Preparation of 2D square-like Bi2S3-BiOCl heterostructures with enhanced visible light-driven photocatalytic performance for dye pollutant degradation

A series of Bi2 S3-BiOCI composites with two-dimensional(2 D) square-like structures were prepared via a two-step anion exchange route.X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and diffuse reflectance spectra(DRS)were used to investigate the properties of the as-prepared Bi_2 S_3-BiOCI heterostructures. The coupling of BiOCl and Bi_2 S_3 induced enhanced photoabsorption efficiency and bandgap narrowing. A reactive brilliant red X-3 B dye was used as a contaminant to test the photocatalytic activity of the obtained Bi_2 S_3-BiOCl samples under visible light irradiation. The sample Bi_2 S_3-BiOCl with a mass ratio of 8:4 exhibited the highest photodegradation efficiency, which was six times higher than that of pure BiOCl. In addition, a mechanism for the enhancement of photocatalytic activity is proposed.

Visible light-driven oxidant-free dehydrogenation of alcohols in water using porous ultrathin g-C_(3)N_(4)nanosheets

Graphitic carbon nitride(g-C_(3)N_(4)) is a fascinating photocatalyst for solar energy utilization in photo-catalysis.Nevertheless,it often suffers from moderate photo-catalytic activity due to its low specific surface area and fast recombination rate of photogenerated electrons upon photo-excitation.Herein,we overcome the bottlenecks by constructing a porous g-C_(3)N_(4) nanosheet(PCNS)through a simple thermal oxidation etching method.Benefited from its porous layer structure,the obtained PCNS exhibits large specific surface area,efficient separation of photogenerated charge carriers,as well as high exposure of active sites.As a result,it is robust and universal in visible light-driven dehydrogenation of alcohols in water under oxidant-free condition.Almost quantitative yields(>99%)of various valuable carbonyl compounds were obtained over PCNS,while bulk g-C_(3)N_(4) was far less efficient.Moreover,the photo-catalyst was highly stable and could be facilely recovered from the aqueous system for efficient reuse.The easy preparation and excellent performance made PCNS a promising and competitive photocatalyst for the solar applications.

Redox active ionic liquid as efficient mediator and solvent for visible light-driven B_(12) catalytic reactions

The redox active ionic liquid, 1-ethyl-4-(methoxycarbonyl)pyridinium bis(trifluoromethanesulfonyl)amide(RIL), was synthesized from its iodide form by an anion exchange reaction of Li(NTf_2) with viscos liquid(η= 122 cP at 25C) and characterized by NMR, IR, and elemental analysis. The compound showed reversible redox couples at -0.65 V and -1.48 V vs. Ag/AgCl and worked as an electron mediator in the B_(12) complex/[Ru(bpy)_3]Cl_2 photosensitizer catalytic system under visible light irradiation. The catalytic efficiency in the RIL was higher than those in DMF, MeOH, and the redox inactive ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)amide.

Synthesis of S-doped Sb_2O_3 Visible Light-driven Photocatalyst and Its Facets-dependent Performance for the Degradation of Methyl Orange

S-doped Sb_2O_3 nanocrystals were synthesized using SbCl3 and thioacetamide（TAA） as starting materials by a hydrothermal method and the effects of TAA dosage on the composition and properties of resultant nanocrystals were determined.Their photocatalytic performance was evaluated using the degradation of methyl orange（MO） as a model reaction.The results suggest that TAA dosage can affect the preferential growth direction of Sb_2O_3,and further influences its photocatalytic activity.S doping can extend the optical absorption edge of Sb_2O_3 to the visible light religion,and thus endows its ability to photocatalyze the degradation of MO under visible light illumination.Based on these results,the correlations between the photocatalytic activity of S-doped Sb_2O_3 and the ratio between exposed facets,specific surface area and crystallographic defects were discussed.

