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基于混合近邻局部分布差异的离群点检测算法

计算机与数字工程 2024年第2期52卷 301-306页

作者：张君范铭金举西安交通大学软件学院西安710049 西安交通大学网络空间安全学院西安710049

离群点检测作为数据挖掘领域的重要任务,其目的是从表示事件或对象行为的数据中找出不一致数据。目前大部分传统的无监督离群点检测算法,如基于距离或密度的方法,识别多维度空间离群数据时都存在因维度诅咒导致检测精度衰退的问题。论... 详细信息

离群点检测作为数据挖掘领域的重要任务,其目的是从表示事件或对象行为的数据中找出不一致数据。目前大部分传统的无监督离群点检测算法,如基于距离或密度的方法,识别多维度空间离群数据时都存在因维度诅咒导致检测精度衰退的问题。论文提出了基于混合近邻的离群点检测算法,该算法以数据项的混合近邻作为新的局部影响空间,以双向共享近邻和欧式距离重新定义了数据项的相似度计算方式,通过对比数据项与其局部影响空间中样本的平均局部分布差异衡量数据的局部离群程度,从而识别离群点。在合成和真实数据集上和其他同类算法的对比实验结果证明,该算法在离群点检测方面具有一定的提高。

关键词：无监督离群点检测混合近邻局部分布差异

LLZTO涂覆天丝无纺布锂离子电池隔膜的制备

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电子元件与材料 2024年第2期43卷 146-153,161页

作者：幸楚粤李尧张奥捷龙金胡健华南理工大学轻工科学与工程学院广东广州510640

针对锂离子电池用无纺布隔膜孔径分布不均的问题,采用原纤化天丝纤维制备湿法无纺布基材,结合氧化物固态电解质涂层,在收窄孔径尺寸及区间分布的同时,降低电池内阻,提升电化学性能。固态电解质涂层搭配低转数无纺布隔膜会导致基材侧渗... 详细信息

针对锂离子电池用无纺布隔膜孔径分布不均的问题,采用原纤化天丝纤维制备湿法无纺布基材,结合氧化物固态电解质涂层,在收窄孔径尺寸及区间分布的同时,降低电池内阻,提升电化学性能。固态电解质涂层搭配低转数无纺布隔膜会导致基材侧渗出大量陶瓷,但对于组装后电池循环及倍率测试无影响。涂覆之后的无纺布隔膜(LC10)组装钴酸锂全电池循环后拥有较低的极化电压,且由于拥有较高的离子迁移数及更低的欧姆电阻和电荷转移电阻,其在3C高倍率循环下的容量保持率可达85.93%。未涂覆固态电解质涂层的无纺布隔膜低温性能差于商品样,低温镀锂情况较商品样更加严重,而LC10低温下的初始比容量可达124.9 mAh/g,容量保留率为94.23%。

关键词：无纺布隔膜固态电解质涂层天丝纤维锂离子电池

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硅基自旋光电子学太赫兹辐射源特性

物理学报 2024年第16期73卷 190-198页

作者：程宏阳马倩茹徐浩然张慧萍金钻明何为彭滟上海理工大学太赫兹技术创新研究院上海市现代光学系统重点实验室光学仪器与系统教育部工程中心太赫兹光谱与影像技术协同创新中心上海200093 同济大学上海智能科学与技术研究院上海200092 中国科学院物理研究所磁学国家重点实验室北京100190

将光电子器件集成到硅片上是光电子集成器件研发的首要步骤.自旋光电子学太赫兹辐射源,通常是由纳米厚度的铁磁/非磁性金属多层膜结构组成,在飞秒激光辐照下能产生高质量、宽带太赫兹脉冲辐射.本文利用飞秒激光脉冲在生长于硅衬底上的ta...

将光电子器件集成到硅片上是光电子集成器件研发的首要步骤.自旋光电子学太赫兹辐射源,通常是由纳米厚度的铁磁/非磁性金属多层膜结构组成,在飞秒激光辐照下能产生高质量、宽带太赫兹脉冲辐射.本文利用飞秒激光脉冲在生长于硅衬底上的ta.CoFeB/Ir铁磁/非磁性金属异质结中实现了高效、宽带的太赫兹相干脉冲辐射.首先,ta.CoFeB/Ir异质结的太赫兹脉冲的极性随外加磁场的反转而反转,太赫兹辐射的物理机制可以归结为超快自旋流-电荷流转换.其次,通过改变抽运激光的激发能量密度,研究了ta.CoFeB/Ir异质结的太赫兹辐射饱和现象.此外,通过研究ta.CoFeB/Ir异质结的太赫兹发射特性随Ir层厚度的依赖关系,不仅优化了器件的辐射强度,而且获得了Ir层在太赫兹频率下的自旋扩散长度(~(0.59±0.12)nm).该值小于通过自旋抽运技术获得的GHz频率下的自旋扩散长度(1.34 nm),表明不同频率范围对应于不同的电子输运机理.

