Chemical,morphological, structural,optical, and magnetic properties of Zn<Subscript>1−x</Subscript>Nd<Subscript>x</Subscript>O nanoparticles

In the present investigation, we made an endeavor to fabricate the ZnO nanoparticles and achieved the tunable properties with Nd doping. The Nd-doped ZnO nanoparticles were characterized via X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS) studies that confirmed the successful doping of Nd ions in the ZnO crystal lattice without amending its hexagonal phase. The particle morphology revealed nearly spherical particles with uniform size distribution. The band gap of these samples was determined using diffuse-reflectance spectra (DRS) and was found to vary from 3.17 to 3.21 eV with increasing Nd concentration. A broad and intense emission band at 1083 nm for Nd doped ZnO nanoparticles is observed and is assigned to corresponding emission transition ⁴F_3/2?→?⁴I_11/2 of Nd³⁺ ions. Furthermore, the magnetic studies indicate that the Nd doping altered the magnetic behavior of nanocrystalline ZnO particles from diamagnetic to ferromagnetic at 300 K and that the magnetization of these samples decreased with increasing Nd concentration. The tunable optical band gap as well as room-temperature ferromagnetism of these samples may find applications in both optoelectronics and spintronics.     

Preparation,characterization, conductivity and thermal expansion studies of Ca<Subscript>0.5</Subscript>SbMP<Subscript>3</Subscript>O<Subscript>12</Subscript> (M = Al,Fe, Cr)

Nasicon type compounds of general formula Ca_0.5SbMP₃O₁₂ (M = Al, Fe, Cr) are prepared by solid-state method. All the compounds crystallize in hexagonal lattice with space group. The IR spectra show characteristic PO₄ vibrations. Conductivity studies indicate the presence of charged defects. The Cole-Cole plots of impedance are semicircles between 150 and 350 °C. The thermal expansion of these samples is studied in the temperature range 25–500 °C.     

Ba<Subscript>1−x</Subscript>La<Subscript>x</Subscript>Fe<Subscript>12</Subscript>O<Subscript>19</Subscript> (x = 0.0, 0.2, 0.4, 0.6) hollow microspheres: material parameters,magnetic and microwave absorbing properties

Ba_1?xLa_xFe₁₂O₁₉ (x = 0.0, 0.2, 0.4, 0.6) hollow ceramic microspheres (HCMs) have been prepared by combining self-reactive quenching method with heat treatment. Their material parameters, magnetic and microwave absorbing properties were investigated. It was observed that after doping of lanthanum, the material parameters showed a little change except hexagonal crystal disappearing. And the magnetic properties of HCMs were decided by lanthanum content and material parameters. With the lathanum increases from 0.0 to 0.6, the saturation magnetization (Ms) values initially increased, and then decreased sharply to a minimum value, and increased again, moreover, the coercive force (Hc) values were reduced first, and then increased, and decrease to a minimum value. Absorbing properties tests indicate that after La³⁺-doped, at 2 mm thickness, the effective absorbing band (<?10 dB) was reduced to 4.7, 5 and 4.4 GHz, respectively, the minimum reflectance would decrease in low substituted level (x ≤ 0.4) and increase in high level (x = 0.6), and the frequency shifts to low frequency with the increasing of doping content. In 1.5–3 mm range, with the increasing of thickness, the absorption peak of Ba_1?xLa_xFe₁₂O₁₉ (x = 0.2, 0.4, 0.6) HCMs shifts to low frequency and the absorption intensity increases, the effective absorbing band can up to 10, 8.1 and 8 GHz, respectively.     

First-principles calculations of crystal structure,electronic structure and optical properties of Ba<Subscript>2</Subscript>RETaO<Subscript>6</Subscript> (RE = Y,La, Pr,Sm, Gd)

The crystal structure, electronic structure and optical properties of Ba₂RETaO₆ (RE?=?Y, La, Pr, Sm, Gd) have been studied by first-principles calculation. The calculated lattice parameters are in good agreement with the previously reported values. With increasing the atomic number of RE (i.e., the number of 4f electrons), the energy level of RE 4f bands becomes lower continuously. The relationship between the electronic structure and optical properties is explored based on first-principles calculation. The electron transitions between O 2p states, RE 4f states and Ta 5d states have a key effect on optical properties such as dielectric function, refractive index, absorption coefficient and reflectivity. The phase structures have great influence on the optical properties of Ba₂SmTaO₆ and Ba₂GdTaO₆, and the big variation of reflectivity induced from phase transition makes them have potential applications in the infrared radiation protection area.     

