• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권6호
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• pp.259-268
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• 2018

Objectives: The purpose of this study was to evaluate the synergic effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) and low-level laser therapy (LLLT) on bisphosphonate-treated osteoblasts. Materials and Methods: Human fetal osteoblast cells (hFOB 1.19) were cultured with $100{\mu}M$ alendronate. Low-level Ga-Al-As laser alone or with 100 ng/mL rhBMP-2 was then applied. Cell viability was measured with MTT assay. The expression levels of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor (M-CSF), and osteoprotegerin (OPG) were analyzed for osteoblastic activity inducing osteoclastic activity. Collagen type and transforming growth factor beta-1 were also evaluated for bone matrix formation. Results: The results showed that rhBMP-2 and LLLT had a synergic effect on alendronate-treated osteoblasts for enhancing osteoblastic activity and bone matrix formation. Between rhBMP-2 and LLLT, rhBMP-2 exhibited a greater effect, but did not show a significant difference. Conclusion: rhBMP-2 and LLLT have synergic effects on bisphosphonate-treated osteoblasts through enhancement of osteoblastic activity and bone formation activity.

• 한국분말재료학회지
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• 제29권1호
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• pp.14-21
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• 2022

In the powder bed fusion (PBF) process, a 3D shape is formed by the continuous stacking of very fine powder layers using computer-aided design (CAD) modeling data, following which laser irradiation can be used to fuse the layers forming the desired product. In this method, the main process parameters for manufacturing the desired 3D products are laser power, laser speed, powder form, powder size, laminated thickness, and laser diameter. Stainless steel (STS) 316L exhibits excellent strength at high temperatures, and is also corrosion resistant. Due to this, it is widely used in various additive manufacturing processes, and in the production of corrosion-resistant components with complicated shapes. In this study, rectangular specimens have been manufactured using STS 316L powder via the PBF process. Further, the effect of heat treatment at 800 ℃ on the microstructure and hardness has been investigated.

• 한국건축시공학회지
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• 제23권2호
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• pp.113-121
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• 2023

본 연구에서는 부산물(석분 슬러지, 고로슬래그, 제강슬래그, 폐콘크리트 슬러지, 바텀애시) 5종과 클링커 내 중금속 분석을 위한 레이져 유도 플라즈마 분광법(LIBS) 적용성과 재현성 검토를 실험적으로 수행하였다. 클링커를 포함한 6종의 부산물 시료에 대한 ICP-MS, XRF, LIBS 분석 결과, 정량적 분석에서 ICP와 XRF의 차이가 확인되었으나, LIBS 분석은 표준분석과 일치하지 않고 시료의 정성적인 분석만 가능하였다. LIBS를 통한 정량적 분석을 위하여 Cd, Pb, Hg에 대하여 LIBS 분석 파장(Cd - 214.44nm, Pb - 405.78nm, Hg - 253.65nm)을 설정하였고, 농도별(1~1000ppm) 용액에 함침하여 건조시킨 멤브레인 표면에 레이져를 조사한 결과, 스펙트럼 강도와 농도 사이의 상관관계를 확인할 수 있었다.

• 센서학회지
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• 제32권5호
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• pp.320-327
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• 2023

In this study, an FPGA-based sealer inspection system was developed to inspect the sealer applied to install vehicle glass on a car body. The sealer is a liquid or paste-like material that promotes adhesion such as sealing and waterproofing for mounting and assembling vehicle parts to a car body. The system installed in the existing vehicle design parts line does not detect the sealer in the glass rotation section and takes a long time to process. This study developed a line laser camera sensor and an FPGA vision signal processing module to solve this problem. The line laser camera sensor was developed such that the resolution and speed of the camera for data acquisition could be modified according to the irradiation angle of the laser. Furthermore, it was developed considering the mountability of the entire system to prevent interference with the sealer ejection machine. In addition, a vision signal processing module was developed using the Zynq-7020 FPGA chip to improve the processing speed of the algorithm that converted the profile to the sealer shape image acquired from a 2D camera and calculated the width and height of the sealer using the converted profile. The performance of the developed sealer application inspection system was verified by establishing an experimental environment identical to that of an actual automobile production line. The experimental results confirmed the performance of the sealer application inspection at a level that satisfied the requirements of automotive field standards.

