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Whole-cell recording of the robust nucleus of the arcopallium neurons in the adult zebra finch

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Neural Regeneration Research 2009年第8期4卷 623-628页

作者： Suqun liao Xiaolin liu dongfeng li College of life Sciences South China Normal University Guangzhou 510631 Guangdong Province China

BACKGROUND： Electrophysiological properties of the song nucleus have been revealed using conventional techniques, such as intracellular and extracellular recording. Research concerning the neuronal activation properties and regulations of the song system at the cellular and ion channel level may help reveal the neural mechanism of song learning. OBJECTIVE： To perform whole-cell recording of robust nucleus of the arcopallium （RA） neurons in brain slices from adult zebra finches （Taeniopygia guttata） and observe the action potential, sodium/potassium current and the spontaneous postsynaptic current of RA neurons. DESIGN, TIME AND SETTING： Self-controlled, neuroelectrophysiological experiment. The study was performed at the Neurophysiology Laboratory of South China Normal University from April to September 2008. MATERIALS： Flaming/Brown puller P-97 was purchased from Sutter Ins, USA; Axopatch 700B amplifier and Digidata 1332A converter were purchased from Axon Instrument, USA; pClamp software was provided by Axon Instrument, USA. METHODS： RA neurons were acutely isolated from 24 healthy male zebra finches. The action potential, voltage-gate sodium/potassium current and spontaneous postsynaptic current were recorded by whole-cell recording technology. Data were analyzed by pClamp software. MAIN OUTCOME MEASURES： The amplitude and frequency of the action potential, and the amplitude of the voltage-dependent and spontaneous postsynaptic currents, were measured. RESULTS：（1） Testing of action potential： Cells exhibited a stable current-voltage relationship following a series of hyperpolarization stepped currents, and an action potential was triggered by the spike threshold. All the recorded cells displayed repetitive firing following depolarizing current injection, with a frequency beyond 100 Hz. （2） Testing of voltage-gate currents： The inward and outward whole-cell currents were observed after a series of depolarizing voltage steps. The inward current disappeared followi

关键词： adult zebra finch robust nucleus of the arcopallium whole-cell recording

Minimal wave speed of a diffusive SIR epidemic model with nonlocal delay

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International Journal of Biomathematics 2019年第7期12卷 179-197页

作者： Fuzhen Wu dongfeng li Department of Basic Zhejiang University of Water Resources and Electric PowerHangzhouZhejiang 310018P.R.China College of Hydraulic and Environmental Engineering Zhejiang University of Water Resources and Electric Power Hangzhou Zhejiang 310018P.R.China

This paper is concerned with the minimal wave speed in a diffusive epidemic model with nonlocal *** define a *** presenting the existence and the nonexistence of traveling wave solutions for all positive wave speed,we confirm that the threshold is the minimal wave speed of traveling wave solutions,which models that the infective invades the habitat of the *** some cases,it is proven that spatial nonlocality may increase the propagation threshold while time delay decreases the threshold.

关键词： Upper-lower solutions asymptotic spreading nonmonotone system

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带肋FRP筋与混凝土的粘结强度预测方法

土木与环境工程学报（中英文） 2025年第1期47卷 130-141页

作者：董恒磊李东风蔡庆森王代玉哈尔滨工业大学(深圳)理学院广东深圳518000 深圳市龙岗区建筑工务署广东深圳518100 哈尔滨工业大学土木工程学院哈尔滨150090

目前有关带肋纤维增强复合材料(FRP)筋粘结性能的研究不足。收集粘结纤维肋FRP筋(简称粘结肋FRP筋)和机械刻槽肋FRP筋(简称刻槽肋FRP筋)的试验数据,探究各参数对粘结性能的影响。结果表明:两种带肋FRP筋的宏观破坏模式都是拔出破坏,在... 详细信息

