The Nanofabrication of Quantum Wires for the Next Generation of Thermoelectrics

1998 ◽  
Vol 545 ◽  
Author(s):  
D. L. Demske ◽  
J. L. Price ◽  
N. A. Guardala ◽  
N. Lindsey ◽  
J. H. Barkyoumb ◽  
...  
Keyword(s):  
Electron Micrographs ◽  
Quantum Wires ◽  
Incident Beam ◽  
Scanning Electron Micrographs ◽  
Carbon Ions ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ion Accelerator ◽  
Current Voltage ◽  
Potentiostatic Electrodeposition

AbstractThe fabrication of a thermoelectric nanocomposite material consisting of nanometer scale bismuth (Bi) wires embedded in a porous mica template host is discussed in detail. In fabricating the mica templates, a positive ion accelerator is employed to irradiate 10 μm thick mica sheets with collimated beams of 15 MeV carbon ions at fluence levels of 1.5 × 1013 ions/cm2. The normally incident beam generates latent nuclear damage tracks in the direction oriented perpendicularly to the mica basal plane. Atomic Force Microscope (AFM) pictures of etched tracks verify that we have fabricated porous templates containing arrays of channels with densities up to 1013/cm2 and diameters as small as 5 nanometers, thus providing pores having an aspect ratio of about 2000:1. Scanning electron micrographs of 50 nm diameter tracks show that these are parallel channels with smooth, non-tapered walls. In addition, to fabricate the wires we have developed a solution-electrodeposition process employing a PC processor-driven potentiostatic/galvanostatic system. Currently, we are electrochemically embedding 10 μm long Bi wires through the nanochannel templates. The potentiostatic electrodeposition behavior of these wires is described. Current-voltage waveforms confirm that the wires are electrically uninterrupted through the mica template. Transmission electron micrographs (TEM) show these wires are single crystals, of well-defined orientation with diameters down to 50 Å. We observe bundles of 80 Å wires with a packing density of about 109/cm2. Energy Dispersive X-ray Spectroscopy (EDS) has corroborated the presence of Bi in the nanochannels. The observation of the bismuth crystal orientation in the porous mica template is examined.

The ultrastructure of the epidermis of the redia and cercaria of Parorchis acanthus, Nicoll. A study by scanning and transmission electron-microscopy

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Electron Micrographs ◽  
Technical Assistance ◽  
Ventral Surface ◽  
The Body ◽  
Muscle Fibres ◽  
Scanning Electron Micrographs ◽  
Large Area ◽  
Transmission Electron ◽  
Parorchis Acanthus ◽  
Scanning Electron

Scanning electron-micrographs have shown the covering of microvilli on the surface of the redia of Parorchis acanthus. In the contracted state the elongated microvilli with bulbous extremities seen in the surface grooves may be the result of compression. The surface of the epidermis of the cercaria is smooth on a large area of the ventral surface and lattice-like with microvilli, laterally, anteriorly, dorsally and on the tail. The spines on the body can be withdrawn into sheaths by the contraction of muscle fibres inserted into the basement lamina below each spine.I would like to express my sincere gratitude to Dr I. ap Gwynn of this department for preparing the scanning electron-micrographs and the School of Engineering Science, University of North Wales, Bangor for the use of their stereoscan. I should also like to thank Mr M. C. Bibby for technical assistance and Professor E. G. Gray and Dr W. Sinclair for assistance with the transmission electron-micrographs.

Transmission electron microscopic study of antennal sensilla of the female black fly, Simulium arcticum (IIL-3; IIS-10.11) (Diptera: Simuliidae)

1990 ◽  
Vol 68 (7) ◽  
pp. 1443-1453 ◽  
Author(s):  
J. F. Sutcliffe ◽  
E. G. Kokko ◽  
J. L. Shipp
Keyword(s):  
Electron Micrographs ◽  
Host Location ◽  
Scanning Electron Micrographs ◽  
Antennal Sensilla ◽  
Electron Microscopic ◽  
Olfactory Sensilla ◽  
Transmission Electron Microscopic Study ◽  
Sensilla Trichodea ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

The innervation and internal ultrastructure of the antennal flagellar sensilla of female Simulium arcticum (cytotypes IIL-3 and IIS-10.11) are described from transmission electron micrographs. Two types of contact chemosensilla and at least four types of olfactory sensilla (sensilla trichodea, two or more types of sensilla basiconica, grooved pegs) were found. These correspond to sensillar types previously described from scanning electron micrographs of the antennae of these species. In addition, possible thermo- and hygro-receptive sensilla coeloconica are described from the antennal tip. The sensory complement of the simuliid antenna is compared with those of certain other dipterans, and possible roles of these sensilla in host location and other behaviours are discussed.

