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To overcome the shortcomings of UV-Vis spectrometry and fluorescence spectrometry for COD detection, an online measurement named FfCODnet has been proposed and estimated in this paper. In this method, UV-Vis spectrum and fluorescence emission spectrum are collected online by a spectrophotometer, then De-noising Auto-Encoders (part of FfCODnet, abbreviated as DAE) are used to clean two types of raw spectrum respectively, finally the rest of FfCODnet is utilized to predict COD value of water sample. Through experiments and results comparison, the result shows that the proposed method has a good performance on both noise tolerance and measure accuracy.

Photocatalytic degradation of pollutants has been proved to be an effective strategy for wastewater treatment. Herein, TiO2 nanoparticles were synthesized on a Ti3C2 matrix by in situ growth, forming Z-scheme TiO2@Ti3C2/Cd0.5Zn0.5S (TO/CZS) multilevel structured nanocomposites via one-step hydrothermal route. The effects of hydrothermal temperature and Cd0.5Zn0.5S content on microstructure and properties of composites were assessed. TO/CZS nanocomposites were probed into phase composition, morphological and optical properties with x-ray diffractometer, infrared radiation, scanning electron microscope and UV–vis reflective spectra. Following the hydrothermal reaction at 160 °C for 12 h, TiO2 nanoparticles of 30 nm in diameter were generated in situ on Ti3C2 lamina and Cd0.5Zn0.5S particles were evenly distributed on the Ti3C2 matrix. The photocatalytic activity of TO/CZS composites were evaluated, which found that degradation rate constant (k = 0.028 min−1) of TO/CZS-40 on Rhodamine B was 5.19 times that of pure TiO2 and 4.48 times that of Cd0.5Zn0.5S. Through anchoring Ti3C2 as an electron transition mediator and combination with TiO2 and Cd0.5Zn0.5S, the new Z-scheme between TiO2 oxidized by Ti3C2 and Cd0.5Zn0.5S establishes a multilevel structure of separating electron-hole pairs. This work demonstrates a valid way to control electrons and hole transfer directions efficiently through designing multilevel semiconductor structural designs.

A design of ultrathin crystalline silicon solar cell with Si3N4 circular truncated cone holes (CTCs) arrays on the top is proposed. In this article, we perform an optical simulation of the structure. The finite-difference time-domain method is used to calculate the optical absorption of different periods, radius of top and bottom circles and depth of Si3N4 CTCs. The short-circuit current density generated by the optimized cells (30.17 mA/cm2) is 32.44% more than the value gained by control group (with flat Si3N4). Then adding a layer of back silver to allow us to better analyze optical absorption. Later, we simulate the optimization of the same configuration of different silicon thicknesses and find that our structure does enhance the light absorption. This work uses a combined path towards achieving higher photocurrent ultrathin crystalline silicon solar cells by constructing the texture of anti-reflection coating.

The evaluation of rock phase and reservoir property is the key problem to be solved in the exploration of deep sand conglomerate. The study of rock phase information is only in the qualitative stage according to the FMI logging data with the results are mainly image-lithologic models. It is urgent to extract gravel information based on image analysis. FMI image can be transformed into a vertical core gravel image after the operation of grayscale, blind area filling, image filtering, image segmentation and gravel extraction. The maximum gravel size is selected as the rock phase marker, and the statistical relationship of the conventional logging curves with resistivity, GR and density is established. It can provide a useful supplement for petrographic classification.

We investigate the Landau–Zener tunnelling of two-component Bose-Einstein condensates (BECs) in optical lattices. In the neighborhood of the Brillouin zone edge, the system can be reduced to two coupled nonlinear two-level models. From the models, we calculate the change of the tunnelling probability for each component with the linear sweeping rate. It is found that the probability for each component exhibits regular oscillating behavior for the larger sweeping rate, but for smaller rate the oscillation is irregular. Moreover, the asymmetry of the tunnelling between the two components can be induced by the unbalanced initial populations or the inequality of the two self-interactions when the cross-interaction between the components exists. The result can not be found in the single component BECs.

We report a structural design of ultrathin perovskite solar cells based on a conformal structure at the rear surface for potential applications in both single-junction and tandem cells. The light transmittances of the front and the rear surfaces are calculated in the wavelength range of 300–800 nm via the finite difference time domain numerical simulation method. Compared with the reference cell, significant photocurrent density enhancement of 27.5% and 29.7% are achieved when the ratios of height to width of the fluorine doped tin oxide nanoblock are 2 and 3, respectively. For the case with a hole transport material layer, the enhancements of photocurrent density enhancements are 19.2% and 29.0%, respectively. When back Au is removed, the photocurrent density also has notable enhancements of 23.3% and 45.9%, respectively. The achieved results are beneficial for the development of efficient ultrathin single-junction and tandem perovskite solar cells.

Outokumpu has developed a new duplex stainless steel with improved formability compared to other duplex grades. The so-called Forta FDX grades allows the utilization of duplex grades in more forming intensive products previously not possible and at the same time benefit from other duplex stainless steel properties for increased application performance. In this paper a Gasket Plate Heat Exchanger (GPHE) plate is formed with the new duplex grade Forta FDX 27 and compared to the baseline grade Supra 316L/4404. Detailed material characterization, strain measurements and Finite Element Analysis (FEA) were performed to further investigate the case. Small differences in measured strain distribution between Forta FDX 27 and Supra 316L/4404 were found after the stamping operation for both material grades and for the same design feature. Strain measurements showed reasonable agreement between measured experimental results and the numerical simulation for Forta FDX 27. Additionally, FEA predicts an improvement of the final strength of the product up to 30 % at the final configuration by using Forta FDX 27 instead of Supra 316L/4404.