Visible light-driven oxidation of non-native substrate by laccase attached on Ru-based metal-organic frameworks

Light-induced electron transfer can broaden the substrate range of metalloenzyme.However,the efficiency of photo-enzyme coupling is limited by the poor combination of photosensitizer or photocatalyst with enzyme.Herein,we prepared the nano-photocatalyst MIL-125-NH_(2)@Ru(bpy)by in site embedding ruthenium pyridine-diimine complex[Ru(bpy)_(3)^(2+)into metal organic frameworks MIL-125-NH_(2)and associated it with multicopper oxidase(MCO)laccase.Compared to[Ru(bpy)_(3)]^(2+),the coupling efficiency of MIL-125-NH_(2)@Ru(bpy)_(3)for enzymatic oxygen reduction increased by 35.7%.A series of characterizations confirmed that the amino group of laccase formed chemical bonds with the surface defects or hydrophobic groups of MIL-125-NH_(2)@Ru(bpy)_(3).Consequently,the tight binding accelerated the quenching process and electron transfer between laccase and the immobilized ruthenium pyridine-diimine complex.This work would open an avenue for the synthesis of MOFs photocatalyst towards photo-enzyme coupling.

Infrared and Visible Image Fusion Based on Res2Net-Transformer Automatic Encoding and Decoding

A novel image fusion network framework with an autonomous encoder and decoder is suggested to increase thevisual impression of fused images by improving the quality of infrared and visible light picture fusion. The networkcomprises an encoder module, fusion layer, decoder module, and edge improvementmodule. The encoder moduleutilizes an enhanced Inception module for shallow feature extraction, then combines Res2Net and Transformerto achieve deep-level co-extraction of local and global features from the original picture. An edge enhancementmodule (EEM) is created to extract significant edge features. A modal maximum difference fusion strategy isintroduced to enhance the adaptive representation of information in various regions of the source image, therebyenhancing the contrast of the fused image. The encoder and the EEM module extract features, which are thencombined in the fusion layer to create a fused picture using the decoder. Three datasets were chosen to test thealgorithmproposed in this paper. The results of the experiments demonstrate that the network effectively preservesbackground and detail information in both infrared and visible images, yielding superior outcomes in subjectiveand objective evaluations.

CAEFusion: A New Convolutional Autoencoder-Based Infrared and Visible Light Image Fusion Algorithm

To address the issues of incomplete information,blurred details,loss of details,and insufficient contrast in infrared and visible image fusion,an image fusion algorithm based on a convolutional autoencoder is proposed.The region attention module is meant to extract the background feature map based on the distinct properties of the background feature map and the detail feature map.A multi-scale convolution attention module is suggested to enhance the communication of feature information.At the same time,the feature transformation module is introduced to learn more robust feature representations,aiming to preserve the integrity of image information.This study uses three available datasets from TNO,FLIR,and NIR to perform thorough quantitative and qualitative trials with five additional algorithms.The methods are assessed based on four indicators:information entropy(EN),standard deviation(SD),spatial frequency(SF),and average gradient(AG).Object detection experiments were done on the M3FD dataset to further verify the algorithm’s performance in comparison with five other algorithms.The algorithm’s accuracy was evaluated using the mean average precision at a threshold of 0.5(mAP@0.5)index.Comprehensive experimental findings show that CAEFusion performs well in subjective visual and objective evaluation criteria and has promising potential in downstream object detection tasks.

Development of D_α band symmetrical visible optical diagnostic for boundary reconstruction on EAST tokamak

To investigate the potential of utilizing visible spectral imaging for controlling the plasma boundary shape during stable operation of plasma in future tokamak, a D_α band symmetric visible light diagnostic system was designed and implemented on the Experimental Advanced Superconducting Tokamak(EAST). This system leverages two symmetric optics for joint plasma imaging. The optical system exhibits a spatial resolution less than 2 mm at the poloidal cross-section, distortion within the field of view below 10%, and relative illumination of 91%.The high-quality images obtained enable clear observation of both the plasma boundary position and the characteristics of components within the vacuum vessel. Following system calibration and coordinate transformation, the image coordinate boundary features are mapped to the tokamak coordinate system. Utilizing this system, the plasma boundary was reconstructed, and the resulting representation showed alignment with the EFIT(Equilibrium Fitting) results. This underscores the system's superior performance in boundary reconstruction applications and provides a diagnostic foundation for boundary shape control based on visible spectral imaging.

