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In this paper, a novel maximum likelihood sequence estimation (MLSE) optimum receiver design is proposed to reduce the complexity of the conventional optimum receiver. We first propose a multipath channel classification method according to the zero distribution of the channel impulse response; that is, the multipath channel is divided into a minimum phase channel and a non-minimum phase channel. Then, an MLSE optimum receiver design with channel identification based on zero distribution is also proposed. In this design, the distribution of zero can be obtained directly by calculating the Z transform of the channel. Thus, the complexity is reduced. The number of the multiplication reduced is N (2 N + 1) . In addition, 2 N + 1 memory units storing the autocorrelation sequence are reduced. The simulation results indicate that this channel classification method effectively represents the characteristics of the channel. Moreover, the MLSE optimum receiver proposed performs similarly and is less complex than the conventional one. The performance is greatly improved compared with the minimum mean square error (MMSE) equalizer. [ABSTRACT FROM AUTHOR]

Photo‐rechargeable zinc‐ion batteries (PRZIBs) have attracted much attention in the field of energy storage due to their high safety and dexterity compared with currently integrated lithium‐ion batteries and solar cells. However, challenges remain toward their practical applications, originating from the unsatisfactory structural design of photocathodes, which results in low photoelectric conversion efficiency (PCE). Herein, a flexible MoS2/SnO2‐based photocathode is developed via constructing a sunflower‐shaped light‐trapping nanostructure with 3D hierarchical and self‐supporting properties, enabled by the hierarchical embellishment of MoS2 nanosheets and SnO2 quantum dots on carbon cloth (MoS2/SnO2 QDs@CC). This structural design provides a favorable pathway for the effective separation of photogenerated electron‐hole pairs and the efficient storage of Zn2+ on photocathodes. Consequently, the PRZIB assembled with MoS2/SnO2 QDs@CC delivers a desirable capacity of 366 mAh g−1 under a light intensity of 100 mW cm−2, and achieves an ultra‐high PCE of 2.7% at a current density of 0.125 mA cm−2. In practice, an integrated battery system consisting of four series‐connected quasi‐solid‐state PRZIBs is successfully applied as a wearable wristband of smartwatches, which opens a new door for the application of PRZIBs in next‐generation flexible energy storage devices. [ABSTRACT FROM AUTHOR]

As a visible-light response semiconductor materials, bismuth vanadate (BiVO4) is extensively applied in photodegradation organic dye field. In this study, we synthesized C3N5 nanosheets and coupled with decahedral BiVO4 to construct a Z-scheme C3N5/BiVO4 heterostructure with close interface contact. By introducing C3N5 into BiVO4, the built Z-scheme transfer pathway provides silky channel for charge carrier migration between different moieties and enables photoexcited electrons and holes accumulated on the surface of BiVO4 and C3N5. The accelerated separation of charge carriers ensures C3N5/BiVO4 heterostructures with a powerful oxidation capacity compared with pure BiVO4. Due to the synergistic effect in Z-scheme heterostructure, the C3N5/BiVO4 demonstrated an improved photodegradation ability of rhodamine B (RhB) and methylene blue (MB) that of bare BiVO4. [ABSTRACT FROM AUTHOR]

The effective utilization of the local surface plasmon resonance (LSPR) effect of metal nanoparticles to improve optical absorption capacity and inject hot electrons into photocatalysts opens up new directions and ideas to solve the problem of solar energy utilization efficiency of photocatalysts. In this study, we created an in situ technique for preparing plasmon Ag nanoparticles (NPs) decorated with a covalent organic framework (COF), named Ag/TpPa-1-COF. The LSPR effect of Ag NPs results in an outstanding rate of H2 production that is 801.4 μmol g−1 h−1 for the 3% Ag/TpPa-1 photocatalyst, which is almost 4 times as effective as that of the unmodified TpPa-1-COF. Moreover, finite-difference time-domain (FDTD) simulation results reveal that the strongest electric field intensity is presented when the catalyst is excited at λ = 465 nm. Furthermore, plasmonic "hot spots" induced by the interfacial electric field enhancement factor distribution of Ag/TpPa-1 were simulated in detail by adjusting the number, particle size, and gap distance of Ag NPs. Additionally, density functional theory (DFT) calculations show that electron transfer from Ag NPs to TpPa-1 occurs at the Ag/TpPa-1 interface, and N sites in Ag/TpPa-1 exhibit low Gibbs free energy (ΔGH*) for enhanced photocatalytic H2 evolution. Overall, this research provides new insights into the plasmonic "hot spot" region that performs effectively for hydrogen evolution. [ABSTRACT FROM AUTHOR]

