IN SITU ASSEMBLY OF ZnS NANOFIBERS WITH HIGHLY ORDERED LAMELLAR MESOSTRUCTURE

2006 ◽  
Vol 05 (02n03) ◽  
pp. 245-251 ◽  
Author(s):  
JUNPING LI ◽  
YAO XU ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Electron Microscope ◽  
Thermal Analyses ◽  
Blue Shift ◽  
X Rays ◽  
Energy Dispersive Analysis ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible

ZnS nanofibers with lamellar mesostructure could be built up from in situ generated ZnS precursors via hydrothermal routes using neutral n-alkylamines as structure-directing template and ethylene diamine tetraacetic acid (EDTA) as stabilizer. The morphology and structure of the obtained products were thoroughly investigated via scanning electron microscope (SEM), energy dispersive analysis of X-rays (EDX), transmission electron microscope (TEM), X-ray powder diffraction (XRD) and thermal analyses. HRTEM and XRD results revealed that the so-produced nanofibers were lamellar mesostructure and its framework was built of crystalline wurtzite ZnS . It was also found that the distance between the layers was proportional to the chain length of the alkylamine. The UV-visible absorption spectrum showed that the nanofibers exhibited strong quantum-confined effect with a blue shift in the band gap. Finally, a probable mechanism for the assembly of the nanofibers was also proposed.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

Synthesis and Characterizations of Nanocubes, Monodispersed Nanocrystals and Nanospheres of Au

2007 ◽  
Vol 353-358 ◽  
pp. 2163-2166
Author(s):  
Ming Yang ◽  
Guo Qing Zhou ◽  
Jiang Guo Zhao ◽  
Zhan Jun Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Scherrer Formula ◽  
Visible Absorption Spectroscopy

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were estimated by Debye-Scherrer formula according to XRD spectrum.

scholarly journals Preparation of Fe-DopedTiO2Nanotubes and Their Photocatalytic Activities under Visible Light

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Ultrasonic Assisted ◽  
Uv Visible

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.

Mixed-Solvothermal Preparation of Mace-Like CdS Nanocrystals

2012 ◽  
Vol 502 ◽  
pp. 164-168
Author(s):  
Ling Xu ◽  
Han Mei Hu ◽  
Hai Yan Xu
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Cds Nanostructures ◽  
Uv Visible ◽  
Solvothermal Preparation

Novel mace-like (wolf-teeth clubs) CdS nanostructures were successfully prepared on a large scale using CdCl2•2.5H2O and NH2CSNH2 as starting materials through a convenient mixed-solvothermal route. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. The experimental results reveal that the morphology of CdS products was greatly affected by the volume ratio of anhydrous ethanol and distilled water. The possible mechanism for the formation of mace-like CdS nanostructures is simply discussed.

Controlled Environment Specimen Transfer

2014 ◽  
Vol 20 (4) ◽  
pp. 1038-1045 ◽  
Author(s):  
Christian D. Damsgaard ◽  
Henny Zandbergen ◽  
Thomas W. Hansen ◽  
Ib Chorkendorff ◽  
Jakob B. Wagner
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Elevated Temperatures ◽  
Controlled Environment ◽  
Ambient Atmosphere ◽  
Air Exposure ◽  
X Ray ◽  
Environmental Transmission ◽  
Transmission Electron

AbstractSpecimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3 catalyst for methanol synthesis and a Co/Al2O3 catalyst for Fischer–Tropsch synthesis. Both systems are sensitive to ambient atmosphere as they will oxidize after relatively short air exposure. The Cu/ZnO/Al2O3 catalyst, was reduced in the in situ X-ray diffractometer set-up, and subsequently, successfully transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ transfer holder facilitates complimentary in situ experiments of the same specimen without changing the specimen state during transfer.

Routine Determination of X-Ray Detector Efficiencies Using Submicron Spheres of Pure Materials

1985 ◽  
Vol 43 ◽  
pp. 416-417
Author(s):  
Thomas F. Kelly
Keyword(s):  
Electron Microscope ◽  
Energy Range ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Characteristic Line ◽  
X Rays ◽  
Detector Efficiency ◽  
X Ray ◽  
Transmission Electron

The purpose of this paper is to outline an approach to routine determination of x-ray detector efficiencies over the entire applicable energy range that may be used on any transmission electron microscope.BACKGROUNDThe quantification of x-ray intensities using the ratio technique can be accomplished [see, for example, 1] using a relation of the form:Here, for element A, CA is the composition in the sample as a weight fraction, kA is the x-ray generation constant (see below) which contains only sample-dependent information, eA is the detector efficiency for characteristic x-rays which contains only detector-dependent information, and lA is the measured x-ray intensity in a characteristic line.

scholarly journals A rapid method of cryofixation of tissues in situ for ultracryomicrotomy.

