• Food Science and Biotechnology
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• v.18 no.5
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• pp.1145-1149
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• 2009

Physicochemical properties of native and acid-modified Job's tears (Coix lachryma-jobi L.) starches were investigated. Starch extracted from Job's tears was treated with 2.2 N hydrochloric acid for different length of time (3, 6, 12, and 18 hr). The hydrolysis pattern of starches with the acid proceeded rapidly up to 12 hr and then the approached constant values. The swelling power of acid-modified starches measured at all temperatures was lower than that of its native counterparts and the water solubility index increased as temperature and hydrolysis time increased. Rapid visco analyzer viscograms of acid-modified starches demonstrated a very low viscosity as compared with that of native starch. However, Xray diffraction did not show any significant alteration in the crystallinity after acid-modification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.298-305
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• 2004

This paper presents an error compensation method for a fixed-width modified Booth multiplier that receives a W-bit input and produces a W-bit product. To efficiently compensate for the quantization error, Booth encoder outputs (not multiplier coefficients) are used for the generation of error compensation bias. The truncated bits are divided into two groups depending upon their effects on the quantization error. Then, different error compensation methods are applied to each group. By simulations, it is shown that quantization error can be reduced up to 50％ by the proposed error compensation method compared with the existing method with approximately the same hardware overhead in the bias generation circuit. It is also shown that the proposed method leads to up to 40％ reduction in area and power consumption of a multiplier compared with the ideal multiplier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.186-196
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• 2000

In this paper, modified square loop frequency selective surface for dualband communication antenna systems is proposed, and the scattering characteristics is discussed. The analysis for the problem of scattering by periodic structures with a dielectric slab is formulated using the spectral-domain immittance approach and Floquet's theorem. The method of moments which uses rooftop subdomain basis function is employed to solve the equations. Numerical results include the comparison between the transmission characteristic of general square loop and that of modified square loop. Also, the transmission characteristics of modified square loop for arbitrary incident angle and polarization is presented. To verify analysis results, modified square loop frequency selective surface was fabricated and the calculated results were compared with the measured results. The measured results showed good agreement with the calculated results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.9-15
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• 2018

This study investigates a bidirectional quasi-Z-source inverter (Bq-ZSI) system with bidirectional power transfer capability and a modified space vector modulation scheme for reducing the ripple of the inductor current. By replacing the diode in the impedance network with an active switch, the power flow can be bidirectional. The average inductor current of the Bq-ZSI network is negative in the regenerative braking mode, thereby regenerating the power. In addition, modified space vector modulation scheme is applied to the Bq-ZSI to control shoot-through time effectively. A 5 kW prototype is built and tested to implement the proposed system. Experimental results show that the Bq-ZSI system is capable of regenerative braking of the induction motor and that the modified space vector modulation method is efficient.

• Journal of Magnetics
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• v.9 no.4
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• pp.109-112
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• 2004

The HDDR (Hydrogenation-Disproportionation-Desorption-Recombination) process is a special method to produce anisotropic NdFeB powders for bonded magnet. The effect of the modified HDDR process on magnetic properties of $Nd_2Fe_{14}B$-based magnet with several composition $Nd_{11.2}Fe_{66.5-x}Co_{15.4}B_{6,8}Zr{0.1}Ga_x(x=0{\sim}1.0)$ and that of microelement Ga, disproportional temperature and annealing temperature on $_jH_c$, grain size were investigated in order to produce anisotropic powder with high magnetic properties. It was found that modified HDDR process is very effective to enhance magnetic properties and to fine grain size. The addition of Ga could change disproportionation character remarkably of the alloy and could improve magnetic properties of magnet powder. Increasing annealing temperature induces significant grain growth. And grain size produced by modified HDDR process is significantly smaller than those produced by conventional HDDR process.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.39-47
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• 2014

Daylighting has a great effect on people inside the room. It is also closely related to the lighting energy consumption. Daylight factor(DF) is a very important index for evaluation of the daylighting in overcast sky. The objective of this study is to verify the suitability of the Tregenza's Modified Split Flux formula for the calculation of the daylight factor. We compared the daylight factors calculated by two methods; one by a measurement with 1/5 scale model and the other by the Daysim program. We used variables for verification as window wall ratios(WWR) and angles of the sky visible. As a result, daylight factor calculated by Modified Split Flux is similar to the measurement when more daylight enters the inside. And error is significantly increased when the angle of the sky visible is $50^{\circ}$.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.73-81
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• 1998

