检索结果-南通市图书馆

Dynamic motion of quadrupedal robots on challenging terrain:a kinodynamic optimization approach

Frontiers of Mechanical Engineering 2024年第3期19卷 23-40页

作者： qi LI Lei ding Xin LUO Engineering Research Center of Hubei Province for Clothing Information Wuhan 430200China School of Computer Science and Artificial Intelligence Wuhan Textile UniversityWuhan 430200China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The dynamic motion of quadrupedal robots on challenging terrain generally requires elaborate spatial–temporal kinodynamic motion planning and accurate control at higher refresh rate in comparison with regular ***,conventional quadrupedal robots usually generate relatively coarse planning and employ motion replanning or reactive strategies to handle terrain *** resultant complex and computation-intensive controller may lead to nonoptimal motions or the breaking of locomotion *** this paper,a kinodynamic optimization approach is *** generate long-horizon optimal predictions of the kinematic and dynamic behavior of the quadruped robot on challenging terrain,we formulate motion planning as an optimization problem;jointly treat the foot’s locations,contact forces,and torso motions as decision variables;combine smooth motion and minimal energy consumption as the objective function;and explicitly represent feasible foothold region and friction constraints based on terrain *** track the generated motions accurately and stably,we employ a whole-body controller to compute reference position and velocity commands,which are fed forward to joint controllers of the robot’s *** verify the effectiveness of the developed approach through simulation and on a physical quadruped robot *** show that the quadruped robot can successfully traverse a 30°slope and 43% of nominal leg length high step while maintaining the rhythm of dynamic trot gait.

关键词： quadrupedal robot kinodynamic planning nonlinear optimization challenging terrain whole-body control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rapid growth of ZnO hexagonal tubes by direct microwave heating

引用

International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 80-85页

作者： Zhen-qi zhu Jian Zhou School of Materials Science and Technology Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Zinc oxide hexagonal tubular crystals were synthesized by direct microwave heating from ZnO powders within 5 min without any metal catalysts or transport agents. ZnO source materials were evaporated from the high-temperature zone in an enclosure, and crystals were grown on the self-source substrate in an appropriate condition. The ZnO vapor formed in the high-temperature zone can deposit and grow on the powders located in the low-temperature zone to form crystals. The scanning electron microscopy （SEM） reveals that these products are hexagonal tube crystals with 80 ~rn in diameter and 250 μm in length, having a well faceted end and side surface. A possible growth mechanism and the influence of reaction temperature on the formation of crystalline ZnO hexagonal tubes were presented. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating the potential applications in short-wave light-emitting photonic devices.

关键词： ZnO crystal microwave heating vapor growth photoluminescence (PL)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Based on point merge for paired approach sequencing on closely spaced parallel runways

引用

Journal of Traffic and Transportation Engineering(English Edition) 2023年第5期10卷 934-946页

作者： Laijun Wang qi ding Dongxuan Wei College of Transportation Engineering Chang'an UniversityXi'an 710064China

The paired approach is a kind of efficiency approach to closely spaced parallel runways(CSPRs),and the point merge system has the powerful interval management function,which is effective to realize the converge of traffic flows from different approach *** order to improve the operation efficiency of the airport terminal area,a model of paired approach sequencing based on point merge is proposed to investigate the problem of increasing the operation capacity of the closely spaced parallel *** the minimum average flight delay time as the objective,the flight distance on sequencing legs,wake turbulence separation and paired approach safety separation as constraints,the genetic algorithm is used to optimize the paired approach sequencing of arrival *** the closely parallel runways of Shanghai Hongqiao International Airport run south as an example,the point merge program is designed and the effect of model was *** results show that after optimization,the average delay time and average landing time are reduced by 40.6%and 51.8%respectively,the capacity of the closely spaced parallel runways are 1.1 times higher than the actual,the flight uptime rate can reach 100%.It is concluded that the proposed model is feasible,which can effectively reduce delay times and alleviate congestion in terminal areas.

关键词： Air traffic management Sequence of arrival flights Point merge Closely spaced parallel runway Paired approach Genetic algorithm

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Radical SAM-Dependent Demetallation of Heme

引用

Chinese Journal of Chemistry 2022年第9期40卷 1053-1058页

作者： Jinduo Cheng Wei ding qi Zhang Department of Chemistry Fudan UniversityShanghai 200433China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China

Demetallation of heme to release iron is a chemical difficult reaction and is highly rare in biochemistry,with apoferritin as the only known enzyme responsible for this *** we show the heme degradation enzyme Chuw catalyzes heme demetallation besides its known methyltransferase activity(which converts heme to a ring-open product anaerobilin).We show the demetallation activity of Chuw is radical SAM-dependent,and likely involves the same set of intermediates involved in the anaerobilin-producing *** ChuW-catalyzed demetallation reaction does not require external reductant,and can occur on several heme analogs with different metal *** findings establish a brand-new chemistry in the radical SAM enzymes,highlighting the remarkable catalytic diversity of this superfamily of enzymes.

关键词： Biosynthesis Biotransformations Cofactors Enzymes Hemin

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Consecutive Methylation Catalyzed by TsrM,an Atypical Class B Radical SAM Methylase

引用

Chinese Journal of Chemistry 2022年第14期40卷 1693-1698页

作者： Runze Wu Wei ding qi Zhang Department of Chemistry Fudan UniversityShanghai 200433China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai200240China

TsrM is a cobalamin-dependent radical S-adenosylmethionine(SAM)methyltransferase belonging to the Class B radical SAM methylase(RSM)*** enzyme catalyzes the C-2 methylation of L-tryptophan to produce 2-methyltrytophan(2-MeTrp),an intermediate involved in the biosynthesis of thiostrepton *** this work,we report characterization of an unexpected activity of TsrM,which carries out an additional methylation reaction on the product 2-MeTrp.A series of isotopic labeling studies and assays with different Trp analogs revealed that TsrM is able to transfer a methyl group from SAM to the C4 of 2-MeTrp to produce 2,*** results reveal the intriguing substrate specificity of TsrM,further expanding the reaction promiscuity of the radical SAM superfamily enzymes.

