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In this paper, two new silicon on insulator metal-semiconductor field effect transistor (SOI-MESFET) structures are presented. Two parallel layers of oxide and aluminium are added at the gate edge of these structures. Also, in the buried oxide part of the Aluminium Edge and Silicon-Well MESFET (AESW-MESFET) structure, a silicon well and two aluminium layers are added. Moreover, and to improve the DC and RF characteristics, as compared to the Conventional MESFET (C-MESFET) structure, a silicon well and a silicon layer are added in the box oxide section in the Silicon Edge and Silicon-Well MESFET (SESW-MESFET) structure. By these changes, the value of the breakdown voltage in the normal structure has increased from 15.8 V to 33.1 V and 30.9 V in the proposed AESW-MESFET and SESW-MESFET structures, respectively. In addition, the maximum output power has been associated with a significant increase of 4.44 and 5.24 times, respectively. Compared to the C-MESFET, the proposed structures reduce gate-source and gate-drain capacitors and significantly increases conductivity. The cut-off frequency values are increased from 19.3 GHz (the normal structure) to 37.3 GHz and 35 GHz (the proposed structures), and the maximum oscillation frequencies are increased from 80 GHz to 154 GHz and 102.3 GHz. Therefore, the results show that the proposed structures have good performance and the ability to work at high power and high frequency. [ABSTRACT FROM AUTHOR]

This work aimed to develop antifouling coatings for maritime structures and sailing vessels by the integration of nanoparticles as very effective biocidal agents. The paint compositions were created by combining several components with a binder known as linseed alkyd resin. The preparation of TiO2 and SiO2 nanoparticles was conducted by the ball milling technique, followed by their application as pigments in nano paints. The corrosion characteristics of these coatings were examined after the incorporation of the nano paint, to diminish fouling and enhance antibacterial efficacy on maritime vessels. The enhancement of antifouling paint efficacy is expected to be substantial as a result of the advancement in nanoparticle-based compositions that exhibit biocidal capabilities. To evaluate the efficacy of nanocoatings, miniature specimens were submerged in a marine environment for 120 days. The coated samples underwent analysis by various techniques including scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Furthermore, an assessment was conducted to determine the efficacy of the protective characteristics exhibited by the coated tiny mild-steel samples. This evaluation involved subjecting the samples to a 120-day immersion in the ocean environment. The inclusion of SiO2 and TiO2 nanoparticles in the paints yields significant corrosion protection for the coated samples, in contrast to those lacking nanoparticles. Additionally, the latter exhibits superior anti-fouling properties. [ABSTRACT FROM AUTHOR]

Sludge from stone-cutting (SSC) factories and stone mines cannot be used as decorative stones, stone powder, etc. These substances are left in the environment and cause environmental problems. This study aim is to produce artificial stone composite (ASC) using sludge from stone cutting factories, cement, unsaturated resin, water, silicon carbide nanoparticles (SiC-NPs), and nano-graphene oxide (NGO) as fillers. Nano graphene oxide has a hydrophobic plate structure that water is not absorbed due to the lack of surface tension on these plates. NGO has a significant effect on the properties of artificial stone due to its high specific surface area and low density in the composite. Its uniform distribution in ASC is very low due to its hydrophobicity, which can be modified by using unsaturated resin and silicon carbide nanoparticles (SiC-NPs). The obtained results show a remarkable increase and improvement in the mechanical properties of the artificial stone composite in the samples containing modified NGO with SiC-NPs. These samples have less porosity, smoother, more polished surface and, high bending and compressive strength. The addition of these materials to the artificial stone has increased durability and reduced costs and has caused water repellency, and prevented the penetration of harmful ions such as chloride, etc. [ABSTRACT FROM AUTHOR]

This work investigates the bubble dynamics during pool boiling from isolated cavities on a horizontal silicon substrate with three surface coatings, silicon oxide, Perfluorodecyltrichlorosilane, and silica nanoparticles. The experiments were conducted with FC-72 under various superheat degrees. In the case of vertical coalescence, coalescences at the boundary between the departed bubble and the subsequent nucleated bubble were observed and analyzed. Vertical coalescence appears with lower superheat degrees on Perfluorodecyltrichlorosilane coated surfaces due to the faster initial bubble growth than on the other surfaces. However, the vertical coalescence has a limited effect on the bubble departure diameter, which is nearly kept constant at around 0.6 mm. In the case of horizontal coalescence, bubbles growing on the silica nanoparticles coated surface are able to coalesce for small cavity spacing with lower superheat degree than other surfaces. Coalescing bubbles from cavities spaced 0.50 mm apart can detach just after coalescence, while for a shorter spacing of 0.25 mm, bubbles remain attached to the surface and further growth is needed for their detachment. Based on the analysis of energy removal per unit of area, the optimal heat transfer performance may be achieved when the cavities spacing is approximate to the single bubble departure diameter. [ABSTRACT FROM AUTHOR]

This paper proposes a novel pixel circuit and driving scheme that adopts low-temperature polycrystalline silicon and oxide thin-film transistors (LTPO TFTs) for mobile devices using active-matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit and driving scheme provide uniform luminance and render flicker invisible at variable refresh rates (VRRs) from 1 to 120 Hz. Using the proposed pixel circuit with extended compensation time (tCOMP) improves the luminance uniformity at a high-frame rate. The proposed driving scheme applies a voltage to the driving TFTs (D-TFTs) higher than the programmed data voltage during the skip frame. This reduces the flicker caused by the hysteresis of D-TFTs during low-frame rate driving. A 6.0-inch quad high-definition (QHD) LTPO-based AMOLED display was fabricated using the new pixel circuit and driving scheme. Experimental results of the proposed pixel circuit show that the standard deviation of luminance was reduced from 0.056 to 0.008 by extending tCOMP from 2 to 8 µs. The flicker level was −51 dB, so there was no visual artifact during 1 Hz driving. A flicker-free LTPO-based AMOLED display with low power consumption is possible; driving can proceed in 1–120 Hz range. [ABSTRACT FROM AUTHOR]

