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Crystal Structure Theory and Applications 2016年第2期5卷 17-23页

作者： Shahida Akhter deba prasad paul Department of Physics University of Chittagong Chittagong Bangladesh

The growth kinetics of LSCO and YBCO single crystals from high temperature solution of LSCO-CuO solute-solvent and YBCO-CuO solute-solvent systems has been investigated. Based on regular solution model and classical nucleation theory, the thermodynamical data investigated for the systems are used to determine the nucleation parameters: interfacial free energy, metastable zone-width, volume free energy, critical energy barrier for nucleation and radius of critical nucleus for LSCO and YBCO which leads to the understanding of the nucleation phenomena of LSCO and YBCO.

关键词： LSCO YBCO Interfacial Energy Metastable Zone-Width

Magnetic Properties of Cu1-xZnxFe2 O4Ferrites with the Variation of Zinc Concen-tration

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Journal of Modern Physics 2012年第5期3卷 398-403页

作者： Shahida Akhter deba prasad paul Md. Abdul Hakim Shireen Akhter Sheikh Manjura Hoque Hari Narayan Das Department of Physics University of Chittagong Materials Science Division Atomic Energy Centre

Cu-Zn ferrite with general formula of Cu1-xZnxFe2 O4 with a range from x = 0.0 to 0.7 (in steps of 0.1) was prepared by using standard ceramic techniques. The confirmation of sin-gle-phase formation was carried out by employing X-ray diffraction technique. Some of the magnetic properties were measured, such as Curie temperature, the complex permeability and low field hysteresis loop. It was found that Curie temperature Tc decreases from 464?C to 20?C. The real part of initial permeability, μ′ in-crease with increasing Zn contents up to x = 0.5 after that it decreases with higher Zn content. Low field hysteresis measurement was carried out at room temperature and this measurement with the increase of Zn2+ ions yields the increase of saturation magnetic induction (By) and magnetic remanance (Br) up to x = 0.4 thereafter it decreases. The decrease in corecivity (Hc) and hysteresis loss is observed for all samples. In view of this, the possible changes in magnetic properties with the increase in Zn concentration are un-dertaken.

关键词： XRD Curie Temperature Initial Permeability Hysteresis Loop Coercivity

Synthesis, Structural and Physical Properties of Cu1–xZnxFe2O4Ferrites

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Materials Sciences and Applications 2011年第11期2卷 1675-1681页

作者： Shahida Akhter deba prasad paul Md. Abdul Hakim Dilip Kumar Saha Md. Al-Mamun Alhamra Parveen 不详

Zn substituted Cu-Zn ferrites with a composition Cu1-xZnxFe2O4 have been synthesized by standard double sintering ceramic method and characterized by X-ray diffraction. The single-phase cubic spinel structure of all the samples has been confirmed from X-ray diffraction analyses. The lattice constant is found to increase linearly with the manganese content obeying Vegard’s law. This increase in lattice parameter is explained in terms of the sizes of component ions. It is well known that density plays a key role in controlling the properties of polycrystalline ferrites. The X-ray and bulk densities of the Cu-Zn ferrite is significantly decreased whereas porosity increased with increasing Zn concentration, thereby giving an impression that zinc might be helping in the densification of the materials. SEM micrographs exhibit a decrease in grain size with increasing Zn content. The real part of initial permeability, μ′ increase with increasing Zn contents upto x = 0.5 after that it decreases with higher Zn content.

关键词： Ferrites XRD Lattice Parameter Density Porosity Permeability

Study of the Bulk Magnetic and Electrical Properties of MgFe2O4Synthesized by Chemical Method

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Materials Sciences and Applications 2011年第11期2卷 1564-1571页

作者： Sheikh Manjura Hoque M. Abdul Hakim Al Mamun Shireen Akhter Md. Tanvir Hasan deba prasad paul Kamanio Chattopadhayay 不详

Nanocrystalline Magnesium ferrite has been prepared by chemical co-precipitation technique. Structural characterization has been performed by X-ray diffraction. Formation of ferrites has also been studied by using FTIR. Frequency dependence of real and imaginary part of initial permeability has been presented for the samples sintered at different temperatures. Real part of initial permeability, increases with the increase of grain growth. The loss component repre- sented by imaginary part of initial permeability decreases with frequency up to the measured frequency of this study of 13 MHz. Curie temperatures have been determined from the temperature dependence of permeability. Curie temperatures for the samples of this composition do not vary significantly with the variation of sintering temperatures. B-H loop measurements have been carried out by B-H loop tracer. Transport property measurements haven been carried out by electrometer and impedance analyzer.

