Micro-PIXE and Micro-RBS Characterization of Micropores in Porous Silicon Prepared Using Microwave-Assisted Hydrofluoric Acid Etching

2013 ◽  
Vol 19 (2) ◽  
pp. 261-267 ◽  
Author(s):  
Muthanna Ahmad ◽  
Geoffrey W. Grime
Keyword(s):  
Porous Silicon ◽  
Hydrofluoric Acid ◽  
Large Scale ◽  
Porous Structures ◽  
Microwave Assisted ◽  
Imaging Results ◽  
Concentric Circles ◽  
First Time ◽  
Cu Ions

AbstractPorous silicon (PS) has been prepared using a microwave-assisted hydrofluoric acid (HF) etching method from a silicon wafer pre-implanted with 5 MeV Cu ions. The use of microbeam proton-induced X-ray emission (micro-PIXE) and microbeam Rutherford backscattering techniques reveals for the first time the capability of these techniques for studying the formation of micropores. The porous structures observed from micro-PIXE imaging results are compared to scanning electron microscope images. It was observed that the implanted copper accumulates in the same location as the pores and that at high implanted dose the pores form large-scale patterns of lines and concentric circles. This is the first work demonstrating the use of microwave-assisted HF etching in the formation of PS.

scholarly journals Sustainable Nanotechnologies for Curative and Preventive Wood Deacidification Treatments: An Eco-Friendly and Innovative Approach

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1744
Author(s):  
Giuliana Taglieri ◽  
Valeria Daniele ◽  
Ludovico Macera ◽  
Ralf Schweins ◽  
Sandro Zorzi ◽  
...  
Keyword(s):  
Small Angle Neutron Scattering ◽  
Large Scale ◽  
Alkaline Ph ◽  
X Ray Diffraction ◽  
Satisfactory Solution ◽  
X Ray ◽  
Atomic Force ◽  
Ancient Wood ◽  
First Time

Waterlogged wooden artifacts represent an important historical legacy of our past. They are very fragile, especially due to the severe phenomenon of acidification that may occur in the presence of acid precursors. To date, a satisfactory solution for the deacidification of ancient wood on a large scale has still not been found. In this paper, we propose, for the first time, eco-friendly curative and preventive treatments using nanoparticles (NPs) of earth alkaline hydroxides dispersed in water and produced on a large scale. We present the characterization of the NPs (by X-ray diffraction, atomic-force and electron microscopy, and small-angle neutron scattering), together with the study of the deacidification efficiency of our treatments. We demonstrate that all our treatments are very effective for both curative and preventive aims, able to assure an almost neutral or slightly alkaline pH of the treated woods. Furthermore, the use of water as a solvent paves the way for large-scale and eco-friendly applications which avoid substances that are harmful for the environment and for human health.

scholarly journals Characterization of Excavated Waste of Different Ages in View of Multiple Resource Recovery in Landfill Mining

2020 ◽  
Vol 12 (5) ◽  
pp. 1780 ◽  
Author(s):  
Isabella Pecorini ◽  
Renato Iannelli
Keyword(s):  
Large Scale ◽  
Treatment Plant ◽  
Calorific Value ◽  
Landfill Mining ◽  
Specific Objective ◽  
Methane Potential ◽  
Mining Projects ◽  
Multiple Resource ◽  
First Time

With the aim of examining the forcing factors in postmanagement landfills, in this study, excavation waste from nonhazardous municipal waste landfill in Tuscany was characterized for the first time. The specific objective was to estimate the feasibility of sampling and analyzing the excavated waste in order to define its properties and provide information about possible landfill mining projects. Based on the biochemical methane potential assays, it was shown that the excavated waste had not yet been stabilized (i.e., with a production of 52.2 ± 28.7 NlCH4/kgTS) in the landfill, probably due to the low excavated waste moisture content (36% ± 6% w/w). Furthermore, excavated waste has a high calorific value, i.e., 15.2 ± 4.1 MJ/kg; the quantity of combustibles in the industrial shredder waste (16 MJ/kg) was rather modest compared to that of municipal solid waste (20.8 MJ/Kg). In conclusion, during large scale excavation of the landfill, it was possible to evaluate how a dedicated treatment plant could be designed to treat and select waste which might appear in a different category. For excavated industrial waste, detailed mechanical sorting may be convenient for end-of-waste recovery to improve calorific value.

scholarly journals Synthesis, Crystal Structures and Characterization of Two Nonmetal Cation Tetrafluoroborates

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 812
Author(s):  
Noura Othman Alzamil ◽  
Ghareeba Mussad Al-Enzi ◽  
Aishah Hassan Alamri ◽  
Insaf Abdi ◽  
Amor BenAli
Keyword(s):  
Thermal Analysis ◽  
Hydrofluoric Acid ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Microwave Assisted

