scholarly journals OBSERVATIONS OF SILVER COLLOIDAL PARTICLES AND SILVER GRANULES IN Ag-0-Cs PHOTOCATHODE BY ELECTRON MICROSCOPY

1979 ◽  
Vol 28 (4) ◽  
pp. 553
Author(s):  
Wu Quan-de
Keyword(s):  
Electron Microscopy ◽  
Colloidal Particles ◽  
Silver Granules

Preparation and characterization emulsion of PANI-TiO2 nanocomposite and its application as anticorrosive coating

2015 ◽  
Vol 35 (6) ◽  
pp. 597-603 ◽  
Author(s):  
Mohsen Khademian ◽  
Hossein Eisazadeh
Keyword(s):  
Electron Microscopy ◽  
Colloidal Particles ◽  
Aqueous Media ◽  
Corrosion Current ◽  
Ammonium Persulfate ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Definition Of

Abstract Emulsion nanoparticles of polyaniline (PANI) were synthesized in the aqueous media by using hydroxylpropylcellulose (HPC) as a stabilizer and ammonium persulfate as an oxidant in the presence of TiO2 with nanometer size. New poly(vinyl acetate) (PVAc) coating over carbon steel was prepared by addition of emulsion nanoparticles in different concentrations (1%, 2% and 1.5%) in PVAc as the major matrix. The Tafel plot records were used for the definition of potential and corrosion current (Icorr). Nanoparticles were characterized and compared by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By adding TiO2, the thermal stability of the nanocomposite increased. A small size of colloidal particles prevented the precipitation of conducting polymer particles and led to better dispersion of nanocomposites in the matrix of the PVAc binder; therefore, the paint was homogeneous and anticorrosion properties of the coating increased. According to the results, 1.5% of PANI-TiO2 nanocomposite in PVAc has a much lower Icorr in NaCl aqueous solution and 2% of PANI-TiO2 nanocomposite in PVAc has the best corrosion protection in HCl.

scholarly journals ARTIFACTUAL LOCALIZATION OF FERRITIN IN THE CILIARY EPITHELIUM IN VITRO

1965 ◽  
Vol 25 (2) ◽  
pp. 1-7 ◽  
Author(s):  
John Mcd. Tormey
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Basement Membrane ◽  
Osmium Tetroxide ◽  
Colloidal Particles ◽  
Ciliary Epithelium ◽  
Albino Rabbit ◽  
Cytoplasmic Matrix ◽  
Tracer Particles

The accumulation of ferritin by the ciliary epithelium of the adult albino rabbit has been studied by electron microscopy. The experiments have been carried out under in vitro conditions, such that any uptake observed should be the result of passive diffusion of the tracerparticles rather than the product of active metabolic processes. The cells were fixed in osmium tetroxide and embedded in Araldite. Ferritin was found localized in three areas: in rows of apparent vesicles, free in the cytoplasmic matrix, and in the basement membrane. Some of the conclusions reached are as follows. The appearance of tracer in rows of vesicles is not in itself an adequate demonstration of pinocytosis. The permeability of the plasma membrane is drastically increased by osmium tetroxide fixation, so that tracer particles are free to diffuse across the membrane and wander through the cytoplasm. These results indicate the serious danger of being misled by artifacts when colloidal particles are used as tracers.

Electron Microscopy and Chemistry

1967 ◽  
Vol 25 ◽  
pp. 6-7
Author(s):  
John Turkevich
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Electron Microscope ◽  
Sample Preparation ◽  
Particle Size Distribution ◽  
Colloidal Particles ◽  
Catalyst Characterization ◽  
Practical Application ◽  
Reinforcement Fiber ◽  
Polymer Research

During the last twenty-five years there has been a marked increase in the number of chemical problems that have been attacked by the various methods of electron microscopy. In addition there has been a development of sophistication in the diverse techniques of sample preparation. The electron microscope has been used in fundamental studies to characterize the texture of matter—that state of organization of matter more complex than that of larger molecules and smaller than the details that can be revealed by optical microscopy. This has brought about an understanding of the size and shape of colloidal particles, the pore distribution of membranes, the topology of surfaces and the density and character of dislocations in solids. Particle size distribution curves obtained with the electron microscope have found widespread practical application in the pigment manufacture, rubber reinforcement, fiber studies, catalyst characterization, and polymer research.