Structural,elastic, electronic,and optical properties of defect-chalcopyrite structure CdGa<Subscript>2</Subscript><Emphasis Type="Italic">X</Emphasis><Subscript>4</Subscript> (<Emphasis Type="Italic">X</Emphasis> = S,Se) compounds

First-principles calculations were performed to investigate the elastic, electronic, and optical properties of defect-chalcopyrite (DC) structure CdGa₂ X ₄ (X = S, Se) compounds. The present calculations shown that the DC structure CdGa₂ X ₄ (X = S, Se) compounds are mechanically stable and have similar electronic structures. Optical properties including the dielectric function, optical reflectivity, refractive index and electron energy loss, are discussed for radiation up to 22 eV, and present calculations reveal a weak anisotropy in CdGa₂S₄ and CdGa₂Se₄ compounds.     

NaScMo<Subscript>2</Subscript>O<Subscript>8</Subscript>:RE<Superscript>3+</Superscript> (RE = Tb,Eu, Tb/Eu,Yb/Er,Yb/Ho) phosphors: hydrothermal synthesis,energy transfer and multicolor tunable luminescence

NaScMo₂O₈:RE³⁺ (RE = Tb, Eu, Tb/Eu, Yb/Er, Yb/Ho) phosphors were successfully synthesized by surfactant-free hydrothermal method and post-calcination treatment. The energy transfer (ET) of MoO₄ ^2? → Tb³⁺ → Eu³⁺ was proved by photoluminescence spectra and decay features. Multicolor emissions (green → yellow → red) were obtained by adjusting the ratio of Tb³⁺/Eu³⁺ upon excitation into the MoO₄ ^2? at 292 nm. The ET of Tb³⁺ → Eu³⁺ was demonstrated to be a resonant type via a dipole–dipole mechanism, and the crystal distance (R _c) was calculated by the quenching concentration method. Under 980 nm excitation, the emission of NaScMo₂O₈:RE³⁺ (RE = Yb/Er, Yb/Ho) showed strong green (Yb³⁺/Er³⁺: ⁴S_3/2, ²H_11/2 → ⁴I_15/2; Yb³⁺/Ho³⁺: ⁵S₂ → ⁵I₈) luminescence, respectively. Moreover, the doping concentration of the Yb³⁺ has been optimized under a fixed concentration of Er³⁺ and Ho³⁺, respectively. The NaScMo₂O₈:RE³⁺ phosphors have potential applications for color displays and light-emitting devices due to a variety of luminous colors.     

Phase formation,microstructure, and ionic conductivity of (La,Sr)(Ga,Ge,Mg)O<Subscript>3–<Emphasis Type="Italic">d</Emphasis></Subscript> ceramics

We have prepared ceramic (La_0.8Sr_0.2){[Ga_0.8–x (Ge_0.5Mg_0.5) _x ]Mg_0.2}O_3–d (LSGGM) (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8) samples by solid-state reactions and studied their phase composition, structure, microstructure, and electrical conductivity. Phase-pure solid solutions have been obtained upon substitution of germanium and magnesium cations for up to 20 at % of the gallium cations. The modified samples have been shown to have high density, optimal microstructure, densely packed grains, and high electrical conductivity at high temperatures.     

