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Two-dimensional (2D) porous materials with high specific surface area and ordered morphology exhibit great potential as supercapacitor electrodes. The fundamental understanding of the charge storage and charging dynamics of 2D porous materials can help the optimal design of supercapacitors. Herein, we investigated the energy storage, including the double layer and quantum capacitances, of supercapacitors with typical 2D porous graphynes in the ionic liquid electrolyte by combining molecular dynamics simulation and density functional theory. Simulations revealed that supercapacitors with porous graphyne electrodes could obtain excellent double-layer capacitances, but their total capacitances are limited by the low quantum capacitances. We further predicted boron-/nitrogen-doped graphynes and found that the new porous graphynes turn into good conductors after doping and could achieve a quite high quantum capacitance. The charging dynamics in nanoscale and capacitive performance in macroscale based on the predicted graphyne electrodes were evaluated by combining molecular simulation and transmission line model. Results demonstrate that both outstanding gravimetric and volumetric energy and power densities could be obtained in doped porous graphyne supercapacitors. These findings pave the way for understanding energy storage mechanisms and designing high-performance supercapacitors.

MoS2 has emerged as an attractive electrocatalyst for hydrogen evolution reaction (HER) although its performance still needs to be further enhanced, especially in alkaline solution due to inferior ability for water dissociation. Herein, we discover that coupling water-dissociation-active FeOOH with MoS2 grown on Ni3S2 nanowire arrays to achieve a core-shell Ni3S2@MoS2/FeOOH heterostructure can not only significantly accelerate the HER of MoS2, but also appreciably promote the OER activity of the catalyst. Systematic investigations on Ni3S2@MoS2/FeOOH and a series of delicately designed control catalysts reveal that such synergistically enhanced electrocatalytic performance for both OER and HER should be ascribed to the coupling effect and electronic modulation between FeOOH and MoS2. As a result, the prepared Ni3S2@MoS2/FeOOH exhibits small overpotentials of 95 mV for HER and 234 mV for OER at 10 mA cm−2. The alkaline electrolyzer using it as both anode and cathode only need a cell voltage of 1.57 V to output a stable current density of 10 mA cm−2, enabling it as an efficient bifunctional electrocatalyst for alkaline overall water splitting. The present strategy opens up opportunities to develop new efficient electrocatalysts for diverse applications by coupling OER-active electron-modulating component with highly-active HER electrocatalyst or vice versa.

Altres ajuts: ICN2 is funded by the CERCA Programme/Generalitat de Catalunya. Part of the present work has been performed in the framework of Universitat Autònoma de Barcelona Materials Science PhD program. TZ has received funding from the CSC-UAB PhD scholarship program. Non-enzymatic glucose sensors based on different Co-Ni-C composite materials were developed by pyrolysis of bimetallic or single metal based metal-organic frameworks (MOFs). The structure and composition of the resulting materials were explored by XRD, nitrogen adsorption/desorption isotherms, SEM, HRTEM and STEM-EELS. The electrochemical performance of the bimetallic MOF derived novel yolk-albumen-shell structure of Ni-Co@C (YASNiCo@C) stands out from these materials. The YASNiCo@C electrode exhibited a sensitivity of 1964 μA cm-2 mM-1 with the detection limit of 0.75 μM, a linear range from 5 μM to 1000 μM and good stability for the detection of glucose. These promising electrochemical performances prove that YASNiCo@C is a promising material for glucose sensors. Moreover, the strategy outlined in this work for the design of MOF based nanomaterials can also be used beyond glucose sensors.

Developing high-performance biomass-derived carbons and understanding the relationship between their structures and performance are highly desired for carbon-based supercapacitors. Herein, a wheat gluten-derived carbon with porous sheet-like structure, high specific surface area, and oxygen- and nitrogen-based heteroatom groups is fabricated. Their pore properties and heteroatom doping amount are adjusted through controlling the activation temperature. In aqueous electrolyte there is a significant synergistic effect between pore properties and heteroatom amount on the electrochemical performance of the gluten-derived carbon; while their performance is mainly determined by their pore properties in ionic liquid electrolytes. Besides, whatever in the aqueous and ionic liquid electrolytes ion sieving effect also affects their capacitive performance. The gluten-derived carbon prepared at 700 °C with reasonable pore properties and heteroatom amount shows the highest specific capacitance of 350 F g−1 at 0.5 A g−1 in 6 mol L−1 KOH. But the gluten-derived carbon prepared at 800 °C with the highest specific surface area of 2724 m2 g−1 possesses a high specific capacitance of 197 F g−1 at 0.25 A g−1 in the ionic liquid electrolyte. This work can provide a guideline for optimizing the performance of biomass-derived carbons through matching their pore properties and heteroatom with different electrolytes.

