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<jats:p>A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) is studied, which is based on a look-up table algorithm. The algorithm uses parametric method to represent aerosol extinction profiles and simulate different atmospheric aerosol states through atmospheric radiation transfer model. Based on the method, aerosol extinction profile was obtained during six cloud-free days. The O<jats:sub>4</jats:sub> differential air mass factor (dAMF) measured by MAX-DOAS is compared with the corresponding model results under different atmospheric conditions (<jats:inline-formula> <jats:tex-math> <?CDATA ${R}^{2}=0.78$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0.78</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_8_084212_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>). The aerosol optical thickness, aerosol weight factor in boundary layer, and the height of the boundary layer are obtained after the process of minimization and look-up table method. The retrieved aerosol extinction in boundary layer is compared with PM2.5 data measured by ground point instrument. The diurnal variation trends of the two methods are in good agreement. The correlation coefficients of the two methods are 0.71 when the aerosol optical thickness is smaller than 0.5. The results show that the look-up table method can obtain the aerosol state of the troposphere and provide validation for other instrument data.</jats:p>

<jats:p>We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field, and found it to be markedly different from that of the Stokes drag. The drag coefficient, along with the measured electrical force, yield a mobility-zeta potential relation that agrees with the literature. By using the measured mobility as input, numerical calculations based on the Poisson–Nernst–Planck equations, coupled to the Navier–Stokes equation, reveal an intriguing microscopic electroosmotic flow near the particle surface, with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer’s outer boundary. This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge. The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem, and can shed light on new applications of electrophoresis to investigate biological nanoparticles.</jats:p>

<jats:p>Manipulating biomacromolecules and micro-devices with light is highly appealing. Opto driving torque can propel micro-rotors to translational motion in viscous liquid, and then separate microsystems according to their handedness. We study the torque of dielectric loss generated by circular polarized lasers. The unwanted axial force which causes the handedness independent translational motion is cancelled by the counter propagating reflection beams. The propelling efficiency and the friction torque of water are obtained by solving the Navier-Stokes equation. In the interesting range of parameters, the numerical friction torque is found to be linear to the angular velocity with a slope depending on the radius of rotor as <jats:italic>r</jats:italic> <jats:sup>3</jats:sup>. The time-dependent distribution of angular velocity is obtained as a solution of the Fokker–Planck equation, with which the thermal fluctuation is accounted. The results shed light on the micro-torque measurement and suggest a controllable micro-carrier.</jats:p>

<jats:p>A novel transit-time oscillator (TTO) is proposed in this paper. An axial cathode which has been widely used in high power microwave (HPM) source and an extractor with radial feature are adopted. In this way, the inherent advantages of axial and radial TTO, both of which can be utilized as high-quality intense relativistic electron beam (IREB), can be generated and the power capacity is also increased. The working mode is <jats:italic>π</jats:italic>/2 mode of TM<jats:sub>01</jats:sub> based on small-signal theory, and under the same energy storage, the maximum electric field in extractor decreases 16.3%. Besides, by utilizing the natural bending of the solenoid, this TTO saves over 60% of the length required by the uniform magnetic field, and consequently reduces the energy consumed by solenoid. The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid, 3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input, and the overall conversion efficiency is 41%.</jats:p>

<jats:p>The damage to the rear surface of fused silica under the action of high power laser is more severe than that incurred by the front surface, which hinders the improvement in the energy of the high power laser device. For optical components, the ionization breakdown by laser is a main factor causing damage, particularly with laser plasma shock waves, which can cause large-scale fracture damage in fused silica. In this study, the damage morphology is experimentally investigated, and the characteristics of the damage point are obtained. In the theoretical study, the coupling and transmission of the shock wave in glass are investigated based on the finite element method. Thus, both the magnitude and the orientation of stress are obtained. The damage mechanism of the glass can be explained based on the fracture characteristics of glass under different stresses and also on the variation of the damage zone’s Raman spectrum. In addition, the influence of the glass thickness on the damage morphology is investigated. The results obtained in this study can be used as a reference in understanding the characteristics and mechanism of damage characteristics induced by laser plasma shock waves.</jats:p>

<jats:p>Migration of He atoms and growth of He bubbles in high angle twist grain boundaries (HAGBs) in tungsten (W) are investigated by atomic simulation method. The energy and free volume (FV) of grain boundary (GB) are affected by the density and structure of dislocation patterns in GB. The migration energy of the He atom between the neighboring trapping sites depends on free volume along the migration path at grain boundary. The region of grain boundary around the He bubble forms an ordered crystal structure when He bubble grows at certain grain boundaries. The He atoms aggregate on the grain boundary plane to form a plate-shape configuration. Furthermore, high grain boundary energy (GBE) results in a large volume of He bubble. Thus, the nucleation and growth of He bubbles in twist grain boundaries depend on the energy of grain boundary, the dislocation patterns and the free volume related migration path on the grain boundary plane.</jats:p>

