34 research outputs found

    Secure Teleoperation Control Using Somewhat Homomorphic Encryption

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    Presented at 2022 Modeling, Estimation, and Control Conference (MECC) , October 2022The goal of this research is to establish control theoretic methods to enhance cyber security of networked motion control systems by utilizing somewhat homomorphic encryption. The proposed approach will encrypt the entire motion control schemes including: sensor signals, model parameters, feedback gains, and performs computation in the ciphertext space to generate motion commands to servo systems without a security hole. The paper will discuss implementation of encrypted bilateral teleoperation control schemes with nonlinear friction compensation. The paper will present (1) encrypted teleoperation control realization with somewhat homomorphic encryption and (2) simulation results.This work was supported in part by the National Science Foundation under Grant No. 2112793 and the Japan Society for the Promotion of Science KAKENHI Grant No. JP22H01509

    BLOOM: A 176B-Parameter Open-Access Multilingual Language Model

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    Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License

    Experimental Study on Residual Bending Strength of Corroded Reinforced Concrete Beam Based on Micromagnetic Sensor

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    This paper presents a nondestructive test method to evaluate the residual bending strength of corroded reinforced concrete beam by analyzing the self-magnetic flux leakage (SMFL) signals. The automatic scanning device was equipped with a micromagnetic sensor and sensor-based experimental details were introduced. Next, the theoretical formula of the normal component HS(z) of the SMFL signal that originated from the corroded region was derived based on the magnetic dipole model and the experimental results were discussed. The results indicate that the experimental data of HS(z) are consistent with the theoretical calculations, both location and extent of the steel bars corrosion can be qualitatively determined by using HS(z). The gradient K of HS(z) is approximately linearly related to the loss rate, S, of the bending strength, which can be used to evaluate the residual bending strength of the corroded reinforced concrete beam. This work lays the foundation for evaluating the residual bending strength of corroded reinforced concrete beams using the SMFL signal; the micromagnetic sensor is further applied to the civil engineering

    Light-induced reversible expansion of individual gold nanoplates

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    Light-induced mechanical response of materials has been extensively investigated and widely utilized to convert light energy into mechanical energy directly. The metallic nanomaterials have excellent photothermal properties and show enormous potential in micromechanical actuators, etc. However, the photo-thermo-mechanical properties of individual metallic nanostructures have yet to be well investigated. Here, we experimentally demonstrate a way to realize light-induced reversible expansion of individual gold nanoplates on optical microfibers. The light-induced thermal expansion coefficient is obtained as 21.4 ± 4.6 ∌ 31.5 ± 4.2 Ό·K-1 when the light-induced heating temperature of the gold nanoplates is 240 ∌ 490 °C. The photo-thermo-mechanical response time of the gold nanoplates is about 0.3 ± 0.1 s. This insight into the photo-thermo-mechanical properties of the gold nanoplates could deepen the understanding of the light-induced reversible expansion behavior in nanoscale and pave the way for applications based on this piezoelectric-like response, such as light-driven metallic micromotors

    Electrospinning of ZIF-67 Derived Co-C-N Composite Efficiently Activating Peroxymonosulfate to Degrade Dimethyl Phthalate

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    In this work, an efficient cage-core peroxymonosulfate (PMS) catalyst was synthesized by applying an electrospinning–calcination process to the cobalt–zeolitic imidazole framework (ZIF-67) crystals for the catalytic degradation of dimethyl phthalate (DMP). The morphology and surface properties of the synthesized materials (ZIF-67, Z600 and ZP400/600/800) were well characterized. ZP600 showed great performance for the catalytic degradation of DMP in the initial pH range of 7.5–10.5. The removal rate of DMP could reach 90.4% in 60 min under optimum dosages of reagents (catalyst = 0.1 g/L, PMS = 0.5 mM, DMP = 6 ppm), and the mineralization degree of contaminant could reach 65%. By quenching experiments, it was determined that sulfate radical (SO4−·) and hydroxyl radical (·OH) dominated the degradation process. Moreover, due to the good magnetism, ZP600 could be easily separated from liquid and showed great reusability in five-cycle reaction experiments. Surprisingly, with the cover of cage-like polyacrylonitrile (PAN) fibers, the cobalt leaching amount of ZP600 decreased by about 87%. This study would expand the application of the electrospinning process in the development of functional materials for water purification

    Electrospinning of ZIF-67 Derived Co-C-N Composite Efficiently Activating Peroxymonosulfate to Degrade Dimethyl Phthalate

    No full text
    In this work, an efficient cage-core peroxymonosulfate (PMS) catalyst was synthesized by applying an electrospinning–calcination process to the cobalt–zeolitic imidazole framework (ZIF-67) crystals for the catalytic degradation of dimethyl phthalate (DMP). The morphology and surface properties of the synthesized materials (ZIF-67, Z600 and ZP400/600/800) were well characterized. ZP600 showed great performance for the catalytic degradation of DMP in the initial pH range of 7.5–10.5. The removal rate of DMP could reach 90.4% in 60 min under optimum dosages of reagents (catalyst = 0.1 g/L, PMS = 0.5 mM, DMP = 6 ppm), and the mineralization degree of contaminant could reach 65%. By quenching experiments, it was determined that sulfate radical (SO4−·) and hydroxyl radical (·OH) dominated the degradation process. Moreover, due to the good magnetism, ZP600 could be easily separated from liquid and showed great reusability in five-cycle reaction experiments. Surprisingly, with the cover of cage-like polyacrylonitrile (PAN) fibers, the cobalt leaching amount of ZP600 decreased by about 87%. This study would expand the application of the electrospinning process in the development of functional materials for water purification

