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Visible light has shown to greatly enhance the activity of iron-doped semiconductor catalyst in a Fenton reaction system, however, the mechanism for this activity enhancement remains unclear. This work attempts to reveal the origin of this visible light driven activity enhancement by studying the iron doped semiconductor catalyst Fe/g-C3N4 in both photo-Fenton and dark Fenton reactions. Through analysis of XPS spectra of catalyst, it is found that Fe2+/Fe3+ ratio for Fe/g-C3N4 catalyst remains unchanged and sustained during the photo-Fenton reaction cycles. This is in direct contrast to the progressively decreased Fe2+/Fe3+ ratio observed in the dark Fenton reaction. It is clear that under visible light, Fe3+ is able to capture the photo-generated electrons from the semiconductor and revert back to Fe2+, thus sustain the catalytic activity during the photo-Fenton reaction. This new mechanistic insight will guide the future design and optimization of high performance catalysts by immobilizing transition metal ions in semiconductors for advanced oxidation processes.

The development of high-efficiency photocatalysts is of great importance to realize robust solar-driven CO₂ conversion; however, the low carrier separation efficiency and poor light absorption ability usually limit the performance of the photocatalysts. Herein, a hollow In₂S₃/polymeric carbon nitride (IS/CN) heterojunction was prepared via electrostatic self-assembly and in situ sulfidation under solvothermal conditions. The intimate interfacial contact between the IS and CN facilitates the construction of an effective heterojunction, as demonstrated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The optimized IS/CN-5 sample exhibits a high CO evolution rate of 483.4 μmol g–¹ h–¹, which is 99 and 6 times as high as that of IS and CN, respectively. The improved charge separation and transfer efficiency, the hollow nanotube structure, and the enhanced CO₂ adsorption ability are the reasons for the excellent photocatalytic activity. Besides, a possible photocatalytic mechanism of CO₂ reduction by the IS/CN heterojunction was proposed on the basis of the band structures. This work provides an effective and facile strategy to construct hollow semiconductor heterojunctions for photocatalytic applications.

In this work, we present an in situ method to probe the evolution of photoelectrochemically driven surface oxidation on photoanodes during active operation in aqueous solutions. A standard solution of K4Fe(CN)6-KPi was utilized to benchmark the photocurrent and assess progressive surface oxidation on Ta3N5 in various oxidizing solutions. In this manner, a proportional increase in the surface oxygen concentration was detected with respect to oxidation time and further correlated with a continuous decline in the photocurrent. To discern how surface oxidation alters the photocurrent, we experimentally and theoretically explored its impact on the surface carrier recombination and the interfacial hole transfer rates. Our results indicate that the sluggish photocurrent demonstrated by oxidized Ta3N5 arises because of changes in both rates. In particular, the results suggest that the N-O replacement present on the Ta3N5 surface primarily increases the carrier recombination rate near the surface and to a lesser degree reduces the interfacial hole transfer rate. More generally, this methodology is expected to further our understanding of surface oxidation atop other nonoxide semiconductor photoelectrodes and its impact on their operation.

Early diagnosis is critical for the prevention and control of the coronavirus disease 2019 (COVID-19). We attempted to apply a protocol using teleultrasound, which is supported by the 5G network, to explore the feasibility of solving the problem of early imaging assessment of COVID-19. Four male patients with confirmed or suspected COVID-19 were hospitalized in isolation wards in two different cities. Ultrasound specialists, located in two other different cities, carried out the robot-assisted teleultrasound and remote consultation in order to settle the problem of early cardiopulmonary evaluation. Lung ultrasound, brief echocardiography, and blood volume assessment were performed. Whenever difficulties of remote manipulation and diagnosis occurred, the alternative examination was repeated by a specialist from another city, and in sequence, remote consultation was conducted immediately to meet the consensus. The ultrasound specialists successfully completed the telerobotic ultrasound. Lung ultrasound indicated signs of pneumonia with varying degrees in all cases and mild pleural effusion in one case. No abnormalities of cardiac structure and function and blood volume were detected. Remote consultation on the issue of manipulation practice, and the diagnosis in one case was conducted. The cardiopulmonary information was delivered to the frontline clinicians immediately for further treatment. The practice of teleultrasound protocol makes early diagnosis and repeated assessment available in the isolation ward. Ultrasound specialists can be protected from infection, and personal protective equipment can be spared. Quality control can be ensured by remote consultations among doctors. This protocol is worth consideration as a feasible strategy for early imaging assessment in the COVID-19 pandemic.

