Enhancement of durability of NIR emission of Ag2S@ZnS QDs in water

2017 ◽  
Vol 31 (32) ◽  
pp. 1750297 ◽  
Author(s):  
M. Karimipour ◽  
M. Bagheri ◽  
M. Molaei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Xrd Analysis ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nir Emission ◽  
Core Shell Structure ◽  
Phase Transmission

Stability of Ag2S@ZnS QDs in water is a crucial concern for their application in biology. In this work, both physical sustainability and emission stability of Ag2S QDs were enhanced using parameter optimization of a pulsed microwave irradiation (MI) method up to 105 days after their preparation. UV–Vis and photoluminescence spectroscopies depicted an absorption and emission about 817 nm and 878 nm, respectively. X-ray diffraction (XRD) analysis showed a growth of Ag2S acanthite phase. Transmission Electron Microscopy (TEM) images revealed a clear formation of Ag2S@ZnS core–shell structure.

scholarly journals Crystallization of BaF2 from droplets of phase separated glass – evidence of a core–shell structure by ASAXS

CrystEngComm ◽  
2020 ◽  
Vol 22 (30) ◽  
pp. 5031-5039
Author(s):  
Armin Hoell ◽  
Vikram Singh Raghuwanshi ◽  
Christian Bocker ◽  
Andreas Herrmann ◽  
Christian Rüssel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Shell Structure ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Core Shell Structure

Glasses with the mol% compositions 1.88 Na2O·15.04 K2O·7.52 Al2O3·69.56 SiO2·6.00 BaF2 and 1.88 Na2O·15.03 K2O·7.52 Al2O3·69.52 SiO2·6.00 BaF2·0.05 SmF3 were studied using X-ray diffraction, transmission electron microscopy, and anomalous small-angle X-ray scattering.

Fast Synthesis of Rutile/Apatite Core/Shell Structured Photocatalyst in Simulated Body Fluid

2012 ◽  
Vol 465 ◽  
pp. 66-71 ◽  
Author(s):  
Fu Zhi Shi ◽  
Yao Gang Li ◽  
Hong Zhi Wang ◽  
Qing Hong Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Soaking Time ◽  
X Ray ◽  
Transmission Electron ◽  
Tio2 Microspheres

The core/shell structured rutile/apatite was prepared by soaking rutile TiO2 (R-TiO2) microspheres into a simulated body fluid (SBF) only for 1 day. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and N2 adsorption measurements. XRD showed that the apatite content increased with prolonging the soaking time or increasing the SBF concentration. TEM and EDX demonstrated that apatite had been coated on the surface of R-TiO2 microspheres successfully. HRTEM indicated that the lattice spacings of 0.27 nm and 0.32 nm were assigned to (211) plane of apatite and (101) plane of R-TiO2, respectively.

scholarly journals Investigation of Lithiated Carbons by Transmission Electron Microscopy and X-Ray Diffraction Analysis

1998 ◽  
Vol 548 ◽  
Author(s):  
T. D. Tran ◽  
X. Y. Song ◽  
K. Kinoshita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Lattice Image ◽  
X Ray ◽  
Storage Mechanism ◽  
Transmission Electron ◽  
Diffraction Patterns

ABSTRACTThe microstructures of lithiated synthetic graphite and carbon black were studied by high- resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analysis. Information about the crystal structure of carbon containing various Li compositions can provide useful insights to our understanding of the Li storage mechanism in carbonaceous materials. Samples with compositions of Li0.93C6or Li0.45C6 were found to contain both stage-one and stage-two compounds. These observations are consistent with XRD data. The changes in sample microstructure as the results of lithiation and exposure to electron irradiation were observed by TEM and recorded over several minutes in the microscope environment. Selected area electron diffraction patterns indicated that the lithiated samples quickly changed composition to LiC 24, which appeared to dominate during the brief analysis period. The layer planes in the lattice image of a disordered carbon black after Li insertion are poorly defined, and changes in the microstructure of these lithiated carbons was not readily apparent. Observations on these lithium intercalation compounds as well as the limitation of the experimental procedure will be presented.