目前有关带肋纤维增强复合材料(FRP)筋粘结性能的研究不足。收集粘结纤维肋FRP筋(简称粘结肋FRP筋)和机械刻槽肋FRP筋(简称刻槽肋FRP筋)的试验数据,探究各参数对粘结性能的影响。结果表明:两种带肋FRP筋的宏观破坏模式都是拔出破坏,在细观上粘结肋FRP筋主要为FRP筋肋的剪切剥落,而混凝土损伤较轻微,大部分刻槽肋FRP筋表现为混凝土肋剪切破坏,二者的粘结强度随混凝土强度的增加而增大;增加保护层厚度可增强混凝土对FRP筋的约束效果,有助于提高粘结肋FRP筋的粘结强度,但对刻槽肋FRP筋几乎没有影响;增加相对肋高hrd和FRP筋肋宽比FR可提高粘结肋FRP筋的粘结强度;而刻槽肋FRP筋几乎不受hrd的影响,主要受混凝土肋宽比C_(R)的影响,其粘结强度随C_(R)的增加而增大;建立的粘结强度公式计算值与试验结果吻合较好,预测精度高于设计规范,主要原因在于该公式准确考虑了FRP筋肋成型工艺和几何特征对粘结强度的影响。

关键词：带肋FRP筋肋成型工艺肋几何特征粘结破坏模式粘结强度理论计算公式

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liquid-holdup regions research of novel reactive distillation column for C5 fraction separation

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Chinese Journal of Chemical Engineering 2017年第4期25卷 433-441页

作者： liang Guo Tiefeng Wang dongfeng li Jinfu Wang Beijing Key Laboratory of Green Reaction Engineering and Technology Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Beijing Research Institute of Chemical Industry Beijing 100013China

Recent advances in technologies of reactive distillation(RD) offer various design concepts for chemical *** separation of cracking C5 fraction, one of the main challenges is improving the conversion of cyclopentadiene(CPD) and the recovery of isoprene(IP). In the current work, a novel reactive distillation column with several liquid-holdup regions was designed, since it allows long residence time and provides flexibility for narrowing the efficiency gap between reaction and distillation. By use of Aspen Plus, a corresponding mathematic model was established and verified to be accurate. Following that, comprehensive studies were carried out for the design of liquid-holdup regions position. Details and principles about the separation performance with the liquid-holdup regions were revealed and optimized parameters were determined with 100 theoretical plates,feed position of 35 th plate, and four liquid-holdup regions at 25 th, 60 th, 75 th and 90 th plate. The designed RD column could well meet the technical requirement, and influence of other important factors including residence time, operating pressure and reflux ratio was further investigated.

关键词： distillation residence Aspen verified cracking requirement challenges selectivity hence enthalpy

Morph-and hydro-dynamic effects toward flood conveyance and navigation of diversion channel

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International Journal of Sediment Research 2016年第3期31卷 264-270页

作者： Min Xu li Chen Qihui Wu dongfeng li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

The functions of the diversion channel are usually disturbed by sediment erosion and *** the effects of unsaturated sediment flow and narrowed cross section the diversion channel is enormously *** discharge capacity,however,is deteriorated for the local deposition which lessens the water depth to satisfy the minimum navigable flow *** this study,the alternative diversion channel with unsaturated sediment flow at Hanjiang River,China,was taken as an *** impacts of bed morphology for flood events and normal flow conditions were *** results show that the consideration of bed morphology is essential to design the diversion *** for the unsaturated and eroded channel,the local deposition can reduce the water depth and restrict the navigable requirement under normal flow conditions.

关键词： Diversion channel Bed morphology Navigation condition Discharge capacity Channel design

Safety limitations of Large New-Built Seagoing Vessels Towed through Bridge Area

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Wuhan University Journal of Natural Sciences 2015年第6期20卷 543-548页

作者： li dongfeng liU Mingjun CHEN li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University School of Navigation Wuhan University of Technology

The safety limitation of large new-built seagoing ves- sel design and operation is investigated to ensure safety of the new vessels towed through bridge area. We analyze the maneuverabil- ity characteristics of a towing fleet, and develop a mathematical drift model of ship motion for the fleet. Based on this drift model and the hydro-meteorological conditions in bridge area, we pro- pose a method to systematically ascertain the safety limitations of water stages, current, wind, speed and visibility. This method is conducive to the safety of both navigation and bridges when large towing fleets transit through bridges.