A dispersion containing black TiO2 photocatalyst was prepared and sprayed onto the concrete's surface to achieve a black TiO2-based photocatalytic concrete paving eco-block, and its photocatalytic NO removal ratio is approximately 1.7 times as high as that of a white TiO2-based eco-block, resulting from the enhanced optical absorption intensity, abundant oxygen vacancies, and highly produced superoxide anion radicals (˙O2−) of black TiO2. Moreover, the black TiO2-based concrete paving eco-block exhibits significantly enhanced compressive strength and abrasion resistance when using water-glass as a binder, which could satisfy the demand for practical application. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was performed to dynamically track the reactive products and intermediates across the surface of the B-TiO2 photocatalyst in a time sequence to investigate the reaction mechanism. It has been demonstrated that almost no harmful by-products were produced when NO was removed via photocatalysis, and the applicability of the as-prepared eco-blocks was evaluated considering the effects of various reaction conditions. Additionally, a computational fluid dynamics (CFD) model for solar-driven photocatalytic abatement of atmospheric NO in a realistic urban street coating with black TiO2-based photocatalytic concrete paving eco-blocks was constructed and simulated to assess the real-world applicability of the developed approach. Overall, this research may offer fresh perspectives on how to create ecologically acceptable photocatalytic products for the removal of air pollutants using solar light. [ABSTRACT FROM AUTHOR]

To enhance the reliability of UAV-to-Ground data transmission in SC-FDE, this study proposes a combined MMSE equalization and LDPC-RS concatenated code approach, utilizing source redundancy to mitigate errors in low-elevation G2A communication. The proposed coding scheme combines a binary LDPC code as the outer code and an improved RS code as the inner code, resulting in improved resistance to burst and random errors. To address the coding aspect, this paper designs a coding table using RS coding as the underlying logic, enabling efficient coding. For decoding, a decoding scheme based on the minimum Euclidean distance criterion is devised, enabling high-performance decoding. Simulation results demonstrate that the proposed LDPC-RS concatenated coding scheme significantly enhances the performance of the communication system, thereby offering considerable potential for application in UAV video transmission systems. [ABSTRACT FROM AUTHOR]

In this study, Pt-M/WO3 (M = Cu, Co, and Ni) thin films are effectively synthesized by preparing homogeneous precursor sols, spin-coating, toluene-etching, and calcination. Furthermore, the microstructural, chemical, and electrochemical properties of the WO3, Pt-Cu/WO3, Pt-Co/WO3, and Pt-Ni/WO3 thin films are also systematically compared. The results demonstrate that when compared to the WO3 thin film, the photocatalytic capability for methylene blue (MB) solution degradation is greatly increased in the Pt-M/WO3 thin films. Transfer routes for photogenerated charges and an improved photocatalytic process are suggested based on the experimental results. Due to the large difference in the work function (Φ) between the bimetallic alloy Pt-M and WO3, a bending of the energy bands at the Pt-M/WO3 interface is presented. Furthermore, the introduction of transition metals such as Cu, Co, or Ni modifies the electronic structure of Pt-M/WO3 thin films, facilitating the separation and migration of electrons and holes. Specifically, the photogenerated electrons migrate from the CB of WO3 to Pt-Co or Pt-Ni nanoparticles in the samples of Pt-Co/WO3 or Pt-Ni/WO3 thin films, while the hot electrons from the localized surface plasmon resonance (LSPR) effect of Cu could transfer to the conduction band (CB) of WO3 and other electrons generated from the photoexcitation of the WO3 semiconductor itself in the sample of the Pt-Cu/WO3 thin film. In summary, this work proposes a unique strategy for creating electron regulation in Pt-M decorated WO3 thin films for photocatalytic application. [ABSTRACT FROM AUTHOR]

It has been rarely reported the morphological control of derivatives of metal‐organic frameworks (MOFs) in hydrothermal conditions for photocatalytic applications. We report here a family of highly efficient composite photocatalysts composed of terephthalic acid/terephthalate (TPA) ligand and TiO2 with various morphologies (e. g. nanoparticles, nanosheets, and nanorods). The composites are synthesized by a simple one‐step hydrothermal method in various solvents (i. e. H2O, HF, H2SO4, HCl, and HNO3) using Ti‐based MOF (MIL‐125(Ti)) as precursor. The formation mechanism of composite materials with different morphological features is discussed. Impressively, the composite of TiO2 nanoparticles/TPA synthesized using H2O as solvent under hydrothermal condition exhibits the highest photocatalytic H2 activity among the studied materials, with a photocatalytic H2 production rate of 6.38 mmol g−1 h−1, which is approximately 7.5‐fold higher than pure TiO2 (Degussa, P25) and prominent apparent quantum efficiency (AQE) of 65 % at 365 nm. Furthermore, the mechanism of boosted photocatalytic H2 production is discussed. [ABSTRACT FROM AUTHOR]

