scholarly journals Effects of CeO2 and Sb2O3 on the Nonlinear Photochemical Process in Ultrashort Laser Gaussian—Bessel Beams Irradiated Photo—Thermo—Refractive Glass

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 615
Author(s):  
Xu Wang ◽  
Guodong Zhang ◽  
Guangying Li ◽  
Rui Lou ◽  
Zhe Sun ◽  
...  
Keyword(s):  
Microfluidic Chips ◽  
X Ray Diffraction ◽  
Bessel Beams ◽  
Optical Elements ◽  
Photochemical Process ◽  
Co Doping ◽  
Fs Laser ◽  
Average Size ◽  
Electron Transfer Processes ◽  
Ultrashort Laser

Microfluidic chips and optical elements can be fabricated based on the nonlinear photosensitivity in photo–thermo–refractive (PTR) glass by controlling the growth of nanocrystals in the femtosecond (fs) laser–irradiated region. Here, we focus on CeO2 and Sb2O3 that play important roles in UV irradiation, experimentally investigate the effects of the dopants on the nonlinear photochemical process in PTR glass triggered by fs Gaussian–Bessel beams. The results show that the generation of Ag0 atoms and the Ag nanoparticles can be improved by CeO2 and Sb2O3 co–doping. Besides, each multivalent ion in PTR glass possibly participates in the electron transfer processes and contributes to the generation of Ag0 atoms. Finally, X–ray diffraction analysis reveals the precipitation of NaF nanocrystals with an average size of 10 to 12 nm after laser irradiation and thermal treatment, which is unrelated to the dopants.

In Vitro Assessment of Hydroxyapatite Coating on the Surface of Additive Manufactured Ti6Al4V Scaffolds

2016 ◽  
Vol 879 ◽  
pp. 2444-2449 ◽  
Author(s):  
Ekaterina Chudinova ◽  
Maria Surmeneva ◽  
Andrey Koptioug ◽  
Irina V. Savintseva ◽  
Irina Selezneva ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Human Mesenchymal Stem Cells ◽  
Nanocrystalline Structure ◽  
X Ray Diffraction ◽  
Ha Coating ◽  
Magnetron Sputter Deposition ◽  
In Vitro Assessment ◽  
Average Size

Custom orthopedic and dental implants may be fabricated by additive manufacturing (AM), for example using electron beam melting technology. This study is focused on the modification of the surface of Ti6Al4V alloy coin-like scaffolds fabricated via AM technology (EBM®) by radio frequency (RF) magnetron sputter deposition of hydroxyapatite (HA) coating. The scaffolds with HA coating were characterized by Scanning Electron microscopy, X-ray diffraction. HA coating showed a nanocrystalline structure with the crystallites of an average size of 32±9 nm. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells was studied using biological short-term tests in vitro. In according to in vitro assessment, thin HA coating stimulated the attachment and proliferation of cells. Human mesenchymal stem cells cultured on the HA-coated scaffold also formed mineralized nodules.

Eine elektrochemische und strukturelle Studie an den Eisensilylamiden Fe[N(SiMe3)2]2 und Fe[N(SiMe3)2]3 / An Electrochemical and Structural Study of the Iron Silylamides Fe[N(SiMe3)2]2 and Fe[N(SiMe3)2]3

2012 ◽  
Vol 67 (6) ◽  
pp. 549-556 ◽  
Author(s):  
Günter Margraf ◽  
Frauke Schödel ◽  
Inge Sänger ◽  
Michael Bolte ◽  
Matthias Wagner ◽  
...  
Keyword(s):  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Amido Complexes ◽  
X Ray ◽  
Redox Transition ◽  
Transfer Processes ◽  
Irreversible Oxidation ◽  
Reaction Solution ◽  
Reversible Redox ◽  
Electron Transfer Processes

