Prediction of Grinding Force by an Electroplated Grinding Wheel with Orderly-Micro-Grooves

The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process.This paper aimed to establish a single-grit cutting force model to predict the ploughing,friction and cutting forces in a grinding process.It took into the consideration of actual topography of the grinding wheel,and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed.The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression,and it reflected the microstructure characteristics of the structured wheel explicitly.Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel.The proposed force prediction model was validated by surface grinding experiments,and the results showed(1)a good agreement of the predicted and measured forces and(2)a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments.This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate,reliable and effective in predicting grinding forces.

Trajectory analysis of few-cycle strong field ionization in two-color circularly polarized fields

Bichromatic circularly polarized fields provide a useful tool to probe the ionization dynamics.In this work, we compare the photoelectron momentum distribution in few-cycle bichromatic field of different helicities.The spectral features are analyzed with semiclassical trajectories derived from the strong field approximation.In particular, the interference fringes in momentum distribution are investigated by tracking the ionization time and tunneling exits of released photoelectrons.Different types of trajectories that contribute to the interference fringes are elucidated.

Momentum Spectroscopy for Multiple Ionization of Cold Rubidium in the Elliptically Polarized Laser Field

Employing recently developed magneto-optical trap recoil ion momentum spectroscopy(MOTRIMS)combined with cold atoms,strong laser pulse,and ultrafast technologies,we study momentum distributions of the multiply ionized cold rubidium(Rb)induced by the elliptically polarized laser pulses(35 fs,1.3×10^15 W/cm^2).The complete vector momenta of Rb^n+ions up to charge state n=4 are recorded with extremely high resolution(0.12 a.u.for Rb^+).Variations of characteristic multi-bands are displayed in momentum distributions because the ellipticity varies from the linear to circular polarization,are interpreted qualitatively with the classical overbarrier ionization model.Present momentum spectroscopy of cold heavy alkali atoms presents novel strong-field phenomena beyond the noble gases.

Continuum electron giving birth to terahertz emission

The origin of terahertz(THz)generation in a gas-phase medium is still in controversy,although the THz sources have been applied across many disciplines.Herein,the THz generation in a dual color field is investigated experimentally by precisely controlling the relative phase and polarization of dual-color lasers,where the accompanying third-harmonic generation is employed for in situ determination of the relative phase up to sub-wavelength accuracy.Joint studies with the strong approximation(SFA)theory reveal that the continuum-continuum(CC)transition within an escaped electron wave packet in the single atom gives birth to THz emission,without the necessity of considering the plasma effect.Meanwhile,we develop the analytic form from SFA-based CC description,which is able to reproduce and decompose the classical photocurrent model from the viewpoint of microscopic quantum theory,establishing the quantum-lassical correspondence and bringing a novel insight into the mechanism of THz generation.Present studies leave open the possibility for probing the ultrafast dynamics of continuum electrons and a new dimension for the study of THz-related science and methodology.

Phosphoregulation of the dimerization and functions of end-binding protein 1

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Industry effect of job hopping: an agent-based simulation of Chinese construction workers

Job hopping affects the development of industries in terms of efficiency and quality of work. It is a problem for the Chinese construction industry, where excessive job hopping is detrimental to meeting the current daunting challenges involved in the industry's transformation and efficiency improvement. To provide an exhaustive analysis of this effect, game theory is combined with social relationship networks to create an agent-based simulation model. Simulation results indicate that the frequent job moves of Chinese construction workers have a negative effect on their skill development, employment, and worker relationships, as well as results in sharp increase in employer labor costs. The findings point to the need to act for the benefit of workers and employers and maintain the development of the industry.