• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.1
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• pp.14-19
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• 1982

A differential amplifier has been designed and fabricated using aluminum-gate PMOS technology, Only enhaneement-mode MOSFET's are used in the circuit and the dimensions of transistors have been determined using simulation program MSINC. The fabricated integrated circuit with +15V and -l5V power supplies shows an open-loop DC voltage gain of 42 dB, a common mode rejection ratio (CMRR) of 50 dB, and a Power consumption of 20mW.

• Nuclear Engineering and Technology
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• v.22 no.2
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• pp.108-115
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• 1990

The measurements of X-ray production cross-sections for 0.5~1.2-MeV proton beam are carried out on Cu and Au. For this experiment, the proton tram generated from the SNU 1.5-MV Tandem Van do Graaff accelerator is Incident on the target. The X-rays and the backscattered protons from the irradiated target are detected simultaneously by the Si(Li) X-ray detector and the SSB (Silicone Surface Barrier) charged particle detector The measured values of X-ray production cross-sections are compared with other experimental values and theoretical values such as the PWBA (Plane Wave Born Approximation) and the ECPSSR(Perturbed Stationary State corrected Energy loss, Coulomb deflection, Relativistic effects) values. For measured cross-sections near 1.0- MeV proton energy, the ECPSSR (D.D. Cohenet al., 1985) shows better agreement than the PWBA. Particularly, that of Au for 1.2 MeV proton beam is 9.69$\pm$ 0.39 barns which deviates from the ECPSSR by less than 5%. and the experimental data for 0.5~1.2- MeV proton agree with most of other experimental values within 30%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.259-268
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• 2012

This study measured the natural-convection heat transfer of two vertically staggered cylinders with varying vertical pitch-to-diameter ($P_v$/D) and horizontal pitch-to-diameter ($P_h$/D) ratios. The measured heat-transfer rates for the lower cylinder agreed well with the existing heat-transfer correlations for a single cylinder. At the smallest $P_v$/D, the rising plume from the lower cylinder provides the upper cylinder with a preheated flow, and the heat-transfer rates of the upper cylinder decrease, but increase very sensitively with $P_h$/D. However, at the largest $P_v$/D, the velocity effect dominates, and the heat-transfer rates of the upper cylinder are larger than that of a single cylinder, and decrease less sensitively with $P_h$/D. Even if $P_h$/D is increased, the heat-transfer rate of the upper cylinder is higher than that of the lower cylinder because of the chimney and side flow effects. This work expanded the flow ranges to turbulent flows. The cupric acid-copper sulfate ($H_2SO_4-CuSO_4$) electroplating system was adopted for the measurements of the mass-transfer rates instead of the heat-transfer experiments based on the analogy concept. The measurements were made by varying $P_v$/D (1.02-5) and $P_h$/D (0-2) in both laminar and turbulent flows. The Rayleigh number ranged from $1.5{\times}10^8$ to $2.5{\times}10^{10}$, and the Prandtl number was 2,014.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.4
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• pp.409-412
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• 2002

The LNA(Low Noise Amplifier) is designed for use in low cost commercial application covered fully IMT-2000 band(1920~2170MHz, BW=250MHz). It is optimized source inductance for source lead and designed to equivalent etched line. The LNA uses a high pass impedance matching network for noise match and simple structure. The bias circuit designs have been made self-biased with a negative voltage applied to gate. The power supply voltage is 8V, total current is 180mA. The LNA is biased at a Vgs of -0.4, Vds of 4V for first stage and Vds of 5V for second stage. The LNA is designed competitively for commercial product specification. The measured gain and noise figure of the completed amplifier was 20dB and 1dB, respectively. Also, input VSWR, P1dB and gain flatness was measured of 1.14 ~ l.3dB, 22.4dBm and $\pm$0.45dB, respectively. The designed LNA can be used for commercial product.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.35-49
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• 2003

In this study, in an attempt to search for functional cosmetic ingredients from higher fungal, we have produced exopolysaccharides (GF-l, approximately carbohydrate 75％, protein 25％) and polysaccharide (GF-2) of mycelium extract, by submerged culture of Grifolafrondosa. For applications in anti-aging cosmetic field, we investigated the diverse biological activities. Antioxidant activity and inhibition of Matrixmetalloproteinases (MMPs) were investigated enzymatic assays by measuring the superoxide scavenging activity using xanthine-xanthine oxidase system and the proteolytic activity of MMPs using EnzChek Collagenase/Gelatinase kits, respectively. GF-l polysacchairde showed inhibition of superoxide radical by 90％ at a concentration of 0.2％ (w/v) and inhibition of collagenase by 45％ at 0.2％ (w/v). GF-2 polysaccharide of mycelium extract also exhibited good antioxidant activity. However, MMPs inhibition activity was relatively lower level compared to GF-l polysaccharides. The treatment of human dermal fibroblast (HDF) with GF-l and GF-2 polysaccharides increased the proliferation of fibroblast by approximately 23-25％ at a concentration of 0.5％ (w/v), also showed collagen synthesis increase in HDF by about 50％ at 0.5％ (w/v) compared to that of untreated control. We also report the moisturizing effects of polysaccharides in cosmetic products (O/W emulation) and its own ingredient, in vitro and in vivo. The GF-1 polysaccharide showed higher moisturizing ability than sodium hyaluronate, which is the most commonly used moisturizers ingredient. These results suggest the GF-l polysaccharide, protein-bound polysaccharide, may be used as an ingredient for new moisturizing and anti-aging cosmeceuticals.