    Self-depleted T-gate Schottky barrier tunneling FET with low average subthreshold slope and high I<inf>ON</inf>/I<inf>OFF</inf> by gate configuration and barrier modulation

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    In this paper, a novel silicon-based T-gate Schottky barrier tunneling FET (TSB-TFET) is proposed and experimentally demonstrated. With enhanced electric field at source side through gate configuration for steeper subthreshold slope (SS), the device with self-depleted structure can effectively suppress the leakage current and simultaneously achieve the dominant Schottky barrier tunneling current for high ON-current without area penalty, which can alleviate the problems in silicon TFET. In addition, the proposed TSB-TFET can have comparable DIBL effect and reduced gate-to-drain capacitance compared with traditional TFET. Further device optimization is experimentally achieved by extended multi-finger gate configuration of the same footprint and barrier modulation by dopant segregation Schottky technology. With compatible bulk CMOS technology, the fabricated device can achieve steep SS over almost 5 decades of current, as well as high ION/IOFF ratio (??10 7). The proposed device with high compatibility is very promising for future low power system applications. ? 2011 IEEE.EI

    Artificial photosynthesis bringing new vigor into plastic wastes

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    Abstract The accumulation of plastic wastes in landfills and the environment threatens our environment and public health, while leading to the loss of potential carbon resources. The urgent necessary lies in developing an energy‐saving and environmentally benign approach to upgrade plastic into value‐added chemicals. Artificial photosynthesis holds the ability to realize plastic upcycling by using endless solar energy under mild conditions, but remains in the initial stage for plastic upgrading. In this review, we aim to look critically at the photocatalytic conversion of plastic wastes from the perspective of resource reutilization. To begin with, we present the emerging conversion routes for plastic wastes and highlight the advantages of artificial photosynthesis for processing plastic wastes. By parsing photocatalytic plastic conversion process, we demonstrate the currently available routes for processing plastic, including plastic photodegradation, tandem decomposition of plastic and CO2 reduction, selective plastic oxidation, as well as photoreforming of plastic. This review concludes with a personal perspective for potential advances and emerging challenges in photocatalytic plastic conversion

    Formation of Uniform Colloidal Spheres Based on Lignosulfonate, a Renewable Biomass Resource Recovered from Pulping Spent Liquor

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    Effects of mass ratios on the sodium lignosulfoante (NaLS) and cetyltrimethylammonium bromide (CTAB) mixing system were first investigated by zeta potential and surface tension measurements. Uniform colloidal spheres from the NaLS/CTAB complex were then fabricated via electrostatic and hydrophobic self-assembly and characterized by DLS, TEM, contact angle, elemental analysis, XPS, and FTIR measurements. Results showed the stoichiometric mass ratio (SMR) of the NaLS/CTAB system was 1:2.82, where the hydrophobicity was strongest and preparing colloidal spheres was feasible. Colloidal spheres were formed through gradual aggregation of NaLS/CTAB molecules at SMR, which was induced by continuously adding water into NaLS/CTAB/EtOH solutions. NaLS/CTAB molecules started to form spheres at a critical water content of 58 vol %, and the formation process was completed at a water content of 84 vol % when the initial concentration of NaLS/CTAB in EtOH was 1.0 mg mL<sup>–1</sup>. The sizes of NaLS/CTAB colloidal spheres could be well controlled by adjusting water-adding rates. This preparation of lignosulfonate-based nanoparticles is very simple, safe, and low-cost, and these obtained nanoparticles have advantages of biodegradability and ultraviolet resistance. This study provides a green and valuable approach to value-added applications of lignosulfonate biomass recovered from pulping spent liquor and is of great significance for both economic and environmental benefits

    Computational Design of Porous Organic Frameworks for High-Capacity Hydrogen Storage by Incorporating Lithium Tetrazolide Moieties

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    We propose to incorporate a lithium tetrazolide group into porous materials for enhancing hydrogen storage capacity. The lithium tetrazolide group is much more stable and polarized than the models made by doping aromatic groups with lithium atoms. More importantly, each of the lithium tetrazolide provides 14 binding sites for hydrogen molecules with modest interaction energies. The advantage of multiple binding sites with modest binding energies is partially demonstrated by constructing a new porous aromatics framework (PAF-4) with the lithium tetrazolide moieties and predicting its hydrogen uptake using first-principles GCMC simulations. The predicted hydrogen uptake reaches 4.9 wt % at 233 K and 10 MPa, which exceeds the 2010 DOE target of 4.5 wt %
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