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Recurrence of esophageal cancer in the brain is rare but associated with a poor prognosis. Identification of risk factors for isolated brain metastasis of esophageal cancer (iBMEC) after surgical treatment may guide surveillance recommendations to enable early identification and intervention before widespread metastasis. Patients with iBMEC (n = 38) were identified from a prospective database of patients with esophageal cancer who underwent esophagectomy. Risk factors for iBMEC were identified using competing risk regression analysis. In a cohort of 1760 patients, 39% recurred and iBMEC developed in 2% by the end of the study. Survival in patients with iBMEC was similar to survival in patients with distant recurrence (median overall survival, 0.95 years; 95% confidence interval, 0.6-1.5 years). More than half of patients with iBMEC were diagnosed within 1 year postoperatively. All 38 patients with iBMEC had received neoadjuvant therapy before surgery. Pathologic complete response (PCR) to neoadjuvant therapy was associated with improved survival after brain recurrence (median overall survival, 1.56 vs 0.66 years; P =.019). In patients with PCR, iBMEC may represent true isolated recurrence, whereas in those with residual nodal disease, iBMEC may actually be the first observed site of widespread metastasis. Patients who receive neoadjuvant therapy, especially with PCR, may benefit from brain imaging, both preoperatively and with routine surveillance. [ABSTRACT FROM AUTHOR]

Abstract In this work, CdO-Ag-ZnO nanocomposites with hierarchically porous structure and large surface area were successfully fabricated by solution combustion synthesis (SCS) method. Crystalline structure, morphology, surface chemical states and specific surface area were investigated by XRD, SEM, TEM, XPS and BET techniques, respectively. Sensors fabricated from CdO-Ag-ZnO nanocomposites were made based on indirect heating method, which showed superior sensing properties in detecting different concentration of volatile organic compounds (VOCs). In contrast with singular ZnO, gas-sensing experiment results reveal that the addition of CdO and Ag effectively decreases optimum working temperature, increases gas response value and shortens response and recovery time. What's more, other gas-sensing properties including repeatability, sensitivity and long-term stability are also discussed in this research. Particularly, gas sensor based on 10 mol% CdO-Ag-ZnO shows modest gas-sensing performance to VOCs at the operating temperature of 200 °C, and its gas response values are 198.63, 156.07, 53.04, 64.23, 183.65 towards 100 ppm formaldehyde, ethanol, acetone, methanol and isopropanol, respectively, indicating it a promising candidate in detecting VOCs. Superior sensing property is mainly ascribed to large specific surface area, special porous surface morphology, unique combination of nanocomposites and good catalytic ability of metallic Ag. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using PTASA to promote PTL pyrolysis for high-quality syngas was firstly proposed. • The kinetic mechanism of PTASA in the pyrolysis of PTL was revealed. • PTASA mainly decreased the activation energy of Lignin in PTL by19%. • High-quality syngas increased evidently from 0.415 to 0.523 L/g with PTASA. • Inherent minerals in PTASA could break macromolecule bonds to promote PTL pyrolysis. To improve pyrolysis syngas of Phoenix Tree's Leaves (PTL), the synergistic effect of Purified Terephthalic Acid Sludge Ash (PTASA) was comprehensively investigated. In kinetics analysis, the thermal decomposition of PTL could be divided into three pseudoreactions while PTL + PTASA was with four pseudoreactions owing to the decomposition of CaCO 3 as well as the reduction of inherent metal compounds (Co(II), Mn(III, IV), etc). Meanwhile, the reaction models for pseudoreaction 1 (P1) ∼ pseudoreaction 4 (P4) were fitted as D3, R2 and D3, and A15, respectively. The Ea (average activation energy) of PTL + PTASA during pyrolysis (200 ∼ 600 °C) was 6.2 % lower than the monopyrolysis which was mainly caused by the decrease of Ea in the decomposition of lignin. In addition, the crystal structure e.g. CaMnO 3 (ABO 3), Ca 3 Co 2 O 6 (A 3 BB'O 6), and CoO in PTASA could effectively promote the production of high-quality syngas from 41.34 % to 61.76 %. Moreover, the reaction pathways in pyrolysis of PTL + PTASA showed that the PTASA could promote the C C bond, C O bond, and C–H bond breaking of the macromolecules, e.g. anhydrosugars, N-containing compounds, and aldehydes, to produce the small molecules and release syngas. This study could provide a useful strategy for clean, valuable, and sustainable resource utilization of waste resources. [ABSTRACT FROM AUTHOR]

