• 마이크로전자및패키징학회지
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• 제29권2호
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• pp.43-48
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• 2022

인쇄전자소자의 금속배선 적용을 위해 스크린 프린팅 Ag/폴리이미드(polyimide, PI) 사이의 계면접착력을 85℃/85% 상대습도의 고온/고습 처리 시간에 따라 PI 필링을 통한 90° 필 테스트로 평가하였다. 고온/고습 처리 전 필 강도는 약 25.99±1.47 gf/mm이었고, 500시간 동안 고온/고습 처리 후 필 강도는 6.05±0.54 gf/mm까지 지속적으로 감소하였다. 박리 파면에 대해 X-선 광전자 분광법 분석 결과, 이는 Ag/PI 계면으로 수분이 지속적으로 침투하여 계면 근처 PI 일부가 가수분해되어 weak boundary layer를 형성하기 때문이고, 이로 인해 고온/고습 처리 전 Ag/PI 계면 박리모드가 고온/고습 처리 후 계면 근처 PI의 얕은 내부 박리 모드로 변경된 것으로 판단된다.

• 콘크리트학회논문집
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• 제29권4호
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• pp.407-413
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• 2017

본 연구는 콘크리트 보수재료로서의 MgO계 세라믹(Magnesia Phosphate Cement: MPC) 모르타르의 기초물성 평가를 위한 것이다. 이를 위해 응결시간, 압축강도, 부착강도를 측정하였으며 수화물의 측정을 위해 X-ray 회절분석을 실시하였다. 시편은 중질 마그네시아(dead burnt magnesia)를 바인더로 사용하였으며 활성제로 칼륨계 인산염을 사용하였고, 응결시간을 지연 시키기 위해 Borax를 지연제로 사용하였다. 또한, 이온침투저항성 평가를 위해 공극구조와 촉진염화물침투시험을 실시하였다. 그 결과 MPC 모르타르의 응결시간은 M/P 비에 따라 16~21분 사이로 빠르게 경화하였으며 지연제인 Borax는 MPC의 응결시간을 68분까지 늦추는 데 도움이 되었다. MPC 모르타르의 압축 강도는 12시간 재령에서 M/P 비에 따라 11.0~30.0 MPa 범위로 발현되었고 특히 M/P 비가 4인 MPC의 압축 강도는 12시간 이내에 30 MPa 정도의 강도를 발현하였다. MPC의 인장 부착강도와 휨 부착강도는 OPC 모르타르에 비해 각각 19 MPa와 17 MPa로 더 높게 측정되었으며 MPC 모르타르의 총 공극량은 OPC 모르타르에 비해 적게 측정되었고 촉진염화물침투시험에서도 MPC 모르타르를 통과한 총 전하가 OPC 모르타르보다 적었으며 이는 공극량과 공극분포로 설명 할 수 있다.

• 박물관보존과학
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• 제16권
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• pp.138-153
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• 2015

국립중앙박물관 소장 목제보살입상(본8239)은 조선총독부 박물관에서 중앙아시아유물을 수집하는 과정에서 구입한 것으로 전형적인 중국 송대(宋代) 양식을 갖추고 있으며 전체적으로 채색이 되어있다. 2014년 전시를 위하여 상태점검을 실시한 결과 채색안료의 변색과 박락, 목재의 갈라짐 등 손상이 심하여 보존처리를 실시하였다. 이와 함께 엑스선투과조사와 엑스선형광분석, 수종분석을 실시하여 제작기법과 재질을 확인하였다. 그 결과 보살입상은 여러 조각의 목재를 접합하여 제작한 것으로 확인되었고, 채색에 사용된 안료로 백색은 호분(CaCO₃)이나 석고(CaSO₄·2H₂O), 녹색은 양록(Cu(C₂H₃O₂)₂·3Cu(AsO₂)₂), 적색은 연단(Pb₃O₄), 청색은 울트라마린 블루(3Na₂O·3Al₂O₃·6SiO₂·2Na₂S)를 사용한 것으로 추정되며, 각 안료는 모두 후대에 다시 채색하면서 사용된 것으로 나타났다. 수종분석결과 제작과정에서 사용된 목재는 버드나무과의 사시나무류(Salicaceae Populus spp.)로 확인되었다. 목제보살입상은 천연재료를 사용하여 복원 및 강화처리를 하여 안정적인 상태가 되어 효과적인 전시가 가능하였다.

