We report an all-fiberized 30-W supercontinuum (SC) generation in a piece of ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber. The pump source is thulium-doped fiber amplifier (TDFA) with broadband output spectrum spanning the 1.9 to ∼2.6  μm region. used ZBLAN has core diameter 10 μm, and was directly fusion-spliced pigtail TDFA without using traditional mode field adapter (MFA) or transition Such low-loss robust fusion splice joint, together AlF3-fiber-based endcap, enables efficient high-power SC An...

The development of a G-band traveling wave tube for wireless communications and airborne radars is described. maximum output power this device over 20 W. This provides saturation 15 W gain 32 dB with bandwidth 7.6 GHz. A folded waveguide circuit modified circular bends utilized to eliminate the band-edge instability caused by high beam voltage kV. pencil 50 mA transmission ratio 95 % realized, making capable operating in continuous mode. Periodic permanent magnets are employed compactness....

This letter presents the research progress of a pulsed G-band 50 W traveling wave tube (TWT) with pencil beam focused by periodic permanent magnet (PPM). Three approaches have been combined to improve tube's operation performances including setting operating point near cutoff frequency, using folded waveguide (FWG) slow structure (SWS) modified circular bends (MCBs), and adopting phase velocity tapering (PVT) technique. The measured output power can be over at 5% duty cycle bandwidth 3.6 GHz...

To achieve coherent power combination of Ka-band high-power microwave (HPM), a phase-locked klystron-type coaxial relativistic Cherenkov generator (PKC-RCG), which combines the advantageous characteristics weak dimensional sensitivity RCG and low input ratio triaxial klystron amplifier (TKA), is proposed investigated in this paper. The PKC-RCG composed two parts: pre-modulation region adapted from TKA an energy exchange RCG. used for initial speed modulation intense electron beams (IREB),...

A Ku-band phase-locked coaxial relativistic Cherenkov generator with a low guiding magnetic field is presented. Owing to the use of combined periodic double-corrugation slow-wave structure, quasi-TEM mode exhibits strong axial electric at center beam tunnel. As result, electron can achieve effective beam–wave interaction without proximity SWS surfaces, allowing larger envelope and, therefore, reducing demand for fields. Two single-gap cascaded pre-modulation cavities are used reduce injected...

ABSTRACT We present a high-speed deep learning-based phase retrieval approach for Shack–Hartmann wavefront sensors used in astronomical adaptive optics. It reconstructs the Zernike modal coefficients from image captured by sensor with lightweight convolutional neural network. Compared to traditional slope-based reconstruction, proposed uses directly as inputs more high-order aberrations. recently developed iterative methods, speed is much faster computation time less than 1 ms 100-aperture...

The mode selection of a low guiding magnetic field relativistic Cherenkov generator based on coaxial combined periodic double-corrugation slow-wave structure (CPD-SWS) is studied. Owing to the flexible combination different periods CPD-SWS, electric distribution can be modified and coupling impedance specific enhanced, thus expected selected. research results indicate that quasi-TEM selected by adjusting depth outer inner corrugations CPD-SWS. Moreover, TM01 length corrugation Furthermore,...

The adsorption of isolated ${\mathrm{H}}_{2}\mathrm{O}$ on Pd {100} has been investigated by density functional theory calculations. We have presented a detailed picture for the water monomer various high-symmetry sites surface. demonstrated that other $d$ orbitals are responsible adsorptions, in addition to well-recognized role ${d}_{z}^{2}$ orbital. Furthermore, $\mathrm{Pd}\phantom{\rule{0.2em}{0ex}}5\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ state was found play an essential adsorptions...

A concentric arc meander line (CAML) slow wave structure (SWS) was proposed for applications on low voltage and high efficiency Ka-band traveling tube (TWT). Due to the CAML formed with a series of arcs, electric field in radial direction may be more uniform, which make beam-wave interaction sufficient electron improved. The metal shielding symmetrical ridges employed impedance matching obtain wide bandwidth. Simulated results demonstrate that CAML-SWS TWT has good transmission performance...

An efficient hybrid method based on the time domain integral equation (TDIE) coupled with physical optics (PO) is proposed for transient scattering from electrically large conducting objects. The computational complexity of drastically reduced compared full TDIE, and accuracy improved only PO. numerical results demonstrate validity efficiency method.

