Advanced Materials Research Vol. 952

Abstract: Anodic coatings were prepared by micro-arc on AZ91 magnesium alloys in solutions with different calcium salts. The influence of calcium salts on the coating properties were studied. The result shows that anodic coatings formed in Ca (OH)₂ system has higher calcium content. When the Ca (OH)₂ concentrations is 2g/L, the Ca content is the highest, and the Calcium addition achieve the best corrosion resistance.

Abstract: With the study of frost resistance of plain concrete and mixed concrete with fly-ash substituted and mixed concrete with fly-ash substituted and nanoSiO₂ as admixture, the outcomes of the test go that the frost resistance of concrete with nanoSiO₂ will be increased considerably.

Abstract: The effects of tungsten doping in La2Mo1.5W0.5O9 sample were studied using dielectric relaxation measurements. The results indicate that W6+ can suppress the α/β phase transition in the La2Mo2O9. Additional to the low-temperature relaxation peak Pd associated with oxygen ion diffusion, a new dielectric loss peak Ph associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion distribution was observed around 740 K.

Abstract: The N/C co-doped TiO₂ thin films were successfully deposited on medical glass slide by pulsed negative bias arc ion plating. The influence of pulsed negative bias, annealing temperature on films properties was investigated. Film structure, surface morphologies and optical properties were measured with XRD, SEM and UV-VIS transmittance spectroscope. The results show that the most absorption edges of the as-deposited films increase with the rising of the pulse negative bias, and the maximum of 540 nm is achieved under-600V bias. The films absorption edges increase in different degree after annealing at 400°Cfor 2h and 4h, and the best extension can increase 46nm after annealing. The interaction of the annealing treatment and bias functions enhance the N and C reaction activities and extend absorption edge. The greatest absorption edge dater of the co-doped TiO₂ films under the negative pulse bias for 0V can reach 550nm after the annealing at 400°Cfor 2h. The crystal morphology become inconspicuously with the bias increasing from 0V to-300V, which is corresponding to the XRD result, the anatase diffraction peaks weaken obviously.

Abstract: A novel unsymmetrical isomeric photochromic diarylethene based on phenanthrene unit, {1-[2-methyl-5-(10-phenanthrenyl)-3-thienyl]-2-{2-methyl-5-[4-(2-(1,3-dioxolane)) phenyl]-3-thienyl}} perfluorocyclopentene (1o), was designed and synthesized. Its properties were investigated in detail, including photochromic, kinetics and fluorescent. The results showed that the compound exhibited excellent photochromism, changing from colorless to violet after irradiation with UV light in solution. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. Furthermore, the fluorescence intensity of the photochromic diarylethene 1o declined dramatically.

Abstract: A new unsymmetrical photochromic diarylethene [1-(1,2-dimethyl-cyano-3-pyrrole)-2-(2-methyl-5-thienyl-3-thienyl] perfluorocyclopentene (1o) has been synthesized, and its photochromic reactivity, fluorescent were also investigated. The results showed this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in solution,Diarylethene 1 changed the color from colorless to purple upon irradiation with 297 nm UV light, in which absorption maxima were observed at 585 nm in hexane.

Abstract: A new asymmetry photochromic diarylethene based on a phenanthrene, which is named 1-{2-methyl-[5-(4-methylene-hydroxyl) phenyl]-3-thienyl}-2-[2-methyl-5-(10-phenanthrenyl)-3-thi-enyl] perfluorocyclopentene 1o, was designed and constructed successfully. And its properties have been discussed systematically, including photochromic, HPLC, concentration effect and fluorescent switch. The result indicated that its photochromic behaviors could be modulated by UV/Vis light, changing between colorless and violet in dichloromethane solution, respectively. What’s more, it could also response to various concentrations, with emission maximum density 5 × 10^-5 mol L^-1. In addition, the optical switch experiment illustrated that the diarylethene 1 functioned as a remarkable fluorescent switch, which fluorescent modulation efficiency was 63% in the photostationary state.

Abstract: An asymmetrical photochromic diarylethene 1-(2,4-dimethyl-5-thiazolyl)-2-(2-methyl-5-(2-methyl)-3-thienyl) perfluorocyclopentene (1o) was synthesized and its photochromic properties were investigated. Upon irradiation with 297 nm UV light, 1o exhibited photochromism in solution and in PMMA film. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively. Moreover, diarylethene 1o also exhibited obviously fluorescence switches along with the photochromism.

Abstract: A novel photochromic diarylethene based on a six-membered pyrimidine moiety 1-(2,4-dimethoxyl-5-pyrimidinyl)-2-[2-methyl-5-(4-n-pentylbenzene)-3-thienyl] perfluorocyclopent-ene has been synthesized. Its properties, including photochromic behavior and fluorescent properties, have been investigated. The compounds exhibited remarkable photochromism, changing from colorless to red after irradiation with UV light both in solution and in PMMA film. The fluorescence had a remarkable initial increase with subsequent dramatic decrease with increasing concentration. The results indicated that the pyrimidine moiety played a very important role during the process of photoisomerization reactions.

Abstract: A new unsymmetrical photochromic diarylethene compound, 1-(2-Methyl-3-benzothiophene)-2-(5-(4-ethynyl)-2-methylthiophen-3-yl)Perfluorocyclopentene (1o),was synthesized and its photochemical, fluorescence properties were investigated systematically both in solution and PMMA amorphous film. The results showed that this compound exhibited reversible photochromism, changing from colorless to pink after irradiation with 297 nm UV light both in solution and in PMMA amorphous film. The photochromic reaction kinetics indicated that the cyclization processes of 1 belong to the zeroth order reaction and the cycloreversion process belong to the first order reaction.