<jats:p>ErGa<jats:sub>3−<jats:italic>x</jats:italic> </jats:sub>Mn<jats:sub> <jats:italic>x</jats:italic> </jats:sub> disordered alloy is successfully prepared by the vacuum arc melting technology, and the crystal structure and magnetic properties are investigated by using the x-ray diffraction and magnetic measurements. The Rietveld structural analysis indicates that the ErGa<jats:sub>3−<jats:italic>x</jats:italic> </jats:sub>Mn<jats:sub> <jats:italic>x</jats:italic> </jats:sub> crystallizes into a cubic structure with space group of <jats:inline-formula> <jats:tex-math><?CDATA ${Pm}\bar{3}m$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic">Pm</mml:mi> <mml:mover accent="true"> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> <mml:mi>m</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_8_086101_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> in Mn doping range of <jats:italic>x</jats:italic> = 0–0.1. However, the disordered alloy with structural formula of <jats:inline-formula> <jats:tex-math><?CDATA ${\mathrm{Er}}_{0.8}{\mathrm{Ga}}_{2}^{{\rm{I}}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>Er</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0.8</mml:mn> </mml:mrow> </mml:msub> <mml:msubsup> <mml:mrow> <mml:mi>Ga</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">I</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_8_086101_ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>(Ga<jats:sup>II</jats:sup>, Mn)<jats:sub>0.4</jats:sub> as the second phase is separated from cubic phase for the samples with <jats:italic>x</jats:italic> = 0.2 and 0.3, which is induced by substituting the (Ga<jats:sup>II</jats:sup>, Mn)–(Ga<jats:sup>II</jats:sup>, Mn) pair at 2<jats:italic>e</jats:italic> crystal position for the rare earth Er at 1<jats:italic>a</jats:italic> site. The lattice parameters tend to increase with Mn content increasing due to the size effect at Ga (1.30 Å) site by substituting Mn (1.40 Å) for Ga. The paramagnetic characteristic is observed by doping Mn into ErGa<jats:sub>3</jats:sub> at room temperature. With Mn content increasing from <jats:italic>x</jats:italic> = 0 to 0.1, the magnetic susceptibility <jats:italic>χ</jats:italic> tends to increase. This phenomenon can be due to the increase of effective potential induced by doping Mn into ErGa<jats:sub>3</jats:sub>. However, the magnetic susceptibility <jats:italic>χ</jats:italic> continues to decrease with the increase of Mn content in a range of <jats:inline-formula> <jats:tex-math><?CDATA $x\gt 0.2$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>x</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>0.2</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_8_086101_ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>, which is due to the phase separation from the cubic Er(Ga, Mn)<jats:sub>3</jats:sub> to the hexagonal Er<jats:sub>0.8</jats:sub>Ga<jats:sub>2</jats:sub>(Ga, Mn)<jats:sub>0.4</jats:sub>.</jats:p>

<jats:p>Inorganic lead halide perovskite nanocrystals (NCs) with superior photoelectric properties are expected to have excellent performance in many fields. However, the anion exchange changes their features and is unfavorable for their applications in many fields. Hence, impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs. Herein, CsPb<jats:italic>X</jats:italic> <jats:sub>3</jats:sub> (<jats:italic>X</jats:italic> = Cl, Br) NCs are coated with Cs<jats:sub>4</jats:sub>Pb<jats:italic>X</jats:italic> <jats:sub>6</jats:sub> shell to impede anion exchange and reduce anion mobility. The Cs<jats:sub>4</jats:sub>Pb<jats:italic>X</jats:italic> <jats:sub>6</jats:sub> shell is facily fabricated on CsPb<jats:italic>X</jats:italic> <jats:sub>3</jats:sub> NCs through high temperature injection method. Anion exchange experiments demonstrate that the Cs<jats:sub>4</jats:sub>Pb<jats:italic>X</jats:italic> <jats:sub>6</jats:sub> shell completely encapsulates CsPb<jats:italic>X</jats:italic> <jats:sub>3</jats:sub> NCs and greatly improves the composition stability of CsPb<jats:italic>X</jats:italic> <jats:sub>3</jats:sub> NCs. Moreover, our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM<jats:sub>3</jats:sub> (<jats:italic>M</jats:italic> = Cl, Br, I) NCs.</jats:p>

<jats:p>Graphene with a Dirac cone-like electronic structure has been extensively studied because of its novel transport properties and potential application for future electronic devices. For epitaxially grown graphene, the process conditions and the microstructures are strongly dependent on various substrate materials with different lattice constants and interface energies. Utilizing angle-resolved photoemission spectroscopy, here we report an investigation of the electronic structure of single-crystalline graphene grown on Cu/Ni (111) alloy film by chemical vapor deposition. With a relatively low growth temperature, graphene on Cu/Ni (111) exhibits a Dirac cone-like dispersion comparable to that of graphene grown on Cu (111). The linear dispersions forming Dirac cone are as wide as 2 eV, with the Fermi velocity of approximately 1.1×10<jats:sup>6</jats:sup> m/s. Dirac cone opens a gap of approximately 152 meV at the binding energy of approximately 304 meV. Our findings would promote the study of engineering of graphene on different substrate materials.</jats:p>

<jats:p>Heterostructures (HSs) have attracted significant attention because of their interlayer van der Waals interactions. The electronic structures and optical properties of stacked GaN–MoS<jats:sub>2</jats:sub> HSs under strain have been explored in this work using density functional theory. The results indicate that the direct band gap (1.95 eV) of the GaN–MoS<jats:sub>2</jats:sub> HS is lower than the individual band gaps of both the GaN layer (3.48 eV) and the MoS<jats:sub>2</jats:sub> layer (2.03 eV) based on HSE06 hybrid functional calculations. Specifically, the GaN–MoS<jats:sub>2</jats:sub> HS is a typical type-II band HS semiconductor that provides an effective approach to enhance the charge separation efficiency for improved photocatalytic degradation activity and water splitting efficiency. Under tensile or compressive strain, the direct band gap of the GaN–MoS<jats:sub>2</jats:sub> HS undergoes redshifts. Additionally, the GaN–MoS<jats:sub>2</jats:sub> HS maintains its direct band gap semiconductor behavior even when the tensile or compressive strain reaches 5% or -5%. Therefore, the results reported above can be used to expand the application of GaN–MoS<jats:sub>2</jats:sub> HSs to photovoltaic cells and photocatalysts.</jats:p>