Fabrication and Testing of High Aspect Ratio Metal Micro-Gas Chromatograph Columns

2004 ◽  
Author(s):  
Abhinav Bhushan ◽  
Dawit Yemane ◽  
Jost Goettert ◽  
Edward B. Overton ◽  
Michael C. Murphy
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Gas Chromatograph ◽  
X Ray ◽  
Tubular Columns ◽  
Sensor Performance ◽  
Head Pressure ◽  
Separation Columns ◽  
The Relationship ◽  
Rectangular Columns

Micro gas chromatograph (GC) separation columns were fabricated and tested. Rectangular columns with high aspect ratio have inherent benefits over traditional tubular columns and can easily be integrated into a GC sensor system for rapid chromatographic analysis. The 2 m long, 50 μm wide, 500 μm tall columns were fabricated out of electroplated nickel through deep X-ray lithography using the LIGA technique. Critical fabrication issues including reproducible fabrication of compact footprint, deep columns and sealing of the metal columns were addressed. Experiments were conducted to establish the relationship between column head pressure and flow rate. Methane samples analyzed using hydrogen as a carrier gas on uncoated columns showed very little dispersion suggesting that there was no internal leakage in the columns. The sensor performance data compares well with other micro GC sensor systems.

Some Aspects on Thermal Degradation of Organo-Layer Silicates

2008 ◽  
Author(s):  
Mervat S. Hassan ◽  
Hassan El-Shall ◽  
Chearly Beaty
Keyword(s):  
Aspect Ratio ◽  
Thermal Degradation ◽  
High Aspect Ratio ◽  
Layered Silicates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Organically Modified ◽  
The Relationship ◽  
Thermal Stability Of

Naturally occurring silicates, like montmorillonite (MMT) have received much attention as reinforcement materials for polymers because of their potentially high aspect ratio and unique intercalation (exfoliation) characteristic. Montmorillonite is of particular interest because it has a layered structure typically about 1nm in thickness and a high aspect ratio ranging from 100 to 1500 that, with proper exfoliation, can lead to platelets with high stiffness and strength dispersed in the polymer matrix. In this paper, we studied the delamination of Egyptian bentonite and Cloisite Na+ (USA) using different onium ions. The organo-clays were characterized by X-ray diffraction (XRD), Differential Scanning Calorimeter (DSC), Derivativethermogravimetry (TGA), Thermogravimetry (TG), and Infrared spectroscopy (IR). Understanding the relationship between molecular structure of the modifying surfactant and the thermal stability of the organically modified layered silicates is critical to its processing and subsequent applications. Therefore, special emphasis is given to the study of the thermal degradation of the modified clays. The results of the thermal degradation of montmorillonite (MMT) and alkyl quaternary ammonium montmorillonite (OMMT) are discussed in this paper.

Fabrication of high aspect ratio nanoscale periodic structures by the soft X-ray interference lithography

2017 ◽  
Vol 170 ◽  
pp. 49-53 ◽  
Author(s):  
Jun Zhao ◽  
Yanqing Wu ◽  
Chaofan Xue ◽  
Shumin Yang ◽  
Liansheng Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Periodic Structures ◽  
Interference Lithography ◽  
X Ray

Formation of GaN Self-Organized Nanotips by Nanomasking Effect

2001 ◽  
Vol 707 ◽  
Author(s):  
Harumasa Yoshida ◽  
Tatsuhiro Urushido ◽  
Hideto Miyake ◽  
Kazumasa Hiramtsu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Aspect Ratio ◽  
Formation Mechanism ◽  
High Aspect Ratio ◽  
Photoelectron Spectroscopy ◽  
Nanometer Scale ◽  
Xps Analysis ◽  
X Ray ◽  
Self Organized

ABSTRACTWe have successfully fabricated self-organized GaN nanotips by reactive ion etching using chlorine plasma, and have revealed the formation mechanism. Nanotips with a high density and a high aspect ratio have been formed after the etching. We deduce from X-ray photoelectron spectroscopy (XPS) analysis that the nanotip formation is attributed to nanometer-scale masks of SiO2 on GaN. The structures calculated by Monte Carlo simulation of our formation mechanism are very similar to the experimental nanotip structures.

scholarly journals Progress in the fabrication of high-aspect-ratio zone plates by soft x-ray lithography

2002 ◽  
Author(s):  
Ralu Divan ◽  
Derrick C. Mancini ◽  
Nicolai A. Moldovan ◽  
Barry P. Lai ◽  
Lahsen Assoufid ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
X Ray ◽  
Zone Plates

Imaging properties of high aspect ratio absorption gratings for use in preclinical x-ray grating interferometry

2015 ◽  
Vol 61 (2) ◽  
pp. 527-541 ◽  
Author(s):  
Barbara Trimborn ◽  
Pascal Meyer ◽  
Danays Kunka ◽  
Marcus Zuber ◽  
Frederic Albrecht ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
X Ray ◽  
Imaging Properties
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