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Time lag characteristics of sap flow in seed-maize and their implications for modeling transpiration in an arid region of Northwest China

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Journal of Arid Land 2017年第4期9卷 515-529页

作者： bo xiaodong DU Taisheng DING Risheng Louise COMAS Center for Agricultural Water Research in China China Agricultural University Water Management Research United States Department of Agriculture Agricultural Research Service

Plant capacity for water storage leads to time lags between basal stem sap flow and transpiration in various woody plants. Internal water storage depends on the sizes of woody plants. However, the changes and its influencing factors in time lags of basal stem flow during the development of herbaceous plants including crops remain unclear. A field experiment was conducted in an arid region of Northwest China to examine the time lag characteristics of sap flow in seed-maize and to calibrate the transpiration modeling. Cross-correlation analysis was used to estimate the time lags between stem sap flow and meteorological driving factors including solar radiation（R_s） and vapor pressure deficit of the air（VPD_（air））. Results indicate that the changes in seed-maize stem sap flow consistently lagged behind the changes in R_s and preceded the changes in VPD_（air） both on hourly and daily scales, suggesting that light-mediated stomatal closures drove sap flow responses. The time lag in the maize＇s sap flow differed significantly during different growth stages and the difference was potentially due to developmental changes in capacitance tissue and/or xylem during ontogenesis. The time lags between stem sap flow and R_s in both female plants and male plants corresponded to plant use of stored water and were independent of total plant water use. Time lags of sap flow were always longer in male plants than in female plants. Theoretically, dry soil may decrease the speed by which sap flow adjusts ahead of shifts in VPD_（air） in comparison with wet soil and also increase the speed by which sap flow adjusts to R_s. However, sap flow lags that were associated with R_s before irrigation and after irrigation in female plants did not shift. Time series analysis method provided better results for simulating seed-maize sap flow with advantages of allowing for fewer variables to be included. This approach would be helpful in improving the accuracy of estimation for canopy transpiration a

关键词： seed-maize sap flow capacitance transfer function model time lag stored water use

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Double[5]carbohelicene:facile synthesis,chiroptical properties,isomerization study,and lasing application

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Science China Chemistry 2025年第1期68卷 233-240页

作者： Peipei Liu Yantong Li Meng-Xiang Wu Hao Kang Xiao-Li Zhao Lin Xu Linlin Liu xiaodong Li Junfeng Fang Zhiwei Fang Ya Cheng Hai-bo Yang Huakang Yu Xueliang Shi State Key Laboratory of Petroleum Molecular&Process Engineering Shanghai Key Laboratory of Green Chemistry and Chemical ProcessesSchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China School of Physics and Electronic Science Engineering Research Center of Nanophotonics&Advanced InstrumentMinistry of EducationEast China Normal UniversityShanghai 200241China State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China Institute of Polymer Optoelectronic Materials&Devices State Key Laboratory of Luminescent Materials&DevicesSouth China University of TechnologyGuangzhou 510640China

Double carbohelicenes have attracted considerable attention due to their aesthetic structures,distinctπ-conjugation extension,inherent chirality,and intriguing optical and electronic ***,the concise de novo synthesis of a new double[5]carbohelicene 1 together with its chiroptical properties,isomerization process and lasing application is presented.1 was synthesized by a simple protocol involving the formation of a 6,6′-bipentacene as the key *** is worth noting that1 existed as two diastereomers 1-PP/MM and 1-PM,which were successfully isolated and unambiguously confirmed by Xray *** optical resolution of the racemic 1-PP/MM was successfully achieved by chiral-phase highperformance liquid chromatography(HPLC),and 1-PP and 1-MM were characterized by circular ***,it was found that 1-PP/MM could be completely isomerized to 1-PM upon heating,and the detailed thermodynamics and kinetics of the isomerization process were systematically investigated.1-PM exhibited deep-red luminescence with emission maximum at 723 nm and fluorescence quantum yield as high as 32.95%.Consequently,we can showcase the lasing application of 1-PM by doping with epoxy resin to assemble a bottle microlaser spontaneously,which the lasing wavelength is 796.6 nm at a threshold of 0.8 m J cm^(-2).We believe that our studies,including the facile synthesis methodology,detailed isomerization studies,and lasing application,will shed some light on the design and synthesis of novel carbohelical systems with more functions.

