检索结果-南通市图书馆

Experimental observation of interlayer perpendicular standing spin wave mode with low damping in skyrmion-hosting[Pt/Co/ta]_(10)multilayer

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第11期31卷 548-554页

作者： Zhen-Dong Chen Mei-Yang ma Sen-Fu Zhang mang-Yuan ma Zi-Zhao Pan Xi-Xiang Zhang Xue-Zhong Ruan Yong-Bing Xu Fu-Sheng ma Jiangsu Key Laboratory of Opto-Electronic Technology Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210046China Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic materials School of Electronic Science and EngineeringNanjing UniversityNanjing 210093China School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China Physical Science and Engineering Division(PSE) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

An interlayer perpendicular standing spin wave mode is observed in the skyrmion-hosting[Pt/Co/ta]_(10) multilayer by measuring the time-resolved magneto-optical Kerr *** observed interlayer mode depends on the interlayer spin-pumping and spin transfer torque among the neighboring Co *** mode shows monotonically increasing frequency-field dependence which is similar to the ferromagnetic resonance mode,but within higher frequency ***,the damping of the interlayer mode is found to be a relatively low constant value of 0.027 which is independent of the external *** work expounds the potential application of the[heavy-metal/ferromagnetic-metal]_(n) multilayers to skyrmion-based magnonic devices which can provide multiple magnon modes,relatively low damping,and skyrmion states,simultaneously.

关键词： dynamic properties of magnetization spin waves domain structure magnetic properties of interfaces

Microstructure and room-temperature tensile property of Ti-5.7Al-4.0Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1.0ta-0.05C with near equiaxed β grain fabricated by laser directed energy deposition technique

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2022年第6期101卷 308-320页

作者： MengCheng Deng Shang Sui Bo Yao Liang ma Xin Lin Jing Chen State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

Near-equiaxed β grain was achieved in the near-α Ti60(Ti-5.7Al-4.0Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1.0ta-0.05C) titanium alloy via laser directed energy deposition(LDED). The microstructural evolution along the building direction and the room-temperature tensile properties along the horizontal and vertical directions(building direction) were systematically studied through SEM and OM. EBSD and XRD were utilized to accurately demonstrate the texture of the α and β phases. The results showed that the α phase presented a low texture intensity, which was ascribed to the weak textured β grain with near-equiaxed morphology, since there are Burgers orientation relationships during the β →α transition. In addition, numerical simulation, combined with the CET curve of Ti60 alloy considering the effect of multi-composition,was utilized to elucidate the formation mechanism of the near-equiaxed β grains. Furthermore, according to the solidification theory, we proposed that the solidification temperature range ΔTfwas more accurate than the growth restriction factor Q in predicting the formation tendency of equiaxed β grain in different titanium alloys. Tensile results showed that the horizontal and vertical samples had similar strength,while the former exhibited larger elongation than the latter. The effect of the near-equiaxed β grain and the internal α phase on mechanical properties were revealed at last.

关键词： Laser directed energy deposition Near-αtitanium alloy Equiaxedβgrain Room-temperature tensile property

Exploring the mechanism of ta_(3)N_(5)/KtaO_(3) photocatalyst for overall water splitting by first-principles calculations

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2021年第5期30卷 353-364页

作者： Yanxia ma Yumeng Fo Miaomiao Wang Xixi Liang Hao Dong Xin Zhou College of Environment and Chemical Engineering Dalian UniversityDalian 116622LiaoningChina School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 116029LiaoningChina

