• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.92-96
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• 2003

본 논문에서는 IMT-2000 기지국용 30 W 전력증폭기를 구현하고 전파흡수체를 사용하여 발진과 상호간섭에 의한 신호의 왜곡을 제거하므로써 이득평탄도 및 상호 변조 왜곡을 개선하였다. 사용된 전파흡수체의 흡수능은 3.6 ㎓ 대역에서 -10 ㏈ 이하, 2.3 ㎓ 대역에서 -4 ㏈ 이하가 측정되었다. 기존의 전력증폭기의 특성을 측정한 결과 이득은 57.37 ㏈(측정시 40 ㏈ 감쇠기 부가) 이상, 이득평탄도는$\pm$0.33 ㏈ 였으며, 출력의 세기가 33.3 W 일 때 IMD 특성은 27 ㏈c 로 나타났다. 한편 전력증폭기의 최종단인 고출력 전력결합기 부분에 전파흡수체를 부착한 후의 이득은 약 58.43 ㏈(측정시 40 ㏈ 감쇠기 부가) 이상, 이득평탄도는 $\pm$0.0935 ㏈ 가 나타났으며, 출력이 33.3 W 일때 3차 IMD 성분은 약 29 ㏈c 였다. 측정 결과 전파흡수체를 사용하였을 경우와 사용하지 않았을 경우 이득은 1 ㏈, 이득평탄도는 0.3 ㏈, IMD 특성은 1.77 ㏈c 가 각각 개선됨을 확인하였다.

• 센서학회지
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• 제15권4호
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• pp.237-244
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• 2006

Atomic force microscope (AFM) has become a common tool for the structural and physical studies of biological macromolecules, mainly because it provides the ability to perform experiments with samples in a buffer solution. In this study, structure of proteins and nucleic acids has been studied in their physiological environment that allows native intermolecular complexes to be formed. Cr and Au were deposited on p-Si (100) substrate by thermal evaporation method in sequence with the thickness of $200{\AA}$ and $500{\AA}$, respectively, since Au is adequate for immobilizing biomolecules by forming a self-assembled monolayer (SAM) with semiconductor-based biosensors. The SAM, streptavidin and biotin interacted each other with their specific binding energy and their adsorption was analyzed using the Bio-AFM both in a solution and under air environment. A silicon nitride tip was used as a contact tip of Bio-AFM measurement in a solution and an antimony doped silicon tip as a tapping tip under air environment. Actual morphology could also be obtained by 3-dimensional AFM images. The length and agglomerate size of biomolecules was measured in stages. Furthermore, $R_{a}$ (average of surface roughness) and $R_{ms}$ (mean square of surface roughness) and surface density for the adsorbed surface were also calculated from the AFM image.

• 한국농공학회논문집
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• 제53권2호
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• pp.75-82
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• 2011

This study was performed to evaluate the water purification properties of bio-composites planting blocks using oyster shell and effective microorganism that have high absorption ability of heavy metals and organics to develop environmentally friendly river embankment technique contained various factors such as oyster shells, effective microorganism, porous concrete and planting embankment block. To maximize greening effect, the seeds were arbitrarily sown. In addition, in order to analyze the effect of water quality purification after the planting, the samples were collected from each designated zone 1, 7 and 30 days after steeping in water. Then, the samples were analyzed in terms of seven test items such as SS, BOD, COD, T-N, T-P, pH, etc. on the basis of the test method for water pollution. The following conclusions were reached from the test result. As a result of analysis for water quality purification for the concrete block containing the effective microorganism, it was found that the values for SS, BOD, T-N and T-P for the sample taken after 30 days were lower than the initial values, which indicated that the water purification effect had been created. The result of the water quality purification analysis for the concrete block containing oyster shell showed that the values for SS, BOD, COD and T-P for the sample taken after 30 days were lower than the initial values which also indicated that it had been effective in water quality purification.

