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Ground-based positioning systems are necessary as the conventional satellite-based systems suffer from weak received signals. In this paper, we proposed a precise ranging method in single-carrier frequency domain equalization (SC-FDE) system using the amplitude nonlinearity of oversampled signals.A new pattern of the preamble and the unique word was designed for SC-FDE system, where the preamble can be exploited in correlation-based timing algorithm to obtain impulse-like timing metric. Combining with the coarse timing procedure, we proposed a fine ranging method relying on the oversampled signals in SC-FDE receiver employing Qth-power nonlinearity, and then analyzed its estimation mean and variance. The extensive simulations were conducted to validate the proposed method with distinct modulation schemes, rolling-off factors, block lengths, and nonlinearity factors. The results show that the proposed ranging method can achieve unbiased estimate and its root mean square errors will reach the order of centimeter at medium-to-high signal-to-noise ratio region in flat-fading channels, whereas the observed performance degradation in frequency selective channel can be mitigated by using equalized oversampled signals.

Fingerprints are still one of the most powerful and important means of biometric identification. This paper presents a green and fast electrochemical method for improved development of latent fingerprints (LFPs) on five kinds of commonly encountered conductive substrates by the use of spatial selective electrodeposition of graphene nanosheets. Since secretions produced in the fingerprint deposit lead the underlying surface to be electrochemically inert or less active, the electrodeposition process only occurs on the areas without fingerprint residue. As a result, a high contrast negative image of the fingerprint was achieved by the electrochemical reduction of graphene oxide (GO) after optimizing the factors (applied potential, deposition time and scan rate).

A time-domain ranging algorithm is proposed for a frequency-modulated continuous wave (FMCW) short-range radar sensor with high accuracy and low complexity. The proposed algorithm estimates the distance by calculating the ratio of the beat frequency signal to its derivative and thereby eliminates the restriction of frequency bandwidth on ranging accuracy. Meanwhile, we provide error analysis of the proposed algorithm under different distances, integral lengths, relative velocities, and signal-to-noise ratios (SNRs). Finally, we fabricate FMCW sensor prototype and construct a measurement system. Testing results demonstrate that the proposed time-domain algorithm could achieve range error within 0.8 m. Compared with the conventional fast Fourier transform (FFT) estimation scheme, the proposed method performs ranging without the requirement of complex multiplications, which makes it reasonable to be implemented in real-time and low-cost systems.

We demonstrate a facile method termed candle soot coating (CSC) for fast developing latent fingermarks (LFMs) on various kinds of surfaces (glass, ceramic, metal, paper and adhesive tape). The CSC method can be considered as simple, fast, and low-cost as well as providing high contrast for LFM visualization in potential forensic applications.

Biofabricated nanostructured and microstructured scaffolds have exhibited great potential for nerve tissue regeneration and functional restoration, and prevascularization and biotransportation within 3D fascicle structures are critical. Unfortunately, an ideal internal fascicle and microvascular model of human peripheral nerves is lacking. In this study, we used microcomputed tomography (microCT) to acquire high‐resolution images of the human sciatic nerve. We propose a novel deep‐learning network technique, called ResNetH3D‐Unet, to segment fascicles and microvascular structures. We reconstructed 3D intraneural fascicles and microvascular topography to quantify the fascicle volume ratio (FVR), microvascular volume ratio (MVR), microvascular to fascicle volume ratio (MFVR), fascicle surface area to volume ratio (FSAVR), and microvascular surface area to volume ratio (MSAVR) of human samples. The frequency distributions of the fascicle diameter, microvascular diameter, and fascicle‐to‐microvasculature distance were analyzed. The obtained microCT analysis and reconstruction provided high‐resolution microstructures of human peripheral nerves. Our proposed ResNetH3D‐Unet method for fascicle and microvasculature segmentation yielded a mean intersection over union (IOU) of 92.1% (approximately 5% higher than the U‐net IOU). The 3D reconstructed model showed that the internal microvasculature runs longitudinally within the internal epineurium and connects to the external vasculature at some points. Analysis of the 3D data indicated a 48.2 ± 3% FVR, 23.7 ± 1.8% MVR, 4.9 ± 0.5% MFVR, 7.26 ± 2.58 mm‐1 FSAVR, and 1.52 ± 0.52 mm‐1 MSAVR. A fascicle diameter of 0.98 mm, microvascular diameter of 0.125 mm, and microvasculature‐to‐fascicle distance of 0.196 mm were most frequent. This study provides fundamental data and structural references for designing bionic scaffolding constructs with 3D microvascular and fascicle distributions.

In this paper, based on the fabricated wall panel used in original modular indoor substation, the optimal design of sound insulation property is conducted according to the relevant theoretical basis of sound insulation properties of wall panels, and the reverberation room method is used to test and study original and new wall panels. The study shows that the sound insulation of the sandwich panel after optimization has been greatly improved in both medium, low and high frequency areas, with obvious optimal design effect, and also there are significant engineering application value and social benefits in the noise control of substation.

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