• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.465-471
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• 2009

To prevent the explosive spalling of the high strength concrete and control the rise of temperature in the steel rebar during fire, a fiber cocktail method has been proposed simultaneously with the use of polypropylene and steel fiber. After applying the fiber cocktail (polypropylene and steel fibers) into the mixture of high strength concrete with a compressive strength of between 40 and 100 MPa and evaluating the thermal properties at elevated temperatures, the fire test was carried out on structural members in order to evaluate the fire resistance performance. Two column specimens were exposed to the fire without loading for 180 minutes based on the standard curve of ISO-834. No explosive spalling has been observed and the original color of specimen surface was changed to light pinkish grey. The inner temperature of concrete dropped rapidly starting from 60mm deep. After 60 minutes of exposure to the fire, the temperature gradient of fiber cocktail reinforced high strength concrete was measured as 2.2oC/mm, which is approximately 5 times less than that of normal concrete. The final temperatures of steel rebar after 180 minutes of fire test resulted in 488.0oC for corner rebar, 350.9oC for center rebar, and 419.5oC for total mean of steel rebar. The difference of mean temperature between corner and center rebar was 137.1oC The tendency of temperature rise in concrete and steel rebar changed between 100oC and 150oC The cause of decrease in temperature rise was due to the water vaporization in concrete, the lower temperature gradient of the concrete with steel and polypropylene fiber cocktails, the moisture movement toward steel rebars and the moisture clogging.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.73-82
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• 2008

Dental caries is an infectious disease caused by mutans streptococci, and is a primary etiologic agent of dental caries in humans. The molecular pathogenesis of mutans streptococcal-associated dental caries occurs in three phases. Firstly, S. mutans attaches to tooth surface via a cell surface adhesion termed antigen I/II. In the second phase, the glucosyltransferase(GTFs) synthesize polymers like glucans in the presence of sucrose. In the third phase, the multivalent glucans interacts with glucan binding proteins (GBPs) and they make dental plaque and accumulation of microorganisms. Many studies and clinical trials have indicated that a mucosal immune response to these antigens(Ag I/II, GTFs, GBPs) of S. mutans can influence the pathogenesis of dental caries. So these antigens can be important vaccine candidates for immunologic intervention against dental caries. In this study, we cloned the genes for GTFb, GTFc, GTFd from S. mutans GS-5 and did the nucleotide sequence analysis. And the recombinant proteins of GTFd and N-terminus of GTFd were expressed. Intact GTF which we get from this experiment can be used for antibody production specific for any GTF activity domain through animal experiment.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.610-616
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• 2011

Clubroot disease caused by Plasmodiophora brassicae, induces damage to cruciferous vegetables worldwide. For control of the disease, many CR (clubroot resistant) $F_1$ hybrid cultivars of Chinese cabbage have been bred and released in Korea. In this study, we determined the race of 10 field isolates of P. brassicae collected from ten regions in Korea using Williams' differential varieties and investigated the degree of resistance of 25 commercial CR cultivars of Chinese cabbage to the isolates. The clubroot pathogens were assigned into two (HS and YC), two (HN1 and HN2), two (DJ and SS) and four (GS, GN, JS, and PC) isolates for race 2, race 4, race 5, race 9, respectively. All CR cultivars showed similar response, resistant or susceptible, to each isolate and the P. brassicae isolates were divided into two groups. Among them, the DJ, GS, GN, HS, and JS isolates could not infect the CR cultivars. In contrast, the SS, HN1, HN2, PC, and YC isolates caused severe clubroot disease on the CR cultivars like susceptible cultivars. Even though they belong to the same race, the CR cultivars showed a different response to the pathogens. The results suggest that the breakdown of CR in Chinese cabbage has already occurred in cultivation areas of Korea and resistance source introduced in CR cultivars may be very limited. In addition, it is likely that resistance genes of Williams' differential varieties to P. brassicae are different from the gene of CR cultivars of Chinese cabbage used in the study.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.5-13
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• 2014

In this study, exfoliated vermiculite (EV) coated with glycerol was tested for its abiility to remove phosphorus in aqueous solution. The glycerol modified vermiculite (GS) was prepared with EV/glycerol ratio of 1/4 where glycerol contained 4 mol% $H_2SO_4$ and heated until designated temperature. GS heated at $380^{\circ}C$ showed that the specific surface area was $53.1m^2/g$ and mass loss due to oxidation of carbon was maximum from TGA analysis. Removal of phosphorus using GS heated at $380^{\circ}C$ was well explained by Langmuir isotherm model and maximum sorption capacity of 714.3 mg/kg is comparable or greater than those of other clay orignated sorbents for phosphorus.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.123-129
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• 1996

LDD structure is widely accepted in fabricating short channel MOSFETs due to reduced short channel effect originated form lower drain edge electric field. However, modeling of the LDD device is troublesome because the analysis methods of LDD region known are either too complicated or inaccurate. To solve the problem, this paper presents a nonlinear resistance model for the LDD region based on teh fact that the electron mobility changes with positive gate bias because accumulation layer of electrons is formed at the surface of the LDD region. To prove the usefulness of the model, single source/drain and LDD nMOSFETs were fabricated with 0.35$\mu$m CMOS technolgoy. For the fabricated devices we have measured I$_{ds}$-V$_{gs}$ characteristics and compare them to the modeling resutls. First of all, we calculated channel and LDD region mobility from I$_{ds}$-V$_{gs}$ characteristics of 1050$\AA$ sidewall, 5$\mu$m channel length LDD NMOSFET. Then we MOSFET and found good agreement with experiments. Next, we use calculated channel and LDD region mobility to model I$_{ds}$-V$_{gs}$ characteristics of LDD mMOSFET with 1400 and 1750$\AA$ sidewall and 5$\mu$m channel length and obtained good agreement with experiment. The single source/drain device characteristic modeling results indicates that the cahnnel mobility obtained form our model in LDD device is accurate. In the meantime, we found that the LDD region mobility is governed by phonon and surface roughness scattering from electric field dependence of the mobility. The proposed model is useful in device and circuit simulation because it can model LDD device successfully even though it is mathematically simple.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.58-64
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• 2004

