Low temperature chemical synthesis of nanocrystalline Pb(Mg1/3Nb2/3)O3 and (1–x)Pb(Mg1/3Nb2/3)O3–xPb(Fe1/2Nb1/2)O3 (x = 0.1, 0.2, and 1) ceramics

2000 ◽  
Vol 15 (11) ◽  
pp. 2273-2275 ◽  
Author(s):  
R. N. Das ◽  
J. C. Ray ◽  
P. Pramanik
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Average Particle Size ◽  
Homogeneous Solution ◽  
Lead Magnesium Niobate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Precursor Material ◽  
Lead Magnesium ◽  
20 Nm ◽  
Iron Niobate

Nanocrystalline (20 nm) lead magnesium niobate (PMN) powders were prepared via a chemical process. This process involved the addition of aqueous niobium tartrate, lead-ethylenediaminetetraacetic acid, and magnesium-polyvinyl alcohol complex to produce a homogeneous solution. After the complete evaporation of the resulting homogeneous solution, the complexes decomposed and produced a black, fluffy precursor material. The precursor material on calcination up to 850 °C/2 h produced nanocrystalline PMN powders with the corresponding average particle size 20 nm. PMN powders modified with lead iron niobate (PFN) (1 – x)PMN–xPFN (x = 0.1, 0.2, and 1) were also prepared using this route and investigated through x-ray diffraction studies.

Blue Fluorescence in Doped LaF3 Nanocrystals Synthesized by Microwave Technique

2012 ◽  
Vol 584 ◽  
pp. 219-223
Author(s):  
S.G. Gaurkhede ◽  
M.M. Khandpekar ◽  
S.P. Pati ◽  
A.T. Singh
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hexagonal Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Blue Fluorescence ◽  
Tem Analysis ◽  
Selected Area Electron Diffraction ◽  
20 Nm

Hexagonal-phase LaF3: Ce3+, Pr3+, and Sm3+ doped (LCPS) nano-crystals have been synthesized by keeping same molarities of rare earth elements using aqueous route. The samples have been synthesized in conventional microwave on low power range in about an hour’s time. The phase formation has been verified by powder X-ray diffraction (XRD).Hexagonal geometry of the LCPS nano-crystals has been observed with an average particle size of 20 nm by TEM analysis. The JCPDS Card No. (32-0483) and selected area electron diffraction (SAED) pattern has been used for identification of crystal structure. The UV- VIS spectra indicated band gap of 5.00eV. The FTIR spectrums have been used for assignment of fundamental vibrations. Blue fluorescence observed with exciting wavelengths of 254 nm respectively. The presence of rare-earth elements in LCPS nano-crystals have been verified by the EDAX spectra.

Low-temperature chemical synthesis of nanocrystalline KTiOPO4

2002 ◽  
Vol 17 (4) ◽  
pp. 723-726 ◽  
Author(s):  
Donglin Lia ◽  
Zhihong Wang ◽  
Liangying Zhang ◽  
Xi Yao ◽  
Haoshen Zhou
Keyword(s):  
Chemical Process ◽  
Average Particle Size ◽  
Homogeneous Solution ◽  
Amorphous Powder ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Partial Evaporation ◽  
Hydrolysis Of

Nanocrystalline KTiOPO4 powders were prepared through a chemical process. This process involved the hydrolysis of KOOCCH3 · 2H2O, Ti(OC4H9)4, and PO(OR)3 to produce a homogeneous solution. A gel was formed by the partial evaporation of this solution. After the gel was decomposed at 450 °C, white amorphous powder remained. On calcinating up to 550 °C, the amorphous powder began to transform into nanocrystalline KTiOPO4 powders with an average particle size of 30–50 nm. The KTiOPO4 powders were investigated through x-ray diffraction, infrared spectroscopy, and transmission electron microscopy studies.

Investigation on the Structure and Luminescence Performance of Tb-Doped ZnO Nanocrystals Prepared by Direct Precipitation

2014 ◽  
Vol 900 ◽  
pp. 187-190
Author(s):  
Zong Hu Xiao ◽  
Wei Zhong ◽  
Kang Ping Xu ◽  
Yong Huang ◽  
Shui Gen Li ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Green Emission ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Zno Nanocrystals ◽  
Direct Precipitation ◽  
Transmission Electron ◽  
Diffraction Peaks ◽  
20 Nm

