• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1275-1282
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• 2012

This paper proposes the 16-channel LED Driver IC for Full color LED display system. The proposed LED driver IC in this paper can draw current independent of temperature and supply voltage in each channel. Current flow in the channel is configurable via an external resistor. LED brightness is adjusted by 12-Bit PWM(Pulse Width Modulation) and 8-Bit DC(Dot Correction). A real-time monitoring of IC temperature ($130^{\circ}C/150^{\circ}C$) and LED status (open/short) is provided by LED driver IC and the user can receive warning and get information on problems. A 16-channel LED driver IC is produced using 0.35 um BCD process and the size is $2.5mm{\times}2.5mm$. In this paper, channel current characteristic and channel current control function were measured in order to verify am embodied 16-channel LED driver IC by producing a single IC test board.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.401-402
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• 2006

All-surface, all-tooth machining and roll forming of cast iron have been used to manufacture the crankshaft position sensor wheel (CPSW). However, these methods pose many problems such as difficult processing, high material cost, and low tooth precision. Thus, we developed a sintered CPSW with an improved detection ability in order to resolve the problems related with the previous methods of manufacturing CPSW by simplifying the process flow and improving tooth precision. The sintering process is introduced in this study. We conducted an experiment to compare the sintered and roll formed products and analyzed the results to evaluate the reliability of the sintering process. Furthermore, we compared and analyzed stress and displacement in the sintered and roll formed products through the "Finite Element Method(FEM)". According to the experimental and FEM results, the sintered product showed satisfactory mechanical properties. It was less expensive to process and lighter and showed better quality than the roll formed product. The results of this study could be applied to design an optimum CPSW using the sintering process.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.196-203
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• 2015

BACKGROUND: Purpose of this research is HPLC analysis method development of lycopene in tomato. And then, three components of carotenoid in four kinds of tomatoes (general tomato, cherry tomato, red and orange date tomato) were compared with each other. METHODS AND RESULTS: Lycopene in tomato was extracted with hexane likes other carotenoid components using 500 mg of dried powder sample. HPLC analysis conditions were column temperature ($40^{\circ}C$), detection wavelength (454 nm), flow rate (1.0 mL/min) and injection volume ($20.0{\mu}L$). Lycopene was analyzed by the gradient elution ($60{\rightarrow}100%$) of the mobile phase solvents A[water: methanol=25: 75 (v/v)] and B[ethyl acetate]. CONCLUSION: Three components of carotenoids (lutein, ${\beta}$-carotene, lycopene) were observed in tomatoes. The total carotenoid contents was the highest in red date tomato (662.0 mg/kg dry wt.) and the lowest in orange date tomato (111.3 mg/kg dry wt.). Lycopene contents in tomatoes was the highest percentage (93%) among all the carotenoids.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.173-175
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• 2002

In general, CT and Shunt have been traditionally used as a sensor for detecting the partial discharges in order to diagnose the present insulation state of the electric power apparatus. The former is very convenient for the practical application since it is not only non-contact method but its frequency bandwidth and resonance frequency could be designed for its specific application. However, it has been proved to have poor linearity and low sensitivity. For the latter, even though it is an ideal sensor, noise from the power source and the ground could flow into the system. Furthermore, the surge current could be easily come into the measuring systems giving rise to a severe breakdown. In this respect, a hybrid sensor has been designed and fabricated in order to overcome the shortcoming of these two types of sensors. For this purpose, the experimental comparison with commercialized products has been also carried out. In this concept of the hybrid sensor, two different impedances could provide the passage of the signals. In this way, the discrimination of the noise could be accomplished very effectively with high ratio of signal over noise(S/N) under the little influence from the external noises and the breakdown.

• Natural Product Sciences
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• v.22 no.2
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• pp.77-81
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• 2016

A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of three antibacterial flavonoids, artocarpanone, artocarpin, and cycloartocarpin in ethyl acetate extracts from Artocarpus heterophyllus heartwoods. Separation was achieved using a TSK-gel ODS-80Tm column ($5{\mu}m$, $4.6{\times}150mm$) at $25^{\circ}C$ with a gradient elution system of methanol and water as follows: 0-8 min, 60:40; 8-27 min, 80:20; 27-35 min, 60:40, v/v, at a flow rate of 1 mL/min, and a quantitative UV detection at 285 nm. The method was validated by measuring the key parameters, including specificity, linearity, sensitivity, accuracy, repeatability and reproducibility. A high degree of specificity and sensitivity was achieved. The calibration curves for all three flavonoids showed good linearity with a coefficient of determinations ($R^2$) of ${\geq}0.9995$. The recoveries of the method were from 98-104%, with good reproducibility and repeatability (RSD values of less than 2%) were also achieved. Ethyl acetate was the best solvent for extraction of these three flavonoids using the heat reflux conditions for 1 h. This optimized sample preparation and HPLC method can be practically used for a routine standardization process of the extracts from the A. heterophyllus heartwoods.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.240-245
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• 2011