The collective excitations of low-dimensional Bose–Einstein condensates with two- and three-body interactions in anharmonic potentials are investigated. Using the standard variational approach, the governing equations of motions for the low-energy excitations are obtained by solving time-dependent Gross–Pitaevskii–Ginzburg equation, and the excitation spectrums are calculated in small amplitude limit. The frequency shift and nonlinear mode coupling induced by the anharmonic distortion (adding cubic, quartic, or quintic term to a harmonic trap) are studied.

With the increasing share of the wind power in the power system, wind power fluctuations will cause obvious negative impacts on weak local grid. This paper firstly establish electromechanical transient simulation model for doubly fed induction wind turbine, then use Matlab/Simulink to achieve power flow calculation and transient simulation of power system including wind farms, the local synchronous generator, load, etc, finally analyze wind power on the impact of the local power grid under typical circumstances. The actual calculated results indicate that wind mutation causes little effect on the power grid, but when the three-phase short circuit fault happens, active power of wind power decreases sharply and the voltage of location of wind power into the grid also drop sharply, finally wind farm split from power system. This situation is not conducive to security and stability of the local power grid. It is necessary to develop security and stability measures in the future.

Based on the first-principles method, the structural stability and the contribution of point defects such as O, Sr or Ti vacancies on two-dimensional electron gas of n- and p-type LaAlO3/SrTiO3 interfaces are investigated. The results show that O vacancies at p-type interfaces have much lower formation energies, and Sr or Ti vacancies at n-type interfaces are more stable than the ones at p-type interfaces under O-rich conditions. The calculated densities of states indicate that O vacancies act as donors and give a significant compensation to hole carriers, resulting in insulating behavior at p-type interfaces. In contrast, Sr or Ti vacancies tend to trap electrons and behave as acceptors. Sr vacancies are the most stable defects at high oxygen partial pressures, and the Sr vacancies rather than Ti vacancies are responsible for the insulator-metal transition of n-type interface. The calculated results can be helpful to understand the tuned electronic properties of LaAlO3/SrTiO3 heterointerfaces.

Using the first principle method, we investigate the influence of Sr/Ti ratio on the atomic structure and dislocation behavior of Srn+1TinO3n+1(Ruddlesden—Popper phase) and SrnTin+1O3n+2 (Magneli phase). A linear lattice expansion versus the Sr/Ti ratio exhibits in the Ruddlesden—Popper and Magneli phases. The Ruddlesden—Popper phase has lower formation energy and superior structural stability than the Magneli phase. The two phases show different dislocation behaviors and it is found that a possibly preferred slip system 〈110〉 {110} emerges in the two phases, and the dislocations are more likely to dissociate into partial dislocations in Magneli phases.

A red-emitting CaZrO3:Eu3+ phosphor has been prepared by solid state reaction and its luminescent properties are studied. The crystal structure is investigated by the x-ray diffraction. Through energy transitions of 5D0 → 7FJ (J = 0, 1, 2, 3) in Eu3+ ions, the emission spectrum of the phosphor shows a series of narrow bands under near-ultraviolet light and the strongest peak locates at 613 nm. The emission intensity of Ca1−xZrO3:xEu3+ phosphor will reach the maximum as the molar concentration of Eu3+ is 5 mol%.

La0.5Sr0.5CoO3 (LSCO) films grown on SrTiO3 substrates, cooled at reduced oxygen pressures, ranging from 8×104 to 1×10−4 Pa, from the depostion temperature, are used as the bottom electrodes of PbZr0.4Ti0.6O3 (PZT) capacitors to study the impact of oxygen stoichiometry of the LSCO bottom electrodes on the structural and physical properties of LSCO/PZT/LSCO capacitors. It is found that the tetragonality, polarization and fatigue-resistance of PZT films decrease with the decrease of the cooling oxygen pressure. Almost 60% polarization degradation occurs for the PZT capacitor with the LSCO bottom electrode cooled in 1×10−4 Pa oxygen up to 1010 switching cycles, indicating that the oxygen vacancy of the bottom electrode can result in fatigue of the LSCO/PZT/LSCO capacitor.

The domain reversal characteristics of near-stoichiometric LiNbO3 ([Li]/[Li+Nb] = 0.496) single crystals, which are grown by the Czochralski method with K2O flux, are investigated. The switch field for 180° ferroelectric domain reversal in the near-stoichiometric LiNbO3 crystal is 8.0 ± 0.5 kV/mm, which is only one third of the switching field required for the congruent LiNbO3 crystals. We have successfully achieved 180° domain reversal in near-stoichiometric LiNbO3 samples of 1.0 mm thickness.

The electronic structures, magnetism, and half-metallicity of half-Heusler alloys XYZ (X = Mn, Ni; Y = Cr, Mn; Z = As, Sb) are investigated by means of the full-potential linearized augmented plane wave method within the generalized gradient approximation. We consider three types of atomic ordering (i.e., α, β, and γ phases for all of the alloys) and find that the α phase is energetically the most stable. From the calculated density of states and the total magnetic moments, we find that NiMnZ (Z = As, Sb) and NiCrAs are half-metallic ferromagnets, MnCrAs is a half-metallic antiferromagnet, and NiCrSb (MnCrSb) is almost a half-metallic ferromagnet (antiferromagnet).