Papers by Keyword: PLD

Abstract: Data collection in the important position of modern industrial production and scientific research is increasingly outstanding, as well as the real-time collection, real-time transmission and real-time processing of high speed data acquisition requirements are constantly improve. In addition, for different occasions, the data acquisition system of data sampling parameters are different. PLD as a universal integrated circuit, its logic function according to user's programming on the device, this paper introduces the high-speed data acquisition system based on PLD, mainly expounds the software design of the system, this paper introduces a simple PLD system, using FPGA as the data acquisition chip, the main measure the infrared remote control code acquisition, based on EDA technology to design a core, using DMA access to data, to achieve high-speed system requirements.

Abstract: Textile vascular prostheses ARTECOR were coated by laser with amorphous diamond-like carbon layers (DLC) with thickness up to 200 nm. Layers were created in 0.25 Pa of Argon at laser energy density of 8 or 22 Jcm-2. Depending on the deposition conditions, DLC properties moved from soft „graphitic“ to more „diamond“ (53 % of sp3 bonds). Coated prostheses of various DLC thickness and sp3 content were implanted into carotid artery of Merino sheep. The prostheses were extirpated after 100 days (~180 days). From preliminary results follows that prostheses coated with DLC layer thickness of 20 nm and higher sp3 content showed the best results.

Abstract: GaN thin films have been deposited on Si (111) substrates by pulsed laser deposition (PLD) of a GaN target in nitrogen atmosphere. An Nd: YAG pulsed laser with a wavelength of 1064 nm was used as a laser source. The results indicate that the GaN thin films deposited only by PLD are amorphous. By annealing in an NH3 atmosphere, the quality of the GaN thin films is improved, and the crystallzinity GaN thin films were obtained. The influence of annealing temperature on the crystallinity, structure, surface morphology and optical properties of GaN films have been examined by X-ray diffraction (XRD), atomic force microscopy (AFM) and infrared spectrum. In our experimental conditions, the GaN thin films deposited by PLD with a laser energy of 250 mJ, growth temperature of 800 °C and annealed at 1000 °C have the best surface morphology and crystalline quality.

Abstract: High Tc superconducting tapes based on YBCO Coated Conductor have been extensively studied to develop the processing techniques for application. In this paper, two self-designed reel-to-reel deposition systems (Sputtering and PLD) were installed. Continuous deposition of multi-layer CeO2/YSZ/Y2O3 buffer layers were carried out on biaxially textured NiW substrate using reactive sputtering. YBCO films were coated on the CeO2/YSZ/Y2O3 buffered NiW substrate by continuous PLD subsequently. To achieve high current carrying capacities, combinations of various deposition conditions were explored. X-ray diffraction measurements show good in-plane and out-plane texture in buffer layers and YBCO films. The transition temperature of the YBCO was 89 K and the critical current is over 50 A at 77 K in 1 meter long YBCO tapes.

Abstract: TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.

Abstract: MgO thin films were deposited by Pulsed Laser deposition using different process parameter. The characteristics were investigated via X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and Digital Holographic Microscope (DHM). It is found that the thin film surface morphology and thickness are different. It was found that the different process parameters such as chamber gas pressure, substrate temperature, LASER energy and number of pulses greatly influence the characteristics of the thin films obtained. The thin films have very low thicknesses of 97, 187 and 193 nm.

Abstract: Nanoparticles of bismuth ferrite (BiFeO3) were fabricated by high-pressure pulsed laser deposition method (PLD) on Pt-coated Si substrates. Effects of the ambient oxygen pressure during deposition (from 1 Torr to 15 Torr) were studied with respect to the microstructures and magnetic properties of the samples. It was found that as the pressure is higher than 5 Torr isolated nanoparticles are formed and the size of these nanoparticles decreases with the deposition pressure. All the nanoparticles exhibit ferromagnetic behavior and the magnetic coercive filed decreases with the particle size.

Abstract: We usually adopt DSP and ARM to perform signal collection and processing. However, functions of DSP and ARM largely depend on the software. Parameter modulation of the software must account for sampling time partly. Moreover, software can not control complex peripheral logic circuit very well. The above problems render DSP and ARM containing big flaws in high-speed data collection and processing. Field-programmable Gate Array (FPGA) possesses the characteristics of timeliness, controllability and rapid processing speed. The paper designed a new circuit based on FPGA to obtain high-speed signal, and utilized FFT IP core in FPGA to perform spectral analysis with the help of digital signals from the circuit. The paper introduced the design based on FPGA and verified that it possesses good performance according to actual experiments.

Abstract: Gallium or sulphur additions in CuInSe₂ were prepared using RF magnetron sputtering and pulsed laser deposition respectively. All of the observed thin films show a chalcopyrite structure with the S addition increases the favourable (112) peak. The optical absorption coefficients were slightly decreased. The films energy band gap could be shifted from 1.04 to 1.68eV by adjusting the mole ratio of S/(S+Se) and In/(In+Ga). It is possible to obtain the optimum energy band gap by adding S solute or Ga at a certain ratio in favour of Se and In respectively. It is also necessary to control the ratio of Ga and S additions and to retain a certain portion of In to provide better properties of CIS films.