A facile, cost-effective, template-free chemical method was developed for the synthesis of β -Co(OH) 2 nanoplatelets under the different preparation conditions. The morphology and microstructure of as-synthesized samples were examined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS), respectively. The observations revealed the formation of a single phase of the hexagonal brucite-like β -Co(OH) 2 , which had an irregular hexagonal disk with angles of adjacent edges of 120°, edge lengths ranging from 200 to 300 nm, and thicknesses of 20–40 nm. When investigated as catalyst for CO oxidation, the β -Co(OH) 2 nanoplatelets exhibited good catalytic activity for CO. Among β -Co(OH) 2 nanoplatelets, the sample prepared at 100 °C for 8 h performed the best, giving the T 100% (the temperature required for achieving a CO of 100%) of 120 °C for the oxidation of CO. There are good correlations of Co 3+ /Co 2+ , the absorbed O x − ions and surface OH group with catalytic activity of the samples for CO oxidation. [ABSTRACT FROM AUTHOR]

Macro-/nanoporous Al-doping ZnO powders with enhanced gas sensing properties are prepared by a solution combustion method using Zn(CH 3 COO) 2 ·2H 2 O, Zn(NO 3 ) 2 ·6H 2 O, Al(NO 3 ) 3 ·9H 2 O, N 2 H 4 ·H 2 O and C 2 H 5 NO 2 as precursors. Characterization by TEM, SEM and BET techniques demonstrates that the Al-doping ZnO powders have a coral-like morphology with a hierarchically porous structure from macro pores, with the wall containing smaller mesopores. The gas-sensing characteristics of the ZnO samples with different Al-doping concentrations are investigated and the results indicate that the gas sensor prepared from 2.5 at% Al doping ZnO powders shows the highest gas sensitivity and selectivity towards n -butanol. A maximum gas response of 751.95 towards 100 ppm n -butanol is achieved at the operating temperature of 300 °C. The mechanisms of responses are also proposed considering the unique material structure. [ABSTRACT FROM AUTHOR]

Pure and Al-doped macro-/nanoporous ZnO were synthesized via solution combustion method by using zincacetate dihydrate (Zn(CH 3 COO) 2 ·2H 2 O), zinc nitrate hexahydrate (Zn(NO 3 ) 2 6H 2 O), aluminum nitrate nonahydrate (Al(NO 3 ) 3 ·9H 2 O), hydrazine hydrate (N 2 H 4 ·H 2 O) and glycine (C 2 H 5 NO 2 ) as precursors. The morphology, structure and catalytic properties of the as-synthesized macro-/nanoporous products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy, Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption and Fourier transform infrared spectroscopy (FTIR), respectively. Pure and Al-doped ZnO have coral-like shape with the pores size ranging from several nanometers to ten micrometers. The walls of the macropores contain smaller nanopores, exhibiting the hierarchically porous morphology. The catalytic activities of the as-synthesized samples were tested by measuring the degradation efficiency of azo dye Congo red (CR) under visible light, UV light and dark light, respectively. The results show excellent removal capacity for organic pollutants CR in wastewater. Macro-/nanoporous Al-ZnO with different contents of Al have better catalytic degradation efficiency than pure ZnO. The experimental results indicate the potential use of macro-/nanoporous Al-ZnO for catalytic degradation of Congo red dye in different environments, which provides a potentially low-cost alternative for the remediation of azo-dye effluents. [ABSTRACT FROM AUTHOR]

Hollow CuO fibers were successfully fabricated using a facile solution combustion method by incorporating cotton fibers as biotemplate. XRD patterns along with Rietveld refinement confirm the formation of CuO with monoclinic phase. The length of the as-synthesized CuO fibers is at micrometer scale, and the average fiber diameter ranges from several nanometers up to order of micrometers. After combustion reaction, a large amount of coalescent particles left on the surface of the cotton fibers to form porous walls of CuO. By totally removing cotton body at 600 °C, hollow CuO fibers were obtained. A possible growth mechanism of hollow CuO fibers using cotton fibers as templates was given based on experimental data. When used as a sensing material in gas sensor, it exhibited a superior sensitivity and good selectivity toward low-ppm-level (1–100 ppm) n -propanol. Theses findings not only provide a novel approach to fabricate hollow CuO fibers via a solution combustion route, but also explore a promising gas sensor toward n -propanol. [ABSTRACT FROM AUTHOR]