Terbium-doped zinc oxide (ZnO:Tb) nanocrystals were prepared by a direct reactive precipitation progress. Incorporation of terbium in ZnO nanocrystals had been proved by X-ray diffraction (XRD), transmission electron microscope (TEM) and fluorescence spectrophotometer. XRD investigations confirm that the samples of ZnO:Tb nanocrystals with a hexagonal wurtzite crystalline structure don’t exist the diffraction peaks of the compounds of terbium. The results of TEM analysis show that the as-prepared samples with an average particle size less than 20 nm were obtained. The photoluminescence (PL) spectra suggest that there is no luminescence peaks corresponding to the terbium compounds in ZnO:Tb samples; the green emission intensity gradually decreases with the increase of the Tb-doped concentration in ZnO matrix. A core-shell model of rare earth (RE) passivated ZnO is proposed, which the passivation layer existing on the ZnO surface, can generate a barrier to impede the formation of oxygen vacancy, corresponding to the green emission.

Synthesis of Nanophase TiO2 by Ion Beam Sputtering and Cold Condensation Technique

1998 ◽  
Vol 12 (25) ◽  
pp. 2635-2647 ◽  
Author(s):  
L. V. Saraf ◽  
S. I. Patil ◽  
S. B. Ogale ◽  
S. R. Sainkar ◽  
S. T. Kshirsager
Keyword(s):  
Particle Size ◽  
Ion Beam ◽  
Average Particle Size ◽  
Average Particle ◽  
Ion Beam Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beam Sputtering ◽  
Cold Condensation ◽  
20 Nm

Nanoparticles of TiO 2 have been synthesized by an ion beam sputtering-cold condensation (IBS-CC) technique. A sintered TiO 2 was sputtered by an ion beam (Kaufman source, 900 eV, Ar+ ions) and the ejected atoms/radicals were made to condense on a Si(l00) substrate held at -50°C. X-ray diffraction data showed that the average particle size in the as-deposited material is about 3.5 ± 1.5 nm. Upon annealing at 600°C for five hours, the average particle size was seen to increase to about 70 ± 10 nm. Further annealing for one hour at 900°C led to increase of average particle size to 200 ± 20 nm. X-ray spectroscopy, Raman spectroscopy and photoluminescence data have been used to reveal the presence and relative concentrations of rutile and anatase phases of TiO 2 in the as-deposited and annealed samples. The IBS-CC method is found to yield a more compact particle size distribution as compared to the method based on Laser Ablation.

scholarly journals Synthesis of Zirconia Nanoparticles and Their Ameliorative Roles as Additives Concrete Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Masoud Negahdary ◽  
Amir Habibi-Tamijani ◽  
Asadollah Asadi ◽  
Saeid Ayati
Keyword(s):  
Setting Time ◽  
Average Particle Size ◽  
Concrete Structures ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Split Tensile Strength ◽  
Transmission Electron ◽  
Uv Visible ◽  
20 Nm ◽  
Zirconia Nanoparticles

We investigated synthesis of zirconia nanoparticles (Nps) and their ameliorative roles as additives concrete structures. Synthesized Zirconia Nps were studied with X-ray diffraction (XRD), UV-visible spectrophotometer, and transmission electron microscope (TEM). We used standard Portland cement in related experiment Concrete Structures. The experimental or E series (E1–E4) mixtures were prepared with different amounts of ZrO2Nps with an average particle size of 20 nm. The experimental mixtures were prepared 0.125, 0.25, 0.5 and 2.0% ZrO2Nps/cement by weight. The modified cement with ZrO2nanoparticles was studied with split tensile strength, flexural strength and setting time methods. Final results showed that Zirconia Nps could be used for their Ameliorative roles as Additives Concrete Structures.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

scholarly journals Synthesis of MgO Nanoparticles by Solvent Mixed Spray Pyrolysis Technique for Optical Investigation

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
K. R. Nemade ◽  
S. A. Waghuley
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Spray Pyrolysis Technique ◽  
Average Particle Size ◽  
Band Gap Energy ◽  
Average Particle ◽  
Optical Investigation ◽  
X Ray Diffraction ◽  
Mgo Nanoparticles ◽  
Electron Microscope Analysis

Solvent mixed spray pyrolysis technique has attracted a global interest in the synthesis of nanomaterials since reactions can be run in liquid state without further heating. Magnesium oxide (MgO) is a category of the practical semiconductor metal oxides, which is extensively used as catalyst and optical material. In the present study, MgO nanoparticles were successfully synthesized using a solvent mixed spray pyrolysis. The X-ray diffraction pattern confirmed the formation of MgO phase with an excellent crystalline structure. Debye-Scherrer equation is used for the determination of particle size, which was found to be 9.2 nm. Tunneling electron microscope analysis indicated that the as-synthesized particles are nanoparticles with an average particle size of 9 nm. Meanwhile, the ultraviolet-visible spectroscopy of the resulting product was evaluated to study its optical property via measurement of the band gap energy value.

