pinecone/core-2020-05-10-deduplication huggingface dataset:
Vibration Damping of Carbon Nanotube Assembly Materials

Vibration reduction is of great importance in various engineering
applications, and a material that exhibits good vibration damping along with
high strength and modulus has become more and more vital. Owing to the superior
mechanical property of carbon nanotube (CNT), new types of vibration damping
material can be developed. This paper presents recent advancements, including
our progresses, in the development of high-damping macroscopic CNT assembly
materials, such as forests, gels, films, and fibers. In these assemblies,
structural deformation of CNTs, zipping and unzipping at CNT connection nodes,
strengthening and welding of the nodes, and sliding between CNTs or CNT bundles
are playing important roles in determining the viscoelasticity, and elasticity
as well. Towards the damping enhancement, strategies for micro-structure and
interface design are also discussed
Novel antibacterial and bioactive silicate glass nanoparticles for biomedical applications

In this work, the authors propose a new quick sol–gel procedure for bioglass
nanoparticles production containing 10% mol of silver (AgBGs). These new
AgBGs are characterized by Zeta potential analysis, scanning electron
microscopy with X-ray microanalysis (SEM/EDS), X-ray powder diffraction
(XRD), Fourier transform infrared spectroscopy (FTIR), and microbiological
tests to confirm their bioactive and antibacterial properties. SEM shows that
the average particle size is less than 200 nm and EDS confirms the successful
incorporation of Ag2O in the bioglass matrix. XRD confirms the amorphous
nature of the AgBGs and, after SBF immersion, reveals their bioactive
behavior with the presence of crystalline phase of calcium silicate and
phosphorus oxide, which are also detected by FTIR analysis. FTIR also
confirms the formation of typical siloxane bonds resulting from the
condensation of silicate glass. Lastly, it is found that the developed AgBGs
has an antibacterial effect against two different types of bacteria, thus
demonstrating their ability to reduce the bacterial infection within 16 h.The authors want to acknowledge the financial support from the Portuguese
Foundation for Science and Technology through the project BioSeaGlue with the reference
EXPL/CTM-BIO/0646/2013, and also the European program FEDER/COMPETE for the
financial support through project LA ICVS/3Bs-2014-2015.info:eu-repo/semantics/publishedVersio
Thin and flexible polymer photonic sensor foils for monitoring composite structures

Thin and flexible photonic sensor foils are proposed, fabricated and tested as a promising alternative for monitoring composite structures. Sensor foils are implemented using two different optical polymers and as such optimized for multi-axial sensing and embedding within composite materials respectively. It is first shown that those sensor foils allow multi-axial strain sensing by multiplexing a multitude of Bragg grating sensors in a rosette configuration. Secondly, those sensors can be realized in very thin foils (down to 50 μm) making them suitable for embedding in composite materials during their production. This was proven by visually inspecting and by testing the functionality of the embedded sensors. Finally, owing to their low Young’s modulus and flexibility, polymer sensor foils can be bent to small curvature radii and withstand large elongations. Herein, the sensors are bent down to a radius of 11 mm, and elongated by 1.4% without losing functionality
Systematic study of the growth of aligned arrays of alpha-Fe2O3 and Fe3O4 nanowires by a vapor-solid process

[[abstract]]Growth of aligned and uniform alpha-Fe2O3 nanowire (NW) arrays has been achieved by a vapor-solid process. The experimental conditions, such as type of substrate, local growth and geometrical environment, gas-flow rate, and growth temperature, under which the high density alpha-Fe2O3 NW arrays can be grown by a vapor-solid route via the tip-growth mechanism have been systematically investigated. The density of the alpha-Fe2O3 NWs can be enhanced by increasing the concentration of Ni atoms inside the alloy substrate. The synthesized temperature can be as low as 400 degrees C. Fe3O4 NWs can be produced by converting alpha-Fe2O3 NWs in a reducing atmosphere at 450 degrees C. The transformation of phase and structure have been observed by in situ transmission electron microscopy. The magnetic and field-emission properties of the NWs indicate their potential applications in nanodevices.[[fileno]]2020315010025[[department]]材料科學工程學
Studies of the temperature and frequency dependent impedance of an electroceramic functional oxide NTC thermistor