关键词： Biosynthesis Biotransformations Catalytic promiscuity Enzyme Methyltransferase

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Characterization of HpnG as a Purine Nucleoside Phosphorylase in Bacteriohopanepolyol Biosynthesis

引用

Chinese Journal of Chemistry 2024年第19期42卷 2351-2356页

作者： Xinhui Li Xiaoyu zhu Yuting Zhong Wei Zhang Fener Chen Wenning Wang Wei ding qi Zhang Department of Chemistry Fudan UniversityShanghai 200433China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 73000China

Comprehensive Summary HpnG plays a crucial role in the production of ribosylhopane,a key intermediate in the biosynthesis of *** early extensive studies,the precise function of HpnG has remained ***,we report functional characterization of HpnG as a purine nucleoside phosphorylase,which converts adenosylhopane to phosphoribosylhopane in the presence of *** demonstrates broad substrate specificity and impressive stability,making it a valuable enzymatic tool for applications in nucleoside processing and related biotechnology.

关键词： Enzymes Enzyme catalysis Nucleosides Biosynthesis Natural products Lipids Phosphorolysis Biotransformations

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Arbitrariness of the general solution of the partial differential equations and its applications

引用

Science China Mathematics 2010年第7期53卷 1729-1739页

作者： ding qi Zhang Hongqing Dalian Univ Technol Sch Math Sci Dalian 116024 Peoples R China

Using the framework of formal theory of partial differential equations, we consider a method of computation of the bi-Hilbert polynomial (i.e. Hilbert polynomial in two variables). Furthermore, present an approach to compute the number of arbitrary functions of positive differential order in the general solution. Then, under the "AC=BD" model for mathematics mechanization developed by Hong-qing ZHANG, we present a method to reduce an overdetermined system to a well-determined one. As applications, the Maxwell equations and weakly overdetermined equations are considered.

关键词： 'AC=BD' model involution Hilbert polynomial arbitrariness overdetermined

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Parallel Finite Element Algorithm for the Unsteady Oseen Equations

引用

Advances in Applied Mathematics and Mechanics 2021年第6期13卷 1501-1519页

作者： qi ding Yueqiang Shang School of Mathematics and Statistics Southwest UniversityChongqing 400715China Tongnan Middle School Chongqing 402660China

Based on fully overlapping domain decomposition,a parallel finite element algorithm for the unsteady Oseen equations is proposed and *** this algorithm,each processor independently computes a finite element approximate solution in its own subdomain by using a locally refined multiscale mesh at each time step,where conforming finite element pairs are used for the spatial discretizations and backward Euler scheme is used for the temporal discretizations,*** subproblem is defined in the entire domain with vast majority of the degrees of freedom associated with the particular subdomain that it is responsible for and hence can be solved in parallel with other subproblems using an existing sequential solver without extensive *** algorithm is easy to implement and has low communication *** bounds of the parallel finite element approximate solutions are *** experiments are also given to demonstrate the effectiveness of the algorithm.

关键词： Oseen equations finite element overlapping domain decomposition backward Euler scheme parallel algorithm

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A New Interpretation of S-Transform Spectrum:Phase Hopping Analysis and Estimation

引用

Chinese Journal of Electronics 2019年第2期28卷 338-343页

作者： zhu Mingzhe qi Yue ZHANG Xinliang School of Electronic Engineering Xidian University

S-Transform(ST) is a powerful timefrequency analysis tool with several useful *** has been found that ST is sensitive to the sudden change of signal phase and causes a spectrum spread phenomenon,which is often regarded as a shortage. However, a new interpretation of ST spectrum is proposed: the ST can provide a better property of phase hopping detection due to the sensitivity and mono-peak response of ST *** is a beneficial method to phase hopping estimation. The mathematical relation between the phase hopping angle and the instantaneous value changes of ST spectrum is derived in an explicit representation. This work helps to make a better understanding of the ST spectrum. Besides of the formula derivation, the characteristic is also proved and confirmed by the numerical simulations.

关键词： S-Transform(ST) Phase hopping Frequency spectrum spread

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Robust Estimation for Poisson Integer-Valued GARCH Models Using a New Hybrid Loss

引用

Journal of Systems Science & Complexity 2021年第4期34卷 1578-1596页

作者： LI qi CHEN Huaping zhu Fukang College of Mathematics Changchun Normal UniversityChangchun 130032China School of Mathematics and Statistics Henan UniversityKaifeng 475004China School of Mathematics Jilin UniversityChangchun 130012China

The Poisson integer-valued GARCH model is a popular tool in modeling time series of *** commonly used maximum likelihood estimator is strongly influenced by outliers,so there is a need to develop a robust M-estimator for this *** paper has three ***,the authors propose a new loss function,which is a hybrid of the tri-weight loss for relatively small errors and the exponential squared loss for relatively large ***,Mallows’quasi-likelihood estimator(MQLE)is proposed as an M-estimator and its existence,uniqueness,consistency and asymptotic normality are *** addition,a data-adaptive algorithm for computing MQLE is given based on a datadriven selection of tuning parameters in the loss ***,simulation studies and analysis of a real example are conducted to illustrate the performance of the new estimator,and a comparison with existing estimators is made.

关键词： Loss function M-estimation time series of counts tuning parameter

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：