关键词：宽带太赫兹辐射铁磁异质结逆自旋霍尔效应自旋扩散长度

肠道菌群对知母皂苷A-Ⅲ的代谢及其药效的影响

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药学学报 2024年第8期59卷 2372-2380页

作者：黄雯瑾潘凌云高鑫芯祝维泽李后开上海中医药大学中药学院上海201203

知母皂苷A-Ⅲ (timosaponin A-Ⅲ,ta.Ⅲ)腹腔注射给药对于高脂饮食诱导的代谢相关脂肪性肝病(meta.olic dysfunction-associated steatotic liver disease,MASLD)具有治疗作用,而口服给药则无效,提示肠道菌群可能影响ta.Ⅲ的口服生物利... 详细信息

知母皂苷A-Ⅲ (timosaponin A-Ⅲ,ta.Ⅲ)腹腔注射给药对于高脂饮食诱导的代谢相关脂肪性肝病(meta.olic dysfunction-associated steatotic liver disease,MASLD)具有治疗作用,而口服给药则无效,提示肠道菌群可能影响ta.Ⅲ的口服生物利用度。代谢相关脂肪性肝炎(meta.olic dysfunction-associated steatohepatitis,MASH)是MASLD发展的炎症浸润阶段。本文将探讨ta.Ⅲ不同给药方式对MASH小鼠的治疗作用差异及其与肠道菌群代谢药物的关系。本研究利用缺乏胆碱、限定L-氨基酸的高脂饮食(choline-deficient,L-amino acid-defined,high-fat diet CDAHFD)诱导MASH小鼠模型,比较ta.Ⅲ (10 mg·kg^(-1))腹腔注射(intraperitoneal injection,ip)和ta.Ⅲ (100 mg·kg^(-1))灌胃给药(intragastric administration,ig)的治疗效果,并分析两种给药方式下大鼠血清中ta.Ⅲ的浓度。在此基础上,通过小鼠肠道菌群体外代谢ta.Ⅲ实验和体内联合抗生素干预小鼠的药代动力学实验等方法验证小鼠肠道菌群对ta.Ⅲ的代谢作用;最后比较不同抗生素干预条件下,灌胃给药后小鼠血清中ta.Ⅲ的浓度,结合16S rRNA测序分析,发现可能参与ta.Ⅲ代谢的关键菌。本文动物实验过程遵循上海中医药大学动物伦理委员会的规定,动物伦理批准编号为:PZSHUTCM2307030004,PZSHUTCM2310200003。结果显示,ta.Ⅲ腹腔注射给药对MASH小鼠有明确治疗作用,而十倍剂量的口服给药无效;分析发现,ta.Ⅲ灌胃给药(100 mg·kg^(-1),ig)在小鼠血清和肝脏中原型浓度显著低于腹腔注射(10 mg·kg^(-1),ip),提示口服ta.Ⅲ后可能经肠道菌群代谢。链霉素(streptomycin,Str)干预的小鼠血清中ta.Ⅲ浓度高于正常小鼠,结合16S rRNA基因测序分析发现Akkermansia_muciniphila (***)丰度在Str组显著减少,且体外实验表明***可以代谢ta.Ⅲ。上述结果表明,肠道菌群是影响ta.Ⅲ经胃肠道给药药效的重要因素,其中***可能扮演了重要角色。

关键词：知母皂苷A-Ⅲ 代谢相关脂肪性肝炎肠道菌群药物代谢 Akkermansia_muciniphila

Mo and ta.addition in NbTiZr medium entropy alloy to overcome tensile yield strength-ductility trade-off

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Journal of Materials Science & Technology 2022年第14期109卷 176-185页

作者： Muhammad Akmal Hyun Woo Seong Ho jin Ryu Department of Materials Science and Engineering KAISTDaejeonYuseong-gu 34141South Korea Department of Nuclear and Quantum Engineering KAISTDaejeonYuseong-gu 34141South Korea

In this study,single-phase NbTiZr and NbTiZr(Mota._(0.1) medium-entropy alloys(MEAs)were investigated for their use in biomedical *** alloys were prepared by arc melting,and were then cold-rolled,annealed,and characterized in terms of phase analysis,mechanical properties,fractography,and wear *** alloys showed a single body-centered cubic phase with superior mechanical,and tribological properties compared to commercially available biomedical *** and ta.conta.ning MEAs showed higher tensile yield strength(1060±18 MPa)and higher tensile ductility(~20%),thus overcoming the strength-ductility trade-off with no signs of transformation-induced plasticity,twinning,or *** generalized sta.king fault energy(GSFE)calculations on the{112}slip system by the first-principles calculations based on density functional theory showed that the addition of less than0.2 molar fraction of Mo and ta.lowers the GSFE *** behavior posits the increase in ductility of the alloy by facilita.ing slips although strength is also increased by solid solution *** wear resista.ce of both alloys against hardened steel surfaces was superior to that of commercial biomedical ***,we concluded that NbTiZr(Mota._(0.1)MEA with good tensile ductility is a potential candidate for biomedical implants.

