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We studied the high-order harmonic generation (HHG) from 2D solid materials in circularly and bichromatic circularly polarized laser fields numerically by simulating the dynamics of single-active-electron processes in 2D periodic potentials. Contrary to the absence of HHG in the atomic case, circular HHGs below the bandgap with different helicities are produced from intraband transitions in solids with C4 symmetry driven by circularly polarized lasers. Harmonics above the bandgap are elliptically polarized due to the interband transitions. High-order elliptically polarized harmonics can be generated efficiently by both co-rotating and counter-rotating bicircular mid-infrared lasers. The cutoff energy, ellipticity, phase, and intensity of the harmonics can be tuned by the control of the relative phase difference between the 1ω and 2ω fields in bicircularly polarized lasers, which can be utilized as an ultrafast optical tool to image the structure of solids. [ABSTRACT FROM AUTHOR]

A series of glass fibre doped Ce–W/TiO2 catalysts were investigated for the selective catalytic reduction of NOx by NH3. The adhesion and mechanical strength of the CeO2–WO3/TiO2 catalyst was greatly enhanced by the addition of 6% glass fibre. However, the glass fiber contains a small amount of alkali metals, which occupied the active site on the surface of the CeO2–WO3/TiO2 catalysts, thus the catalytic performance of catalyst was inhibited by the addition of glass fibre. Furthermore, BET, XRD, XPS, TPR and TPD methods revealed that the addition of glass fiber can inhibit the formation of catalyst pore structure and reduce the content of Ce3+, adsorbed oxygen and the Brönsted and Lewis acid sites on the catalyst surface, thereby affecting the redox abilities, nitrogen oxides and ammonia adsorption capacity of catalysts. [ABSTRACT FROM AUTHOR]

Since ultraviolet (UV) light, as well as blue light, which is part of visible light, is harmful to skin, samarium—cerium compounds containing Sm2O2S were synthesized by co-precipitation method. This kind of compounds blocks not only UV light, but also blue light. The minimum values of average transmittance (360–450 nm) and band gap of samarium—cerium compounds were 8.90% and 2.76 eV, respectively, which were less than 13.96% and 3.01 eV of CeO2. Elemental analysis (EA), X-ray diffraction (XRD), Fourier transformation infrared (FTIR), and Raman spectra determined that the samples contained Ce4O7, Sm2O2S, Sm2O3, and Sm2O2SO4. The microstructure of samples was analyzed by scanning and transmission electron microscopies (SEM and TEM). X-ray photoelectron spectrum (XPS) showed that cerium had Ce3+ and Ce4+ valence states, and oxygen was divided into lattice oxygen and oxygen vacancy, which was the direct cause of the decrease of average transmittance and band gap. [ABSTRACT FROM AUTHOR]

A series of glass fibre doped Ce–W/TiO2 catalysts were investigated for the selective catalytic reduction of NOx by NH3. The adhesion and mechanical strength of the CeO2–WO3/TiO2 catalyst was greatly enhanced by the addition of 6% glass fibre. However, the glass fiber contains a small amount of alkali metals, which occupied the active site on the surface of the CeO2–WO3/TiO2 catalysts, thus the catalytic performance of catalyst was inhibited by the addition of glass fibre. Furthermore, BET, XRD, XPS, TPR and TPD methods revealed that the addition of glass fiber can inhibit the formation of catalyst pore structure and reduce the content of Ce3+, adsorbed oxygen and the Brönsted and Lewis acid sites on the catalyst surface, thereby affecting the redox abilities, nitrogen oxides and ammonia adsorption capacity of catalysts. [ABSTRACT FROM AUTHOR]

In this paper, a Ce-W/TiO2-mSiO2 catalyst was prepared by a co-precipitation method with the addition of silicon acid to enhance and broaden the denitrification (deNOx) efficiency and temperature range of the Ce-W/TiO2 catalyst. The test results of deNOx performance showed that temperature ranges of the 80% and 90% deNOx efficiencies of the Ce-W/TiO2 catalyst with 30% silicic acid were increased by 35 °C and 30 °C, respectively, and the highest deNOx efficiency was increased to 99.53% compared with that without silicic acid. Moreover, the XRD, BET, SEM, XPS, NH3-TPD and H2-TPR analysis revealed that strong water absorption of silicic acid provided more SiO2 for the catalyst to increase its specific surface area. Meanwhile, the volume of a TiO2 cell increased and the crystallinity of CeO2 decreased, which enhanced the number of Lewis and Brønsted acid sites on the catalyst surface and promoted the deNOx reaction. Besides, the ratios of Ce3+ and Oα on the catalyst surface were about doubled with the addition of 30% silicic acid, thus improving the deNOx performance of the catalyst. [ABSTRACT FROM AUTHOR]

Research has been conducted on the Treponema denticola chymortypsin-like protease. The identification of the gene encoding protease-associated protein and the description of the posttranslational processing event mediated by the PrtP protein are discussed.