Silk fabric electronic skins (E-skins) enable a more natural and delicate interactive experience for smart devices. However, achieving precise structural design, interfacial stability, and skin-like functionality often requires intricate manufacturing processes and sophisticated equipment. Herein, a mass-produced, highly flexible texture-programmed silk fabric E-skin is developed by employing an advanced jacquard process coupled with a polyphenol coordination-mediated deposition strategy. The E-skin features broad strain-sensing capabilities, enabling it to monitor both light and heavy rhythmic vibration signals, facilitate information interaction via Morse code, and exhibit a fast response time of 60 ms. In addition, this E-skin possesses multimodal information sensing capabilities and can accurately identify objects with varying surface roughness (10-90 μm) and hardness (2.0 HA-42.7 HD). Notably, by utilizing machine learning algorithms, it can specifically differentiate between four fabrics that have the same raw materials and weaving density but differ in micron-scale circular structures (accuracy > 95%). Overall, the texture-programmed silk E-skin offers advanced multimodal sensing for health monitoring, motion tracking, and tactile sensing.

The continuous improvement of microelectronic device performance is increasingly constrained by rapidly rising heat flux densities, making efficient thermal management a major challenge. The authors discussed a novel dual-layer microchannel heat sink with central impinging jets and diamond-shaped fins to enhance heat transfer performance. All possible configurations involving two representative flow schemes were numerically investigated. Samples were manufactured using SLM technology. The designed and implemented experiment agree well with the numerical simulation. The results indicate the flow configuration combining both lateral and jet inlets provide superior global temperature uniformity with lower energy consumption. The fins arranged at the fluid intersection region generate strong flow disturbances, which further promote heat transfer. At an inlet velocity of 0.6m/s, the working condition IJFMHS-B demonstrated the best overall performance, which includes fins, and the coolant is injected simultaneously at the side and top inlets. Compared with the baseline design, the average substrate temperature decreased by 5.1K, the temperature difference was reduced by 11.7K, and the pressure drop decreased by 26.3%. The overall performance evaluated using the PEC factor of IJFMHS-B exhibited an enhancement of up to 34.9%. Moreover, the effect of jet flow ratio was explored. Considering the heat dissipation, power consumption, and temperature uniformity, the optimal range was identified between 45% and 50%. Finally, a Latin hypercube sampling (LHS) strategy was employed to construct precise surrogate models of the objective functions, and the main fin dimensions were optimized using the NSGA-II algorithm. The predicted optimal solutions showed an error of less than 3% under the assigned weighting conditions.

To address the challenges of high energy consumption and poor sustainability in reconfigurable intelligent surfaces (RIS)-assisted Internet of things (IoT) systems relying on external power supply, a self-sustainable RIS-assisted simultaneous wireless information and power transfer (SWIPT) IoT system was investigated and designed. First, a dynamic hybrid-mode RIS architecture was proposed, in which each RIS element can flexibly switch between energy harvesting and signal reflection modes to achieve self-sustainability. A joint multi-resource optimization problem was then formulated with the objective of maximizing the system’s energy efficiency, subject to multiple constraints, including the transmit power at the base station, the minimum energy harvesting requirements and quality-of-service of IoT devices, and the energy causality of RIS. The transmit beamforming, power splitting factors of IoT devices, and the operating modes and phase shifts of RIS elements were jointly optimized. Finally, to tackle the highly coupled non-convex mixed-integer optimization, an efficient iterative algorithm was developed by integrating fractional programming, penalty function methods, successive convex approximation, and semidefinite relaxation, which can achieve high-quality suboptimal solutions. Simulation results show that the proposed scheme consistently yields significant improvements in energy efficiency over baselines under various system settings, with an average gain of 5.7% in typical scenarios.

Silk fabric-based wearable electronics stand among the most effective materials for the electronic skin function, due to their flexibility, robust mechanical features, and bio-compatibility. However, the development of fabric sensors is restricted by limited resilience and the weak binding force of conductive materials to fabrics. Herein, a general strategy is developed for designing SF wearable devices with high elasticity and conductivity, combining the macroscopic design of three-dimensional SF structure, microscopic plasma-activated β-FeOOH scaffolds and in situ polymerized polypyrrole. Significantly, the fabric exhibits a maximum tensile strain of up to 30

Limitations of current electronic textiles (e-textiles), including poor washability, instability, and inferior sensing capability, are concerns hindering their broad and practical applications in personal health care management, virtual games, sports, and more. Here, we report an RGO/PANI e-textile via alternative coatings of in situ reduced graphene oxides (RGO) and in situ polymerized polyaniline (PANI), establishing a laminated structure on a knitted textile substrate. As a result of an in situ lamination strategy, our e-textile exhibits excellent breathability (1428 mm s−1, greater than that of bare cotton fabric) and outstanding sensitivity (gage factor of 39.7) over a wide strain range ( 0.0625–200