The poor surface performance of titanium alloys substantially limits their application in many fields, such as the petrochemical industry. To overcome this weakness, the Cu and Ni double layers were deposited on the surface of TC4 alloy by the electroplating method, and the isothermal diffusion process was performed at 700 &deg, C to enhance the binding ability between Cu and Ni layers. The isothermal diffusion behavior and microstructure of the coating were systematically analyzed, and tribological property and corrosion resistance of the coating were also evaluated to reveal the influence of isothermal diffusion on the surface performance. It was shown that multiple diffusion layers appeared on the Cu/Ni and Ni/Ti interface, and that NixTiy and CuxTiy phases were formed in the coating with the increase of diffusion time. More importantly, Kirkendall diffusion occurred when the diffusion time increased, which led to the formation of continuous microvoids and cracks in the diffusion layer, weakening the surface performance of the Cu/Ni coatings. This paper unveils the relationship between the microstructure of the Cu/Ni coatings and isothermal diffusion behavior, providing guidelines in preparing high performance surface coatings.

A novel tobacco rods-derived carbon (TC) has been prepared by hydrothermal carbonization and potassium hydroxide activation strategy for supercapacitors application. The physicochemical properties of TC are investigated by X-ray diffraction, Raman spectra, Scanning electron microscopy, Nitrogen adsorption–desorption isotherms, X-ray photoelectron spectroscopy, and four-probe tests. Results show TC derived from different tobacco rods possesses similar properties, such as amorphous state, high specific surface area, hierarchical porous structure, numerous heteroatom groups, and good electrical conductivity. The electrochemical characteristics of TC are examined via cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy measurements. In a three-electrode system, TC exhibits high capacitance with 286.6 F g−1 at 0.5 A g−1, excellent rate performance with 212.1 F g−1 even at 30 A g−1, and outstanding cyclic stability with 96% capacitance retention after 10,000 cycles at 5 A g−1. Furthermore, TC supercapacitor devices can deliver an energy density of 31.3 Wh kg−1 at 0.5 A g−1 and power density of 11.8 kW kg−1 at 15 A g−1. Therefore, this novel concept of tobacco use, namely tobacco rods from cigarette (the harmful) to high-performance carbon for supercapacitors (the beneficial), is an extremely promising strategy for developing high-performance carbon from renewable sources, and supporting the tobacco control.

The vane plasticating extruder (VPE) is a novel polymer processing equipment which is based upon elongational rheology. According to the basic structural analysis and movement interpretation, generation mechanism of elongational flow field was derived. Elongational effects during the controlled recovery of immiscible polymer blends, containing polystyrene (PS) matrix and linear low density polyethylene (LLDPE) as dispersed phase, were studied. The morphological results revealed the elongational effect of vane extruder. LLDPE morphology evolution was precisely predicted by a mathematical model. Elongational ratio and elongational strain via VPE were calculated separately, both of which established that the VPE does imposed elongational force field on polymer blends. DOI: http://dx.doi.org/10.5755/j01.mech.23.6.19855

Context: Tea (Camellia sinensis (L.) Kuntze [Theaceae]) is used to induce urination and inducing nervous excitation. Green and black teas have multifarious physiological functions. The different effects of green and black tea aqueous extracts (GTEs and BTEs) on hyperuricemia are not definitely reported. Objective: The different effects of GTEs and BTEs on lowering serum uric acid (UA) in hyperuricemic mice were determined. Materials and methods: Kunming mice were divided into nine groups (n = 6/each group). GTEs and BTEs at the doses of 0.5, 1 and 2 g/kg were orally administrated to mice for seven days, respectively. Hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA) activities as mechanisms of actions were assessed. Results: Research indicated that the LD50 of tea extract is greater than 2 g/kg in mice. UA levels were suppressed significantly with dose-dependent treatment of 0.5, 1 and 2 g/kg BTEs (up to 25.5%, 28.7% and 29.8%, respectively); the serum UA levels were decreased by GTEs but not significant. The activities of XOD and ADA in high dose (2 g/kg) groups of both GTEs and BTEs were notably lower than those of the model group. Discussion and conclusions: The results suggested that both GTEs and BTEs have hypouricaemic and renal protective effects on hyperuricemic mice and the latter one was better. Our study sheds light on the research and development of anti-hyperuricemic functional foods and drugs from tea.

