scholarly journals Влияние ультрадиспергирования на химические сдвиги рентгеновских K-линий в оксидах меди и марганца

2020 ◽  
Vol 62 (10) ◽  
pp. 1637
Author(s):  
А.А. Набережнов ◽  
А.Е. Совестнов ◽  
Д.А. Курдюков ◽  
Э.В. Фомин ◽  
А.В. Фокин
Keyword(s):  
Pore Diameter ◽  
Oxide Nanoparticles ◽  
Chemical Bonds ◽  
Borosilicate Glasses ◽  
Average Pore ◽  
X Ray ◽  
Capillary Impregnation ◽  
Opposite Trend ◽  
Atom Increase

The results of study of shifts of X-ray Kα and Kß lines of manganese and copper obtained for CuO, MnO, Mn3O4 and MnO2 oxide nanoparticles (relative to the corresponding massive materials) are presented. Oxide nanoparticles were synthesized in the pores of borosilicate glasses with an average pore diameter of 7±1 nm from the corresponding nitrates introduced into the pores by capillary impregnation. It was found, that for nanocomposites with CuO and Mn3O4 there is a small (about ~0.1 el./atom) increase in the role of 3d electrons in the chemical bonds. On the contrary, for nanocomposites with MnO2 the role of these electrons has an opposite trend.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

Preparation and Characterization TiO2 Aerogel Fibers

2013 ◽  
Vol 743-744 ◽  
pp. 434-437
Author(s):  
Miao Lv ◽  
Guo Tong Qin ◽  
Wei Wei
Keyword(s):  
Electron Microscopy ◽  
Pore Diameter ◽  
Supercritical Drying ◽  
Mass Ratio ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Adsorption Desorption ◽  
Scanning Electron

TiO2aerogel fibers have been fabricated by electron span combined supercritical drying technique. Polyvinylpyrrolidone (PVP)/TiO2composite fibers are prepared by electrospinning PVP and TiO2precursor Ti (OC4H9)4. TiO2aerogel fibers are obtained by supercritical drying PVP/TiO2composite fibers using ethanol as media. Structural of the aerogel fibers was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2adsorption at 77 K. The effect of mass ratio of PVP/TiO2was investigated. SEM shows that pore structure of nanofibers was well developed, with the diameter of nanofibers about 2 μm. N2adsorption/desorption data show that the highest surface area of aerogel fibers reached 241.6 m2/g with the average pore diameter about 10 nm. The aerogel fibers were anatase type TiO2.

scholarly journals Synthesis of Iron Oxide Nanoparticles Using Isobutanol

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Diana Kostyukova ◽  
Yong Hee Chung
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Ammonium Hydroxide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Ferrous Chloride ◽  
X Ray ◽  
Superparamagnetic Properties

Iron oxide nanoparticles were synthesized by precipitation in isobutanol with sodium hydroxide and ammonium hydroxide. The isobutanol played a role of a surfactant in the synthesis. The nanoparticles were calcined for 100 min to 5 hours in the range of 300 to 600°C. The characterization of the samples by FTIR (Fourier-transform infrared) and XRD (X-ray diffraction) confirmed the formation ofγ-Fe2O3(maghemite) from Fe3O4(magnetite) at calcination at 300°C. The morphology and particle size were studied by SEM (scanning electron microscope). Nanoparticles in the range of 11–22 nm prepared at 0.09 M of ferrous chloride exhibited superparamagnetic properties. Nanoparticles synthesized with ferrous chloride and ammonium hydroxide at 75°C and calcined at 530°C for 2 h wereα-Fe2O3(hematite).

Synthesis and Characterization of Co/SBA-15 Catalysts

2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa
Keyword(s):  
Molecular Sieve ◽  
Pore Diameter ◽  
Mesoporous Structure ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Wet Impregnation ◽  
X Ray ◽  
Different Temperatures ◽  
Temperature Programmed

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.

