• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.306-313
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• 1973

With the intention of obtaining technical data for the industrial production of ${\gamma}-MnO_2$ for dry cell depolarizer by electrolytic oxidation of acidic manganese sulfate solution made from domestic rhodochrosite, optimum conditions of ore leaching, purification of leached solution and electrolytic oxidation of divalent manganes to tetravalent were investigated using simulated micro pilot plant having a production capacity of 4 kg of $MnSO_4$ per day. The nature and quality of the products were investigated by means of chemical analysis, DTA, X-ray diffraction and electron microscopy. The cell activity of $MnO_2$were examined by cell discharging character measurements. The optimum electrolysis conditions were as follow: Temperature of the electrolyte, above $90^{\circ}C$; current density, 0.7${\sim}A/dm^2$; anode materials, graphite or lead ; concentration of electrolyte, $MnSO_4 50{\sim}150g/l $ g/l and $H_2SO_4/MnSO_4 = 0.15{\sim}0.25$. Under the best condition the current efficiency was 99% and the products were almost pure ${\gamma}-MnO_2$. The cell discharging character were good and almost the same as that of regular grade commercial electrolytic manganese dioxide.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1184-1186
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• 1995

The absorption spectra of synthesis of azobenzene containing long chain fatty acids were investigated by UV spectrophotometer in chloroform solution. Also, the pressure-area isotherms of the molecules on the water-air interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystals by the conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) films on quartz slides have been measured. From these measurements, following conclusions were obtained. Azobenzene containing long chain fatty acids show a photoisomerization by irradiation of UV light and visible light alternatively. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_n$ increased. Also the LB films show a photoisomerization characteristics. So the LB film of azobenzene containing long chain fatty acid has possibility to being applied to functional molecular device such as photomemory and light switching.

• Journal of Powder Materials
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• v.18 no.6
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• pp.510-516
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• 2011

In the present study, potassium and caesium doped Ag/$Al_2O_3$ catalysts were synthesized by simple wet impregnation method and evaluated for selective catalytic reduction (SCR) of NOx using methane. TEM analysis and diffraction patterns demonstrated the finely dispersed Ag particles. BET surface measurements reveal that the prepared materials have moderate to high surface area and the metal amount found from ICP analysis was well matching with the theoretical loadings. The synthesized K-Ag/$Al_2O_3$ and Cs-Ag/$Al_2O_3$ catalysts exhibited a promotional effect on deNOx activity in the presence of $SO_2$ and $H_2O$. The long-term isothermal studies at $550^{\circ}C$ under oxygen rich condition showed the superior catalytic properties of the both alkali promoted samples. The crucial catalytic properties of materials are attributed to NO adsorption properties detected by the NO TPD.

• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.35-43
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• 2005

The purpose of this study is to suggest computer assisted neck-base's landmark identification algorithms and measurement extraction methods from three-dimensional human scan data. So we developed the algorithms for automatic identification of landmarks related to the neck-base types. The subjects were 58 women $18{\sim}24$ years of age. Their body were measured directly and indirectly by using camera and three-dimensional body scanner. They were measured during the months of October in 2001. Based on the characters of classified neck-base types, algorithms for the automatic identification of landmarks and methods of automatic measurement are developed. The three-dimensional automatic measuring program is made by $C^{++}$ language. Using this program, 4 landmarks are identified and 6 items are measured. In the verifying the precision of automatic measurement, the height measurements(cervicale, side neck point, front neck point) were relatively accurate, but neck-base width measurement was measured wide.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.206-209
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• 2003

AC loss is an important issue in the design of high-T$_{c}$ superconducting power cables which consist of a number of Bi-2223 tapes wound on a former. In the cables, the tapes have different critical currents intrinsically. And they are electrically connected to each other and current leads. These make loss measurements considerably complex, especially for short samples of laboratory size. So special cautions are required in the positioning of voltage leads for measuring the true loss voltage. In this work we have prepared a conductor composed of three Bi-2223 tapes with different critical currents. The ac loss characteristics in the conductor have experimentally investigated. The loss tests indicate that the ac loss is dependent on arrangements of voltage leads but not on their contact positions. The measured losses in the conductor also agree well with the sum of the transport losses measured in each Bi-2223 tape.e.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.7-10
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• 2003

