• 한국미생물·생명공학회지
• /
• 제46권4호
• /
• pp.403-415
• /
• 2018

The aims of this novel work were to determine the microbial strains and exopolysaccharide (EPS) producers in water kefir from Nakhon Ratchasima Province, Thailand. Thirty-three microbial strains were identified using 16S rRNA gene analysis consisting of 18 bacterial strains, as 9 strains of acetic acid bacteria (AAB), 9 strains of lactic acid bacteria (LAB), and 15 yeast strains. All bacteria were able to produce EPS with a diverse appearance on agar media containing different sugars at a concentration of 8%. Culture supernatants from AAB and LAB showed 31-64% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity with the highest antioxidant activity of 64% from Acetobacter pasteurianus WS3 and WS6. Crude EPS from A. pasteurianus WS3 displayed the highest ferric reducing antioxidant power at 280 mM $FeSO_4/g$ EPS, greatest anti-tyrosinase activity at 20.35%, and highest EPS production of 1,505 mg EPS/L from 8% sucrose. These microbes offer beneficial health implications and their EPSs can be used as food additives and cosmetic ingredients.

• 한국전자파학회논문지
• /
• 제16권7호
• /
• pp.753-759
• /
• 2005

본 논문에서는 표면 MEMS 기술을 이용하여 제작된 $180^{\circ}$ 하이브리드 결합기가 집적된 60 GHz 대역의 단일평형 혼합기를 설계$\cdot$제작하였다. 혼합기에 사용된 $180^{\circ}$ 하이브리드 결합기는 substrate에 의한 dielectric loss를 최소화하기 위하여 polyimide dielectric을 지지대로 사용하여 신호선이 공기 중에 떠 있는 형태의 마이크로스트립 라인을 이용하여 설계하였으며, 이때 지지대의 높이는 $10{\mu}m$이고 면적은 $20{\mu}m{\times}20{\mu}m$을 사용하였다. 제작된 혼합기 의 측정 결과, LO 주파수가 58 GHz에서 LO power가 7.2 dBm 57 GHz에서 RF power가 -15 dBm 일 때, 15.5 dB의 변환 손실과 -40 dB의 RF-LO isolation 특성을 얻었다. 본 논문에서 제안된 혼합기는 RF MEMS 수동 소자를 MMIC와 집적화 함으로써 칩 성능의 감소 없이 크기를 줄일 수 있다는 장점을 가지고 있다.

• 대한전자공학회논문지TC
• /
• 제41권8호
• /
• pp.105-111
• /
• 2004

본 논문에서는 밀리미터파 대역에서 고이득과 광대역 특성을 갖는 MHEMT(Metamorphic High Electron Mobility Transistor) cascode 증폭기를 설계 및 제작하였다. Cascode 증폭기 제작을 위해 0.1 ㎛ InGaAs/InAlAs/GaAs MHEMT를 설계ㆍ제작하였다. 제작된 MHEMT는 드레인 전류 밀도 640 mA/mm, 최대 전달컨덕턴스(gm)는 653 mS/mm를 얻었으며, 주파수 특성으로 f/sub T/는 173 GHz, f/sub max/는 271 GHz의 우수한 특성을 나타내었다. Cascode 증폭기는 CPW 전송선로를 이용하여 광대역 특성을 얻을 수 있도록 정합회로를 설계하였으며, 1단과 2단 증폭기의 2가지 종류로 회로를 설계하였다. 설계된 증폭기는 본 연구에서 개발된 MHEMT MIMIC 공정을 이용해 제작되었다. 제작된 cascode 증폭기의 측정결과, 1단 증폭기는 3 dB 대역폭이 31.3∼68.3 GHz로 37 GHz의 넓은 대역 특성을 얻었으며, 대역내에서 평균 9.7 dB 및 40 GHz에서 최대 11.3 dB의 S21 이득 특성을 나타내었다. Cascode 2단 증폭기는, 3 dB 대역폭이 32.5∼62.0 GHz로 29.5 GHz의 대역폭과 대역내에서 평균 20.4 dB 및 36.5 GHz에서 최대 22.3 dB의 높은 이득 특성을 얻었다.