Despite the unsettled mechanism of electricity generation from the continuous flow of liquids on a surface, the charge-discharge theory has been widely accepted for alternating current (AC) generation from a moving droplet. It has been recently extended to rationalize direct current (DC) generation across a droplet moving between two different materials. By designing a reconfigurable contact between a metal wire and a water droplet moving on graphene, we show that the charge-discharge theory cannot explain the reversal of current when water-metal interfaces switch from dynamic to static. All experiments can be described after we distinguish a dynamic from a static interface and generalize the photovoltaic-like effect to all dynamic junctions: excited electrons and holes in a moving interface will be separated and swept under the built-in electrical field, leading to a DC response. This generalized theory will lead to an understanding and the design of efficient electricity generation based on interfacial charge transfer. [Display omitted] • Novel droplet nanogenerators with reversible configurations between dynamic and static liquid-solid junctions. • Resolved the debate over mechanism of DC generation from moving liquid-solid interfaces. • Generalized the mechanism of DC generation to any moving heterojunctions or interfaces. • Identified a major flaw in the well-accepted charge-discharge theory for liquid droplet AC generators. [ABSTRACT FROM AUTHOR]

Pyrolysis is an effective way for the sludge harmless, reduction treatment and resource utilization. In this study, the pyrolysis kinetics and thermodynamics of PTA sludge was evaluated. Afterword, a cyclic in-situ catalytic pyrolysis of PTA sludge by using recycled char as a catalyst was conducted. The product characterization, e.g. pyrolysis syngas as well as the catalytic effect of pyrolysis char, were analyzed. The results demonstrated that the Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), and Starink model-free methods have good agreement on kinetic parameters, the average activation energy was calculated at 295.18, 286.62, and 290.55 kJ/mol, respectively. Meanwhile, thermodynamic parameters, e.g. the variations in enthalpy (Δ H), entropy (Δ S), and Gibbs free energy (Δ G), were evaluated based on the deduced kinetic results, whereby the suitable pyrolysis temperature was determined at 973 K. The results of cyclic in-situ catalytic pyrolysis showed that the pyrolysis char could promote tar cracking, which greatly increased the yield of pyrolysis syngas. After five rounds of in-situ catalytic pyrolysis, the yield of pyrolysis syngas increased from 0.089 L/g to 0.176 L/g and the carbon conversion increased from 24.8% to 36.5%, respectively. • A cyclic in-situ catalytic pyrolysis with recycled char as a catalyst was proposed. • The pyrolysis kinetics and thermodynamics of PTA sludge were evaluated. • The carbon conversion was increased to 36.5% by five rounds of in-situ pyrolysis. • The char has effects on improving the yield of syngas by promoting cracking of tar. [ABSTRACT FROM AUTHOR]

One dimensional Mn–Ce–O x composite nanomaterials with various Mn contents were synthesized successfully by a hydrothermal method. The impacts of Mn contents on their morphologies and physical properties were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The analysis reveals that the obtained composites are one-dimensional (1D) rod-like nanostructures. The catalytic behaviors of Mn–Ce–O x nanomaterials were investigated for CO oxidation. The Mn–Ce–O x catalysts were found to be more active than catalysts based on ceria alone. The catalytic activities of all one dimensional Mn–Ce–O x materials for CO conversion are quite high (142< T 50% <229 °C). Among the obtained nanocatalysts, the Mn–Ce–O x composite nanomaterials with 40 wt% Mn exhibit the best catalytic activity and the 50% CO conversion can be reached at 142 °C. The presence of transition metal element Mn can promote the production of oxygen vacancies and improve oxygen mobility, which result in enhancing the oxygen-storage capacity of the one dimensional Mn–Ce–O x materials and its catalytic performance for CO conversion. [ABSTRACT FROM AUTHOR]