关键词： large new-built seagoing vessel towing formation bridge area safety limitations

In vivo synaptic transmission in the zebra finch high vocal center and robust nucleus of the arcopallium after different stimulus patterns

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Neural Regeneration Research 2008年第5期3卷 472-477页

作者： Suqun liao Wenxiao liu Peng Xiao dongfeng li College of life Sciences South China Normal University Guangzhou 510631 Guangdong Province China

BACKGROUND： Electrophysiological studies using brain slices have revealed that the developmental regulation of synaptic plasticity in vocal learning pathway is essential for song learning in zebra finches. Publications reporting in vivo electrophysiological investigation are scarce. Many aspects of neural mechanisms underlying song learning and production still remain uncertain. OBJECTIVE： To observe the efficacy of paired pulses and the effect on synaptic transmission induced by low-frequency stimulations, high-frequency stimulations, and theta-burst stimulations. DESIGN, TIME AND SETTING： A comparative observation. The experiment was conducted from October 2006 to October 2007 in the Neurophysiology Laboratory of South-China Normal University. MATERIALS： Twenty-four adult male zebra finches were supplied by the Department of Animal Experiment of College of life Sciences, South China Normal University. A SEN-7203 stimulator （NIHON KOHDEN）, as well as a DSJ-731WF microelectrode amplifier and DSJ-F amplifier （provided by South-China Normal University）, were used to stimulate and record, respectively. METHODS： Animals were randomly divided into low-frequency, high-frequency, and theta-burst frequency stimulation groups. After recording evoked potentials, an input-output curve was evaluated. Subsequently, the efficacy of paired pulses with different stimulus intensity （1/3, 1/2, 2/3, or 3/4 of the value that induced the largest synaptic response）, as well as interpulse intervals （50, 75, and 100 ms）, was measured in each group. The test stimulus intensity was set to a level that evoked 1/2 or 1/3 amplitude of the maximum response. MAIN OUTCOME MEASURES： Changes in amplitude, slope, and area of evoked potentials elicited by different stimulus patterns. RESULTS：（1） Efficacy of paired pulses： there was significant paired-pulse facilitation in the high vocal center and robust nucleus of the arcopallium （HVC-RA） synapse. Efficacy decreased when paired-pulse intervals or st

关键词： electrical stimulus patterns synaptic transmission in vivo zebra finch

Relationship between the equilibrium morphology of river islands and flow-sediment dynamics based on the theory of minimum energy dissipation

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International Journal of Sediment Research 2022年第4期37卷 514-521页

作者： Xuhai Yang Zhaohua Sun Jinyun Deng dongfeng li Yitian li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Geography National University of Singapore

River islands are vital geomorphic units in alluvial rivers, and the variation of their morphology and position plays a significant role in regulating flow-sediment transport and channel stability. Based on the theories of minimum energy dissipation theory of fluid movement and river morphodynamics, this study uses the river islands in anabranching channels to analyze the relationship between the shape coefficient of river island and the flow-sediment dynamics under stable equilibrium conditions. Results indicate that the river islands could adjust their lengths and widths to reach an appropriate allocation of flow diversion ratio and sediment separation ratio in the two anabranching channels to ensure flow-sediment being smoothly transported downstream and achieve the minimum energy dissipation. Under the minimum energy dissipation condition of flow-sediment transport balance, the ratio of “sediment separation ratio” to “flow diversion ratio” in short and straight branching channels is between 1 and *** the proportion of flow-sediment transport reaches its maximum, the steady island morphology coefficient is approximately 0.2; that is, the island length is five times the width. We verify the steady island morphology coefficients using two typical islands in the middle and lower reaches of the Yangtze River and find the relative error is within ±3%.

关键词： Equilibrium morphology of islands Flow-sediment dynamics Minimum energy dissipation theory Sediment separation ratio Flow diversion ratio

Activation of hematite photoanode synthesized at low temperature by W doping

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Journal of Energy Chemistry 2024年第10期97卷 149-155,I0004页

作者： Changtong Ma dongfeng li lin liu Xiuli Wang Hongxian Han State Key Laboratory of Catalysis and Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China

*** Solar water splitting offers a promising approach for green hydrogen production[1].There are many ways to achieve solar water splitting,such as photocatalytic(PC)water splitting,photoelectrochemical(PEC)water spli... 详细信息

关键词： Hematite Solar water splitting Charge separation Charge transfer