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Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown Mn Bi2Te4 thin films

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National Science Review 2024年第2期11卷 24-32页

作者： Yunhe bai Yuanzhao Li Jianli Luan Ruixuan Liu Wenyu Song Yang Chen Peng-Fei Ji Qinghua Zhang Fanqi meng Bingbing Tong Lin Li Yuying Jiang Zongwei Gao Lin Gu Jinsong Zhang Yayu Wang Qi-Kun Xue Ke He Yang Feng Xiao Feng State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Institute of Physics Chinese Academy of Sciences School of Materials Science and Engineering Tsinghua University Beijing Academy of Quantum Information Sciences Frontier Science Center for Quantum Information Hefei National Laboratory Southern University of Science and Technology

The intrinsic magnetic topological insulator MnBi2Te4provides a feasible pathway to the high-temperature quantum anomalous Hall（QAH） effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4thin flakes, it remains a big challenge to achieve molecular beam epitaxy（MBE）-grown MnBi2Te4thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4and to find a way out of the big difficulty in obtaining MnBi2Te4samples showing quantized transport properties.

关键词： intrinsic magnetic topological insulator quantized anomalous Hall resistivity molecular beam epitaxy quantized transport property

Effectiveness of magnetic resonance imaging and spiral computed tomography in the staging and treatment prognosis of colorectal cancer

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2135-2144页

作者： Lu-Na bai Lu-Xian Zhang Department of Radiology Zhongshan Hospital Xiamen UniversityXiamen 361004Fujian ProvinceChina

BACKGROUND Colorectal cancer(CRC)is a prevalent cancer type in clinical settings;its early signs can be difficult to detect,which often results in late-stage diagnoses in many *** early detection and diagnosis of CRC are crucial for improving treatment success and patient survival ***,imaging techniques have been hypothesized to be essential in managing CRC,with magnetic resonance imaging(MRI)and spiral computed tomography(SCT)playing a significant role in enhancing diagnostic and treatment *** To explore the effectiveness of MRI and SCT in the preoperative staging of CRC and the prognosis of laparoscopic *** Ninety-five individuals admitted to Zhongshan Hospital Xiamen University underwent MRI and SCT and were diagnosed with *** precision of MRI and SCT for the presurgical classification of CRC was assessed,and pathological staging was used as a *** operating characteristic curves were used to evaluate the diagnostic efficacy of blood volume,blood flow,time to peak,permeability surface,blood reflux constant,volume transfer constant,and extracellular extravascular space volume fraction on the prognosis of patients with *** Pathological biopsies confirmed the following CRC stages:23,23,32,and 17 at T1,T2,T3,and T4,*** were 39 cases at the N0 stage,22 at N1,34 at N2,44 at M0 stage,and 51 at *** pathological findings as the benchmark,the combined use of MRI and SCT for preoperative TNM staging in patients with CRC demonstrated superior sensitivity,specificity,and accuracy compared with either modality alone,with a statistically significant difference in accuracy(P<0.05).Receiver operating characteristic curve analysis revealed the predictive values for laparoscopic treatment prognosis,as indicated by the areas under the curve for blood volume,blood flow,time to peak,and permeability surface,blood reflux constant,volume transfer constant,and extracellular extravascular space volu

关键词： Magnetic resonance imaging Spiral computed tomography Colorectal cancer Prognosis Receiver operating characteristic curve Retrospective study

An Effective Meshless Approach for Inverse Cauchy Problems in 2D and 3D Electroelastic Piezoelectric Structures

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2955-2972页

作者： Ziqiang bai Wenzhen Qu Guanghua Wu School of Automation Qingdao UniversityQingdao266071China School of Mathematics and Statistics Qingdao UniversityQingdao266071China Weifang University of Science and Technology Weifang262700China

In the past decade,notable progress has been achieved in the development of the generalized finite difference method(GFDM).The underlying principle of GFDM involves dividing the domain into multiple *** each sub-domain,explicit formulas for the necessary partial derivatives of the partial differential equations(PDEs)can be obtained through the application of Taylor series expansion and moving-least square approximation ***,the method generates a sparse coefficient matrix,exhibiting a banded structure,making it highly advantageous for large-scale engineering *** this study,we present the application of the GFDM to numerically solve inverse Cauchy problems in two-and three-dimensional piezoelectric *** our preliminary numerical experiments,we demonstrate that the proposed GFDMapproach shows great promise for accurately simulating coupled electroelastic equations in inverse problems,even with 3%errors added to the input data.

