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A study on vector mediator top-philic dark matter

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Communications in Theoretical Physics 2024年第8期76卷 69-80页

作者： Yanyan Hu Yandong Liu Yuanyuan Liu College of Nuclear Science and Technology Beijing Normal University Joint Laboratory of Jinping Ultra-low Radiation Background Measurement of Ministry of Ecology and Environment Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province Key Laboratory of Beam Technology of Ministry of Education Beijing Radiation Center

We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle, facilitating exclusive interactions between dark matter and the top quark in the Standard Model. The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model. Notably, in instances when dark matter mass is small, the tree-level two-body annihilation process experiences suppression. In such scenarios, the contributions of the threebody process(■) and the one-loop process(■ → gg) dominate the relic *** regard to direct detection, calculations were performed for the two-loop contribution to the dark-matter–gluon interaction, yielding the corresponding spin-independent scattering cross section.

关键词： dark matter effective field theory new physics

Higgs inflation model with non-minimal coupling in hybrid Palatini approach

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Chinese Physics C 2024年第4期48卷 193-201页

作者： Brahim Asfour Aatifa Bargach Ahmed Errahmani Taoufik Ouali laboratory of Physics of matter and Radiation University of Mohammed firstBP 717OujdaMorocco

In this paper,we propose a hybrid metric Palatini approach in which the Palatini scalar curvature is non minimally coupled to the scalar *** derive Einstein’s field equations,i.e.,the equations of motion of the scalar ***,the background and perturbative parameters are obtained by means of Friedmann equations in the slow roll *** analysis of cosmological perturbations allowed us to obtain the main inflationary parameters,e.g.,the scalar spectral index and tensor to scalar ratio *** this perspective,as an application of our analysis,we consider the Higgs field with quartic potential,which plays the inflaton role,and show that predictions of Higgs hybrid inflation are in good agreement with recent observational data[***.641,61(2020)].

关键词： non-minimal coupling hybrid metric Palatini Higgs inflation

Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation

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National Science Review 2024年第2期11卷 155-167页

作者： Peng He Meng-Yang Hu Jin-Hong Li Tian-Zhang Qiao Yi-Lin Lu Shou-Fei Zhu Frontiers Science Center for New Organic matter State Key Laboratory and Institute of Elemento-Organic Chemistry Nankai University

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively,and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.

关键词： spin effect spin-delocalization spin crossover iron-catalysis alkyne hydrosilylation

Chain Dynamics Heterogeneity in Plasticized Poly(vinyl butyral)(PVB) as Elucidated by Solid-State NMR

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Chinese Journal of Polymer Science 2024年第1期42卷 113-124,I0010页

作者： Jing Lv Xu Chen Zi-Shuo Wu Ya-Hui Li Wei Chen National Synchrotron Radiation laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Scienceand Technology of ChinaHefei 230026China

The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR *** plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich *** time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific *** quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is *** ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation *** origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen ***,the existence of a mobility gradient in the VB unit has been ***,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first *** indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.

关键词： Poly(vinyl butyral) Dynamics heterogeneity Plasticizer Solid state NMR

The medium-temperature dependence of jet transport coefficient in high-energy nucleus-nucleus collisions

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Nuclear Science and Techniques 2024年第7期35卷 173-191页

作者： Man Xie Qing-Fei Han En-Ke Wang Ben-Wei Zhang Han-Zhong Zhang Key laboratory of Atomic and Subatomic Structure and Quantum Control(MOE) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of MatterInstitute of Quantum Matter South China Normal UniversityGuangzhou510006China Guangdong-Hong Kong Joint laboratory of Quantum matter Guangdong Provincial Key Laboratory of Nuclear ScienceSouthern Nuclear Science Computing CenterSouth China Normal UniversityGuangzhou 510006China Key laboratory of Quark and Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan430079China

The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in high-energy nucleus-nucleus *** a next-to-leading-order perturbative QCD parton model for hard scatterings with modified fragmentation functions due to jet quenching controlled by q,we check the suppression and azimuthal anisotropy for large p_(T) hadrons,and extract q by global fits to RAA(pT)and v_(2)(pT)data in A+A collisions at RHIC and LHC,*** numerical results from the best fits show that q∕T^(3) goes down with local medium-temperature T in the parton jet *** with the case of a constant q∕T^(3),the going-down T dependence of q∕T^(3) makes a hard parton jet to lose more energy near T_(c) and therefore strengthens the azimuthal anisotropy for large pT *** a result,v_(2)(p_(T))for large pT hadrons was enhanced by approximately 10%to better fit the data at RHIC/*** the first-order phase transition from QGP to the hadron phase and the additional energy loss in the hadron phase,v_(2)(p_(T))is again enhanced by 5-10%at RHIC/LHC.

关键词： Jet quenching Jet transport parameter Hadron suppression Elliptic flow coefficient Energy loss asymmetry

Dual-functional poly(2-methyl-2-oxazoline)/poly(2-(dimethylamine)ethyl methacrylate)mixed brushes with switchable protein adsorption and antibacterial properties

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Chinese Journal of Chemical Engineering 2024年第2期66卷 19-30页

