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Primordial magnetic fields from gravitationally coupled electrodynamics in nonsingular bounce cosmology

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 43-50页

作者： JieWen Chen ChongHuan li yubin li Mian Zhu CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China School of Astronomy and Space Science University of Science and Technology of China Department of Physics and Astronomy University of Utah Department of Physics The Chinese University of Hong Kong School for Gifted Young University of Science and Technology of China

We in this paper study a class of mechanism of the production of the primordial magnetic field(PMF) in the non-singular bouncing cosmology, through the coupling of the electromagnetic field to gravity. We adopt an electrodynamic model with a coupling coefficient as a function of the scale factor a, i.e., f = 1 +(a/a?)^(-n), with a? and n > 0 being constants. With analytical calculations, we find that this model can yield a blue tilted power spectrum of PMF on large scales from 1 Mpc to the Hubble length if the bounce scenario has experienced a contracting phase with an equation-of-state parameter larger than-1/3. Furthermore, in order to satisfy the constraints of observational data, the present mechanism favors the so-called ekpyrotic-bounce paradigm. The back-reaction of the energy density of PMF at the bouncing point can lead to additional theoretical constraints on the underlying bouncing paradigm.

关键词：宇宙论非退化磁场重力 PMF 模特儿 Mpc 反应能

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基于低秩学习的阿尔茨海默病诊断方法

现代电子技术 2024年第11期47卷 99-104页

作者：张军李钰彬东华理工大学信息工程学院江西南昌330013

阿尔茨海默病是老年痴呆症中最普遍的一种,目前大量国内外老年人的生活受其困扰。然而,目前阿尔茨海默病在我国仍然处于就诊率低、误诊率高、治疗率低的局面,因此亟需探索阿尔茨海默病的早期诊断方案,以及时发现潜在病患并进行干预治疗... 详细信息

阿尔茨海默病是老年痴呆症中最普遍的一种,目前大量国内外老年人的生活受其困扰。然而,目前阿尔茨海默病在我国仍然处于就诊率低、误诊率高、治疗率低的局面,因此亟需探索阿尔茨海默病的早期诊断方案,以及时发现潜在病患并进行干预治疗。当前,计算机辅助诊断十分流行,能帮助医生快速、高效地进行疾病诊断。因此,文中提出基于低秩学习的阿尔茨海默病诊断方法(LRL)。该方法利用MRI图像数据提取多模板特征并进行融合;然后针对MRI数据样本数量少、特征维度高的特点,采用低秩学习方法进行特征选择,得到最具代表性的特征子集;最后将选择后的特征输入到支持向量机(SVM)分类器,执行三分类和四分类任务。实验结果表明,提出的LRL模型优于其他几种经典的特征选择方法。在两个主要评价指标准确率ACC和F1上,LRL模型在三分类实验中分别达到了74.94%和75.80%,在四分类实验中分别达到了63.88%和59.99%。

关键词：阿尔茨海默病 MRI图像低秩学习支持向量机多分类计算机辅助诊断

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On the surface fluxes characteristics and roughness lengths at Zhongshan station,Antarctica

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International Journal of Digital Earth 2019年第8期12卷 878-892页

作者： Changwei liu yubin li Qinghua Yang linlin Wang Xianqiao Wang Shimin li Zhiqiu Gao Key Laboratory of Meteorological Disaster of Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters School of Geography and Remote SensingNanjing University of Information Science and TechnologyNanjingChina Key Laboratory of Research on Marine Hazards Forecasting National Marine Environment Forecasting CenterBeijingPeople’s Republic of China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingPeople’s Republic of China

