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Progress in Natural Science:Materials International 2019年第4期29卷 457-465页

作者： Suman Sheoran Vachan singh Sitender singh Sonika Kadyan Jasbir singh Devender singh Department of Chemistry Maharshi Dayanand University Department of Physics Government College

Down-conversion properties of Eu3+doped M2Y2Si2O9(M=ba,Ca,Mg,Sr) phosphors have been investigated in *** phosphors were synthesized via the simple,fast and cost-effective sol-gel technique at a temperature of 950℃.Color coordinates and emission color can be altered by the varying concentration of dopant ion in *** luminescence intensity was obtained when doping 0.03 mol of Eu3+*** the excitation wavelength of 395 nm,these silicates showed strong red color,pure and sharp spectral peaks in visible region due to ~5 D0→F1-3transitions of Eu3+present in the *** of reaction temperature on luminescence was also analyzed for these *** sharp peaks in the X-ray diffraction pattern indicated the high crystallinity of prepared ***2Y2Si2O9has shown an orthorhombic crystal *** FtIR results confirmed the metal-oxygen vibrational modes available in the range of 400-1600 *** electron microscopy images have revealed that the variation of alkaline earth metal provided a very different crystal *** down conversion response of these phosphor materials can provide a great significance in the application of the coming solar devices.

关键词： M2Y2Si2O9:Eu3+ Phosphor Sol-gel Lattice Solar devices

Zr, Hf, U, th and REE-Fertile Lower Proterozoic Potassic Granite from Parts of Andhra Pradesh, South India

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Acta Geologica Sinica(English Edition) 2004年第4期78卷 921-930页

作者： Yamuna singh Atomic Minerals Directorate for Exploration and Research

the medium- to coarse-grained and porphyritic granitoid of Dharmawaram, Karimnagar district, Andhra Pradesh, south India is a biotite-hornblende granite with notable contents of rare metal (Zr, Hf, th) and rare earth (including Y) minerals like zircon, thorite, allanite, monazite and xenotime. Chemically, it is metaluminous (average A/ C+N+K = 0.95)-type, potassic (av. 5% K2O) granite, with dominantly sub-alkaline characters. It shows up to 8 times enrichment of rare metals (Zr, Hf, U, th) and rare earths (including Y, Sc), with reference to their abundances in normal unevolved granite, and hence, fertile for some of these elements. Field, petrological, geochemical and isotopic data of potassic granite (PG) indicate involvement of silica-rich metasedimentary-basic crustal rocks (amphibole-quartzite, amphibolite, hornblende-biotite gneiss, etc.) in its genesis, at a depth range of 30 km. Further, chondrite-normalized REE patterns demonstrate that low-degree partial melting of source rocks is the major controlling factor in the genesis of PG Mild negative Eu-anomaly (av. Eu/Eu* = 0.48), plots of ba-Rb-Sr in the field of anomalous granite and K/Rb ratios (av. 239) in the range that is shown by normal unevolved granite together indicate less fractionated nature of the PG Limited fractionation of metalumination-type, involving hornblende, led to occasional weak alumina saturation. Interestingly, geochemical and petrogenetic features of the studied PG broadly match with those potassic granites which are already known to host anomalously high enrichment of rare metals and rare earths in other parts of Andhra Pradesh and adjoining Karnataka.

关键词： Potassic granite Andhra Pradesh South India

Early Paleozoic basement diorite of arc-magmatism from Kutch basin, Western India

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Acta Geochimica 2024年第2期43卷 296-307页

作者： Piyush Gupta Sandeep singh Shakti singh Rathore Argha Narayan Sarkar Geochronology Laboratory KDMIPEOil and Natural Gas Corporation Ltd.9Kaulagarh RoadDehradun 248195India Department of Earth Sciences Indian Institute of TechnologyRoorkee 247667India