Magnetic anomaly detection is an effective method for detecting ferromagnetic targets. The practical application of target detection by measuring the magnetic gradient has been confirmed in many studies, and its suppression of background noise has been widely recognized. However, the variation of the unidirectional magnetic field gradient is very small in a short distance, and the amplitude of the signal is also affected by the direction of the target’s magnetic moment and the shaking of the sensor platform itself. These make it difficult to extract the signal from complex background interference. In order to solve these problems, this paper is devoted to use the variation of three axial magnetic gradients in the geomagnetic coordinate system caused by the presence of magnetic target (we call it full magnetic gradient) to construct the magnetic anomaly characteristic of the target. A set of orthonormal basis functions is further derived to linearly describe this characteristic, which improves the signal-to-noise ratio (SNR) of the signal from the perspective of signal energy. The present work main contribution is to propose a full magnetic gradient orthonormal basis function (FMG-OBF) method to effectively characterize magnetic anomaly of magnetic targets. Compared with the traditional one-direction magnetic gradient orthonormal basis function method, the SNR of this method is greatly improved, and it is not affected by a change in the target magnetic moment’s direction nor by the shaking of the sensor carrier platform. Therefore, it has great value in the practical application of aeromagnetic detection.

Heterogeneous catalysts with ultra-small clusters and atomically dispersed (USCAD) active sites have gained increasing attention in recent years. However, developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging. Here, through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine (MA), porous alveolate Fe/g-C3N4 catalysts with high-density (Fe loading up to 17.7 wt%) and increased USCAD Fe sites were synthesized. The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts; the S species act as a “sacrificial carrier” to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis. The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts, due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure. This S-assisted method exhibits good feasibility in a large variety of S species (thiourea, S powder, and NH4SCN) and Fe salts, providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.

Low charge separation efficiency is the critical limitation for solar-driven CO2 conversion into chemicals fuels. Accelerating charge transfer in the interface of photocatalysts is an intriguing approach to suppress charge recombination. Herein, Co2+ doped 0D/2D TiO2 quantum dots confined in graphitic carbon nitride (CoTiCN) heterostructure was prepared by in-situ pyrolysis of MOFs and urea. Co2+ serves as the bridge of linking 0D TiO2 and 2D g-C3N4 in the interface, and consequently accelerates charge transfer in the interface from 2D g-C3N4 to 0D TiO2. As a result, CO evolution rate for photocatalytic CO2 reduction reached 290 μmol g−1 h−1, much higher than those of pure g-C3N4 and TiO2/g-C3N4. In addition, photocatalytic mechanism study indicates that [Co(bpy)3]Cl2 in the system functions as cocatalyst without any photocatalytic activity under visible light irradiation. Electron transfer occurs from heterogeneous photocatalyst to [Co(bpy)3]Cl2, which acts as the electron transporter as active sites to catalyze CO2 reduction into CO. This work provides an insight into the design of metal doped 0D/2D material towards visible light driven CO2 reduction from the viewpoint of promoting charge transfer in the interface and the understanding of the photocatalytic mechanism of cocatalyst in system.

Two-dimensional graphitic carbon nitride (g-C3N4) has been widely explored as a promising photocatalyst for solar CO2 conversion. However, rapid charge recombination and low visible-light utilization are severely detrimental to photocatalytic CO2 conversion. Zero-dimensional/two-dimensional (0D/2D) heterostructures are considered the promising materials with size tunability and enhanced charge separation efficiency for photocatalysis. Herein, a 0D/2D heterostructure of oxygen vacancy-rich TiO2 quantum dots confined in g-C3N4 nanosheets (TiO2-x/g-C3N4) was prepared by in-situ pyrolysis of NH2-MIL-125 (Ti) and melamine. Charge dynamics analysis by time-resolved photoluminescence (tr-PL) and femtosecond and nanosecond pump-probed transient absorption (TA) spectra revealed that charges transfer occured from 2D-g-C3N4 to 0D-TiO2 at an ultrafast subpicosecond time scale (

