• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.937-941
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• 2005

The antioxidant and anticancer activities of Styela plicata extracts were evaluated. When extracts were prepared with fresh Styela plicata (FR), extraction yield was in the order of methanol > ethanol = acetone > water among treated solvents. However, the extraction order was methanol > water > ethanol > acetate in freeze dried Styela plicata (FD). Radical scavenging activity was the highest in acetone extracts $(37.39\%)$ from FR, while in ethanol extracts $(78.40\%)$ from FD. Reducing power of FR was the greatest in methanol extracts (1.076), and that of FD in ethanol extracts (1.360). The acetone extracts from FD showed significant anticancer activity when revealed with human colon cancer cell line HT-29. These results indicated that extraction yields and properties of extracts from Styela plicata were variable depending on solvent and/or physicochemical state, and appropriate extraction process could provide some valuable bioactive materials from Styela plicata.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.816-822
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• 2011

Pervaporation is known to be a low energy consumption process since it needs only an electric power to maintain the permeate side in vacuum. Also, the pervaporation is an environmentally clean technology because it does not use the third material such as an entrainer for either an azeotropic distillation or an extractive distillation. In this study, Silicalite-1 particles are hydrothermally synthesized and polydimethylsiloxane(PDMS)-zeolite composite membranes are prepared with a mixture of synthesized Silicalite-1 particles and PDMS-polymer. They are used to separate n-butanol from its aqueous solution. Pervaporation characteristics such as a permeation flux and a separation factor are investigated as a function of the feed concentration and the weight % of Silicalite-1 particles in the membrane. A 1,000 $cm^3$ aqueous solution containing butanol of low mole fraction such as order of 0.001 was used as a feed to the membrane cell while the pressure of the permeation side was kept about 0.2~0.3 torr. When the butanol concentration in the feed solution was 0.015 mole fraction, the flux of n-butanol significantly increased from 14.5 g/ $m^2$/hr to 186.3 g/$m^2$/hr as the Silicalite-1 content increased from 0 wt% to 10 wt%, indicating that the Silicalite-1 molecular sieve improved the membrane permselectivity from 4.8 to 11.8 due to its unique crystalline microporous structure and its strong hydrophobicity. Consequently, the concentration of n-butanol in the permeate substantially increased from 0.07 to 0.15 mole fraction. This composite membrane could be potentially appliable for separation of n-butanol from insitu fermentation broth where n-butanol is produced at a fairly low concentration of 0.015 mole fraction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.336-344
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• 2005

Discrete Wavelet Transform(DWT) is the oncoming generation of compression technique that has been selected for MPEG4 and JEPG2000, because it has no blocking effects and efficiently determines frequency property of temporary time. In this paper, we propose an efficient bit-serial architecture for the low-power and low-complexity DWT filter, employing two-channel QMF(Qudracture Mirror Filter) PR(Perfect Reconstruction) lattice filter. The filter consists of four lattices(filter length=8) and we determine the quantization bit for the coefficients by the fixed-length PSNR(peak-signal-to-noise ratio) analysis and propose the architecture of the bit-serial multiplier with the fixed coefficient. The CSD encoding for the coefficients is adopted to minimize the number of non-zero bits, thus reduces the hardware complexity. The proposed folded 1D DWT architecture processes the other resolution levels during idle periods by decimations and its efficient scheduling is proposed. The proposed architecture requires only flip-flops and full-adders. The proposed architecture has been designed and verified by VerilogHDL and synthesized by Synopsys Design Compiler with a Hynix 0.35$\mu$m STD cell library. The maximum operating frequency is 200MHz and the throughput is 175Mbps with 16 clock latencies.

