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Semiconductor nanophosphors have smart technological applications in optoelectronic devices and in nanomedicine. Here we report the synthesis of Calcium sulfide nanophosphors by wet chemical method using Triethanolamine (TEOA) as capping agent. The structural characterization of the prepared nanoparticles was done using X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The XRD pattern confirmed the cubic CaS phase with an average grain size of 21 nm of the formed samples. From TEM images, the TEOA capped nanoparticles were found to have a spherical morphology with diameter in the range 5–15 nm. The optical studies of the capped nanoparticles were carried out using Photoluminescence spectroscopy and UV–vis absorption spectroscopy. We obtained a highly intense blue emission on exciting the TEOA capped nanoparticles at 318 nm which was found to be greater than the luminescence intensity of uncapped CaS nanoparticles. The optical band gap of the capped nanoparticles was estimated from the Diffuse Reflectance Spectra and an increase in bandgap was observed which can be explained on the basis of quantum size effect. Thermogravimetric analysis and Fourier Transform Infrared Spectra analysis confirmed the presence of capping agent in the synthesized CaS nanoparticles. [ABSTRACT FROM AUTHOR]

Cerium doped zinc oxide (2 at. %) aerogels were synthesized in supercritical methanol and different supercritical mixture solvents (methanol-acetone and methanol-ethanol). The as-elaborated samples were analyzed without any additional heat or chemical treatments by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption, photoluminescence (PL) and TGA techniques. The XRD results show that drying in solvents mixture enhances the crystalline quality and acts as a compression agent by exerting stress on the lattice parameters. SEM images demonstrate that the agglomeration rate of aerogel particles decreases when solvents mixture is used. TGA measurements showed the high purity of the samples. FTIR results showed a shift of Zn O bond indicating that supercritical solvent influences the number of Ce O Zn bonds at the surface of the crystallites. UV–vis characterization demonstrates that a band-to-band transition (3.34 eV) is observed only in the spectrum of the aerogel synthesized in supercritical acetone. The photoluminescence (PL) spectra exhibited different optical properties of the aerogels in violet-blue-green wavelengths region (350–530 nm). A blue-green emission located at 485 nm is observed only in methanol and acetone. The intensity of this band is sensitive to the supercritical organic solvent. [ABSTRACT FROM AUTHOR]

Electrochemical promotion of catalysis (EPOC) is a general phenomenon of modifying the catalytic activity of a metal or metal oxide in contact with a solid electrolyte by means of current or potential application. In this work, the free-standing (unsupported) platinum and ruthenium oxide nanoparticles (NPs) (2 nm average size) in contact with yttria-stabilized zirconia (YSZ) solid-electrolyte were electrochemically promoted under galvanostatic and potentiostatic conditions for ethylene oxidation reaction. The enhancement ratio of 1.8 and 1.5 was obtained for Pt and RuO 2 NPs, respectively in potentiostatic conditions at 350 °C. The apparent Faradaic efficiency, Λ , was as high as 400 at 250 °C and decreased as the reaction temperature increased. Similar degrees of promotion were achieved under open circuit by dispersing nanoparticles on CeO 2 , TiO 2 and YSZ supports (1 wt.% metal loading). The results showed the functional equivalence of EPOC and MSI with Pt and RuO 2 NPs. This finding is of considerable value for elucidation of the mechanism of MSI and EPOC, as well as for potential practical implementation of EPOC in industrial catalytic processes that use highly dispersed nanoparticle catalysts. [ABSTRACT FROM AUTHOR]

Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain 113Cd spectra from CdTe-COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium-rich surface. [ABSTRACT FROM AUTHOR]

Monoclinic HfO2 nanoparticles with nominal diameters of 9, 30, and 45 nm are characterized using transmission and reflection spectroscopy from the mid- to far-infrared. Phonon modes are identified in the measured spectra and agree with previously reported values in HfO2 thin films and density functional perturbation theory calculations. An anomaly in both reflection and transmission is observed at 556 cm-1that is not attributed to the optical phonon modes. Numerical models predict a localized surface phonon polariton mode near this frequency, and we attribute the anomaly to coupling to this surface mode. The results of this work suggest that HfO2 nanoparticles could enable engineered optical properties in new mid- and far-infrared materials and devices. [ABSTRACT FROM AUTHOR]

