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A nonlinear dynamic stiffness model of rolling-lobe air spring considering the Payne effect of the rubber diaphragm and the thermodynamic equivalent damping is proposed, with an aim to provide a theoretical basis for air spring structure design. A physical explanation and mathematical expression of each decoupled contribution term are given from the two dimensions of amplitude and frequency. An indicator test was designed to identify related parameters of the real and imaginary parts of dynamic stiffness. The results showed that the dynamic stiffness increases under a small excitation amplitude, verifying the correctness of the model considering the Payne effect. The influence of rubber diaphragm and gas terms is decoupled to separately illustrate the amplitude and frequency dependency of the real and imaginary parts of dynamic stiffness. A new evaluation index reflecting the contribution percentage of the rubber diaphragm is given, indicating that the stiffness of the rubber diaphragm at low amplitude cannot be ignored. In the end, the parameter influence and dynamic characteristics are provided so that the dynamic behavior of the rolling-lobe air spring can be predicted at the design stage. The proposed rolling-lobe air spring dynamic model considering the Payne effect of the rubber diaphragm provides guidance for the forward development and theoretical modeling of the air spring.

Prussian blue analogues (PBAs) have the advantages of stable electrochemical performance and long service life when used as energy storage materials due to their face‒centered cubic structure. Here, Ni‒Co Prussian blue analogue (PBA) nano units have been utilized as precursor to prepare corresponding metal sulfide derivatives, which inherited the structural properties of the precursor. This unique structural exposes more reaction sites and the generation of a small amount of nitrogen-doped carbon that enhances charge transfer. This cube structure has a buffer effect on the stress of the active substance during charging and discharging. The CoS2/Ni3S4‒N‒C provides a capacitance of 817 C g‒1 at 3 A g‒1 and there is still 556 C g‒1 at 20 A g‒1. Furthermore, CoS2/Ni3S4‒N‒C electrode yields outstanding cycle stability (98.2% capacitance retention at 10,000 cycles). An asymmetric supercapacitor (ASC) device consisting of CoS2/ Ni3S4‒N‒C and activated carbon electrodes have an energy density of 40 Wh kg‒1, and a retention rate of 103.7% for 10,000 cycles at 10 A g‒1, presenting excellent cycle stability. The electron properties of Co2NiO4 and CoS2/Ni3S4 − N−C are compared by density functional theory (DFT). CoS2/Ni3S4 − N−C detects more DOS near the Fermi level, leading to larger charge accumulation, indicating that the electron conductivity of the heterojunction is much higher than that of the oxide, and eventually faster reaction kinetics can be obtained.

The on-line tool condition monitoring is demanded to detect the tool wear and to ensure the hole drilling process of printed circuit boards (PCB) goes on smoothly. However, due to the impact of ambient noise caused by the limited size of small drill and the laminated material of PCB, the tool wear signal features are too weak to extract. The stochastic resonance (SR) method has been proven to be effective in enhancing weak signals among various weak signal extraction. In this paper, an adaptive multistable stochastic resonance is presented to improve performance of the SR method and process the tool wear signals for PCB drilling. The differential evolution (DE) algorithm is applied to adaptively optimize potential parameters and compensation factor, which makes the SR method suitable for high frequency signal. Moreover, tool wear experiments with different drill wear are carried out to verify the effectiveness of the proposed method. The results indicate that the proposed method improves the signal-to-noise ratio and has great potential in enhancing weak signals for small drill condition monitoring in PCB drilling process.

Micro-electrochemical machining (micro-ECM) can machine microstructures with excellent surface integrity on difficult-to-cut alloys. During micro-ECM, stray corrosion results in tapered sidewalls of machined structures. To suppress the stray corrosion, a novel tool electrode with the sidewall insulation of a gas film is proposed by fabricating the metal tool sidewall into a hydrophobic surface. The sidewall surface is designed to be characterized with spherical array cavities (radius of 500 nm) acting as the hydrophobic features, enhancing the gas-shielding effect of the gas film under electrolysis. The fabrication process of the hydrophobic sidewall is described in detail, including the self-assembly procedure of a monolayer template of Φ