The Effects of Organic Solvent on the Electrospinning of Water-Soluble Polyacrylamide with Ultrahigh Molecular Weight

2007 ◽  
Vol 121-123 ◽  
pp. 113-116
Author(s):  
Yi Yang Zhao ◽  
X. Li ◽  
C. Wang ◽  
L.J. Li
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Molecular Weight ◽  
Scanning Electron Microscopy ◽  
Organic Solvent ◽  
Colloidal Particles ◽  
Water Soluble ◽  
Ultrahigh Molecular Weight ◽  
Scanning Electron

The effects of an organic solvent on the electrospinning of water-soluble polyacrylamide with ultrahigh molecular weight were investigated. An organic solvent, DMF, was introduced to the polyacrylamide aqueous solution and subsequently, transparent spinning solutions were obtained. The spinning solution was electrospun at the voltage of 10 kV and the electrospun products were examined by scanning electron microscopy (SEM). Results indicated that all the electrospinning products including colloidal particles, beaded fibers and smooth fibers were fabricated in the DMF/H2O bi-component solvent and the morphology of electrospun products changed from smooth fiber to beaded fiber with the increasing amount of DMF used.

scholarly journals Biosynthesis of Self-Dispersed Silver Colloidal Particles Using the Aqueous Extract of P. peruviana for Sensing dl-Alanine

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Mohd Rashid ◽  
Suhail Sabir
Keyword(s):  
Electron Microscopy ◽  
Aqueous Extract ◽  
Colloidal Particles ◽  
Chemical Sensor ◽  
Colloidal Dispersion ◽  
Single Step ◽  
Transmission Electron ◽  
Particle Size And Morphology ◽  
Uv Visible ◽  
Size And Morphology

We report the biosynthesis of silver nanoparticles (AgNPs) in a single step using edible fruit aqueous extract of P. peruviana that essentially involved the concept of green chemistry. Yellowish-brown color appeared upon adding the broth of P. peruviana to aqueous solution of 1 mM AgNO3 which indicates the formation of AgNPs. The maximum synthesis of these nanoparticles was being achieved in nearly 2 hrs at 28°C. The synthesis of AgNPs was followed by AgNPs UV-visible spectroscopy. Particle size and morphology of AgNPs were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. These studies revealed that the AgNPs characterized were spherical in shape with diameter ranging from 31 to 52 nm. The energy dispersive X-ray spectroscopy showed that the AgNPs present are approximately 63.42 percent by weight in the colloidal dispersion. The absorption spectra of the AgNPs in absence and presence of dl-alanine show a distinguish shift in surface plasmon resonance (SPR) bands. Thus, these nanoparticles may be used as a chemical sensor for dl-alanine present in the human blood.

scholarly journals THE NUCLEAR ANNULI AS PATHWAYS FOR NUCLEOCYTOPLASMIC EXCHANGES

1962 ◽  
Vol 14 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Carl M. Feldherr
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
Colloidal Gold ◽  
Colloidal Particles ◽  
Time Interval ◽  
Central Channel ◽  
Time Intervals ◽  
Gold Particles ◽  
Pass Through ◽  
Individual Particles

