Abstract: A novel fused biconical taper system is developed based on electrical heating system. Its movement platforms are designed. The main drawing movement platform, heater movement platform and packaging movement platform are focused on analysis. Motion control program is developed based on Delphi 2006 according to its technological requirements. The experimental results show that the movement of the novel fused biconical taper system is very stable, and the optical fiber couplers fabricated with the novel system have the good optical performance and the good consistency in particular.
Abstract: In the present paper, we have not only investigated the top surface and cross-section morphology, but also measured photoluminescence spectra characteristic of porous silicon after deposition of metallic ions by electrochemical deposition employing scanning electron microscopy (SEM) and spectrometer, respectively. It is apparent from the SEM images that the microstructure of porous silicon is seriously ruined by the metallic ions deposited by electrochemical deposition. Most interesting is the finding that in the photoluminescence spectrum of porous silicon after the deposition of metallic ions such as AL3+ and Cu2+, the luminescence band gradually is quenched as the electrochemical deposition progressed. A careful consideration of the results obtained show that according to the basic theory of well-established quantum confinement model, the quenching of photoluminescence spectra of porous silicon may well be attributed to the microstructure fell into ruin. On the other side of the fence, we can interpret the physical origin of the phenomenon in view of the presence of metallic ions which give rise a series of energy level deep in the band gap of porous silicon.
Abstract: A novel polyelectrolyte (PLJY) was synthesized based on the azobenzene chromophore containing functional groups (-C=C-) and α-methacrylic acid by radical polymerization. The PLJY was characterized by FT-IR and UV-vis spectroscopy. The thermal property was characterized using the differential scanning calorimeter (DSC). The glass transition temperatures (Tg) was 179.1 oC and showed that the PLJY had excellent thermal stability. Influences of pH values on the UV-Vis absorption spectra of PLJY were studied and polyelectrolyte solution had good pH-sensitivity and H-aggregation behavior. The photoresponsive and thermochromism behaviors were investigated for the azo polyelectrolyte PLJY solution or film. By 256 nm excitation wavelength, the PLJY solution or film appeared photo responsive behavior. At high temperature, the PLJY solution had thermochromic behavior. These results showed that the polyelectrolyte had potential applications in optical information storage and optical switch.
Abstract: This study examined the effect of crystalline orientation and dopants such as Nb and Zn on the piezoelectric coefficient of sol-gel driven Pb1(Zr0.52Ti0.48)O3(PZT) and doped PZT thin films. Crack-free 1-μm-thick PZT and doped PZT thin films prepared by using 2-Methoxyethanol-based sol-gel method were fabricated on Pt/Ti/SiO2/Si substrates. The highly (111) oriented PZT thin films of pure perovskite structure could be obtained by controlling various parameters such as a PbTiO3 seed layer and a concentration of sol-gel solution. The Nb-Zn doped PZT thin films exhibited high piezoelectric coefficient which was about 50 % higher than that of undoped PZT thin film. The highest measured piezoelectric coefficient was 240 pC/N, which could be applicable to piezoelectrically operated MEMS actuator, sensor, or energy harvester devices.
Abstract: Amorphous silicon (a-Si) film crystallized by Ni-induced lateral crystallization under static electric field was analyzed. It has been demonstrated that Ni-induced lateral crystallization of a-Si is directional with electric field. Moreover, there exists a critical value of electric field strength, below which the rate of Ni-induced lateral crystallization of a-Si increases remarkably with the increase of field strength, while above which the rate will decrease instead. This phenomenon can be interpreted well based on electromigration effect.
Abstract: The electronic structures of oligomers of pyrrole have been calculated using the extended Hückel tight-binding program. The energy diagrams are shown for oligomers as the number of the repeating unit in the oligomers increases from 1 to 16. The relationship between the energy gap of the oligomers and the number of the repeating unit in the oligomers is established. Blue-green photoluminescence and electroluminescence from one-dimensional polypyrrole are predicted.
Abstract: A novel linear conjugated polymer, poly(cyclopenta-1,3-diene), is designed. The electronic structures of poly(cyclopenta-1,3-diene) is calculated with extended Hückel tight binding program. The calculated band gap of the polymer is about 1.1 eV, which suggests this kind of conjugated polymer can be used in infrared optoelectronic devices.
Abstract: A series of polypyrrole samples were synthesized by oxidizing pyrrole in the aqueous medium of ferric chloride, and the relation between oxidant/monomer ratio and the electrical conductivity of polypyrrole was studied by increasing the ratio from 0.25:1 to 2.5:1. Our results showed that the conductivity of polypyrrole was dependent on the mole ratio of the oxidant to pyrrole, and a maximum value for electrical conductivity of 1500 S/m was achieved for a ratio of 0.75:1.
Abstract: The main aspects for the test of system on chip (SoC) are designing testability architectures and solving the test scheduling. The test time of SoC can be reduced by using good test scheduling schemes. A test scheduling method based on cellular genetic algorithm is presented in this paper. In the method, the individuals are used to represent the feasible solutions of the test scheduling problem, the individuals are distributed over a grid or connected graph, the genetic operations such as selection and mutation are applied locally in some neighborhood of each individual. The test scheduling schemes are obtained by carrying out the evolutionary operations for the populations. A lot of experiments are performed for the SoC benchmark circuits, the experimental results show that the better test scheduling schemes can be obtained by the method in this paper.
Abstract: The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Being nonhygroscopic, ammonium persulfate was used as the oxidant. Under the condition of fixed molar ratio of oxidant-to-monomer (0.375:1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.375:1.00.