• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.393-393
• /
• 2012

Optically active nanostructures such as subwavelength moth-eye antireflective structures or surface enhanced Raman spectroscopy (SERS) active structures have been demonstrated to provide the effective suppression of unwanted reflections as in subwavelength structure (SWS) or effective enhancement of selective signals as in SERS. While various nanopatterning techniques such as photolithography, electron-beam lithography, wafer level nanoimprinting lithography, and interference lithography can be employed to fabricate these nanostructures, roll-to-roll (R2R) nanoimprinting is gaining interests due to its low cost, continuous, and scalable process. R2R nanoimprinting requires a master to produce a stamp that can be wrapped around a quartz roller for repeated nanoimprinting process. Among many possibilities, two different types of mask can be employed to fabricate optically active nanostructures. One is self-assembled Au nanoparticles on Si substrate by depositing Au film with sputtering followed by annealing process. The other is monolayer silica particles dissolved in ethanol spread on the wafer by spin-coating method. The process is optimized by considering the density of Au and silica nano particles, depth and shape of the patterns. The depth of the pattern can be controlled with dry etch process using reactive ion etching (RIE) with the mixture of SF6 and CHF3. The resultant nanostructures are characterized for their reflectance using UV-Vis-NIR spectrophotometer (Agilent technology, Cary 5000) and for surface morphology using scanning electron microscope (SEM, JEOL JSM-7100F). Once optimized, these optically active nanostructures can be used to replicate with roll-to-roll process or soft lithography for various applications including displays, solar cells, and biosensors.

• Investigative Magnetic Resonance Imaging
• /
• 제21권3호
• /
• pp.177-182
• /
• 2017

Schwannomas are benign nerve sheath tumors that are typically located in soft tissue. Occasionally, schwannomas involve osseous structures. These intraosseous schwannomas are generally benign neoplasms that account for less than 0.2% of primary bone tumors. Schwannomas are very rarely observed in long bones. We present a case of a schwannoma affecting the proximal femur with a coincident subchondral fracture of the femoral head. A 38-year-old-male presented with left hip pain without deteriorating locomotor function. Plain film radiographs displayed a lobulating contoured lesion within the intertrochanteric portion of the femur. The magnetic resonance imaging (MRI) scans showed a tumor occupying the intertrochanteric region. Diffuse bone marrow edema, especially in the subchondral and head portions of the femur that was possibly due to the subchondral insufficiency fracture was also noted. The lesion was surgically excised and bone grafting was performed. Histologically, there was diffuse infiltrative growth of the elongated, wavy, and tapered cells with collagen fibers, which are findings that are characteristic of intraosseous schwannoma. Although very rare, intraosseous schwannoma should be included in the differential diagnosis of radiographically benign-appearing, non-aggressive lesions arising in the femur. The concomitant subchondral fracture of the femoral head confounded the correct diagnosis of intraosseous schwannoma in this case.

• Journal of Korean Neurosurgical Society
• /
• 제29권11호
• /
• pp.1484-1490
• /
• 2000

Objectives : In spinal metastasis and myeloma, percutaneous vertebroplasty could be an effective treatment method to provide spinal stabilization and to relief pain for early rehabilitation. The authors report twenty-five cases the clinical results of percutaneous vertebroplasty for twenty-five cases of spinal metastasis and myeloma. Materials and Methods : From September 1998 to December 1999, seventy percutaneous vertebroplasties(PVP) were performed for spinal metastases and myeloma in 25 patients, sixteen women and nine men ranging in age from 34 to 74. The primary malignancies were 6 multiple myelomas, and in metastatic tumore from various origin. All patients complained of severe pain and had osteolytic vertebral body destructions without spinal cord compression. To evaluate clinical improvement, suObjective verbal analogue pain score(VAS) and Karnofsky performance scale(KPS) were used. Thin sliced(2mm-thickness) sectional computed tomography(CT) was performed before and after PVP. Plain X-ray film was followed up every 1 month to assess the vertebral column stability. Results : In 25 patients, a total of seventy PVPS were performed successfully : 6 cervical, 33 thoracic and 31 lumbar vertebrae. Most patients had clear improvement of pain after PVP ; mean as score was 8.1 and 2.9 before and after PVP, respectively. Improvement was maintained in most patients. No further collapse of treated vertebrae was observed(mean follow-up, 7 months). Leakage of PMMA was notod in the spinal canal(13 levels), neural foramen (2 levels), adjacent disk(15 levels), paravertebral soft tissue(14 levels) and vein(8 levels). Pulmonary embolism was detected in three patients after the procedure, but was not associated with clinical symptoms. Conclusion : These results indicate that percutaneous vertebroplasty can be valuable treatment method in osteolytic spinal metastasis and myeloma, providing immediate pain relief and spinal stabilization and contributing to early rehabilitation.