Fundamental photocatalytic limitations of solar CO2 reduction remain due to low efficiency, serious charge recombination, and short lifetime of catalysts. Herein, two-dimensional graphitic carbon nitride nanosheets with nitrogen vacancies (g-C3 Nx ) located at both three-coordinate N atoms and uncondensed terminal NHx species were prepared by one-step tartaric acid-assistant thermal polymerization of dicyandiamide. Transient absorption spectra revealed that the defects in g-C3 N4 act as trapped states of charges to result in prolonged lifetimes of photoexcited charge carriers. Time-resolved photoluminescence spectroscopy revealed that the faster decay of charges is due to the decreased interlayer stacking distance in g-C3 Nx in favor of hopping transition and mobility of charge carriers to the surface of the material. Owing to the synergic virtues of strong visible-light absorption, large surface area, and efficient charge separation, the g-C3 Nx nanosheets with negligible loss after 15 h of photocatalysis exhibited a CO evolution rate of 56.9 μmol g-1 h-1 under visible-light irradiation, which is roughly eight times higher than that of pristine g-C3 N4 . This work presents the role of defects in modulating light absorption and charge separation, which opens an avenue to robust solar-energy conversion performance.

In this work, we proposed a facile and green method involving just two steps of dispersion and annealing to in-situ synthesize TiN/C composite materials. First, the nitrogen and titanium sources were combined by a complexing agent in the dispersion process, and then TiN/C composite materials were obtained by annealing the solid precursors from centrifuging the above solution in nitrogen atmosphere. High-density TiN nanoparticles with the size of ∼10 nm are dispersed uniformly on carbon matrix, and the composite has a high specific surface area up to 148 m2/g. When used as supercapacitor electrode materials, the composite exhibits relatively high specific capacitance of 159.0 F/g at 0.5 A/g, and good rate performance with specific capacitance of 96.0 F/g at 20 A/g. The current facile method could be a promising strategy for the low-cost and large-scale synthesis of metal nitride/carbon composite materials.

4f chemistry studies the chemical bonding characteristics of fifteen lanthanide (Ln) elements in the periodic table and their wide applications in materials sciences and engineering, which forms the scientific fundamentals of VI periodic elements in the periodic table of elements. Orbital hybridization modes of Ln elements clarify their chemical bonding nature in all reaction systems. Wide coordination number (CN) option, ranging from 2 to 16, is the reason why Ln elements are the treasure of new materials, therefore, searching for novel materials may be well carried out via the rational design of coordination environment of central Ln cations to stabilize their variable energy states. Balance utilization of Ln elements is dependent on their coordination architecture in the crystallographic frame, Ln elements can be replaced by non-Ln elements when CN

In this study, the nondeterministic structural responses of functionally graded material (FGM) plates under static loads with uncertain material property is investigated. The considered spatially dependent uncertainties are modelled as random fields with Gaussian distribution. A novel spectral stochastic isogeometric analysis (SSIGA) framework is proposed for such uncertainty quantification through the first-order shear deformation theory. Within the SSIGA framework, the non-uniform rational B-spline (NURBS) is adopted for both the geometry modelling of the random fields of the uncertain material properties and random field discretization through the Karhunen-Loeve (K-L) expansion. Such new feature provides an effective and practically applicable random field modelling technique, especially for uncertain parameters over complex physical domains. The polynomial chaos expansion (PCE) is employed for estimating the statistical characteristics (e.g., mean and standard deviation) of any concerned structural responses (e.g., displacement and stress). By further implementing various statistical inference techniques, the probability density functions (PDF) and cumulative distribution functions (CDF) of structural responses can be established to determine both serviceability and strength limits of FGM plate. Two numerical examples are thoroughly investigated to illustrate the applicability, effectiveness and efficiency of the proposed computational approach.