This paper derives a multiresolution time-domain (MRTD) scheme for the two-conductor lossless transmission line equations based on Daubechies’ scaling functions. And method is proposed to generate at terminal and near of lines. The stability numerical dispersion this are studied, shows better property than conventional FDTD method. Then MRTD extended lossy equations. implemented with different basis functions both Numerical results show that schemes which use high vanishing moment obtain...

Summary The interaction between animals and plants for seed dispersal predation has received much attention; however, the underlying physiological mechanisms driving responses of both seeds remain unclear. We conducted a series behaviour physiology experiments to examine role plant hormones in regulating germination rodent hoarding Quercus variabilis Leopoldamys edwardsi systems. found that acorns were partially consumed by rodents had increased gibberellin (GA) levels shortened time....

A general dispersion function of the coaxial/cylindrical slow wave structure (SWS) with arbitrary boundary is derived based on operator theory. Owing to introduction operators, proposed theoretical model can be expressed in a simple form, where functions are no longer restricted even functions, and both symmetric asymmetric modes considered. In order verify validity model, coaxial complicated combined periodic SWS (CP-SWS) cylindrical one calculated. Moreover, results compared simulation...

This paper introduces a high-power broadband X-band klystron amplifier that achieves an output power of 157 MW and 3 dB operating bandwidth 6.7%. The employs explosive emission diode with high impedance, which balances the requirements broadband. multi-gap input cavities are designed to operate at two different longitudinal modes within frequency band, resulting in flat absorption rate efficiency. Moreover, eight-stage stagger-tuned bunching section is implemented achieve uniform fundamental...

The adsorption of an H2O molecule on Ni{111} has been investigated by density functional theory (DFT) calculations. In addition to the consensus between previously reported experimental data and our DFT results arrived at via surface relaxation pattern, electron work function energy levels a free H2O, as well energy, we have further presented unrecognized electronic picture for stable on-top adsorption, analysis projected states. We provided clear evidence that Ni 3p orbitals (pz py),...

A concentric arc meander line slow wave structure (CAML-SWS) for low voltage, high efficiency, and wide bandwidth V-band traveling tube (TWT) with dual sheet beam (DSB) is proposed. As a nonperiodic SWS, the CAML-SWS utilized obtaining operational voltage performance. The DSB employed efficiency enhancement. simulated reflection loss (|S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><b>11</b></sub> |) smaller than -30 dB covering whole V-band....

A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -band traveling-wave tube (TWT) with profiled helix pitches and inner diameters of slow wave structure (SWS) is proposed. The transmission characteristics the TWT are simulated by Computer Simulation Technology (CST). In operating frequency band (36.5–41.5 GHz), voltage standing ratio (VSWR) less than 1.5. addition, beam–wave...

Based upon the full-electron ab initio calculations, we found orientational preferences and correlation for atop-to-atop motions of an ${\mathrm{H}}_{2}\mathrm{O}$ on Al{100}, which originates from symmetry match between surface square lattice. We have provided theoretical evidence that favored mechanisms can be classical hopping coupled with either molecular flipping or in-plane reorientations, reduced energy barriers compared to those simple translational motions; while quantum tunneling...

We propose a continuous wave dual-wavelength-pumped scheme for visible supercontinuum (SC) generation. The is numerically studied in this paper. In the scheme, dual-wavelength pump source produced through four-wave mixing process photonic crystal fiber. SC generation investigated by solving generalized nonlinear Schrödinger equation. results verify that can be generated which implies promising generating with high spectral power densities.

We propose an $E$-truncated $K$-moment and semidefinite relaxations (ETKM-SDR) method to check whether $m$-partite quantum mixed state is separable give a decomposition for it if is. first convert the separability discrimination problem of states positive Hermitian tensors. Then, employing method, we obtain optimization model discriminating separability. Moreover, by applying relaxation get hierarchy models algorithm detecting states. The can also be used symmetric nonsymmetric By numerical...

In complicated high dynamic scene, current gamma correction methods sometimes suffer from a loss of local details in certain regions different luminance. this paper, an adaptive method based on mean value adjustment is proposed, which aimed at improve both dark and bright image. As the preprocessing, global enhancement applied to contrast then proposed undertook. Based Shih-Chia Huang's method, has made improvement two aspects it regions. For one thing, average gray regarded as critical...