Excess copper (Cu) causes the toxic effects in plants and health hazards to humans. Therefore, in this study, the effect of sodium silicate (1 mM Si) and sodium nitroprusside (200 µM SNP as a releasing NO), was assessed on Cu tolerance in Salvia officinalis L. plants exposed to 400 µM CuSO4. Results revealed that the combined supplementation with Si and SNP rather than the single application of these chemicals lowered Cu concentrations and translocation factor and increased Mg, Zn, and Fe concentrations in roots and shoots. Furthermore, combined treatment more efficiently decreased electrolyte leakage enhanced the activities of POD and APX in the leaves and roots, and improved relative water content and the content of Chl. a and Chl. b in leaves and consequently further increased tolerance index. Silicon supply enhanced NO content and applying Si + SNP more than the treatment of Si alone increased Si concentrations in the roots and shoots under Cu stress. Therefore, the reciprocal interaction of Si and NO might enhance Cu tolerance in plants, and the combined application of Si and SNP might be a promising strategy to decrease heavy metal accumulation in medicinal plants grown in polluted lands. In most studies, co-precipitation of silicon and heavy metals in medium has been suggested as a reason for reducing heavy metal uptake in plants. In this study, the impact of Si on NO generation and the role of NO signaling in regulating Cu uptake and translocation and defensive responses were assessed to clarify another mechanism of Si in inducing Cu tolerance in sage. Furthermore, the combined application of Si and SNP has been indicated as an innovative strategy to enhance Cu tolerance and decrease heavy metal accumulation in medicinal plants grown in polluted lands. [ABSTRACT FROM AUTHOR]

In the food industry, packaging is used to protect food. However, traditional packaging has serious environmental impacts. Thus, studies have investigated packaging composed of biodegradable polymers. Accordingly, the present study aimed to obtain and characterize polymeric films of sodium alginate and polyethylene glycol crosslinked with tetraethoxysilane and doped with nano-zinc oxide or nano-silicon oxide and evaluate their cytotoxicity and bactericidal activity against coliforms and Escherichia coli. The nanoparticles and crosslinked materials were characterized using infrared and Raman spectroscopy. The cytotoxicity of the films was evaluated using a direct contact assay with a bovine fibroblast cell model. The bactericidal activity of the films was assessed by determining whether the contamination indicators were activated. The average sizes of the ZnO and SiO2 nanoparticles were 408.3 and 125.3 nm, respectively, and their zeta potentials were −31.6 and −31.1 mV, respectively. Cell growth inhibition zone tests indicated that 75 ALG/25 PEG/SiO2 was slightly toxic, while 25 ALG/75 PEG/ZnO exhibited mild toxicity. Cell area analysis showed that the addition of SiO2 decreased the cytotoxicity of the obtained films. Finally, it was possible to observe the inactivation of both contamination bioindicators. Therefore, films containing nanoparticles could be promising biomaterials for packaging in the food industry. [ABSTRACT FROM AUTHOR]

The CuxOy@SiO2 nanocomposite was prepared using a pulsed plasma-chemical method. The regularities of the influence of the concentration of the starting reagents and the design of the reaction chamber on the morphology, phase composition of the CuxOy@SiO2 nanocomposite were revealed. With varying the concentration of the starting reagents, the agglomeration of particles decreased, the particle morphology (particles acquired a spherical shape) and phase composition (the predominant crystalline phases were CuCl2, CuCl, Si, CuO, Cu) changed. Two types of reaction chambers (quartz/copper) were used for the synthesis of the CuxOy@SiO2 nanocomposite. The change in the design of the reaction chamber had an insignificant effect on the phase composition of the CuxOy@SiO2 composites, but had a strong effect on the morphology and average size of the synthesized particles. The morphology of the composite particles prepared in a copper reactor is represented by particles of a fine fraction of an irregular shape. [ABSTRACT FROM AUTHOR]

Nowadays, multifunctional finishing processes become important in the textile industry. This approach generally ensures less chemical and energy consumptions with less process durations. In this study, it was planned to produce water repellent and antibacterial cotton fabrics by using a single-stepped finishing process. To ensure water repellency and antibacterial efficiency, cotton fabrics were impregnated with a solution containing both nano titanium silicon oxide and fluorocarbon-based water repellent in different concentrations. After finishing cotton fabrics with so-called solution the samples were then tested in terms of water repellency and antibacterial efficiency. In addition, to see the changes in whiteness during processes, the whiteness (stensby) values of the treated cotton fabrics were measured too. In terms of testing antibacterial efficiency two different types of bacteria; a Gram-positive (Staphylococcus aureus) and a Gram-negative (Escherichia coli) bacteria, were used. As a result of the study, it was observed that cotton fabrics can gain water repellency and antibacterial activity against Staphylococcus aureus has occurred. Meanwhile a limited antibacterial activity against Escherichia coli was found too. [ABSTRACT FROM AUTHOR]

Exposure to different nanoforms (NFs) via the dermal route is expected in occupational and consumer settings and thus it is important to assess their dermal toxicity and the contribution of dermal exposure to systemic bioavailability. We have formulated four grouping hypotheses for dermal toxicity endpoints which allow NFs to be grouped to streamline and facilitate risk assessment. The grouping hypotheses are developed based on insight into how physicochemical properties of NFs (i.e. composition, dissolution kinetics, size, and flexibility) influence their fate and hazard following dermal exposure. Each hypothesis is accompanied by a tailored Integrated Approach to Testing and Assessment (IATA) that is structured as a decision tree and tiered testing strategies (TTS) for each relevant question (at decision nodes) that indicate what information is needed to guide the user to accept or reject the grouping hypothesis. To develop these hypotheses and IATAs, we gathered and analyzed existing information on skin irritation, skin sensitization, and dermal penetration of NFs from the published literature and performed experimental work to generate data on NF dissolution in sweat simulant fluids. We investigated the dissolution of zinc oxide and silicon dioxide NFs in different artificial sweat fluids, demonstrating the importance of using physiologically relevant conditions for dermal exposure. All existing and generated data informed the formulation of the grouping hypotheses, the IATAs, and the design of the TTS. It is expected that the presented IATAs will accelerate the NF risk assessment for dermal toxicity via the application of read-across. [ABSTRACT FROM AUTHOR]