In this study,we report for theﬁrst time an Early Palaeozoic basement diorite from the drilled well Nirona-A in the banni Half-Graben of the Kutch basin,western *** 40Ar–39Ar dates provided a plateau age of 441.84±2.66 Ma and another pseudo plateau of 441.28±5.82 to 388.08±16.65 Ma for the basement *** ages constrain the basement formation age to the Late Ordovician-Early Silurian *** obtained basement ages are correlatable with the later part of Cambro-Ordovician alkaline magmatism that has been reported from the Huqf area in Central Oman,whereas their lithological and petrographic correlativity with base-ment diorites occurring in the Dinsi Body of Nagar Parkar igneous complex in Pakistan can also be *** geochemical studies characterized the diorite with enrich-ment of LILE(Rb,ba,and K)and LREE(La,Ce,Nd),strong depletion of HFSE(Nb,Sr,P,and ti),along with weakly negative Eu *** geochemical signatures indicate their petrogenetic afﬁliation with mantle-derived magmas,as well as their tectonic setting to be arc-related,having post-collisional continental-arc type afﬁ****440 Ma basement of Kutch,therefore,appears to rep-resent the later thermal event associated with the reworked Neoproterozoic subduction-related suite from Greater India’s northwest edge,which has implications for Gond-wana assembly in the northwest Indian subcontinent.

关键词： Kutch basin 40Ar–39Ar ages Early palaeozoic basement Continental-arc magmatism Calc-alkaline magmatism

Solvent induced shape change in CePO_4:Dy^(3+) nanophosphors and effect of metal ions: A photoluminescence study

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Journal of Rare Earths 2012年第12期30卷 1217-1224页

作者： Reena Okram N.Rajmuhon singh Department of Chemistry Manipur University

the influence of different solvents and metal ions （Li^＋, ba^2＋, Bi^3＋） on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy^3＋ doped CePO4 were investigated. Highly crystalline luminescent nanophosphors of CePO4：DY^3＋ re-dispersible in polar solvents were successfully prepared via a simple polyol route at 140 ℃. As-prepared Dy^3＋ doped CePO4 nanophosphors prepared in EG and DMF appeared to have crystalline monoclinic phase but exhibited hexagonal phase when prepared in water and water mixed solvents, the hexagonal phase transformed to monoclinic phase after heating at 900 ℃. tEM study revealed different shapes of the synthesized nanophosphors with change of solvents. the luminescence intensity of 4F9/2→6H15/2 at 478 nm （blue） was found to be more prominent than 4F9/2→6H13/2 at 572 nm （yellow）. the introduction of metal ions （Li＋, ba2＋ and Bi3＋） in CePO4：Dy3＋ led to considerable luminescent enhancement. the nanophosphors were subsequently incorporated in polymer films of PVA which showed the characteristic emissions of Dy3＋. It also served as an effective method to improve the performance of polymer materials and brought about novel properties in them.

关键词： enhanced luminescence rare earth point defects nanophosphor re-dispersible

Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins

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Journal of Environmental Sciences 2017年第4期29卷 40-47页

作者： Yue Sun Peng Zuo Junfen Luo Rajendra Prasad singh Department of Municipal Engineering Southeast University

two novel weakly basic anion exchange resins（SZ-1 and SZ-2） were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene（Cl-PS-DVB） beads with dicyclohexylamine and piperidine, respectively. the physicochemical structures of the resulting resins were characterized using Fourier transform Infrared Spectroscopy and pore size distribution analysis. the adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid（ba） was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution p H, temperature and coexisting competitive inorganic salts（Na2SO4and Na Cl） on adsorption behavior were investigated and the optimum desorption agent was *** isotherms of ba were found to be well represented by the Langmuir *** parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of ba sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. the fact that the tested resins loaded with ba can be efficiently regenerated by Na Cl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1for potential industrial application.

