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The kinematics of an untwisting solar jet in a polar coronal hole observed by SDO/AIA

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Research in Astronomy and Astrophysics 2012年第5期12卷 573-583页

作者： Hua-Dong Chen Jun Zhang Su-Li ma College of Science China University of Petroleum Qingdao 266555 China Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Harvard-Smithsonian Center for Astrophysics MA 02138 U 5A

Using the multi-wavelength data from the Atmospheric Imaging Assembly （AIA） onboard the Solar Dynamics Observatory （SDO） spacecraft, we study a jet occurring in a coronal hole near the northern pole of the Sun. The jet presented distinct upward helical motion during ejection. By tracking six identified moving features （MFs） in the jet, we found that the plasma moved at an approximately constant speed along the jet＇s axis. Meanwhile, the MFs made a circular motion in the plane transverse to the axis. Inferred from linear and trigonometric fittings to the axial and transverse heights of the six tracks, the mean values of the axial velocities, transverse velocities, angular speeds, rotation periods, and rotation radii of the jet are 114 km s-1, 136 km s-1, 0.81° s-1, 452 s and 9.8 × 10^3 km respectively. As the MFs rose, the jet width at the corresponding height increased. For the first time, we derived the height variation of the longitudinal magnetic field strength in the jet from the assumption of magnetic flux conservation. Our results indicate that at heights of 1 × 10^4 -7 × 10^4 km from the base of the jet, the flux density in the jet decreases from about 15 to 3 G as a function of B = 0.5（R/R） - 1）-0.84 （G）. A comparison was made with other results in previous studies.

关键词： Sun activity -- Sun chromosphere -- Sun magnetic fields -- Sun flares -- Sun rotation

Dynamics of electric activities in neuron and neurons of network induced by autapses

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Science China(Technological Sciences) 2014年第5期57卷 936-946页

作者： QIN HuiXin ma Jun JIN Wuyin WANG ChunNi Department of Physics Lanzhou University of Technology College of Mechano-Electronic Engineering Lanzhou University of Technology

The effect of autapse on adjusting the membrane of potentials of neuron is described by imposing a time-delayed feedback on the membrane of neuron in a close loop type,and the Hindmarsh-rose(HR)neuron under autapse is ***,the electric activity of single HR neuron under electric autapse and chemical autapse is *** is found that quiescent neuron is activated due to appropriate time delay and feedback gain in the autapse,and the autapse plays an important role in waking up *** parameter region for periodic,chaotic activity of neuron under autapse is calculated in a numerical way,and transition from spiking to bursting is observed by increasing the feedback gain and time delay ***,the collective electric activities of neurons in a ring network is investigated and abundant electric activities are observed due to the competition between the autapse and the time-delayed coupling between adjacent neurons in the network,and time delay in coupling between neurons also plays an important role in enhancing synchronization in the network.

关键词： time delay bifurcation Lyapunov exponent neuron network

Autapse-induced target wave, spiral wave in regular network of neurons

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Science China(Physics,Mechanics & Astronomy) 2014年第10期57卷 1918-1926页

作者： QIN HuiXin ma Jun WANG ChunNi CHU RunTong Department of Physics Lanzhou University of Technology

Autapse is a type of synapse that connects axon and dendrites of the same neuron, and the effect is often detected by close-loop feedback in axonal action potentials to the owned dendritic tree. An artificial autapse was introduced into the Hindmarsh-rose neuron model, and a regular network was designed to detect the regular pattern formation induced by autapse. It was found that target wave emerged in the network even when only a single autapse was considered. By increasing the(autapse density) number of neurons with autapse, for example, a regular area(2×2, 3×3, 4×4, 5×5 neurons) under autapse induced target wave by selecting the feedback gain and time-delay in autapse. Spiral waves were also observed under optimized feedback gain and time delay in autapses because of coherence-like resonance in the network induced by some electric autapses connected to some neurons. This confirmed that the electric autapse has a critical role in exciting and regulating the collective behaviors of neurons by generating stable regular waves(target waves, spiral waves) in the network. The wave length of the induced travelling wave(target wave, spiral wave), because of local effect of autapse, was also calculated to understand the waveprofile in the network of neurons.