• 보존과학회지
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• 제32권3호
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• pp.377-384
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• 2016

철불의 개금 시 표면에 남아 있는 옻칠 제거 방법에는 물리적인 방법과 화학적인 방법을 사용하고 있으나, 표면 손상 및 약품 사용으로 인한 환경오염, 보존과학자의 건강에도 매우 유해하다. 그래서 본 연구에서는 비접촉식이고 친환경적인 Nd:YAG 레이저를 이용하여 옻칠 제거 실험을 실시하였다. 시편은 크기가 $5{\times}5cm$인 철제(Fe 99.9%)시편 표면을 균일하게 연마한 후 생칠을 도포 횟수를 달리하여 각각 $10{\mu}m$, $20{\mu}m$, $30{\mu}m$의 두께 차이로 제작하였다. 본 실험에서 사용된 레이저기기는 Nd:YAG 레이저로, 적외선 영역의 1064 nm(160~800 mJ)와 가시광선 영역인 532nm(50~350 mJ)의 두 가지 파장 모드를 이용하였다. 실험은 레이저 파장 에너지 조사 횟수 등에 따른 시편 표면의 변화를 조사하였다. 레이저 조사 전 후 표면을 실체현미경과 SEM 관찰, 비접촉 표면 조도 측정기, FT-IR 등을 이용하여 옻칠의 제거 및 잔류 여부를 알아보았다. 분석 결과 1064 nm 파장을 이용하여 $1.0J/cm^2$ 밀도에서 표면 손상 없이 $10{\mu}m$, $20{\mu}m$ 두께의 옻칠이 제거됨을 확인할 수 있었다. 이와 같은 결과를 통해 철불 개금 시 잔류하고 있는 옻칠 제거 방법으로 Nd:YAG 레이저가 효율적임을 본 실험을 통해 알 수 있었다. 향후 금속뿐만 아니라 목칠 가구 등 다양한 재질의 연구가 이루어지면 표면 손상 없이 옻칠을 제거 하는데 효과적으로 활용 가능할 것으로 본다.

• 방사성폐기물학회지
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• 제8권3호
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• pp.181-188
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• 2010

레이저 용발법에 의한 금속 표면 제염특성을 평가하였다. 레이저로는 파장 532 nm, 펄스에너지 150 mJ, 펄스폭 5 ns의 큐스위치 Nd:YAG를 적용하였고, 금속 표면에 $CsNO_3$, $Co(NH_4)_2(SO_4)_2$, $Eu_2O_3$ 그리고 $CeO_2$를 오염시켜 이들의 제염 특성을 평가하였다. 제염 변수로는 레이저 적용횟수, 레이저 에너지 밀도 및 레이저 조사 각도 특성을 평가하였으며 각각 8, 13.3 J/$cm^2$ 및 $30^{\circ}$의 최적 조건을 확인하였다. 제염 효율은 오염성분의 비점과 관련이 있었으며 $CsNO_3>Co(NH_4)_2(SO_4)_2>Eu_2O_3>CeO_2$ 순이었다. 또한 여러 에너지 밀도 조건에서 스테인레스 스틸 재질의 식각 깊이 제어 특성을 규명하였다.

• Korean Journal of Acupuncture
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• 제27권1호
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• pp.125-142
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• 2010

Objectives: The purpose of this study was to identify the effectiveness of neuronal activities for the acupuncture and laser acupuncture application. Methods: The subject were divided into 7 groups as control group without acupuncture, acupuncture treatment with tonify manipulation with the direction of channel at HT9, LR1(AT-A), acupuncture treatment with purge manipulation against the direction of channel at HT3, Kl10(AT-B), acupuncture treatment with tonify manipulation with the direction of channel at HT9, LR1 and purge manipulation against the direction of channel at HT3, KI10(AT-C), laser acupuncture treatment with red light 658 nm at HT9, LR1(LAT-A), laser acupuncture treatment with green light 532 nm at HT3, KI10(LAT-B), laser acupuncture treatment with red light 658 nm at HT9, LR1 and green light 532 nm at HT3, KI10(LAT-B). Antiapopotic effect of acupuncture was observed by Bax, Bcl-2 and cytochrome C. Neuroprotective effect of acupuncture was observed by cresyl violet and ChAT. Results: AT-A, AT-B, AT-C, LAT-A, LAT-B and LAT-C groups were significantly increased comparing the control groups in expression ChAT and in neuroprotective effect by cresyl violet. AT-A, AT-B, AT-C, LAT-A, LAT-B and LAT-C groups were significantly decreased comparing the control groups in expression Bax. AT-C, LAT-A, LAT-B and LAT-C groups were significantly increased comparing the control groups in expression Bcl-2. AT-A, AT-B, AT-C, LAT-A, LAT-B and LAT-C groups were significantly decreased comparing the control groups in Bax/Bcl-2 ratio. LAT-B and LAT-C groups were significantly decreased comparing the control groups in expression cytochrome C. Conclusions: The acupuncture with tonify and purge manipulation and laser acupuncture with red and green light could be effective for antiapopotic and neuroprotective effect in focal brain ischemia.