关键词： Benzenesulfonic acid Weakly basic anion exchange resin Adsorption Desorption

Optimisation of Adventitious Shoot Regeneration and Agrobacterium-mediated transformation in Canna × generalis(Canna Lily)

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Horticultural Plant Journal 2019年第1期5卷 39-46页

作者： Rani singh Arvind Kumar Dubey Indraneel Sanyal Plant transgenic Laboratory Division of Molecular Biology and Biotechnology CSIR-National Botanical Research Institute

Canna being ornamental plants has a significant role in agriculture, medical, economy and food industry. Canna has a limited vase life due to the rapid loss of moisture from its perianth. For improving its market value, cuticularisation of the perianth can be achieved by the expression of a heterologous cutin producing gene, using the tissue culture and transformation protocol developed in this study. Efficient, rapid and direct adventitious shoot regeneration was successfully established in Canna × generalis using recalcitrant rhizome explants. the explants were cultured on MS medium supplemented with 6-benzylaminopurine(6-ba), thidiazuron(tDZ), and kinetin. Among the four genotypes taken for tissue culture, the ‘trinacria variegata' was the best responding cultivar. And 2 mg · L^(-1)6-ba or 1.5 mg · L^(-1) tDZ along with 0.1 mg · L^(-1) IAA was optimum for their regeneration. the highest regeneration was achieved in ‘trinacria variegata'(36%) on 6-ba, 33% on tDZ while kinetin failed to evoke any regenerative responses. Regeneration was enhanced by supplementation of 100 mg · L^(-1) ascorbic acid(AsA), while, 100 mg · L^(-1) of l-cysteine or 100 mg · L^(-1) dithiothreitol(Dtt), inhibited regeneration. Shoots were observed to develop 3–5 fibrous roots on MS medium supplemented with 0.5 mg · L^(-1) indole-3-butyric acid(Iba). the plantlets were transplanted into pots and acclimatised in glasshouse with 100%survival. For transformation of Canna, rhizome explants were co-cultivated for 60 min in Agrobacterium suspension. the explants were washed with 500 mg · L^(-1) cefotaxime solution, subjected to 100 mg · L^(-1) kanamycin selection followed by excision of the shoots and culturing them on Iba-supplemented media for root development. transgene integration in the putative transformants was confirmed by PCR assay and copy number by Southern blot hybridisation analysis.

关键词： Canna regeneration rhizome UidA Agrobacterium transformation ascorbic acid 6-ba tDZ

Impact of irrigation regimes on regeneration and growth of Prosopis cineraria in arid areas of Indian thar

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Forestry Studies in China 2012年第4期14卷 320-322页

作者： Jabrinder singh Mukul BISHNOI Department of Applied Sciences HCTM Technical Campus Department of Environmental Sciences and Engineering Guru Jambheshwar University of Science and Technology

An experiment was initiated in 2008 to evaluate the impact of irrigation regimes on germination and growth patterns of seedlings of Prosopis cineraria in the arid areas of thar, India. Seeds collected from dried pods of P cineraria were sown in polybags placed in nursery beds. Different irrigation regimes were provided to different beds and data regarding germination and growth were recorded to study natural regeneration. the study revealed that irrigation regimes significantly affected the germination and growth of P cineraria under nursery conditions. the germination rate declined as the irrigation regime shifted from a daily to a fortnightly ba- sis. Height of the seedlings also declined with a decrease in the intensity of irrigation. thus, it can be concluded that germination and growth of seedlings of P cineraria under nursery conditions can be enhanced by providing irrigation at regular intervals.

关键词： germination growth irrigation regeneration Prosopis cineraria

Hydro-uvarovite from Mantle Peridotites of Naga Hills Ophiolite: A Mineral tracer for Neo-tethyan Mantle Wedge Metasomatism

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 867-877页

作者： Anisha VERENCAR Abhishek SAHA Nilanjana SORCAR Sohini GANGULY Pankaj KUMAR Atul Kumar singh CSIR-National Institute of Oceanography Dona PaulaGoa 403004India School of Earth Ocean and Atmospheric SciencesGoa UniversityTaleigao PlateauGoa 403206India National Centre for Earth Science Studies ThiruvananthapuramKeralaIndia Inter University Accelerator Centre(IUAC) New Delhi 110067India North-Eastern Hill University ShillongMeghalaya 793022India

