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Trajectory compensation for multi-robot coordinated lifting system considering elastic catenary of the rope

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High Technology Letters 2024年第3期30卷 252-262页

作者： zhao Xiangtang zhao zhigang SU Cheng MENG Jiadong WANG Baoxi School of Mechanical Engineering Lanzhou Jiaotong UniversityLanzhou 730070P.R.China

The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible *** deformation of the flexible rope causes errors in the movement trajectory of the lifting *** on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is *** to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and *** the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible *** trajectoy of the lifting system considering the deformation of flexible *** results show that the mass and elasticity of the flexible rope can not be ***,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation *** research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。

关键词： multi-robot lifting system deformation of flexible rope elastic catenary model compensation principle of position and posture trajectory compensation

Genetic and molecular mechanisms of reproductive isolation in the utilization of heterosis for breeding hybrid rice

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Journal of Genetics and Genomics 2024年第6期51卷 583-593页

作者： Chaolong Wang Xiaowen Yu Jian Wang zhigang zhao Jianmin Wan State Key Laboratory for Crop Genetics&Germplasm Enhancement and Utlization Nanjing Agricultural UniversityZhongshan Biological Breeding LaboratoryNanjingJiangsu210095China State Key Laboratory of Crop Gene Resources and Breeding Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China

Heterosis,also known as hybrid vigor,is commonly observed in rice *** hybridization of rice species or subspecies exhibits robust hybrid vigor,however,the direct harnessing of this vigor is hindered by reproductive ***,we review recent advances in the understanding of the molecular mechanisms governing reproductive isolation in inter-subspecific and inter-specific *** review encompasses the genetic model of reproductive isolation within and among Oryza sativa species,emphasizing the essential role of mitochondria in this ***,we delve into the molecular intricacies governing the interaction between mitochondria and autophagosomes,elucidating their significant contribution to reproductive ***,our exploration extends to comprehending the evolutionary dynamics of reproductive isolation and speciation in *** on these advances,we offer a forward-looking perspective on how to overcome the challenges of reproductive isolation and facilitate the utilization of heterosis in future hybrid rice breeding endeavors.

关键词： Hybrid vigor Reproductive isolation Hybrid ricebreeding

U-Pb zircon ages and petrogeochemistry and tectonic implications of gabbro and granite in southwest Lahad Datu area of Sabah, Malaysia

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Acta Oceanologica Sinica 2024年第2期43卷 94-110页

作者： zhigang zhao Wu Tang Shixiang Liu Huafeng Tang Pujun Wang Zhiwen Tian China National Offshore Oil Corporation(CNOOC)Research Institute Co. Ltd.Beijing 100028China College of Earth Sciences Jilin UniversityChangchun 130061China

The southwest Lahad Datu felsic rocks were previously thought to have formed in the late Triassic as part of the microcontinental crystalline *** on U-Pb ages,geochemistry,and the Hfisotopes of zircon from the southeastern Sabah gabbro and granite,in this study,the tectonic properties of the Sabah area during the Triassic were *** weighted average U-Pb zircon ages of the gabbro and granite samples were determined to be(230.9±2.5)Ma and(207.1±3.3)Ma,*** granite had SiO_(2) contents of 66.54%-79.47%,low TiO_(2) contents of 0.08%-0.3%,Al_(2)O_(3) contents of 10.97%-16.22%,Na_(2)O contents of 5.91 %-6.39%,and low K_(2)O contents of 0.15%-0.65%.The chondrite-normalized rare earth element(REE) patterns exhibit light REE enrichment,with right-sloping *** primitive mantle-normalized trace element spider diagrams exhibit Th,U,La,Sr,and Zr enrichment and Nb,Ta,P and Ti depletions,i.e.,the geochemical characteristics of typical island arc igneous *** tectonic discriminant diagram indicates that the granite is a volcanic arc *** Hf isotopic an alysis of gabbro zircon revealed that the zircons have ε_(Hf)(t)values of 12.08-16.24(mean of 14.32) and two-stage model ages(t_(DM2)) of 223-491 Ma(mean of 347 Ma).This indicates that the diagenetic magma of the gabbro was mainly derived from melting of newly formed crustal *** ophiolite in southeast Sabah has existed since the early Late *** crystalline basement granite in southeastern S abah was emplaced lasted from late Triassic to early *** on previous studies and global plate reconstruction models,it is speculated that the southeastern Sabah granite may have been formed in an island arc setting,i.e.,where the oceanic crust of the Paleo-Tethys Ocean collided with the oceanic crust of the Panthalassa Ocean.

