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Cohesive elongated particles are ubiquitous in some industrial particle and powder processing operations; however, only a few studies investigated the kinematics of such particles using a discrete element method (DEM). Therefore, in this study, a DEM-based model was used to investigate the kinematics of cohesive elongated particles agitated in a vertical axis mixer. A contact-area-proportional model accounting for sphero-cylindrical particle geometry was employed for modeling particle–particle and particle–boundary cohesion. Generally, the flow patterns of the elongated particles in the vertical axis mixer remain stable as the particle cohesion level increases from no cohesion to low cohesion. However, flow pattern differences appear when the particle cohesion level increases to high cohesion, including the formation of large agglomerates, particle adhesion to the drum base and sidewall, and a significant heap height increase owing to the large angle of repose which high cohesion particles could maintain. Overall increasing the particle cohesion level increases the mass flow rate of particles over the blade, emphasizing the importance of particle cohesion of the bed. At the condition of high cohesion, the variation of the flow rate over the blade is significantly higher than that for no cohesion or low cohesion.

Lithium-ion batteries are being increasingly used as the main energy storage devices in modern mobile applications, including modern spacecrafts, satellites, and electric vehicles, in which consistent and severe vibrations exist. As the lithium-ion battery market share grows, so must our understanding of the effect of mechanical vibrations and shocks on the electrical performance and mechanical properties of such batteries. Only a few recent studies investigated the effect of vibrations on the degradation and fatigue of battery cell materials as well as the effect of vibrations on the battery pack structure. This review focused on the recent progress in determining the effect of dynamic loads and vibrations on lithium-ion batteries to advance the understanding of lithium-ion battery systems. Theoretical, computational, and experimental studies conducted in both academia and industry in the past few years are reviewed herein. Although the effect of dynamic loads and random vibrations on the mechanical behavior of battery pack structures has been investigated and the correlation between vibration and the battery cell electrical performance has been determined to support the development of more robust electrical systems, it is still necessary to clarify the mechanical degradation mechanisms that affect the electrical performance and safety of battery cells.

Many strategies have been employed to maintain an “optimal carrier concentration” to achieve a high thermoelectric power factor in n-type PbTe. Here, we show that a high power factor can also be ac...

The temperature distribution in a 3-D high-power light emitting diode lamp is affect by multiple factors, the orthogonal experiment method is adopted to elucidate three main factors, an experiment is designed to verify the main finding, which is useful for an optimal design of the light emitting diode lamp.

In a 3-D integrated circuit the heat source distribution has a huge effect on the temperature distribution, so an optimal heat source distribution is needed. This paper gives a numerical approach to its thermal optimization, the result can be used for 3-D integrated circuit optimal design.

Properties of solids are strongly influenced by their crystal structures. Learning from the structure–property relationships of existing high-performance thermoelectrics (TEs), here we identify a f...

Using first-principles density functional calculations, we study the phase stability and cation ordering behavior in ABX2, PbX-ABX2, and SnTe-ABTe2 (A = Na, Ag; B = Sb; X = S, Se, Te) thermoelectri...

Bioprocess for successive bio-production of glycolic acid (GA) from ethylene glycol (EG) using Gluconobacter oxydans is hindered by strong end-product inhibitory effect. Based on the model of compressed oxygen supplied-sealed stirred tank reactor (COS-SSTR), we developed a new system by attaching an ultrafiltration instrument and electrodialysis cell to in-situ separate GA, including conductivity meter to control automatic EG feeding. The combined bioprocess was therefore set up as compressed oxygen supplied cell catalysis-ultrafiltration-electrodialysis (COS-CUE). In comparison with the conventional resin and electrodialysis separation process, this device simplified the whole bioprocess. We realized the potential of combined bioprocess for producing GA without EG through continuous/semi-continuous ‘one-step’ process. Finally, 288.4 g GA was obtained at the yield of 96.5% and average productivity of 4.0 g/L/h in 72 h, with an increment of 148.8% and 20.9% in production compared with batch and cell-recycling fermentation.

