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Nickel–Cobalt hydroxide microspheres are electrodepositioned on the films of NiCo2O4 nanowires grown on the current collector through a facile approach and the hierarchical structures are then investigated as an electrode material for high-performance supercapacitors. Owing to the superior electrical conductivity of NiCo2O4 nanowires, the porous structure of the (Ni–Co)(OH)2 microspheres and the synergic effect of the multi-components, the electrode can deliver a high areal capacitance of 6 F cm−2 and a corresponding specific capacitance of 1132 F g−1 at a current density of 2 mA cm−2, as well as a good rate capability (61.8% capacitance retention from 2 mA cm−2 to 50 mA cm−2), and excellent cycling stability (90% capacitance retention after 2000 cycles). The results suggest that our research opens up the possibility for the fabrication of high-performance energy-storage devices of binder-free electrodes.

Silicone rubber filled with thermally conductive alumina is fabricated as a class of thermal interface materials in this work. The thermal conductivity of the prepared alumina/silicone rubber composite is measured as a function of alumina loading. The effects of alumina filler with different phases and morphologies on the thermal conductivity of the composite are investigated by comparative method. When the filler loading is low, the composite filled with porous irregular-shaped α-alumina exhibits a higher thermal conductivity than that filled with γ-Al2O3 and spherical α-Al2O3. In order to achieve a high loading, spherical α-Al2O3 has the most pronounced effect due to its intrinsic high thermal conductivity and unique morphology for homogeneous dispersion in the polymer matrix, which is superior to irregular-shaped α- and γ-Al2O3. Our results demonstrate that the composite filled with spherical alumina by the mass concentration of 82 % has six times thermal conductivity higher than pure silicone rubber. Thermogravimetric analysis studies exhibit that the thermal stability of the composite distinctly increases with filler loadings. The obtained data were compared with theoretical equations in the literatures that are used to predict the properties of two-phase mixtures.

Pure NiAl-layered double hydroxides (LDHs) and graphene oxide (GO)/NiAl-LDHs composites are both fabricated by refluxing solution with the assistance of microwave irradiation within 2 hours. The structural characterization and morphological observation of the composites suggest that small NiAl-LDHs crystals are in situ grown on the surface of GO nanosheets, preventing the compact stacking of GO as an intercalated spacer. The electrochemical performances of pure LDHs and GO/NiAl-LDHs composites with different content of GO are investigated and compared. The GO/NiAl-LDHs composite containing 23 wt% GO exhibits a higher specific capacitance of 1630 F g−1 at 1 A g−1 in 6 M KOH solution and more stable rate capability than others. When GO is substituted by microwave reduced graphene oxide (rGO) or the GO in the GO/NiAl-LDHs composite is thermally reduced at a rational temperature, rGO/NiAl-LDHs composites are obtained with enhanced electrochemical behavior in rate capability and cycle life. Critical comparisons indicate that rGO/NiAl-LDHs composite prepared by thermal reducing GO/NiAl-LDHs has better cycling performance and rate capability than the counterpart directly prepared with rGO.

Pure hexagonally layered α-Co(OH) 2 powder is prepared in large quantity by precipitation method under mild conditions. Subsequently, anion-exchange reaction and aging treatment in alkaline medium are performed to find their influence on the microstructure and supercapacitive properties of α-Co(OH) 2 . Various inorganic anions are successfully intercalated into the interlayer gallery of α-Co(OH) 2 with the morphology and structure reserved. While the α-Co(OH) 2 transforms into other cobalt compounds by aging treatment 1 Mol L −1 KOH solution at room temperature. The effects of anion-exchange on the supercapacitive properties are evaluated by cyclic voltammetry and galvanostatic charge–discharge tests. The α-Co(OH) 2 exhibits a high specific capacitance, good rate capability and improved stability after intercalation with nitrate and sulfate. The morphology and structure of α-Co(OH) 2 after 2000 continuous charge–discharge tests in 1 Mol L −1 KOH electrolyte are also well maintained, indicating its excellent stability in charge–discharge tests. In contrary, the phase transitions from α-Co(OH) 2 to β-form and other cobalt phases lead to a dramatic decrease in the specific capacitance, from 763.4 F g −1 to 25.9 F g −1 .

Hybrid materials of carbon nanotubes (CNTs) coated with nickel-cobalt (Ni-Co) oxide nanoparticles were synthesized using electroless plating. Transmission electron microscopy images showed that Ni-Co oxide nanoparticles were dispersively distributed on the external surface of CNTs. The composites of Ni-Co oxides modified CNTs were used as additives of activated carbon to improve the electrochemical performance of the electrode materials for supercapacitors. The electrochemical properties of the supercapacitors were investigated by galvanostatic charge–discharge, cyclic voltammetry, and alternating current impedance techniques. The maximum specific capacitance reached 215 F g $^{-1}$ , approximately 23% higher than that without addition of the CNT-based composite, while the resistance of the electrode was also reduced by addition of the composite. The results revealed that the supercapacitor had an excellent charge–discharge cycle behavior and electrochemical stability after 1200 continuous cycles. The improved performance of the supercapacitor can be attributed to the modified structure and high electrical conductivity of the electrode materials due to the addition of the hybrid nanocomposite, which is promising for energy storage applications.