Metallography of Aluminum Alloys: Atlas of Microstructures

2019 ◽  
Author(s):  
S.V.S. Narayana Murty ◽  
Sushant K. Manwatkar ◽  
P. Ramesh Narayanan
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Microstructural Evolution ◽  
Electron Micrographs ◽  
Thermomechanical Processing ◽  
Alloy System ◽  
Scanning Electron Micrographs ◽  
Cast Aluminum Alloys ◽  
Transmission Electron ◽  
Evolution Of Microstructure

Microstructure plays an important role in obtaining the desired properties in metallic materials in general and aluminum alloys in particular. Mechanical properties of aluminum alloys can be significantly altered by changing the microstructure. No other alloy system can boast of as many temper conditions as aluminum alloys. With the progress in the understanding of microstructure–mechanical property relationships in these materials, “tailor made” alloys to meet specific demands are being industrially developed. The broad spectrum of aluminum alloys in wide range of temper conditions offer materials with widely varying mechanical properties for structural designers. In order to select aluminum alloys with the desired properties for the intended application, it is essential to understand the role of microstructure under actual service conditions. It is in this context “Metallography of aluminum alloys” becomes very important. This chapter provides an insight in to the microstructural evolution of aluminum alloys from the as-cast condition to the final product. Typical examples of microstructural evolution in different aluminum alloys under various thermomechanical conditions are presented here. An atlas of microstructures of commercial and experimental wrought and cast aluminum alloys is presented in an appendix to this book. This appendix includes optical photomicrographs of both cast and wrought alloys and scanning electron micrographs of polished surfaces as well as fracture surfaces of various aluminum alloys as well as transmission electron micrographs as separate annexure. Readers are encouraged to go through the optical microstructures and fractographs along with this chapter for better understanding of the evolution of microstructure as a function of alloying additions, thermomechanical processing conditions, and fracture behavior under tension.

scholarly journals Preparation, Characterization, and Application of Magnetic Fe-SBA-15 Mesoporous Silica Molecular Sieves

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Huayu Huang ◽  
Yongsheng Ji ◽  
Zhenfeng Qiao ◽  
Chuande Zhao ◽  
Jianguo He ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Magnetic Materials ◽  
Magnetic Separation ◽  
Electron Micrographs ◽  
Molecular Sieves ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Metal Form ◽  
Scanning Electron

Magnetic Fe-SBA-15 mesoporous silica molecular sieves were prepared, characterized, and used for magnetic separation. Wet impregnation, drying, and calcination steps led to iron inclusion within the mesopores. Iron oxide was reduced to the metal form with hydrogen, and the magnetic Fe-SBA-15 was obtained. Fourier-transform infrared spectroscopy confirmed the preparation process from the oxide to metal forms. The structure of magnetic materials was confirmed by Mössbauer spectra. Powder X-ray diffraction data indicated that the structure of Fe-SBA-15 retained the host SBA-15 structure. Brunauer-Emmett-Teller analysis revealed a decrease in surface area and pore size, indicating Fe-SBA-15 coating on the inner surfaces. Scanning electron micrographs confirmed the decrease in size for modified SBA-15 particles. From scanning electron micrographs, it was found that the size of the modified SBA-15 particles decreased. Transmission electron micrographs also confirmed that modified SBA-15 retained the structure of the parent SBA-15 silica. Fe-SBA-15 exhibited strong magnetic properties, with a magnetization value of 8.8 emu g-1. The iron content in Fe-SBA-15 was determined by atom adsorption spectroscopy. Fe-SBA-15 was successfully used for the magnetic separation of three aromatic compounds in water. Our results suggest wide applicability of Fe-SBA-15 magnetic materials for the rapid and efficient separation of various compounds.

scholarly journals Novel Color Change Film as a Time–Temperature Indicator Using Polydiacetylene/Silver Nanoparticles Embedded in Carboxymethyl Cellulose

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2306
Author(s):  
Aphisit Saenjaiban ◽  
Teeranuch Singtisan ◽  
Panuwat Suppakul ◽  
Kittisak Jantanasakulwong ◽  
Winita Punyodom ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Electron Micrographs ◽  
Carboxymethyl Cellulose ◽  
Fruits And Vegetables ◽  
Color Change ◽  
Color Difference ◽  
Scanning Electron Micrographs ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Total Color Difference

