• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7A
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• pp.545-551
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• 2012

In this paper, K-band multi-channel receiver was designed and fabricated for low noise amplification and down conversion to L-band. The fabricated multi-channel receiver incorporates GaAs-HEMT LNA(Low noise amplifier) which provides less than a 2 dB noise figure, IR(Image Rejection) Filter for rejection of image frequency, IR(Image rejection) mixer to reject a image frequency and improve an IMD(Intermodulation Distortion) characteristic. Test results of the fabricated multi-channel receiver show less than a 3.8 dB noise figure, conversion gain of more than 27dB, and IP1dB(Input 1dB Gain Compression Point) of -9.5 dB and over.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.562-570
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• 2019

To develop natural-tasting fish paste from the pufferfish Lagocephalus wheeleri, steamed pufferfish paste (SPP) was prepared and its optimal processing conditions, quality metrics, and shelf-life characteristics were examined. SPP was produced by thawing golden threadfin Nemipterus virgatus surimi (FA grade), then adding 10% unwashed pufferfish surimi (PS), 1.5% salt, 8.0% wheat starch, 0.25% calcium carbonate, 0.25% sugar, 0.75% sorbitol, 0.25% polyphosphate, and 12.0% pufferfish hot-water extract (Brix 10°). The meat was ground with a Stephan mixer, molded at low temperature (18℃, 10 h), vacuum packed in a laminated plastic film bag, heat treated with hot water (95℃, 50 min), and cooled. As the amount of PS added increased, the whiteness, gel strength, and shear strength of the SPP decreased slightly. However, the SPP folding test showed no deterioration in the texture. In the sensory evaluation, the SPP received a higher rating for taste, smell, and overall taste than commercial Japanese pufferfish Kamaboko. The total amino acid content of the SPP was 10,262.6 mg/100 g; the major amino acids were aspartic acid, glutamic acid, alanine, valine, leucine, lysine, and arginine. The free amino acid content was 133.0 mg/100 g; the major amino acids were taurine, glutamic acid, glycine, alanine, cystine, and lysine.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.1-11
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• 2007

The process of Cheonggukjang powderization and application to the western food recipes were established. Cheonggukjang was made and processed into the powder. The optimum condition of Cheonggukjang solution for the powdering process was 50%(w/w). And it was completely grinded by a mixer. Drying condition of a spray dryer was to be injected 1 mL/sec. in $105^{\circ}C$ with 3,000 rpm. The components of Cheonggukjang were 49.7 g/100 g of moisture, 2.6 g/100 g of crude ash, 16.2 g/100 g of crude carbohydrate, 23.4 g/100 g of crude protein, 8.1 g/100 g of crude fat, and 9.3 g/100 g of cellulose. The major amino acid was glutamic acid and its quantity was 4,345.5 mg/100 g. And the next were aspartic acid (2,539.2 mg/100 g) and leucin (1,963.2 mg/100 g). In application, 4 kinds of soup recipes using Cheonggukjang powder were developed. The sensory test showed the acceptability between the soup with the powder and the soup without the powder was significant at odor(p<0.05) in vegetable cream soup and broccoli soup, and at taste(p<0.01) in vegetable cream soup. And the soup with non powder showed more acceptability.

• Journal of Power System Engineering
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• v.22 no.1
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• pp.48-55
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• 2018

It has recently been reported that methanol fuel has been used in the product carrier with established duel fuel engine, which has been greatly reducing emissions of $CO_2$, NOx and SOx from the engine. However, to use methanol alone as fuel oil in a general diesel engine, design modification of cylinder head is needed because the ignition aid device or the duel fuel injection system is needed. On the other hand, only if the mixer is installed on the fuel oil supply line, diesel oil - methanol blending oil can be used as fuel oil for the diesel engine, but there is a problem of the phase separation when two fuels are mixed. In this study, diesel oil and methanol were blended compulsorily in preventing the phase separation with installing agitators and a fuel oil boost pump on fuel line of a test engine. Also, cylinder pressure and fuel consumption quantity were measured according to engine load and methanol blending ratio, and indicated mean effective pressure, heat release rate and combustion temperature obtained from the single zone combustion model were analyzed to investigate the effects of latent heat of vaporization of methanol on combustion stability and characteristics. As a result, the combustion stability and characteristics of 10% methanol blending oil are closest to the those of diesel oil, and it could be used as fuel oil in existing diesel engines without deterioration of engine performance and combustion characteristics.

