High-Frequency Light Rectification by Nanoscale Plasmonic Conical Antenna in Point-Contact-Insulator-Metal Architecture

Numerous efforts have been undertaken to develop rectifying antennas operating at high frequencies, especially dedicated to light harvesting and photodetection applications. However, the development of efficient high frequency rectifying antennas has been a major technological challenge both due to a lack of comprehension of the underlying physics and limitations in the fabrication techniques. Various rectification strategies have been implemented, including metal-insulator-metal traveling-wave diodes, plasmonic nanogap optical antennas, and whisker diodes, although all show limited high-frequency operation and modest conversion efficiencies. Here a new type of rectifying antenna based on plasmonic carrier generation is demonstrated. The proposed structure consists of a resonant metallic conical nano-antenna tip in contact with the oxide surface of an oxide/metal bilayer. The conical shape allows for an improved current generation based on plasmon-mediated electromagnetic-to-electron conversion, an effect exploiting the nanoscale-tip contact of the rectifying antenna, and proportional to the antenna resonance and to the surface-electron scattering. Importantly, this solution provides rectification operation at 280 THz (1064 nm) with a 100-fold increase in efficiency compared to previously reported results. Finally, the conical rectifying antenna is also demonstrated to operate at 384 THz (780 nm), hence paving a way toward efficient rectennas toward the visible range

Excitation and decay of projectile-like fragments formed in dissipative peripheral collisions at intermediate energies

Projectile-like fragments (PLF:15<=Z<=46) formed in peripheral and mid-peripheral collisions of 114Cd projectiles with 92Mo nuclei at E/A=50 MeV have been detected at very forward angles, 2.1 deg.<=theta_lab<=4.2 deg. Calorimetric analysis of the charged particles observed in coincidence with the PLF reveals that the excitation of the primary PLF is strongly related to its velocity damping. Furthermore, for a given V_PLF*, its excitation is not related to its size, Z_PLF*. For the largest velocity damping, the excitation energy attained is large, approximately commensurate with a system at the limiting temperatureComment: 5 pages, 6 figure

Tracing a phase transition with fluctuations of the largest fragment size: Statistical multifragmentation models and the ALADIN S254 data

A phase transition signature associated with cumulants of the largest fragment size distribution has been identified in statistical multifragmentation models and examined in analysis of the ALADIN S254 data on fragmentation of neutron-poor and neutron-rich projectiles. Characteristics of the transition point indicated by this signature are weakly dependent on the A/Z ratio of the fragmenting spectator source. In particular, chemical freeze-out temperatures are estimated within the range 5.9 to 6.5 MeV. The experimental results are well reproduced by the SMM model.Comment: 7 pages, 3 figures, Proceedings of the International Workshop on Multifragmentation and Related Topics (IWM2009), Catania, Italy, November 2009

Comprehensive assessment of sequence variation within the copy number variable defensin cluster on 8p23 by target enriched in-depth 454 sequencing

<p>Abstract</p> <p>Background</p> <p>In highly copy number variable (CNV) regions such as the human defensin gene locus, comprehensive assessment of sequence variations is challenging. PCR approaches are practically restricted to tiny fractions, and next-generation sequencing (NGS) approaches of whole individual genomes e.g. by the 1000 Genomes Project is confined by an affordable sequence depth. Combining target enrichment with NGS may represent a feasible approach.</p> <p>Results</p> <p>As a proof of principle, we enriched a ~850 kb section comprising the CNV defensin gene cluster DEFB, the invariable DEFA part and 11 control regions from two genomes by sequence capture and sequenced it by 454 technology. 6,651 differences to the human reference genome were found. Comparison to HapMap genotypes revealed sensitivities and specificities in the range of 94% to 99% for the identification of variations.</p> <p>Using error probabilities for rigorous filtering revealed 2,886 unique single nucleotide variations (SNVs) including 358 putative novel ones. DEFB CN determinations by haplotype ratios were in agreement with alternative methods.</p> <p>Conclusion</p> <p>Although currently labor extensive and having high costs, target enriched NGS provides a powerful tool for the comprehensive assessment of SNVs in highly polymorphic CNV regions of individual genomes. Furthermore, it reveals considerable amounts of putative novel variations and simultaneously allows CN estimation.</p

