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Non-perturbative dynamics of flat-band systems with correlated disorder

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Chinese Physics B 2024年第9期33卷 547-551页

作者： Qi Li Junfeng liu ke liu Zi-Xiang Hu Zhou Li GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhou 510535China Guangdong Provincial key Laboratory of Terahertz Quantum Electromagnetics Guangzhou 510700China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Department of Physics and Chongqing key Laboratory for Strongly Coupled Physics Chongqing UniversityChongqing 401331China University of Chinese Academy of Sciences Beijing 100039China

We develop a numerical method for the time evolution of Gaussian wave packets on flat-band lattices in the presence of correlated *** achieve this,we introduce a method to generate random on-site energies with prescribed *** verify this method with a one-dimensional(1D)cross-stitch model,and find good agreement with analytical results obtained from the disorder-dressed evolution *** allows us to reproduce previous findings,that disorder can mobilize 1D flat-band states which would otherwise remain *** explained by the corresponding disorder-dressed evolution equations,such mobilization requires an asymmetric disorder-induced coupling to dispersive bands,a condition that is generically not fulfilled when the flat-band is resonant with the dispersive bands at a Dirac point-like *** exemplify this with the 1D Lieb *** analytical expressions are not available for the two-dimensional(2D)system due to its complexity,we extend the numerical method to the 2D a–T3 model,and find that the initial flat-band wave packet preserves its localization when a=0,regardless of disorder and ***,when a̸=0,the wave packet shifts in real *** interpret this as a Berry phase controlled,disorder-induced wave-packet *** addition,we present density functional theory calculations of candidate materials,specifically Hg1−*** flat-band emerges near the G point(α=0)in the Brillouin zone.

关键词： flat-band system dynamics correlated disorder

Observation of ballistic-diffusive thermal transport in GaN transistors using thermoreflectance thermal imaging

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Rare Metals 2024年第1期43卷 389-394页

作者： Zhi-ke liu Yang Shen Han-Ling Li Bing-Yang Cao key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

To develop effective thermal management strategies for gallium-nitride (GaN) transistors, it is essential to accurately predict the device junction temperature. Since the width of the heat generation in the devices is comparable to phonon mean free paths (MFPs) of GaN, phonon ballistic transport exists and can significantly affect the heat transport process.

关键词： temperature. transistors GaN

Synergistic Effects of Carbon Nanotube(CNT)and Reduced Graphene Oxide(RGO)on Mechanical and Thermal Properties of ZK61 Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 577-585页

作者： Fanjing Meng Wenbo Du Ning Ding Jian Sun Xian Du ke liu Shubo Li College of Materials Science and Engineering Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

The hybrid of carbon nanotube(CNT)and reduced graphene oxide(RGO)reinforced ZK61 composite was fabricated by a hot extrusion *** with the raw ZK61 alloy and single-reinforced composites,the hybrid-reinforced by RGO+CNT complex exhibited significant enhancements both in mechanical and thermal *** adjusting the proportion of RGO and CNT in ZK61 alloy,the obtained optimum ZK61/(0.06 wt%RGO+0.54 wt%CNT)composite exhibited increase of 25.4%in yield strength,26.5%in ultimate tensile strength,104%in failure strain and 30.4%in thermal conductivity,respectively,in comparison with ZK61 *** superior properties of the nano-hybrid composite are attributed to the synergetic effects of RGO and CNT,leading to a uniform dispersion and integrated structure as well as the enhanced interfacial bonding with *** strengthening ability of RGO and CNT was calculated to quantify their individual contribution to the improvement in mechanical and thermal properties of the ZK61 matrix *** RGO+CNT hybrids provide a promising way to develop Mg matrix composites with impressive performances.

关键词： Mg matrix composite Carbon nanotube Reduced graphene oxide Mechanical performance Thermal conductivity

Small but mighty:Empowering sodium/potassium-ion battery performance with S-doped SnO_(2) quantum dots embedded in N,S codoped carbon fiber network

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Carbon Energy 2024年第5期6卷 186-200页

作者： Shengnan He Hui Wu Shuang Li ke liu Yaxiong Yang Hongge Pan Xuebin Yu Institute of Science and Technology for New Energy Xi'an Technological UniversityXi'anChina Department of Materials Science Fudan UniversityShanghaiChina Wanxiang A123 Systems Corporation HangzhouChina School of Material Science and Engineering Shanghai UniversityShanghaiChina

