检索结果-南通市图书馆

Photometric Properties and Stellar Parameters of the Rapidly Rotating Magnetic Early-B Star HD 345439

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2023年第1期23卷 18-31页

作者： Dong-xiang Shen Jin-Zhong Liu Chun-Hua Zhu Guo-Liang Lü Yu Zhang Cheng-Long Lü Hao-Zhi Wang Lei Li xi-zhen lu Jin-Long Yu Abdurepqet Rustem School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China xinjiang Astronomical Observatory National Astronomical ObservatoriesChinese Academy of SciencesUrumqi 830000China

We first present the multicolor photometry results of the rapidly rotating magnetic star HD 345439 using the Nanshan One-meter Wide-field *** the photometric observations,we derive a rotational period of 0.7699±0.0014 *** light curves of HD 345439 are dominated by the double asymmetric S-wave feature that arises from the magnetic *** behaviors are not observed in Sector 41 of the Transiting Exoplanet Survey *** evidence is found of the occurrence of centrifugal breakout events neither in the residual flux nor in the systematic variations at the extremum of the light *** on the hypothesis of the Rigidly Rotating Magnetosphere model,we restrict the magnetic obliquity angleβand the rotational inclination angle i so that they satisfy the approximate relationβ+i≈105°.The color excess,extinction,and luminosity are determined to be E_((B-V))=0.745±0.016 mag,A_(V)=2.31±0.05 mag,and log(L/L_(⊙))=3.82±0.1 dex,***,we derive the effective temperature as T_(eff)=22±1 kK and the surface gravity as log g=4.00±*** mass M=-7.24_(-1.24)^(+1.75)M_(⊙),radius R=4.44_(-1.93)^(+2.68)R_(⊙),and age τ_(age)=23.62_(-21.97)^(+4.24) Myr are estimated from the Hertzsprung-Russell diagram.

关键词： stars chemically peculiar-stars early-type-stars fundamental parameters-stars magnetic field

A promising approach for quantifying focal stroke modeling and assessing stroke progression:optical resolution photoacoustic microscopy photothrombosis

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第7期20卷 2029-2037页

作者： xiao Liang xingping Quan xiaorui Geng Yujing Huang Yonghua Zhao Lei xi zhen Yuan Ping Wang Bin Liu Faculty of Health Sciences University of MacaoMacao Special Administrative RegionChina Center for Cognitive and Brain Sciences University of MacaoMacao Special Administrative RegionChina Department of Biomedical Engineering Southern University of Science and TechnologyShenzhenGuangdong ProvinceChina State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoTaipaMacao Special Administrative RegionChina Department of Emergency Zhujiang HospitalSouthern Medical UniversityGuangzhouGuangdong ProvinceChina

To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral ***,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly *** this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed *** observed the molding process in mice of different ages and presented age-dependent vascular embolism ***,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a *** imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.

关键词： age-dependent cerebral cortex ischemic stroke mouse model optical coherence tomography angiography photoacoustic microscopy photothrombosis vascular imaging

Cross-subcarrier precoder design for massive MIMO-OFDM downlink with symplectic optimization

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2025年

作者： Yu-Xuan ZHANG An-An lu xiang-Gen xiA xi-Qi GAO National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories Department of Electrical and Computer Engineering University of Delaware

We propose a cross-subcarrier precoder design(CSPD) for massive multiple-input multiple-output(MIMO) orthogonal frequency division multiplexing(OFDM) downlink. This work aims to significantly improve the channel estimation and signal detection performance by enhancing the smoothness of the frequency domain effective channel. This is accomplished by designing a few vectors known as the transform domain precoding vectors(TDPVs), which are then transformed into the frequency domain to generate the precoders for a set of subcarriers. To combat the effect of channel aging, the TDPVs are optimized under imperfect channel state information(CSI). The optimal precoder structure is derived by maximizing an upper bound of the ergodic weighted sum-rate(WSR) and utilizing the a posteriori beam-based statistical channel model(BSCM). To avoid the large-dimensional matrix inversion, we propose an algorithm with symplectic optimization. Simulation results indicate that the proposed cross-subcarrier precoder design significantly outperforms conventional methods.

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

氨法脱硫试验研究分析

能源环境保护 2012年第4期26卷 27-30页

作者：高善彬鲁希振山东电力工程咨询院有限公司山东250013 大唐黄岛发电有限责任公司 266500

为研究氨法脱硫中气液比、吸收液pH值、吸收液浓度以及进口烟温对脱硫效果的影响，设计了一套实验台，以亚硫酸铵为吸收剂进行了实验研究和分析。结果表明．气液比越小，脱硫效率越高；吸收液pH值越大，脱硫效果越好；脱硫效率随吸收液... 详细信息

为研究氨法脱硫中气液比、吸收液pH值、吸收液浓度以及进口烟温对脱硫效果的影响，设计了一套实验台，以亚硫酸铵为吸收剂进行了实验研究和分析。结果表明．气液比越小，脱硫效率越高；吸收液pH值越大，脱硫效果越好；脱硫效率随吸收液浓度的增大先增加后减小，中间存在最大值；而温度对脱硫效果的影响不大。同时可根据此结果．气液比选择在0．2-0．25L／m^3范围，pH值选择为6～7．5范围，吸收液浓度为5．5％左右时．可使脱硫效果达到最好。

