Advanced Materials Research Vols. 482-484

Abstract: Surface modifications of natural rubber latex films were carried out to improve the hydrophilicity by UV-induced immobilization of water-soluble butyryl derivative of chitosan using the photosensitive hetero-bifunctional crosslinking reagent, 4-azidobenzoic acid. The effects of the concentration of modified chitosan solution and UV irradiation time on the water contact angle values of natural rubber latex films were studied. ATR-FTIR analyses confirmed that the O-butylrylchitosan molecules were covalently bonded onto the surface of natural rubber latex film. The water contact angle value of natural rubber latex film which is about 95o reduces to 55o significantly with the introduction of O-butylrylchitosan. The results indicate that the hydrophilic behaviour of natural rubber latex film has been improved by immobilization of O-butylrylchitosan.

Abstract: Abstract: We report the dependence of the all optical switching effect of 3-hydroxyflavone (3-HF) on the efficiency of excited state proton transfer (ESPT) using pump probe method. A cw probe laser beam of 632.8nm passing through the sample is switched off by a 35ps pulse pump laser beam of 355nm. We also measured the nonlinear refractive index of 3-HF in different solvents by using z-scan technique. The results show that the optical switching effect will be more obvious when the efficiency of excited state proton transfer is improved, while not proportional to the nonlinear refractive index of 3-HF.

Abstract: The pyrene/pyrrole copolymer (Pn/Py copolymer) has been sucessfully synthesized by the facile chemically oxidative copolymerization. UV-vis and FT-IR spectra are used to investigate the molecular structure of the copolymer. The results show that pyrene and pyrrole units in the copolymer chain are interconnected via α, α-coupling to form a linear structure. At the same concentration, the copolymer solution exhibits the strongest green fluorescence with a maximum emission at 503 nm and a large stokes shift of about 113 nm by fluorescence spectrometer. The excellent fluorescence of Pn/Py copolymer may be due to its better planar molecular structure and higher large π-conjugation, that is confirmed by UV-vis spectra and molecular simulation.

Abstract: A pyridinium dye with N-butyl-carbazole as an electron donor group and pyridinium cation as electron acceptor group has been synthesized. The crystal structure and photophysical properties of the dye in different solvents are researched. The interaction between the dye and DNA is also researched. The results reveal that the dye can be used as a DNA probe.

Abstract: The reported mathematical models of magnetorheological (MR) damper cannot make a good tradeoff among reflecting the damper’s nonlinear behavior and controllability. Damping characteristic experiments have been conducted on a MR damper. A composite polynomial model has been proposed integrating the experimental investigation and the polynomial model, in which the plot of polynomial coefficient vs. current is divided into two sections to reflect the property of the current saturation, meanwhile, the affections of exciting amplitude and frequency are considered in this model. The reverse model of the proposed model is easy to be obtained, so it is convenient to realize an open-loop control system to achieve a desirable damping force. The parameters of this model are identified using experimental data in a certain frequency and amplitude, as well as diverse currents. Compared numerical simulation with experimental data, it is verified that the proposed model can accurately predict the damping force without modifying the parameters of the model when frequency, amplitude and current changed.

Abstract: Combinatorial material synthesis and high throughput evaluation technique have been developed to accelerate material discovering and optimizing. The thin-film combinatorial material library (or material chip), similar to the integrated circuit chip, contains thousands even millions of different compounds, and could be used to screen for the desirable physical or chemical properties. In our work, the rare earth activated gadolinium aluminate perovskite phosphor(GAP:RE_1x, RE_2y, RE ion vary among Eu³⁺, Ce^3+,4+, Pr^3+,4+) combinatorial library is made by ion beam sputtering sequence deposition and two-step thermal processing. The GAP:RE_1x, RE_2y, combinatorial library indentify the “lead” red luminescent compound as GAP:Eu_0.11 from the 16 candidates with the help of the photoluminescent (PL) photograph under UV light. Three another compounds have been also picked out as GAP:Eu_0.1, GAP:Eu_0.1,Ce_0.01, GAP:Eu_0.1,Pr_0.01. Other than the information on “lead” compounds, the discrete combinatorial library provides a quick way to map out the relationships between activators and host, sensitizers and activators： 1) Eu³⁺ is a better red luminescent activator than Ce^3+,4+, Pr^3+,4+in GAP polycrystalline; 2)Neither Ce^3+,4+ nor Pr^3+,4+ is a proper sensitizer for Eu³⁺. The excitation and emission spectral indicate the resonance energy transfer between the activator and sensitizer must have happened, which leads to Ce^3+,4+ or Pr^3+,4+ codoping decrease Eu³⁺ red luminescence intensity. The candidates in powder form are prepared by nitric-citric method for more detailed characterization. All the screening results, obtained from the combinational library, are coherent with the powder phosphor experiments.

Abstract: Chemical structure and liquid crystal behavior of mesogenic monomer(Trans, trans)-4-propyl-4’-vinyl- bicyclohexane(3HHV) with platelet texture of a blue phase and mesogenic monomer(Trans, trans)-4-propyl-4’-propenyl –bicyclohexane(4HHV) with cholesteric phase were studied. The chemical structure of mesogenic monomers were determined by Fourier transform infrared spectroscopy, and Hydrogen-nuclear magnetic resonance spectra. Liquid crystal behavior of mesogenic monomers were analyzed by polarizing optical microscopy and X-ray diffraction. Thermal properties of mesogenic monomers were researched by differential scanning calorimetry. The results were that: 3HHV showed the platelet texture of a blue phase was considerably different from single color texture of blue phase we always refer to, and assuredly belong to a new kind of blue phase liquid crystal. These two kinds of cyclohexane liquid crystal monomer also showed good thermal stability.

Abstract: To clarify the efficiency of internal reduction during continuous casting bloom when the technology of soft reduction is applied, a thermal-mechanical coupled FEM model was developed to investigate the internal reduction efficiency. Basing on the model developed in this article, the area variation of the mushy zone under soft reduction could be calculated. A new calculation method of internal reduction efficiency through the area variation of mushy zone was proposed. The variation trend of internal reduction efficiency as a function of soft reduction amount, calculated by two different methods, was introduced.

Abstract: Abstract: With the purpose to improve the mechanical properties and cut costs of chitosan films, a series of gelatin-chitosan films were prepared. The effect of gelatin content on the mechanical properites of films was studied. FT-IR spectrum and X-ray diffraction analysis showed good compatibility between gelatin and chitosan. The composite films exhibited a higher TS(tensile strengths) and ES(elongation at break) compared with chitosan film, especially when the content of gelatin in blends was 30%. The TS and ES revealed that the interaction between chitosan and gelatin was the strongest when the content of gelatin in blends was 30%. The results obtained from percent water absorption indicated these two biopolymers were high hydrophilicity polymer. The water solubility of composite films was higher than chitosan films. The results suggest that the interactions between gelatin and chitosan was good for the mechanical properties of composite films.

Abstract: The micro-structure of sand body is relative to waterflooding rule and remaining oil distribution closely. Based on the division of single sand body, the type and the feature of the micro-structure of sand body of X formation in X area are researched. Five types of micro-structure are concluded：structural height，fault height, neighbouring fault, the area controlled by parallel fault, clinoform.And the affection of different type of micro-structure on remaining oil distribution is studied, which can indicate tapping the latent and the development of remaining oil.