• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.95-95
• /
• 2012

스터퍼링 기술이 1852년 Grove에 의해서 최초 발견되어 1979년 Chapin에 의해서 planar magnetron cathode 개발로 진공코팅기술의 새로운 영역을 열게 되어 현재까지 디스플레이, 반도체, 태양전지, 광학산업 및 전자부품 등 나노 산업에 필수적으로 적용되고 있다. 스퍼터링 입자는 운동량 전달에 의한 것으로 운동량을 갖는 나노 스퍼터링 입자는 기판에 대한 박막의 부착력이 우수하고 대면적에 균일하고 재현성 있게 성막되는 특징을 갖고 있다. 마그네트론 스퍼터링 기술이 산업에 응용되면서 주로 4분야에서 많은 연구, 개발이 되어져 왔다. 첫째는 타겟의 고순도 및 고밀도화와 더불어 가격이 고가로 됨에 따라 타겟 사용효율의 향상이다. 플라즈마를 발생시키는 캐소드의 자기회로를 1차원, 2차원 및 회전운동을 통해서 사용효율을 향상시키고 있다. 둘째는 기판에 대해서 박막특성이 균일하도록 코팅하는 것이다. 디스플레이에서는 글래스 기판이 대면적으로 됨에 따라서 핸들링이 어려워져 여러 개의 캐소드 자기회로를 선형적으로 이동시켜 박막두께분포를 최적화하며 반응성 가스를 사용해서 균일한 특성의 박막을 제작하는 경우에는 가스분사관과 배기펌프계의 기하학적 위치 및 가스 유동학적 해석이 필요하다. 셋째는 스퍼터링 입자의 이온화로 의한 박막의 특성향상과 반도체 trench의 높은 aspect ratio hole을 채우는 것이다. 이온화 방법으로는 inductively coupled plasma (ICP), microwave amplified (MA), high power impulse (HIPI), hollow cathode magnetron (HCM), self-sustained sputtering 등이 사용되어져 왔으며 최근에는(neutral beam-assisted sputtering (NBAS)에 의한 박막특성향상 방법이 발표되고 있다. 넷째는 플라즈마 및 박막두께 시뮬레이션에 대해서 많은 발표가 되고 있다. 본 발표에서는 상기의 4 분야를 포함한 향후 개발방향에 대해서 소개할 예정이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.781-783
• /
• 2010

Chonbuk national university High-enthalpy plasma research center is under construction for 60kW and 200kw ICP(RF) Plasma system as Advance Material R&D and production equipment. The 60kW & 200kW ICP(RF) plasma systems will contribute to promote Korea's material industrial development and Thermal plasma technology.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.05a
• /
• pp.38.2-38.2
• /
• 2009

마이크로노즐은 우주공간에서 인공위성의 자세를 바로잡는 데 필요한 마이크로 로켓에 들어가는 필수적인 부품이다. 마이크로 노즐은 또한 나노입자 적층 시스템(nano-particle deposition system, NPDS)에 들어갈 수 있다. NPDS는 세라믹 또는 금속 나노분말 입자를 노즐을 통해 초음속으로 가속시킨 뒤 상온에서 이를 기판에 적층시키는 새로운 시스템이다. 본 연구의 목표는 NPDS에 쓰이는 노즐을 일반적인 반도체 공정을 이용하여 마이크론 스케일의 목을 갖도록 한 마이크로노즐을 제작하는 데 있다. 보쉬 공정은 이러한 마이크로노즐을 제작하는데 필수적인 공정으로, 유도결합플라즈마를 이용해 실리콘 웨이퍼를 식각시키는 기술을 말한다. 보쉬 공정에 사용되는 플라즈마 기체는 $SF_6$와 $C_4F_8$인데, 이 두 가지 기체를 번갈아가면서 사용하여 실리콘 웨이퍼를 이방성 식각하는 것이 그 특징이다. 보쉬 공정에는 다양한 변수가 존재하며 이를 적절히 통제하면 마이크로노즐에 적합한 프로파일을 실리콘 웨이퍼 내에 형성시킬 수 있다. 본 연구에서는 보쉬 공정을 이용하여 3차원 마이크로 노즐을 제작하였다. 기존에 반응성이온식각(deep reactive ion etching, DRIE) 공정을 통해 마이크로노즐을 제작한 사례가 많이 보고되었지만 이들은 모두 2차원적으로 마이크로노즐을 제작하였다. 2차원적으로 제작한 마이크로노즐은 마이크로 로켓에 주로 사용되었지만, 초음속으로 가속된 분말이 노즐의 형상으로 인한 유체 흐름의 불안정성 때문에 NPDS에서는 오래도록 사용할 수 없다는 문제점이 있다. 그러므로 본 연구에서는 마이크로노즐을 3차원 형상으로 제작함으로써 이러한 문제점을 해결하고자 하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.220-223
• /
• 2005