SnO_(2) has been extensively investigated as an anode material for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs)due to its high Na/K storage capacity,high abundance,and low ***,the sluggish reaction kinetics,low electronic conductivity,and large volume changes during charge and discharge hinder the practical applications of SnO_(2)-based electrodes for SIBs and *** rational structures with fast charge/ion transfer and robust stability is important to overcoming these ***,S-doped SnO_(2)(S-SnO_(2))quantum dots(QDs)(≈3 nm)encapsulated in an N,S codoped carbon fiber networks(S-SnO_(2)-CFN)are rationally fabricated using a sequential freeze-drying,calcination,and S-doping *** analysis and density functional theory calculations reveal that the integration of S-SnO_(2) QDs with N,S codoped carbon fiber network remarkably decreases the adsorption energies of Na/K atoms in the interlayer of SnO_(2)-CFN,and the S doping can increase the conductivity of SnO_(2),thereby enhancing the ion transfer *** synergistic interaction between S-SnO_(2) QDs and N,S codoped carbon fiber network results in a composite with fast Na+/K+storage and extraordinary long-term ***,the S-SnO_(2)-CFN delivers high rate capacities of 141.0 mAh g^(−1) at 20 A g^(−1) in SIBs and 102.8 mAh g^(−1) at 10 A g^(−1) in ***,it delivers ultra-stable sodium storage up to 10,000 cycles at 5 A g^(−1) and potassium storage up to 5000 cycles at 2 A g^(−1).This study provides insights into constructing metal oxide-based carbon fiber network structures for high-performance electrochemical energy storage and conversion devices.

关键词： carbon fiber network heteroatom doping potassium-ion battery sodium-ion battery S-SnO_(2)quantum dot

Effects of deformation temperatures on microstructures,aging behaviors and mechanical properties of Mg-Gd-Er-Zr alloys fabricated by hard-plate rolling

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Journal of Magnesium and Alloys 2024年第6期12卷 2345-2359页

作者： ke liu Dalong Hu Feng Lou Zijian Yu Shubo Li Xian Du Wenbo Du Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

In this investigation,a high-strength Mg-12Gd-1.0Er-0.5Zr(wt.%)alloy sheet was produced by hot extrusion(HE)and subsequent hard-plate rolling(HPR)at different *** results indicate that the microstructures of these final-rolled sheets are inhomogeneous,mainly including coarse deformed grains and dynamic recrystallized(DRXed)grains,and the volume fraction of these coarse deformed grains increases as the rolling temperature ***,more DRXed grains can be found in R-385℃sheet,resulting in a smaller average grain size and weaker basal texture,while the biggest grains and the highest strong basal texture are present in R-450℃*** of dynamic precipitation ofβphases which are mainly determined by the rolling temperature are present in these sheets,and its precipitation can consume the content of Gd solutes in the *** a result,the lowest number density ofβphase in R-450℃sheet is beneficial to modify the age hardening ***,the R-450℃sheet displays the best age hardening response because of a severe traditional precipitation ofβ’(more)andβH/βM(less)precipitates,resulting in a sharp improvement in strength,*** tensile strength(UTS)of∼518±17 MPa and yield strength(YS)of∼438±18 ***,the elongation(EL)of this sheet reduces greatly,and its value is∼2.7±0.3%.By contrasting,the EL of the peak-aging R-385℃sheet keeps better,changing from∼4.9±1.2%to∼4.8±1.4%due to a novel dislocation-induced chain-like precipitate which is helpful to keep good balance between strength and ductility.

关键词： Mg-Gd-Er-Zr sheets Age hardening response Precipitates Mechanical properties

Magnetic emission intensity enhancement for amorphous alloys by constructing a multi-phase structure withα-Fe nanocrystals

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Nano Research 2024年第7期17卷 6630-6637页

作者： ke liu Zhi Qin Jie Shen Zhi Cheng Shiyue You Liang Ma Jing Zhou Wen Chen State key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China Sanya Science and Education Innovation Park Wuhan University of TechnologySanya 572024China Hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration ZoneXiangyang 441000China

The perturbation in the magnetic field generated by the rotation or oscillation of magnetic domains in magnetic materials can emit low-frequency electromagnetic waves,which are expected to be used in low-frequency ***,the magnetic emission intensity,defined by the perturbation ability,of current commercially applied amorphous alloys,such as Metglas,cannot meet the application requirements for low-frequency antennas due to the domain motion energy ***,a multi-phase Metglas amorphous alloy was constructed by incorporatingα-Fe nanocrystals using rapid annealing to manipulate the domain *** was found that 3.89 times higher magnetic emission intensity is obtained compared to the pristine due to the synergism of the deformation and displacement ***,the low-frequency magnetic emission performance verification was carried out by preparing magnetoelectric composites as the antenna vibrator by assembling the alloy and macro piezoelectric fiber composites(MFC).Enhancements of magnetic emission intensity are found at 93.3%and 49.2%at the first and second harmonic frequencies compared with the unmodified alloy ***,the approach leads to the development of high-performance communication with a novel standard for evaluation.