Magnetic core–shell nanoparticles (CSNs) have potential applications in spintronic devices, drug delivery systems, and magnetic random access memory. By use of our hydrothermal nano-phase epitaxy method, we have accomplished synthesis of novel, well-ordered α-Cr2O3@α-Mn0.35Cr1.65O2.94 inverted CSNs. XRD and TEM analyses show a core–shell structure with corundum phase throughout the core and shell with a minimal amount of interface defects. TEM-EDX and XPS data show Mn having the +2 oxidation state in the shell of the CSNs. Magnetization measurements at 5 K show a weak coercivity (HC) value of 8 Oe and an exchange bias field (HE) of 293 Oe. Ab initio calculations show that Mn incorporation in α-Cr2O3 results in narrowing of the energy band gap, substantiated by UV–Vis measurements, and half metallic behavior in case of Mn(III) substitution. Our calculations substantiate that Mn substitution in α-Cr2O3 results in a combination of antiferromagnetic and weak ferrimagnetic character of our CSNs. [ABSTRACT FROM PUBLISHER]

Two shapes of TiO2 nanomaterial will largely affect the catalytic activity. TiO2 nanoparticles (NPs) and TiO2 nanofibers (NFs) were used to investigate the effect of shape on catalytic activities and get the optimum shape of catalysis. Electrochemical behaviors of two modified electrodes by TiO2 nanomaterial were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. Various electrochemical parameters such as electrode surface area and electron-transfer rate constant were also studied and calculated in the aqueous solution. Results showed that the response of NF is better than NP for electrooxidation of hydroquinone (HQ). The different electrochemical response of TiO2 is related to the various morphological structures, so controlling the shape and structure of nanomaterial is very important factor which is because of the powerful correlation between these parameters and their optical, catalytic and electrical properties. [ABSTRACT FROM AUTHOR]

A range of catalytic samples made by extractive-pyrolytic method (EPM) and based on nickel and palladium nanoparticles supported on inorganic supports such as activated carbon, silica, alumina and aluminium hydroxide oxide were tested in the reaction of ozone decomposition. Aluminum oxides and oxyhydroxides occur in numerous crystallographic forms which exhibit different surface properties. The properties of the catalysts were confirmed by using various characterization techniques as BET, XRD, EPR and TEM. The EPM method allows small amounts of noble metals with particle size ranging from several nanometers to several tens of nanometers to be affixed onto the surface of the support. It was found that all treated Ni/Pd catalytic samples were active in the ozone decomposition reaction but the maximum conversion degree (more than 90 %) was achieved using aluminium hydroxide oxidesupported Ni/Pd system. [ABSTRACT FROM AUTHOR]

In this study the Mn 1–2x Zr x Fe 2−y Ni y O 4 nanoparticles fabricated by co-precipitation technique were investigated. Thermo-gravimetric analysis (TGA) exhibited the annealing temperature of the nanoparticles ~990 °C. Cubic spinel structure of Mn 1–2x Zr x Fe 2−y Ni y O 4 nanoparticles was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. Crystallite size was calculated by XRD data and found in the range of 32–58 nm. Photocatalytic activity of Mn 0.92 Zr 0.04 Fe 1.88 Ni 0.12 O 4 /graphene nanocomposites was tested by degrading methylene blue (MB) under visible light irradiation. The MB was almost completely degraded in the presence of Mn 0.92 Zr 0.04 Fe 1.88 Ni 0.12 O 4 -graphene nanocomposites under visible light irradiation. Dielectric parameters were also investigated in the frequency range 1×10 6 –3×10 9 Hz. An overall decrease in the values of dielectric constant, dielectric loss and tangent loss was observed on account of the substitution of Zr and Ni with Mn and Fe cations. [ABSTRACT FROM AUTHOR]

The kinetics and mechanism of the formation of silver nanoparticles by reduction with arabinose are studied spectrophotometrically in aqueous and micellar media at different temperatures. The reaction was carried out under pseudo-first-order condition by taking the [arabinose] >10-fold the [Ag+]. The rate of reaction increases with increasing in the [OH-]. A mechanism of the reaction between silver ion and arabinose was proposed and the rate equation derived from the mechanism was consistent with experimental rate. Cetyltrimethylammoniuom bromide (CTAB) as capping agent stabilised the formed silver sol. The formation of silver nanoparticles by this method gave an easy and viable strategy for the obtained silver sols with well controlled shape and size. Enthalpy and entropy of activation were calculated. The particle size of silver sols is characterised by transmission electron microscopic (TEM), physicochemical and spectroscopic methods. [ABSTRACT FROM AUTHOR]