Two new nonmetal cation tetrafluoroborate phases [H3tren](BF4)3 (I) and [H3tren](BF4)3 HF (II) were synthesized by microwave-assisted solvothermal and characterized by single crystal X-ray diffraction, IR spectroscopy and thermal analysis DTA-TGA. [H3tren](BF4)3 is cubic (P213) with unit cell parameter a = 11.688(1) Å. [H3tren](BF4)3•HF is trigonal (R3c) with unit cell parameters a = 15.297(6) Å and c = 12.007(2) Å. Both (I) and (II) structures can be described from isolated tetrafluoroborate BF4- anions, triprotonated tris-(2-aminoethyl)amine (tren) [H3tren]3+. Phase (II) contains disordered BF4- tetrahedron and hydrofluoric acid.

scholarly journals Precise Identification and Characterization of Catalytically Active Sites on the Surface of γ-Alumina

2020 ◽  
Author(s):  
Konstantin Khivantsev ◽  
Nicholas R. Jaegers ◽  
Ja-Hun Kwak ◽  
János Szanyi ◽  
Libor Kovarik
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
High Surface ◽  
High Surface Area ◽  
Carbonyl Complexes ◽  
True Nature ◽  
Catalytically Active ◽  
Active Research ◽  
First Time

<p>γ-alumina is one of the oldest and most important commercial catalytic materials with high surface area and stability. These attributes enabled its use as the first commercial large-scale heterogeneous catalyst for ethanol dehydration. Despite progress in materials characterization and over a hundred years of active research, the nature of the specific sites on the surface of γ-alumina which are responsible for its unique catalytic properties has remained obscure and controversial. Herein, we identify for the first time using combined infrared spectroscopy, electron microscopy and solid-state nuclear magnetic resonance measurements that the octahedral amphoteric (O)<sub>5</sub>Al(VI)-OH sites on the massively restructured (110) facets on typical rhombus-platelet γ-alumina as well as (100) segments of irrational surfaces (invariably always present in all γ-alumina samples) are largely responsible for its unique catalytic activity. Such (O)<sub>5</sub>Al(VI)-OH sites are also present on macroscopically defined (100) facets γ-alumina of different, more elongated/rod-like geometry. They anchor organometallic fragments and isolated metal atoms. The exact mechanism by which these sites lose -OH group upon thermal dehydroxylation is clarified, resulting in coordinatively unsaturated penta-coordinate Al<sup>+3</sup>O<sub>5</sub> sites that can activate nitrogen. These coordinatively unsaturated Al penta-coordinate sites demonstrate new chemistry, producing the first well-defined thermally stable Al-carbonyl complexes. Our findings reunite and successfully clarify the contradictory findings in the literature over the last century, illuminating the true nature and the relationship between the catalytically active and coordinatively unsaturated Al sites on the surface of γ-alumina.</p>

Synthesis and Characterization of Carbon Nanotubes on Porous Silicon Substrates

2001 ◽  
Vol 7 (S2) ◽  
pp. 398-399
Author(s):  
Lifeng Dong ◽  
Jun Jiao ◽  
David W. Tuggle ◽  
Sean Foxley
Keyword(s):  
Carbon Nanotubes ◽  
Porous Silicon ◽  
Large Scale ◽  
Chemical Components ◽  
Silicon Substrates ◽  
Field Emission Displays ◽  
Pdms Elastomer ◽  
Porous Silicon Substrate ◽  
Main Barrier

Carbon nanotubes have many unique properties, including a tensile strength greater than that of steel and current-carrying capacity greater than any known metal or superconductor. Many applications have been identified, including field-emission displays and ultra-small transistors. At present, the main barrier to such applications is the ability to synthesize the nanotubes in a large scale with controlled properties'.The work reported here is an effort for growing carbon nanotubes on porous silicon with a designed pattern. Experimental procedures include (1) a liquid catalyst was prepared by mixing AlCl3.6H2O, SiCl4, FeCl3.6H2O, MoO2Cl2,P-123 chemical components; (2) a flat piece of polydimethylsiloxane (PDMS) elastomer stamp containing a designed pattern was etched in the oxygen plasma, followed by spin coating the catalyst on the patterned stamp;(3) the inked stamp was printed onto a porous silicon substrate. This substrate was then heated in air at 70°C for 10 minutes to stabilize the catalytic pattern on the surface of porous silicon.

