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Seasonal variation and ecological importance of tannin and nutrient concentrations in Casuarina equisetifolia branchlets and fine roots

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Journal of Forestry Research 2020年第5期31卷 1499-1508页

作者： Lihua zhang Shangju zhang Gongfu Ye Xiaochun Qin School of Biological Science and Technology University of JinanJinan 250022People’s Republic of China Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research(YIC)Chinese Academy of Sciences(CAS)Shandong Provincial Key Laboratory of Coastal Environmental ProcessesYICCASYantai 264003People’s Republic of China Pingtan State-Owned Protection Forest Farm of Fujian Province Pingtan 350400People’s Republic of China Fujian Academy of Forestry Fuzhou 350012People’s Republic of China

In this study,we investigated the effects of environmental factors on plant phenolic variability,seasonal dynamics of total phenolic content(TP),extractable condensed tannins(ECT),protein-bound condensed tannins(PBCT),fiber-bound condensed tannins(FBCT),total condensed tannins(TCT),protein precipitation capacity(PPC)and nutrient content in the branchlets and fine roots of Casuarina *** and TCT concentrations in branchlets were lowest in the spring,then increased in summer and autumn,similar to the seasonal dynamics in air *** and TCT concentrations in fine roots were highest in summer,coinciding with heavy *** general,TP and TCT concentrations were higher in branchlets than in fine *** significant difference was found in C concentration among various seasons for either branchlets or fine *** had significantly higher N and P concentrations than fine roots in most *** C/N and N/P ratios in branchlets were significantly lower than in fine roots in all seasons,except *** relationship between branchlets and fine roots was significant for C,P and FBCT,but no significant relationships were found for N,TP,ECT,PBCT and ***,TP and TCT content were each significantly correlated with PPC in branchlets and in fine *** TP/N and TCT/N ratios were highest in the autumn for the branchlets and in the summer for fine *** results indicate that high temperatures lead to increased tannin production in branchlets,but that the tannin content in fine roots is mainly affected by *** content was greater in branchlets than in fine roots,which may indicate that selective pressure is greater on branchlets than on fine roots.

关键词： Casuarina equisetifolia Condensed tannins Total phenolic content Nutrient Seasonal variation

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Wing kinematics measurement and aerodynamics of free-flight maneuvers in drone-flies

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Acta Mechanica Sinica 2010年第3期26卷 371-382页

作者： Yanlai zhang Mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Institute of Fluid Mechanics Beihang University 100191 Beijing China

The time courses of wing and body kinematics of two free-flying drone-flies, as they performed saccades, were measured using 3D high-speed video, and the morpho- logical parameters of the wings and body of the insects were also measured. The measured wing kinematics was used in a Navier-Stokes solver to compute the aerodynamic forces and moments acting on the insects. The main results are as following. （1） The turn is mainly a 90° change of heading. It is made in about 10 wingbeats （about 55 ms）. It is of interest to note that the number of wingbeats taken to make the turn is approximately the same as and the turning time is only a little different from that of fruitflies measured recently by the same approach, even if the weight of the droneflies is more than 100 times larger than that of the fruitflies. The long axis of body is about 40° from the horizontal during the maneuver. （2） Although the body rotation is mainly about a vertical axis, a relatively large moment around the yaw axis （axis perpendicular to the long axis of body）, called as yaw moment, is mainly needed for the turn, because moment of inertial of the body about the yaw axis is much larger than that about the long axis. （3） The yaw moment is mainly pro- duced by changes in wing angles of attack： in a right turn, for example, the dronefly lets its right wing to have a rather large angle of attack in the downstroke （generally larger than 50°） and a small one in the upstroke to start the turn, and lets its left wing to do so to stop the turn, unlike the fruitflies who generate the yaw moment mainly by changes in the stroke plane and stroke amplitude.

关键词： Drone-fly - Maneuver Wing kinematicsmeasurement Aerodynamics Navier-Stokes simulation

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Robust Exponential Stability of Switched Interval Interconnected Systems with Unbounded Delay

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Journal of Systems Science & Complexity 2017年第6期30卷 1316-1331页

作者： XUE Huanbin zhang Jiye College of Mathematics and Statistics Hanshan Normal University State Key Laboratory of Traction Power Southwest Jiaotong University

In this paper, a class of switched interval interconnected systems with unbounded delay were investigated. On the assumption that the interconnected functions of the systems satisfied the global Lipschitz condition, by using vector Lyapunov methods and M-matrix theory, the integrodifferential inequalities with unbounded delay were constructed. By the stability analysis of the integrodifferential inequalities, the sufficient conditions to ensure the robust exponential stability of the interval interconnected systems were obtained. By using average dwell time approach, conditions for guaranteeing the robust exponential stability of the switched delay interval interconnected systems were ***, two numerical examples were given to illustrate the correction and effectiveness of the proposed theory.