• 대한전자공학회논문지SD
• /
• 제42권3호
• /
• pp.1-8
• /
• 2005

본 논문에서는 $0.1\;{\mu}m$ 이하의 게이트 길이를 갖는 MHEMT의 DC 및 RF 특성을 상용 시뮬레이터인 ISE-TCAD tool을 이용하여 결과를 고찰하였다. 이후 MHEMT의 게이트 길이와, 소스-드레인 간격 및 채널 두께를 변화시켜 가면서 소자의 수평, 수직 Scaling효과가 소자 특성에 미치는 영향을 비교하였으며, 게이트 길이 $(L_g)$가 $0.1\;{\mu}m$ 이하로 감소함에 따라 $g_{m,max}$가 같이 감소하는 현상에 대해서 논의해 보았다. 또한 이 현상을 가지고 소자의 횡적, 종적 파라미터의 scaling 효과에 대한 모델을 제시 했다.

• 대한전자공학회논문지SD
• /
• 제44권4호
• /
• pp.80-85
• /
• 2007

Passivation 기술은 소자를 외부 환경의 영향으로부터 보호할 수 있고, 소자 성능의 감소를 예방할 수 있기 때문에 능동 소자 제작에 있어서 매우 중요하다. 본 논문에서 passivation 물질로 낮은 유전 상수를 갖는 benzocyclobutene (BCB)과 전통적인 passivation 물질인 Si3N4를 이용하여 GaAs를 기반으로 하는 $0.1{\mu}m\;{\Gamma}$-gate InAlAs/InGaAs metamorphic high electron mobility transistors (MHEMTs)를 제작하였다. 제작된 MHEMT의 특성은 passivation 전과 후로 구분하여 비교하였다. Passivation후 BCB와 Si3N4를 이용한 경우 모두에서 passivation 이전에 비해 저하된 DC 및 RF 특성을 나타내었으나, BCB를 이용하여 passivation을 한 소자들이 전통적인 passivation 물질인 Si3N4를 이용한 소자들에 비해서 상대적으로 낮은 특성 저하를 DC와 RF에서 함께 나타내었다.

• 대한전자공학회논문지TC
• /
• 제43권10호
• /
• pp.90-97
• /
• 2006

본 논문에서는 cascode 구조에 shunt peaking 기술을 접목시킨 밀리미터파 광대역 amplifier를 설계 및 제작하였다. 밀리미터파 광대역 cascode amplifier의 설계 및 제작을 위해서 $0.1{\mu}m\;{\Gamma}-gate$ GaAs PHEMT와 CPW 및 passive library를 개발하였다. 제작된 PHEMT는 최대 전달 컨덕턴스는 346.3 mS/mm, 전류이득 차단 주파수 ($f_T$)는 113 GHz, 그리고 최대공진 주파수($f_{max}$)는 180 GHz의 특성을 갖고 있다. 설계된 cascode amplifier는 회로의 발진을 막기 위해서 저항과 캐패시터를 common-rate 소자의 드레인에 병렬로 연결하였다. 대역폭의 확장 및 gain의 평탄화를 위해 바이어스 단들에 short stub 및 common-source 소자와 common-gate 소자 사이에 보상 전송선로를 삽입하고 최적화하였으며, 입출력 단은 광대역 특성을 갖는 정합회로로 설계하였다. 제작된 cascode amplifier의 측정결과, cascode 구조에 shunt peaking 기술을 접목시킴으로써 대역폭을 확장 및 gain을 평탄화 시킬 수 있다는 것을 확인하였다. 3 dB 대역폭은 34.5 GHz ($19{\sim}53.5GHz$)로 광대역 특성을 얻었으며, 3 dB대역 내에서 평균 6.5 dB의 $S_{21}$ 이득 특성을 나타내었다.