A high-performance liquid chromatography (HPLC) method was developed for quantitative analysis of liquiritin and glycyrrhizin in Sagunja-tang (SGT, Sijunzi-tang in Chinese), a traditional Korean medicine. HPLC analysis was performed using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array (PDA) detection at 254 nm and 280 nm for quantification of the two components in SGT. The mobile phase using a gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. Calibration curves were acquired with $r^2$ values > 0.9998, and the relative standard deviations (RSDs, %) for intra- and inter-day precision were not exceed 4.0%. The recovery of each component was in the range of 91.85 - 108.62%, with a RSD less than 4.0%. The contents of the two components in SGT were 7.94 - 13.83 mg/g.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.6
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• pp.609-620
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• 2002

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. However, the ultimate temperature rise and the rate of temperature rise is related to the nature of the material, conditions of the test and also to the deformation behaviour of the material during loading. The recent advances in infrared sensors and image/data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been used to characterise the tensile deformation in AISI type 316 nuclear grade stainless steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which the point and time of strain localization could be identified. The technique makes it possible to visualise the region of deformation and failure and also predict the exact region of fracture in advance. The effect of thermal gradients on plastic flow in the case of interrupted straining revealed that the interruption of strain and restraining at a lower strain rate not only delays the growth of the temperature gradient, but the temperature rise per unit strain decreases. The technique is a potential NDE tool that can be used for on-line detection of thermal gradients developed during extrusion and metal forming process which can be used for ensuring uniform distribution of plastic strain.

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.53-63
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• 2001

The individual rotten water purification tank recently discharges wastewater and sewage through the outlet without purification ability. The outlet water and affiliated water purification tank with microorganism cultivator tank cultivates microorganism and then drops the value BOD, COD of sewage and discharges the quality of water into the outlet. The blower and water pump operating continuously prompts the waste of energy and deterioration of equipment. Each room of deposition tank, foaming tank, microorganism cultivator tank is equipment with the sludge detection senses so it can detect the density of each room. The power-drive plant of the blower and water pump which are the system cultivating the microorganism must be made as fuzzy controlization (If the sludge amount of each room become higher, the rate of operation of blower and water pump must heighten, on the contrary, in case of row sludge amount, the total handling amount and microorganism handling amount of each room of control. Tank reducing the rate of operation must be DB. At present, the blower amount in proportion to the sludge and oxyzen demanding amount has to control. Each room mus be checked outlet level of the outlet, also each room must flow backward discharge materials, and must operate feed-back control until we want to be come as a below value of BOD/COD(10PPM ; KS).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.10
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• pp.889-894
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• 2004

Infrared (IR) detectors are widely used for many applications, such as temperature measurement, intruder and fire detection, robotics and industrial equipment, thermoelstic stress analysis, medical diagnostics, and chemical analysis. Quantum detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Thermal analysis of cryochamber includes the conduction heat transfer through a cold well, the gases conduction and gas outgassing, as well as radiation heat transfer, The transient cooling characteristics of an infrared detector cryochamber are investigated experimentally in the present study. The transient cooling load increases as the gas pressure is increased. Gas pressure becomes significant as the cooling process proceeds. Cool down time is also increased as the gas pressure is increased. It is also found that natural convection effects on cool down time become significant when the gas pressure is increased.

• Macromolecular Research
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• v.17 no.3
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• pp.192-196
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• 2009

Recently, the multi-screening of target materials has been made possible by the development of the surface plasmon resonance (SPR) imaging method. To adapt this method to biochemical analysis, the multi-patterning technology of protein microarrays is required. Among the different methods of fabricating protein microarrays, the microfluidic platform was selected due to its various advantages over other techniques. Microfluidic devices were designed and fabricated with polydimethylsiloxane (PDMS) by the replica molding method. These devices were designed to operate using only capillary force, without the need for additional flow control equipment. With these devices, multiple protein-patterned sensor surfaces were made, to support the two-dimensional detection of various protein-protein interactions with SPR. The fabrication technique of protein microarrays can be applied not only to SPR imaging, but also to other biochemical analyses.