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new type of paper with superhydrophobic surface was prepared by addition of modified nano-TiO to cellulose pulp. Nano-TiO powder was first dispersed with a high-speed homogenizer, followed by surface modification with the coupling agent, 3-(trimethoxysilyl) propyl methacrylate (MPS). The superhydrophobic and opaque paper was obtained by adding the modified nano-TiO to plant fiber to change its characteristics from hydrophilic to hydrophobic. The effects of the initial content of the coupling agent MPS used, on the weight percentage of MPS attached on the surface of nano-TiO were studied. The obtained paper was characterized by contact angle measurements and SEM. The results showed that the water contact angles for the modified paper ranged from 126.5 to 154.2°, and the sliding angle was <3°. Moreover, many well-dispersed nano-TiO protuberances were observed on the surface of the paper, which further confirmed that the obtained paper was superhydrophobic on account of its nanostructure. Comparative optical studies performed on the paper handsheets revealed a much higher opacity for the sample with the MPS-modified-TiO nanoparticles. [ABSTRACT FROM AUTHOR]

Cellulose insulation paper as a part of oil-paper insulation systems plays an important role in the reliability of converter transformers. The reliability of converter transformers equipped with traditional cellulose paper is adversely affected by space charge under DC voltage. The addition of nanoparticles into other dielectrics has been demonstrated to improve electrical performance. However, studies on the space charge behavior of cellulose paper reinforced with nanoparticles are rarely reported. This paper presents the results of a study aimed at elucidating the effect of nano-aluminum nitride (AlN) concentration on the space charge behavior of cellulose paper. Samples with various nano-AlN concentrations were fabricated and pretreated first. The micro-morphologies of prepared cellulose papers were observed using a field-emission scanning electron microscope. The space charge distribution was measured using a pulsed electroacoustic instrument. The results show the dependence of the charge injection as well as charge dissipation on the concentration of nano-AlN. The isothermal decay current method is used to obtain trap information. Based on the density and distribution of traps, the underlying mechanism of the effect of various concentrations on the space charge behavior is theoretically explained. [ABSTRACT FROM AUTHOR]

The carbothermal reduction of SiO2 gel containing filter paper (as carbon precursors) in argon was used to prepare SiC nanowires and nanoparticles. The resulting SiC ceramic, as well as the conversion mechanism of carbon/silica composites to SiC nanowires and nanoparticles, have been investigated by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG) techniques. XRD and IR studies show that the materials, obtained from reaction at 1550 °C for 1 h in static argon atmosphere, are β-SiC. SEM and TEM reveal that SiC nanowires is single crystal wires with diameters ranging from 50–200 nm and their lengths over several tens of microns. According to thermodynamic analysis, SiC nanowires and SiC nanoparticles in the resulting SiC ceramic are formed by gas-gas reaction of SiO (g) and CO (g). [ABSTRACT FROM AUTHOR]

Understanding the mechanisms behind sintering Cu-Ag core–shell nanoparticles can help us optimize the sintering process parameters and design the core–shell structure to achieve the desired sintering structure. In this paper, we employed molecular dynamics simulations to investigate the sintering behaviors and mechanisms of CS NPs, taking into account the effects of shell thickness, particle size, and temperature. Our results revealed that dislocation loops in Cu-Ag CS NPs played a crucial role in sintering by emitting dislocations that facilitated crystal evolution, thereby reducing the number of amorphous structures. The state of dislocation loops could be controlled by shell thickness and NP size. As the shell thickness decreased to 0.5 nm, the structure of the dislocation loops could not be generated due to the extremely chaotic and thin Ag atoms. Furthermore, for NPs of the same size, the CS NP with a 0.5-nm shell thickness was the most active. Despite the neck not consisting of a Cu core, the Cu core, particularly its interface, could still participate in the sintering process. At 900 K, limited interface diffusion could be activated. [ABSTRACT FROM AUTHOR]

Photodynamic therapy as an antibiotic-free method could effectively solve the bacterial infection problem and avoid the emergence of multidrug-resistant bacteria. In this paper, Ti3C2@gold nanorods (GNRs)/PDA nanoparticles with synergistic photodynamic antibacterial properties were obtained by coating PDA on the surface of in situ growth Ti3C2@GNRs. GNRs growing on the surface of Ti3C2 MXene nanosheets effectively prevented the aggregation of Ti3C2 nanosheets, which ensured the distinct photodynamic antibacterial performance of Ti3C2. In addition, the introduction of SH-PEG-CH3 to Ti3C2@GNRs nanosheets endowed Ti3C2@GNRs/PDA nanoparticles with good biocompatibility. Furthermore, Ti3C2@GNRs/PDA nanoparticles possessed synergistically enhanced photodynamic properties, caused by the remarkable photodynamic properties of Ti3C2 MXene and PDA. In addition, with the increase in PDA content, Ti3C2@GNRs/PDA nanoparticles could produce more 1O2 under 660 nm laser irradiation and the minimum inhibitory concentrations of Ti3C2@GNRs/PDA50 nanoparticles against E. coli and S. aureus decreased to about 0.07 mg/mL. Thus, this work utilizes the 1O2-generating performance of Ti3C2 MXene and PDA to fabricate Ti3C2@GNRs/PDA nanoparticles with synergistically enhanced photodynamic antibacterial activities, which is expected to be applied in antibiotic-free antibacterial field. [ABSTRACT FROM AUTHOR]

In this paper, graphite nanoplatelets (GNPs)-based polymer nanocomposites were reviewed. This review mainly discusses various synthesis techniques for making graphite nanoplatelets (GNPs) including dispersion of GNPs in polymers, functionalization and producing GNPs polymer nanocomposites. In addition, their critical morphology and rheological, mechanical, electrical, and thermal conductivity as well as gas barrier properties were explained. It was found that when GNPs were properly incorporated into the polymer matrix, they can enhance the properties of the host polymer at extreme conditions. Moreover, surface modification of GNPs by covalent and non-covalent functionalization has been explored as a new platform for realizing structure–property interactions of polymer nanocomposites. Proposed predictive modeling and analysis methods on the mechanical, electrical, and thermal conductivities and gas barrier properties of GNPs/polymer nanocomposites were also disclosed considering, in particular, GNPs geometry and orientation in polymers. It was concluded that GNPs added to thermoset and thermoplastic polymer nanocomposites exhibit conceivable developments in advanced engineering uses, including electronics, ultra-sensitive sensors, membranes, energy storage, wearable technology, aerospace and biomedical. [ABSTRACT FROM AUTHOR]

