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Flexible three-dimensional (3D) force sensors have been extensively investigated in the field of robotics due to their ability to provide feedback information from multiple directions. However, the development of flexible 3D force sensors with high sensitivity and decoupling capabilities remains a significant challenge, hindering the ability of robots to perceive their external environment. In this letter, we present a novel flexible 3D force iontronic sensor (FTIS) that utilizes ionic materials with micro-pyramidal structures and a backpropagation (BP) neural network method based on deep learning. The FTIS exhibits outstanding sensitivity, with over 8000 $\text{N}^{-{1}}$ in the normal direction and over 4000 $\text{N}^{-{1}}$ in the shear direction, and has a rapid response time of 27-ms. Additionally, it demonstrated stable working durability, with over 8000 cycles without signal delay. To validate the utility of the sensor, we integrated it as a machine-sensing interface on a mechanical claw to measure changes in forces in the triaxial direction. Our design concept has the potential to advance the development of multidimensional force sensors in the future.

In electron beam lithography (EBL), the proximity effect seriously influences pattern resolution under high-precision conditions. Mainstream proximity effect correction (PEC) methods based on 2-D fast Fourier transform (2D-FFT) calculate a large number of unexposed points; thus, it may suffer from low efficiency especially when the exposure layout is unevenly distributed. This article proposes an efficient unequally spaced grid PEC method for EBL based on the fast multipole method (FMM). FMM in PEC just calculates the interaction between all the exposure points, and thus, it gets rid of the limitation of the equally spaced grid. Compared to the state-of-the-art PEC method based on 2D-FFT, the calculation speed of FMM will exceed the current fastest 2D-FFT convolution when the layout exposure density is below a certain proportion (approximately 80% under the 10-thread CPU parallel computing conditions). For the application of integrated circuit (IC) mask industry, the error of FMM is within the acceptable range of PEC. The PEC method in this article has been applied to a free software via software as a service (SaaS) mode, and a Windows-based EBL simulation and optimization software toolkit “HNU-EBL,” which is freely available at http://www.ebeam.com.cn.

Soft piezocapacitive sensor, owing to its simple assembly and low power consumption, draws intensive interests for physiological monitoring. However, crosstalk between proximity sensing units and limited mechanically stretching suppressed its practical application for conventional capacitive sensor array. Here we report a stretchable iontronic pressure sensor (SIPS) array with low proximate crosstalk for epidermal monitoring. Benefiting from electric double layer (EDL) capacitance effect between robust aramid nanofiber (ANF) /MXene (Ti3C2Tx) composite electrode and ionic film, the SIPS exhibits a high sensitivity up to 521.69 kPa−1, low limit of detection (0.22 Pa), broad linear sensing range (200 kPa) and rapid response time (17 ms) as well as long-term stable working durability for 10,000 cycles. The serpentine island bridge structure enables the SIPS array to stretch up to 40%, allowing pulse and grip monitoring of a bent wrist and finger, respectively, through processing circuits. This demonstrates the promising application prospects in vital physiological monitoring.

Significant efforts have been devoted to enhancing the sensitivity and working range of flexible pressure sensors to improve the precise measurement of subtle variations in pressure over a wide detection spectrum. However, achieving sensitivities exceeding 1000 kPa−1while maintaining a pressure working range over 100 kPa is still challenging because of the limited intrinsic properties of soft matrix materials. Here, we report a magnetic field-induced porous elastomer with micropillar arrays (MPAs) as sensing materials and a well-patterned nickel fabric as an electrode. The developed sensor exhibits an ultrahigh sensitivity of 10,268 kPa−1(0.6–170 kPa) with a minimum detection pressure of 0.25 Pa and a fast response time of 3 ms because of the unique structure of the MPAs and the textured morphology of the electrode. The porous elastomer provides an extended working range of up to 500 kPa with long-time durability. The sophisticated sensor system coupled with an integrated wireless recharging system comprising a flexible supercapacitor and inductive coils for transmission achieves excellent performance. Thus, a diverse range of practical applications requiring a low-to-high pressure range sensing can be developed. Our strategy, which combines a microstructured high-performance sensor device with a wireless recharging system, provides a basis for creating next-generation flexible electronics.