关键词： double carbohelicene optical resolution organic laser isomerization X-ray diffraction

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炭黑充填重塑粉土单轴压缩裂隙群体发展演化测试

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复合材料学报 2017年第3期34卷 691-697页

作者：季雨坤周国庆廖波赵晓东中国矿业大学深部岩土力学与地下工程国家重点实验室徐州221008 浙江工商大学技术与工程管理系杭州310018

利用炭黑充填粉土配制了导电性的土工材料,通过表面布置分布式电极的测试方法,对其内部电阻变化率沿压缩方向进行分布式测量。研究表明:内部裂隙繁衍发展引起的电阻变化可对试样受力阶段进行同步且敏感的响应;根据不同电极间电阻变化率... 详细信息

利用炭黑充填粉土配制了导电性的土工材料,通过表面布置分布式电极的测试方法,对其内部电阻变化率沿压缩方向进行分布式测量。研究表明:内部裂隙繁衍发展引起的电阻变化可对试样受力阶段进行同步且敏感的响应;根据不同电极间电阻变化率测试值的差异,可反映试样受压破坏演化过程不同部位裂隙扩展程度。研究认为,电极间测试电阻对裂隙扩展具有敏感性,分布式电极的测试方法能够对试样破坏演化过程进行捕捉并反映不同部位裂隙群体发展变化情况,初步具有自测试的能力。

关键词：炭黑敏感性单轴压缩电阻变化率裂隙

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协调故障重构和智能软开关的柔性配电系统故障恢复策略

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电力系统及其自动化学报 2025年第1期37卷 74-83页

作者：叶云周飞张博户政丽杨晓东国网安徽省电力有限公司黄山供电分公司黄山245000 安徽省新能源利用与节能省级实验室(合肥工业大学) 合肥230009

为增强柔性配电系统在极端灾害下的故障恢复能力,提出一种协调故障重构与智能软开关的柔性配电系统故障恢复方法。首先,建立考虑运行特性的智能软开关模型,包括功率输出模型和电压控制模型,并且引入包含智能软开关的虚拟潮流模型用以判... 详细信息

为增强柔性配电系统在极端灾害下的故障恢复能力,提出一种协调故障重构与智能软开关的柔性配电系统故障恢复方法。首先,建立考虑运行特性的智能软开关模型,包括功率输出模型和电压控制模型,并且引入包含智能软开关的虚拟潮流模型用以判别智能软开关的控制模式;其次,提出协调联络开关、分段开关以及智能软开关的重构策略,建立了包含智能软开关的故障重构模型;然后,结合潮流约束、辐射状约束等约束建立柔性配电系统的故障恢复模型,采用二阶锥规划方法进行模型转化和求解;最后,在改进的IEEE 123节点测试系统上进行分析,验证所提模型的正确性和有效性。

关键词：智能软开关故障重构柔性配电系统负荷恢复韧性提升

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不同类型有机质生烃动力学特征——以渤海湾盆地KL-A构造为例

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天然气地球科学 2025年第2期36卷 354-366页

作者：王晓东王波杨纪磊郝鹏程焱李阔中海油能源发展股份有限公司工程技术分公司

油气是由干酪根在多种因素共同作用下演化形成的，难以用简单的化学反应表征。前人研究发现不同类型有机质生烃活化能存在显著差异，但具体分布规律和控制因素尚不明确，特别是有机质类型对烃源岩生烃过程的影响及其成因机制尚待阐明，... 详细信息

油气是由干酪根在多种因素共同作用下演化形成的，难以用简单的化学反应表征。前人研究发现不同类型有机质生烃活化能存在显著差异，但具体分布规律和控制因素尚不明确，特别是有机质类型对烃源岩生烃过程的影响及其成因机制尚待阐明，限制了油气资源潜力的评价。对渤海湾盆地莱州湾凹陷KL-A构造古近系不同类型湖相烃源岩开展了4组不同升温速率的开放体系热模拟实验，分析了生烃曲线拟合计算动力学参数及活化能的主要影响因素。研究结果表明：(1)化学动力学模型计算结果与实验结果的高度拟合，证明离散分布模型计算和反演有机质生烃过程的可靠性和适用性；(2)不同显微组分含量与平均活化能具有一定的相关性，各显微组分相互制约共同控制着有机质的平均活化能；(3)不同类型的有机质由于其显微组分的差异导致生烃门限、活化能分布特征和生烃转化均存在明显差异；(4)生烃热模拟实验结合生烃动力学方法，揭示有机质复杂生烃机制，为烃源岩评价与勘探提供了广泛的应用价值。