Heat-induced radiolabeling (HIR) yielded 89Zr-Feraheme (FH) nanoparticles (NPs) that were used to determine NP pharmacokinetics (PK) by positron emission tomography (PET). Standard uptake values indicated a fast hepatic uptake that corresponded to blood clearance, and a second, slow uptake process by lymph nodes and spleen. By cytometry, NPs were internalized by circulating monocytes and monocytes in vitro. Using an IV injection of HIR 89Zr-FH (rather than in vitro cell labeling), PET/PK provided a view of monocyte trafficking, a key component of the immune response. [ABSTRACT FROM AUTHOR]

The development of high performance uncooled infrared (IR) detection and imaging systems will greatly expand the application of IR technology in broad areas such as transportation, environmental monitoring, and medical care. Inspired by the superior IR detection capability of beetle Melanophila acuminata, we explored the potential use of hydrogel nanoparticles (NPs) in uncooled IR detection system. In the system, the absorption of the incoming IR radiation by the temperature-sensitive hydrogel NPs, together with water, induces the volume change of the hydrogel NPs, similar to the volume change of the biofluid inside the sensillae receptors in M. acuminata caused by the IR radiation. This volume change results in the change of optical readout (transmittance in this study) in visible range and provides the sensitive detection of the IR radiation. In this work, poly(N-isopropylacrylamide-co-acrylic acid) (poly(NIPAM-co-AAc)) copolymer NPs with different sizes were synthesized and their IR sensing performances were studied in detail. The correlation between the NP size and concentration and the IR sensing property was also discussed in the paper. This work helps enhance the understanding of the response of hydrogel NPs under IR radiation, and offers a potential material system for uncooled IR detection that is inspired by M. acuminata. The direct use of transmittance of the NP solution as the readout for IR detection also provides a simple and sensitive IR detection approach for low cost and portable industrial applications. [ABSTRACT FROM AUTHOR]

The possibility of using mechanical milling for the synthesis of uncarbonised coconut shell nanoparticles (UCSNPs) has been investigated. UCSNPs were synthesized from discarded coconut shells (CSs) using top down approach. The sundried CSs were crushed, ground and then sieved using hammer crusher, a two disc grinder and set of sieves with shine shaker respectively. The CS powders retained in the pan below 37 µm sized sieve were milled for 70 hours to obtain UCSNPS. Samples for analysis were taken at 16 and 70 hours. UCSNPs were analyzed using transmission electron microscope (TEM), scanning electron microscope (SEM) with attached EDS and Gwyddion software. Samples of UCSNPs obtained at 16 and 70hours show that the deep brown colour of the initial CS powder became fading as the milling hour increased. The size determination from TEM image revealed spherical particles with an average size of 18.23 nm for UCSNPs obtained at 70 hour milling. The EDS spectrographs revealed an increase in the carbon counts with increased milling hours. This is attributable to dryness of the CS powders by the heat generated during the milling process due to absorption of kinetic energy by the CS powders from the milling balls. SEM micrographs revealed UCSNPs in agglomerated networks. The SEM micrograph/Gyweddion particles size determination showed average particles of 170.5 ±3 and 104.9 ±4.1 nm for UCSNPs obtained at 16 and 70 hours respectively. Therefore, production of UCSNPs through mechanical milling using mixture of ceramic balls of different sizes has been established especially when the particles of the sourced/initial CS powders falls below 37 μm. [ABSTRACT FROM AUTHOR]

A new liquid–liquid system, employing dimethyl sulfoxide and the mixture of oleyl amine and oleic acid as separate solvents, inorganic lead salt as lead source, and sulfide as sulfur source has been developed to synthesize PbS nanoparticles with a narrow size distribution. The process can be conducted under mild conditions. The obtained PbS nanoparticles exhibit high crystallinity and uniformity. The initial Pb/S molar ratio of precursor has great effect on the particle size and optical properties of product. Larger proportion of sulfur precursor, which results in the larger particle size, is more likely to restraint crystal nucleation, rather than promote crystal growth. [ABSTRACT FROM AUTHOR]

