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Time-reversal asymmetries in Λb→Λ（→pπ-）l+l-

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Chinese Physics C 2024年第3期 5-18页

作者：耿朝强刘佳韦魏正乙 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS University of Chinese Academy of Sciences CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences

We study the decays of Λb→Λ（→pπ-）l+l-with l=（e,μ,τ）.We examine the full angular distributions with polarized Λb,where the T-odd observables are identified.We discuss the possible effects of new physics（NP） and find that the T-odd observables are sensitive to them as they vanish in the standard model.Special attention is given to the interference of（pseudo）scalar operators with（axial）vector operators in polarizedΛb→Λ（→pπ-）τ+τ-,which are studied for the first time.Their effects are proportional to the lepton masses and therefore may evade the constraint from Λb→Λ（→pπ-）μ+μ-at the LHCb naturally.As Λb→Λ（→pπ-）τ+τ-is uncontaminated by the charmonia resonance,it provides a clean background to probe NP.In addition,we show that the experimental central value of K10in Λb→Λ（→pπ-）μ+μ-at the LHCb can be explained by the NP case,which couples to the right-handed quarks and leptons.The polarizatin fraction of Λpat the LHCb is found to be consistent with zero regardless of the NP scenarios.

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Illuminating functions of evolutionarily conserved long non-coding RNAs

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Science China Life Sciences 2024年

作者： Ruiqiao He Fangqing Zhao Institute of Zoology Chinese Academy of Sciences Key Laboratory of Systems Health Science of Zhejiang Province Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences

Long non-coding RNAs (lncRNAs) serve as crucial regulators of gene expression,influencing various physiological processes and disease states (Cabili et al.,2011; Ulitsky and Bartel, 2013; Yao et al.,2019). Dysregulation of certain notable lncRNAs, such as HOTAIR and MALAT1,has been implicated in a wide range of pathological processes, including tumorigenesis in various human cancers (Gupta et al., 2010; Kim et al., 2018).

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Exploring cosmic origins through primordial black hole mass functions

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 214-214页

作者： Ying-Li Zhang School of Physics Science and Engineering Tongji UniversityShanghai 200092China Institute for advanced study of Tongji University Shanghai 200092China

Primordial black holes(PBHs)are objects formed from early universe density fluctuations,offering insights into the universe's infancy.The PBH mass function characterizes their mass distribution,which is crucial for understanding their role in shaping various structures[1].Typically,the focus of various studies is on the mass function of supermassive black holes(SMBHs),which originate due to unknown mechanics.However,PBHs can serve as the seeds for SMBHs owing to their extensive mass range and long lifetime.Therefore,the physics of the early universe may have left imprints on the SMBH properties via these massive PBH seeds.

关键词： universe massive origin

Geological characteristics of unconventional tight oil reservoir (10^(9) t): A case study of Upper Cretaceous Qingshankou Formation, northern Songliao Basin, NE China

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China geology 2024年第1期7卷 51-62页

作者： Li-zhi Shi Zhuo-zhuo Wang Zhan-tao Xing Shan Meng Shuai Guo Si-miao Wu Li-yan Luo Chinese Academy of Geological Sciences Beijing 100037China Beijing Institute of Engineering geology Beijing 100048China

The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical guidi

关键词： Unconventional oil and gas Tight oil Thin-bedded mudstone-siltstone-sandstone reservoir Qijia area Qingshankou Formation Oil and gas exploration engineering Songliao Basin Daqing oilfield

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： Ye Jiang Wen-Biao Han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic interaction.In this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky equation.On the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and waveforms.With the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently calculated.This will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

Review on current development of polybenzimidazole membrane for lithium battery

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Journal of Energy Chemistry 2024年第4期91卷 579-608页

作者： Yonggui Deng Arshad Hussain Waseem Raza Xingke Cai Dongqing Liu Jun Shen College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060GuangdongChina Interdisciplinary Research Center for Hydrogen Technologies and Carbon Management(IRC-HTCM) King Fahd University of Petroleum&MineralsKFUPM Box 504031261 DhahranSaudi Arabia Institute for advanced study Shenzhen UniversityShenzhen 518060GuangdongChina

With the rapid development of portable technology,lithium batteries have emerged as potential candidates for high-performance energy storage systems owing to their high energy density and cycling stability.Among the key components of a lithium battery system,the separator plays a critical role as it directly influences the battery performance benchmark(cycling performance and safety).However,traditional polyolefin separators(polypropylene/polyethylene)are unable to meet the demands of highperformance and safer battery systems due to their poor electrolyte compatibility,thermal runaways,and ultimate growth of dendrites.In contrast,membranes fabricated using polybenzimidazole(PBI)exhibit excellent electrolyte wettability and outstanding thermal dimensional stability,thus holding great potential as separators for high-performance and high-safety batteries.In this paper,we present a comprehensive review of the general requirements for separators,synthesis technology for separators,and research trends focusing PBI membranes in lithium batteries to alleviate the current commercial challenges faced by conventional polyolefin separators.In addition,we discuss the future development direction for PBI battery separators by considering various factors such as production cost,ecological footprint,preparation technology,and battery component compatibility.By exploring these perspectives,we aim to promote the continued application and exploration of PBI-based materials to advance lithium battery technology.