Deep learning-assisted common temperature measurement based on visible light imaging

Real-time,contact-free temperature monitoring of low to medium range(30℃-150℃)has been extensively used in industry and agriculture,which is usually realized by costly infrared temperature detection methods.This paper proposes an alternative approach of extracting temperature information in real time from the visible light images of the monitoring target using a convolutional neural network(CNN).A mean-square error of<1.119℃was reached in the temperature measurements of low to medium range using the CNN and the visible light images.Imaging angle and imaging distance do not affect the temperature detection using visible optical images by the CNN.Moreover,the CNN has a certain illuminance generalization ability capable of detection temperature information from the images which were collected under different illuminance and were not used for training.Compared to the conventional machine learning algorithms mentioned in the recent literatures,this real-time,contact-free temperature measurement approach that does not require any further image processing operations facilitates temperature monitoring applications in the industrial and civil fields.

An organic visible-photocatalytic-adsorbence mechanism to high-efficient removal of heavy metal antimony ions

Purification of emerging heavy metal antimony contaminated water based on advanced ingenious strategies.An activated modified coconut shell charcoal(CSC)was synthesized and evaluated as a substrate-supported loaded organic photovoltaic material,PM6:PYIT:PM6-b-PYIT,to prepare a surprisingly highly efficient,stable,environmentally friendly,and recyclable organic photocatalyst(CSC–N–P.P.P),which showed excellent effects on the simultaneous removal of Sb(Ⅲ)and Sb(Ⅴ).The removal efficiency of CSC-N-P.P.P on Sb(Ⅲ)and Sb(Ⅴ)reached an amazing 99.9%in quite a short duration of 15 min.At the same time,under ppb level and indoor visible light(~1 W m^(2)),it can be treated to meet the drinking water standards set by the European Union and the U.S.National Environmental Protection Agency in 5 min,and even after 25 cycles of recycling,the efficiency is still maintained at about 80%,in addition to the removal of As(Ⅲ),Cd(Ⅱ),Cr(Ⅵ),and Pb(Ⅱ)can also be realized.The catalyst not only solves the problems of low reuse rate,difficult structure adjustment and high energy consumption of traditional photocatalysts but also has strong applicability and practical significance.The pioneering approach provides a much-needed solution strategy for removing highly toxic heavy metal antimony pollution from the environment.

A CSMA/CA based MAC protocol for hybrid Power-line/Visible-light communication networks:Design and analysis

Hybrid Power-line/Visible-light Communication(HPVC)network has been one of the most promising Cooperative Communication(CC)technologies for constructing Smart Home due to its superior communication reliability and hardware efficiency.Current research on HPVC networks focuses on the performance analysis and optimization of the Physical(PHY)layer,where the Power Line Communication(PLC)component only serves as the backbone to provide power to light Emitting Diode(LED)devices.So designing a Media Access Control(MAC)protocol remains a great challenge because it allows both PLC and Visible Light Communication(VLC)components to operate data transmission,i.e.,to achieve a true HPVC network CC.To solve this problem,we propose a new HPC network MAC protocol(HPVC MAC)based on Carrier Sense Multiple Access/Collision Avoidance(CSMA/CA)by combining IEEE 802.15.7 and IEEE 1901 standards.Firstly,we add an Additional Assistance(AA)layer to provide the channel selection strategies for sensor stations,so that they can complete data transmission on the selected channel via the specified CSMA/CA mechanism,respectively.Based on this,we give a detailed working principle of the HPVC MAC,followed by the construction of a joint analytical model for mathematicalmathematical validation of the HPVC MAC.In the modeling process,the impacts of PHY layer settings(including channel fading types and additive noise feature),CSMA/CA mechanisms of 802.15.7 and 1901,and practical configurations(such as traffic rate,transit buffer size)are comprehensively taken into consideration.Moreover,we prove the proposed analytical model has the solvability.Finally,through extensive simulations,we characterize the HPVC MAC performance under different system parameters and verify the correctness of the corresponding analytical model with an average error rate of 4.62%between the simulation and analytical results.

