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The island‐bridge structural design is a common strategy for imparting stretchability to flexible electronic devices. In this structure, the low modulus regions bear most of the deformation, while the rigid islands, which house the electronic components, undergo minimal deformation. However, due to the modulus differences that can be several times or even several orders of magnitude larger, severe strain concentration occur at the edges of the rigid islands in high modulus regions. This strain concentration caused by rigid constraints not only reduces the stretchability of the soft substrate but also degrades the mechanical performance of the interconnected structures, thereby significantly affecting the overall stability of the device. Starting from finite element simulations, this paper introduces modulus gradient regions and optimizes geometric parameters, significantly alleviating the strain concentration at the edges of the rigid islands. Serpentine‐shaped circuits are then transferred to a substrate with strain isolation, which demonstrates better stretchability stability under 20% elongation compared to traditional strain isolation strategies. In addition, the stretchable light emitting diode (LED) system with gradient modulus has better stretchability compared to the system with conventional strategy. This suggests that this strategy has great potential in maintaining the stability of stretchable systems. [ABSTRACT FROM AUTHOR]

Strain engineering, as a non‐chemical tuning knob, can enhance the performance of semiconductor devices. Here, an efficient manipulation of light emission is revealed in thin‐layered 2D perovskite strongly correlated to layer numbers of [PbI6]4− octahedron (n) and [C6H5(CH2)2NH3]2(CH3NH3)n‐1PbnI3n+1 (N) by applying uniaxial strains (ɛ) via bending the flexible substrate. As increases from 1 to 3, an efficient light emission redshift (ɛ from −0.97% to 0.97%) is observed from bandgap shrinkage, and the shrinkage rate increases from 1.97 to 10.38 meV/%, which is attributed to the predominant uniaxial intralayer deformation due to the anisotropy of the [PbI6]4− octahedron lattice strain. Conversely, as increases from 7 to 48 for n = 3, the deformation related to bandgap shrinkage rate is more prominent in small‐N flakes ( ≈ 7, 15.2 meV/%) but is easily offset in large‐N flakes ( ≈ 48, 7.7 meV/%). This anisotropic lattice deformation, meanwhile, inevitably modulates the carrier recombination dynamics of [C6H5(CH2)2NH3]2(CH3NH3)n‐1PbnI3n+1, which is essential for the development of highly efficient photoelectronic devices. [ABSTRACT FROM AUTHOR]

A modified balanced ratio metric detection (BRD) system was proposed and applied in trace measurement of water vapor. Three features, including proportion of alternating current (AC) and direct current (DC) signals, environment temperature and light intensity ratio have been stated. Their influences on measured result have been analyzed. Meanwhile, techniques including adding filter, using integrated transistor and light intensity ratio adjustment and their effects for measurement improvement have been discussed. The absorption line was chosen at 1368.597 nm and the path length was 10 cm. With application of the above techniques, an accuracy of 5 ppm for water vapor concentration has been achieved. [ABSTRACT FROM AUTHOR]

• Vegetation greening is the major driver of ET and water resource risks. • Temperature mainly indirectly affected ET and water resource risks. • Water resource risks are concentrated in the middle and upper reaches of the YRB. • Water-saving should be prioritized in ecological restoration strategies. Quantifying the impacts of climate change, vegetation greening and human activities (CVH) on evapotranspiration (ET), surface drought intensity (ET divided by precipitation, SDI), and vegetation available water (precipitation minus ET, VAW) would improve our understanding of water cycle processes. The Yellow River Basin (YRB) is a significant climate-sensitive region in China, resulting in an obvious spatiotemporal heterogeneity of ET, SDI, and VAW in response to driving variables. In this study, we analysed the spatiotemporal variation characteristics of ET, SDI, and VAW in the YRB from 1984 to 2018. We also quantified the direct and indirect contributions of the CVH to the changes in ET, SDI, and VAW, and revealed the influence mechanism of each link. Finally, water resource risks were assessed from a probabilistic perspective. The results indicated that vegetation greening was the primary driver of ET with an increase rate of 1.60 mm/a, which was also the most important influencing factor of SDI increase and VAW decrease. Leaf area index (LAI) and relative humidity (RH) jointly dominated the ET changes in 66 % of the YRB, temperature (Temp) dominated the SDI changes in nearly half of the basin, precipitation (Pre) and LAI jointly dominated the VAW changes in 66 % of the YRB. Temp indirectly influenced ET primarily through LAI, whereas LAI primarily influenced ET directly. Temp had a significant direct impact on SDI, while LAI mainly influenced SDI through RH and wind speed (WS). Temp exhibited the most substantial negative influence on VAW. LAI was identified as the primary factor contributing to water resource risks, with a probability reaching 0.8, while the probabilities associated with other factors inducing such risks were similar at the basin level, but disparities existed among different land use types. The findings of the study significantly enhanced our understanding of the role that the CVH played in hydrological processes, serving as a crucial foundation for achieving a balance between ecological restoration and socio-economic development in the YRB. [ABSTRACT FROM AUTHOR]

We present a theoretical model to analyze the impact of Rayleigh noise on Raman distributed temperature sensors (RDTS), which use the anti-Stokes and Stokes light or anti-Stokes component only as the demodulation signals. Based on this model, the effects of Rayleigh noise on temperature accuracy, sensitivity, and resolution are investigated both at only one point and in a section of the fiber. The analysis indicates that for RDTS demodulated by anti-Stokes light only, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.25°C on the assumption that the Rayleigh noise accounts for 10% of the anti-Stokes intensity. Moreover, for RDTS demodulated by Stokes and anti-Stokes light, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.2°C assuming that the Rayleigh noise in two paths is equal to 10% of the intensity of anti-Stokes and Stokes light. The analysis demonstrates that the impact of Rayleigh noise on sensing capacities of RDTS is non-negligible, thus providing a major contribution to the elimination of Rayleigh noise in RDTS. [ABSTRACT FROM AUTHOR]