• 폴리머
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• 제37권6호
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• pp.736-743
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• 2013

공액구조 고분자의 밴드갭을 줄이기 위하여 청색의 디페닐렌비닐렌을 치환기를 갖는 카바졸 단량체와 용해도 향상을 위해 옥틸기를 도입한 카바졸 공단량체를 합성하여 신규 공중합체를 제조하였다. Suzuki 커플링 중합으로 공중합체를 제조하고, 공중합체의 열적, 분광학적, 전기광학적 특성을 조사하여 고분자 유기발광 다이오드(PLED)의 발광층에의 사용가능성을 조사하였다. 용액상태에서 공중합체의 UV 최대 흡수 파장은 333~340 nm, PL 최대방출 파장은 409~464 nm를 보였으며, 상대양자효율은 최대 25.8%의 값을 보였다. 열중량분석 결과 $350^{\circ}C$까지 열안정성을 보이고, 필름형성이 용이하였으며, 공중합체를 발광층으로 사용한 PLED 소자에서 4.0 V에서 청색광을 나타내었다.

• 한국식품영양학회지
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• 제20권3호
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• pp.304-310
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• 2007

This study was carried out to evaluate the phsicochemical, rheological and sensory characteristics of the restructured pork jerky with the addition of sliced cheese(4, 8 and 12%). The TC-1, TC-2 and TC-3 samples had lower moisture contents than the control, Crude protein and fat contents were significantly difference among all treatment (p<0.05). The crude ash and salinity values of TC-1, TC-2 and TC-3 were higher than the control. With the addition of sliced cheese(l2%), the manufacturing yield and water absorption ability were high among all the different treatments, but the control showed significantly higher values than TC-1, TC-2 and TC-3. The pH ranged from 5.62-6.01 in all treatments and the TC-3 sample had the highest pH, The water activity range was 0.70 - 0.74, and the various treatments had slightly higher than the control. The hardness of the TC-3( J 2%) treatment was the lowest among all the treatment. The strength values increased according to increases in sliced cheese, but there were no significant differences(p>0.05). The sensory evaluation for color and flavor received the highest scores in working males 6.96(TC-2) and student males 7.50(TC-2), respectively. The texture scores ranged from 7.07-7.63 and were the highest of all sensory evaluation factors, For overall acceptance the highest scores were received from student males(TC-3), student females(TC-2), working males(TC-2) and working females(TC-l), respectively.

• 한국축산식품학회지
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• 제30권3호
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• pp.443-448
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• 2010

유제품, 김치 및 신생아 분변 등에서 유산균을 분리하여 우유 casein을 분해시켜 배양상등액에 존재하는 serine의 함량을 측정함으로써 간접적으로 CPP 생산을 평가하였다. CPP 생산 능력은 OPA방법으로 측정했을 때 E. faecalis A-2 균주가 1.244 mg/mL로 가장 많은 peptide를 생산 하였다. 본 실험에 사용된 유산균의 경우, 세포내 효소와 세포외 효소로 각각 나누어 proteolytic 활성을 평가한 결과 세포내 효소에 의한 proteolytic 활성은 E. faecalis A-6 균주가 가장 높은 것으로 나타났으며, 세포외 효소에 의한 proteolytic 활성은 L. plantarum A-14 균주에서 가장 높게 나타났다. 가용성 칼슘함량은 Leuconostoc mesenteroides A-1(11 mg/dL), E. durans A-16(10.481 mg/dL), 그리고 L. planatarum A-3(10.356 mg/dL) 균주의 경우에는 대조구보다 높은 유리 칼슘함량을 나타내었다. 따라서 이러한 유산균을 이용한다면 소장 내에서 칼슘 흡수를 극대화시킬수 있는 장점이 있어 이들 유산균을 이용한 고칼슘 제품 개발이 가능할 것이다.

• 폴리머
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• 제32권5호
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• pp.415-420
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• 2008

면역 거부반응이 없는 돼지 소장점막하조직(small intestinal submucosa, SIS)과 천연보습제인 히알루론산(hyaluronic acid, HA)은 생체재료로 널리 사용되고 있다. 본 연구에서는 이를 이용하여 스폰지를 제조하고 이들의 특성을 분석하였다. SIS-HA 스폰지는 완성된 SIS 스폰지에 1w%의 HA겔을 첨가하여 동결건조법으로 제조하고 100mM의 가교제를 통해 가교하여 이를 전자주사현미경, 적외선분광기, 물흡수성 실험을 하였다. 초기 세포부착률을 확인하고자 NIH/3T3를 분주하여 MTT 분석법을 수행하였다. FT-IR 분석을 통해 C-O관능기가 관찰되어 SIS-HA 스폰지 내부의 HA가 빠져나가지 않고 고르게 분포되어 있음을 확인하였고, MTT분석을 통하여 제조된 스폰지에서의 높은 세포생존율을 확인하였다. 즉, 본 연구에서 제조한 SIS-HA 스폰지는 SIS와 HA 각각의 특성을 모두 내재하고 있어 조직공학적 담체로 적합할 것이다.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1311-1322
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• 2021

