• Proceedings of the Korean Vacuum Society Conference
• /
• 2000.02a
• /
• pp.78-78
• /
• 2000

다결정 실리콘-게르마늄 (poly-SiGe)은 태양전지 개발에 있어서 중요한 물질이다. 우리는 소량의 Ge(x=0.05)으로부터 다량의 Ge(x=0.67)을 함유한 수소화된 비정질 실리콘-게르마늄 (a-SiGe:H) 박막의 고상결정화 과정을 ESR (electron spin resonance)방법으로 조사해보았다. 먼저 PECVD 방법으로 Corning 1737 glass 위에 a-Si1-xGex:H 박막을 증착시켰다. 증착가스는 SiH4, GeH4 가스를 썼으며, 기판온도는 20$0^{\circ}C$, r.f. 전력은 3W, 증착시 가스압력은 0.6 Torr 정도이었다. 증착된 a-SiGe:H 박막은 $600^{\circ}C$ N2 분위기에서 다시 가열되어 고상결정화 되었고, 결정화 정도는 XRD (111) peak의 세기로부터 구해졌다. ESR 측정은 상온 x-band 영역에서 수행되었다. 측정된 ESR스팩트럼은 두 개의 Gaussian 함수로써 Si dangling-bond와 Ge dangling-bond 신호로 분리되었다. 가열 초기의 a-SiGe:H 박막 결함들의 스핀밀도의 증가는 수소 이탈에 기인하고, 또 고상결정화 과정에서 결정화된 정도와 Ge-db 스핀밀도의 변화는 서로 깊은 상관관계가 있음을 알 수 있었다. 특히 Ge 함유량이 큰 박막 (x=0.21, 0.67)에서 뿐만 아니라 소량의 Ge이 함유된 박막(x=0.05)에서도 Ge dangling-bond가 Si dangliong-bond 보다 고상결정화 과정에서 더 중요한 역할을 한다는 것을 알수 있었다. 또한 초기 열처리시 Si-H, Ge-H 결합에서 H의 이탈로 인하여 나타나는 Si-dangling bond, Ge-dangling bond 스핀밀도의 최대 증가 시간은 x 값에 의존하였는데 이러한 결과는 x값에 의존하는 Si-H, Ge-H 해리에너리지로 설명되어 질 수 있다. 층의 두께가 500 미만인 커패시터의 경우에 TiN과 Si3N4 의 계면에서 형성되는 슬릿형 공동(slit-like void)에 의해 커패시터의 유전특성이 파괴된다는 사실을 알게 되었으며, 이러한 슬릿형 공동은 제조 공정 중 재료에 따른 열팽창 계수와 탄성 계수 등의 차이에 의해 형성된 잔류응력 상태가 유전막을 기준으로 압축응력에서 인장 응력으로 바뀌는 분포에 기인하였다는 사실을 확인하였다.SiO2 막을 약화시켜 절연막의 두께가 두꺼워졌음에도 기존의 SiO2 절연막의 절연 파괴 전압 및 누설 전류오 비교되는 특성을 가졌다. 이중막을 구성하고 있는 안티퓨즈의 ON-저항이 단일막과 비교해 비슷한 것을 볼 수 잇는데, 그 이유는 TiO2에 포함된 Ti가 필라멘트에 포함되어 있어 필라멘트의 저항을 감소시켰기 때문으로 사료된다. 결국 이중막을 구성시 ON-저항 증가에 의한 속도 저하 요인은 없다고 할 수 있다. 5V의 절연파괴 시간을 측정한느 TDDB 테스트 결과 1.1$\times$103 year로 기대수치인 수십 년보다 높아 제안된 안티퓨즈의 신뢰성을 확보 할 수 있었다. 제안된 안티퓨즈의 이중 절연막의 두께는 250 이고 프로그래밍 전압은 9.0V이고, 약 65$\Omega$의 on 저항을 얻을수 있었다.보았다.다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적화에 의한 기능성 나노 입자 제조 기술을 확립하고 2차 오염 발생원인 유기계 항균제를 무기계 항균제로 대체할 수 있다. 이와 더불

• Journal of agriculture & life science
• /
• v.46 no.1
• /
• pp.163-176
• /
• 2012

TTo increase productivity of a strong extracellular alkaline protease (BCAP), stable strains of Bacillus clausii I-52 carrying another copy of BCAP gene in the chromosome were developed. Integrative vector, pHPS9-fuBCAP carrying BCAP promoter, ribosome binding site, signal sequence and active protease gene was constructed and transferred into B. clausii I-52, and integration of the constructed plasmid into chromosome was identified by PCR. An investigation was carried out on BCAP production by B. clausii I-52 and transformant C5 showing the highest relative activity of alkaline protease using submerged fermentation. Maximum enzyme activity was produced when cells were grown under the submerged fermentation conditions at $37^{\circ}C$ for 48 h with an aeration rate of 1 vvm and agitation rate of 650 rpm in a optimized medium (soybean meal 2%, wheat flour 1%, sodium citrate 0.5%, $K_2HPO_4$ 0.4%, $Na_2HPO_4$ 0.1%, NaCl 0.4%, $MgSO_47H_2O$ 0.01%, $FeSO_47H_2O$ 0.05%, liquid maltose 2.5%, $Na_2CO_3$ 0.6%). A protease yield of approximately 134,670U/ml was achieved using an optimized media, which show an increase of approximately 1.6-fold compared to that of non-transformant (83,960 U/ml). When the stability of transformant C5 was examined, the integrated plasmid pHPS9-fuBCAP was detected in the transformant after cultivation for 8 days, suggesting that it maintained stably in the chromosomal DNA of transformant C5.

