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Adaptive Optimal Tracking Control for Continuous-Time Systems Using Identifier-Critic Based Dynamic Programming

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Adaptive Optimal Tracking Control for Continuous-Time System...

退耕还林背景下寒地山区土地生态安全格局动态变化

第36届中国控制会议

作者： dawei hou Jing Na Yongfeng Lv Guanbin Gao Xing Wu Kunming University Of Science & Technology Faculty Of Mechanical & Electrical Engineering School of Automation Beijing Institute of Technology

ISBN: (纸本)9781538629185

This paper proposes an optimal tracking control of completely unknown affine nonlinear systems using a system augmentation scheme and a modified discounted performance function, where the feedforward and feedback control actions can be obtained simultaneously. We first present an adaptive identifier to estimate the unknown dynamics, where the estimated parameters are updated based on a new adaptive law such that these estimated parameters converge to a small neighborhood around their true values. An augmented system consisting of the tracking error and the generator of the trajectory to be tracked are then constructed, which derives an augmented tracking Hamilton-Jacobi-Bellman（HJB） equation. An online critic neural network（NN） is finally presented to approximate the optimal value function of HJB equation, and then calculate the optimal control action. This leads to an identifier-critic based adaptive dynamic programming（ADP） structure. Simulation results are presented to demonstrate the effectiveness of the proposed method.

关键词： Optimal Tracking Control Adaptive Control Adaptive Dynamic Programming System Augmentation

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农业工程学报 2017年第18期33卷 267-276页

作者：侯大伟刘艳孙华南京农业大学土地管理学院南京210095

为了研究退耕还林工程引起的土地生态安全格局变化,该文应用遥感和GIS技术对牡丹江地区2000-2014年土地利用变化特征进行了分析,并基于DPSIR概念框架构建评价指标体系,从空间上揭示了研究区退耕还林期间土地生态安全水平及格局变化。结... 详细信息

为了研究退耕还林工程引起的土地生态安全格局变化,该文应用遥感和GIS技术对牡丹江地区2000-2014年土地利用变化特征进行了分析,并基于DPSIR概念框架构建评价指标体系,从空间上揭示了研究区退耕还林期间土地生态安全水平及格局变化。结果表明,退耕还林工程的实施对研究区土地利用结构产生了极大的影响,林地面积增加1 520.16 km^2,草地、耕地面积分别减少878.50、517.14 km^2,土地利用强度先下降后上升;退耕还林工程在有效控制坡地垦殖、增加林地面积的同时,能够显著提高区域土地生态安全水平,2000-2014年,各坡度等级内安全、较安全、临界安全面积共增加1 088.6 km^2;14 a来研究区土地生态安全水平总体呈"先改善后恶化"的趋势,但仍较2000年工程实施前有了较大幅度的提升,西部、东部及南部地区土地生态安全水平显著提高,但中部牡丹江河谷盆地土地生态安全水平提升缓慢,建议新一轮退耕还林工程将此地区作为重点调控整治区域。

关键词：土地利用生态植被退耕还林土地生态安全寒地山区

Decade Milestone Advancement of Defect-Engineered g-C_(3)N_(4) for Solar Catalytic Applications

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Nano-Micro Letters 2024年第4期16卷 153-218页

作者： Shaoqi hou Xiaochun Gao Xingyue Lv Yilin Zhao Xitao Yin Ying Liu Juan Fang Xingxing Yu Xiaoguang Ma Tianyi Ma dawei Su School of Mathematical and Physical Sciences Faculty of ScienceUniversity of Technology Sydney(UTS)SydneyNSW 2007Australia Laboratory of Plasma and Energy Conversion School of Physics and Optoelectronic EngineeringLudong University186 Middle Hongqi RoadYantai 264025People’s Republic of China School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China Department of Chemistry The University of Tokyo7‑3‑1 HogoBunkyoTokyoJapan School of Science STEM CollegeRMIT UniversityMelbourneVIC 3000Australia

Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is still confronted with a general fatal issue of insufficient supply of thermodynamically active photocarriers due to its inferior solar harvesting ability and sluggish charge transfer dynamics. Fortunately, this could be significantly alleviated by the “all-in-one” defect engineering strategy, which enables a simultaneous amelioration of both textural uniqueness and intrinsic electronic band structures. To this end, we have summarized an unprecedently comprehensive discussion on defect controls including the vacancy/non-metallic dopant creation with optimized electronic band structure and electronic density, metallic doping with ultraactive coordinated environment(M–N_(x), M–C_(2)N_(2), M–O bonding), functional group grafting with optimized band structure, and promoted crystallinity with extended conjugation π system with weakened interlayered van der Waals interaction. Among them, the defect states induced by various defect types such as N vacancy, P/S/halogen dopants, and cyano group in boosting solar harvesting and accelerating photocarrier transfer have also been emphasized. More importantly, the shallow defect traps identified by femtosecond transient absorption spectra(fs-TAS) have also been highlighted. It is believed that this review would pave the way for future readers with a unique insight into a more precise defective g-C_(3)N_(4) “customization”, motivating more profound thinking and flourishing research outputs on g-C_(3)N_(4)-based photocatalysis.