As an alternative to the investigation of photocatalysts, it is a potential approach to enhance the photocatalytic performance of the novel photocatalytic reactor by optimizing its geometric structure and reaction conditions. In this work, five different honeycomb photocatalytic reactors with a deflector and a porous airflow distribution plate were designed and a numerical simulation was performed based on computational fluid dynamics (CFD). The simulation results showed that a huge vortex appeared near the entrance of the original model and the velocity distribution inside the reactor was non-uniform, whereas these shortcomings could be effectively overcome when using the 45° deflector model (S-4) compared to the other models. Compared to S-1, the photocatalytic conversion rate of formaldehyde for S-4 was boosted by 7.29% at a flow velocity of 0.04 m s−1. In addition, it was found that the photocatalytic conversion rate of formaldehyde increased from 55.45 to 94.73% when the velocity decreased from 0.04 to 0.01 m s−1, and the photocatalytic removal rate of formaldehyde decreased from 94.73 to 70.05% as the relative humidity varied from 20 to 70%. Furthermore, when the irradiance increased from 45 to 265 mW cm−2, the photocatalytic conversion rate of formaldehyde improved by 10.78%. Overall, this work contributes to the design of the novel honeycomb reactor to acquire the optimized construction of the photocatalytic reactor. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the channel estimation and signal‐to‐noise ratio (SNR) estimation technique of single‐carrier frequency domain equalization (SC‐FDE) system under low SNR in aeronautical multipath channel are studied, a SNR estimation algorithm which is easy to implement in engineering and an improved LS channel estimation algorithm based on Kalman filter using minimum error entropy (MEE‐KF) are proposed. This paper first introduces the SC‐FDE system and introduces the principle of MEE‐KF, and then, the channel estimation flow based on MEE‐KF is obtained by combining it with the traditional LS channel estimation algorithm, which makes the estimation results perform better. Simulation results show that after getting more accurate noise variance, the channel estimation results can better follow the changes of the channel after MEE‐KF processing, so as to resist the doppler frequency offset effect and make the channel estimation results more accurate, that is the channel response results of the data part can be closer to the real situation, so that the communication performance of SC‐FDE system has also been greatly improved. [ABSTRACT FROM AUTHOR]

Introducing piezoelectric materials with the built-in electric field caused by mechanical force has been confirmed as an effective strategy to boost the separation efficiency of photoexcited charge carriers that determines the photocatalytic performance. In this study, we introduced Bi4Ti3O12 with superior piezoelectric properties into BiVO4–Bi4V2O10 materials to synthesize a 2D Bi4Ti3O12–BiVO4–Bi4V2O10 photocatalyst via a facile hydrothermal method. Compared with bare BiVO4, the Bi4Ti3O12–BiVO4–Bi4V2O10 piezo-photocatalytic activity towards Cr(VI) removal and oxygen evolution is boosted remarkably under both illumination and ultrasound treatments. The promoted photocatalytic activity can be ascribed to the accelerated photoexcited carrier separation efficiency driven by the polarization electric field and the synergy effect in the heterostructure. This work provides a simple and sustainable strategy for the design and development of piezo-photocatalysts with high photoredox activity capacity. [ABSTRACT FROM AUTHOR]

A novel feature extraction method based on the energy cumulant of Choi-Williams distribution has been proposed, which copes with the complex electromagnetic environment and varied signal styles. The energy cumulant of Choi-Williams distribution has been calculated from the accumulations of each frequency sample value with different time samples. Preceding this procedure, the time frequency distribution via Choi-Williams distribution has been processed through base noise reduction. Henceforth, a simulation analysis based on the discriminability and recognition effect of the proposed features in a low SNR environment has been carried out. In the discriminability experiment, the kernel fuzzy C-means clustering algorithm has been employed for classifying the radar pulse modulated radiation source signals. In the recognition effect analysis, the deep belief network has been proposed to employ the input feature vectors for training to achieve the radar emitter recognition and classification. Simulation results demonstrate that the proposed feature extraction method is feasible and robust in radar emitter classification and recognition even at a low SNR. [ABSTRACT FROM AUTHOR]