Ultra-small metal clusters have attracted great attention owing to their superior catalytic performance and extensive application in heterogeneous catalysis. However, the synthesis of high-density metal clusters is very challenging due to their facile aggregation. Herein, one-step pyrolysis was used to synthesize ultra-small clusters and single-atom Fe sites embedded in graphitic carbon nitride with high density (iron loading up to 18.2 wt %), evidenced by high-angle annular dark field-scanning transmission electron microscopy, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and 57Fe Mossbauer spectroscopy. The catalysts exhibit enhanced activity and stability in degrading various organic samples in advanced oxidation processes. The drastically increased metal site density and stability provide useful insights into the design and synthesis of cluster catalysts for practical application in catalytic oxidation reactions.

Titanium based MOF materials NH2-MIL-125 was synthesized through solvothermal method. By increasing the concentration of the reactants, the morphology of NH2-MIL-125 can be controlled from circular plate to special polyhedron. Meanwhile, the polyhedron can be modulated from octahedron to rhombic dodecahedron through changing the titanium ester of the reactants from tetraethyl titanate to tetrabutyl titanate. This is the first time to obtain NH2-MIL-125 with rhombic dodecahedron morphology. The test of acetic acid as additive on morphology changes shows that the adsorption of additives on special facets shows a more significant impact on the morphology formation. The morphology control of NH2-MIL-125 based on the modulation of the type of titanium ester, reactants concentration, and the added acetic acid concentration were detailed exhibited and explained.

Magnetic Fe3O4/CeO2 composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO2 as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N2 adsorption/desorption analysis. The mesoporous Fe3O4/CeO2 composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe3O4/CeO2 was much higher than that of irregular porous Fe3O4/CeO2. The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO2, high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce3+ content and the synergistic effect between Fe and Ce. The mesoporous Fe3O4/CeO2 composite presented low metal leaching (iron 0.22 mg L−1 and cerium 0.63 mg L−1), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.

The effect of monocarboxylic acids on synthesizing NH2-MIL-125 is systematically studied for the first time in this work, and the fantastic results are discussed in detail. We found that a small molecular acid (acetic acid, thioglycolic acid) mostly affects the morphology changes of NH2-MIL-125, while the pseudolinker acid (p-toluylic acid, benzoic acid) has a significantly impact on the crystal size on account of the nucleation and the crystal growth rates. Ar sorption measurement and transmission electron microscopy characterization show that samples synthesized with pseudolinker acid as additives have a hierarchical structure owing to the internal defects or caves formed in the crystal. These samples also show an excellent performance for the removal of organic pollutants by the combined effects of adsorption and photodegradation.

A spectral stochastic isogeometric analysis (SSIGA) scheme is proposed for the stochastic linear stability analysis of plate with uncertain material properties . Within the proposed SSIGA scheme, the first-order shear deformation theory of plate is adopted for modelling the kinematic relationship . Both homogeneous and functionally graded material (FGM) models can be incorporated. The considered spatially dependent uncertainties (i.e., Young’s modulus and Poisson’s ratio) are modelled as random fields with Gaussian and lognormal distributions , and the spatially independent uncertainty (i.e., gradient index of FGM) is modelled as random variable . The generalized isogeometric basis function is adopted for both the random field geometry representation and random field discretization through the Karhunen–Loeve (K–L) expansion. An extended support vector regression (X-SVR) with a new generalized Gegenbauer polynomial kernel is developed to model the nonlinear relationship between the structural uncertainties and the buckling load. By further implementing various nonparametric statistical inference methods, the mean, standard deviation, probability density function (PDF), and cumulative distribution function (CDF) of the buckling load can be effectively established to determine the strength limit of the plate. The accuracy, efficiency, and applicability of the proposed approach are illustrated through two numerical examples.

A novel spectral stochastic isogeometric analysis (SSIGA) is proposed for the free vibration analysis of engineering structures involving uncertainties. The proposed SSIGA framework treats the stochastic free vibration problem as a stochastic generalized eigenvalue problem . The stochastic Young’s modulus and material density of the structure are modelled as random fields with Gaussian and non-Gaussian distributions. The basis functions, the non-uniform rational B-spline (NURBS) and T-spline, within Computer Aided Design (CAD) system are adopted within the SSIGA, which can eliminate geometric errors between design model and uncertainty analysis model. The arbitrary polynomial chaos (aPC) expansion is implemented to investigate the stochastic responses (i.e. eigenvalues and eigenvectors) of the structure. A Galerkin-based method is freshly proposed to solve the stochastic generalized eigenvalue problems. The statistical moments, probability density function (PDF) and cumulative distribution function (CDF) of the eigenvalues can be effectively obtained. Two numerical examples with irregular geometries are investigated to illustrate the applicability, accuracy and efficiency of the proposed SSIGA for free vibration analysis of engineering structures.

