Small-scale rotorcraft unmanned robotic systems(SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relati...Small-scale rotorcraft unmanned robotic systems(SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relative research in the future. In the past decade, aerial manipulation of SRURSs has attracted the interest of researchers globally. This paper provides a literature review of the last 10 years(2008–2017) on SRURSs, and details achievements and challenges. Firstly, the definition, current state, development, classification, and challenges of SRURSs are introduced. Then, related papers are organized into two topical categories: mechanical structure design, and modeling and control. Following this, research groups involved in SRURS research and their major achievements are summarized and classified in the form of tables. The research groups are introduced in detail from seven parts. Finally, trends and challenges are compiled and presented to serve as a resource for researchers interested in aerial manipulation of SRURSs. The problem,trends, and challenges are described from three aspects. Conclusions of the paper are presented,and the future of SRURSs is discussed to enable further research interests.展开更多
This paper investigates the production of pure aluminum by using traditional metallurgy and nanotechnology. To make a pure aluminum stronger, extremely cold and mechanical manipulation process was employed and followe...This paper investigates the production of pure aluminum by using traditional metallurgy and nanotechnology. To make a pure aluminum stronger, extremely cold and mechanical manipulation process was employed and followed by carefully heat treatment cycle. The practical produetion and testing showed that the higher the stored dislocation＇s density after rolling was, the finer the recrystallized grains during heating were. In aluminum, these new grains were only a couple of nanometers in size, several hundred times smaller than the original crystals, making the aluminum much stronger than its original form.展开更多
It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV)spin at the single-quantum level with a microwave(MW)cavity.As an alternative,a hybrid system with the spin–phonon–photon triple i...It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV)spin at the single-quantum level with a microwave(MW)cavity.As an alternative,a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is proposed.According to the general mechanical parametric amplification of this in-between phonon mode,the direct spin–phonon and photon–phonon couplings are both exponentially enhanced,which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher efficiency.In view of this triple system with enhanced couplings and the additional sideband adjustable designs,this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin coherently.It is also hoped to evoke wider applications in the areas of quantum state transfer and preparation,ultrasensitive detection and quantum nondestructive measurement,etc.展开更多
The mechanical stability of tRNAs contributes to their biological activities.The mitochondrial tRNAArg from Romanomermis culicivorax is the shortest tRNA ever known.This tRNA lacks D-and T-arms,represents a stem-bulge...The mechanical stability of tRNAs contributes to their biological activities.The mitochondrial tRNAArg from Romanomermis culicivorax is the shortest tRNA ever known.This tRNA lacks D-and T-arms,represents a stem-bulge-stem architecture but still folds into a stable tertiary structure.Although its structure had been reported,studies on its mechanical folding and unfolding kinetic characteristics are lacking.Here,we directly measured the single-molecule mechanical folding and unfolding kinetics of the armless mt tRNAArg by using optical tweezers in different solution conditions.We revealed a two-step reversible unfolding pathway:the first and large transition corresponds to the unfolding of acceptor stem and bulge below 11 pN,and the second and small transition corresponds to the unfolding of anticodon arm at 12 pN-14 pN.Moreover,the free energy landscapes of the unfolding pathways were reconstructed.We also demonstrated that amino acid-chelated Mg^(2+)(aaCM),which mimics the intracellular solution condition,stabilizes the bulge of mitochondrial tRNAArg possibly by reducing the topological constraints or stabilizing the possible local non-canonical base pairings within the bulge region.Our study revealed the solution-dependent mechanical stability of an armless mt tRNA,which may shed light on future mt tRNA studies.展开更多
