scholarly journals Синтез и свойства больших квантовых точек антимонида индия

2020 ◽  
Vol 46 (18) ◽  
pp. 15
Author(s):  
Д.В. Крыльский ◽  
Н.Д. Жуков
Keyword(s):  
Crystal Structure ◽  
Indium Antimonide ◽  
Elevated Temperatures ◽  
Synthesis Temperature ◽  
Size Difference ◽  
Spectral Maximum ◽  
Colloidal Chemistry ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm

Large (up to 20 nm) quantum dots (QD) of indium antimonide were synthesized using colloidal chemistry at elevated temperatures (250-300 °C). In terms of optical and electrophysical characteristics, they exhibit properties similar to those of conventional QD (4-5 nm), with the difference that the spectral maximum of luminescence is shifted inappropriately to the size difference. This, together with measurements of the QD shape by transmission electron microscopy, may indicate a deterioration in the perfection of the crystal structure of large QD, possibly due to insufficient synthesis temperature

Nanoporous Ni and Ni-Cu Fabricated by Dealloying

2009 ◽  
Vol 1228 ◽  
Author(s):  
Masataka Hakamada ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Noble Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm ◽  
Good Workability ◽  
Scanning Electron

AbstractMetallic nanoporous architecture can be spontaneously attained by dealloying of a binary alloy. The nanoporous architecture can be often fabricated in noble metals such as Au and Pt. In this study, nanoporous Ni, Ni-Cu are fabricated by dealloying rolled Ni-Mn and Cu-Ni-Mn alloys, respectively. Unlike conventional Raney nickel composed of brittle Ni-Al or Cu-Al intermetallic compounds, the initial alloys had good workability probably because of their fcc crystal structures. After the electrolysis of the alloys in (NH4)2SO4 aqueous solution, nanoporous architectures of Ni and Ni-Cu with pore and ligament sizes of 10–20 nm were confirmed by scanning electron microscopy and transmission electron microscopy. X-ray diffraction analyses suggested that Ni and Cu atoms form a homogeneous solid solution in the Ni-Cu nanoporous architecture. The ligament sizes of nanoporous Ni and Ni-Cu were smaller than that of nanoporous Cu, reflecting the difference between diffusivities of Ni and Cu at solid/electrolyte interface. Ni can reduce the pore and ligament sizes of resulting nanoporous architecture when added to initial Cu-Mn alloys.

Electroplated Cu Recrystallization in Damascene Structures at Elevated Temperatures

1999 ◽  
Vol 564 ◽  
Author(s):  
Qing-Tang Jiang ◽  
Michael E. Thomas ◽  
Gennadi Bersuker ◽  
Brendan Foran ◽  
Robert Mikkola ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Film Thickness ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Retardation Effect ◽  
Cu Films ◽  
Grain Sizes ◽  
Geometrical Constraints ◽  
The Difference

AbstractTransformations in electroplated Cu films from a fine to course grain crystal structure (average grain sizes went from ∼0.1 µm to several microns) were observed to strongly depend on film thickness and geometry. Thinner films underwent much slower transformations than thicker ones. A model is proposed which explains the difference in transformation rates in terms of the physical constraint experienced by the film since grain growth in thinner films is limited by film thickness. Geometrical constraints imposed by trench and via structures appear to have an even greater retardation effect on the grain growth. Experimental observations indicate that it takes much longer for Cu in damascene structures to go through grain size transformations than blanket films.

Study on the Influence of Synthesis Temperature of Anatase TiO2 Nanoparticles for Electrophoretic Deposition

2012 ◽  
Vol 620 ◽  
pp. 161-165
Author(s):  
Khatijah A. Yaacob ◽  
Jason D. Riley
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
Crystallite Size ◽  
Transmission Electron Microscope ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrolysis And Condensation ◽  
Strong Acids

The purpose of this research is to study the effect of synthesis temperature in order to produce anatase TiO2 nanoparticles (NPs) without using strong acids. In this research TiO2 nanoparticles was prepared by the hydrolysis and condensation of titanium (IV) isopropoxide in water at synthesis temperature of 0°C ± 0.1°C which produced anatase TiO2 crystallite size of 4.66 nm. XRD (X-ray diffraction) was used to analyse the crystal structure of the TiO2 and to calculate the crystallite size of the TiO2 nanoparticles. Transmission electron microscope (TEM) was also used to characterise the morphology of the TiO2 nanoparticles.

TEM study of epitactically grown GaAs/ScxEr1−xAs/GaAs heterostructures

1990 ◽  
Vol 48 (4) ◽  
pp. 586-587
Author(s):  
Jane G. Zhu
Keyword(s):  
Crystal Structure ◽  
Lattice Mismatch ◽  
New Physics ◽  
Dark Field ◽  
Salt Crystal ◽  
Plan View ◽  
Weak Beam ◽  
Transmission Electron ◽  
Potential Applications ◽  
The Difference

