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61.
Detailed TSCAP measurements on silicon P+N and N+P diodes confirm the existence of two acceptor levels of nickel lying 0.21 ± 0.01 and 0.41 ÷ 0.01 eV from the valence and conduction bands respectively. Concentration of these centers, their spatial distribution and behaviours after several annealing treatments are also presented. 相似文献
62.
Vittorio Sgrigna Francesco Altamura Simone Ascani Roberto Battiston Raffaele Bencardino Sandor Blasko Aurora Buzzi Marco Casolino Livio Conti Stefano Lucidi Mauro Minori Andrea Papi Piergiorgio Picozza Stefano Rossi Carlo Stagni David Zilpimiani 《Microgravity science and technology》2007,19(5-6):70-74
EGLE is a wide frequency band search- coil magnetometer designed and built at the Roma Tre University. It has been installed onboard the ISS by the Italian astronaut Roberto Vittori on April 25, 2005 within the LAZIO- EGLE experiment carried out during the ENEIDE Soyuz mission. The scope of the experiment is to test EGLE in space and to investigate geomagnetic field variations. The main applications of EGLE are the study of electromagnetic environment inside the ISS, the correlation of magnetic field data with particle fluxes detected by LAZIO particle detector, and the monitoring of ionospheric perturbations possibly caused by Earth seismic activity. Since continuous electromagnetic field measurements on board the ISS are important for diverse space applications, a magnetometer with a suitable design is requested. Appropriate solutions for these applications, which have been adopted by EGLE, are in particular the use of 1- Wire technology and the possibility to detect by means of a search- coil magnetometer a large portion of the ULF frequency band, usually measured by flux- gate probes. To investigate the topside ionosphere electromagnetic environment and stability of Van Allen radiation belts in relation with seismic and anthropogenic electromagnetic emissions, a specific satellite mission (the ESPERIA project) has been designed for the Italian Space Agency (ASI), and up to now a few instruments of its payload have been built and tested in space. One of them is exactly the EGLE search- coil magnetometer. The first magnetic observations performed by this instrument reveal to be promising and demand for a further and deeper analysis based on a longer time series of data. 相似文献
63.
Tilke A. T. Stapelmann C. Eller M. Bach K.-H. Hampp R. Lindsay R. Conti R. Wille W. Jaiswal R. Galiano M. Jain A. 《Semiconductor Manufacturing, IEEE Transactions on》2007,20(2):59-67
In the present work, a high aspect ratio process (HARP) using a new O3/TEOS based sub atmospheric chemical vapor deposition process was implemented as STI gapfill in sub-65-nm CMOS. Good gapfill performance up to aspect ratios greater than 10:1 was demonstrated. Since the HARP process does not attack the STI liner as compared to HDP, a variety of different STI liners can be implemented. By comparing HARP with HDP, the geometry dependence of nand p-FET performance due to STI stress is discussed 相似文献
64.
Design of an enhanced access point to optimize TCP performance in Wi-Fi hotspot networks 总被引:1,自引:0,他引:1
In the last years, the number of Wi-Fi hotspots at public venues has undergone a substantial growth, promoting the WLAN technologies
as the ubiquitous solution to provide high-speed wireless connectivity in public areas. However, the adoption of a random
access CSMA-based paradigm for the 802.11 MAC protocol makes difficult to ensure high throughput and a fair allocation of
radio resources in 802.11-based WLANs. In this paper we evaluate extensively via simulations the interaction between the flow
control mechanisms implemented at the TCP layer and the contention avoidance techniques used at the 802.11 MAC layer. We conducted
our study considering initially M wireless stations performing downloads from the Internet. From our results, we observed that the TCP downlink throughput
is not limited by the collision events, but by the inability of the MAC protocol to assign a higher chance of accessing the
channel to the base station. We propose a simple and easy to implement modification of the base station’s behavior with the
purpose of increasing the TCP throughput reducing useless MAC protocol overheads. With our scheme, the base station is allowed
to transmit periodically bursts of data frames towards the mobile hosts. We design a resource allocation protocol aimed at
maximizing the success probability of the uplink transmissions by dynamically adapting the burst length to the collision probability
estimated by the base station. By its design, our scheme is also beneficial to achieve a fairer allocation of the channel
bandwidth among the downlink and uplink flows, and among TCP and UDP flows. Simulation results confirm both the improvement
in the TCP downlink throughput and the reduction of system unfairness. 相似文献
65.
