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High winds are a type of catastrophic weather characterized by wind speeds over 10.8 m·s−1, occurring in all seasons, and have become more frequent, impacting crop growth, agricultural production and quality of life. It is crucial to understand the spatial and temporal distribution patterns of high winds, as well as their speed and other characteristics, for logical planning of agricultural production and the creation of disaster resilience measures. This study applied the climate tendency, accumulative anomalies, theory of run, Mann–Kendall trend and Theil–Sen median to analyse the spatial and temporal distribution characteristics of the average wind speed and high wind days in Jilin Province, the probability of occurrence of high winds of various magnitudes in different eras, and the gale concentration degree (GCD) throughout Jilin Province for a total of 40 years from 1982 to 2021. The average wind speed and number of high wind days in Jilin Province have decreased over the past 40 years, and this trend has slowed over time. The average GCD in Jilin Province has shown an increasing trend over the last 40 years, with the average GCD being highest in Liouhe and lowest in Linjiang. In general, level six high winds were the main wind hazard level in Jilin Province, with the highest frequency occurring in different seasons and decades. In addition, the occurrence of high wind days is affected by global climate change and different underlying surfaces, which leads to maize and yield reduction. Research on the spatiotemporal distribution of high winds can provide important suggestions for the prevention and management of high wind disasters. [ABSTRACT FROM AUTHOR]

Maize is susceptible to drought and low temperatures. In recent years, drought, low temperatures, and their composite events have often occurred during the growth period of maize, causing a huge impact. In this study, maize in the Songliao Plain was used as the research object. Based on the crop water surplus deficit index (CWSDI) and heat index (F(T)), combined with the Theil–Sen median and Mann–Kendall tests (Sen–MK) and empirical orthogonal function (EOF), the temporal trends and spatial patterns of drought and low temperatures in different growth periods of maize were obtained. Copula modelling was used to analyse the joint probability distribution and return period of drought and low temperatures. The results showed that the temporal variation trend of the CWSDI was significantly different at different growth periods of maize, and there were different trends and spatial modal distributions. However, the temporal variation trend of F(T) was similar, showing a downward trend over the entire region. There was no obvious asymmetry or skew‐dependent structure in the distribution of concurrent events of drought and low temperature; however, the joint probability contours of different growth periods were biased to the upper left. The recurrence period of drought and low‐temperature concurrent events was within 2 years, and the recurrence period was basically between 2 and 5 years, with a reduction in drought or low temperatures. [ABSTRACT FROM AUTHOR]

Few researchers have looked at the mechanical characteristics of rocks that are composed of numerous layers of various kinds of rock. Most strata in practical engineering are composite strata, and fracture propagation is frequently to blame for engineering mishaps. The digital image correlation method (DIC) and acoustic emission (AE) equipment were used to observe the crack strike and strain field changes of specimens that resemble rocks with a constructed joint under uniaxial compression in order to study the crack growth process and failure mode in composite rock strata under uniaxial compression. The research focus of this paper is to conduct a quantitative and qualitative analysis of crack types based on the data obtained from the DIC test. The covariance matrix was introduced to quantify the strain field dispersion of samples with joint dip angles α = 0°, 15°, 30°, 45°, 60°, and 75°. The outcomes of the analysis were as follows: the displacement data of the two crack sides were quantified using the novel method, and the crack types were determined to be tensile crack (type I), shear crack (type II), and composite tension–shear crack (type I–II); the covariance matrix-based parameter V can be used to describe the crack creation and spread process; and according to the growth rate of V, the crack types were identified as tensile crack (0.12 × 10−4–0.49 × 10−4), shear crack (1.17 × 10−4–4.5 × 10−4), and composite tension–shear crack (0.72 × 10−4–0.99 × 10−4). [ABSTRACT FROM AUTHOR]

An artificial basilar membrane (ABM) is an acoustic transducer that mimics the mechanical frequency selectivity of the real basilar membrane, which has the potential to revolutionize current cochlear implant technology. While such ABMs can be potentially realized using piezoelectric, triboelectric, and capacitive transduction methods, it remains notoriously difficult to achieve resistive ABM due to the poor frequency discrimination of resistive‐type materials. Here, a point crack technology on noncracking vertically aligned gold nanowire (V‐AuNW) films is reported, which allows for designing soft acoustic sensors with electric signals in good agreement with vibrometer output—a capability not achieved with corresponding bulk cracking system. The strategy can lead to soft microphones for music recognition comparable to the conventional microphone. Moreover, a soft resistive ABM is demonstrated by integrating eight nanowire‐based sensor strips on a soft trapezoid frame. The wearable ABM exhibits high‐frequency selectivity in the range of 319–1951 Hz and high sensitivity of 0.48–4.26 Pa−1. The simple yet efficient fabrication in conjunction with programmable crack design indicates the promise of the methodology for a wide range of applications in future wearable voice recognition devices, cochlea implants, and human–machine interfaces. [ABSTRACT FROM AUTHOR]