The charge transport mechanism and the macroscopic dielectric constant in polycrystalline device materials commonly exhibit several components such as electrode-sample interface, grain boundary and bulk contributions. In order to gain precise understanding of the functionality of polycrystalline electroceramic device materials it is essential to deconvolute these contributions. The paradigm of functional NTC thermistor ceramics based on thick film spinel manganates has been studied by temperature dependent alternating current impedance spectroscopy. Three typical relaxation phenomena were detected, which all showed a separated temperature dependence of resistivity consistent with thermally activated charge transport. The dominating grain boundary and the interface contributions exhibited distinctively different capacitance allowing clear identification. The composite nature of the dielectric properties in polycrystalline functional ceramics was emphasized, and impedance spectroscopy was shown to be a powerful tool to account for and model such behavior
The Large Electrochemical Capacitance of Microporous Doped Carbon Obtained by Using a Zeolite Template

9 pages, 7 figures.A novel microporous templated carbon material doped with nitrogen is synthesized by using a two-step nanocasting process using acrylonitrile (AN) and propylene as precursors, and Na-Y zeolite as a scaffold. Liquid-phase impregnation and in situ polymerization of the nitrogenated precursor inside the nanochannels of the inorganic scaffold, followed by gas-phase impregnation with propylene, enables pore-size control and functionality tuning of the resulting carbon material. The material thereby obtained has a narrow pore-size distribution (PSD), within the micropore range, and a large amount of heteroatoms (i.e., oxygen and nitrogen). In addition, the carbon material inherits the ordered structure of the inorganic host. Such features simultaneously present in the carbon result in it being ideal for use as an electrode in a supercapacitor. Although presenting a moderately developed specific surface area (S_BET = 1680 m2 g-1), the templated carbon material displays a large gravimetric capacitance (340 F g-1) in aqueous media because of the combined electrochemical activity of the heteroatoms and the accessible porosity. This material can operate at 1.2 V in an aqueous medium with good cycleability - beyond 10 000 cycles - and is extremely promising for use in the development of high-energy-density supercapacitors.The authors thank Norit for kindly supplying the activated carbon adsorbent.\ud
C.O.A. thanks MEC, Spain, for financial support (EX2004-0612). The kind help of R. Benoit for the XPS data is acknowledged.Peer reviewe
Lipoplex-loaded microbubbles for gene delivery: A Trojan horse controlled by ultrasound

Cationic poly(ethylene glycol)ylated (PEGylated) liposomes are one of the most important gene transfer reagents in non-viral gene therapy. However, the low transfection efficiencies of highly PEGylated lipoplexes currently hamper their clinical use. Recently, ultrasound has been used in combination with microbubbles to enhance the uptake of genes in different cell types. However, the gene transfer efficiency still remains low in these experiments. To overcome the limitations of both techniques, we present the attachment of PEGylated lipoplexes to microbubbles via biotin-avidin-biotin linkages. Exposure of these lipoplex-loaded microbubbles to ultrasound results in the release of unaltered lipoplexes. Furthermore, these lipoplex-loaded microbubbles exhibit much higher transfection efficiencies than "free" PEGylated lipoplexes or naked plasmid DNA (pDNA) when combined with microbubbles and ultrasound. Interestingly, the lipoplex-loaded microbubbles only transfect cells when exposed to ultrasound, which is promising for space- and time-controlled gene transfer. Finally, this novel Trojan-horse-like concept can also be exploited to achieve the ultrasound- triggered release of nanoparticles containing other therapeutic agents such as anticancer drugs
Nanodot-Enhanced High-Efficiency Pure-White Organic Light-Emitting Diodes with Mixed-Host Structures

[[abstract]]A relatively high-efficiency, fluorescent pure-white organic light-emitting diode was fabricated using a polysilicic acid (PSA) nanodot-embedded polymeric hole-transporting layer (HTL). The diode employed a mixed host in the single emissive layer, which comprised 0.5 wt % yellow 5,6,11,12-tetra-phenylnaphthacene doped in the mixed host of 50 % 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenylamino)styryl]naphthalene and 50 % N,N-bis-(1-naphthyl)-N,N-diphenyl-1,10-biphenyl-4-4-diamine. By incorporating 7 wt % 3 nm PSA nanodot into the HTL of poly(3,4-ethylene-dioxythiophene)-poly-(styrenesulfonate), the efficiency at 100 cd m-2 was increased from 13.5 lm W-1 (14.7 cd A-1; EQE: 7.2 %) to 17.1 lm W-1 (17.6 cd A-1; EQE: 8.3 %). The marked efficiency improvement may be attributed to the introduction of the PSA nanodot, leading to a better carrier-injection-balance.[[fileno]]2020306010044[[department]]材料科學工程學
Structure and properties of strontium-doped phosphate-based glasses