Time–temperature indicators (TTIs) can be important tools in product applications to monitor food quality losses, especially for fruits and vegetables. In this context, the effects of silver nanoparticles (AgNPs) and glycerol on the color change of polydiacetylene/AgNPs (PDA/AgNPs) embedded in carboxymethyl cellulose (CMC) film as time–temperature indicators (TTIs) were investigated. A CMC film prepared with 30 mg/L AgNPs and a 1:3 (v/v) PDA:AgNP ratio exhibited a faster color change than under other conditions. At 35 °C, the films with PDA/AgNPs changed color from purplish-blue to purple and purple to reddish-purple over time due to the higher thermal conductivity of AgNPs and larger PDA surface area exposed to specific temperatures. The total color difference (TCD) of PDA/AgNP-embedded CMC film directly changed with regard to time and temperature. However, adding glycerol to the system resulted in a symmetrical chemical structure, a factor that delayed the color change. Scanning electron micrographs showed AgNPs embedded in the CMC films. Transmission electron micrographs indicated a core-shell structure of PDA/AgNP vesicles in the CMC matrix. PDA/AgNP vesicles were confirmed by second derivative Fourier transform infrared spectroscopy, with a new peak at 1390–1150 cm−1. The kinetics of TTIs from PDA/AgNP-embedded CMC films yielded an activation energy of 58.70 kJ/mol.

scholarly journals Flexible Transparent Electrode Characteristics of Graphene Oxide/Cysteamine/AgNP/AgNW Structure

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2352
Author(s):  
Junhwan Jang ◽  
Ju-Young Choi ◽  
Jihyun Jeon ◽  
Jeongjun Lee ◽  
Jaehyuk Im ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Optical Transmittance ◽  
Transparent Electrode ◽  
Silver Nanowire ◽  
Bending Test ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Current Voltage

Graphene oxide (GO)–cysteamine–Ag nanoparticles (GCA)–silver nanowire (AgNW) fabricated by depositing GCA over sprayed AgNWs on PET films were proposed for transparent and flexible electrodes, and their optical, electrical, and mechanical properties were analyzed by energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, current-voltage measurements, and bending test. GCA–AgNW electrodes show optical transmittance of >80% at 550 nm and exhibit a high figure-of-merit value of up to 116.13 in the samples with sheet resistances of 20–40 Ω/◻. It was observed that the detrimental oxidation of bare AgNWs over time was considerably decreased, and the mechanical robustness was improved. To apply the layer as an actual electrode in working devices, a Pt/GO/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate/GCA–AgNW/polyethylene terephthalate structure was fabricated, and resistive switching memory was demonstrated. On the basis of these results, we confirm that the proposed GCA–AgNW layer can be used as transparent and flexible electrode.

Synthesis, Characterization and Catalytic Application of Mesoporous PW/SBA-15 for Epoxidation of α-Pinene

2012 ◽  
Vol 538-541 ◽  
pp. 2382-2386 ◽  
Author(s):  
Dan Dan Zhu ◽  
Chun Hua Wu ◽  
Chang Fu Zhuang ◽  
Guan Ben Du ◽  
Jia Yan Zhang
Keyword(s):  
Electron Micrographs ◽  
Hexagonal Structure ◽  
Scanning Electron Micrographs ◽  
The Novel ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Catalytic Application ◽  
Transmission Electron ◽  
Ft Ir ◽  
High Degree

Supported phosphotungstic acid SBA-15 were synthesized under hydrothermal conditions and characterized by X-ray diffraction (XRD), N2 adsorption, transmission electron micrographs (TEM), scanning electron micrographs (SEM), Fourier-transform infrared spectroscopy (FT-IR). XRD and FT-IR results indicated that the substitution of tungsten occurs in the silicate framework structure of SBA-15. TEM and SEM investigations confirmed the presence of ordered high degree ordering hexagonal structure in the novel PW/SBA-15 material. Their catalytic activity was evaluated in the epoxidation of α-pinene. 2,3-epoxypinane was the main product. The results of epoxidation of α-pinene by PW(40)/SBA-15 were fellows: the conversion rate of α-pinene and the selectivity were 87.61% and 79.90% respectively.

scholarly journals Electron and Light Microscopy Structure and Polysaccharide and Pectic Composition of Highbush and Rabbiteye Blueberries

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 890B-890
Author(s):  
E. Marroquin ◽  
J.L. Silva ◽  
J. Magee ◽  
J. Braswell ◽  
J. Spiers
Keyword(s):  
Electron Micrographs ◽  
Scanning Transmission Electron Microscopy ◽  
Water Soluble ◽  
Scanning Electron Micrographs ◽  
Vaccinium Ashei ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron And Light Microscopy ◽  
Highbush Blueberries ◽  
Wall Components

