Nonlinear optical side‐chain polymers post‐functionalized with high‐β chromophores exhibiting large electro‐optic property

Electro‐optic side‐chain polymers have been synthesized by the post‐functionalization of methacrylate isocyanate polymers with novel phenyl vinylene thiophene vinylene bridge (FTC) nonlinear optical chromophores. For this application, FTC‐based chromophores were modified in their electronic donor structure, exhibiting much larger molecular hyperpolarizabilities compared with the benchmark FTC. Of these new chromophores, absorption spectra, hyper‐Rayleigh scattering experiment, and thermal analysis were carried out to confirm availability as effective nonlinear optical units for electro‐optic side‐chain polymers. The electro‐optic coefficients (r₃₃) of obtained polymers were investigated in the process of in situ poling by monitoring the temperature, current flow, poling field, and electro‐optic signal. Compared with the nonsubstituted analogue, benxyloxy modified FTC chromophore significantly achieved higher nonlinear optical property, exhibiting molecular hyperpolarizability at 1.9 μm of 4600 × 10^?30 esu and an r₃₃ value of 150 pm/V at the wavelength of 1.31 μm. Synthesized electro‐optic polymers showed high glass transition temperature (T_g), so that the temporal stability examination exhibited >78% of the electro‐optic intensity remaining at 85 °C over 500 h. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Removal of water adsorbed on flouride glass surfaces by NF3 plasma processing

A new method to remove water adsorbed on flouride glass preforms is reported. This method, using NF₃ plasma, can remove surface water on fluoride glasses     

Ignition and increase in Pease limit on current in an ohmically heated high densityZ-pinch

Energetics of an ohmically heated deuterium-tritium high densityZ-pinch has been computed taking into account the energy deposited by the alpha particles produced by fusion. As a result, at higher plasma densities (>10²⁷/m³) and temperatures (>4keV), the pinch current can cross Pease limit and the plasma can get ignited, yielding higher energy gain and neutron yield in a shorter confinement time.     

Phase-controlled atom-photon entanglement in a three-level Λ-type closed-loop atomic system

We study the entanglement of dressed atom and its spontaneous emission in a three-level Λ-type closed-loop atomic system in a multi-photon resonance condition and beyond it.It is shown that the von Neumann entropy in such a system is phase-dependent,and it can be controlled by either the intensity or relative phase of applied fields.It is demonstrated that for the special case of the Rabi frequency of applied fields,the system is disentangled.In addition,we take into account the effect of Doppler broadening on the entanglement and it is found that a suitable choice of laser propagation direction allows us to obtain the steady state degree of entanglement(DEM) even in the presence of the Doppler effect.     

Oxygen production using La0.6Sr0.4Co0.2Fe0.8O3−α (LSCF) perovskite hollow fibre membrane modules

A phase-inversion/sintering technique has been employed in the production of La_0.6Sr_0.4Co_0.2Fe_0.8O_3−α (LSCF) hollow fibre membranes, a bundle of which has then been placed in a high-temperature furnace for production of high purity oxygen from air at temperatures between 980 °C and 1060 °C. By applying a vacuum in the hollow fibre lumens, a product stream containing oxygen purity of 97.15% has been obtained. The downstream vacuum degree higher than 99 kPa shows negligible effect on the oxygen production rate. Studies on long-term operation suggest that the LSCF hollow fibre membranes are less stable for the oxygen production due to the segregation of the constituent membrane elements and the formation of new phases on the outer membrane surfaces. The effect of the operating cycle on the retrogression of membrane performance is much larger than that of duration used in a single cycle.     

Single-mode fused coupler for undersea optical transmission systems

A single mode 3 dB fused coupler, to be used as a redundant laser combiner in the submerged repeater of an undersea optical fibre transmission system, is described. The fabrication and package design of the component for this high reliability application is discussed, and the results of a wide range of environmental tests are given.     

Linear‐dendritic block copolymer hosts for the encapsulation of electro‐optic chromophores via H‐Bonding

Linear‐dendritic block copolymer hosts were synthesized by end‐functionalizing poly(methylmethacrylate) with dendrons that acted as hydrogen‐bonding acceptors for nonlinear optical chromophores. Second harmonic generation experiments indicate that the d₃₃ coefficients and maximum chromophore loading are increased in linear‐dendritic block copolymer hosts over comparable homopolymer hosts. Transmission electron microscopy shows 5–10 nm chromophore domains, confirming the effective spatial dispersion of the chromophores. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5017–5026, 2009     

Influence of ligand type and solution pH on heavy metal ion complexation in cellulosic fibre: model calculations and experimental results

Complexation of heavy metal ions such as Cu²⁺, Zn²⁺ and Co²⁺ by cellulosic fibres cotton, lyocell and viscose was studied in the pH range from pH 7–13. Glycine and sodium D-gluconate complexes were studied. Complex formation in the cellulose matrix depends on ligand, solution pH, complex species formed and type of cellulosic fibre. Species distribution in solution was calculated using the program SPE and literature data for formation constants of M²⁺-glycine and M²⁺-gluconate complexes. The calculated data permit explanation of the experimental heavy metal uptake in the cellulose matrix. In presence of GLY lower heavy metal concentrations were observed. Heavy metal complexation decreases with increasing pH between 7 and 11. For Cu²⁺ and Zn²⁺ a strong increase in metal binding capacity in the fibres was observed at pH 13 for Cu²⁺ and pH 11–12 for Zn²⁺ respectively. Low Zn²⁺ content is analysed at pH 13 due to zincate formation. Member of EPNOE, European Network of Excellence “Polysaccharides” .     

钕玻璃的温敏特性及光纤温度传感器

本文从理论上通过对钕玻璃中Nd～(3+)离子光吸收特性的分析,阐明了其光吸收对温度依从性的原因.在实验中,试制了几种不同类型的钕玻璃光纤温度传感探头.对Nd～(3+)离子光吸收的温度特性进行了验证,其结果和理论分析相一致,实验表明钕玻璃是一种性能良好的光纤温敏传感材料.     

n—型聚乙炔复合膜电极性能的研究

自MacDiarmid等将聚乙炔(PA)做为二次电池的电极材料以来,其电化学特性和行为引起了人们的极大兴趣.随后的研究表明,p-型PA[(CH)~(y )Ay~-]_x在电解液中不稳定,用ClO_4~-掺杂的PA充放循环时有降解发生.n-型PA[My~ (CH)~(y-)]_x(y≤0.10)在THF/LiClO_4电解质中较稳定,电化学还原完全可逆,目前已实现1100次充放循环.因此,它既可做电池的正极材料(碱金属为负极),又可做负极材料(TiS_2为正极).我们发现