Underground gas storages (UGSs) rebuilt from gas reservoirs is the most popular UGS type in the world. It accounts for 75% of the total active gas of all gas storages. In order to design more scientific and reliable geological schemes for constructing the underground gas storages rebuilt from gas reservoirs and optimize the UGS operation parameters, we analyzed the UGS basic characteristics of multi-cycle high-rate injection and production. Then, the dynamic sealing capacity of traps and the water–gas high-speed interactive flow mechanism of UGSs rebuilt from gas reservoirs with complex geological conditions were investigated by both physical simulation and numerical simulation. Finally, the key technologies for evaluating the dynamic sealing capacity of caprocks and faults and the storage capacity parameters were developed. Some results were obtained. First, the alternating stress in the process of UGS injection and production weakens the original static capillary sealing capacity and mechanical integrity of caprocks to different extents, and the trap sealing capacity can be quantified and evaluated comprehensively by using dynamic breakthrough pressures, shear safety indexes and other indicators. Second, a UGS capacity design method based on effective gas-bearing pores was developed according to the local pore-based recovery mechanism revealed in the high-speed gas–water mutual flooding test. Field application in the multi-layer UGS of H shows that these technologies provide an effective guidance for the design of geologic schemes. After five cycles of injection and production, its ramp-up ratio reached 91.8% and the peak shaving capacity increased quickly to 36.3 × 108 m3from 2.7 × 108 m3in the early stage of production. Moreover, the operation indicators matched well with the design.

Micelles are self-assembled aggregates of amphiphilic surfactant molecules that are important in a variety of applications, including drug delivery, detergency, and catalysis. It is known that the micellization process is driven by the same physiochemical forces that drive protein folding, aggregation, and biological membrane self-assembly. Nevertheless, the molecular details of how micelle stability changes in water at low temperature are not fully clear. We develop and use a coarse-grained model to investigate how the interplay between nonionic surfactants and the surrounding water at the nanoscale affects the stability of micelles at high and low temperatures. Simulations of preformed C12E5micelles in explicit water at a range of temperatures reveal the existence of two distinct surfactant conformations within the micelle, a bent structure and an extended structure, the latter being more prevalent at low temperature. Favorable interactions of the surfactant with more ordered solvation water stabilizes the extended configuration, allowing nanoscale wetting of the dry, hydrophobic core of the micelle, leading to the micelle breaking. Taken together, our coarse-grained simulations unravel how energetic and structural changes of the surfactant and the surrounding water destabilize micelles at low temperature, which is a direct consequence of the weakened hydrophobicity. Our approach thus provides an effective mean for extracting the molecular-level changes during hydrophobicity-driven destabilization of molecular self-assembly, which is important in a wide range of fields, including biology, polymer science, and nanotechnology.

UGS (underground gas storage) construction in China has stepped into a new development stage after years of exploration. The eleven UGSs that have been put into production play an important role in domestic natural gas peak shaving safety and supply guarantee, with designed working gas volume of 180 × 108 m3, but there are still various difficulties in UGS construction in China. Firstly, the increasing speed of working gas volume is slower than that of peak shaving demand volume. Secondly, the UGS building engineering is difficult in technologies and high in investment costs. Thirdly, safe operation is under high pressure and it is hard to identify and control risks. Fourthly, there are fewer candidate UGS sites in China and UGS building conditions are complicated. And fifthly, it is difficult for those UGSs to realize economic benefits only based on their own operation under the existing natural gas price systems. To sum up, the currently available UGS operation modes and building technologies in China are not sufficient to cope with the challenges resulted from markets and complex geologic conditions. Facing all these challenges, it is necessary not only to explore market driven operation modes, but also to strengthen technology tackling and carry out core technological research and development, including geologic evaluation, gas reservoir engineering, drilling and completion engineering, UGS injection and gas recovery engineering, surface auxiliary technologies and UGS integrity evaluation, so that UGS building efficiency can be increased greatly.

