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<jats:p>We study the dissipative quantum phase transition (QPT) in a biased Tavis–Cummings model consisting of an ensemble of two-level systems (TLSs) interacting with a cavity mode, where the TLSs are pumped by a drive field. In our proposal, we use a dissipative TLS ensemble and an active cavity with effective gain. In the weak drive-field limit, the QPT can occur under the combined actions of the loss and gain of the system. Owing to the active cavity, the QPT behavior can be much differentiated even for a finite strength of the drive field on the TLS ensemble. Also, we propose to implement our scheme based on the dissipative nitrogen-vacancy (NV) centers coupled to an active optical cavity made from the gain-medium-doped silica. Furthermore, we show that the QPT can be measured by probing the transmission spectrum of the cavity embedding the ensemble of the NV centers.</jats:p>

<jats:p>In order to further study the dynamical behavior of nonconservative systems, we study the conserved quantities and the adiabatic invariants of fractional Brikhoffian systems with four kinds of different fractional derivatives based on Herglotz differential variational principle. Firstly, the conserved quantities of Herglotz type for the fractional Brikhoffian systems based on Riemann–Liouville derivatives and their existence conditions are established by using the fractional Pfaff–Birkhoff–d′Alembert principle of Herglotz type. Secondly, the effects of small perturbations on fractional Birkhoffian systems are studied, the conditions for the existence of adiabatic invariants for the Birkhoffian systems of Herglotz type based on Riemann–Liouville derivatives are established, and the adiabatic invariants of Herglotz type are obtained. Thirdly, the conserved quantities and adiabatic invariants for the fractional Birkhoffian systems of Herglotz type under other three kinds of fractional derivatives are established, namely Caputo derivative, Riesz–Riemann–Liouville derivative and Riesz–Caputo derivative. Finally, an example is given to illustrate the application of the results.</jats:p>

<jats:p>We experimentally investigate the effect of the hopper angle on the flow rate of grains discharged from a two-dimensional horizontal hopper on a conveyor belt. The flow rate grows with the hopper angle, and finally reaches a plateau. The curve feature appears to be similar for different orifice widths and conveyor belt-driven velocities. On the basis of an empirical law of flow rate for a flat-bottom hopper, we propose a modified equation to describe the relation between the flow rate and hopper angle, which is in a good agreement with the experimental results.</jats:p>

<jats:p>The processes of electric ion extraction from plasma induced by pulse lasers are simulated by particle-in-cell (PIC) method and hybrid-PIC method. A new calculation scheme named preprocessing hybrid-PIC is presented because neither of the two methods above is omnipotent, especially under the circumstance of high initial plasma density. The new scheme provides credible results with less computational consumption than PIC method in both one- and two-dimensional simulations, except for Π-type electrode configuration. The simulation results show that the M-type performs best in all electrode configurations in both high-density and low-density plasma conditions.</jats:p>

<jats:p>The optical properties of cylindrical core–shell nanorods (CCSNs) are theoretically investigated in this paper. The results show that Fano resonance can be generated in CCSNs, and the wavelength and the intensity at Fano dip can be tuned respectively by adjusting the field coupling of cavity mode inside and near field on gold surface. The high tuning sensitivity which is about 400 nm per refractive-index unit can be obtained, and an easy-to-realize tunable parameter is also proposed. A two-oscillator model is also introduced to describe the generation of Fano resonance in CCSNs, and the results from this model are in good agreement with theoretical results. The CCSNs investigated in this work may have promising applications in optical devices.</jats:p>

<jats:p>Herein we report a prototypical electronic substrate specifically designed to serve the weakly interacting massive particles (WIMPs) detectors at the China Dark Matter Experiment (CDEX). Because the bulky high-purity germanium (HPGe) detectors operate under liquid-nitrogen temperatures and ultralow radiation backgrounds, the desired electronic substrates must maintain high adhesivity across different layers in such cold environment and be free from any radioactive nuclides. To conquer these challenges, for the first time, we employed polytetrafluoroethylene ((C<jats:sub>2</jats:sub>F<jats:sub>4</jats:sub>)<jats:sub> <jats:italic>n</jats:italic> </jats:sub>) foil as the base substrate, in conjunction with ion implantation and deposition techniques using an independently developed device at Beijing Normal University for surface modification prior to electroplating. The remarkable peeling strengths of 0.88±0.06 N/mm for as-prepared sample and 0.75±0.05 N/mm for that after 2.5-days of soaking inside the liquid nitrogen were observed, while the regular standards commonly require 0.4 N/mm ∼ 0.6 N/mm for electronic substrates.</jats:p>