1980 ◽  
Vol 28 (1) ◽  
pp. 47-51 ◽  
Author(s):  
S H Chang ◽  
W J Mergner ◽  
R E Pendergrass ◽  
R E Bulger ◽  
I K Berezesky ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Punch Biopsy ◽  
Sampling Device ◽  
X Ray ◽  
Cell Compartments ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Tissue Specimens

A device is described for the rapid freezing of tissue in situ by a punch biopsy approach using a specially designed cryogun with a highly thermal conductive specimen holder. The cryogun consists of a sampling device using a double, spring-loaded gun mechanism and a system of cryochambers. Ultrathin freeze-dried sections cut from samples obtained with this cryogun are relatively free of artifacts and have few ice crystals. Organelles are seen by natural contrast when cryosections of approximately 1000 A are observed with a transmission electron microscope or in the transmission mode of a scanning electron microscope. The construction of the cryogun is described along with a method of obtaining improved, ultrafast cryofixation of tissue specimens. The reliability of obtaining x-ray microanalysis measurements of diffusible ions where movement within cell compartments has been retained is discussed.

Synthesis and Characterizations of Cubic Assembly Composed of Platinum Nanoparticles

2009 ◽  
Vol 79-82 ◽  
pp. 1555-1558 ◽  
Author(s):  
Ming Yang ◽  
Xiao Yang ◽  
Jing Ma ◽  
Kai Cheng Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Platinum Nanoparticles ◽  
Photoelectron Spectra ◽  
Direct Reaction ◽  
Visible Absorption ◽  
X Ray ◽  
Platinum Particles ◽  
Uv Visible ◽  
Scanning Electron

Cubic assembly composed of platinum nanoparticles has been prepared by a simple reaction between H2PtCl6•6H2O, NaOH and NaBH4 in the presence of deionized gelatin. Gelatin played a decisive role as an inhibitor of the direct reaction of NaBH4 with H2PtCl6•6H2O and coagulation of the growing platinum in producing the cubic assembly composed. In the absence of gelatin, we can only obtain irregular large platinum particles. With decreasing the temperature, the viscosity of the solution increased. The diffusions of BH4- ions and PtCl62− ions are slower. The assembly composed of platinum nanoparticles was synthesized at 10 oC. The products were characterized by X-ray powder diffraction, scanning electron microscope, X-ray photoelectron spectra and UV-visible absorption spectroscopy. The scanning electron microscope images show the as prepared platinum with cubes and the average dimensions is about 0.35-0.45 μm. The UV-visible absorption spectrum of the as prepared platinum particles dispersed in ethanol solution shows one absorption peaks at 215nm. The size of the subunits of the polycrystalline platinum particles was calculated to be about 4 nm according to half width of the diffraction peaks using Debye–Scherer equation.

PREPARATION OF CUBE-SHAPED CdS NANOPARTICLES BY SONOCHEMICAL METHOD

2002 ◽  
Vol 01 (05n06) ◽  
pp. 437-441 ◽  
Author(s):  
HUI WANG ◽  
YINONG LU ◽  
JUNJIE ZHU
Keyword(s):  
Ultrasound Irradiation ◽  
Nucleation And Growth ◽  
Cds Nanoparticles ◽  
Microemulsion System ◽  
Sonochemical Method ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Oil In Water ◽  
Uv Visible

Cube-shaped CdS nanoparticles have been successfully prepared by a sonochemical method in an oil-in-water microemulsion. The product was characterized by using techniques including X-ray powder diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray analysis and UV-visible absorption spectroscopy. This microemulsion system in the presence of high-intensity ultrasound irradiation provides special conditions for the nucleation and growth of the CdS nanoparticles.

X-ray Energy-Dispersive Spectrometry During In Situ Liquid Cell Studies Using an Analytical Electron Microscope

2014 ◽  
Vol 20 (2) ◽  
pp. 323-329 ◽  
Author(s):  
Nestor J. Zaluzec ◽  
M. Grace Burke ◽  
Sarah J. Haigh ◽  
Matthew A. Kulzick
Keyword(s):  
Electron Microscope ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Liquid Cell

AbstractThe use of analytical spectroscopies during scanning/transmission electron microscope (S/TEM) investigations of micro- and nano-scale structures has become a routine technique in the arsenal of tools available to today’s materials researchers. Essential to implementation and successful application of spectroscopy to characterization is the integration of numerous technologies, which include electron optics, specimen holders, and associated detectors. While this combination has been achieved in many instrument configurations, the integration of X-ray energy-dispersive spectroscopy and in situ liquid environmental cells in the S/TEM has to date been elusive. In this work we present the successful incorporation/modifications to a system that achieves this functionality for analytical electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document