64 research outputs found

    Dynamic Nondestructive Detection Models of Apple Quality in Critical Harvest Period Based on Near-Infrared Spectroscopy and Intelligent Algorithms

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    Apples are usually bagged during the growing process, which can effectively improve the quality. Establishing an in situ nondestructive testing model for in-tree apples is very important for fruit companies in selecting raw apple materials for valuation. Low-maturity apples and high-maturity apples were acquired separately by a handheld tester for the internal quality assessment of apples developed by our group, and the effects of the two maturity levels on the soluble solids content (SSC) detection of apples were compared. Four feature selection algorithms, like ant colony optimization (ACO), were used to reduce the spectral complexity and improve the apple SSC detection accuracy. The comparison showed that the diffuse reflectance spectra of high-maturity apples better reflected the internal SSC information of the apples. The diffuse reflectance spectra of the high-maturity apples combined with the ACO algorithm achieved the best results for SSC prediction, with a prediction correlation coefficient (Rp) of 0.88, a root mean square error of prediction (RMSEP) of 0.5678 °Brix, and a residual prediction deviation (RPD) value of 2.466. Additionally, the fruit maturity was predicted using PLS-LDA based on color data, achieveing accuracies of 99.03% and 99.35% for low- and high-maturity fruits, respectively. These results suggest that in-tree apple in situ detection has great potential to enable improved robustness and accuracy in modeling apple quality

    Search for Wγ resonances in proton-proton collisions at s=13 TeV using hadronic decays of Lorentz-boosted W bosons

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    A search for Wγ resonances in the mass range between 0.7 and 6.0 TeV is presented. The W boson is reconstructed via its hadronic decays, with the final-state products forming a single large-radius jet, owing to a high Lorentz boost of the W boson. The search is based on proton-proton collision data at s=13 TeV, corresponding to an integrated luminosity of 137 fb−1, collected with the CMS detector at the LHC in 2016–2018. The Wγ mass spectrum is parameterized with a smoothly falling background function and examined for the presence of resonance-like signals. No significant excess above the predicted background is observed. Model-specific upper limits at 95% confidence level on the product of the cross section and branching fraction to the Wγ channel are set. Limits for narrow resonances and for resonances with an intrinsic width equal to 5% of their mass, for spin-0 and spin-1 hypotheses, range between 0.17 fb at 6.0 TeV and 55 fb at 0.7 TeV. These are the most restrictive limits to date on the existence of such resonances over a large range of probed masses. In specific heavy scalar (vector) triplet benchmark models, narrow resonances with masses between 0.75 (1.15) and 1.40 (1.36) TeV are excluded for a range of model parameters. Model-independent limits on the product of the cross section, signal acceptance, and branching fraction to the Wγ channel are set for minimum Wγ mass thresholds between 1.5 and 8.0 TeV

    Search for CP violating top quark couplings in pp collisions at √s = 13 TeV

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    Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb(-1). The search uses two observables, O-1 and O-3, which are Lorentz scalars. The observable O-1 is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while O-3 consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model

    Observation of triple J/ψ meson production in proton-proton collisions

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    Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering - referred to as single-parton scattering - leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/psi mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process - reconstructed through the decays of J/psi mesons into pairs of oppositely charged muons - with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be 272(-104)(+141) (stat) +/- 17 (syst) fb, and compared it to theoretical expectations for triple-J/psi meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process

    CMS pythia 8 colour reconnection tunes based on underlying-event data

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    New sets of parameter tunes for two of the colour reconnection models, quantum chromodynamics-inspired and gluon-move, implemented in the pythia 8 event generator, are obtained based on the default CMS pythia 8 underlying-event tune, CP5. Measurements sensitive to the underlying event performed by the CMS experiment at centre-of-mass energies s=7 and 13 TeV , and by the CDF experiment at 1.96 TeV are used to constrain the parameters of colour reconnection models and multiple-parton interactions simultaneously. The new colour reconnection tunes are compared with various measurements at 1.96, 7, 8, and 13 TeV including measurements of the underlying-event, strange-particle multiplicities, jet substructure observables, jet shapes, and colour flow in top quark pair (t t ̄) events. The new tunes are also used to estimate the uncertainty related to colour reconnection modelling in the top quark mass measurement using the decay products of t t ̄ events in the semileptonic channel at 13 TeV . © 2023, The Author(s)

    Search for Wγ resonances in proton-proton collisions at s=13 TeV using hadronic decays of Lorentz-boosted W bosons