In this work, a facile polyvinylpyrrolidone (PVP) assisted solvothermal route using mixed solvents was reported to synthesize uniform quaternary chalcogenide Cu2FeSnS4 (CFTS) particles. PVP played a crucial role in tuning the shape and size of the resulted CFTS particles. Without PVP irregular shaped CFTS particles were obtained, however, quasi-spherical CFTS particles were produced by addition of PVP. The average particle sizes of particles were in the range of ~ 360 to ~ 230 nm. Moreover, the photodegradation of Rhodamine-B (RhB) with CFTS particles under visible light was investigated and optimized in terms of PVP concentration, catalyst dosage, dye concentration and pH of the solution. The quenching experiments for reactive species indicates that both hydroxyl and superoxide radicals play roles in the photodegradation. The stability of the as-prepared CFTS particles was demonstrated by reusing it in five consecutive degradation cycles.

Surface engineering is an efficient way to enhance photoabsorption, promote charge separation and boost photocatalysis. Herein, sulfur-doped holey g-C3N4 nanosheets have been prepared through a universal self-templating approach with thiocyanuric acid as the single-precursor. By subtly controlling the feeding amount of precursor, the synthesized sulfur-doped holey g-C3N4 nanosheets exhibit excellent visible-light driven photocatalytic hydrogen production activity. The optimized catalyst presents a hydrogen evolution rate of 6225.4 μmol g−1h−1, with an apparent quantum yield of 10 % at 420 nm. Comprehensive characterizations and theoretical calculations suggest that the enhanced photocatalysis is attributed to the synergy of the enlarged surface area, the negatively-shifted conduction band, and the narrowed bandgap due to sulfur-doping and ultra-thin two-dimensional topology. This work highlights the importance of controlling the precursor dosage and inducing sulfur doping into the polymer, providing a promising and reliable strategy to simultaneously regulate the nanostructural and electronic structure of g-C3N4 for highly efficient photocatalysis.

Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe 2 O 3 /CuO and α-Fe 2 O 3 /CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe 3 O 4 /C/Cu was obtained by calcining the tartrate precursor under N 2 atmosphere at 500 °C. The Fe 3 O 4 /C/Cu composite possessed mesoporous structure and large surface area up to 133 m 2 g −1 . The Fenton catalytic performance of Fe 3 O 4 /C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe 3+ to Fe 2+ , which accelerated the Fe 3+ /Fe 2+ cycles and favored H 2 O 2 decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe 3+ and Cu 2+ , the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe 3 O 4 /C/Cu-H 2 O 2 system, and MB (100 mg L −1 ) was nearly removed within 60 min. The Fe 3 O 4 /C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile, cheap and green method for the synthesis of mesoporous composites as excellent Fenton-like catalysts, without any additional reductants or organic surfactants.

Ordered mesoporous graphitic carbon nitrides were prepared by directly condensing the uniform mixtures of melamine and KIT-6. After removal of the KIT-6 sacrificial template, the carbon nitrides were characterized with TEM, N2 physical adsorption, XRD, FT-IR, XPS, UV–vis and PL spectrometries, and tested for their RhB photocatalytic degradation activity. Together, these characterizations confirmed the as-prepared tunable mesoporous materials with enhanced charge separation efficiency and superior photocatalytic performance. Compared with a conventional bulk g-C3N4, ordered mesoporous g-C3N4 exhibits a larger specific surface area of 279.3 m2/g and a pore size distribution about 4.0 nm and 13.0 nm. Meanwhile, the reduced bandgap energy of 2.77 eV and lower photogenerated electron-hole pair recombination frequency were evidenced by UV–Vis and PL spectra. The RhB photocatalytic degradation activity maximizes with a mass ratio of KIT-6/melamine of 80% (KCN80), and the kinetic constant reaches 0.0760 min−1 which is 16 times higher than that of the bulk sample. Reusability of KCN80 was demonstrated by a lack of evident deactivation after three consecutive reaction periods. The direct condensation of the KIT-6 and melamine mixture does not require pre-casting of the precursor into the pore system of the templates. Owing to its high product yield, improved SBET, reduced bandgap energy and limited charge recombination, the facile-prepared ordered mesoporous g-C3N4 is a practical candidate for further modification.

