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Interactions between the microbiota and their colonized environments mediate critical pathways from biogeochemical cycles to homeostasis in human health. Here we report a soil-inspired chemical system that consists of nanostructured minerals, starch granules and liquid metals. Fabricated via a bottom-up synthesis, the soil-inspired chemical system can enable chemical redistribution and modulation of microbial communities. We characterize the composite, confirming its structural similarity to the soil, with three-dimensional X-ray fluorescence and ptychographic tomography and electron microscopy imaging. We also demonstrate that post-synthetic modifications formed by laser irradiation led to chemical heterogeneities from the atomic to the macroscopic level. The soil-inspired material possesses chemical, optical and mechanical responsiveness to yield write-erase functions in electrical performance. The composite can also enhance microbial culture/biofilm growth and biofuel production in vitro. Finally, we show that the soil-inspired system enriches gut bacteria diversity, rectifies tetracycline-induced gut microbiome dysbiosis and ameliorates dextran sulfate sodium-induced rodent colitis symptoms within in vivo rodent models.

Summary Designing materials with high Li to Na selectivity is the key for direct extraction of Li from unconventional sources, such as seawater, without complex separations. However, material discovery is hindered by an insufficient understanding on how a material's composition and structure relate to Li selectivity during electrochemical co-intercalation. Here, we synthesized a core-shell structured (NaLi)1−xCoO2 with a core Li phase (Li0.94CoO2), a shell Na phase (Na0.51CoO2), and a transition intermediate phase via Na ion-exchange of parent Li1−xCoO2. We reveal that the chemical compositions and spatial relation of these phases play critical roles in governing high Li to Na selectivity. The core Li phase restricts large layer spacing expansion and inhibits Na intercalation. The shell Na phase serves to maintain the electrode stability against further Na ion exchange. With the layer spacing gradient design, we achieved a high Li selectivity of 1.5 × 105 with a recovery of ∼7.6:1 Li to Na from 1:20,000 initial ratio.

In the ever-changing market environment, rigid production facilities and large bulk mode are becoming less and less able to cater to the trend. The demand for small-batch flexible automation production is becoming more and more urgent for enterprise, so the research on flexible assembly automation has attracted more and more attention. This paper proposes a reconfigurable flexible assembly line that can be used in actual production. Based on the type II robotic assembly line balancing problem model, for an actual production hydraulic valve product, we propose a mathematical model including cycle time CT, assembly tool replacement time RT and the assembly cell cost ST, then carry out the pre-optimization operator, and use the dual-population genetic algorithm to solve the problem to obtain a well-balanced assembly line layout, then guide the actual production.

To resolve the problem of structure management in Unmanned Aerial Vehicle(UAV) formation, a dynamic weight values weighted clustering algorithm(DWVWCA) is proposed in this article, in which the cluster scheme for network optimization is used. Firstly, the residual energy model is improved to be more realistic. Secondly, the combined weighting method is introduced to make the comprehensive weight value of the UAV subjective and objective. Finally, the dynamic weight threshold is introduced to calculate the comprehensive weight value in real-time. The simulation results show that DWVWCA can effectively improve the objectivity of cluster head election, extend the UAV formation survival cycle, balance the network structure, reduce the number of cluster reorganization and fusion, and enhance the network stability.

Laser-assisted synthesis yields silicon carbide–elastomer composite for bioelectric modulation of cells and tissues., Conducting or semiconducting materials embedded in insulating polymeric substrates can be useful in biointerface applications; however, attainment of this composite configuration by direct chemical processes is challenging. Laser-assisted synthesis has evolved as a fast and inexpensive technique to prepare various materials, but its utility in the construction of biophysical tools or biomedical devices is less explored. Here, we use laser writing to convert portions of polydimethylsiloxane (PDMS) into nitrogen-doped cubic silicon carbide (3C-SiC). The dense 3C-SiC surface layer is connected to the PDMS matrix via a spongy graphite layer, facilitating electrochemical and photoelectrochemical activity. We demonstrate the fabrication of arbitrary two-dimensional (2D) SiC-based patterns in PDMS and freestanding 3D constructs. To establish the functionality of the laser-produced composite, we apply it as flexible electrodes for pacing isolated hearts and as photoelectrodes for local peroxide delivery to smooth muscle sheets.