The application of scientific and technological studies prior to the repair of historic and ancient ceramics can provide a more complete understanding of glazes to aid the conservator's decision-making process before undertaking the conservation of ceramics. There are two categories of Chinese glaze morphology for general high-temperature single-color glazes, calcium glazes (smooth glazes), and calcium alkali glazes (glazes containing more bubbles or crystals and multiple glazes). High-temperature colored glazes can be divided into four types: on-glazed, in-glazed, diffused, and under-glazed pigments. The subdivision of high-temperature glaze types has significance as a guiding factor in the repair of historic and ancient ceramic glazes. Optical coherence tomography (OCT) is discussed as a non-invasive way to understand glaze structure and as a tool to aid the conservator in the treatment of ceramics. Moreover, a silica sol-acrylic composite coating was studied as a possible material to use in the replication of ceramic glazes on areas of restoration. A small amount of acrylic resin can improve the reversibility of the synthetic coating. On the macro level, this coating exhibits natural glaze bubbles and craquelure similar to historic and ancient ceramics; in addition, on the micro level, it can imitate the clean calcium glaze and crystallization calcium alkali glaze of such ceramics. The silicon oxide content in this glaze-like material is found to be similar to that of historic and ancient ceramics. [ABSTRACT FROM AUTHOR]

SiC power MOSFETs were exposed to 79Br, 64Cu, and 47Ti ions with different biases. After irradiation, the static parameters of the device did not change significantly. The oxide reliability is also not affected after ON-state irradiation. However, noticeable degradation of gate oxide reliability has been found after heavy-ion exposure with extremely low drain bias(50 V). The degradation is attributed to defects in the gate oxide. According to the analysis of the experimental results, the defects are caused by the high electric field induced by the partial SEGR effect during heavy-ion irradiation. [ABSTRACT FROM AUTHOR]

This work developed a novel approach for carbon nanotube (CNT) direct deposition on carbon fiber (CF) tow surface by chemical vapor deposition (CVD), without degrading CF mechanical properties. This approach combines conditions for growth at lowtemperature (650°C), small growth induction period for a fast growth and fast surface modification to enable the growth. The lower growth temperature comes from using the well-known equimolar C2H2/CO2 gas mixture. The floating catalyst from a liquid precursor (with high ferrocene concentration dissolved in hexane) reduced the growth induction period. Gentle surface modification, either by a mild oxidation of CF fiber with silicon containing sizing, or by desized CF exposition to a hexamethyldissiloxane (HMDSO) environment, create silicon oxide clusters. The X-ray Photoelectron Spectroscopy (XPS) analysis show that such clusters need to be in a higher oxidation state - Si(-O)2, Si(-O)3 and Si(-O)4 - to anchor catalyst and enable CNT growth. The first oxidation state - Si(-O)1 - is not enough. A resin droplet wetting test developed shows that even though the success in CNT growth, the entire processes decrease CF wetting, exposing the need for a resizing procedure. CF mechanical properties were characterized by single-filament and CF tow tensile strength tests. [ABSTRACT FROM AUTHOR]

Due to the rapid development of China and the increasing demand for various minerals, the accidents of mine operations have occurred frequently in recent years, which have caused a huge obstacle to the safety of the people's lives and the prosperity and prosperity of the country. Not to be ignored, the response is also imminent. Based on the above background, this paper aims to study the safety of nano-material powder control technology on mine gas explosion suppression. In order to further analyze the influence of nanomaterials on explosion suppression and the improvement of safety performance, the flame propagation and pressure characteristic parameters of gas explosion were selected to evaluate the safety performance. In this paper, nano-calcium carbonate and nano-silica are selected for explosion suppression experiments. According to the gas explosion theory, the smaller the particle size of the powder, the better the explosion suppression effect. Silicon oxide's small size effect, interface effect, photoelectric characteristics, etc., enhance the powder's anti-explosion performance. In the experiment, by adding powder, it was verified that the safety of nano-powder control technology for gas explosion suppression was improved. This article combines powder control technology with nano-materials, making full use of the powder properties of nano-materials, and studying their improvement of the safety performance of gas explosion suppression. [ABSTRACT FROM AUTHOR]

A two-dimensional (2D) channel potential distribution is analytically derived for lightly doped double-gate MOSFET at turn-on condition of the device by solving 2D Poisson's equation with the application of suitable boundary condition. Threshold voltage roll-off is also modelled to predict the short channel behaviour of the device at sub-threshold condition. Our derived model closely follows the 2D numerical simulation without the inclusion of any fitting parameters. It also serves as a basic step towards computing the compact modelling of DG MOSFET at threshold condition. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA) eye drop solution is widely used to treat and manage various corneal diseases like keratoconus (after corneal cross-linking) and dry eye syndrome. However, ocular dosage forms like eye drop solution affect the routine life style of patients due to frequent dosing schedule. In this study, HA and reduced graphene oxide (rGO) was directly loaded in the silicon contact lenses (HA-GO-DL) and compared with the conventional soaking method (HA-GO-SM). The contact lenses at lower level of rGO showed permissible swelling and transmittance properties. The water retention property of HA-GO-DL contact lenses was confirmed by water evaporation studies. The flux data of HA-GO-SM contact lenses showed high burst release with 24 h release duration. While, HA-GO-DL lenses confirmed low burst with sustained release up to 96 h. In ocular irritation study, the HA-GO-DL-2 lenses was found to be safe. The HA-GO-DL-2 batch showed high HA-tear fluid concentration (rabbit model) and improvement in the rabbit tear fluid volume (Schirmer strip studies) in comparison to the soaking method (HA-GO-SM-2) and eye drop solution. The study successfully demonstrate the potential of HA-GO loaded contact lenses to improve tear fluid volume to manage various ocular diseases like dry eye syndrome. [ABSTRACT FROM AUTHOR]