• Chemical looping gasification of pine sawdust by Fe 2 O 3 -rich sludge ash was studied. • Thermal behaviors and gasification performance were analyzed by TGA and DCLG tests. • Interactions between pine sawdust and sludge ash exist, are related to blending ratio. • SA presence and high ratio promote the conversion of PS, but reduce DCLG performance. • DCLG reactivity was improved as the temperature rose, and kept stable for multiples. The thermal characteristics and kinetic parameters of direct chemical looping gasification (DCLG) of pine sawdust (PS) were researched using a TGA at a well-defined heating rate. The three-phase product yields, syngas contents, DCLG performances, and multiple reactions were analyzed by a DCLG evaluation apparatus coupled with a gas chromatography (GC). TGA results indicated that, as the SA blending ratio was at 10%, the interactions between PS and SA mainly occurred at lower temperatures, while with the SA ratio increasing, more interactions also happened at the higher temperatures. The kinetics analysis results indicated that the activation energies of the first thermal decomposition zone of PS were independent with the SA ratios, while the values of the second and third zone were related to them. Through DCLG evaluation experiments, it was found that the SA presence, and the increase in SA ratios would promote the conversion of PS, while decrease the gasification performance. As the gasification temperature increased, the DCLG performance of PS would be improved, but the highest heating value of syngas produced would be obtained at 750 °C. The multiple DCLG experiments showed that the reaction performance of Fe 2 O 3 -rich sludge ash as an oxygen carrier could almost keep stable. The research results of this paper could give some useful guides for the potential application of Fe 2 O 3 -rich sludge ash as an oxygen carrier in direct chemical looping gasification of biomass feedstock. [ABSTRACT FROM AUTHOR]

• The high-temperature gasification and melting properties of PRPS were studied. • The PRPS prepared at 650 °C shows the best gasification reactivity. • The high-yield effective gas (CO + H 2) was found in the N 2 /CO 2 atmosphere. • The high-density of slag and reduction of PRPS was obtained in the N 2 /CO 2 atmosphere. High-temperature gasification and melting is a promising technology for the harmless disposal and resource utilization of hazardous organic solid wastes. In this study, the high-temperature gasification and melting properties of pyrolysis residues from petrochemical sludge (PRPS) were experimentally investigated. Firstly, the PRPSs in pyrolysis temperatures of 500–700 °C were prepared. The gasification reactivity of PRPSs was investigated through micropolitics pore structure and Raman spectrum analysis. The results show that the PRPS prepared at 650 °C has the best gasification reactivity, with both large surface area and more complete porous structure, and more disordered carbon microstructures. Then, based on the PRPS sample prepared at 650 °C, the effects of the gasification temperature (1100–1400 °C) and atmosphere (N 2 , H 2 O, and CO 2) were studied. In the atmosphere of 40 vol.%N 2 /30 vol.%CO 2 /30 vol.%H 2 O, the yield of effective gas (CO+H 2) began to decrease when the temperature was above 1200 °C. With the increase of temperature (1300–1400 °C), high-density slag of PRPS was observed. At the temperature of 1400 °C, the highest yield of effective gas (CO+H 2), the high-density slag, and the reduction of PRPS were obtained in the atmosphere of 40 vol.%N 2 /60 vol.%CO 2. In this condition, the high CO is conducive to form FeO as fluxing. Moreover, the stable mineral phases (CaSiO 3 , CaSi 2 O 7 , etc.) were detected, which should perform a good solidification effect of heavy metals in the slag. [ABSTRACT FROM AUTHOR]

Developing efficient and stable oxygen evolution reaction (OER) catalysts that can work well at high current densities for seawater electrolysis is desirable but remains a significant challenge. Here a novel and scalable strategy is developed to synthesize partially amorphous boron-modified cobalt iron layered double hydroxides (B-Co 2 Fe LDH). Benefiting from enhanced electronic kinetics and abundant active sites, this hierarchical nanosheet-nanoflake-structured B-Co 2 Fe LDH catalyst shows superb OER catalytic activity, requiring overpotentials of 205 and 246 mV to drive current densities of 10 and 100 mA cm−2, respectively, in 1 M KOH, along with a small Tafel slope of 39.2 mV dec−1. Its partial amorphousness feature leads to enhanced stability and corrosion resistance, which help the B-Co 2 Fe LDH catalyst to work well in the critical seawater condition. It requires overpotentials of 310 and 376 mV to drive current densities of 100 and 500 mA cm−2, respectively, in 1 M KOH seawater and can work continuously for 100 h without producing any hypochlorite. This work can enable the development of LDH catalysts for highly selective seawater oxidation using a general approach. [Display omitted] • A novel strategy is developed to synthesize partially amorphous boron-modified cobalt iron layered double hydroxides. • The B-Co 2 Fe LDH catalyst has a hierarchical nanosheet-nanoflake structure to expose active sites with strong corrosion resistance. • It requires low overpotential and shows excellent stability for OER in alkaline seawater. • In situ Raman and post-OER analysis are applied to analyze the transformation of B-Co 2 Fe LDH during OER. [ABSTRACT FROM AUTHOR]