Microbially induced calcium carbonate precipitation (MICP) has recently become an intelligent and environmentally friendly method for repairing cracks in concrete. To improve on this ability of microbial materials concrete repair, we applied random mutagenesis and optimization of mineralization conditions to improve the quantity and crystal form of microbially precipitated calcium carbonate. Sporosarcina pasteurii ATCC 11859 was used as the starting strain to obtain the mutant with high urease activity by atmospheric and room temperature plasma (ARTP) mutagenesis. Next, we investigated the optimal biomineralization conditions and precipitation crystal form using Plackett-Burman experimental design and response surface methodology (RSM). Biomineralization with 0.73 mol/l calcium chloride, 45 g/l urea, reaction temperature of 45℃, and reaction time of 22 h, significantly increased the amount of precipitated calcium carbonate, which was deposited in the form of calcite crystals. Finally, the repair of concrete using the optimized biomineralization process was evaluated. A comparison of water absorption and adhesion of concrete specimens before and after repairs showed that concrete cracks and surface defects could be efficiently repaired. This study provides a new method to engineer biocementing material for concrete repair.

• 한국환경과학회지
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• 제27권11호
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• pp.967-974
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• 2018

In this study, we evaluated the photocatalytic oxidation efficiency of aromatic volatile hydrocarbons by using $WO_3$-doped $TiO_2$ nanotubes (WTNTs) under visible-light irradiation. One-dimensional WTNTs were synthesized by ultrasonic-assisted hydrothermal method and impregnation. XRD analysis revealed successful incorporation of $WO_3$ into $TiO_2$ nanotube (TNT) structures. UV-Vis spectra exhibited that the synthesized WTNT samples can be activated under visible light irradiation. FE-SEM and TEM images showed the one-dimensional structure of the prepared TNTs and WTNTs. The photocatalytic oxidation efficiencies of toluene, ethylbenzene, and o-xylene were higher using WTNT samples than undoped TNT. These results were explained based on the charge separation ability, adsorption capability, and light absorption of the sample photocatalysts. Among the different light sources, light-emitting-diodes (LEDs) are more highly energy-efficient than 8-W daylight used for the photocatalytic oxidation of toluene, ethylbenzene, and o-xylene, though the photocatalytic oxidation efficiency is higher for 8-W daylight.

• 한국운동역학회지
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• 제29권2호
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• pp.53-60
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• 2019

Objective: The purpose of this study was to investigate the differences of smoothness and coordination of the fingers and upper extremities between skilled and non-skilled players during receiving the basketball. Method: Ten male recreational basketball players (age: $23.2{\pm}2.7yrs.$, career: $8.6{\pm}1.6yrs.$, height: $177.3{\pm}6.0$, weight: $72.9{\pm}8.5kg$) careering over five years and ten non-skilled males (age: $27.3{\pm}1.5yrs.$, height: $173.7{\pm}5.6$, weight: $73.2{\pm}12.6kg$) were participated in this study. Then, participants were asked to perform basketball receiving movement for ten times. The receiving movements were recorded by eight infrared cameras (Oqus 300, Qualisys, Sweden). The collected rad data were calculated to duration of basketball receiving, Jerk-Cost, CRP and CRP variability. Results: The CRP of MCP-Wr, Wr-El in skilled group were greater than non-skilled group (p<.05). The CRP variability of El-Sh in non-skilled group was greater than skilled group (p<.05). Conclusion: These results suggest that skilled players perform more effective movement for impact absorption from the basketball. Moreover, the skilled players have consistent movement patterns during basketball performance. Lastly, it is important to train finger sensation and cognitive ability of thrown basketball from the passer.