Hydrous Cr-bearing uvarovite garnets are rare in natural occurrences and belong to the ugrandite series and exist in binary solid solutions with grossular and andradite garnets. Here, we report the occurrence of hydrous uvarovite garnet having Cr_(2)O_(3) upto 19.66 wt% and CaO of 32.12–35.14 wt% in the serpentinized mantle peridotites of Naga Hills Ophiolite(NHO), India. they occur in association with low-Cr diopsides. they are enriched in LILE(ba, Sr), LREEs, with fractionating LREE-MREE [avg.(La/Sm)_(N) = 2.16] with flat MREE/HREE patterns [avg.(Sm/Yb)_(N) = 0.95]. Raman spectra indicate the presence of hydroxyl(OH^(–)) peaks from 3500 to 3700 cm^(-1). Relative abundances in fluid mobile elements and their close association with clinopyroxenes are suggestive of the formation of uvarovite garnets through low temperature metasomatic alteration of low-Cr diopsides by hydrothermal slab fluids. the high LREE concentration and absence of Eu anomaly in the garnet further attest to alkaline nature of the transporting slab dehydrated fluid rather the involvement of low-p H solution. the chemical characteristics of the hydroxyl bearing uvarovite hosted by the mantle peridotite of NHO deviate from the classical features of uvarovite garnet, and their origin is attributed to the fluid-induced metasomatism of the sub arc mantle wedge in a suprasubduction zone regime.

关键词： uvarovite hydroxyl metasomatic alteration low-Cr diopsides serpentinization mantle peridotite

Structure inversion asymmetry enhanced electronic structure and electrical transport in 2D A3SnO(A=Ca,Sr,and ba.a.tiperovskite monolayers

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Nano Research 2023年第1期16卷 1779-1791页

作者： Syed Muhammad Alay-e-Abbas Ghulam Abbas Waqas Zulfiqar Muhammad Sajjad Nirpendra singh J.Andreas Larsson Applied Physics Division of Materials ScienceDepartment of Engineering Sciences and MathematicsLuleåUniversity of Technology97187 LuleåSweden Computational Materials Modeling Laboratory Department of PhysicsGovernment College UniversityFaisalabad 38040Pakistan Department of Energy Conversion and Storage Technical University of Denmark2800 Kgs.LyngbyDenmark Department of Physics Khalifa University of Science and TechnologyAbu Dhabi-127788United Arab Emirates Center for Catalysis and Separation(CeCaS) Khalifa University of Science and TechnologyAbu Dhabi-127788United Arab Emirates

Anti-perovskites A3SnO(A=Ca,Sr,and ba)are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry,spin–orbit coupling,and band *** provides an exciting playground for modulating their electronic properties in the two-dimensional(2D)***,we employ first-principles density functional theory(DFt)calculations by combining dispersion-corrected SCAN+rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural,thermodynamic,dynamical,mechanical,electronic,and thermoelectric properties of bulk and monolayer(one unit cell thick)A3SnO *** results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically ***,Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin–orbit coupling and inversion *** the other hand,monolayer ba3SnO exhibits Dirac cone at the high-symmetryΓpoint due to the domination of band *** on the predicted electronic transport properties,it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.

关键词： electrical transport anti-perovskites low-dimensional materials electronic structure mechanical properties

Mapping COVID-19 in India:Southern states at the forefront of new JN.1 variant

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Asian Pacific Journal of tropical Medicine 2024年第1期17卷 1-3页

作者： Rabin Debnath Arshdeep singh Kushal Seni Anjali Sharma Viney Chawla Pooja A Chawla Department of Pharmaceutical Chemistry ISF College of PharmacyG.T RoadGhal KalanMogaPunjab142001India Department of Pharmaceutical Analysis ISF College of PharmacyG.T RoadGhal KalanMogaPunjab142001India University Institute of Pharmaceutical Sciences and Research Baba Farid University of Health SciencesFaridkotPunjabIndia

A new variant,JN.1,stemming from the omicron subvariant ba.2.86,garnered the attention of the World Health Organization(WHO)as a"variant of interest."Despite its rapid global spread,especially in the US,Canada,France,Singapore,Sweden[1],and the UK,JN.1 is considered to pose minimal *** vaccinations are believed to remain effective against *** WHO underscores the importance of maintaining immunization records amid co-occurring respiratory illnesses,and epidemiologists recommend monitoring hospitalizations,particularly in areas with low vaccination rates.

关键词： Canada Mapping spite