© 2020 SPIE. Multimode polymer waveguides have attracted considerable interest for use in high-speed on-board communication links as they provide low loss (40 GHz×m) and can be cost-effectively integrated onto standard PCBs. The fabrication of such waveguides on flexible substrates can provide additional advantages: shape flexibility, lightweight and reduced thickness which are particularly important in the aviation and automotive industries. Such flexible and lightweight optical connections will play an important role in next-generation airplanes and driverless cars connecting the multitude of peripheral sensors with the central processing unit at high speed and low latency. However, in such applications, flexible polymer waveguides are required to be bent to meet their stringent space requirements and twisted or stretched when connecting movable parts. Under sharp flexure, the bending or twisting loss dominates the waveguide loss limiting their practical use. In this work therefore, we present a new waveguide design for flexible polymer waveguides with improved bending performance and derive useful layout rules for minimizing twisting losses in such samples. The proposed waveguide structure only requires one additional fabrication step and achieves bending losses below 0.5 dB for a 3 mm bend. In comparison, the conventional waveguide design yields a 2 dB loss under the same bending radius and launch condition. Additionally, useful equations relating the maximum allowed number of twisting turns for low excess loss with sample thickness and width are proposed. Bending and twisting measurements on flexible waveguide samples are presented validating these methods and demonstrating the potential of this technology.

Optically actuated silicon structures reveal rapid calcium signal propagation in biofilms., Bacterial response to transient physical stress is critical to their homeostasis and survival in the dynamic natural environment. Because of the lack of biophysical tools capable of delivering precise and localized physical perturbations to a bacterial community, the underlying mechanism of microbial signal transduction has remained unexplored. Here, we developed multiscale and structured silicon (Si) materials as nongenetic optical transducers capable of modulating the activities of both single bacterial cells and biofilms at high spatiotemporal resolution. Upon optical stimulation, we capture a previously unidentified form of rapid, photothermal gradient–dependent, intercellular calcium signaling within the biofilm. We also found an unexpected coupling between calcium dynamics and biofilm mechanics, which could be of importance for biofilm resistance. Our results suggest that functional integration of Si materials and bacteria, and associated control of signal transduction, may lead to hybrid living matter toward future synthetic biology and adaptable materials.

This paper proposes a combined Convolutional Neural Network (CNN) scheme appropriate for automatic modulation recognition. The suggested network includes a deep network involving multiscale convolutions with an attention module for recognizing 24 modulation modes and a shallow one network for recognizing two modulation modes, aiming to reduce the misjudgment caused by the deeper network. We evaluate our proposed network on the DeepSig dataset achieving an accuracy of 98.7% that exceeds the performance of current state-of-the-art (SOTA) methods exploiting this dataset. The network achieved almost 100% accuracy on modulation modes of the order less than or equal to 64 and under high SNR. The accuracy attained by our method on high-order modulation modes exceeds the one of ResNet, which currently is the SOTA method.

