Interminable surveillance and reconnaissance through various sophisticated multispectral detectors present threats to military equipment and manpower. However, a combination of detectors operating in different wavelength bands (from hundreds of nanometers to centimeters) and based on different principles raises challenges to the conventional single-band camouflage devices. In this paper, multispectral camouflage is demonstrated for the visible, mid-infrared (MIR, 3–5 and 8–14 μm), lasers (1.55 and 10.6 μm) and microwave (8–12 GHz) bands with simultaneous efficient radiative cooling in the non-atmospheric window (5–8 μm). The device for multispectral camouflage consists of a ZnS/Ge multilayer for wavelength selective emission and a Cu-ITO-Cu metasurface for microwave absorption. In comparison with conventional broadband low emittance material (Cr), the IR camouflage performance of this device manifests 8.4/5.9 °C reduction of inner/surface temperature, and 53.4/13.0% IR signal decrease in mid/long wavelength IR bands, at 2500 W ∙ m−2 input power density. Furthermore, we reveal that the natural convection in the atmosphere can be enhanced by radiation in the non-atmospheric window, which increases the total cooling power from 136 W ∙ m−2 to 252 W ∙ m−2 at 150 °C surface temperature. This work may introduce the opportunities for multispectral manipulation, infrared signal processing, thermal management, and energy-efficient applications.

High-temperature infrared (IR) camouflage is crucial to the effective concealment of high-temperature objects but remains a challenging issue, as the thermal radiation of an object is proportional to the fourth power of temperature (T 4). Here, we experimentally demonstrate high-temperature IR camouflage with efficient thermal management. By combining a silica aerogel for thermal insulation and a Ge/ZnS multilayer wavelength-selective emitter for simultaneous radiative cooling (high emittance in the 5-8 μm non-atmospheric window) and IR camouflage (low emittance in the 8-14 μm atmospheric window), the surface temperature of an object is reduced from 873 to 410 K. The IR camouflage is demonstrated by indoor/outdoor (with/without earthshine) radiation temperatures of 310/248 K for an object at 873/623 K and a 78% reduction in with-earthshine lock-on range. This scheme may introduce opportunities for high-temperature thermal management and infrared signal processing.

Outdoor personal thermal comfort is of substantial significance to ameliorate the health conditions of pedestrian and outdoor laborer. However, the uncontrollable sunlight, substantial radiative loss, and intense temperature fluctuations in the outdoor environment present majestic challenges to outdoor personal thermal management. Here, we report an eco-friendly passive nanostructured textile which harvests energy from the sun and the outer space for optional localized heating and cooling. Compared to conventional heating/cooling textiles like black/ white cotton, its heating/cooling mode enables a skin simulator temperature increase/decrease of 8.1 °C/6 °C, respectively, under sunlight exposure. Meanwhile, the temperature gradient created between the textile and human skin allows a continuous electricity generation with thermoelectric modules. Owing to the exceptional outdoor thermoregulation ability, this Janus textile is promising to help maintain a comfortable microclimate for individuals in outdoor environment and provide a platform for pervasive power generation.

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Cataloged from PDF version of article.Inkjet-printed In-Ga-Zn oxide (IGZO) thin-film transistors (TFTs) with bottom-gate bottom-contact device architecture are studied in this paper. The impact of the IGZO film thickness on the performance of TFTs is investigated. The threshold voltage, field-effect mobility, on and off drain current, and subthreshold swing are strongly affected by the thickness of the IGZO film. With the increase in film thickness, the threshold voltage shifted from positive to negative, which is related to the depletion layer formed by the oxygen absorbed on the surface. The field-effect mobility is affected by the film surface roughness, which is thickness dependent. Our results show that there is an optimum IGZO thickness, which ensures the best TFT electrical performance. The best result is from a 55-nm-thick IGZO TFT, which showed a field-effect mobility in the saturation region of 1.41 cm(2)/V . s, a threshold voltage of 1 V, a drain current on/off ratio of approximately 4.3 x 10(7), a subthreshold swing of 384 mV/dec, and an off-current level lower than 1 pA

Control of thermal emission underpins fundamental science, as it is related to both heat and infrared electromagnetic wave transport. However, realizing nonvolatile reconfigurable thermal emission is challenging due to the inherent complexity or limitation in conventional radiative materials or structures. Here, we experimentally demonstrate a nonvolatile optically reconfigurable mid-infrared coding radiative metasurface. By applying laser pulses, infrared emissive patterns are directly encoded into an ultrathin (∼25 nm) Ge2Sb2Te5 layer integrated into a planar optical cavity with the optically crystallized Ge2Sb2Te5 spots, and the peak spectral emissivity is repeatedly switched between low (∼0.1) and high (∼0.7) values. In addition, the visible scattering patterns are independently modulated with submicron-sized bumps generated by high-power laser pulses. An anticounterfeiting label is demonstrated with spatially different infrared emission and visible light scattering information encoded. This approach constitutes a new route toward thermal emission control and has broad applications in encryption, camouflage, and so on.

Achieving light-driven motions in nonliquid environments presents formidable challenges, because microsized objects experience strong dry adhesion and intend to be stuck to contact surfaces with great tenacity. Here, in air and vacuum, we show rotary locomotion of a micrometer-sized metal plate with ~30 nm thickness, revolving around a microfiber. This motor is powered by pulsed light guided into the fiber as a coordinated consequence of an optically excited Lamb wave on the plate and favorable configuration of plate-fiber geometry. The motor, actuated by designed light pulses, crawls stepwise with subnanometer locomotion resolution. Furthermore, we can control the rotation velocity and step resolution by varying the repetition rate and pulse power, respectively. A light-actuated micromirror scanning with 0.001° resolution is then demonstrated on the basis of this motor. It offers unprecedented application potential for integrated micro-opto-electromechanical systems, outer-space all-optical precision mechanics and controls, and laser scanning for miniature lidar systems.

Given the limitation of traditional univariate analysis method in processing the multicollinearity of dam monitoring data, this paper reconstructs the multivariate response variables by introducing principal component analysis (PCA) method, explores the ways of determining principal components (PCs), and extracts a few PCs that have major influence on data variance. For steady observation series, a control field for the whole observation values has been established based upon PCA; for unsteady observation series that have significant tendency, a control field for the future observation values has been constructed according to PC statistical predication model. These methods have already been applied to an actual project and the results showed that data interpretation method with PCA can not only realize data reduction, lower data redundancy, and reduce noise and false alarm rate, but also be effective to data analysis, having a broad application prospect. dam safety monitoring, multivariate response variables, principal component analysis, data reduction Citation:Yu H, Wu Z R, Bao T F, et al. Multivariate analysis in dam monitoring data with PCA.