关键词： multi-phase amorphous alloys magnetic emission intensity enhancing mechanism magnetic domain pinning theory Jiles-Atherton model analysis

Lithium isotopic fractionation in minerals from pegmatites: Perspective of crystal chemistry

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Journal of Earth Science 2024年

作者： Shan-ke liu Ben-xun Su key Laboratory of Mineral Resources， Institute of Geology and Geophysics， Chinese Academy of Sciences

Lack of information regarding lithium (Li) crystal chemistry in numerous minerals， especially those containing trace amounts of Li (ranging from few to tens of ppm)， limits our understanding of Li isotopic fractionation in pegmatites. In this study， we examined the Li isotopic composition and Li content in various Li-poor (e.g.， quartz or feldspar) together with Li-rich (sopdumene or lepidolite) mineral phases within granitic pegmatites. We compiled a comprehensive dataset， encompassing a broad spectrum of Li contents (ranging from a few to tens of thousands of ppm) and Li isotopic values (-8‰ to 41‰). The minerals exhibited distinct Li isotopic signatures. Specifically， elbaite and beryl showed the highest values， while biotite displayed a negative average. Compared to individual minerals， whole rocks demonstrated lower Li isotopic values， with pegmatites exhibiting the highest and non-granitic pegmatite wall rocks showing the lowest. Our study also uncovered a clear "V" shape relationship between Li isotopic values and logarithm of Li content， with different mineral groups occupying specific regions within this shape. Furthermore， a significant correlation was observed between average Li isotopic values and Li-O(OH， F) bond lengths in various minerals. These discoveries underscore the crucial role of crystal chemistry in shaping the Li isotopic behavior in pegmatites from a statistical perspective.

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Carotid versus axillary artery cannulation for descending aorta remodeling in type A acute aortic dissection

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World Journal of Cardiology 2024年第10期16卷 564-573页

作者： Qin Jiang Tao Yu ke-Li Huang ke liu Xi Li Sheng-Shou Hu Department of Cardiac Surgery Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072Sichuan ProvinceChina Cardiac Surgery Center Sichuan Academy of Medical Sciences&Sichuan Provincial People’s HospitalChengdu 610072Sichuan ProvinceChina

BACKGROUND Arterial cannulation sites for the surgical repair of type A aortic dissection(AAD)have evolved from right axillary artery(AA)cannulation to bilateral carotid artery(CA)based of femoral artery(FA)*** descending aorta remodeling is closely linked to the false lumen area ratio(FLAR),defined as false lumen area/aortic area,as well as to the incidence of renal replacement therapy(RRT).AIM To investigate the effect of the updated arterial cannulation strategy on descending aortic *** A total of 443 AAD patients who received FA combined cannulation between March 2015 and March 2023 were included in the *** these,209 received right AA cannulation and 234 received bilateral CA *** primary outcome was the change in FLAR,as calculated from computed tomography angiography in three segments of the descending aorta:Thoracic(S1),upper abdominal(S2),and lower abdominal(S3).Secondary outcomes were the incidence of RRT and the serum inflammation response,as observed by the levels of high sensitivity C reaction protein(hs-CRP)and Interleukin-6(IL-6).RESULTS The postoperative/preoperative ratio of FLAR in S2 and S3 was higher in the AA group compared to the CA group(S2:0.80±0.08 vs 0.75±0.07,P<0.001;S3:0.57±0.12 vs 0.50±0.12,P<0.001,respectively).The AA group also had a significantly higher incidence of RRT(19.1%vs 8.5%,P=0.001;odds ratio:2.533,95%CI:1.427-4.493)and higher levels of inflammation cytokines 24 h after the procedure[hr-CRP:117±17 vs 104±15 mg/L;IL-6:129(103,166)vs 83(69,101)pg/mL;both P<0.001]compared to the CA *** The CA cannulation strategy was associated with better abdominal aorta remodeling after AAD repair compared to AA cannulation,as observed by a greater change in FLAR and lower incidence of RRT.

关键词： Acute type A aortic dissection Bilateral carotid arterial cannulation Descending aortic remodeling False lumen area ratio Prognosis

New clinical trial design in precision medicine:discovery,development and direction

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Signal Transduction and Targeted Therapy 2024年第4期9卷 1293-1321页

作者： Xiao-Peng Duan Bao-Dong Qin Xiao-Dong Jiao ke liu Zhan Wang Yuan-Sheng Zang Department of Medical Oncology Changzheng HospitalNaval Medical UniversityShanghaiChina

In the era of precision medicine,it has been increasingly recognized that individuals with a certain disease are complex and different from each *** to the underestimation of the significant heterogeneity across participants in traditional"one-sizefits-all"trials,patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket,umbrella,and platform trial designs under the master protocol *** recent years,the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous *** the rapid increase in the number of basket,umbrella,and platform trials,the current clinical and research understanding of these new trial designs,as compared with traditional trial designs,remains *** majority of the research focuses on methodologies,and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial ***,we provide this comprehensive review of the discovery and development of basket,umbrella,and platform trials and their underlying logic from the perspective of precision ***,we discuss future directions on the potential development of these new clinical design in view of the"Precision Pro","Dynamic Precision",and"Intelligent Precision".This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic,which be essential to accelerate the progression of precision medicine.

关键词： clinical approval successive