关键词： Average dwell time interconnected systems robust stability switching rule unbounded delay

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Fast Fading Channel Estimation for OFDM Systems with Complexity Reduction

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Chinese Journal of Electronics 2021年第6期30卷 1173-1177页

作者： zhang Chen LI Dan College of Electronic Science and Technology National University of Defense Technology

Channel estimation plays a significant role in the Inter-carrier interference(ISI) mitigation and symbol detection in Orthogonal frequency division multiplexing(OFDM) systems. As the speed of mobile terminal increases, the channel changes rapidly, causing fast fading which will degrade the system performance. In this paper, a low complexity fast fading channel estimation method suited for scattered pilot OFDM systems is proposed. This method is characterized by estimating channel matrix directly in the frequency domain, which can significantly reduce the channel estimation complexity with good system performance. Simulation results verify its superiority over the existing estimation methods.

关键词： low complexity fast fading channel estimation OFDM modulation existing estimation methods channel estimation OFDM systems mobile terminal increases good system performance symbol detection channel estimation complexity frequency-domain analysis channel changes fading channels complexity reduction channel matrix

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Split nitrogen fertilizer application improved grain yield in winter wheat (Triticum aestivum L.) via modulating antioxidant capacity and ^(13)C photosynthate mobilization under water-saving irrigation conditions

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Ecological Processes 2021年第1期10卷 290-302页

作者： Zhen zhang Zhenwen Yu Yongli zhang Yu Shi Key Laboratory of Crop Ecophysiology and Farming System Ministry of AgricultureShandong Agricultural UniversityTai-an 271017ShandongChina

A water-saving cultivation technique of supplementary irrigation based on soil moisture levels has been adopted for winter wheat production in the Huang-Huai-Hai Plain of China,due to the enhanced water-use ***,appropriate split nitrogen management may further improve crop growth and grain ***,we conducted a 2-year field experiment to determine if split nitrogen management might improve wheat productivity by enhancing ^(13)C photosynthate mobilization and the antioxidant defense system under water-saving *** nitrogen management involved a constant total nitrogen rate(240 kg ha^(−1))split in four different proportions between sowing and jointing stage,i.e.,10:0(N1),7:3(N2),5:5(N3),and 3:7(N4).The N3 treatment significantly enhanced“soil-plant analysis development”values,superoxide dismutase antioxidant activity,soluble protein content,sucrose content,and sucrose phosphate synthetase activity,although it reduced the accumulation of malondialdehyde(MDA).The N3 treatment ultimately increased the amount of dry matter assimilation after anthesis *** addition,the ^(13)C isotope tracer experiment revealed that the N3 treatment promoted the assimilation of carbohydrates after anthesis and their partitioning to the developing *** to the unequal ratio treatments(N1,N2,and N4),the equal ratio treatment(N3)increased grain yield by 5.70–16.72%via increasing 1000-grain weight and number of grains per spike in both growing ***,we recommend the use of a 5:5 basal-topdressing split nitrogen fertilizer application under water-saving irrigation conditions to promote antioxidant enzyme activity and the remobilization of photosynthate after anthesis for improving wheat grain yield.

关键词： Split nitrogen fertilization Modulating antioxidant capacity ^(13)C photosynthate mobilization Water-saving irrigation

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In-situ reduced graphene oxide-polyvinyl alcohol composite coatings as protective layers on magnesium substrates

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Progress in Natural Science:Materials International 2017年第3期27卷 326-328页

作者： Xingkai zhang Yan Zhou Junyan zhang R & D Center of Lubricating and Protecting Materials Lanzhou Institute of Chemical PhysicsChinese Academy of Sciences

A simple and feasible method was developed to fabricate in-situ reduced graphene oxide-polyvinyl alcohol composite(GO-PVA) coatings as protective layers on magnesium *** alcohol was used as an in-situ reductant to transform GO into reduced *** and uniform GO-PVA coatings were prepared on magnesium substrates by dip-coating method,and were further thermally treated at 120 ℃ under ambient condition to obtain in-situ reduced GO-PVA *** to the reducing effect of *** treatment at low temperature led to effective in-situ reduction of GO as confirmed by XRD,Raman,FTIR and XPS *** corrosion current density of magnesium substrates in 3.5 wt%NaCl solution could be lowered to its 1/25 when using in-situ reduced GO-PVA coatings as protective layers.