The bis(trimethyl)silylamido complex Na(THF){Fe[N(SiMe3)2]3} and the disilane tBu3SiSitBu3 were obtained from the reaction of Fe[N(SiMe3)2]3 with the sodium silanide Na(THF)2[SitBu3] in a mixture of benzene and THF. Single crystals of Na(THF){Fe[N(SiMe3)2]3} suitable for X-ray diffraction were grown from the reaction solution at ambient temperature (orthorhombic, C2221, Z = 4). The solid-state structure features a contact-ion pair with two short N-Na contacts. The THF adducts {M(THF)2[N(SiMe3)2]2} reacted with 2,2´-bipyridine to give the corresponding complexes {M(2,2´bipy)[N(SiMe3)2]2} (M= Mn; Fe). Their structures (M= Fe: orthorhombic, Pca21, Z = 8; M = Mn: orthorhombic, Pbca, Z = 8) feature monomeric units. The cyclic voltammogram of Fe[N(SiMe3)2]3 revealed a reversible redox transition with the potential of -0;523 V (E½), which was assigned to the Fe(III)[N(SiMe3)2]3 → Fe(II)[N(SiMe3)2]-3 redox transition, whereas the compounds {Fe(THF)2[N(SiMe3)2]2} (Eox = -0;379 V) and {Fe(2,2´bipy)[N(SiMe3)2]2} (Eox = -0;436 V) featured irreversible oxidation waves. The related manganese bis(trimethylsilyl)amido complexes {Mn(THF)2[N(SiMe3)2]2} (Eox = -0;458 V) and {Mn(2,2´bipy)[N(SiMe3)2]2} (Eox = -0513 V) also underwent irreversibile electron transfer processes.

The effect of silver concentration and calcination temperature on structural and optical properties of ZnO:Ag nanoparticles

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Visible Emission ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

Effect of Yttria-Stabilized Zirconia Concentration in an Electroless Bath on Microstructure and Composition of Ni/Yttria-Stabilized Zirconia Nanocomposite

2021 ◽  
Vol 21 (11) ◽  
pp. 5592-5602
Author(s):  
Samira Almasi ◽  
Ali Mohammad Rashidi
Keyword(s):  
High Performance ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Nickel Ion ◽  
Nanocomposite Particles ◽  
X Ray ◽  
Ni Content ◽  
Naoh Solution ◽  
Average Size

The effect of the yttria-stabilized zirconia (YSZ) nanoparticle loading in an electro-less bath was considered as one of the vital synthesis variables for control Ni content and microstructure of prepared nanocomposite particles, which are two crucial factors to achieving high-performance SOFC anode. Nanocomposite particles were prepared using a simple electroless method without any expensive pretreatment of sensitizing by Sn2+ ions as well as activating by Pd2+ ions that are usually used to apply nickel coating on the surface of a non-conductive substrate. The process was performed by adding YSZ nanoparticles into NaOH solution, separating them from the solution by the centrifugal method, then providing several water-based nanofluids with different concentrations of activated YSZ nanoparticles, mixing them with NiCI2 solution, followed by adding the hydrazine and then NaOH solution. X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis were used to analyze the prepared nanocomposite particles. It is observed that after adding YSZ nanoparticles into the NaOH solution, the pH of the solution varied gradually from a starting pH of 10.2 to 9. Also, by increasing the YSZ nanoparticles loading in the electroless bath from 76 mg/l to 126 mg/l, the grain size of Ni deposits, the Ni content and the average size of the prepared nanocomposite particles decreased. The electrochemical mechanism previously proposed for the nickel ion reduction was modified, and a novel analytical model was proposed for variation of the efficiency of Ni deposition with YSZ nanoparticles loading.

Microwave-Assisted Hydrothermal Synthesis of ZnFe2O4/TiO2 Composite and Photocatalytic Properties

2018 ◽  
Vol 788 ◽  
pp. 102-107
Author(s):  
Pavels Rodionovs ◽  
Jānis Grabis ◽  
Aija Krūmiņa
Keyword(s):  
Photocatalytic Activity ◽  
Photon Absorption ◽  
Light Sources ◽  
Mass Loading ◽  
Spherical Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Average Size ◽  
Prepared Nanostructures

In order to improve TiO2 photocatalytic activity ZnFe2O4/TiO2 nanocomposites with different ZnFe2O4 mass loading were produced. Obtained ZnFe2O4 nanoparticles were coupled with TiO2 via microwave-assisted hydrothermal method in order to improve photon absorption in a range of visible light. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Photocatalytic activity of prepared samples was investigated by degradation of methylene blue under different light sources – LED, Hg and Osram Vitalux lamps. ZnFe2O4 consists of spherical nanoparticles with average size of 15 nm. TiO2 spherical nanoparticles size is in a range of 30÷45 nm. The results show that doping TiO2 with ZnFe2O4 nanoparticles increases photocatalytic activity. Photocatalytic activity increases as mass loading of ZnFe2O4 decreases.