Owing to similarity in both ionic size and polarity, strontium (Sr2+) is known to behave in a comparable way to calcium (Ca2+), and its role in bone metabolism has been well documented as both anti-resorptive and bone forming. In this study, novel quaternary strontium-doped phosphate-based glasses, containing 1, 3 and 5 mol% SrO, were synthesized and characterized. P-31 magic angle spinning (MAS) nuclear magnetic resonance results showed that, as the Sr2+ content is increased in the glasses, there is a slight increase in disproportionation of Q(2) phosphorus environments into Q(1) and Q(3) environments. Moreover, shortening and strengthening of the phosphorus to bridging oxygen distance occurred as obtained from FTIR. The general broadening of the spectral features with Sr2+ content is most probably due to the increased variation of the phosphate cation bonding interactions caused by the introduction of the third cation. This increased disorder may be the cause of the increased degradation of the Sr-containing glasses relative to the Sr-free glass. As confirmed from elemental analysis, all Sr-containing glasses showed higher Na2O than expected and this also could be accounted for by the higher degradation of these glasses compared with Sr-free glasses. Measurements of surface free energy (SFE) showed that incorporation of strontium had no effect on SFE, and samples had relatively higher fractional polarity, which is not expected to promote high cell activity. From viability studies, however, the incorporation of Sr2+ showed better cellular response than Sr2+-free glasses, but still lower than the positive control. This unfavourable cellular response could be due to the high degradation nature of these glasses and not due to the presence of Sr2+
High-performance, low-operating-voltage organic field-effect transistors with low pinch-off voltages

Organic field-effect transistors suffer from ultra-high operating voltages in addition to their relative low mobility. A general approach to low-operating-voltage organic field-effect transistors (OFETs) using donor/acceptor buffer layers is demonstrated. P-type OFETs with acceptor molecule buffer layers show reduced operating voltages (from 60–100 V to 10–20 V), with mobility up to 0.19 cm2 V−1 s−1 and an on/off ratio of 3 × 106. The subthreshold slopes of the devices are greatly reduced from 5–12 V/decade to 1.68–3 V/decade. This favorable combination of properties means that such OFETs can be operated successfully at voltages below 20 V (|VDS| ≤ 20 V, |VGS| ≤ 20 V). This method also works for n-type semiconductors. The reduced operating voltage and low pinch-off voltage contribute to the improved ordering of the polycrystalline films, reduced grain boundary resistance, and steeper subthreshold slope
Surface engineered carboxymethylchitosan/poly(amidoamine) dendrimer nanoparticles for intracellular targeting

Novel highly branched biodegradable macromolecular systems have been developed by grafting carboxymethylchitosan
(CMCht) onto low generation poly(amidoamine) (PAMAM) dendrimers. Such structures organize into sphere-like nanoparticles
that are proposed to be used as carriers to deliver bioactive molecules aimed at controlling the behavior of stem cells,
namely their proliferation and differentiation. The nanoparticles did not exhibit significant cytotoxicity in the range of
concentrations below 1 mg mL"1, and fluorescent probe labeled nanoparticles were found to be internalized with highly
efficiency by both human osteoblast-like cells and rat bone marrow stromal cells, under fluorescence-activated cell sorting and
fluorescence microscopy analyses. Dexamethasone (Dex) has been incorporated into CMCht/PAMAM dendrimer nanoparticles
and release rates were determined by high performance liquid chromatography. Moreover, the biochemical data demonstrates
that the Dex-loaded CMCht/PAMAM dendrimer nanoparticles promote the osteogenic differentiation of rat bone marrow
stromal cells, in vitro. The nanoparticles exhibit interesting physicochemical and biological properties and have great potential to
be used in fundamental cell biology studies as well as in a variety of biomedical applications, including tissue engineering and
regenerative medicine
Fabrication and size-selective bioseparation of magnetic silica nanospheres with highly ordered periodic mesostructure