关键词：生烃动力学古近系烃源岩显微组分活化能热模拟

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Control allocation for a class of morphing aircraft with integer constraints based on Lévy flight

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Journal of Systems Engineering and Electronics 2020年第4期31卷 826-840页

作者： LU Yao SUN You LIU xiaodong GAO bo Beijing Aerospace Automatic Control Institute Beijing 100854China National Key Laboratory of Science and Technology on Aerospace Intelligence Control Beijing 100854China

Aiming at tracking control of a class of innovative control effector(ICE) aircraft with distributed arrays of actuators, this paper proposes a control allocation scheme based on the Lévy *** from the conventional aircraft control allocation problem,the particular characteristic of actuators makes the actuator control command totally subject to integer constraints. In order to tackle this problem, first, the control allocation problem is described as an integer programming problem with two desired objectives. Then considering the requirement of real-time, a metaheuristic algorithm based on the Lévy flight is introduced to tackling this problem. In order to improve the searching efficiency, several targeted and heuristic strategies including variable step length and inherited population initialization according to feedback and so on are designed. Moreover, to prevent the incertitude of the metaheuristic algorithm and ensure the flight stability, a guaranteed control strategy is designed. Finally, a time-varying simulation model is introduced to verifying the effectiveness of the proposed scheme. The contrastive simulation results indicate that the proposed scheme achieves superior tracking performance with appropriate actuator dynamics and computational time, and the improvements for efficiency are active and the parameter settings are reasonable.

关键词： flight control control allocation optimization Lévy flight tracking control

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基于CNKI的中国设施葡萄研究文献计量分析

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农业图书情报学刊 2017年第3期29卷 50-55页

作者：王引斌何燕卜晓冬冀宪武栾奕山西省农业科学院山西太原030031 山西省农业科学院农业科技信息研究所山西太原030031

目前,中国设施葡萄栽培面积发展迅速,对于设施葡萄栽培技术的研究也在向更深层次发展,本文综合运用文献计量学、统计学方法对1986年到2010年中国知网中的中国学术期刊网络出版总库中休闲观光农业类的4 313篇论文进行了全面分析。从文章... 详细信息

目前,中国设施葡萄栽培面积发展迅速,对于设施葡萄栽培技术的研究也在向更深层次发展,本文综合运用文献计量学、统计学方法对1986年到2010年中国知网中的中国学术期刊网络出版总库中休闲观光农业类的4 313篇论文进行了全面分析。从文章数量、年代分布、著者信息、期刊来源、基金概况等多方面进行计量分析,在此研究基拙上,运用内容分析法对文献计量法作了有益的补充。

关键词：设施葡萄 CNKI 科研论文文献计量学分析

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北京山区森林火灾蔓延风险评估

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生态学报 2025年第2期45卷 813-821页

作者：王博杨雪清蒋春颖赖光辉陈锋刘晓东华北科技学院应急技术与管理学院廊坊065201 森林草原火灾风险防控应急管理部重点实验室北京100083 国家林业和草原局林草调查规划院北京100714 北京市园林绿化规划和资源监测中心(北京市林业碳汇与国际合作事务中心) 北京100029

森林火灾蔓延风险(建筑物)是指林火蔓延及其对建筑物造成破坏损失的可能性,可以明确林火容易蔓延且对建筑物造成破坏损失严重的区域。科学评估森林火灾蔓延风险(建筑物),可以为森林火灾精准化防控提供科学依据,具有重要的理论和应用价... 详细信息

森林火灾蔓延风险(建筑物)是指林火蔓延及其对建筑物造成破坏损失的可能性,可以明确林火容易蔓延且对建筑物造成破坏损失严重的区域。科学评估森林火灾蔓延风险(建筑物),可以为森林火灾精准化防控提供科学依据,具有重要的理论和应用价值。以北京山区(房山、门头沟、昌平、延庆、怀柔、密云、平谷)为研究对象,基于“危险性-暴露度-脆弱性”风险评估框架,开展北京山区多尺度森林火灾蔓延风险(建筑物)评估。应用层次分析法和熵权法相结合的主客观赋权法确定指标权重,加权综合评价法和面积加权平均法计算多尺度森林火灾蔓延风险(建筑物)指数。通过自然断点分级法划分等级,空间自相关分析探讨森林火灾蔓延风险(建筑物)指数的空间关联模式。研究结果表明:(1)建筑物暴露度的综合权重达到0.5123,是影响森林火灾蔓延风险(建筑物)的主要因素。(2)北京山区森林火灾蔓延风险(建筑物)评估结果显示,高风险区域在小班、乡镇、区级尺度上分别占比3.82%、13.30%、17.95%。(3)北京山区小班尺度森林火灾蔓延风险(建筑物)指数空间异质性显著,表现出集聚分布的规律,高-高集聚型小班16641个。研究结果发现北京山区森林火灾蔓延风险(建筑物)高风险小班以侧柏、油松、灌木林为主,建议有针对性地加强建筑物密集区、森林-城镇交界域的森林可燃物管理工作。