• 한국임상수의학회지
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• 제30권5호
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• pp.346-352
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• 2013

본 연구는 다이오드레이저가 골관절염에 주는 영향을 평가하기 위해 실시되었다. 연구에는 10주령의 수컷 Sprague-Dawley 랫드 60마리를 사용하였고 전십자인대의 절단 (ACLT)으로 골관절염을 유발하였다. 대조군, sham군, ACLT군, ACLT와 레이저조사를 병행한 군 (ACLT+L), ACLT와 meloxicam 투약을 병행한 군 (ACLT+M)의 다섯 개의 실험군으로 나누어 연구를 진행하였다. 8주간의 연구 기간 동안 808-nm indium-gallium-arsenide (InGaAs) 다이오드레이저 조사 방법으로 Low-level laser therapy (LLLT)를 일주일에 두 번 랫드의 수술 한 오른쪽 다리에 조사하였다. 수술 후 2주, 4주, 8주에 방사선학적, 형태학적, 조직병리학적 평가를 실시하였다. 8주에 실시한 방사선학적 평가와 일반 혈액검사, 혈청 화학 검사에서는 군 간의 유의한 차이가 나타나지 않았다. 형택학적 방법과 조직병리학적 방법으로 수술 후 2주, 4주, 8주의 ACLT+L 군과 sham 군을 비교 했을 때 ACLT+L 군에서 유의하게 연골의 손상정도가 높은 것으로 나타났다. ACLT+M 군 또한 sham 군과 비교했을 때 연골의 손상이 심한 것으로 나타났다. LLLT는 ACLT 모델에서 골관절염을 예방하는 효과는 제한적이었으며, 오히려 연골의 손상을 가속화 시키는 것으로 평가 되었다. LLLT가 세포의 생존에는 영향을 주지 않으므로 레이져에 의한 직접적인 연골손상 발생보다는 레이저의 통증완화효과로 인해 불안정한 무릎관절을 계속해서 사용함으로써 연골의 손상이 가속화 된 것으로 생각 된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.115-115
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• 2015

Many efforts have been devoted on chemical modification of graphene layer to modulate its electrical properties. In the previous report, laser irradiation on the CYTOP (Amorphous Fluoropolymer) covered graphene layer induces chemical modification wherein carbon fluoride is formed on the graphene surface. This results in the insulating I-V characteristics, which have been attracting much research interests on it. However, the direct analytical evidence of the fluoride formation on graphene surface is not yet studied. In this work we investigated what happened on the CYTOP/graphene interface during photon irradiation using spatially resolved photoemission spectroscopy method. It is found that the soft x-ray (614 eV) induces desorption of fluoride atoms from the CYTOP and change di-fluoride form to mono-fluoride. As the photo-induced fluorine desorption is continue strong dipole field generated by initial di-fluoride forms is gradually decreased, resulting in the overall binding energy shift of the C 1s core levels. Both photo-modified CYTOP and CYTOP starts to desorb above $286^{\circ}C$ (~ 0.047 eV), which means that no strong chemical interaction between CYTOP and graphene is established.

• Biomolecules & Therapeutics
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• 제24권3호
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• pp.305-311
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• 2016

Mitochondria-targeted vitamin E (MVE) is designed to accumulate within mitochondria and is applied to decrease mitochondrial oxidative damage. However, the protective effects of MVE in skin cells have not been identified. We investigated the protective effect of MVE against UVB in dermal fibroblasts and immortalized human keratinocyte cell line (HaCaT). In addition, we studied the wound-healing effect of MVE in animal models. We found that MVE increased the proliferation and survival of fibroblasts at low concentration (i.e., nM ranges). In addition, MVE increased collagen production and downregulated matrix metalloproteinase1. MVE also increased the proliferation and survival of HaCaT cells. UVB increased reactive oxygen species (ROS) production in fibroblasts and HaCaT cells, while MVE decreased ROS production at low concentration. In an animal experiment, MVE accelerated wound healing from laser-induced skin damage. These results collectively suggest that low dose MVE protects skin from UVB irradiation. Therefore, MVE can be developed as a cosmetic raw material.