• Journal of Chest Surgery
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• 제13권1호
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• pp.60-65
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• 1980

We have experienced 2 cases of the hunshot wound sof the chest involving cardiac injuries at department of the thoracic surgery, Capital Armed Forces General Hospital during I year from April I 1979 to Jan. 1980. In one case of two patients , he was a 22 years old man who was transported to this emergency room 4 hour 10 minutes after having gunshot wound of the left chest by helicopter. Physical examination showed small inlet in left 3rd ICS and left parasternal border, large outlet in left 8th ICS and left scapular line, no breath sound on left side and distant heart sound. chest roentgenography demonstrated marked pleural effusion in left side and mediastinum shifted to right. As soon as chest X-ray was taken, the bleeding through penetrating wound became profuse and cardiac arrest ensued. Closed chest cardiac massage was started and vigorous transfusion continued, but no effective cardiac activity could not be obtained. The patient was pronounced dead due to exsanguinating hemorrhage from wuwpected cardiac wounds. In this critically injured patient with evidence of intrathoracic hemorrhage and suspected cardiac penetration, only emergency thoracic exploration and immediate surgical control of bleeding points might offer the maximum possibility of survival. The other case was a 23 years old man who was transferred to the emergency room 4 hours 50 minutes after having kmultiple communicated fractures of sternum and linear fracture of right mandible by a missile. Examination revealed about 30% skin loss of the anterior chest wall, weak pulse of 96 beats/min., distant heart sound and decreased breath sounds bilaterally. finding on the chest X-ray films showed multiple sternal fractures, marked pericardial effusion indicating hemopericardium. So, the patient was moved immediately to the operation room where, after endotracheal tube inserted, a median sternotomy was performced. A hemorrhagic congestion of the right upper lobe and marked bulging pericardium were disclosed. The pericardium was opened anterior to right phrenic nerve and exsanguinating hemorrhage ensued from the 0.5cm lacerated wound in the auricle of right atrium. The rupture site of right atrium was occluded with non-crushing vascular clamps and then was over sewn with interrupted sutures. It was thought to be highly possible that he was alive long enough to have cardiorrhaphy because of cardiac tamponade, which prevented exsanguinating hemorrhage. He was taken closed reduction for linear fracture of right mandible 2 weeks after repair of ruptured right auricle in dental clinic. This patient's post-operative course was not eventful.

• 한국응용과학기술학회지
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• 제31권3호
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• pp.478-485
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• 2014

이 연구는 경표피흡수를 위하여 큐빅액정의 자기조직체의 형성에 관한 것이다. 복수 수산기(-OH)를 가지는 친수부에 4개의 메칠 그룹을 가지는 양친매성지질인 diglyceryl phytylacetate (DGPA)를 합성하여 다양한 성능평가를 수행하였다. DGPA의 유화력은 1%의 적은 농도에서도 고 내상의 물을 함유하는 안정한 W/O water-in-oil)에멀젼이 유지되었다. DGPA, dimethicone (2CS), water의 3성분계의 특정영역에서, 안정한 큐빅상의 액정이 형성되었다. 3상 구조도 작성을 통하여 큐빅 액정영역, 헥사고날 영역, 물과 헥사고날이 혼제된 영역, 역미셀 영역을 확인하였고, SAXS (small angled x-ray scattering)분석을 통하여 그 구조를 증명하였다. 화장품의 응용으로, 큐보좀 (cubosome)에 10%의 마그네슘아스코르빌포스페이트, 5％의 피리독신트리헥사데카노에이트를 봉입하여 캡슐화하였다. 큐보좀의 occlusive 효과는 역미셀(reverse micelle)보다 1.7배 우수한 효과를 가졌다. 큐보좀을 분산제인 poloxamer를 사용하여 W/O 에멀젼을 만든 것으로부터 큐빅구조의 액정상으로 회복되는 것을 새롭게 발견하였다. 따라서, DGPA의 양친매성지질의 특성을 이용하여, 큐빅상의 액정을 형성하는 기재로써 화장품 산업과 의약품분야에서 경표피흡수제로써 응용이 가능할 것으로 기대된다.