关键词： Graphene oxide in-situ reduction Polyvinyl alcohol Composite coatings Corrosion resistance

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Balance control of grid currents for UPQC under unbalanced loads based on matching-ratio compensation algorithm

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Journal of Modern Power Systems and Clean Energy 2018年第6期6卷 1319-1331页

作者： Xiaojun ZHAO Chunjiang zhang Xiuhui CHAI Jinlong zhang Fanqi LIU Zhe zhang Department of Electrical Engineering Yanshan University Department of Electrical Engineering Technical University of Denmark

In three-phase four-wire systems, unbalanced loads can cause grid currents to be unbalanced, and this may cause the neutral point potential on the grid side to shift. The neutral point potential shift will worsen the control precision as well as the performance of the threephase four-wire unified power quality conditioner(UPQC),and it also leads to unbalanced three-phase output voltage,even causing damage to electric equipment. To deal with unbalanced loads, this paper proposes a matching-ratio compensation algorithm(MCA) for the fundamental active component of load currents, and by employing this MCA,balanced three-phase grid currents can be realized under 100% unbalanced loads. The steady-state fluctuation and the transient drop of the DC bus voltage can also be restrained. This paper establishes the mathematical model of the UPQC, analyzes the mechanism of the DC bus voltage fluctuations, and elaborates the interaction between unbalanced grid currents and DC bus voltage fluctuations;two control strategies of UPQC under three-phase stationary coordinate based on the MCA are given, and finally, the feasibility and effectiveness of the proposed control strategy are verified by experiment results.

关键词： Unified power quality conditioner(UPQC) Unbalanced loads Matching-ratio compensation Balance control DC bus voltage fluctuations

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Blind channel estimation for multiple antenna OFDM system subject to unknown carrier frequency offset

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Journal of Systems Engineering and Electronics 2014年第5期25卷 721-727页

作者： Xiaofei zhang Dazhuan Xu Department of Electronic Engineering Nanjing University of Aeronautics and Astronautics

The problem of channel estimation for multiple an- tenna orthogonal frequency division multiplexing （OFDM） systems subject to unknown carrier frequency offset （CFO） is addressed. Multiple signal classification （MUSIC）-Iike algorithm, which generally has been used for direction estimation or frequency estimation, is used for channel estimation in multiple antenna OFDM systems. A reduced dimensional （RD）-MUSIC based algorithm for channel estimation is proposed in multiple antenna OFDM systems with unknown CFO. The Cramer-Rao bound （CRB） of channel estimation in multiple antenna OFDM systems with unknown CFO is derived. The proposed algorithm has a superior performance of channel estimation compared with the Capon method and the least squares method.

关键词： channel estimation orthogonal frequency division multiplexing (OFDM) multiple antennas multiple signal classification (MUSIC).

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A MULTI-PERIOD PRICING AND INVENTORY CONTROL MODEL

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Journal of Systems Science & Complexity 2010年第2期23卷 249-260页

作者： Juliang zhang Jian CHEN Department of Logistics Management School of Economics and Management Beijing Jiaotong UniversityBeijing 100044 China. Department of Management Science and Engineering School of Economics and Management Tsinghua University Beijing 100084 China.

The authors analyze a finite horizon,single product,period review model in which pricingand inventory decisions are made *** in different periods are random variablesthat are independent of each other and their distributions depend on the product *** andordering decisions are made at the beginning of each period and all shortage are *** is a convex function of the amount *** objective is to find an inventory and pricing policymaximizing expected discounted profit over the finite *** authors characterize the structure ofthe optimal combined pricing and inventory strategy for this ***,the authors demonstratehow the profit-to-go function,order up to level,reorder point and optimal price change with respectto state and time.

关键词： Convex cost function planning horizon pricing stochastic inventory management uncertainty.

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Integrative cancer genomics： models, algorithms and analysis

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Frontiers of Computer Science 2017年第3期11卷 392-406页

作者： Jinyu CHEN Shihua zhang National Center for Mathematics and Interdisciplinary Sciences Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In the past decade, the remarkable development of high-throughput sequencing technology accelerates the generation of large amount of multiple dimensional data such as genomic, epigenomic, transcriptomic and proteomic data. The comprehensive data make it possible to understand the underlying mechanisms of biology and disease such as cancer systematically. It also provides great challenges for computa- tional cancer genomics due to the complexity, scale and noise of data. In this article, we aim to review the recent develop- ments and progresses of computational models, algorithms and analysis of complex data in cancer genomics. These topics of this paper include the identification of driver mutations, the genetic heterogeneity analysis, genomic markers discovery of drug response, pan-cancer scale analysis and so on.

关键词： cancer genomics model algorithm data integration bioinformatics computational biology

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