关键词： Defect engineering g-C_(3)N_(4) Electronic band structures Photocarrier transfer kinetics Defect states

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燃煤电站SO3迁移转化特性试验分析

热力发电 2020年第4期49卷 29-33页

作者：侯大伟中国大唐集团科学技术研究院有限公司华东电力试验研究院安徽合肥230000

燃煤烟气中SO3质量浓度较低,性质活泼易被吸附,同时SO3捕集效率偏低,因此难以获得燃煤电厂SO3酸雾典型排放数据。本文在分析介绍主流SO3酸雾监测方法的基础上,选用异丙醇吸收法对典型燃煤电站烟气处理设备协同脱除SO3作用展开试验研究... 详细信息

燃煤烟气中SO3质量浓度较低,性质活泼易被吸附,同时SO3捕集效率偏低,因此难以获得燃煤电厂SO3酸雾典型排放数据。本文在分析介绍主流SO3酸雾监测方法的基础上,选用异丙醇吸收法对典型燃煤电站烟气处理设备协同脱除SO3作用展开试验研究。结果表明:燃煤产生的SO3质量浓度因不同的燃烧方式有较大差异,其与入炉煤质的含硫量正相关,SCR脱硝过程中SO2/SO3的转化率为0.44%~1.02%;电除尘器对于SO3的脱除效率约40%,除尘器进口SO3的质量浓度较高时,其脱除效率可略微提升,而电袋复合除尘器对于SO3的协同脱除效果更佳;湿式电除尘系统在不同工况下,对于SO3的脱除效率介于44%~75%之间,SO3排放质量浓度可控制在5 mg/m3以下;常规湿法脱硫系统SO3脱除效率在38%~56%之间,托盘塔对SO3酸雾的协同脱除效果更好。

关键词：燃煤电站 SO3 酸雾监测方法迁移转化异丙醇吸收法协同脱除

An Ultra-wideband Doubler Chain with 43–65 dBc Fundamental Rejection in Ku/K/Ka Band

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Chinese Journal of Electronics 2024年第5期33卷 1204-1217页

作者： Long WANG Jixin CHEN Debin hou Xiaojie XU Zekun LI dawei TANG Rui Zhou Hao QI Yu XIANG State Key Laboratory of Millimeter Waves Southeast University MISIC Microelectronics Co.Ltd.

In this paper, a double-balanced doubler chain with >43-dBc fundamental rejection over an ultra-wide bandwidth in 0.13-μm SiGe BiCMOS technology is proposed. To achieve high fundamental rejection, high output power, and high conversion gain over an ultra-wideband, a double-balanced doubler chain with pre-and post-drivers employs a bandwidth broadening technique and a ground shielding strategy. Analysis and comparison of the singlebalanced and double-balanced doublers were conducted, with a focus on their fundamental rejection and circuit imbalance. Three doublers, including a passive single-balanced doubler, an active single-balanced doubler, and a passive double-balanced doubler were designed to verify the performance and characteristics of the single-and doublebalanced doublers. Measurements show that the proposed double-balanced doubler chain has approximately 15 dB better fundamental rejection, and more than twice the relative bandwidth compared to the single-balanced doubler chain fabricated with the same process. Over an 86.9% 3-dB bandwidth from 13.4 GHz to 34 GHz, the double-balanced doubler chain delivers 14.7-dBm peak output power and has >43-/33-dBc fundamental/third-harmonic rejection. To the authors' best knowledge, the proposed double-balanced doubler chain shows the highest fundamental rejection over an ultra-wideband among silicon-based doublers at millimeter-wave frequency bands.

关键词： Millimeter wave technology Bandwidth Harmonic analysis Frequency conversion Millimeter wave communication Power generation Gain Doubler Double-balanced Fundamental rejection Single-balanced FREQUENCY DOUBLER POWER-AMPLIFIER GAIN COMPENSATION EFFICIENCY SILICON

Quantitative Detection and Attribution of Runoff Variations in the Aksu River Basin

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Quantitative Detection and Attribution of Runoff Variations ...