Through silicon via (TSV) is a kind of three-dimensional (3D) packaging technology with great development potential, which can realize short distance electrical interconnection. Currently, there were few related studies on filling or thermal reliability of SAC305-TSV. Because of its thermal expansion coefficient and other physical property parameters do not match with other materials involved in TSV and the crystal structure characteristics of Sn, SAC305-TSV has service reliability problems under the action of thermal load. In this paper, by adding different contents of SiC nanoparticles to SAC305, the performance of SAC305 was improved, and the composite solder with better comprehensive performance was obtained. Besides, the thermal reliability of TSV filled with composite solder was analyzed by thermal shock and aging test with SEM and EBSD. [ABSTRACT FROM AUTHOR]

The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient. [ABSTRACT FROM AUTHOR]

Oil spills cause serious environmental pollution and serious waste of resources, hydrophobic porous absorbent has been deemed as a simple, low-cost, efficient and environment-friendly in oil–water separation. In this paper, a facile emulsion template method was developed to fabricate an interconnected porous poly(DVB-MMA) sponge. A novel co-Pickering stabilization system of Span 80 and NiFe2O4 nanoparticles was applied to fabricate ultra-concentrated internal phase W/O emulsions. After further polymerization, the resulting sponge showed excellent adsorption selectivity due to superhydrophobicity and superlipophilicity. Also, the characterization results exhibited that the composite had superior thermal stability, low density, high porosity and flexible three-dimensional porous structure. Besides, waste PS plastic was introduced to enhance the structural integrity of composite, and the addition of NiFe2O4 provided the material with magnetic operability. High oil adsorption capacity (up to 44.3–101.0 g/g), high oil retention, fast adsorption rate and superior recyclability allowed the material to be used in the fields of oil–water separation and oil pollution treatment. [ABSTRACT FROM AUTHOR]

Pore structure, the most important structural feature of reactive powder concrete (RPC) with nanofillers, is closely related to the dispersion quality, content level and internal structure of nanofillers. In order to characterize the pore structure of RPC and comprehensively understand the effect of nanofillers on the microscopic behavior of concrete, this paper studies the pore structure of RPC containing different types (including zero-dimensional nanoparticles, one-dimensional nanotubes and two-dimensional nanosheets) and content (0.25–3%) of nanofillers by using low-field nuclear magnetic resonance. The experimental results show that incorporation of all types of nanofillers reduces the porosity of RPC and causes shrinkage of gel pores and fine capillary pores. Among different types of nanofillers, one-dimensional nanotubes are most beneficial to reduce porosity, and zero-dimensional nanoparticles have a more pronounced effect on reducing pore size. The effect of nanofillers on the pore structure of RPC is mainly attributed to the conversion of pore water inside C–S–H gel, inducing reorganization of gel structure. Specifically, nanoparticles cause the gel layer surrounding the pore water to shrink or even partially collapse, while nanotubes and nanosheets fill the collapsed gel layers with pore water, in turn, producing a slight swell between gel layers. It is the slight changes in the microstructure of C–S–H gel that cause shrinkage and deformation of concrete materials at the macroscopic scale, which, in turn, greatly affects the overall performances of RPC with nanofillers. [ABSTRACT FROM AUTHOR]

In this paper, urea group functionalized periodic mesoporous organosilica was utilized as matrix to introduce cobalt precursor into framework. After pyrolysis in nitrogen atmosphere, urea group was decomposed into carbon species and simultaneously the cobalt precursor was reduced to metallic cobalt nanoparticles. The metallic cobalt nanoparticles can be stabilized by coordinating to carbonyl oxygen atoms in carbon species. The supported metallic cobalt exhibited excellent catalytic performance towards 4-nitrophenol hydrogenation reaction. The largest turnover frequency number can reach up to 164.8 h−1, and the reaction rate constant can be as high as 0.77 min−1. The influence of pyrolysis temperature on catalytic performance was also investigated. Compared with the results obtained by samples prepared with wet impregnation method or different pyrolysis rate, it can be concluded that the coordination to carbonyl oxygen atom in carbon species plays a crucial role in improving electron transfer between metallic cobalt and carbon species during catalytic procedure. Metallic cobalt nanoparticles with high dispersion were introduced into urea group functionalized mesoporous silica matrix via pyrolysis in nitrogen atmosphere. The coordination to carbonyl oxygen atom enhances the catalytic performance in 4-nitrophenol hydrogenation. [ABSTRACT FROM AUTHOR]

The surface thermodynamic properties play an important role in researching into the thermodynamics of nanoparticles involved in various chemical and physical processes. In this paper, the relations between surface thermodynamics properties, respectively, and particle size of nanoparticles were deduced. A new method of determining the surface thermodynamic properties of nano-copper by equilibrium constant was proposed. On the basis of the equilibrium constants of nano-copper with different particle sizes dissolved in sulfuric acid at different temperatures, the effect of particle size on the surface thermodynamic properties was investigated and the variation of surface tension with temperature was obtained. The influence regularities of size on the surface thermodynamic properties agree with the theoretical analysis. With the decrease in particle size, the molar surface Gibbs energy, the molar surface enthalpy and the molar surface entropy increase, and when the diameter exceeds 20 nm, the surface thermodynamic properties exhibit linear correlation with the reciprocal of diameter, respectively. The surface tension decreases with temperature increasing, and a linear relation between them is observed. This paper provides us a simple and reliable method to obtain the surface thermodynamic properties of nanoparticles for better understanding their thermodynamic behaviors in the chemical reaction, adsorption, melting, etc. [ABSTRACT FROM AUTHOR]

This paper firstly studied an obvious magnetic transformation from paramagnetism to superparamagnetism in hydrogenated ZnFe2O4 nanoparticles. The zinc ferrite nanoparticles were successfully prepared by a simple solid-state reaction followed by a ball milling method. Moderate thermal treatments under hydrogen atmosphere were carried out, and a phenomenon was observed that the magnetic behavior of zinc ferrite nanoparticles transformed from paramagnetism to superparamagnetism. Various characterizations were carried out to confirm the creation of the hydrogen doping induced defects under post-treatments, which may be crucial for the magnetic transformation. By studying the effect of the defects caused by hydrogenation on the magnetization, we found that the oxygen vacancies could alter the magnetic ordering of materials and therefore modulate the magnetic behaviors. In addition, the saturation magnetization decreased after reheating the hydrogenated Zn-ferrite samples in the air, which indicated that the oxygen vacancies and Fe2+ ions directly modulated the magnetization of the Zn-ferrite materials. Notably, the residual saturation magnetization was still higher than raw Zn-ferrite, indicating that the changes of cation distribution could also modulate the magnetization and certain changes were irreversible. [ABSTRACT FROM AUTHOR]

