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Synthesis and spectroscopic investigations of trivalent europium- doped Z_(2)Si_(3)O_(8)(Z = Mg, Ca and Sr) nanophosphors for display applications

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Rare Metals 2021年第9期40卷 2610-2617页

作者： Suman Sheoran Kuldeep Singh vijeta tanwar Sitender Singh Anura Samantilleke Devender Singh Department of Chemistry Maharshi Dayanand UniversityRohtak 124001India Centro de Fisica Universidade of MinhoBraga 4710057Portugal

To explore the silicate lattice-based nanophosphors, a series of Eu3+-doped Z_(2)Si_(3)O_(8)(Z = Mg, Ca and Sr) materials were prepared by sol–gel procedure. The metal nitrates and silica powder were used as precursor components for the synthesis of these luminescent materials. Photoluminescence(PL) emission spectra, powder X-ray diffraction(PXRD), energy-dispersive X-ray spectroscopy(EDS), Fourier transform infrared spectroscopy(FTIR) and transmission electron microscopy(TEM)spectroscopic techniques were applied for the characterization of the fabricated materials. Three peaks were observed at 589, 613 and 650–652 nm corresponding to ^(5)D_(0)→^(7)F_(1-3) transition in PL emission spectra. Upon395 nm excitation and at 0.03 mol Eu3+, these nanophosphors displayed optimum photoluminescence with the most intense peak analogous to ^(5)D_(0)→^(7)F_(2)transition of dopant ion. The as-prepared phosphor materials were re-heated at1050 and 1150 ℃ to observe the consequences of higher temperatures on the emission intensity and crystal *** analysis confirmed that all the synthesized materials were of crystalline nature, and the crystallinity was observed to be improved by increasing the temperature. In the FTIR spectrum, peaks at 483 and 610 cm^(-1) proved the existence of SiO_(4)group in Ca_(2)Si_(3)O_(8), and the peak centered at 417 cm^(-1) confirmed the presence of MgO6 octahedral in Mg_(2)Si_(3)O_(8) materials. TEM images were used to determine the particle size(13–35 nm) and to study the threedimensional structure of nanophosphor materials. The experimental studies indicate that these materials may be promising as red-emitting nanophosphors for white lightemitting diodes.

关键词： Z_(2)Si_(3)O_(8) Nanophosphors Sol–gel Photoluminescence Crystalline

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Multi-gradient-direction based deep learning model for arecanut disease identification

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CAAI Transactions on Intelligence Technology 2022年第2期7卷 156-166页

作者： S.B.Mallikarjuna Palaiahnakote Shivakumara vijeta Khare M.Basavanna Umapada Pal B.Poornima Department of Computer Science and Engineering Bapuji Institute of Engineering and TechnologyDavanagereAffiliated to Visvesvaraya Theological UniversityBelagaviKarnatakaIndia Faculty of Computer Science and Information Technology University of MalayaKuala LumpurMalaysia Adani Institute of Infrastructure Engineering AhmedabadIndia Department of Computer Science Davanagere UniversityDavanagereKarnatakaIndia Computer Vision and Pattern Recognition Unit Indian Statistical InstituteKolkataWest BengalIndia

Arecanut disease identification is a challenging problem in the field of image *** this work,we present a new combination of multi-gradient-direction and deep con-volutional neural networks for arecanut disease identification,namely,rot,split and *** to the effect of the disease,there are chances of losing vital details in the *** enhance the fine details in the images affected by diseases,we explore multi-Sobel directional masks for convolving with the input image,which results in enhanced *** proposed method extracts arecanut as foreground from the enhanced images using Otsu ***,the features are extracted for foreground information for disease identification by exploring the ResNet *** advantage of the proposed approach is that it identifies the diseased images from the healthy arecanut *** results on the dataset of four classes(healthy,rot,split and rot-split)show that the proposed model is superior in terms of classification rate.

关键词： deep learning image analysis pattern recognition

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Prophylactic effects of asiaticoside-based standardized extract of Centella asiatica(L.) Urban leaves on experimental migraine: Involvement of 5HT1A/1B receptors

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Chinese Journal of Natural Medicines 2015年第4期13卷 274-282页

作者： vijeta Bobade Subhash L.Bodhankar Urmila Aswar Vishwaraman Mohan Prasad Thakurdesai Department of Pharmacology Poona College of Pharmacy Bharati Vidyapeeth Deemed University Department of Pharmacology Sinhgad Institute of Pharmacy Indus Biotech Private Limited 1 Rahul residency Kondhwa Pune-411026 India

The present study aimed at evaluation of prophylactic efficacy and possible mechanisms of asiaticoside （AS） based standardized extract of Centella asiatica （L.） Urban leaves （INDCA） in animal models of migraine. The effects of oral and intranasal （i.n.） pretreatment of INDCA （acute and 7-days subacute） were evaluated against nitroglycerine （NTG, 10 mg·kg^-1, i.p.） and bradykinin （BK, 10 μg, intra-arterial） induced hyperalgesia in rats. Tail flick latencies （from 0 to 240 rain） post-NTG treatment and the number of vocalizations post-BK treatment were recorded as a measure of hyperalgesia. Separate groups of rats for negative （Normal） and positive （sumatriptan, 42 *** ^-1, s.c.） controls were included. The interaction of 1NDCA with selective 5-HT1A, 5-HT1B, and 5-HTI D receptor antagonists （NAN-190, Isamoltane hemifumarate, and BRL-15572 respectively） against NTG-induced hyperalgesia was also evaluated. Acute and sub-acute pre-treatment of INDCA [10 and 30 ***^-1 （oral） and 100 μg/rat （i.n.） showed significant anti-nociception activity, and reversal of the NTG-induced hypera｜gesia and brain 5-HT concentration decline. Oral pre-treatment with INDCA （30 mg·kg ^-1, 7 d） showed significant reduction in the number of vocalization. The anti-nociceptive effects of INDCA were blocked by 5-HTIA and 5-HT1B but not 5-HT1D receptor antagonists. In conclusion, 1NDCA demonstrated promising anti-nociceptive effects in animal models of migraine, probably through 5-HT1A/1B medicated action.

关键词： Centella asiatica (L.) Urban Experimental migraine Anti-nociception Serotonin, 5HTI A and 5HT1B receptors

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