On the basis of the forces on the differential element in the solids bed, a function between bulk density and pressure, and the nonisotropic pressure distribution in the element, an expression of pressure in the circumferential direction is derived. And the total power introduced through the positive conveying and the friction dragging conveying is also deduced. Experimental data are obtained using a self-developed and simplified vane extruder with an adjustable rotor eccentricity. The solids conveying mechanism in the solids compaction zone of a vane extruder is theoretically and semiempirically confirmed. Besides, the various portions of total power consumption including the power dissipated on the surfaces of the stator and baffles, the power used to build pressure and the power converted into rotational kinetic energy are derived. The effects of the eccentricity on the solids conveying are also discussed theoretically and semiempirically. POLYM. ENG. SCI., 55:719–728, 2015. © 2014 Society of Plastics Engineers

The effect of the electrodeposition temperature on the electrochemical performance of Ni(OH)2 electrode was investigated in this report. Ni(OH)2 was electrodeposited directly on nickel foam at different temperatures. The crystalline structure, morphology and specific surface area of the prepared Ni(OH)2 were characterized by X-ray powder diffraction (XRD), field emission scanning electronic microscopy (FESEM) and Brunauer–Emmett–Teller (BET). Electrochemical techniques such as cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectra (EIS) were carried out to systematically study the electrochemical performance of various Ni(OH)2 electrodes in 1 M KOH electrolyte. The results demonstrated that the electrodeposition temperature had obviously affected the properties of the Ni(OH)2. A pure α-Ni(OH)2 phase could be observed at low temperature. When the temperature increased to 65 °C, the β-Ni(OH)2 phase together with α-Ni(OH)2 phase were present. Moreover, the sample synthesized at 65 °C possessed a porous honeycomb-like microstructure and the corresponding specific capacitance was up to 3357 F g−1 at a charge–discharge current density of 4 A g−1, which suggested its potential application as an electrode material for supercapacitors.

Nanodiamond (ND)/poly (lactic acid) (PLA) nanocomposites with potential for biological and biomedical applications were prepared by using melting compound methods. By means of transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analyses (TGA), Dynamic mechanical analyses (DMA), Differential scanning calorimetry (DSC) and Tensile test, the ND/PLA nanocomposites were investigated, and thus the effect of ND on the structural, thermal and mechanical properties of polymer matrix was demonstrated for the first time. Experimental results showed that the mechanical properties and thermal stability of PLA matrix were significantly improved, as ND was incorporated into the PLA matrix. For example, the storage modulus (E′) of 3 wt% ND/PLA nanocomposites was 0.7 GPa at 130 °C which was 75% higher than that of neat PLA, and the initial thermal decomposition was delayed 10.1 °C for 1 wt% ND/PLA nanocomposites compared with the neat PLA. These improvements could be ascribed to the outstanding physical properties of ND, homogeneous dispersion of ND nanoclusters, unique ND bridge morphology and good adhesion between PLA matrix and ND in the ND/PLA nanocomposites.

To improve the performance of direct ethanol fuel cells (DEFCs), a three-dimensional (3D), hierarchically structured Pd electrode has been successfully fabricated by directly electrodepositing Pd nanoparticles on the nickel foam (referred as Pd/Nickel foam electrode hereinafter). The electrochemical properties of the as-prepared electrode for ethanol oxidation have been investigated by cyclic voltammetry (CV). The results show that the oxidation peak current density of the Pd/Nickel foam electrode is 107.7 mA cm −2 , above 8 times than that of Pd film electrode at the same Pd loading (0.11 mg cm −2 ), and a 90 mV negative shift of the onset potential is found on the Pd/Nickel foam electrode compared with the Pd film electrode. Furthermore, the peak current density of the 500th cycle remains 98.1% of the maximum value for the Pd/Nickel foam electrode after a 500-cycle test, whereas it is only 14.2% for the Pd film. The improved electrocatalytic activity and excellent stability of the Pd/Nickel foam electrode make it a favorable platform for direct ethanol fuel cell applications.