Combining plasmonic noble metals with semiconductor materials has been considered to be an effective way to improve catalyst performance. In the present paper, Au nanoparticles (NPs) were decorated onto CVD-grown β-Ga2O3 nanowires (NWs) through a chemical reduction method. Different quantity of HAuCl4 solution was used to control the size and density of Au NPs. The photocatalytic activity of the Au-Ga2O3 NWs is evaluated by degrading rhodamine B (Rh B) under UV and visible light irradiation. It is found that the size and density of the Au NPs had a great influence on the photocatalytic efficiency of β-Ga2O3 NWs. And Ga2O3 NWs with Au NPs of ~ 5.7 nm size and ~ 420/μm2 density shows the best catalytic efficiency. Moreover, Au NPs attachment on the Ga2O3 could extend its photocatalytic activity towards the visible light irradiation, which is significant to efficient utilization more solar light. A jointly effect of both the interfacial Schottky potential field between Au NPs and β-Ga2O3 NWs and local surface plasma resonance excitation is proposed to contribute the enhancement effects. [ABSTRACT FROM AUTHOR]

With the microelectronics technology going toward its physical limits and the emergence of three-dimensional chip stack architectures, now more than ever there are both needs and opportunities for novel materials to help address some of these pressing thermal management challenges. In this paper, a high-thermal-conductivity insulative SiO2-coated nano-Cu particle is prepared for new-type underfill materials of high-performance microelectronics packaging. It was found that nano-Cu can be successfully coated with SiO2 by using the surface modification between cetyltrimethyl ammonium bromide and silane coupling agent although nano-Cu particles have silicon-disordered property during the coating process of tetraethyl orthosilicate hydrolysis. Moreover, the thermal conductivity of epoxy mixed with nano-Cu@SiO2 as the packaging underfill is dramatically increased from 0.15 W/m K of the pure-EP and 0.60 W/m K of the EP/SiO2 to 2.9 W/m K due to electronic heat transfer, heat network and fast heat transfer center. It effectively releases the heat generated by the IC device, and the service life of the device is significantly improved from 63 min of pure-EP and 350 min of the EP/nano-SiO2 to 1039 min. The new material creates a challenging environment for keeping modern electronic devices cool, a critical factor in determining their speed, efficiency and reliability. [ABSTRACT FROM AUTHOR]

Some efforts have been made to strengthen the environment friendly natural fiber-reinforced polylactide composite (NFPC), but common approaches impair its ductility. This paper successfully synthesized the rigid-soft core-shell nanoparticles which are feasible to simultaneously improve the strength and toughness of NFPC. The core-shell structure was molecularly designed to act the nano-silica and poly (butyl acrylate) rubber as rigid inner core and soft outer shell, respectively. Furthermore, the devised active functional groups at the end of core-shell filler also interact with polylactide (PLA) matrix to form strong interface. The effect of core-shell nanoparticle on crystalline, thermal and mechanical properties of NFPC was investigated. The results showed that the core-shell nanofiller can facilitate to form the more complete crystalline grain of PLA matrix and the thermal stability improvement of NFPC. More attractively, the addition of the rigid-soft core-shell nanoparticle enhanced the strength and stiffness of NFPC without sacrificing its elongation at break. Finally, the toughness improvement mechanisms and synergistic effect of core-shell nanoparticles were illustrated via field emission scanning electron microscope. It indicates that the micro-cracks, shear band and fibration of the matrix induced by the core-shell filler are the main causes of toughness improvement. [ABSTRACT FROM AUTHOR]

Effective thermal conductivity models for nanosheet-based composites are less common than those for composites containing spherical nanoparticle. A novel theoretical model for effective thermal conductivity is proposed aiming to the sheet-like nanoparticle polymer composites in this paper, and comparative analysis is made with other relevant models as well as experimental data. The effective thermal conductivity of the anisotropic nanoparticle is obtained by analysing the differential equations of a sheet-like nanoparticle with an interphase layer in both in-plane and through-plane directions in a cylindrical coordinate system. Then the present model is established based on the Nan’s model and the solutions of these differential equations. The present model which contains the effects of detailed geometry and anisotropy of nanosheet as well as interphase layer are analysed and validated with other models and experimental data. The results of present model are in good agreement with some available experimental results. [ABSTRACT FROM AUTHOR]

The new composite MoS2/CeO2-Co3O4 showed high efficiency of hydrogen evolution under visible light irradiation, and the synthesis and properties of photocatalyst were also introduced in this paper. The hydrogen evolution of 1%MoS2/CeO2-Co3O4 catalyst reached 221 μmol in 3 h, and the catalyst still exhibited high activity after 12 h under visible light irradiation of 10%TEOA solution, which indicates that the photocatalyst had excellent photocatalytic activity and light stability. The analysis of XRD, XPS, SEM and TEM showed that MoS2/CeO2-Co3O4 was successfully synthesized. The analysis of BET showed the specific surface area of photocatalyst composite increased due to the addition of CeO2 and MoS2, which was good for EY adsorption, accelerated the electron transfer rate and improved the production of hydrogen. The PL and electrochemical analysis results showed that CeO2-Co3O4 loaded on the surface of MoS2 nanoparticles can significantly promote electron transfer, restrain the recombination of electron and hole and improve the rate of hydrogen production. Therefore, the oxide of the rare-earth element Ce and Co3O4 might be good for the design of a new photocatalyst. [ABSTRACT FROM AUTHOR]

