Cation-based resistive switching (RS) devices, dominated by conductive filaments (CF) formation/dissolution, are widely considered for the ultrahigh density nonvolatile memory application. However, the current-retention dilemma that the CF stability deteriorates greatly with decreasing compliance current makes it hard to decrease operating current for memory application and increase driving current for selector application. By centralizing/decentralizing the CF distribution, this current-retention dilemma of cation-based RS devices is broken for the first time. Utilizing the graphene impermeability, the cation injecting path to the RS layer can be well modulated by structure-defective graphene, leading to control of the CF quantity and size. By graphene defect engineering, a low operating current (≈1 µA) memory and a high driving current (≈1 mA) selector are successfully realized in the same material system. Based on systematically materials analysis, the diameter of CF, modulated by graphene defect size, is the major factor for CF stability. Breakthrough in addressing the current-retention dilemma will instruct the future implementation of high-density 3D integration of RS memory immune to crosstalk issues.

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Both Raman spectroscopy and the photoluminescence (PL) spectroscopy are intensively used in studying the characteristics of monolayer MoS2. However, the substrate-related interference effect will influence the optical signal intensities collected from monolayer MoS2. In this work, we investigated the influence of multilayer film interference on the optical signal intensity of monolayer MoS2 on SiO2/Si substrate. Based on our results, the most commonly used substrate for monolayer MoS2, SiO2/Si with SiO2 thickness around 280–300 nm, is not the optimized choice. By considering the interference effect caused by the Air-MoS2-SiO2 multilayers, we can now enhance the optical signal intensity of monolayer MoS2 greatly by selecting proper SiO2 thickness for any chosen incident light wavelength.

The rational structural design of materials is an efficient strategy for optimizing the sensing properties of pressure sensors for electronic skins. Here, inspired by the arches of the foot, a novel Janus graphene film (JGF) with concave‐convex arch‐shaped microstructures on both surfaces is presented. Then, a polymer‐substrate‐free pressure sensor with a wide sensing range, fast response time, and good stability is fabricated using a face‐to‐face assembly method. Its special microstructures can effectively hinder the full contact of two face‐to‐face JGF electrodes and lead to a tunable pressure‐dependent contact area. Subtle pressure variations can be captured due to these special arch‐shaped microstructures. Hence, the JGF‐based pressure sensor could be used to monitor the vital signs of the human body such as human‐body motion, breathing, and arterial pulse. Stable epidermal pulse wave signals are detected, and a series of indices are extracted to assess arterial stiffness and vascular aging. Thanks to its low‐cost, simplified fabrication process, the pressure sensor exhibits great potential for monitoring health in real time and screening for arteriosclerotic disease.

Formation of a banded texture was observed in thin films of a polydiacetylene prepared from the lyotropic nematic phase subject to flow. The banded texture was experimentally investigated by polarizing light microscopy and transmission electron microscopy. The banded structure is initially formed in a nematic phase of the polymer and could be imaged by TEM after its transformation to a lamellar phase which is the polymer analogon to a smectic phase in low-molecular-weight compounds. A mathematical description of the texture is given. During further relaxation of the system in the lyotropic state the initial orientation is lost by the formation of disclinations.

BACKGROUNDAlmonds contain considerable amounts of potential prebiotic components, and the roasting process may alter these components. The aim of this study was to compare the in vitro fermentation properties and in vivo prebiotic effect of raw and roasted almonds.RESULTS In vitro, predigested raw and roasted almonds promoted the growth of Lactobacillus acidophilus (La‐14) and Bifidobacterium breve (JCM 1192), and no significant differences were found between these two nuts. In a 4‐week animal trial, daily intake of raw or roasted almonds promoted the population of Bifidobacterium spp. and Lactobacillus spp. and inhibited the growth of Enterococcus spp. in faeces and caecal contains of rats. Compared with roasted almonds, raw almonds had a greater bifidobacteria promotion effect. Besides, significantly higher β‐galactosidase activity and lower β‐glucuronidase and azoreductase activities in faeces or caecal contents of rats were observed with raw almonds than with roasted almonds. While, in terms of metabolic effects, the ingestion of roasted almonds resulted in significantly greater intestinal lipase activities.CONCLUSIONBoth raw and roasted almonds exhibit potential prebiotic effects, including regulation of intestinal bacteria and improved metabolic activities. The roasting process may slightly reduce the prebiotic effects of almonds but significantly improve the metabolic effects.© 2016 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

An efficient 2 μm in-band pumped Ho:YAG laser was demonstrated. The resonator involves two Ho:YAG crystals, each of which was dual-end-pumped by two orthogonally polarized diode-pumped Tm:YLF lasers. The maximum continuous wave output power of 103 W was achieved, corresponding to a slope efficiency of 67.8% with respect to the incident pump power and an optical-to-optical conversion efficiency of 63.5%. Under Q-switched mode, we obtained 101 W laser output at 30 kHz, corresponding to a slope efficiency of 66.2%. The beam quality or M2 factor was found to be less than 2.

A bulk micromachined relay has been developed with silicon-glass wafer bonding and deep reactive ion etch technologies. The microrelay has a lateral contact structure, and it is laterally driven by electrostatic actuators. The processing is very simple, and only two masks are used. To fulfill different demands, we designed various structures of the microrelay including sizes, contact structures and actuating structures. The mechanical structures are made by single-crystal silicon, which has perfect mechanical performance. Using sputtered gold as contact materials, the measured contact is below 1 .