• 공학교육연구
• /
• 제7권3호
• /
• pp.44-50
• /
• 2004

수강자의 전공에 상관없이 어렵고 다양한 공학의 문제들을 쉽게 접근하도록 하는 강의를 소개한다. 이 강의는 공학에 대한 사전지식이나 경험을 요구하지 않는다. 반면에 기술과 동떨어져 생각할 수 없는 일상생활의 현재와 미래의 모습에 대한 강한 호기심과 상상력만을 수강자에게 요구한다. 강의를 통하여 바람직한 공학과 공학행위란 무엇인가 하는 공학의 기본적인 문제제기에 대해 수강자들이 고민해 볼 수 있도록 유도한다. 강의 주제가 공학의 다양한 면을 다루기 때문에 기존의 학습 방법은 효과적이거나 성공적이지 못하다. 이에 대한 대안으로 강의에서는 모의적인 사유실험과 물리적인 미디어 체험 등을 이용한 효과적인 학습법을 사용하였다. 선정된 공학적 주제에 따라 씌어진 시나리오를 구성하고 이 시나리오에 따라 짧은 영화 형식의 약 20개의 강의 컨텐츠를 만든다. 제작된 영상을 보면서 수강자들과 토론을 나누었다. 수강자의 흥미 유도를 위하여 로봇과 같은 미디어가 사용되었다. 온라인과 오프라인에서의 강의자와 수강자 사이의 인터액션 유도, 공학적 주제에 대한 적극적인 의견 개진을 유도하는 과제 수행, 강의 주제에 관련된 영상 제작 프로젝트 수행 및 평가 등 인터액티브한 공학개론 교육 사례로 부산대학교에서 시행된 지능공학 강의 경험을 소개한다.

• Tuberculosis and Respiratory Diseases
• /
• 제38권3호
• /
• pp.309-316
• /
• 1991

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of late adult life. This tumor occurs principally as a mass on an extremity or in the abdominal cavity or retroperitoneum of adult but primary pulmonary MFH is rare. MFH may be subclassified into storiform-pleomorphic, myxoid, giant cell, inflammatory, and angiomatoid type and the prognosis is no different among the histologic subtypes. We experienced one patient who was consistent with primary MFH of the lung. The patient complained dyspnea and intermittent hemoptysis and showed bilateral suprahilar mass on simple chest film and chest CT. Histological findings by open lung biopsy was storiform-pleomorphic type and individual cells showed histiocyte-like and fibroblast-like appearance.

• Journal of Yeungnam Medical Science
• /
• 제17권2호
• /
• pp.123-128
• /
• 2000

본 연구에서 인체공학적으로 개선된 새로운 2-채널 고선량을 근접치료용 적용구(Shin's Applicator)를 개발하였으며, 기존의 단일 선원 근접치료 적용구와 비교하여 질벽에 더 균등한 방사선치료가 가능하고 방광과 직장선량이 적어 근접치료 후 발생할 수 있는 부작용이 감소될 가능성을 확인하였다. 임상적으로 Shin's Applicator는 자궁 경부암이나 자궁 체부암의 수술 후 국소재발이나, 절강에 발생한 다발설 악성종양을 효과적으로 치료하는 데 유용하게 사용될 수 있을 뿐 만 아니라, 방사선 치료 후 흔히 나타나는 질강의 협착을 예방할 수 있는 질 확장기(vaginal dilator)로도 사용 가능하였다. 이상의 결과에서 Shin's Applicator는 부인과 종양환자들의 방사선치료 뿐만 아니라 치료 후 삶의 질의 개선에도 크게 기여할 것으로 생각되었다.