Reducing the side effects and improving the drug utilization are important work in anti-cancer drug delivery. In this paper, a novel dual-pH-sensitive drug delivery system was reported. Mesoporous silica nanoparticle (MSN) was applied to load anti-cancer drug doxorubicin hydrochloride (DOX) and was covered by mono-6-deoxy-6-EDA-β-cyclodextrine (β-CD-NH2) to block the pores through pH-sensitive boronate ester bond. And the carriers were then coated with methoxy poly(ethylene glycol) (mPEG) through another pH-sensitive benzoic imine bond. mPEG leaving studies, in vitro cellular uptake studies and the flow cytometry analysis, proved that carriers was “stealthy” at pH 7.4, but could be “activated” for cytophagy by cancer cells in weakly acidic tumor tissues (pH 6.5) due to the departure of mPEG. β-CD-NH2 leaving studies, the in vitro drug release studies and the in vitro cytotoxicity studies proved that boronate ester bond linking MSN and β-CD-NH2 was stable at both pH 7.4 and 6.5, but could be hydrolyzed intracellular to release DOX for cellular apoptosis due to the lower pH (5.0). In summary, the novel dual-pH-sensitive drug delivery system fabricated with a dynamic protection strategy should have great application potential in anti-cancer drug delivery fields. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites are promising materials for dielectric waveguides in high-data-rate communications, where extremely low loss is required. In this paper, we study the effect of titania (TiO2) nanoparticle size (30-300 nm) and concentration on the effective permittivity (εeff) and dielectric loss (tan δ) of polypropylene (PP) nanocomposites in two different frequency ranges: 100 Hz-300 kHz and 140 GHz-220 GHz. To aid the dispersion of TiO2 in the PP matrix, polypropylene-graft-maleic anhydride (PP-g-MA) is added. Using this approach, an εeff of 6.84 with tan δ of 0.0049 at 220 GHz is achieved in a 21.5 vol% 100 nm TiO2/PP nanocomposite. We find that εeff is insensitive to nanoparticle size in both frequency ranges while tan δ appears to depend on the filler size at the low frequency range. By using complex permittivity in Lichtenecker’s model, we are able to separate the loss contribution of the polymer matrix from that of the TiO2 nanoparticles. Our results provide insight into the choice of nanoparticle size and the effects of compatibilizer on millimeter-wave dielectric properties. [ABSTRACT FROM AUTHOR]

In the present paper, we report a detailed study on the sodium (Na) doping-induced modifications in the copper oxide (CuO) nanostructure and its properties. A facile and sustainable sol-gel synthesis approach was employed for the preparation of high-quality pristine CuO- and Na-doped CuO nanostructures(1.0, 3.0, 5.0 and 7.0 mol% doping levels, CuO/Na) with controlled shape and composition. Due to the remarkable difference in the ionic radii of Cu2+ (0.73 Å) and Na+ (1.02 Å), Na+ substitution in place of Cu2+ generates strain/distortions in CuO lattice. The XRD analysis reveal the structural alteration from monoclinic to cubic symmetry with increase in doping level and also reveal the phase purity up to 3% doping level, and beyond this (i.e., for 5 and 7% doping level) small amount of impurity phase corresponding to Na2O was observed. The FTIR results further confirmed the presence of the Na-Cu-O stretching vibrations at higher Na-doped samples. Morphology of the samples indicates that the Na-doped CuO nanostructures exhibit less agglomeration compared to pristine CuO nanoparticles. The presence of Na in CuO lattice were found to greatly enhances optical and electrical properties owing to the formation of defects like copper vacancies and oxygen vacancies at the grain boundaries of the nanoparticles with increased doping of Na. [ABSTRACT FROM AUTHOR]

In this work, gold nanorods (AuNRs)/mesoporous silica (SiO2) nanoparticles capped with thermal-responsive polymer were fabricated to couple the photothermal property of AuNRs and the thermal-/pH-responsive properties of polymer in a single nanovehicle. Aliphatic poly(urethane-amine) (PUA) was employed as the smart polymer to cap the mesopores of AuNRs/SiO2 nanoparticles via in situ polymerization in supercritical CO2. Thermal-/pHresponsive PUA acted as the on–off switch to control the DOX release due to the stretch and shrinkage of the PUA polymer chains at different temperatures, whereas a remote near-infrared (NIR) light was used to activate the phase change and subsequent drug release. The in vitro drug release studies indicated that Au/SiO2/PUA nanoparticles exhibited distinguished pH-, thermal-, and NIR-dependent release properties. A short time exposure to NIR irradiation could distinctly increase the local temperature of nanoparticles, and the thermal-responsive polymeric cap enabled the DOX release in a significant reversible way by simply adjusting the NIR laser intensity. The present paper provides an ideal way to fabricate NIR-responsive drug carriers by combining stimuli-responsive polymer with inorganic matrix, which is highly attractive for remote controllable drug delivery. [ABSTRACT FROM AUTHOR]

This paper introduces a laser-interference-controlled electrochemical deposition method for direct fabrication of periodically micropatterned magnetite (FeO) nanoparticles (NPs). In this work, FeO NPs were controllably synthesized on the areas where the photoconductive electrode was exposed to the periodically patterned interferometric laser irradiation during the electrodeposition. Thus, the micropattern of FeO NPs was controlled by interferometric laser pattern, and the crystallization of the particles was controlled by laser interference intensity and electrochemical deposition conditions. The bottom-up electrochemical approach was combined with a top-down laser interference methodology. This maskless method allows for in situ fabrication of periodically patterned magnetite NPs on the microscale by electrodeposition under room temperature and atmospheric pressure conditions. In the experiment, FeO NPs with the mean grain size below 100 nm in the pattern of 5-μm line array were achieved within the deposition time of 100 s. The experiment results have shown that the proposed method is a one-step approach in fabricating large areas of periodically micropatterned magnetite NPs. [ABSTRACT FROM AUTHOR]

The present paper demonstrates the effect of Zn ion doping on structural, electrical and optical properties of monoclinic CuO nanoparticles prepared via microwave combustion method. The crystal structure, optical and electrical properties of synthesized CuO and Zn-doped CuO samples were characterized by X-ray diffraction study, field emission scanning electron microscopy, energy-dispersive X-ray diffraction study, UV-Visible spectroscopy, transmission electron microscopy and photoconductivity technique. The XRD values show that the crystalline size of Zn-doped CuO nanoparticles was varied with Zn concentration and also it depends on the micro-strain and dislocation density of CuO lattice. FE-SEM and TEM images indicated that the synthesized samples are of the cube and rod-like structures in nature. The band gap of CuO nanoparticles has been calculated using Tauc's plot and the result showed that the incorporation of Zn has decreased the bandgap of CuO. The I-V characterization study was performed to determine the electrical property of CuO and Zn-doped CuO films. From the results, it is observed that the photocurrent of CuO and Zn-doped CuO films is found to be greater in UV-light as compared to dark. [ABSTRACT FROM AUTHOR]