One dimensional hierarchically hollow SnO2/α-Fe2O3 core–shell nanofibers were synthesized by using electrospun SnO2 hollow nanofibers as core followed by the hydrothermal growth and calcination of α-FeOOH nanorods on the outer surface of SnO2 nanofibers. The control experiments indicated that glacial acetic acid introduced in the hydrothermal solution could adjust the nucleation site and density of α-FeOOH nanorods as well as prevent the formation of urchin-like α-FeOOH byproduct. The growth process of α-FeOOH nanorods on SnO2 hollow nanofibers was also investigated. The hierarchical SnO2/α-Fe2O3 hollow nanofibers were then fabricated as gas sensors for the investigation of gas sensing applications. By comparison of sensing properties, the response values of the sensors fabricated with hierarchical SnO2/α-Fe2O3 core–shell nanofibers toward 100 ppm acetone and ethanol could reach to be 30.363 and 20.370, respectively, exhibiting much better performance than those using urchin-like α-Fe2O3 nanostructures and pure SnO2 nanofibers. Meanwhile, the sensors based on hierarchical SnO2/α-Fe2O3 nanofibers also had shorter response and recovery times than those of α-Fe2O3 nanostructures. The synergetic effect of the composite of α-Fe2O3 and SnO2 together with unique hollow core–shell architectures are main contribution for the enhanced gas sensing properties.

Additional symmetry is an important kind of symmetries depending explicitly on the time and space variables, which can be expressed through Sato–Bäcklund transformations. In this paper, we construct Sato–Bäcklund transformations of the modified KP hierarchy and its constrained cases. Then the string equations of the [Formula: see text]-reduced modified KP hierarchy are established by requiring the system independent on some additional symmetry flows, which are expressed by the Lax operator [Formula: see text] and the Orlov–Shulman’s operator [Formula: see text]. At last, we obtain the negative Virasoro constraint on the two tau functions of the 2-reduced modified KP hierarchy satisfying the string equations.

In this work, pure and Ni-doped SnO2 hollow nanofibers with porous structures were fabricated through combination of electrospinning technique and calcination procedure. The hollow SnO2 nanofibers were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), X-ray photoelectron spectroscopy (XPS) and their gas sensing properties for acetone were also investigated. A high heating rate in calcination process would lead to the formation of hollow SnO2 nanofibers with a tube-like structure. Hollow Ni-doped SnO2 nanofibers could be prepared by adjusting Ni2+ concentration in the precursor solution using a facile process with appropriate thermal treatment. Comparative gas sensing properties revealed that Ni-doped SnO2 hollow nanofibers exhibited a much higher response in detecting acetone vapor than both pure SnO2 hollow nanofibers and Ni-doped SnO2 solid nanofibers at the same temperature. The excellent sensing performances of Ni-doped SnO2 hollow nanofibers were ascribed to its hollow-core structure and Ni doping.

Three-dimensional network of cobalt and aluminum layered double hydroxide (LDH) nanosheets was synthesized on nickel foam by a simple hydrothermal method. The CoAl-LDH nonosheets were subsequently coated by ion sputtering with thin layers of Pt films to facilitate fast electron transport between current collector and the CoAl-LDH active materials. The optimal thickness of the Pt film acquiring the best performance was identified by applying various sputtering time in controlled experiments. The supercapacitor built by the CoAl-LDH nanosheets coated with Pt film sputtered for 5 min has a high specific capacitance (734.4 F g −1 at 3 A g −1 ), excellent rate capability as well as cycling stability. Moreover, it showed a long life of 77% retention after 6000 cycles and its general morphology was preserved after the test. The synergetic affect of conductive layer of Pt films and CoAl-LDH on the improvement of electrochemical properties was discussed and this would provide a useful clue in designing novel and effective electrode materials for supercapacitors.

Fe 3 O 4 /reduced graphene oxide (rGO) composites were prepared by a two-step method: solution precipitation followed by hydrogen reducing. The mass ratio of Fe 3 O 4 to rGO in the composites could be carefully controlled in the first step. The structure and morphology of Fe 3 O 4 /rGO composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The electrochemical properties of the composites as electrode of supercapacitors were investigated using cyclic voltammetry and galvanostatic charge–discharge tests. It was found that the mass ratio of Fe 3 O 4 to rGO had great effects on the crystal size of Fe 3 O 4 , specific surface areas and pore volume, as well as the specific capacitance of the composites. The capacitance of the composite was higher than that of any individual component due to the synergetic effect between Fe 3 O 4 and rGO. The composite exhibited an excellent cyclic stability and could maintain the initial capacity over 1000 cycles without any decay. This report provides useful clues in design and synthesis graphene-based composites for the applications as energy materials.

