scholarly journals Synthesis of Polymer-based ZnO/TiO2 NCs Flexible Sheets as High Dielectric Materials

2021 ◽  
Author(s):  
N. Kanwal ◽  
S. Pervaiz ◽  
A. Rasheed ◽  
M. Saleem ◽  
Ijaz Ahmad Khan
Keyword(s):  
Dielectric Permittivity ◽  
Complex Impedance ◽  
Microscopic Analysis ◽  
Dielectric Materials ◽  
Dissipation Factor ◽  
X Rays ◽  
Energy Storage Devices ◽  
Electron Microscopic ◽  
Low Dissipation ◽  
High Dielectric

Abstract Polymer-based ZnO/TiO2 NCs flexible sheets with high dielectric permittivity and low loss factor have numerous applications in light emitting and energy storage devices. In this work, polymer-based ZnO/TiO2 NCs are synthesized by co-precipitation technique. The development of various diffraction planes (X-rays diffraction analysis) related to TiO2 and ZnO phases confirms the synthesis of polycrystalline polymer-based ZnO/TiO2 NCs. The crystallinity of various phases is associated with increasing ZnO nanofillers. The surface morphology (scanning electron microscopic analysis) comprising of nanoparticles of different shapes is associated with increasing amount of nanofillers. The EDX analysis confirms the presence of Zn, O and Ti in the synthesized polymer-based ZnO/TiO2 NCs. Dielectric measurements demonstrating the sharp increase in dielectric permittivity with relatively low dissipation factor of synthesized polymer-based ZnO/TiO2 NCs are associated with increasing amount of ZnO nanofillers. The static value of dielectric constant (e’) at low frequency (100 Hz) is found to be 14.56 for sample having 10% ZnO nanofillers that is 2.11 times greater than pure PVDF and it shows relatively low value of dissipation factor. The observed σac of synthesized polymer-based ZnO/TiO2 NCs at 3.0×105 Hz and 1.0×106 Hz are ranged from 3.75-9.79 and 15.61-42.72 mS/m respectively. The decreasing complex impedance and increasing electric modulus further confirm that the synthesized polymer-based ZnO/TiO2 NCs flexible sheets are the promising candidate for better capacitive performance showing high strength and flexibility.

Fabrication of High Dielectric Materials Through Selective Insertion of Functionalized Reduced Graphene Oxide on Hard Segment of Thermoplastic Polyurethane

2021 ◽  
Vol 21 (11) ◽  
pp. 5569-5582
Author(s):  
Rakesh Manna ◽  
Suneel Kumar Srivastava ◽  
Vikas Mittal
Keyword(s):  
Graphene Oxide ◽  
Dielectric Permittivity ◽  
Reduced Graphene Oxide ◽  
Hard Segment ◽  
Thermoplastic Polyurethane ◽  
Dielectric Materials ◽  
Morphological Studies ◽  
Blending Method ◽  
Reduced Graphene ◽  
High Dielectric

The presence of microcapacitors near percolatrion threshold determines dielectric permittivity of a material. Motivated by this concept, we focused our work by preferentially allocating functionalized reduced graphene oxide (FRGO) in hard segment (disperse phase) of Thermoplastic polyurethane (TPU) by solution blending method and characterized. Morphological studies of TPU/FRGO nanocomposites established homogeneous dispersion of FRGO throughout the TPU matrix. It is noted that TPU/FRGO (1 phr) nanocomposites exhibit maximum increase in tensile strength (33%) and elongation at break (10%). Thermogravimetric analysis (TGA) showed maximum enhancement in onset of decomposition temperature (~6 °C) in 2 phr FRGO loaded TPU. Differential scanning calorimetry (DSC) analysis showed maximum reduction (~2 °C) in glass transition temperature (Tg) of soft segment of TPU followed by maximum improvements in melting temperature (~4 °C) as well as crystallization temperature (~22 °C) of hard segment compared to neat TPU. Further, a significantly high value of dielectric permittivity (401) is achieved in 1.5 phr loaded FRGO at 100 Hz due to the formation of significantly higher number of microcapacitors near the percolation threshold. It is anticipated that such thermally stable and mechanically strong high dielectric TPU/FRGO nanocomposites can find applications in the field of electronic devices.

Mineralization and biodegradation of CSF shunting systems

1987 ◽  
Vol 67 (4) ◽  
pp. 584-591 ◽  
Author(s):  
Kouhei Echizenya ◽  
Masaharu Satoh ◽  
Hiroshi Murai ◽  
Hiroo Ueno ◽  
Hiroshi Abe ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Particle Growth ◽  
X Rays ◽  
Electron Microscopic ◽  
Content Type ◽  
Csf Shunting ◽  
Scanning Electron Microscopic Analysis ◽  
Cerebrospinal Fluid Shunting ◽  
White Deposit ◽  
Surface Changes