• Elastomers and Composites
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• v.48 no.1
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• pp.18-23
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• 2013

Nylon 12 elastomer was slightly crosslinked in molten state by the addition of small amount of dicumyl peroxide (DCP) as a crosslink agent and triallycyanuate (TAC) as a co-agent during melt compounding at $160^{\circ}C$ in an internal mixer. The effect of the peroxide crosslinking on mechanical, dynamic mechanical and rheological properties of the nylon 12 elastomer was investigated by means of tensile testing, dynamic mechanical analysis (DMA) and small amplitude oscillating rheometer, respectively. With modification, there is an improvement in tensile modulus and Young's modulus with decease in elongation at break. DMA results for peroxide modified nylon 12 elastomers demonstrated that the glass transiaiton temperature of PTMG segment shifted to higher temperature and the storage modulus remained constant above the melting temperature of nylon 12 segments. Melt rheological studies revealed that the peroxide modified nylon 12 elastomer exhibited a more solid like behavior and stronger shear thinning behavior compared to neat nylon 12 elastomer, which was more prominent at higher TAC content in the polymer matrix. The peroxide modified nylon 12 elastomer exhibited good elastic recoverability and improved mechanical properties without sacrificing melt processibilty, and especially the service temperature range increased as compared to neat nylon 12 elastomer.

• Plant Journal
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• v.18 no.3
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• pp.52-61
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• 2022

This study tested the effect of de-NOx Facility operating condition on Nox emisiion in a 125 MW wood pellet power plant in Yeongdong Eco Power Plant Unit 1, which is in operation. As SNCR urea flow rate increased, NOx emission gradually decreased, but ammonia slip after SCR increased. The boiler under test has a structure that is unfavorable to SNCR operation due to the high internal temperature, and the optimum location of the nozzle will be required. SCR dilution air temperature change did not affect the amount of NOx generated. Increasing SCR ammonia flow reduced the NOx emission at SCR outlet and also increased the NOx removal efficiency. However, the ammonia flow rate of 111 kg/h, which does not exceed the ammonia slip its own reference limit, is estimated to be the maximum operating standard. The increase in SCR mixer pressure reduced NOx emission and the removal efficiency was also measured to be the most effective variable to inhibit NOx production.

• Resources Recycling
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• v.31 no.6
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• pp.66-72
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• 2022

The circularity and particle size distribution of products obtained from dry classification after circularity tests using a high-intensity mixer were investigated to evaluate the use of domestic graphite concentrate as a lithium-ion battery material. At a rotor speed of 3,000 rpm, the particle size and circularity of the concentrated sample and product were unchanged. The circularity increased and particle size decreased when the rotor speeds were increased to 6,000 rpm, 10,000 rpm, and 12,000 rpm and the operating time was increased. For instance, the circularity increased from 0.870 to 0.936 when the rotor speed was increased from 3,000 rpm to 12,000 rpm for an operating time of 10 min. After the circularity test, dry classification was performed, wherein the circularity of the coarse particles was found to have increased to 0.947. Round particles were observed in the SEM images, indicating that high circularity was successfully achieved.

• Clean Technology
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• v.23 no.2
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• pp.133-139
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• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.210-215
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• 2006

In this paper, we develop the PLL system of the local oscillator system using Gunn oscillator VCO for millimeter wave band receiving system. The local oscillator system consists of the $86{\sim}115GHz$ Gunn. diode oscillator part, the RF processing part including the diplexer and the harmonic mixer, and the DPLL system including Gunn modulator and controller. Based on this configuration, we verify the frequency and power stability of the developed local oscillator system. We developed system which applied to DPLL technique instead of the existing analog PLL method to accomplish this purpose. The developed system for this purpose is tested the frequency and power stability for a long time to confirm performance. Since we confirmed this system that had frequency characteristic of within ${\pm}10Hz$, very fine output drift power characteristic of $0.2{\sim}0.3dBm$ and about 200MHz locking range, it verified suitable for cosmic radio receiving system through the test result.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.116-129
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• 2006

The progress of data transmission technology through the Internet has spread a variety of realistic contents. One of such contents is multi-view video that is acquired from multiple camera sensors. In general, the multi-view video processing requires encoders and decoders as many as the number of cameras, and thus the processing complexity results in difficulties of practical implementation. To solve for this problem, this paper considers a simple multi-view system utilizing a single encoder and a single decoder. In the encoder side, input multi-view YUV sequences are combined on GOP units by a video mixer. Then, the mixed sequence is compressed by a single H.264/AVC encoder. The decoding is composed of a single decoder and a scheduler controling the decoding process. The goal of the scheduler is to assign approximately identical number of decoded frames to each view sequence by estimating the decoder utilization of a Gap and subsequently applying frame skip algorithms. Furthermore, in the frame skip, efficient frame selection algorithms are studied for H.264/AVC baseline and main profiles based upon a cost function that is related to perceived video quality. Our proposed method has been performed on various multi-view test sequences adopted by MPEG 3DAV. Experimental results show that approximately identical decoder utilization is achieved for each view sequence so that each view sequence is fairly displayed. As well, the performance of the proposed method is examined in terms of bit-rate and PSNR using a rate-distortion curve.