In preparation and application of nanomaterials, the dissolution of nanoparticles is usually involved. However, it remains unclear about size dependent the dissolution kinetic parameters of nanoparticles. In this paper, kinetic model for the dissolution of nanoparticles is proposed, and the relations between dissolution kinetic parameters (rate constant, order, apparent activation energy and pre-exponential factor), respectively, and particle sizes were theoretically deduced by applying the transition state theory to the dissolution process, and then the influence regularity and mechanism of particle size on the kinetic parameters were discussed. Experimentally, the dissolution kinetic parameters of nano-CaCO with different particle sizes were determined by conductivity meter, and the quantitative influences of particle size on the dissolution kinetics were obtained. The experimental results are consistent with the theoretical relations. The results show that there are significant effects of the particle sizes of CaCO nanoparticles on dissolution kinetic parameters; with the particle diameter decreasing, the apparent activation energy and the pre-exponential factor correspondingly decrease, while the rate constant and the dissolution order increase sharply. When the diameter of nanoparticle exceeds 20 nm, the logarithm of the dissolution rate constant, the apparent activation energy, and the logarithm of the pre-exponential factor are all linearly related with the reciprocal of particle diameter. Furthermore, the apparent activation, the dissolution order, the pre-exponential factor, and the dissolution rate constant are influenced by the partial molar surface enthalpy, the partial molar surface area, the partial molar surface entropy, and the partial molar surface Gibbs energy, respectively. [ABSTRACT FROM AUTHOR]

High-quality Au@CdS core-shell nanoparticles (CSNs) have been synthesized to improve photo-conversion efficiency in photocatalysis. They demonstrate higher photocatalytic activity in the experiment of photocatalytic degradation of rhodamine 6G (R6G) solution than that of CdS counterparts. Au@CdS CSNs can broaden the absorption range in visible region compared to CdS counterparts. The heterojunction interface between Au and CdS facilitates the separation of photo-generated electron-hole pairs, and transfers electrons from CdS region to Au core. The two advantages are crucial to improve the photocatalytic activity of Au@CdS CSNs. Charge transfer mechanism between metal and semiconductor is efficient that can be used to guide the design of photocatalysts, photovoltaics, and other optoelectronic devices to effectively utilize the solar power. In this paper, we research the photocatalytic process by surface-enhanced Raman scattering (SERS). The combination of photocatalysis and SERS not only can show the change in concentration of R6G solution, but also can provide the information of the change of R6G molecular structure in photocatalytic process. [ABSTRACT FROM AUTHOR]

An elementary, probabilistic model for fiber failure, developed by Coleman in the fifties of the last century, predicts a Weibull distributed time-to-failure for fibers subject to a constant load. This has been experimentally confirmed, not only for fibers but for load-bearing products in general. In this paper, we analyze residual strength, i.e., the strength after having survived a given load program. We demonstrate that the Weibull modulus, describing variability of time-to-failure, affects residual strength. It determines (a) how fast residual strength of fibers decays during their service life, (b) the residual strength variability, and (c) the fraction of surviving fibers during service life. Experiments show that residual strength of Twaron fiber (p-aramid fiber), exceeding predictions of Coleman's model, remains unrelentingly high (close to virgin strength) during service life. [ABSTRACT FROM AUTHOR]

In this paper, we present a convenient and universal strategy to sequentially assemble titania (TiO) nanorods and polyaniline (PANI) nanoparticles on the Si wafers through hydrothermal synthesis and chemical oxidation. On the one hand, the composite coatings (PANI/TiO/Si) with hierarchical structures reduced the reflectivity to less than 5 % at the wavelengths from 200 to 2500 nm, namely increasing the absorption efficiency of incident light. On the other hand, the double P-N heterojunctions that the composite coatings developed could suppress the recombination of photogenerated carriers, namely enhancing utilization efficiency of absorbed light. The photocurrent density of PANI/TiO/Si was above two times higher than that of TiO/Si at 1.5 V of positive potentials. The application of such coatings in the photocatalysis area, which are fabricated with this method, is thus straightforward. [ABSTRACT FROM AUTHOR]

This is the first in a series of papers, focused on the development of a biodegradable, controlled, and potentially targeted drug delivery system. In this paper, we describe the production of highly porous biodegradable fibrous structures suitable for biomedical applications and as a matrix for drug delivery. Two structures are described below. The first structure is composed of electrospun poly(lactic acid) (PLA) fibers and is unique due to (1) the uniformity if its constitute fibers' diameter, (2) consistent surface pore dimensions of each fiber, (3) the use of only a single solvent, (4) interior nano-size porosity throughout each individual fiber, and (5) the independency of surface pore dimensions on fiber diameter. The produced matrix will be further impregnated with cargo loaded nanoparticles- Red clover necrotic mosaic virus (RCNMV)-to achieve a controlled drug delivery system (described in Part III) for cancer treatments. Such a structure can also be used as tissue engineering scaffolds and filter media. The second electrospun structure has enhanced hydrophilicity compared to PLA matrix and is formed by blending poly(lactic acid)/poly(ethylene oxide) (PEO) polymers. The incorporation of PEO in the matrix introduces preferable sites for aqueous compounds to be attached to while retaining the overall structural integrity and porous morphology. It is hypothesized that the existence of alternative hydrophilic and hydrophobic segments in the structure may reduce post-implantation complications such as platelet adhesion. [ABSTRACT FROM AUTHOR]

Theoretical analysis of Poly-( l)-Lactic Acid (PLLA) nanofibers is a necessary step towards designing novel biomedical applications. This paper aims to analyze the mechanical properties of PLLA nanofibers so that optimal scaffolds in tissue engineering applications can be developed. We carry out analysis of PLLA nanofibers to estimate the mechanical properties from basic building blocks to the nanofibrous structures. A single PLLA nanofiber is made up of Shish–Kebab like fibrils intertwined together and can contain both amorphous and crystalline phases. The elastic modulus of the Lactic acid monomeric formation in the crystalline phase is derived using second-derivative of the strain energy using molecular dynamics simulation. The mechanical property of the Shish–Kebab fibril is derived by homogenization. The fiber modulus is then obtained using the Northolt and van der Hout’s continuous chain theory. One of the significant contributions in this paper is the use of modified continuous chain theory, where a combined multiscale approach is used in the estimation of the mechanical properties of PLLA nanofibers. The theoretical results correlate well with reported experimental data. [ABSTRACT FROM AUTHOR]

