5,265 research outputs found

    Abstraction of Elementary Hybrid Systems by Variable Transformation

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    Elementary hybrid systems (EHSs) are those hybrid systems (HSs) containing elementary functions such as exp, ln, sin, cos, etc. EHSs are very common in practice, especially in safety-critical domains. Due to the non-polynomial expressions which lead to undecidable arithmetic, verification of EHSs is very hard. Existing approaches based on partition of state space or over-approximation of reachable sets suffer from state explosion or inflation of numerical errors. In this paper, we propose a symbolic abstraction approach that reduces EHSs to polynomial hybrid systems (PHSs), by replacing all non-polynomial terms with newly introduced variables. Thus the verification of EHSs is reduced to the one of PHSs, enabling us to apply all the well-established verification techniques and tools for PHSs to EHSs. In this way, it is possible to avoid the limitations of many existing methods. We illustrate the abstraction approach and its application in safety verification of EHSs by several real world examples

    Research on a monitoring terminal for a fibre grating sensing device based on Android

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    AbstractAccording to the actual needs of FBG sensing instruments in terms of intelligent terminals, software for FBG sensing monitoring systems is designed based on the current mainstream Android operating system, which runs on 3G mobile phones. The software is used to remotely access and manage a fibre optic sensing device. The use of the intelligent terminal software will enhance the level of safety monitoring instrument intelligence so that the management of the monitoring system will be more flexible, system maintenance will be more convenient, and the reliability and security of monitoring equipment can also improved; i.e., it provides good value for the optical fibre sensing application

    Fabrication of micro-scale radiation shielding structures using tungsten nanoink through electrohydrodynamic inkjet printing

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    Electronics components used in space and strategic missions are exposed to harsh radiation environments, which could cause operational malfunction of the system through lattice displacement or ionization effects. One potential solution is to use tungsten as radiation shielding. Tungsten is a very effective material in shielding electronic components and manufacturing gratings for x-ray imaging. However, intrinsic properties of tungsten (e.g. density, chemical/thermal inertness and hardness) post a significant challenge of fabricating the material into micro-scale and delicate structures, especially in electronic device fabrication. To address the problem, we designed a new tungsten nanoink and developed a straightforward approach to create tungsten micro-structures by 3D printing. Various microstructures down to 10 µm resolution have been patterned and fabricated by electrohydrodynamic inkjet (e-jet) printing using tungsten nanoink. By optimizing process parameters (voltage modality) and materials properties (ink formulation), the dimension and morphology of the structures can be precisely controlled. An AC-modulated voltage was employed during the e-jet printing process to make the patterns much more controllable and stable. Multi-layer tungsten lines were characterized by x-ray imaging and exhibited excellent absorption of x-ray radiation. With the same thickness, printed lines showed nearly 1/3 absorptivity of x-ray radiation of bulk tungsten, leading to significant radiation attenuation effectiveness. Tungsten nanoink is a new material used in e-jet printing that has not been reported in the literature to the best of authors\u27 knowledge. The study establishes a new methodology of manufacturing micro-nano scale shielding components for electronic devices and rapid prototyping of gratings and collimators in radiography for medical and inspection applications. The research also provides practical guidance to fabricate high melting-point metals via nanoink and micro/nano scale 3D printing

    Genome cloning and genetic evolution analysis of eight duck-sourced novel goose parvovirus strains in China in 2023

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    IntroductionThere are three major categories of waterfowl parvoviruses, namely goose parvovirus (GPV), Muscovy duck parvovirus, and novel goose parvovirus (NGPV). NGPV can infect both Cherry Valley ducks and mule ducks, resulting in short beaks and dwarfism syndrome, and the incidence of short beaks and dwarfism syndrome rises annually, posing a significant threat to the waterfowl breeding and the animal husbandry. Therefore, clarifying the biological characteristics and genetic evolution of NGPV is very important for the prevention and control of NGPV.MethodsDucks with short beaks and dwarfism syndrome from Shandong and Henan Province were investigated by dissection and the tissue samples were collected for study. The NGPV genome was amplified by PCR, and the genome was analyzed for genetic evolution.ResultsEight strains of NGPV were isolated, which were designated as HZ0512, HZ0527, HZ0714, HZ0723, HZ0726, HZ0811, HZ0815, and HN0403. The nucleotide homology among these strains ranged from 99.9% to 100%. The eight strains, along with other NGPVs, belong to GPV. The eight strains showed a 92.5%–98.9% nucleotide homology with the classical GPV, while a 96.0%–99.9% homology with NGPV.Therefore, it can be deduced that there have been no major mutations of NGPV in Shandong and Henan provinces in recent years.DiscussionThis study lays a theoretical foundation for further studying the genetic evolution and pathogenicity of NGPV, thereby facilitating the prevention and control of NGPV

    Application Progress of Oilomics Research in Human Nutrition and Health Research

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    Edible oils and fats are the important dietary nutrients for human body, and play a vital roles in maintaining nutritional health for the hosts. Whereas, the unhealthy oils and fats intake would lead to the increase of the risks of chronic metabolic diseases, which has become a serious public health challenge for the present society. The oilomics, integrating genomics, transcriptomics, proteomics, metabolomics, lipomics as the major analytical methods, have been becoming on important approach to elucidate the host nutritional and metabolic regulation mechanisms, and realize the personalized nutrition of human body based on the functional characteristics of dietary factors. The present review manuscript illustrated the basic concepts of oilomics, and the major research approaches of oilomics in the areas of edible oil nutrition and human health. Moreover, the research progress of oilomics in oil nutrition and host health research were also summarized, primarily, focusing on elaborating the nutrients metabolic regulation, the enteral nutrition and gut homeostasis, as well as the personalized nutrition of the humans. In view of the current research status, the future trends of the development of oilomics were further prospected, at the aim of which is to provide references for expanding the applications of oilomics in lipid nutrition and human health. The overall nutrition level of the nationwide residents will be improved, and the construction of healthy China will be promoted
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