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Formadinium Cation Doping Stabilized Ultra-deep-blue Lead Halide Perovskite Nanocrystal Light-emitting Diodes

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Chemical Research in Chinese Universities 2024年第3期40卷 556-560页

作者： Pui Kei KO Jonathan E.HALPERT Department of Chemistry The Hong Kong University of Science and TechnologyKowloonHong Kong 999077P.R.China

The halide migration effect in mixed-halide lead-based perovskite is a serious problem hindering the development of its display *** this study,we have successfully addressed this issue by reporting formadinium(FA)doped mixed-halide perovskite nanocrystals(NCs)with ultra-deep-blue emission of 450 nm,narrow bandwidth of 16 nm,and a high photoluminescence quantum yield(PLQY)of 66%.The perovskite nanocrystal light-emitting diodes(NC-LEDs)using this nanocrystal as an active layer achieved a maximum external quantum efficiency(EQE)of 0.32%,30-fold improved compared to that of pristine and stable electroluminescence(EL)spectra at 450 nm under a 4.9–8.0 V *** findings demonstrate the potential of our approach in developing stable and efficient deep blue perovskite NC-LEDs.

关键词： Halide perovskite Light-emitting diode Deep-blue

Lattice thermal conduction in cadmium arsenide

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Chinese Physics B 2022年第11期31卷 424-430页

作者： R F Chinnappagoudra M D Kamatagi N R Patil N S Sankeshwar Department of Physics S.S.Government First Grade CollegeNargund-582207KarnatakaIndia Research Resource Centre Visvesvaraya Technological UniversityBelagavi-590018KarnatakIndia Department of Physics B V B College of Engineering and TechnologyHubliKarnataka 80031India Department of Physics&Electronics CHRIST(Deemed to be University)Bangalore-560029KarnatakaIndia

Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway *** acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon *** calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering *** systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for T100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature *** detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.

关键词： dirac semimetals Cd_(3)As_(2) thermal conductivity phonon scattering

A four parameter cubic equation of state with temperature dependent covolume parameter

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Chinese Journal of Chemical Engineering 2019年第5期27卷 1132-1148页

作者： Pradnya N.P.Ghoderao Vishwanath H. Dalvi Mohan Narayan Department of Physics Institute of Chemical TechnologyMumbai 400019India Department of Chemical Engineering Institute of Chemical TechnologyMumbai 400019India

A four-parameter, Ghoderao–Dalvi–Narayan 2 cubic equation of state(GDN2 CEOS), is presented which incorporates the following: 1. The experimental value of the critical compressibility factor has been used as a fixed input parameter for calculations;2. All the parameters(a, b, c, d) of CEOS are temperature dependent functions in the subcritical region and are temperature independent functions in the supercritical region and;3. A new α function is introduced with two compound specific parameters which are estimated by matching saturated vapor pressure at two fixed temperature points Tr= 0.5, 0.7. Our formalism enables us to cast three of the four parameters of the CEOS as a function of the remaining parameter. The proposed CEOS is used to predict properties of 334 pure compounds, including saturated vapor pressure and liquid density, compressed liquid density, heat capacities at the constant pressure and volume, enthalpy of vaporization, sound velocity. To calculate thermodynamic properties of a pure compound, the present CEOS require the critical temperature, the critical pressure, the Pitzer’s acentric factor, the critical compressibility factor, and two parameters of the alpha function. The saturated liquid density predictions for pure fluids are very accurate when compared with GDN1(Ghoderao–Dalvi–Narayan 1),MPR(Modified Peng–Robinson), and PT(Patel–Teja) equations of state. Unlike MPR EOS, the proposed temperature dependent covolume parameter b in the present work satisfies all the constraints mentioned in the literature to avoid thermodynamic inconsistencies at the extreme temperature and pressure. Using van der Waals one-fluid mixing rule, the present CEOS is further used to predict bubble pressure and the vapor mole fraction of binary mixtures.

关键词： Phase equilibria Thermodynamic properties Vapor-liquid equilibria The cubic equation of state Covolume parameter Supercritical region

Nutrient Recycling from Industrial Solid Wastes and Weeds by Vermiprocessing Using Earthworms

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Pedosphere 2013年第5期23卷 668-677页

作者： A. YADAV V. K. GARG Department of Environmental Science and Engineering Guru Jambheshwar University of Science and Technology

Vermicomposting is a biotechnological process that enables the recycling of organic waste materials into manure through the combined action of earthworms and mesophilic microorganisms. In this study, a 13-week experiment was carried to vermiprocess food industry sludge mixed with different bedding materials including two weeds, water hyacinth and parthenium, as well as cow dung, in different combinations employing earthworms of the species Eisenia fetida. Eight vermibins containing one kilogram of the waste mixtures （dry weight basis） were established for vermicomposting. Vermiprocessing significantly increased nitrogen, phosphorous, and potassium contents of the mixtures. However, a decrease in pH, organic carbon, and C：N ratio was observed after vermiprocessing. The heavy metal contents in the vermicomposts were higher than the initial values but within permissible limits. These results indicated that the studied wastes can be converted into good quality manure by vermiprocessing, which indicated their agricultural values as a soil conditioner if mixed with weeds in appropriate ratios.