• 한국건설순환자원학회논문집
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• 제11권1호
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• pp.89-96
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• 2023

산업부산물인 페로실리콘을 사용한 시멘트 콘크리트의 내구성능을 평가하기 위하여 페로실리콘의 치환율을 3단계로 변화시켜 제조한 시멘트 경화체의 염화물침투저항성, 알칼리실리카 반응성에 대하여 평가하였다. 페로실리콘을 사용한 시멘트 콘크리트의 내구성능은 화학조성이 유사한 실리카흄과 비교하여 평가하였으며, 에너지 분산형 X선 분광법, 공극측정 및 X선 회절분석 등 기기분석을 통하여 페로실리콘 콘크리트의 미세 구조적 특성을 고찰하였다. 그 결과, 페로실리콘을 10 % 치환한 경우 OPC콘크리트보다 높은 강도발현 특성을 보인 반면 치환율이 20 %, 30 % 증가할수록 압축강도는 낮게 발현되었다. 그러나 염화물 침투저항성에 대한 결과는 치환율이 증가할수록 우수한 결과를 나타내었으며, 실리카흄을 사용한 경우에 비하여 페로실리콘을 사용한 콘크리트의 내구성은 약간 떨어지지만 OPC에 비해서는 우수한 결과를 나타내었다. 이는 페로실리콘의 실리카(SiO₂) 함량이 높아 더 많은 C-S-H 겔을 생성하여 더 밀실한 공극 구조를 만들었기 때문이라 생각된다. 길이변화시험을 통한 규산염 바인더에 대한 알칼리실리카반응의 위험성은 대부분 0.2 % 미만으로 나타났으며, 페로실리콘 및 실리카흄을 사용한 모르타르 모두 치환율이 증가할수록 알칼리실리카 반응에 대한 저항성은 우수한 것으로 나타났다. 따라서 고가의 실리카흄을 사용하는 대신 산업 폐기물을 재사용하면 제조 중 환경 부하를 줄이고 비용을 절약할 수 있을 것으로 판단된다.

• 대한치과교정학회지
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• 제47권4호
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• pp.238-247
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• 2017

Objective: The aim of this study was to compare recycled and unused orthodontic miniscrews to determine the feasibility of reuse. The comparisons included both miniscrews with machined surfaces (MS), and those with etched surfaces (ES). Methods: Retrieved MS and ES were further divided into three subgroups according to the assigned recycling procedure: group A, air-water spray; group B, mechanical cleaning; and group C, mechanical and chemical cleaning. Unused screws were used as controls. Scanning electron microscopy, energy-dispersive X-ray spectrometry, insertion time and maximum insertion torque measurements in artificial bone, and biological responses in the form of periotest values (PTV), bone-implant contact ratio (BIC), and bone volume ratio (BV) were assessed. Results: Morphological changes after recycling mainly occurred at the screw tip, and the cortical bone penetration success rate of recycled screws was lower than that of unused screws. Retrieved ES needed more thorough cleaning than retrieved MS to produce a surface composition similar to that of unused screws. There were no significant differences in PTV or BIC between recycled and unused screws, while the BV of the former was significantly lower than that of the latter (p < 0.05). Conclusions: These results indicate that reuse of recycled orthodontic miniscrews may not be feasible from the biomechanical aspect.