✓ The mineralization and biodegradation of cerebrospinal fluid shunting systems were studied using material from 25 shunts that had been implanted for between 6 days and 10 years. New unused materials were also examined for comparison. Surface changes in six systems could be observed under an operating microscope. Substantial quantities of a white deposit had adhered to the tubing in four of the shunts. These changes were most advanced in the galeal penetrative portion of the shunts and are believed to have been caused by mechanical stress. Scanning electron microscopic analysis revealed surface wrinkles, microscopic holes, and tiny particles, suggesting deterioration of the material itself. An energy-dispersive analysis using x-rays demonstrated that the surface deposits were due to mineralization of calcium phosphate and that the tiny particle growth was aluminum. These changes may be a consequence of the degradation of silicone rubber. A discriminant analysis of the mineralization was carried out; thus, the age of the host and the duration of system implantation could be correlated with the incidence of mineralization (p < 0.1). A measurement of the physical properties showed progressive change with a remarkable deterioration in systems implanted for more than 5 years.

scholarly journals Dielectric Response and Transport Properties of Pb2Sr2CaCu2O9 [Lead Strontium Calcium Copper Oxide]

2017 ◽  
Vol 01 (02) ◽  
pp. 1750003
Author(s):  
Reenu Jacob ◽  
Jayakumari Isac
Keyword(s):  
Dielectric Constant ◽  
Transport Properties ◽  
Loss Factor ◽  
Dielectric Materials ◽  
Energy Storage Devices ◽  
Excellent Thermal Stability ◽  
Embedded Capacitors ◽  
Storage Devices ◽  
Materials Used ◽  
High Dielectric

High dielectric permittivity, good mechanical properties and excellent thermal stability are highly desired qualities for the dielectric materials used in embedded capacitors and energy-storage devices. This study reports the temperature dependence and very low loss factor of Pb2Sr2CaCu2O9 ceramics. X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to analyze the sample. The dielectric properties of the material prepared has been investigated in the frequency range 42–1[Formula: see text]MHz and in the temperature range 303–873[Formula: see text]K. The result reveals that Pb2Sr2CaCu2O9 have high dielectric constant with significant temperature and frequency dependence which makes them appropriate in the application of miniaturization of electronic devices. The dielectric constant and the loss factor decreases with increase in frequency of the applied field. Impedance studies confirm that dielectric relaxation in the material is of non-Debye type. Conductivity studies proves quality information related to the charge transport properties. The frequency analysis of modulus properties pictures a distribution of the relaxation time existing in the system. The new ceramic material Pb2Sr2CaCu2O9 will be a promising candidate for uses in embedded capacitors, especially in high-temperature circumstance.

Structural and Electrical Properties of Ca2+ Substituted Pb[(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02]0,96 P0,04 O3 Ceramics

2014 ◽  
Vol 87 ◽  
pp. 18-23
Author(s):  
Louanes Hamzioui ◽  
Fares Kahoul ◽  
Ahmed Boutarfaia
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Rhombohedral Phase ◽  
Dissipation Factor ◽  
Sintering Behavior ◽  
Practical Applications ◽  
Low Dissipation ◽  
High Dielectric

Pb1-xCax[(Zr0.52Ti0.48)0,98(Cr3+0.5, Ta5+0.5)0,02]0,96P0,04O3(x = 0,00, 0.02, 0.04, 0.06) ceramics were prepared using the conventional mixed-oxide route. The resultant samples were sintered at different temperatures and subsequently characterized in terms of both microstructure and dielectric properties to study the effects of sintering behavior. X-ray diffraction analysis reveals that all specimens are a pure perovskite phase without pyrochlore phase and exhibits a phase transition from a rhombohedral phase to the coexistence of rhombohedral and tetragonal phases with an increase of sintering temperature. The grain size first increases up tox= 0.02 and then decreases. Comparing with the undoped ceramics, the dielectric properties of the Ca-doped PZT–PCTP specimens are significantly improved. The results show that the ceramics sintered at 1180°C have optimum electrical properties for x= 0.02: a high dielectric constant (εr= 16800) at Tc, a low dissipation factor (tanδ = 0.009) and a low resistivity (ρ= 0.09 ×10+4) (Ω.cm) at 1 kHz, which indicates that the PZT–CCTP ceramics are promising for lead practical applications.

(Ag1-xNax)(Nb1-yTay)O3 Dielectric Ceramic Prepared through Citrate Precursor Method

2007 ◽  
Vol 280-283 ◽  
pp. 15-18 ◽  
Author(s):  
Mi Xiao ◽  
Xia Wan Wu ◽  
Kuan Xiu Song
Keyword(s):  
Ceramic Powder ◽  
Precursor Solution ◽  
Dissipation Factor ◽  
Molar Ratio ◽  
Dielectric Ceramic ◽  
Precursor Method ◽  
Low Dissipation ◽  
Wet Chemical ◽  
High Dielectric ◽  
Citrate Precursor

(Ag1-xNax)(Nb1-yTay)O3 (ANNT) dielectric ceramic material with perovskite structure was prepared through a wet chemical synthetic method. The precursor solution for the material was obtained from the citric acid solutions of different metal oxides or nitrates with exact molar ratio by a sol-process. The precursor solution thus prepared was then heated under an infrared lamp to evaporate the solvent. This period showed a self-propagating combustion behavior. Ceramic powder was obtained after the residue was calcined at a certain temperature. It is proved that ANNT sintered at 1040°C was finely grained. The obtained ceramic showed excellent high frequency dielectric properties with considerable high dielectric constant and rather low dissipation factor under 1MHz.

Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 516-520
Author(s):  
F.J. Sjostrand
Keyword(s):  
Electron Microscope ◽  
Molecular Level ◽  
Microscopic Analysis ◽  
Resolving Power ◽  
Cellular Structures ◽  
Electron Microscopic ◽  
Systematic Analysis ◽  
Technical Developments ◽  
Thin Sectioning ◽  
Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

Electron Microscopic Analysis of Myonecrosis Induced by a Pure Component Isolated From Rattlesnake Venom

1976 ◽  
Vol 34 ◽  
pp. 292-293
Author(s):  
Charlotte L. Ownby ◽  
David Cameron ◽  
Anthony T. Tu
Keyword(s):  
Gel Filtration ◽  
Microscopic Analysis ◽  
The United States ◽  
Exchange Chromatography ◽  
Pure Component ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Mouse Muscle ◽  
Major Health Problem ◽  
Rattlesnake Venom

In the United States the major health problem resulting from snakebite poisoning is local tissue damage, i.e. hemorrhage and myonecrosis. Since commercial antivenin does not usually prevent such damage to tissue, a more effective treatment of snakebite-induced myonecrosis is needed. To aid in the development of such a treatment the pathogenesis of myonecrosis induced by a pure component of rattlesnake venom was studied at the electron microscopic level.The pure component, a small (4,300 mol. wt.), basic (isoelectric point of 9.6) protein, was isolated from crude prairie rattlesnake (Crotalus viridis viridis) venom by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25), and shown to be pure by electrophoresis. Selection of the myotoxic component was based on light microscopic observations of injected mouse muscle.

Correlative video enhanced differential interference contrast light microscopy (VDIC)-LM), low-voltage high-resolution SEM (LV-HR-SEM), and high-voltage electron microscopy (HVEM) in the observation of gold-labelled surface antigens and the subjacent cytoskeletal matrix

1989 ◽  
Vol 47 ◽  
pp. 904-905
Author(s):  
Ralph M. Albrecht ◽  
Scott R. Simmons ◽  
Marek Malecki
Keyword(s):  
High Resolution ◽  
Light Microscopy ◽  
Low Voltage ◽  
Microscopic Analysis ◽  
Cell Labelling ◽  
Video Technology ◽  
Electron Microscopic ◽  
Image Capture ◽  
High Voltage Electron Microscopy ◽  
Fluorescence Studies

The development of video-enhanced light microscopy (LM) as well as associated image processing and analysis have significantly broadened the scope of investigations which can be undertaken using (LM). Interference/polarization based microscopies can provide high resolution and higher levels of “detectability” especially in unstained living systems. Confocal light microscopy also holds the promise of further improvements in resolution, fluorescence studies, and 3 dimensional reconstruction. Video technology now provides, among other things, a means to detect differences in contrast difficult to detect with the human eye; furthermore, computerized image capture, processing, and analysis can be used to enhance features of interest, average images, subtract background, and provide a quantitative basis to studies of cells, cell features, cell labelling, and so forth. Improvements in video technology, image capture, and cost-effective computer image analysis/processing have contributed to the utility and potential of the various interference and confocal microscopic instrumentation.Electron microscopic technology has made advances as well. Microprocessor control and improved design have contributed to high resolution SEMs which have imaging capability at the molecular level and can operate at a range of accelerating voltages starting at 1KV. Improvements have also been seen in the HVEM and IVEM transmission instruments. As a whole, these advances in LM and EM microscopic technology provide the biologist with an array of information on structure, composition, and function which can be obtained from a single specimen. Corrrelative light microscopic analysis permits examination of living specimens and is critical where the “history” of a cell, cellular components, or labels needs to be known up to the time of chemical or physical fixation. Features such as cytoskeletal elements or gold label as small as 0.01 μm, well below the 0.2 μm limits of LM resolution, can be “detected” and their movement followed by VDIC-LM. Appropriate identification and preparation can then lead to the examination of surface detail and surface label with stereo LV-HR-SEM. Increasing the KV in the HR-SEM while viewing uncoated or thinly coated specimens can provide information from beneath the surface as well as increasing Z contrast so that positive identification of surface and subsurface colloidal gold or other heavy metal labelled/stained material is possible. Further examination of the same cells using stereo HVEM or IVEM provides information on internal ultrastructure and on the relationship of labelled material to cytoskeletal or organellar distribution, A wide variety of investigations can benefit from this correlative approach and a number of instrumentational configurations and preparative pathways can be tailored for the particular study. For a surprisingly small investment in time and technique, it is often possible to clear ambiguities or questions that arise when a finding is presented in the context of only one modality.

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