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一类具有时滞的Schnakenberg模型的Hopf分支及稳定性

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兰州文理学院学报（自然科学版） 2024年第3期38卷 1-8页

作者：王佳月袁海龙陕西科技大学数学与数据科学学院陕西西安710021 西安交通大学数学与统计学院陕西西安710049

研究了一类在齐次Neumann边界条件下具有时滞的Schnakenberg模型.首先,以时滞为分支参数,分析了时滞对该系统正平衡点稳定性的影响,并给出了Hopf分支的存在条件.其次,运用中心流形定理和规范型理论,得到Hopf分支方向和分支周期解的稳定... 详细信息

研究了一类在齐次Neumann边界条件下具有时滞的Schnakenberg模型.首先,以时滞为分支参数,分析了时滞对该系统正平衡点稳定性的影响,并给出了Hopf分支的存在条件.其次,运用中心流形定理和规范型理论,得到Hopf分支方向和分支周期解的稳定性.最后,利用Matlab软件进行数值模拟,验证结论的正确性,得出时滞会使稳定的系统变得不稳定,并产生Hopf分支.

关键词：扩散时滞稳定性 Hopf分支 Schnakenberg模型

维普期刊数据库博看期刊

基于距离泛化的二分图(α,β)-core高效分解算法

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计算机科学 2024年第11期51卷 95-102页

作者：张毅豪华征宇袁龙张帆王凯陈紫南京理工大学计算机科学与工程学院广州大学网络空间安全学院上海交通大学安泰经济与管理学院南京航空航天大学计算机科学与技术学院

(α,β)-core分解作为图数据管理与分析研究中的热点问题，已经被广泛应用于电商欺诈检测和兴趣群组推荐等实际场景中。然而现有(α,β)-core模型在构建时仅考虑顶点距离为1的邻居，难以刻画出二部图社区中的细粒度信息。针对此问题，... 详细信息

(α,β)-core分解作为图数据管理与分析研究中的热点问题，已经被广泛应用于电商欺诈检测和兴趣群组推荐等实际场景中。然而现有(α,β)-core模型在构建时仅考虑顶点距离为1的邻居，难以刻画出二部图社区中的细粒度信息。针对此问题，提出了基于距离泛化的(α,β,h)-core模型，即由二部图中两个不相交的顶点集构成一个最大子图，满足一个集合中的任何一个顶点至少有α个与它的距离不大于h的邻居顶点，另一个集合中的任何一个顶点至少有β个与它的距离不大于h的邻居顶点。通过引入距离为h的邻居，解决了(α,β)-core模型细粒度刻画能力不足的问题。由于新模型需要考虑距离不大于h的邻居，因此(α,β,h)-core分解变得更为困难。为此，提出了基于计算共享的分解策略，据此设计了高效的(α,β,h)-core分解算法，并分析了算法性能。考虑到确定距离不大于h的邻居顶点非常耗时，还提出一种(α,β,h)-core下界以减少重复计算距离不大于h的邻居顶点，进一步提高计算效率。在8个真实图数据上的对比实验结果验证了新模型的有效性和算法的高效性。

关键词：二部图 (α,β,h)-core分解高效算法

Improved Energy Conversion Efficiency of ZnO/Polythiophene Solar Cell in Ga-Doped ZnO Nanorod Array Photoanode

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Chemical Research in Chinese Universities 2016年第6期32卷 979-984页

作者： WU Jie LIU Huanhuan yuan long HOU Changmin State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China

We reported the fabrication and doping effect of Ga-doped ZnO nanorods/electropolymerized polythio-phene（e-PT） hybrid photovoltaic（h-PV） devices. Ga-Doped ZnO nanorod array photoanode devices were fabricatedvia hydrothermally growing nanorods on sol-gel spin-coating ZnO seed layer, and then the nanorod array was im-mersed into a thiophene solution to yield a thin polythiophene film by electrochemically polymerization. Afterwards,a thin layer of A1 was deposited on the surface of polythiophene to make an electrode for photovoltaic *** ZnO nanorods with different Ga-doping contents were characterized by means of X-ray diffraction（XRD）, scan-ning electron micrograph（SEM） and X-ray photoelectron spectroscopy（XPS）. Photovoltaic J-V characterization wasperformed on the e-PT/ZnO bilayer and bulk heterojunction（BHJ） devices. Though the unsubstituted polythiophene isnot an ideal polymer material for solar cells with high power conversion efficiency, it is a sound model for the studyon the effect of dopant in hybrid materials. The results indicate that doping Ga can substantially improve the powerconversion efficiency of the ZnO-polythiophene solar cell.