Copper, as an essential element in human body, can have adverse impact on environment and healthy individuals if it is excessive. So it is necessary to establish a rapid and effective method for detecting Cu2+. In this work, we describe a method for determination of Cu2+ based on water-soluble ZnO quantum dots (QDs) modified with (3-aminopropyl)triethoxysilane (APTEs). The ZnO QDs functionalized with APTEs (NH 2 –ZnO QDs) synthesized by a simple sol-gel method and displayed strong yellow-green fluorescence with a peak at 535 nm under 350 nm excitation. High-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, luminescence, and UV–visible absorption spectroscopy were used to characterize the NH 2 –ZnO QDs. In addition, the emission from NH 2 –ZnO QDs was selectively quenched upon addition of Cu2+. Therefore, this finding was used to design a fluorescent probe based on NH 2 –ZnO QDs to detect Cu2+ in water solution, and the linear relationships were 2–20 nM and 1–100 μM respectively, with detection limit for Cu2+ at 1.72 nM (on the basis of 3σ/slope criterion). This fluorescent probe had also been applied in real water sample to testify its availability in drinking water. Furthermore, the quenching mechanism was studied by measurements of UV–visible absorption spectra and fluorescent lifetime of ZnO QDs, which may be attributed to the aggregation induced by Cu2+ and the dynamic quenching existing energy transfer between QDs and Cu2+. (3-aminopropyl)triethoxysilane modified water-soluble ZnO quantum dots synthesized by simple sol-gel method exhibit the excellently selective and sensitive fluorometric determination to Cu2+. Image 1 • Water-soluble NH 2 –ZnO QDs were synthesized by facile hydrothermal method. • Fluorometric determination of Cu2+ shows higher sensitivity and wider detection limitation. • Quenching mechanism associates to the coordination interaction between NH 2 –ZnO QDs and Cu2+. • NH 2 –ZnO QDs will be also helpful for the design of fluorometric determination of Cu2+. [ABSTRACT FROM AUTHOR]

• Duplex S-N curve associated with surface and subsurface failures under R = 0 is more obvious. • Deflection of crack surfaces contributes to the slow crack growth especially in the FCA. • Subsurface failure mechanism with the determination of stress intensity factors is elucidated. • An energy-based life prediction approach with crack nucleation and growth is proposed. Fully reversed and pulsating tension fatigue tests were performed to clarify the subsurface failure behavior of TC11 titanium alloy in high-cycle and very-high-cycle regimes. The deflection of crack surfaces induces the premature contact of crack surfaces and slow crack growth. The whole failure processes mainly include: (i) nucleation of microcracks, (ii) coalescence and growth of microcracks, (iii) formation of facet cluster area, (iv) early macrocrack growth, (v) formation of fisheye, (vi) unstable macrocrack growth and (vii) momentary fracture. Based on the modeling of crack nucleation and growth, an energy-based approach is well proposed to predict the total fatigue life. [ABSTRACT FROM AUTHOR]

SnO 2 is a typical metal oxide semiconductor gas sensitive material, which has been studied deeply. However, pure SnO 2 sensing materials usually have good performance at high operating temperatures. In this study, we reported an n-butanol sensor with high selectivity and fast response based on SnO 2 submicron porous cube prepared by heating and decomposing the Sn-based metal-organic framework material (Sn-MOF) in air at a certain temperature. SnO 2 submicron porous cube prepared at 450 °C shows good response and selectivity for n-butanol. And it has a response (%) of 175% to 100 ppm n-butanol and a relatively fast response/recovery time of 184 s/183 s at room temperature. The (110) crystal plane with sufficient oxygen-rich vacancy can adsorb O 2 and n-butanol molecules more effectively. Therefore, its sensitivity to n-butanol gas can be significantly improved. This work provides a good idea for further research on pure metal oxide semiconductor room temperature gas sensors. [ABSTRACT FROM AUTHOR]

