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[en] CCD photometry in U, B, and V is presented for a 5' x 3' field in the globular cluster M15. The location of the main sequence in the color-magnitude diagram is found here to be significantly bluer than previous studies have indicated. The luminosity function of the cluster is studied down to V = 22.8 (Mroughly-equal7.5) and shown to be consistent with a power-law mass function, n(M) = QM/sup -alpha/ with α = 2.5 +- 1.0, to the limit of our data. The field star population brighter than V = 21.5, is examined in some detail. There appears to be about 50% more stars belonging to the disk in the field as compared with the Bahcall-Soneira standard galaxy model. The reddening to the cluster is found to be E(B-V) = 0.11 +- 0.04 from nine bright field stars. A new value for the ultraviolet excess of the cluster main-sequence stars is obtained, delta(0.6) = 0.25 +- 0.02, and confirms the well-known fact that M15 is among the metal poorest of the globular clusters
[en] A numerical analysis, backed by analytic solutions for some cases, is used to study the dependence of the base component of current gain and delay time in base implanted bipolar transistors on the base impurity profile. Results are presented in normalised form to facilitate their use in predicting device performance during the processing-device design stage. (author)
[en] In this paper, an approach for expanding the sampled area of a dynamic process by digital holography is reported, where angular, polarization and wavelength multiplexing are applied to record different regions of the sample on a series of sub-holograms overlapped in a single frame of the charge-coupled device. This approach based on a single exposure has special potential for the digital holographic recording of dynamic processes. (paper)
[en] A novel structure for designing and fabricating a power static induction transistor (SIT) with excellent high breakdown voltage performance is presented. The active region of the device is designed to be surrounded by a deep trench to cut off the various probable parasitical effects that may degrade the device performance, and to avoid the parallel-current effect in particular. Three ring-shape junctions (RSJ) are arranged around the gate junction to reduce the electric field intensity. It is important to achieve maximum gate-source breakdown voltage BVGS, gate-drain breakdown voltage BVGD and blocking voltage for high power application. A number of technological methods to increase BVGD and BVGS are presented. The BVGS of the power SIT has been increased to 110 V from a previous value of 50-60 V, and the performance of the power SIT has been greatly improved. The optimal distance between two adjacent ring-shape junctions and the trench depth for the maximum BVGS of the structure are also presented.
[en] A defect-tolerant design is presented for a demultiplexer circuit that is based on threshold logic. The design uses coding both to handle (i.e., tolerate) defects in the circuit and to improve the voltage margin in its gates. The following model is assumed for the defects: configured junctions can become either stuck open or stuck closed, and non-configured junctions can become shorted. Two realizations of the circuit are presented: one using conventional transistor circuitry, and the other using nanoscale components and wiring. The design presented in this paper demonstrates how a standard digital building-block circuit-a demultiplexer-can be efficiently protected against several types of defect simultaneously.
[en] This paper focuses on the design and optimization of different power P-channel LDMOS transistors (VBR > 120 V) to be integrated in a new generation of smart-power technology based upon a 0.18 µm SOI-CMOS technology. Different drift architectures have been envisaged in this work with the purpose of optimizing the transistor static (Ron-sp/VBR trade-off) and dynamic (Ron × Qg) characteristics to improve their switching performance. Conventional single-RESURF P-channel LUDMOS architectures on thin-SOI substrates show very poor Ron-sp/VBR trade-off due to their low RESURF effectiveness. Alternative drift configurations such as the addition of an N-type buried layer deep inside the SOI layer or the application of the superjunction concept by alternatively placing stacked P- and N-type pillars could highly improve the RESURF effectiveness and the P-channel device switching performance
[en] A diagram representation method is proposed to interpret the complicated charge pumping (CP) processes. The fast and slow traps in CP measurement are defined. Some phenomena such as CP pulse rise/fall time dependence, frequency dependence, the voltage dependence for the fast and slow traps, and the geometric CP component are clearly illustrated at a glance by the diagram representation. For the slow trap CP measurement, there is a transition stage and a steady stage due to the asymmetry of the electron and hole capture, and the CP current is determined by the lower capturing electron or hole component. The method is used to discuss the legitimacy of the newly developed modified charge pumping method. (semiconductor devices)
[en] An integrated CMOS high-speed, low power consumption shaper has been designed for the portable digital radiography detector. Analytical simulations of CR-(RC)n semi-Gaussian shaper of various order and shaping time constant were carried out to optimize the timing performance, keeping in mind the stringent requirements of power consumption and equivalent noise charge (ENC). The input differential transistors working in weak inversion are presented to achieve low-power consumption. There is no undershoot by using nested feedback loop. The chip is designed in 0.5 DPDM process by CSMC. Considering a fast signal peaking time of 250 ns, the power consumption is 34.5 μW and the ENC is 453e for a detector of 20 pf. (authors)
[en] A multiaperture spectroscopy device has been installed on the focal reducer at the Cassegrain focus of the Canada-France-Hawaii Telescope. The mask processing and positioning operations are described. Emphasis is placed on the speed and reliability of a fully automatic method controlled by a computer routine. Spectra obtained during the first observations at C.F.H.T. are shown as illustration