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<jats:p>Universality of the dynamic characteristic relationship between the characteristic time <jats:italic>t</jats:italic> <jats:sub>c</jats:sub> and the two-electron Coulomb interaction energy <jats:inline-formula> <jats:tex-math> <?CDATA ${\bar{V}}_{12}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mover accent="true"> <mml:mi>V</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mrow> <mml:mn>12</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_11_113201_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> of the ground state in the two-photon double ionization process is investigated via changing the parameters of the two-electron atomic system and the corresponding laser conditions. The numerical results show that the product <jats:inline-formula> <jats:tex-math> <?CDATA ${t}_{{\rm{c}}}{\bar{V}}_{12}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>t</mml:mi> <mml:mi mathvariant="normal">c</mml:mi> </mml:msub> <mml:msub> <mml:mover accent="true"> <mml:mi>V</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mrow> <mml:mn>12</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_11_113201_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> keeps constant around 4.1 in the cases of changing the nucleus charge, the electron charge, the electron mass, and changing simultaneously the nucleus charge and the electron charge. These results demonstrate that the dynamic characteristic relationship in the two-photon double ionization process is universal. This work sheds more light on the dynamic characteristic relationship in ultrafast processes and may find its application in measurements of attosecond pulses.</jats:p>

<jats:p>Employing a silver nano semi-ellipsoid nanoarray with high symmetry into applications in plasmonic color printing, we fulfill printing images with colors independent of observing angles. Also, by decreasing the period of a nano semi-ellipsoid array into deep-subwavelength scales, we obtain high reflectivity over 50%, promising high efficiency for imaging generations. A facile technique based on the transfer of anodized aluminum oxide template is developed to fabricate the silver nano semi-ellipsoid nanoarray, realizing plasmonic color printing with features of low cost, scalable, full color and high flexibility. Our approach provides a feasible way to address the angle-dependent issue in the previous practice of plasmonic color printing, and boosts this field on its way to real-world commercial applications.</jats:p>

<jats:p>We demonstrated the generation and characterization of 9.7 fs, 180 <jats:italic>μ</jats:italic>J pulses centered at 385 nm via the frequency doubling of few-cycle near-infrared pulses. Both moderate conversion efficiency (9.5%) and broad phase matching bandwidth (20 nm) were achieved by shaping the spectra of the fundamental pulses. The strong intensity dependence of second-order harmonic generation and well controlled material dispersion ensured the inexistence of satellite pulses, which was confirmed by the self-diffraction frequency resolved optical gating measurement.</jats:p>

<jats:p>Determination and control of nitrogen-vacancy (NV) centers play an important role in sensing the vector field by using their quantum information. To measure orientation of NV centers in a diamond particle attached to a tapered fiber rapidly, we propose a new method to establish the direction cosine matrix between the lab frame and the NV body frame. In this method, only four groups of the ODMR spectrum peaks shift data need to be collected, and the magnetic field along ± <jats:italic>Z</jats:italic> and ± <jats:italic>Y</jats:italic> in the lab frame is applied in the meantime. We can also control any NV axis to rotate to the <jats:italic>X</jats:italic>, <jats:italic>Y</jats:italic>, <jats:italic>Z</jats:italic> axes in the lab frame according to the elements of this matrix. The demonstration of the DC and microwave magnetic field vector sensing is presented. Finally, the proposed method can help us to perform vector magnetic field sensing more conveniently and rapidly.</jats:p>

<jats:p>Through atomic molecular dynamics simulations, we investigate the performance of two graphenic materials, boron (BC<jats:sub>3</jats:sub>) and nitrogen doped graphene (C<jats:sub>3</jats:sub>N), for seawater desalination and salt rejection, and take pristine graphene as a control. Effects of inter-layer separation have been explored. When water is filtered along the transverse directions of three-layered nanomaterials, the optimal inter-layer separation is 0.7–0.9 nm, which results in high water permeability and salt obstruction capability. The water permeability is considerably higher than porous graphene filter, and is about two orders of magnitude higher than commercial reverse osmosis (RO) membrane. By changing the inter-layer spacing, the water permeability of three graphenic layered nanomaterials follows an order of C<jats:sub>3</jats:sub>N ≥ GRA &gt; BC<jats:sub>3</jats:sub> under the same working conditions. Amongst three nanomaterials, BC<jats:sub>3</jats:sub> is more sensitive to inter-layer separation which offers a possibility to control the water desalination speed by mechanically changing the membrane thickness. This is caused by the intrinsic charge transfer inside BC<jats:sub>3</jats:sub> that results in periodic distributed water clusters around the layer surface. Our present results reveal the high potentiality of multi-layered graphenic materials for controlled water desalination. It is hopeful that the present work can guide design and fabrication of highly efficient and tunable desalination architectures.</jats:p>