The high demand for flexible force sensors with both strain and pressure sensing has attracted considerable attention for various application scenarios, such as electronic skins and smart prostheses. However, successful application of these sensors in real-world is challenging because the performance of the sensors can be severely degraded under applied off-axial deformations (e.g., bending and twisting) and it is also difficult to successfully decouple these signals due to electromechanical crosstalk. Here, we developed an integrated sensor patch (ISP) consisting of a strain sensor insensitive to pressure, bending and twisting, coupled with a pressure sensor insensitive to tension, bending and twisting. Benefiting from the serpentine structure and bionic design of strain sensor material, as well as the inherent rigidity properties of the piezoelectric ceramic, the resulting patch exhibits insensitivity to off-axis sensing with independent tensile strain and out-of-plane pressure sensing capabilities. The patch achieves a wide range of tensile strains (up to 160% with an apparent pressure coefficient of over 1.23) and a wide range of pressures (1Pa to 100 kPa). We demonstrate that the wearable ISP can interact human gestures with the robotic hand in real time through a fully soft integrated glove and further continuously record wrist activity to verify tensile strain sensing independent of pressure mode. In addition, the ISP successfully captures the subtle strain of less than 20% of eye blinks and the ultra-low pressure of less than 1.2 kPa of unobtrusive exhalation force with low off-axis interference. Moving forward, this strategy of endowing sensors with off-axis sensing insensitivity and decoupled strain and pressure sensing has great potential in human-machine interface (HMI), virtual reality (VR)/augmented reality (AR) user interfaces, and other soft electronics fields.

Highlights:

The iontronic pressure sensor achieved an ultrahigh sensitivity (Smin> 200 kPa−1, Smax> 45,000 kPa−1).

The iontronic pressure sensor exhibited a broad sensing range of over 1.4 MPa.

Pseudocapacitive iontronic pressure sensor using MXene was proposed. ABSTRACT: Flexible pressure sensors are unprecedentedly studied on monitoring human physical activities and robotics. Simultaneously, improving the response sensitivity and sensing range of flexible pressure sensors is a great challenge, which hinders the devices’ practical application. Targeting this obstacle, we developed a Ti3C2Tx-derived iontronic pressure sensor (TIPS) by taking the advantages of the high intercalation pseudocapacitance under high pressure and rationally designed structural configuration. TIPS achieved an ultrahigh sensitivity (Smin> 200 kPa−1, Smax> 45,000 kPa−1) in a broad sensing range of over 1.4 MPa and low limit of detection of 20 Pa as well as stable long-term working durability for 10,000 cycles. The practical application of TIPS in physical activity monitoring and flexible robot manifested its versatile potential. This study provides a demonstration for exploring pseudocapacitive materials for building flexible iontronic sensors with ultrahigh sensitivity and sensing range to advance the development of high-performance wearable electronics.

Highlights:

The laser-engraved method was introduced to fabricate the electrode for the sensor.

The sensor showed a wide linear working range, superior sensitivity, and fast response time and also exhibited excellent viability in a wet situation.

Wireless integrated network sensors successfully monitored the health states. Abstract: Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things (IoT) infrastructures. For flexible piezoresistive sensors, traditionally most efforts are focused on tailoring the sensing materials to enhance the contact resistance variation for improving the sensitivity and working range, and it, however, remains challenging to simultaneously achieve flexible sensor with a linear working range over a high-pressure region (>?100 kPa) and keep a reliable sensitivity. Herein, we devised a laser-engraved silver-coated fabric as “soft” sensor electrode material to markedly advance the flexible sensor’s linear working range to a level of 800 kPa with a high sensitivity of 6.4 kPa-1yet a fast response time of only 4 ms as well as long-time durability, which was rarely reported before. The integrated sensor successfully routed the wireless signal of pulse rate to the portable smartphone, further demonstrating its potential as a reliable electronic. Along with the rationally building the electrode instead of merely focusing on sensing materials capable of significantly improving the sensor’s performance, we expect that this design concept and sensor system could potentially pave the way for developing more advanced wearable electronics in the future.

A Novel conical conformal linear array antenna made up of 7 elements is proposed in this paper. Each element employing independent feeding consists of the overlapping top square, medium dielectric layer, array supported layer and back ground. The linear array antenna is wrapped around a conical surface to realize the integration. Through analyzing element working performance and linear array antenna on plane, the conformal array antenna wrapped around a conical surface just smaller curvature can be of analogy to reduce the experimental process. The presented conformal antenna operates at 4.86GHz over C-band. Multi-ports excitations have a vigorous characteristic in terms of a wide scanning angle and high gain than 10dBi. This method of the conformal array antenna analysis and the proposed design of antenna array integrating with supported layer can be employed a morph antenna and reduce the manufacturing cost for C-band.