The through silicon via technology is a promising and preferred way to realize the reliable interconnection for 3-D integrated circuit integration. However, its size and the property of the filled-materials are two factors affecting the thermal behavior of the integrated circuits. In this paper, we design 3-D integrated circuits with different through silicon via models and analyze the effect of different material-filled through silicon vias, aspect ratio and thermal conductivity of the dielectric on the steady-state temperature profiles. The results presented in this paper are expected to aid in the development of thermal design guidelines for through silicon vias in 3-D integrated circuits.

Gas-fluidized beds of flexible fibres, which have been rarely studied before, are investigated in this work using the coupled approach of the discrete element method and computational fluid dynamics. In the present numerical method, gas–fibre interaction is modelled by calculating the interaction force for each constituent element in the fibre, and the composition of the interaction forces on the constituent elements generates a resultant hydrodynamic force and a resultant hydrodynamic torque on the fibre. Pressure drops and fibre orientation results from the present simulations with various fibre aspect ratios are in good agreement with previous experimental and simulation results. Some novel results are obtained for the effects of fibre flexibility. Larger hydrodynamic forces on fibres (before the bed is fluidized) and smaller minimum fluidization velocities (MFVs) are observed for more flexible fibre beds due to the smaller porosities, while smaller hydrodynamic forces are obtained for the more flexible fibres when the beds are fluidized with significant fibre motion. By scaling the superficial gas velocity using the MFVs, the data of pressure drop can collapse onto the Ergun correlation for stiff fibres of various aspect ratios; however, the pressure drop curves deviate from the Ergun correlation for very flexible fibres, due to the significant fibre bed expansion before the MFV is reached. The fibre aspect ratio and flexibility both have an impact on the solids mixing rate, and it is found that the solids mixing rates are essentially determined by the ratio of the superficial gas velocity to MFV.

Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures. Although great progress has been made in the metasurface designs and function demonstrations, most metalenses still only work as a substitution of conventional lenses in optical settings, whose integration advantage is rarely manifested. We propose a highly integrated imaging device with silicon metalenses directly mounted on a complementary metal oxide semiconductor image sensor, whose working distance is in hundreds of micrometers. The imaging performances including resolution, signal-to-noise ratio, and field of view (FOV) are investigated. Moreover, we develop a metalens array with polarization-multiplexed dual-phase design for a wide-field microscopic imaging. This approach remarkably expands the FOV without reducing the resolution, which promises a non-limited space-bandwidth product imaging for wide-field microscopy. As a result, we demonstrate a centimeter-scale prototype for microscopic imaging, showing uniqueness of meta-design for compact integration.

Thermal transport phenomena are ubiquitous and play a critical role in the performance of various microelectronic and energy-conversion devices. Binary rocksalt and zinc blende compounds, despite their rather simple crystal structures, exhibit an extraordinary range of lattice thermal conductivity (κ_{L}) spanning over 3 orders of magnitude. A comprehensive understanding of the underlying heat transfer mechanism through the development of microscopic theories is therefore of fundamental importance, yet it remains elusive because of the challenges arising from explicitly treating higher-order anharmonicity. Recent theoretical and experimental advances have revealed the essential role of quartic anharmonicity in suppressing heat transfer in zinc blende boron arsenide (BAs) with ultrahigh κ_{L}. However, critical questions concerning the general effects of higher-order anharmonicity in the broad classes and chemistries of binary solids are still unanswered. Using our recently developed high-throughput phonon framework based on first-principles density functional theory calculations, we systematically investigate the lattice dynamics and thermal transport properties of 37 binary compounds with rocksalt and zinc blende structures at room temperature, with a particular focus on unraveling the impacts of quartic anharmonicity on κ_{L}. Our advanced theoretical model for computing κ_{L} embraces current state-of-the-art methods, featuring a complete treatment of quartic anharmonicity for both phonon frequencies and lifetimes at finite temperatures, as well as contributions from off-diagonal terms in the heat-flux operator. We find the impacts of quartic anharmonicity on κ_{L} to be strikingly different in rocksalt and zinc blende compounds, owing to the countervailing effects on finite-temperature-induced shifts in phonon frequencies and scattering rates. By correlating κ_{L} with the phonon scattering phase space, we outline a qualitative but efficient route to assess the importance of four-phonon scattering from harmonic phonon calculations. Among notable examples, in zinc blende HgTe, we identify an unprecedented sixfold reduction in κ_{L} due to four-phonon scattering, which dominates over the three-phonon scattering in the acoustic region at room temperature. We also demonstrate a possible breakdown of the phonon gas model in rocksalt AgCl, wherein the phonon states are significantly broadened due to strong intrinsic anharmonicity, inducing off-diagonal contributions to κ_{L} comparable to the diagonal ones. The deep physical insights gained in this work can be used to guide the rational design of thermal management materials.