In this work, the multicomponent nanocomposites containing filamentary carbon nanostructures were synthesized using materials based on iron oxides with a predominant content of the epsilon phase (ε-Fe2O3). These iron oxide-based materials were obtained by a direct plasma-dynamic synthesis with supersonic outflow of an iron-containing electric discharge plasma into an oxygen atmosphere. Subsequently, they were used as an initial precursor and placed in the plasma-chemical reactor, where the multicomponent C/SixOy/Fe2O3 nanostructures were synthesized under the influence of the pulsed electron beam. This method was based on the volume excitation of the reaction gas by a pulsed electron beam in such a way as to control the uniform process implementation in the entire excitation region. The morphology and phase composition of the synthesized C/SixOy/Fe2O3 nanocomposites were studied. A typical morphological feature of the C/SixOy/Fe2O3 samples was found to be the formation of filamentary nanostructures. Their diameter does not exceed 10–20 nm, while their length varies up to 1 μm. [ABSTRACT FROM AUTHOR]

In this study porous silicon/graphene-based nanostructures were prepared by deposition of the graphene oxide and the reduced graphene oxide on the porous silicon layer. The charge transport in obtained structures was analyzed on the basis of temperature dependencies of the conductivity in the 12–300 K range within the model of disordered semiconductors. Hopping conductivity and activation mechanism of charge transport in different temperature ranges were established and the activation energy of the conductivity was determined. The deposition of the graphene and graphene oxide nanosheets on the porous silicon surface changes the limits of these ranges toward lower temperatures. The impedance spectra of PS/graphene-based structures were measured in the 25 Hz − 1 MHz frequency range in the wide temperature range. A decrease in electrical capacitance with increasing the frequency and an increase in impedance at lowering the temperature were revealed. [ABSTRACT FROM AUTHOR]

This work examines the effect of particle size of silicon oxide (SiO2) nanoparticle on the emissions characteristics of four-stroke, single cylinder water-cooled diesel engine fueled with neat diesel (D100). Silicon oxide as an additive in various particle-size of 10 nm and 20 nm is included to D100 and termed as D100SiO210 and D100SiO220. The experimental result proved that the CO and HC emissions are 3.3% and 3.7% lower for D100SiO210 than D100 at 3.5 bar BMEP. SiO2 nanoparticle further reduces CO and HC emissions by 3.2% and 2.6% correspondingly for D100SiO220 than D100. The degree of NOx emission in D100 is 4.6% higher at 3.5 bar BMEP. When compared to D100, tailpipe NOx emission was found to be 1.7% and 2.6% lower when fueled with D100SiO210 and D100SiO220. In addition, the tailpipe smoke emission was found to be 0.7% lower when fueled with D100. [ABSTRACT FROM AUTHOR]

Three sets of carbon-containing nanocomposites based on titanium dioxide were synthesised by changing the concentrations of the original precursors (Сн4, о2) using a pulsed plasma chemical method. The elemental and chemical analyses of the synthesised nanocomposites were performed. The morphology of the carbon-containing titanium dioxide-based nanocomposites was studied by transmission electron microscopy. To determine the crystal structures of the nanocomposites, the standard method of X-ray phase analysis was used. The band gaps for the synthesised carbon-containing titanium dioxide-based composites were calculated using the diffuse reflectance spectra in the range of 1.3–3.6 eV. It was experimentally proved that the band gap for indirect transitions depended on the total carbon content in the synthesised samples and was 2.76 eV for some samples. [ABSTRACT FROM AUTHOR]

In recent studies, polyurethane has shown multiple properties that make it an excellent candidate material in 4D printing. In this study, we present a simple and inexpensive additive method to print waterborne polyurethane paint-based composites by adding carboxymethyl cellulose (CMC) and silicon oxide (SiO2) nanoparticles to the paint. The first function of CMC and SiO2 is to improve rheological properties of the polyurethane paint for making a printable precursor, which improves the printing resolution and enhances additive manufacturability. Second, the composite precursors improve the curing rate of the polyurethane paint without changing its inherited shape memory properties. Third, the printed composite parts shown enhanced mechanical strength compared with that of the parts printed with pure polyurethane. Finally, the 3D printed polyurethane-CMC and SiO2 parts exhibit time-resolved shape transformation upon heat stimulation. To the best of our knowledge, this is the first study of using the polyurethane paint as the precursor for 4D printing, which would open new possibilities in future applications in biomedical engineering, soft robotics and so on. [ABSTRACT FROM AUTHOR]

This work experimentally investigated silicon oxide and aluminum (III) oxide nanoparticles as enhanced oil recovery agents and their effects on wettability and interfacial tension of oil-wetted sandstone and carbonate rocks. The two nanoparticles were selected based on a screening of commercially available nanoparticles with considering the most important parameters. The required time and treatments for the rock samples to become oil-wet, and the required time for the nanofluid to treat each rock sample were also experimentally investigated. Results of this study show that the nanoparticles alter wettability of sandstone and carbonate rocks from oil-wet to water-wet state. It is also observed that sandstone samples are more effected than limestone ones and alumina nanoparticles have greater potential to alter the rock wettability. [ABSTRACT FROM AUTHOR]

