By forming alloys with Li ions, silicon (Si) can possess an energy capacity ten times that of graphite anodes, making it a promising candidate for the next generation anode materials for lithium-ion batteries. However...
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By forming alloys with Li ions, silicon (Si) can possess an energy capacity ten times that of graphite anodes, making it a promising candidate for the next generation anode materials for lithium-ion batteries. However, the large volumetric changes of Si during the lithiation/delithiation process result in unstable electrochemical cycling performance, and the deficiencies in electrical and ionic conductivity limit its rate performance, thereby constraining the large-scale application of Si-based anode. Due to its strong interaction with Si particles and its convenience in constructing doped carbon layers and carbon layers with special structures, polymers are regarded as low-cost (for example, the price of lignin is as low as 200–600 $/ton) and effective carbon sources to prepare core-shell structured Si@C composite materials and optimize the shortcomings of Si-based anodes. In this review, we first discuss surface modification methods for Si particles aimed at enhancing the adhesion to polymers and effectively improving the dispersibility of Si nanoparticles in polymers. Subsequently, the roles and methods for improving the electronic/ionic conductivity and structural stability of carbon layers, including doping and the construction of various special structures, are summarized and compared. These advancements position Si@C composites as viable candidates for next-generation high-energy batteries. Finally, the prospects for Si anodes coated with polymer-derived carbon layers are proposed.
As a common electronic packaging device, Kovar primarily serves to secure, seal, and protect semiconductor chips. The Ni–Au coating applied to its surface effectively resists external corrosion. However, residual str...
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Robot hand has a wide range of applications in the field of robot, which is used to connect the robot and the object temporarily, and can be released at the appropriate time. The robot hand grabs the object first and ...
Robot hand has a wide range of applications in the field of robot, which is used to connect the robot and the object temporarily, and can be released at the appropriate time. The robot hand grabs the object first and then releases it. In order to reduce the cost, the general robot hand is made into two parts with relative motion in order to realize the function of grasping and releasing. There are also many structures that mimic human hands and are designed to have more fingers and several joints, but that leads to higher system complexity. In order to solve the problems of adaptability and complexity, we design an adaptive robot hand with spiral blade expansion slide tube array. The device is used to grasp objects and achieve the effect of multi-directional grasping of objects. It can provide grasping force to the object in many directions, especially has good adaptability to the top and side of the object, and adapts to the grasping of objects of different shapes and sizes. All kinds of shapes placed in different directions can be grasped effectively. In the design of the robot hand, due to the array arrangement of the sliding tube, when the sliding tube buckles to the object from top to bottom, it can first be adaptive to the object in the horizontal direction, and then the expansion of the elastic thin film tube can be adaptive to the side of the object. Combined with the ascending motion of spiral rotation, the multi-directional grasping effect is achieved. Compared with the traditional robot hand, the robot hand has higher adaptability and simpler maneuverability. In this paper, the detailed design scheme of the machine hand is given, and the feasibility of the device is verified by force analysis. After improvement, the device has a certain demand on the production line that needs to be grasped.
In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase...
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In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low-concentration electrolyte, consisting of 0.5M NaPF 6 dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature. Such an electrolyte generates a thin, amorphous, and homogeneous cathode/electrolyte interphase at low temperature. The interphase is monolithic and rich in organic components, reducing the limitation of Na + migration through inorganic crystals, thereby facilitating the interfacial Na + dynamics at low temperature. Furthermore, it effectively blocks the unfavorable side reactions between active materials and electrolytes, improving the structural stability. Consequently, Na 0.7 Li 0.03 Mg 0.03 Ni 0.27 Mn 0.6 Ti 0.07 O 2 //Na and hard carbon//Na cells deliver a high capacity retention of 90.8 % after 900 cycles at 1C, a capacity over 310 mAh g −1 under −30 °C, respectively, showing long-term cycling stability and great rate capability at low temperature.
The exploration of the relationship between microstructure and properties is essential in materials research. However, traditional methods are often costly and time-consuming, and manual quantitative analysis is subje...
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Electrical double-layer supercapacitors are one type of electrochemical energy devices promising for next-generation energy storage, while they still suffer from great challenges of inferior energy density and poor to...
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The design of the most of the traditional multi-fingered hands is the imitation of human hand. It causes that a large number of simple operations can be realized only by using the finger joints or wrist, which brings ...
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ISBN:
(数字)9781728107707
ISBN:
(纸本)9781728107714
The design of the most of the traditional multi-fingered hands is the imitation of human hand. It causes that a large number of simple operations can be realized only by using the finger joints or wrist, which brings about complex control algorithm and the waste of time and energy. To solve this problem, this paper presents a novel design of robot finger with changeable surface for in-hand manipulation of co-fusion robots, called CS finger. Due to the special structure including pulley-belt mechanism and planetary gear mechanism, the surface of the CS finger can move in two directions and change the kind of the surface according to the environment, which makes many operations realized greatly easily and efficient like twisting the key to unlock and picking up soft cloth. Owing to its compact structure, low control requirements and high adaptability to the environment, the CS finger has important application prospects in the field of home services, micro-nano manufacturing and aeronautics and Astronautics, etc.
The ability to control magnetic vortex is critical for their potential applications in spintronic *** methods including magnetic field,spin-polarized current *** been used to flip the core and/or reverse circulation o...
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The ability to control magnetic vortex is critical for their potential applications in spintronic *** methods including magnetic field,spin-polarized current *** been used to flip the core and/or reverse circulation of ***,it is challenging for deterministic electric-field control of the single magnetic vortex textures with time-reversal broken symmetry and no planar magnetic *** it is reported that a deterministic reversal of single magnetic vortex circulation can be driven back and forth by a space-varying strain in multiferroic heterostructures,which is controlled by using a bi-axial pulsed electric ***-field simulation reveals the mechanism of the emerging magnetoelastic energy with the space variation and visualizes the reversal pathway of the *** deterministic electric-field control of the single magnetic vortex textures demonstrates a new approach to integrate the low-dimensional spin texture into the magnetoelectric thin film devices with low energy consumption.
This paper proposes a switchable parallel grasping, coupled and self-adaptive robot hand with idle-stroke transmission mechanism (SPCS-IS hand) which integrates the three basic grasping modes, namely parallel grasping...
This paper proposes a switchable parallel grasping, coupled and self-adaptive robot hand with idle-stroke transmission mechanism (SPCS-IS hand) which integrates the three basic grasping modes, namely parallel grasping mode, coupled grasping mode and self-adaptive grasping mode. The idle-stoke transmission mechanism (IS mechanism) is adopted into the robot hand mechanism design, so as to introduce two stages for the robot hand grasping motion. The SPCS-IS hand uses a switching device to realize the transformation between parallel grasping and coupled grasping for the first stage of grasping motion, then it will perform the self-adaptive grasping mode for the second grasping stage under the action of spring and limit device. The whole device contains only one motor and uses gear train to complete power transmission. Due to the integration of multiple grasping modes, the SPCS hand has stronger function and wider application range, especially its self-adaptability makes it can achieve envelopment for objects with different size and shape. Kinematic analysis and dynamic analysis are performed to research the adaptability and grasping ability of SPCS hand.
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