• Journal of the Korean Magnetics Society
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• v.23 no.3
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• pp.89-93
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• 2013

In this study, magnetic concentrators which could be used to enhance sensitivity of Hall effect sensor were analyzed by using FEM. The parameters for FEM analysis were the thickness and edge shape of magnetic concentrator and relative position of magnetic concentrator against Hall element. Magnetic field in z direction decreased with increasing of the thickness of magnetic concentrator, of which tendency was similar to apparent relative permeability calculated with demagnetizing factor of magnetic concentrator. There were optimal thickness and edge shape of magnetic concentrator according to the relative position of magnetic concentrator against Hall element.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.2
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• pp.50-57
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• 1998

In this paper, we propoe a log N-stage ATM concentator. ATM concentrator is used in the ATM access network to concentrate the traffic offered at UNI, so that high utilization of the newtork rewources is achieved. The concetrator may be used as a construction block in the design of ATM switch. We define abasic element, named equalizer, and decribe its function and theory to construct an efficient concentrator using the element. In addition, a control scheme to enhance the concentrator to a superconcentrator is presented, which enables the concentration to start from an arbitrary output. This scheme makes it possible to construct an efficient ditributior or a barrel shifter which are often used in ATM switch and other application. The proposed concentrator has a low hardware complexity of O(N log N), thus it is economical to implement. Also, the time complexity of proposed concentrator for determining the rouging is O(N log N), which is faster than that of the existing ones.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.1
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• pp.1-7
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• 1974

This paper discribes the reflector type ultrasonic concentrator which makes hghintencity of ultrasonic field. This was made by rotating parabolic surface which only using total reflection aria, that makes boundary by the critical angle of reflection of sound. I made two binds of concentrator acording to the type of ultrasonic transduser: one is internal surface reflector type concentrator, which is available for disc type transducer, and the other is external surface reflector type concentrator which is available cylinderical transduser. In the mony aspects the reflector tripe concentrator is supel'ier to the reflection type concentrator as plastics lens; It is more durable in high temperature and high intencity ultrasonicfield then refrector type concentrator because of it is made by glass or metal, and it has higher. efficiency because of it wasts made by only total reflection aria that is without absoption lose. I think this is useful ultrasonic concentrator in mony industrial field, in which high intencitr of ultrasonic energy was used.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.408-408
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• 2000

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the images.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.11-18
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• 2004

A solar concentrator, named KIERDISH II, was built at KIER in order to investigate the feasibility of high temperature solar energy application system. The constructed concentrator is a dish type solar concentrator with a focal length of 4.68m and a diameter of 7.9m. To successfully operate KIERDISH II, optimal design of the absorber is very important and flux density distribution has to be known. The focal flux density distribution on the receiver was measured. We have observed the shape and size of flux images and evaluated percent power within radius. Flux density distribution is usually measured by a CCD(charge coupled device) camera and a radiometer. In this paper we present a flux mapping method to estimate the characteristic features of the flux density distribution in the focal region of solar concentrator. The minimum radius of receiver is found to be 0.15m and approximately 90% of the incident radiation is intercepted by receiver aperture.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.1
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• pp.49-56
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• 2014

In this study, the generation efficiency of the limited area of a concentrator solar cell was increased by using a solar concentrator and a tracking device. Heat generated by the solar cell was collected using a thermal absorber for supplying hot water or heating. Thus, the concentrator solar cell system provided electricity and heat simultaneously. Tracking of the sun by detecting the sun's position, repositioning of heating device towards the east after sunset, and shutting down of system after sunset were successfully implemented using an illuminance sensor (CdS) and Simulink, a commercial software package. We performed parametric analysis of the velocity, fin installation, and entrance location with respect to the operating temperature of the concentrator solar cell. A heat transfer simulation model was developed for comparing the actual temperature profiles of the concentrator solar cell and thermal absorber, and good agreement was found between the results of the simulations and the experiments.

• Mineral and Industry
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• v.26
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• pp.13-21
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• 2013

This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1mm in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about $3%WO_3$ grade and 90% recovery, respectively, from the feed containing about $0.8-1.0%WO_3$ grade.

• Journal of Environmental Science International
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• v.18 no.3
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• pp.283-288
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• 2009

This is a study on the volatile organic compounds(VOCs) concentrator with zeolite adsorptive honey rotor and catalytic combustion system for abating VOCs emitted from printing industry. VOCs emitted from the printing industry is mainly caused by organic solvent of printing ink. The content of organic solvents in printing ink varies from 40% to 75% and its content in the gravure ink is higher than that in any other ink. The average concentrations of each VOCs are 139 ppm for toluene, 152.1 ppm for MEK, 256.9 ppm for methanol and 42.9 ppm for isopropyl alcohol. We used zeolite honeycomb for absorbent of VOCs concentrator and palladium for catalyst combustion system. This system abated over 96% of emitted total VOCs, 98% of toluene, 100% of MEK, 92% of methanol and, 100% of isopropyl alcohol. It is concluded that the low-leveled high-volume VOCs emitted from printing process were removed almost by concentrator with zeolite adsorptive honey rotor and catalytic combustion system.

• Journal of the Korean Solar Energy Society
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• v.21 no.4
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• pp.55-62
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• 2001

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using a computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the captured images.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1350-1354
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• 2007

As the importance of low power design is emphasized, power consumption became one of the standards that represent the performance of the system. The purpose of this study is to decide design variable that minimize power consumption for the oxygen concentrator in two bed-one compressor 8 step PSA process that has above 90% purity at 3lpm by using given constants and selected parameters. Setting selected parameters as cycle time and equalization time, optimization for PSA process in the oxygen concentrator is progressed. For this, we need to know the features and basic principals of PSA process and to deduce objective function of performance analysis. Validations for objective function and lots of experiments are needed too. By using the characteristic curve of the compressor and the pressure curve of the process for 1 cycle, objective function was set. After theoretical 2 dimensional optimized paths was obtained. And then, by experiment, theoretical optimized path was verified.