A freestanding SiO2-TiO2 monolith with bicontinuous structure was prepared via a one pot sol-gel reaction. This monolith was fully characterized by using field emission scanning electron microscopy (FE-SEM), nitrogen adsorption and X-Ray diffraction (XRD). Synthesized SiO2-TiO2 monolith possesses great mechanical strength and interconnected macropores (throughpores, textural pores) on the micrometer scale as well as skeleton pores in nanoscale, and also possesses an anatase TiO2 crystalline structure. Photo-catalytic breakdown of aqueous methylene blue (MB) with UV light was chosen to evaluate photocatalytic efficacy of the SiO2-TiO2 catalyst. These photodegradation activities indicated that MB decomposed completely within 180 min and the SiO2-TiO2 catalyst was readily separated from the reaction system and easily regenerated. Moreover, the photocatalytic activity of the monolithic catalyst remained unchanged after four catalytic cycles and the morphology was still intact. [ABSTRACT FROM AUTHOR]

A pulsed plasmochemical method was used to obtain carbon-containing nanocomposites based on silicon oxide modified with titanium dioxide. The material contained a SixCyOz carrier with an average size of 50-150 nm and a shell of fine particles with an average size of 5-10 nm. The phase composition and morphology of the synthesized composites was studied by X-ray diffraction and transmission electron microscopy. The optical and photocatalytic properties of the nanoparticles from the carbon-based composite based on silicon oxide encapsulated in titanium dioxide were studied. The synthesized composite showed a high photocatalytic activity due to the decomposition of methylene blue under the influence of visible light in the wavelength range of 460-630 nm. [ABSTRACT FROM AUTHOR]

Protecting groups are indispensable in organic synthesis and there is a great need for a variety of deprotection methods. Here, we investigated the scope of the application of a deprotection procedure using SO3H silica gel, which we have previously reported as a desilylation procedure. Under these conditions, -OMOM, -OSEM, -OTHP, and -OAc groups and dimethyl acetal were cleaved. Pivaloyloxy, benzyloxy and methoxy carbonyl groups remained intact and selective deprotection of TBS groups in the presence of other protecting groups was accomplished. We succeeded in cleaving an acetyl group on a secondary alcohol in a highly polar nortropine derivative. Our findings here provide another deprotection option and would be helpful in the synthesis of multifunctional compounds. [ABSTRACT FROM AUTHOR]

This paper comprises a comprehensive kinetic study for the adsorptive removal of As (V) from aqueous medium by mixed oxide (MO) of iron and silicon. The multi-linearity of the intraparticle diffusion model pointed towards the likelihood of both the pore and film diffusion. The Boyd model validated film diffusion to be the principal mechanism responsible for controlling the rate of the arsenate adsorption on MO. The negative entropy of activation (ΔS#) suggested the adsorption mechanism to be associative in nature. The non-negative values of ΔG# suggested the presence of an energy barrier to be surmounted for the reaction to occur. [ABSTRACT FROM AUTHOR]

In this study hybrid structures were created by deposition of the graphene oxide and the reduced graphene oxide on the porous silicon layer. The charge transport and relaxation processes in obtained structures were analyzed on the basis of comprehensive studies of conductivity and depolarization current in the 90–325 K temperature range within the model of disordered semiconductors. Hopping conductivity and activation mechanism of charge transport in different temperature ranges were established and the activation energy of the conductivity was determined. Localized electron states that affect the charge transport in the porous silicon/graphene-based structures were found by means of thermally stimulated depolarization spectroscopy. It has been revealed that the adsorption of water molecules changes resistive and capacitive parameters of hybrid structures. Found features of the charge transport processes expand the prospects of application of such nanomaterials for sensor electronics. [ABSTRACT FROM AUTHOR]

The Tuncang-Chuzhou-Machang area (eastern Anhui province) is geologically located in the intersection between the Yangtze block and the Qinling-Dabie orogenic belt. Many Mesozoic plutons outcrop in this district that are Cu-Au prospective but inadequately studied. We report new LA-ICP-MS zircon U-Pb ages, petrologic, and whole rock geochemical data for three representative plutons at Machang, Huangdaoshan, and Tuncang. New dating results suggest that all the Machang (129.3 ± 1.6 Ma), Huangdaoshan (129 ± 1.7 Ma), and Tuncang (130.8 ± 1.9 Ma) plutons were emplaced in the Early Cretaceous, slightly older than other plutons in neighbourhood of the Zhangbaling uplift. The three plutons contain typical low-Mg adakitic affinities, in which the rocks contain SiO2 >56%, Al2O3 ≥15%, Mg# <53, elevated Sr, Ba, Cr, Ni, Sr/Y, and La/Yb, low Y and Yb and no discernible Eu anomaly. Their petrogenesis may have been related to the delamination and partial melting of the lower crust, which is different from the Chuzhou pluton, which was interpreted to have formed by partial melting of the subducted slabs. We suggest that this petrogenetic difference may explain why the pluton at Chuzhou is Cu-Au fertile, whereas those at Machang, Huangdaoshan, and Tuncang are largely barren. It is proposed that adakitic plutons formed by partial melting of the subducted slabs have high metallogenetic potentiality in the area. [ABSTRACT FROM AUTHOR]

The Beihuaiyang Zone (BHY) is one of the most important Mo-Pb-Zn polymetallic metallogenic belts in China, and the BHY deposits are genetically and geographically associated with Cretaceous magmatic rocks. In this article, we present new zircon U-Pb ages and Hf isotope data, whole-rock major and trace-element analytical results, and Sr-Nd-Pb isotope data for the granite porphyry of the Shapinggou (SPG) Mo deposit and the quartz monzonite porphyry of the Gongdongchong (GDC) Pb-Zn deposit. The high contents of SiO2, crust-like rare-earth-element and trace element patterns, and the enriched Sr-Nd-Pb-Hf isotopic compositions indicate that both porphyries originated from crustal melting. Inherited Neoproterozoic zircons are common in both porphyries, which implies that their crustal sources were the South China Block rather than the North China Block. Whole-rock εNd(t) values (−10.8 to −9.8 for the GDC deposit, −12.9 to −12.4 for the SPG deposit) and zircon εHf(t) values (−14.3 to −11.1 for the GDC deposit, −18.4 to −13.3 for the SPG deposit) for the ore-bearing rocks are significantly higher than the values found in the widespread and older ore-barren rocks, indicating that the magma sources of the ore-bearing rocks were younger than those of the ore-barren rocks. An integrated study of the Sr-Nd-Pb-Hf isotope contents shows that these younger source rocks are similar to the gneisses found in the South and Central Dabie units, which represent the upper crust of the subducted South China Block. Given the geochemical behaviour of molybdenum, a surface enrichment process would have been an essential prerequisite for the formation of the large Mo deposit. The early Paleozoic Mo-Pb-Zn-enriched black shales, which are widespread in the upper layers of the South China Block, might have been scraped off during Triassic subduction and then transported to deep-crustal levels below the BHY, thus forming an ideal source for the ore-bearing porphyries. An upper-crustal origin for the ore-bearing magmatic rocks is also consistent with the data for most other deposits distributed in the BHY of the Dabie Orogen. [ABSTRACT FROM AUTHOR]