Several mechanochemical methods for synthesizing nanostructural materials have been introduced in this paper. The methods are three different routes; one is a direct synthesis method, the second is a combination method, which composes of grinding, heating and washing, and the third is a doping one. Dry grinding a mixture facilitates the solid-state reaction (MC reaction), to form a product of fine particles with nanostructure of grains and their boundaries in lattice configuration. The micro-structure of material depends mainly on grinding energy and the composition of starting mixture. Under the grinding energy enough for mechanochemical synthesis, the synthesized material tends to be aggregated, so that the specific surface area (SSA) is not large. In order to increase the SSA, the combination method is recommended. The doping method is another concept, enabling us to cause a partial MC reaction in the fine particles. The chemical form and structure of the material depend mainly on a mixing ratio of the starting samples. The authors have attempted to form different functional materials such as catalysts from various starting samples by using a planetary mill, and introduced some of them in the present paper. [ABSTRACT FROM AUTHOR]

Nano-sized precipitates in Al-Mg-Si alloys can effectively increase the mechanical property of these alloys. However, nanoscale dimensions and orientation variations greatly impede the understanding of crystal structures and phase relations of precipitates. In this paper, the structural stability, mechanical, and electronic properties of twelve Al-Mg-Si compounds in Al-Mg-Si alloys are examined systematically using first-principles calculations. The calculated results of MgSi and MgAlSi agree well with the previous experimental and theoretical results. The MgSi with $$ P\bar{1} $$ symmetry, MgAlSi with C2/ m symmetry, and MgAlSi with Pccn symmetry are identified as the more energetically and mechanically favorable phases suggested by our calculations. According to the predictions, MgSi and MgAlSi exhibit higher bulk moduli, 73.1 and 67.7 GPa, due to the tightly bounding Si-Si/Si-Al covalent networks. [ABSTRACT FROM AUTHOR]

Microfibrillated cellulose (MFC)-SiO nanopapers were prepared using a rapid spray deposition technique. Large area (~310 cm) composite nanopapers with thickness and SiO content varying from 16 to 92 µm and 0 to 33 %, respectively, were prepared in less than 30 min with nearly complete nanoparticle retention in the cellulose mat. In the presence of an excess of MFC, SiO nanoparticles formed large clusters embedded in a dense and continuous cellulose matrix which conferred to the composite an extremely low permeability to air, i.e., below 2 nm. For silica mass fraction above 20 %, SiO clusters induced a net increase in air permeability and ionic conductivity up to 12 nm and 1.5 mS cm for a SiO content of 33 %. Despite the addition of an inert phase, composite nanopapers displayed mechanical properties, viz. Young's modulus and internal cohesion higher than 2.2 GPa and 913 J m, outperforming those of most conventional papers. This study demonstrates that MFC-SiO nanopapers fabricated by spray deposition can be an alternative to PE/PP membranes as separators in Li-ion batteries and, in general, that spray deposition is a promising method for the rapid fabrication of large area composite nanopapers. [ABSTRACT FROM AUTHOR]

In this paper, nanosuspensions of three arsenic sulfide (AsS) compounds, commercial synthetic arsenic(II) sulfide, and natural realgar and pararealgar minerals were prepared. Nanosuspensions were obtained by ultrafine wet milling in a circulation mill. The zeta potential and particle size distribution were measured for stability estimation. Structural changes were studied using Raman and Fourier transform infrared spectroscopic methods and positron annihilation lifetime method. The morphology of the prepared nanoparticles was determined using scanning and transmission electron microscopy. The anticancer effects were tested using flow cytometry and western blotting analysis. The average particle size in the individual samples varied from 137 to 153 nm. The effects of milling were associated with the formation of arsenic sulfide crystalline nanoparticles and the fragmentation of the corresponding free-volume entities. Consequently, an increase in the arsenic dissolution was observed. The anti-cancer effects of the nanosuspensions were verified on the human cancer H460 cell line, in which case DNA damage and greater numbers of apoptotic cells were observed. [ABSTRACT FROM AUTHOR]

In this paper, the substitution of Mg by Cu on the synthesis and properties of (MgCu)AlOHCO, nHO LDHs has been studied. Samples have been synthesized by the coprecipitation method using varying pH method. Physicochemical characterization of the obtained samples was performed by a combination of techniques such as X-ray diffraction, SEM, BET-specific surface area, UV-Visible spectrometry, EPR spectrometry, and thermogravimetric analysis. For all the syntheses, whatever the Mg/Cu ratio, a single phase was obtained. For low copper contents (x < 2.6), the single phase is a rhombohedral LDH. For higher copper contents, a symmetry decrease was observed and the layered hydroxide compound is monoclinic, due to distorted Cu(OH) octahedra by Jahn-Teller effect. Additionally, thermal stability of the compounds decreases when Cu content increases. Samples with the monoclinic cell do not show any affinity for nitrates and an even higher affinity for carbonates compared to MgAl-LDH. For the samples with the LDH structure, the captured nitrate content increases as the copper content increases but remains limited. All the samples also lead to amorphous mixed oxide nanoparticles when heated at moderate temperature. [ABSTRACT FROM AUTHOR]

This paper describes a powerful and facile synthesis of CdSe hollow nanostructures via a sacrificial template method employing the Kirkendall diffusion effect for void formation and an anion exchange reaction for selenization. The CdSe hollow nanowires and nanoparticles were easily transformed from a sacrificial template of CdO nanowires that were formed by thermal Ostwald ripening. The distinctive structures of CdO sacrificial templates were developed through thermodynamically spontaneous process. The morphology of each CdSe nanostructure could be controlled by one of each CdO sacrificial template which was calcined at several different temperatures. Their microstructure was analyzed by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, and their optical properties were compared using light absorption. The suggested process for synthesis of hollow nanostructures could also be applied to the formation of other hollow chalcogenide compounds. [ABSTRACT FROM AUTHOR]

In this paper, the potential of the SrAlO: Eu,Dy fluorescent nanophosphor is explored to visualize the latent fingermarks. The nanophosphor has been synthesized using self-propagating high temperature synthesis and shows intense luminescence and strong long after glow properties. These nano particles have been characterized for their particle size, crystalline phase, and photoluminescent properties. The calculated PL CIE co-ordinates (0.138, 0.359) correspond to the blue-green shade. Different porous, non-porous, as well as slightly non-smooth surfaces are taken and successfully tested for latent fingerprints development with the prepared SrAlO: Eu,Dy fluorescent nanophosphor powder. Present nano powder is advantageous to use on luminescent or multicolored surfaces as it gives greater contrast and also eliminates the problem of background interferences with the friction ridges due to its strong long after glow property. The results are very good when latent fingerprints were developed on the currency notes with optical variable ink and highly fluorescent pattern areas. [ABSTRACT FROM AUTHOR]