The development of alkaline polymer electrolyte fuel cells and alkaline water electrolysis requires nonprecious metal catalysts for the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). Herein, it is reported a phase‐separated Mo–Ni alloy (PS‐MoNi) that is composed of Mo metal and embedded Ni metal nanoparticles. The PS‐MoNi shows excellent hydrogen electrode activity with a high exchange current density (−4.883 mA cm−2), which is comparable to the reported highest value for non‐noble catalysts. Moreover, the amorphous phase‐separated Mo–Ni alloy has better structural and electrochemical stability than the intermetallic compound Mo–Ni alloy (IC‐MoNi). The breakdown potential of PS‐MoNi is as high as 0.32 V, which is much higher than that of reported IC‐MoNi. The X‐ray absorption near edge structure (XANES) and density functional theory (DFT) calculations indicate the electrons transfer from Mo to Ni for PS‐MoNi, leading to suitable adsorption free energies of H* (ΔGH*) on the surface of Mo. This means that the electron density modulation of Mo metal by embedded Ni metal nanoparticles can produce excellent HOR and HER performance. [ABSTRACT FROM AUTHOR]

TiO2 nanotube-based photocatalytic concrete paving block was prepared, and its mechanical properties, including compressive strength and abrasion resistance, as well as photocatalytic removal of NO, were investigated. Results indicate that the compressive strength and abrasion resistance of photocatalytic concrete paving block were obviously reinforced by TiO2 nanotubes compared with TiO2 nanoparticles, which might derive from the enhanced binding force between TiO2 nanotubes and calcium–silicate–hydrate (C–S–H) gel derived from the cement hydration. Moreover, the TiO2 nanotube-based photocatalytic concrete paving block shows the best photocatalytic removal of NO among the as-prepared samples, which might result from the enhanced adsorption property for NO gas over TiO2 nanotubes, and little change of NO conversion was found before and after polishing. Overall, TiO2 nanotubes not only contribute to the reinforcement of mechanical properties of the concrete block, but also dedicated to the enhancement of photocatalytic performance for NO purification. [ABSTRACT FROM AUTHOR]

BACKGROUND: A leach‐bed reactor (LBR) with leachate recirculation is a suitable technology for lignocellulosic biomass anaerobic digestion. In this study, the effect of percolate reflux strategies (continuous recirculation and intermittent recirculation) on methane production from Pennisetum hybrid, a type of energy crop, was investigated using a two‐layered LBR. RESULTS: Compared to a solid‐state anaerobic digestion batch test, LBRs with percolate recirculation provide a stable process with a short lag phase by avoiding inhibition of volatile fatty acid accumulation and inoculation effect. The results also indicated that continuous reflux led to a lower accumulative methane yield (56.20 L kg−1 VS) compared to intermittent reflux (78.50 L kg−1 VS), resulting from washing effect and poorer distribution on the lower layer. According to microbial analysis, Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes were the most predominant bacterial phyla in each LBR test sample and aceticlastic methanogen (at least >55%) plays a predominant role for methane production in all samples. CONCLUSIONS: The results indicate that leachate recirculation could provide stable conditions for methane yield; however, two‐layer reactor designs which cannot guarantee the desired distribution in the lower layer result in a low methane yield. Suitable design of LBRs to maintain a well‐distributed reflux leachate should be further investigated. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Highly ordered TiO2 nanotube arrays (TiO2 NTs) were prepared by anodic oxidizing method on a surface of Ti substrate. Fabrication of nitrogen-doped TiO2 nanotube arrays (N-TiO2 NTs) was carried out by immersion in ammonia solution. CdS nanoparticles loaded N-doped TiO2 nanotube arrays (CdS/N-TiO2 NTs) were obtained by successive ionic layer adsorption and reaction (SILAR) technique. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL) emission spectra and ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy (DRS). The results indicate that the TiO2 nanotube diameter and wall thickness are 100 nm to 120 nm and 20 nm to 30 nm, respectively. Moreover, the morphology and structure of the highly ordered TiO2 NTs are not affected by N-doping. Furthermore, CdS nanoparticles are evenly distributed on the surface of TiO2 NTs. Finally, the photocatalytic activity of CdS/N-TiO2 NTs was evaluated by degradation of MO under visible-light irradiation. Compared with TiO2 NTs, N-TiO2 NTs, CdS/N-TiO2 NTs exhibited enhanced photocatalytic properties, and the highest degradation rate of CdS/N-TiO2NTs could reach 97.6 % after 90 min of irradiation. [ABSTRACT FROM AUTHOR]

