• 한국식품영양학회지
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• 제17권2호
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• pp.220-228
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• 2004

Tenax-TA와 동적 headspace 향 포집방법을 이용하여 볶음들기름의 향기성분을 농축하였다. 이때 반응표면분석법을 이용하여 Tenax-TA에 결합한 향기성분의 탈착에 의한 손실을 최소화하고 휘발성이 낮은 화합물의 포집 효율을 극대화시키는 최적조건을 결정하였다. 독립변수로 향 포집 온도와 시간 및 시료량을 설정하였고 총 peak 면적, 탈착율, 휘발성이 가장 낮은 화합물인 perilla ketone의 면적을 종속변수로 하였다. 등고선 그림을 겹친 결과 0.6 g의 볶음들기름을 48$^{\circ}C$에서 12분 동안 포집시키는 것이 최적조건이었으며 Tenax-TA에서 탈착되는 주요한 휘발성 화합물은 2-propanone, 2-butanone, acetic acid 및 2-methyl propanal이었다.

• Journal of Microbiology and Biotechnology
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• 제23권9호
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• pp.1293-1303
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• 2013

Antibiotic resistance of soilborne Acinetobacter species has been poorly explored. In this study, norfloxacin resistance of a soil bacterium, Acinetobacter oleivorans DR1, was investigated. The frequencies of mutant appearance of all tested non-pathogenic Acinetobacter strains were lower than those of pathogenic strains under minimum inhibitory concentration (MIC). When the quinolone-resistance-determining region of the gyrA gene was examined, only one mutant (His78Asn) out of 10 resistant variants had a mutation. Whole transcriptome analysis using a RNA-Seq demonstrated that genes involved in SOS response and DNA repair were significantly up-regulated by norfloxacin. Determining the MICs of survival cells after norfloxacin treatment confirmed some of those cells were indeed persister cells. Ten colonies, randomly selected from among those that survived in the presence of norfloxacin, did not exhibit increased MIC. Thus, both the low mutation frequency of the target gene and SOS response under norfloxacin suggested that persister formation might contribute to the resistance of DR1 against norfloxacin. The persister frequency increased without a change in MIC when stationary phase cells, low growth rates conditions, and growth-deficient dnaJ mutant were used. Taken together, our comprehensive approach, which included mutational analysis of the target gene, persister formation assays, and RNA sequencing, indicated that DR1 survival when exposed to norfloxacin is related not only to target gene mutation but also to persister formation, possibly through up-regulation of the SOS response and DNA repair genes.

• 센서학회지
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• 제20권1호
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• pp.1-7
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• 2011

Undoped and Sb-doped $SnO_2$ nanofibers were prepared by electrospinning and their responses to $H_2$, CO, $CH_4$, $C_3H_8$, and $C_2H_5OH$ were measured. In the undoped $SnO_2$ nanofibers, the gas response ($R_a/R_g$, $R_a$: resistance in air, $R_g$: resistance in gas) to 100 ppm $C_2H_5OH$ was very high(33.9), while that to the other gases ranged from 1.6 to 2.2. By doping with 2.65 wt% Sb, the response to 100 ppm $C_2H_5OH$ was decreased to 4.5, whereas the response to $H_2$ was increased to 3.0. This demonstrates the possibility of detecting a high $H_2$ concentration with minimum interference from $C_2H_5OH$ and the potential to control the gas selectivity by Sb doping.

• 생명과학회지
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• 제14권4호
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• pp.589-592
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• 2004

Ceratium 적조생물을 메타놀이나 수용성 물질을 분리하거나 cell-free medium 추출물을 Cochlodinium polykrikoides 성장에 미치는 영향을 조사했다. cell-free medium을 25% 이상 첨가한 시험구에서 가장 우수한 C. polykrikoides 성장을 가져왔다. 그러나 메타놀이나 수용성으로 처리한 추출물에서는 고농도로 배지에 첨가시켜도 C. polykrikoides 성장에는 큰 영향이 없었다. 특히 cell-free medium은 Gyredinium impudicum이나 Chaetoceros 종에서도 C. polykrikoides와 비슷한 양상을 보였으나, Alxendrium 적조생물에 대해서는 현저히 성장을 저해시키는 결과를 나타내었고, Prorocentrium minimum에서도 성장을 촉진시키지는 못했다. 이러한 결과로 보와서 Ceratium 추출물은 C. polykrikoides성장을 촉진시킬 수 있는 주요한 역할을 하는 것으로 보여서 두 적조생물이 공존하게 되면 상호간에 영향을 미칠 수 있을 것으로 판단된다.

• 센서학회지
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• 제17권3호
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• pp.183-187
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• 2008

A sub-ppm level MEMS gas sensor that can be used for the detection of formaldehyde (HCHO) is presented. It is realized by using a zinc oxide (ZnO) thin-film material with a Ni-seed layer as a sensing material and by bulk micromachining technology. To enhance sensitivity of the MEMS gas sensor with Ni-seed layer was embedded with ZnO sensing material and sensing electrodes. As experimental results, the changed sensor resistance ratio for HCHO gas was 9.65 % for 10 ppb, 18.06 % for 100 ppb, and 35.7 % for 1 ppm, respectively. In addition, the minimum detection level of the fabricated MEMS gas sensor was 10 ppb for the HCHO gas. And the measured output voltage was about 0.94 V for 10 ppb HCHO gas concentration. The noise level of the fabricated MEMS gas sensor was about 50 mV. The response and recovery times were 3 and 5 min, respectively. The consumption power of the Pt micro-heater under sensor testing was 184 mW and its operating temperature was $400^{\circ}C$.