• Analytical Science and Technology
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• v.20 no.2
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• pp.109-114
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• 2007

In this study, soxhlet extraction and dissolution-precipitation method are used for separating analyte from polymer materials. In soxhlet extraction efficiency test, it has been found that the DCM, Toluene, THF, and mixtures Acetone/Hexane (1:4, v/v) gave good extraction efficiency, while the use of the ethyl ether, acetone/ethyl ether (1:4, v/v), acetone/hexane (1:1, v/v), DCM/hexane (1:1, v/v) resulted in significantly lower values. In case of dissolution-precipitation method, there is no considerable difference with used different dissolving solvent. The elution amount of multi layer silica and Florisil column were determined with hexane 250 mL and 70 mL of hexane, respectively. Range of PBDE in real waste plastics was N.D.~1,028 ppm.

• Journal of the Korean Chemical Society
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• v.44 no.2
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• pp.102-108
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• 2000

Relative retention times (RRTs) of RAH molecules in HPLC are trained and predicted intesting sets using a multiple linear regression (NLR) and an artificial neural network (ANN). The maindescriptors in QSRR are molecular connectivity ($^1X_v,\;^2X_v$), the length-to-breadth ratios (L/B), and molecular dipole moment(D). L/B which is related with slot model is a good descripter in ANN, but isn't in MLR. Varainces which show the accuracy of prediction times in testing sets are 0.0099, 0.0114 for ANN and MLR, respectively. It was shown that ANN can exceed the MLR in prediction accuracy.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.195-198
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• 1996

This paper is studid the flow analysis of cardio vascular assist device. The experimental study is carried out to measure velocity profiles, Shear stress distributions and Velocity Vector for the flowrare of 4l/min, the frequency of 0.5Hz, the stroke volume of 60ml, the inlet and outlet pressure of 100mmHg by the L.D.V and P.I.V system. These results are agreed with the numerical simulations.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.449-456
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• 2023

In this study, we developed Rapid Enrichment Broth for Vibrio parahaemolyticus (REB-V), a broth capable enriching V. parahaemolyticus from 10⁰ CFU/mL to 10⁶ CFU/mL within 6 hours, which greatly facilitates the rapid detection of V. parahaemolyticus. Using a modified Gompertz model and response surface methodology, we optimized supplement sources to rapidly enrich V. parahaemolyticus. The addition of 0.003 g/10 mL of D-(+)-mannose, 0.002 g/10 mL of L-valine, and 0.002 g/10 mL of magnesium sulfate to 2% (w/v) NaCl BPW was the most effective combination of V. parahaemolyticus enrichment. Optimal V. parahaemolyticus culture conditions using REB-V were at pH 7.84 and 37℃. To confirm REB-V culture efficiency compared to 2% (w/v) NaCl BPW, we assessed the amount of enrichment achieved in 7 hours in each medium and extracted DNA samples from each culture every hour. Real-time PCR was performed using the extracted DNA to verify the applicability of this REB-V culture method to molecular diagnosis. V. parahaemolyticus was enriched to 5.452±0.151 Log CFU/mL in 2% (w/v) NaCl BPW in 7 hours, while in REB-V, it reached 7.831±0.323 Log CFU/mL. This confirmed that REB-V enriched V. parahaemolyticus to more than 10⁶ CFU/mL within 6 hours. The enrichment rate of REB-V was faster than that of 2% (w/v) NaCl BPW, and the amount of enrichment within the same time was greater than that of 2% (w/v) NaCl BPW, indicating that REB-V exhibits excellent enrichment efficiency.

• Journal of Pharmacopuncture
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• v.4 no.3
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• pp.47-57
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• 2001

Objective: This study is performed for the purpose of examining into the efficacy of the scolopendrid(Scolopendra morsitans L) which has been used among the Korean people for the H.I.V.D of lumbar spine. Methods & Results: Using the herbal acupuncture made of scolopendrid(Scolopendra morsitans L), we treated the 10 H.l. V.D patients for 1 week and operated 4 pre and post treatment test ; D.I.T.I, 6 kind of physical test, Oswestry disability index, and self-conscious pain rate. Trough Lite test, we saw 50-100% of efficacy rate in each test. Otherwise, only 5 of the 7 point in D.I.T.I and self-conscious pain rate showed statistically valuable change. Conclusion: we brought to the conclusion that the scolopendrid herbal acupuncture has possibility to be efficient to cure the H.I.V.D patients. So we suggest the possibility to use this new remedy for the H.I.V.D.