Synthesis and properties of Ca<Subscript>2.8</Subscript>Ln<Subscript>0.2</Subscript>Co<Subscript>4</Subscript>O<Subscript>9 + δ</Subscript> (Ln = La,Nd, Sm,Tb-Er) solid solutions

Ca_2.8Ln_0.2Co₄O_{9 + δ} (Ln = La, Nd, Sm, Tb-Er) solid solutions have been prepared via a citrate route and their structural parameters have been determined. Their thermal expansion, thermoelectric power, thermal conductivity, and electrical conductivity have been measured above room temperature. The results demonstrate that all of the materials obtained are p-type semiconductors. Their unit-cell parameters decrease with a decrease in the ionic radius of the Ln³⁺ cation substituted for Ca²⁺, and their thermoelectric power increases with an increase in the number of f electrons of the Ln³⁺ cation. We have determined the electron and phonon contributions to the thermal conductivity of the materials and evaluated the thermoelectric power factor and thermoelectric figure of merit of the oxide ceramics. The highest thermoelectric power factors are offered by the Ca_2.8Tb_0.2Co₄O_{9 + δ} and Ca_2.8Er_0.2Co₄O_{9 + δ} solid solutions: 0.27 and 0.29 mW/(m K²), respectively, at T = 1100 K.     

Synthesis,structure, and physicochemical properties of compounds Pb(B<Superscript>V</Superscript>UO<Subscript>6</Subscript>)<Subscript>2</Subscript> ⋅ <Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O (B<Superscript>V</Superscript> = P,As, V)

Compounds Pb(B^VUO₆)₂ nH₂O (B^V = P, As, V) were synthesized and studied by X-ray diffraction, IR spectroscopy, thermal analysis, and reaction calorimetry. The standard enthalpies and Gibbs energies of formation of the compounds at T = 298 K were determined, and processes involving these compounds were quantitatively characterized.Translated from Radiokhimiya, Vol. 46, No. 5, 2004, pp. 412–417.Original Russian Text Copyright © 2004 by Suleimanov, Chernorukov, Golubev.     

Synthesis and magnetic properties of M<Subscript>0.08</Subscript>Ti<Subscript>0.91</Subscript>V<Subscript>0.09</Subscript>O<Subscript>2 + δ</Subscript> · <Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O (M = Cr,Mn, Fe,Co, Ni) nanopowders

Using sol-gel synthesis and ion exchange, we have prepared titanium vanadium oxide nanopowders doped with transition-metal ions: M_0.08Ti_0.91V_0.09O_{2 + δ} · nH₂O with M = Cr, Mn, Fe, Co, and Ni. The valence state of the ions in the nanopowders and their morphology and structure have been studied by scanning electron microscopy, X-ray diffraction, IR spectroscopy, and X-ray photoelectron spectroscopy. The M _x Ti_0.91V_0.09O_{2 + δ} · nH₂O oxides dried in air or calcined at 400°C in air are shown to be paramagnets. Vacuum annealing of Co_0.08Ti_0.91V_0.09O_{2 + δ} · nH₂O at 700°C gives rise to a significant ferromagnetic contribution.     

Comparative Studies of Microwave and Sol–Gel-Assisted Combustion Methods of NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> Nanostructures: Synthesis,Structural, Morphological,Opto-magnetic,and Antimicrobial Activity

Nickel ferrite NiFe₂O₄ nanoparticles (NPs) were successfully synthesized by using nickel nitrate, ferric nitrate, citric acid, and ethyl cellulose as a surfactant by a simple sol–gel-assisted combustion method (SACM) and microwave-assisted combustion method (MACM). Structural, morphological, optical, and magnetic properties of the obtained powder were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL) spectroscopy, and vibrating sample magnetometry (VSM). XRD results show that the resultant powder was pure crystalline with cubic structure. The average crystalline size was found to be 18.8 and 10.2 nm synthesized by SACM and MACM, respectively. FT-IR spectra indicate the type of bonds between Ni–O and Fe–O (metal and oxygen). SEM images show that the morphology of the powder consists of well-defined structure. VSM results showed a ferromagnetic behavior of the sample. Antimicrobial activity of NiFe₂O₄ nanoparticles was performed. Both sample 1 (SACM) and sample 2 (MACM) show good inhibition in the zone 100 μg/ml. While comparing, sample 2 shows high inhibition than sample 1.     