The rational fabrication of heterostructures is one of efficient strategies for improving photocatalytic performance of semiconductor *** recently,Domen and co-workers found that ta_(3)N_(5) single crystals grown on the surface of KtaO_(3) can accomplish photocatalytic overall water splitting for the first *** order to comprehend the underlying mechanism of this photocatalytic system,we have performed a systematic study based on density functional theory first-principles ***_(3)N_(5)(010)/KtaO_(3)(110)slab models have been built according to experimental observations by considering two common terminations of KtaO_(3)(110)surface,named as ta_(3)N_(5)/O_(2) and ta_(3)N_(5)/*** formations of interfacial bonds are thermodynamically stable,showing a covalent interaction between two components of a ***_(3)N_(5)/O_(2) has a higher mobility of photogenerated charge carriers and lower recombination rate of charge carriers than ta_(3)N_(5)/*** light absorption of heterostructures displays the feature of KtaO_(3) in the short wavelength region and the characteristic of ta_(3)N_(5) in the long wavelength *** calculated band offsets show that ta_(3)N_(5)/O_(2) and ta_(3)N_(5)/KtaO have distinct Type-II band alignments,with ta_(3)N_(5) as the accumulator of photoinduced electrons in the former and the collector of photogenerated holes in the latter,*** difference in charge density and electrostatic potential between two components acts as a driving force to promote the transfer of electrons and holes to different domains of the interface,which is beneficial to extend the lifetime of photoinduced *** results demonstrate that the function of ta_(3)N_(5) in ta_(3)N_(5)/KtaO_(3) photocatalytic system is determined by the termination property of KtaO_(3)(110)surface,which provides a likely reason of the observed photocatalytic activity of overall water splitting achieved by ta_(3)N_(5) synthesized by

关键词： ta3N5 Density functional theory calculations Separation of photogenerated carriers Semiconductor-based photocatalyst Overall water splitting

The effect of risk perception and COVID‑19 anxiety in pregnancy on decision‑making via the Internet and prenatal care quality:A cross‑sectional multivariate analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Nursing 2023年第1期5卷 27-32页

作者： Ayşe taştekin OUYABA Şehadet taŞKIN Obstetrics and Gynecology Nursing Faculty of Health SciencesAfyonkarahisar Health Sciences UniversityAfyonkarahisarTurkey Department of Nursing Balıklıgöl State HospitalSanliurfaTurkey

Background:Risk perception and COVID‑19 anxiety in pregnant women restrict access to health services,cause pregnant women to resort to alternative channels such as the Internet,and affect prenatal care quality(PCQ)***:The purpose of this study was to examine the effect of risk perception and COVID‑19 anxiety in pregnancy on decision‑making via the Internet(DMI)and PCQ with multivariate *** and Methods:This cross‑sectional study was conducted with 406 pregnant women selected using the convenience sampling method in a training and research hospital,in *** data were collected using the information form,the perception of pregnancy risk questionnaire,the Coronavirus Anxiety Scale,the DMI Scale,and the PCQ *** data obtained were subject to descriptive analysis and the multivariate analysis of ***:Approximately 24.9%of the pregnant women were found to have a high perception of risk and 18%had symptoms of COVID‑19 *** women with high COVID‑19 anxiety and a higher perception of risk perceived the Internet as less influential for decision‑making(Ptal health and resilience in pregnant women and to formulate appropriate intervention strategies.

关键词： COVID-19 anxiety decision-making via the Internet perception of risk pregnancy prenatal care quality

Co_3O_4 nanosheets:synthesis and catalytic application for CO oxidation at room temperature

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2014年第6期57卷 873-880页

作者： LV YongGe LI Yong ta Na SHEN WenJie State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences

Hexagonal β-Co(OH)2 nanosheets with edge length of 50 nm and thickness of 10 nm were hydrothermally synthesized with the aid of *** calcination at 350°C in air,the β-Co(OH)2 nanosheets was converted into Co3O4 nanosheets with a similar *** analyses during the calcination process identified that the β-Co(OH)2 precursor was initially dehydrated to HCoO2 and subsequently transferred into *** being applied to catalyze CO oxidation at room temperature,the Co3O4 nanosheets exhibited a higher activity than the conventional spherical *** was perhaps related to the partial exposure of the{112}planes over the Co3O4 *** porous structure generated during the calcination process also provided significant amounts of surface defects,which might contribute to the enhanced catalytic activity as well.

关键词： Co3O4 nanosheets CO oxidation morphology-dependence nanocatalysis

Effect of selected signals of interest on ultrasonic backscattering measurement in cancellous bones

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1310-1316页

作者： LIU ChengCheng HAN HaiJie ta DeAn WANG WeiQi Department of Electronic Engineering Fudan University

This study examined how the signals of interest （SOI） effect on the backscattering measurement numerically based on 3-D finite-difference time-domain （FDTD） method. High resolution microstructure mappings of bovine cancellous bones provided by micro-CT were used as the input geometry for simulations. Backscatter coefficient （BSC）, integrated backscatter coefficient （IBC） and apparent integrated backscatter （AIB） were calculated with changing the start （L1） and duration （L2） of the SOl. The results demonstrated that BSC and IBC decrease as L1 increases, and AIB decreases more rapidly as L1 increases. The backscattering parameters increase with fluctuations as a function of L2 when L2 is less than 6 mm. However, BSC and IBC change little as L2 continues to increase, while AIB slowly decreases as L2 continues to increase. The results showed how the selections of the SOI effect on the backscattering measurement. An explicit standard for SOl selection was proposed in this study and short L1 （about 1.5 mm） and appropriate L2 （6 mm-12 mm） were recommended for the calculations of backscattering parameters.

