Energy harvesting and temperature sensing thermoelectric devices based on the carbon template method

A series of self-supporting carbon nanomaterial films with different morphologies were employed as conductive templates for n-junction after polyethyleneimine (PEI) doping by taking advantages of the entanglement between carbon nanotubes. With the assistance of dimethyl sulfoxide (DMSO)-treated poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) films as p-junction, flexible and light-weight thermoelectric generators (TEGs) were assembled. The effect of the morphology of the carbon nanomaterial, including multi-walled carbon nanotube (MWCNT), whisker carbon nanotube (WSCNT), and graphene on the electrical conductivity, mechanical properties and morphology of n-junction was investigated, on basis of which thermoelectric properties of TEG were evaluated. The properties of the three carbon-based self-supporting films show significant differences. The MWCNT/PEI film exhibits a tensile strength of up to 36.23 ± 0.57 MPa due to the high entanglement network density of MWCNT. The entanglement of WSCNT/MWCNT/PEI provides an ideal conductive template for PEI to prepare n-junction material. TEGs with PEDOT:PSS-DMSO and WSCNT/MWCNT/PEI as p- and n-junctions show high power generation performance and cyclability. The output power density is up to 4.6 nW/cm² at ΔT = 42.0 K, matched to a suitable load. With its fast response and slow recovery, this TEG is expected to be used for human health monitoring and energy storage.     

Magnetically and Electrically Responsive Soft Actuator Derived from Ferromagnetic Bimetallic Organic Framework

The advancement in smart devices and soft robotics necessitates the use of multiresponsive soft actuators with high actuation stroke and stable reversibility for their use in real-world applications. Here, this work reports a magnetically and electrically dual responsive soft actuator based on neodymium and iron bimetallic organic frameworks (NdFeMOFs@700). The ferromagnetic NdFeMOFs@700 exhibits a porous carbon structure with excellent magnetization saturation (166.96 emu g⁻¹) which allows its application to a dual functional material in both magnetoactive and electro-ionic actuations. The electro-ionic soft actuator, which is fabricated using NdFeMOFs@700 and PEDOT-PSS, demonstrates 4.5 times higher ionic charge storage capacity (68.21 mF cm⁻²) and has excellent cycle stability compared with the PEDOT-PSS based actuator. Under a low sinusoidal input voltage of 1 V, the dual-responsive actuator displays bending displacement of 15.46 mm and also generates deflection of 10 mm at 50 mT. Present results show that the ferromagnetic bimetallic organic frameworks can open a new way to make dual responsive soft actuators due to the hierarchically porous structures with its high redox activity, superior magnetic properties, and larger electrochemical capacitance. With the NdFeMOFs@700 based soft actuators, walking movement of a starfish robot is demonstrated by applying both the magnetic and electric fields.     

Interplay Between Doping,Morphology, and Lattice Thermal Conductivity in PEDOT:PSS

Organic materials for thermoelectric (TE) applications have attracted a fair amount of attention in recent years due to remarkable advances achieved in terms of their figure of merit, ZT: a value of 0.42 has been reported by for poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films treated with dimethyl sulfoxide, while 0.25 has been obtained for PEDOT:Tosylate. In this study various PEDOT morphologies are investigated, considering both neutral and doped (bipolaronic) samples, by means of classical molecular dynamics, by taking advantage of a recently developed all-atom force field. In the case of bare PEDOT, it is found that changing the distribution of chain lengths affects the thermal conductivity of neutral and doped samples in a different way: longer chain lengths result in higher conductivities in the neutral scenario, whereas an intermediate chain length gives the highest value in the bipolaronic case. The role of PSS in the bipolaronic state, as compared to the simpler case where the counterion is Cl⁻, is discussed.     