Inter- and Intra-granular Interactions of REBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7−<Emphasis Type="Italic">δ</Emphasis></Subscript>, RE: Eu,Gd, Ho and Er

Here, the superconducting and AC/DC magnetic properties of REBa₂Cu₃O_7−δ (RE: Eu, Gd, Ho and Er) are investigated in order to understand the inter-granular and intra-granular behavior of these compounds. These compounds were prepared by standard solid-state reaction route. ErBa₂Cu₃O_7−δ (Er-123) and HoBa₂Cu₃O_7−δ (Ho-123) (consisting of heavier rare earth) show higher orthorhombic splitting in their XRD patterns than those observed for EuBa₂Cu₃O_7−δ (Eu-123) and GdBa₂Cu₃O_7−δ (Gd-123) (consisting of lighter rare earth). Even though Eu, Gd, Ho and Er are magnetic elements, substitution of these at Y site in Y-123 does not change the superconducting transition temperature (T _c). Er-123 and Ho-123 exhibit very sharp superconducting transition while Eu-123 and Gd-123 exhibit relatively broad transition with little hump at the lower part of transition close to the long-range superconducting state with zero resistance. In addition to that, Eu-123 and Gd-123 show relatively higher normal state resistivity than those of Er-123 and Ho-123. The AC susceptibility measurements reveal that these compounds possess different strength of inter-granular couplings. The hump in the superconducting transition of Eu and Gd is not due to the lack of inter-grain couplings in these samples because of having better grain connectivity in the samples as compared to other rare earth elements in REBa₂Cu₃O_7−δ system. Though intra-grain peak is insensitive to the applied magnetic field, inter-grain peak is sensitive to the applied magnetic field.     

Chemical interaction of InAs,InSb, GaAs,and GaSb crystals with aqueous (NH<Subscript>4</Subscript>)<Subscript>2</Subscript>Cr<Subscript>2</Subscript>O<Subscript>7</Subscript>–HBr solutions

We have studied the nature and kinetics of the chemical interaction of InAs, InSb, GaAs, and GaSb crystals with aqueous (NH₄)₂Cr₂O₇–HBr solutions. The dissolution rate of the crystals has been measured as a function of etchant composition, solution stirring rate, and temperature. The results demonstrate that the dissolution rate of the semiconductors is diffusion-limited. We have determined the composition ranges of polishing solutions, optimized their compositions, and found conditions for the dynamic chemical polishing of the semiconductors. Ultrasmooth polished semiconductor surfaces have been obtained, with R _a ≈ 1 nm.     

Bonfils & Son,Egypt, Greece and the Levant; 1867–1894

Abstract

Félix Bonfils was born in Saint Hippolyte du Fort, France, on 6th March 1831. Little is known of his early life. Family sources indicate he began his professional career by operating his own printing press¹. On becoming interested in photography, he produced photographs using the heliogravure process invented by Niépce. In due course, he adopted the collodion wet-plate process, with all its well-known complications and encumbrances. For the landscape photographer lie was to become, the task of moving his equipment from place to place must have been formidable, especially in countries where roads and transport were meagre.     

Modelling,structural, thermal,optical and vibrational studies of a new organic–inorganic hybrid material (C<Subscript>5</Subscript>H<Subscript>16</Subscript>N<Subscript>2</Subscript>)Cd<Subscript>1.5</Subscript>Cl<Subscript>5</Subscript>

Chemical preparation, theoretical calculations, X-ray single-crystal diffraction, thermal analysis, electrochemical measurements, IR, Raman and UV spectroscopic investigations of a novel organic–inorganic hybrid material (C₅H₁₆N₂)Cd_1.5Cl₅ are described. The structure provides a new interesting example of infinite inorganic chains of [Cd_1.5Cl₅]\(_{\mathbf {n}}^{\boldsymbol {2\mathrm {n}-}}\) following the a crystallographic direction. The [Cd_1.5Cl₅]^2? anions are interconnected by N–H ? Cl hydrogen bonds. The Hirshfeld surface and associated fingerprint plots of the compound are presented to explore the nature of intermolecular interactions and their relative contributions in building the solid-state architecture. IR and Raman spectra are reported and discussed on the basis of group theoretical analysis and quantum chemical density functional theory (DFT) calculation. The molecular HOMO–LUMO compositions and their respective energy gaps are also drawn to explain the activity of our compound. Thermal analysis reveals the anhydrous character of the compound.     