The dynamics of spiral bevel gears have gained increasing importance due to concerns relating to noise and durability. This is because the mesh force acting on the gear teeth is amplified under dynamic conditions, potentially reducing the fatigue life of the gears. Furthermore, a sizable dynamic force can be transmitted to the housing, inducing structure-born gear whine. The elasticity of the bearings can influence the dynamics of spiral bevel gears. In this article, the finite element formulation of a spiral bevel geared rotor dynamic system is applied to investigate the influence of bearing elasticity on the dynamics of spiral bevel gears. The designs and configurations of rear axles are modeled and analyzed for real-world applications, to gain an enhanced practical understanding of the effect of bearing stiffness on spiral bevel gear dynamics.

The introduction of an alkaline earth metal telluride as a second phase in PbTe can lead to very high thermoelectric figure of merit, ZT, as a result of hierarchical structuring, e.g., in the PbTe–SrTe system. However, there are two roadblocks to this strategy: poor solubility and occurrence of incoherent nanoprecipitates in the PbTe matrix, e.g., the PbTe–BaTe system. Here we demonstrate a dual alloying approach by simultaneously alloying CaTe and BaTe in the p-type PbTe matrix to achieve ZTmax ranging up to ∼2.2 at high temperatures. Synergistic enhancement of the Seebeck coefficient via favorable band convergence gives rise to higher power factors up to 34 μW cm–1 K–2 and significant suppression of lattice thermal conductivity, κL, down to ∼0.6 W m–1 K–1 results from large multicenter phonon scattering. Additionally, co-inclusion of Ca and Ba causes unanticipated lattice hardening in otherwise brittle PbTe, essential for practical device applications.

The interference between overlapping gas absorption lines often occurs in the measurement of multi-component gas mixture with using tunable diode laser absorption spectroscopy (TDLAS). This is also the main problem of the technology in some applications. For instance, in the early application of multi-component gas mixture measurement in coal mines, we found that the absorption lines of carbon monoxide (CO) and methane (CH4) seriously overlapped. The absorption signal of trace CO gas was annihilated and could not be effectively demodulated, especially in the presence of high concentration of CH4. This problem could not be solved just by accurately selecting the spectral lines due to the band absorption of CH4. Therefore, in this paper, we introduce the support vector regression (SVR) model to deal with the interference between CO and CH4 absorption lines. The spectral signals of 14 groups of mixed gases with different concentrations of CO and CH4 are used as the training sets, and the five-fold cross-validation is adopted to prevent the model from overfitting. After 15 iterations in 30 seconds, the optimal regression model of CO and CH4 can be obtained respectively. Furthermore, it is worth noting that based on the experimental data, the linear kernel function is selected to construct the two gas SVR models, and the parameters of the SVR models are optimized by the sequential minimal optimization(SMO) algorithm. With the assistance of the SVR models, the absorption spectra of the two gases can be demodulated effectively, and finally the accurate measurement results are obtained. The measurement results show that the absolute error of trace CO and CH4 concentration(volume fraction of gas) are less than 2 × 10–6 and 0.2 × 10–2 respectively. Meanwhile, the correlation coefficient between the measured values and the actual values of CO and CH4 are 0.998 and 0.9995, respectively. In addition, the dynamic stability for each of the two regression models is fully verified by the experiment of the inflation process. Consequently, this method can eliminate the interference between the overlapping spectra, and can fully meet the requirements for accurately measuring the gas mixture. We hope that the SVR model can provide an effective solution for the real-time monitoring of multi-component gas mixture, and thus greatly improving the adaptability of TDLAS technology in the future.