In this paper, we report a novel synthesis and selective bioseparation of the composite of Fe3O4 magnetic nanocrystals and highly ordered MCM-41 type periodic mesoporous silica nanospheres. Monodisperse superparamagnetic Fe3O4 nanocrystals were\ud
synthesized by thermal decomposition of iron stearate in diol in an autoclave at low temperature. The synthesized nanocrystals were encapsulated in mesoporous silica nanospheres through the packing and self-assembly of composite nanocrystal–surfactant micelles and surfactant/silica complex. Different from previous studies, the produced magnetic silica nanospheres (MSNs)\ud
possess not only uniform nanosize (90~140 nm) but also a highly ordered mesostructure. More importantly, the pore size and the saturation magnetization values can be controlled by using different alkyltrimethylammonium bromide surfactants and changing the amount of Fe3O4 magnetic nanocrystals encapsulated, respectively. Binary adsorption and desorption of proteins cytochrome c (cyt c) and bovine serum albumin (BSA) demonstrate that MSNs are an effective and highly selective adsorbent for proteins with different molecular sizes. Small particle size, high surface area, narrow pore size distribution, and straight pores of MSNs are responsible for the high selective adsorption capacity and fast adsorption rates. High magnetization values and superparamagnetic property of MSNs provide a convenient means to remove nanoparticles from solution and make the re-dispersion in solution quick following the withdrawal of an external magnetic fiel
A simple, one step approach to durable and robust superhydrophobic textiles

Superhydrophobic textile fabrics are prepared by a simple, one-step gas phase coating procedure by which a layer of polymethylsilsesquioxane nanofilaments is grown onto the individual textile fibers. A total of 11 textile fabrics made from natural and man made fibers are successfully coated and their superhydrophobic properties evaluated by the water shedding angle technique. A thorough investigation of the commercially relevant poly(ethylene terephthalate) fabric reveals an unparalleled long-term water resistance and stability of the superhydrophobic effect. Because of the special surface geometry generated by the nanoscopic, fibrous coating on the microscopic, fibrous textiles, the coated fabric remains completely dry even after two months of full immersion in water and stays superhydrophobic even after continuous rubbing with a skin simulating friction partner under significant load. Furthermore, important textile parameters such as tensile strength, color, and haptics are unaffected by the silicone nanofilament coating. For the first time, an in-depth characterization of the wetting properties, beyond simple contact angle measurements, as well as a thorough evaluation of the most important textile parameters is performed on a superhydrophobic fabric, which reveals a true potential for application
Electronic Transport Properties or Ensembles of Perylene-Substituted Poly-isocyanopeptide Arrays

Finlayson, C. E., Friend, R. H., Otten, M. B. J., Schwartz, E., Cornelissen, J. J. L. M., Notle, R. J. M., Rowan, A. E., Samori, P., Palermo, S., Palermo, V., Liscio, A., Peneva, K., M?llen, K., et al. (2008). Electronic Transport Properties of Ensembles of Perylene-Substituted Poly-isocyanopeptide Arrays. Advanced Functional Materials, 18 (24), pp. 3947-3955.The electronic transport properties of stacks of perylene-bis(dicarboximide) (PDI) chromophores, covalently fixed to the side arms of rigid, helical polyisocyanopeptides, are studied using thin-film transistors. In device architectures where the transistor channel lengths are somewhat greater than the average polymer chain length, carrier mobilities of order 10(-3) cm(2) V(-1) s(-1) at 350K are found, which are limited by inter-chain transport processes. The influence of pi-pi interactions on the material properties is studied by using PDIs with and without bulky substituents in the bay area. In order to attain a deeper understanding of both the electronic and the electronic-transport Properties of these systems, studies of self-assembly on surfaces are combined with electronic characterization using Kelvin probe force microscopy, and also a theoretical study of electronic coupling. The use of a rigid polymer backbone as a scaffold to achieve a full control Over the position and orientation of functional groups is of general applicability and interest in the design of building blocks for technologically important functional materials, as well as in more fundamental studies of chromophoric interactions.Peer reviewe
Size effect on properties of varistors made from zinc oxide nanoparticles through low temperature spark plasma sintering