Over Antarctica,surface fluxes play an important role in the local atmospheric dynamical processes.To reveal the surface fluxes characteristics and aerodynamic and thermal roughness lengths over Zhongshan station,Antarctica,this paper analyzes the data observed at the station during 3 March 2008 through 15 February 2009.It is found that easterlies dominated this site throughout the whole year,with a maximum(average)speed of 25(5.6)m s−1 at 3.9 m height,and the annual maximum(minimum)surface temperature reached 291.05(230.05)K,while the annual maximum(minimum)air-specific humidity was 4.1(0.05)g/kg at 3.9 m height.The maximum(minimum)values of seasonal mean temperature,humidity,each radiation components,sensible and latent heat flux occurred in summer(winter),while for the seasonal averaged wind speed andτthe minimums(maximums)appeared in summer(autumn).After comparing with a partially linear regression method for aerodynamic roughness length and four previous equations that derive thermal roughness length from surface Reynolds number,constant values of aerodynamic roughness length as 3.6×10^(−3)m and thermal roughness length as 1.2×10^(−4)m at this site were validated by using the other three level observations and suggested for future studies.

关键词： Antarctica Zhongshan station turbulent momentum flux sensible heat flux aerodynamic roughness length thermal roughness length

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基于资源感知的分布式爬虫任务调度方法

现代电子技术 2024年第9期47卷 86-90页

作者：张军魏继桢李钰彬东华理工大学信息工程学院江西南昌330013

文中致力于开发一种基于资源感知的分布式爬虫任务调度方法,以优化分布式环境中各节点的系统资源利用,提升爬虫任务的执行效率。该方法通过引入资源感知调度算法和节点优先级管理,实现对节点中CPU、内存、网络等资源的监测,以便均衡调... 详细信息

文中致力于开发一种基于资源感知的分布式爬虫任务调度方法,以优化分布式环境中各节点的系统资源利用,提升爬虫任务的执行效率。该方法通过引入资源感知调度算法和节点优先级管理,实现对节点中CPU、内存、网络等资源的监测,以便均衡调度爬虫任务,即确保爬虫任务在资源利用率较低的节点上执行,从而有效减轻各个节点之间资源过度占用和不均衡问题。另外,该方法引入的Flask提高了可扩展性,实现了可视化爬虫监控平台。实验结果表明,文中提出的方法在提高爬虫任务执行效率和适应性方面取得了显著效果,为分布式爬虫系统的进一步优化提供了有益指导。

关键词：分布式爬虫任务调度资源感知 Flask 数据采集资源利用率

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地铁专用无线通信系统扩容改造方案

移动信息 2024年第3期46卷 31-33页

作者：李玉斌南京地铁运营有限责任公司南京211135

南京地铁1、10号线专用无线通信系统采用空中客车TETRA数字集群系统,中央共用核心交换机,随着1号线、10号线的逐渐延伸,需进行系统扩容改造。文中探讨了专用无线通信系统的扩容改造方法,详细分析了改造的具体步骤,以尽可能减少改造业务... 详细信息

南京地铁1、10号线专用无线通信系统采用空中客车TETRA数字集群系统,中央共用核心交换机,随着1号线、10号线的逐渐延伸,需进行系统扩容改造。文中探讨了专用无线通信系统的扩容改造方法,详细分析了改造的具体步骤,以尽可能减少改造业务对现场运营的影响、降低现场改造实施及操作的风险性。

关键词：南京地铁专用无线通信数字集群扩容改造

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地铁专用通信电源UPS构成及典型故障分析

通信电源技术 2024年第5期41卷 80-84页

作者：李玉斌南京地铁运营有限责任公司江苏南京211135

地铁专用通信电源系统是地铁通信系统的一个重要子系统,不间断电源(Uninterruptible Power Supply,UPS)是地铁通信电源系统的重要组成设备。阐述地铁通信电源UPS各个部件构成,包括输入单元、整流器、逆变器、蓄电池组以及静态开关等,介... 详细信息

地铁专用通信电源系统是地铁通信系统的一个重要子系统,不间断电源(Uninterruptible Power Supply,UPS)是地铁通信电源系统的重要组成设备。阐述地铁通信电源UPS各个部件构成,包括输入单元、整流器、逆变器、蓄电池组以及静态开关等,介绍各个部件工作原理和地铁通信UPS采用的在线工作方式,并分析单机4种供电工作模式和并机5种供电工作模式的原理。最后,列举实际维护过程中发生的4件UPS故障,通过原因分析及处理过程描述,帮助提高UPS维护的实践能力。