• Food Science and Preservation
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• v.18 no.4
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• pp.590-596
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• 2011

Pimpinella brachycarpa, called as cham-na-mul in Korea, is an edible popular herb. However, the study of biological activity of P. brachycarpa is still rudimentary in worldwide. In this study, from the cultivated P. brachycarpa, we prepared the methanol extract and its subsequent solvent fractions, and their antimicrobial, antioxidation, and anti-proliferative activities were evaluated. The fraction yields of n-hexane (H), methylene chloride (EC), ethylacetate (EA), butanol (B), and water residue (W) from the methanol extract were 18.71, 0.7, 0.56, 4.57, and 71.51%, respectively. Analysis of total flavonoid and total polyphenol showed that the EA fraction contained the highest contents (89.23 and 200 mg/g), and the W residue has the lowest contents (19.6 and 2.27 mg/g) among the factions. In antimicrobial activity assay, the EA fraction showed a broad-range antibacterial activity, while the H fraction is effective against gram positive bacteria. In antioxidation activity assay, EA and B fraction showed strong DPPH anion and ABTS cation scavenging activities including reducing power, and Hand MC fraction showed effective nitrite scavenging activity (71.43~83.82 ${\mu}g$/mL of $IC_{50}$). In a while, only B fraction showed strong anti-proliferative activity against human colorectal cancer HCT-116 (166 ${\mu}g$/mL of $IC_{50}$) as a dose-dependent manner up to 200 ${\mu}g$/mL. These results suggest that the EA and B fraction of P. brachycarpa could be developed as functional food ingredients.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.5
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• pp.188-192
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• 2016

In this work, the SiC powders were synthesized through the carbonized matter from the mixture of silica powder and rice husks. The SiC powders, obtained from the carbothermal reduction reaction of silica and carbonized rice husks, were investigated by XRD patterns, XPS, FE-SEM and FE-TEM. In the XRD patterns, the specimens showed clearly very high strong peak of (111) plane near $35^{\circ}$ as well as weak (220) and (311) peak respectively at approximately $60^{\circ}$ and $72^{\circ}$. Under Ar atmosphere, the power synthesized from the mixture (in case of mixing ratio, 6 : 4) of carbonized rice husks and silica showed mainly cubic SiC crystalline phase showing relatively lower ratio of hexagonal phase without residual carbon in XRD pattern. In the TEM analysis, the specimen, synthesized from carbonized rice husks and silica with mixing ratio of 6 : 4 under Ar atmosphere, showed relatively fine particles under $5{\mu}m$ and a crystalline SiC phase of (100) diffraction pattern.

• Polymer(Korea)
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• v.33 no.4
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• pp.319-325
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• 2009

The solution polymerization was conducted to synthesize pressure sensitive adhesive for polarizer film using acrylic monomers. 2-Ethylhexylacrylate, butylacrylate, acrylic acid were used as acrylic monomers. The ratio was 2-ethylliexylacrylate:butylacrylate:acrylic acid=25:50:3.6 by reflecting $-40^{\circ}C$ of glass transition temperature in the pressure sensitive adhesive. When 1 wt% of coupling agent was added to the polymerized pressure sensitive adhesive, the light transmissivity was significantly increased. This result is due to the enhancement of adhesive power against liquid crystal cell by Si-O bond of coupling agents. Cross-linking agent was added by 0.5, 1.0, and 1.5 wt% with respect to the synthesized polymer. Initial tackiness decreased, while cohesion increased with increasing crosslinking agent. In the analysis of contact angle, the increase of crosslinking agents yielded the enhancement of surface energy, resulting in the decrease of contact angle. From the measurement of heat resistance, the acrylic pressure sensitive adhesive showed excellent heat resistance regardless of change in temperature and contents in crosslinking agent. In the observation of a cutting plane, the increased crosslinking agent represented a smoother and cleaner section. Comprehensively, the optimum additive amount of crosslinking agent was determined to be 1.0 wt% to monomer.

• Food Science and Preservation
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• v.24 no.1
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• pp.116-124
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• 2017

In this study, we compared the antioxidant and immuno-modulatory effects of water (HR, HL, HS), 70% ethanol (ER, EL, ES), and 70% methanol (MR, ML, MS) extracts of different parts (root, leaf, and seed) from Glehnia Radix. Yields were 17.40-30.17% for water extract, 11.47-28.67% for 70% ethanol extract, and 10.73-30.57% for 70% methanol extract, respectively. The total polyphenol and flavonoid contents of EL were 10.79 g/100 g and 2.01 g/100 g, respectively. The DPPH and ABTS radical scavenging activities of EL at $1,000{\mu}g/mL$ were 84.70% and 57.64%, respectively. The superoxide radical scavenging and ferric-reducing antioxidant power of EL at $1,000{\mu}g/mL$ were 84.05% and $975.28{\mu}M$, respectively. Moreover, 70% ethanol and 70% methanol extracts of root from Glehnia Radix significantly inhibited production of NO in LPS-stimulated macrophage RAW 264.7 cells without cytotoxicity. These results suggest that 70% ethanol and 70% methanol extracts of Glehnia Radix leaf may be a useful functional food material in the food industry.

