Biography:

In the past Xiaoguang Wang has collaborated on articles with HIDEHARU FUKUNAGA and Pascale Roesch. One of their most recent publications is WS10d3 - PREPARATION AND PROPERTIES OF INTERMETALLICS DISTRIBUTED MATRIX COMPOSITES BY REACTION SQUEEZE CASTING. Which was published in journal .

More information about Xiaoguang Wang research including statistics on their citations can be found on their Copernicus Academic profile page.

Xiaoguang Wang's Articles: (24)

WS10d3 - PREPARATION AND PROPERTIES OF INTERMETALLICS DISTRIBUTED MATRIX COMPOSITES BY REACTION SQUEEZE CASTING

ABSTRACTUsing TiO2 anatase whiskers as the reinforcement and aluminium as the matrix material, the reaction squeeze casting has been carried out to make the intermetallics distributed matrix composites. Fabricated RSC samples showed α-Al2O3 +TiAl or A1 + α-Al2O3 + TiAl + TiAl3+TiO2 presented in the microstructure, and their hardnesses were Hv 1050 to 70. The reactions at the temperature during RSC process were favored by thermodynamics and were exothermic reaction. The differential scanning calorimeter curve showed the reaction initiated explosively, achieved 1100°C, and continued for several seconds in the first period. At some RSC process conditions, the reactions proceeded uncompletely and the stratified structures were formed, even the calculation of the complete reactions leads to a Vf of 47% TiO2 for α-Al2O3+TiAl or of 32% for α-Al2O3+TiAl3 formations.

Moduli space of cubic Newton maps

AbstractIn this article, we study the topology and bifurcations of the moduli space M3 of cubic Newton maps. It's a subspace of the moduli space of cubic rational maps, carrying the Riemann orbifold structure (Cˆ,(2,3,∞)). We prove two results:• The boundary of the unique unbounded hyperbolic component is a Jordan arc and the boundaries of all other hyperbolic components are Jordan curves;• The Head's angle map is surjective and monotone. The fibers of this map are characterized completely.The first result is a moduli space analogue of the first author's dynamical regularity theorem [37]. The second result confirms a conjecture of Tan Lei.

A comparative study of elemental additives (Ni, Co and Ag) on electrocatalytic activity improvement of PdSn-based catalysts for ethanol and formic acid electro-oxidation

AbstractIn this study, we have synthesized a series of carbon supported PdSn(molar ratio 1:1), PdSnAg(2:2:1), PdSnNi(2:2:1) and PdSnCo(2:2:1) catalysts by a borohydride reduction method. These catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and chronoamperometry (CA). As compared with PdSn/C, the trimetallic catalysts show a significant activity enhancement for ethanol and formic acid electro-oxidation. Moreover, the PdSnAg/C catalyst exhibits the highest activity together with much better stability. The activity enhancement of PdSnAg/C can be rationalized by the synergistic effect of Pd-SnO2-Ag clusters on the superficial surface of catalyst, such as bi-functional mechanism, superior electronic structure, excellent electric conductivity, etc. In addition, both ethanol and formic acid electro-oxidation reactions on the PdSnAg/C catalyst are diffusion-controlled and represent good linear correlation with ethanol and formic acid concentrations.

Electrochemical activated PtAuCu alloy nanoparticle catalysts for formic acid, methanol and ethanol electro-oxidation

AbstractThrough synthesizing a series of carbon supported ternary PtAuCu nanoparticle catalysts with the varied Cu content followed by subsequently electro-chemical activation treatment, highly active Pt-Au-rich nanoparticle catalysts have successfully been acquired in the present paper. The as-synthesized and activated catalysts were characterized using X-ray diffraction (XRD), transmission electron spectroscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and chronoamperometry (CA). The results show that the electrochemical activation process has a strongly interrelationship with the compositional ratio between Pt/Au and Cu. The higher the Cu content is in the precursor, the lower the residual buried-underneath Cu atoms retain after the activation. Among the catalysts, the activated Pt10Au10Cu80/C exhibits the best catalytic performance for the electro-oxidation of commonly-targeted small organic molecule fuels including formic acid, methanol and ethanol in acid circumstance. The catalytic activity enhancement mechanism based upon the electrochemical activation process as well as induced possible synergistic effect from elemental interactions was also discussed.