Pd-doped SiO2 organic-inorganic hybrid materials were synthesized using sol-gel technique. The Pd-doped SiO2 samples were calcined at the temperature 350°C for several different time in air atmosphere with two different heating rates. Influence of calcination time and heating rate on the phase-chemical structure of Pd-doped SiO2 membrane materials was discussed by XRD, XPS, FTIR and TG-DTG analysis. The results indicate that the two factors have great influence on the crystal structure of Pd element and minor influence on the chemical structure. A longer calcination time and a slower heating rate can facilitate the oxidation of Pd0 to PdO, and should be conducive to the decomposition of Si-CH3 groups and the dehydration condensation of Si-OH groups. In order to prevent metallic Pd0 in Pd-doped SiO2 organic-inorganic membrane materials from being oxidized in air, the calcination time and heating rate should be chosen carefully. [ABSTRACT FROM AUTHOR]

In this work, poly(L-lactic acid) film was coated with SiOxby the plasma-enhanced chemical vapor deposition with different deposition times. Compared with the neat poly(L-lactic acid) film, the oxygen (O2), carbon dioxide (CO2), nitrogen (N2), and water vapor permeability of the poly(L-lactic acid)/SiOx60 film (depositing for 60 min) decreased by 40.7, 30.6, 58.7, and 53.4% at 25°C, respectively. After treated by the SiOxdeposition, the gas permselectivity of the poly(L-lactic acid)/SiOx60 film, such asα(CO2/O2),α(O2/N2), andα(CO2/N2), increased by 17.2, 43.9, and 67.5% at 25°C, respectively. In addition, Young’s modulus and tensile strength of poly(L-lactic acid)/SiOx60 film increased by 107.2 and 49.3%, respectively. Moreover, the poly(L-lactic acid)/SiOx60 films still kept good toughness with an elongation at break of 50.7%. [ABSTRACT FROM PUBLISHER]

In this work, we investigated the influence of piezoelectric ZnO and nonpiezoelectric SiO2 and TiO2 nanoparticles on the structure and some physical properties of composite structures based on microtubes of diphenylalanine. We demonstrated that all types of used nanoparticles promoted formation of voids and cavities in diphenylalanine microtubes thus reducing the effective Young's modulus and lateral piezoelectric coefficient of the composite. At the same time, embedding of piezoelectric ZnO nanoparticles provides noticeable vertical piezoresponse normally absent in single-component diphenylalanine microtubes. The obtained results demonstrate the ability to control the properties of self-assembling composite biomaterials by nanoparticles. [ABSTRACT FROM AUTHOR]

As novel materials for food contact packaging, inorganic silicon oxide (SiOx) films are high barrier property materials that have been developed rapidly and have attracted the attention of many manufacturers. For the safe use of SiOxfilms for food packaging it is vital to study the interaction between SiOxlayers and food contaminants, as well as the function of a SiOxbarrier layer in antioxidant migration resistance. In this study, we deposited a SiOxlayer on polylactic acid (PLA)-based films to prepare SiOx/PLA coated films by plasma-enhanced chemical vapour deposition. Additionally, we compared PLA-based films and SiOx/PLA coated films in terms of the migration of different antioxidants (e.g.t-butylhydroquinone [TBHQ], butylated hydroxyanisole [BHA], and butylated hydroxytoluene [BHT]) via specific migration experiments and then investigated the effects of a SiOxlayer on antioxidant migration under different conditions. The results indicate that antioxidant migration from SiOx/PLA coated films is similar to that for PLA-based films: with increase of temperature, decrease of food simulant polarity, and increase of single-sided contact time, the antioxidant migration rate and amount in SiOx/PLA coated films increase. The SiOxbarrier layer significantly reduced the amount of migration of antioxidants with small and similar molecular weights and similar physical and chemical properties, while the degree of migration blocking was not significantly different among the studied antioxidants. However, the migration was affected by temperature and food simulant. Depending on the food simulants considered, the migration amount in SiOx/PLA coated films was reduced compared with that in PLA-based films by 42–46%, 44–47%, and 44–46% for TBHQ, BHA, and BHT, respectively. [ABSTRACT FROM PUBLISHER]

The physico-chemical properties of three clays (reddish, yellow and gray) collected at Ha Motloheloa quarry in Lesotho were determined. The main components in all the clays were SiO2, Al2O3, Fe2O3and K2O in the form of mica, CaO, MgO, Na2O, TiO2and P2O5with less than 6% loss of ignition (LOI). The clays showed a wide variation in particle sizes with clay fractions from 15.81% to 27.38%, silt fractions from 41.95% to 52.32% and sand fractions from 30.6% to 31.9%. The surface area of the clays increased with a decrease in particle size. All the clays showed water content below 9% and shrinkage value below 6%. The clays had moderate plasticity indexes between 20 and 25 and less than 9% water content with 17.32%–20.72% water required to produce sufficient workability. Their densities were less than 3 g/cm−3and had low green to dry shrinkage (4.19%–5.35%). For all firing temperatures used (950°C–1100°C), the flexural strength varied from 2.3 to 17.6 MPa, while the water content varied from 6.1% to 12.2%. The reddish clay can be used for making perforated/solid bricks and roofing tiles, while yellow and gray clays can be used only for solid bricks. [ABSTRACT FROM PUBLISHER]