作者： Kang He Liangyu Zhu Yanmei Wang CAS Key laboratory of Soft matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated PMOXA and SH-terminated PDMAEMA onto polydopamine-anchored *** mixed-brush coating was characterized by variable-angle spectroscopic ellipsometry,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,zeta potential measurements,water contact angle,and atomic force *** mixed brushes showed tunable surface charge,wettability,and surface roughness,depending on the degree of PDMAEMA swelling under varying pH and ionic strength(Ⅰ).Then the adsorption behaviors of pepsin,bovine serum albumin(BSA),γ-globulin,and lysozyme,four very different proteins with regard to isoelectric point,on the mixed brushes coating were studied by using fluorescence microscopy and surface plasmon *** the chain length of PDMAEMA was about twice as long as PMOXA,the mixed brushes not only had high adsorption capacity for pepsin,BSA,and y-globulin but also had a desorption efficiency of 86.9%,87.1%,and 93.5%,*** is explained that electrostatic attraction between the protonated PDMAEMA and positively charged acidic proteins(pepsin and BSA,whose isoelectric points were below the pK_(a) of PDMAEMA)would drive the intensive adsorption(at pH 3,I=10^(-3)mol·L^(-1)for pepsin,and pH 5,I=10^(-5)mol·L^(-1)for BSA),while desorption was dominated by the hydrophilic PMOXA when PDMAEMA was shrinking(at pH 7,I=10^(-1)mol·L^(-1)for pepsin,and pH 9,I=10^(-1)mol·L^(-1)for BSA).Furthermore,the isoelectric precipitation led to the adsorption of neutral protein(γ-globulin,whose isoelectric point was near the pK_a of PDMAEMA)at pH 7,I=10^(-5)mol·L^(-1),while electrostatic repulsion and antifouling PMOXA triggered the desorption of y-globulin at pH 3,I-10^(-1)mol·L^(-1).However,alkaline protein(lysozyme,whose isoelectric point was higher than

关键词： Switchable conformation transition Controllable protein adsorption Mixed brushes Isoelectric point Antibacterial surface

Spin-polarized pairing induced by the magnetic field in the Bernal bilayer graphene

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Chinese Physics B 2024年第4期33卷 650-654页

作者：黄妍周涛 Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of matter Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum MaterialsSchool of PhysicsGuangdong-Hong Kong Joint Laboratory of Quantum Matterand Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

Recent experimental findings have demonstrated the occurrence of superconductivity in Bernal bilayer graphene when induced by a magnetic *** this study,we conduct a theoretical investigation of the potential pairing symmetry within this superconducting *** developing a theoretical model,we primarily calculate the free energy of the system with p+ip-wave parallel spin pairing,p+ip-wave anti-parallel spin pairing and d+i d-wave pairing *** results confirm that the magnetic field is indeed essential for generating the *** discover that the p+ip-wave parallel spin pairing leads to a lower free energy for the *** numerical calculations of the energy band structure,zero-energy spectral function and density of states for each of the three pairing symmetries under consideration show a strong consistency with the free energy results.

关键词： superconductivity magnetic field induction pairing symmetry Bernal bilayer graphene

Structure regulating of metal clusters in carbonized metallic organic frameworks for high-efficient microwave absorption via tuning interaction strength between metals and ligands

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Nano Research 2024年第3期17卷 1699-1709页

作者： Chang Sun Kun-Yan Zhao Ming-Lu Huang Cheng-Long Luo Xu-Dong Chen Ming Wang School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function ManufacturingSouthwest UniversityChongqing 400715China Jieyang Branch of Chemistry and Chemical Engineering Guangdong laboratory(Rongjiang laboratory) Jieyang 515200China

Carbonized metallic organic frameworks(CMOF)have been attracting attention in microwave absorption(MA)research area because of their diverse structures,tunable compositions,and rich ***,structure regulation on metal clusters in CMOF is achieved by tuning the interaction strength between metals and ligands to enhance microwave absorption *** to relatively weak interaction among copper cations and ligands,copper nanoclusters(CuNC)can be uniformly formed and embedded within the cobalt/zinc(Co/Zn)***,copper cations are added to the Co/Zn bimetallic zeolitic imidazolate frameworks(ZIFs).Secondly,the CMOF composite particles with CuNCs(CuNCs/CoZn-CMOF)were developed by a pyrolysis *** CuNCs/CoZn-CMOF with an appropriate amount of CuNCs can harmonize both dielectric and magnetic *** a result,the minimum reflection loss(RLmin)reaches–45.1 dB at a matching thickness of 2.30 mm and the effective absorption bandwidth(EAB)is 8.80 GHz at a thickness of 3.10 *** broadband response to electromagnetic waves is attributed to interfacial polarization at CuNCs surface and heterogeneous interfaces,impedance matching and multiple scattering of electromagnetic *** study provides a feasible method to develop CMOF microwave absorption materials with high EAB values.

关键词： heterogeneous interface carbonized metallic organic frameworks microwave absorption interfacial polarization

Implementation of integrated nonlocal sensing for object shape and rotational speed

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 6-12页

作者： Zhenyu Guo Yunlong Wang Zehong Chang Jiawei Wang Junliang Jia Pei Zhang Ministry of Education Key laboratory for Nonequilibrium Synthesis and Modulation of Condensed matter Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic DevicesSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China

The expeditious acquisition of information pertaining to objects through the utilization of quantum technology has been a perennial issue of *** far,the efficient utilization of information from dynamic objects with limited resources remains a significant ***,we realize a nonlocal integrated sensing of the object's amplitude and phase information by combining digital spiral imaging with the correlated orbital angular momentum *** amplitude information is utilized for object identification,while the phase information enables us to determine the rotational *** demonstrate the nonlocal identification of a rotating object's shape,irrespective of its rotational symmetry,and introduce the concept of the correlated rotational Doppler effect,establishing a fundamental connection between this effect and the classical rotational Doppler effect,i.e.,that both rely on extracting crucial information from the spiral spectrum of *** present study highlights a promising pathway towards the realization of quantum remote sensing and imaging.

关键词： digital spiral imaging orbital angular momentum correlated rotational Doppler effect