The rapid prototyping (RP) technology has been advanced for various applications such as verification of design, functional test. However, many RP machines still have low accuracy and limitation of applications for various materials. In this research, a hybrid RP system was developed to improve precision of micro parts. This hybrid system consists of deposition and material removal process by mechanical micro machining to fabricate nano composites using photo-curable polymer resin with various nano particles. In this work, using hybrid RP process with Multi-Walled Carbon Nano Tube (MWCNT) and hydroxyapatite, micro parts were fabricated. The precision of parts was evaluated based on the original CAD design, and to see the effect of nano particles on mechanical properties, tensile strength was measured. From the results of experiments, it was confirmed that the part made by hybrid process had higher precision, and the addition of nano particles improved mechanical properties.

• Korean Journal of Optics and Photonics
• /
• v.32 no.6
• /
• pp.266-275
• /
• 2021

In this paper, a method for evaluating optical-system performance and an athermal structure through thermal analysis of the Korsch telescope was studied. In the case of an optical system having a complex asymmetrical structure, there is a limit to implementing the satellite structure by applying the coefficient of thermal expansion (CTE) in the optical-design software, so it is difficult to evaluate the performance of the optical system against temperature changes. To solve this problem, using mechanical design software all length changes were implemented in all structures that affect the optical system according to temperature, and the value of the change in distance between optical components due to temperature change was organized. Also, the values of changes in shape and thickness of the optical components against temperature changes are organized in the optical-design software. All changes derived from both software packages were applied in the optical software to evaluate the performance of the optical system. As a result, it was found that the MTF for a spatial resolution of 71.4 cycles/mm was maintained at more than 25% in the range from 9 ℃ to 33 ℃. In addition, the performance of the optical system applying the improved structure was evaluated, by finding the structure that had the most influence on the optical system's performance change, and deriving an athermal structure to reduce the effect. As a result, it was found that the MTF for a resolution of 71.4 cycles/mm was maintained at over 67% in the range from 9 ℃ to 33 ℃.

• Journal of Korea Foundry Society
• /
• v.44 no.1
• /
• pp.9-15
• /
• 2024

In this study, in order to improve the lifespan of parts made of manganese steel, manganese steel was cast by varying the amount of Ti added to the steel. In order to confirm the characteristics of the cast material, processing characteristics including tensile and surface characteristics and bearing ratio were investigated. It was confirmed that when the amount of Ti added to high manganese steel exceeds 0.5%, the strength of the alloy is improved due to grain refinement, and fine carbides are formed inside the steel. This results in increased resistance to surface wear compared to the alloy with only Mn added. There was no significant difference in the increase in tensile strength as the Ti content in manganese steel was increased. However, inclusion of Ti showed a small but greater effect on wear resistance compared to Mn, and the size and the distribution of carbides become coarse depending on the Ti content. and was evenly distributed. It was confirmed that the strength and surface properties of manganese steel can be improved by the addition of Ti to improve the lifespan of parts made with this steel. It was found that Ti is effective in developing materials with excellent wear resistance due to refinement of dendrite crystal grains. In the samples where Ti was added, the carbide appears to increase the resistance to surface roughness, and due to the nature of Mn steel, surface hardening begins to occur, which appears to extend the life.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.3
• /
• pp.619-626
• /
• 2019

