• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2007년도 제48회 학술심포지움 및 추계국제학술대회
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• pp.80.2-80.2
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• 2007

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• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.1-11
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• 2012

Purpose: The purpose of this study was to evaluate the bone regeneration capacity of silk fibroin (SF) when combined with beta tricalcium phosphate (${\beta}$-tricalcium phosphate [TCP]) and rh-bone morphogenetic protein (BMP) in vivo by micro-computed tomography (CT), soft x-ray, and histological analysis. Methods: A total of 56 critical size defects formed by a trephine bur made on 28 adult female Spague-Dawley rats were used for this study and the defect size was 5.0 mm in diameter. The defects were transplanted with (1) no graft material (raw defect), (2) autogenous bone, (3) SF ($10{\mu}g$), (4) SF-BMP ($10{\mu}g$, $0.8{\mu}g$ each), and (5) SF+${\beta}$-TCP ($10{\mu}g$). At 4 and 8 weeks after operation, the experimental animals were sacrificed. Samples were evaluated with soft x-ray, histological examinations and 3-dimensional micro-CT analysis. Results: In the 3-dimensional micro-CT evaluation, bone volume and bone surface data were higher in the SF-BMP ($12.8{\pm}1.5$, $138.6{\pm}45.0$ each) (P<0.05) and SF-TCP ($12.3{\pm}1.5$, $144.9{\pm}30.9$ each) group than in the SF group ($6.1{\pm}3.3$, $77.2{\pm}37.3$ each) (P<0.05), except for the autogenous group ($15.0{\pm}3.0$, $190.7{\pm}41.4$ each) at 4 weeks. At 8 weeks, SF-BMP ($16.8{\pm}3.5$, $173.9{\pm}34.2$ each) still revealed higher (P<0.05) bone volum and surface, but SF-TCP ($11.3{\pm}1.5$, $1132.9{\pm}52.1$ each) (P=0.5, P=0.2) revealed the same or lower amount compared with the SF group ($13.8{\pm}2.7$, $127.5{\pm}44.8$ each). The % of bone area determined by radiodensity was higher in the SF-TCP ($31.4{\pm}9.1%$) and SF-BMP ($36.2{\pm}16.2%$) groups than in the SF ($19.0{\pm}10.4$) group at the period of 4 weeks. Also, in the histological evaluation, the SF-BMP group revealed lower inflammation reaction, lower foreign body reaction and higher bone healing than the SF group at postoperative 4 weeks and 8 weeks. The SF-TCP group revealed lower inflammation at 4 weeks, but accordingly, as the TCP membrane was absorbed, inflammatory and foreign body reaction are increased at 8 weeks. Conclusion: The current study provides evidence that the silk fibrin can be used as an effective grafted material for tissue engineering bone generation through a combination of growth factor or surface treatment.

• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.203-207
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• 1998

After etching Al-Cu alloy films using $SiCl_4/Cl_2/He/CHF_3$ plasma, a corrosion phenomenon on the metal surface has been studied with XPS (X-ray photoelectron spectroscopy) and SEM (Scanning electron microscopy). In Al-Cu alloy system, the corrosion occurs rapidly on the etched surface by residual chlorine atoms. To prevent the corrosion, the $SF_6$ plasma treatment subsequent to the etch has been carried out. A passivation layer is formed by fluorine-related compounds on etched Al-Cu alloy surface after $SF_6$ treatment, and the layer suppresses effectively the corrosion on the surface as the RF power of $SF_6$ treatment increases. The corrosion could be suppressed successfully with $SF_6$ treatment in the RF power of 150watts.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.61-66
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• 2008

Impact behavior of large SF590A (Fe-0.65C-1.5Mn-0.035P-0.035S-0.3Cr-0.15Mo-0.4Ni-0.3Cu) forged propeller shaft was studied in this study. Charpy impact specimens were prepared from the forged product with different heat number. The impact value of each specimen with different heat number tends to vary greatly depending on the prior austenite grain size and, less significantly, on the amount of sulfur. The dominant metallurgical factors affecting impact behavior of SF590A forged product are discussed based on fractographic and metallographic observations.