关键词：氨法脱硫亚硫酸铵影响因素脱硫效果

Orbitronics for energy-efficient magnetization switching

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2025年第1期68卷 398-399页

作者： Yuxuan YAO Daoqian ZHU Qingtao xiA Jianing LIANG Yuhao JIANG Zhiyang PENG Jiaxu LI Chen xiAO Renyou XU Wenwen WANG xiantao SHANG Shiyang lu Dapeng ZHU Hong-xi LIU Kaihua CAO Weisheng ZHAO Fert Beijing Institute School of Integrated Circuit Science and Engineering Beihang University National Key Lab of Spintronics Institute of International Innovation Beihang University Qingdao Research Institute Beihang University Truth Memory Corporation

Spin-orbit torque （SOT）,as a promising writing method for magnetic random-access memory （MRAM）,has garnered widespread interest for over a decade [1].Heavy metals,such as β-W,have been broadly adopted as spin current sources,but suffer from phase change at a limited thickness,resulting in a dramatic reduction of the charge-tospin conversion efficiency θSH[2].The thickness limitation leads to stringent etching conditions and large distribution among devices,posing challenges for simultaneously satisfying SOT efficiency,etching-stop margins,and back-end-ofline （BEOL） compatibility.

关键词：

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

FTIR-Q开关谐振腔理论

物理学报 1986年第4期 523-528页

作者：张镇西吕宝岭西北大学物理系

本文探讨了FTIR-Q开关谐振腔的基本理论,由于该腔用多光学元件组成,于是可用等效法,而不用普通的方法求解,我们利用矩阵光学和谐振腔衍射积分方程同时并用的方法,求出了理论解,获得该腔的菲涅耳数、衍射损耗、谐振频率和间隔等值,并与... 详细信息

本文探讨了FTIR-Q开关谐振腔的基本理论,由于该腔用多光学元件组成,于是可用等效法,而不用普通的方法求解,我们利用矩阵光学和谐振腔衍射积分方程同时并用的方法,求出了理论解,获得该腔的菲涅耳数、衍射损耗、谐振频率和间隔等值,并与平行平面腔的结果进行了比较,同时分析了球面腔的光学矩阵。

关键词：谐振腔衍射损耗平行平面菲涅耳数无源腔傍轴光线 FTIR-Q 球面镜球面反射镜

Learning to select pseudo labels: a semi-supervisedmethod for named entity recognition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2020年第6期21卷 903-916页

作者： zhen-zhen LI Da-wei FENG Dong-sheng LI xi-cheng lu College of Computer National University of Defense TechnologyChangsha 410073China

Deep learning models have achieved state-of-the-art performance in named entity recognition(NER);the good performance,however,relies heavily on substantial amounts of labeled *** some specific areas such as medical,financial,and military domains,labeled data is very scarce,while unlabeled data is readily *** studies have used unlabeled data to enrich word representations,but a large amount of entity information in unlabeled data is neglected,which may be beneficial to the NER *** this study,we propose a semi-supervised method for NER tasks,which learns to create high-quality labeled data by applying a pre-trained module to filter out erroneous pseudo *** labels are automatically generated for unlabeled data and used as if they were true *** semi-supervised framework includes three steps:constructing an optimal single neural model for a specific NER task,learning a module that evaluates pseudo labels,and creating new labeled data and improving the NER model *** results on two English NER tasks and one Chinese clinical NER task demonstrate that our method further improves the performance of the best single neural *** when we use only pre-trained static word embeddings and do not rely on any external knowledge,our method achieves comparable performance to those state-of-the-art models on the CoNLL-2003 and OntoNotes 5.0 English NER tasks.

关键词： Named entity recognition Unlabeled data Deep learning Semi-supervised method

A state-of-the-art review of the development of self-healing concrete for resilient infrastructure

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

Frontiers of Structural and Civil Engineering 2024年第2期18卷 151-169页

作者： Dong lu xi JIANG Yao ZHANG Shaowei ZHANG Guoyang lu zhen LENG Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China

The brittleness of cement composites makes cracks almost inevitable,producing a serious limitation on the lifespan,resilience,and safety of concrete *** address this brittleness,self-healing concrete has been developed for regaining its mechanical and durability properties after becoming cracked,thereby promising sustainable development of concrete *** paper provides a comprehensive review of the latest developments in self-healing *** begins by summarizing the methods used to evaluate the self-healing efficiency of ***,it compares strategies for achieving healing *** then discusses the typical approaches for developing self-healing ***,critical insights are proposed to guide future studies on the development of novel self-healing *** review will be useful for researchers and practitioners interested in the field of self-healing concrete and its potential to improve the durability,resilience,and safety of concrete infrastructure.

关键词： resilient infrastructure sustainable concrete self-healing cracks

NUMERICAL ANALYSIS OF THE UNSTEADY FORCE IN INSECT FORWARD FLIGHT

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

Journal of Hydrodynamics 2006年第2期18卷 143-147页

作者： ZHA xiong-quan lu xi-yun YIN xie-zhen Department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China

The objective of this study is to get into physical insights to the unsteady force and the relevant mechanisms in forward flight of insects. Unsteady force in the forward flight was studied, based on a virtual model problem of a foil with oscillating translation and rotation in a uniform flow, by solving the two-dimensional incompressible Navier-Stokes equations with a finite element method. The effects of typical parameters, including the advance ratio, the inclined angle of stroke plane, the stroke amplitude, and the amplitude of pitching angle of attack, on the forces and the flow structures were analyzed.

关键词： unsteady flow vortex dynamics thrust and lift,flapping motion biomechanics