In this paper, under the constraints of the BKP(CKP) hierarchy, a crucial observa- tion is that the odd dynamical variable u2k+1 can be explicitly expressed by the even dynamical variable u2k in the Lax operator L through a new operator B. Using operator B, the essential differences between the BKP hierarchy and the CKP hierarchy are given by the flow equations and the recursion operators under the (2n+1)-reduction. The formal formulas of the recursion operators for the BKP and CKP hierarchy under (2n+1)-reduction are given. To illustrate this method, the two recursion operators are constructed explicitly for the 3-reduction of the BKP and CKP hierarchies. The t7 flows of u2 are generated from t1 flows by the above recursion operators, which are consistent with the corresponding flows generated by the flow equations under 3-reduction.

Undoped and Al-doped ZnO nanofibers were synthesized via a simple electrospinning method, and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman scattering and photoluminescence (PL) spectroscopy. The ethanol sensing properties of the sensor based on the nanofibers were also investigated. The results show that the sensor fabricated from Al-doped ZnO nanofibers exhibits better gas sensing performance than that fabricated from the undoped ZnO nanofibers, and the gas sensing mechanism is discussed.

Electron tomography based on Z-contrast scanning transmission electron microscopy (STEM) can be applied to study 3D morphology of nanomaterials at high resolution, that is, 1 nm in all three spatial dimensions, to provide comprehensive insights into the structure of nanomaterials and their interfaces. Here, we report the 3D characterization of Au-catalyzed Ge and Si nanowires using a full-space tilting holder to address the “missing wedge” problem in STEM electron tomography. Electron tomography specimens were prepared by a novel two-step sample preparation process to minimize surface damage induced by focused ion beam (FIB) milling. The quality of specimen preparation protocol is demonstrated by the clear visibility of {112} facets in the reconstructed volume, and 3D morphology of Au nanoparticles on the nanowire surface. The 3D distribution of the Au nanoparticles on the coated Ge nanowires is also established. The integrated combination of innovative specimen preparation and full-tilt tomography repres...

A variety of carbon materials varying from 0D to 2D, i.e. 0D nanoparticles, 1D carbon nanotubes (CNTs) and 2D reduced graphene oxide (rGO) are selected to in situ combine with Ni–Mn layered double hydroxide (LDH) to prepare electrode materials for supercapacitors. Through a simple solution method, hierarchical Ni–Mn LDH/carbon composites can be easily fabricated. A comparative study is carried out on the sandwich-like LDH/rGO, flower-like LDH/carbon black, turbostratic-structured LDH/CNTs and ternary LDH/CNTs/rGO for their structure, morphology, porous properties and electrochemical performances. The results show that the ternary Ni–Mn LDH/CNTs/rGO composite yields the highest specific capacitance of 1268 F g−1 in 2 M KOH electrolyte and a long lifespan, exhibiting great potential for supercapacitor applications. Meanwhile, investigation on the influence of the cation species of MOH (M = Li+, Na+ or K+) and the alkali concentration of the KOH electrolyte illustrates that increasing the concentration of the KOH electrolyte can benefit the capacitive performance of the electrode and that NaOH shows great advantages as an electrolyte for the Ni–Mn LDH/CNTs/rGO electrode due to its high capacitance and small resistance.

There are economic and environmental advantages by replacing Li with Na in energy storage. However, sluggishness in the charge/discharge reaction and low capacity are among the major obstacles to development of high-power sodium-ion batteries. Among the electrode materials recently developed for sodium-ion batteries, selenium shows considerable promise because of its high capacity and good cycling ability. Herein, we have investigated the mechanism and kinetics of both sodiation and lithiation reactions with selenium nanotubes, using in situ transmission electron microscopy. Sodiation of a selenium nanotube exhibits a three-step reaction mechanism: (1) the selenium single crystal transforms into an amorphous phase Na0.5Se; (2) the Na0.5Se amorphous phase crystallizes to form a polycrystalline Na2Se2 phase; and (3) Na2Se2 transforms into the Na2Se phase. Under similar conditions, the lithiation of Se exhibits a one-step reaction mechanism, with phase transformation from single-crystalline Se to a Li2Se. Intriguingly, sodiation kinetics is generally about 4-5 times faster than that of lithiation, and the kinetics during the different stages of sodiation is different. Na-based intermediate phases are found to have improved electronic and ionic conductivity compared to those of Li compounds by first-principles density functional theory calculations.