关键词： target wave spiral wave network autapse time-delay memory

Carbon-supported layered double hydroxide nanodots for efficient oxygen evolution: Active site identification and activity enhancement

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Nano Research 2021年第9期14卷 3329-3336页

作者： Shenlong Zhao Detao Zhang Shuai Jiang yanglansen Cui Haijing Li Juncai Dong Zhirun Xie Da-Wei Wang rose Amal Zhenhai Xia Liming Dai Australian Carbon materials Centre(A-CMC) School of Chemical EngineeringThe University of New South WalesSydneyNSW 2052Australia Center of Advanced Science and Engineering for Carbon(Case4Carbon) Department of Macromolecular Science and EngineeringCase Western Reserve University(CWRU)10900 Euclid AvenueClevelandOH 44106USA School of Chemical and Biomolecular Engineering The University of SydneySydneyNSW 2006Australia Department of materials Science and Engineering University of North TexasDentonTX 76203USA Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Chemical Engineering The University of New South WalesSydneyNSW 2052Australia

In this study,we developed a novel confinement-synthesis approach to layered double hydroxide nanodots(LDH-NDs)anchored on carbon nanoparticles,which formed a three-dimensional(3D)interconnected network within a porous carbon support derived from pyrolysis of metal-organic frameworks(C-MOF).The resultant LDH-NDs@C-MOF nonprecious metal catalysts were demonstrated to exhibit super-high catalytic performance for oxygen evolution reaction(OER)with excellent operation stability and low overpotential(-230 mV)at an exchange current density of 10 ma·cm^(-2).The observed overpotential for the LDH-NDs@C-MOF is much lower than that of large-sized LDH nanosheets(321 mV),pure carbonized MOF(411 mV),and even commercial RuO_(2)(281 mV).X-ray absorption measurements and density functional theory(DFT)calculations revealed partial charge transfer from Fe^(3+)through an O bridge to Ni^(2+)at the edge of LDH-NDs supported by C-MOF to produce the optimal binding energies for OER ***,coupled with a large number of exposed active sides and efficient charge and electrolyte/reactant/product transports associated with the porous 3D C-MOF support,significantly boosted the OER performance of the LDH-ND catalyst with respect to its nanosheet *** from the fact that this is the first active side identification for LDH-ND OER catalysts,this work provides a general strategy to enhance activities of nanosheet catalysts by converting them into edge-rich nanodots to be supported by 3D porous carbon architectures.

关键词： carbon nanomaterials layered double hydroxide(LDH)nanodots metal-organic framework(MOF)derivatives oxygen evolution reaction

干旱胁迫下丛枝菌根真菌对月季生理指标的影响

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分子植物育种 2024年第16期22卷 5415-5423页

作者：于明华郑婷马烈田静徐峻育汪成忠苏州市园艺站苏州215128 太仓市农业农村科技服务中心太仓215400 苏州华创欣美生物种业科技有限公司苏州215300 苏州花语吴娘园艺专业合作社苏州215100 苏州农业职业技术学院苏州215008

为探讨接种丛枝菌根真菌(AMF)后月季对干旱胁迫的耐受性机制,采用盆栽试验研究了丛枝菌根真菌对干旱胁迫下月季品种抗氧化酶活性和光合特性的影响。结果表明:3个月季品种在正常浇水情况下接种Ri的菌根侵染率达到47%以上,在干旱胁迫下为... 详细信息

为探讨接种丛枝菌根真菌(AMF)后月季对干旱胁迫的耐受性机制,采用盆栽试验研究了丛枝菌根真菌对干旱胁迫下月季品种抗氧化酶活性和光合特性的影响。结果表明:3个月季品种在正常浇水情况下接种Ri的菌根侵染率达到47%以上,在干旱胁迫下为20%左右;干旱胁迫抑制了菌根的形成,但接种AMF组叶片厚度和比叶质量、可溶性蛋白含量、SOD含量、CAT含量较干旱胁迫组有显著提高,MDA含量较干旱胁迫组显著降低。表明接种AMF使月季抗氧化潜在能力得到提升;干旱胁迫下,显著降低了3个月季品种的光合能力,接种AMF后均能有效提升3个月季品种的LSP、P_(max)值,并和未接种处理达到显著差异。接种AMF能够促进3个月季品种维持抗氧化系统的稳定性,调节渗透平衡,提升光合作用能力,有效缓解干旱胁迫对3个月季品种生长的不良影响。