High-resolution visible imaging with piezoelectric deformable secondary mirror: experimental results at the 1.8-m adaptive telescope

Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.

Comparing simulated and experimental spectral line splitting in visible spectroscopy diagnostics in the HL-2A tokamak

We established the passive-visible spectroscopy diagnostics(P-VSD)and active-VSD(A-VSD)spectral splitting models for the HL-2A tokamak.Spectral splitting due to the influence of electromagnetic fields on the spectra in VSD is studied.Zeeman splitting induced by the magnetic field(B)is used to distinguish reflected light overlap in the divertor for P-VSD.Stark splitting caused by the Lorentz electric field(E_(Lorentz))from the neutral beam injection particle’s interaction with the magnetic field(V_(beam)×B)is used to measure the safety factor q profile for A-VSD.We give a comparison and error analysis by fitting the experimental spectra with the simulation results.The distinguishing of edge(scrape-off layer and divertor)hydrogen/deuterium spectral lines and the q profile derived from the spectra provides a reference for HL-2M VSD.

Channel Capacity and Power Allocation of MIMO Visible Light Communication System

In this paper,the channel capacity of the multiple-input multiple-output(MIMO)visible light communication(VLC)system is investigated under the peak,average optical and electrical power constraints.Finding the channel capacity of MIMO VLC is shown to be a mixed integer programming problem.To address this open problem,we propose an inexact gradient projection method to find the channel capacity-achieving discrete input distribution and the channel capacity of MIMO VLC.Also we derive both upper and lower bounds of the capacity of MIMO VLC with the closed-form expressions.Furthermore,by considering practical discrete constellation inputs,we develop the optimal power allocation scheme to maximize transmission rate of MIMO VLC system.Simulation results show that more discrete points are needed to achieve the channel capacity as SNR increases.Both the upper and lower bounds of channel capacity are tight at low SNR region.In addition,comparing the equal power allocation,the proposed power allocation scheme can significantly increase the rate for the low-order modulation inputs.

Facile one-pot synthesis of a BiOBr/Bi_(2)WO_(6) heterojunction with enhanced visible-light photocatalytic activity for tetracycline degradation

Photocatalytic removal of tetracycline(TC)from the wastewater is of great value in the chemical and environmental engineering field.Here,we introduced a facile one-step method for the synthesis of BiOBr/Bi2WO6 heterojunctions by using cheap CTAB as the Br source.We showed the possibility of our method to fine-tune the content of BiOBr in the produced BiOBr/Bi2WO6 by simply changing the dosage of cetyltrimethylammonium bromide(CTAB),providing a platform for the delicate tuning of the visiblelight absorbance ability of the composites.With a suitable heterojunction structure of BiOBr/Bi2WO6-0.2,it exhibited an ultrarapid photocatalytic activity towards TC(20 mg
L^(-1)),with a competitive removal efficiency of 88.1%within 60 min and an ultrahigh removal rate of 0.0349 min^(-1).It could also be robustly recycled for at least 5 cycles with slight removal efficiency loss.We demonstrated that this exciting photocatalytic performance was due to the highly decreased recombination of photoinduced electrons and holes on our composites by constructing this heterojunction structure,and the resulting
OH and
O^(-)_(2)contributed to the effective degradation of TC to CO_(2).

Visible light-driven organic photochemical synthesis in China

In recent years, visible light-driven organic photochemical synthesis has attracted wide research interest from academic and industrial communities due to its features of green and sustainable chemistry. In this flourishing area, Chinese chemists have devoted great efforts to different aspects of synthetic chemistry. This review will summarize their representative work according to the following categories: C–H functionalization, synthesis of aromatic aza-heterocycles, asymmetric organic photochemical synthesis, transformations of small molecules and biomolecule-compatible reactions.

