检索结果-南通市图书馆

Journal of Rare Earths 2021年第6期39卷 696-702,I0004页

作者： Yi Sui xiaoyu liu Changsheng liu School of Materials Science and Engineering Northeastern UniversityShenyang 110004China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China

A novel Fe-Y composite oxide(Fe:Y-6.5) nanocluster was synthesized by self-assembly *** α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline with diameter around 10 nm are homogeneously assembled to form a cluster architecture which are constituted of Fe6.5Y composite oxide *** oxygen vacancies are introduced with cubic-Y_(2)O_(3),and the oxygen vacancies as Fe^(3+)-V_(0)-Y^(3+) between α-Fe_(2)O_(3) and cubic-Y_(2)O_(3) nanocrystalline are generated by self-assembly *** hysteresis loops recorded by vibrating sample magnetometry at 273 K display a ferromagnetic order,related to the fact that Fe^(3+)-V_(o)-Y^(3+) act as defect centers in the bound magnetic polaron model for Fe-Y composite oxide *** ferromagnetic prope rties are proportional to oxygen vacancy co ntents,and maximum magnetization(M_(m)) value of the nano-cluster reaches 5.14 A·m^(2)/g.

关键词： Room temperature ferromagnetism Fe-Y oxide nano-cluster Self-assembly Oxygen vacancy Rare earths

Multi-Label Image Classification Based on Object Detection and Dynamic Graph Convolutional Networks

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第9期80卷 4413-4432页

作者： xiaoyu liu Yong Hu School of Cyber Science and Engineering Sichuan UniversityChengdu610207China

Multi-label image classification is recognized as an important task within the field of computer vision,a discipline that has experienced a significant escalation in research endeavors in recent *** widespread adoption of convolutional neural networks(CNNs)has catalyzed the remarkable success of architectures such as ResNet-101 within the domain of image ***,inmulti-label image classification tasks,it is crucial to consider the correlation between *** order to improve the accuracy and performance of multi-label classification and fully combine visual and semantic features,many existing studies use graph convolutional networks(GCN)for *** detection and multi-label image classification exhibit a degree of conceptual overlap;however,the integration of these two tasks within a unified framework has been relatively underexplored in the existing *** this paper,we come up with Object-GCN framework,a model combining object detection network YOLOv5 and graph convolutional network,and we carry out a thorough experimental analysis using a range of well-established public *** designed framework Object-GCN achieves significantly better performance than existing studies in public datasets COCO2014,VOC2007,*** final results achieved are 86.9%,96.7%,and 96.3%mean Average Precision(mAP)across the three datasets.

关键词： Deep learning multi-label image recognition object detection graph convolution networks

Modulation of reactive oxygen species to enhance sonodynamic therapy

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

Particuology 2023年第4期75卷 199-216页

作者： xiaoyu liu Xueting Pan Chaohui Wang Huiyu liu Beijing Advanced Innovation Center for Soft Matter Science and Engineering State Key Laboratory of Organic-Inorganic CompositesBeijing Laboratory of Biomedical MaterialsBionanomaterials&Translational Engineering LaboratoryBeijing Key Laboratory of BioprocessBeijing University of Chemical TechnologyBeijing100029China

Reactive oxygen species(ROS),involving in many biological reactions,play an important role in disease *** the various ROS-based therapeutic modalities,sonodynamic therapy(SDT)stands out with its unique *** turn,the SDT efficacy is mainly dependent on the ROS levels in the disease ***,in recent years,researchers have extensively investigated SDT with high ROS generation *** this review,we focus on effective strategies to improve the therapeutic ef-ficiency of SDT by modulating ROS,overview the basic mechanisms of ROS generation by sonosensitizers,highlight the rational design of sonosensitizers,and summarize strategies to improve the SDT efficacy by modulating disease *** addition,multiple ROS synergistic treatment modalities and the prospect of SDT are *** believe that the understanding and exploration of SDT enhancement strategies will facilitate the clinical translation of SDT.

关键词： Reactive oxygen species Sonodynamic therapy Sonosensitizers Oxidative stress Combination therapy

A moving average Cholesky factor model in joint mean-covariance modeling for longitudinal data

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 Mathematics 2013年第11期56卷 2367-2380页

作者： liu xiaoyu ZHANG WeiPing Department of Statistics and Finance School of ManagementUniversity of Science and Technology of China

Modeling the mean and covariance simultaneously is a common strategy to efficiently estimate the mean parameters when applying generalized estimating equation techniques to longitudinal data. In this article, using generalized estimation equation techniques, we propose a new kind of regression models for parameterizing covariance structures. Using a novel Cholesky factor, the entries in this decomposition have moving average and log innovation interpretation and are modeled as the regression coefficients in both the mean and the linear functions of covariates. The resulting estimators for eovarianee are shown to be consistent and asymptotically normally distributed. Simulation studies and a real data analysis show that the proposed approach yields highly efficient estimators for the parameters in the mean, and provides parsimonious estimation for the covariance structure.