Hybrid materials of CoFe2O4 nanoparticles anchored on graphene prepared by a facile hydrothermal process was developed to be anode material for sodium-ion battery. The hybrid nano-structure of CoFe2O4/graphene not only could be useful to buffer electrode volume accompanying with Na+ insertion–extraction, but also could be beneficial to improve electrode electric conductivity and further keep graphene sheet separated to improve ion diffusion rate. Electrochemical measurements showed that the hybrid material anode displayed an excellent performance with a large reversible capacity of 330 mAh g−1 after 75 cycle times and a satisfactory rate capability of 170 mAh g−1 at 1 A g−1.

We present first-principles calculations of the solid-state phase diagram of PbTe-SrTe that include both configurational and vibrational contributions to the free energy. These configurational and vibrational free energies were calculated using the cluster expansion (CE) approach and quasiharmonic phonon calculations, respectively. The coupled configurational and vibrational degrees of freedom were taken into account by including temperature-dependent CE interactions with the $T=0\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ values and temperature dependence of the interactions determined from total energies and phonon free energies, both calculated using density functional theory. This Hamiltonian was then employed in Monte Carlo simulations to obtain a quantitative prediction of the PbTe-SrTe phase diagram. The phase diagram consists of a miscibility gap with a maximum temperature of \ensuremath{\sim}500 K, with the inclusion of the vibrational entropy resulting in a more than fourfold increase in the calculated solubility limits of SrTe in PbTe. Our results suggest that the equilibrium solubility of this system is likely much larger than previously thought and deserves further experimental investigation.

Single crystalline SnSe is one of the most intriguing new thermoelectric materials but the thermoelectric performance of polycrystalline SnSe seems to lag significantly compared to that of a single crystal. Here an effective strategy for enhancing the thermoelectric performance of p‐type polycrystalline SnSe by Ag/Na dual‐doping and Ag8SnSe6 (STSe) nanoprecipitates is reported. The Ag/Na dual‐doping leads to a two orders of magnitude increase in carrier concentration and a convergence of valence bands (VBM1 and VBM5), which in turn results in sharp enhancement of electrical conductivities and high Seebeck coefficients in the Ag/Na dual‐doped samples. Additionally, the SnSe matrix becomes nanostructured with dispersed nanoprecipitates of the compound Ag8SnSe6, which further strengthens the scattering of phonons. Specifically, ≈20% reduction in the already ultralow lattice thermal conductivity is realized for the Sn0.99Na0.01Se–STSe sample at 773 K compared to the thermal conductivity of pure SnSe. Consequently, a peak thermoelectric figure of merit ZT of 1.33 at 773 K with a high average ZT (ZTave) value of 0.91 (423–823 K) is achieved for the Sn0.99Na0.01Se–STSe sample. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore)

Sb-doped and GeTe-alloyed n-type thermoelectric materials that show an excellent figure of merit ZT in the intermediate temperature range (400–800 K) are reported. The synergistic effect of favorable changes to the band structure resulting in high Seebeck coefficient and enhanced phonon scattering by point defects and nanoscale precipitates resulting in reduction of thermal conductivity are demonstrated. The samples can be tuned as single-phase solid solution (SS) or two-phase system with nanoscale precipitates (Nano) based on the annealing processes. The GeTe alloying results in band structure modification by widening the bandgap and increasing the density-of-states effective mass of PbTe, resulting in significantly enhanced Seebeck coefficients. The nanoscale precipitates can improve the power factor in the low temperature range and further reduce the lattice thermal conductivity (κlat). Specifically, the Seebeck coefficient of Pb0.988Sb0.012Te–13%GeTe–Nano approaches −280 µV K−1 at 673 K with a low κlat of 0.56 W m−1 K−1 at 573 K. Consequently, a peak ZT value of 1.38 is achieved at 623 K. Moreover, a high average ZTavg value of ≈1.04 is obtained in the temperature range from 300 to 773 K for n-type Pb0.988Sb0.012Te–13%GeTe–Nano. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore)