ZnO hollow spheres with high crystallinity were prepared successfully via a simple template process using ZnCl 2 , carbamide and polystyrene spheres (PSS) as raw materials. The structural and morphological characterizations of the samples were carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. Indirect-heating sensor using ZnO hollow spheres as sensing materials was fabricated on an alumina tube with Au electrodes and Pt wires. The gas sensing properties of the as-synthesized ZnO hollow spheres for n -butanol were investigated. It is shown that the sensor exhibited good sensing performances, characterized by high response, very short response time, and stability to n -butanol gas at operating temperature of 385 °C. These results indicate that the ZnO hollow spheres are highly promising candidates for practical detectors for n -butanol. [ABSTRACT FROM AUTHOR]

As a new methanol sensing material, the composite of palladium-platinum-In 2 O 3 composited nanocrystalline SnO 2 was successfully obtained by a solid-phase reaction method. The phase composition and the unique structure of as-prepared SnO 2 -Pd-Pt-In 2 O 3 composite were comprehensively characterized using the techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The results of gas sensing properties indicate that the sensor based on the as-prepared SnO 2 -Pd-Pt-In 2 O 3 composite shows the ultra-high response to methanol at an optimal operating temperature of 160 °C when the mass ratio of SnO 2 , Pd, Pt and In 2 O 3 is 100:0.8:2:30. The gas response toward 100 ppm of methanol reaches as high as 320.73. The detection limit of the sensor is estimated to be 0.1 ppm. The sensor also exhibited good response-recovery properties, selectivity, remarkable repeatability and stability, suggesting its greatly promising application in gas sensing. This work could stimulate an effective means to fabricate methanol sensor with superior performance. At the same time, a possible sensing mechanism of the SnO 2 -Pd-Pt-In 2 O 3 composite is discussed. [ABSTRACT FROM AUTHOR]

Abstract Co(OH) 2 @FeCo 2 O 4 nanocomposite was successfully synthesized via a facile one-step hydrothermal reaction without thermal treatment. The structure and chemical composition of as-synthesized Co(OH) 2 @FeCo 2 O 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. The results show the FeCo 2 O 4 nanosheets are covered with the Co(OH) 2 nanoparticles and the BET show the nanocomposite possess the mesoporous structure with specific surface area and total pore volume are 93.071 m2 g−1 and 0.37 cm3 g−1, respectively. In addition, the electrochemical performances were investigated in a three-electrode system to evaluate the material. The as-synthesized Co(OH) 2 @FeCo 2 O 4 nanocomposite exhibits a high specific capacitance of 1173.43 F g−1 at 1 A g−1 and remarkable cycling stability with 95.4% capacitance retention after 5000 cycles. The results show the higher capacitance and longer cycle performance, compared with the Co(OH) 2 and FeCo 2 O 4 , respectively. This remarkable electrochemical performances were mainly due to mesoporous structure and the synergistic effect of Co(OH) 2 and FeCo 2 O 4. It means that this nanostructure Co(OH) 2 @FeCo 2 O 4 synthesized by this simple and cost-effective method would have more hopeful prospects in energy storage applications. Graphical abstract Co(OH) 2 @FeCo 2 O 4 nanocomposite applied as electrode of supercapacitor shows an impressive enhancement of the performance including the areal capacitance and cycling stability. Image 1 [ABSTRACT FROM AUTHOR]

Highlights • The rougher morphology of FGA reveals the rather distorted crack growth path. • A fatigue strength evaluation model is developed. • The predicted crack growth rate reflects the discontinuous crack growth behavior. • An assessment method is proposed for predicting allowable fatigue strength. Abstract A fatigue assessment approach for interior inclusion-FGA (fine granular area)-fisheye induced fracture was proposed through experimental investigation of very high cycle fatigue properties of two high-strength low-alloy steels. The rougher morphology of FGA reveals the rather distorted crack growth path and slow crack growth rate. A strength evaluation model related to defect size and fatigue life was developed, using which the predicted results are in agreement with the experimental results. Based on the modelling of micro-crack growth rate, the evaluated value can be less than the magnitude of one Burger's vector, which reflects the discontinuous crack growth behavior within FGA. [ABSTRACT FROM AUTHOR]

