Advanced Materials Research Vols. 455-456

Abstract: Investigate a melting and solidification of heat storage and release which used in building retaining structure, material of storage energy and phase change. In the process of phase change, liquid phase is used as two ways of heat exchange: pure heat conduction and natural convection, and we exploit CFD software to carry out numerical simulation. To compare and analyze under melt and solidification, the proportion of solid and liquid, the time of phase change, the interface of phase change and motion temperature image of liquid-region. To probe into the effect of natural convection under the heat transfer from phase change and the impact of regulation of by heating and cooling conditions, and it verified by experiments.

Abstract: A mechanically robust infrared high-index coating material is essential to the infrared interference coatings. Lead germanium telluride (Pb_1-xGe_xTe) is a pseudo-binary alloy of IV-VI narrow gap semiconductors of PbTe and GeTe. In our investigation, the hardness and Young’s modulus of thin films of Pb_1-xGe_xTe, which were deposited on silicon substrates using electron beam evaporation, were identified by means of nanoindentation measurement. It is demonstrated that layers of Pb_1-xGe_xTe have greater hardness and Young’s modulus compared with those of PbTe. These mechanical behaviors of layers can be linked to a ferroelectric phase transition from a cubic paraelectric phase to a rhombohedral, ferroelectric phase. Moreover, the strength loss in the layers of Pb_1-xGe_xTe can be also explained in light of strong localized elastic-strain fields in concentrated solid solutions.

Abstract: An unsymmetrical diarylethene derivative was synthesized, and its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 548 nm in hexane and at 558 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The PMMA film of the diarylethene 1a exhibited relatively strong fluorescence at 413 nm when excited at 311 nm. The fluorscence intensity is highest at the concentration of 1.0×10^-4 mol/L when excited at 311 nm.

Abstract: A new unsymmetrical isomeric diarylethene was synthesized, namely 1-(2,4-dimethyl-5-thiazolyl)-2-[2-methyl-5- (3-methoxyphenyl)-3-thienyl] perfluorocyclopentene (1o). Its photochromic reactivity both in solution and in PMMA film, photoconversion ratio at photostationary state, and fluorescence were investigated in detail. The compound displayed excellent photochromism both in solution and in PMMA film. The isomeric compound also functioned as a fluorescence switch and concentration dependence on the fluorescence spectrum in hexane.

Abstract: A novel photochromic diarylethene based on isoxazole moiety was synthesized and its photochromic and fluorescent properties were also investigated. The compound exhibited remarkable photochromism, changing from colorless to purple after irradiation with UV light both in solution and in PMMA film. In hexane solution and in PMMA film, the open-ring isomer of the diarylethene 1 exhibited relatively remarkable fluorescence. The results indicated that the isoxazole moiety played a very important role during the process of photochromic reaction for the diarylethene derivative. Using this dithienylethene 1c as optical storage was performed successfully.

Abstract: A new unsymmetrical photochromic diarylethene 1-(2,4-dimethyl-3-isoxazol)-2-[2-methyl-5-(2-chlorophenyl) -3-thienyl] perfluorocyclopentene (1a) has been synthesized. Its photochromic properties in solution and PMMA film were investigated. Diarylethene 1a changed the color from colorless to red upon irradiation with 297 nm UV light, in which absorption maxima were observed at 515 nm in hexane and at 526 nm in PMMA film, The results demonstrated that it can be potentially used as polarization holographic optical recording medium.

Abstract: A new unsymmetrical photochromic diarylethene 1-(2-methyl-3-benzofuranyl )-2- (2-n-butyl-5-hydroxymethyl-3-thienyl ) perfluoroncyclopentene (1o) , was synthesized and its optoelectronic properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films, fluorescences were investigated. This new photochromic system also exhibited remarkable optical storage character.

Abstract: A new class of diarylethenes based on a hybrid structure of thiophene and naphthalene has been developed and its properties including photochromism, kinetics and fluorescence were investigated in detail. The results showed that the compound exhibited obvious photochromism, changing from colorless to red after irradiation with 297 nm UV light both in solution and in PMMA film. The kinetic experiments indicated that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction in hexane solution. At last, the results demonstrated that the diarylethene compound had attractive properties for potential application in optical storage.

Abstract: A new photochromic diarylethene 1a has been synthesized, and its photochromic, fluorescent and optical recording strorage properties were investigated. The compound exhibited remarkable photochromism and clear fluorescent switches both in solution and in PMMA film. This new photochromic system also exhibited remarkable optical recording storage character.