关键词： MgFe2O4 Nanograins Complex Initial Permeability B-H Curves Transport Properties

Towards a sustainable geoliner construction in landflls by potential blending of fly ash with kaolin clay alternative:a review with an insight to Indian scenario

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Waste Disposal and Sustainable Energy 2024年第2期6卷 243-258页

作者： Kshitij Kumar Biswajit paul Department of Environmental Science and Engineering Indian Institute of Technology(Indian School of Mines)Dhanbad 826004JharkhandIndia

Electricity generated through coal-based Thermal Power Plants(TPPs)has played a pivotal role in shaping modern civiliza-tion,revolutionizing industries,and improving the quality of life for billions of people *** TPPs contribute to about 37%-40%of the global energy *** production,in turn,has a direct impact on the economy of any *** from this boon to humankind,these TPPs combusting coal as their primary fuel also have specific environmen-tal impacts,the major ones being water,air,and soil pollution due to unscientific disposal of high-quantity fly ash produced *** we can put this ash to good use,it may assist us in mitigating the pollution caused by *** there are many conventional uses of fly ash,such as a pozzolanic material in the cement industry,more pathways need to be discovered to balance the high generation quantities with ***,a detailed description of its use in potential geoliner applications is presented in this article.A geoliner or a landfill liner acts as a virtually impenetrable layer to mitigate the leachate penetration into the underneath subsoil and groundwater,thus preventing *** are presently some studies that support the use of only fly ash in such ***,the properties of the geoliners using it are not so good to significantly mitigate environmental degradation owing to its high permeability and low densification *** bentonite conventionally used has limited deposits and is mined intensively for its use as a natural *** depos-its must also be conserved,and an alternative material that may serve similar application benefits,like bentonite,must be *** desired aim can be fulfilled if we blend this combustion residue with other suitable materials(such as kaolinite clay)with low ***,the article focuses on the possibilities of blending fly ash with different clays for geoliner construction to improve the in

关键词： Fly ash-Geoliner Environmental management Composite liner systems Bentonite Kaolin clay

Strain-dependent alpha-synuclein spreading in Parkinson's disease and multiple system atrophy

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Neural Regeneration Research 2024年第12期19卷 2581-2582页

作者： Shuyu Zhang paul Lingor Department of Neurology School of MedicineUniversity Hospital rechts der IsarTechnical University of MunichMunichGermany Department of Neurology University Medical Center GöttingenGöttingenGermany Center for Biostructural Imaging of Neurodegeneration University Medical Center GöttingenGöttingenGermany

Parkinson's disease(PD) and atypical Parkinsonian syndromes,such as multiple system atrophy(MSA) and Dementia with Lewy bodies,are neurodegenerative movement disorders characterized by the accumulation of alphasynuclein(a-syn) *** a-syn aggregates propagate throughout the brain in a prion-like manner,where pathological a-syn recruits endogenous a-syn to form insoluble *** forms representing intermediates on the way to insoluble aggregates result in the most pronounced neurotoxic effects.

关键词： atrophy endogenous atypical

Tensor perturbations from bounce inflation scenario in f(Q)gravity

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 78-92页

作者： Kun Hu Tanmoy paul Taotao Qiu Institute of Astrophysics Central China Normal UniversityWuhan 430079China School of Physics Huazhong University of Science and TechnologyWuhan 430074China National Institute of Technology Jamshedpur Department of PhysicsJamshedpur 831014India

In this paper,we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity,namely f(Q)theory,and investigate the tensor perturbations *** is well-known,the tensor perturbations generated in the very early Universe(inflation and pre-inflation regions)can account for the primordial gravitational waves(PGWs)that are to be detected by the next generation of GW *** discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation *** general form of the tensor power spectrum is obtained both for large as well as small scale *** a result,we show both kinds of modes(short or long wavelength modes),and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves’amplitude in the background of the f(Q)bounce-inflation ***,we study the LQC-like scenario as a specific case of our model,in which,the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales.

关键词： bounce cosmology modified gravity cosmological perturbations

Smoking of Carica papaya in Nigeria:The rationale,the public health effects and policies for intervention

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Asian Pacific Journal of Tropical Medicine 2024年第3期17卷 95-96页

作者： Abolaji paul Adekeye Mental Health Department Federal Teaching HospitalIdo-EkitiEkiti StateNigeria Mental Health Department Afe Babalola UniversityAdo-EkitiEkiti StateNigeria

Psychoactive substance use is characterized by the habitual use of substances that have significant effects in altering the activities of neurotransmitters in certain regions of the ***,these alterations manifest as c... 详细信息

关键词： rational behaviour emotional

Surface engineering with ionic polymers on membranes for boron removal

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 61-69页

作者： Xiting Zhang Chenyi Fang J paul Chen Sui Zhang Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117576Singapore Department of Civil and Environmental Engineering National University of SingaporeSingapore 119260Singapore College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial *** research efforts performed post-modification of reverse osmosis membranes to enhance boron rejection,which is usually accompanied by substantial sacrifice in water *** study delves into the surface engineering of low-pressure reverse osmosis membranes,aiming to elevate boron removal efficiency while maintaining optimal salt rejection and water *** were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and *** surfaces became smoother and more hydrophilic after *** optimum membrane exhibited a water permeability of 9.2±0.1 L·m^(-2)·h^(-1)·bar^(-1),NaCl rejection of 95.8%±0.3%,and boron rejection of 49.7%±0.1% and 99.6%±0.3% at neutral and alkaline pH,*** water permeability is reduced by less than 15%,while the boron rejection is 3.7 times higher compared to the blank *** research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.

关键词： membrane low-pressure reverse osmosis boron surface engineering

The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： paul B.Wignall David P.G.Bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter