Synthesis and Characterization of YB66 Nanowires

2008 ◽  
Vol 2 (1) ◽  
Author(s):  
S. Tan ◽  
P. Jash ◽  
M. Trenary
Keyword(s):  
Synthesis Method ◽  
Reaction Times ◽  
Catalyst Particle ◽  
Sem Analysis ◽  
Reaction Conditions ◽  
Tem Analysis ◽  
Analysis Techniques ◽  
Quartz Tube Furnace ◽  
Good Agreement

The objective of the current research is to synthesize yttrium boride (YB66) nanowires. Catalyst assisted growth of the nanowires under the vapor-liquid-solid (VLS) synthesis method was performed in a quartz tube furnace. The pyrolysis of diborane (B2H6) gas over yttrium oxide (Y2O3) powders with a thermally coated layer of nickel catalyst was carried out. The reaction conditions were at 925o C and a pressure of 390 mTorr with varying reaction times. SEM analysis has shown the growth of nanowires with diameters around 400 nm. A catalyst particle was also seen at the tip of the nanowires, confirming growth by the VLS mechanism. Other analysis techniques that were used include Raman spectroscopy and TEM analysis. The Raman spectra of the nanowires were in good agreement with a Raman spectrum obtained on a YB66 single crystal. However, no other evidence was obtained that the nanowires contained yttrium or that the nanowires consisted of YB66.

Synthesis and Characterization of Calcium Hexaboride (CaB6) Nanowires

2007 ◽  
Vol 1 (1) ◽  
Author(s):  
S Tan ◽  
P. Jash ◽  
M. Trenary
Keyword(s):  
Nickel Catalyst ◽  
Gas Flow ◽  
Synthesis Method ◽  
Reaction Chamber ◽  
Tem Analysis ◽  
Calcium Hexaboride ◽  
Edx Analyses ◽  
Boron Nanowires ◽  
Quartz Tube Furnace

The objective of the current research was to synthesize calcium hexaboride (CaB6) nanowires for analysis of hydrogen storage materials. Catalyst assisted growth of nanowires under the Vapor-Liquid-Solid synthesis method was performed in a quartz tube furnace. The pyrolysis of diborane (B2H6) gas over calcium oxide (CaO) powders with a thermally coated layer of nickel catalyst was carried out. SEM and TEM analysis have shown the generation of nanowires although calcium and boron did not react in a 1:6 ratio, though 1:4 and 1:8 ratios were achieved. Several types of nanowire compositions were found under EELS and EDX analyses, including calcium and oxygen coated boron nanowires. Overall, it was found that a decrease in the amount of nickel catalyst used is correlated to a decrease in the diameters of the nanowires. A higher diborane gas flow rate into the reaction chamber was also correlated to more abundant nanostructures in the sample.

scholarly journals Preparation and Characterization of Chemically-Modified Biomaterials and Their Application as Adsorbents of Penicillin G

2018 ◽  
Vol 1 (1) ◽  
pp. 114-124 ◽  
Author(s):  
Jesie Silva ◽  
Lizebel Morante ◽  
Tesfamichael Demeke ◽  
Jacqueline Baah-Twum ◽  
Abel Navarro
Keyword(s):  
Chemical Modification ◽  
Functional Groups ◽  
Negative Impact ◽  
Ph Dependence ◽  
Sem Analysis ◽  
Penicillin G ◽  
Tea Leaves ◽  
Reaction Conditions ◽  
Spent Tea Leaves

The prevalence of antibiotics in water creates microbial resistance and has a negative impact on the ecosystem. Biomaterials such as spent tea leaves are rich in functional groups and are suitable for chemical modification for diverse applications. This research proposes the use of spent tea leaves of chamomile (CM), green tea (GT), and peppermint (PM) as structural scaffolds for the incorporation of carboxyl, sulfonyl, and thiol groups to improve the adsorption of Penicillin G (Pe). Adsorbents characterization reported a higher number of acidic functional groups, mainly in thiolated products. Scanning electron microscopy (SEM) analysis showed changes on the surfaces of the adsorbents due to reaction conditions, with a stronger effect on thiolated and sulfonated adsorbents. Elemental analysis by Energy dispersive X-ray spectrophotometry (EDS) corroborated the chemical modification by the presence of sulfur atoms and the increase in oxygen/carbon ratios. Batch experiments at different pH shows a strong pH-dependence with a high adsorption at pH 8 for all the adsorbents. The adsorption follows the trend CMs > GTs > PMs. Thiolation and sulfonation reported higher adsorptions, which is most likely due to the sulfur bridge formation, reaching adsorption percentages of 25%. These results create a new mindset in the use of spent tea leaves and their chemical modifications for the bioremediation of antibiotics.

scholarly journals Aegle marmelos phytochemical stabilized synthesis and characterization of ZnO nanoparticles and their role against agriculture and food pathogen

2019 ◽  
Vol 8 (1) ◽  
pp. 488-495 ◽  
Author(s):  
J. Fowsiya ◽  
I.V. Asharani ◽  
Simron Mohapatra ◽  
Akhila Eshapula ◽  
Pragya Mohi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Sem Analysis ◽  
Aegle Marmelos ◽  
Zno Nps ◽  
Tem Analysis ◽  
Phenolic Group ◽  
Ft Ir ◽  
Agriculture And Food ◽  
Immense Potential

Abstract Nature and nanotechnology have not yet achieved a lucid correlation in the field of science but together they have exhibited immense potential towards the advancement and modification in future science and technology. Due to the unique properties of nanomaterials like nanoparticles gained considerable importance. Among all the nanoparticles, zinc oxide (ZnO NPs) are greatly utilized in sensors, catalysis, bioscience, etc. Antimicrobial activity by ZnO NPs had more attention by the implementation of nanotechnology for the preparation of ZnO NPs. At present, antimicrobial activity of ZnO NPs using Aegle marmelos (A. marmelos) leaves extract was done. The ZnO NPs subjected to UV-Vis, FT-IR, XRD, SEM and TEM analysis. The presence of phenolic group in extract has the capacity to form ZnO NPs and act as stabilizing agent. Every 5 min interval ZnO NPs was formed which recorded by UV-Vis spectrophotometer. The SEM analysis displayed a fine spherical ZnO NPs and EDAX report showed that the existence of zinc and oxygen in the ratio of 30.51% and 69.49%. The antimicrobial activity of ZnO NPs has high percentage inhibition against A. niger at 1000 ppm. Till now, no research carryout on A. marmelos mediated ZnO NPs and applications towards antimicrobial activity.

Preparation and Characterization of MCM-22 Zeolite by Varying-Temperature Hydrothermal Synthesis

2011 ◽  
Vol 197-198 ◽  
pp. 1587-1590
Author(s):  
Yue Cheng ◽  
Xiao Yuan Su ◽  
Mang Lu
Keyword(s):  
Hydrothermal Method ◽  
Amorphous Material ◽  
Sem Analysis ◽  
Bet Surface Area ◽  
N2 Adsorption ◽  
Tem Analysis ◽  
Synthesis Time ◽  
Xrd Pattern ◽  
Adsorption Desorption

MCM-22 zeolite of high crystallinity was synthesized with varying-temperature hydrothermal method. Zeolite was characterized by means of XRD, SEM, TEM and TG-DTA. XRD pattern showed that the sample was MCM-22 zeolite. SEM analysis indicated that the MCM-22 sample is in the form of thin platelet-like crystals, and no amorphous material. TEM analysis exhibited regular shaped aggregate assembled by the independent growth of many small flaky crystals. N2-adsorption/desorption analysis showed that the pore size and BET surface area of MCM-22 were 3.5 nm and 387.8 m2/g, respectively. By means of the varying-temperature hydrothermal method, synthesis time can be effectively reduced, and energy consumption also decreases.