• 경영과정보연구
• /
• 제17권
• /
• pp.135-160
• /
• 2005

In the 1990s, university environment is changing rapidly(especially, difficulty of student registration which are originated student's decrease and various deregulation) and university get ready for the new ways of management culture. This new ways are management innovation strategies. The purpose of this study is to suggest the direction of effective innovation(to search application possibility of management innovation strategy), solving the problems occurred by the enlargement and change in the environments of universities. From early in the 1990s, korean corporations perform actively many management innovation strategy including benchmarking, restructuring, downsizing, zero-based budgeting, BPR, learn organization and total quality management. But korean most universities performed hardware management innovation strategies such as corporate portfolio restructuring(including outsourcing, M&A, MBO etc.) and organization restructuring. Therefore korean universities have got to concerns about more software management innovation strategy such as total quality management and learn organization. Also we have seen another problems such as that universities try to merely duplicate certain management innovation strategies which are used by another university. rather than to make various effort to adequate their own organizations. In conclusion, korean universities are to play an important roles in the development of knowledge society. The management innovation and individual competence development in the university are required to overcome crisis of university.

• 한국운동역학회지
• /
• 제30권4호
• /
• pp.301-309
• /
• 2020

Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

• Animal Bioscience
• /
• 제34권7호
• /
• pp.1210-1220
• /
• 2021

Objective: Unlike mammals, goose fatty liver shows a strong tolerance to fatty acids without obvious injury. Stearyl-coenzyme A desaturase 1 (SCD1) serves crucial role in desaturation of saturated fatty acids (SAFs), but its role in the SAFs tolerance of goose hepatocytes has not been reported. This study was conducted to explore the role of SCD1 in regulating palmitic acid (PA) tolerance of goose primary hepatocytes. Methods: 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide was examined to reflect the effect of PA on hepatocytes viability, and quantitative polymerase chain reaction was used to detect the mRNA levels of several genes related to endoplasmic reticulum (ER) stress, inflammation, and apoptosis, and the role of SCD1 in PA tolerance of goose hepatocytes was explored using RNA interfere. Results: Our results indicated that goose hepatocytes exhibited a higher tolerant capacity to PA than human hepatic cell line (LO2 cells). In goose primary hepatocytes, the mRNA levels of fatty acid desaturation-related genes (SCD1 and fatty acid desaturase 2) and fatty acid elongate enzyme-related gene (elongase of very long chain fatty acids 6) were significantly upregulated with 0.6 mM PA treatment. However, in LO2 cells, expression of ER stress-related genes (x box-binding protein, binding immunoglobulin protein, and activating transcription factor 6), inflammatory response-related genes (interleukin-6 [IL-6], interleukin-1β [IL-1β], and interferon-γ) and apoptosis-related genes (bcl-2-associated X protein, b-cell lymphoma 2, Caspase-3, and Caspase-9) was significantly enhanced with 0.6 mM PA treatment. Additionally, small interfering RNA (siRNA) mediated downregulation of SCD1 significantly reduced the PA tolerance of goose primary hepatocytes under the treatment of 0.6 mM PA; meanwhile, the mRNA levels of inflammatory-related genes (IL-6 and IL-1β) and several key genes involved in the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), forkhead box O1 (FoxO1), mammalian target of rapamycin and AMPK pathways (AKT1, AKT2, FoxO1, and sirtuin 1), as well as the protein expression of cytochrome C and the apoptosis rate were upregulated. Conclusion: In conclusion, our data suggested that SCD1 was involved in enhancing the PA tolerance of goose primary hepatocytes by regulating inflammation- and apoptosis-related genes expression.

• Asian Journal of Innovation and Policy
• /
• 제4권2호
• /
• pp.217-241
• /
• 2015

This paper, based on two engineering industry SME case studies, traces the origin and process of technological innovations enabling the development and introduction of new products leading to market expansion and enterprise growth. The study throws light on how entrepreneurs played a decisive role in recognizing market opportunities, building up crucial in-house technological capability, supplementing it with appropriate external assistance, to carry out technological innovations. A constant interaction with its customers is in-built into the system. As a result, the SMEs could achieve successful product innovations leading to their gradual growth, over time. Finally, based on the observations and inferences derived out of the two cases, a theoretical construct of the growth of innovation in SMEs is postulated. This is done linking the three stages of their development: (i) start-up and stabilizing, (ii) building up technological capability and implementing innovations; and (iii) opening up of new markets resulting in firm growth.