In this paper, a new model based on the micromechanical and normalized stiffness degradation approaches is established. It has been assumed that during the fatigue condition, only material properties of composites (fiber and matrix) were degraded and nanofillers remain intact under different states of stress. A normalized stiffness degradation model was proposed for laminated fibrous composites reinforced with nanoparticles to derive a novel model to predict the stiffness reduction. The developed model is capable of predicting the fatigue life of nanoparticle-filled fibrous composites based on the experimental data of fibrous composites without nanofillers. The new fatigue model is verified by applying it to different experimental data provided by different researchers. The obtained results by the new fatigue model are in very good agreement with the experimental data of nano-silica glass/epoxy composites under constant cyclic stress amplitude fatigue and also for silica/epoxy nanocomposites in various states of stress with negligible error. [ABSTRACT FROM AUTHOR]

A nanosized carbonaceous material was derived from bacterial cellulose (BC). BC, which is produced by bacteria as nanosized material, possesses high degree of crystallinity of 90 %, was pyrolysed at 950 °C and physically activated with CO to produce a nanosized activated carbon material. The pyrolysis of BC yielded a carbonaceous material (carbon yield of between 2 and 20 %) with a relatively low D- to G-band ratio (between 2.2 and 2.8), indicating that the carbonaceous material possesses a graphitic structure. Two different BC materials were pyrolysed-a loose fibrous (freeze-dried) and dense paper form. It was observed that a carbon nanofibre-like material was produced by the pyrolysis of the loose fibrous form of BC. The electric double layer (EDL) capacitance and the area-normalised specific capacitance in KSO solution were as high as 42 F g and 1,617 F cm, respectively. The EDL capacitance was also compared to commercially available activated carbon (YP-50F). [ABSTRACT FROM AUTHOR]

In this paper, we report a new method for effective immobilization of Ag nanoparticles (AgNPs) decorated graphene oxide (AgNP/GO) composites onto thiolated single-stranded DNA decorated Au electrode (AuE) surface. The novel immobilization method is based on the coordination interactions and π-π stacking interactions between DNA bases and AgNP/GO composites. The morphologies of the AgNP/GO nanocomposites are characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is found that the AgNP/GO-decorated AuE exhibits remarkable catalytic performance for HO reduction. This HO sensor has a fast amperometric response time of less than 5 s. The linear range is estimated to be from 0.1 mM to 20 mM ( r = 0.998) and the detection limit is estimated to be 1.9 μM at a signal-to-noise ratio of 3, respectively. [ABSTRACT FROM AUTHOR]

Nanomaterials, defined as particles ranging from 1 to 100 nm diameter, have become widely utilized because of their unique physicochemical properties. Among those nanoparticles, titanium dioxide (TiO) is frequently used in the production of paints, paper, plastics, welding rod-coating material, cosmetics, etc. TiO is the most commonly used semiconductor photocatalyst. Among the different nanomaterials, it is the most studied. Activated by UV-A irradiation, its photocatalytic properties have been utilized in various applications. A wealth of information on TiO photocatalytic in activation of bacteria has been acquired over the last 20 years. Hence, in this review article we have described synthesis methods mainly sol-gel type method like sol-gel method, ultrasonic-assisted sol-gel method, microemulsion method, colloidal synthesis, and also other method are discussed like solvo-thermal method, thermal plasma process, supersonically expanded plasma jet method, induction plasma torch, reactive plasma processing, plasma electrolytic oxidation, hydrolysis method, thermohydrolysis method, coprecipitation method, citrate-nitrate autocombustion method, etc. Also applications of TiO like medical applications, environmental application, sensor application, photocatalytic applications, and also its health impact for long-term exposure are discussed. [ABSTRACT FROM AUTHOR]

In the present investigation, the microstructural and mechanical properties study of A356 alloy have been discussed. The microstructural aspect of cast A356 alloy employed in the present study is strongly dependent on the grain refinement (Ti and B) and modification (Sr). The mechanical properties such as PS, UTS, %E, %R, YM and VHN have been investigated. This paper deals with the combined effect of grain refinement and modification, which improves the overall mechanical properties of the alloy. It is also a well-known fact that the mechanical properties of cast A356 alloy were improved by subjecting suitable melt treatment such as grain refinement, modification and mould vibration, etc. The quality of castings and their properties can be achieved by refining of α-Al dendrites in A356 alloy by means of the addition of elements such as Ti and B which reduces the size of α-Al dendrites, which otherwise solidifies with coarse columnar α-Al dendritic structure. In addition, modification is normally adopted to achieve improved mechanical properties. Metallographic studies reveal that the structure changes from coarse columnar dendrites to fine equiaxed ones on the addition of grain refiner and further, plate like eutectic silicon to fine particles on addition of 0.20% of Al-10Sr modifier. The present result shows that a reduction in the size of α-Al dendrites, modification of eutectic Si and improvement in the mechanical properties were observed with the addition of grain refiner Al-3Ti, Al-3B and modifier Al-10Sr either individual addition or in combination. The change in the microstructure from coarse columnar α-Al dendrites to fine equiaxed dendrites and plate like eutectic silicon to rounded particles leads to improved mechanical properties. [ABSTRACT FROM AUTHOR]

The present paper investigates the effect of adding silica nanoparticles to an anhydride-cured epoxy polymer in bulk and when used as the matrix of carbon- and glass-fibre reinforced composites. The formation of ‘hybrid’ epoxy polymers, containing both silica nanoparticles and carboxyl-terminated butadiene-acrylonitrile (CTBN) rubber microparticles, is also discussed. The structure/property relationships are considered, with an emphasis on the toughness and the toughening mechanisms. The fracture energy of the bulk epoxy polymer was increased from 77 to 212 J/m2 by the presence of 20 wt% of silica nanoparticles. The observed toughening mechanisms that were operative were (a) plastic shear-yield bands, and (b) debonding of the matrix from the silica nanoparticles, followed by plastic void-growth of the epoxy. The largest increases in toughness observed were for the ‘hybrid’ materials. Here a maximum fracture energy of 965 J/m2 was measured for a ‘hybrid’ epoxy polymer containing 9 wt% and 15 wt% of the rubber microparticles and silica nanoparticles, respectively. Most noteworthy was the observation that these increases in the toughness of the bulk polymers were found to be transferred to the fibre composites. Indeed, the interlaminar fracture energies for the fibre-composite materials were increased even further by a fibre-bridging toughening mechanism. The present work also extends an existing model to predict the toughening effect of the nanoparticles in a thermoset polymer. There was excellent agreement between the predictions and the experimental data for the epoxy containing the silica nanoparticles, and for epoxy polymers containing micrometre-sized glass particles. The latter, relatively large, glass particles were investigated to establish whether a ‘nano-effect’, with respect to increasing the toughness of the epoxy bulk polymers, did indeed exist. [ABSTRACT FROM AUTHOR]