The raspberry-like SnO 2 hollow nanostructure was synthesized by a simple hydrothermal method. The composition, microstructure, morphology, surface area and chemical states are investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N 2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS), respectively. The characterization results show that the raspberry-like SnO 2 with a diameter of about 60 nm is composed of numerous SnO 2 nanoparticles with grain size about 8 nm. The raspberry-like SnO 2 was used as sensing material for gas sensor to detect n-butanol gas. The gas-sensing properties including gas response, selectivity, response-recovery time, repeatability, stability and dynamic response character were investigated carefully. It can be found that the response value of the sensor towards 100 ppm n-butanol gas was 303.49 at the low operating temperature of 160 °C. And the detection limit as low as 1 ppm. All results demonstrate the potential of using raspberry-like SnO 2 for n-butanol gas detection. At the same time, the possible formation mechanism and gas-sensing mechanism were also discussed. [ABSTRACT FROM AUTHOR]

High cycle fatigue and very high cycle fatigue properties of a surface-carburized CrNi steel were examined under axial loading with stress ratios of −1 and 0. The positive stress ratio overcomes the effect of carburized layer and promotes crack initiation from the carburized layer. The morphology of fine granular area (FGA) is more distinct under the negative stress ratio with more obvious crack closure effect. Two models concerning the inclusion-fisheye failure and the inclusion-FGA-fisheye failure are proposed. The predicted fatigue lives based on the concept of crack initiation are in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles with the different Cd doping contents were prepared by with a surfactant-mediated method in this paper. The effects of Cd doping on the gas sensing properties of the ZnO nanoparticles were studied. The morphology and microstructure of as-prepared samples were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM), respectively. The results reveal that all the products are the high crystalline hexagonal wurtzite ZnO crystal structure. The gas-sensing characteristics of the Cd doped ZnO nanoparticles for volatile organic compounds (VOCs) were investigated. At its optimal operation temperature of 300 °C, the sensing properties of the Cd doped ZnO nanoparticles for n-butanol gas exhibit a high-performance gas sensing performances including high gas response, good selectivity, response/recovery time, and repeatability as well as stability. Especially, its response reaches 130 for 100 ppm n-butanol of ZnO nanoparticles with 2.5% Cd doping. Those values demonstrate the potential of using as-prepared Cd doped ZnO nanoparticles for n-butanol gas detection, making them to be promising candidates for practical detectors to n-butanol gas. Apart from these, the mechanism related to the advanced properties was also investigated and presented. [ABSTRACT FROM AUTHOR]

SnO 2 -composite Pd nanoparticles (0, 2.5, 7.5, 10 mol% Pd loading) were synthesized via solvothermal method, followed by calcination. The structure, morphology, chemical state and specific surface area of the Pd-SnO 2 composite were analyzed with X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N 2 physisorption, respectively. It is found that the composites consist of large amount of SnO 2 microspheres with average diameters up to hundreds of nanometers, and the microspheres are assembled by numerous nanoparticles with average sizes of about 8 nm. To demonstrate their potential application, gas sensors based on the as-synthesized Pd-SnO 2 composites were fabricated to test their sensing performances. The 10 mol% Pd-SnO 2 composite shows an excellent sensing response towards different concentrations of hydrogen at 200 °C. The highest sensing response is up to 315.34 for 3000 ppm hydrogen with a fast response-recovery time (4 s/10 s), which is over 8 times higher than that of pristine SnO 2 , and the lowest detection limit is down to 10 ppm. More significantly, it presents excellent selectivity and stability for hydrogen. The improved sensing response characteristics of the composite could be attributed to the chemical sensitization and electronic sensitization of Pd catalyst. [ABSTRACT FROM AUTHOR]

Tin oxide microspheres were successfully obtained through a facile hydrothermal method without any polymer templates or surfactant. The as-synthesized SnO 2 microspheres are composed of large amount of small spheres with average diameters of about 250 nm, and every small sphere consists of numerous primary nanocrystallites with average sizes of about 8 nm. The resultant product was used as sensing material for gas sensor to detect the formaldehyde (HCHO) gas. The gas response, response and recovery time, selectivity and stability were carefully studied. It was found that the response value of the sensor to 100 ppm HCHO was 38.3 at the operating temperature of 200 °C. The gas sensor based on SnO 2 microspheres has excellent gas response, good response-recovery properties, linear dependence, repeatability and selectivity, making it to be a promising candidate for practical detectors for HCHO. [ABSTRACT FROM AUTHOR]

