A polymerizable photoredox initiation system for vinyl photopolymerization

A polymerizable photoredox system consisting of 4-methacryl oxbenzophenone (MABP) and N,N-dimethlaminoethyl methacrylate (DMAEMA) used for the photopolymerization of acrylonitrile (AN) was studied. It was found that the polymerization rate is proportional to the 0.93th power for the AN concentration, the 0.28th power for the MABP concentration, and the 0.25th power for the DMAEMA concentration. The overall activation energy of the polymerization obtained is 30.43 kJ/mol. The recorded ESR spectrum indicates that the excited-state MABP abstraets hydrogen mainly from the methyl group of the dimethylamino moiety. The comparison of the initiation ability of polymeric MABP or polymeric DMAEMA with their monomeric forms has also been done and the results indicate that in good solvents P (MABP) has a much higher initiation ability than that of monomeric MABP, but monomeric DMAEMA and P (DMAEMA) display almost the same initiation ability. In poor solvent, the initiation ability of P (MABP) is not so obviously higher than that in good solvents. The result of UV analysis of P (AN) initiated by the MABP–DMAEMA system indicates that both MABP and DMAEMA not only initiate the photopolymerization of AN, but also enter into P (AN) polymer chains. © 1994 John Wiley & Sons, Inc.     

Semiconductor optical amplifier for CWDM operating over 1540-1620 nm

A semiconductor optical amplifier was developed for coarse wavelength-division-multiplexing (CWDM) operating over 1540-1620 nm (C-L band). A unique quantum-well structure was designed to meet the requirements for the CWDM operation such as wide bandwidth, low polarization-dependent gain, and high-saturation power at the short wavelength end of the band (1540 nm). Over the band, 24-dB maximum chip gain was obtained with less than 4.3-dB gain flatness and more than 14.6-dBm saturation power.     

Nd3+ Doped Silicate Glass Photonic Crystal Fiber with Random Hole Distributions

The fabrication of one kind of large core area Nd3 doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB·m-1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.     

Fuzzy control of nitrogen removal in predenitrification process using ORP.

In order to meet increasingly stringent discharge standards, new applications and control strategies for the sustainable removal of nitrogen from wastewater have to be implemented. In the past years, numerous studies have been carried out dealing with the application of fuzzy logic to improve the control of the activated sludge process. In this paper, fuzzy control strategies of predenitrification systems are presented that could lead to better effluent quality and, in parallel, to a reduction of chemicals consumption. Extensive experimental investigations on lab scale plant studies have shown that there was excellent correlation between nitrate concentration and ORP value at the end of the anoxic zone. Results indicated that ORP could be used as an on-line fuzzy control parameter of nitrate recirculation and external carbon addition. The optimal value of ORP to control nitrate recirculation and external carbon addition was - 86 +/- 2 mV and - 90 +/- 2 mV, respectively. The results obtained with real wastewater also showed the good performance and stability of the fuzzy controllers independently from external disturbances. The integrated control structure of nitrate recirculation and external carbon addition in the predenitrification system is also presented.     

Evaluation of accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer

PURPOSE: To evaluate the accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer. METHOD: 58 patients' (113 eyes) intraocular pressure were measured by Keeler, non-contact tonometer and R 900 Goldmann applanation tonometer and the results of measurement of intraocular pressure by the two kinds of tonometers were compared. RESULT: The mean intraocular pressure measured by non-contact is 16.31 +/- 5.59 mmHg and 17.49 +/- 6.13 mmHg (1 mmHg = 0.1333 kPa) by Goldmann applanation tonometer, respectively. There was no statistical significance to be found (P > 0.05) between the two methods. By linear correlation and regression analysis, a positive correlation was found between the two methods (r = 0.8942, b = 0.8154). CONCLUSION: The handheld non-contact tonometer has the same accuracy and reliability of measurement of intraocular pressure comparing with Goldmann applanation tonometer, and it can be used in glaucoma clinic and screening.     

钢纤维聚合物混凝土抗压本构关系

钢纤维聚合物混凝土是由聚合物混凝土基体和钢纤维共同组成的纤维增强复合材料，它的力学行为不仅依赖于聚合物混凝土基体的行为，而且与钢纤维的掺量、分散特征以及钢纤维的几何尺寸有关，本文将基于损伤力学原理研究在不同纤维掺量下的钢纤维聚合物混凝土的全程压力-应变曲线及其本构模型。