• Journal of Life Science
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• v.26 no.8
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• pp.928-935
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• 2016

Hypsizygus marmoreus (white cultivar), also called white beech mushrooms, are edible mushrooms commercially cultivated in Korea and Japan. This study was carried out to evaluate the antioxidant properties of H. marmoreus. H. marmoreus fruit bodies were divided into pileus and stipe. The pileus and stipe were extracted into water and 80% ethanol and their antioxidant activities were analyzed. The total polyphenol content was highest in the water extract (pileus 1137.39±0.38 mg of GAE (gallic acid equivalents)/100 g, stipe 700.86±0.06 mg of GAE/100 g) compared to the ethanol extract (pileus 923.47±0.18 mg of GAE/ 100 g, stipe 324.05±0.03 mg of GAE/100 g). Ethanol extracts from pileus showed better scavenging ability on DPPH (47.32±0.23% at 10 mg/ml) and ABTS (57.33±0.10% at 10 mg/ml) than the stipe and water extract groups. Water extract from pileus were more effective in reducing power and ORAC (oxygen radical absorbance capacity) value than stipe and ethanol extract. The toxicity of water and ethanol extracts was investigated using WST-1 (Water Soluble Tetrazolium salt) assay on the mouse macrophage cell line RAW 264.7. Overall, total polyphenol content and antioxidant activities of extracts from H. marmoreus increased in a dose dependent manner while pileus was showed better total polyphenol content and antioxidant activities than stipe.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.184-196
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• 2020

In this paper, a single-bit 2nd-order delta-sigma modulator with the architecture of cascaded-of-integrator feedforward (CIFF) is proposed for precision measurement of current flowing through a secondary cell battery in a battery management system (BMS). The proposed modulator implements two switched capacitor integrators and a single-bit comparator with peripheral circuits such as a non-overlapping clock generator and a bias circuit. The proposed structure is designed to be applied to low-side current sensing method with low common mode input voltage. Using the low-side current measurement method has the advantage of reducing the burden on the circuit design. In addition, the ±30mV input voltage is resolved by the ADC with 15-bit resolution, eliminating the need for an additional programmable gain amplifier (PGA). The proposed a single-bit 2nd-order delta-sigma modulator has been implemented in a 350-nm CMOS process. It achieves 95.46-dB signal-to-noise-and-distortion ratio (SNDR), 96.01-dB spurious-free dynamic range (SFDR), and 15.56-bit effective-number-of-bits (ENOB) with an oversampling ratio (OSR) of 400 for 5-kHz bandwidth. The area and power consumption of the delta-sigma modulator are 670×490 ㎛2 and 414 ㎼, respectively.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.4
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• pp.160-167
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• 2005

Among finite filed arithmetic operations, division/inverse is known as a basic operation for public-key cryptosystems over $GF(2^{m})$ and it is computed by performing the repetitive $AB^{2}$ multiplication. This paper presents a digit-serial-in-serial-out systolic architecture for performing the $AB^2$ operation in GF$(2^{m})$. To obtain L×L digit-serial-in-serial-out architecture, new $AB^{2}$ algorithm is proposed and partitioning, index transformation and merging the cell of the architecture, which is derived from the algorithm, are proposed. Based on the area-time product, when the digit-size of digit-serial architecture, L, is selected to be less than about m, the proposed digit-serial architecture is efficient than bit-parallel architecture, and L is selected to be less than about $(1/5)log_{2}(m+1)$, the proposed is efficient than bit-serial. In addition, the area-time product complexity of pipelined digit-serial $AB^{2}$ systolic architecture is approximately $10.9\%$ lower than that of nonpipelined one, when it is assumed that m=160 and L=8. Additionally, since the proposed architecture can be utilized for the basic architecture of crypto-processor and it is well suited to VLSI implementation because of its simplicity, regularity and pipelinability.