With the assistance of inorganic salt, graphitic carbon nitride nanosheets were prepared with increased mesoporous surface area for promoting the photocatalytic performance compared with the one without. Series of photocatalysts with different mass ratio of NH4NO3/melamine were prepared and characterized by XRD, FT-IR, XPS, TEM, SEM, N2 physical adsorption, UV–vis and PL spectrometries. Photocatalytic degradation of RhB under visible light irradiation (λ>420 nm) was applied to evaluate catalytic properties. The catalytic activity maximizes at an intermediate NH4NO3/melamine ratio at 0.15, giving a maximum performance, RhB totally being degraded within 30 min and kinetic constant reaching 0.167 min−1 that is 4.5 times as high as that on BCN. The NH4NO3 assisted procedure is a facile, repeatable, environmental friendly, and efficient method for preparing g-C3N4 nanosheets with high photocatalytic performance.

Controlled synthesis of metal–organic frameworks (MOFs) in nanometer scale is highly desired for the optimization of properties and the extending of applications. In this work, Cu2O was used as additive for the first time in the synthesis of zirconium-based MOF UiO-66. We found that the amount of Cu2O additive had an important impact on downsizing the crystal size of UiO-66. Cu2O additive plays a role of rate controller of crystal growth of UiO-66 crystals by their competitive coordination behavior with the linker H2BDC between the [Zr–O] clusters. This generates a depleted H2BDC concentration for the coordination with the [Zr–O] clusters for constructing the UiO-66 framework, which favors the production of small crystals. As a result, well-dispersed nanometer scale UiO-66 crystals with mean crystal size of 40 nm can be easily synthesized by the addition of Cu2O. The as-synthesized nanometer scale UiO-66 crystals have a pure crystal structure with high crystallinity and superior porosity.

The cerium lanthanum composite 2CeO2–0.5La2O3 and rare earth Eu3+-doped composite phosphor powders were synthesized by a facile solution combustion reaction. X-ray diffraction patterns suggested Ce2LaO5.5 with a cubic fluorite structure which was the same as pure CeO2 except for the lattice parameter a. After the activator Eu3+ was doped to the composite, Eu3+ could locate at either La3+ or Ce4+ sites due to their close ionic radius. It was found that the lattice parameter a gradually decreased with increasing Eu concentration as Eu3+ occupied the La3+ site. However, the lattice parameter a obviously increased with increasing Eu concentration if Eu3+ occupied the Ce4+ site. All of the phosphor powders showed red-light emission from the dominant 5D0 → 7F2 characteristic transition of Eu3+ under excitation with 466 nm blue light. In particular, the system displayed remarkably enhanced luminescence as Eu3+ occupied the Ce4+ site rather than the La3+ site. The reason for this should be ascribed to the change in the amount of O vacancies in the host, which was confirmed from their Raman spectra. The results might be beneficial for the system potentially used in solid state lighting as well as other optoelectronic fields.

Partial isomorphic substitution of iron in an Fe(BDC)(DMF,F) metal organic framework by manganese, cobalt, and nickel has been described for the first time. Specifically, different amounts of Mn, Co and Ni have been incorporated into the Fe-based framework during a solvothermal crystallization procedure. Several characterization techniques, including XRD, FT-IR, SEM, EDS, TG, XPS and ICP-AES, strongly support the effective incorporation of Mn, Ni and Co into material frameworks. The catalytic performance of these materials was examined in liquid-phase degradation of phenol at 35 °C and near neutral pH of 6.2. The results show that the degradation efficiency can be evidently improved by the incorporation of Mn, while it can be inhibited by the incorporation of Ni. The incorporation of Co shows no remarkable influence on the degradation process. Moreover, the ratios of n(Fe)/n(Mn) in the bimetallic MOFs have a strong impact on the degradation process. The stability and reusability of these catalysts under mild conditions were also demonstrated in this study. This work illustrates the potential of bimetallic MOF structures in developing active heterogeneous catalysts for the degradation process of toxic compounds.