关键词： Sabah early late Triassic ophiolite granite tectonic properties

Decoupled knowledge distillation method based on meta-learning

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High-Confidence Computing 2024年第1期4卷 1-6页

作者： Wenqing Du Liting Geng Jianxiong Liu zhigang zhao Chunxiao Wang Jidong Huo Key Laboratory of Computing Power Network and Information Security Ministry of EducationShandong Computer Science Center(National Supercomputer Center in Jinan)Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China Shandong Provincial Key Laboratory of Computer Networks Shandong Fundamental Research Center for Computer ScienceJinan 250014China Aerospace Science&Industry Network Information Development Co. LTDBeijing 100854China

With the advancement of deep learning techniques,the number of model parameters has been increasing,leading to significant memory consumption and limits in the deployment of such models in real-time *** reduce the number of model parameters and enhance the generalization capability of neural networks,we propose a method called Decoupled MetaDistil,which involves decoupled *** method utilizes meta-learning to guide the teacher model and dynamically adjusts the knowledge transfer strategy based on feedback from the student model,thereby improving the generalization ***,we introduce a decoupled loss method to explicitly transfer positive sample knowledge and explore the potential of negative samples *** experiments demonstrate the effectiveness of our method.

关键词： Model compression Knowledge distillation Meta-learning Decoupled loss

Tree allometry responses to competition and complementarity in mixed-species plantations of Betula alnoides

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Forest Ecosystems 2024年第4期11卷 469-479页

作者： Boyao Chen Kaili Liu Chunsheng Wang Junjie Guo Junkun Lu Lin Chen zhigang zhao Jie Zeng Research Institute of Tropical Forestry Chinese Academy of ForestryGuangzhou510520China Central South University of Forestry&Technology Changsha410004China Experimental Center of Tropical Forestry Chinese Academy of ForestryPingxiang532600China Nanjing Forestry University Nanjing210037China

Tree allometry plays a crucial role in tree survival,stability,and timber quantity and quality of mixed-species ***,the responses of tree allometry to resource utilisation within the framework of interspecific competition and complementarity remain poorly *** into consideration strong-and weakspace competition(SC and WC),as well as N_(2)-fixing and non-N_(2)-fixing tree species(FN and nFN),a mixedspecies planting trial was conducted for Betula alnoides,a pioneer tree species,which was separately mixed with Acacia melanoxylon(SC+FN),Erythrophleum fordii(WC+FN),Eucalyptus cloeziana(SC+nFN)and Pinus kesiya ***(WC+nFN)in southern *** years after planting,tree growth,total nitrogen(N)and carbon(C)contents,and the natural abundances of^(15)N and^(13)C in the leaves were measured for each species,and the mycorrhizal colonisation rates of *** were investigated under each *** variations and their relationships with space competition and nutrient-related factors were *** results showed a consistent effect of space competition on the height-diameter relationship of *** in mixtures with FN or *** tree height growth of *** was significantly promoted under high space competition,and growth in diameter at breast height(DBH),tree height and crown size were all expedited in mixtures with *** symbiotic relationship between ectomycorrhizal fungi and *** was significantly influenced by both space competition and N_(2) fixation by the accompanying tree species,whereas such significant effects were absent for arbuscular mycorrhizal ***,high space competition significantly decreased the water use efficiency(WUE)of ***,and its N use efficiency(NUE)was much lower in the FN *** equation modeling further demonstrated that the stem allometry of *** was affected by its NUE and WUE via changes in its height growth,and crown allometry was influ

关键词： Allometric relationship Resources competition and complementarity Mixed-species forest Tree-fungal symbiotic relationship N_2-fixing tree species Resource utilisation strategies

Trajectory planning for multi-robot coordinated towing system based on stability

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High Technology Letters 2024年第1期30卷 43-51页

作者：赵志刚 zhao Xiangtang WEI Qizhe SU Cheng MENG Jiadong School of Mechanical Engineering Lanzhou Jiaotong UniversityLanzhou 730070P.R.China

Given the unconstrained characteristics of the multi-robot coordinated towing system,the rope can only provide a unidirectional constraint force to the suspended object,which leads to the weak ability of the system to resist external disturbances and makes it difficult to control the trajectory of the suspended *** on the kinematics and statics of the multi-robot coordinated towing system with fixed base,the dynamic model of the system is established by using the Newton-Euler equations and the Udwadia-Kalaba *** plan the trajectories with high stability and strong control,trajectory planning is performed by combining the dynamics and stability of the towing *** on the dynamic stability of the motion trajectory of the suspended object,the stability of the suspended object is effectively improved through online real-time planning and offline manual *** effectiveness of the proposed method is verified by comparing the motion stability of the suspended object before and after *** results provide a foundation for the motion planning and coordinated control of the towing system.

