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- 2018
- imgae sensor
- internet of things
- drone
- visible light ID
- Signal-to-Noise Ratio (SNR)
- Infinite Gain Multiple Feedback (IGMF)
- Visible Light Communications (VLC)
- LED
- Trans-Impedance Amplifier (TIA)
- Optoelectronic Information Science and Engineering
- Tohoku University
- University of Northumbria
- University of Huddersfield
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Three-Mode Modulation Electrochromic Device with High Energy Efficiency for Windows of Buildings Located in Continental Climatic Regions
摘要： A sustainable use of energy in buildings demands energy-efficient windows. A new design concept for electrochromic (EC) smart windows, easy to implement at the industrial level, is introduced here. It enables simultaneous control of visible and near-infrared (NIR) solar radiation, thus contributing to reduce heating and cooling loads especially in buildings located in areas experiencing wide daily temperature ranges. The EC device comprises amorphous indium zinc oxide, a conducting oxide transparent in the visible and NIR spectral regions, as nonactive layer, and a sol–gel protonic ionic liquid-doped di-ureasil electrolyte displaying high transparency and proton conductivity. The device offers three voltage-operated modes: bright hot (+3.0 V: transmittances of 70/83% at 555/1000 nm), semi-bright warm (?2.0 V: transmittances of 37/35% at 555/1000 nm), and dark cold (?2.5 V: transmittances of 6/4% at 555/1000 nm). Its main figures of merit are: high switching efficiency (transmittance variations of 64/79% at 555/1000 nm), high optical density modulation (1.1/1.3 at 555/1000 nm), high optical contrast ratio in the visible region (lightness variation of ≈43), good cycling stability, and unprecedented coloration efficiency (?12538/?14818 cm2 C?1 and +2901/+3428 cm2 C?1 at 555/1000 nm), outstanding optical memory (transmittance variation loss of only 24% more than 4 months after coloration), and self-healing ability following mechanical stress.
关键词： di-ureasil hybrid,N-butylimidazolium trifluoromethanesulfonate,visible- and NIR-controlled electrochromic devices,amorphous indium zinc oxide,energy-efficient smart windows for buildings
更新于2025-09-10 09:29:36
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Metal-free Semiconductor Photocatalysis for sp2 C-H Functionalization with Molecular Oxygen
摘要： Designing metal-free catalysts for solar energy conversion is a long-standing challenge in semiconductor photoredox catalysis (SPC). With visible-light-responsive hexagonal boron carbon nitride (h-BCN) as a non-metal photocatalyst, this system affords C–H/N–H coupling products with broad substitution tolerance and high efficiency with molecular oxygen as the terminal oxidant. The catalyst exhibits remarkable performance for the selective C-H functionalization of electron-rich arenes to C-N products (yields up to 95%) and good stability (6 recycles). Both nitrogen heteroarenes and amine salts are competent coupling nucleophiles. Mechanically, the reactive oxygen species are superoxide anion radical (O2??) and H2O2, which are proved by electron spin resonance (ESR) data, KI-starch, and control experiments. In addition, kinetic isotope effect (KIE) experiments indicate that C–H bond cleavage is not involved in the rate limiting step. This semiconductor-based photoredox system allows for C–H amination free of any metals, ligands, strong oxidants, and additives. It provides a complementary avenue to C–H functionalizations and enables synthetic applications efficiently in a sustainable manner.
关键词： Radical,Semiconductor Photoredox Catalysis,Heterogeneous Catalysis,Visible Light,C-H Fuctionalizaition
更新于2025-09-10 09:29:36
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[Topics in Organometallic Chemistry] || Functionalization of C(sp2)–H Bonds of Arenes and Heteroarenes Assisted by Photoredox Catalysts for the C–C Bond Formation
摘要： The formation of C–C bonds from arenes and heteroarenes through transition metal-catalyzed C–H bond functionalizations is one of the major achievements of these last decades. It is now possible to perform such transformations under mild reaction conditions with the help of visible light photocatalysis leading to eco-friendly and safer process to build organic molecules or materials. This chapter will focus on photoredox catalysis which involves a C(sp2)–H bond functionalization step for the formation of C(sp2)–C bonds [i.e., direct arylations and (per?uoro)alkylations] and will show how this hot topic contributes to the development of green chemistry.