关键词：地铁专用通信通信电源不间断电源(UPS)

Spatially Resolved Properties of the GW170817 Host Galaxy

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Research in Astronomy and Astrophysics 2023年第7期23卷 80-95页

作者： yubin li Jirong Mao Jianbo Qin Xianzhong Zheng Fengshan liu Yinghe Zhao Xiaohong Zhao Yunnan Observatories Chinese Academy of SciencesKunming 650011China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

GW170817 is the unique gravitational-wave(GW)event associated with the electromagnetic(EM)counterpart GRB 170817A.NGC 4993 is identified as the host galaxy of GW170817/GRB 170817A.In this paper,we focus on the spatially resolved properties of NGC 4993.We present the photometric results from the comprehensive data analysis of the high spatial-resolution images in the different optical bands.The morphological analysis reveals that NGC 4993 is a typical early-type galaxy without significant remnants of a major galaxy merger.The spatially resolved stellar population properties of NGC 4993 suggest that the galaxy center has passive evolution with the outskirt formed by gas accretion.We derive the merging rate of the compact object per galaxy by a co-evolution scenario of a supermassive black hole and its host galaxy.If the galaxy formation is at redshift 1.0,the merging rate per galaxy is from 3.2×10^(-4)to 7.7×10^(-5)within the merging decay time from 1.0 to 5.0 Gyr.The results provide vital information for ongoing GW EM counterpart detections.The Hubble space telescope data analysis presented in this paper can be also applied to Chinese Space Station Telescope research in the future.

关键词： galaxies:evolution (stars:)binaries:general gravitational waves

OsABA8ox2, an ABA catabolic gene, suppresses root elongation of rice seedlings and contributes to drought response

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The Crop Journal 2020年第3期8卷 480-491页

作者： Yan Zhang Xiaoping Wang Yanzhong Luo Lan Zhang Yuan Yao Lu Han Zhenhua Chen Lei Wang yubin li Biotechnology Research Institute Chinese Academy of Agricultural SciencesBeijing 100081China College of life Science and Technology Harbin Normal UniversityHarbin 150025HeilongjiangChina

In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.

关键词： ABA suppresses root elongation of rice seedlings and contributes to drought response OsABA8ox2 an ABA catabolic gene

稻麦轮作农田近地层湍流通量计算方案对比研究

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气象科技 2024年第3期52卷 434-445页

作者：刘昕晔李煜斌南京信息工程大学大气物理学院南京210044

稻麦轮作农田是我国典型农田类型,其模拟效果对我国农田气候模拟具有重要参考价值。气候中尺度模拟结果对近地层通量极为敏感,选择合适的通量计算方案对模拟效果至关重要。因此,对比分析稻麦轮作农田下不同的通量计算方案具有重要意义... 详细信息

稻麦轮作农田是我国典型农田类型,其模拟效果对我国农田气候模拟具有重要参考价值。气候中尺度模拟结果对近地层通量极为敏感,选择合适的通量计算方案对模拟效果至关重要。因此,对比分析稻麦轮作农田下不同的通量计算方案具有重要意义。本文选取了8种具有代表性的近地层湍流通量计算方案,采用寿县国家气候观象台实测资料对比分析了各方案在稻麦轮作农田的计算特征和差异。结果表明,在不同稳定度和不同风速情况下,各方案的误差特征各异。本文基于归一化标准差综合评价了各方案的准确度,总体而言,所有方案的动量通量总体平均归一化平均差为0.536,其中SS14(Sharan和Srivastava, 2014年)方案最大为0.575,SS20(Sharan和Srivastava等,2020年)方案最小为0.517;所有方案的感热通量总体平均归一化标准差为0.638,其中GLGS20(Gryanik等,2020年)方案最大为0.871,SS14方案最小为0.476。此外,本研究还给出了稻麦轮作农田不同稳定层结和不同风速情况下各通量计算方案的误差特征。本文的研究结论,可为准确计算近地层湍流通量提供支撑。

关键词：稻麦轮作农田下垫面近地层湍流通量动力学粗糙度 M-O相似理论稳定度修正函数