A Feasibility Study of an Integral PWR for Space Applications

Fission space power systems are well suited to provide safe, reliable, economic and robust energy sources, in the order of 100 KWe. A preliminary feasibility study of a nuclear fission reactor is here presented with the following requirements: i) high reliability, ii) R&D program of moderate cost, iii) to be deployed within a reasonable period of time (e.g. 2015), iv) to be operated and controlled for a long time (10 years) without human intervention, v) possibly to be also used as a byproduct for some particular terrestrial application (or at least to share common technologies), vi) to start with stationary application. The driving idea is to extend as much as possible the PWR technology, by recurring to an integral type reactor. Two options are evaluated for the electricity production: a Rankine steam cycle and a Rankine organic fluid cycle. The neutronics calculation is based on WIMS code benchmarked with MCNP code. The reactivity control is envisaged by changing the core geometry. The resulting system appears viable and of reasonable size, well fit to the present space vector capabilities. Finally, a set of R&D needs has been identified: cold well, small steam turbines, fluid leakage control, pumps, shielding, steam generator in low-gravity conditions, self pressurizer, control system. A R&D program of reasonable extent may yield the needed answers, and some demanding researches are of interest for the new generation Light Water Reactors

Coulomb fragmentation and Coulomb fission of relativistic heavy-ions and related nuclear structure aspects

The Coulomb excitation of 208Pb projectiles has been studied at an energy of 640 A MeV. Cross sections for the excitation of the two-phonon giant dipole resonance were measured for different targets, and show clear evidence for a two-step electromagnetic excitation mechanism. The experimental cross sections exceed those calculated in the harmonic oscillator approximation by a factor of 1.33 ± 0.16. The deduced 27-decay probability is consistent with the expectation in the harmonic limit. Finally, the excitation of the two-phonon giant dipole resonance in the deformed and fissile nucleus 238U is discussed

Comparison of Three Targeted Enrichment Strategies on the SOLiD Sequencing Platform

Despite the ever-increasing throughput and steadily decreasing cost of next generation sequencing (NGS), whole genome sequencing of humans is still not a viable option for the majority of genetics laboratories. This is particularly true in the case of complex disease studies, where large sample sets are often required to achieve adequate statistical power. To fully leverage the potential of NGS technology on large sample sets, several methods have been developed to selectively enrich for regions of interest. Enrichment reduces both monetary and computational costs compared to whole genome sequencing, while allowing researchers to take advantage of NGS throughput. Several targeted enrichment approaches are currently available, including molecular inversion probe ligation sequencing (MIPS), oligonucleotide hybridization based approaches, and PCR-based strategies. To assess how these methods performed when used in conjunction with the ABI SOLID3+, we investigated three enrichment techniques: Nimblegen oligonucleotide hybridization array-based capture; Agilent SureSelect oligonucleotide hybridization solution-based capture; and Raindance Technologies' multiplexed PCR-based approach. Target regions were selected from exons and evolutionarily conserved areas throughout the human genome. Probe and primer pair design was carried out for all three methods using their respective informatics pipelines. In all, approximately 0.8 Mb of target space was identical for all 3 methods. SOLiD sequencing results were analyzed for several metrics, including consistency of coverage depth across samples, on-target versus off-target efficiency, allelic bias, and genotype concordance with array-based genotyping data. Agilent SureSelect exhibited superior on-target efficiency and correlation of read depths across samples. Nimblegen performance was similar at read depths at 20× and below. Both Raindance and Nimblegen SeqCap exhibited tighter distributions of read depth around the mean, but both suffered from lower on-target efficiency in our experiments. Raindance demonstrated the highest versatility in assay design

Coulomb dissociation of 27 P: A reaction of astrophysical interest

The ground-state decay of 26Al(0+) (T 1/2=1.05 7 106) has a shorter life-time than the Universe. The presence of this element in the Galaxy was measured via g-ray spectroscopy, showing that the nucleosynthesis of this element is an ongoing process in stars. The proton-capture reaction 26Si(p,γ) 27P competes with the production of 26Al(0+) by β-decay. Coulomb dissociation of 27P has been suggested as an indirect method to measure radiative-proton capture when the direct reaction is not feasible. Such an experiment was performed at GSI with a secondary 27P beam produced by fragmenting a 36Ar primary beam at 500 A MeV. Two main observables are preliminarily presented in this work: the reaction cross section and the relative-energy spectrum of the outgoing fragments \ua9 Copyright owned by the author(s)