Atomistic quantum transport modeling of metal-graphene nanoribbon heterojunctions

We calculate quantum transport for metal-graphene nanoribbon heterojunctions within the atomistic self-consistent Schr\"odinger/Poisson scheme. Attention is paid on both the chemical aspects of the interface bonding as well the one-dimensional electrostatics along the ribbon length. Band-bending and doping effects strongly influence the transport properties, giving rise to conductance asymmetries and a selective suppression of the subband formation. Junction electrostatics and p-type characteristics drive the conduction mechanism in the case of high work function Au, Pd and Pt electrodes, while contact resistance becomes dominant in the case of Al.Comment: 4 pages, 5 figure

Correlation Between Tumor Extent In Radical Prostatectomies And Preoperative Psa, Histological Grade, Surgical Margins, And Extraprostatic Extension: Application Of A New Practical Method For Tumor Extent Evaluation.

To evaluate a new method designed for estimating the tumor extent in radical prostatectomy specimens. The tumor extent was correlated to preoperative PSA and to several pathologic findings in the surgical specimens as well. Tumor extent was estimated in 118 consecutive radical prostatectomies through a simple point-count method. Drawn on a sheet of paper, each quadrant of the whole mount sections contained 8 equidistant points. During the microscopic slides examination, the tumor area was drawn over the correspondent quadrant of the paper sheet. According to the extent, tumors were classified in 5 groups: 1) very limited: </= 10 positive points; 2) limited: 11-19 positive points; 3) moderately extensive: 20-35 positive points; 4) extensive: 36-39 positive points; 5) very extensive: 70 positive points. This classification was based on a previous analysis of tumor extent in 109 radical prostatectomies. The distribution was quite normal up to 69 positive points, but asymmetric above that number, including cases exceeding far above that value. We considered the quartiles of the normal distribution up to 69 positive points (groups 1 to 4), and above that value a fifth group was considered. There was a statistically significant and direct correlation between the tumor extent and all variables studied: preoperative PSA (p = 0.03), Gleason score (p < 0.0001), primary grade in high-grade tumors (p < 0.01), surgical margins (p < 0.0001), extraprostatic extension (pT3a) (p < 0.0001), and seminal vesicle invasion (pT3b) (p = 0.01). The method, which is simple and well correlated to other prognostic factors, is accessible to those pathologists working in routine pathology laboratories. Whether this method will be used by other urology centers is yet to be seen.29113-9; discussion 12

Low temperature deactivation of Ge heavily n-type doped by ion implantation and laser thermal annealing

International audienceHeavy doping of Ge is crucial for several advanced micro-and optoelectronic applications, but, at the same time, it still remains extremely challenging. Ge heavily n-type doped at a concentration of 1 X 10(20) cm(-3) by As ion implantation and melting laser thermal annealing (LTA) is shown here to be highly metastable. Upon post-LTA conventional thermal annealing As electrically deactivates already at 350 degrees C reaching an active concentration of similar to 4 x 10(19) cm(-3). No significant As diffusion is detected up to 450 degrees C, where the As activation decreases further to similar to 3 x 10(19) cm(-3). The reason for the observed detrimental deactivation was investigated by Atom Probe Tomography and in situ High Resolution X-Ray Diffraction measurements. In general, the thermal stability of heavily doped Ge layers needs to be carefully evaluated because, as shown here, deactivation might occur at very low temperatures, close to those required for low resistivity Ohmic contacting of n-type Ge

An Ensemble of Adaptive Classifiers for Improving Faulty and Drifting Sensor Performance

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Announcement of a special virtual issue on the EuroGRAPHENE program

The Carbon journal is pleased to announce the publication of a virtual special issue on research funded by the EuroGRAPHENE program of the European Science Foundation. In order to ensure rapid publication, the contributed primary research articles have already appeared in regular Carbon volumes over the course of 2014, and are now compiled together as a virtual special issue on the journal website.1 The present article by our team of guest editors serves as an introduction to this special issue, and also a commentary on the graphene field and the important role played by the EuroGRAPHENE program

Temperature- and quantum phonon effects on Holstein-Hubbard bipolarons

The one-dimensional Holstein-Hubbard model with two electrons of opposite spin is studied using an extension of a recently developed quantum Monte Carlo method, and a very simple yet rewarding variational approach, both based on a canonically transformed Hamiltonian. The quantum Monte Carlo method yields very accurate results in the regime of small but finite phonon frequencies, characteristic of many strongly correlated materials such as, e.g., the cuprates and the manganites. The influence of electron-electron repulsion, phonon frequency and temperature on the bipolaron state is investigated. Thermal dissociation of the intersite bipolaron is observed at high temperatures, and its relation to an existing theory of the manganites is discussed.Comment: 12 pages, 7 figures; final version, accepted for publication in Phys. Rev.