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基于双约束条件的移动机器人轮速控制仿真

计算机仿真 2024年第7期41卷 491-495页

作者：王可庆汪磊席万强无锡学院自动化学院江苏无锡214105 江南大学物联网工程学院江苏无锡214122

由于高速轮式移动机器人在转向过程中极易发生打滑现象,如果不能很好地控制轮速将容易出现事故,造成不可估量的损失。为此,提出一种高速轮式移动机器人轮速自动控制方法。在全局惯性坐标系中建立移动机器人运动学模型,分析转向过程中发... 详细信息

由于高速轮式移动机器人在转向过程中极易发生打滑现象,如果不能很好地控制轮速将容易出现事故,造成不可估量的损失。为此,提出一种高速轮式移动机器人轮速自动控制方法。在全局惯性坐标系中建立移动机器人运动学模型,分析转向过程中发生打滑和没有发生打滑的现象,得到机器人速度和加速度的约束条件;针对移动机器人轮速控制目标量建立合力矩,并为每一个车轮都分配一个力矩值,设定上限令轮速保持在合理范围内;由合力矩分配策略推理得到每个车轮的力矩值,再由力矩值反推得到每个车轮的轮速控制量,由此实现机器人轮速自动控制。仿真结果表明,所提方法对于速度和加速度的控制效果较好,可令机器人更加安全稳定地运行。

关键词：高速轮式移动机器人轮速自动控制加速度约束条件运动学模型

Beneficial effects of protocatechuic acid on diabetic retinopathy in streptozocin-induced diabetic rats

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International Journal of Ophthalmology(English edition) 2023年第6期16卷 855-862页

作者： Ling wan Jun Li Wei-Bai Chen Guo-qiang Wu Department of Ophthalmology Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072Sichuan ProvinceChina Department of Ophthalmology Chinese Academy of Sciences Sichuan Translational Medicine Research HospitalChengdu 610072Sichuan ProvinceChina Department of Ophthalmology the First People’s Hospital of Lanzhou CityLanzhou 730050Gansu ProvinceChina

·AIM:To determine the effects of protocatechuic acid(PCA)on streptozocin-induced diabetic retinopathy(DR)in rats.·METHODS:Wistar rats were given a 50 mg/kg intraperitoneal injection of streptozocin to induce *** were assigned randomly one of four groups(8 rats per group):control,diabetic,diabetic plus PCA(25 mg/kg·d),and diabetic plus PCA(50 mg/kg·d).After inducing diabetes,treatments were started one week later and continued for eight *** the experiment,the rats were sacrificed,and their retinas were taken for biochemical and molecular analysis.·RESULTS:PCA administration diminished the blood glucose and glycated haemoglobin levels relative to the diabetic *** diabetic rats,PCA lowered elevated levels of advanced glycosylated end products(AGEs)and receptor for AGEs(RAGE).In the retina of diabetic rats,PCA effectively decreased inflammatory cytokine,nuclear factor-κB,tumour necrosis factor-α,interleukin-1β,and vascular endothelial growth factor,and increased antioxidant markers glutathione,superoxide dismutase,and catalase.·CONCLUSION:The protective benefits of PCA against DR may be attributable to its suppression of the AGEs and RAGE and its antioxidant and anti-inflammatory properties.

关键词： diabetic retinopathy streptozocin protocatechuic acid oxidative stress vascular endothelial growth factor

MoS2 yolk-shell microspheres with a hierarchical porous structure for efficient hydrogen evolution

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Nano Research 2016年第10期9卷 3038-3047页

作者： Qiqi Zhang Hua Bai Qing Zhang qiang Ma Yahui Li Chongqing wan Guangcheng Xi Department of Chemistry Capital Normal University No. 105 North Road West 3th Ring Road Beijing 100048 China Nanomaterials and Nanoproducts Research Center Chinese Academy of Inspection and Quarantine No. 11 Ronghua South Road Beijing 100176 China

Yolk-shell architectures have attracted extensive attention owing to their unique structure and infusive applications. MoS2 is regarded as one of the most promising catalytic materials for hydrogen evolution by the splitting of water. In this work, a simple self-template solvothermal approach is developed for the synthesis of novel MoS2 yolk-shell microspheres with a hierarchical porous structure by reacting MoO2 microspheres with L-cysteine. A dissolution- recrystallization formation mechanism is proposed for the MoS2 yolk-shell microspheres. Owing to structural superiority, the new material architecture exhibits improved photoelectrochemical properties, including efficient hydrogen evolution reaction catalytic activities, a high photocurrent density, a small overpotential, and a low charge-transfer resistance.