关键词： Solar cell Energy conversion Ga-Doped ZnO

Maser Emission of Relativistic Electrons Spiralling and Drifting in Curved Magnetic Fields

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 304-316页

作者： Jiong Liu Ye-Fei yuan Xiao-long Deng Center for Astrophysics University of Science and Technology of China Hefei 230026

Synchro-curvature radiation describes the emission from a relativistic charged particle which is moving and spiralling in a curved magnetic field. We investigate the maser emission for synchro-curvature radiation including drift of the guiding center of the radiating electron. It is shown that under some conditions the absorption coefficient can be negative, so maser can happen. These conditions are different from those needed for maser emission of curvature radiation including drift of the charged particles. We point out that our results, including the emissivity, can reduce to these of curvature radiation. Previously it was found that synchro-curvature radiation can not generate maser in vacuum, but we argue that synchrocurvature radiation including drift can generate maser even in vacuum. We discuss the possibilities of the potential applications of the synchro-curvature maser in modeling gamma ray bursts and pulsars.

关键词： masers - plasmas - radiation mechanisms non-thermal

Nd3-xAExFe5O12： Hydrothermal Synthesis, Structure and Magnetic Properties

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Chemical Research in Chinese Universities 2017年第6期33卷 869-875页

作者： WU Jie yuan long WANG Shan HOU Changmin State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China Department of Materials Science and Engineering Jilin Institute of Chemical Technology Jilin 132022 P. R. China

Rare-earth ferrite garnet is one of the most important materials applied in microwave transducer and in- frared magneto-optical devices, etc. Nd3-xAExFe5O12（AE=Ca, Sr） crystals, which have cubic structure with the space group ofIa-3 d and lattice constants over 1.26 nm, were prepared via the mild hydrothermal method. The structural, morhpology and magnetic properties were characterized by means of powder X-ray diffraction, scanning electronic microscopy, as well as vibrating sample magnetometer and M6ssbauer spectroscopy, respectively. M6ssbaner spectroscopy demonstrates the coexistence of Sr2＋, Ca2＋ and Nd3＋ at the C sites of the dodecahedrons for different substituted garnets. The crystal shape is dodecahedron, and the particle sizes are decreased with increasing the Ca and Sr doping concentrations. By recording the magnetic hysteresis loops and M-T curves at different temperatures, it can be seen that with the increasing x, the saturation magnetization values decrease while the coercive forces increase under the condition of high temperatures.

关键词： Garnet structure Magnetic property M6ssbauer spectrum

Hydrothermal Synthesis and Magnetic Properties of SmCr0.5M0.5O3（M=Fe and Mn） Micro-plates

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Chemical Research in Chinese Universities 2018年第1期34卷 1-7页

作者： ZHANG Jiaqi WANG Shan yuan long HOU Changmin State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China Department of Materials Science and Engineering Jilin Institute of Chemical Technology Jilin 132022 P. R. China

Nanostructured B-site Fe and Mn doped SmCrO3 was prepared by mild hydrothermal growth. The as-prepared crystals are mainly micrometer-scale plates, ranging from rhombus（SmCr0.5Fe0.5O3） to elongated hexagonal（SmCr0.5Mn0.5O3）, and finally to well-edged rectangular（SmCr0.17Mn0.5Fe0.33O3） plates. Fe and Mn doped SmCrO3 crystals are indexed into Pbnm space group. The cell parameters of SmCr0.5Fe0.5O3 are slightly smaller than that of pristine SmCrO3. Binding energy analysis of Cr, Mn and Fe in SmCr0.17TMn0.5Fe0.33O3 sample indicates that they all possess ＋3 oxidation states. Temperature dependent magnetization of the as-prepared samples presents obviously stronger ferromagnetic interactions than the undoped counterparts. This work represents a remarkable development for hydrothelmal synthesis into fabricating perovskite oxide crystals with uniform distribution of doping ions.