Tungsten chemical-mechanical polished integrated circuits were used to study the alignment and immobilization of mammalian (Vero) cells. These devices consist of blanket silicon oxide thin films embedded with micro- and nano-meter scale tungsten metal line structures on the surface. The final surfaces are extremely flat and smooth across the entire substrate, with a roughness in the order of nanometers. Vero cells were deposited on the surface and allowed to adhere. Microscopy examinations revealed that cells have a strong preference to adhere to tungsten over silicon oxide surfaces with up to 99% of cells adhering to the tungsten portion of the surface. Cells self-aligned and elongated into long threads to maximize contact with isolated tungsten lines as thin as 180 nm. The orientation of the Vero cells showed sensitivity to the tungsten line geometric parameters, such as line width and spacing. Up to 93% of cells on 10 μm wide comb structures were aligned within ± 20° of the metal line axis. In contrast, only ~22% of cells incubated on 0.18 μm comb patterned tungsten lines were oriented within the same angular interval. This phenomenon is explained using a simple model describing cellular geometry as a function of pattern width and spacing, which showed that cells will rearrange their morphology to maximize their contact to the embedded tungsten. Finally, it was discovered that the materials could be reused after cleaning the surfaces, while maintaining cell alignment capability. [ABSTRACT FROM AUTHOR]

n-Si/SiO2(Cu) structures with different morphologies of copper deposits are produced using the template synthesis method. Deposition of Cu nanostructures and their structural features is thoroughly studied, and mechanisms for the formation of compact and dendrite-like deposits in the pores of the SiO2 template on the n-type single-crystal silicon substrate are established. Spatially separated copper dendrites are obtained and used to investigate the efficiency of Raman scattering enhancement using the aqueous solution of the Rhodamine 6G dye. [ABSTRACT FROM AUTHOR]

The wettability property of silica (SiO2) substrate by the ethanol molecules may play important roles in nanomedicine and nanomaterials fabrication. In this paper, by molecular dynamics (MD) simulations, we show that ethanol molecules can form an ordered monolayer on hydroxylated β-cristobalite SiO2 (1 1 1) substrate, therefore an ethanol droplet can form on this ordered monolayer. We found that water molecules could affect the formation of ethanol monolayer on SiO2 surface when the amount of water molecules is large, thus regulates the wetting transformation of ethanol molecules. The absorbed water molecules would disrupt the ordered ethanol monolayer and the ethanol molecules could not form the droplet. [ABSTRACT FROM AUTHOR]

The absorption spectra of CO and CO2confined in nanopores of SiO2/Al2O3xerogel have been measured using a Bruker IFS-125 HR Fourier spectrometer. Dependences of the half-width values on rotational quantum numbers and the line shift mean values are studied and compared with the data available in literature. Possible causes which can affect the rotational dependences are discussed. [ABSTRACT FROM AUTHOR]

The production of modified asphalt mixtures with appropriate performance in high temperature has always been under the attention of researchers. One of these modifiers is Styrene Butadiene Styrene (SBS) polymer. Since the application of SBS polymer in bitumen and asphalt mixture does not have expected performance of field due to phase separation of bitumen and polymer, oxidation, and aging, the present study tries to not only improve the polymer defects, but also analyzes its high-temperature performance by using nano-SiO2and SBS polymer in bitumen modification. According to the study results, adding nano-SiO2and SBS polymer with 3 and 4.5 bitumen weight percent, respectively, to bitumen in asphalt mixture leads to an increase of flow number in dynamic creep test at 50°C for 399 times and at 60°C for 1,015 times compared to unmodified asphalt mix. This, in turn, indicates the considerable improvement of asphalt mixture high-temperature performance. [ABSTRACT FROM AUTHOR]

An efficient synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives is accomplished in aqueous media by a three-component reaction of isatoic anhydride, primary amines or ammonium acetate, and aldehydes catalyzed by titanium silicon oxide nanopowder. A variety of 2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized using this methodology in good to excellent yields. The catalyst was recovered and recycled up to four times without significant loss in the catalytic activity. [ABSTRACT FROM AUTHOR]

The kinetics of heterogeneous catalytic ozone decomposition in aqueous solution over composite iron-manganese silicate oxide (FMSO) was investigated. Results showed that the presence of FMSO significantly accelerated the ozone decomposition rate from 0.022 (without FMSO) to 0.101 min−1. The effects of inorganic anions and solution pH indicated that surface hydroxyl groups on FMSO were the active sites for catalyzing ozone decomposition and neutral charge surface seemed to show the highest catalytic performance. Tert-butanol inhibition experiments demonstrated that FMSO effectively accelerated the transformation rate of ozone into hydroxyl radicals. The contribution of hydroxyl radicals on ozone decomposition with and without FMSO was subsequently determined. [ABSTRACT FROM PUBLISHER]

In this study, we investigated the effect of SiO2lenses on the output power of InGaN/GaN-based vertical light-emitting diodes (VLEDs; wavelength = 445 nm) and compared the results to those of reference VLEDs without the SiO2lenses (planar samples). Arrays of SiO2lenses (pitch = 3 μm, width = 2.5 μm, height = 1.0 μm) were formed on c-plane sapphire substrates. The external quantum efficiency (EQE) of the packaged VLEDs with planar and patterned substrates was characterised. At 5 mA, the EQE of the patterned samples was 150% higher than that of the planar samples. A patterned, N-polar,n-GaN sample contained far fewer nanopipes (approximately 2.2 × 105 cm−2) than a planarn-GaN sample (approximately 2.4 × 106 cm−2). Furthermore, the patterned samples contained far fewer threading dislocations (approximately 1.0 × 108 cm−2) than the planar samples (approximately 5.0 × 108 cm−2). Scanning electron microscopy (SEM) images showed that the photoelectrochemical (PEC)-etched patterned samples contained cones that were 150% larger than that of the PEC-etched planar samples. In addition, SEM images, cathode luminescence measurements and finite-difference time-domain simulations were used to characterise the improved light output of the patterned samples. [ABSTRACT FROM PUBLISHER]