• 대한전자공학회논문지SD
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• 제42권5호
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• pp.55-62
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• 2005

본 논문에서는 공간-주파수 OFDM (SF-OFDM) 기법을 위한 효율적인 심볼 검출 알고리즘이 제안되고, 이를 기반으로 하는 SF-OFDM 무선 LAN 기저대역 프로세서의 구현 결과가 제시된다. SF-OFDM 기법에서 부반송파의 개수가 적은 경우 부채널간 간섭이 발생하게 되며, 이러한 간섭은 다이버시티 시스템의 성능을 크게 저하시킨다. 제안된 알고리즘은 부채널간 간섭을 병렬적으로 제거함으로써 기존 알고리즘에 비해 큰 성능 이득을 얻는다. 컴퓨터 모의실험을 통한 비트오류율 (BER) 성능 평가 결과 두개의 송${\cdot}$수신 안테나를 사용하는 경우 10-4의 BER에서 기존 알고리즘에 비해 약 3 dB의 성능이득을 얻음을 확인하였다. 제안된 심볼 검출 알고리즘이 적용된 SF-OFDM 무선 LAN 시스템의 패킷오류율 (PER), link throughput 및 coverage 성능이 분석되었다. 최대 전송률의 $80\%$를 목표 throughput으로 설정 했을 때, SF-OFDM 기반 무선 LAN 시스템은 기존의 IEEE 802.11a 무선 LAN 시스템에 비해 약 5.95 dB의 SNR 이득과 3.98 미터의 coverage 이득을 얻을 수 있었다. 제안된 알고리즘이 적용된 SF-OFDM 무선 LAN 기저대역 프로세서는 하드웨어 설계 언어를 통해 설계되었으며, 0.18um 1.8V CMOS 표준 셀 라이브러리를 통해 합성되었다. 제시된 division-free 하드웨어 구조와 함께, 구현된 프로세서의 총 게이트 수는 약 945K개였으며, FPGA 테스트 시스템을 통해 실시간 검증 및 평가되었다.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.474-482
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• 2014

PURPOSE. To assess removable prosthetic restoration tolerance according to the patient section of the short form of the Gagging Problem Assessment Questionnaire (GPA-pa SF) and the influence of gender, education level and prosthesis type and denture-related mucosal irritation on the GPA-pa SF scores before treatment and over a period of two months after prosthesis insertion. MATERIALS AND METHODS. 130 participants who required removable prosthesis were surveyed with a standard form that included questions regarding age, gender, education level, dental attendance, and prosthetic restoration type. Participants answered the GPA-pa SF before restoration (T0) and 1 day (T1), 2 days (T2), 15 days (T3), 1 month (T4), and 2 months (T5) after prosthesis insertion. RESULTS. Of the 130 participants, 110 participants completed the prosthetic restoration procedure, but only 93 of these were able to use the prosthesis over the two-month period. The mean GPA-pa SF score obtained at T0 was higher than the scores obtained at the other periods in the total of the sample. Significant difference was present between mean scores obtained at T0-T1 and T2-T3 than scores obtained at other periods (P<.05). Female participants and participants with denture-related mucosal irritation had higher GPA-pa SF scores at all time points analysed. Significant difference was present between mean GPA-pa SF scores obtained at T2-T3 than scores obtained at other periods for females and participants with denture-related mucosal irritation (P<.05). Education level and prosthesis type did not significantly influence the GPA-pa SF score at any time point analysed (P>.05). CONCLUSION. GPA-pa SF scores were higher before the restoration procedure began, and decreased over time with the use of prosthesis. Gender and denture-related mucosal irritation affected the GPA-pa SF scores.