关键词： moving average factor generalized estimating equation longitudinal data modeling of mean andcovariance structures

Time and phase synchronization using clutter observations in airborne distributed coherent aperture radars

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第3期35卷 432-449页

作者： Jinming CHEN Tong WANG xiaoyu liu Jianxin WU National Laboratory of Radar Signal Processing Xidian UniversityXi’an 710071China School of Electronics and Communication Engineering Sun Yat-sen UniversityGuangzhou 510006China

Airborne Distributed Coherent Aperture Radar(ADCAR)is one of the most promising next-generation radars to significantly improve target detection and discrimination ***,time and phase synchronization among unit radars should be done before an ADCAR is intended to cohere on a potential *** address this problem,a time and phase synchronization technique using clutter observations is proposed in this *** returns from different azimuths and elevations on the surface of the earth are employed to calibrate system *** stages are mainly considered:a scene registration among range-Doppler units from different transmit/receive pairs is performed to enhance the clutter coherence in the first stage,followed by a joint estimation of those synchronization errors in the second *** relieve the computational burden,a novel Separable and Sequential Estimation(SSE)method is provided to separate the unknowns at the sacrifice of a range-Doppler ***,performance analyses including the clutter coherence ability,estimation lower bound,and signal coherence loss are also ***,simulation results indicate that ADCAR time and phase synchronization is realized by using our methods.

关键词： Airborne Distributed Coherent Aperture Radar(ADCAR) Clutter Maximum Likelihood Estimation(MLE) Signal coherence Time and phase synchronization

Progress in understanding epigenetic remodeling during induced pluripotency

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2015年第20期60卷 1713-1721页

作者： Rui Gao xiaoyu liu Shaorong Gao Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital School of Life Sciences and Technology Tongji University School of Life Sciences Tsinghua University National Institute of Biological Sciences

Over 50 years of efforts, cellular reprogram- ruing opens a new door for disease modeling and regen- erative medicine. Although induction of pluripotency by transcription factors has become common, only a small portion of basic mechanisms of epigenetic modifications during this process have been revealed. To clearly under- stand reprogramming and devise ways to promote full transition towards pluripotency, we must gain insight from comprehensive characterizations of cells at distinct repro- gramming stages, which involves gene expression profil- ing, chromatin state maps of key activating and repressive marks, and DNA modifications. Here, we review recent advances in epigenetic reprogramming to pluripotency with a focus on the principal molecular regulators and attach importance to the combination of high-throughput sequencing and systematic biology approaches in uncov- ering underlying molecular mechanisms of this unique platform in future researches.

关键词： Induced pluripotency Epigeneticreprogramming Histone modifications DNA modifications

基于PSM-DID方法的地方数字经济政策实施成效评估

在线全文

学校读者我要写书评

暂无评论

现代情报 2025年第1期45卷 33-45页

作者：李亚菲何文芊刘晓宇裴雷陈烨彭星南京大学信息管理学院江苏南京210023 南京大学数据智能与交叉创新实验室江苏南京210023 湖南省工业互联网发展研究中心湖南长沙410000 中国移动研究院北京100053

[目的/意义]数字经济政策已成为政府促进经济发展的重要政策工具,实证分析我国地方数字经济政策的实施成效,有助于推动地方经济实现高质量发展。[方法/过程]本文利用2010—2021年中国337个地级及以上城市的面板数据,采用PSM-DID方法检... 详细信息

[目的/意义]数字经济政策已成为政府促进经济发展的重要政策工具,实证分析我国地方数字经济政策的实施成效,有助于推动地方经济实现高质量发展。[方法/过程]本文利用2010—2021年中国337个地级及以上城市的面板数据,采用PSM-DID方法检验了地方数字经济政策对地区经济发展的影响。[结果/结论]地方数字经济政策能够显著促进地区经济增长,但其促进作用存在两年时滞;人口规模较大或行政等级较高的城市数字经济政策实施成效更显著;中西部地区数字经济政策对地区经济发展的促进作用超过了东部地区。

关键词：数字经济政策政策评估双重差分法倾向得分匹配地区经济增长

Electron vortex generations in photoionization of hydrogen atoms by circularly-polarized chirped attosecond pulses