NH2-MIL-125(Ti) is a promising microporous MOF material which has potential applications in photocatalytic and catalytic oxidation reactions. In this work, a facile surfactant assistant synthetic method was employed to obtain hierarchical NH2-MIL-125 with the mesoporosity for photocatalytic degradation of organic dyes. The as-prepared NH2-MIL-125 showed excellent dye removal efficiency due to the combination of improved adsorption and photodegradation. Compared with the microporous NH2-MIL-125, the adsorption capacity of organic dyes increased 28% on hierarchical NH2-MIL-125 and the photodegradation rate approximately increased 2.4 times according to the structure with abundant mesopores and macropores. The morphology of hierarchical NH2-MIL-125 can also be modulated from tetragonal plates to truncated bipyramids and octahedrons, and the obtained catalyst shows similar enhanced photodegradation performance.

Magnetic porous Fe3O4/C/Cu2O composites were prepared by a simple two-step process. Porous Fe3O4/C was synthesized via calcining iron tartrate precursor and then Cu2O was composited with Fe3O4/C by a precipitation-reduction method. The as-prepared samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) elemental mapping. Results show that Fe3O4/C has porous nanorod structure, which is composed of numerous small nanoparticles of about 50nm. Fe3O4 and carbon are uniformly distributed in the Fe3O4/C/Cu2O composite and Cu2O is dispersed on the surface of Fe3O4/C. Fe3O4/C/Cu2O composite exhibits excellent photo-Fenton catalytic performance for the degradation of methylene blue (MB) under visible light irradiation and neutral pH conditions, and MB (100mg/L) could be almost completely removed within 60min. The composite shows good recyclability and could be conveniently separated by an applied magnetic field. These results demonstrate that the Fe3O4/C/Cu2O composite is a powerful Fenton-like catalyst for degradation of organic pollutants from wastewater.

The stochastic isogeometric analysis of linear elasticity problem is investigated in this study. The spectral stochastic analysis is introduced into isogeometric analysis (IGA), and a novel, yet robust, stochastic analysis framework, namely the spectral stochastic isogeometric analysis (SSIGA), is freshly proposed. Unlike traditional numerical solutions of the Karhunen–Loeve (K-L) expansion, the non-uniform rational B-spline (NURBS) and T-spline basis functions are employed within the proposed framework of SSIGA, so the random fields acting on a continuous physical medium with complex geometry can be handled in an appropriate, physically feasible and efficient fashion. The polynomials chaos expansion (PCE) is implemented to represent the stochastic structural response (e.g., displacement, strain and stress), such that all corresponding statistical characteristics (e.g., mean and standard deviation) can be robustly acquired. Furthermore, by utilizing the nonparametric statistical analysis, both probability density functions (PDFs) and cumulative distribution functions (CDFs) of concerned structural displacements and stresses can be effectively established. Within the framework of IGA, by meticulously implementing the concept of the higher-order k-refinement, the proposed SSIGA provides a more legitimate and efficient stochastic computational approach for modern engineering structures which are complicated by both spatially dependent uncertainties and complex geometries.

A rapid and sensitive LC-MS/MS method with good accuracy and precision was developed and validated for the pharmacokinetic study of quercetin-3-O-β-d-glucopyranosyl-7-O-β-d-gentiobioside (QGG) in Sprague-Dawley rats. Plasma samples were simply precipitated by methanol and then analyzed by LC-MS/MS. A Venusil® ASB C18 column (2.1 × 50 mm, i.d. 5 μm) was used for separation, with methanol-water (50:50, v/v) as the mobile phase at a flow rate of 300 μL/min. The optimized mass transition ion-pairs (m/z) for quantitation were 787.3/301.3 for QGG, and 725.3/293.3 for internal standard. The linear range was 7.32-1830 ng/mL with an average correlation coefficient of 0.9992, and the limit of quantification was 7.32 ng/mL. The intra- and inter-day precision and accuracy were less than ±15%. At low, medium and high quality control concentrations, the recovery and matrix effect of the analyte and IS were in the range of 89.06-92.43 and 88.58-97.62%, respectively. The method was applied for the pharmacokinetic study of QGG in Sprague-Dawley rats. Copyright © 2016 John Wiley & Sons, Ltd.