• 대한약침학회지
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• 제12권3호
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• pp.41-47
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• 2009

Objectives : This experimental study was performed to investigate the efficacy of Fel Ursi, Bovis Calculus & Moschus pharmacopuncture solution manufactured with freezing dryness method to use eye drop. Methods : After administering Fel Ursi, Bovis Calculus & Moschus pharmacopuncture solution on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) which cause Keratitis, MIC(Minimum Inhibition Concentration) and the size of inhibition zone were measured. Anti-bacterial potency was also measured using the size of inhibition zone. Results : There was no response to MIC on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) after Fel Ursi, Bovis Calculus & Moschus pharmacopuncture solution was medicated. Conclusions : The present study suggests that Fel Ursi, Bovis Calculus & Moschus pharmacopuncture solution dosen't have anti-bacterial effects on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans) which cause Keratitis. These study result recommends that more research on other herbal medicines of eye drop for Keratitis are required.

• Structural Monitoring and Maintenance
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• 제3권3호
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• pp.195-214
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• 2016

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

• 대한약침학회지
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• 제13권2호
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• pp.101-110
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• 2010

Objectives : This experimental study was performed to investigate the effect of Fel Ursi & Bovis Calculus pharmacopuncture solution(FUBCPS) manufactured by using alcohol/water extraction method for identify ing the use of it as eyedrops. Methods: FUBCPS was manufactured by using alcohol/water extraction method. Measure the size of inhibition zone and MIC(Minimum Inhibition Concentration) after administering FUBCPS on bacterial species. Staphylococcus aureus. Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum and Candida albicans, which cause keratitis. Administering cravit(Levonoxacin medicine) on bacterial species also performed to compare the anti-bacterial potency of this material, measured by using the size of inhibition zone Results : After administering FUBCPS on bacterial species(Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Aspergillus niger, Fusarium oxysporum, Candida albicans). there was no response to MIC and there was no anti -bacterial potency also. Conclusions : This study suggests that FUBCPS dose not have anti-bacterial effects on bacterial species which cause Keratitis. These study result recommends that we need to research more on herbal medicines of eye drop which have anti-bacterial effects on keratitis

• Advances in nano research
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• 제12권4호
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• pp.387-403
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• 2022

Silica nanoparticles, which have a broad range of sizes and specific surface features, have been used in many industrial applications. This study was conducted to synthesize monodispersed silica nanoparticles directly from tetraethyl orthosilicate (TEOS) with an alkaline catalyst (NH₃) based on the sol-gel process and the Stöber method. A central composite design (CCD) is used to build a second-order (quadratic) model for the response variables without requiring a complete three-level factorial experiment. The process was then optimized to achieve the minimum particle size with the lowest concentration of TEOS. Dynamic light scattering and scanning electron microscopy were used to analyze the size, dispersity, and morphology of the synthesized nanoparticles. After optimization, a confirmation test was carried out to evaluate the confidence level of the software prediction. The results revealed that the predicted optimization is consistent with experimental procedures, and the model is significant at the 95% confidence level.

• 산업식품공학
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• 제13권1호
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• pp.8-15
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• 2009

본 연구에서는 미강과 배아로부터의 ${\beta}$-glucan 추출 공정 최적화를 위해 반응표면 분석법으로 모니터링 하였다. 중 심합성계획법에 따라 추출 온도($X_1$), 추출 시간($X_2$), 추출온도($X_3$)를 요인변수(Xn)로 하고 미강 추출물의 전자공여 능($Y_1$), 배아 추출물의 전자공여능($Y_2$), 미강 추출물의 total phenolics($Y_3$), 배아 추출물의 total phenolics($Y_4$), 미강 추출물의 ${\beta}$-glucan 함량($Y_5$), 배아 추출물의 ${\beta}$-glucan 함량 ($Y_6$)을 종속변수로 하여 시행하였다. 실험 결과 미강 추출물의 전자공여능도는 추출 온도에 영향을 받음을 알 수 있었다. 안장점에서 추출 조건은 추출 온도는 $60.41^{\circ}C$, 추출 시간은 2.75 min, 에탄올 농도 92.60%로 예측되었으며 이 때 84.02%로 비교적 높은 항산화 활성을 보여주었다. 배아 추출물의 전자공여능도의 안장점에서 추출 조건은 추출 온도 $54.40^{\circ}C$, 추출 시간 2.23 min, 에탄올 농도 87.52%였다. 미강 추출물의 total phenolics는 추출 온도와 에탄올 농도에 영향을 크게 받은 것으로 나타났고 안장점에서 추출 조건은 추출 온도 $40.26^{\circ}C$, 추출 시간 6.69 min, 에탄올 농도 98.56%로 예측 되었고 배아 추출물의 total phenolics는 최소점에서 추출온도 $53.67^{\circ}C$, 추출 시간 9.19 min, 에탄올 농도 95.73%에서 최대값을 나타내었다. 미강 추출물의 ${\beta}$-glucan 함량은 안장점일 때 추출 조건이 추출 온도 $64.69^{\circ}C$, 추출 시간 7.70 min, 에탄올 농도 96.23%로 나타났다. 배아 추출물의 ${\beta}$-glucan 함량은 추출 시간에 영향을 크게 받았으며 최소점에서 추출 온도 $50.03^{\circ}C$, 추출 시간 2.10 min, 에탄올 농도 87.82%에서 미강 추출물에서보다 더 높은 최대값을 나타내었다.