Anastasia Dobroskok 《International Journal of Fracture》2001,111(3):41-46
A new efficient iterative procedure to follow automatically crack trajectory is suggested. Parameters of the procedure and illustrative examples are given. 相似文献
66.
Acquiring writing revision and self-regulatory skill through observation and emulation. 总被引:1,自引:0,他引:1
The influences of modeling and social feedback on the acquisition of writing revision were studied with 72 college students. Students watching a coping female model gradually improving her writing technique on a sentence-combining task were hypothesized to surpass students observing a mastery model perform the technique flawlessly on a writing-skill measure and an array of self-regulatory measures, such as self-satisfaction reactions, self-efficacy perceptions, and intrinsic interest in the task. Students observing a mastery model were expected, in turn, to surpass those learning without the benefit of modeling on these same measures. Support for both hypotheses was found. Social feedback during enactive performance assisted learners from all modeling groups in acquiring writing and self-regulatory skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
Quadratically nonlinear waveguides are studied in the presence of a Bragg grating resonant with one of the involved frequencies. In the case of second-harmonic generation and distributed feedback at the fundamental, we investigate the existence and features of two-color gap-solitary waves, focusing on controlling their propagation speed. This leads to the conception of optically controlled delay lines and retiming schemes for pulse streams in communication systems 相似文献
68.
Multihop Ad Hoc Networking: The Reality 总被引:1,自引:0,他引:1
In this article we show that, although pure general-purpose MANET (mobile ad hoc networks) does not yet exist in the real world, the multihop ad hoc networking paradigm was successfully applied in several classes of networks that are penetrating the mass market. We present as examples mesh, opportunistic, vehicular, and sensor networks, where the multi-hop ad hoc paradigm is applied in a pragmatic way to extend the Internet and/or to support well-defined application requirements. We contrast these successful areas of ad hoc networking to the lack of impact of pure general-purpose MANET, demonstrating how a more pragmatic approach is a winner 相似文献
69.
Performance of New Biodegradable Di‐Sulfonate Surfactants as Hydrotropes in High‐Temperature and Salinity Environments 下载免费PDF全文
Anastasia Mardilovich Behr Christopher J. Tucker Edward D. Daugs 《Journal of surfactants and detergents》2015,18(2):329-338
Propyl alkyl ether sulfonate (PAES) surfactants, recently developed by The Dow Chemical Company, show excellent electrolyte, hard water and caustic solubility, with attractive ECOTOX profile and biodegradability. Due to their unique structure and properties, they are good candidates for use as hydrotropes in formulations containing nonionic surfactants. The goal of these studies was to evaluate hydrotropic efficiency of PAES materials via cloud point analysis. The effects of PAES alkyl tail length, concentration, and mono‐ and di‐sulfonate components on the cloud point of TERGITOL? 15‐S‐9 in solutions of varying electrolyte strength were investigated. In the presence of high electrolyte levels, PAES 12C had the highest hydrotropic efficiency of all materials tested, including commonly used commercial hydrotropes. Di‐sulfonate components of the PAES materials were found to be more efficient hydrotropes than mono‐sulfonate in high electrolyte environments for all tail lengths tested. The di/mono ratio and tail length were found to be critical parameters. 相似文献
70.
Monitoring the oxidative stability and volatiles in blanched,roasted and fried almonds under normal and accelerated storage conditions by DSC,thermogravimetric analysis and ATR‐FTIR 下载免费PDF全文