• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.80-91
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• 1998

In this paper, the estimation of dynamic interlaminar fracture toughness on fracture mode II in CFRP(carbon fiber reinforced plastics) laminates in made. Dynamic ENF(End Notched Flexure) apparatus used in this paper is manufactured by suing Split Hopkinson Pressure Bar. The static and impact load history in the CFRP specimen is measured by using manufactured dynamic ENF tester and 3-point bending test is carried out to find the load history. Also dynamic interlaminar fracture toughness can be found by using the J integral obrained from dynamic analysis in consideration of intertia-force effect.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.15-21
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• 2012

This paper deals with an experimental study on the reaction of muscles by functional electrical stimulation(FES) with the design and fabrication of an ankle reaction apparatus. The ankle reaction apparatus consists of a circuit part and a kinematic part, and it monitors reaction time for a particular angle of joint rotation according to FES. The experimental results showed that the change of the ankle rotation angle was linearly proportional to the change of the magnitude of FES. It also showed that the muscle's reaction time was constant no matter how large the magnitude of the stimulus. The results of this paper can be applied to develop an active-type walking-assistance robot.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.503-507
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• 2002

Mask manufacturing is a high COC and COO process in developing of semiconductor devices, because of the mass production tool with high resolution. Direct writing has been thought to be one of the patterning method to cope with development or small-lot production of the device. This study focused on the development of the direct, mastless patterning process using stereolithography tool for the easy and convenient application to micro and miso scale products. Experiments are utilized by three dimensional CAD/CAM as a mask and photo-curable resin as a photo-resist in a conventional stereo-lithography apparatus. Results show that the resolution of the pattern was achieved about 300 micron because of complexity of SLA apparatus settings, inspite of 100 micro of inherent resolution. This paper concludes that photo resist and laser spot diameter should be adjusted to get finer patterns and the proposed method is significantly feasible to mastless and low cost patterning with micro and miso scale.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.54-60
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• 2004

Flammable substances are frequently used chemical industry processes. An accurate knowledge of the ALTs(Autoignition Temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The AITs describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, ignition delay. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for methanol and ethanol. The A.A.P.E.(Average Absolute Percent Error) and the A.A.D.(Average Absolute Deviation) of the experimental and the calculated delay times by the AITs for methanol were 14.59 and 1.76 respectively. Also the A.A.P.E. and the A.A.D. of the experimental and the calculated delay times by the ATIs for ethanol were 8.33 and 0.88.

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.499-504
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• 1995

Recently, there are deep and much concerns about the objective assessment of diagnosis in Oriental Medicine. Among them, pulse diagnostics is used for the quantitative device of diagnosis. The objective research of pulse diagnosis were mainly conducted by pulse wave. So it is important to gain multi-information for the quantification of pulse diagnosis. We report the development of pulse diagnostic apparatus enable to gain the multi-information, detect the pressure pulse wave in conku(寸口) area and obtain the gradient curve and original pulse wave simultaneously, and consider the pulse wave with the traditional pulse diagnosis at the same time.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.146-151
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• 2010

A comprehensive real-time spectral phase interferometry for direct electric field reconstruction (SPIDER) apparatus for characterizing femtosecond laser pulses is demonstrated. The SPIDER provides the temporal profiles of femtosecond laser pulses, reconstructed at the speed of 3.5 Hz, with parameters of the spectral phase such as group delay dispersion and third-order dispersion. The apparatus is applied successfully to optimize the spectral dispersion of a kHz femtosecond Ti:Sapphire laser by adjusting a grating compressor in real time.

• Transactions on Electrical and Electronic Materials
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• v.14 no.5
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• pp.268-272
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• 2013

The aim of this study was to develop an ultrasonic tooth-whitening apparatus using piezoelectric transducers, which enhance bleaching efficiency by applying ultrasound, while performing a teeth whitening procedure. For this purpose, an ultrasonic transducer was designed and manufactured, and the effects of reduction in the whitening material's concentration and in the whitening treatment time through using the ultrasound cavitation phenomenon were confirmed. Also, the validity of this study was investigated by comparing the whitening performance with a commercialized optical whitener, through color comparison. The results revealed that the ultrasound whitener produced color values that were enhanced by as much as double that of the conventional LED light whitening method. Even when the operational time was reduced by half, the ultrasound method showed superior performance by over 54% compared to the conventional light whitener, revealing that the ultrasound method showed a remarkable treatment reduction effect.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.60-62
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• 2007

This paper presents apparatus and its method for event record of digital substation based on SCL files, which can save communication messages of a variety of IEC61850 international standard applied substation events such as fault. In particular, the device has ability to analyze all of the events and faults, and performs its functions based on SCL files.

• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.41-52
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• 1994

This paper deal with the design of noncontact In-process measurement system which measures the surface roughness during cylindrical grinding. The measuring system is extremely simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. The experimental performance of the apparatus is satisfactory and good results are expected in the actual use. During operation, the surface of a workpiece Is continuously scanned by a laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along both circumferential and feed directions and the surface roughness value is obtained from the reading along the feed direction.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.48-53
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• 1999

It is widely recognized that Hartmann tube for measuring the minimum ignition energy(MIE) of powder. But It requires long time and operational skills for measuring. As a variety of new fine powders are being produced day by day in industry, Japen has been developing a measurement system which employs a new method to create a dust/air mixture in a miniature combustion box. In this system, by vibration, the powder is successively fed downward through a hopper made up of metal mesh, and then it is formed into a thin, certain-like, dust/air mixture. With this new apparatus, three types of powder-Lycopodium, Anthraquinone, and Polyacry-lonitrile-were tested and the data of MIE were compared with those of a conventional apparatus (the Hartmann tube). Two of them agreed satisfactory, but the other, Anthraquinone, showed quite different values. It is guessed that the agglomerations of the powder particles appear because of particle shapes, static-charge and humidity.