Key Engineering Materials Vols. 474-476

Abstract: A novel unsymmetrical diarylethene derivative bearing both phenyl and thiophene moieties, in which a chlorine group was substituted at the para-positions of the terminal phenyl ring, was synthesized. At the same time, 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 541 nm in hexane and at 550 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with 297 nm UV light in PMMA. In hexane solution, the open-ring isomer of the diarylethene 1 exhibited relatively strong fluorescence at 462 nm when excited at 316 nm.

Abstract: Two aromatic Schiff base derivatives and the corresponding metal complexes with different substituted groups were synthesized and characterized by many methods. The products were characterized by UV-Vis spectra, FT-IR spectra and thermal analysis, while the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group and oxygen atom in phenolic hydroxyl group participated in coordinating with transition metal ion in different bridged mode. UV spectra also verified that different coordination modes can be performed between metal ions and ligands. In addition, the thermal stability of metal complexes had been obviously superior to that of the ligands. All results give a useful clue to obtain Schiff base derivatives with versatile property by regulating intramolecular substituted group and species of metal ion. The present results have showed potential application in fields of functional material and catalyst.

Abstract: Some novel L-glutamate-based Schiff base compounds with glutamate segment and different substituted groups have been designed and synthesized from the reaction of aromatic L-glutamate amine with different aldehydes. It has been found that depending on the molecular structures and substituted groups, the formed Schiff base compounds showed different properties, indicating distinct regulation of molecular design. UV and IR data confirmed commonly the formation of Schiff base as well as aromatic substituted groups in molecular structures. Thermal analysis also clarified the structural influence of these compounds in different temperature ranges. The difference of thermal stability is mainly attributed to molecular structures, formation of Schiff base group and different substituted groups. These results indicated that the the special properties of Schiff base compounds could be regulated through the design of molecular structures and substituted groups, which leads to potential application in fields of functional material as well as catalyst.

Abstract: This paper introduces the structure and basic principle of planar precision positioning tables. “The same plane” mode and magnetic driver are adopted, on the basis of analytical field, the main design parameters, such as magnet length, coil current and air gap length are defined, and the response simulation is finished. The result shows that this project can meet the request of rigid orientation.

Abstract: The cost of logistics distribution takes account for considerable proportion in logistics costs. Logistic distribution route is of of vital importance to reduce logistics cost. Clarke-Wright Saving Mileage Heuristic Algorithm is an effective method to optimize distribution route.

Abstract: A new unsymmetrical photochromic diarylethene [1-(2-methyl-5-(3-methoxyphenyl)-3-thienyl), 2-(2-methyl-3-benzothienyl)] perfluorocyclopentene (1a), was synthesized, and its photochromic properties such as photochromism, kinetics and electrochemical properties were investigated in detail. The results showed that the compound exhibited excellent photochromism both in solution and in PMMA film with alternating irradiation by UV/Vis light. The kinetic and electrochemical experiments indicated that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction, and the electrochemcial switching property can be potential use for electrochemistry data storage. At last, using this dithienylethene as recording medium was performed successfully.

Abstract: A new unsymmetrical photochromic diarylethene compound, [1-(2-methyl-5-(3-fluorophenyl)-3-thienyl), 2-(2-methyl-3-benzothienyl)]perfluorocyclopentene (1o), was synthesized and its photochemical properties, such as photochromism and fluorescence in solution as well as in PMMA amorphous film were investigated in detail. The results showed that the compound exhibited remarkable photochromism, changing from colorless to violet after irradiation with 297 nm UV light both in solution and in PMMA film. Finally, using this dithienylethene as recording medium, polarization optical recording was carried out successfully.

Abstract: Green design is now a major trend in product design. The paper first discusses the importance of green design, then it tells the vital role that materials play in product design. Finally, it generalizes the concept of Green Material according to the requirements of green design. At the same time, the paper puts forward the principles that the material selection should live up to in green design so as to meet variety functional and environmental demands.

Abstract: A new unsymmetrical photochromic diarylethene 1-(2-methyl-benzothiophenyl)- 2-(2-methyl-5-(4-chlorophenyl))perfluoroncyclopentene (1a), was synthesized and its optoelectronic properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films and fluorescences were investigated. The photochromic reaction kinetics indicated that the cyclization process of 1a belongs to the zeroth order reaction and the cycloreversion process belongs to the first order reaction. Using diarylethene 1/PMMA film as recording medium and a linearly polarized 633 nm laser diode for recording and readout, polarization multiplexed image recording can be carried out in this film, which illustrated that the diarylethene can be potentially used as holographic optical recording medium.

Abstract: A new photochromic diarylethene of bis(3-methyl-2-thienyl)ethene and bis(2-methyl-3- benzofuran)ethene was synthesized. Its photochromic, fluorescent and optical strorage properties were investigated. The compounds exhibited remarkable photochromism both in solution and in PMMA film. In hexane, the open-ring isomer of the diarylethene 1 exhibited relatively strong and clear fluorescent switches when excited at 270 nm. The fluorescence intensity declined along with the photochromism upon irradiation with 297 nm light. The results showed that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction. This new photochromic system also exhibited remarkable optical storage character.