The incorporation of metal layers into semiconductors is attracting growing attention due to potential applications in novel electronic devices and new physics of very thin metal films in semiconductors. This paper reports the growth of GaAs/ScxEr1−xAs/GaAs (x=0 and ∼0.3) on (100) GaAs substrates by molecular beam epitaxy (MBE) and the characterization of these heterostructures by transmission electron microscopy (TEM). ErAs, ScAs and many other rare-earth arsenides have the rock-salt crystal structure, which is different from the zinc-blende structure of GaAs. The difference in the crystal structure substantially affects the heteroepitactic growth. The lattice mismatch between ErAs (ScAs) and GaAs is 1.6% (-3.3%). Lattice-matched growth of ScxEr1−xAs/GaAs can be obtained at x=0.32. TEM has been used in this study extensively to characterize the microstructure and the growth-related defects. Both cross-section and plan-view samples have been studied using strong-beam, weak-beam dark-field and high-resolution imaging, as well as selected-area diffraction.

scholarly journals Accumulation and Effect of Silver Nanoparticles Functionalized with Spirulina platensis on Rats

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2992
Author(s):  
Ludmila Rudi ◽  
Inga Zinicovscaia ◽  
Liliana Cepoi ◽  
Tatiana Chiriac ◽  
Alexandra Peshkova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Spirulina Platensis ◽  
Biochemical Tests ◽  
Hematological Indices ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm ◽  
And Control ◽  
The Brain

The effect of unmodified and functionalized Spirulina platensis biomass silver nanoparticles on rats during prolonged oral administration was assessed. Silver nanoparticles were characterized by using transmission electron microscopy, while their uptake by the biomass was confirmed using scanning electron microscopy and energy dispersive analysis. The content of silver in the different organs of rats after a period of administration (28 days) or after an additional clearance period (28 days) was ascertained by using neutron activation analysis. In animals administrated with the unmodified nanoparticles, the highest content of silver was determined in the brain and kidneys, while in animals administrated with AgNP-Spirulina, silver was mainly accumulated in the brain and testicles. After the clearance period, silver was excreted rapidly from the spleen and kidneys; however, the excretion from the brain was very low, regardless of the type of nanoparticles. Hematological and biochemical tests were performed in order to reveal the effect of nanoparticles on rats. The difference in the content of eosinophils in the experimental and control groups was statistically significant. The hematological indices of the rats did not change significantly under the action of the silver nanoparticles except for the content of reticulocytes and eosinophils, which increased significantly. Changes in the biochemical parameters did not exceed the limits of normal values. Silver nanoparticles with the sizes of 8–20 nm can penetrate the blood–brain barrier, and their persistence after a period of clearance indicated the irreversibility of this process.

Deformation twinning in materials of the A 4 (diamond) crystal structure

1956 ◽  
Vol 238 (1213) ◽  
pp. 194-203 ◽  
Keyword(s):  
Crystal Structure ◽  
Indium Antimonide ◽  
Silicon Germanium ◽  
Gallium Antimonide ◽  
Elevated Temperatures ◽  
Shear Plane ◽  
Etch Pits ◽  
Coherent Interface ◽  
Zinc Blende ◽  
Best Fit

Deformation under certain conditions causes twinning in silicon, germanium, gallium antimonide, indium antimonide and zinc blende which have the A 4 crystal structure. In material beneath hardness impressions formed at elevated temperatures a flow stress is superimposed upon hydrostatic compression; under these circumstances deformation twins form at temperatures between 0⋅44 and 0⋅74 of the absolute melting-points. Twins of the {111} type and, except in the case of zinc blende, of {123} type have been observed. Minor boundaries of thick growth twins may be {123} planes which also form boundary faces of etch pits. The only coherent interface possible between a {111} twin and matrix is a {111} plane; it is shown that among semi-coherent boundaries a {123} plane gives the best fit. The translational shears for twinning have been determined: for (111) twinning the shear is 0⋅4084 a in the [11 ¯ 2] direction with ( ¯ 110) as the shear plane; for (123) twinning the shear is 0⋅6552 a in [41 ¯ 2] direction with (1 ¯ 21) as the shear plane; where a is the parameter of the A 4 unit cell.

scholarly journals Colloidal-chemistry based synthesis of quantized CuInS2/Se2 nanoparticles

2012 ◽  
Vol 77 (6) ◽  
pp. 789-797 ◽  
Author(s):  
Nadica Abazovic ◽  
Dragana Jovanovic ◽  
Milovan Stoiljkovic ◽  
Miodrag Mitric ◽  
Phillip Ahrenkil ◽  
...  
Keyword(s):  
Size Range ◽  
Polar Solvent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Colloidal Chemistry ◽  
Quantum Size ◽  
Transmission Electron ◽  
Broad Size Distribution ◽  
Structure Morphology ◽  
20 Nm

Ternary chalcogenide nanoparticles, CuInS2 and CuInSe2, were synthesized in high- temperature boiling organic non-polar solvent. The X-ray diffraction analysis revealed that both materials have tetragonal (chalcopyrite) crystal structure. Morphology of the obtained materials was revealed by using transmission electron microscopy. Agglomerated spherical CuInS2 nanoparticles with broad size distribution in the range from 2 to 20 nm were obtained. In the case of CuInSe2, isolated particles with spherical or prismatic shape in the size range from 10 to 25 nm were obtained, as well as agglomerates consisting of much smaller particles with diameter of about 2-5 nm. The particles with the smallest diameters of both materials exhibit quantum size effect.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

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