关键词： Hydrothermal synthesis Perovskite structure B-Site ordering Magnetic property

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电力机车电气屏柜端子排模块设计与研究

电力机车与城轨车辆 2024年第5期47卷 110-113页

作者：袁新辉龙源刘家奇尹菲周浩宇中车株洲电力机车有限公司湖南株洲412001

为提升电气屏柜模块化设计理念以及产品竞争力,文章从电力机车电气原理着手,结合电气屏柜工程化设计要求,阐述了电气屏柜端子排模块设计的原理与思路,通过标准的端子排模块设计与应用,将整车众多电气部件进行合理的电气连接,最大限度地... 详细信息

为提升电气屏柜模块化设计理念以及产品竞争力,文章从电力机车电气原理着手,结合电气屏柜工程化设计要求,阐述了电气屏柜端子排模块设计的原理与思路,通过标准的端子排模块设计与应用,将整车众多电气部件进行合理的电气连接,最大限度地减少电气屏柜中的重复走线,降低了电气屏柜成本,提升了产品颜值,实现了电气屏柜端子排的模块化设计。

关键词：电力机车电气屏柜端子排模块设计

原发性肝癌TACE术后医院感染临床特征及microRNA的预测价值

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中华医院感染学杂志 2024年第9期34卷 1362-1365页

作者：张超赵婷戴钰辉袁泽龙吴汝江河北北方学院附属第一医院介入科河北张家口075000 河北北方学院附属第一医院国际医疗部河北张家口075000

目的探讨原发性肝癌肝动脉栓塞介入化疗(TACE)术后医院感染的特点及与血清微小核糖核酸(miR)的关系。方法选取2019年1月-2023年4月于河北北方学院附属第一医院接受TACE手术治疗的648例原发性肝癌患者,根据是否发生医院感染分为感染组51... 详细信息

目的探讨原发性肝癌肝动脉栓塞介入化疗(TACE)术后医院感染的特点及与血清微小核糖核酸(miR)的关系。方法选取2019年1月-2023年4月于河北北方学院附属第一医院接受TACE手术治疗的648例原发性肝癌患者,根据是否发生医院感染分为感染组51例和未感染组597例,比较两组患者临床特点和血清miR-200a、miR-15a及miR-221水平,绘制受试者工作特征(ROC)曲线分析血清miR-200a、miR-15a及miR-221对原发性肝癌TACE术后医院感染的预测价值。结果感染组合并糖尿病、有脾脏栓塞、有侵入性操作患者占比高于未感染组(P<0.05);感染组血清miR-200a、miR-15a水平低于未感染组(P<0.05),血清miR-221水平高于未感染组(P<0.05);ROC曲线分析结果显示,血清miR-200a、miR-15a及miR-221联合检测预测原发性肝癌TACE术后医院感染的曲线下面积(AUC)值为0.917,高于单独预测(P<0.05)。结论血清miR-200a、miR-15a在原发性肝癌TACE术后医院感染患者中呈低表达,而血清miR-221呈高表达,且合并糖尿病、有脾脏栓塞、有侵入性操作与原发性肝癌TACE术后医院感染有关。

关键词：原发性肝癌肝动脉栓塞介入化疗医院感染临床特征微小核糖核酸预测价值

Measurements and analysis of water content in winter wheat leaf based on terahertz spectroscopy

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International Journal of Agricultural and Biological Engineering 2018年第3期11卷 178-182页

作者： Bin Li yuan long Hao Yang Beijing Research Center for Information Technology in Agriculture Beijing 100097China Beijing Key Laboratory of Digital Plant Beijing 100097China Beijing Research Center of Intelligent Equipment for Agriculture Beijing 100097China Key Laboratory of Quantitative Remote Sensing in Agriculture of Ministry of Agriculture Beijing 100097China

Wheat is a major grain crop in *** is one of the most important factors which influence the lifecycle and yield of *** is of great significance to study the water content at the key stages of wheat growth in order to make irrigation decision to raise its *** Terahertz(THz)spectroscopy is a brand new sensing technology and sensitive to water absorption,the relationship between terahertz spectra and water content in winter wheat leaf was investigated and a preliminary result was presented in this *** winter wheat leaves samples with diverse range of water content(42.8%-72.5%)were *** Terahertz time domain spectra(THz-TDS)were first obtained and then transformed into Frequency-domain amplitude with the Fast Fourier Transformation(FFT)*** absorption and refractive index spectra were then *** spectra were linearly fitted to obtain the slope and intercept used for building a calibration *** partial least squares(PLS)method and linear regression were employed to establish models to determine leaf water content in the winter *** predicted correlation coefficient and the root mean square error of the optimal model established with the Frequency-domain amplitude parameter at 0.3 THz by linear regression were 0.812%and 4.4%,*** results showed that terahertz spectroscopy performed well in water content prediction and could be an effective and potential method for leaf water content measurement in winter wheat.

关键词： terahertz spectroscopy winter wheat gravimetric water content(GWC) partial least squares method