Advanced Materials Research Vol. 669

Abstract: We examine two-photon selective reflection (SR) spectroscopy in a system of -type three-level atoms at the interface with a ferroelectric layer on a dielectric surface. Two-photon SR lines, exhibiting Dicke-narrowing profiles due to atom-wall collision and Doppler free configuration, are periodically modulated by the thickness of the atomic vapor. These SR lines can be modified by the thickness and the complex refractive index of the ferroelectric layer, and can probably be a feasible method used in the measurement of the optical parameters of the ferroelectric layer.

Abstract: Nano Fe2O3 were added into polypropylene (PP) / ammonium polyphosphate (APP) / melamine phosphate (MPOP) / 1-oxo-4-hydroxymethyl-2,6,7-trioxal-phosphabicyclo-[2.2.2]octane (PEPA) to prepare intumescent flame-retarded nanocomposites. The flame retardance and thermal stabilization and intumescent char layer have been investigated by UL-94 test, TGA and SEM. Result showed that the behavior of this intumescent system can be enhanced significantly by the addition of small amounts of nano Fe2O3. TGA results present higher thermal stability of the PP-IFR-Fe2O3 in high temperature when compared with the PP-IFR. SEM indicated the char layer from the PP-IFR-Fe2O3 system has a compact and tough char structure compared with the PP-IFR. Adding 0.3 wt% and 27 wt% IFR into PP, the PP-IFR-Fe2O3 system provided good fire retardant behavior, mechanical properties and achieved UL94 V-0 rating.

Abstract: Well-defined amphiphilic graft polymer brushes containing fluoropolymer segments have been successfully prepared by (i) UV-induced coupling of 4-vinylbenzyl chloride (VBC) with the hydrogen-termined Si(100) (Si-VBC surface), (ii) surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxyethl methacrylate (HEMA) to produce the Si–VBC–g–P(HEMA) surface as the backbone of macroinitiator for further ATRPs, (iii) coupling of 2-bromoisobutyrl bromide with the HEMA polymer(P(HEMA)) by the esterification to produce the macroinitiators for the subsequent ATRP(Si–VBC–g–P(HEMA)-R3Br), (iv) surface-initiated ATRP of 2,2,3,3,4,4,4-heptafluorobutyl acrylate (HFBA) to produce the Si–VBC–g–P(HEMA)–g–P(HFBA) surface, and (v) the active P(HFBA) chain ends being used as the initiator for the subsequent ATRP of poly(ethylene glycol) monomethacrylate (PEGMA) to produce the amphiphilic Si–VBC–g–P(HEMA)–g–P(HFBA)–b–P(PEGMA) brush surface. The chemical composition and functionality of the silicon surface were characterised by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometry.

Abstract: We have proposed a biosensor using a one-dimensional (1D) photonic crystal with surface plasmon resonance (SPR) effect. The wavelength interrogation method has been used to study the performance of the sensor. Numerical simulations based on rigorous coupled wave analysis (RCWA) method show that the sensitivity of the optimized sensor is 137 nm/RIU (per refractive index unit).

Abstract: MgO/ZrO2-La2O3-y solid base catalyst was prepared by precipitation immersion process. Raman spectroscope and X-ray powder diffraction (XRD) were used to determinate the surface phase and bulk phase of solid base catalyst. Temperature programmed desorption of CO2 (CO2-TPD) was employed to study the surface basicity of the catalyst. The results reveal that Mg2+ ion plays a key role in the stabilization of tetragonal phase ZrO2 not only in the bulk but also on the surface of catalyst when the Mg/Zr molar ratio is 0.4. The doping of La2O3 has the role of improving the dispersion of the active component MgO on ZrO2 surface, consequently resulting in the improvement of the catalytic activity of the catalyst rather than stabilizing tetragonal phase ZrO2.

Abstract: Silver ions (Ag⁺) used as secondary ion, cetyl trimethyl ammonium bromide (CTAB) used as surfactant and ascorbic acid(AA) used as reducing agent, the gold(Au) nanorods were synthesized by seed-mediated growth method. The resulting substrates have been characterized by UV-vis spectroscopy. The law of Au nanorods growing was researched by controlling concentration of CTAB, Ag⁺, seed-fluid and AA. The results showed that the optimum reaction conditions are 0.10 M CTAB, 0.1×10^-3 M Ag⁺, 0.0056×10^-3 M AA, 0.48×10^-6 M seed-fluid and system temperature 30°C.

Abstract: The slip model of micro channel in reservoir adsorbed by hydrophobic nanoparticles(HNPs) was established. The drag reduction characteristics were verified by the core slice adsorption experiment and core displacement experiment respectively. Results show that a compact HNPs adsorption layer can be built on the surfaces of the micro channel and the wettability of the surfaces can be changed from hydrophilic into strong hydrophobic. The slip lengths were calculated according to the slip model, the results show that the core surfaces can produce a slippage ranging from 6.7nm to 87.1nm, with an average of 43.3nm.

Abstract: In this paper, the effects of aluminizing agent composition, filler particle size, process parameters and adding impinging particle into aluminizing agent on the thickness of aluminizing layer were investigated. The mechanism of the significant reduction in aluminizing temperature using aluminizing agent was analyzed. The results indicate that the aluminizing temperature can be reduced to 500°C through mechanical energy aided aluminizing. The mechanical energy aids to improve the surface adhesion probability of Al powders on the specimen surface, increases the chemical activity and adhesion strength of Al powders, thus the aluminizing temperature is greatly reduced.

Abstract: Fast tool servo system could achieve precise and efficient processing of fine micro-structure for its fast and accuracy response to input control signal, which will directly affect the processing quality of the workpiece surface. Different structural forms of fast tool servo system have been designed and presented in China and overseas, with which generally low the stiffness and natural frequency, only can be used for the rule and the characteristic scale of the larger surface processing. A fast tool servo system whose thrust was up to 12500N, stiffness was 280N/μm, the natural frequency was more than 3kHz , was developed in this paper, as well as the analytical expression of time domain and frequency domain output，which were presented by the modeling analysis; The unknown parameters of the system model were identified by frequency response test. The theoretical and experimental results indicated that the system has good dynamic performance to meet the fine micro-structure of highly efficient, high-precision processing needs.

Abstract: To have a clear understanding of the effect of electrode resistivity on the in-situ resistivity measurement under high pressure in a diamond anvil cell (DAC), we perform finite element analysis (FEA) to simulate the distribution of the steady current field in sample. The theoretical analysis reveals the origin of the effect. It is caused by the resistivity difference between electrodes and sample. And the more the difference of their resistivity is, the more obvious the effect is. All these will result in large resistivity error. However we find that reducing the resistivity difference between the electrode and sample can improve the results.