关键词： yolk-shell structure hydrogen molybdenum sulfide photoelectrochemical electrochemical

Reduced precision solution criteria for nonlinear model predictive control with the feasibility-perturbed sequential quadratic programming algorithm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第11期12卷 919-931页

作者： Jiao-na wan Zhi-jiang SHAO Ke-xin wan Xue-yi FANG Zhi-qiang wanG Ji-xin QIAN State Key Lab of Industrial Control Technology Institute of Industrial Control Department of Control Science and Engineering Zhejiang University Hangzhou 310027 China

We propose a novel kind of termination criteria, reduced precision solution (RPS) criteria, for solving optimal control problems (OCPs) in nonlinear model predictive control (NMPC), which should be solved quickly for new inputs to be applied in time. Computational delay, which may destroy the closed-loop stability, usually arises while non-convex and nonlinear OCPs are solved with differential equations as the constraints. Traditional termination criteria of optimization algorithms usually involve slow convergence in the solution procedure and waste computing resources. Considering the practical demand of solution precision, RPS criteria are developed to obtain good approximate solutions with less computational cost. These include some indices to judge the degree of convergence during the optimization procedure and can stop iterating in a timely way when there is no apparent improvement of the solution. To guarantee the feasibility of iterate for the solution procedure to be terminated early, the feasibility- perturbed sequential quadratic programming (FP-SQP) algorithm is used. Simulations on the reference tracking performance of a continuously stirred tank reactor (CSTR) show that the RPS criteria efficiently reduce computation time and the adverse effect of computational delay on closed-loop stability.

关键词： Nonlinear model predictive control (NMPC) Computational delay Termination criteria Continuously stirred tankreactor (CSTR)

SIRT6在横纹肌代谢及相关疾病中的研究进展

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生命科学 2024年第8期36卷 1098-1105页

作者：田宝凯杨旸段子强万根萌常波衣雪洁沈阳体育学院运动健康学院沈阳110102 上海体育大学运动健康学院上海200438 沈阳体育学院体育社会科学研究中心沈阳110102

SIRT6是一种染色质相关的NAD+依赖性酶,广泛表达于哺乳动物的所有组织中,在维持生命健康中发挥着至关重要的作用。横纹肌(骨骼肌和心肌)作为人体的重要组成部分,承担着能量代谢、姿势维持以及推动血液流动等多重功能,对维持机体生命活... 详细信息

SIRT6是一种染色质相关的NAD+依赖性酶,广泛表达于哺乳动物的所有组织中,在维持生命健康中发挥着至关重要的作用。横纹肌(骨骼肌和心肌)作为人体的重要组成部分,承担着能量代谢、姿势维持以及推动血液流动等多重功能,对维持机体生命活动至关重要;当横纹肌代谢紊乱时,可能引发一系列横纹肌疾病,如骨骼肌萎缩和心肌肥大等。近年来研究显示,SIRT6参与横纹肌相关功能调控。本综述旨在深入探讨SIRT6在横纹肌生理和病理状态下的调控机制及其生理功能,以期为相关领域的基础研究和疾病防治提供新的思路和策略。

关键词： SIRT6 横纹肌骨骼肌心肌生理状态病理状态

Metal/nanocarbon layer current collectors enhanced energy efficiency in lithium-sulfur batteries

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Science Bulletin 2017年第18期62卷 1267-1274页

作者： Jia-Qi Huang Pei-Yan Zhai Hong-Jie Peng wan-Cheng Zhu qiang Zhang Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical Engineering Tsinghua University Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Department of Chemical Engineering Qufu Normal University

Lithium-sulfur （Li-S） batteries with intrinsic merits in high theoretical energy density are the most promising candidate as the next-generation power sources. The strategy to achieve a high utilization of active materials with high energy efficiency is strongly requested for practical applications with less energy loss during repeated cycling. In this contribution, a metal/nanocarbon layer current collector is proposed to enhance the redox reactions of polysulfides in a working Li-S cell. Such a concept is demon- strated by coating graphene-carbon nanotube hybrids （GNHs） on routine aluminum （AI） foil current collectors. The interracial conductivity and adhesion between the current collector and active material are significantly enhanced. Such novel cell configuration with metal/nanocarbon layer current collectors affords abundant Li ions for rapid redox reactions with small overpotential. Consequently, the Li-S cells with nanostructured current collectors exhibit an initial discharge capacity of 1,113 mAh g-1 at 0.5 C, which is -300 mAh g-1 higher than those without a GNH coating layer. The capacity retention is 73% for cells with GNH after 300 cycles. A reduced voltage hysteresis and a high energy efficiency of ca. 90% are therefore achieved. Moreover, the AI/GNH layer current collectors are easily implanted into current cell assembly process for energy storage devices based on complex multi-electron redox reactions （e.g., Li-S batteries, Li-O2 batteries, fuel cells, and flow batteries）.