A microwave-assisted reflux method was used to rapidly synthesize CoAl-layered double hydroxide (CoAl-LDH)/graphene oxide composite. In the synthetic procedure, graphite oxide (GO) was exfoliated to graphene oxide nanosheets in company with the in situ growth of CoAl-LDH. The as-prepared products showed lamellar structures. The aggregation of LDH was effectively prevented by the presence of graphene oxide nanosheets. Electrochemical performances were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests. All the composites had higher rate capability than pure CoAl-LDH, maintaining about 80% of discharge capacitance when the current density increased from 1 A g−1 to 20 A g−1. A maximum specific capacitance of 772 F g−1 was obtained at 1 A g−1 in 6 M KOH solution for the composite containing 12.9% GO. Moreover, the composite exhibited excellent long cycle life with about 73% specific capacitance retained at 6 A g−1 after 10,000 cycles.

Magnetic photocatalysts composed of titania catalyst and magnetic support are of great interest due to their easy recovery and recyclability by magnetic separation. By using layer-by-layer chemical technique, a core–shell structure of Fe3O4/SiO2/TiO2 composite was prepared by coating magnetite core particles with silica and photoactive titania. An amorphous silica shell was coated on magnetite nanoparticles firstly to form SiO2/TiO2 composite. In the next step of synthesis, we found that the polyacrylic acid treatment on silica surface played an important role in the coating of the anatase nanoparticles: no any anatase nanoparticles could be attached to the silica surface without the polyacrylic acid treatment. The structure and morphology of the as-prepared composites were characterized by X-ray diffraction, infrared spectroscopic analysis and transmission electron microscopy. Experimental results proved that the treatment of silica surface with polyacrylic acid contributed to the formation of covalent bond between titania nanocrystals and silica. The as-prepared photocatalyst presented good photocatalytic activities in the degradation of rhodamine B under UV illusion, while it could be easily separated by external magnetic field.

Summary Objective: The pathogenesis of IgA nephropathy (IgAN) is still unknown. Combination therapy with angiotensin-converting enzyme inhibitors (ACEIs) plus angiotensin receptor blockers (ARBs) might provide more benefits to IgAN patients. We conducted a systematic review to assess the efficacy of combination therapy for IgAN. Methods: The MEDLINE, EMBASE, the Cochrane Library and article reference lists were searched for randomised clinical trials (RCTs) which involved combination therapy ACEI plus ARB in only one arm. A meta-analysis was performed on the outcomes of proteinuria and renal function in IgAN patients. Results: Six RCTs involving 109 patients were included in the review. Combined treatment with ACEI plus ARB was more effective than with ACEI/ARB alone for reducing daily proteinuria. This did not translate into an improvement in GFR. Patients receiving ACEI plus ARB therapy did not have an increased risk of hyperkalemia. Conclusions: The current cumulative evidence suggests that combination therapy ACEI plus ARB may provide more benefits to IgAN patients for reducing daily proteinuria. Long-term effects of these agents on renal outcomes, and safety need to be established.

Hybrid structures of carbon nanofibers (CNFs) and activated carbon (AC) have been fabricated using natural potato starch as the substrate for in situ growth of the CNFs. Iron nitrate was used as both the activation agent and the catalyst precursor. The AC was derived from potato starch and the CNFs grew from the surface of AC. The hybrid structure has a large specific surface area (approximately 1930 m 2 g −1 ) and exhibits excellent electrochemical properties as supercapacitor for electrode materials. Its capacitance reaches a peak value of 268 F g −1 with an excellent cyclical ability, which is attributed to the unique hybrid structure, large specific surface area, and the high electron conductivity of CNFs grown in situ with AC. These low cost, eco-friendly CNF/AC hybrid structures are promising for energy storage.

Strong absorption, low density, and thin matching thickness are important parameters for electromagnetic (EM) wave absorbers. In this study, we prepared novel porous magnetic nanocomposites using corncob powders as template. The presence of corncob will significantly decrease the bulk density of samples from more than 4.0 to about 0.55 g cm −3 . The porous structures remarkably decreased the permittivity ( e ) and permeability ( μ ) and enhanced the impendence matching between the absorber and air. The porous magnetic nanocomposites exhibit enhanced absorption for EM waves at thin matching thickness. The optimum thickness is only 1.0–1.4 mm, with bandwidth of RL X -band and the whole K u -band. The areal density of magnetic absorbers at this study is only about 0.7–1.0 kg m −2 at thickness of 1.0–1.4 mm, much lower than the reported values of other magnetic absorbers. Due to the strong absorption at low density and thin matching thickness, the porous magnetic nanocomposites prepared using corncob powders as template are promising light-weight EM wave absorbers.