关键词： Generalized finite difference method meshless method inverse Cauchy problems piezoelectric problems electroelastic analysis

Chiral mesostructured hematite with temperature-independent magnetism due to spin confinement

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Nano Research 2024年第3期17卷 2019-2024页

作者： baiwen Zhang Jing Ai Yingying Duan Te bai Lu Han Shunai Che School of Physics Science and Engineering Tongji UniversityShanghai 200092China School of Chemistry and Chemical Engineering Tongji UniversityShanghai 200092China Wuxi Vocational College of Science and Technology Wuxi 214028China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

Hematite(α-Fe_(2)O_(3))is known to undergo conversion from weak ferromagnetic to antiferromagnetic as the temperature decreases below the Morin temperature(TM=250 K)due to spin moment rotation occurring during the Morin transition(MT).Herein,we endowed hematite with mesostructured chirality to maintain weak ferromagnetism without *** mesostructured hematite(CMH)nanoparticles were prepared by a hydrothermal method with glutamic acid(Glu)as the symmetry-breaking *** triangular bipyramidal CMH nanoparticles were composed of helically cleaved nanoflakes with twisted crystal ***-cooled(FC)magnetization measurements showed that the magnetic moments of CMH were stabilized without MT within the temperature range of 10–300 *** loop measurements confirmed the weak ferromagnetism of *** enhanced Dzyaloshinskii–Moriya interaction(DMI)was speculated to be responsible for the temperature-independent weak ferromagnetism,in which the spin configuration would be confined with canted antiferromagnetic coupling due to the mesostructured chirality of CMH.

关键词： hematite chiral mesostructure Dzyaloshinskii–Moriya interaction weak ferromagnetism antiferromagnetic material temperature-independent magnetism

不同方法构建小鼠过敏性结膜炎免疫耐受模型的比较

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国际眼科杂志 2022年第10期22卷 1615-1620页

作者：白梦天李韵胡竹林中国四川省遂宁市中心医院眼科 629000 云南大学附属医院眼科云南省昆明市650032 中国四川省遂宁市中心医院肿瘤科 629000

目的:采用不同方法构建乳鼠过敏性结膜炎免疫耐受模型,观察生命早期环境因素对过敏性结膜炎的影响。方法:Balb/c乳鼠50只随机分为空白对照组、卵清蛋白(OVA)+皮下注射组、OVA+雾化吸入组、OVA+灌胃组、豚草花粉(RW)+皮下注射组、RW+雾... 详细信息

目的:采用不同方法构建乳鼠过敏性结膜炎免疫耐受模型,观察生命早期环境因素对过敏性结膜炎的影响。方法:Balb/c乳鼠50只随机分为空白对照组、卵清蛋白(OVA)+皮下注射组、OVA+雾化吸入组、OVA+灌胃组、豚草花粉(RW)+皮下注射组、RW+雾化吸入组、RW+灌胃组、屋尘螨(HDM)+皮下注射组、HDM+雾化吸入组、HDM+灌胃组(n=5只/组)。除空白对照组外,各处理组乳鼠分别诱导免疫耐受,成年后再予以相应抗原。通过眼前段照相观察眼表情况,RT-qPCR法检测结膜RANTES、IL-17 mRNA相对表达水平,并通过ELISA法检测血清IL-17浓度。结果:与空白对照组相比,结膜IL-17 mRNA相对表达水平在RW+灌胃组增高最为显著,RW+皮下注射组增高程度最低(均P<0.05);结膜RANTES mRNA相对表达水平在RW+灌胃组增高最为显著(P<0.001)。与空白对照组相比,除OVA+雾化吸入组和RW+皮下注射组外,其他处理组小鼠血清IL-17浓度增高(P<0.05)。结论:小鼠生命早期皮下注射诱导过敏性结膜炎免疫耐受状态最佳。

关键词：过敏性结膜炎免疫耐受动物模型豚草花粉屋尘螨卵清蛋白

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Structural disruption of melanin-like polymers with boosted UV protection

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Science China Chemistry 2024年第5期67卷 1653-1663页