Sweat pH is a key health indicator related to metabolism and homeostasis level through hydrogen ion concentration in biological bio-fluid. Therefore, increasing research efforts have been directed to develop wearable pH sensors towards continuous non-invasive monitoring of sweat pH values in the out-of-hospital environments. Herein, we report a stretchable gold fiber-based electrochemical pH sensor based on our recently developed elastomer-bonded gold nanowire coating technology. The densely packed gold film offers superior strain-insensitive conductivity, high stretchability and large electrochemical active surface area (EASA). By electrodepositing polyamine (PANI) and Ag/AgCl onto the gold fibers, we could selectively detect the pH based on open circuit potentials in an ion-selective electrode design. The obtained fiber-based pH sensors feature a great sensitivity (60.6 mV per pH), high selectivity against cationic interference and high stretchability (up to 100% strain). One of the attributes for the fiber-based sensors is that they can be weaved into textiles, holding great potential for integration into everyday clothing for "unfeelable" personal health monitoring. [ABSTRACT FROM AUTHOR]

2 nm thin gold nanowires (AuNWs) have extremely high aspect ratio (≈10 000) and are nanoscale soft building blocks; this is different from conventional silver nanowires (AgNWs), which are more rigid. Here, highly sensitive, stretchable, patchable, and transparent strain sensors are fabricated based on the hybrid films of soft/hard networks. They are mechanically stretchable, optically transparent, and electrically conductive and are fabricated using a simple and cost-effective solution process. The combination of soft and more rigid nanowires enables their use as high-performance strain sensors with the maximum gauge factor (GF) of ≈236 at low strain (<5%), the highest stretchability of up to 70% strain, and the optical transparency is from 58.7% to 66.7% depending on the amount of the AuNW component. The sensors can detect strain as low as 0.05% and are energy efficient to operate at a voltage as low as 0.1 V. These attributes are difficult to achieve with a single component of either AuNWs or AgNWs. The outstanding sensing performance indicates their potential applications as 'invisible' wearable sensors for biometric information collection, as demonstrated in applications for detecting facial expressions, respiration, and apexcardiogram. [ABSTRACT FROM AUTHOR]

High transparency, conductivity and stretchability are very difficult to achieve simultaneously in a single type of capacitance device. Usually, high optical transparency requires very thin conductive film, which will inevitably cause cracking or breakage when a strain is applied. In this case, most of the currently developed electrodes are either transparent or stretchable but not both. Herein, we report a simple yet efficient method to fabricate self-assembled monolayer gold nanowires (AuNWs) conductive thin film. Such film is both transparent and stretchable due to the unique flexible hairy structure of ultrathin AuNWs (2 nm in diameter, aspect ratio >10,000). In addition, the resultant AuNWs film could be used as nanostructured electrode for transparent and stretchable supercapacitors. The entire supercapacitor showed a high transparency of 79 % at the wavelength of 550 nm, and could be stretched up to 30 % strain without degradation over 80 stretching cycles. [ABSTRACT FROM AUTHOR]

An ideal wearable/implantable bio‐diagnostics can be powered by second skin‐like energy devices in that they offer advantages such as conformal attachment/integration, lightweightness, and moduli‐matching properties. Past several years have witnessed encouraging progresses in soft stretchable supercapacitors by various material combinations and design strategies; however, it remains nontrivial to achieve highly flexible high‐performance supercapacitors in a skin‐thin layout yet with multifunctionality. Here, such a second skin‐like electrochromic supercapacitor is demonstrated using self‐assembled vertical gold nanowires (v‐AuNWs) and electrodeposited polyaniline (PANI). The v‐AuNW film is highly conductive yet offers great flexibility and deformability, while PANI plays a dual role in enhancing capacitance and as charge/discharge‐level indicator. The assembled supercapacitors offer superior skin‐conformability and could achieve an areal specific capacitance of 11.76 mF cm−2 (scan rate of 10 mV s−1) with high durability. A second skin‐like wearable tattoo energy device can be designed with negligible performance deterioration under multiple hand movements and skin deformations. A second skin‐like electrochromic supercapacitor is successfully fabricated using vertically aligned gold nanowires and electrodeposited polyaniline. The nanowire film is highly conductive with outstanding softness and skin‐conformability serving as a current collector, while polyaniline provides pseudocapacitance and serves as a charge/discharge‐level indicator. The supercapacitor exhibits negligible performance deterioration under various skin deformations. [ABSTRACT FROM AUTHOR]