Low density and thin thickness are essential for electromagnetic (EM) wave absorbers. In this study, we fabricated a novel micro-tubular iron nanocomposite (MTIC) that composed of carbon microtubes and monodisperse iron nanoparticles (NPs). The bulk density of MTIC is only 0.35±0.04 g cm −3 due to its micro-tubular structure. The presence of iron NPs increased the magnetic loss significantly and therefore enhanced the reflection loss (RL) of MTIC/paraffin composite. The optimum thickness for the composite is 1.5–1.8 mm, with maximum bandwidth of 7.6 GHz for RL

The Ni/Carbon nanotubes (CNTs) composites for supercapacitor electrode have been synthesized by electroless deposition method. The morphology and structure of Ni/CNTs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The nano-size Ni particles coated the surface of carbon nanotubes. Electrochemical performances of the synthesized composites were investigated by cyclic voltammetry and galvanostatic charge/discharge measurement. The specific capacitance of prepared electrode is up to 281 F/g, which is much higher than acetylene black electrode and pure carbon nanotubes electrode, indicating an effective path for increasing specific capacitance of carbon materials for the appplication of supercapacitors.

Magnetite nanocrystals are deposited on carbon nanotubes by a reflux method in diethylene glycol. The morphological characterization proves that magnetite nanocrystals are decorated on the external surfaces of carbon nanotubes. The crystal size of magnetite nanocrystals can be readily tuned by adjusting the content of sodium acetate, but the content of sodium acetate has little effect on the amount of magnetite. The magnetite/carbon nanotubes composites exhibit an initial capacity as high as 840 mAh g−1 and an excellent cycling performance for lithium storage. The reversible capacity, as high as 390 mAh g−1, can be maintained after 75 charge/discharge cycles. The research has potential implications for the application of magnetite/carbon nanotubes composites as anode materials of lithium ion batteries.

We report a one-step synthesis of a nanocomposite of goethite (α-FeOOH) nanorods and reduced graphene oxide (RGO) using a solution method in which ferrous cations serve as a reducing agent of graphite oxide (GO) to graphene and a precursor to grow goethite nanorods. As-prepared goethite nanorods have an average length of 200 nm and a diameter of 30 nm and are densely attached on both sides of the RGO sheets. The electrochemical properties of the nanocomposite were characterized by cyclic voltammetry (CV) and chronopotentiometry (CP) charge–discharge tests. The results showed that goethite/RGO composites have a high electrochemical capacitance of 165.5 F g −1 with an excellent recycling capability making the material promising for electrochemical capacitors.

Mesoporous cobalt oxide micro-flowers have been synthesized by a simple, surfactant-free method without employing any templates. In this method, cobalt hydroxide micro-flowers were initially prepared in a solution medium. Subsequently, they were applied as a precursor of cobalt oxide by heat treatment, to transform into porous micro-flowers. The morphology of cobalt oxide retained that of its precursor. Experimental analysis confirmed that calcination temperature had great influence on the pore structure and crystal size. The average size of cobalt oxide crystals increased with increasing calcination temperature. Nitrogen adsorption/desorption data showed that the pore size increased and the BET surface area decreased with the gradual increase of calcination temperature. The electrochemical properties of the cobalt oxide were investigated by cyclic voltammetry measurements.

Two-dimensional plate-like Fe(3)O(4) nanocrystals were synthesized by a facile method using ultrasonic irradiation in aqueous solution at low temperature without protection from oxygen. The crystals were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier Transform infrared spectroscopy. The products subjected to ultrasound showed a two-dimensional morphology. The results obtained indicate that the morphologies of the magnetite crystals depend more on the ultrasonic irradiation than on the growth temperature. The thickness and width of the crystals increased with increasing temperature of the reaction medium. In addition, the magnetic hysteresis loop of the magnetite nanoplates was obtained at room temperature.

Flower-like Co 3 O 4 hierarchical microspheres composed of self-assembled porous nanoplates have been prepared by a two-step method without employing templates. The first step involves the synthesis of flower-like Co(OH) 2 microspheres by a solution route at low temperatures. The second step includes the calcination of the as-prepared Co(OH) 2 microspheres at 200 °C for 1 h, causing their decomposition to form porous Co 3 O 4 microspheres without destruction of their original morphology. The samples were characterized by scanning electron microscope, transmission electron microscope, X-ray diffractormeter and Fourier transform infrared spectroscope. Some experimental factors including solution temperature and surfactant on the morphologies of the final products have been investigated. The magnetic properties of Co 3 O 4 microspheres were also investigated.