MnC2O4 precursor was prepared by a precipitation method, and then porous MnO@C composites were obtained by mixing MnC2O4 precursor with different amounts of glucose and sintering at different temperatures. The influences of carbon content and crystallinity on the electrochemical performance of MnO@C were investigated. Galvanostatic charge–discharge test results showed that the MnO@C sample “1.2,700” has the largest specific capacity among all samples, which can reach high specific discharge capacity of 1691 mAh g−1 at the current density of 100 mA g−1 after 200 cycles. Even at the high current density of 1600 mA g−1, a remarkable discharge capacity of ∼630 mAh g−1 can still be delivered, demonstrating a good rate capability. The excellent electrochemical performance can be ascribed to porous structure, good crystallinity and proper amount of carbon coating. This facile method can be applied to the large-scale synthesis of high performance transition metal oxide@carbon composite electrode materials.

A series of MIL-53(Fe)-type materials, Fe(BDC)(DMF,F), were prepared by using different ratios of n(FeCl3)/n(FeCl2), which have varied amounts of Fe(2+) in their frameworks. From FeCl3 to FeCl2, the structures of the synthesized samples transform from MIL-53(Fe) to Fe(BDC)(DMF,F). Along with this structure transformation, the crystal morphology goes through a striking change from a small irregular shape to a big triangular prism. This phenomenon indicates that the addition of FeCl2 is beneficial for the formation of a Fe(BDC)(DMF,F) structure. The catalytic activity of these iron-containing MOFs was tested in phenol degradation with hydrogen peroxide as an oxidant at near neutral pH and 35 °C. The degradation efficiency of these samples increases gradually from MIL-53(Fe) to Fe(BDC)(DMF,F). (57)Fe Mössbauer spectra reveal that Fe(2+) and Fe(3+) coexist in the Fe(BDC)(DMF,F) framework, and the highest amount of Fe(2+) in the sample prepared with mixed FeCl3 and FeCl2 is 26.0%. The result illustrates that the amount of Fe(2+) in the samples can be controlled using varied n(FeCl3)/n(FeCl2) in the feed. The diverse amount of Fe(2+) in this series of FeMOF materials exactly explains the distinction of reaction efficiency. The iron leaching tests, structures of the fresh and used catalysts, and the data of the recycling runs show that the Fe-containing MOFs are stable in this liquid-phase reaction.

The spherical shape, uniform size and small degree of agglomeration of the particles play crucial roles in promoting the practical applications of the phosphor powders. In this paper, the novel Eu3+ -doped cerium lutetium Ce2LuO5.5 composite nanopowders with a cubic fluorite structure were prepared via a typical solution combustion route, and their internal structure, surface morphology as well as luminescence properties were investigated. The Eu3+ could substitute in either Lu3+ or Ce4+ sites and the existence of oxygen vacancy was confirmed in the composite by X-ray diffraction and Raman spectra techniques. Without the addition of surfactant, most of the as-prepared particles were bound together, and the luminescence was very weak even after a sintering process. Assisted with appropriate polyvinyl alcohol (PVA) surfactant in the combustion reaction and a subsequent heat-treatment process, the bound-particles were evidently separated and seemed to be nearly spherical shape. The particle size could be controlled to 30–120 nm and the luminescence was enhanced by adjusting the subsequent sintering temperature. Excited with 466 nm blue light, the nanopowders exhibited characteristic 5D0 → 7FJ (J = 0–4) emission transition of Eu3+ and showed enhanced red luminescence as Eu3+ occupied Ce4+ site rather than Lu3+ site. The maximum emission was obtained as 40 mol% Eu substitutes Ce in the composite. Due to the coincidence of 466 nm excitation light with the emission of InGaN chips in white light-emitting diodes, the surface-morphology improved Eu-doped Ce2LuO5.5 phosphor nanopowders have a potential application in solid state lighting fields.