A comparative, temperature-dependent (80-500 K at 5 K intervals), micro-Raman spectroscopic study of 300 and 50 nm diameter ceramic BaTiO3 nanoparticles was carried out with the purpose of elucidating the nanoparticle size effect on the temperature dependence of the polar and non-polar phonons. A method for calibrating Raman intensities, along with an iterative spectral fitting algorithm, is proposed for concurrent Raman band position and intensity analysis, increasing the analytical abilities of single temperature point Raman spectroscopy. The 300 nm particles exhibit all three phase transitions, whereas the 50 nm particles do not show evidence of these phase transitions in the same temperature range. The Curie temperature appears to be a phonon converging point, irrespective of the phonon symmetry. An attempt was made to qualitatively relate the temperature-dependent Raman spectra to complimentary non-spectroscopic methods, such as heat capacity and X-ray diffraction studies. The study proves that the temperature-dependent behavior of the polar phonon, 265 cm−1, can be utilized as a sensitive phase transition probe. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Persistent luminescence nanoparticles (PLNPs) hold great promise for the detection and imaging of biomolecules. Herein, we have demonstrated a novel nanoprobe, based on the manganese dioxide (MnO2)-modified PLNPs, that can detect and image glutathione in living cells and in vivo. The persistent luminescence of the PLNPs can be efficiently quenched by the MnO2 nanosheets. In the presence of glutathione (GSH), MnO2 was reduced to Mn2+ and the luminescence of PLNPs can be restored. The persistent luminescence property can allow detection and imaging without external excitation and avoid the background noise originating from the in situ excitation. This strategy can offer a promising platform for detection and imaging of reactive species in living cells or in vivo. [ABSTRACT FROM AUTHOR]

High-priority industrial nanomaterials like SiO2, TiO2, and Ag are being characterized on a systematic basis within the framework of the EU FP7 research project Nano Valid. Silica nanoparticles from an industrial source have been analyzed by Auger electron spectroscopy. Point, line, and map spectra were collected. Material specific and methodological aspects causing the special course of Auger line scan signals will be discussed. [ABSTRACT FROM AUTHOR]

Sensitive and accurate characterization of nanoparticle size in aqueousmatrices at environmentally relevant concentrations is still challenging for current nano-analysis techniques. Single particle inductively coupled plasma mass spectrometry (spICP-MS) is an emerging method to characterize the size distribution of nanoparticles and determine their concentrations. Herein for the first time the K-means clustering algorithm is applied to signal processing of spICP-MS raw data. Compared with currently used data processing approaches, the K-means algorithm improved discrimination of particle signals from background signals and provides a sophisticated, statistically based method to quantitatively resolve different size groups contained within a nanoparticle suspension. In tests with commercial Au nanoparticles (AuNPs), spICP-MS with the K-means clustering algorithm can quantitatively discriminate secondary "impurity-size nanoparticles," present at fractions of less than 2% by mass, from primary-size nanoparticles with the minimum resolvable size difference between the primary and secondary nanoparticles at ~20 nm. AuNP mixtures in which 80 nm particles act as the "primary size group" and 20 nm, 50 nm, or 100 nm particles act as the "impurity size group" were analyzed by spICP-MS, which reliably measured percentages of secondary impurity-size nanoparticles that are consistent with the expected experimentally determined values. Compared with dynamic light scattering (DLS), spICP-MS has remarkably better particle size resolution capability. We also demonstrated the size measurement advantage of spICP-MS over DLS for commercial CeO2 nanoparticles that are commonly used in the semiconductor industry, where quality control of the nanoparticle size distribution is critical for the wafer polishing process. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering has been employed to characterize the adsorption of an oligopeptide containing histidine residues on colloidal nanoparticles of metals as Ag and Cu obtained by laser ablation. The title molecule consists of two histidine and glycine residues alternating along the chain and terminating with an acetyl on one side and an amide group on the other. Histidine residues are found to act as docking sites of the molecule to the surface of the metal nanoparticles. Semiempirical parameterized model number 3 (PM3) calculations performed on molecule/metal model complexes suggest possible different adsorption geometries depending on the metallic substrate. This investigation could provide useful information to address the interaction of protein systems with metal ions, which is often related to fundamental biological process in living systems and can play an important role in different neuropathological diseases. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The application of combined diagnosis and therapy through nanotechnology applications is attracting increasing attention worldwide. Polymeric self-assembled nanoparticles (NPs) have been studied for this purpose. Micelles and vesicles with or without a magnetic core can efficiently carry diagnostic and/or therapeutic agents to a desired target. The biological behavior of these NPs has been evaluated in this study, after radiolabeling with 99mTc. In vitro stability, in media that mimic the environment of the living body, was better for vesicles than for micelles at 1 h and decreased for both as time passed. After administration to healthy animals, all NPs presented major uptake at liver and spleen as expected. Biodistribution and imaging studies confirmed the higher uptake in these organs for the hybrid NPs and at higher extent for the ones with larger size, indicating that the magnetic load and size play an important role on in vivo distribution. [ABSTRACT FROM AUTHOR]