Two-dimensional plate-like Fe3O4 nanocrystals and nanoparticles could be synthesized by a simple one-step sonochemical method through ultrasonic irradiation in reverse co-precipitation solution at low temperature. This technique provided a facile and rapid way to prepare Fe3O4nanocrystals with different morphology and size. Magnetite nanoplates were synthesized with only ferrous salt adding into alkali solution, and adding ferric ions with low molar ratio in the metal salts solution would lead to the formation of very small magnetite nanoparticles (∼10 nm). The size of as-prepared magnetite nanoparticles increased with increasing reaction temperature and showed narrow size distribution, the standard deviation less than 2 nm. This investigation indicated that ferric ions had significant influence on the morphology of Fe3O4 nanocrystals. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Large-scale two-dimensional ZnO nanocrystal films on aluminum substrate were fabricated by a one-step hydrothermal method under mild conditions, where all the ZnO nanocrystals had a lamellar structure generally perpendicular to the substrates and formed network-like porous configurations. The morphologies of the films were dependent on both the reaction temperature and concentration of zinc. The wettability of the ZnO films was assessed by measuring the water contact angle without any surface functionalisation. The porous structures of the as-prepared films could effectively enhance its hydrophobicity and the water contact angle ranged from 40° to 135° depending on the surface morphology and the arrangement of ZnO planes, indicating a simple and promising route to make aluminum surface waterproof and even self-cleaning. The hydrophobic ZnO surface could be switched to hydrophilic state by UV irradiation. A grande echelle films nanocristaux de ZnO a deux dimensions sur substrat d'aluminium ont ete fabriquees par un procede hydrothermal en une etape dans des conditions douces, ou tous les nanocristaux de ZnO ont une structure lamellaire generalement perpendiculaire aux substrats et forme des configurations poreux de type reseau. Les morphologies des films dependent a la fois la temperature de reaction et la concentration de zinc. La mouillabilite des films de ZnO a ete evaluee en mesurant l'angle de contact de l'eau sans la fonctionnalisation de surface. Les structures poreuses des films pourrait effectivement augmenter l'hydrophobie et l'angle de contact de l'eau variait de 40 a 135° en fonction de la morphologie de surface et l'arrangement des plans de ZnO, indiquant une route simple et promettant de faire surface en aluminium impermeable et meme auto-nettoyant. La surface hydrophobe de ZnO pouvaient etre transformes en etat hydrophile par irradiation UV.

In this paper, we derive a general formula of the flow equtions for the Harry—Dym hierarchy. And three applications in n-reduction, (2 + 1)-dimensional generalization, and Kupershmidt reduction, are considered.

In this paper, we investigate the squared eigenfunction symmetries under the Miura and reverse-Miura transformations, between the discrete KP and modified discrete KP hierarchies, in unconstrained and constrained cases. What is more, the squared eigenfunction symmetries for the constrained discrete KP and constrained modified discrete KP hierarchies are constructed by imposing the additional conditions on the generating eigenfunctions of the corresponding symmetries.

The research on supercapacitors has been attractive due to their large power density, fast charge/discharge speed and long lifespan. The electrode materials for supercapacitors are thus intensively investigated to improve the electrochemical performances. Various transition metal layered double hydroxides (LDHs) with a hydrotalcite-like structure have been developed to be promising electrode materials. Earth-abundant metal hydroxides are very suitable electrode materials due to the low cost and high specific capacity. This is a review paper on NiMn LDHs for supercapacitor application. We focus particularly on the recent published papers using NiMn LDHs as electrode materials for supercapacitors. The preparation methods for NiMn LDHs are introduced first. Then, the structural design and chemical modification of NiMn LDH materials, as well as the composites and films derived from NiMn LDHs are discussed. These approaches are proven to be effective to enhance the performance of supercapacitor. Finally, the reports related to NiMn LDH-based asymmetric supercapacitors are summarized. A brief discussion of the future development of NiMn LDHs is also provided.

CuO/MWCNT nanocomposite is prepared by a simple precipitation method. The MWCNTs are incorporated into the leaf-like CuO nanoplates and build up a network to connect the CuO nanoleaves. The as-prepared CuO/MWCNT exhibits superior reversible Li-ion storage, the capacity maintains 627 mAh g−1 at 60 mA g−1 even after 50 cycles. The improved capability is ascribed to the MWCNT network in the composite, which improves the electrical contact of CuO/CuO and CuO/current collector, facilitates the charge transfer on CuO/electrolyte interfaces, and compensates the volume change of CuO during cycling. Keywords: Copper oxide, Carbon nanotube, Anode, Lithium ion battery

Nanocomposites composed of carbon nanotubes (CNTs) and magnetite (Fe 3 O 4 ) nanoparticles were fabricated by using ethylene glycol as reductant at 160 °C. The composites were subsequently annealed under different temperatures in an inert atmosphere. The products were characterized by transmission electron microscopy (TEM), high resolution TEM, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the Fe 3 O 4 transformed from amorphous phase into single crystalline nanoparticles after annealing and that the annealing temperature played a crucial role in controlling the size and the size distribution of Fe 3 O 4 nanoparticles. The average size of Fe 3 O 4 nanoparticles increased with increasing annealing temperature. Meanwhile, the size distribution of nanoparticles became wide with the increase of temperature. It was caused by the gradual decomposition of oleate groups attached on the CNT surface. Magnetic hysteresis loop measurements revealed that crystalline Fe 3 O 4 /CNTs displayed superparamagnetic behavior under room temperature.

