摘要：
For photocatalytic materials, the composites formed by metal oxides and heteroatom-doped carbon have outstanding activity. Among them, metal-organic framework (MOF) derived composites, usually composed of metal oxide and nitrogen-doped carbon, is not only simple to prepare, but also have far-exceeding catalytic performance than homogenous semiconductor. However, the relationship between the structure and performance in the photocatalytic system is still not clear. Here, we explored the tunable nitrogen configurations in sample N-ZnO@NC by controlling the thermal conversion of ZIF-8. Crucially, through ex situ and in-situ XPS characterization, it is found that the ZnO and nitrogen-doped carbon in N-ZnO@NC are connected by C-N-Zn bond, which enhances charge separation efficiency and becomes the origin of superior photocatalytic performance. DFT calculations further reveal the influence of different Zn-bonding nitrogen configurations on the adjusting of Fermi level and electron transfer. This study exhibits that the pyridine-N configuration in MOF-derived material is the main contributor for the improved performance and tunes Fermi level more appropriately than the pyrrolic-N, which can hold the key for future design of next-generation photocatalysts. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.
作者机构：
[Shi, Jiaming; Zheng, Ruifeng] Cent China Normal Univ, Inst Astrophys, Wuhan 430079, Peoples R China.;[Qiu, Taotao] Huazhong Univ Sci & Technol, Sch Phys, Wuhan 430074, Peoples R China.
关键词：
primordial black hole;scalar-induced gravitational waves;dark matter
摘要：
It is well known that a primordial black hole (PBH) can be generated in the inflation process of the early universe, especially when the inflation field has a number of non-trivial features that could break the slow-roll condition. In this study, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We determined that the potential with multi-bump can generate power spectra with multi-peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical and elliptical collapses. Finally, we discuss the scalar-induced gravitational waves (SIGWs) generated by linear scalar perturbations at second-order.
作者机构：
[Katsuragawa, Taishi; Chen, Hua] Cent China Normal Univ, Inst Astrophys, Wuhan 430079, Peoples R China.;[Matsuzaki, Shinya] Jilin Univ, Ctr Theoret Phys, Changchun 130012, Peoples R China.;[Matsuzaki, Shinya] Jilin Univ, Coll Phys, Changchun 130012, Peoples R China.
关键词：
modified gravity;dark energy;inflation
摘要：
<jats:title>Abstract</jats:title>
<jats:p>
<jats:inline-formula>
<jats:tex-math><?CDATA $ R^2 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M1.jpg" xlink:type="simple" />
</jats:inline-formula>-corrected dark energy (DE) models in <jats:inline-formula>
<jats:tex-math><?CDATA $ F(R) $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M2.jpg" xlink:type="simple" />
</jats:inline-formula> gravity have been widely investigated in recent years, which not only removes the weak singularity potentially present in DE models but also provide us with a unified picture of the cosmic history, including the inflationary and DE epochs. Towards the unified interpretation of dynamical DE all over the cosmic history in the class of <jats:inline-formula>
<jats:tex-math><?CDATA $ R^2 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M3.jpg" xlink:type="simple" />
</jats:inline-formula>-corrected DE models, we explore the universal features of the scalaron dynamics in the radiation-dominated epoch, along with the chameleon mechanism, by keeping our eyes on the inflationary and DE epochs. We show that the scalaron evolution does not follow a <jats:italic>surfing solution</jats:italic> and is mostly adiabatic before big bang nucleosynthesis (BBN), even properly including the <jats:italic>kick</jats:italic> by the nonperturbative QCD phase transition, hence a catastrophic consequence claimed in the literature is not applied to this class of DE models. This is due to the presence of the gigantic scale hierarchy between <jats:inline-formula>
<jats:tex-math><?CDATA $ R^2 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M4.jpg" xlink:type="simple" />
</jats:inline-formula> correction and DE, so is the universal feature for the class of <jats:inline-formula>
<jats:tex-math><?CDATA $ R^2 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M5.jpg" xlink:type="simple" />
</jats:inline-formula>-corrected DE models. The prospects for the post- or onset-inflationary epoch would be pretty different from what the standard <jats:inline-formula>
<jats:tex-math><?CDATA $ R^2 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_10_105106_M6.jpg" xlink:type="simple" />
</jats:inline-formula> inflationary scenario undergoes due to the presence of the chameleon mechanism.</jats:p>
摘要：
A prototype beam monitor was designed to provide tracking information for heavy-ion projectiles for the cool storage ring (CSR) external target experiment (CEE) at the Heavy Ion Research Facility in Lanzhou (HIRFL). High granularity and direct charge sensing are the main features of this device. It measures the beam position in a two-dimensional (2D) plane transverse to the beam direction on an event-by-event basis. The current design consists of two field cages inside a single vessel that operates independently and has electrical drift fields in orthogonal directions. Preliminary tests of the prototype were performed using a
$${{}^{241}\mathrm{Am}}$$
$$\alpha$$
source. The results show that a spatial resolution of less than 40
$${\upmu \mathrm{m}}$$
and a time resolution of less than 600ns can be achieved.
