applying 100 kW input power at 0.1 second on target focal track which is less than $1091^{\circ}C$ of the conventional 75 kW X-ray tube with reduced anode weight by 15.5% than the conventional anode. The compact anode of reduced anode weight is able to improve the unwanted noise when the rotor is rotating at high-speed and also reduce the rotational torque which the cost effective stator-coil is possible. It is believed that the anode with 15 ea multi-tiers using ${\Phi}82$ can satisfy with the specification of the anode heat capacity. From the results of this paper, it has been confirmed that the proposed compact anode can be used as the anode of 100 kW rotating anode X-ray tube for digital radiography.

• The korean journal of orthodontics
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• v.45 no.6
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• pp.289-298
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• 2015

Objective: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs). Methods: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth. Results: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle. Conclusions: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.7-13
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• 2000

A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the heat transfer characteristic of the rotating cryogenic system. To examine the insulation performance of the experimental rotor. temperature was measured at each part of the system at various rotaing speeds from 0 rpm to 600 rpm. Total heat leak into the inner vessel was calculated by measuring the boil-off rate of liquid helium. Conduction heat leak to the inner vessel was obtained by the vent tube, and radiation heat leak was calculated by subtracting the conduction heat lent from the total heat leak. There seemed to be no rotaional dependency of total heat leak at least up 600 rpm.

• Steel and Composite Structures
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• v.21 no.4
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• pp.755-773
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• 2016

In the present paper, a new high-order simple-input analytical method is used to study thick laminated composite straight tubes subjected to combined axial force, torque and bending moment. The most general displacement field of elasticity for an arbitrary laminated composite straight tube is obtained to analytically calculate stresses under combined loadings based on a layerwise method. The accuracy of the proposed method is subsequently verified by comparing the numerical results obtained using the proposed method with finite element method (FEM) and experimental data. The results show good corresponded. The proposed method provides advantages in terms of computational time compared to FEM.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.18-20
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• 2002

In this paper, the construction elements of the induction motor was represented by the magnetic tube. The magnetic tube is basis of the magnetic equivalent circuit. The magnetic equivalent circuit method is convenient of complicated analysis of the transient state of the induction motor. Because the method is restriction on only one direction of magnetic flux. Air gap magnetomotive force was calculated by magnetic equivalent circuit method. Starting transient torque and phase current of the induction motor was confirmed by the theoretical calculation and the experiments.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.11-19
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• 2015

Recently, the cross flow turbines attract more attention for their good performance over a large operating regime at off design point. This study employs a very low head cross flow turbine, which has open inlet duct and has barely been studied before, to investigate the performance of the cross flow turbine with air suction from the rear part of the runner. Unlike conventional cross flow turbines, a draft tube is attached to the outlet of runner to improve the turbine performance. Water level and pressure in the draft tube are monitored to investigate the influence of air suction. Torque at local blade passage of three parts of runner is examined in detail under the conditions of different air suction. Consequently, it is found that with proper air suction in the runner chamber, the water level in the draft tube gradually drops to Stage 2 of the runner and the efficiency of the turbine can be raised by 10%. Overall, the effect of air-layer on the performance of the turbine is considerable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.666-671
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• 1993

Fatigue life prediction under multi-axial variable load were performed for Aluminium 7075-T651 alloy using SAE Notched specimen & Torque tube shaft component specimen. When variable multiaxial load is applied to material, maximum damaged plane(critical plane) change. To clarify the situation, experiment is performed on two different changing load path. For multiaxial fatigue life prediction, miner rule is expanded to critical plane theory. Shear based parameter and Elliptical parameter give better correlation. This suggests that miner rule can be applicable on multi-axial variable load.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.63-66
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• 2000

A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the jheat transfer characteristic of the rotating cryogenic system.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.10-19
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• 2014

We designed bearingless rotor hub system which replace mechanical hinge/bearing with composite beam component and conducted fatigue analysis for flexbeam and torque tube. Extension/bending/torsional stiffness was calculated from 2D section analysis using VABS and 2D section structure analysis was applied for strain calculation. S-N curve of each composite material was generated using Wohler equation and fatigue analysis was conducted on weakness section which was decided from static structure analysis. CAMRAD II was used for load analysis and load analysis result was applied HELIX/FELIX standard load spectrum to generate bearingless rotor system load spectrum which was used fatigue safe life analysis.

• Textile Coloration and Finishing
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• v.12 no.3
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• pp.207-217
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• 2000

A new, high-efficiency ultrasonic fabric washing machine was developed to be an energy-efficient washing machine and to enhance fabric washing quality in washing processes of the dyeing and finishing process in the textile industry. This system is composed of ultrasonic wave generator, air blowing nozzle, torque motor for fabric tension control, and enclosed washing bath, multi-tube type exchanger, noiseless heater, air cylinder, expander roller, mangle upper and lower rollers, bend bar, dancer, shower spray nozzle, and solenoid valve, and so on. These elements are synergised for fabric washing. One of the very important principles is the low tension fabric running system. For an efficient washing effect, a counter flow system is also adopted. The new system also adopts the dancer and torque motor to control fabric tension and prevent fabric creasing. Shower spray nozzle, counter flow and overflow apparatus, and air-blowing apparatus are adopted to enhance the fabric washing effect. In this study, peach yoryu, exter, and moss crepe fabrics were washed by the general and ultrasonic washing systems under different conditions respectively. The washing efficiency was affected by the fabric running speed and characteristics of fabrics. Size content after washing increased with increasing the fabric running speed. The values in the general washing system were higher than those of the ultrasonic washing system. The changes of conductivity in the ultrasonic and the cooling bath were affected by the running time under the ultrasonic generating. The values of conductivity decreased as the experimental time passed.