In this work, we synthesized and characterized mesoporous thin films of SiO2and NiTiO3structured by a surfactant called Brij58. These films were fabricated by the method of dip coating and the best conditions for well-structured thin films were investigated as a function of surfactant concentration and different types of substrates. These films have been characterized by X-ray reflectivity which was calculated using the matrix formalism. We demonstrated that the silicon substrate had a great effect on the structure and porosity of the fabricated films for both SiO2and NiTiO3. Furthermore, we found that mesoporosity has been increased as a function of the surfactant concentration in the solution. This experimental procedure allows also to produce NiTiO3powders which have been characterized by X-ray diffraction. The XRD coupled to the crystallographic software “Maud”shows that the samples are constituted by 98, 2% NiTiO3powders. [ABSTRACT FROM AUTHOR]

Although silicon (Si) is the second most abundant element of the earth's crust and in soils, it is not listed among the essential elements for plants. However, the beneficial role of Si in stimulating the growth and development of many plant species has been recognized. This study investigated the effects of in vitro application of nanosilicon oxide on growth and proliferation of apple rootstock MM106 in tissue culture. The experiment included five levels nanosilicon oxide (0, 25, 50, 100, and 200 mg/L) added to Murashige and Skoog medium. The results showed that using nanosilicon increased in fresh and dry weights, length and number of branches, and chlorophyll in explants with the highest increase being at 100 mg/L. Growth suppression occurred at 200 mg/L. This investigation showed that 100 mg/L silicon oxide can be added to Murashige and Skoog medium for fast growth and proliferation of MM106 apple rootstock explants. [ABSTRACT FROM AUTHOR]

Effective and timely heat removal from high-power light-emitting diodes (LEDs) is crucial to their performance and lifetime. The strategy of using a screen mesh wick heat pipe with SiO2nanofluid as the working fluid for LED heat dissipation is comprehensively evaluated. An experimental system is set up to study the heat transfer performance of the heat pipe. The obtained experimental results give optimal conditions/parameters for the heat pipe: 60% charging ratio, 30° incline angle, and 1wt% concentration of the nanofluid. Compared with a heat pipe using the secondary distilled water as the working fluid, the thermal resistance of the heat pipe using the SiO2nanofluid as the working fluid is generally reduced by around 35–40% for the investigated heat load range of 1–60 W. Based on an equivalent heat conductivity of the SiO2nanofluid heat pipe derived from the experimental results, an Icepak modeling effort for the cooling system of a 60-W LED lamp is then expended. The numerical results show that the temperature of the LED lamp remains low and quite uniform across the LED chip region, indicating the technical feasibility of using this class of heat pipes for cooling of high-power LEDs. [ABSTRACT FROM PUBLISHER]

The paper proposes protective silicon-silicon oxide thin film for integrated optical circuits (IOC) based on lithium niobate. Threshold values for silicon layer thickness were experimentally determined. Silicon-silicon oxide layers were deposited on IOC samples with combination of DC unipolar pulsed magnetron sputtering, reactive magnetron sputtering, and plasma enhanced chemical vapor deposition with inductively coupled plasma source (ICP-PECVD). Selection of proper deposition regimes allowed us to obtain thin films demonstrating no attenuation of optical signal. [ABSTRACT FROM AUTHOR]

PS binary porous structure membrane with big pores on the surface and small pores in the bottom was prepared combine BF method and colloidal crystal template method. Therefore, the big pore size can be controlled by BF conditions, while the small size adjusted by Si02 particles size. Compared with membrane prepared only using BF method, the binary porous structure membranes with high permeability possess potential applications in microfiltration. [ABSTRACT FROM AUTHOR]

A SiO2/Al2O3/Sb2O5mixed oxide was synthesized via a sol-gel method and applied to the on-line preconcentration of Ni(II) with determination by flame atomic absorption spectrometry. The mixed oxide was characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, thermogravimetric analysis, and the specific surface area. Analysis was performed by percolating 20.0 mL of sample at pH 7.1 through 100 mg of SiO2/Al2O3/Sb2O5packed into a mini-column at 9.5 mL min−1. Under the optimum conditions, a preconcentration factor of 77.5-fold, linear dynamic range from 5.0 to 270.0 µg L−1, and limits of detection and quantification of 0.48 and 1.61 µg L−1were obtained. The effects of several concomitant ions were evaluated and no interferences were observed. The method was employed for the analysis of water with good recoveries (92.9–100.6%) and the accuracy was verified by using a marine sediment certified reference material (MESS-3). [ABSTRACT FROM AUTHOR]

Spherical silica nanoparticles containing Rhodamine 6G dyes were prepared using an improving Stober method. The nanocomposites were almost mono-dispersed. Excitation and emission peaks of entrapment of Rhodamine 6G dye molecules in the silica matrix showed no obvious shift compared with that of Rhodamine 6G. The photostability of Rhodamine 6G doped SiO2 nanoparticles was enhanced by about three times in solution. From lung cancer cells uptake of Rhodamine 6G doped silica nanocomposites, it was concluded that nanocomposites were incorporated into these cells. [ABSTRACT FROM AUTHOR]

Superhydrophobic coatings based on PDMS and TiO2-NPs/SiO2- NPs were prepared. Due to the photocatalytic property of TiO2-NPs, th e PDMS/TiO2-NPs coatings could remove the organic pollutes efficiently, and showed an excellent self-cleaning properties. The superhydrophobicity of the PDMS/TiO2-NPs coatings was still remained after 6 months in the open air, which is much better than the PDMS/SiO2-NPs coatings. [ABSTRACT FROM AUTHOR]