关键词：从枝菌根真菌干旱胁迫抗氧化酶光合特性月季品种

陕北富油煤分子模型构建及其热解提油分子动力学特性

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煤田地质与勘探 2024年第7期52卷 132-143页

作者：郭伟杨盼曦俞尊义杨甫王晶马丽李红强杨伯伦吴志强西安交通大学化学工程与技术学院陕西西安710049 陕西省能源化工过程强化重点实验室陕西西安710049 自然资源部煤炭资源勘查与综合利用重点实验室陕西西安710021 陕西省煤田地质集团有限公司陕西西安710021 西安交通大学电气工程学院陕西西安710049

【目的】富油煤结构复杂,热解反应过程与机理不明晰,需要进一步研究富油煤结构与其热解产物分布的构效关系,明晰富油煤热解提油机理。【方法】以陕北典型富油煤为研究对象,结合^(13)C NMR、FTIR和XPS等表征方法,计算并构建富油煤分子模... 详细信息

【目的】富油煤结构复杂,热解反应过程与机理不明晰,需要进一步研究富油煤结构与其热解产物分布的构效关系,明晰富油煤热解提油机理。【方法】以陕北典型富油煤为研究对象,结合^(13)C NMR、FTIR和XPS等表征方法,计算并构建富油煤分子模型,分子式为C_(444)H_(380)O_(74)N_(8)S。基于构建的富油煤分子模型,通过ReaxFF MD对陕北富油热解产物分布、热解特性以及焦油生成机理进行了深入分析。【结果和讨论】结果表明,陕北富油煤具有大量脂肪侧链和桥键等富氢结构,受热容易分解生成焦油和气体等挥发分。温度和升温速率对富油煤热解产物分布影响显著,模拟热解温度在1500 K时富油煤没有完全反应,挥发性产物质量分数为7.8%;模拟热解温度升高至2000~3000 K时,分子及自由基碎片运动越剧烈,二次反应也更明显。随着升温速率的增加,气体产物降低,而焦油产物先增加后减少;升温速率在100~200 K/ps时,富油煤没有完全热解,导致挥发分产率低于36%。根据热解产物分布推测,陕北富油煤热解反应机理是富油煤大分子中富氢结构受热断裂形成自由基碎片,进一步发生热解生成轻质焦油、重质焦油和气体产物。

关键词：富油煤煤热解分子模拟热解温度升温速率模型构建富氢结构

三种玫瑰多糖的结构特征及美容相关活性的比较研究

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食品工业科技 2024年第19期45卷 325-336页

作者：赵永雷杨付锐牛俊华郑岚马耀宏孟庆军王丙莲杨艳齐鲁工业大学(山东省科学院) 山东省科学院生物研究所山东济南250103

分别提取获得和田玫瑰多糖、苦水玫瑰多糖和平阴玫瑰多糖。测定粗多糖得率及多糖含量,利用离子色谱仪、傅里叶红外光谱仪、高效液相色谱联用多角度激光散射法、刚果红实验和碘-碘化钾实验表征多糖结构。利用体外抗氧化实验、益生元实验... 详细信息

分别提取获得和田玫瑰多糖、苦水玫瑰多糖和平阴玫瑰多糖。测定粗多糖得率及多糖含量,利用离子色谱仪、傅里叶红外光谱仪、高效液相色谱联用多角度激光散射法、刚果红实验和碘-碘化钾实验表征多糖结构。利用体外抗氧化实验、益生元实验和酪氨酸酶抑制实验分析玫瑰多糖美容相关活性。结果表明,和田玫瑰的粗多糖得率高于苦水玫瑰和平阴玫瑰(P<0.05),平阴玫瑰粗多糖中的多糖含量较低(P<0.05)。3种玫瑰多糖均包含Glc、Ara、Gal和Fru等11种单糖残基(摩尔比例不同);重均分子量在4.376×10^(5)~5.841×10^(5)Da之间(分散系数:1.35~1.72);均为含有α和β构型的吡喃糖;均不含有三螺旋结构,具有较多侧链。活性评价实验表明,3种玫瑰多糖均具有良好的抗氧化能力、益生元作用及酪氨酸酶抑制能力。在3种玫瑰多糖中,平阴玫瑰多糖具有较强的ABTS^(+)及DPPH自由基清除能力(P<0.05),而和田玫瑰多糖具有较强的酪氨酸酶抑制能力(P<0.05)。因此,3种玫瑰多糖结构具有相似性,其结构的差异导致生物学活性略有差异。3种玫瑰多糖在美容功能食品领域具有良好的开发应用前景。