A discrete element method (DEM) model is used to predict the internal load and moment distribution within rod-like particles in a low-speed, vertical axis mixer. The internal loads and moments are combined with small deformation beam bending theory to determine the internal stress distributions. Parametric studies using the model examined the influence of particle aspect ratio, blade rotational speed, and material properties. The spatial distributions of loads and moments, averaged over all particles and time steps, are symmetric about the particle center-plane with a maximum at the particle center-plane. In addition, the largest average maximum absolute principal stress is observed to occur along the particle circumference at the center-plane of the particle. These results indicate that particle failure is not only most likely to occur at the center-plane of the particle, but the failure will begin at the particle’s circumference. The largest average loads, moments, and maximum absolute principal stress increase with particle aspect ratio. The frequency distributions of maximum absolute principal stress at the high stress range are fit well with a Weibull distribution. Increasing blade speed, bed height and particle–particle friction coefficient generally lead to an increase in internal loads, moments, and stresses. The largest maximum absolute principal stresses occur at the base of the mixer and in front of the blades near the mixer circumference where the bed depth is the greatest.

Broadband coherent Raman generation emerges as a successful method to produce multicolored femtosecond pulses and time-shaped laser fields. In our study, coherent Raman sidebands are generated in a Raman-active crystal, driven by two-color femtosecond laser pulses. An interferogram of the sidebands based on coherent Raman scattering is produced in a novel reflection scheme. The relative spectral phases of the sidebands are obtained from the interferogram using a numerical simulation. This enables us to retrieve the ultrafast waveform using coherent Raman sidebands.

Herein, an efficient Ce-doped MoO 3 catalyst is prepared by an impregnation method. Under visible light irradiation (≥ 420 nm) or light-off, Ce(5)-doped MoO 3 shows a degradation activity of methylene blue (MB) dye 10 times higher than MoO 3 due to the doped Ce. It is proposed that the light-off degradation is predominated by a Mo/Ce redox cycle, instead of a photocatalytic reaction; while the light-on degradation is via a synergetic effect of both photocatalytic oxidation and Mo/Ce redox cycle. This study offers a new concept for environmental cleaning from cost-saving and energy-saving viewpoints.

Peaks, dips, and intermediate line shapes have been observed in surface-enhanced coherent Raman spectroscopy. Here, we report an experimental observation of a peculiar line shape revealing both a peak and a dip as two vibrational transitions of pyridazine in the presence of aggregated gold nanoparticles. We propose a simple model based on plasmonic phase effects and quantum chemistry calculations, and compare the simulated coherent (SECARS) and incoherent (SERS) Raman signals from several complexes. Complex SECARS line shapes provide additional information compared to SERS and can be used as a tool in nanoscale sensing and spectroscopy.

The novel three-dimensional (3D) silver phosphate tetrapods (TA) are synthesized and employed as a super capacitor electrode material. The electrochemical properties are investigated by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). It is interesting that compared with irregular silver phosphate particles (IA), TA shows a higher capacitance (250 vs. 160 F g−1), and a higher coulombic efficiency (80% vs. 74%), which is mainly ascribed to the 3D microstructure and its high conductivity. To the best of our knowledge, this is the first report on silver phosphate as a super capacitor material.

Uniform and well-defined CuO cauliflowers have been prepared via a simple hydrothermal route, which form through the “oriented attachment (OA)–preferential growth–Ostwald ripening (OR)” processes. Furthermore, the CuO cauliflowers show a much higher activity than the irregular CuO for the degradation of rhodamine B (RhB). Its apparent rate constant (0.0156 min − 1 ) is 5.24 times higher than that (0.0025 min − 1 ) of the latter. The higher activity is mainly attributed to its higher crystallinity (84.02% vs. 62.86%), which can reduce the recombination rate of photogenerated electrons and holes.

CuO/TiO2 composites were prepared by the impregnation method, in which TiO2 nanosheets and nanorods are used as the precursors, respectively. We investigated the effect of the TiO2 surface structure on the activity and recyclability of the photocatalysts. The hydrogen production activities were tested in a 3 mol L−1 methanol aqueous solution under UV-light irradiation. After deposition of Pt, both Pt@CuO/TiO2 samples displayed higher hydrogen production activities than the Pt/TiO2 samples. The results reveal that the TiO2 sheet-based samples display higher hydrogen production activities and stability than the TiO2 rod-based ones. It is proposed that a more stable p–n heterojunction form at the interface between CuO and TiO2 nanosheets owing to the strong interaction of CuO with the {0 0 1} facets of the TiO2 sheets, which significantly refrains the recombination rate of electrons and holes.