In this paper, we mainly study the gauge transformations of the constrained q-deformed Kadomtsev–Petviashvili (q-KP) hierarchy. Different from the usual case, we have to consider the additional constraints on the Lax operator of the constrained q-deformed KP hierarchy, since the form of the Lax operator must be kept when constructing the gauge transformations. For this reason, the selections of generating functions in elementary gauge transformation operators [Formula: see text] and [Formula: see text] must be very special, which are from the constraints in the Lax operator. At last, we consider the successive applications of n-step of [Formula: see text] and k-step of [Formula: see text] gauge transformations.

A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere. The rice husk substrate consists of porous activated carbon and silica, where spinel ferrite particles with average diameter of 59 nm are distributed. The surface area of the composite is greater than 170 m2 g−1 and the bulk density is less than 0.6 g cm−3. Inert atmosphere is indispensable for the synthesis of pure ferrite composites, while different preparation temperatures of above 600 °C result in composites with similar structures and morphologies. Due to the presence of ferrite particles, this novel composite shows enhanced adsorption ability for acid orange II.

Dense YMnO3 multiferroic ceramics were prepared by a novel technique of in situ SPS (spark plasma sintering) combined with annealing, and both the dielectric and magnetic characterizations were conducted. Compared with the conventional ceramic process, the synthesis process was greatly simplified, and dense YMnO3 ceramics with uniform microstructures were achieved at a relatively low temperature in very short time. Dielectric characteristics of dense YMnO3 ceramics were well evaluated over broad temperature and frequency ranges. An obvious dielectric relaxation was observed in the low temperature range and a dielectric step was detected in the higher temperature range. Systemic magnetism studies of the present YMnO3 ceramics indicated a weak ferromagnetic characteristic in the temperature lower than the antiferromagnetic transition temperature (TN).

Adsorbent/ferrite composites can adsorb and degrade organics in the organic wastewater treatment. In this study, a rice hull/MnFe 2 O 4 composite (RHM) was prepared via calcination under nitrogen atmosphere and was used to treat organic wastewater with the assistance of microwave radiation. Rice hull was pyrolysed to a porous substrate that consisted of silica and activated carbon under high temperature. Monodisperse spinel MnFe 2 O 4 nanoparticles whose mean diameter is around 59 nm are distributed on the substrate. With the assistance of microwave radiation, RHM was motivated to a hotspot of adsorption and catalysis which could remove more than 70% COD of wastewater within 6 min. The maximum COD removal was 73.5% when the concentration of RHM was 15 mg mL −1 and the irradiation time of microwave radiation was 6 min. Although the BET surface area and iodine value of RHM are half of rice hull ash (RHA), the COD removal of RHM is 7–20% higher than that of RHA. It is attributed to the presence of MnFe 2 O 4 , which enhances the catalytic activity of RHM. RHM can be regenerated via water washing. However, the surface area and the maximum COD removal of RHM decrease for each regeneration cycle. With the advantages of low cost and rapid processing, this novel rice hull/MnFe 2 O 4 composite could gain promising application in wastewater treating-agent.

A high-yield of carbon nanotubes filled with β-Sn nanowires has been produced by the thermal pyrolysis of acetylene over SnO 2 catalysts. Electron beam irradiation (EBI) induced melting and flow of Sn in the nanotubes and this could be controlled by changing the electron beam current density. The mass flow rate of the Sn ranged from 0.9 to 8.2 fg/s. The melting of the nanowires is a result of the temperature rise caused by the EBI. Many factors, including temperature variation, charging, and EBI induced deformation of the carbon shells, contribute to the flow of Sn.

Bundle-like multi-walled carbon nanotubes (MWNTs) were melting-mixed with high-density polyethylene (HDPE). MWNTs are distributed in the matrix mostly isolated. Agglomerates are observed at higher concentrations. The electric conductivity of the composites follows the theory of a percolation system, and the charge transport shows different models. The temperature dependence of the electrical conductivity for the composites shows that both positive (PTC) and negative (NTC) temperature coefficients appear near the melting temperature of matrix. The NTC behaviors within the temperature range below the melting point depend on the MWNTs concentration and the NTC intensity increases with the increasing MWNTs concentration.

ZnO nanoplate thin films have been synthesized by a one-step solution technique in a surfactant-free system. The structure and morphology of the fabricated ZnO nanoplates were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. These network-like nanoplates were dispersed quasi-vertically and homogenously on aluminum substrates. The size of ZnO nanoplate was depended on the reaction temperature. Increasing the reaction temperature would result in much thicker and wider ZnO nanoplates. The density of ZnO nanoplates was determined by zinc concentration. Under high temperature, these ZnO nanoplates tended to recrystallization and its density would decrease. Photoluminescence properties of the as-prepared and annealed ZnO nanoplate films were studied in this work.