Rabbiteye (Vaccinium ashei) blueberries were harvested in Mississippi and highbush (V. corymbosum) blueberries were harvested in Michigan. The berries were rapidly cooled to 5C after harvest and kept at this temperature for 48 h before being analyzed as fresh fruit or freezing for later analyses. Microstructural (light and scanning/transmission electron microscopy) and chemical (pectins, cellulose, hemicellulose, lignin, and fiber) evaluations were performed to evaluate differences between the two types of blueberries. Scanning electron micrographs showed that rabbiteye spp. have thicker epidermal and subepidermal cells than highbush spp. Transmission electron micrographs also showed that rabbiteye spp. have a thicker, more uniform cuticle layer than highbush spp. Rabbiteye spp. contained higher fiber and complex polysaccharides than highbush spp. Although, there were no differences in total pectins, rabbiteye berries had lower water soluble pectins and oxalate soluble pectins than highbush blueberries. Differences in polysaccharides and pectins between highbush and rabbiteye berries indicate that their cell wall components differ. These differences, along with the variation in subepidermal, epidermal and cuticle layers of the skin, provide valuable information to explain the textural differences between rabbiteye and highbush blueberries.

Evolution of mechano-chemistry and microstructure of a calcium aluminate-polymer composite: Part II. Mixing rate effects

1996 ◽  
Vol 11 (7) ◽  
pp. 1739-1747 ◽  
Author(s):  
L. S. Tan ◽  
A. J. McHugh ◽  
M. A. Gülgün ◽  
W. M. Kriven
Keyword(s):  
Electron Micrographs ◽  
Calcium Aluminate ◽  
Particle Interaction ◽  
Polymer Particle ◽  
Crosslinking Reaction ◽  
Scanning Electron Micrographs ◽  
Mixing Rate ◽  
Microchemical Analysis ◽  
Transmission Electron ◽  
Rate Effects

Microstructure, microchemistry and mechanical properties of hardened macro-defect-free (MDF) composites processed at various rotor rates in a Banbury mixer were investigated. A quiescently formed calcium aluminate-polyvinyl alcohol composite served as a substitute for an unmixed system. Results from the Banbury studies in conjunction with microchemical analysis of the unmixed composite showed evidence that the polymer-particle interaction is a mechanically induced crosslinking reaction. The rate of the mechano-chemistry increases with mixing speeds. Scanning electron micrographs (SEM) and transmission electron micrographs (TEM) of hardened composites mixed for 15 min at 30, 50, 100, and 200 rpm indicate that much of the mechanical strength of MDF is due to the crosslinked interphase zones that blanket the cement grains. Stresses in the paste due to mixing can destroy the interphase layer, leading to a weaker hardened composite. Microchemical analysis revealed that the mechano-chemistry of the system did not vary with changes in the mixing conditions studied.

scholarly journals Sesamol: A Natural Phenolic Compound with Promising Anticandidal Potential

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Moiz A. Ansari ◽  
Zeeshan Fatima ◽  
Saif Hameed
Keyword(s):  
Phenolic Compound ◽  
Electron Micrographs ◽  
Scanning Electron Micrographs ◽  
Efflux Transporter ◽  
Antifungal Effect ◽  
Human Fungal Pathogen ◽  
Transmission Electron ◽  
Cell Wall Integrity Pathway ◽  
Antifungal Effects ◽  
Calcineurin Signaling

We investigated the antifungal effects of sesamol (Ses), a natural phenolic compound, and exemplified that it could be mediated through disruption of calcineurin signaling pathway inC. albicans, a human fungal pathogen. The repertoire of antifungal activity not only was limited toC. albicansand its six clinical isolates tested but also was against non-albicansspecies ofCandida. Interestingly, the antifungal effect of Ses affects neither the MDR efflux transporter activity nor passive diffusion of drug. We found thatC. albicanstreated with Ses copies the phenotype displayed by cells having defect in calcineurin signaling leading to sensitivity against alkaline pH, ionic, membrane, salinity, endoplasmic reticulum, and serum stresses but remained resistant to thermal stress. Furthermore, the ergosterol levels were significantly decreased by 63% confirming membrane perturbations in response to Ses as also visualized through transmission electron micrographs. Despite the fact that Ses treatment mimics the phenotype of compromised calcineurin signaling, it was independent of cell wall integrity pathway as revealed by spot assays and the scanning electron micrographs. Taken together, the data procured from this study clearly ascertains that Ses is an effectual antifungal agent that could be competently employed in treatingCandidainfections.

Sign in / Sign up

Export Citation Format

Share Document