关键词：北京山区森林火灾蔓延风险(建筑物) 暴露度脆弱性多尺度

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CNN Feature boosted SeqSLAM for Real-Time Loop Closure Detection

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Chinese Journal of Electronics 2018年第3期27卷 488-499页

作者： BAI Dongdong WANG Chaoqun ZHANG bo YI xiaodong YANG Xuejun College of Computer National University of Defense Technology State Key Laboratory of High Performance Computing National University of Defense Technology National Institute of Defense Technology Innovation

This paper proposes an efficient and robust Loop closure detection(LCD) method based on Convolutional neural network(CNN) feature. The primary method is called SeqCNNSLAM, in which both the outputs of the intermediate layer of a pre-trained CNN and the outputs of traditional sequence-based matching procedure are incorporated, making it possible to handle the viewpoint and condition variance properly. An acceleration algorithm for SeqCNNSLAM is developed to reduce the search range for the current image, resulting in a new LCD method called A-SeqCNNSLAM. To improve the applicability of A-SeqCNNSLAM to new environments, O-SeqCNNSLAM is proposed for online parameters adjustment in A-SeqCNNSLAM. In addition to the above work, we further put forward a promising idea to enhance Seq SLAM by integrating the both CNN features and VLAD’s advantages called patch based Seq CNNSLAM(P-SeqCNNSLAM), and provide some preliminary experimental results to reveal its performance.

关键词： Simultaneous localization and mapping(SLAM) Loop closure detection(LCD) Convolutional neural network(CNN) SeqSLAM SeqCNNSLAM A-SeqCNNSLAM O-SeqCNNSLAM P-SeqCNNSLAM

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Investigation of straightforward impedance eduction method on single-degree-of-freedom acoustic liners

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Chinese Journal of Aeronautics 2018年第12期31卷 2221-2233页

作者： Xianghai QIU bo XIN Long WU Yang MENG xiaodong JING Fluid and Acoustic Engineering Laboratory School of Energy and Power Engineering Beihang University

In order to address the current aircraft noise problem, the knowledge of impedance of acoustic liners subjected to high-intensity sound and grazing flow is of crucial importance to the design of high-efficiency acoustic nacelles. To this end, the present study is twofold. Firstly, the StraightForward impedance eduction Method(SFM) is evaluated by the strategy that the impedance of a liner specimen is firstly experimentally educed on a flow duct using the SFM, and then its accuracy is checked by comparing the numerical prediction with the measured wall sound pressure of the flow duct. Secondly, the effects of grazing flow and high-intensity sound on the impedance behavior of two single-layer liners are investigated based on comparisons between educed impedance and predictions by three impedance models. The performance of the SFM is validated by showing that the educed impedance leads to excellent agreement between the simulation and the measured wall sound pressure for different grazing flow Mach numbers and Sound Pressure Levels(SPLs) and over a frequency range from 3000 Hz down to 500 Hz. The grazing flow effect generally has the tendency that the acoustic resistance exhibits a slight decrease before it increases linearly with an increase in Mach,predicted successfully by the sound-vortex interaction theoretical model and the Kooi semi-empirical impedance model. However, the Goodrich semi-empirical impedance model gives only a simple linear relation of acoustic resistance starting from Mach zero. Additionally, when the SPL increases from 110 to 140 d B in the present investigation, the acoustic resistance exhibits a significant increase at all frequencies in the absence of flow; however, the resistance decreases slightly under a grazing flow of Mach 0.117. It indicates that the SPL effect can be greatly inhibited when flow is present,and the grazing flow effect can be reduced partly as well at a relatively high SPL.

关键词： Acoustic liner Experimental validation Grazing flow effect High sound intensity effect Impedance eduction Numerical evaluation Straightforward impedance eduction method

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