A new two-photon fluorescent probe (MCN) for viscosity imaging was developed based on a 6-substituted quinoline framework. MCN showed an excellent “off–on” fluorescence response (ca. 90-fold enhancement) with viscosity increasing in the glycerol–water viscosity system. MCN showed great sensitivity to viscosity (R2 = 0.98, x = 0.65), which gave rise to cell imaging for micro-viscosity or real-time cell imaging during apoptosis with low cytotoxicity under two-photon excitation (λex = 800 nm). Fluorescence lifetime imaging (FLIM) of living HeLa cells stained with MCN revealed that the intracellular average viscosity value was 73.45 ± 21.55 cP in cytosol. Imaging in living tissue slices indicated that MCN can work in deep tissue (∼130 μM) under two-photon excitation. Moreover, MCN also showed the capacity for in vivo imaging viscosity in zebrafish with obvious fluorescence emission. [ABSTRACT FROM AUTHOR]

Ag3PO4 triangular prism was synthesized by a facile chemical precipitation approach by simply adjusting external ultrasonic condition. The as-synthesized Ag3PO4 triangular prism was characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectra, and ultraviolet-visible diffuse reflectance (UV-vis DRS) absorption spectra. The photocatalytic activity of Ag3PO4 triangular prism was evaluated by photodegradation of organic methylene blue (MB), rhodamine B (RhB), and phenol under visible light irradiation. Results showed that Ag3PO4 triangular prism exhibited higher photocatalytic activity than N-doped TiO2 and commercial TiO2 (P25) under visible light irradiation. [ABSTRACT FROM AUTHOR]

CaAl2O4:Eu2+, Nd3+ nanofibers were prepared via the electrospinning process by using core–sheath CaAl2O4:Eu2+, Nd3+/carbon nanofibers as templates, combined with a subsequent annealing treatment. The obtained nanofibers are smooth with tunable diameters ranging from 50 to 120 nm by simply changing the ratio of inorganic precursors to solvent. The intermediate state is composed of hollow CaAl2O4:Eu2+, Nd3+@carbon nanofibers. The formation process, luminescent properties and long lasting performance are investigated. This facile method for synthesizing nanofibers may have potential applications in the field of in vivo imaging and coatings for long lasting phosphors. [ABSTRACT FROM AUTHOR]

The BiOCl/ Ag3 PO4 composites have been prepared via a facile and reproducible route. In the composite, Ag3 PO4 particles are deposited on the surface of plates of BiOCl. Among the as-prepared samples, the ultraviolet ( UV) and visible light photocatalytic reaction rates of BiOCl/ Ag3 PO4 composite with the ratio of 1:0.1 are about 4.4 times and 4.5 times than that of pure BiOCl, respectively. Overall, the BiOCl/ Ag3 PO4 composites not only show highly enhanced visible light photocatalytic activity but also exhibit highly improved UV photocatalytic activity, which could find enormous potential application in addressing environmental protection issues utilizing solar energy effectively. [ABSTRACT FROM AUTHOR]

C-doped, Mo-doped, and (Mo, C)-codoped TiO2 photocatalysts were prepared by a sol-gel process. The photocatalytic activity was evaluated by the photocatalytic degradation of methyl orange (MO) under simulated solar irradiation. Results indicated that both monodoped and codoped TiO2 exhibited better visible light absorption behavior and narrower energy gap than pure TiO2, and codoped TiO2 showed a slightly higher adsorption property in the dark because of higher Brunauer-Emmett-Teller-specific surface area. The photocatalytic activity of monodoped TiO2 was also enhanced, and the (0.04% Mo, C)-codoped sample had the best photocatalytic activity for degrading MO among all of the samples. The reason can be ascribed to the synergistic effect due to Mo and C doping. Furthermore, the transfer pathways of photoinduced carriers and photocatalytic reaction mechanism of (Mo, C)-codoped TiO2 was first investigated. [ABSTRACT FROM AUTHOR]

The multi-walled ( B, N)-codoped titanate nanotubes ( TNTs) have been prepared via a simple hydrothermal route. Such ( B, N)-codoped TNTs showed a decrease in band gap energy as compared with the undoped TNTs. The effect of the doping amounts of B and N on the photocatalytic activity of TNTs was studied. Among the as-prepared samples, (1% B, 1% N)-codoped TNTs exhibited the best photocatalytic activity for methyl orange decomposition under Ultraviolet-Visible ( UV-Vis) light irradiation. The photocatalytic activity of (1% B, 1% N)-codoped TNTs is twice as high as that of the undoped TNTs. [ABSTRACT FROM AUTHOR]