关键词： Eisenia fetida food industry sludge heavy metals manure vermicompost

Numerical simulation of fluidized dense-phase pneumatic conveying of powders to develop improved model for solids friction factor

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Particuology 2017年第6期15卷 42-50页

作者： Baldeep Kaur Anu Mittal S.S. Mallick Renhu Pan Soumendu Jana School of Physics and Materials Science Thapar University Patiala Punjab 147004 India Department of Mechanical Engineering Thapar University Patiala Punjab 147004 India Fujian Longking Co. Ltd. Longyan Fujian 364000 China

Accurate prediction of the solids friction factor through horizontal straight pipes is important for the reliable design of a pneumatic conveying system, but it is a challenging assignment to date because of the highly concentrated, turbulent, and complex nature of the gas-solids mixture. Power-station fly ash was transported through different pipeline configurations. Numerical simulation of the dense-phase pneumatic conveying systems for three different solids and two different air flow rates have shown that particle and actual gas velocities and the ratio of the two velocities increases in the flow direction, whereas the reverse trend was found to occur for the solids volumetric concentration. To develop a solids friction-factor model suitable for dense-phase flow, we modified an existing pure dilute-phase model by incorporating sub-models for particle and actual gas velocities and impact and solids friction factor. The solids friction-factor model was validated by using it for scale-up predictions for total pipeline pressure drops in longer and larger pipes and by comparing experimental and predicted pneumatic conveying characteristics for different solids flow rates. The accuracy of the prediction was compared with a recently developed two-layer-based model. We discussed the effect of incorporating the particle and actual gas velocity terms in the solids friction-factor model instead of superficial air velocity.

关键词： Pneumatic conveying Dense-phase Numerical analysis Pressure drop Scale-up validation

Renewable energy resources, policies and gaps in BRICS countries and the global impact

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Frontiers in Energy 2019年第3期13卷 506-521页

作者： Lakshmi PATHAK Kavita SHAH Institute of Environment and Sustainable Development Banaras Hindu UniversityVaranasi 221005India

This paper presents comparative yet extensive analysis of existing non-conventional renewable resources, energy policies and gaps in BRICS countries. An intelligent transformation to green economy to maintain natural resources is noted. Brazil has stable energy policies and is the leading producer of biofuels following hydropower until 2014 but supported wind and solar power development by tendering specific tariffs for energy generation from solar and wind. Russia needs improvement in its legal and regulatory framework with more incentives in energy policies. China is improving upon wind and hydropower but it needs strong policy measures to put cap on increased CO2 emissions. India needs revision in energy policy and requires extra incentives and consumer specific energy policies for research-infrastructure and energy generation technologies. South Africa requires lessons to increase renewable energy and reduce coal mining. Moreover, BRICS countries need to redefine their energy policies based upon their existing geographical, economical, societal and environmental conditions which will help in shaping global energy policies and more financial stability. This paper recognizes the potential of BRICS to reshape the global system paralleled with minimizing CO2 emissions. The concerted role of BRICS needs to be recognized as the leading contributor of global renewable capacity where the developed world is geared and busy to address the environmental issues.

关键词： BRICS CO2 emissions energy policies renewable

Oriented attachment(OA) mediated characteristic growth of Gd_2O_3 nanorods from nanoparticle seeds

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Journal of Rare Earths 2016年第2期34卷 158-165页

作者： Samiran Hazarika Dambarudhar Mohanta Nanoscience and Soft Matter Laboratory Department of Physics Tezpur University

Herein, we demonstrated the oriented attachment (OA) driven formation and characterization of Gd2O3 nanorods. The nanorods were synthesized via a surfactant free, inexpensive hydrothermal route and considering ~30 nm nanoparticles as the seed. While maintaining a cubic phase throughout the process, complete transformation of Gd2O3nanoparticles to nanorods was found to occur at an elevated temperature (~180 oC) of the hydrothermal reaction. The elongated Gd2O3 nanostructures, as revealed from transmission electron microscopic imaging, possessed an average diameter of ~33 nm and an approximate length of 172 nm. From the kinetics of OA process, the activation energy of formation was estimated to be ~25 kJ/mole. The existence of defect mediated radia-tive emission was ascertained from the asymmetric broadening of luminescence spectra. The defect emission arising from the Gd2O3 nanorods was nearly 1.4 times stronger than that of nanoparticles. The morphological evolution and growth kinetics were discussed along with the luminescence and electron paramagnetic resonance features.

关键词： nanorod hydrothermal oriented attachment rare-earth oxide

Citric acid:An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

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Chinese Chemical Letters 2011年第4期22卷 389-392页

作者： Radhakrishnan Mahesh Arghya Kusum Dhar Tara Sasank T.V.N.V. Sappanimuthu Thirunavukkarasu Thangaraj Devadoss Birla Institute of Technology & Science PilaniRajasthan-333031India Orchid Chemicals and Pharmaceutical Ltd. SholinganallurChennai-600119India

The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol,and most of the r... 详细信息

关键词： Quinoxalins Citric acid o-Phenylenediamines 1 2-Dicarbonyl compounds Green catalyst

Synthesis of Nanocrystalline FeS_2 with Increased Band Gap for Solar Energy Harvesting

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Journal of Materials Science & Technology 2014年第8期30卷 770-775页

作者： Somnath Middya Animesh Layek Arka Dey Partha Pratim Ray Department of Physics Jadavpur University

In this paper,we have reported the synthesis of FeS2 of higher band gap energy（2.75 eV） by using capping reagent and its successive application in organic-inorganic based hybrid solar *** route was adopted for preparing iron pyrite（FeS2） nanoparticles with capping reagent *** quality of synthesized FeS2 material was confirmed by X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric analyzer,and Raman *** optical band gap energy and electro-chemical band gap energy of the synthesized FeS2 were investigated by UV-vis spectrophotometry and cyclic *** band gap engineered FeS2 has been successfully used in conjunction with conjugated polymer MEHPPV for harvesting solar *** energy conversion efficiency was obtained as 0.064%with a fill-factor of 0.52.

关键词： Hydrothermal synthesis FeS2 nanoparticles Optical characterization Energy band gap