An asymmetrical three state switching boost (TSSB) converter combining the benefits of magnetic coupling and voltage multiplier techniques is presented in this paper. The derivation procedure for the proposed topology is depicted. The new converter can achieve very high voltage gain and very low voltage stress on the power devices without high turn ratio and extreme duty cycles. Thus, the low voltage rated MOSFETs with low resistance rDS(ON) can be selected to reduce the switching losses and cost. Moreover, the usage of voltage multiplier technique not only raises the voltage gain but also offers lossless passive clamp performance, so the voltage spikes across the main switches are alleviated and the leakage-inductor energy of the coupled-inductors can be recycled; Also, the interleaved structure is employed in the input side, which not only reduces the current stress through each power switch, but also constrains the input current ripple. In addition, the reverse-recovery problem of the diodes is alleviated, and the efficiency can be further improved. The operating principles and the steady-state analysis of the presented converter are discussed in detail. Finally, a prototype circuit with 400W nominal rating is implemented in the laboratory to verify the performance of the proposed converter.Index Term-Three state switching high gain boost converter magnetic coupling voltage multiplier. Manuscript

Soft self-healing materials are compelling candidates for stretchable devices because of their excellent compliance, extensibility, and self-restorability. However, most existing soft self-healing polymers suffer from crack propagation and irreversible fatigue failure due to easy breakage of their dynamic amorphous, low-energy polymer networks. Herein, inspired by distinct structure-property relationship of biological tissues, a supramolecular interfacial assembly strategy of preparing soft self-healing composites with unprecedented crack propagation resistance is proposed by structurally engineering preferentially aligned lamellar structures within a dynamic and superstretchable poly(urea-ureathane) matrix (which is elongated to 24 750× its original length). Such a design affords a world-record fracture energy (501.6 kJ m −2 ), ultrahigh fatigue threshold (4064.1 J m −2 ), and outstanding elastic restorability (dimensional recovery from 13 times elongation), and preserving low modulus (1.2 MPa), high stretchability (3200%), and high room-temperature self-healing efficiency (97%). Thereby, the resultant composite represents the best of its kind and even surpasses most biological tissues. The lamellar 2D transition-metal carbide/carbonitride (MXene) structure also leads to a relatively high in-plane thermal conductivity, enabling composites as stretchable thermoconductive skins applied in joints of robotics to thermal dissipation. The present work illustrates a viable approach how autonomous self-healing, crack tolerance, and fatigue resistance can be merged in future material design.

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A fiber-optic intrinsic distributed acoustic emission (AE) sensor is proposed. By measuring the time delay of two signals from two Mach-Zehnder interferometers, the location of AE can be deduced, and the corresponding sensor is experimentally verified to be feasible with a 206 m average location error in a 20 km sensing range, which shows that this proposed sensor is applicable for distributed AE sensing for large structure health monitoring, with the unique advantages of low cost, simple configuration, and long sensing range. The limitations of the proposed sensor are also discussed, and the future work is presented.

The achievement of perfect light absorption in ultrathin semiconductor materials is not only a long‐standing goal, but also a critical challenge for solar energy applications, and thus requires a redesigned strategy. Here, a general strategy is demonstrated both theoretically and experimentally to create a planar metasurface absorber comprising a 1D ultrathin planar semiconductor film (replacing the 2D array of subwavelength elements in classical metasurfaces), a transparent spacer, and a metallic back reflector. Guided by derived formulisms, a new type of macroscopic planar metasurface absorber is experimentally demonstrated with light near‐perfectly and exclusively absorbed by the ultrathin semiconductor film. To demonstrate the power and simplicity of this strategy, a prototype of a planar metasurface solar cell is experimentally demonstrated. Furthermore, the device model predicts that a colored planar metasurface perovskite solar cell can maintain 75% of the efficiency of its black counterpart despite the use of a perovskite film that is one order of magnitude thinner. The displayed cell colors have high purities comparable to those of state‐of‐the‐art color filters, and are insensitive to viewing angles up to 60°. The general theoretical framework in conjunction with experimental demonstrations lays the foundation for designing miniaturized, planar, and multifunctional solar cells and optoelectronic devices.

Diabetes mellitus, especially type 2 diabetes mellitus (T2DM), has become a significant public health burden. Rhizoma coptidis (RC), known as Huang Lian , is widely used for treating diabetes in China. The bioactive compounds of RC, especially alkaloids, have the potential to suppress T2DM-induced lesions, including diabetic vascular dysfunction, diabetic heart disease, diabetic hyperlipidemia, diabetic nephropathy, diabetic encephalopathy, diabetic osteopathy, diabetic enteropathy, and diabetic retinopathy. This review summarizes the effects of RC and its bioactive compounds on T2DM and T2DM complications. Less research has been conducted on non-alkaloid fractions of RC, which may exert synergistic action with alkaloids. Moreover, we summarized the pharmacokinetic properties and structure-activity relationships of RC on T2DM with reference to extant literature and showed clearly that RC has potential therapeutic effect on T2DM.

Many standardized educational tests include groups of items based on a common stimulus, known as testlets. Standard unidimensional item response theory (IRT) models are commonly used to model examinees' responses to testlet items. However, it is known that local dependence among testlet items can lead to biased item parameter estimates when using standard IRT models, and to overestimated reliability. In this study, a general polytomous testlet model was proposed to account for local dependence in testlet-based tests that contain both dichotomously and polytomously scored items. The proposed model and a standard IRT model were fit to simulated data and several real data sets from the reading sections of a large-scale Englishlanguage test, and model fit was evaluated. Item parameters and test information obtained from the two models were compared to check the impact of local item dependence. In addition, a multidimensional IRT model with simple structure was also fit to the real data sets. Results based on both simulated and real data suggested that local dependence had a small impact on item parameter estimates and a relatively larger impact on test information and reliability. It was also found that the multidimensional IRT model with simple structure fit the real data sets better than the general polytomous testlet model and the standard IRT model did.

A new planar antenna is proposed for multiple applications in ground‐penetrating radar. The proposed antenna offers ultra‐wide band characteristics ranging from 100 MHz to 6 GHz. The antenna composed of two elements: an electrical tree‐shaped portion and a magnetic loop antenna, made by joining an electrical antenna with a ground plane via 50 Ohm resistor. The loop antenna portion provides a low‐frequency operation without increasing physical size of the antenna. Proposed antenna has relatively small dimensions 20 × 22.5 cm2 as compared with similar antennas covering the same bandwidth. Time domain analysis of this antenna is done to check its performance for applications in impulse‐based radar systems. The antenna has been manufactured and experimental results are added to validate simulation results.