Stretchable fiber conductors are appealing in the field of soft electronics due to their potential to be woven into fabrics leading to smart textile electronics. Coating highly conductive metal films onto elastic polymer fibers can be a potential strategy, however, it is nontrivial to achieve strong metal/polymer adhesion to avoid interfacial failure under large mechanical strains. Here, a novel moss‐inspired gold‐coating strategy by using an ultrathin gold nanowires (AuNWs)‐seeded electroless deposition strategy to fabricate stretchable fiber conductors in a dry spinning process is reported. By optimizing Hildebrand's and Hansen's solubility parameter, the AuNWs are dispersed well in an elastomer matrix leading to the efficient scalable production of AuNWs‐impregnated elastomeric fibers. Remarkably, these AuNWs can serve as "seeds" to promote conformal electroless deposition of gold films to substantially enhance the fiber conductivity. Such gold films resemble moss exhibiting strong adhesion to elastomeric polymer fibers because they have AuNWs roots embedded in the polymer matrix. With prestrained fibers, directional cracks along the axis are found, but they can be repaired reversibly when strains are reapplied. This leads to substantial conductivity enhancement. The fiber conductors can be woven into an everyday glove to exhibit superior strain‐insensitivity without changing the intensity of the light‐emitting diode under severe deformations. A moss‐inspired stretchable fiber conductor is fabricated in a dry spinning process together with a following ultrathin gold nanowires (AuNWs)‐seeded electroless deposition process. A seed‐root interfacial design of AuNWs and polymer enables the growth of gold films to enhance conductivity. The conductivity extraordinarily increases with the increase of strain in a large range, exhibiting significant potentials in wearable devices. [ABSTRACT FROM AUTHOR]

Traditional electrochemical biosensing electrodes (e.g., gold disk, glassy carbon electrode, etc.) can undergo sophisticated design to detect chemicals/biologicals from cells. However, such electrodes are typically rigid and nonstretchable, rendering it challenging to detect cellular activities in real-time and in situ when cells are in mechanically deformed states. Here, we report a new stretchable electrochemical cell-sensing platform based on vertically aligned gold nanowires embedded in PDMS (v-AuNWs/PDMS). Using H 2 O 2 as a model analyte, we show that the v-AuNWs/PDMS electrode can display an excellent sensing performance with a wide linear range, from 40 μM to 15 mM, and a high sensitivity of 250 mA/cm 2 /M at a potential of -0.3 V. Moreover, living cells can grow directly on our stretchable high-surface area electrodes with strong adhesion, demonstrating their excellent biocompatibility. Further cell stimulation by adding chemicals induced H 2 O 2 generation, which can be detected in real-time and in situ using our v-AuNWs/PDMS platform for both natural and stretched states of cells. Our results indicate the v-AuNWs/PDMS electrochemical biosensor may serve as a general cell-sensing platform for living organisms under deformed states.

The ability of developing highly durable fiber-shaped electronic devices is crucial for next-generation smart textile electronics. Past several years have witnessed encouraging progress made in stretchable fiber-shaped supercapacitors using carbon materials, transition metal oxides, and conducting polymers. Here, we report a dry-spun strategy to produce scalable ultrathin gold nanowire-based fibers, which can lead to highly stretchable fiber-based supercapacitors using a double-helix winding design. Hildebrand's and Hansen's solubility parameters of gold nanowire-binding oleylamine ligands match those of styrene-ethylene/butylene-styrene and tetrahydrofuran, enabling the formation of high-quality dry-spun fibers. In conjunction with conductivity enhancement by electroless plating and pseudocapacitance by polyaniline, we obtained fiber-shaped supercapacitors stretchable up to 360% with a capacitance of 16.80 mF cm -2 . The capacitance retention is about 85% after 2000 cycles of 0-200-0% stretching/releasing. Our fiber capacitors can be woven into an everyday glove, with negligible capacitance changes for normal finger movements.

Human skin can sense an external object in a location-specific manner, simultaneously recognizing whether it is sharp or blunt. Such tactile capability can be achieved in both natural and stretched states. It is impractical to mimic this tactile function of human skin by designing pixelated sensor arrays across our whole curvilinear human body. Here, we report a new tactile electronic skin sensor based on staircase-like vertically aligned gold nanowires (V-AuNWs). With a back-to-back linear or spiral assembly of two staircase structures into a single sensor, we are able to recognize pressure in a highly location-specific manner for both non-stretched and stretched states (up to 50% strain); with a concentric design on the fingertip, we can identify the sharpness of an external object. We believe that our strategy opens up a new route to highly specific second-skin-like tactile sensors for electronic skin (E-skin) applications.

Percolation networks of one-dimensional (1D) building blocks (e.g., metallic nanowires or carbon nanotubes) represent the mainstream strategy to fabricate stretchable conductors. One of the inherent limitations is the control over junction resistance between 1D building blocks in natural and strained states of conductors. Herein, we report highly stretchable transparent strain-insensitive conductors using fractal gold (F-Au) nanoframework based on a one-pot templateless wet chemistry synthesis method. The monolayered F-Au nanoframework (∼20 nm in thickness) can be obtained from the one-pot synthesis without any purification steps involved and can be transferred directly to arbitrary substrates like polyethylene terephthalate, food-wrap, polydimethylsiloxane (PDMS), and ecoflex. The F-Au thin film with no capping agents leads to a highly conductive thin film without any post-treatment and can be stretched up to 110% strain without significantly losing conductivity yet with the optical transparency of 70% at 550 nm. Remarkably, the F-Au thin film shows the strain-insensitive behavior up to 20% stretching strain. This originates from the unique fractal nanomesh-like structure which can absorb external mechanical forces, thus maintaining electron pathways throughout the nanoframework. In addition, a semitransparent bilayered F-Au film on 100% prestrained PDMS could achieve to a high stretchability of 420% strain with negligible resistance changes under low-level strains.