Preparation of Laser Cladding Coating Undercooling Cu-based Alloy and Co on Non-equilibrium Solidification Structure

第十五届中国水论坛

作者：孟凡浩刘铁 HUANG Yue LUO Min BAO Anming hou dawei State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences University of Chinese Academy of Sciences The College of Public Administration Nanjing Agricultural University

Since the flow variations of Aksu River are strongly influenced by climate change and human activities which threat the local ecosystem and its sustainable development, it is necessary to quantify the impact degree of driven factors. Therefore, this study aims to quantify the impacts of climate change and human activities on the variability of runoff in the Aksu River Basin. The Mann-Kendall trend test and accumulative anomaly method were used to analyse the break points of the flow difference value（FDV） between the upstream and downstream flume stations. The improved slope change ratio of cumulative quantity（SCRCQ） method and the Soil and Water Assessment Tool（SWAT） model were applied to decouple the contribution of each driving factor to the FDV variations. Furthermore, a Pearson correlation analysis was performed to show the relationships among the driving factors and the FDV. The time series prior to the year（1988） of break point was considered the baseline period. Based on the mean annual precipitation and the potential evapotranspiration（PET）, the relative impacts of precipitation, PET and human activities on FDV variations as determined by the SCRCQ method were 77.35%,-0.98% and 23.63%, respectively. In addition, the SWAT model indicated that climate factors and human activities were responsible for 92.28% and 7.72% of the variability, respectively. Thus, climate change and human activities showed a similar scale of impact on FDV changes.

关键词： runoff variation climate change human activities Aksu River

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 463-472页

作者：田徐铭 CAO Shichao hou Kai hou Xiaopeng WANG Hongfu 张煜 Department of Outpatient Xinzhou People’s HospitalXinzhou 034099China School of Mechanical Engineering North University of ChinaTaiyuan 030051China Department of Neurosurgery Xinzhou People’s HospitalXinzhou 034099China Department of Orthopedics Xinzhou People’s HospitalXinzhou 034099China

The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was *** non-equilibrium solidification structure of the under cooled alloy samples were *** is found that the rapidly solidified alloy has undergone twice grain refinement during the undercooling *** and significance of the maximum undercooling refinement structure of Cu60Ni35Co5 at T=253 K were ***-density defects were observed,such as dislocations,stacking faults networks,and twinning *** standard FCC diffraction pattern represents that it is still a single-phase *** on the metallographic diagram,EBSD and TEM data analysis,it is illustrated that the occurrence of grain refinement under high undercooling is due to stress induced *** addition,the laser cladding technology is used to coat Co-based alloy(Stellite12) coating on 304 stainless steel substrate;the microstructure of the coating cross-section was *** was found that the microstructure of the cross-section is presented as columnar crystals,planar crystals,and disordered growth direction,so that the coating has better hardness and wear *** electrochemical corrosion of the substrate and coating,it can be seen that the Co and Cr elements present in the coating are more likely to form a dense passivation film,which improved the corrosion resistance of the coating.

关键词： non-equilibrium solidification structure undercooling recrystallization laser cladding coating

Integral Operators Between Fock Spaces

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 265-278页

作者： Yongqing LIU Shengzhao hou School of Mathematics and Statistics Changshu Institute of TechnologySuzhou 215006JiangsuChina School of Mathematical Sciences Soochow UniversitySuzhou 215006JiangsuChina

In this paper,the authors study the integral operator■induced by a kernel functionφ(z,·)∈F_α~∞between Fock *** 1≤p≤∞,they prove that S_φ:F_α^(1)→F_α^(p)is bounded if and only if■where k_(a)is the normali... 详细信息

关键词： Fock spaces Integral operators Normalized reproducing kernel

Herbivore and native plant diversity synergistically resist alien plant invasion regardless of nutrient conditions

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Plant Diversity 2024年第5期46卷 640-647页

作者： Liping Shan Meng hou Key Laboratory of Wetland Ecology and Environment State Key Laboratory of Black Soils Conservation and UtilizationNortheast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China

Alien plant invasion success can be inhibited by two key biotic factors:native herbivores and plant ***,few studies have experimentally tested whether these factors interact to synergistically resist invasion success,especially factoring in changing global environments(*** enrichment).Here we tested how the synergy between native herbivores and plant diversity affects alien plant invasion success in various nutrient *** this purpose,we exposed alien plant species in potmesocosms to different levels of native plant diversity(4 vs.8 species),native generalist herbivores,and high and low soil nutrient *** found that generalist herbivores preferred alien plants to native plants,inhibiting invasion success in a native *** inhibition was amplified by highly diverse native ***,the amplified effect between herbivory and native plant diversity was independent of nutrient *** results suggest that a higher diversity of native communities can strengthen the resistance of native generalist herbivores to alien plant invasions by enhancing herbivory *** synergistic effect remains in force in nutrient-enriched habitats that are always invaded by alien plant *** results shed light on the effective control of plant invasions using multi-trophic means,even in the face of future global changes.

关键词： Biological invasion Biotic resistance Diversity conservation Plant-herbivore interactions Resource availability Global change