Optical interconnects play an important role in enabling high-speed short-reach communication links within next-generation high-performance electronic systems. Multimode polymer waveguides in particular allow the formation of high-capacity optical backplanes and cost-effective board-level optical interconnects. Their formation on flexible substrates offers significant practical advantages and enables their deployment in environments where shape and weight conformity become particularly important, such as in cars and aircraft. However, bending and twisting of flexible multimode waveguides can have a significant effect on their optical transmission performance due to mode loss and mode coupling. Moreover, the magnitude of the induced effects strongly depends on the launch conditions employed. In this paper, therefore, we present detailed loss, crosstalk, and bandwidth studies on flexible multimode waveguide arrays for different launch conditions regarding their use in real-world systems. The minimum radius to achieve a 1 dB excess bending loss is obtained for each launch condition as well as the crosstalk degradation due to bending. It is shown that for a 50 μm MMF input, a 6 mm bending radius is required for excess losses below 1 dB, while crosstalk below −35 dB is obtained in adjacent waveguides even under strong bending. Moreover, it is found that twisting has a small effect on the loss and crosstalk performance of the samples. Excess twisting loss less than 0.1 dB and crosstalk of −40 dB are obtained for three full 360° turns under a 50 μm MMF launch. Finally, the bandwidth studies carried out on the samples indicate than no significant bandwidth degradation is induced due to sample bending, with bandwidth-length product values larger than 150 GHz × m obtained for restricted launches. The set of results presented herein specify the deployment of this flexible polymer multimode waveguide technology in real-world systems and demonstrate its strong potential to implement low-loss high-bandwidth optical interconnects.

Engineered silicon-based materials can display photoelectric and photo-thermal responses under light illumination, which may lead to further innovations at the silicon–biology interfaces. Silicon nanowires have small radial dimensions, promising as highly localized cellular modulators, however the single crystalline form typically has limited photothermal efficacy due to the poor light absorption and fast heat dissipation. In this work, we report strategies to improve the photothermal response from silicon nanowires by introducing nanoscale textures on the surface and in the bulk. We next demonstrate high-resolution extracellular modulation of calcium dynamics in a number of mammalian cells including glial cells, neurons, and cancer cells. The new materials may be broadly used in probing and modulating electrical and chemical signals at the subcellular length scale, which is currently a challenge in the field of electrophysiology or cellular engineering.

We have prepared nanocrystals of MoS2 across a range of length scales by heating single crystals of the molecular precursor (NH4)2Mo3S13·H2O. Rod-shaped crystals of the polysulfide precursor retain their original morphology after heating at temperatures up to 1000 °C and undergo complete conversion to MoS2 while acting as a template for the confined formation of MoS2 nanocrystals. This solid state transformation proceeds with the release of gaseous species without blowing the crystals apart and leads to formation of pores embedded into a nanocrystalline assembly of the templated nano-MoS2. The obtained assemblies of MoS2 nanocrystals have the exact same shape of the original rod-shaped (NH4)2Mo3S13·H2O crystals indicative of a pseudomorphic shape-retentive process. Such crystal-shaped nanocrystal assemblies show electrical conductivity values similar to a bulk MoS2 single crystal with electron carrier concentration of 1.5 × 1014 cm–3 and mobility of 7 cm2/(V s). The nanocrystals of MoS2 were grown at temp...

Silicon-based materials have been widely used. However, remotely controlled and interconnect-free silicon configurations have been rarely explored, because of limited fundamental understanding of the complex physicochemical processes that occur at interfaces between silicon and biological materials. Here, we describe rational design principles, guided by biology, for establishing intracellular, intercellular and extracellular silicon-based interfaces, where the silicon and the biological targets have matched properties. We focused on light-induced processes at these interfaces, and developed a set of matrices to quantify and differentiate the capacitive, Faradaic and thermal outputs from about 30 different silicon materials in saline. We show that these interfaces are useful for the light-controlled non-genetic modulation of intracellular calcium dynamics, of cytoskeletal structures and transport, of cellular excitability, of neurotransmitter release from brain slices, and of brain activity in vivo.