Electrochemical Fabrication of Porous Interconnected Copper Foam

2021 ◽  
Vol 902 ◽  
pp. 9-14
Author(s):  
Mary Donnabelle L. Balela ◽  
Reginald E. Masirag ◽  
Francis O. Pacariem Jr. ◽  
Juicel Marie D. Taguinod
Keyword(s):  
Wall Thickness ◽  
Current Density ◽  
Pore Diameter ◽  
Average Pore Size ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Copper Foam ◽  
Electrochemical Fabrication ◽  
Cu Foam

An interconnected copper network or copper foam was successfully fabricated by electrochemical deposition using polyethylene glycol (PEG) and sodium bromide (NaBr) as additives. Both the amount of PEG and the current density were varied to obtain a Cu foam with the smallest pore diameter and wall thickness. The increasing amount of PEG resulted in a decrease in pore diameter. However, the wall thickness of the Cu network was increased. At 800 mg/L PEG and 20 mM NaBr, the average pore size of the foam was about 11.03 µm. Dendritic formation was also observed on the walls of the Cu foam. Further, higher current density resulted in increased dendritic growth. X-ray diffraction confirms that the Cu foam was spontaneously oxidized in air, leading to the formation of cuprous oxide (Cu2O).

The Structure and Porosity of Fe62-xCo10WyMexY8B20-y Alloys in the Amorphous and Crystalline States (where: Me = Mo, Nb; x = 0, 1, 2; y = 0, 1, 2)

2017 ◽  
Vol 68 (1) ◽  
pp. 22-27
Author(s):  
Marcin Nabialek ◽  
Pawel Pietrusiewicz ◽  
Michal Szota ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Andrei Victor Sandu
Keyword(s):  
Pore Diameter ◽  
Copper Plate ◽  
X Ray Diffraction ◽  
Amorphous Halo ◽  
Casting Method ◽  
Average Pore ◽  
X Ray ◽  
Crystallization Method ◽  
Injection Casting ◽  
Diffraction Patterns

The investigated crystalline and amorphous samples were obtained by crystallization of the liquid alloy on a water-cooled copper plate and by an injection-casting method, respectively. In each case, the structure of the samples was determined by examination of the obtained X-ray diffraction patterns. The diffraction patterns of samples produced by the injection casting method were characterized by a single broad peak called the amorphous halo. The samples produced by the crystallization method were shown to feature within their structure the following phases:YB2, Fe2Y, �-Fe, Co5Y, and B6Co23. Further research, performed using computer tomography, revealed the existence of pores within the samples. The crystalline-structure samples were found to feature a lower average pore diameter.

Nanostructured Ferrite Formation in Borosilicate Glass

2009 ◽  
Vol 79-82 ◽  
pp. 445-448
Author(s):  
Viorel Sandu ◽  
Stelian Popa ◽  
Iuliana Pasuk ◽  
Ionut Enculescu ◽  
Mirela Sidonia Nicolescu ◽  
...  
Keyword(s):  
Structural Transition ◽  
Borosilicate Glasses ◽  
Temperature Transition ◽  
X Ray Diffraction ◽  
Verwey Transition ◽  
X Ray ◽  
Magnetization Data ◽  
Structural And Magnetic Properties ◽  
Step Transition

We present the preparation, structural, and magnetic properties of a series of Fe-containing borosilicate glasses as a function of the ratio SiO2/Fe2O3 which is ranging from 1.49 to 2.68. The role of nucleators (Cr2O3 and P2O5) was also investigated. X-Ray diffraction has revealed the formation of magnetite as the major or unique crystalline phase. As SEM micrographs have revealed, the addition of P2O5 give rise to a finer structure as compared with Cr2O3. In addition, the same oxide decreases the temperature of structural transition with almost 100 °C. The magnetization data reveal a two step transition at low temperatures: a high temperature transition at Tv = 128 K, which we attribute to the Verwey transition, and a low temperature transition at Ts = 48 K which, most likely, is the result of change in the dynamic of the domain motion.

Abstract 38: Engineered Anisotropic Scaffolds Promote the Function of Cocultured Cardiomyocytes Derived From Human Pluripotent Stem Cells

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Maureen Wanjare ◽  
Joseph Jung-Woong Kim ◽  
Ngan Huang
Keyword(s):  
Pore Diameter ◽  
Cultured Cells ◽  
Three Dimensional ◽  
Induced Pluripotent Stem Cell ◽  
Average Pore ◽  
Cardiac Tissues ◽  
Electrospun Scaffolds ◽  
In Series ◽  
Induced Pluripotent

