• Title/Summary/Keyword: micro/nano disk

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Development of Nipkow Disk for High-Speed Confocal Probe Using Micro-lens and Pinhole Disks (마이크로 렌즈 디스크와 핀홀 디스크를 이용한 고속 공초점용 닙코 디스크 개발)

  • Kim, Gee Hong;Lee, Hyung Seok;Kim, Chang Kyu;Lim, Hyung Jun;Lee, Jae Jong;Choi, Kee Bong
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.6
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    • pp.636-641
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    • 2014
  • This paper discusses the fabrication process for a Nipkow disk using micro-lens and pinhole disks. The confocal measuring system that uses the Nipkow disk has the advantage in measuring speed, because the Nipkow disk can simultaneously provide confocal images of all pixels in a CCD camera without requiring a lateral scanning unit. A micro-lens configuration, which focuses illumination on a pinhole, overcomes the low optical efficiency of the Nipkow disk system and allows its use in practical applications. This paper describes how to design the Nipkow disk in terms of numerical aperture, particularly for measuring the height of solder bumps in packaging application and for hybrid processes combining mechanical and semiconductor processes.

A Study on the Precision Processing of Thin Stamper with Global Area (대면적 박판 스탬퍼 정밀 가공을 위한 연구)

  • 최두선;제태진;서승호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.632-635
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    • 2003
  • As a process technology of nano pattern with a new conception for economic and practical technology of alternative nano process. process technologies such as Embossing, Imprinting. Molding and Inking are beginning to make its appearance. Among these alternative processes, nano mold process is a process that is of benefit to mass production and keeps excellency of reproduction and high quality of parts. In this study, we experienced micro precision machining technology of nano stamper for the injection mold of optical disk with big capacity. Especially, Flatness and uniformity are important for nano stamper with global area, for the purpose of developing polishing technology of micro precision of Back polishing only being used for nano stamper, we carried out a basic study to secure flatness standards

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Investigation of Head-Disk Impact for Development of Ultra-Low Flying HDI (극저부상 HDI 개발을 위한 Head-Disk Impact 연구)

  • 조언정;박노열
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.122-126
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    • 2001
  • Magnetic hard disk drive is continually being pushed to reduce head-disk spacing for higher recording densities. The current minimum spacing between the air-bearing slider and disk has been reduced to under 15 nm. In this work, it was investigated if flying height could be lowered under the height of laser bumps. With the reduction of the spinning speed, the flying height was decreased under the height of laser bumps. When a head swept between landing zone and data zone, the head-disk impact was monitored using AE and friction signals. It is demonstrated that magnetic hard disk drive could be operated without tribological failures under the height of laser bumps.

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A Study on Head-Disk Interactions at Ultra-low Flying Height in Contact Start-Stop (Contact Start-Stop 방식에서의 극저부상 높이에서 Head-Disk Interface Interactions 연구)

  • 조언정
    • Tribology and Lubricants
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    • v.19 no.2
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    • pp.102-108
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    • 2003
  • The height of laser bumps has been considered as the limit of the minimum flying height in the contact start-stop (CSS) of hard disk drives. In this paper, tribological interactions at flying height under laser bumps are investigated in a spin stand for development of ultra-low flying head-disk interface. With the reduction of the spinning speed in a spin stand, the flying height is decreased under the height of laser bumps and, then, head-disk interactions are investigated using AE and stiction/friction signals. During seek tests and 20000 cycle-sweep tests, AE and stiction/friction signals are not significantly changed and there are no catastrophic failures of head-disk interface. Bearing analysis and AFM analysis show that there are signs of wear and plastic deformation on the disks. It is suggested that flying height could be as low as and, sometimes, lower than laser bump height.

Management of the energy harvesting for MEMS/NEMS via newmark current method

  • Shang, Kun;Shan, Huafeng;Alkhalaf, Salem;Marzouki, Riadh;Khadimallah, Mohamed Amine
    • Advances in nano research
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    • v.12 no.6
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    • pp.567-581
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    • 2022
  • The free and forced vibration in addition to electric energy harvesting of a piezoelectric disk resting on two-parameter foundation modeled by modified couple stress as well as Kirchhoff plate theory is probed. The governing equations and boundary conditions are obtained using Hamilton's principle. Then, the free and forced vibration are solved using numerical solutions, generalized differential quadrature method (GDQM) and Newmark-beta method. The forced vibration is resulted from a base excitation load. Also, the possible voltage which can be harvested from this system is obtained using generalized integral quadrature method. The validity of the formulation and solution procedure is confirmed using a compassion study. The impact of parameters such as length effect, inner to outer radius ratio, and foundations parameters on the free and forced vibration as well as energy harvesting is investigated in detail. This paper can be a basis for future studies in the area of piezoelectric harvesters in small scales.