AC loss is an important issue in the design of high-T$_{c}$ superconducting power cables which consist of a number of Bi-2223 tapes wound on a former. In the cables, the tapes have different critical currents intrinsically. And they are electrically connected to each other and current leads. These make loss measurements considerably complex, especially for short samples of laboratory size. So special cautions are required in the positioning of voltage leads for measuring the true loss voltage. In this work we have prepared a conductor composed of three Bi-2223 tapes with different critical currents. The ac loss characteristics in the conductor have experimentally investigated. The loss tests indicate that the ac loss is dependent on arrangements of voltage leads but not on their contact positions. The measured losses in the conductor also agree well with the sum of the transport losses measured in each Bi-2223 tape.e.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.2
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• pp.161-167
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• 2005

The improvements of the propulsive engine efficiencies could reduce the fuel consumption. Therefore. for a marine main diesel engine the substantial increase of stroke bore ratio. so that the engine speed can be significantly reduced in order to increase the Propulsive efficiency. As a typical example. a Sulzer RTA 60C engine has acylinder diameter of 600 mm and each cylinder is capable of delivering 2.369 kW in the speed range 91-114 rpm. In order to Provide basic data for thermal system of marine engine. this work performs an experimental study of heat transfer in a square channel with one rib-roughened wall under sin91e mode of reciprocating oscillation. A selection of heat transfer measurements illustrates the manner by which the reciprocating channel with two opposite heating walls has the higher heat transfer Performance than with four heating wall.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.192-192
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• 2009

AZO films were prepared by $Ar:H_2$ gas RF magnetron sputtering system with a AZO (2wt% $Al_2O_3$) ceramic target at a low temperature of $100^{\circ}C$. To investigate the influence of $H_2$ flow ratio on the properties of AZO films, $H_2$ flow ratio was changed from 0.5% to 2%. As a result, the AZO films deposited with 1% $H_2$ addition showed electrical properties with a resistivity of $5.06{\times}10^{-3}{\Omega}cm$. The spectrophotometer-measurements showed the transmittance of 86.5% was obtained by the film deposited with $H_2$ flow ratio of 1% in the range of 940nm for GaAs/GaAlAs LED.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.760-761
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• 2010

As is widely known, SPL measurement using sound level meter (SLM) is limited to higher than 30 dBA, because of the self-noise n(x) of condenser microphone (CM). The authors confirmed n(x) is composed of 3 kinds, each of which is stable enough under the condition -20 ~ +50 deg C to eliminate the influence of n(x) by subtracting its energy from the squared input signal in the integration process, as well as to develop new type of SLM with ultra-low SPL measuring function. This is so-called "0-dB SLM" since it enables to measure SPL down to around 0 dB-SPL. The RMS of n(x) is acquired and stored in ROM in advance, by placing CM in the supersilent space or by using dummy microphone with equivalent capacitance before the actual measurements.

• Journal of the Korean Society of Combustion
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• v.8 no.4
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• pp.1-8
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• 2003

In this study, the quantification of soot particles in laminar diffusion flame with LII/LIS methods was performed. In these quantification, soot diameter, number density and volume fraction are included. For the quatification of soot particles, calibration tests are needed and the development of algorithm has to be performed. So, in this study, extinction and scattering test at co-flow burner were performed to acquire calibration data. And algorithm for LII/LIS simultaneous measurement for the quantification of soot were developed. The algorithm, which was the quantification of simultaneous photographing using one ICCD camera, to measure LII/LIS signal simultaneously, the best fitted light intensity and acquisition time was needed.