Low electromagnetic interference (EMI) is essential for isolated DC-DC converters that are used in the harsh industrial environments. To pass the CISPR 32 Class-B EMI standard, a 4-layer PCB with a stitching capacitor implemented by the internal layers is commonly required [1], which greatly increases the cost of the system and the effort of PCB layout. Therefore, low-cost circuit techniques that can reduce EMI at the source are highly desirable. As shown in Fig. 14.7.1, input-to-output dipole radiation caused by the common-mode (CM) current I CM across the parasitic capacitance C P of the isolation barrier is the predominant mechanism of EMI, and the fluctuation of the CM voltages of the transformer at the primary and the secondary side, V CM_PRI and V CM_SEC , should be suppressed to reduce I CM . V CM _ SEC can be kept quiet by adopting a symmetrical full-bridge rectifier in the receiver (RX) side, and thus the amplitude of I CM mainly depends on the fluctuations of V CM _ PRI which are determined by the topology of the transmitter (TX). Unfortunately, when using the LC-tank oscillator adopted in [2] and [3], or the leakage-inductance-resonant flyback (LiRF) topology proposed in [4], V CM _ PRI suffers from large and quick fluctuations. Frequency hopping technique can be employed to reduce I CM [2], but it will greatly increase the output voltage ripple and the circuit complexity. In [5], an LLCC topology with a multistage pre-driver is proposed to form a more symmetrical structure to reduce I CM . However, a costly magnetic-core micro-transformer and two extra external capacitors are needed.

Herein, a MnFe 2 O 4 /RGO knitted fabric derived from manganese waste was constructed by a simple in-situ assembled coating method, involving the incorporation of Graphene Oxide (GO) and manganese ferrite nanoparticles on polyester fabric, followed reducing by hydrazine hydrate. The reuse of manganese waste from the preparation of GO can reduce chemical waste emissions and endow the absorption performance. The coated particles possess certain magnetism can be attracted and securely collected in seconds, which is convenient for recycling. This fabric gives well microwave absorption with the maximum reflection loss (RL) of −58.6 dB at 9.1 GHz by a thickness of 1.9 mm. In addition, this fabric presents high stable strain sensing under 1000 stretching and bending cycles. Meanwhile, the resistance-deformation-velocity relationship is provided based on the structure, for the analysis of electromechanical behaviors. Moreover, the fabric has the capability for temperature sensing (TCR=−0.738%/°C), and fire alarm. As such, this fabric can be promising alternatives for a wide application on motion and temperature sensing, microwave blocking. Keywords Manganese waste , MnFe , O , /RGO fabric , microwave block , high stable , strain sensing

Disposable face towel derived amorphous carbon prepared by annealing for broad and exacting applications in electromagnetic shielding, electrical heating, etc. This mat with 3D conductive network formed by nonwoven viscose fiber structure gives an outstanding electromagnetic shielding performance of 30 dB and 8161 dB/(g/cm2) at a thickness of 0.168 mm in the frequency range of 0.3–3.0 GHz. In addition, the as prepared mat presents excellent temperature & strain sensing with exceptional sensitivity (BS = 5.5%), and favorable flexibility (1000 bending cycles without fracture). Moreover, the mat provides well Joule heating performance, and the heating temperature can reach over 60°C in 32 seconds under 0.25 A current. More interestingly, the mat shows excellent fire alarm with a fast response (84 ms) and high operating temperature (>500°C). This method provides a simple and low-cost new method for radiation protection, temperature detection, fire alarm and other fields.

Herein, a MnFe 2 O 4 /RGO knitted fabric derived from manganese waste was constructed by a simple in-situ assembled coating method, involving the incorporation of Graphene Oxide (GO) and manganese ferrite nanoparticles on polyester fabric, followed reducing by hydrazine hydrate. The reuse of manganese waste from the preparation of GO can reduce chemical waste emissions and endow the absorption performance. The coated particles possess certain magnetism can be attracted and securely collected in seconds, which is convenient for recycling. This fabric gives well microwave absorption with the maximum reflection loss (RL) of −58.6 dB at 9.1 GHz by a thickness of 1.9 mm. In addition, this fabric presents high stable strain sensing under 1000 stretching and bending cycles. Meanwhile, the resistance-deformation-velocity relationship is provided based on the structure, for the analysis of electromechanical behaviors. Moreover, the fabric has the capability for temperature sensing (TCR=−0.738%/°C), and fire alarm. As such, this fabric can be promising alternatives for a wide application on motion and temperature sensing, microwave blocking.

