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991.
992.
993.
Y. Z. Chen G. Csiszár J. Cizek S. Westerkamp C. Borchers T. Ungár S. Goto F. Liu R. Kirchheim 《Metallurgical and Materials Transactions A》2013,44(8):3882-3889
By means of X-ray line profile analysis and positron lifetime spectroscopy, densities of deformation-induced defects in carbon-rich ferrite of a series of cold-drawn pearlitic steel wires with true strains (ε) up to 5 are characterized. It is shown that both the dislocation densities and the vacancy cluster concentrations increase continuously with increasing ε. On the basis of the measured defect densities, values of defect hardening are estimated. The result shows that contributions of the defect hardening to the total tensile strength of the wires reach nearly 40 pct, which is mainly ascribed to the dislocation hardening. Chemical surroundings of the defects in the carbon-rich ferrite are investigated by coincidence Doppler broadening spectroscopy. The association of carbon with the defects in ferrite is demonstrated. 相似文献
994.
We study the best OSPF style routing problem in telecommunication networks, where weight management is employed to get a routing configuration with the
minimum oblivious ratio. We consider polyhedral demand uncertainty: the set of traffic matrices is a polyhedron defined by a set of linear constraints, and a routing is
sought with a fair performance for any feasible traffic matrix in the polyhedron. The problem accurately reflects real world networks, where
demands can only be estimated, and models one of the main traffic forwarding technologies, Open Shortest Path First (OSPF)
routing with equal load sharing. This is an NP-hard problem as it generalizes the problem with a fixed demand matrix, which
is also NP-hard. 相似文献
995.
Cucurbituril homologues are multi-functional macrocycles that can find applications in many areas and have numerous interesting features setting them apart from the other macrocycles. Among them, the ability of one of the cucurbituril homologues, cucurbit[6]uril (CB6), to catalyze 1,3-dipolar cycloaddition in a regiospecific fashion is truly exceptional. Using this feature, small molecules can be clicked together to form complex structures in a very efficient way. Accordingly, in this article we review recent research involving the use of CB6-catalyzed 1,3-dipolar cycloaddition or the click reaction of CB6 in the construction of supramolecular assemblies including rotaxanes, pseudorotaxanes, polyrotaxanes, polypseudorotaxanes, molecular switches, machines, and nanovalves. 相似文献
996.
The topic of this study is the optimization of the preparation procedure and chemical composition of a gas diffusion electrode
(GDE) for utilization in high-temperature PEM fuel cells. A phosphoric acid-doped polybenzimidazole derivative membrane was
used as a polymer electrolyte. The following parameters were studied: nature and content of the polymeric binder (PTFE—hydrophobic,
PBI—hydrophilic) in the catalytic layer (CL) and concentration of platinum in catalytic powder (affecting the thickness of
the CL). Brushing and spraying were selected as the most suitable techniques of CL deposition. Surprisingly, both polymeric
binders investigated in the framework of this study were found to provide a similar GDE performance for CL deposited on the
gas diffusion layer surface by spraying. 相似文献
997.
Nowadays outdoor location systems have been used extensively in all fields of human life from military applications to daily life. However, these systems cannot operate in indoor applications. Hence, this paper considers a novel indoor location system that aims to locate an object within an accuracy of about 2 cm using ordinary and inexpensive off-the-shelf devices and that was designed and tested in an office room to evaluate its performance.In order to compute the distance between the transducers (speakers) and object to be localized (microphone), time-of-arrival measurements of acoustic signals consisting of Binary Phase Shift Keying modulated Gold sequences are performed. This DS-CDMA scheme assures accurate distance measurements and provides immunity to noise and interference.Two methods have been proposed for location estimation. The first method takes the average of four location estimates obtained by trilateration technique. In the second method, only a single robust position estimate is obtained using three distances while the least reliable fourth distance measurement is not taken into account.The system?s performance is evaluated at positions from two height levels using system parameters determined by preliminary experiments. The precision distributions in the work area and the precision versus accuracy plots depict the system performance. The proposed system provides location estimates of better than 2 cm accuracy with 99% precision. 相似文献
998.
999.
ABSTRACT We report on the deposition of Pb(Zrx,Ti1 - x)O3 (PZT) thin films by chemical solution deposition (CSD) on stainless steel foils. The electrical characterization proves good ferroelectric properties with a remnant polarization of 38 μ C/cm2. Since PZT is also piezoelectric the 35 μ m and 50 μ m thick metal foils are used to make piezoelectric actuated cantilever beams of several millimeter lengths. Actuated with 10–30 V a displacement up to 32 μ m was measured in quasi-static mode. In resonance mode the displacement increases several times at the same driving voltage. 相似文献
1000.
Mehmet Turgut Orhan Murat Doğan Selda Keskin Arife Doğan Ali Boztuğ 《The Journal of Adhesion》2013,89(11):927-938
This study investigated the effectiveness of surface treatment of Poly (methyl methacrylate) (PMMA) denture base resin on tensile bond strength between PMMA/silicone-based soft liner. A total of 25 specimens were fabricated and assigned into five groups (n = 5). The surfaces of PMMA were treated with maleic anhydride, maleic anhydride-styrene-vinyl-acetate, n-butylmaleate-styrene-vinyl-acetate, or n-pentamaleate-styrene-vinyl-acetate prior to Primo adhesive primer application and silicone liner placement. The Primo adhesive primer on applied group untreated dentuse base resin served as control. The tensile test was performed using a universal testing machine. Fractured surfaces were observed under Scanning Electron Microscopy (SEM) and spectroscopic interpretation of the interfaces was done by Fourier Transform Infrared (FTIR). Test results showed that surface treatment increased interfacial strength giving the highest value for n-butylmaleate-styrene-vinyl acetate treated group. SEM micrographs revealed that the specimens with n-butylmaleate-styrene-vinyl-acetate and n-penta maleate-styrene-vinyl-acetate terpolymers underwent cohesive failure. FTIR analysis indicated secondary interactions such as hydrogen bonding, possibly on acrylic resin surfaces, caused by the use of maleic anhydride and its terpolymers, and the adhesive. 相似文献