scholarly journals DESIGN AND FABRICATION OF MICRONOZZLES

2011 ◽  
Vol 12 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Kean How Cheah ◽  
Jit Kai Chin
Keyword(s):  
Structural Material ◽  
Approximate Method ◽  
Soft Lithography ◽  
High Performance ◽  
Simple Technique ◽  
Nozzle Throat ◽  
Promising Candidate ◽  
Ion Etching ◽  
Deep Reactive Ion Etching ◽  
Throat Width

Micronozzle, a key component in micropropulsion system, has been designed and fabricated. Quasi 1D inviscid theory was used in designing a series of conical micronozzles of different expander half-angles (10°-50°). Aerospike micronozzle, a promising candidate to achieve high performance propulsion system, was designed with Angelino method (or Approximate method). Both micronozzles were fabricated using soft lithography, an inexpensive and relatively simple technique comparing to well-established deep reactive ion etching (DRIE) technique, with polydimethylsiloxane (PDMS) as structural material. Micronozzles with two different nozzle throat width, 53.5µm and 107µm, were fabricated for comparison. Microscopic inspections reveal 107µm is the more producible nozzle throat width with current equipments. The PDMS-based micronozzle can be used as cold gas microthruster system for micro- and nanosatellites.

scholarly journals Metasurface Fabrication by Cryogenic and Bosch Deep Reactive Ion Etching

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 501
Author(s):  
Angela M. Baracu ◽  
Christopher A. Dirdal ◽  
Andrei M. Avram ◽  
Adrian Dinescu ◽  
Raluca Muller ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Nanoimprint Lithography ◽  
High Performance ◽  
Reactive Ion Etching ◽  
Research Field ◽  
Si Substrate ◽  
Ion Etching ◽  
Deep Reactive Ion Etching ◽  
Aspect Ratios ◽  
Sidewall Surface

The research field of metasurfaces has attracted considerable attention in recent years due to its high potential to achieve flat, ultrathin optical devices of high performance. Metasurfaces, consisting of artificial patterns of subwavelength dimensions, often require fabrication techniques with high aspect ratios (HARs). Bosch and Cryogenic methods are the best etching candidates of industrial relevance towards the fabrication of these nanostructures. In this paper, we present the fabrication of Silicon (Si) metalenses by the UV-Nanoimprint Lithography method and cryogenic Deep Reactive Ion Etching (DRIE) process and compare the results with the same structures manufactured by Bosch DRIE both in terms of technological achievements and lens efficiencies. The Cryo- and Bosch-etched lenses attain efficiencies of around 39% at wavelength λ = 1.50 µm and λ = 1.45 µm against a theoretical level of around 61% (for Si pillars on a Si substrate), respectively, and process modifications are suggested towards raising the efficiencies further. Our results indicate that some sidewall surface roughness of the Bosch DRIE is acceptable in metalense fabrication, as even significant sidewall surface roughness in a non-optimized Bosch process yields reasonable efficiency levels.

Pharmacokinetics and Tissue Distribution Study of Ferruginol in Wistar Rat by High-performance Liquid Chromatography

2018 ◽  
Vol 15 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Guiyun Cao ◽  
Suqiao Han ◽  
Keke Li ◽  
Li Shen ◽  
Xiaohong Wang ◽  
...  
Keyword(s):  
Tissue Distribution ◽  
Mobile Phase ◽  
High Performance ◽  
Wistar Rat ◽  
Freezing And Thawing ◽  
Promising Candidate ◽  
Distribution Study ◽  
Substance Loss ◽  
Tissue Distribution Study ◽  
The Brain