关键词： Medium-entropy alloys Wear-resista.t Biomedical implants Solid solution hardening Sta.ing fault energy

Strengthening mechanisms of reduced activation ferritic/martensitic steels:A review

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International Journal of Minerals,Meta.lurgy and Materials 2021年第3期28卷 335-348页

作者： jin-hua Zhou Yong-feng Shen Nan Jia Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China The Sta.e Key Lab of Rolling&Automation Northeastern UniversityShenyang 110819China

This review summarizes the strengthening mechanisms of reduced activation ferritic/martensitic(RAFM)***-angle grain boundaries,subgrain boundaries,nano-sized M_(23)C_(6),and MX carbide precipita.es effectively hinder dislocation motion and increase high-temperature strength.M23C6 carbides are easily coarsened under high temperatures,thereby weakening their ability to block *** properties are improved through the reduction of M23C6 ***,the loss of strength must be compensated by other strengthening *** review also outlines the recent progress in the development of RAFM *** dispersion-strengthened steels prevent M23C6 precipita.ion by reducing C content to increase creep life and introduce a high density of nano-sized oxide precipita.es to offset the reduced *** plastic deformation methods can substa.tially refine subgrains and MX carbides in the *** thermal deformation strengthening of RAFM steels mainly relies on thermo-mechanical treatment to increase the MX carbide and subgrain *** procedure increases the creep life of TMT(thermo-mechanical treatment)9Cr-1W-0.06ta.steel by~20 times compared with those of F82H and Eurofer 97 steels under 550℃/260 MPa.

关键词： reduced activation ferritic/martensitic steel strengthening mechanism high-angle grain boundary subgrain boundary precipita.e

Long Wave Reflection and Transmission over A Sloping Step

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海洋工程：英文版 2004年第3期18卷 371-380页

作者： Hsien-Kuo CHANG jin-Cheng LIOU Department of Civil Engineering National Chiao Tung University 1001 Ta Hsuech Road Hsinchu 300 ChinaDepartment of Civil Engineering National Chiao Tung University 1001 Ta Hsuech Road Hsinchu 300 China

This investigation examines long wave reflection and transmission induced by a sloping step. Bellman and Kalaba's (1959) invariant imbedding is introduced to find wave reflection. An alternative method matching both the surface elevation and its surface slope of each region at the junction is applied to the determination of wave reflection and transmission. The proposed methods are compared with the accurate numerical results of Porter and Porter (2000) and those of Mei (1983) for a vertical step. The wave reflection obta.ned for a mildly sloping step differs significantly from the result of Mei. The wave reflection is found to fluctuate owing to wave trapping for the mild sloping step. The height and the face slope of the step are importa.t for determining wave reflection and transmission coefficients.

关键词： long wave reflection coefficient wave transmission wave trapping

Growth of large-scale two-dimensional insulator Na2ta.O11 through chemical vapor deposition

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Journal of Semiconductors 2020年第7期41卷 23-27页

作者： Yuanyuan jin Huimin Li Song Liu Institute of Chemical Biology and Nanomedicine(ICBN) State Key Laboratory of Chem/Bio-Sensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China

The insulator Na2ta.O11 has been considered as a potential ***,little attention has been given to the synthesis of Na2ta.O11 nanoparticles,let alone the growth of two-dimensional(2D)layered Na2ta.O11 flake,which may bring innovative properties and promising ***,the 2D thin-layer Na2ta.O11 flake was first produced by chemical vapor deposition(CVD)method,with the smallest thickness reported *** have also synthesized 2D Na2ta.O11 flake over 100μm,which was the largest value over the 2D level reported to *** work proposed novel strategies to synthesize other 2D meta. oxide material and endow the Na2ta.O11 more properties and applications.

关键词： Na2ta.O11 two-dimensional materials chemical vapor deposition insulator

Effects of Re on surface eutectic formation for Ni-base single crysta. superalloys during directional solidification

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Journal of Materials Science & Technology 2017年第11期33卷 1308-1313页

作者： Liang Cao Yizhou Zhou ta. jin Xiaofeng Sun Institute of Meta. Research Chinese Academy of Sciences Shenyang 110016 China

Effects of Re on the formation of surface eutectics have been investigated by using Ni-base single crysta. superalloys with different Re additions. It was found that Re promotes the segregation of Al and ta.to the eutectic melt, leading to an increase of the surface and internal eutectics. In addition, the addition of Re also increased the freezing range, the local solidification time, and the permeability of the dendritic network within the mushy zone. These factors ultimately promoted the outflow of the interdendritic residual liquid with the action of solidification shrinkage, and led to the formation of more surface eutectics. In contrast, the addition of Re had no obvious influence on the surface eutectic microstructures.

关键词： Surface eutectic Re addition Single crysta. Superalloy