Since the heart is effectively an anisotropic organ in which the cardiomyocytes (CM) are locally aligned in series, it is important to engineer cardiac tissues that promote CM alignment in order to closely mimic the architecture of the native tissue, as well as better mimic the cellular composition of the heart. The objective of this study was to define the role of anisotropic extracellular matrix cues on the organization and survival of human induced pluripotent stem cell-derived CMs (hiPSC-CMs) by co-culturing hiPSC-CMs and primary endothelial cells (ECs) on parallel-aligned microfibrillar scaffolds. The hiPSC-CMs were generated from hiPSCs using small molecule Wnt pathway agonists and antagonists. Subsequently, the hiPSC-CMs were sequentially seeded on day 15 after EC attachment. We cultured monocultures and cocultures on electrospun three-dimensional (3D) scaffolds of polycaprolactone (PCL) and polyethylene oxide (PEO) polymer blends with an average fiber diameter of 14 μm. Aligned scaffolds were fabricated by stretching the randomly oriented scaffolds by 300% of the original scaffold length. Randomly oriented fibrillar scaffolds had an average pore diameter of 17 μm when compared to the 36 μm pore diameter of aligned scaffolds. Our results indicate that alignment of co-cultured cells at a 5:1 hiPSC-CMs : EC ratio was promoted by anistropic 3D electrospun scaffolds when compared to similar random 3D electrospun scaffolds. Additionally, cocultured cells on aligned fibrillar scaffolds had a mean angle of orientation of 30.8°, relative to the direction of fibrils, which was similar to that of hiPSC-CM monocultures on aligned scaffolds (32.8°). In contrast, the degree of alignment of hiPSC-CMs on randomly oriented fibrillary scaffolds was 43.4°, which suggests a non-oriented population of cells. Aligned scaffolds also produced more synchronized cardiomyocyte contraction than random scaffold orientations, although both induced spontaneous contraction frequency of ~1Hz. This study highlights the importance of nanotopographical cues and intercellular interactions in mediating the morphology and contractility of hiPSC-CMs for treatment of cardiovascular diseases such as myocardial infarction.

scholarly journals Temperature effect on the porosity of hydroxyapatite scaffolds and its use in tissue engineering

2020 ◽  
Vol 3 (4) ◽  
pp. 213-221
Author(s):  
Vareska Lucero Zarate-Córdova ◽  
Mercedes Teresita Oropeza-Guzmán ◽  
Eduardo Alberto López-Maldonado ◽  
Ana Leticia Iglesias ◽  
Theodore Ng ◽  
...  
Keyword(s):  
Temperature Effect ◽  
Pore Diameter ◽  
Porous Scaffolds ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Raman Analysis ◽  
X Ray ◽  
Salt Leaching ◽  
Bone Replacement ◽  
Different Temperatures

The search for a suitable bone replacement is of great importance due to the difficulty to use autologous transplants. Hence, the objective of this work is to compare the temperature effect on the porosity and average pore diameter of hydroxyapatite porous scaffolds fabricated by the salt leaching method.  Hydroxyapatite porous scaffolds fabricated by the salt leaching technique were sintered from ~150 to 1000 °C. Synthesized hydroxyapatite was assessed by X-ray diffraction (XRD). Zeta potential at different temperatures was evaluated. Specimens were characterized using scanning electron microscopy (SEM) and Raman analysis. The results showed that significant porosity (57%) and pore size (49 µm) occurred with a thermal treatment above ~ 850 °C for scaffolds that were pre-sintered at 1050 °C.

scholarly journals The Role of Cations in Resorcinol–Formaldehyde Gel Textural Characteristics

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 60
Author(s):  
Stewart J. Taylor ◽  
Liu Yang ◽  
Ashleigh J. Fletcher
Keyword(s):  
Pore Size ◽  
Pore Diameter ◽  
Textural Properties ◽  
Average Pore ◽  
Salting Out ◽  
Resorcinol Formaldehyde ◽  
Catalyst Composition ◽  
Solids Content ◽  
Insight Into

The production of resorcinol–formaldehyde xerogels has yielded insight into the gelation processes underpinning their structures. In this work, the role of the cation species from the catalyst is probed by studying the simultaneous addition of sodium carbonate and calcium carbonate to a resorcinol–formaldehyde mixture. Twenty-eight xerogels were prepared by varying the solids content, catalyst concentration, and catalyst composition, and each was analysed for its textural properties, including the surface area and average pore diameter. The results indicate that the role of the cation is linked to the stabilisation of the clusters formed within the system, and that the Group II catalyst causes the salting out of the oligomers, resulting in fewer, larger clusters, hence, an increase in pore size and a broadening of the pore size distribution. The results provide insight into how these systems can be further controlled to create tailored porous materials for a range of applications.

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