Animal silks and poly(lactic acid) (PLA) are potential materials for biomedical and bioengineering applications. Biodegradability of these materials thus is important to minimize any extra pain of patients with bone defects due to second operations for removing those non-biodegradable implants. However, the control of their biodegradability and mechanical properties is essential to ensure a smooth load transfer from a depredating implant to neo-tissue. In this study, a biodegradation test on silk/PLA biocomposites was performed. Physical and mechanical properties, pH condition of the surrounding fluid and the morphology of fractured samples were studied at specific time points. It was found that there were no significant differences between the pH values of the solution and weight loss for both pure PLA samples and silk/PLA biocomposites. Moreover, with the reinforcement of silk fiber, stiffness and ductility of PLA were enhanced and a faster biodegradation rate was observed within the 4-month biodegradation period. It can be concluded that the biodegradation rate of implants can be altered and their mechanical properties can be enhanced by incorporation of silk fiber. This is a potential solution to match with the degradation rate of PLA to the regeneration rate of neo-tissues.

Chicken feather fiber (CFF)/reinforced poly(lactic acid) (PLA) composites were processed using a twin-screw extruder and an injection molder. The tensile moduli of CFF/PLA composites with different CFF content (2, 5, 8 and 10 wt%) were found to be higher than that of pure PLA, and a maximum value of 4.2 GPa ( 16 % ↑ ) was attained with 5 wt% of CFF without causing any substantial weight increment. The morphology, evaluated by scanning electron microscopy (SEM), indicated that an uniform dispersion of CFF in the PLA matrix existed. The mechanical and thermal properties of pure PLA and CFF/PLA composites were compared using dynamic mechanical analysis (DMA), thermomechanical analysis (TMA) and thermogravimetric analysis (TGA). DMA results revealed that the storage modulus of the composites increased with respect to the pure polymer, whereas the mechanical loss factor (tan δ ) decreased. The results of TGA experiments indicated that the addition of CFF enhanced the thermal stability of the composites as compared to pure PLA. The outcome obtained from this study is believed to assist the development of environmentally-friendly composites from biodegradable polymers, especially for converting agricultural waste – chicken feather into useful products.

High capacitance at a high charge–discharge current density of 50 mA/cm2 for a new type of electrochemical supercapacitor cobalt sulfide (CoSx) have been studied for the first time. The CoSx was prepared by a very simply chemical precipitation method. The electrochemical capacitance performance of this compound was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge tests with a three-electrode system. The results show that CoSx has excellent electrochemical capacitive characteristic with potential range −0.3 ∼ 0.35 V (versus SCE) in 6 M KOH solution. Charge–discharge behaviors have been observed with the highest specific capacitance values of 475 F/g at the current density of 5 mA/cm2, even at the high current density of 50 mA/cm2, CoSx also shows the high specific capacitance values of 369 F/g. Keywords: Supercapacitors, Cobalt sulfide, High capacitance, Current density, Mechanism

Cobalt silicate hydroxide (Co-3 [Si2O5](2) [OH](2)) was prepared by chemical method for use in electrochemical capacitors. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests indicate that the material was pure hexagonal phase with uniform nanometer size distribution. Cyclic voltammeter (CV) and galvanostatic charge/discharge measurements show that the cobalt silicate hydroxide-based electrode has stable electrochemical capacitor proper-ties between potential range of 0.1-0.55 V with a maximum specific capacitance of 237 F g(-1) in alkaline solution and 95% of capacity efficiency was reached after 150 cycles. Electrochemical impedance spectra (EIS) investigation illustrates that the capacitance of the test electrode was mainly consisted of pseudo-capacitance, which was caused by underpotential deposition of H3O+ at the electrode surface. (c) 2006 Published by Elsevier B.V.

Highly ordered hydroxyapatite (HA) nanowire arrays were synthesized using porous anodic aluminum oxide (AAO) template from sol-gel solution containing P2O5 and Ca(NO3)2. Theresults of transmission electron microscopy (TEM) and scanning electron microscopy(SEM) revealed that the obtained HA nanowires had a uniform length and diameter andformed highly ordered arrays, which were determined by the pore diameter and thethickness of the applied AAO template. The results of X-ray diffraction (XRD) and X-rayphotoelectron spectroscopy (XPS) demonstrated that the major component was HA. Theselected-area electron diffraction (SAED) results indicated that HA was a polycrystallinestructure. This novel method of preparing highly ordered HA nanowires with a large areamight be important for many applications in biomaterials.