Silica/Polyurea Composite: Preparation, Characterization and Study of Dielectric Constant

2016 ◽  
Vol 13 (10) ◽  
pp. 7234-7237
Author(s):  
Botong Wang ◽  
Zebo Xu ◽  
Zhiqiang Wang
Keyword(s):  
Electron Microscopy ◽  
Dielectric Constant ◽  
Hydrogen Bonds ◽  
Ultraviolet Spectroscopy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Modified Silica ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure

Silica/polyurea composite was prepared after surface modification of silica nanoparticles. Silica/polyurea composite was characterized by Fourier-transform infrared spectroscopy, ultraviolet spectroscopy, X-ray diffraction and transmission electron microscopy. The results indicate that the helical polyurea has been successfully grafted onto the surfaces of the modified silica. Silica/polyurea composite exhibits clearly core–shell structure. The ultraviolet absorption and crystallizability of silica/polyurea are changed due to the shell of helical polyurea, which possesses regular singlehanded conformation and interchain hydrogen bonds. The dielectric constant of silica/polyurea was also investigated. The result indicates that the interfacial interactions between organic shell and inorganic core increase the dielectric constant value being increased to 6.42 for silica/polyurea. The interchain hydrogen bonds of helical polyurea could also be the reason for the increasing of dielectric constant.

scholarly journals Microstructure Investigation of WC-Based Coatings Prepared by HVOF onto AZ31 Substrate

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 40
Author(s):  
Ewa Jonda ◽  
Leszek Łatka ◽  
Anna Tomiczek ◽  
Marcin Godzierz ◽  
Wojciech Pakieła ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Residual Stress ◽  
Transmission Electron Microscopy ◽  
Magnesium Alloy ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnesium Alloy Az31 ◽  
Transmission Electron ◽  
Low Elastic Modulus

In this paper, three commercial cermet powders, WC-Co-Cr, WC-Co and WC-Cr3C2-Ni, were sprayed by the High Velocity Oxy Fuel (HVOF) method onto magnesium alloy AZ31 substrate. The coatings were investigated in terms of their microstructure, phase analysis and residual stress. The manufactured coatings were analyzed extensively using optical microscopy (OM), X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM). Based on microstructure studies, it was noted that the coatings show satisfactory homogeneity. XRD analysis shows that in WC-Co, WC-Co-Cr and WC-Cr3C2-Ni coatings, main peaks are related to WC. Weaker peaks such as W2C, Co0.9W0.1, Co and W for WC-Co and W2C, Cr3C2 and Cr7C3 for WC-Cr3C2-Ni also occur. In all cermet coatings, linear stress showed compressive nature. In WC-Co and WC-Cr3C2-Ni, residual stress had a similar value, while in WC-Co-Cr, linear stress was lower. It was also proved that spraying onto magnesium substrate causes shear stress in the WC phase, most likely due to the low elastic modulus of magnesium alloy substrate.

Fabrication of Gold Nanotubes from Removable MgO Nanowires Templates

2008 ◽  
Vol 8 (11) ◽  
pp. 5715-5719 ◽  
Author(s):  
Hyoun Woo Kim ◽  
Jong Woo Lee ◽  
Mesfin A. Kebede ◽  
Hyo Sung Kim ◽  
Buddhudu Srinivasa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Metallic Structures ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Nanowires ◽  
Scanning Electron

We have prepared MgO/Au core–shell nanowires, subsequently demonstrating the fabrication of Au nanotubes by using MgO nanowires as a sacrificial template. The samples were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. MgO nanowires were coated with a conformal layer of Au via sputtering. By etching away the MgO core in aqueous (NH3)2SO4 solution, hollow nanotube-like structures of Au were readily obtained. This approach offers a potentially useful route for the fabrication of a variety of hollow metallic structures.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Multi-scale Investigation of Heterogeneous Swift Heavy Ion Tracks in Stannate Pyrochlore

2021 ◽  
Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Multi Scale ◽  
Ion Tracks ◽  
Swift Heavy Ion ◽  
Transmission Electron

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...

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