In Situ Synthesis and Characterization of Nanosize Hydroxyapatite/Polyacrylonitrile Composite Bead

2013 ◽  
Vol 743-744 ◽  
pp. 486-490
Author(s):  
Ming Mei Xu ◽  
Wang Xiao ◽  
Yong Zhu Cui ◽  
Wei Shao ◽  
Yan Ling Sui ◽  
...  
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Sem Analysis ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Composite Bead ◽  
Composite Beads ◽  
High Conversion Ratio

nanosize hydroxyapatite/polyacrylonitrile composite bead was prepared via in-situ synthesis method. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size measurement and X-ray diffraction (XRD) were used to characterize the HAp/PAN composite bead. XRD curve indicates low crystallinity of HAp. Particle size and SEM analysis demonstrates that decreased partical size of synthesized HAp as well as good distribution with the addition of PAN is found. The HAp is well-distributed and the combination between HAp and PAN is well. FTIR showed that there was no shift of characteristic peaks of synthesized HAp in PAN, which proves the physical interaction between PAN and HAp. The approximate HAp content of 28.6% calculated from thermal analysis curves means high conversion ratio of HAp. The adsorption amount of cadmium ions onto composite beads is lower than HAp particles.

scholarly journals BIMP Catalyzed 1,3-Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones

2020 ◽  
Author(s):  
Jonathan Golec ◽  
Eve Carter ◽  
John W. Ward ◽  
William Whittingham ◽  
Luis Simon ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Linear Regression ◽  
Catalytic System ◽  
Reaction Times ◽  
Multivariate Linear Regression ◽  
Enantioselective Synthesis ◽  
Reaction Conditions ◽  
High Yields ◽  
Experimental Findings ◽  
Good Agreement

<div>A bifunctional iminophosphorane (BIMP) catalyzed enantioselective synthesis of α,β-unsaturated cyclohexenones via a facially selective 1,3-prototropic shift of β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99%) and consistently high enantioselectivity (up to 99% ee). In-depth studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out computationally on the catalytic system and the obtained data was found to be in good agreement with experimental findings.</div>

scholarly journals BIMP Catalyzed 1,3-Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones

2020 ◽  
Author(s):  
Jonathan Golec ◽  
Eve Carter ◽  
John W. Ward ◽  
William Whittingham ◽  
Luis Simon ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Linear Regression ◽  
Catalytic System ◽  
Reaction Times ◽  
Multivariate Linear Regression ◽  
Enantioselective Synthesis ◽  
Reaction Conditions ◽  
High Yields ◽  
Experimental Findings ◽  
Good Agreement

<div>A bifunctional iminophosphorane (BIMP) catalyzed enantioselective synthesis of α,β-unsaturated cyclohexenones via a facially selective 1,3-prototropic shift of β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99%) and consistently high enantioselectivity (up to 99% ee). In-depth studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out computationally on the catalytic system and the obtained data was found to be in good agreement with experimental findings.</div>

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

A technique for preparing semiconductor cross sections for both TEM and SEM analysis

1989 ◽  
Vol 47 ◽  
pp. 712-713
Author(s):  
Stanley J. Klepeis ◽  
J.P. Benedict ◽  
R.M Anderson
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Cross Sections ◽  
Sem Analysis ◽  
Preparation Technique ◽  
Ion Milling ◽  
Tem Analysis ◽  
Polished Cross Section ◽  
Area Of Interest ◽  
Polished Side

The ability to prepare a cross-section of a specific semiconductor structure for both SEM and TEM analysis is vital in characterizing the smaller, more complex devices that are now being designed and manufactured. In the past, a unique sample was prepared for either SEM or TEM analysis of a structure. In choosing to do SEM, valuable and unique information was lost to TEM analysis. An alternative, the SEM examination of thinned TEM samples, was frequently made difficult by topographical artifacts introduced by mechanical polishing and lengthy ion-milling. Thus, the need to produce a TEM sample from a unique,cross-sectioned SEM sample has produced this sample preparation technique.The technique is divided into an SEM and a TEM sample preparation phase. The first four steps in the SEM phase: bulk reduction, cleaning, gluing and trimming produces a reinforced sample with the area of interest in the center of the sample. This sample is then mounted on a special SEM stud. The stud is inserted into an L-shaped holder and this holder is attached to the Klepeis polisher (see figs. 1 and 2). An SEM cross-section of the sample is then prepared by mechanically polishing the sample to the area of interest using the Klepeis polisher. The polished cross-section is cleaned and the SEM stud with the attached sample, is removed from the L-shaped holder. The stud is then inserted into the ion-miller and the sample is briefly milled (less than 2 minutes) on the polished side. The sample on the stud may then be carbon coated and placed in the SEM for analysis.

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

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