Objective: In current exploration, systematic attempts have been made to improve the entrapment efficiency of a model hydrophilic drug substance, i.e. acyclovir, in poly (d, l) lactide (PLA) nanoparticles (NPs) using a modified nanoprecipitation technique. Methods: Formulation parameters such as drug to polymer ratio, antisolvent selection, electrolyte (NaCl) addition, pH alteration and temperature were screened to improve the entrapment efficiency of acyclovir in PLA NPs. The temperature of the system (0-5 °C), phase volume ratio (1:2), stirring speed (2000 rpm), sonication time (5 min), etc. were kept constant during the preparation of NPs. Drug to polymer ratio and electrolyte addition emerged as critical formulation parameters affecting particle size as well as entrapment efficiency. Hence, in the present investigation a 32 full factorial design was used to investigate the combined influence of two factors, i.e. drug to polymer ratio ( X1) and the amount of electrolyte, i.e. NaCl ( X2) on particle size ( Y1) and entrapment efficiency ( Y2). The NPs were also evaluated for drug-excipient compatibility study by employing DSC and FT-IR analysis, whereas in vitro drug release studies were performed using dialysis bag technique in phosphate buffer pH 7.4. Results: Statistically significant models were evolved to predict entrapment efficiency and particle size. The effect of factors X1, X2 and was found to be statistically significant in nature. Response variables, i.e. entrapment efficiency and particle size, were simultaneously optimized using desirability function using Design Expert software. This process allowed the selection of most suitable level of factors to achieve desired level of particle size and entrapment efficiency. The results of multiple linear regression analysis revealed that for obtaining desirable particle size (less than 250 nm) and entrapment efficiency (more than 17%), the NPs should be prepared using 1:3 drug to polymer ratio and 0.04 M NaCl. Acyclovir was found to be compatible with PLA as indicated by DSC and FT-IR studies. The experimental values obtained from the optimized formulation highly agreed with the predicted values. The drug release from the optimized formulation exhibited biphasic pattern and the drug release kinetics was best explained by Weibull model. Conclusion: In conclusion, results of the present study demonstrated that PLA NPs with expected particle size and entrapment efficiency can be obtained by adopting the concept of quality by design. [ABSTRACT FROM AUTHOR]

Heavy metal fluorides like BiF3 as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water-dispersible ultrasmall BiF3 nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln3+) ions. Through suitable Ln3+ doping, BiF3 exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non-toxicity of both bismuth and PVP can be advantageous for the potential use of BiF3 nanoparticles in drug delivery and bioimaging. [ABSTRACT FROM AUTHOR]

In this paper, we describe the synthesis of CeO2 nanoparticles by nanocasting route on the mesoporous silica support. In the first step, mesoporous silica (SBA-15 structure) was prepared using a soft template and in the second step, this material was used for impregnation with CeO2 nanoparticles. The obtained nanocomposites were morphologically and structurally characterized by XRD diffraction, FT-IR, UV-Vis and PL spectra. [ABSTRACT FROM AUTHOR]

Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are α = 3.1 Å and c = 3.4786 Å and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal) which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM). The size is found to be 100 nm. Uniform bright rings are noticed in the TEMpicture suggesting that the nanocrystals have preferential instead of randomorientations. The selectedarea electron diffraction (SAED) pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR). The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II) is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, λ, is calculated using the EPR and optical absorption spectral results suggest some covalent bond betweenmetal and ligand. Near infrared (NIR) spectra are due to hydroxyl and water fundamentals. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS) has gained much importance in recent years as a powerful tool for reliable analytical characterisation of nanoparticles (NPs). The outstanding capabilities of different MS-based techniques including elemental and molecular detection and their coupling with different separation techniques and mechanisms are outlined herein. Examples of highly valuable elemental and molecular information for a more complete characterisation of NPs are given. Some selected applications illustrate the analytical potential of MS for NP sizing and quantitative assessment of the size distribution as well. [ABSTRACT FROM AUTHOR]

Nano- and microparticles have optical, structural, and chemical properties that differ from both their building blocks and the bulk materials themselves. These different physical and chemical properties are induced by the high surface-to-volume ratio. As a logical consequence, to understand the properties of nano- and microparticles, it is of fundamental importance to characterize the particle surfaces and their interactions with the surrounding medium. Recent developments of nonlinear light scattering techniques have resulted in a deeper insight of the underlying light-matter interactions. They have shed new light on the molecular mechanism of surface kinetics in solution, properties of interfacial water in contact with hydrophilic and hydrophobic particles and droplets, molecular orientation distribution of molecules at particle surfaces in solution, interfacial structure of surfactants at droplet interfaces, acid-base chemistry on particles in solution, and vesicle structure and transport properties. [ABSTRACT FROM AUTHOR]

The article offers information on the development of different aspects of core/shell nanoparticles including their synthesis, characterization techniques, and applications. It offers brief information on the classes and the different shapes of nanoparticles, as well as their influences. It mentions that in their synthesis, maintaining their uniform coating and controlling the thickness of their shell are the most important steps.

Manganese ferrite (MnFe 2 O 4 ) nanoparticles (NPs) were synthesized by a coprecipitation method, in which an organic alkali, 1-amino-2-propanol (MIPA), was used. The effects of hexadecyl (trimethyl) azanium bromide (CTAB) on magnetic properties of the as-synthesized MnFe 2 O 4 NPs were studied. The saturation magnetization ( M s ) is increasing with the concentration of CTAB to 0.5 mM, and it decreases when the concentration of CTAB further increased to 1.0 mM, where the maximum Ms of the sample is 54.5 emu/g. The effects of CTAB on the crystal size and particle size for these samples were studied, which were used to explain the M s differences of these samples. At the same time, the crystallization and the adsorption of CTAB on the samples may also affect the magnetic property of the sample. [ABSTRACT FROM AUTHOR]

Nanoparticles exhibiting zero backscattering but a large scattering cross section in the forward direction should play a key role as light diffracting elements in photonic devices like solar cells. Using Mie theory we address lossless dielectric spheres that were recently reported to possess a magnetodielectric response to the illuminating wave, and analyze their scattering cross section together with their zero-backwards scattering conditions. We show that there is an optimum particle refractive index (m = 2.47), which yields maximum forward scattering without backwards scattering of light. [ABSTRACT FROM AUTHOR]

Barium borate (β-BaB2O4) nanoparticles were prepared by a hydrothermal technique using barium chloride and boric acid as starting materials. Powder x-ray diffraction confirms the pure single phase formation of β-BaB2O4. Fourier transform infrared spectroscopy spectra shows the presence of BO3 units which extend themselves to form (B3O6)3− anionic groups in β-BaB2O4. Scanning electron microscopy imaging shows the two-dimensional undulating particle surface with particle size in the range of 45–170 nm. β-BaB2O4 has strong absorption in the UV region and it possesses a wide optical transmittance window (201 to 1100 nm). The optical band gap of the β-BaB2O4 nanoparticle is estimated to be 5.9 eV. In the photoluminescence spectra the presence of self trapped excitonic state (347 nm) was identified. The third order optical nonlinearity of the sample excited in two different pumping regimes, short pulse excitation (532 nm, 5 ns) and continuous wave laser (532 nm, 50 mW) was studied. The material shows limiting behavior due to two photon absorption in the pulsed laser regime and self defocusing in the continuous wave regime. [ABSTRACT FROM AUTHOR]