Sol–gel synthesis and optical properties of size controlled Indium Arsenide nanocrystals embedded in silica glasses

AbstractIII–V semiconductor Indium Arsenide (InAs) nanocrystals embedded in silica glasses was synthesized by combining the sol–gel process and heat treatment in H2 gas. The size of InAs nanocrystals can be easily controlled via changing the In and As content in the starting materials and the heating temperature in a H2 gas atmosphere. Absorption measurements indicate a blue shift in energy with a reduction on the In and As content in the SiO2 gel glasses as a result of quantum confinement effects. A near-infrared photoluminescence with peak at 3.40 μm was observed at 6 K under 514.5 nm Ar+ laser excitation from InAs nanocrystals embedded in the silica gel glasses.

Research papersCharacterization of horizontal transmissivity anisotropy using cross-hole slug tests

Highlights•A new method for characterizing horizontal transmissivity anisotropy using cross-hole slug tests is proposed.•The method is validated by a numerical example and against Papadopulos’ method based on cross-hole pumping tests.•Effects of heterogeneity, measurement scale and medium connectivity on the tensor analysis were discussed.

A generated approximation related to Gosper’s formula and Ramanujan’s formula

AbstractIn this paper, based on Gosper’s formula and Ramanujan’s formula, a generated approximation of the factorial function and some inequalities for the gamma function are established. Finally, for demonstrating the superiority of our new series over the classical Stirling’s series, some numerical computations are given.

Coherence and squeezing in superpositions of spin coherent states

AbstractWe consider the superpositions of spin coherent states and study the coherence properties and spin squeezing in these states. The spin squeezing is examined using a new version of spectroscopic squeezing criteria. The results show that the antibuching effect can be enhanced and spin squeezing can be generated in the superpositions of two spin coherent states.

A new and direct route to 3-fluoromethyl substituted pyrazol-4-acrylates via Pd-catalyzed C–H activation

AbstractDirect C4–H activation of 3-fluoromethyl pyrazoles followed by an oxidative coupling with acrylates, which is perhaps the most direct method for the synthesis of 3-fluoromethyl substituted pyrazol-4-acrylates of biological interest, remains challenging. Here, the first example of the straightforward olefination via Pd-catalyzed C4–H activation of both C3–CF3 and C3–CF2H substituted pyrazoles is reported. The reaction of various C3–CF3 substituted pyrazoles with acrylates proceeds smoothly in the presence of Pd(OAc)2 and Ag2CO3, whereas olefination of C3–CF2H substituted pyrazoles requires the addition of benzoquinone. A further computational study reveals that reactivity of the pyrazolyl substrates employed are strongly impacted by the substituents of different nature on their C1 or C5 position, which is in good agreement with the experimental data.

AChE inhibition: One dominant factor for swimming behavior changes of Daphnia magna under DDVP exposure

Highlights•AChE activity inhibition is one dominant factor for behavior changes of D. magna under DDVP exposure.•Swimming behavior shows a positive relationship with AChE activity inhibition.•Adjustment in behavioral responses is important for D. magna in different exposure.

Aluminum chloride induces neuroinflammation, loss of neuronal dendritic spine and cognition impairment in developing rat

Highlights•AlCl3 caused neuroinflammation in hippocampus.•AlCl3 caused loss of dendritic spine in hippocampus.•Loss of spine may result in cognition impairment of AlCl3-treated rats.

Modelling potential conservation easement locations using physical and socio-economic factors: A case-study from south-east Michigan

Highlights•We examine the relationships of two types of conservation easements.•We project similar potential locations based on only physical landscape.•We compare it to both physical and social landscape by adapting the ecological model.•There is little difference for environmental conservation easement.•There is substantially different distribution for open space conservation easement.

