Waveform diversity based sonar system for target localization

A new monostatic army system taking advantage of diverse waveforms to improve the performance of underwater target localization is proposed.Unlike the coherent signals between different elements in common active array,the transmitted signals from different elements here are spatially orthogonal waveforms which allow for array processing in the transit mode and result in an extension of array aperture.The mathematical derivation of Capon estimator for this sonar system is described in detail.And the performance of this orthogonal-waveform based sonar is analyzed and compared with that of its phased-array counterpart by water tank experiments.Experimental results show that this sonar system could achieve 12 dB-15 dB additional array gain over its phased-array counterpart,which means a doubling of maximum detection range.Moreover,the angular resolution is significantly improved at lower SNR.     

Frequency stabilization and linewidth narrowing with modulation transfer spectroscopy

We report laser frequency stabilization with modulation transfer spectroscopy (MTS) on ⁸⁵Rb atoms. With both PZT (piezo-electric transducer) slow-loop feedback and current fastloop feedback to the laser head, we get a linewidth narrowing less than 5 kHz simultaneously. Laser injection to a laser diode and frequency beating with another polarization spectroscopy based stabilization setup are also employed to check the narrow linewidth property. With the help of the technique, a linewidth around kHz-level laser is obtained and pave the way for the locking of the lattice laser of ytterbium clock with transfer cavity technique. The setup can be used as a frequency reference for precise frequency control of atomic clock system.     

Three-dimensional interconnected cobalt oxide-carbon hollow spheres arrays as cathode materials for hybrid batteries

Hierarchical porous metal oxides arrays is critical for development of advanced energy storage devices. Herein, we report a facile template-assisted electro-deposition plus glucose decomposition method for synthesis of multilayer CoO/C hollow spheres arrays. The CoO/C arrays consist of multilayer interconnected hollow composite spheres with diameters of ～350 nm as well as thin walls of ～20 nm. Hierarchical hollow spheres architecture with 3D porous networks are achieved. As cathode of high-rate hybrid batteries, the multilayer CoO/C hollow sphere arrays exhibit impressive enhanced performances with a high capacity (73.5 mAh g?1 at 2 A g?1), and stable high-rate cycling life (70 mAh g?1 after 12,500 cycles at 2 A g?1). The improved electrochemical performance is owing to the composite hollow-sphere architecture with high contact area between the active materials and electrolyte as well as fast ion/electron transportation path.     

Characteristics of dry friction backward whirl-A self-excited oscillation in rotor-to-stator contact systems

In this paper, the response characteristics of dry friction backward whirl of a general rotor/stator model, which accounts for both the dynamics of the rotor and the stator as well as the friction and the deformation at the contact surfaces, are investigated. The existence boundaries and the whirl frequencies of the dry friction backward whirl are determined analytically. It is found that there are two or three existence boundaries of the dry friction backward whirl that usually form two existence regions, ...     

Comparison of short period InAs/GaSb superlattices on GaSb and GaAs substrates

Type Ⅱ superlattices(SLs) short period InAs(4ML)/GaSb(8ML) were grown by molecular-beam epitaxy on lattice-mismatched GaAs substrates and on GaSb substrates.A smooth GaSb epilayer was formed on GaAs substrates by inserting mulit-buffer layers including an interfacial misfit mode AlSb quantum dot layer and AlSb/GaSb superlattices smooth layer.SLs grown on GaAs substrates(GaAs-based SLs) showed well-resolved satellite peaks in XRD.GaSb-based SLs with better structural quality and smoother surface showed strong photoluminescence at 2.55μm with a full width at half maximum(FWHM) of 20 meV,narrower than 31 meV of GaAs-based SLs.Inferior optical absorption of GaAs-based SL was observed in the range of 2-3μm. Photoresponse of GaSb-based SLs showed the cut-off wavelength at 2.6μm.     

Sufficient Conditions of Robust Schur Stability for Uncertain 2-D Polynomials

１　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒｅｅｘｉｓｔｓａｋｉｎｄｏｆ２Ｄｄｉｓｃｒｅｔｅｓｙｓｔｅｍｓｗｉｔｈｕｎｃｅｒｔａｉｎｐａｒａｍｅｔｅｒｓｏｒｓｕｂｊｅｃｔｔｏｒａｎｄｏｍｄｉｓｔｕｒｂａｎｃｅｓ．Ｄｉｆｆｅｒｅｎｔｆｒｏｍｕｎｃｅｒｔａｉｎ１Ｄｐｏｌｙｎｏｍｉａｌｓ，ｔｈｅｐａｒａｍｅｔｅｒｓｐａｃｅｏｆｔｈｅｕｎｃｅｒｔａｉｎ２Ｄｐｏｌｙｎｏｍｉａｌｓｉｓｏｆ（Ｍ＋１）×（Ｎ＋１）ｄｉｍｅｎｓｉｏｎｓａｔｍｏｓｔ．ＴｈｏｕｇｈｓｏｍｅｒｅｓｕｌｔｓａｂｏｕｔｔｈｅｒｏｂｕｓｔＨ…     

Rolling optimization algorithm based on collision window for single machine scheduling problem

1.INTRODUCTION Thesinglemachinenon preemptiveschedulingto minimizetotalcompletiontimewithdynamicjobar rivalsisthebasicprobleminproductionscheduling.Manyworksfocusoneffectiveheuristicmethodsdue toitsstronglyNP hardcharacter.Themostcommon heuristicsareSPT[1](shortestprocessingtime),ECT[2](earliestcompletiontime),delayed SPT[3],PRTF[4](priorityrulefortotalflowtime),APRTF[4],etc.Withoutfullyutilizinganyinforma tionaboutjobswhichwillarriveinthefuture,the abovemyopicmethodsmayresultinpo…     

The ninth-mode sectorial oscillation of acoustically levitated drops

We report on the ninth-mode sectorial oscillation of acoustically levitated drops excited by actively modulating sound pressure. A numerical computation based on the level set method was performed to model drop shape evolution by solving an incompressible two-phase flow problem. The calculated shapes of the oscillating drop are in good agreement with experimental observations. The relationship between the oscillation frequency and parameters describing the flattened drops is studied both experimentally and numerically. The frequency of the ninth-mode sectorial oscillation decreases with increasing equatorial radius and can be well-described by a modified Rayleigh equation.     

Hybrid Method: Review, Modularization and Application

1　IntroductionDuetothehighcostsofsurvey-basedmodelsandtheinherentinaccuracyofnon-surveymodels,hybridmodelsarebeingusedextensivelyinthepracticeofconstructingInput-Output(IO)tables.Thetrendtowardhybridmodelsisnatural.Hybridmodel,orcalledpartial-survey...