AFM Characterization of PS Prepared in Different Concentration of Hydrofluoric Acid

2013 ◽  
Vol 669 ◽  
pp. 217-220 ◽  
Author(s):  
Shao Yuan Li ◽  
Wen Hui Ma ◽  
Yang Zhou ◽  
Xiu Hua Chen ◽  
Ming Yu Ma ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Porous Silicon ◽  
Surface Structure ◽  
Hydrofluoric Acid ◽  
Height Distribution ◽  
The Hill

The effect of HF concentration on the surface structure of porous silicon (PS) was carefully investigated by the AFM characterization. The results showed that no pores were present on PS surface which was prepared under the higher concentration of HF (10%). However, the pores were gradually visible with the HF concentration reduction. The main pores diameter was about 100 nm, when the concentration is 5.71%. The data of surface roughness and the main height distribution of the “hill” both showed an increase with the reduction of concentration, from 6.39 nm increase to 16.9 nm and from 30 nm increase to 90 nm, respectively, which implied that the pores were better exposed under the lower HF concentration.

scholarly journals Taxonomic studies on species belonging to subgenus Eutricharaea Thomson of the genus Megachile (Hymenoptera: Megachilidae)

2019 ◽  
Vol 11 (3) ◽  
pp. 612-618
Author(s):  
Priyanka Kumari ◽  
Neelima R. Kumar ◽  
Avtar K. Sidhu ◽  
Kailash Chandra
Keyword(s):  
Large Scale ◽  
Solitary Bee ◽  
Northern Plains ◽  
Spatio Temporal ◽  
Taxonomic Studies ◽  
First Time ◽  
Taxonomic Characterization ◽  
Different Parts ◽  
Conservation Of Biodiversity

Solitary bees belonging to genus Megachile are important pollinators very crucial for the wellbeing of the ecosystem. Large scale surveying will return a wealth of spatio-temporal species data which is critical for systematics, taxonomy and conservation of biodiversity. Detailed taxonomic characterization of solitary bee species belonging to subgenus Eutricharaea collected from the Sutlej basin of Indian northern plains is being described. A total of four species viz. Megachile hera Bingham, M. femorata Smith, M. vera Cameron and M. argentata Cameron belonging to subgenus Eutricharaea with 18 examples were studied. Detailed morphological descriptions, zoogeographic records, specimen examined, floral associations with illustrations and morphological measurements have been provided. Various areas finalised from different parts of Sutlej basin of northern plains were surveyed for the first time for the documentation of Megachile fauna. Hence, all these four species are first records for the studied area.

Characterization of Adhesive Joints Under Shock-Wave Loading

2016 ◽  
Author(s):  
Salih Yildiz ◽  
Daniel Shaffren ◽  
Doug Jahnke ◽  
Feridun Delale ◽  
Yiannis Andreopoulos
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Large Scale ◽  
Element Model ◽  
Adhesive Joints ◽  
Failure Behavior ◽  
Transient Strain ◽  
Experimental Values ◽  
First Time

The failure behavior of adhesive joints under shock-wave loadings was investigated in a large scale shock tube facility for the first time. An overlapping specimen consisting of two parts, one circular patch and one supporting ring were bonded together in a specially designed jig. Sub-miniature semi-conductor strain gauges were attached on the specimen to monitor the transient strain on specific locations. A high speed camera was used to record the detachment of the patch from the ring. Image processing tool was used to track the position of the patch as a function of time. This information yield estimates of velocity, acceleration and kinetic energy of the patch. A finite element model was also created and the computation results were compared to the experimental values obtained.

scholarly journals Precise Identification and Characterization of Catalytically Active Sites on the Surface of γ-Alumina

2020 ◽  
Author(s):  
Konstantin Khivantsev ◽  
Nicholas R. Jaegers ◽  
Ja-Hun Kwak ◽  
János Szanyi ◽  
Libor Kovarik
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
High Surface ◽  
High Surface Area ◽  
Carbonyl Complexes ◽  
True Nature ◽  
Catalytically Active ◽  
Active Research ◽  
First Time

<p>γ-alumina is one of the oldest and most important commercial catalytic materials with high surface area and stability. These attributes enabled its use as the first commercial large-scale heterogeneous catalyst for ethanol dehydration. Despite progress in materials characterization and over a hundred years of active research, the nature of the specific sites on the surface of γ-alumina which are responsible for its unique catalytic properties has remained obscure and controversial. Herein, we identify for the first time using combined infrared spectroscopy, electron microscopy and solid-state nuclear magnetic resonance measurements that the octahedral amphoteric (O)<sub>5</sub>Al(VI)-OH sites on the massively restructured (110) facets on typical rhombus-platelet γ-alumina as well as (100) segments of irrational surfaces (invariably always present in all γ-alumina samples) are largely responsible for its unique catalytic activity. Such (O)<sub>5</sub>Al(VI)-OH sites are also present on macroscopically defined (100) facets γ-alumina of different, more elongated/rod-like geometry. They anchor organometallic fragments and isolated metal atoms. The exact mechanism by which these sites lose -OH group upon thermal dehydroxylation is clarified, resulting in coordinatively unsaturated penta-coordinate Al<sup>+3</sup>O<sub>5</sub> sites that can activate nitrogen. These coordinatively unsaturated Al penta-coordinate sites demonstrate new chemistry, producing the first well-defined thermally stable Al-carbonyl complexes. Our findings reunite and successfully clarify the contradictory findings in the literature over the last century, illuminating the true nature and the relationship between the catalytically active and coordinatively unsaturated Al sites on the surface of γ-alumina.</p>

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

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