关键词： towing system unconstrained system trajectory planning dynamic stability

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多机协调吊运系统点到点轨迹规划策略研究

机械强度 2024年第3期46卷 675-684页

作者：李涛赵志刚朱明同赵祥堂兰州交通大学机电工程学院兰州730070

针对速度与加速度不连续的被吊运物轨迹不能直接运用于多机器人协调吊运系统的逆运动学求解问题,提出一种基于点到点轨迹规划的逆运动学求解策略。首先,建立了该系统运动学与动力学模型。然后,对系统的逆运动学进行了分析,并对不同解的... 详细信息

针对速度与加速度不连续的被吊运物轨迹不能直接运用于多机器人协调吊运系统的逆运动学求解问题,提出一种基于点到点轨迹规划的逆运动学求解策略。首先,建立了该系统运动学与动力学模型。然后,对系统的逆运动学进行了分析,并对不同解的情况给出了解决办法。随后,提出了基于点到点轨迹规划求解可行逆解的策略,利用三种代数规划方法对被吊运物轨迹进行规划,在保证规划后的速度与加速度连续的基础上,结合逆运动学不同解的处理办法,得到更具有普适意义的可行逆解。最后,通过两个实例仿真验证了该策略的可行性,且只有五次多项式规划法符合拉力条件,研究结果为系统张力优化分布和控制奠定了基础。

关键词：欠约束多机器人系统吊运系统点到点轨迹规划逆运动学

考虑PWM波形特征的纳米晶磁心损耗模型的研究及验证

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电工技术学报 2024年第6期39卷 1602-1612页

作者：赵志刚贾慧杰刘朝阳赵安琪高鹏旭省部共建电工装备可靠性与智能化国家重点实验室(河北工业大学) 天津300401 河北省电磁场与电器可靠性重点实验室(河北工业大学) 天津300401

磁心损耗精确预测对于电力电子变压器的优化设计至关重要。然而,传统的磁心损耗模型在复杂激励下适用性较差,尤其对于占空比可调、高次谐波含量丰富的PWM波磁心损耗预测,计算精度显著下降。基于Jordan损耗分离模型,建立了一种考虑PWM波... 详细信息

磁心损耗精确预测对于电力电子变压器的优化设计至关重要。然而,传统的磁心损耗模型在复杂激励下适用性较差,尤其对于占空比可调、高次谐波含量丰富的PWM波磁心损耗预测,计算精度显著下降。基于Jordan损耗分离模型,建立了一种考虑PWM波形特征的磁心损耗计算方法。首先,该方法根据激励波形特征,推导出相应的波形系数及等效频率来计算PWM波激励下的动态涡流损耗,将Jordan模型的适用范围从正弦拓展到PWM波激励下的磁心损耗计算;然后,分析了不同占空比激励下激励波形有效频率及高次谐波含量变化对损耗系数的影响,并对其进行数学表征,实现了整个占空比范围内磁心损耗的精确预测;最后,搭建了高频非正弦激励下软磁材料磁特性测量平台,针对1K107B纳米晶材料,测量了两种典型PWM波激励下的损耗数据。实验结果表明,所建立的磁心损耗模型具有较高的计算精度,相比于传统的Steinmetz改进公式,整体精度提高了25%。

关键词：纳米晶磁心损耗 PWM波形特征 Jordan模型

基于等效复数磁导率的利兹线绕组损耗计算模型

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电工技术学报 2024年第4期39卷 947-955页

作者：赵志刚王丽美陈天缘赵安琪卢子奇省部共建电工装备可靠性与智能化国家重点实验室(河北工业大学) 天津300401 河北省电磁场与电器可靠性重点实验室(河北工业大学) 天津300401

绕组损耗是高频变压器总体损耗的重要组成部分,是影响磁性元件体积、效率和温升的关键性参数。由于利兹线的高频损耗小而广泛应用于高频变压器绕组,但其复杂的三维扭转结构导致准确、快速地计算绕组损耗十分困难。解析方法需要进行简化... 详细信息

绕组损耗是高频变压器总体损耗的重要组成部分,是影响磁性元件体积、效率和温升的关键性参数。由于利兹线的高频损耗小而广泛应用于高频变压器绕组,但其复杂的三维扭转结构导致准确、快速地计算绕组损耗十分困难。解析方法需要进行简化和近似处理,难以准确地表征绕组的高频涡流特性,有限元数值方法需要对每匝绕组精细化建模,导致计算资源耗费严重。采用具有等效复值材料特性的区域替代绕组区域的均匀化技术,能够实现二维磁场对涡流效应的表征,降低了精细化建模的计算成本。但等效区域的材料特性需要利用数值方法获得,增加了计算的复杂性。因此该文通过分析利兹线损耗机理,考虑利兹线截面形状对等效区域材料特性的影响,实现了圆形利兹线绕组等效复数磁导率的明确解析描述。建立了圆形利兹线绕组损耗计算模型,验证了等效复数磁导率计算邻近效应的准确性,实现了较宽频率范围内绕组损耗的准确预测。

关键词：利兹线绕组损耗等效复数磁导率趋肤效应邻近效应