Lens-free holographic microscopy could achieve both improved resolution and field of view (FOV), which has huge potential applications in biomedicine, fluid mechanics and soft matter physics. Unfortunately, due to the limited sensor pixel size, target objects could not be located to a satisfactory level. Recent studies have shown that electromagnetic scattering can be fitted to digital holograms to obtain the 3D positions of isolated colloidal spheres with nanometer precision and millisecond temporal resolution. Here, we describe a lens-free holographic imaging technique that fits multi-sphere superposition scattering to digital holograms to obtain in situ particle position and model parameters: size and refractive index of colloidal spheres. We show that the proposed method can be utilized to analyze the location and character of colloidal particles under large FOV with high density.

Three 3D Ln(III)–Zn(II) 3d-4f heterometallic coordination polymers (HCPs) constructed from the coligands 3-amino-1H-1,2,4-triazole and oxalate, {[Ln2Zn19(atz)18(ox)9(Cl)8]·17H2O}n(Ln = Eu 1, Gd 2, Tb 3, Hatz = 3-amino-1H-1,2,4-triazole, ox = oxalic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and X-ray diffraction. X-ray diffraction analysis reveals that these complexes are isostructural and feature 3D pillar-layered coordination frameworks constructed by the linkages of 2D layers and 1D zigzag chains, possessing a 5-nodal net topology with Schlafli symbol of {32;52;62}3{33;44;57;65;72}6{33;45;55;6;7}6{36;415;56;6}2{53}4. In addition, the magnetic property of 2 and the luminescence properties of 1 and 3 were also investigated.

A series of Ln(III)-Ag(I) 4d–4f heterometallic coordination polymers [LnAg(oba)2(H2O)]n (Ln = Dy 1, Ho 2, Er 3) have been synthesized under hydrothermal reactions of 4,4′-oxybis(benzoicacid) (H2oba) with Ln(NO3)3 · 6H2O and AgNO3 at 180 °C. All complexes are isostructural with 3D networks expanded from 1D zigzag chains and 2D layers. In addition, the luminescent property of compound 1 was investigated in the solid-state at room temperature.

Novel porous Co3O4 cubes are prepared by a simple hydrothermal method and a Co3O4-based chemiluminescence (CL) sensor is fabricated. The samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (ED), N2 adsorption, CO- and O2-temperature programmed desorption (CO- and O2-TPD), etc. The CL properties of the sensors are measured, and the catalytic oxidation properties of the samples are also investigated. The results show that the Co3O4 cubes are assembled from subunits of nanoparticles, which results in porous structure. Compared with the bulk Co3O4-based sensor, the porous Co3O4 one has a higher CL intensity and a higher catalytic oxidation activity, which has been ascribed to the porous structure and the high surface area. Most importantly, the Co3O4 assemblies-based sensor can be used as an effective method for judging catalyst activity or selecting excellent catalysts

In this work, the LiFePO4 nanorods are synthesized in an ionic liquid (IL) in the presence of a surfactant. The samples are characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, electron diffraction and nitrogen adsorption. The as-obtained LiFePO4 nanorods in the IL have the diameter of about 200 nm and the length of 1–2 μm; but the aggregated LiFePO4 microparticles are obtained in the aqueous solution. The results show that a higher temperature and a longer duration are needed in the IL than in the aqueous solution for the formation of LiFePO4; that both IL and the surfactant play the key roles in the formation of LiFePO4 nanorods. Furthermore, their charge and discharge properties are investigated. The LiFePO4 nanorods show a higher discharge capacity (150 at 1C rate) and a higher rate capability than the aggregated particles (133 mAh g−1). The adopted IL approach may provide a “green” route to achieve excellent battery materials.