关键词： Lithium batteries Separators Porous separators Polybenzimidazole Membrane

High-temperature elemental segregation induced structure degradation in high-entropy fluorite oxide

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Journal of advanced Ceramics 2024年第3期13卷 310-322页

作者： Yixuan Hu Mariappan Anandkumar Yumeng Zhang Joydip Joardar Atul Suresh Deshpande Xiaodong Wang Kolan Madhav Reddy School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Materials Science and Metallurgical Engineering Indian Institute of Technology HyderabadSangareddy 502285India International advanced Research centre for Powder Metallurgy and New Materials(ARCI) Hyderabad 500005India

Fluorite-structured oxides constitute an important category of oxides with a wide range of high-temperature applications.Following the concept of high entropy,high-entropy fluorite oxides(HEFOs)have showcased intriguing high-temperature application potential.However,unlocking this potential necessitates an assessment of their long-term stability under high-temperature conditions.In this study,we conducted a prolonged heat treatment at 1000℃on typical HEFO,specifically(CeHfZrGdLa)O_(x).After 100 h,high-intensity X-ray diffraction(XRD)revealed a transition from a single-phase fluorite to a multi-phase configuration.Further investigation by analytical electron microscoy(AEM)demonstrated that this degradation resulted from facilitated element diffusion and consequent escalating chemical fluctuation at high temperatures,leading to spontaneous segregation and separation of Ce and La elements,forming Ce-rich,La-poor,and La-rich phases.Notably,the La-rich phase spontaneously transformed from a fluorite structure(space group Fm3m)to a bixbyite structure(space group Ia3)at elevated temperatures,resulting in the appearance of superstructure reflection in XRD profiles and electron diffraction patterns.Despite the intricate phase decomposition,the energy band gap showed minimal variation,suggesting potential property stability of(CeHfZrGdLa)O_(x)across a broad range of compositions.These findings offer valuable insights into the future applications of HEFOs.

关键词： phase transition high-temperature stability elemental segregation high-entropy fluorite oxides(HEFOs)

Ferroelectric-controlled graphene plasmonic surfaces for all-optical neuromorphic vision

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Science China(Technological Sciences) 2024年第3期67卷 765-773页

作者： CHEN JianBo LIU Yu LI ShangDong LIN Lin LI YaDong HUANG Wen GUO JunXiong School of Electronic Information and Electrical Engineering Institute for Advanced StudyChengdu UniversityChengdu 610106China School of Integrated Circuits Tsinghua UniversityBeijing 100084China School of Integrated Circuits(National Exemplary Schoolof Microelectronics) Universityof Electronic Science and Technologyof China Chengdu 610054China Jincheng Research Institute of Opto-mechatronics Industry Jincheng 048000China Shanxi Key Laboratory of advanced Semiconductor Optoelectronic Devices and Integrated Systems Jincheng 048000China Engineering Research Center of Digital Imaging and Display Ministry of EducationSoochow UniversitySuzhou 215006China

Artificial visual systems can recognize desired objects and information from complex environments, and are therefore highly desired for pattern recognition, object detection, and imaging applications. However, state-of-the-art artificial visual systems with high recognition performances that typically consist of electronic devices face the challenges of requiring huge storage space and high power consumption owing to redundant data. Here, we report a terahertz(THz) frequency-selective surface using a graphene split-ring resonator driven by ferroelectric polarization for efficient visual system applications. The downward polarization of the ferroelectric material offers an ultrahigh electrostatic field for doping p-type graphene with an anticipated Fermi level. By optimizing the geometric parameters of the devices and modulating the carrier behaviors of graphene, our plasmonic devices exhibit a tunable spectral response in a range of 1.7–6.0 THz with continuous transmission values. The alloptical neural network using graphene plasmonic surfaces designed in this study exhibited excellent performance in visual preprocessing and convolutional filtering and achieved an ultrahigh recognition accuracy of up to 99.3% in training the Modified National Institute of Standards and Technology(MNIST) handwritten digit dataset. These features demonstrate the great potential of graphene plasmonic devices for future smart artificial vision systems.

关键词： graphene plasmon ferroelectric frequency selective surface artificial vision system

In-situ analysis of laser-induced breakdown spectra for online monitoring of femtosecond laser machining of sapphire

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Science China(Technological Sciences) 2024年第1期67卷 73-82页

作者： SHANGGUAN ShiYong ZHANG JianGuo LI ZhanZhu SHI Wei WANG WenKe QI DongFeng ZHENG HongYu Center for advanced Laser Manufacturing(CALM) Shandong University of TechnologyZibo 255000China

Laser-induced breakdown spectroscopy(LIBS)is widely used for elemental analysis.However,its application for monitoring and analyzing a laser machining process by examining the changes in spectral information warrants further investigation.In this study,we investigate the effect of laser parameters on the spectra,variations in the time-resolved plasma emission spectra,and the relationship between the morphology of craters and plasma plume evolution during the femtosecond(fs)laser ablation of sapphire.The Boltzmann plot method and Stark’s broadening model are employed to estimate the temporal temperature and electron density of the plasma plume,revealing the process of plasma evolution.This study aims to demonstrate the feasibility of LIBS for online monitoring of laser processing through experimental data and theoretical explanations.

关键词： laser-induced breakdown spectroscopy plasma plume online monitoring sapphire