关键词： ultrasonic backscattering cancellous bone FDTD simulation signals of interest backscattering parameters

Nonfactorizable B→xcoK Decay and QCD Factorization

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第5X期48卷 885-890页

作者： MENG Ce GAO Ying-Jia CHAO Kuang-ta Department of Physics Peking University Beijing 100871 China China Center of Advanced Science and Technology (World Laboratory) Beijing 100080 China

We study the unexpectedly large rate for the factorization-forbidden decay B →xcoK within the QCD factorization approach. We use a non-zero gluon mass to regularize the infrared divergences in vertex corrections. The end-point singularities arising from spectator corrections are regularized and carefully estimated by the off-shellness of quarks. We find that the contributions arising from the vertex and leading-twist spectator corrections are numerically small, and the twist-3 spectator contribution with chiral enhancement and linear end-point singularity becomes dominant. With reasonable choices for the parameters, the branching ratio for B → XcoK decay is estimated to be in the range （2 ～ 4）× 10^-4, which is compatible with the Belle and BaBar data.

关键词： B meson decay QCD factorization charmonium

Joint spectrogram segmentation and ridge-extraction method for separating multimodal guided waves in long bones

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1317-1323页

作者： ZHANG ZhengGang XU KaiLiang ta DeAn WANG WeiQi Department of Electronic Engineering Fudan University

Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (JSSRE) method was proposed to separate multiple modes in long bones. First, the Gabor time-frequency transform was applied to obtain the spectrogram of multimodal signals. Then, a multi-class image segmentation algorithm was used to find the corresponding region of each mode in the spectrogram, including an improved watershed transform and a region growing procedure. Finally, the ridges were extracted and the time domain signals representing individual modes were reconstructed from these ridges in each region. The validations of this method were discussed by simulated multimodal signals with different signal-to-noise ratios (SNR). The correlation coefficients between the original signals without noise and the reconstructed signals were calculated to analyze the results quantitatively. The results showed that the extracted ridges were in good agreement with generated theoretical dispersion curves, and the reconstructed signals were highly related to the original signals, even under the SNR=3 dB situation.

关键词： multimodal guided waves long bone spectrogram segmentation

Location and Trajectory Identification from Microblogs

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2019年第4期34卷 727-746页

作者： Na ta Guo-Liang Li Jun Hu Jian-Hua Feng School of Journalism and Communication Renmin University of ChinaBeijing 100872China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China Airbnb Network(Beijing)Inc. Beijing 100020China

The rapid development of social networks has resulted in a proliferation of user-generated content(UGC),which can benefit many *** this paper,we study the problem of identifying a user's locations from microblogs,to facilitate effective location-based advertisement and *** the location information in a microblog is incomplete,we cannot get an accurate location from a local *** such,we propose a global location identification method,*** combines multiple microblogs of a user and utilizes them to identify the user's *** not only improves the quality of identifying a user's location but also supplements the location of a microblog so as to obtain an accurate location of a *** facilitate location identification,Glitter organizes points of interest(POIs)into a tree structure where leaf nodes are POIs and non-leaf nodes are segments of POIs,e.g.,countries,cities,and *** the tree structure,Glitter first extracts candidate locations from each microblog of a user which correspond to some tree *** Glitter aggregates these candidate locations and identifies top-κlocations of the *** the identified top-κuser locations,Glitter refines the candidate locations and computes top-κlocations of each *** achieve high recall,we enable fuzzy matching between locations and *** propose an incremental algorithm to support dynamic updates of *** also study how to identify users'trajectories based on the extracted *** propose an effective algorithm to extract high-quality *** results on real-world datasets show that our method achieves high quality and good performance,and scales well.

关键词： location identification microblog trajectory identification