• Korean Journal of Optics and Photonics
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• v.35 no.2
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• pp.61-70
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• 2024

We demonstrate a laser power meter calibration system based on 12-diode laser sources coupled to single-mode fibres in a wavelength range from 400 to 1,600 nm. In our system, three laser power controllers ensure that the output power uncertainty of all laser sources is less than 0.1% (k=2). In addition, all laser beams are adjusted to have similar beam sizes of approximately 2 mm (1/e²-width) at the measurement position to minimise unmeasured laser power on a detector. As a reference detector, we use an integrating sphere combined with silicon and indium gallium arsenide photodiodes to minimise the non-uniformity and non-linearity of responsivity. The minimum uncertainty of the calibration system is estimated to be 1.1% (k=2) for most laser wavelengths.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.46-51
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• 2008

In this study, evaluation system of the thermal properties of the exothermic agents was investigated. Exothermic agents property evaluation system was developed by metering variation of power supply. Thermal properties of exothermic agents was affected by material mixture condition of exothermic agents, however, it was not affected by temperature. It is possible to make various exothermic agents by means of regulating thermal properties which is based on property evaluation system of exothermic agents.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.4
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• pp.33-40
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• 1987

Arc power is consumed energy per unit time between welding electrodes. The relations between consumed energy and electrode distance, current, voltage are nonlinear characteristics. Therefore commercial A.C. wattmeter cannot be used for measurement of the arc power. Most of arc energy measuring systems are developed for relay contact arc measurement. Relaly arc requires integrated instantaneous power because relay arc finishes in a short instant. But most of welding powers are continually consumed powers, therefore instantaneous power must be continually indicated in the form of averagy value. The author propose a new measurement method of power in which the current and voltage of welding electrode is multiplied and the resultant signal is passed to low pass filter in order to remove higher order frequency components. After integrating, the signal is devided by the integral interval and the results are stored in a computer memory.

• Transactions of Materials Processing
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• v.17 no.5
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• pp.356-363
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• 2008

An evaluation system of the thermal properties of exothermic & insulating materials was developed. By measuring the power supply of the induction furnace, the thermal property of exothermic & insulating materials could be evaluated with high reproducibility at elevated temperature of molten steel. The thermal properties of exothermic & insulating materials were affected by mixing condition of raw materials. The effect of main components of exothermic & insulating materials such as metallic aluminum and $Fe_2O_3$ powder on the exothermic and insulating properties was examined. It could be expected to design and develop various exothermic & insulating materials by means of the evaluation system of the thermal properties.