AlN/GaN-based optoelectronic devices have been the subject of intense research underlying the commercialization of efficient devices. Areas of considerable interest are the study of their lattice dynamics, phonon transport, and electron-phonon interactions specific to the interface of these heterostructures which results in additional optical phonon modes known as interface phonon modes. In this study, the framework of the dielectric continuum model (DCM) has been used to compare and analyze the optical phonon modes obtained from experimental Raman scattering measurements on AlN/GaN short-period superlattices. We have observed the localized E2(high), A1(LO) and the E1(TO) modes in superlattice measurements at frequencies shifted from their bulk values. To the best of our knowledge, the nanostructures used in these studies are among the smallest yielding useful Raman signatures for the interface modes. In addition, we have also identified an additional spread of interface phonon modes in the TO range resulting from the superlattice periodicity. The Raman signature contribution from the underlying AlxGa1-xN ternary has also been observed and analyzed. A temperature calibration was done based on Stokes/anti-Stokes ratio of A1(LO) using Raman spectroscopy in a broad operating temperature range. Good agreement between the experimental results and theoretically calculated calibration plot predicted using Bose-Einstein statistics was obtained.

High-precision focusing of space optical cameras is the prerequisite for capturing high-quality images in earth observation applications. On-orbit focusing methods are basically based on image-processing algorithms. However, these focusing methods have several limitations, such as calculation complexity, low reliability, and high susceptibility to noises. We propose a real-time self-focusing method using conjugated optical fiber waveguides, which can measure the focal length of on-orbit cameras in real time. We use two conjugated optical fiber waveguides. At one end of each waveguide, there is a light source located external to the camera. The light is guided into the focal plane of the camera and it acts as an infinite point target. Contrary to image processing algorithm, our method is based on the optical components for focusing.

Large-scale assembly of individual atoms over smooth surfaces is difficult to achieve. A configuration of an atom reservoir, in which individual atoms can be readily extracted, may successfully address this challenge. In this work, we demonstrate that a liquid gold–silicon alloy established in classical vapor–liquid–solid growth can deposit ordered and three-dimensional rings of isolated gold atoms over silicon nanowire sidewalls. We perform ab initio molecular dynamics simulation and unveil a surprising single atomic gold-catalyzed chemical etching of silicon. Experimental verification of this catalytic process in silicon nanowires yields dopant-dependent, massive and ordered 3D grooves with spacing down to ~5 nm. Finally, we use these grooves as self-labeled and ex situ markers to resolve several complex silicon growths, including the formation of nodes, kinks, scale-like interfaces, and curved backbones., Parallel patterning of atoms over a large surface would represent a major advance over current serial methods of single atom manipulation. Here, the authors explore a periodic instability from liquid alloy droplets for high-throughput atom printing.

The improvement of the time performance of a pattern matching algorithm mainly lies in reducing the number of character comparisons and increasing the distance of text string matching window moving to the right when mismatch occurs. To solve these problems, an improved algorithm based on the combination of word frequency, BNDM and BMHS2 is proposed. Firstly, in order to reduce the number of character comparisons in each matching window, a matching algorithm based on word frequency is introduced; Secondly, in order to improve the moving distance of matching window, BMHS2 and BNDM algorithms are introduced. when mismatch occurs, the matching window is moved to the right by using a large jump distance in BNDM and BMHS2 algorithms. Finally, the time performance of the three algorithms is tested and compared by multiple experiments. Experimental results show that the improved pattern matching algorithm I_BNDM_BMHS2 improves the matching time performance to some extent compared with BNDM and BMHS2 algorithms under the same experimental conditions.

Open-pit mine vehicle scheduling problem is mainly about allocating and designing the schedule of trucks and electric forklift under the constraints, which includes the decision of transportation route, distribution of electric forklifts and trucks number at different mining area with the objective of maximizing equipment utilization rate and reducing production cost. In addition, the various real-time practical changes in mining lead open-pit mine vehicle scheduling problem a dynamic scheduling problem. In this paper, the mathematical model of open-pit mines vehicle scheduling problem using continuous time modeling is established. The transport process, characteristics and requirements of vehicle scheduling problem in open-pit mines are analyzed. For large-scale examples, an approximate dynamic programming model is established by ADP algorithm based on Q-Learning. Numerical experiments of different extraction methods of feature vector and update methods of coefficient vector are carried out, and the results are compared with the results by using solver. The experimental results present that the ADP algorithm designed in this paper can effectively solve the large scale open-pit mine vehicle scheduling problem.