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

Communications in Theoretical Physics 2024年第1期76卷 111-118页

作者： Bingshuang Zhang xiaoyu liu Fengzheng Zhu Liguang Jiao Aihua liu Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China College of Physics Jilin UniversityChangchun 130012China Helmholtz-Institut Jena D-07743 JenaGermany State Key Laboratory of Transient Optics and Photonics Chinese Academy of SciencesXi'an 710119China

By numerically solving the time-dependent Schr?dinger equation and employing the analytical perturbative model,we investigated the chirp-induced electron vortex in the photoionization of hydrogen atoms by a pair of counter-rotating circularly polarized chirped attosecond extremely ultraviolet *** demonstrated that single-photon ionization of hydrogen atoms generates photoelectron momentum distributions(PMDs)with distinct helical vortex structures either with or without a time delay between two counter-rotating circularly polarized laser *** structures are highly sensitive to both the time delay between the pulses and their chirp *** analytical model reveals that the splitting of vortex spirals is caused by the sign changing of the chirp-induced frequency-dependent time *** showed that to obtain the counterpart of the PMD under a pair of counter-rotating circularly polarized chirped pulses,both chirp parameters and ordering of pulses need to be reversed.

关键词： photoionization ultrafast processes ultrafast dynamics electron vortex

Biomechanism of resistance to retinal injury in woodpecker’s eyes

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2020年第4期63卷 592-598页

作者： Shan Lu Xingyu Fan Sijian liu xiaoyu liu Lizhen Wang Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical EngineeringBeihang UniversityBeijing 100191China Beijing Advanced Innovation Centre for Biomedical Engineering Beihang UniversityBeijing 102402China College of Bioengineering Chongqing UniversityChongqing 400044China

Retinal injury is the most common ocular impairment associated with shaken baby syndrome(SBS), which could lead to vision loss and blindness. However, a woodpecker does not develop retinal hemorrhages or detachment even at a high acceleration of 1,000×g during pecking. To understand the mechanism of retinal injury and its resistance strategy, we put insight into the special ability of the woodpecker to protect the retina against damage under acceleration–deceleration impact. In this study, the structural and mechanical differences on the eyes of the woodpecker and human were analyzed quantitatively based on anatomical observation. We developed finite element eye models of the woodpecker and human to evaluate the dynamic response of the retina to the shaking load obtained from experimental data. Moreover, several structural parameters and mechanical conditions were exchanged between the woodpecker and human to evaluate their effects on retinal injury in SBS. The simulation results indicated that scleral ossification, lack of vitreoretinal attachment, and rotational acceleration–deceleration impact loading in a woodpecker contribute to the resistance to retinal injuries during pecking. The above mentioned special physical structures and mechanical behavior can distribute the high strain in the posterior segment of the woodpecker’s retina, which decrease the risk of retinal injury to SBS.

关键词： shaken baby syndrome woodpecker retinal injury numerical simulations

Insights into epigenetic patterns in mammalian early embryos

在线全文

学校读者我要写书评

暂无评论

Protein & Cell 2021年第1期12卷 7-28页

作者： Ruimin Xu Chong Li xiaoyu liu Shaorong Gao Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital Shanghai Key Laboratory of Signaling and Disease ResearchFrontier Science Center for Stem Cell ResearchSchool of Life Sciences and TechnologyTongji UniversityShanghai 200092China Institute for Regenerative Medicine Shanghai East HospitalShanghai Key Laboratory of Signaling and Disease ResearchFrontier Science Center for Stem Cell ResearchSchool of Life Sciences and TechnologyTongji UniversityShanghai 200092China Tsingtao Advanced Research Institute Tongji UniversityQingdao 266071China

Mammalian fertilization begins with the fusion of two specialized gametes,followed by major epigenetic remodeling leading to the formation of a totipotent *** the development of the pre-implantation embryo,precise reprogramming progress is a prerequisite for avoiding developmental defects or embryonic lethality,but the underlying molecular mechanisms remain *** the past few years,unprecedented breakthroughs have been made in mapping the regulatory network of dynamic epigenomes during mammalian early embryo development,taking advantage of multiple advances and innovations in low-input genome-wide chromatin analysis *** aim of this review is to highlight the most recent progress in understanding the mechanisms of epigenetic remodeling during early embryogenesis in mammals,including DNA methylation,histone modifications,chromatin accessibility and 3D chromatin organization.

关键词： epigenetic reprogramming DNA methylation histone modifications early embryo development