Key Engineering Materials Vols. 428-429

Abstract: Universal serial bus (USB) is a kind of new bus interface specification, whose characteristics are convenience, high speed, easiness to expand, low cost and low disturbance, etc. So it is extremely fit to be the communication interface between host computer and peripherals. This paper is mainly about the development of data collecting system based on of USB, including hardware design, firmware design, equipment driver programming and application software design based on Windows driver model (WDM). This system works stable. Both the sampling precision and the data transmission speed have reached expected effect.

Abstract: Amorphous silicon films prepared by PECVD on silex glass substrate has been crystallized by rapid thermal annealing (RTA), From the Raman spectra and scanning electronic microscope (SEM), it was found that the Raman spectra wa best crystallized at 950°C for 5 min. The thin film made by RTA was smoothly and perfect structure.

Abstract: We deposited ZnO films on Corning glass substrate by metal-organic chemical vapor deposition (MOCVD). We found the diffraction (002) peak at ~34.46°, indicating that the ZnO thin films were C-oriented. ZnO films were highly transparent with a transmission ratio larger than 85% in the visible range. The surface morphology of the films was observed by atomic force microscopy (AFM).

Abstract: Organic photovoltaic cells were fabricated by sandwiching p-toluene sulfonic acid doped conducting polymer polypyrrole between indium-tin-oxide cathodes and aluminum anodes. The active polymeric layers could effectively absorb incident photons more than 75 % in the entire spectral region of 250~1100 nm. Upon light exposure, the short-circuit current and the open-circuit voltage were recorded up to 0.6 μA/cm2 and 60 mV, respectively, for the organic photovoltaic cells. The dynamics of the generation and decay of the photocurrent and photovoltage in our organic photovoltaic cells were investigated.

Abstract: Carbon nanotubes used as field emitters, the field emission display with improved insulator was reported. The fabrication process of improved gate structure with the mica plate as insulator between gate-electrode and cathode was presented. The technical development in the design of the improved insulator was also given. The patterned silver slurry was used to form the gate electrode and the screen-printed insulation slurry was formed the gate cover layer. The sealed field emission display packaged by the vacuum-device process had been developed and demonstrated. The modulation of electron emission by the gate voltage was also confirmed. The whole flat display device possessed better field emission properties and high brightness.

Abstract: ZnO films were grown under different oxygen partial pressures by metal organic chemical vapor deposition on the substrates of Corning glass. We investigated the quality of the films by SIEMENS D8 X-ray diffractometer. The surface morphology of the films were observed by Digital Nanoscope ІІІa AFM with normal silicon nitride tip in the contact mode. The hall effect measurements were carried out with indium ohmic contact. The transmission spectrum of the films were measured. The transmission ratio is larger than 80% in the region above the wavelength of 385nm, and sharply decreased under 10% below the wavelength of 375 nm.

Abstract: For studying the effect between short laser pulse and red blood cell (RBC) in a more accurate and powerful way, the light beam characters of a focused femtosecond pulse are studied with a simulation method, and then, a mixed wave-propagating model (MWP) is put forward after analyzing these characters, in which, light beam is thought as propagating in a Gaussian focused shape. In addition, a mathematical processing and linear absorption model in the focused irradiated region of RBC is built based on analyzing its physical mechanism. Finally, the temperature distribution within the RBC is gotten by data simulating calculation, which shows that the temperature variety caused by linear absorption in the focal region is rather small.

Abstract: Color space conversion for color digital camera is a key and difficult technique in the color reproduction information optics. A new color space conversion model based on subsectional fitting to correct color conversion error camera image is presented. First, color error sources and color rendering mechanism are analyzed in theory; then the paper takes standard color target for experimental sample and substitutes color blocks in color shade district for complete color space to solve the difficulties of experimental color blocks selecting; third the model uses subsectional fitting algorithm to built three dimension color conversion curve to correct color conversion error; Finally the experimental results show that the model can color space conversion accuracy of color digital camera and can be used in color conversion for digital camera practically.

Abstract: The influences of frequency, magnetic field density, importing waveform and annealing process on the rangeability of Fe78Si9B13 amorphous alloy ribbon’s magnetic induction effect were studied. The results showed that the rangeability increased with the magnetic field density increased when frequency below 75 kHz, but decreased with the field density increased when frequency over 75 kHz. Compared with quenched ribbons, the rangeability increase after annealed, and the rangeability reached maximum annealed at 300°C for 1.5 hours. When the input waveform is 75 kHz positive pulse and field intensity is 358A/m, the rangeability the quenched ribbons was 2.27V but it reached to 2.85V after annealed at 300°C for 1.5hours.

Abstract: The optical properties and electronic structures of an organic semiconductor sexithiophene have been investigated with ultraviolet-visible spectroscopy, cw photospectroscopy and time-resolved photospectroscopy, respectively. Sexithiophene in dilute tetrahydrofuran solutions can absorb photons at 400 nm while it can give off strong green photoluminescence at 550 nm under the excitation of 325 nm ultraviolet light. With the assistance of calculated electronic structures and pump-and-probe characterization, our results indicate that both the optical absorption and the light emission of the sexithiophene are controlled by the p-conjugation of the oligothiophene.