作者机构：
[Yang, Minghui; Song, Hongwei; Xiang, Haipan] Chinese Acad Sci, State Key Lab Magnet Resonance & Atom & Mol Phys, Innovat Acad Precis Measurement Sci & Technol, Wuhan 430071, Peoples R China.;[Xiang, Haipan] Huazhong Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Lu, Yunpeng] Nanyang Technol Univ, Sch Phys & Math Sci, Div Chem & Biol Chem, Singapore 637371, Singapore.;[Yang, Minghui] Huazhong Univ Sci & Technol, Wuhan Natl Lab Optoelect, Wuhan 430071, Peoples R China.
通讯机构：
[Yunpeng Lu] D;[Hongwei Song] S;State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences , Wuhan 430071, China<&wdkj&>Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
作者机构：
[Yang, Shuyun] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOS, Wuhan 430079, Peoples R China.
关键词：
magnetic field;NJL model;decay constant;mass spectra
摘要：
<jats:title>Abstract</jats:title>
<jats:p>We study the mass spectra and decay process of <jats:italic>σ</jats:italic> and
<jats:inline-formula>
<jats:tex-math><?CDATA $ \pi_0 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_4_043107_M1.jpg" xlink:type="simple" />
</jats:inline-formula> mesons under a strong external magnetic field. To achieve this goal, we deduce the thermodynamic potential in a two-flavor, hot and magnetized Nambu–Jona-Lasinio model. We calculate the energy gap equation through the random phase approximation (RPA). Then we use the Ritus method to calculate the decay triangle diagram and self-energy in the presence of a constant magnetic field <jats:italic>B</jats:italic>. Our results indicate that the magnetic field has little influence on the mass of
<jats:inline-formula>
<jats:tex-math><?CDATA $ \pi_0 $?></jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_46_4_043107_M2.jpg" xlink:type="simple" />
</jats:inline-formula> at low temperatures. However, for quarks and <jats:italic>σ</jats:italic> mesons, their mass clearly changes, which reflects the influence of magnetic catalysis (MC). The presence of a magnetic field accelerates the decay of the meson while the presence of a chemical potential will decrease the decay process.
</jats:p>
作者机构：
[Xiao, Yu-Xin; Kang, Jin-Wen; Zhang, He-Xia; Zhang, Ben-Wei] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Whang 430079, Peoples R China.;[Xiao, Yu-Xin; Kang, Jin-Wen; Zhang, He-Xia; Zhang, Ben-Wei] Cent China Normal Univ, Inst Particle Phys, Whang 430079, Peoples R China.;[Zhang, He-Xia; Zhang, Ben-Wei] South China Normal Univ, Inst Quantum Matter, Guangdong Prov Key Lab Nucl Sci, Guangzhou 510006, Peoples R China.