Samanea saman: A Novel Mucoadhesive Gum

2021 ◽  
pp. 57-62
Author(s):  
Nayana S. Baste ◽  
Ganesh. D. Basarkar
Keyword(s):  
Stress Measurement ◽  
Average Particle Size ◽  
Physicochemical Characterization ◽  
Qualitative Evaluation ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Natural Polymers ◽  
Chemical Evaluation ◽  
Research Article ◽  
Samanea Saman

Natural polymers are the most accepted pharmaceutical excipients of formulator’s choice. The reasons for this are their cost effectiveness, biocompatibility and availability. In this research article natural gum was extracted from the seeds of Samanea saman by using ethanol as a solvent. The physicochemical characterization like Loss on drying, Total ash and Acid insoluble ash, Swelling Index, Viscosity and qualitative evaluation of purified gum was done. The percent yield of gum was found to 6% w/w and the swelling index was found to be 18.5. Total ash value (7.5% w/w) and Acid insoluble ash value (1.4%w/w) shows purity of gum whereas 3.2% w/w loss on drying suggest low moisture content of gum. Chemical evaluation shows presence of carbohydrate. X ray diffraction graph of gum shows crystalline nature. The gum has average particle size 45.0±0.32 to 50±0.18μm, and the surface texture of the particles was found to be rough and irregular by scanning Electron Microscopy. Mucoadhesive property of gum was evaluated by Swelling index, Mucoadhesive force, Shear stress measurement. For this study polymeric tablet of gum with concentrations like 10%, 30%, 50%, 70% and 90 %w/w were formulated and the results shows best mucoadhesive and swelling property. From the above result the gum may be used in the formulation of mucoadhesive dosage form.

scholarly journals Hydrothermal synthesis of tetragonal barium titanate nanopowders under moderate conditions

2021 ◽  
Vol 15 (2) ◽  
pp. 179-183
Author(s):  
Huaxing Meng ◽  
Zhiwu Chen ◽  
Zhenya Lu ◽  
Xin Wang ◽  
Xiaoyi Fu
Keyword(s):  
Barium Titanate ◽  
Average Particle Size ◽  
Ammonia Solution ◽  
Average Particle ◽  
Titanium Hydroxide ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Uniform Size ◽  
Dominant Structure ◽  
Hydrolysis Of

Monodispersed tetragonal barium titanate (BaTiO3) nanopowders were synthesized by a convenient hydrothermal route at a low temperature of 200?C in only 24 h. The key point of this method is to promote the generation of ultrafine titanium hydroxide precipitation precursors with the help of absolute ethyl alcohol and ammonia solution during the hydrolysis of Ti(OC4H9)4. The results of X-ray diffraction and Raman spectra show that the as-prepared BaTiO3 nanopowders possess tetragonal-dominant structure. The synthesized tetragonal BaTiO3 nanopowders exhibit relatively uniform size and good dispersity, with the average particle size of 96.1 nm and a tetragonality of 1.0073, which enable broad application prospects in the field of multilayer ceramic capacitors.

Preparation and Magnetic Properties of Carbon Encapsulated Fe-Cu Alloy Nanoparticles

2010 ◽  
Vol 177 ◽  
pp. 673-676 ◽  
Author(s):  
Jun Xue ◽  
Hou Kui Xiang ◽  
Hong Qiao Ding ◽  
Shu Li Pang ◽  
Xue Hua Wang ◽  
...  
Keyword(s):  
Magnetic Measurement ◽  
Average Particle Size ◽  
Soft Magnetic Property ◽  
Copper Nitrate ◽  
Synthesis Process ◽  
Ferric Nitrate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy

Carbon encapsulated Fe-Cu alloys nanoparticles were synthesized by using ferric nitrate, copper nitrate as metal sources and using sucrose as carbon source. The synthesis process involved a step of hydrazine hydrate reduction in alcohol solution and a step of annealing carbonization. The as-prepared samples were characterized by X-ray diffraction technique, X-ray energy dispersion spectrograph, trans- mission electron microscopy and Raman spectroscopy. The results showed the sample was core / shell structure, the metalic core was crystalline FeCu4 alloy, the shell was amorphous carbon, and the average particle size was about 51nm. The magnetic measurement by using a vibrating sample magnetometer revealed that the sample has ultra-soft magnetic property with the saturation magnetization Ms of 13.01 emu/g, residual magnetization Mr of 0.37 emu/g and coercive forces Hc of 54.43 Oe at room temperature.

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