scholarly journals Density variation of nanoscale patterns in thermal nanoimprint lithography

2007 ◽  
Vol 91 (25) ◽  
pp. 253111 ◽  
Author(s):  
Young Seok Woo ◽  
Jae Kwan Kim ◽  
Dong Eon Lee ◽  
Kahp Yang Suh ◽  
Woo Il Lee
Keyword(s):  
Nanoimprint Lithography ◽  
Density Variation ◽  
Nanoscale Patterns

scholarly journals Development of Micropatterns on Curved Surfaces Using Two-Step Ultrasonic Forming

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 654
Author(s):  
Jong-Han Park ◽  
Keun Park
Keyword(s):  
Nanoimprint Lithography ◽  
Mold Insert ◽  
Curved Surfaces ◽  
Thermoplastic Polymer ◽  
Nanoscale Patterning ◽  
Flexible Polymer ◽  
Soft Mold ◽  
Nanoscale Patterns ◽  
Stretching Process ◽  
Ultrasonic Imprinting

Nanoimprint lithography (NIL) is a micro/nanoscale patterning technology on thermoplastic polymer films, and has been widely used to fabricate functional micro/nanoscale patterns. NIL was also used to develop micro/nanoscale patterns on curved surfaces by employing flexible polymer stamps or micropatterned metal molds with macroscopic curvatures. In this study, two-step ultrasonic forming was used to develop micropatterns on a curved surface out of a flat metal stamp, by connecting ultrasonic imprinting and stretching processes. Ultrasonic imprinting was used to replicate functional micropatterns on a flat polymer film, using a flat ultrasonic horn and micropatterned metal stamps with prism and dot micropatterns. An ultrasonic stretching process was then used to form a curvature on the patterned film using a curved ultrasonic horn and a soft mold insert, to avoid damage to the pre-developed micropatterns. The ultrasonic horn was designed to have three different tip radii, and the resulting forming depth and curvature formation were investigated experimentally. As a result, three different curved surfaces containing two different micropatterns were obtained. The developed curved films containing micropatterns were then evaluated optically, and showed different optical diffusion and illumination characteristics according to the film curvature and micropattern type. These results indicate that the proposed technology can extend the functionality of conventional micropatterned products by imposing appropriate curvatures.

Experimental and Numerical Analysis of Polymer Deformation in Thermal Nanoimprint Lithography

2012 ◽  
Vol 516 ◽  
pp. 269-274 ◽  
Author(s):  
Ki Hoon Shin ◽  
Hee Su Park ◽  
Hong Seok Kim
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Process Optimization ◽  
Nanoimprint Lithography ◽  
Process Condition ◽  
Polymer Materials ◽  
Process Conditions ◽  
Important Process ◽  
Polymer Deformation ◽  
Nanoscale Patterns

Nanoimprint lithography has been widely used in various applications as a promising micro/nanofabrication tool. In the thermal nanoimprint process, optimization of important process parameters such as temperature, pressure, and pressure holding time is greatly needed to successfully imprint micro-and nanoscale patterns in a resist material. In this study, both experimentation and numerical simulation were performed to extend the understanding of the behaviour of polymer materials and to optimize process condition effectively during the thermal imprint process. The effects of the process conditions on the polymer deformation are discussed to achieve a rapid and high throughput thermal imprint process.

PATTERNING OF TWO-DIMENSIONAL PHOTONIC CRYSTAL STRUCTURES BY NANOIMPRINT LITHOGRAPHY

2006 ◽  
Vol 05 (04n05) ◽  
pp. 559-563 ◽  
Author(s):  
A. CHEN ◽  
B. Z. WANG ◽  
S. J. CHUA ◽  
O. WILHELMI ◽  
SHAHRAIN B. MAHMOOD ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Process Parameters ◽  
Nanoimprint Lithography ◽  
Two Dimensional ◽  
Pmma Layer ◽  
Optimization Of Process Parameters ◽  
Nanoscale Patterns ◽  
Commercial Applications ◽  
And Control ◽  
Two Dimensional Photonic Crystal

We report on the process parameters of nanoimprint lithography for the fabrication of two-dimensional (2D) photonic crystals. The nickel mold with 2D photonic crystal patterns covering an area up to 20 mm2 is produced by electron-beam lithography and electroplating. Periodic pillars as high as 200 nm to 250 nm are produced on the mold with the diameters ranging from 180 nm to 500 nm. Optimization of process parameters is essential to generate high-quality nanoscale patterns and control the residual stress in the mold. The mold is employed for nanoimprinting on the poly-methyl-methacrylate (PMMA) layer spin-coated on the silicon substrate. Periodic air holes are formed in PMMA above its glass-transition temperature and the patterns on the mold are well transferred. This process can be utilized for commercial applications of photonic crystal devices.

Intramitochondrial Viruses of Reptilian Cell Origin

1972 ◽  
Vol 30 ◽  
pp. 318-319
Author(s):  
Philip D. Lunger ◽  
H. Fred Clark
Keyword(s):  
Particle Production ◽  
Outer Zone ◽  
Density Variation ◽  
Core Region ◽  
Mitochondrial Membranes ◽  
Virus Particles ◽  
The Core ◽  
Vipera Russelli ◽  
Maturation Stages ◽  
Type Particle

In the course of fine structure studies of spontaneous “C-type” particle production in a viper (Vipera russelli) spleen cell line, designated VSW, virus particles were frequently observed within mitochondria. The latter were usually enlarged or swollen, compared to virus-free mitochondria, and displayed a considerable degree of cristae disorganization.Intramitochondrial viruses measure 90 to 100 mμ in diameter, and consist of a nucleoid or core region of varying density and measuring approximately 45 mμ in diameter. Nucleoid density variation is presumed to reflect varying degrees of condensation, and hence maturation stages. The core region is surrounded by a less-dense outer zone presumably representing viral capsid.Particles are usually situated in peripheral regions of the mitochondrion. In most instances they appear to be lodged between loosely apposed inner and outer mitochondrial membranes.

STUDY OF HOMOGENEITY, POROSITY AND INTERNAL DEFECTS IN AERATED AND EPS AGGREGATE POLY BRICKS USING NEUTRON RADIOGRAPHY TECHNIQUE

2015 ◽  
Vol 7 (2) ◽  
pp. 1428-1439
Author(s):  
Khurshed Alam ◽  
Md. Sayeedur Rahman ◽  
Md. Mostafizur Rahman ◽  
S. M. Azaharul Islam
Keyword(s):  
Optical Density ◽  
Neutron Radiography ◽  
Density Variation ◽  
Expanded Polystyrene ◽  
Elemental Distribution ◽  
Non Destructive Testing ◽  
Internal Defects ◽  
Destructive Testing ◽  
Radiographic Images ◽  
Non Destructive

A powerful non-destructive testing (NDT) technique is adopted to study the internal defects and elemental distribution/homogeneity and porosity of aerated brick and EPS aggregate poly brick samples. In the present study the internal defects like homogeneity, porosity, elemental distribution, EPS aggregate and aerator distributor in the test samples have been observed by the measurement of gray value/optical density of the neutron radiographic images of these samples. From this measurement it is found that the neutron intensity/optical density variation with the pixel distance of the AOI of the NR images in both expanded polystyrene (EPS) aggregate poly brick and aerated brick samples comply almost same in nature with respect to the whole AOI but individually each AOI shows different nature from one AOI to another and it confirms that the elemental distribution within a AOI is almost homogeneous. Finally it was concluded that homogeneity, elemental distribution in the EPS aggregate poly brick sample is better than that of the aerated brick sample. 

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