• Food Science and Preservation
• /
• v.18 no.3
• /
• pp.319-327
• /
• 2011

This study was conducted to monitor the quality characteristics of mate (Ilex paraguarensis) ethanolic extracts via the response surface methodology. In the extraction conditions that were based on the central composite design with variations in the ethanol concentration (0-100%), extraction temperature($35-95^{\circ}C$), and the ratio of the solvent to the sample (10~30 mL/g). The extraction yield and total polyphenol content improved with the increase in the ethanol concentration than in the extraction temperature. The caffeic acid content increased with the decrease in the solvent ratio. The coefficients of determinations ($R^2$) were 0.8842 (p<0.05), 0.8729 (p<0.05), and 0.9205 (p<0.05) in terms of the electron donating ability, nitrite scavenging effect (pH 3.0), and SOD-like ability, respectively. The estimated conditions for the maximized extraction, including in terms of the yield, total polyphenol content, caffeic acid content, and electron donating ability, were a 21-48% ethanol concentration, a $76.4^{\circ}C$ extraction temperature, and 10-14mL/g solvent-to-sample ratio.

• Journal of the Korea Knowledge Information Technology Society
• /
• v.12 no.4
• /
• pp.539-550
• /
• 2017

In this paper, we designed, fabricated and tested an UHF band cylindrical dipole array antenna. In the proposed antenna, cylindrical dipoles were vertically arranged in four stages. A parallel structure feeding circuit was installed inside the cylindrical dipole and mounted so as to be broadband matching. The feeding circuit was installed at the center of the cylindrical dipole to optimize the gain flatness characteristic of the azimuth direction omnidirectional radiation pattern. Minimizing the difference between the signals branched from the feeding circuit and realizing the symmetry of the radiation pattern. The required specifications are more than 11.2% bandwidth in UHF band, above 6dBi antenna gain, standing wave ratio of 2:1 or less, less than ${\pm}1dB$ gain flatness in azimuth radiation pattern, more than 13 degrees in elevation radiation pattern of 3dB beamwidth. We confirmed the possibility of implementation through M&S and verified the result of M&S through production and testing. The test results are 11.2% bandwidth in the UHF band, 6.30 to 8.31 dBi gain, 1.53:1 standing wave ratio or less, within ${\pm}0.2dB$ gain flatness in the azimuth radiation pattern, elevation radiation pattern of 3dB beam width was 15.62 to 15.84 degrees. The test result meets all requirements specifications.

• Applied Chemistry for Engineering
• /
• v.30 no.4
• /
• pp.429-434
• /
• 2019

A lateral flow immunoassay platform utilizing antibody functionalized water soluble CdSe/ZnS semiconductor quantum dots (QDs) was developed for the analysis of human serum amyloid A-1 (hSAA1) in a buffer solution. hSAA1 was chosen as a target protein because it is regarded as a potential biomarker associated with early diagnosis and prognosis in patients of lung cancer. The immunoassay strip on a nitrocellulose membrane was fabricated by spraying two lines composed of a test line with a monoclonal antibody against hSAA1 (10G1) (anti hSAA1) and a control line of anti-chicken IgY. While the CdSe/ZnS QDs synthesized in an organic phase were transferred to a water phase by ligand exchange using carboxylic acid modified alkane thiol. The QDs was then conjugated to monoclonal antibody against hSAA1 (14F8) [anti hSAA1 (14F8)] and used as a fluorescent detection probe. The sequential lateral flow of hSAA1 in different concentration and QDs-anti hSAA1 (14F8) complex allowed to form the surface sandwich complex of anti hSAA1 (10G1)/hSAA1/QD-anti hSAA1 (14F8), which was then analyzed using fluorescence microscope. A 100 nM concentration of hSAA1 protein can be detected by naked eyes under an optimized lateral flow buffer condition with a sensing time of 5 mins.