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    Copyright © The Author(s). A search for resonances in the mass range between 0.7 and 6.0 TeV is presented. The W boson is reconstructed via its hadronic decays, with the final-state products forming a single large-radius jet, owing to a high Lorentz boost of the W boson. The search is based on proton-proton collision data at TeV, corresponding to an integrated luminosity of 137 fb−1, collected with the CMS detector at the LHC in 2016–2018. The mass spectrum is parameterized with a smoothly falling background function and examined for the presence of resonance-like signals. No significant excess above the predicted background is observed. Model-specific upper limits at 95% confidence level on the product of the cross section and branching fraction to the channel are set. Limits for narrow resonances and for resonances with an intrinsic width equal to 5% of their mass, for spin-0 and spin-1 hypotheses, range between 0.17 fb at 6.0 TeV and 55 fb at 0.7 TeV. These are the most restrictive limits to date on the existence of such resonances over a large range of probed masses. In specific heavy scalar (vector) triplet benchmark models, narrow resonances with masses between 0.75 (1.15) and 1.40 (1.36) TeV are excluded for a range of model parameters. Model-independent limits on the product of the cross section, signal acceptance, and branching fraction to the channel are set for minimum mass thresholds between 1.5 and 8.0 TeV.SCOAP3

    Development of multifunctional metal-organic frameworks (MOFs)-based nanofiller materials in food packaging: A comprehensive review

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    Background: Food packaging effectively reduces food postharvest losses, ensures food safety supply, and promotes sustainable development. Metal-organic frameworks (MOFs)-based film materials showed potential in the field of food packaging. Among various nanofillers, MOFs stand out as multifunctional materials characterized by their convenient integration with polymer matrix to develop enhanced, active and intelligent food packaging materials. Scope and approach: This review initially provided a concise overview of the several synthesis strategies of MOFs and three primary methods for the fabrication of MOFs-based films. Furthermore, the multifaceted functions of MOFs as reinforcers, active agents, and indicative factors in the context of food packaging have also been systematically reviewed. Especially, the functional MOFs-based films for the encapsulation of diverse bioactive compounds applied to delay food spoilage and real-time monitoring of food freshness were discussed. Finally, the toxicological impacts of MOF fillers in food packaging applications were highlighted, encompassing an evaluation of potential risks and the exploration of mitigation strategies. Key findings and conclusions: The MOFs-based films emerge as promising candidate materials for food packaging applications, as the incorporation of MOFs substantially enhances the mechanical properties, water resistance, and barrier performance of pure biopolymer films. However, traditional food packaging methodologies encounter several challenges, including antibacterial, antioxidant properties, and the effective removal of active molecules. To overcome these limitations, the incorporation of various MOF nanomaterials to enhance the physical and functional attributes of packaging films have been persistently investigated. Therefore, MOFs-based multifunctional film materials could be a viable alternative to develop food packaging

    The Methods for Reducing the Number of OOVs in Chinese-Uyghur NMT System

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    Pair distribution function analysis for oxide defect identification through feature extraction and supervised learning

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    Feature extraction and a neural network model are applied to predict defect types and concentrations in experimental anatase TiO2 samples. A dataset of TiO2 structures with vacancies and interstitials of oxygen and titanium is built, and the structures are relaxed using energy minimization. The features of the calculated pair distribution functions (PDFs) of these defected structures are extracted using linear methods (principal component analysis and non-negative matrix factorization) and non-linear methods (autoencoder and convolutional neural network). The extracted features are used as inputs to a neural network that maps feature weights to the concentration of each defect type. The performance of this machine learning pipeline is validated by predicting defect concentrations based on experimentally measured TiO2 PDFs and comparing the results to brute-force predictions. A physics-based initialization of the autoencoder has the highest accuracy in predicting defect concentrations. This model incorporates physical interpretability and predictability of material structures, enabling a more efficient characterization process with scattering data

    Flexible label-free SERS substrate with alginate-chitosan@silver nanocube for in situ nondestructive detection of thiram on apples

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    The rapid in situ detection of pesticide residues in real samples based on surface-enhanced Raman spectroscopy (SERS) remains a challenge, necessitating an urgent need for a feasible solution that addresses issues such as sample complexity, reproducibility, and SERS substrate stability. This paper proposes a flexible SERS substrate, which consists of a composite gel made of sodium alginate-chitosan loaded with silver nanocubes (SA-CTS@AgNCs). The flexible nature of the SERS substrate enables the analysis of irregular surfaces of apples, dispensing with laborious pretreatment and promoting an effective contact with target molecules. By utilizing the SA-CTS@AgNCs substrate in conjunction with a portable Raman instrument, an exceptional sensitivity was achieved with a detection limit of 0.055 mg/L for thiram in apples. In addition, the stability, homogeneity, and batch-to-batch reproducibility of the substrates were evaluated. The experimental results showed that after 45 days of storage, the substrate still maintained more than 84.40 % SERS activity, demonstrating long-term stability. Within a single substrate, the point-to-point relative standard deviation (RSD) was only 4.2 %, while among different batches of substrates, the RSD was as low as 6.8 %, displaying better homogeneity and reproducibility. Hence, this flexible SERS substrate provides a reliable and convenient platform for rapid detection and on-site monitoring of food safety
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