Long non-coding RNA (lncRNA) is a type of non-coding RNA molecule, which exceeds 200 nucleotides in length and participates in the regulation of a variety of life activities. Recent studies showed that lncRNAs play important roles in viral infection and host immunity. At present, the researches on insect lncRNAs are relatively few. In this study, we found the expression of Lnc_209997 was significantly down-regulated in silkworm fat body infected with Bombyx mori nucleopolyhedrosis virus (BmNPV). Inhibition of Lnc_209997 promoted BmNPV replication. Enhancing the expression of Lnc_209997 inhibited the proliferation of BmNPV. miR-275-5p was up-regulated in silkworm fat body infected with BmNPV. Dual luciferase reporter gene system confirmed the interaction between Lnc_209997 and miR-275-5p. Over-expression of Lnc_209997 inhibited the expression of miR-275-5p, while inhibition of Lnc_209997 enhanced the expression of miR-275-5p. Further, over-expression of miR-275-5p can facilitate the replication of BmNPV. These results suggested that BmNPV could increase the expression of miR-275-5p by inhibiting cellular Lnc_209997 expression to promote their own proliferation. Our results are helpful for better understanding the role of lncRNAs in BmNPV infection, and provide insights into elucidating the molecular mechanism of interaction between Bombyx mori and virus.

Phenotypic plasticity is a heritable trait that provides sessile organisms a strategy to rapidly mitigate negative effects of environmental change. Yet, we have little understanding of the mode of inheritance and genetic architecture of plasticity in different focal traits relevant to agricultural applications. This study builds on our recent discovery of genes controlling temperature-mediated flower size plasticity in Arabidopsis thaliana and focuses on dissecting the mode of inheritance and combining ability of plasticity in the context of plant breeding. We created a full diallel cross using 12 A. thaliana accessions displaying different temperature-mediated flower size plasticities, scored as the fold change between two temperatures. Griffing’s analysis of variance in flower size plasticity indicated that non-additive genetic action shapes this trait and pointed at challenges and opportunities when breeding for reduced plasticity. Our findings provide an outlook of flower size plasticity that is important for developing resilient crops for future climates.

The low capacitance utilization and capacitance fading of manganese dioxide (MnO2) is mainly due to poor electro-conductivity and irreversible phase transform. This work proposes a new method of designing hierarchical and binder-free electrode based on MnO2 material for stable supercapacitor with high specific capacitance. Herein, we fabricated the self-standing electrode of MnO2 on nitrogen-doped graphene and single wall carbon nanotubes (SWCNTs) self-standing film (NGCF) by electrochemical deposition. As a result, as-prepared MnO2/NGCF cathode showed excellent electrochemical performance of 489.7 F g-1 at 1 A g-1. Assembled symmetric aqueous supercapacitor (SC) manifests high voltage of 2.4 V and presents excellent high energy density of 106.7 Wh kg-1 at 1200 W kg-1 and outstanding long-life stability without no decay after 10 000 charge-discharge circuits. This work proposes a new view of designing hierarchical and binder-free electrode with high energy density and long cycling stability based on MnO2 material for stable symmetric supercapacitor.

Spark-assisted chemical engraving (SACE) is suitable to machine hard and brittle insulating materials such as quartz glass; however, the processing efficiency is quite low for achieving good machin...

In this work, the time-delay effect on device operation caused by capacitance is studied in terms of phase-change memory (PCM) integrated with an ovonic threshold switch (OTS) selector. The capacitance studied in this work is the intrinsic capacitance associated with capacitive reactance of the PCM itself. The capacitance of the PCM in the amorphous state was measured, and it presents an exponential dependence on voltage bias. Through the simulation model of an OTS-PCM integrated device that considering the measured capacitance behavior, the time-delay characteristics of the integrated device for the SET process with various pulses were investigated. Results indicate that the onset of the threshold switching (TS) is delayed in the PCM but occurs early in the OTS with capacitance in the integrated device. In addition, it is found that the variable capacitance behavior can not only minimize the delay effect, but also accelerate the SET operation under certain conditions in the integrated device. Our results can provide practical guidance for the design of fast operating devices.

Adopting the sidewall-insulated hollow electrode (SIHE) is an ideal approach to achieve electrolyte-refresh and stray corrosion inhibition functions in micro electrochemical machining (ECM) processes. Most of the traditional SIHEs are made of metal substrate and non-metal thin films. The insulating film has poor durability, and the preparation approach of the traditional SIHE is complex and has limited repeatability. This research presents a novel structure of a SIHE with an insulated substrate and an internal conductive film. The machining performance of the novel SIHE is primarily verified by a potential distribution analysis in the numerical simulation. According to the concept of the novel SIHE, a silver-plated glass tube electrode (SPGTE) is presented: the glass tube acts as the insulated substrate, and the plated silver layer acts as the working cathode. Then, a fabrication process for the SPGTE is proposed. Silver layers are tightly bonded on the glass tube surface by electroless plating. The thickness of the silver layer is approximately 3.5 μm, and its electrical resistivity is approximately 5 × 10−5 Ω cm. In micro ECM experiments, microstructures with steep sidewalls with taper angles of