Ag mesh network framework based nano composite for transparent conductive functional electrodes for capacitive touch sensor and thin film heater

We report on the development of a highly conductive, transparent and flexible Ag mesh-like network covered by an ITO/PEDOT:PSS nanocomposite for flexible conductive electronics. The electrode was deposited completely via solution-based deposition. A lower R_s value, from 7.21 Ω/□ to 5.05 Ω/□, was achieved by annealing the substrate via low-temperature plasma annealing. The low-temperature annealing was used to achieve crystallinity of the materials without deformation and degradation of PEDOT:PSS and the PET substrate. The low-cost deposition-based Ag NW-ITO/PEDOT:PSS electrode substantially decreased sheet resistance and provides the transmittance of 85.17%. The chemical stability and mechanical stability of the product were examined, and morphological studies were performed; in all of these, the substrate exhibited excellent behavior. Finally, a transparent flexible electrical heater and capacitive touch screen panel were fabricated using the Ag NW-ITO/PEDOT:PSS electrode to demonstrate the performance of the electrode and its potential applications.     

霍尼韦尔4000系列扫描架故障案例

霍尼韦尔的4000型扫描架在很多纸厂都有使用,长时间运行,受环境、备件寿命、维护保养不到位等因素的影响,其稳定性变差,会出现许多故障影响到正常使用。文中介绍了一例给扫描头供电的±15 v开关电源运行不稳定引起的定量和水分频繁且大幅波动的故障案例。通过对此次故障维修经过和总结的描述,分别进行了background测试、reference测试结果对比方法,放射源衰减后定量放大板放大倍数的调整方法,以及类似故障的维修思路和解决方法。     

Flexible pressure sensor with high sensitivity and fast response for electronic skin using near-field electrohydrodynamic direct writing

Electronic skin imitates the function of human skin. The flexible pressure sensor is an important sensor of electronic skin. Although the flexible pressure sensor has made some progress, electronic skin is still a challenging subject with good pressure resolution, high sensitivity, and fast response ability in biomedical, human motion detection, personal health monitoring, and other fields. The PEDOT:PSS/GR/SWCNTs multicomponent solution was directly written on the flexible PDMS substrate by the near-field electrohydrodynamic direct-writing method, a serpentine shaped pressure sensitive unit was prepared, which was encapsulated with the PDMS thin film, and the flexible pressure sensor was fabricated. The sensitivity of the flexible pressure sensor is about 0.39 kPa⁻¹ at 0–0.5 kPa and 1.04 kPa⁻¹ at 0.5–2.4 kPa, and the response/recovery speed is 75 ms/150 ms, respectively. The fabricated flexible pressure sensor can detect a small pressure of about 6.4 Pa. The experimental results show that the fabricated flexible pressure sensor has high sensitivity, fast response capability, and low detection limit. The flexible pressure sensor for electronic skin demonstrates good performance in the application of finger joint movement and word pronunciation recognition, which indicates that it has great potential application in human motion detection and personal health monitoring.     

电力系统稳定器试验与参数测试

三河发电厂在2004年度2号机组大修中完成了2号发电机组电力系统稳定器(PSS)的在线无补偿励磁系统频率响应特性测试;在线励磁系统有补偿相频特性仿真;PSS增益调整;在线电压阶跃响应试验校验PSS阻尼效果等试验,取得了良好的试验效果,现2号发电机组PSS系统投入正常运行。     

ITO-free flexible organic solar cells with printed current collecting grids

The presence of a transparent conductive electrode such as indium tin oxide (ITO) limits the reliability and cost price of organic photovoltaic devices as it is brittle and expensive. Moreover, the relative high sheet resistance of an ITO electrode on flexible substrates limits the maximum width of a single cell. We have developed an alternative ITO-free transparent anode, based on solution processed high conductive PEDOT:PSS in combination with a printed current collecting grid. The screen printed silver grid demonstrates a typical sheet resistance of 1 Ω/□ with 6.4-8% surface coverage. The efficiency of a flexible device with an active area of 4 cm² with such a grid is much higher than a similar device based on ITO. Furthermore, as this composite anode is solution-processed, it is a step forward towards low-cost large area processing.