Template-free large-scale synthesis of g-C3N4 microtubes for enhanced visible light-driven photocatalytic H2 production

A template-free hydrothermal-assisted thermal polymerization method has been developed for the large-scale synthesis of one-dimensional （1D） graphitic carbon nitride （g-C3N4） microtubes. The g-C3N4 microtubes were obtained by simple thermal polymerization of melamine-cyanuric acid complex microrods under N2 atmosphere, which were synthesized by hydrothermal treatment of melamine solution at 180℃ for 24 h. The as-obtained g-C3N4 microtubes exhibited a large surface area and a unique one-dimensional tubular structure, which provided abundant active sites for proton reduction and also facilitated the electron transfer processes. As such, the g-C3N4 microtubes showed enhanced photocatalytic H2 production activity in lactic acid aqueous solutions under visible light irradiation （A 〉 420 nm）, which was - 3.1 times higher than that of bulk g-C3N4 prepared by direct thermal polymerization of the melamine precursor under the same calcination conditions.

A visible light-driven plasmonic photocatalyst

We demonstrate a bottom-up approach to fabricating a visible light-driven titania photocatalyst device bearing an embeddedtwo-dimensional (2D) array of gold nanoparticles (AuNPs) as a near-field light-generating layer. The device is a layered structureprepared by depositing a 2D array of AuNPs on a transparent conductive substrate (10 nm indium tin oxide (ITO) layer on quartz),coating the 2D array of AuNPs with a monolayer of trimethoxyoctylsilane (TMOS), and depositing titania nanocrystals on the anchoringmolecule (TMOS) layer. The visible light activity of the device was tested using photocatalytic degradation of methylene blue (MB) byilluminating the device with visible light (700 nm light) and ultraviolet (UV) light (250–380 nm). The localized surface plasmonresonance peak of the 36 nm AuNP 2D array is around 700 nm with a full-width at half-maximum of 350 nm. In comparison with othercontrol samples, the device showed the highest photocatalytic activity with visible irradiation, which was 1.7 times higher than that oftitania with UV irradiation. The origin of the visible light activity was confirmed by both quadratic incident light power dependency andaction spectrum to be plasmon-induced (near-field enhancement by AuNPs) two-photon absorption.

Characterization of retinal ganglion cell damage at single axon bundle level in mice by visible-light optical coherence tomography fibergraphy

Retinal ganglion cells(RGCs)receive synaptic inputs through their dendritic trees in the inner plexiform layer(IPL)and convey the visual information via their axons which form the optic nerve to the brain(Sanes and Masland,2015).In glaucoma,RGCs and their axons degenerate and die,leading to irreversible vision loss and eventually blindness if left untreated(Quigley,2016).

HY-PC:Enabling Consistent Positioning and Communication Using Visible Light

Visible light(VL)plays an important role in achieving high-precision positioning and low bit error radio(BER)data communication.However,most VL-based systems can not achieve positioning and communication,simultaneously.There are two problems:1)the hybrid systems are difficult to extract distinguishable positioning beacon features without affecting communication performance,2)in the hybrid systems,the lost data bits in the inter-frame gap(IFG)are hard to recover,which affects positioning and communication performance.Therefore,in this article,we propose a novel VL-based hybrid positioning and communication system,named HY-PC system,to solve the above problems.First,we propose the robust T-W mapping for recognizing specific Light Emitting Diodes(LEDs),which can provide stable LED recognition accuracy without adding extra beacon data and does not decrease the communication rate.Furthermore,we also propose the novel linear block coding and bit interleaving mechanism,which can recover the lost data bits in the IFG and improve data communication performance.Finally,we use commercial off-the-shelf devices to implement our HY-PC system,extensive experimental results show that our HY-PC system can achieve consistent high-precision positioning and low-BER data communication,simultaneously.