• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.813-816
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• 2004

This study was performed to investigate bonding performance of epoxy resins for repairing of cracks in concrete, as a part of project to establish quality control standard for epoxy resins. In the slant shear strength test for hard and soft type epoxy, hard type was higher about 3 times than soft one. From the results, it is thought that hard type is suitable for load carrying. Injection of epoxy resin in the notch made flexural strength increase about $47\%$ over the specimen that epoxy resin is not injected. There were no differences in bonding performances with viscosity. Application of epoxy resin on the wet concrete surface made slant shear strength decrease about $46\%$, but similar performance to the case of application on the dry surface appeared by using epoxy resin for wet condition.

• 한국항만학회지
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• 제14권2호
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• pp.233-239
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• 2000

The expansion of old road is needed in constructing the entrance at the $\bigcirc$$\bigcirc$I/C road in $\bigcirc$$\bigcirc$city. To strength the national competition, many agents who concerned do their best for finishing that construction early as soon as possible. In generally, soil embankment on soft foundation is caused to reduce the stability by making the settlement of ground surface due to the over load. Thus, we try to make it stable by building EPS embankment construction which in our working place is one kind of the method of light embankment construction after excavating the original ground.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.219-224
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• 1999

The expansion of old road is needed in construction the entrance at the $\bigcirc$$\bigcirc$I/C road in $\bigcirc$$\bigcirc$city. To strength the national competition, many agents who concerned do their best for finishing that construction early as soon as possible. In generally, soil embankment on soft foundation is caused to reduce the stability by making the settlement of ground surface due to the over load. Thus, we try to make it stable by building EPS embankment construction which in our working place is one kind of the method of light embankment construction after excavating the original ground.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 추계학술대회 초록집
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• pp.140-140
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• 2009

• The Journal of Advanced Prosthodontics
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• 제7권2호
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• pp.151-159
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• 2015

PURPOSE. To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS. A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non- quantitatively. RESULTS. All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION. The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

• 비파괴검사학회지
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• 제32권5호
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• pp.469-483
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• 2012

인체 연조직에서 기계적인 진동의 전달 특성은 조직의 탄성 특성에 의존한다. 연조직의 진동 특성으로부터 암이나 종양을 진단할 수 있기 때문에 진동의 전달 특성에 대한 연구는 중요한 의미를 가진다. 이 논문은 연조직의 표면에 위치하는 여러 형태의 응력 진동원에 의해 연조직 내에 발생되는 변위 패턴을 분석하고 비교하였다. 진동원으로는 수직하중, 접선하중, 그리고 면외전단하중이 고려되었다. 점탄성 단일층에서의 변위에 대한 이론적 표현식을 구하였고, 수치계산은 반공간 및 무한평판조직에서 수행되었다. 그리고 유한크기조직에서의 변위패턴을 유한요소법으로 시뮬레이션하였다. 응력 형태, 진동원 크기 및 주파수, 그리고 경계면이 변위에 미치는 영향이 분석되었다.

• 한국지반환경공학회 논문집
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• 제20권2호
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• pp.29-40
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• 2019

최근 터널 시공 시 여러 위험요인을 감안하여 보다 안전한 터널의 시공을 위하여 해상이나 하상 밑의 연약지반에서, 도심터널공사나 주요 구조물 하부 통과를 위해서 기계화 시공의 빈도가 높아지고 있다. 그러나 굴착으로 인한 지표면의 침하거동 산정이 어려워 간편하게 예측하는 식이 필요한 실정이다. 따라서 본 연구에서는 연약지반에 병렬로 터널이 시공되어지는 경우 침하거동에 대해 보다 간단한 식과 기존에 Peck(1969)이 제안한 이론을 근거로 연약지반 및 대구경 shield 터널에서 적용 가능한 수정식을 제안하고자 하였다. 이를 위해 최대 침하량, 지반조건에 따른 침하범위, 병렬시공에 따른 간섭 체적손실 등의 장기간의 계측값을 분석하였다. 그 결과 굴착면 상부가 퇴적점토인 연약지반에서 간편하게 최대 침하량을 산정할 수 있는 식을 제시하였는데, Peck(1969)의 식보다 국내 계측데이터에 더 적합한 것으로 나타났다.

• 한국지반환경공학회 논문집
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• 제23권8호
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• pp.17-22
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• 2022

공용 중에 연약지반의 침하로 발생된 교량 접속부의 단차 개선을 위해 도로관리기관에서는 지속적으로 덧씌우기를 실시하고 있다. 본 연구에서는 연약지반 내에 건설된 교량 9개소에 대해 접속부의 침하량을 추정하고자 1GHz 안테나를 차량에 탑재한 지표투과레이더 장비를 이용하였다. 포장 내부 조사가 가능한 지표투과레이더 기술로 아스팔트 도로에서 깊이 1m 수준까지 효과적으로 포장두께의 측정이 가능하였다. 노면 변형 조사결과와는 다르게, 9개 교량 접속부에서 측정된 포장두께 변화량은 최소 50mm에서 최대 600mm로 상당하였으며, 공동(空洞)의 발생 가능성도 높았다. 또한 각 교량 접속부의 부위별로는 증가된 포장두께의 차이가 50~250mm로 나타나 부등침하 위험이 존재하였다. 본 연구에서 지표투과레이더 결과에 근거하여 주행성 개선 및 침하부 유지관리 방안을 제시하였다.

• 한국분말재료학회지
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• 제29권6호
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• pp.459-467
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• 2022

Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.411-411
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• 2012

Over the recent years, surface enhanced Raman spectroscopy (SERS) has dramatically grown as a label-free detecting technique with the high level of selectivity and sensitivity. Conventional SERS-active nanostructured layers have been deposited or patterned on rigid substrates such as silicon wafers and glass slides. Such devices fabricated on a flexible platform may offer additional functionalities and potential applications. For example, flexible SERS-active substrates can be integrated into microfluidic diagnostic devices with round-shaped micro-channel, which has large surface area compared to the area of flat SERS-active substrates so that we may anticipate high sensitivity in a conformable device form. We demonstrate fabrication of flexible SERS-active nanostructured substrates based on soft-lithography for simple, low-cost processing. The SERS-active nanostructured substrates are fabricated using conventional Si fabrication process and inkjet printing methods. A Si mold is patterned by photolithography with an average height of 700 nm and an average pitch of 200 nm. Polydimethylsiloxane (PDMS), a mixture of Sylgard 184 elastomer and curing agnet (wt/wt = 10:1), is poured onto the mold that is coated with trichlorosilane for separating the PDMS easily from the mold. Then, the nano-pattern is transferred to the thin PDMS substrates. The soft lithographic methods enable the SERS-active nanostructured substrates to be repeatedly replicated. Silver layer is physically deposited on the PDMS. Then, gold nanoparticle (AuNP) inks are applied on the nanostructured PDMS using inkjet printer (Dimatix DMP 2831) to deposit AuNPs on the substrates. The characteristics of SERS-active substrates are measured; topology is provided by atomic force microscope (AFM, Park Systems XE-100) and Raman spectra are collected by Raman spectroscopy (Horiba LabRAM ARAMIS Spectrometer). We anticipate that the results may open up various possibilities of applying flexible platform to highly sensitive Raman detection.