压阻式柔性应变传感器研究进展

在信息时代,传感器已渗透到各个领域。压阻式柔性应变传感器因其优良的柔韧性、可拉伸/弯曲性以及在异形物体表面的“随形”贴合性,在智能穿戴、人机交互、结构服役过程监测等领域发挥了重要作用。压阻式柔性应变传感器一般有填充式、夹层式和吸附式三种结构,三种结构在制备复杂程度、重复性及传感性能等方面均有差异。研究者们多采用传统方法实现结构构筑,但传统方法普遍存在操作复杂、成本高、重复性差等问题,而采用新兴的3D打印技术可以高效、高精度、可重复地构筑传感结构,赋予了传感器更大的发展空间。在构筑压阻式柔性应变传感器时需采用柔性基体材料和导电填料,构筑得到的传感器主要有裂纹扩展、导电网络断开和隧穿效应三种传感机制,传感机制的形成与传感器的微观结构和材料有关。另外,压阻式柔性应变传感器的传感性能通常通过灵敏度、传感范围、耐久性等参数来表征,而如何兼具多项优异性能是目前的研究热点。同时,压阻式柔性应变传感器的配套器件和技术是限制其发展的主要因素,尤其是在供电和信号传输方面。本文归纳了压阻式柔性应变传感器在材料选择、结构构筑、机理探索、性能优化、应用开发等方面的研究进展,分析了压阻式柔性应变传感器目前所面临的...     

炭黑/聚丙烯-聚(苯乙烯-乙烯/丁烯-苯乙烯)复合材料的介电性能和压阻性能

为了制备柔性较好的聚合物基压阻材料,利用熔融共混法制备了炭黑/聚丙烯-聚(苯乙烯-乙烯/丁烯-苯乙烯)(CB/PP-SEBS)复合材料,并研究了CB含量对CB/PP-SEBS复合材料介电性能和压阻性能的影响。结果表明:随着CB含量的增加,CB/PP-SEBS复合材料的介电常数、介电损耗及电导率均提高;CB/PP-SEBS复合材料发生导电逾渗时,CB的含量为12.2wt%;在CB/PP-SEBS复合材料发生弹性形变时,由于外力破坏了CB的导电网络,复合材料的电阻随着应变的增大而增大;循环压阻测试结果显示,在弹性变形区CB/PP-SEBS复合材料的电阻随着应变呈现周期性变化。研究结果可为制备具有稳定电阻变化的聚合物基压阻材料提供借鉴。     

“小型固态压阻式压力传感器”通过技术鉴定

为满足航空发动机研制中对各种压力参数测量的需要，三○四所组织技术人员，在原固态压阻式压力传感器系列产品的基础上，进行了微型化技术研究。通过近三年的研制，目前，已研制成功性能稳定的直径为o25mm的小型固态压阻式压力传感器系列产品。并于1996年12月26日通过了由中国航空工业总公司科技局主持的技术鉴定。来包总公司、研究所、院校、部队的九名专家认为，该项目已完成了课题预定任务，并在小型化传感器的材料工艺、结构设计、实验研究等方面做了大量的具有特色的工作。该传感器的主要性能指标：不重复性可达02％F．S，非线性可达…     

用于电阻式柔性应变传感器的导电聚合物复合材料研究进展

作为物联网的触角,传感器迎来了新的发展机遇。而随着可穿戴行业的发展,电阻式柔性应变传感器在人体穿戴实时监测、机器人仿生皮肤、医学健康跟踪、运动肢体捕捉以及生产振动检测等领域展现出广阔的应用前景。聚合物导电复合材料是电阻式柔性应变传感器最常用的应变传感核心材料,具有柔性好、应变检测范围大以及成本低的优势。但现有的基于聚合物导电复合材料的传感器普遍存在迟滞明显、线性度低、导电网络稳定性差的缺点,此外对于某些复合材料在应变过程中的导电机理阐释也存在缺陷。因此,近年来诸多学者从聚合物导电复合材料导电机理、不同导电填料的特性、聚合物本身特性以及不同的制备工艺等方面开展了大量的研究工作。在解释聚合物导电复合材料的导电机理方面,目前多采用渗流理论解释其导电过程。目前聚合物导电复合材料所用的导电填料主要分为碳系导电填料和金属系导电填料两大类,由于碳系导电填料的导电稳定性好、价格低,是目前使用的主流。而目前使用的聚合物基体主要分为硅橡胶、天然橡胶以及聚氨酯三大类,硅橡胶主要用于小应变、高灵敏度传感器,天然橡胶主要用于大应变传感器。而聚合物导电复合材料的制备工艺主要分为填充式、夹心式、吸附式三种,填充式的传感器应变范围较大,而夹心式和吸附式传感器应变范围相对较小。本文对聚合物导电复合材料的导电机理、导电填料、聚合物基体以及不同制备工艺进行了归纳和分析,并展望了柔性应变传感用聚合物导电复合材料今后可能的研究热点和发展趋势。     

