The effects of Brønsted acid strength and pore confinement on the Beckmann rearrangement reaction over solid acid catalysts have been explored.

Visible light communication (VLC) has recently emerged to become a promising wireless communication technology. Vehicle lights and traffic lights have started to utilize LEDs and due to their shorter response time, they can be easily modified to become VLC transmitters. In addition, cameras embedded in smartphones can be used as VLC receivers. As a result, Vehicular VLC (V2LC) between vehicle lighting and smartphone cameras has the potential to enable a great number of applications with low cost. In this paper, a prototype V2LC system that utilizes undersampled frequency shift ON-OFF keying (UFSOOK) modulation is proposed. The system utilizes rolling shutter cameras as the receiver and takes advantages of its characteristics to improve the receiving performance. An offthe-shelf vehicle LED taillight is used as the transmitter. Information is transmitted in the continuous state (ON-OFF) changes of LEDs which are invisible to human eyes. The performance evaluation results demonstrate that the communication prototype is robust and can resist common optical interferences and noises within the image.Keywords-Visible light communications; rolling shutter; smartphone camera; vehicular visible light communications (V2LC); undersampled frequency shift ON-OFF keying (UFSOOK)

Mesoporous MCM-22 zeolite (meso-MCM-22) has been prepared by treating MCM-22 with sodium hydroxide solution through an organic amine-assisted reversible structural change. The alkaline treatment conditions, such as temperature, time, organic amine type, and its amount, were examined in detail. The desilication with sole NaOH caused an easy collapse of the crystalline structure of MWW topology. In contrast, the NaOH treatment with the coexistence of piperidine introduced mesopores of ∼20 nm into the MCM-22 crystals. Meanwhile, the calcined MCM-22 with three-dimensional (3D) MWW crystalline structure was converted to a 2D layered precursor with a well retained framework. The acid sites related to framework aluminum cations were almost intact after mesopore creation, as evidenced by pyridine or ammonia adsorption–desorption and 27Al NMR investigation. In comparison with MCM-22, meso-MCM-22 possessed a larger external surface, which mitigated effectively the steric restrictions to bulky molecules imposed by the intracrystal micropores. Meso-MCM-22 was superior to MCM-22 in the cracking of 1,3,5-triisopropyl benzene as well as the alkylation of benzene with isopropyl alcohol.

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Sn-Beta zeolites, with high Sn content and smaller crystal size, hydrothermally synthesized in F−-free medium using N-cyclohexyl-N,N-dimethylcyclohexanaminium hydroxide as the structure-directing agent with the assistance of Na+ and seed, are highly active as Lewis acid catalysts.

With the aggravation of the energy crisis and environmental problems, biomass resource, as a renewable carbon resource, has received great attention. Catalytic fast pyrolysis (CFP) is a promising technology, which can convert solid biomass into high value liquid fuel, bio-char and syngas. Catalyst plays a vital role in the rapid pyrolysis, which can increase the yield and selectivity of aromatics and other products in bio-oil. In this paper, the traditional zeolite catalysts and metal modified zeolite catalysts used in CFP are summarized. The influence of the catalysts on the yield and selectivity of the product obtained from pyrolysis was discussed. The deactivation and regeneration of the catalyst were discussed. Catalytic co-pyrolysis (CCP) and microwave-assisted pyrolysis (MAP) are new technologies developed in traditional pyrolysis technology. CCP improves the problem of hydrogen deficiency in the biomass pyrolysis process and raises the yield and character of pyrolysis products, through the co-feeding of biomass and hydrogen-rich substances. The pyrolysis reactions of biomass and polymers (plastics and waste tires) in CCP were reviewed to obtain the influence of co-pyrolysis on composition and selectivity of pyrolysis products. The catalytic mechanism of the catalyst in CCP and the reaction path of the product are described, which is very important to improve the understanding of co-pyrolysis technology. In addition, the effects of biomass pretreatment, microwave adsorbent, catalyst and other reaction conditions on the pyrolysis products of MAP were reviewed, and the application of MAP in the preparation of high value-added biofuels, activated carbon and syngas was introduced.

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In this study, ZrO2 and Zn–ZrO2 nanoparticles (NPs) with a series of Zn ion doping amounts were synthesized by the sol-gel process and utilized as substrates for surface-enhanced Raman scattering (SERS). After absorbing the probing molecule 4–mercaptobenzoic acid, the SERS signal intensities of Zn–ZrO2 NPs were all greater than that of the pure ZrO2. The 1% Zn doping concentration ZrO2 NPs exhibited the highest SERS enhancement, with an enhancement factor (EF) value of up to 104. X-ray diffraction, X-ray photoelectron spectroscopy, Ultraviolet (UV) photoelectron spectrometer, UV–vis spectroscopy, Transmission Electron Microscope (TEM), and Raman spectroscopy were used to characterize the properties of Zn–ZrO2 NPs and explore the mechanisms behind the SERS phenomenon. The charge transfer (CT) process is considered to be responsible for the SERS performance of 4–MBA adsorbed on Zn–ZrO2. The results of this study demonstrate that an appropriate doping ratio of Zn ions can promote the charge transfer process between ZrO2 NPs and probe molecules and significantly improve the SERS properties of ZrO2 substrates.