scholarly journals Study the Effect of Water Content on the Structure of Electrochemically Prepared TiO2 Nanotubes

2022 ◽  
Author(s):  
Sara Al-Waisawy ◽  
Ahmed Kareem Abdullah ◽  
Hadi A. Hamed ◽  
Ali A. Al-bakri
Keyword(s):  
Water Content ◽  
Pure Titanium ◽  
Electrochemical Anodization ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Titania Nanotube Arrays ◽  
Anodization Process ◽  
Titania Films ◽  
Average Size

In this research, the pure titanium foil was treated in glycerol base electrolyte with 0.7 wt.% NH4F and a small amount of H2O at 17 V for 2 hours by electrochemical anodization process in order to prepare Titania nanotube arrays at room temperature (~25 ºC), different water content was added to the electrolyte as a tube enhancing agent. The high density uniform arrays are prepared by using organized and well aligned these tubes. The average size of tube diameter, ranging from 57 to 92 nm which found it increases with increasing water content, and the length of the tube ranging from 2.76 to 4.12 µm, also found to increase with increasing water content and ranging in size of wall thickness from 23 to 35 nm. A possible growth mechanism is presented. The X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were utilized to study the structure and morphology of the Titania films.

scholarly journals Получение карбида бора в низковольтной электрической дуге постоянного тока, инициированной в открытом воздушном пространстве

2018 ◽  
Vol 44 (14) ◽  
pp. 26 ◽  
Author(s):  
А.Я. Пак ◽  
Г.Я. Мамонтов
Keyword(s):  
Boron Carbide ◽  
Arc Discharge ◽  
Electron Microscopic Examination ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Vacuum Equipment ◽  
X Ray ◽  
Gas Atmosphere ◽  
Average Size ◽  
Carbide Particles

AbstractWe describe a method of obtaining ultrafine boron carbide (B_13C_2) powder using the effect of a dc electric arc on a mixture of initial reactants containing carbon and boron. A peculiarity of the proposed method is that it can be implemented using arc discharge operating in open air without any vacuum equipment and protective inert gas atmosphere. X-ray diffraction data showed that the synthesized product in the general case contained three crystalline phases: boron carbide (B_13C_2), graphite (C), and boron oxide (B_2O_3). Electron-microscopic examination showed that the average size of boron carbide particles ranged from ~50 nm to ~2 μm.

scholarly journals Síntese, caracterização e estabilidade de nanopartículas de magnetita

2021 ◽  
Vol 3 (4) ◽  
pp. 2738-2749
Author(s):  
Monise Cristina Ribeiro Casanova Coltro ◽  
Warde Antonieta da Fonseca-Zang ◽  
Joachim Werner Zang ◽  
Danilo César Silva e Sousa
Keyword(s):  
New Technology ◽  
X Ray Diffraction ◽  
Synthesis Of Nanoparticles ◽  
Research Areas ◽  
Magnetite Fe3o4 ◽  
Mineral Substance ◽  
Abundant Element ◽  
The Stability ◽  
Average Size