关键词： MLTC photoredox catalysis,C(sp2)–H bond,Visible light,C–C bond formation
更新于2025-09-10 09:29:36
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Water-Dispersed Conjugated Polyelectrolyte for Visible-Light Hydrogen Production
摘要： Conjugated polymer-based photocatalysts have shown great potential in H2 production via water splitting, but an intrinsic drawback of conventional hydrophobic polymer photocatalysts is their poor wettability and relatively large particle size in aqueous media, which is favorable for charge recombination with limited interfacial reaction efficiency. Herein, a well-dispersed organic water reduction system using cationic conjugated polyelectrolyte as the photocatalyst has been reported for the first time. In comparison to a model polymer (PFBT) bearing the same conjugated backbone, the polyelectrolyte exhibits significantly enhanced photocatalytic efficiency due to the extended light absorption and improved charge separation of the polymer aggregates.
关键词： conjugated polyelectrolyte,water-dispersed,visible-light hydrogen production
更新于2025-09-10 09:29:36
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A novel poly(triazine imide) hollow tube/ZnO heterojunction for tetracycline hydrochloride degradation under visible light irradiation
摘要： A novel poly(triazine imide) hollow tube (PTI)/ZnO heterojunction was prepared by a molten salts method. The photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy, respectively. The results showed the ZnO nanoparticles were successfully coupled into the PTI hollow tube to form PTI/ZnO heterojunction. The degradation of tetracycline hydrochloride (TC) under visible light irradiation was used to evaluate the activity of photocatalyst. The PTI/ZnO-6 wt% heterojunction exhibits the highest photocatalytic activity, which can degrade almost all TC within 90 min. The kinetic constant of degradation reaction with PTI/ZnO-6 wt% heterojunction (0.034 min?1) is about 5 times as high as that of the PTI (0.0070 min?1). A possible photocatalytic mechanism for heterojunction according to the energy-band theory was proposed.
关键词： ZnO,Tetracycline hydrochloride,Visible light photocatalytic,Poly(triazine imide),Hollow tube
更新于2025-09-10 09:29:36
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Robust and accurate measurements of gold nanoparticle concentrations using UV-visible spectrophotometry
摘要： This paper provides an empirical formula to calculate the extinction efficiencies of gold nanoparticles over the size range 1–1000 nm in fluids with refractive indexes which extend from n = 1 to n = 1.62. The formula contains a shape factor to account for nonspherical particles and aggregates. The empirical curves are fitted to values calculated from accurate Mie and T-Matrix theory and confirm previous descriptions which are restricted to nearly spherical particles in water of diameter between 5 and 100 nm. This paper demonstrates that these previous descriptions will be in error for fluids other than water and for nonspherical particles greater than 100 nm in size. An empirical description is provided which matches calculated values to within a few percent across most of the range. The description also matches experimental data to within the standard relative error, currently 5% at best, using other methods which directly measure the particle concentration. These extinction efficiencies can be used to validate the concentration of gold nanoparticles in a wide range of situations to support the drive for reproducibility in nanoparticle research.