关键词：玫瑰多糖结构表征抗氧化活性益生元活性酪氨酸酶抑制能力

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Influence of uniaxial tensile pre-strain on forming limit curve by using biaxial tensile test

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Chinese Journal of Aeronautics 2020年第8期33卷 2268-2280页

作者： Wennan yUAN Min WAN Xiangdong WU Bolin ma Xu LU Bing yANG Department of Mechanical Engineering and Automation Beijing University of Aeronautics and AstronauticsBeijing 100083China Research Institute of Baosteel Shanghai 201900China

This paper focused on the effect of pre-strain on forming limit curves(FLC)of 5754-O aluminum alloy sheet through utilizing biaxial tensile *** on Swift model and yld2000-2 d yield criterion,the dimensions of cruciform specimen was optimized through applying finite element method for increasing the strain at specimen *** that,with the recommended specimen size,the cruciform specimen was tested under various stroke ratios to experimentally characterize the limit strains under different pre-strain ***,the biaxial tensile tests were simulated by Abaqus to obtain the limit strains and validate the material *** can be observed in both experiments and simulations that the pre-strained uniaxial tension followed by plane tension or equi-biaxial tension can improve the formability of sheet ***,the strain path change affects the trend of first derivative of strain rate difference between neighboring points with respect to *** early increase occurred and then fell back to the stable value,the steady evolution continued until to a new increase reaching the critical *** M–K prediction approach was simulated to verify the influence of pre-strain on *** can be found that the early increase peaks of the major strain incremental ratio rose with the amplitude of ***,the phenomenon of pseudolocalization caused by the strain path change was explained through evolution of stress state inside the groove.

关键词： Aluminum alloy sheet Biaxial tensile tests Formability M–K model yld2000-2d

关中地区中深层地埋管换热器长期运行性能研究

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煤田地质与勘探 2024年第1期52卷 129-139页

作者：张智斌马真迪郝建科贾国圣柯婷婷成崇华金立文西安交通大学人居环境与建筑工程学院陕西西安710049 陕西省水工环地质调查中心陕西西安710068 陕西亚特尔科创建设有限公司陕西西安710076

我国关中地区地热资源丰富,中深层地热能供暖技术具有广阔的应用前景,而地质参数是影响中深层地埋管供暖系统性能的决定性因素。针对陕西关中地区中深层地埋管供暖性能展开研究,通过梳理关中地区咸阳市兴平市、咸阳市渭城区、西安市高... 详细信息

我国关中地区地热资源丰富,中深层地热能供暖技术具有广阔的应用前景,而地质参数是影响中深层地埋管供暖系统性能的决定性因素。针对陕西关中地区中深层地埋管供暖性能展开研究,通过梳理关中地区咸阳市兴平市、咸阳市渭城区、西安市高陵区、西安市鄠邑区、西安市长安区5个典型区域的地质参数,结合典型地埋管结构参数,对长期运行下的换热器性能及热作用半径变化规律进行模拟计算。结果表明,不同地区换热器运行之初的性能变化较为显著,但均在经过5 a左右运行后趋于稳定。地埋管深度从2000 m增至2500 m时,出口水温有着明显的提升,同一时刻下出口水温的涨幅可达8%,各采暖季末的出口水温随深度增加的变化更为显著。由于长期运行,年平均取热功率呈现下降趋势,20 a内的总降幅为11%~12%;随着换热器埋深的增加,取热功率涨幅可达41.41%~53.23%。热作用半径受埋深的影响不显著,不同埋深管道运行20 a后的井底最大热作用半径均在50 m左右;土壤温度受与换热器距离及运行时长的影响更大,距离20 m以内的土壤温度呈现明显的波动下降趋势,而距离在60 m以外的土壤温度在20 a的运行期内降幅很小。此外,由于具有大厚度新近系张家坡组(N2z)和新近系蓝田-灞河组(N2l+b)的地质条件,西安市鄠邑区、高陵区以及咸阳市兴平市等地区地埋管的出口水温、取热功率较高,更适宜开展中深层地热能供暖利用。研究成果有望为关中地区中深层地热能高效利用提供参考。

关键词：地热开发中深层地埋管地质参数取热性能热作用半径模拟分析关中地区