Nanopartículas de ferro são muito utilizadas em diversas áreas de pesquisa. O elemento químico ferro (Fe), sendo o quarto elemento mais abundante na crosta terrestre, e a substância mineral magnetita, com propriedade magnética, apresentam aplicações nas áreas industrial, ambiental, biomédica e de novas tecnologias. Este trabalho apresenta processo de síntese de nanopartículas partindo-se de sais precursores, bem como a caracterização dos produtos e as rotas para estabilizá-los. Os sais químicos precursores utilizados foram o cloreto férrico (FeCl3) e o sulfato ferroso (FeSO4) na proporção de 2:1, sob agitação por ultrassom e pH ácido. Para formação do precipitado de nanopartículas usou-se solução aquosa de hidróxido de sódio (NaOH) de pH 12. A difratometria de raio-X, mostra a presença de magnetita (Fe3O4) indicada pelos picos característicos de difração em graus 2Ө = 18° (largo), 31° (fino), 36° (bem definido), 43,4°, 45°, 53,6°, 57,7°, 63,3°. A microscopia eletrônica de transmissão mostra a morfologia dos produtos da síntese. Fatores que influenciam a estabilidade das partículas são agitação, o ajuste de pH, condições de secagem. O tamanho médio das nanopartículas de magnetitas é de aproximadamente 15 nm.   Iron nanoparticles are widely used in several research areas. The chemical element iron (Fe), being the fourth most abundant element in the earth's crust, and the mineral substance magnetite, with magnetic properties, have applications in industrial, environmental, biomedical, and new technology areas. This work presents the process of synthesis of nanoparticles starting from precursor salts, as well as the characterization of the products and the routes to stabilize them. The precursor chemical salts were ferric chloride (FeCl3) and ferrous sulfate (FeSO4) in a 2:1 ratio, under ultrasound agitation and acidic pH. For the nanoparticles growth was applied aqueous solution of sodium hydroxide (NaOH) at pH 12. X-ray diffraction shows the presence of magnetite (Fe3O4) indicated by characteristic diffraction peaks in degrees 2Ө = 18° (wide), 31° (fine), 36° (well defined), 43.4°, 45°, 53.6°, 57.7°, 63.3°. Scanning electron microscopy shows the morphology of the synthesis products. Factors that influence the stability of the particles are agitation, the pH adjustment, and the conditions of drying. The average size of the magnetite nanoparticles is approximately 15 nm.

scholarly journals STARCH MEDIATED SYNTHESIS OF HYDROXYAPATITE NANOPARTICLE FOR BIOMEDICAL APPLICATIONS

2015 ◽  
Vol 2 (1) ◽  
pp. 15-17
Author(s):  
Indira J
Keyword(s):  
Biomedical Applications ◽  
Soluble Starch ◽  
Morphological Properties ◽  
Spherical Nanoparticles ◽  
Hydroxyapatite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Average Size ◽  
Controllable Size

Hydroxyapatite (HAP) nanoparticles with uniform morphologies and controllable size have been synthesized by template directed method. The environment and eco-friendly polysaccharide soluble starch is used as a template to regulate size and shape of the nanoparticles synthesized. Structural and morphological properties of as-synthesized hydroxyapatite nanoparticles have been examined through the techniques like Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Scanning Electron Microscopy(SEM), respectively. The results indicate that the obtained particles are uniform discrete spherical nanoparticles. The average size of the hydroxyapatite nanoparticles were ranged from 45 to 60 nm.

scholarly journals Silver-Nanoparticles Embedded Pyridine-Cholesterol Xerogels as Highly Efficient Catalysts for 4-nitrophenol Reduction

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1486
Author(s):  
Ganesh Shimoga ◽  
Eun-Jae Shin ◽  
Sang-Youn Kim
Keyword(s):  
Silver Nanoparticles ◽  
Trisodium Citrate ◽  
Environmentally Benign ◽  
X Ray Diffraction ◽  
Physico Chemical ◽  
Efficient Reduction ◽  
Nitrophenol Reduction ◽  
Uv Visible ◽  
Average Size

Two xerogels made of 4-pyridyl cholesterol (PC) and silver-nanocomposites (SNCs) thereof have been studied for their efficient reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of aqueous sodium borohydride. Since in-situ silver doping will be effective in ethanol and acetone solvents with a PC gelator, two silver-loaded PC xerogels were prepared and successive SNCs were achieved by using an environmentally benign trisodium citrate dehydrate reducing agent. The formed PC xerogels and their SNCs were comprehensively investigated using different physico-chemical techniques, such as field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), powdered X-ray diffraction (XRD) and UV-Visible spectroscopy (UV-Vis). The FE-SEM results confirm that the shape of xerogel-covered silver nanoparticles (SNPs) are roughly spherical, with an average size in the range of 30–80 nm. Thermal degradation studies were analyzed via the sensitive graphical Broido’s method using a TGA technique. Both SNC-PC (SNC-PC-X1 and SNC-PC-X2) xerogels showed remarkable catalytic performances, with recyclable conversion efficiency of around 82% after the fourth consecutive run. The apparent rate constant (kapp) of SNC-PC-X1 and SNC-PC-X2 were found to be 6.120 × 10-3 sec-1 and 3.758 × 10-3 sec-1, respectively, at an ambient temperature.

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