对一种变转速的便携式光伏直驱冰箱进行实验研究.实验中分别研究内置风扇、环温、转速控制策略对冰箱性能的影响.增设内置风扇对负载的降温速率影响明显,水温降至5℃的运行时间减少39.3％;环境温度从20℃升至30℃,最终制冰量下降23.9％,净制冷量下降10.5％;改变转速控制策略,变转速相比定转速最终全天平均光伏利用效率提高48.1％,制冰量提升99.6％,净制冷量增幅为22.8％.实验结果表明,内置风扇能显著提升冰箱内部的降温速率并减少运行时间;环温升高对便携式冰箱制冷效果影响明显,制冷量随环温升高而下降;光伏直驱冰箱采用变转速控制策略后,能大幅提高光伏利用效率,增加制冷量,提升系统的性能表现.

在同种工况下,对外置式PV-Trombe墙与内置式PV-Trombe墙进行自然对流实验,对比研究2种系统装置的热性能与电效率.研究结果表明,相比于外置式PV-Trombe墙,内置式PV-Trombe墙的空气集热效果更加明显,且内置式PV-Trombe墙与外置式PV-Trombe墙的上下风口最高温差可分别达到14.9和13.5℃.带有内置式PV-Trombe墙的房间的平均温度比带有外置式PV-Trombe墙房间的平均温度高1.5℃.在光电转化方面,外置式PV-Trombe墙的太阳电池模块效率高于内置式PV-Trombe墙的太阳电池模块效率.内置式PV-Trombe墙的太阳电池的工作温度较高,且受边框阴影的影响严重,光电转化效率较低.

This paper proposes and builds a novel type of high concentration photovoltaic/thermal (HPV/T) system,combines the Fresnel type point-focus photovoltaic system with PV/T system effectively,and carries on the experimental study.Through outdoor test and analysis of data,the result showed that direct current rises with the rise of direct irradiation.At first,when the tank temperature is low,there is little fluctuation on the output direct voltage.When the temperature in water tank is too high,the output of direct voltage rises slowly.The peak power can reach 12.10 kWh.From 09:40 to17:00,power generating capacity is 77 kWh in this system.The highest instantaneous electrical efficiency is as high as 28.9％,and the average electrical efficiency is 27.36％.The highest instantaneous thermal efficiency is more than 33.54％,and the average thermal efficiency is 30.02％.The overall efficiency of the system is more than 60.00％.

提出一种多功能太阳能PV/T集热器(tri-functional PV/T solar collector),将加热空气和加热水2种功能结合,从而实现PV/T集热器全年的高效利用,满足不同的能量需求.该文搭建2套实验平台对于2种工作模式的光电光热性能进行对比实验研究,并对不同空气流量和进口温度下的PV/T集热器光电光热性能进行分析.结果表明,此多功能PV/T集热器在2种工作模式下均可实现太阳能高效利用.

提出一种光伏直驱式热水系统,并建立系统的流量模型,研究和比较3种不同的连接方式(直接连接,光伏分组连接,通过最佳功率输出控制器(MPPT)连接)下系统的流量特性.搭建实验系统,实验验证模型的准确性.结果显示:在相同的启动辐照下,随着辐照度的增大,使用直接连接方式时,系统流量先增大后基本恒定;使用光伏分组连接的方式时,系统流量先基本恒定后逐渐变大;使用有MPPT的连接时,系统流量基本呈线性升高.此外,直接连接方式所需的太阳电池最多,采用有MPPT的连接方式所需的太阳电池最少且其太阳电池的输出效率也最高.但光伏分组连接方式最具经济性.考虑到经济性和稳定性,光伏分组连接方式应为此类热水系统的首选连接方式.该研究可对光伏直驱式热水系统中光伏与泵的连接方式的设计提供参考和依据.

Most solar water heating systems (SWHS) are forced circulation systems using AC pumps. Controlled by an ON/OFF differential temperature sensing controller, the heat transfer fluid in a SWHS flows at a constant rate, and the controller consumes electricity. The controller and the sensors lead to system malfunctions, and AC pumps cycle between ON and OFF frequently under low solar irradiance. Hence, PV direct-coupled DC pumps are promising in SWHS, since they are simple and reliable. In this study, an optimization study of a PV direct-coupled SWHS (PV-SWHS) which uses a PV direct-coupled DC pump to circulate the heat transfer fluid is presented. A system model is built and validated with experiments. Two different types of PV module designs are investigated. The performance of the PV-SWHS under different real weather conditions is studied and compared with the performance of the conventional SWHS. And an optimum design method of PV-SWHS is proposed. The results show that: (i) the startup solar irradiance of the pump is the major factor which affects the thermal efficiency of PV-SWHS; (ii) a proper PV module design can reduce the requirement of PV cells by more than 25%; (iii) the PV-SWHS can work well without circulation controller; (iv) the optimized PV-SWHS has nearly the same thermal efficiency and better long-term system reliability than the conventional SWHS. Therefore, the PV-SWHS is very promising.