• ETRI Journal
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• 제21권3호
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• pp.16-21
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• 1999

After etching Al-Cu alloy films using SiCl4/Cl_2/He/CHF3 mixed gas plasma, the corrosion phenomenon at the grain boundary of the etched surface and a passivation layer on the etched surface with an SF6 plasma treatment subsequent to the etching were studied. In Al-Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms, and it occurs dominantly at the grain boundaries rather than the crystalline surfaces. To prevent corrosion, the SF6 gas plasma treatment subsequent to etching was carried out. The passivation layer is composed of fluorine-related compounds on the etched Al-Cu surface after the SF6 treatment, and it suppresses effectively corrosion on the surface as the SF6 treatment pressure increases. Corrosion could be suppressed successfully with the SF6 treatment at a total pressure of 300 mTorr. To investigate the reason why corrosion could be suppressed with the SF6 treatment, behaviors of chlorine and fluorine were studied by various analysis techniques. It was also found that the residual chlorine incorporated at the grain boundary of the etched surface accelerated corrosion and could not be removed after the SF6 plasma treatment.

• Steel and Composite Structures
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• 제51권3호
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• pp.243-260
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• 2024

Thirteen self-compacting recycled concrete filled aluminium tubular (SCRCFAT) columns were tested under concentric compression loads. The effects of the replacement ratio of the recycled concrete aggregate (RCA) and steel fibre (SF) reinforcement on the structural performance of the SCRCFAT columns were studied. A control specimen (C000) was cast with normal concrete without SF to be reference for comparison. Twelve columns were cast using RCA, six columns were cast using concrete incorporating 2% SF while the rest of columns were cast without SF. Failure mode, ductility, ultimate load capacity, axial deformation, ultimate strains, stress-strain response, and stiffness of the SCRCFAT columns were studied. The results showed that, the peak load of tested SCRCFAT columns incorporating 5-100 % RCA without SF reduced by 2.33-11.28 % compared to that of C000. Conversely, the peak load of tested SCRCFAT columns incorporating 5-100% RCA in addition to 2% SF increased by 21.1-40.25%, compared to C000. Consequently, the ultimate axial deformation (Δ) of column C100 (RCA=100% and SF 0%) increased by about 118.9 % compared to C000. The addition of 2% SF to the concrete mix decreased the axial deformation of SCRCFAT columns compared to those cast with 0% SF. Moreover, the stiffness of the columns cast without SF decreased as the RCA % increased. In contrast, the columns stiffness cast with 2% SF increased by 26.28-89.7 % over that of C000. Finally, a theoretical model was proposed to predict the ultimate loads tested SCRCFAT columns and the obtained theoretical results agreed well with the experimental results.

• Molecules and Cells
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• 제24권3호
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• pp.372-377
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• 2007

The orphan nuclear receptor, SF-1, plays a pivotal role in the development and differentiation of the endocrine and reproductive systems, and also regulates the transcription of a host of genes, including those encoding several steroidogenic enzymes and gonadotropins. We found that a previously unidentified repressor, EID-1, is an SF-1-interacting protein that inhibits the transactivation of SF-1. A transient transfection assay revealed that EID-1 inhibits SF-1, but not LRH-1, $ERR{\gamma}$, or mCAR. Using the yeast two hybrid and GST pull-down assays, we determined that EID-1 interacted strongly with SF-1. In addition, it colocalized with SF-1 in mammalian cells and interacted specifically with the AF-2 domain of SF-1, competing with SRC-1 to inhibit SF-1 transactivation. EID-1 is expressed in the mouse testis, and its expression decreases during testis development. The results of the present study suggest that EID-1 can act as a repressor, regulating the function of SF-1.

• 한국지형학회지
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• 제25권1호
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• pp.67-80
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• 2018

This study used aerial and terrestrial images to build a three-dimensional model of cliffs located in Pado beach using SfM (Structure from Motion) techniques. Using both images, the study purposed to reduce the shadow areas that were found when using only aerial images. Accuracy of the two campaigns was assessed by root mean square error, and monitored by M3C2 (Multiscale Model to Model Cloud Comparison) method. The result of the M3C2 in closed areas such as sea cave and notch did not express the landforms partly. However, eroded debris on sea cliffs were detected as eroded area by M3C2, as well as in captured pictures by multi-camera. The result of this study showed the applicability of multi-camera and SfM in monitoring changes of sea cliffs.