• 한국전기전자재료학회논문지
• /
• 제29권10호
• /
• pp.601-607
• /
• 2016

Piezoelectric thick films of soft $Pb(Zr,Ti)O_3$ (PZT) based commercial material (S55) were fabricated using a conventional tape casting method. Ag-Pd electrodes were printed on the piezoelectric film at room temperature and all 5 layered films with a dimension of $12mm{\times}16mm$ were successfully laminated for a multi-layered piezoelectric ceramic actuator. The laminated specimens were co-fired at $1,100^{\circ}C$ for 1 h. A flat layered and dense microstructure was obtained for the $112{\mu}m$ thick piezoelectric actuator after sintering process. Thereafter, a prototype piezoelectric speaker was fabricated using the multi-layered piezoelectric ceramic actuator which can operate as a bimorph. Its SPL (sound pressure level) characteristic was also evaluated for speaker application. Frequency response revealed that the output SPL with a root mean square voltage of 10 V increased gradually to the highest peak of 87.5 dB for 1.5 kHz and exhibited a relatively stable behavior over the measured frequency range (${\leq}20kHz$) at a distance of 10 cm, implying that the fabricated piezoelectric speaker is potential for speaker applications.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.396-396
• /
• 2013

The resistive random access memory (ReRAM) has several advantages to apply next generation non-volatile memory device, because of fast switching time, long retentions, and large memory windows. The high mobility of monolayered graphene showed several possibilities for scale down and electrical property enhancement of memory device. In this study, the monolayered graphene grown by chemical vapor deposition was transferred to $SiO_2$ (100 nm)/Si substrate and glass by using PMMA coating method. For formation of metal-oxide nanoparticles, we used a chemical reaction between metal films and polyamic acid layer. The 50-nm thick BPDA-PDA polyamic acid layer was coated on the graphene layer. Through soft baking at $125^{\circ}C$ or 30 min, solvent in polyimide layer was removed. Then, 5-nm-thick indium layer was deposited by using thermal evaporator at room temperature. And then, the second polyimide layer was coated on the indium thin film. After remove solvent and open bottom graphene layer, the samples were annealed at $400^{\circ}C$ or 1 hr by using furnace in $N_2$ ambient. The average diameter and density of nanoparticle were depending on annealing temperature and times. During annealing process, the metal and oxygen ions combined to create $In_2O_3$ nanoparticle in the polyimide layer. The electrical properties of $In_2O_3$ nanoparticle ReRAM such as current-voltage curve, operation speed and retention discussed for applictions of transparent and flexible hybrid ReRAM device.

• 한국공간구조학회논문집
• /
• 제7권2호
• /
• pp.115-124
• /
• 2007

막 구조물을 설계하기 위해서는 우선 초기장력 도입으로 인한 구조물의 형상을 정확히 알아야 한다. 이를 위해서 모형을 통한 모델링이나 컴퓨터를 이용한 형상해석이 요구되며, 초기장력의 도입으로 형성되는 막 구조물의 곡면은 일반적으로 등장력 곡면이다. 이와 같은 특성을 가진 막 구조물은 모형만을 대상으로 형상을 구할 때에는 정량적으로 형상의 정보를 얻기가 힘들고, 형상해석만을 수행한 경우는 예기치 않은 문제가 발생하기도 한다. 또 설계자의 의도에 따른 형상은 실질적으로 등장력 곡면에 부합되지 않는 경우가 많고, 심지어 실현 불가능한 발생한다. 따라서 설계프로세스에 따른 구조물의 형상에 부합되면서 실현가능한 형상으로의 초기형상 결정과정은 막 구조물의 설계에 있어서 무엇보다 중요한 과정이다. 본 연구에서는 건축 설계프로세스에 따른 모델링과 수치적 형상해석과의 결과에 대한 차이를 살펴보고 피드벡 과정을 통하여 막 구조물의 초기형상을 결정하는 프로세스에 대해서 연구한다.

• 한국광학회지
• /
• 제18권2호
• /
• pp.149-154
• /
• 2007

저가의 소자 개발이 가능한 나노임프린팅 공정을 도입하여 510 nm 주기의 브래그 격자 구조를 가지는 폴리머 광도파로 소자를 제작하였다. 폴리머 격자 광소자의 온도 의존성을 감소시키기 위한 방법으로 플라스틱 박막으로 이루어진 유연성 기판상에 브래그 격자를 제작하는 것이 필요하다. 임프린팅 공정을 손쉽게 수행하기 위한 광도파로 구조를 채택하였으며, 코아와 클래딩의 굴절률이 각각 1.540, 1.430인 폴리머를 이용하여 코아 두께가 $3{\mu}m$인 단일모드 광도파로 구조를 얻을 수 있었다. 유연성 기판 브래그 격자 광도파로 소자의 특성을 Si기판 브래그 격자 광도파로 소자와 비교하여 관측한 결과, 유연성 기판 도입에 따른 브래그 반사 소자의 성능 저하는 나타나지 않았다.