Flexible pressure sensors have attracted intense attention because of their widespread applications in electronic skin, human−machine interfaces, and healthcare monitoring. Conductive porous structures are always utilized as active layers to improve the sensor sensitivities. However, flexible pressure sensors derived from traditional foaming techniques have limited structure designability. Besides, random pore distribution causes difference in structure and signal repeatability between different samples even in one batch, therefore limiting the batch production capabilities. Herein, we introduce a structure designable lattice structure pressure sensor (LPS) produced by bottom-up digital light processing (DLP) 3D printing technique, which is capable of efficiently producing 55 high fidelity lattice structure models in 30 min. The LPS shows high sensitivity (1.02 kPa −1 ) with superior linearity over a wide pressure range (0.7 Pa to 160 kPa). By adjusting the design parameters such as lattice type and layer thickness, the electrical sensitivities and mechanical properties of LPS can be accurately controlled. In addition, the LPS endures up to 60000 compression cycles (at 10 kPa) without any obvious electrical signal degradation. This benefits from the firm carbon nanotubes (CNTs) coating derived from high-energy ultrasonic probe and the subsequent thermal curing process of UV-heat dual-curing photocurable resin. For practical applications, the LPS is used for real time pulse monitoring, voice recognition and Morse code communication. Furthermore, the LPS is also integrated to make a flexible 4 × 4 sensor arrays for detecting spatial pressure distribution and a flexible insole for foot pressure monitoring.

As a novel modality of molecular imaging, bioluminescence tomography (BLT) is used to in vivo observe and measure the biological process at cellular and molecular level in small animals. The core issue of BLT is to determine the distribution of internal bioluminescent sources from optical measurements on external surface. In this paper, a new algorithm is presented for BLT source reconstruction based on adaptive hp-finite element method. Using adaptive mesh refinement strategy and intelligent permissible source region, we can obtain more accurate information about the location and density of sources, with the robustness, stability and efficiency improved. Numerical simulations and physical experiment were both conducted to verify the performance of the proposed algorithm, where the optical data on phantom surface were obtained via Monte Carlo simulation and CCD camera detection, respectively. The results represent the merits and potential of our algorithm for BLT source reconstruction.

This paper presents an energy detection Impulse Radio Ultra-Wideband (IR-UWB) receiver for Radio Frequency Identification (RFID) and Wireless Sensor Networks (WSN) applications. An Application-Specific Integrated Circuit (ASIC) consisting of a 3-5 GHz analog front-end, a timing circuit and a high speed baseband controller is implemented in a 90 nm standard CMOS technology. A Field-Programmable Gate Array (FPGA) is employed as a reconfigurable back-end, enabling adaptive baseband algorithms and ranging estimations. The proposed architecture is featured by high flexibility that adopts a wide range of pulse rate (512 kHz-33 MHz), processing gain (0-18 dB), correlation schemes, synchronization algorithms, and modulation schemes (PPM/OOK). The receiver prototype was fabricated and measured. The power consumption of the ASIC is 16.3 mW at 1 V power supply, which promises a minimal energy consumption of 0.5 nJ/bit. The whole link is evaluated together with a UWB RFID tag. Bit error rate (BER) measurement displays a sensitivity of 79 dBm at 10 Mb/s with BER achieved by the proposed receiver, corresponding to an operation distance over 10 meters under the FCC regulation.Index Terms-Energy detection, Internet-of-Things, low power receiver, sensitivity, ultra-wideband (UWB).

A catalytic asymmetric [3 + 2] cycloaddition of 2-indolylmethanols with α,β-unsaturated aldehydes was developed for the first time. This transformation was achieved by a synergistic catalytic system consisting of a palladium complex, a Brønsted acid, and a chiral secondary amine to synthesize biologically active cyclopenta­[b]­indole derivatives with excellent diastereo- and enantioselectivities (up to >20:1 dr, up to 99% ee).

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