Applied Mechanics and Materials Vol. 662

Abstract: A new unsymmetrical photochromic diarylethene 1-(2-methyl-5-phenyl-3-thiophene)-2-[2-methyl-5-phenyl-(4-vinyl)-3-thiophene] 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 blue upon irradiation with 297 nm UV light, in which absorption maxima were observed at 596 nm in acetonitrile.

Abstract: A novel photochromic diarylethene bearing a pyrimidine moiety, 1-(2,4-dimethoxyl-5-pyrimidinyl)-2-[2-methyl-5-(3-cyano)-3-thieny-l] perfluorocyclopentene has been synthesized. Its properties, including photochromic behavior and fluorescent properties, have been investigated. The compound exhibited remarkable photochromism, changing from colorless to blue after irradiation with UV light. The results indicated that the pyrimidine moiety played a very important role during the process of photoisomerization reactions.

Abstract: An asymmetrical photochromic diarylethene1-(2-Methyl-3-benzothiophene)-2-[2-methyl-5-(3-cyanophenyl)-3-thienyl] perfluorocyclopentene (1o) was synthesized and its phtochromic, fluorescent properties in both solution and PMMA films were investigated in detail. This compound exhibited remarkable photochromism, upon irradiation with 297 nm UV light, the colorless solution of 1o turned to violet with a new visible absorption band centered at 535 nm (ε = 1.08 × 10⁴ L mol^-1 cm^-1) attributable to the closed-ring isomer 1c. The emission intensity of diarylethene 1o in a photostationary state was quenched to ca. 32% in hexane and 43% in PMMA film.

Abstract: An asymmetrical photochromic diarylethene 1-[2-methyl-5-(3-trifluoromethyl)-3-thienyl]-2-[2-methyl-5-(9-phenanthren-e)-3-thienyl] perfluorocyclopente-ne was synthesized and its photochemical properties were investigated in detail. The results demonstrated that the compound has excellent photochromic properties and good fluoresence. The cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction.

Abstract: A new symmetrical photochromic diarylethene 1,2-bis [2-methyl-5-(9,9-dihexyl-fluorene)-3-thienyl] perfluorocyclopentene (1o) has been synthesized, and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene 1o in acetonitrile solution was investigated. The maxima absorption of compound closed-ring isomer 1c is 619 nm. The open-ring isomer of the diarylethene 1o exhibited fluorescence at 390 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light,The results showed that this compound exhibited reversible photochromism and fluorescent switching in solution after irradiation with UV light and visible light.

Abstract: A photochromic diarylethene of 1-(2-methyl-1-benzofuran-3-yl)-2-(2-methyl-5-(4-benzylazide)-3-thienyl)) perfluorocyclopentene was synthesized and its properties such as photochromism and fluorescence in solution were investigated in detail. The diarylethene has shown good photochromic behavior in solution with alternating irradiation by UV/vis light. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Abstract: An unsymmetrical photochromic diarylethene which called 1-[2-methyl-5-(3-cyanophenyl)-3-thienyl]-2-[2-methyl-5-(4-pentylphenyl)-3-thienyl] perfluorocyclopentene (1a) was synthesized and its properties such as photochromism and fluorescence were investigated in detail. The results showed that this compound undergo reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in both solution and a PMMA film.

Abstract: Monte Carlo computer simulations based on the binary collision approximation, TRIDYN program, have been applied to calculate the concentration depth profiles of implanted multi-charged molybdenum ions in H13 steel. The sputtering effect of a high dose ion implantation and influence of multi-charged ions on the concentration depth profile of implanted molybdenum ions can both be considered in the TRIDYN simulation. For the Monte Carlo computer simulation, the chosen pseudo-projectiles are 500000. The chosen extraction voltages are 48kV and 25kV, respectively, and an implantation doses of 5×10¹⁷cm^-2 to compare the results which have been published related to molybdenum ion implantation. TRIDYN program is better than SRIM program in the calculation of the concentration depth profiles of implanted multi-charged ions. And the calculation result of the TRIDYN program is different from the experiment result. The other factors of affecting the concentration depth profile have also been discussed finally.

Abstract: The islets in river are the most important recreation areas in city. The special geological conditions and geographical location determine the frangibility of the eco-environment. The inappropriate or excessive recreation development will cause the degradation even deterioration of the eco-environment system of urban islet in river. According to the characteristics of the eco-environmental frangibility of urban islet in river, the paper constructs a model of “formation-influence-regulation" and applies it to the Dongzhou Islet in Xiangjiang River.

Abstract: In this paper, steel slag as the main raw material, modified steel slag adsorbent was prepared using steel slag and the active carbon as the starting materials. The influences of doping substance, the particle size, calcining temperature and doping ratio on the decoloration rate of methyl orange wastewater were investigated. The results showed that the decoloration rate of methyl orange can reach 93.62% when the doping substance was the activated carbon, the particle size was 120 mesh, the calcining temperature was 700°C, the doping ratio was 1:1.