5,573 research outputs found
Physical Characteristics, Sensors and Applications of 2D/3DIntegrated CMOS Photodiodes
Two-dimensional photodiodes are reversely biased at a reasonable voltage whereas 3D photodiodes are likely operated at the Geiger mode. How to design integrated 2D and 3D photodiodes is investigated in terms of quantum efficiency, dark current, crosstalk, response time and so on. Beyond photodiodes, a charge supply mechanism provides a proper charge for a high dynamic range of 2D sensing, and a feedback pull-down mechanism expedites the response time of 3D sensing for time-of-flight applications. Particularly, rapid parallel reading at a 3D mode is developed by a bus-sharing mechanism. Using the TSMC 0.35ÎĽm 2P4M technology, a 2D/3D-integrated image sensor including P-diffusion_N-well_P-substrate photodiodes, pixel circuits, correlated double sampling circuits, sense amplifiers, a multi-channel time-to-digital converter, column/row decoders, bus-sharing connections/decoders, readout circuits and so on was implemented with a die size of 12mmĂ—12mm. The proposed 2D/3D-integrated image sensor can perceive a 352Ă—288-pixel 2D image and an 88Ă—72-pixel 3D image with a dynamic range up to 100dB and a depth resolution of around 4cm, respectively. Therefore, our image sensor can effectively capture gray-level and depth information of a scene at the same location without additional alignment and post-processing. Finally, the currently available 2D and 3D image sensors are discussed and presented
Ascaris phylogeny based on multiple whole mtDNA genomes
Ascaris lumbricoides and A. suum are two parasitic nematodes infecting humans and pigs, respectively. There has been considerable debate as to whether Ascaris in the two hosts should be considered a single or two separate species. Previous studies identified at least three major clusters (A, B and C) of human and pig Ascaris based on partial cox1 sequences. In the present study, we selected major haplotypes from these different clusters to characterize their whole mitochondrial genomes for phylogenetic analysis. We also undertook coalescent simulations to investigate the evolutionary history of the different Ascaris haplotypes. The topology of the phylogenetic tree based on complete mitochondrial genomic sequences was found to be similar to partial cox1 sequencing, but the support at internal nodes was higher in the former. Coalescent simulations suggested the presence of at least two divergence events: the first one occurring early in the Neolithic period which resulted in a differentiated population of Ascaris in pigs (cluster C), the second occurring more recently (~ 900 generations ago), resulting in clusters A and B which might have been spread worldwide by human activities
Excitation Spectrum of the Holstein Model
In this paper the polaron problem for the Holstein model is studied in the
weak coupling limit. We use second order perturbation theory to construct
renormalized electron and phonons. Eigenstates of the Hamiltonian are labelled
and the excitation spectrum is constructed.Comment: 4 pages, revtex, 1 figures, more stuff at
http://www.mpipks-dresden.mpg.de/~robin/robin.htm
A variable star survey of the open cluster M37
A CCD photometric study of the dense galactic open cluster M37 is presented
and discussed. The majority of the analysed data are time-series measurements
obtained through an R_C filter. The observations were carried out on seven
nights between December 1999 and February 2000, and have led to the discovery
of 7 new variable stars in the field. Three of them have been unambiguously
identified as W UMa-type eclipsing binaries, while two more are monoperiodic
pulsating stars, most probably high-amplitude delta Scuti-type variables. The
remaining two stars seem to be long-period eclipsing binaries without firm
period determination. Johnson B and V frames have been used to construct a new
colour-magnitude (CM) diagram of the cluster, and to find the locations of the
new variable stars. The pulsating variables are most likely background objects.
The CM diagram is fitted with recent isochrones yielding the main parameters of
the cluster.Comment: 7 pages, 6 figures, accepted for publication in A&
Land Use/cover Classification for the Proposed Superconducting Super Collider Study Area, Northeastern Illinois
published or submitted for publicationis peer reviewedOpe
Lake Whatcom Monitoring Project 2018/2019 Report
This report describes the results from the 2018/2019 Lake Whatcom monitoring program conducted by the Institute for Watershed Studies at Western Washington University (www.wwu.edu/iws).
The major objectives in 2018/2019 were to continue long-term baseline water quality monitoring in Lake Whatcom and its major tributaries; collect storm runoff water quality data from representative streams in the watershed; and continue collection of hydrologic data from Austin and Smith Creeks
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Near-Surface Vortex Structure in a Tornado and in a Sub-Tornado-Strength Convective-Storm Vortex Observed by a Mobile, W-Band Radar during VORTEX2
Abstract
As part of the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) field campaign, a very high-resolution, mobile, W-band Doppler radar collected near-surface (≤200 m AGL) observations in an EF-0 tornado near Tribune, Kansas, on 25 May 2010 and in sub-tornado-strength vortices near Prospect Valley, Colorado, on 26 May 2010. In the Tribune case, the tornado's condensation funnel dissipated and then reformed after a 3-min gap. In the Prospect Valley case, no condensation funnel was observed, but evidence from the highest-resolution radars in the VORTEX2 fleet indicates multiple, sub-tornado-strength vortices near the surface, some with weak-echo holes accompanying Doppler velocity couplets. Using high-resolution Doppler radar data, the authors document the full life cycle of sub-tornado-strength vortex beneath a convective storm that previously produced tornadoes. The kinematic evolution of these vortices, from genesis to decay, is investigated via ground-based velocity track display (GBVTD) analysis of the W-band velocity data. It is found that the azimuthal velocities in the Tribune tornado fluctuated in concert with the (dis)appearance of the condensation funnel. However, the dynamic pressure drop associated with the retrieved azimuthal winds was not sufficient to account for the condensation funnel. In the Prospect Valley case, the strongest and longest-lived sub-tornado-strength vortex exhibited similar azimuthal velocity structure to the Tribune tornado, but had weaker azimuthal winds. In both cases, the radius of maximum azimuthal wind was inversely related to the wind speed, and changes in the axisymmetric azimuthal component of velocity were consistent with independent indicators of vortex intensification and decay
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