Experimental and theoretical analysis of Al3+ complexation with ADP and ATP

AbstractAl3+ ion is known to interact significantly with a number of biochemical systems, and has been linked to a number of human diseases. Owing to the affinity of Al3+ for phosphate oxygens, much recent interest has focused on complexes that Al3+ can form with nucleoside di- and tri-phosphates. ATP, for example, may serve as a major intracellular chelator of Al3+. While potentiometric titrations have provided a wealth of information on the nature of various nucleoside phosphate-Al3+ species which can exist in solution under a given set of conditions, this approach alone cannot distinguish between all possible complexes that may exist, especially where dimers or high multimeric forms are present. In this paper, 500 MHz 1H NMR data collected on samples that vary in the nature of the nucleoside phosphate (i.e., either ADP or ATP), the concentration of nucleoside phosphate (from 0.5 to 10 mM), the pH (from 5.0 to 7.0), and the ratio of total Al3+ to total nucleoside phosphate (from 0.455 to 1.0) were simultaneously analyzed by a nonlinear least squares procedure, providing evidence for several Al3+-nucleoside phosphate complexes along with the associated formation constants (all fits being characterized by apparent σ values < 0.05 in mole fraction units). In neutral solutions the main species present with equal amounts of Al3+ and nucleotide are HOM2L2 and ML, while with excess ligand ML2 complexes predominate. Bases in the ML2 complexes are about 87% stacked.

Nonparametric estimation of the ROC curve based on the Bernstein polynomial☆

AbstractThe receiver operating characteristic (ROC) curve is a graphical representation of the relationship between false positive and true positive rates. It is a widely used statistical tool for describing the accuracy of a diagnostic test. In this paper we adopt Bernstein polynomials to construct the ROC curve estimator. The consistency rate of this estimator is studied. We also obtain explicit expressions for the asymptotic bias and variance and show the improvement of the asymptotic mean squared error compared to that of the classical empirical ROC estimator. Furthermore, the weak convergence of the Bernstein ROC process is established. Simulation studies are conducted to compare our proposed estimator with other popular nonparametric ROC estimators. Finally, the proposed method is illustrated by application to a real data set.

Entanglement properties in (12,1) mixed-spin Heisenberg systems

AbstractBy using the concept of negativity, we investigate entanglement in (12,1) mixed-spin Heisenberg systems. We obtain the analytical results of entanglement in small isotropic Heisenberg clusters with only nearest-neighbor (NN) interactions up to four spins and in the four-spin Heisenberg model with both NN and next-nearest-neighbor (NNN) interactions. For more spins, we numerically study effects of temperature, magnetic fields, and NNN interactions on entanglement. We study in detail the threshold value of the temperature, after which the negativity vanishes.

Entanglement oscillations in open Heisenberg chains

AbstractWe study pairwise entanglements in spin-half and spin-one Heisenberg chains with an open boundary condition, respectively. We find out that the ground-state and the first-excited-state entanglements are equal for the three-site spin-one chain. When the number of sites L>3, the concurrences and negativities display oscillatory behaviors, and the oscillations of the ground-state and the first-excited-state entanglements are out of phase or in phase.

Entanglement, purity and fidelity in the anisotropy (1/2,1) mixed-spin system

AbstractWe study entanglement, purity and fidelity in the anisotropy (1/2,1) mixed-spin Heisenberg chain. We find that negativity, as a measure of entanglement, displays a dip at the SU(2) isotropic point of the system, which is in contrast to the peak appearance of concurrence in the spin-1/2 XXZ chain. Moreover, at the isotropic point, purity gives a minimum, while the mixed-state fidelity susceptibility emerges a maximum.

From water reduction to oxidation: Janus Co-Ni-P nanowires as high-efficiency and ultrastable electrocatalysts for over 3000 h water splitting

Highlights•Co-Ni-P nanowire arrays are grown on Ni foam forming an integrated electrode.•The electrode can catalyze both H2 and O2 evolution showing bifunctionality.•An electrolyzer is assembled using two symmetrical integrated electrodes.•The electrolyzer shows high energy efficiency for overall water splitting.•The electrolyzer can sustain 3175 h at 100 mA cm−2 without degradation.

Emission turn-on chemosensing platforms for mercury detection based on a secondary energy transfer from up-conversion nanocrystals to rhodamine-based probes

Highlights•Two Hg(II) sensing platforms with chemosensors derived from rhodamine were reported.•NaYF4:Yb3+/Er3+ nanocrystals were used as excitation host to improve photostability.•A simple recognition mechanism with binding stoichiometry of 1:1 was confirmed.•Good selectivity, linear working curves and high photostability were demonstrated.

High activity of novel nanoporous Pd–Au catalyst for methanol electro-oxidation in alkaline media

Highlights•Nanoporous PdAu catalyst can be fabricated by dealloying of AlPdAu ternary alloy.•Nanoporous PdAu catalyst exhibits enhanced activity for methanol electro-oxidation.•Alloying Au facilitates CO-like species oxidation and active Pd sites recovery.

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