Chemical interaction of InAs,InSb, GaAs,and GaSb with (NH<Subscript>4</Subscript>)<Subscript>2</Subscript>Cr<Subscript>2</Subscript>O<Subscript>7</Subscript>–HBr–C<Subscript>4</Subscript>H<Subscript>6</Subscript>O<Subscript>6</Subscript> etching solutions

This paper presents results on the kinetics and mechanism of the physicochemical interaction of InAs, InSb, GaAs, and GaSb semiconductor surfaces with (NH₄)₂Cr₂O₇–HBr–C₄H₆O₆ etching solutions under reproducible hydrodynamic conditions in the case of laminar etchant flow over a substrate. We have identified regions of polishing and nonpolishing solutions and evaluated the apparent activation energy of the process. The surface morphology of the crystals has been examined by microstructural analysis after chemical etching. The results demonstrate that the presence of C₄H₆O₆ in etchants helps to reduce the overall reaction rate and extend the region of polishing solutions.     

Crystal structure of compounds CsA<Superscript>V</Superscript>A′<Superscript>VI</Superscript>O<Subscript>6</Subscript> (A<Superscript>V</Superscript> = Sb,Ta; A′<Superscript>VI</Superscript> = W,U)

Compounds CsA^VA′^VIO₆ (A^V = Sb, Ta; A′^VI = W, U) were synthesized by high-temperature solidphase reactions. The crystal structures of the compounds were refined by the Rietveld method (space group Fd \(\bar 3\) m).     

Crystal growth,X-ray diffraction characterization,and Mössbauer spectroscopy of FeIn<Subscript>2</Subscript>S<Subscript>4</Subscript>-In<Subscript>2</Subscript>S<Subscript>3</Subscript> solid solutions

Crystals of (FeIn₂S₄)_{1 ? x} (In₂S₃) _x solid solutions consisting of large blocks have been grown by directional solidification (horizontal Bridgman process). FeIn₂S₄, In₂S₃, and the solid solutions are shown to crystallize in the spinel structure. The composition dependence of their unit-cell parameter a follows Vegard's law. The local states of the Fe ions in the solid solutions have been studied by Mössbauer spectroscopy in a transmission geometry.     

Extraction,detection, and profiling of serum biomarkers using designed Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@SiO<Subscript>2</Subscript>@HA core–shell particles

Serum biomarkers in the form of proteins (e.g. cluster of differentiation-44 (CD44)) have been demonstrated to have high clinical sensitivity and specificity for disease diagnosis and prognosis. Owing to the high sample complexity and low molecular abundance in serum, the detection and profiling of biomarkers rely on efficient extraction by materials and devices, mostly using immunoassays via antibody-antigen recognition. Antibody-free approaches are promising and need to be developed for real-case applications in serum to address the limitations of antibody-based techniques in terms of robustness, expense, and throughput. In this work, we demonstrated a novel approach using hyaluronic acid (HA)-modified materials/devices for the extraction, detection, and profiling of serum biomarkers via ligand-protein interactions. We constructed Fe₃O₄@SiO₂@HA particles with different sizes through layer-by-layer assembly and for the first time applied HA-functionalized particles in the facile extraction and sequence identification of CD44 in serum by mass spectrometry. We also first validated HA-CD44 binding through electrochemical sensing using HA-modified electrodes in both standard solutions and diluted serum samples, achieving a detection limit of ～0.6 ng/mL and a linear response range from 1 ng/mL to 10 μg/mL. Furthermore, we performed profiling of HA-binding serum proteome, providing a new preliminary benchmark for the construction of future databases, and we investigated selected surface chemistries of particles for the capture of proteins in serum. Our work not only resulted in the development of a platform technology for CD44 extraction/detection and HA-binding proteome identification, but also guided the design of ligand affinity-based approaches for antibody-free analysis of serum biomarkers towards diagnostic applications.

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