As a high-quantum-efficiency photocatalyst, the serious photo-corrosion of silver phosphate (Ag3PO4), limits the practical applications in water purification and challenges us. Herein, Ag3PO4 is found to have a high stability under natural indoor weak light irradiation, suggesting that we can employ it by adopting a new application strategy. In our studies, rhodamine B (RhB, cationic dye), methyl orange (MO, anionic dye) and RhB-MO mixture aqueous solutions are used as the probing reaction for the degradation of organic wastewater. It is found that RhB, MO and RhB-MO can be completely degraded after 28 h under natural indoor weak light irradiation, indicating that multi-component organic contaminants can be efficiently degraded by Ag3PO4 under natural indoor weak light irradiation. The density of natural indoor weak light is measured to be 72cd, which is merely one-thousandth of 300 W xenon lamp (68.2 × 10(3)cd). Most importantly, Ag3PO4 shows a high stability under natural indoor weak light irradiation, demonstrated by the formation of fairly rare Ag. Furthermore, we also investigate the influence of inorganic ions on organic dyes degradation. It shows that the Cl(-) and Cr(6+) ions with high concentrations in wastewater have significantly decreased the degradation rate. From the viewpoint of energy saving and stability, this study shows us that we can utilize the Ag-containing photocatalysts under natural indoor weak light, which could be extended to indoor air cleaning process.

The xFe2O3/yBiOCl composites (xFe/yBi, x/y = 0/100, 5/100, 10/100, 20/100, 30/100 and 40/100 molar ratios) are prepared for the first time through an in situ hydrolysis method under hydrothermal conditions. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and UV-visible diffuse reflectance spectroscopy (UV-DRS). The photodegradation performances of the xFe/yBi samples are investigated using a simulated industrial wastewater mixture containing both rhodamine B (RhB) and methyl orange (MO). The uniform Fe2O3 nanocubes are found to be well distributed on the BiOCl nanosheets. Moreover, the xFe/yBi photocatalysts exhibit unexpectedly higher efficiencies than bare BiOCl or Fe2O3 under ultraviolet light irradiation (λ ≤ 420 nm). Specifically, the degradation rates of the xFe/yBi samples at x/y = 5/100 and 10/100 are four times higher than that of bare BiOCl for MO–RhB mixed dye solutions. Their high photocatalytic activities are mainly attributed to the formation of stable p/n heterojunctions between Fe2O3 and BiOCl, which greatly improve the separation of photogenerated carriers. Importantly, the highly efficient and inexpensive xFe/yBi p/n heterojunctions are expected to be useful in practical industrial wastewater applications involving complicated toxic components.

A series of nanostructured Ni–Zn ferrites Ni 1− x Zn x Fe 2 O 4 ( x =0, 0.5 and 1) with a grain size from 24 to 65 nm have been prepared with a sol–gel method. The effect of composition and sintering temperature on morphology, magnetic properties, Curie temperature, specific heating rate at 295 kHz and hysteresis loss have been studied. The highest coercivity of 50 and 40 Oe, were obtained for NiFe 2 O 4 and Ni 0.5 Zn 0.5 Fe 2 O 4 samples with the grain size of 35 and 29 nm, respectively. The coercivity of Ni and Ni–Zn mixed ferrites decreased with temperature. The Bloch exponent was 1.5 for all samples. As the grain size increased, the Curie temperature of NiFe 2 O 4 increased from 849 to 859 K. The highest saturation magnetization of 70 emu/g at 298 K and the highest specific heating rate of 1.6 K/s under radiofrequency heating at 295 kHz were observed over NiFe 2 O 4 calcined at 1073 K. Both the magnitude of the hysteresis loss and the temperature dependence of the loss are influenced by the sintering temperature and composition.

We demonstrate energy exchange between two filament-forming femtosecond laser beams in liquid methanol. Our results are consistent with those of previous works documenting coupling between filaments in air; in addition, we identify an unreported phenomenon in which the direction of energy exchange oscillates at increments in the relative pulse delay equal to an optical period (2.6 fs). Energy transfer from one filament to another may be used in remote sensing and spectroscopic applications utilizing femtosecond laser filaments in water and air.

We use diamond to produce femtosecond broadband coherent Raman generation akin to molecular modulation. We achieve shape control of few-cycle pulses by combining coarse manual phase adjustment with fine tuning via a programmable pulse shaper.