• Korean Journal of Remote Sensing
• /
• v.34 no.6_2
• /
• pp.1179-1192
• /
• 2018

In order to detect the Antarctic Polar Front (PF) among the main fronts in the Southern Ocean, this study is based on the combinations of satellite-based sea surface temperature (SST) and height (SSH) observations. For accurate PF detection, we classified the signals as front or non-front grids based on the Bayesian decision theory from daily SST and SSH datasets, and then spatio-temporal synthesis has been performed to remove primary noises and to supplement geographical connectivity of the front grids. In addition, sea ice and coastal masking were employed in order to remove the noise that still remains even after performing the processes and morphology operations. Finally, we selected only the southernmost grids, which can be considered as fronts and determined as the monthly PF by a linear smoothing spline optimization method. The mean positions of PF in this study are very similar to those of the PFs reported by the previous studies, and it is likely to be well represents PF formation along the bottom topography known as one of the major influences of the PF maintenance. The seasonal variation in the positions of PF is high in the Ross Sea sector (${\sim}180^{\circ}W$), and Australia sector ($120^{\circ}E-140^{\circ}E$), and these variations are quite similar to the previous studies. Therefore, it is expected that the detection approach for the PF position applied in this study and the final composite have a value that can be used in related research to be carried out on the long term time-scale.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.1
• /
• pp.78-85
• /
• 2019

Membrane proteins are involved in many common diseases, including heart disease and cancer. In various disease states, such as cancer, abnormal signaling pathways that are related to the membrane proteins cause the cells to divide out of control and the expression of membrane proteins can be altered. Membrane proteins have the hydrophobic environment of a lipid bilayer, which makes an analysis of the membrane proteins notoriously difficult. Therefore, this study evaluated the efficacy of two different methods for optimal membrane protein extraction. High-speed centrifuge and reagent-based method with a -/+ filter aided sample preparation (FASP) were compared. As a result, the high-speed centrifuge method is quite effective in analyzing the mitochondrial inner membranes, while the reagent-based method is useful for endoplasmic reticulum membrane analysis. In addition, the function of the membrane proteins extracted from the two methods were analyzed using GeneGo software. GO processes showed that the endoplasmic reticulum-related responses had higher significance in the reagent-based method. An analysis of the process networks showed that one cluster in the high-speed centrifuge method and four clusters in the reagent-based method were visualized. In conclusion, the two methods are useful for the analysis of different subcellular membrane proteins, and are expected to assist in selecting the membrane protein extraction method by considering the target subcellular membrane proteins for study.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.1
• /
• pp.141-148
• /
• 2021

In some intersections or busy traffic roads, there are more pedestrians in a specific period of time, and there are many traffic accidents caused by road congestion. Especially at the intersection where there are schools nearby, it is particularly important to protect the traffic safety of students in busy hours. In the past, when designing traffic lights, the safety of pedestrians was seldom taken into account, and the identification of motor vehicles and traffic optimization were mostly studied. How to keep the road smooth as far as possible under the premise of ensuring the safety of pedestrians, especially students, will be the key research direction of this paper. This paper will focus on person, motorcycle, bicycle, car and bus recognition research. Through investigation and comparison, this paper proposes to use YOLO v4 network to identify the location and quantity of objects. YOLO v4 has the characteristics of strong ability of small target recognition, high precision and fast processing speed, and sets the data acquisition object to train and test the image set. Using the statistics of the accuracy rate, error rate and omission rate of the target in the video, the network trained in this paper can accurately and effectively identify persons, motorcycles, bicycles, cars and buses in the moving images.

• Clean Technology
• /
• v.26 no.4
• /
• pp.293-303
• /
• 2020

According to the World Health Organization (WHO), air pollution is a typical health hazard, resulting in about 7 million premature deaths each year. Sulfur dioxide (SO2) is one of the major air pollutants, and the combustion process with sulfur-containing fuels generates it. Measuring SO2 generation in large combustion environments in real time and optimizing reduction facilities based on measured values are necessary to reduce the compound's presence. This paper describes the concentration measurement for SO2, a particulate matter precursor, using a wavelength modulation spectroscopy (WMS) of tunable diode laser absorption spectroscopy (TDLAS). This study employed a quantum cascade laser operating at 7.6 ㎛ as a light source. It demonstrated concentration measurement possibility using 64 multi-absorption lines between 7623.7 and 7626.0 nm. The experiments were conducted in a multi-pass cell with a total path length of 28 and 76 m at 1 atm, 296 K. The SO2 concentration was tested in two types: high concentration (1000 to 5000 ppm) and low concentration (10 ppm or less). Additionally, the effect of H2O interference in the atmosphere on the measurement of SO2 was confirmed by N2 purging the laser's path. The detection limit for SO2 was 3 ppm, and results were compared with the electronic chemical sensor and nondispersive infrared (NDIR) sensor.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.3
• /
• pp.181-192
• /
• 2022

Active vibration control system(AVCS) for helicopter enables to control the vibration generated from the main rotor and has the superb vibration reduction performance with low weight compared passive vibration reduction device. In this paper, FxLMS algorithm-based vibration control software of the light civil helicopter tansmits the control command calculated using the signals of the tachometer and accelerometers to the circular force generator(CFG) is developed and verified. According to the RTCA DO-178C/DO-331, the vibration control software is developed through the model based design technique, and real-time operation performance is evaluated in PILS(processor in-the loop simulation) and HILS(hardware in-the loop simulation) environments. In particular, the reliability of the software is improved through the LDRA-based verification coverage in the PIL environments. In order to AVCS to light civil helicopter(LCH), the dynamic response characteristic model is obtained through the ground/flight tests. AVCS configuration which exhibits the optimal performance is determined using system optimization analysis and flight test and obtain STC certification.