This study investigated the effects of carnitine and/or ${\gamma}$ -aminobutyric acid (GABA) supplementation on lipid profiles and some immune related nutrient in mice. Balb/c male mice were orally treated with either an AIN-76 diet (Con), a control diet plus carnitine (CS, 0.5 g/kg bw), a control diet plus GABA (GS, 0.5 g/kg bw) or a control diet plus carnitine plus GABA (CGS, 0.25 g/kg bw, respectively) for 6 weeks. There were no significant differences in feed consumption, energy intake, body weight gain or feed efficiency ratio among the groups during the experimental period. However, abdominal fat deposits were smaller in CS, GS and CGS groups compared with the Con group. Serum and liver triglycerides also were lower in CS, GS and CGS and serum total cholesterol was significantly lower in the CGS group compared with the Con group. Serum LDL cholesterol was lower in the CGS group and liver HDL cholesterol was significantly higher in the CS group compared with Con group. In serum, stearic acid and selecholeic acid were lower, but arachidic acid was higher in the CS group. Liver stearic acid was higher but oleic acid lower in CGS group compared with Con group. In carnitine supplemented groups, serum and liver nonesterified carnitine (NEC), acidsoluble acylcarnitine (ASAC), total carnitine (TCNE) concentrations were higher in only the CS group, not CGS group. Serum vitamin A and E concentrations were not different among the groups. These results may suggest that carnitine and/or GABA supplementation improves lipid profiles in mice, but did not affect the immune-related nutrients that we measured under the experimental conditions of this study.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.384-389
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• 2021

An optimal ground station (GS) antenna pattern design method for network-based UAV command and control communication systems considering complexity and performance is presented. The GS antenna consists of multiple side sectors and one upward sector. The antenna gain for each vertical/horizontal angle of the GS antenna according to the change of antenna design parameters such as the number of sectors, horizontal and vertical beam-width, and tilt-angle is modeled, and the effect of the parameter changes on the signal-to-noise ratio (SNR) distribution in the virtual three-dimensional space is analyzed. It is observed that the tilt-angle of the side sectors has the greatest effect on the performance, and the longer the distance between GSs, the higher the maximum altitude and the smaller the number of side sectors, the tilt-angle should be lower. In addition, it is observed that the wider vertical beam-width of the side sector is advantageous in maximizing the lowest SNR, but narrow vertical beam-width is advantageous in maximizing the average SNR.

• Korean Journal of Exercise Nutrition
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• v.16 no.1
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• pp.51-59
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• 2012

The purpose of this study was to examine the effects of endurance training and prolonged L-arginine supplementation on blood glucose, blood insulin, muscle glycogen, muscle glycogen synthase (GS), muscle nitric oxide (NO), muscle nitric oxide synthase (NOS), endurance performance. We equally divided 36 Sprague-Dawley mice to be distributed into control group, L-NMMA treated group and L-arginine treated group. The L-arginine treated group and L-NMMA treated group consumed 10 mg/kg/day of L-arginine and 5 mg/kg/day of L-NMMA for 6 weeks period. Mice of control group, L-arginine treated group, and L-NMMA treated groups performed swimming exercise training for 60 min once a day, 5 days per week for 6 weeks. Blood glucose had tendency to increase in L-arginine treated group than the control group, and insulin significantly increased in L-arginine treated group than the control group. L-arginine treated group showed significant increase in glycogen, GS, NO and NOS in the gastrocnemius muscle and soleus muscle compared to the control group. Whereas L-NMMA treated group showed the lowest glycogen, GS, NO and NOS in the gastrocnemius muscle and soleus muscle compared to control group and L-arginine treated group. Exhaustive swimming time had tendency to increase in L-arginine treated group compared to the value for control group. These reults indicate that endurance training and prolonged L-arginine supplementation appear to be effective in exhancing nitric oxide production, glycogen concentration and endurance performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.48 no.1
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• pp.19-24
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• 2024

For over five millennia, humans have benefited from the valuable byproducts of Bombyx mori silkworms nourished on mulberry leaves and a multitude of potential applications remains available due to the diverse array of silkworm varieties. In this work, we discuss the utilization of Daehwangjam (DHJ), golden silk (GS), and Juhwangjam (JHJ), distinctive colored silks found in Korea, as chemosensors. These novel silks emit fluorescence under external stimuli and show a diminishing fluorescence intensity when exposed to HCl vapor. The considerable surface-to-volume ratio of these cocoons allows for the identification of 5 ppm, 300 ppm, and 3000 ppm HCl vapors through decreased fluorescence intensity. The results show the suitability of natural DHJ, GS, and JHJ for applications in biosensing applications.

• Information and Communications Magazine
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• v.5 no.3
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• pp.339-347
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• 1988

PC system의 보급이 확대됨에 따라 근거리 지역 내에 분산되어 있는 PC들을 상호 연결시켜 PC의 분산처리 능력을 최대한 이용하면서 주변장치, 정보 등의 자원을 공유함으로써 경비의 절감과 고속의 통신을 보장하여 전체 System의 효율을 증가시키는 PC LAN(Local Area Network)이 필요하게 되었다. 이에 PC LAN 구성에 필요한 여러 통신방식의 기술과 통신의 기본이 되는 Protocol 및 Network Operating System에 대새 논하고 실제 국내에서 개발되어 사용 중인 GS-TRN을 소개한다.