关键词： Mie theory,extinction efficiencies,gold nanoparticles,T-Matrix theory,UV-visible spectrophotometry
更新于2025-09-10 09:29:36
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[ACM Press the 17th ACM Workshop - Redmond, WA, USA (2018.11.15-2018.11.16)] Proceedings of the 17th ACM Workshop on Hot Topics in Networks - HotNets '18 - Connecting Battery-free IoT Tags Using LED Bulbs
摘要： We introduce BackVLC, a system to connect battery-free IoT tags using LED bulbs. We make use of bulbs beyond illumination. We send data to the tags with visible light communication (VLC), and retrofit the bulbs with simple circuitry to enable the uplink channel current VLC systems lack, using Radio Frequency (RF) backscatter communication from the tags. Tags process and send data, harvesting energy from light and radio. We present our system design and implementation, evaluate it in preliminary simulation studies and experiments, and discuss the research challenges to develop a complete network architecture. BackVLC is the first work that combines VLC with RF backscatter.
关键词： RF backscatter,LED bulbs,visible light communication,battery-free IoT tags,BackVLC
更新于2025-09-10 09:29:36
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Fabrication of CdS-decorated mesoporous SiC hollow nanofibers for efficient visible-light-driven photocatalytic hydrogen production
摘要： In the present work, we reported the fabrication of CdS decorated mesoporous SiC hollow nanofibers for efficient visible-light-driven photocatalytic hydrogen production. The mesoporous SiC hollow nanofibers were firstly fabricated by electrospinning, followed by hydrothermal treatment to introduce the CdS nanoparticles decorated on the preformed fiber matrix, The resultant CdS/SiC hybrid photocatalysts were systematically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and N2 adsorption. The as-fabricated CdS/SiC hybrids exhibited a robust stability with a release rate up to ~ 124.65?μmol?h?1?g?1 for photocatalytic H2 evolution driven by visible light, which was profoundly enhanced for more than 16 times to that of pristine SiC counterparts, and comparable to the state-of-the-art one of SiC-based photocatalysts.
关键词： CdS,SiC,photocatalytic hydrogen production,visible-light-driven,hollow nanofibers
更新于2025-09-10 09:29:36
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Indoor visible light communications: performance evaluation and optimization
摘要： For indoor visible light communication (VLC), much work has been done when the noise is independent of the input signal. However, less effort is made when the VLC system suffers from the input-dependent noise. Considering the input-dependent noise, this paper focuses on the performance analysis and optimization for indoor VLC system. The Lambertian emission-based channel model and on-off keying modulation are employed. According to the system model, the bit error rate (BER) with a closed-form expression is derived. To enhance the system performance, an optimization problem that minimizes the BER by tilting the receiver plane is formulated. By solving the problem, the optimal tilting angle of the receiver is obtained. Simulation results verify the derived expression of BER. It is also shown that the BER is strongly affected by the input-dependent noise. Moreover, the optimal tilting angles for the receiver at any position are obtained, which can provide some insights for practical system design.
关键词： BER,Tilting receiver plane,Input-dependent noise,Visible light communications
更新于2025-09-10 09:29:36
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One step to prepare CNTs modified porous g-C3N4 with excellent visible-light photocatalytic performance
摘要： A kind of carbon nanotubes (CNTs) modified porous graphitic carbon nitride (CNTs/pg-C3N4) photocatalyst was successfully synthesized via one step thermal polycondensation and completely measured by some instruments, such as XRD, FTIR, TEM, BET, DRS, PL, etc. And the relevant experimental data indicated that loaded CNTs could be beneficial to the photoinduced charges transfer, facilitating photoinduced charge separation rate. Meanwhile, surface area and visible light adsorption of CNTs/pg-C3N4 photocatalyst could be increased and improved. These synergetic effects resulted in the as-synthesized CNTs/pg-C3N4 photocatalyst exhibiting better visible-light-induced photocatalytic performance for organic pollutant degradation and the product of clean energy than bulk g-C3N4, pg-C3N4 and CNTs modified bulk g-C3N4, and excellent stable photocatalytic performance was also observed after several recycling experiments. Finally, a reasonable improved photocatalytic reaction mechanism for CNTs/pg-C3N4 photocatalyst is presented.
关键词： Porous graphitic carbon nitride,Photocatalytic performance,Carbon nanotubes,Photocatalyst,Visible-light
更新于2025-09-10 09:29:36