Preparation of Poly(vinyl alcohol)/polypropylene Nano-filter by High Speed Centrifugal Solution Spinning (초고속 용액 원심방사를 이용한 폴리비닐알코올/폴리프로필렌 나노필터 제조)

  • Yang, Seong Baek;Lee, Jungeon;Park, Jae Min;Jung, Jae Hoon;Kim, Tae Young;Kim, Ki Young;Lee, Sang Jun;Yeum, Jeong Hyun
    • Textile Coloration and Finishing
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    • v.34 no.1
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    • pp.20-26
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    • 2022
  • Centrifugal spinning is an emerging technique for fabricating micro-to-nano-fibers in recent years. To obtain fibers with the desired size and morphology, it is necessary to configure and optimize the parameters used in centrifugal spinning. In this study, it was controlled by changing the solution's concentration (7.5, 10, and 12.5 wt.%) and disk's rotational velocity (6,000, 8,000, and 10,000 rpm) to prepare centrifugal spun nano-filter. The morphological property, air permeability, and dust collection efficiency of the PVA/PP bi-layer nanoweb prepared by centrifugal spun PVA on the PP micron nonwoven substrate are studied using a field emission scanning electron microscope, an air permeability tester, and a filter tester equipment, and the analysis results indicate that it is suitable as a nano-filter when the concentration of PVA solution is 10 wt.% and the rotational velocity of the disk is 8,000 rpm. The resultant reduced diameter and uniform fibers also proved that an excellent dust collection efficiency filter could be made.

Small Molecular Solar Cells toward Improved Efficiency and Stability

  • Kim, Ji-Hwan;Kim, Hyo-Jeong;Jeong, Won-Ik;Kim, Tae-Min;Lee, Yeong-Eun;Kim, Se-Yong;Kim, Jang-Ju
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.73-73
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    • 2011
  • We will report a few methods to improve the efficiency and stability in small molecule based organic solar cells, including the formation of bulk heterojunctions (BHJs) through alternative thermal deposition (ATD), the use of a micro-cavity structure and interface modifications. By ATD which is a simple modification of conventional thermal evaporation, the thicknesses of alternative donor and acceptor layers were precisely controlled down to 0.1 nm, which is critical to form BHJs. The formation of a BHJ in copper(II) phthalocyanine (CuPc) and fullerene (C60) systems was confirmed by AFM, GISAXS and absorption measurements. From analysis of the data, we found that the CuPc|C60 films fabricated by ATD were composed of the nanometer sized disk shaped CuPc nano grains and aggregated C60, which explains the phase separation of CuPc and C60. On the other hand, the co-deposited CuPc:C60 films did not show the existence of separated CuPc nano grains in the CuPc:C60 matrix. The OPV cells fabricated using the ATD method showed significantly enhanced power conversion efficiency compared to the co-deposited OPV cells under a same composition [1]. We will also present by numerical simulation that adoption of microcavity structure in the planar heterojunction can improve the short circuit current in single and tandem OSCs [2]. Interface modifications also allowed us to achieve high efficiency and high stability OSCs.

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Fabrication of Porous Cellulose Acetate Propionate/Polybutylene Succinate Microfibers by High Speed Centrifugal Spinning (초고속 원심방사에 의한 아세트산프로피온산 셀룰로오스/폴리부틸렌 숙시네이트 다공성 마이크론 섬유 제조)

  • Tae Young Kim;Mi Kyung Kim;Jinsoo Kim;Jungeon Lee;Jae Hoon Jung;Youngkwon Kim;Tae Hyeon Kim;Ki Young Kim;Jeong Hyun Yeum
    • Textile Coloration and Finishing
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    • v.35 no.4
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    • pp.239-245
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    • 2023
  • Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.

Effect of Metal Interlayers on Nanocrystalline Diamond Coating over WC-Co Substrate (초경합금에 나노결정질 다이아몬드 코팅 시 금속 중간층의 효과)

  • Na, Bong-Kwon;Kang, Chan Hyoung
    • Journal of the Korean institute of surface engineering
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    • v.46 no.2
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    • pp.68-74
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    • 2013
  • For the coating of diamond films on WC-Co tools, a buffer interlayer is needed because Co catalyzes diamond into graphite. W and Ti were chosen as candidate interlayer materials to prevent the diffusion of Co during diamond deposition. W or Ti interlayer of $1{\mu}m$ thickness was deposited on WC-Co substrate under Ar in a DC magnetron sputter. After seeding treatment of the interlayer-deposited specimens in an ultrasonic bath containing nanometer diamond powders, $2{\mu}m$ thick nanocrystalline diamond (NCD) films were deposited at $600^{\circ}C$ over the metal layers in a 2.45 GHz microwave plasma CVD system. The cross-sectional morphology of films was observed by FESEM. X-ray diffraction and visual Raman spectroscopy were used to confirm the NCD crystal structure. Micro hardness was measured by nano-indenter. The coefficient of friction (COF) was measured by tribology test using ball on disk method. After tribology test, wear tracks were examined by optical microscope and alpha step profiler. Rockwell C indentation test was performed to characterize the adhesion between films and substrate. Ti and W were found good interlayer materials to act as Co diffusion barriers and diamond nucleation layers. The COFs on NCD films with W or Ti interlayer were measured as less than 0.1 whereas that on bare WC-Co was 0.6~1.0. However, W interlayer exhibited better results than Ti in terms of the adhesion to WC-Co substrate and to NCD film. This result is believed to be due to smaller difference in the coefficients of thermal expansion of the related films in the case of W interlayer than Ti one. By varying the thickness of W interlayer as 1, 2, and $4{\mu}m$ with a fixed $2{\mu}m$ thick NCD film, no difference in COF and wear behavior but a significant change in adhesion was observed. It was shown that the thicker the interlayer, the stronger the adhesion. It is suggested that thicker W interlayer is more effective in relieving the residual stress of NCD film during cooling after deposition and results in stronger adhesion.