Nanoporous titanium dioxide was synthesized by a hydrothermal method without using of surfactant or template. The structure, morphology, surface chemical states and specific surface area were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N 2 adsorption-desorption isotherms, respectively. The as-synthesized products are anatase-TiO 2 with small grain size (about 12.27 nm) and high surface area (147.17 m 2 g −1 ). The as-synthesized porous TiO 2 powder was used to fabricate indirect-heating gas sensor whose gas-sensing characteristics toward acetone were investigated. At its optimal operation temperature, the sensor possesses a good sensitivity, selectivity, linear dependence, low detection limitation, and response/recovery, repeatability as well as long-term stability. Especially for the high sensitivity and fast response/recovery, its response reaches 25.97 for 500 ppm acetone, which is several times higher that of the reported TiO 2 -based sensors. The response and recovery times are only 13 and 8 s, respectively. Those values demonstrate the potential of using as-synthesized TiO 2 for acetone gas detection, particularly in the dynamic monitoring. Apart from these, the mechanism related to the advanced properties was also investigated and presented. [ABSTRACT FROM AUTHOR]

Hydrazine electro-oxidation takes an important role in direct hydrazine fuel cells (DHFCs) and hydrazine electrochemical sensor, but the high cost of precious metal electrode hinders the practical applications of hydrazine electro-oxidation. In this study, an inexpensive 3D electrode of Ni 3 S 2 @Ni foam was obtained through a hydrothermal condition using sodium sulfide as corrodent and Ni foam as both substrate and Ni source. The formation mechanism of this Ni 3 S 2 layer was studied through a process analysis based on physical chemistry with assistant of the results from characterizations. The obtained Ni 3 S 2 @Ni foam was used as electrode to test its hydrazine electro-oxidation properties in terms of DHFCs and electrochemical sensor. It is found Ni 3 S 2 @Ni foam possesses the ability to electro-oxidize hydrazine and Ni 3 S 2 layer leads to increased activity including lower onset potential and higher current. In the aspect of hydrazine electrochemical sensor, the fabricated Ni 3 S 2 layer leads to increased sensitivity and dynamic response property. The results indicate that as-prepared Ni 3 S 2 @Ni foam possesses a potential for practical application in hydrazine electro-oxidation, and Ni 3 S 2 is a very promising substitute material for noble metals in hydrazine electro-oxidation. At the same time, with the characterization of the as-prepared Ni 3 S 2 @Ni foam electrode on structure, morphology and surface chemical states, the mechanism of the corrosion method as well as enhanced properties were investigated. [ABSTRACT FROM AUTHOR]

Meso- and macroporous coral-like Co 3 O 4 was synthesized via a facile self-sustained decomposition using the complexes of metallic salts and organics (metal-organic complexes). Porous Co 3 O 4 material was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectrum (XPS) to examine the morphology and microstructure to find out the cause. Co 3 O 4 with the meso- and macroporous structure consisting of nanoparticles has a coral-like shape with a size of tens of micrometers and exhibits the hierarchically porous morphology, in which the walls of the macropores contain smaller mesopores. The gas-sensing characteristics of the porous Co 3 O 4 for volatile organic compounds (VOCs) were investigated. The gas response to 1000 ppm n-butanol reaches a maximum of 27.7 at an operating temperature of 120 °C, and about five times of the Co 3 O 4 particles. The porous Co 3 O 4 also exhibits certain selectivity and response/recovery time. [ABSTRACT FROM AUTHOR]

• The interior microcrack growth in the maximum shear stress plane is observed in FIB milling. • Formation of facets is attributed to the pure slip where the facet plane is closed to 45°. • The crack growth rate within the IMZ is less than the magnitude of one Burger's vector. • A strength evaluation approach with facet-IMZ-fisheye induced failure is proposed. Very high cycle fatigue properties of titanium alloys under symmetrical and asymmetrical loads were experimentally examined to clarify the failure behavior. An inhomogeneous microstructure zone (IMZ) containing facets is observable. By focused ion beam testing, the interior micro-crack extends along the maximum shear stress plane and the facet plane is about 45°. By the modeling of growth rate and the definition of controlling line, a strength evaluation approach with the failure behavior was well proposed. This reflects that the micro-crack growth rate in IMZ stage is below one Burger's vector. [ABSTRACT FROM AUTHOR]