The study is designed to improve the efficiency of Internet of Things (IoT) structure detection and achieve the smooth operation of IoT networks. First, the connection between the IoT network structure and maxdegree is investigated based on analyzing the IoT supertask network structure to find the main influence factor of maxdegree, along with the conditions for obtaining the optimal maxdegree. Second, a structural algorithm model of optimal supertask network is proposed as the foundation for achieving the minimum maxdegree. Finally, the human behavior recognition database is taken as the research object to verify its performance through the specific instance data. The IoT network structure factors are proved to include the task quantity, resource capacity, number of networks, and Communication Calculation Ratio (CCR). The experimental results also show that the principal factor that affects maxdegree is the number of different tasks. Besides, there is a mutually positive interaction between the network structure and the IoT maxdegree, which complement each other and form the core network of IoT. Moreover, the results reflect the good performance on different datasets of the supertask IoT network structure for the human behavior recognition database. There exists the optimal maxdegree of the model under the condition of 40 tasks, 32 resources, 6 networks and CCR of 6. Furthermore, the proposed algorithm has a shorter length and lower complexity than other related algorithms, which is very suitable for the construction of IoT networks. The research results can provide some references and practical value for the construction and data processing of the IoT structure.

Polymer nanocomposite coatings have attracted great interest in the anticorrosion fields due to their excellent properties. Nanofillers are necessary to achieve high anticorrosion performance of the polymer coating. Herein, we report a wet-chemical template strategy to prepare large-size ZrO2 nanosheets, in which the Zr4+ ions are anchored on the surface of a graphene oxide template via electrostatic adsorption, followed by a thermal treatment process to remove graphene. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images show that the size and thickness of as-prepared ZrO2 nanosheets are more than 2 μm and ~ 4.5 nm, respectively. The micron-scale ultrathin two-dimension (2D) ZrO2 nanosheets, for the first time, are utilized as the anticorrosive fillers in the epoxy coating to reduce the porosity, consequently promoting the gas and water barrier properties of the composite coating. The polymer coating containing 1.0 wt% ZrO2 nanosheets shows a high initial impedance (89.1 GΩ·cm2) that can protect the metal substrate from being corroded during long-term immersion (60 days), which is better than that of the reduced graphene oxide (rGO)-incorporated coating and the ZrO2 nanoparticles-incorporated coating. This work offers valuable insights into the design and preparation of novel and efficient 2D electric-inert nanofillers for anticorrosion coatings.

In micro electrical discharge machining (micro EDM) using the non-hollow circular cross-section tool electrode with the side flushing technique, when the aspect ratio of machined micro-hole is expected to be further increased, the discharge debris expelling speed and the working fluid renewal efficiency are weakened, which hinders the improvement of machining efficiency and accuracy with increased machining depth. In order to reveal the flow behavior of the working fluid in the micro EDM gap, so as to realize the high-precision and high-efficiency machining of micro-hole with high aspect ratio, a three-phase flow simulation model of fluid, bubble and debris is established in Fluent under the ideal assumption that the spark discharges occur continuously to generate high-pressure bubbles. The simulation results show that when the boundary condition of the flushing pressure at the side gap entrance is set to 0, the pressure wave emitted when the high-pressure bubble expands, which is formed by the instantaneous gasification of the working fluid between electrodes under high temperature, is the source of pneumatic force that drives the working fluid flow at the micron scale. Affected by the gap flow channel structure and the viscous resistance from inner wall, the flow velocity direction of the fluid dragging the discharge debris to rise up and expel will change, forming a dynamic alternation process of flowing into and out of the side machining gap entry. As the machining depth increases, due to the energy attenuation of the pressure wave propagating from the bottom gap to the side gap entrance, the expelling speed of the discharge debris decreases exponentially at the side gap entrance, resulting in the reduced machining efficiency and accuracy. However, when the simulated bubble generation frequency is increased to the MHz level, the expelling efficiency of debris has a step-like improvement. The continuous and high-frequency generation of high-pressure bubbles can maintain a high pressure gradient in the bottom gap, and the discharge debris is able to continuously move upward without falling back to accumulate in the bottom gap, which is beneficial to the stable and smooth machining process, realizing the high-precision and high-efficiency machining of micro-hole with high aspect ratio.

Aqueous Zn (zinc) metal batteries have gotten a lot of interest and research because of their great volumetric capacity, low production cost, and high use safety. However, the coulombic efficiency of the Zn metal anode is low due to Zn dendrites formed during the charging and discharging processes of the battery, and the corrosion problem of the Zn anode in the electrolyte also reduces the battery's cycling stability and hinders its practical application. In this paper, InF