介绍一个采用多种太阳能技术与建筑一体化的设计方案,包括太阳能光伏发电、热水、采暖、制冷等系统.针对各系统进行实验研究,根据所获得的数据,分析太阳能技术与建筑一体化的性能表现.

Characteristics of a high concentration photovoltaic/thermal (HCPV/T) module equipped with point-focus Fresnel lens have been investigated in this paper. Both electrical and thermal models of the module are developed by numerical methods. The electrical model is based on the Shockley diode equation, and the thermal model is grounded on a two-dimensional steady-state heat transfer model. Influences of environmental parameters and coolant water are considered in the models. The inputs of the models consist of irradiance, ambient temperature, wind speed, water temperature and mass flow rate. The outputs mainly include electrical efficiency and thermal efficiency. The simulated results are compared with experimental results and a great agreement is obtained. By the virtue of the validated models, influences of different parameters on module performance are analyzed in detail. The results show that an electrical efficiency of 28% and a thermal efficiency of 60% can be obtained by the HCPV/T module. The electrical efficiency is mainly influenced by solar irradiation rather than cell temperature. The thermal efficiency increases with the increment of irradiance, ambient temperature and water mass flow rate. On the contrary, increasing water temperature and wind speed will lower the thermal efficiency. Also, the HCPV/T module can produce hot water as high as 70 degrees C without decreasing the electrical efficiency seriously. (C) 2016 Elsevier Ltd. All rights reserved.

A high concentrator photovoltaic/thermal (HCPV/T) system based on point-focus Fresnel lens has been set up in this work. The concentrator has a geometric concentration ratio of 1090x and uniform irradiation distribution can be obtained on solar cells. The system produces both electricity and heat. Performance of the system has been investigated based on the outdoor measurement in a clear day. The HCPV/T system presents an instantaneous electrical efficiency of 28% and a highest instantaneous thermal efficiency of 54%, which means the overall efficiency of the system can be more than 80%. A mathematical model for calculating cell temperature is proposed to solve difficult measurement of cell temperature in a system. Moreover, characteristics of electrical performance under various direct irradiation intensity and cell temperature are also studied. The results show that direct irradiation affects the electrical performance of the system dominantly. Fitting results of electrical performance offer simple and reliable methods to analyze the system performance. (C) 2015 Elsevier Ltd. All rights reserved.

In this paper, the electrical and thermal performances of both Fresnel concentrator photovoltaic/thermal (FCPV/T) modules with thermal collector and FCPV modules with passive cooling heat-sinks are investigated in experimental method. Both types of modules are equipped with triple-junction solar cells. Their geometric concentrating ratio is as high as 1090x. Comparative analysis has been conducted based on experimental data. The experimental results have been analyzed from the viewpoint of thermodynamics. From the first law point of view, it is found that the overall efficiency of the FCPV/T modules can exceed 80% but it drops significantly as the coolant water is heated up. Meanwhile, the electrical efficiency of the two types of modules can reach up to 28.9%. While from the second law point of view, a highest exergetic efficiency of 33.9% and 28.9% can be produced by the FCPV/T modules and the FCPV modules, respectively. Water temperature is found to play an insignificant role on the exergetic efficiency and irradiation influences dominantly. Besides, the electrical outputs of the two types of modules are almost equal at the same time even if notable operating temperature difference between their cells exists. Thermal profile of the CPV/T receiver has been simulated on the basis of a 3D heat transfer model developed in the thermal analysis software Comsol. The influence of beam irradiance and cell temperature on electrical efficiency is further studied. The results indicate that electrical performance of these modules is affected mainly by beam irradiance, and it is influenced little by cell operating temperature, which greatly differs from flat-plate PV/T modules.

主、被动结合的太阳能双效集热器空气采暖系统,可同时解决南向房间和北向房间的供暖问题.借助TRNSYS仿真平台,编写双效集热器的嵌入模块,对应用在太阳能示范建筑上的主、被动式双效集热器空气采暖进行模拟研究.模拟结果显示在合肥地区,木质结构的示范房只需白天供暖情况下,整个采暖期的太阳能保证率为38％,而同样条件下在拉萨和上海地区,太阳能保证率分别达到77％和58％;若示范建筑采用有蓄热能力的混凝土砖墙结构,在拉萨地区全天供暖条件下太阳能保证率达到64％;晴朗天气,南向房间和北向房间白天均可达到20℃舒适性温度.同时讨论集热器倾角、出口温度、集热面积等对主动式空气采暖太阳能保证率的影响.