The advances of semiconductor and circuitry technology dovetailed with nano processing techniques have further enhanced micro-miniaturization, sensitivity, longevity and reliability in MID(Medical Implant Device). Nevertheless, one of the remaining challenges is whether power can sufficiently and continuously be supplied for the operation of the MID. Self-powered MID that harvest biomechanical energy from human motion, respiratory and muscle movement are part of a paradigm shift. In this paper, we developed a rechargeable pacemaker through self-power generation with the triboelectric nanogenerator. We demonstrate a fully implanted pacemaker based on an implantable triboelectric nanogenerator, which act as a storage as well as active movement on a large-animal(dog) scale. The self-power pacemaker harvested from animal motion is 2.47V, which is higher than the required pacemaker device sensing voltage(1.35V).

• Journal of Energy Engineering
• /
• v.24 no.4
• /
• pp.124-129
• /
• 2015

An experimental study was performed estimating COP(Coefficient of Performance) of air-conditioning cycle using inverter scroll compressor with and without $Al_2O_3$ nano particle. All experiments were done for various compressor speeds from 1000~4000 rpm and used the inverter controller called CANDY to change the compressor rpm. The air-conditioning cycle components in the apparatus were used as same with components of YF hybrid car. To estimate the COP, this study measured the temperature and pressure at inlets and outlets of compressor, condenser, and evaporator. And also measured the compressor input power using Powermeter. Through the experiments, the maximum error to estimate COP was shown about ${\pm}6.09%$ at 3500rpm. The COP of refrigeration cycle with $Al_2O_3$ nano-particle was similar with that of the base cycle without nano-particle between 1000~3000 rpm of the compressor speed. But, This study showed that the COP of the cycle with $Al_2O_3$ over 3000 rpm of the compressor speed was higher than that of the base cycle due to the higher heat transfer rate increased in the evaporator from the higher oil flow rate inside the cycle as well known. Those results can be used the basic and fundamental data to design the air-conditioning cycle using inverter scroll compressor with $Al_2O_3$ nano particle.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.11-18
• /
• 2021

Nano bubble water is used in various washing processes, including cleaning of solar panels, salt rejection of roads, and cleaning precision parts of machines. High cleaning efficiency and water conservation are obtained by applying nano bubbles during pretreatment of the marine waste cleaning system. This study compared the salt rejection of nano bubble water, and it was revealed that marine waste was produced by wood immersed in 200,000 mg/L NaCl solution. Using tap water and nano bubble water for washing, comparisons of the surface salt concentrations of wood were determined according to the nozzle, orifice diameter, pump speed and washing time. Decreased surface salt concentration was observed on the wood surface with increasing washing time. Water consumption was optimal between 5- and 10-seconds washing time. Increasing orifice diameter of the nozzle reduced the spraying pressure, with consequent increase in the wood surface salt concentration, thereby establishing the importance of orifice diameter of the nozzle. Compared to levels obtained with tap water, salt concentration of the wood surface after washing with nano bubble water was 2.2% lower with sector nozzle, and 30.9% lower with circular nozzle. In the washing experiment using nano bubble water, the salt concentration on the wood surface was about 9.5 mg/L lower when washed with sector nozzle than the circular nozzle.

• Applied Chemistry for Engineering
• /
• v.21 no.5
• /
• pp.564-569
• /
• 2010

Highly anti-reflective optical property has been focussed in the field of thin film and display because of increasing demands to the high transparency and clearness of optical component. In this study, to obtain anti-reflective property, the formation of aluminium oxide with nanoscaled flowerlike frame structure was introduced as oxide material monolayer on the substrate by hydrothermal synthesis through sol-gel method. The properties of coating layer were measured by the means of UV-Vis spectroscopy, FT-IR spectroscopy, XRD, and FE-SEM. The morphology of coating layer in alumina-sol coated samples was controlled by hydrothermal temperature and time with aid of ultrasound. It was found that high transparency and anti-reflective optical properties were obtained the formation of flowerlike nanoframe structure.