<jats:p>Tungsten–potassium (WK) alloy with ultrafine/fine grains and nano-K bubbles is fabricated through spark plasma sintering (SPS) and rolling process. In this study, 3-MeV W<jats:sup>2+</jats:sup> ion irradiation with a tandem accelerator is adopted to simulate the displacement damage caused by neutrons. As the depth of irradiation damage layer is limited to only 500 nm, the hardening behaviors of WK alloy and ITER (International Thermonuclear Experimental Reactor)-W under several damage levels are investigated through Bercovich tip nanoindentation test and other morphological characterizations. The indenter size effect (ISE), soft substrate effect (SSE), and damage gradient effect (DGE) are found to influence the measurement of nano-hardness. Few or no pop-ins in irradiated samples are observed while visible pop-in events take place in unirradiated metals. Extensive pile-up with different morphology features around the indentation exists in both WK and ITER-W. The WK shows a smaller hardness increment than ITER-W under the same condition of displacement damage. This study provides beneficial information for WK alloy serving as a promising plasma facing materials (PFMs) candidate.</jats:p>

<jats:p>We fabricate Sm-doped Ca<jats:sub>3</jats:sub>Co<jats:sub>4</jats:sub>O<jats:sub>9+<jats:italic>δ</jats:italic> </jats:sub> (CCO) bulk materials in magnetic field during both processes of chemical synthesis and cold pressing. The structure and electrical performance of the samples are investigated. With the increasing Sm concentration, the electrical conductivity 1/<jats:italic>ρ</jats:italic> decreases and the Seebeck coefficient <jats:italic>α</jats:italic> increases. As a result, the power factor (PF = <jats:italic>α</jats:italic> <jats:sup>2</jats:sup>/<jats:italic>ρ</jats:italic>) is raised slightly. After applying magnetic field, the extent of texture, grain size and density of all the bulk materials are improved obviously, thereby an enhanced electrical conductivity can be gained. Additionally, the degeneracy of Co<jats:sup>4+</jats:sup> state in the CoO<jats:sub>2</jats:sub> layer of CCO is also increased as the magnetic field is used in the preparing process, which results in an enhanced <jats:italic>α</jats:italic>. The Ca<jats:sub>2.85</jats:sub>Sm<jats:sub>0.15</jats:sub>Co<jats:sub>4</jats:sub>O<jats:sub>9+<jats:italic>δ</jats:italic> </jats:sub> prepared in magnetic field shows the largest power factor (0.20 mW⋅m<jats:sup>−1</jats:sup>⋅K<jats:sup>−2</jats:sup> at 1073 K).</jats:p>

