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61.
Cong Viet Phan Hervé Di Benedetto Cédric Sauzéat Josselin Dayde Simon Pouget 《Fatigue & Fracture of Engineering Materials & Structures》2017,40(12):2169-2182
Quantification of different effects (nonlinearity, heating, thixotropy, and fatigue) occurring during fatigue tests on bituminous mixtures is presented in this paper. A focus is given on the nonlinearity phenomenon. Continuous fatigue tests and a test with specific protocol (called fatigue tests to estimate biasing effects) were performed in tension/compression mode on cylindrical samples of the same material. The analysis of results reveals that reversible effects (nonlinearity, heating, and thixotropy) are important (more than 90% decrease at 100,000 cycles for a strain amplitude of 100 μm/m at 10 Hz) and cannot be ignored when interpreting classical fatigue tests. The nonlinearity effects respect the time‐temperature superposition principle, and they are more pronounced at “high” temperature (at the same frequency). Direction of nonlinearity curve in the Cole‐Cole axes is shown to be independent of temperature and frequency for the considered range. 相似文献
62.
Effect of Extended Surfactant Structure on Interfacial Tension and Microemulsion Formation with Triglycerides 总被引:1,自引:0,他引:1
T. T. Phan C. Attaphong D. A. Sabatini 《Journal of the American Oil Chemists' Society》2011,88(8):1223-1228
In this work, the impacts of extended surfactant structure (number of polypropylene oxide PO groups and branching nature of the hydrocarbon chain) on microemulsion formation and IFT values were examined with triglyceride oils. The results show that branching of the hydrocarbon tail of extended surfactants lowers optimum salinity and IFT values. The results also show that for the surfactants studied ultralow IFTs and microemulsion formation with vegetable oils can be achieved using extended surfactants with at least eight PO groups. 相似文献
63.
64.
Raphael C.-W. Phan Jiang Wu Khaled Ouafi Douglas R. Stinson 《Wireless Personal Communications》2011,61(1):69-81
In this paper, we analyze the first known provably secure Radio Frequency Identification (RFID) authentication schemes that
are designed to provide forward untraceability and backward untraceability: the L-K and S-M schemes. We show how to trace
tags in the L-K scheme without needing to corrupt tags. We also show that if a standard cryptographic pseudorandom bit generator (PRBG) is used in the S-M scheme, then the scheme may fail to provide forward untraceability
and backward untraceability. To achieve the desired untraceability features, we show that the S-M scheme can use a robust PRBG which provides forward security and backward security. We also note that the backward security is stronger than necessary
for the backward untraceability of the S-M scheme. 相似文献
65.
66.
Finding a large set of single DNA strands that do not crosshybridize to themselves and/or to their complements is an important
problem in DNA computing, self-assembly, and DNA memories. We describe a theoretical framework to analyze this problem, gauge
its computational difficulty, and provide nearly optimal solutions. In this framework, codeword design is reduced to finding large sets of strands maximaly separated in a DNA space and the size of such sets depends on the geometry
of these metric spaces. We show that codeword design is NP-complete using any single reasonable measure that approximates the Gibbs energy, thus practically excluding the possibility
of finding any procedure to find maximal sets efficiently. Second, we extend a technique known as shuffling to provide a construction
that yields provably nearly-maximal codes. Third, we propose a filtering process that removes strands creating pairs with
low Gibbs energies, as approximated by the nearest-neighbor model. These two steps produce large codes of thermodynamic high
quality. The proposed framework can be used to gain an understanding of the Gibbs energy landscapes for DNA strands on which
much of DNA computing and self-assembly are based. 相似文献
67.
T. Masood S. Patterson N.V. Amarasinghe S. McWilliams D. Phan D. Lee Z.A. Hilali Xiong Zhang G.A. Evans J.K. Butler 《Photonics Technology Letters, IEEE》2004,16(3):726-728
Single-frequency 1310-nm grating-outcoupled surface-emitting (GSE) semiconductor lasers with output slope efficiencies exceeding 0.1 mW/mA into multimode fibers, threshold currents below 22 mA, and >30-dB sidemode suppression ratios are reported. These GSE lasers consist of 500-/spl mu/m-long active ridges that excite one end of surface-emitting second-order outcoupling gratings with 200-/spl mu/m-long first-order distributed Bragg reflector gratings terminating the laser cavities at both ends. The grating outcouplers range from 10 to 50 /spl mu/m in length. These lasers have an open eye pattern for nonreturn-to-zero signals at 2.5 Gb/s into single-mode fibers. The full-width half-maximum far-field beam divergences range from 1.5/spl deg/ /spl times/ 8/spl deg/ to 5/spl deg/ /spl times/ 8/spl deg/. 相似文献
68.
In a wireless mobile client-server environment, a mobile user may voluntarily disconnect itself from the Web server to save its battery life and avoid high communication prices. To allow Web pages to be updated while the mobile user is disconnected from the Web server, updates can be staged in the mobile host and propagated back to the Web server upon reconnection. In this paper, we analyze algorithms for supporting disconnected write operations for wireless Web access and develop a performance model to identify the optimal length of the disconnection period under which the cost of update propagation is minimized. The analysis result is particularly applicable to Web applications which allow wireless mobile users to modify Web contents while on the move. We show how the result can be applied to real-time Web applications such that the mobile user can determine the longest disconnection period such that it can still propagate updates to the server before the deadline so that a minimum communication cost is incurred. 相似文献
69.
Ngoc Kim Pham Do Trung Nguyen Bang Tam Thi Dao Kieu Hanh Thi Ta Vinh Cao Tran Van Hieu Nguyen Sang Sub Kim Shinya Maenosono Thang Bach Phan 《Journal of Electronic Materials》2014,43(7):2747-2753
We have investigated the switching behavior of as-deposited CrO x and post-annealed CrO y films by use of a variety of electrodes (top electrode Ag, Ti; bottom electrode Pt, fluorine tin oxide (FTO)). Resistance switching is highly dependent on electrode material and post-annealing treatment. Among Pt devices, I–V hysteresis was observed for the Ag/CrO x /Pt device only; no resistance switching was observed for Ag/CrO y /Pt, Ti/CrO x /Pt, and Ti/CrO y /Pt devices. Among FTO devices, I–V hysteresis was observed for the Ag/CrO x /FTO device whereas I–V hysteresis with the opposite switching direction was observed for Ag/CrO y /FTO, Ti/CrO x /FTO, and Ti/CrO y /FTO devices. The direction of switching depends not only on electrode material but also on post-annealing treatment, which affects the density of grain boundaries. Thus, the density of grain boundaries determines the type of charge carrier involved in the switching process. For as-deposited CrO x films with a high density of grain boundaries Ag filament paths mediated by electrochemical redox reaction were observed, irrespective of bottom electrode material (Pt or FTO). Post-annealed CrO y films with a low density of grain boundaries suppressed electrochemical redox reaction in the Ag/CrO y /Pt device but promoted short-range movement of O2? ions through the bottom interface, resulting in resistance switching in the Ag/CrO y /FTO device. Electrochemical redox reaction-controlled resistance switching occurred solely in oxides with a high density of grain boundaries or dislocations. 相似文献
70.