声学黑洞(acoustic black hole,ABH)效应是利用薄壁结构几何参数或者材料特性参数的梯度变化,使波在结构中的传播速度逐渐减小,理想情况下波速减小至零从而不发生反射的现象.实现声学黑洞效应的主要方法是将薄板结构的厚度按照一定规律...声学黑洞(acoustic black hole,ABH)效应是利用薄壁结构几何参数或者材料特性参数的梯度变化,使波在结构中的传播速度逐渐减小,理想情况下波速减小至零从而不发生反射的现象.实现声学黑洞效应的主要方法是将薄板结构的厚度按照一定规律裁剪,利用声学黑洞可以将结构中传播的波动能量聚集在特定的位置.声学黑洞对波的聚集具有宽频高效、实现方法简单灵活等特点,在薄壁结构的减振降噪、能量回收等应用中具有明显的优势.本文介绍声学黑洞效应的基本原理、相关力学问题的研究进展和有待进一步探究的问题,包括声学黑洞结构的建模与分析方法、实验研究方法及进展、声学黑洞结构中波的传播与操控,以及声学黑洞在工程应用中的相关问题.展开更多
微机电系统(M EM S)以飞快的速度发展成为一个集微型机械、微传感器、微能源、微致动器、微控制器、微执行器、信号处理和智能控制于一体的新兴研究领域。微机电系统结构的复杂性促进了微装配技术的蓬勃发展,吸引了大批国内外研究人员...微机电系统(M EM S)以飞快的速度发展成为一个集微型机械、微传感器、微能源、微致动器、微控制器、微执行器、信号处理和智能控制于一体的新兴研究领域。微机电系统结构的复杂性促进了微装配技术的蓬勃发展,吸引了大批国内外研究人员对其进行广泛研究。本文首先分析了微器件装配技术对微机电系统的重要性及其产生的深远影响,然后介绍了近年来国内微装配技术的发展现状和参与微装配项目研发的研究单位的一些有应用价值的研究成果,最后阐述了微装配系统的发展趋势。展开更多
A 6-DOF micro-manipulation robot based on a 3-PPTTRS mechanism is proposed in this paper.Its static stiffness is an important index to evaluate load capacity and positioning accuracy.However,it is insufficient to cons...A 6-DOF micro-manipulation robot based on a 3-PPTTRS mechanism is proposed in this paper.Its static stiffness is an important index to evaluate load capacity and positioning accuracy.However,it is insufficient to consider the static stiffness only when the robot is in its initial pose.The stiffness in different positions and poses in its work space must be analyzed also.Thus a method to analyze the relationship between static stiffness and poses in the whole work space is presented.A static stiffness model is proposed first,and the relationship between structural parameters and static stiffness in different poses is discussed.The static stiffness analysis provides foundation for structural parameter design.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 91748201 and 51505014)
文摘Small-scale rotorcraft unmanned robotic systems(SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relative research in the future. In the past decade, aerial manipulation of SRURSs has attracted the interest of researchers globally. This paper provides a literature review of the last 10 years(2008–2017) on SRURSs, and details achievements and challenges. Firstly, the definition, current state, development, classification, and challenges of SRURSs are introduced. Then, related papers are organized into two topical categories: mechanical structure design, and modeling and control. Following this, research groups involved in SRURS research and their major achievements are summarized and classified in the form of tables. The research groups are introduced in detail from seven parts. Finally, trends and challenges are compiled and presented to serve as a resource for researchers interested in aerial manipulation of SRURSs. The problem,trends, and challenges are described from three aspects. Conclusions of the paper are presented,and the future of SRURSs is discussed to enable further research interests.
文摘This paper investigates the production of pure aluminum by using traditional metallurgy and nanotechnology. To make a pure aluminum stronger, extremely cold and mechanical manipulation process was employed and followed by carefully heat treatment cycle. The practical produetion and testing showed that the higher the stored dislocation＇s density after rolling was, the finer the recrystallized grains during heating were. In aluminum, these new grains were only a couple of nanometers in size, several hundred times smaller than the original crystals, making the aluminum much stronger than its original form.