In this paper, large-scale uniform silver and copper nano/microtubes with high length diameter ratios have been successfully synthesized by a facile approach, using low-cost nano-scale glass fibers as templates. The tubular structures can be obtained by reducing of Ag and Cu ions on the surface of the fibers, along with removing the templates. The samples are characterized by SEM and XRD. Results show the tubular structures are very uniform and the tubular walls are composed of densely coalesced crystalline nanoparticles of 30–50 nm. [ABSTRACT FROM AUTHOR]

This paper reports on the comparative investigation of structural and optical properties of nano thin films of ZnO and Sr-doped ZnO (SZO) onto glass substrates synthesized by a two-step chemical bath deposition (CBD) technique. The mode of crystallization, structural properties, and morphologies have been investigated. The films are polycrystalline in nature with hexagonal phase having (002) preferential orientation. The typical crystallite size is also estimated and found to be around 30–80 nm. The shifts in optical band gap of the SZO films are estimated to be ∼3.25–3.27 eV with respect to the ZnO film and the refractive index is 2.35. The room temperature resistivity is of the order of ∼2,000 Ωcm. Thermoemf measurements show that films are of n-type. The sensitivity of the films was studied as a function of their temperature 275–575 K for a fixed ethanol concentration (400 ppm). The films have been tested for cross sensitivity for different gases and it has been confirmed that these are highly sensitive and selective for ethanol vapors around 200 °C in air atmosphere. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of Sb2O3 nano-particles by vapor transport and condensation of metallic antimony in oxidizing environment. Granular antimony inside an alumina crucible is placed in the middle of a tube furnace at 550 °C with air flow rate of 400 mL/min. Al foil, glass and Si-wafer, which are used as substrates, are placed downstream of the gas flow at a temperature of about 250 °C for the deposition of antimony oxide. The deposited antimony oxides on the substrates and the oxidized granular antimony in the alumina crucible are examined with field emission scanning electron microscopy, X-ray diffractometer and transmission electron microscopy (TEM). The deposited antimony oxide consists of Sb2O3 nano-particles, while the oxidized granular antimony in the crucible consists of SbO2. The mechanism of the formation of Sb2O3 nano-particles is analyzed based on oxidation reaction thermodynamics and kinetics. [ABSTRACT FROM AUTHOR]

In this paper, Ni-doped ZnO (Zn1− x Ni x O, in which 0 ≤ x ≤ 0.05) diluted magnetic semiconductors nanoparticles are prepared by an ultrasonic assisted sol–gel process. Transmission electron microscopy shows sphere-like nanoparticles with an average size of about 25 nm. From the analysis of X-ray diffraction, the Ni-doped ZnO nanoparticles are identified to be a wurtzite structure, but impurity phases are observed when the Ni content x reaches 0.05. Sample structures are further studied by Raman spectra, from which a broad and strong Raman band in the range of 500–600 cm−1 is observed in Zn1− x Ni x O. With the increment of x, wurtzite structures degrade gradually. The magnetic properties are measured using superconducting quantum interference device at room temperature; the Zn1− x Ni x O ( x ≤ 0.02) nanoparticles show ferromagnetism. However, for the sample of Zn0.95Ni0.05O, paramagnetism is observed, which may be ascribed to ferromagnetic–antiferromagnetic competition. [ABSTRACT FROM AUTHOR]

Nanohydroxyapatite reinforced poly(vinyl alcohol) gel (nano-HA/PVA gel) composites has been proposed as a promising biomaterial, especially used as an articular cartilage repair biomaterial. In this paper, nano-HA/PVA gel composites were prepared from mixing nano-HA particles modified by silicon coupling agent, with physiological saline solution (PSS) of PVA by freezing-thawing method. The effects of various factors on the mechanical properties of nano-HA/PVA gel composites were evaluated. It was shown that the mechanical behavior of nano-HA/PVA gel composites was similar to that of natural articular cartilage, which held special viscoelastic characteristics. The tensile strength and tensile modulus of the composites improved correspondingly with the increase of freezing-thawing times and concentration of PVA solution. The more concentration of PVA solution, the higher influence degree of concentration on the tensile strength of composites is. The tensile strength and tensile modulus of nano-HA/PVA hydrogel composites increased first and then decreased with the rising nano-HA content of the composites. The tensile modulus of the composites improved remarkably with the increase of elongation ratio. [ABSTRACT FROM AUTHOR]

Sm x BiY2– x Fe5O12 ( x = 0, 0.1, 0.2, 0.4, 0.6, 0.8) nanocrystals were fabricated by sol–gel method. Samples were characterized by powder X-ray diffraction (XRD), thermal gravity analysis (TGA) and differential thermal analysis (DTA), transmission electron microscopy (TEM), vibrating sample magnetometer(VSM). The samples were calcined at 850 °C and 1000 °C and the average size of the particles were determined by Scherrer’s formula . In this paper, we discussed the effect of Sm3+ substitution for Y3+ on magnetic properties of BiY2Fe5O12. The magnetic properties of Sm x BiY2−x Fe5O12 are decreased with increasing content of Sm ion. [ABSTRACT FROM AUTHOR]

The incorporation of silica nanoparticles into polyethylene has been shown to increase the breakdown strength significantly compared to composites with micron scale fillers. Additionally, the voltage endurance of the nanocomposites is two orders of magnitude higher than that of the base polymer. The most significant difference between micron-scale and nano-scale fillers is the large interfacial area in nanocomposites. Because the interfacial region (interaction zone) is likely to be pivotal in controlling properties, this paper compares the behavior of nanoscale silica/cross-linked low density polyethylene nanocomposites with several silica surface treatments. In addition to breakdown strength and voltage endurance, dielectric spectroscopy, absorption current measurements, and thermally stimulated current determinations (TSC) were performed to elucidate the role of the interface. It was found that a reduction in the mobility in nanocomposites as well as a change in the defect size may be key to explaining the improvement in the properties. [ABSTRACT FROM AUTHOR]