<jats:p>The isothermal compression dynamics of ternary Ti-6Al-4V alloy with initial martensitic structures were investigated in the high temperature range 1083–1173 K and moderate strain rate regime 0.01–10 s<jats:sup>−1</jats:sup>. Shear banding was found to still dominate the deformation mechanism of this process, despite its nonadiabatic feature. The constitutive equation was derived with the aid of Zener–Hollomon parameter, which predicted the apparent activation energy as 534.39 kJ/mol. A combination of higher deformation temperature and lower strain rate suppressed the peak flow stress and promoted the evolution of shear bands. Both experiments and calculations demonstrated that a conspicuous temperature rise up to 83K could be induced by severe plastic deformation. This facilitated the dynamic recrystallization of deformed martensites, as evidenced by the measured microhardness profiles across shear bands.</jats:p>

<jats:p>We investigate the Rashba and Dressehaus spin–orbit (SO) couplings in an ordinary GaAs/AlGaAs asymmetric double well, which favors the electron occupancy of three subbands <jats:italic>ν</jats:italic> = 1, 2, 3. Resorting to an external gate, which adjusts the electron occupancy and the well symmetry, we demonstrate distinct three-level SO control of both Rashba (<jats:italic>α<jats:sub>ν</jats:sub> </jats:italic>) and Dresselhaus (<jats:italic>β<jats:sub>ν</jats:sub> </jats:italic>) intraband terms. Remarkably, as the gate varies, the first-subband SO parameters <jats:italic>α</jats:italic> <jats:sub>1</jats:sub> and <jats:italic>β</jats:italic> <jats:sub>1</jats:sub> comply with the usual linear behavior, while <jats:italic>α</jats:italic> <jats:sub>2</jats:sub> (<jats:italic>β</jats:italic> <jats:sub>2</jats:sub>) and <jats:italic>α</jats:italic> <jats:sub>3</jats:sub> (<jats:italic>β</jats:italic> <jats:sub>3</jats:sub>) respectively for the second and third subbands interchange the values, triggered by a gate controlled <jats:italic>band swapping</jats:italic>. This provides a pathway towards fascinating selective SO control in spintronic applications. Moreover, we observe that the interband Rashba (<jats:italic>η<jats:sub>μν</jats:sub> </jats:italic>) and Dresselhaus (<jats:italic>Γ<jats:sub>μν</jats:sub> </jats:italic>) terms also exhibit contrasting gate dependence. Our results should stimulate experiments probing SO couplings in multi-subband wells and adopting relevant SO features in future spintronic devices.</jats:p>

<jats:p>We study theoretically the exciton Bose–Einstein condensation and exciton vortices in a two-dimensional (2D) perovskite (PEA)<jats:sub>2</jats:sub>PbI<jats:sub>4</jats:sub> monolayer. Combining the first-principles calculations and the Keldysh model, the exciton binding energy of in a (PEA)<jats:sub>2</jats:sub>PbI<jats:sub>4</jats:sub> monolayer can approach hundreds of meV, which make it possible to observe the excitonic effect at room temperature. Due to the large exciton binding energy, and hence the high density of excitons, we find that the critical temperature of the exciton condensation could approach the liquid nitrogen regime. In the presence of perpendicular electric fields, the dipole-dipole interaction between excitons is found to drive the condensed excitons confined in (PEA)<jats:sub>2</jats:sub>PbI<jats:sub>4</jats:sub> monolayer flakes into patterned vortices, as the evolution time of vortex patterns is comparable to the exciton lifetime.</jats:p>

<jats:p>We report an exact numerical study on disorder effect in double-Weyl semimetals, and compare exact numerical solutions for the quasiparticle behavior with the Born approximation and renormalization group results. It is revealed that the low-energy quasiparticle properties are renormalized by multiple-impurity scattering processes, leading to apparent power-law behavior of the self-energy. Therefore, the quasiparticle residue surrounding nodal points is considerably reduced and vanishes as <jats:italic>Z</jats:italic> <jats:sub>E</jats:sub> ∞ <jats:italic>E<jats:sup>r</jats:sup> </jats:italic> with nonuniversal exponent <jats:italic>r</jats:italic>. We show that such unusual behavior of the quasiparticle leads to strong temperature dependence of diffusive conductivity. Remarkably, we also find a universal minimum conductivity along the direction of linear dispersion at the nodal point, which can be directly observed by experimentalist.</jats:p>

<jats:p>We carry out <jats:italic>ab initio</jats:italic> density functional theory calculations to study manipulation of electronic structures of self-assembled molecular nanostructures on metal surfaces by investigating the geometric and electronic properties of glycine molecules on Cu(100). It is shown that a glycine monolayer on Cu(100) forms a two-dimensional hydrogen-bonding network between the carboxyl and amino groups of glycine using a first principles atomistic calculation on the basis of a recently found structure. This network includes at least two hydrogen-bonding chains oriented roughly perpendicular to each other. Through molecule–metal electronic hybridization, these two chains selectively hybridized with the two isotropic degenerate Cu(100) surface states, leading to two anisotropic quasi-one-dimensional surface states. Electrons occupying these two states can near-freely move from a molecule to its adjacent molecules directly through the intermolecular hydrogen bonds, rather than mediated by the substrate. This results in the experimentally observed anisotropic free-electron-like behavior. Our results suggest that hydrogen-bonding chains are likely candidates for charge conductors.</jats:p>