作者： Zhen Yang Xianheng Wang Wanjie bai Zikun Zou Haoxing Wu Yiwen Li Department of Radiology Huaxi MR Research CenterFunctional and Molecular Imaging Key Laboratory of Sichuan ProvinceNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengdu 610041China College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Manipulating the energy structure of materials represents an efficient way to regulate their light absorption behaviors. For example, constructing donor-acceptor(D-A) structures to increase the polarizability and reduce the energy bandgap of local molecules has been widely used in the field of organic photovoltaics with ordered structures. Remarkably, even in disordered and chaotic systems such as melanin-like polydopamine(PDA), visible and near-infrared light absorption can be significantly improved using this strategy. However, there has been a noticeable dearth of research on the ultraviolet(UV) light absorption regulation of bioinspired polymers with disordered and chaotic architectures by tailoring the D-A microstructures. In this study, a series of benzoheterocyclic molecules with strong electron-donating features screened by molecular simulation calculations were involved in disrupting the D-A structures within PDA. The destruction of D-A structures promoted the increase of the energy band gap and finally boosted the UV absorption of PDA. The resulting PDA nanoparticles with enhanced UV absorption were further employed to fabricate UV shielding composite films to protect the growth of plants from harmful UV radiation. This research may open up new avenues for structural disruption of bioinspired polymers for enhanced photoprotection applications.

关键词： melanin-like polymers polydopamine D-A structure UV absorption photoprotection

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A Simplified Method for the Stress Analysis of Underground Transfer Structures Crossing Multiple Subway Tunnels

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2893-2915页

作者： Shen Yan Dajiang Geng Ning Dai Mingjian Long Zhicheng bai College of Civil Engineering Tongji UniversityShanghai200092China China Construction 4th Engineering Bureau 6th Corp. Ltd.Shanghai201199China Department of Civil and Architecture Engineering Hubei Polytechnic UniversityHuangshi435003China

According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock *** address this challenge,a subterranean transfer structure spanning multiple subway tunnels was *** on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam *** resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer *** research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent *** established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate *** pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment.

关键词： Crossing tunnels transfer structure force mechanism simplify analysis layered soil mass

Nanomaterial Assisted Exosome Analysis Using Mass Spectrometry

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Chemical Research in Chinese Universities 2024年第2期40卷 237-254页

作者： ZHANG Yi ZHOU Bokai LI Qiuning JIN Mingshi bai Yu Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P.R.China Department of Chemistry Yanbian UniversityYanji133002P.R.China

Exosomes,extracellular vesicles(EVs)that play crucial roles in biological processes,have emerged as attractive targets for noninvasive disease diagnosis and *** spectrometry(MS)offers high sensitivity,high throughput,and excellent qualification and quantification capacity,which is the ideal approach for exosome ***’unique physiochemical properties,controllable morphology,and large surface area make them promising in biological sample pretreatment and *** contributed diverse functions to the exosome MS analysis,encompassing substrates for exosome isolation and cargos enrichment,matrices for laser desorption/ionization(LDI),read-out signals and supporters for signal amplification strategies,*** this review,recent progress in the applications of nanomaterial in the exosome MS analysis was summarized and a comprehensive discussion on the challenges and perspectives was proposed for the development of an advancing analysis approach of exosomes for the accurate diagnosis and monitoring of diseases.

关键词： Exosome Nanomaterial Enrichment Matrix Mass spectrometry

Self-doping active sites in microbe-derived carbonaceous electrocatalysts for the oxygen reduction reaction performance

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Nano Research 2024年第8期17卷 6803-6819页

作者： Xiaofeng Xiao Xiaochun Tian Junpeng Li Fan Yang Rui bai Feng Zhao Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Microorganisms are rich in heteroatoms,which can be self-doped to form active sites during pyrolysis and loaded on microbederived carbonaceous *** recent years,microbe-derived carbonaceous materials,characterized with abundant selfdoping sites,have been continuously developed as cost-effective electrocatalysts for oxygen reduction reaction(ORR).To fully unlock the catalytic potential of microbe-derived carbonaceous materials,a comprehensive analysis of catalytic sites and mechanisms for ORR is *** paper provides a summary of the ORR catalytic performance of microbe-derived carbonaceous materials reported to date,with a specific focus on the self-doping sites introduced during their pyrolytic *** highlights the mono-or co-doping sites involving nonmetallic elements such as oxygen(O),nitrogen(N),phosphorus(P),and sulfur(S)atoms,as well as covers the doping of metallic iron(Fe)atoms with various coordination configurations in microbe-derived carbonaceous *** the impact of these self-doping sites on ORR catalytic performance can guide the design of doping sites in microbe-derived carbonaceous *** approach has the potential to maximize electrocatalytic activity of microbe-derived carbonaceous materials and contributes to the development of more efficient and cost-effective carbonaceous electrocatalysts.

关键词： electrocatalysis heteroatoms self-doped single atom catalyst microbe-derived carbonaceous material