We demonstrate stable 70 ns pulse generation from a Yb-doped fiber laser passively Q-switched by graphene-based saturable absorber mirror in short linear cavity. The maximum output power was 12 mW and the highest single energy 46 nJ. repetition rate of can be widely tuned 140 to 257 kHz along with increase pump power. To best our knowledge, this is first report for sub-100-ns operation laser.

A high-power single-frequency, single-polarization, thulium-doped all-fiber master-oscillator power-amplifier (MOPA) is demonstrated by using all-polarization-maintaining (all-PM) fiber and all-PM-fiber components. The MOPA yielded 210 W of linear-polarized laser output at central wavelength 2000.9 nm with a polarization extinction ratio (PER) >17 dB. No indication stimulated Brillouin scattering (SBS) could be observed the highest power level, was only currently limited available pump...

To address the issue of low-frequency micro-vibrations affecting performance large precision instruments, this paper proposes a hybrid active-passive vibration isolation system. While air springs are widely elected as excellent passive elements, their nonlinear characteristics and resonance limit effectiveness in isolating vibrations. enhance performance, piezoelectric actuators serially connected to springs. Theoretical modeling spring stiffness natural frequency is conducted, followed by...

It is shown that wave-function renormalization can introduce an important contribution to the generation of baryon and lepton number asymmetries by heavy particle decay. These terms, omitted in previous analyses, are same order magnitude as standard terms.

We report a stable highly-integrated high power picosecond thulium-doped all-fiber MOPA system without using conventional chirped pulse amplification technique. The master oscillator was passively mode-locked by SESAM to generate average of 15 mW at fundamental repetition rate 103 MHz in short linear cavity, and uniform narrow bandwidth FBG is employed stabilize the laser operation. Two-stage double-clad amplifiers were used directly boost 20.7 W. center wavelength 1962.8 nm width 18 ps....

Different pulse-shaping mechanisms were investigated experimentally and numerically in passively mode-locked thulium-doped fiber lasers. Conventional solitons demonstrated a semiconductor saturable absorber mirror anomalous dispersion laser. With normal spectral filter added cavity, processes theoretically analyzed the presence of map dissipation The existence parabolic pulse as nonlinear attraction was proved distinct intensity profiles evolution from Gaussian shape to proposed dissipative...

In this paper, an electromagnetic energy‐regenerative suspension system is proposed to achieve active control and vibration energy harvesting. For system, a PID controller based on BP neural network algorithm designed vehicle dynamic performances are studied. Based the traditional efficiency calculation, novel self‐supply concept evaluate utilization effect of recycled for dual‐functional suspension. Simulations carried out, results show that effectively improved under different input...

Concrete-filled steel tubes (CFSTs) have been used extensively as main members with different inclinations in bridge structures; however, investigations on the influence of member inclination temperature gradient are inadequate. To fill this gap, long-term measurements were made structural three CFST 0°, 45°, and 90°, along simultaneous meteorological parameters, including solar radiation, air temperature, wind speed. It was found that distinctions do indeed exist sun-side differences...

At present, the global pollution has seriously exceeded standard. With passage of time, gradually affected people's daily lives, but solution to is far from achieving a better treatment effect. For pollution, in addition considering effect, it also necessary consider whether method will cause and cost pollutants. As one lifelines human survival, land suffering pollution. The impact heavy metal particularly serious, there no solution. Based on this, this paper proposes curing agent based...

This study focuses on investigating the flow and heat transfer characteristics of Copper-water nanofluids (Cu-H2O) water in microchannels with varying curvatures. The results reveal that Cu-H2O demonstrate superior performance compared to pure all four microchannels. Moreover, curved exhibit higher than straight microchannels, regardless whether is laminar or turbulent. improves increasing channel curvature, volume fraction nanoparticles, decreasing particle size. During flow, impact...

An explicit calculation for the decay $b\ensuremath{\rightarrow}s\ensuremath{\gamma}\ensuremath{\gamma}$ is carried out in standard electroweak model. We find that terms with lowest powers of external momenta are only proportional to dipole moment form factor responsible $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$. It shown this result can be regarded as a non-soft-bremsstrahlung extension Low's low-energy theorem. Without QCD corrections, branching ratio...

Vehicle interior noise is an important factor affecting ride comfort. To reduce the inside vehicle at body design stage, a finite element model of must be established. While taking first-order global modal body-in-white, maximum sound pressure level target point in vehicle, mass, and side impact conditions into account, thickness panel as determined via sensitivity analysis treated input variable, sample by following Hamersley experimental design. Specifically, Elman neural network predicts...

We discuss a class of flavor-changing two-photon rare decays, such as b\ensuremath{\rightarrow}s\ensuremath{\gamma}\ensuremath{\gamma}. Both dimension-six and dimension-eight operators are shown to contribute these decays. For heavy top, contributions from become sizable even dominant. They can be simply related single-photon decay like b\ensuremath{\rightarrow}s\ensuremath{\gamma}. Implications for ${\mathit{B}}_{\mathit{s}}$\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}...

Commutation torque ripple is an important factor affecting the performance of brushless DC (BLDC) motor drives. In order to suppress this ripple, alternating conduction control strategy between two-phase and three-phase mode has been proposed in study. During non-commutation periods, conventional selected drive BLDC motor. While during commutation period, reduced by employing mode. By calculating duty cycle mode, which indicates whether rate change current incoming outgoing phase equal...

In this paper, the least squares method is used to determine vertical height of road space domain. Based on estimation method, active suspension control mode switching model constructed, and dynamic characteristics vehicle in comfort, safety, integrated modes are analyzed. The vibration signal collected by sensor, parameters such as driving conditions solved for reverse. A strategy multiple under different surfaces speeds constructed. At same time, particle swarm optimization algorithm (PSO)...

In this paper, we investigate the integrability and equivalence relationships of six coupled Korteweg–de Vries equations. It is shown that equations are identical under certain invertible transformations. We reconsider matrix representations prolongation algebra for Painlevé integrable equation in [Appl. Math. Lett. 23 (2010) 665‐669] propose a new Lax pair can be used to construct exact solutions with vanishing boundary conditions. also pointed out all have fourth‐order pairs instead...

A novel electromagnetic active suspension with an energy-regenerative structure is proposed to solve the suspension’s control consumption problem. For this new system, a 2-DOF quarter-car model built, and dynamics performances are studied using variable universe fuzzy theory PD approach. self-powered efficiency concept defined describe regenerative structure’s contribution whole consumption, its influent factors also discussed. Simulations carried out software Matlab/Simulink, experiments...

For the serrated heat transfer surface, and flow properties are investigated with external vibration excitation using numerical simulation method. By dynamic grid to realize of fin wall, impacts frequency, amplitude, wind velocity ambient temperature on vibration-strengthened investigated. The results show that distribution around fin, interferes air, causes air form a certain angle thus preventing development boundary layer achieving strengthened transfer. impact amplitude is smaller than...

We study one-loop radiative corrections to the top-quark decay: t→bW. For a heavy top (i.e. m t ≳100 GeV ), simple analytic formulas are derived. inclusive process, t→bW+X due QCD, cancellations of infrared and mass singularities shown explicitly. The final result agrees with an earlier calculation in literature, is 8% reduction partial width for α s =0.1. Also, leading terms electroweak be proportional enhancement factor [Formula: see text]. Their effect about 1-3%. also angular...