通讯机构：
[He-Xia Zhang] K;Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan, China<&wdkj&>Guangdong Provincial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South China Normal University, Guangzhou, China
摘要：
With the two-flavor Nambu–Jona–Lasinio (NJL) model, we carried out a phenomenological study on the chiral phase structure, mesonic properties, and transport properties of momentum-space anisotropic quark matter. To calculate the transport coefficients we utilized the kinetic theory in the relaxation time approximation, where the momentum anisotropy is embedded in the estimation of both the distribution function and relaxation time. It was shown that an increase in the anisotropy parameter
$$\xi$$
may result in a catalysis of chiral symmetry breaking. The critical endpoint (CEP) is shifted to lower temperatures and larger quark chemical potentials as
$$\xi$$
increases, and the impact of momentum anisotropy on the CEP temperature is almost the same as that on the quark chemical potential of the CEP. The meson masses and the associated decay widths also exhibit a significant
$$\xi$$
dependence. It was observed that the temperature behavior of the scaled shear viscosity
$$\eta /T^3$$
and scaled electrical conductivity
$$\sigma _\text {el}/T$$
exhibited a similar dip structure, with the minima of both
$$\eta /T^3$$
and
$$\sigma _\text {el}/T$$
shifting toward higher temperatures with increasing
$$\xi$$
. Furthermore, we demonstrated that the Seebeck coefficient S decreases when the temperature rises and its sign is positive, indicating that the dominant carriers for converting the temperature gradient to the electric field are up-quarks. The Seebeck coefficient S is significantly enhanced with a large
$$\xi$$
for a temperature below the critical temperature.
摘要：
在色玻璃凝聚框架下，将Sudakov效应运用到矢量介子产生中，计算了衍射遍举和衍射离解两种过程中轻（φ）和重（J/ψ）介子产生的微分截面和总截面。首先，利用数值方法求解微分积分形式的领头阶偶极子演化方程和Sudakov抑制的次领头阶偶极子演化方程，得到相应的偶极子散射振幅，研究发现Sudakov抑制的次领头阶偶极子散射振幅小于同一快度下领头阶的偶极子散射振幅，随着快度增加两者之间的差距越来越大，由此表明Sudakov效应压低了偶极子散射振幅的演化速度。其次，将这些偶极子散射振幅应用到衍射矢量介子产生模型中，描述HERA（hadron electron ring accelerator）能区φ和J/ψ介子产生相关实验数据，得到Sudakov抑制时的χ~2/Np=1.26远小于领头阶时的χ~2/Np=1.87，由此Sudakov效应提高了模型的精度，使得修正后的偶极子散射振幅能较好地描述相关数据，表明了Sudakov效应在矢量介子产生中起着重要的作用。
作者机构：
[瞿少成; 陈尧; 罗静; 赵亮; 刘艺] College of Physical Science and Technology, Central China Normal University, Wuhan;430079, China;[瞿少成; 陈尧; 罗静; 赵亮; 刘艺] 430079, China
通讯机构：
[Chen, Y.] C;College of Physical Science and Technology, Central China Normal University, Wuhan, China
通讯机构：
[Lin, H ] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
关键词：
ROTATION;topological;VORTEX
摘要：
Synchronized rotation of unit cells in a periodic structure provides a novel design perspective for manipulation of band topology. We then design a two-dimensional version of higher-order topological insulator (HOTI) by such rotation in a triangular photonic lattice with C3 symmetry. This HOTI supports the hallmark zero-dimensional corner states and, simultaneously, the one-dimensional edge states. We also find that our photonic corner states carry chiral orbital angular momenta locked by valleys, whose wave functions are featured by the phase vortex (singularity) positioned at the maximal Wyckoff points. Moreover, when excited by a fired source with various frequencies, the valley topological states of both one-dimensional edges and zero-dimensional corners emerge simultaneously. Extendable to higher or synthetic dimensions, our paper provides access to a chiral vortex platform for HOTI realizations in the terahertz photonic system.