Objective To explore the incidence, types of onset, and risk factors of posttraumatic epilepsy (PTE). Methods This is a retrospective follow-up study of patients discharged from the Affiliated Hospital of the Medical College of the Chinese People's Armed Police Forces between September 2004 and September 2008 with a diagnosis of traumatic brain injury (TBI). Results Complete clinical information was available on 2826 patients. Of the 2826 TBI patients, 141 developed PTE, providing an incidence rate of 5.0%. Twenty-four cases (0.8%) had posttraumatic seizures (PTS), of which 16 (66.7%) continued to experience after the acute phase of their TBI, accounting for 5.0% of the total PTE cases. A total of 125 cases (88.7%) were diagnosed as presenting with late-stage seizures, occurring from 10 days to three years after TBI (93/141 (66.0%) presented within six months after the TBI, 14/141 (9.9%) between six and twelve months, 22/141 (15.7%) between one and two years and only 12/141 (8.5%) between two and three years after the TBI. The severity of PTE was rated mild, medium, and severe in 3.6%, 6.9%, and 17% of the TBI patients. Multiple regression analysis was carried out to identify factors contributing to the risk of developing PTE. Five parameters contributed to the model: Older age, greater severity of brain injury, abnormal neuroimaging, surgical treatment, and early-stage seizures. Conclusion Age, severity of brain injury, neuroimaging results, treatment methods, and early-stage seizures are independent risk factors of PTE.

To study the sub-classification of temporal lobe epilepsy (TLE) and clinical and etiological characteristics thereof.The clinical data of 190 patients with TLE, aged 1.5 approximately 67, were analyzed. The sub-classification was based on clinical manifestations and electroencephalographic recording. The etiology of TLE was mainly concluded from both clinical history and neuroimaging.172 patients were subclassified as with mesial temporal lobe epilepsy (MTLE), of which 62.2% had auras such as epigastric abnormal sensation and 67.4% had automatism, especially oroalimentary automatism. The electroencephalography recording of the MTLE patients showed interictal epileptic paroxysm discharges over the anterior or mid-anterior temporal areas. The main etiological factors related to MTLE were hippocampal sclerosis, intracranial infection, tumor, cerebrovascular disease, and trauma. Ten patients were subclassified as with lateral temporal lobe epilepsy (LTLE), all presenting auras such as acoust. The electroencephalography recording showed interictal epileptic paroxysm discharges over the posterior or mid-posterior temporal areas. The main etiological factors were trauma, tumor, and atrophy in the LTLE group. Eight patients were unable to be sub-classified.Electroencephalography is the main base for classification of TLE. Subclassification of TLE is important in the selection of treatment strategies.

To investigate the changes of gene expression in early stage of hemitransection of spinal cord and the regulatory effects of the traditional Chinese mixture Suifukang (SFK) on these changes.Eighty-six adult male SD rats were randomly divided into 3 groups: Suifukang group (Group S, n = 31, administered with SFK 3 days before the hemitransection at the dose of 2.5 g crude drugs/100 kg body weight QD and then 4 h and 8 h after hemitransection), model group (Group M, n = 45, administered with normal saline in the manner as in Group S), and normal control group (Group N, n = 10, without any treatment). The rats of Groups S and M underwent hemitransection of spinal cord at the level T12 three days before treatment. Twenty-four hours after the spinal cord injury (SCI), the rats were anesthetized and the injured tissues of Groups S and M and the corresponding tissues of Group N were removed. Total RNA was extracted, mRNA was purified and marked by Cy3 or Cy5 fluorescence labeling to synthesize cDNA hybridized probe that was hybridized with Biostars gene chip. Then the chip was scanned with ScanArray500 scanning apparatus. The data were analyzed by Imagene3.0 software.There were 139 differentially expressed genes in Group M, 83 up-regulated and 56 down-regulated, involved in multifarious functions, such as cell metabolism, especially lipid metabolism, and regulation of ionic channel, immunity and defense, cytoskeleton protein, extracellular matrix, cell cycle, etc. There were 37 differentially expressed gene in Group S, 11 up-regulated, such as such Anxal, Ca(2+)-ATPase, IL-1 beta, Ofp, and 26 down-regulated, such as HSP-70 and Psap, several being key genes related to protection and regeneration of neuron.In the early stage after SCI many genes related to nervous degeneration, necrosis, traumatic inflammation, secondary injury of spinal cord, and aborted regeneration, etc, are expressed differentially. SFK regulates the changes of gene expression induced by SCI, thus initiating the protective effect of nervous tissues and promoting and supporting the regeneration of injured nervous tissues.