橡胶/炭黑导电复合材料的压阻效应研究进展

综述了炭黑填充的压敏导电橡胶复合材料的压阻机理、压阻特性和压阻数学模型等方面的研究工作进展。讨论了加工工艺条件、填料性质、分散性等因素对压敏导电橡胶复合材料的压阻性能及压阻稳定性的影响。     

生物质衍生碳在电阻式应变/压力传感器中的最新应用进展与关键挑战（英文）

近年来电阻式应变/压力传感器在运动行为监测、人类健康诊断和人机交互等领域展现了不可替代的作用,因而刺激了人们对其需求的急剧增长.材料和结构设计对电阻式应变/压力传感器的性能有着不可忽视的影响,而生物质碳(BDCs)具有丰富的来源、多样的结构和令人满意的导电性等优良特性,被认为是制造电阻式应变/压力传感器的优异候选材料之一.本综述介绍了BDCs材料在电阻式应变/压力传感器领域的最新进展及其目前面临的主要挑战.首先,系统地概述和讨论了已报道的电阻式应变/压力传感器的分类方法、评价标准和传感机制.其次,总结了具有不同宏观结构(包括一维、二维和三维结构)的BDCs材料的制备及其在电阻式应变/压力传感器领域的最新应用进展.详细分析了具有不同宏观结构的BDCs材料在电阻应变/压力传感器领域的各自应用优势,并讨论了不同宏观结构与器件综合传感性能之间的关系.最后,提出了基于BDCs材料的电阻式应变/压力传感器的未来前景和主要挑战,及其未来发展的研究方向.     

碳基纳米复合材料应变传感器的研究现状

传统的金属及半导体应变计的灵敏度低、韧性及延伸性差,限制了其在高应变领域的应用,因此提高应变传感器的敏感系数及应变性能成为一个重要的发展方向,柔韧的碳基纳米复合材料应变传感器是一种有效的解决方法。本文综述介绍了碳基纳米复合材料应变传感器的研究现状,包括:碳基纳米材料在聚合物基体中的含量、取向、分散性对应变传感器的性能的影响,不同基体复合材料传感器的制备方法以及应变传感性能,比较了它们的优缺点,为碳基纳米复合材料应变传感器的研制与开发提供参考。     

金属流密封方式介绍

在压力传感器应用领域,压阻式传感器的发展是当今最为迅速的。而面对日益巨大的市场价值,传感器的制作工艺变得尤其重要。压力传感器的结构设计和制作工艺对传感头的封装、密封尤为重要。该文介绍了一种名叫"金属流"的新型密封承压方式,具有许多优势应用于压阻式压力传感器,也适合推广到其他应用领域。     

汽车碰撞试验用多轴压阻加速度传感器及校准方法

通过对汽车碰撞试验用多轴加速度传感器的特性介绍,推荐了在汽车碰撞试验领域中多轴压阻式加速度传感器的选用方法。并针对汽车碰撞试验用多轴压阻式加速度传感器的计量性能结合相关标准及设备对主要校准 参数、方法做了探讨,建立了一套基于比较法为原理的校准方法。从而进一步保障汽车碰撞试验数据的准确度,提升碰撞试验的可信度。     

纳米二氧化钌对硅橡胶基力敏复合材料压阻性能的影响

选用乙烯基硅橡胶(SIR)为力敏复合材料基材,纳米二氧化钌(nano-RuO2)为导电功能粒子制备纳米RuO2/SIR力敏复合材料.测试了纳米RuO2/SIR复合材料的压阻性能,分析了纳米RuO2在纳米RuO2/SIR复合材料中的逾渗阈值区间以及纳米RuO2用量对纳米RuO2/SIR复合材料的压阻性能及其压阻性能稳定性的影响,在此基础上制备出具有较好压力敏感性及良好的压阻重复性能的纳米RuO2/SIR复合材料.研究结果表明,一定用量的纳米RuO2在改变硅橡胶电性能的同时,还具有显著的补强作用.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...