Colloidal gold particles, 25 to 55 A in diameter, which had been coated with polyvinylpyrrolidone, were microinjected into the ground cytoplasm of amebas (Chaos chaos). At time intervals of 1 minute, 2 minutes, 10 minutes, and 24 hours after injection the cells were fixed for electron microscopy. After 24 hours, gold particles were found in both the nuclei and the ground cytoplasm, the concentration being higher in the nuclei. Colloidal particles were also present in the nuclei after 10 minutes, but at this time interval the concentration did not appear to be greater than that in the ground cytoplasm. One and 2 minutes after injection, the gold particles were located almost exclusively in the ground cytoplasm; however, individual particles were often found within the annuli of the nuclear envelope, and were located specifically in the centers of these structures. The results suggest that at least some of the gold particles which enter the nuclei pass through the annuli, and that passage through these structures may be restricted to a central channel.

scholarly journals Characterization of a hybrid polyacrylamide and its flocculation properties in cyanide tailing suspensions

2017 ◽  
Vol 76 (9) ◽  
pp. 2482-2493 ◽  
Author(s):  
Ya Liu ◽  
Cuicui Lv ◽  
Jian Ding ◽  
Peng Qian ◽  
Yang Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Colloidal Particles ◽  
Superior Performance ◽  
Flocculation Mechanism ◽  
Organic Hybrid ◽  
Transmission Electron ◽  
Inverse Microemulsion ◽  
Inverse Microemulsion Polymerization

Abstract An inorganic-organic hybrid flocculant Al(OH)3-polyacrylamide (Al-PAM) with narrow molecular weight distribution was synthesized using inverse microemulsion polymerization. The hybrid polymer Al-PAM was characterized by Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and scanning electron microscopy, and it was found that it had a ‘star-like’ structure in which Al(OH)3 colloidal particles acted as cores linking PAM chains. The properties of Al-PAM were investigated in flocculating 10 wt% cyanide tailing suspensions. It was found that as the amount of Al-PAMM1 with high molecular weight and aluminum content increased, the initial settling rate of particles accelerated, achieving the maximum 6.6 m/h, 17.3 times the rate of the control without flocculants. The turbidity of the supernatant decreased to 35 ± 2 NTU accordingly, compared to 353 ± 2 NTU of that in the control, which meant that 90.0% of turbidity was removed from the cyanide tailing suspensions. The flocculation mechanism was further explored by floccule size and ζ potential measurements. The superior performance of cationic Al-PAM in flocculating negatively charged particles compared to commercial non-ionic GG indicated that electrostatic repulsion between tailing particles was a crucial factor in deciding the flocculation performance of the polymer. The study demonstrated that both charge neutralization and bridge adsorption were conductive to the particle flocculation.

scholarly journals ELECTRON MICROSCOPY OF ABSORPTION OF TRACER MATERIALS BY TOAD URINARY BLADDER EPITHELIUM

1965 ◽  
Vol 25 (2) ◽  
pp. 175-192 ◽  
Author(s):  
Jae Kwon Choi
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Urinary Bladder ◽  
Colloidal Particles ◽  
Intermediate Stage ◽  
Toad Urinary Bladder ◽  
Intercellular Spaces ◽  
Bladder Epithelium ◽  
Physiological Factors ◽  
Tracer Particles

The absorption of Thorotrast and saccharated iron oxide by the epithelium of the toad urinary bladder was studied by electron microscopy. Whether the toads were hydrated, dehydrated, or given Pitressin, no significant differences in transport of colloidal particles by epithelial cells were observed. This implies that these physiological factors had little effect on the transport of the tracer particles. Tracer particles were encountered in three types of epithelial cells which line the bladder lumen, but most frequently in the mitochondria-rich cells. Tracer materials were incorporated into the cytoplasm of epithelial cells after being adsorbed to the coating layer covering the luminal surface of the cells. In the intermediate stage (1 to 3 hours after introducing tracer) particles were present in small vesicles, tubules, and multivesicular bodies. In the later stages (up to 65 hours), the particles were more commonly seen to be densely packed within large membrane-bounded bodies which were often found near the Golgi region. These large bodies probably were formed by the fusion of small vesicles. Irrespective of the stages of absorption, no particles were found in the intercellular spaces or in the submucosa. Particles apparently did not penetrate the intercellular spaces of the epithelium beyond the level of the tight junction.

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