Conditions for the elaboration of nanostructured varistors by spark plasma sintering (SPS) are investigated, using 8-nm zinc oxide nanoparticles synthesized following an organometallic approach. A binary system constituted of zinc oxide and bismuth oxide nanoparticles is used for this purpose. It is synthesized at roomtemperature in an organic solution through the hydrolysis of dicyclohexylzinc and bismuth acetate precursors. Sintering of this material is performed by SPS at various temperatures and dwell times. The determination of the microstructure and the chemical composition of the as-prepared ceramics are based on scanning electron microscopy and X-ray diffraction analysis. The nonlinear electrical characteristics are evidenced by current–voltage measurements. The breakdown voltage of these nanostructured varistors strongly depends on grain sizes. The results show that nanostructured varistors are obtained by SPS at sintering temperatures ranging from 550 to 600 8C
Reduced surfactant uptake in three dimensional assemblies of VO(x) nanotubes improves reversible Li(+) intercalation and charge capacity

The relationship between the nanoscale structure of vanadium pentoxide nanotubes and their ability to accommodate Li+ during intercalation/deintercalation is explored. The nanotubes are synthesized using two different precursors through a surfactant-assisted templating method, resulting in standalone VOx (vanadium oxide) nanotubes and also “nano-urchin”. Under highly reducing conditions, where the interlaminar uptake of primary alkylamines is maximized, standalone nanotubes exhibit near-perfect scrolled layers and long-range structural order even at the molecular level. Under less reducing conditions, the degree of amine uptake is reduced due to a lower density of V4+ sites and less V2O5 is functionalized with adsorbed alkylammonium cations. This is typical of the nano-urchin structure. High-resolution TEM studies revealed the unique observation of nanometer-scale nanocrystals of pristine unreacted V2O5 throughout the length of the nanotubes in the nano-urchin. Electrochemical intercalation studies revealed that the very well ordered xerogel-based nanotubes exhibit similar specific capacities (235 mA h g −1) to Na+-exchange nanorolls of VOx (200 mA h g −1). By comparison, the theoretical maximum value is reported to be 240 mA h g −1. The VOTPP-based nanotubes of the nano-urchin 3D assemblies, however, exhibit useful charge capacities exceeding 437 mA h g −1, which is a considerable advance for VOx based nanomaterials and one of the highest known capacities for Li+ intercalated laminar vanadates
Lithium-catalyzed dehydrogenation of ammonia borane within mesoporous carbon framework for chemical hydrogen storage

Ammonia borane (AB) has attracted tremendous interest for on-board hydrogen storage due to its low molecular weight and high gravimetric hydrogen capacity below a moderate temperature. However, the slow kinetics, irreversibility, and formation of volatile materials (trace borazine and ammonia) limit its practical application. In this paper, a new catalytic strategy involved lithium (Li) catalysis and nanostructure confinement in mesoporous carbon (CMK-3) for the thermal decomposition of AB is developed. AB loaded on the 5% Li/CMK-3 framework releases 7 wt % of hydrogen at a very low temperature (around 60 °C) and entirely suppresses borazine and ammonia emissions that are harmful for proton exchange membrane fuel cells. The possible mechanism for enhanced hydrogen release via catalyzed thermal decomposition of AB is discussed
Electric field Assisted Nanostucturing of a Mott Insulator

Accepted for Advanced Functional Materials Published as : Adv Funct Mat Vol 19 p 2800 (2009)International audienceWe report the first experimental evidence for a strong electromechanical coupling in the Mott insulator GaTa4Se8 allowing a highly reproducible nano-writing with a Scanning Tunneling Microscope (STM). The local electric field across the STM junction is observed to have a threshold value above which the clean (100) surface of GaTa4Se8 becomes mechanically instable: At voltage biases V > 1.1V the surface suddenly inflates and comes in contact with the STM tip, resulting in nanometer size craters. The formed pattern can be indestructibly “read” by STM at lower voltage bias, thus allowing a 5 Tdots/inch2 dense writing/reading at room temperature. The discovery of the electromechanical coupling in GaTa4Se8 might give new clues in the understanding of the Electric Pulse Induced Resistive Switching recently observed in this stoechiometric Mott insulator