关键词： Lithium-sulfur battery Nanostructured current collectors Polysulfides Energy efficiency Pouch cell

Synthesis of 5-vinyl-2-norbornene through Diels-Alder reaction of cyclopentadiene with 1,3-butadiene in supercritical carbon dioxide

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Chinese Chemical Letters 2017年第4期28卷 900-904页

作者： Fan-qiang Meng Xiu-Juan Feng wan-Hui wang Ming Bao State Key Laboratory of Fine Chemicals Dalian University of Technology Dalian 116023 China School of Petroleum and Chemical Engineering Dalian University of Technology Panjin 124221 China

An efficient method for the synthesis of 5-vinyl-2-norbornene from cyclopentadiene and 1,3-butadiene was *** Diels-Alder reaction of cyclopentadiene with 1,3-butadiene proceeded smoothly in supercritical carbon dioxide in the absence of any polymerization inhibitor to produce the corresponding5-vinyl-2-norbornene in satisfactory yield with high selectivity.

关键词： 5-Vinyl-2-norbornene Diels-Alder reaction Cyclopentadiene 1 3-Butadiene Supercritical carbon dioxide

Spatial Pattern Evolution and Casual Analysis of County Level Economy in Changsha-Zhuzhou-Xiangtan Urban Agglomeration, China

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Chinese Geographical Science 2014年第5期24卷 620-630页

作者： DONG Minghui ZOU Bin PU qiang wan Neng YANG Lingbin LUO Yanqing Department of Geography Hunan University of Arts and Science Department of Geomatics and Remote Sensing Central South University Department of Geography University of Utah Department of Geography Northeast Normal University

In order to evaluate whether or not the county units′ economy in the Changsha-Zhuzhou-Xiangtan(Chang-Zhu-Tan) Urban Agglomeration was growing as expected, this study analyzed the spatial economy pattern at county-level by using the Exploratory Spatial Data Analysis(ESDA) method. In this process, the global Moran′s I and local Getis-Ord G*i indexes were employed to analyze indicators including per capita GDP and three industrials(i.e. primary, secondary and tertiary industry) from 2000 to 2010. The results show that: 1) the county units′ economy in the Chang-Zhu-Tan Urban Agglomeration has exhibited a strong spatial autocorrelation and an accelerated integration trend since 2008(Moran′ s I increased from 0.26 to 0.56); 2) there is a significant difference in economy development between the northern and southern county units in the Chang-Zhu-Tan Urban Agglomeration: the hotspot zone with high economic level was formed among the northern county units whereas the coldspot zone with low economic level was located in the southern areas. This difference was caused primarily by the increasingly prominent economic radiation effect of Changsha ′upheaval′; 3) town density, secondary industry, and the integration policy are the major contributors driving the evolution of the spatial economy pattern in the Chang-Zhu-Tan Urban Agglomeration.

关键词： spatial autocorrelation spatial heterogeneity urban agglomeration county-level economy Changsha-Zhuzhou-Xiangtan (Chang-Zhu-Tan), China

Coding metamaterials, digital metamaterials and programmable metamaterials

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Light(Science & Applications) 2014年第1期3卷 27-35页

作者： Tie Jun Cui Mei Qing Qi Xiang wan Jie Zhao qiang Cheng State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Cooperative Innovation Centre of Terahertz Science University of Electronic Science and TechnologyChengdu 611731China

Metamaterials are artificial structures that are usually described by effective medium parameters on the macroscopic scale,and these metamaterials are referred to as‘analog metamaterials’.Here,we propose‘digital metamaterials’through two ***,we present‘coding metamaterials’that are composed of only two types of unit cells,with 0 and p phase responses,which we name‘0’and‘1’elements,*** coding‘0’and‘1’elements with controlled sequences(i.e.,1-bit coding),we can manipulate electromagnetic(EM)waves and realize different *** concept of coding metamaterials can be extended from 1-bit coding to 2-bit coding or *** 2-bit coding,four types of unit cells,with phase responses of 0,p/2,p,and 3p/2,are required to mimic the‘00’,‘01’,‘10’and‘11’elements,*** 2-bit coding has greater freedom than 1-bit coding for controlling EM ***,we propose a unique metamaterial particle that has either a‘0’or‘1’response controlled by a biased *** on this particle,we present‘digital metamaterials’with unit cells that possess either a‘0’or‘1’*** a field-programmable gate array,we realize digital control over the digital *** programming different coding sequences,a single digital metamaterial has the ability to manipulate EM waves in different manners,thereby realizing‘programmable metamaterials’.The above concepts and physical phenomena are confirmed through numerical simulations and experiments using metasurfaces.

关键词： coding digital metamaterial metasurface programmable