8,177 research outputs found
Trends and challenges in VLSI technology scaling towards 100 nm
Summary form only given. Moore's Law drives VLSI technology to continuous increases in transistor densities and higher clock frequencies. This tutorial will review the trends in VLSI technology scaling in the last few years and discuss the challenges facing process and circuit engineers in the 100nm generation and beyond. The first focus area is the process technology, including transistor scaling trends and research activities for the 100nm technology node and beyond. The transistor leakage and interconnect RC delays will continue to increase. The tutorial will review new circuit design techniques for emerging process technologies, including dual Vt transistors and silicon-on-insulator. It will also cover circuit and layout techniques to reduce clock distribution skew and jitter, model and reduce transistor leakage and improve the electrical performance of flip-chip packages. Finally, the tutorial will review the test challenges for the 100nm technology node due to increased clock frequency and power consumption (both active and passive) and present several potential solution
Search for Non-Triggered Gamma Ray Bursts in the BATSE Continuous Records: Preliminary Results
We present preliminary results of an off-line search for non-triggered
gamma-ray bursts (GRBs) in the BATSE daily records for about 5.7 years of
observations. We found more GRB-like events than the yield of the similar
search of Kommers et al. (1998) and extended the Log N - log P distribution
down to 0.1 ph cm s. The indication of a turnover of the
log N - log P at a small P is not confirmed: the distribution is straight at
1.5 decades with the power law index -.6 and cannot be fitted with a standard
candle cosmological model.Comment: 4 pages, LaTeX, to appear in Proceedings "Gamma Ray Bursts in the
Afterglow Era", Rome, November 1998, A&AS, 199
Journal Staff
The aluminum–zinc-vacancy (Al Zn −V Zn ) complex is identified as one of the dominant defects in Al-containing n -type ZnO after electron irradiation at room temperature with energies above 0.8 MeV. The complex is energetically favorable over the isolated V Zn , binding more than 90% of the stable V Zn ’s generated by the irradiation. It acts as a deep acceptor with the (0/− ) energy level located at approximately 1 eV above the valence band. Such a complex is concluded to be a defect of crucial and general importance that limits the n -type doping efficiency by complex formation with donors, thereby literally removing the donors, as well as by charge compensation
Power Density Spectra of GRBs
Power density spectra (PDSs) of long gamma-ray bursts (GRBs) provide useful
information on GRBs, indicating their self-similar temporal structure. The best
power-law PDSs are displayed by the longest bursts (T_90>100 s) in which the
range of self-similar time scales covers more than 2 decades. Shorter bursts
have apparent PDS slopes more strongly affected by statistical fluctuations.
The underlying power law can then be reproduced with high accuracy by averaging
the PDSs for a large sample of bursts. This power law has a slope approximately
equal to -5/3 and a sharp break at about 1 Hz.
The power-law PDS provides a new sensitive tool for studies of GRBs. In
particular, we calculate the PDSs of bright bursts in separate energy channels.
The PDS flattens in the hard channel (h\nu>300 keV) and steepens in the soft
channel (h\nu<50 keV), while the PDS of bolometric light curves approximately
follows the -5/3 law.
We then study dim bursts and compare them to the bright ones. We find a
strong correlation between the burst brightness and the PDS slope. This
correlation shows that the bursts are far from being standard candles and dim
bursts should be intrinsically weak. The time dilation of dim bursts is
probably related to physical processes occurring in the burst rather than to a
cosmological redshift.Comment: 9 pages, accepted to Ap
Model Data Fusion: developing Bayesian inversion to constrain equilibrium and mode structure
Recently, a new probabilistic "data fusion" framework based on Bayesian
principles has been developed on JET and W7-AS. The Bayesian analysis framework
folds in uncertainties and inter-dependencies in the diagnostic data and signal
forward-models, together with prior knowledge of the state of the plasma, to
yield predictions of internal magnetic structure. A feature of the framework,
known as MINERVA (J. Svensson, A. Werner, Plasma Physics and Controlled Fusion
50, 085022, 2008), is the inference of magnetic flux surfaces without the use
of a force balance model. We discuss results from a new project to develop
Bayesian inversion tools that aim to (1) distinguish between competing
equilibrium theories, which capture different physics, using the MAST spherical
tokamak; and (2) test the predictions of MHD theory, particularly mode
structure, using the H-1 Heliac.Comment: submitted to Journal of Plasma Fusion Research 10/11/200
Effect of crystal orientation on the implant profile of 60 keV Al into 4H-SiC crystals
The effect of crystal orientation on the implant profile of 60 keV Al into 4H-SiC crystals was analyzed. The [112Ì„0] channel was found to exhibit the deepest channeling with a maximum penetration depth 45 times greater than the projected range of the ranThe authors
acknowledge the STINT ~Swedish Foundation for international
cooperation in research and higher education! program
and Australian Research Council for support under the Discovery
grant and fellowship program
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