基金supported by the National Natural Science Foundation of China under Grants No.11774285,No.11774282,and No.11504102the Natural Science Foundation of Hubei Province under Grants No.2020CFB748,and No.2019CFB788+2 种基金the Research Project of Hubei Education Department under Grants No.D20201803,No.B2020079,and No.B2020078the Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(HUAT)under Grants No.BK201906,and No.BK202008the Foundation of Discipline Innovation Team of HUAT.H.T.R.is supported by the the Doctoral Scientific Research Foundation of Liaocheng University under Grant No.318052054。
文摘It remains a great challenge to realize direct manipulation of a nitrogen-vacancy(NV)spin at the single-quantum level with a microwave(MW)cavity.As an alternative,a hybrid system with the spin–phonon–photon triple interactions mediated by a squeezed cantilever-type harmonic resonator is proposed.According to the general mechanical parametric amplification of this in-between phonon mode,the direct spin–phonon and photon–phonon couplings are both exponentially enhanced,which can even further improve the coherent manipulation of a single NV spin and MW photon with a higher efficiency.In view of this triple system with enhanced couplings and the additional sideband adjustable designs,this scheme may provide a more efficient phonon-mediated platform to bridge or manipulate the MW quantum and a single electron spin coherently.It is also hoped to evoke wider applications in the areas of quantum state transfer and preparation,ultrasensitive detection and quantum nondestructive measurement,etc.
基金supported by the Natural Science Foundation of Guangdong Province,China(Grant No.2017A030310085)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2018A050506034).
文摘The mechanical stability of tRNAs contributes to their biological activities.The mitochondrial tRNAArg from Romanomermis culicivorax is the shortest tRNA ever known.This tRNA lacks D-and T-arms,represents a stem-bulge-stem architecture but still folds into a stable tertiary structure.Although its structure had been reported,studies on its mechanical folding and unfolding kinetic characteristics are lacking.Here,we directly measured the single-molecule mechanical folding and unfolding kinetics of the armless mt tRNAArg by using optical tweezers in different solution conditions.We revealed a two-step reversible unfolding pathway:the first and large transition corresponds to the unfolding of acceptor stem and bulge below 11 pN,and the second and small transition corresponds to the unfolding of anticodon arm at 12 pN-14 pN.Moreover,the free energy landscapes of the unfolding pathways were reconstructed.We also demonstrated that amino acid-chelated Mg^(2+)(aaCM),which mimics the intracellular solution condition,stabilizes the bulge of mitochondrial tRNAArg possibly by reducing the topological constraints or stabilizing the possible local non-canonical base pairings within the bulge region.Our study revealed the solution-dependent mechanical stability of an armless mt tRNA,which may shed light on future mt tRNA studies.
文摘声学黑洞(acoustic black hole,ABH)效应是利用薄壁结构几何参数或者材料特性参数的梯度变化,使波在结构中的传播速度逐渐减小,理想情况下波速减小至零从而不发生反射的现象.实现声学黑洞效应的主要方法是将薄板结构的厚度按照一定规律裁剪,利用声学黑洞可以将结构中传播的波动能量聚集在特定的位置.声学黑洞对波的聚集具有宽频高效、实现方法简单灵活等特点,在薄壁结构的减振降噪、能量回收等应用中具有明显的优势.本文介绍声学黑洞效应的基本原理、相关力学问题的研究进展和有待进一步探究的问题,包括声学黑洞结构的建模与分析方法、实验研究方法及进展、声学黑洞结构中波的传播与操控,以及声学黑洞在工程应用中的相关问题.
文摘微机电系统(M EM S)以飞快的速度发展成为一个集微型机械、微传感器、微能源、微致动器、微控制器、微执行器、信号处理和智能控制于一体的新兴研究领域。微机电系统结构的复杂性促进了微装配技术的蓬勃发展,吸引了大批国内外研究人员对其进行广泛研究。本文首先分析了微器件装配技术对微机电系统的重要性及其产生的深远影响,然后介绍了近年来国内微装配技术的发展现状和参与微装配项目研发的研究单位的一些有应用价值的研究成果,最后阐述了微装配系统的发展趋势。
文摘A 6-DOF micro-manipulation robot based on a 3-PPTTRS mechanism is proposed in this paper.Its static stiffness is an important index to evaluate load capacity and positioning accuracy.However,it is insufficient to consider the static stiffness only when the robot is in its initial pose.The stiffness in different positions and poses in its work space must be analyzed also.Thus a method to analyze the relationship between static stiffness and poses in the whole work space is presented.A static stiffness model is proposed first,and the relationship between structural parameters and static stiffness in different poses is discussed.The static stiffness analysis provides foundation for structural parameter design.
