Novel triphenylamine unit-containing wholly aromatic polyazomethines were synthesized by the simple solution polycondensation of 4,4′- diaminotriphenylamine with isophthalaldehyde and terephthalaldehyde in m-cresol o...
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Novel triphenylamine unit-containing wholly aromatic polyazomethines were synthesized by the simple solution polycondensation of 4,4′- diaminotriphenylamine with isophthalaldehyde and terephthalaldehyde in m-cresol or in o-chlorophenol at ambient temperature. These polymers were amorphous and had reduced viscosities up to 1.12 dL/g. Orange to red-colored, transparent, and tough films were cast from NMP solutions. The mechanical properties were excellent and their tensile strength, elongation at break, and tensile moduli were in the ranges of 105-112 MPa, 7.1-18.5%, and 2.3-2.8 GPa, respectively. Thermogravimetry showed that these polymers were heat resistant up to around 400°C under nitrogea Doping with iodine markedly increased the electric conductivity and produced the black-colored semiconductive polyazomethines with a maximum conductivity of the order of 10-5 S/cm. Comparison of electronic spectra of the polymers with model compound indicated the π-electrons in the polymers are extensively delocalized along the polymer main chain.
In the transformerless grid connected photovoltaic system, the inverter is the main component. In order to improve the efficiency of the inversion system and achieve a low level of leakage current, several topologies ...
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ISBN:
(纸本)9781509007387
In the transformerless grid connected photovoltaic system, the inverter is the main component. In order to improve the efficiency of the inversion system and achieve a low level of leakage current, several topologies have been applied, among which three level NPC inverter is a kind of popular application. Because the three level NPC inverter has the advantages of low switching losses, good common mode behavior and the small output distortion. This paper proposed a kind of novel three level half bridge NPC inverter with high reliability. The topology only assumes four switches and two diodes with a constant common mode voltage. More importantly, compared to the traditional half bridge NPC inverter, the proposed topology can avoid the shoot through problem without adding the dead time. Also, the novel topology has a lower conduction losses compared to most of the NPC half bridge inverters and the dual buck typed half bridge inverters. The common mode model and the operating principles of the novel topology is analyzed which has verified the advantages. Meanwhile, the three phase structure of the proposed topology is introduced to further illustrate the applications. Finally, the simulation and experimental results illustrated the theoretical findings.
For severe frontal and side impact loads, the passenger compartment of small buses does not retain its initial geometry, and plastic deformations are inevitable. Therefore, linear analysis alone is insufficient for th...
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For severe frontal and side impact loads, the passenger compartment of small buses does not retain its initial geometry, and plastic deformations are inevitable. Therefore, linear analysis alone is insufficient for the analysis and an elasto-plastic analysis technique for evaluating the structural strength capacity and the inelastic deformation characteristics must be considered. A three-dimensional mathematical model of the passenger compartment was prepared using the finite element simulation method. A three-dimensional elasto-plastic structural analysis was developed along with a computer program, named EPSAP, to evaluate the structural strength capacity of the passenger compartment under quasi-static loading conditions. The procedure provides a technique for: (1) tracing the load-displacement history of a space frame structure, (2) determining the collapse or the ultimate load, (3) predicting the collapse mode, and (4) evaluating the energy absorption capacity.
We investigate a stochastic counterpart of majority votes over finite ensembles of classifiers, and study its generalization properties. While our approach holds for arbitrary distributions, we instantiate it with Dir...
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ISBN:
(纸本)9781713845393
We investigate a stochastic counterpart of majority votes over finite ensembles of classifiers, and study its generalization properties. While our approach holds for arbitrary distributions, we instantiate it with Dirichlet distributions: this allows for a closed-form and differentiable expression for the expected risk, which then turns the generalization bound into a tractable training objective. The resulting stochastic majority vote learning algorithm achieves state-of-the-art accuracy and benefits from (non-vacuous) tight generalization bounds, in a series of numerical experiments when compared to competing algorithms which also minimize PAC-Bayes objectives - both with uninformed (data-independent) and informed (data-dependent) priors.
In this paper, we propose a lightweight message transport mechanism for PIAX which can achieves scalable discovery and automatic cooperation of distributed services by the combination of active agents and resource dis...
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In this paper, we propose a lightweight message transport mechanism for PIAX which can achieves scalable discovery and automatic cooperation of distributed services by the combination of active agents and resource discovery function of the overlay network. Realizing ad-hoc cooperation of PIAX, we can actualize the ubiquitous services. However, PIAX messages are too large for ad-hoc communication band. So, to reduce the PIAX message size is required. To reduce message size, we propose a differential condition specification for the discovery messaging and dynamic method ID table sharing. We have implemented the mechanism on a small Linux device with ZigBee communication board and confirmed the effectiveness of our proposal.
Objectives/Scope: The Berdakh-Sudochi region, the promising frontier exploration area of Uzbekistan have been studied for basin modeling to optimize exploration drilling campaign. The objective of this study was to as...
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ISBN:
(纸本)9781959025405
Objectives/Scope: The Berdakh-Sudochi region, the promising frontier exploration area of Uzbekistan have been studied for basin modeling to optimize exploration drilling campaign. The objective of this study was to assess the overall potential of deeper poorly explored Lower Jurassic sequences, based on analyses of field data, regional geological framework and petroleum system. Methods, Procedures, Process: An integrated approach has been applied for petroleum system modeling of the Jurassic sediments in the study area. The basin models have been built based on comprehensive review of all collected regional geological, geophysical, and field data. Interpreted seismic data have been utilized to build the subsurface structural framework of the basin. Distribution of depositional facies have been constrained based on analyses of well logs, seismic attributes, core data and existing regional studies. This basic geological concept served as the main input for assessment of petroleum system elements and reconstruction of burial and thermal histories. Results, Observations, Conclusions: The Jurassic formations in the study area were controlled by the development of the Sudochi paleorift active till Lower Jurassic. Active rifting had dramatic effects on hydrocarbon system. The paleorift provided an effective kitchen for organic maturation in the deeper subsided part of the region. Rapid sedimentation led to deposition of thick basal reservoir rocks at the margins of the basin. The results of regional geological studies and petroleum system modeling showed promising potential for the Lower Jurassic sediments underlying the producing intervals. Reconstructed burial and thermal histories favor the Lower Jurassic in terms of hydrocarbon generation and timing of expulsion. High subsidence rates created favorable conditions for preservation and maturation of distal Lower Jurassic organic-rich sediments, with gas window starting at depth range of 3-4 km. The proximal Lower Jurassi
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