<jats:p>Using molecular dynamics simulations, the plastic deformation behavior of nanocrytalline Ti has been investigated under tension and compression normal to the {0001}, <jats:inline-formula> <jats:tex-math><?CDATA $\{\bar{1}010\}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>{</mml:mo> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>010</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math><?CDATA $\{\bar{1}2\bar{1}0\}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mo>{</mml:mo> <mml:mrow> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>2</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:mrow> <mml:mo>}</mml:mo> </mml:mrow> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> planes. The results indicate that the plastic deformation strongly depends on crystal orientation and loading directions. Under tension normal to basal plane, the deformation mechanism is mainly the grain reorientation and the subsequent deformation twinning. Under compression, the transformation of hexagonal-close packed (HCP)-Ti to face-centered cubic (FCC)-Ti dominates the deformation. When loading is normal to the prismatic planes (both <jats:inline-formula> <jats:tex-math><?CDATA $\{\bar{1}010\}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>{</mml:mo> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>010</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $\{\bar{1}2\bar{1}0\}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>{</mml:mo> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>2</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>), the deformation mechanism is primarily the phase transformation among HCP, body-centered cubic (BCC), and FCC structures, regardless of loading mode. The orientation relations (OR) of {0001}<jats:sub>HCP</jats:sub>║{111}<jats:sub>FCC</jats:sub> and <jats:inline-formula> <jats:tex-math><?CDATA ${\langle \bar{1}210\rangle }_{{\rm{HCP}}}||{\langle 110\rangle }_{{\rm{FCC}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo stretchy="false">〈</mml:mo> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>210</mml:mn> <mml:mo stretchy="false">〉</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">HCP</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> <mml:msub> <mml:mrow> <mml:mo stretchy="false">〈</mml:mo> <mml:mn>110</mml:mn> <mml:mo stretchy="false">〉</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">FCC</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn5.gif" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math><?CDATA ${\{10\bar{1}0\}}_{{\rm{HCP}}}||{\{1\bar{1}0\}}_{{\rm{FCC}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo>{</mml:mo> <mml:mn>10</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">HCP</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> <mml:msub> <mml:mrow> <mml:mo>{</mml:mo> <mml:mn>1</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">FCC</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA ${\langle 0001\rangle }_{{\rm{HCP}}}||{\langle 010\rangle }_{{\rm{FCC}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mo stretchy="false">〈</mml:mo> <mml:mn>0001</mml:mn> <mml:mo stretchy="false">〉</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">HCP</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> <mml:msub> <mml:mrow> <mml:mo stretchy="false">〈</mml:mo> <mml:mn>010</mml:mn> <mml:mo stretchy="false">〉</mml:mo> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">FCC</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn7.gif" xlink:type="simple" /> </jats:inline-formula> between the HCP and FCC phases have been observed in the present work. For the transformation of HCP → BCC → HCP, the OR is <jats:inline-formula> <jats:tex-math><?CDATA ${0001}_{\alpha 1}||{\{110\}}_{\beta }||{\{10\bar{1}0\}}_{\alpha 2}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mn>0001</mml:mn> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> <mml:msub> <mml:mrow> <mml:mo>{</mml:mo> <mml:mn>110</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> <mml:mi>β</mml:mi> </mml:msub> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> <mml:msub> <mml:mrow> <mml:mo>{</mml:mo> <mml:mn>10</mml:mn> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> <mml:mo>}</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_29_4_046201_ieqn8.gif" xlink:type="simple" /> </jats:inline-formula> (HCP phase before the critical strain is defined as <jats:italic>α</jats:italic> <jats:sub>1</jats:sub>-Ti, BCC phase is defined as <jats:italic>β</jats:italic>-Ti, and the HCP phase after the critical strain is defined as <jats:italic>α</jats:italic> <jats:sub>2</jats:sub>-Ti). Energy evolution during the various loading processes further shows the plastic anisotropy of nanocrystalline Ti is determined by the stacking order of the atoms. The results in the present work will promote the in-depth study of the plastic deformation mechanism of HCP materials.</jats:p>

<jats:p>Heusler Co<jats:sub>2</jats:sub>FeSi films with a uniaxial magnetic anisotropy and high ferromagnetic resonance frequency <jats:italic>f</jats:italic> <jats:sub>r</jats:sub> were deposited by an oblique sputtering technique on Ru underlayers with various thicknesses <jats:italic>t</jats:italic> <jats:sub>Ru</jats:sub> from 0 nm to 5 nm. It is revealed that the Ru underlayers reduce the grain size of Co<jats:sub>2</jats:sub>FeSi, dramatically enhance the magnetic anisotropy field <jats:italic>H</jats:italic> <jats:sub>K</jats:sub> induced by the internal stress from 242 Oe (1 Oe = 79.5775 A⋅m<jats:sup>−1</jats:sup>) to 582 Oe with an increment ratio of 2.4, while a low damping coefficient remains. The result of damping implies that the continuous interface between Ru and Co<jats:sub>2</jats:sub>FeSi induces a large in-plane anisotropic field without introducing additional external damping. As a result, excellent high-frequency soft magnetic properties with <jats:italic>f</jats:italic> <jats:sub>r</jats:sub> up to 6.69 GHz are achieved.</jats:p>