88,210 research outputs found
Fluorine in Ge: Segregation and EOR-defects stabilization
No full textIn this paper we investigate the F behavior in Ge during solid phase epitaxy (SPE) and post-SPE annealing. Fluorine implanted with a fluence of 1 x 10(15) F/cm(2) and an energy of 35 key induced the formation of an amorphous Ge layer. Detailed chemical and structural characterizations of the as implanted and annealed samples evidenced a strong segregation of F at the moving amorphous/crystalline interface, leading to a remarkable SPE rate retardation. In addition, we observed that F accumulates in correspondence of the end of range (EOR) defects. The comparison between the thermal evolution of damage produced by self-implantation and F implantation in Ge suggests that F increases significantly the stability of EOR. Such behavior clarifies the role of F in modifying the As diffusion in Ge recently reported in literature. (C) 2011 Elsevier B.V. All rights reserved
A SYSTEM FOR ELECTRICAL SUPPLY TO ELECTRICAL AND/OR ELECTRONIC DEVICES
No full textAn embodiment of the present invention provides a module (50) for electrical connection of electrical and/or electronic devices to a supply base (10), in which the module (50) comprises a casing (51 ) containing winding means of an extractable electric cable (52), which exhibits an end that exits from the casing (51 ) and to which a connector (53) is associated, which connector (53) is destined to couple with a supply socket of an electrical and/or electronic device; the casing (51 ) being conformed such as to removably insert in a housing (18) of the supply base (10), and in which the casing (51 ) comprises an electrical contact (55) connected to the extractable electric cable (52), which is destined to contact a corresponding electrical contact (19) of the supply base (10), when the casing (51 ) is inserted in the housing (18)
A Model for the Analysis at ULS of Corroded RC Beams
No full textThe proposed model is able to consider the interaction between bending, shear and normal forces. Some experimental tests present in the literature, where the structural behaviour of reinforced concrete beams in presence of corrosion of longitudinal and transversal rebar was investigated, were used in the present study in order to validate the proposed model. The numerical results seem to be in good agreement with the experimental ones
TEL62: an integrated trigger and data acquisition board
No full textThe main goal of the NA62 experiment at the CERN SPS is to measure the branching ratio of the ultra-rare K+→π+νν decay, collecting about 100 events in two years of data taking. The experiment puts stringent requirements on the trigger and data acquisition system: the efficient online selection of interesting events and loss-less readout at high rate will be key issues. Readout uniformity of sub-detectors and scalability were taken into account in the architecture design. For this purpose an integrated trigger and data acquisition board (TEL62) was designed; the first prototype is currently under test
Ordering self-assembled islands without substrate patterning
No full textThe self-patterning of the strain field that arises in the growth of stacked multilayers of heteroepitaxial islands, together with the capability of tuning the island size by acting on the deposition temperature, are here exploited to obtain self-organization, resulting in well-ordered clusters composed of regularly disposed, nanosized islands. Our results show that the island spatial distribution can be tuned from a random one to a well-ordered square lattice of island clusters, and that the number of islands inside each cluster can be selected. Moreover, due to the dipole repulsive interaction between adjacent islands, the islands themselves arrange in an ordered fashion inside a single cluster along the same [010]-[100] crystalline directions of the long-range cluster ordering
Modeling, Prototyping, and Testing of Helical Shape Memory Compression Springs With Hollow Cross Section
No full textShape memory alloys (SMAs) are used in many applications as actuators. The main drawbacks that limit the use of the SMAs in the field of mechanical actuation are the low mechanical bandwidth (up to a few Hertzs) and the unsatisfactory stroke (several millimeters). This paper contributes to enhancing the performances of SMA actuators by proposing a new SMA helical spring with a hollow section. The hollow spring is modeled, then it is constructed, and finally it is tested in compression to compare its performances with those of a spring with a solid cross section of equal stiffness and strength. Emptied of the inefficient material from its center, the hollow spring features a lower mass (37% less) and an extremely lower cooling time (four times less) than its solid counterpart. These results demonstrate that helical springs with a hollow construction can be successfully exploited to build SMA actuators for higher operating frequencies and improved strokes
Ultimate Shear of RC Beams with Corroded Stirrups and Strengthened with FRP
No full textTransverse reinforcement plays a key role in the response behavior of reinforced concrete beams. Therefore, corrosion of steel stirrups may change the failure mode of elements from bending to shear, leading to a brittle and catastrophic crisis. It is important to strengthen reinforced concrete beams with corroded stirrups to enhance the shear resistance. This paper presents a formulation, based on the modified compression field theory, to estimate the ultimate shear of reinforced concrete beams strengthened with FRP, because of stirrup corrosion. The detrimental effect of corrosion on steel stirrup yield strength was taken into account by introducing an empirical decay law. The effective strain of FRP reinforcement was adequately evaluated by considering both debonding and tensile stress rupture. The proposed model was validated against collected experimental results, showing a good ability to evaluate shear strength. Moreover, a numerical analysis was carried out to highlight the role of the key parameters predicting the ultimate shear
Urinary high performance reverse phase chromatography cortisol and cortisone analyses before and at the end of a race in elite cyclists
No full textA functional and basic method for the quantitative analysis of urine cortisol (F) and cortisone (E) using a Solid-Phase Extraction column and HPLC with ultraviolet detection is here described and validated to analyse urine samples. Urine specimens were analysed to study F and E relation and ratio in athletes and healthy sedentary subjects. The F and E concentrations in random urine specimens were significantly higher in the post exercise versus pre exercise condition in cyclists (F: 136+/-93 nmol/l versus 67+/-50 nmol/l (p<0.001); E: 797+/-400 nmol/l versus 408+/-252 nmol/l (p<0.001)). The F/E ratio was 0.18+/-0.11 versus 0.16+/-0.07, respectively, and a significant difference was only demonstrated comparing sedentary (0.11+/-0.07) and cyclist individuals at rest (p<0.05)
Fluorine effect on As diffusion in Ge
No full textThe enhanced diffusion of donor atoms, via a vacancy (V)-mechanism, severely affects the realization of ultrahigh doped regions in miniaturized germanium (Ge) based devices. In this work, we report a study about the effect of fluorine (F) on the diffusion of arsenic (As) in Ge and give insights on the physical mechanisms involved. With these aims we employed experiments in Ge co-implanted with F and As and density functional theory calculations. We demonstrate that the implantation of F enriches the Ge matrix in V, causing an enhanced diffusion of As within the layer amorphized by F and As implantation and subsequently regrown by solid phase epitaxy. Next to the end-of-range damaged region F forms complexes with Ge interstitials, that act as sinks for V and induce an abrupt suppression of As diffusion. The interaction of Ge interstitials with fluorine interstitials is confirmed by theoretical calculations. Finally, we prove that a possible F-As chemical interaction does not play any significant role on dopant diffusion. These results can be applied to realize abrupt ultra-shallow n-type doped regions in future generation of Ge-based devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3592962
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