Background: Ferruginol (FRGN) exhibits a broad range of pharmacological properties which make it a promising candidate for chemoprevention. However, little is known about its absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. Methods: A rapid, sensitive and specific HPLC-DAD method was established to quantify FRGN in the plasma and tissues of Wistar rats. After extraction of FRGN with ethyl acetate (EtOAc), chromatographic separation was performed on a YMC ODS C18 column (250 × 4.6 mm I.D., 5 µm) with a mobile phase consisting of methanol-water (92:8, v/v) at a flow rate of 0.9 mL/min. Detection was conducted with a wavelength of 273 nm at 25 °C. Results: The calibration curves for FRGN were linear in the concentration range of 0.5-20 µg/mL for plasma, 0.5-10 µg/mL for heart, liver, spleen, lung, kidney, stomach, intestine, brain and muscle. After three cycles of freezing and thawing, the concentration variations were within ± 7% of nominal concentrations, indicating no significant substance loss during repeated thawing and freezing. The assay was applied to pharmacokinetic and tissue distribution study in rats. Results suggested that lung, heart, liver, spleen and kidney were the major distribution tissues of FRGN in rats, and FRGN could permeate the blood-brain barrier to distribute in the brain of rats. Conclusion: The information provided by this research is very useful for gaining knowledge of the pharmacokinetic process and tissue distribution of FRGN.

Streamlined cryogenic deep reactive ion etching protocol for hybrid micronozzle arrays

2011 ◽  
Vol 21 (10) ◽  
pp. 105001
Author(s):  
Ahmet Erten ◽  
Milan Makale ◽  
Xuekun Lu ◽  
Bernd Fruhberger ◽  
Santosh Kesari ◽  
...  
Keyword(s):  
Reactive Ion Etching ◽  
Ion Etching ◽  
Deep Reactive Ion Etching

scholarly journals Correction to Ultrahigh Resolution Titanium Deep Reactive Ion Etching

2017 ◽  
Vol 9 (27) ◽  
pp. 23263-23263
Author(s):  
Bryan W. K. Woo ◽  
Shannon C. Gott ◽  
Ryan A. Peck ◽  
Dong Yan ◽  
Mathias W. Rommelfanger ◽  
...  
Keyword(s):  
Reactive Ion Etching ◽  
Ultrahigh Resolution ◽  
Ion Etching ◽  
Deep Reactive Ion Etching

Deep reactive ion etching of sub-micrometer trenches with ultra high aspect ratio

2014 ◽  
Vol 113 ◽  
pp. 35-39 ◽  
Author(s):  
Jayalakshmi Parasuraman ◽  
Anand Summanwar ◽  
Frédéric Marty ◽  
Philippe Basset ◽  
Dan E. Angelescu ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Reactive Ion Etching ◽  
Ion Etching ◽  
Deep Reactive Ion Etching

scholarly journals Loxosceles gaucho Spider Venom: An Untapped Source of Antimicrobial Agents

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 522 ◽  
Author(s):  
Paula Segura-Ramírez ◽  
Pedro Silva Júnior
Keyword(s):  
Bacterial Infections ◽  
High Performance ◽  
Antimicrobial Agents ◽  
Chemical Properties ◽  
Carcinoma Cells ◽  
Promising Candidate ◽  
Human Red Blood Cells ◽  
New Antibiotics ◽  
Conventional Antibiotics ◽  
Human Cervical Carcinoma Cells

The remarkable ability of microorganisms to develop resistance to conventional antibiotics is one of the biggest challenges that the pharmaceutical industry currently faces. Recent studies suggest that antimicrobial peptides discovered in spider venoms may be useful resources for the design of structurally new anti-infective agents effective against drug-resistant microorganisms. In this work, we found an anionic antibacterial peptide named U1-SCRTX-Lg1a in the venom of the spider Loxosceles gaucho. The peptide was purified using high-performance liquid chromatography (HPLC), its antimicrobial activity was tested through liquid growth inhibition assays, and its chemical properties were characterized using mass spectrometry. U1-SCRTX-Lg1a was found to show a monoisotopic mass of 1695.75 Da, activity against Gram-negative bacteria, a lack of hemolytic effects against human red blood cells, and a lack of cytotoxicity against human cervical carcinoma cells (HeLa). Besides this, the sequence of the peptide exhibited great similarity to specific regions of phospholipases D from different species of Loxosceles spiders, leading to the hypothesis that U1-SCRTX-Lg1a may have originated from a limited proteolytic cleavage. Our data suggest that U1-SCRTX-Lg1a is a promising candidate for the development of new antibiotics that could help fight bacterial infections and represents an exciting discovery for Loxosceles spiders.

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