In order to stabilize the price of fresh ginseng by extension of seasonal variation and marketing structure, and to reduce the cost of production by works of intensive and short term, studies were carried out. As fresh ginseng of 4 years old by the MA (modified atmosphere storage) and CA (controlled atmosphere storage) was stored for 12 week at 4$^{\circ}C$, samples were collected after every 1, 2, 3, 4, 6, 8, 12 weeks for processing red ginseng. Chemical characteristics on ginseng steamed red for the quality evaluation are summarized as follows. The composition of free sugar was consisted of fructose, glucose, sucrose, and maltose in fresh ginseng. And small change was revealed in free sugar composition during the storage period. Glucose and sucrose were largely increased in both treatments of MA (modified atmosphere storage) and CA (controlled atmosphere storage) after 4 week, wherein maltose was decreased. Fifteen different amino acids were identified, and total amount of histamine and arginine were over 40%. Phenylalanine was slightly decreased. As the volatile components in control red ginseng, six different ones including triisopropyl benzene were detected. B-1 ($CO_2$ : $O_2$ : N2=6 : 4.90, DF-100) of CA and E-1 (CPP, DF-100) of MA did not shown triisopropyl benzene as the volatile components. And ${\gamma}$-muurolene, guaiaene, and beta-patchoulene were reduced, but the other components showed the trend of increase.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.101-111
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• 2017

The objective of this study is to determine the effectiveness of a modified air-side economizer in improving indoor air quality (IAQ). An air-side economizer, which uses all outdoor air for cooling, affects the building's IAQ depending on the outside air quality and can significantly affect the occupants' health, leading to respiratory and heart disease. The Air Quality Index (AQI), developed by the US Environmental Protection Agency (US EPA), measures air contaminants that adversely affect human beings: PM10, PM2.5, SO2, NO2, O3, and CO. In this study, AQI is applied as a control for the operation of an air-side economizer. The simulation is analyzed, comparing the results between the differential enthalpy economizer and AQI-modified economizer. The results confirm that an AQI-modified economizer has a positive effect on IAQ. Compared to the operating differential enthalpy economizer, energy increase in an operating AQI-modified economizer is 0.65% in Shanghai and 0.8% in Seoul.

• Macromolecular Research
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• v.16 no.1
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• pp.21-30
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• 2008

Based on the sheath-core bicomponent composite fibers with modified polystyrene (PS) and the modified polypropylene (PP), composite fibers obtained were further cross-linked and sulphonated with chlorosulphonic acid to produce strong acidic cation ion exchange fibers. The structures of the fibers obtained were characterized using Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) etc. The optimal technology of the fibers obtained is discussed. The static absorption capacity of the sheath-core bicomponent composite cation exchange fibers for $Zn^{2+}$, $Cu^{2+}$ was determined. The absorption kinetics and major factors affecting the absorption capacities of $Zn^{2+}$, $Cu^{2+}$ were studied, and its chemical stability and regenerating properties were probed. The results suggest that cation exchange fibers with better mechanical properties and higher exchange capability were obtained. Moreover, this type of ion exchange fiber has good absorption properties and working stability to various metal ions. Hence, they have higher practicability.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.4
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• pp.318-327
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• 2000

Sludge production from water treatment plants is increasing each year because water resources deterioration is proceeding and water supply facilities are growing due to water demand increase. Water treatment plant sludges can be modified to soil cover in sanitary landfilling site through the lime treatment and other alternatives. The compression strength of $1.0kg/cm^2$ is necessary for the dozer operation on soft son cover material at municipal landfilling site. Modified sludge was experimentally produced in this study with lime, bentonite, loess, and activated loess dosing. X-ray diffraction patterns of the limed water treatment plant sludge confirmed the presence of calcium carbonate and ettringite. Unconfined compression strength properties of modified sludges showed material property improvement applicable for soil cover alternatives. When adding 20-30% activated loess to water treatment plant sludges. the modified sludges could reach the compression strength for cover soil after 7 days solidification reaction, but decrease of compression strength was intentioned in 28 days reaction period. Solidification effect of the modified sludge with activated loess was observed through the scanning electron microscope.