Multi-walled carbon nanotubes were decorated with nickel cations after nitric acid oxidization and the resultant product was calcined in an inert atmosphere. The samples were characterized by transmission electron microscopy and X-ray diffraction. The nickel oxide nanoparticles were initially dispersed on the external surfaces of carbon nanotubes. Continuous calcination in an inert atmosphere caused the reduction of nickel oxide nanocrystals to metallic nickel nanoparticles, where carbon nanotubes functioned as reducing agent. The metallic nickel nanoparticles were deposited on the surface of nanotubes and they could be used as catalyst in homogeneous or heterogeneous reactions.

Aligned ZnO nanorod arrays and oriented ZnO nanoplates were synthesized on Si and Al substrates, respectively, using a hydrothermal method without any surfactant. The process involved the deposition of ZnO seeds on the substrate and the oriented growth of ZnO nanostructure in aqueous solution. The ZnO seeds were indispensable for the alignment of ZnO nanorods and TEM and XRD analysis confirmed that the ZnO rods are single crystalline grown along [001] direction. Al substrate caused formation of (001) surface dominated ZnO nanoplates, in which ZnO preferential growth direction was suppressed. The photoluminescence spectra of the as-grown ZnO products were measured to indicate their structural and optical quality. These oriented ZnO nanostructures are expected to be prospectively applied in nanodevices fabrication.

The present work describes a procedure for the preparation of iron oxide and carbide nanoparticles in carbon nanotube (CNT) matrix using the wet impregnation method and subsequent heat treatment in different atmosphere. In this way, two specific composites were produced with magnetite and cementite phase particles dispersed in CNTs, respectively, and cementite particles were encapsulated in graphene shells. As-prepared nanoparticles were all single crystalline and characterized by transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction. The magnetic properties of the resultant products were studied using vibrating sample magnetometer at room temperature.

Non-covalently functionalized carbon nanotubes are more attractive for multifunction composites because they preserve nearly all the nanotubes’ intrinsic properties and enhance the electroconductivity of polymer composites. However, It is seldom reported that they make dramatic improvement in mechanical properties. In this paper we have successfully prepared a poly(vinyl alcohol) (PVA) nanocomposite with a non-covalently functionalized carbon nanotube (DOC-MWNTs) using a simple method, which achieve a significant enhancement in mechanical properties. The tensile modulus and tensile yield strength of the PVA composite film containing 5 wt% DOC-MWNTs increased by 140% and 65%, respectively, comparing to the pure PVA film. FT-IR, TEM, SEM, and DSC were used to investigate the MWNTs and PVA/MWNTs nanocomposites. The results show that the separately dispersed DOC-MWNTs filler throughout the PVA matrix and the strong adhesion between the DOC-MWNTs filler and the PVA matrix are responsible for the significant reinforcement of the mechanical properties of the composite prepared.

Novel carbon nanohorns filled with single crystalline Cu nanocones (Cu-CNHs) have been synthesized using alkali-element doped Cu catalyst by CVD. X-ray diffraction (XRD) analysis reveals that Cu nanocones have face-centered cubic structure. Selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) indicate that these Cu nanocones are single crystalline in nature. Based on experimental results, a simple growth model is proposed in this paper.

CNTs-HDPE composites were prepared by the blend method. SEM was used to investigate the microstructure of the composites. The electrical and tribologic properties of the composites were studied respectively. The experiments showed that the percolation threshold of composites is about 3wt%, which is much lower than that of the carbon black-HDPE composites, and that the temperature-dependent electrical conductivity of composites had the PTC and double NTC characters, being also different from the carbon black-HDPE composites. These results are due to the unique structure and characters of CNTs. The frictional experiments demonstrated that the addition of CNTs would enhance the wear resistance of the composites.

High-purity nitrogen-doped multi-walled carbon nanotubes (MWCNTs) have been produced with a yield of more than 30 times the amount of the catalyst, using Co x Mg 1− x MoO 4 as catalyst and a methane–hydrogen–ammonia mixture as precursor. By controlling the flow-rate of ammonia during the chemical vapor deposition, the nitrogen concentration of 0.6 at.% to 3.2 at.% was obtained. X-ray photoelectron spectroscopy reveals that three different structures of the nitrogen atoms are involved in the nitrogen-doped MWCNTs, among which a graphite-like structure is dominant in these MWCNTs. Thermal gravimetric analyses show that the purity of the as-prepared MWCNTs is over 95%. High-resolution transmission electron microscopy analyses indicate that the MWCNTs have high graphitization degree. Our experimental results showed that the Co x Mg 1− x MoO 4 catalyst is ideal for the synthesis of high-quality nitrogen-doped MWCNTs because of its high catalytic activity.