1,720,986 research outputs found
Rapid pattern inspection of shadow masks by machine vision integrated with Fourier optics
No full textCopyright 1997 Society of Photo-Optical Instrumentation Engineers.We present a machine vision inspection method that is specially devised to detect defects on shadow masks. This method incorporates Fourier optics to capture only irregular defects in real time by blocking out the periodically repetitive pattern of normal mask holes using a pinhole type spatial filter under coherent illumination. In addition, a fast defect-detection image processing algorithm efficiently suppresses undesirable background noisy images. Experimental results prove that this method provides a detection capability of 500 mu m(2) for the least defect size. (C) 1997 Society of Photo-Optical Instrumentation Engineers
Electrical-properties of Sol-gel Processed PLZT Thin-films
No full textSol-gel processed lanthanum-modified lead zirconate titanate (PLZT) thin films consisting of two different perovskite phase contents were fabricated on indium tin oxide coated Corning 7059 glass substrates with two different heating schedules: direct insertion at 650-degrees-C for 30 min and at 500-degrees-C for 2 h. Optical transmittance spectra, polarization versus electric field curves, relative dielectric constant versus frequency and capacitance versus d.c. bias voltage curves of the samples were investigated. The samples showed a good transparency of over 70% and interference oscillation. A thin film consisting of mainly perovskite phase showed a slim loop hysteresis in the polarization versus electric field curve and in the capacitance versus d.c. bias voltage curve, indicating the presence of ferroelectric domains, but a film consisting of mainly pyrochlore phase did not. The dielectric constant and loss factor of the thin film consisting of mainly perovskite phase were about 90 and about 0.2, respectively, at relatively low frequency and showed dispersion of the dipolar polarization of permanent dipole moment in the ferroelectric perovskite phase in the frequency range between 10 kHz and 1 MHz
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A real-time encoding and decoding system for nonlinear HDTV editor
No full textA real-time encoding and decoding system (REDS) for HDTV that can be used for nonlinear HDTV editing in studio has been developed. The intrapicture coding of motion JPEG is implemented and optimized in the REDS so that a high-quality image can be recovered for the nonlinear editing. The REDS has a parallel architecture with multiple programmable digital signal processors (DSP) and reconfigurable field programmable logic devices (FPLD). The HDTV Image is spatially partitioned and concurrently processed by the multiple processors. The programmable DSPs perform the discrete cosine transform and quantization to reduce the spatial redundancy of the HDTV image, whereas the FPLDs perform the variable length coding to reduce the statistical redundancy. In addition, field-based quantization matrices are developed for HDTV images. The REDS has the programmability and the random accessibility of image frames, the two most Important features for a nonlinear HDTV editing system. (C) 2000 John Wiley & Sons. Inc
Pyroelectric properties of sol-gel derived lanthanum modified lead titanate thin films
No full textLanthanum-modified lead titanate (PLT) thin films were fabricated on Pt/Ti/SiO2/Si substrate using the sol-gel method and rapid thermal annealing technique. The pyroelectric coefficient, and the infrared responsivity and the detectivity of the films were measured using static and dynamic methods, respectively. The ferroelectric properties were also measured. The pyroelectric coefficient increased from 1.3 to 2.5 nC/cm(2) . K with increasing La content. However, these low coefficients of PLT films are due to their crystal quality and orientations. The infrared response properties of PLT films depended on their thermal time constants. tau(t) (thermal time constant) for the PLT films decreased with the La contents increasing. The effects of back surface etching on the responsivity and the detectivity were also discussed.This study was supported by Samsung ElectroMechanics Co., Ltd., Ministry of Science and Technology(MOST) and Korea Science and Engineering Foundation(KOSEF)
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Modeling and Control of a Microthermal Cycler for DNA Polymerase Chain Reaction
No full textWe have developed a microthermal. cycler composed of a microreactor integrated with a platinum sensor/heater and automation equipment/software such as a data acquisition system, a control program, and a graphical user interface. From the control point of view, we have analyzed the dynamic characteristics of the fabricated microreactor and found some interesting dynamic features. On the basis of the analysis, we suggest an appropriate model structure and estimate the model parameters using the prediction error identification method. Requirements for high-performance operation are discussed, and a nonlinear control strategy is proposed to linearize the nonlinear dynamics of the microthermal cycler. We determine the parameters of the nonlinear controller using the optimal tuning method. The developed microthermal cycler shows excellent control performances and performs a successful DNA polymerase chain reaction.
Preparation and waveguiding properties of sol-gel derived lathanum modified lead titanate slab waveguides
No full textUsing sol-gel processing method, thin films of lathanum modified lead titanate (PLT) on Coming 7059 glass were prepared. Differential thermal analysis (DTA/TG) curve of gel powder and infrared spectra (FT-IR) of the films were measured to estimate proper heating schedule, Microstructures of the films were observed using a scanning electron microscope (SEM). The waveguiding properties and the propagation loss were measured using the prism coupling method. Effects of the drying conditions on the refractive indices and the propagation losses of the films were investigated. Experimental results showed that the grain size and the content of residual organics in the film decreased as the drying temperature of the film increased. As the drying temperature increased, the refractive index increased and the propagation loss decreased.The authors sincerely appreciate the financial support from KOSEF(Funding No. : 94-0300-06-01-3
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