• 한국응용과학기술학회지
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• 제30권2호
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• pp.215-224
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• 2013

Recently, many cosmetic researchers have been focused on the development of high functional cosmetics including anti-wrinkle and whitening. In these studies, they couldn't afford to pay a deep attention to stable encapsulations for unstable materials and efficient drug deliveries for them. Particularly, in order to show a degree of instant effects as cosmetics, they can't also ignore moisturizing effect enough to satisfy customers just after applying and its maintenance by improving the function of skin barrier as well as above two effects. Therefore, skin analogue systems have attracted considerable attention in the view of structural and compositional similarity to intercellular membrane in stratum corneum. And, some models for skin analogue composition were developed to improve the function of skin barrier, stably encapsulate unstable materials such as retinol, vitamin B, C, E, etc., and control their skin penetration in order to show good effects as cosmetics. In this study, we suggest the new skin analogue model having the compositional similarity as well as conventional structural ones. Our skin analogue membrane(SAM) is mainly composed of ceramide/ cholesterol/phosphatidylcholin/fatty acids and its structural defects are compensated by including cholesterol amphiphile and controlling the ratio of ceramide/cholesterol. It was possible to confirm the formation of skin analogue membrane having highly-densed multilamella structure and compare them according to the change of each ratio with a polarized microscope, X-ray diffraction. More detaily, we observed their structures with a electron microscope(TEM). Finally, we dispersed them in excess of continuous water phase, observed the formation of maltese-cross liquid crystalline and measured the efficiency of drug deliveries and moisturizing effects.

• Macromolecular Research
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• 제11권3호
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• pp.183-188
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• 2003

The controlled delivery of anticancer agents using biodegradable polymeric implant has been developed to solve the problem of penetration of blood brain barrier and severe systemic toxicity. This study was performed to prepare 5-FU-loaded poly (L-lactide-co-glycolide) (PLGA) wafer fabricated microparticles prepared by two different method and to evaluate their release profile for the application of the treatment of brain tumor. 5-FU-loaded PLGA microparticles were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and differential scanning calorimetry (DSC). SEM observation of the 5-FU-loaded PLGA microparticles prepared by rotary solvent evaporation method showed that 5-FU was almost surrounded by PLGA and significant reduction of crystallinity of 5-FU was confirmed by XRD. In case of release profile of 5-FU from 5-FU-loaded PLGA wafer fabricated microparticles prepared by mechanical mixing, the release profile of 5-FU followed near first order release kinetics. In contrast to the above result, release profile of 5-FU from 5-FU-loaded PLGA wafer fabricated microparticles prepared by rotary solvent evaporation method followed near zero order release kinetics. These results indicate that preparation method of the 5-FU-loaded PLGA microparticles to fabricate into wafers was contributed to drug release profile.

• 한국분말재료학회지
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• 제22권4호
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• pp.234-239
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• 2015

Electronic products are a major part of evolving industry and human life style; however most of them are known to emit electromagnetic waves that have severe health hazards. Therefore, different materials and fabrication techniques are understudy to control or limit transfer of such waves to human body. In this study, nanocomposite powder is dispersed into epoxy resin and shielding effects such as absorption, reflection, penetration and multiple reflections are investigated. In addition, nano size powder (Ni, $Fe_2O_3$, Fe-85Ni, C-Ni) is fabricated by pulsed wire evaporation method and dispersed manually into epoxy. Characterization techniques such as X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy are used to investigate the phase analysis, size and shape as well as dispersion trend of a nano powder on epoxy matrix. Shielding effect is measured by standard test method to investigate the electromagnetic shielding effectiveness of planar materials, ASTM D4935. At lower frequency, sample consisting nano-powder of Fe-85%Wt Ni shows better electromagnetic shielding effect compared to only epoxy, only Ni, $Fe_2O_3$ and C-Ni samples.