检索结果-南通市图书馆

Ultraviolet to visible frequency-conversion properties of rare earths doped glass ceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Rare earths 2011年第5期29卷 484-488页

作者： Y.Hatefi n.Shahtahmasebi A.Moghimi e.Attaran Department of Physics Imam Hossein University nano-Research Centre of the Ferdowsi University of Mashhad Department of Physics Ferdowsi University of Mashhad Department of Chemistry Imam Hossein University

nd3＋,eu3＋ and Tb3＋ ions doped transparent chlorophosphate glass ceramics were prepared and their frequency-conversion properties were studied. X-ray diffraction （XRD） patterns evidenced the formation of expected halide nanocrystals. The absorption,excitation and emission spectra investigation indicated that some of rare earth （Re） ions were trapped in low phonon energy halide nanocrystals,and therefore an efficient down frequency-conversion was observed. The comparative spectroscopic studies of Re doped samples suggested that the glass ceramics systems are potentially applicable as efficient ultraviolet to visible frequency-conversion photonics materials.

关键词： chlorophosphate glass down frequency-conversion glass ceramic photonic devices nanocrystal rare earth ions

Metal separations of interest to the Chinese metallurgical industry

在线全文

学校读者我要写书评

暂无评论

Journal of Rare earths 2010年第S1期28卷 22-29页

作者： S.R.Izatt n.e.Izatt R.L.Bruening IBC Advanced Technologies Inc.856 E.Utah Valley DriveAmerican ForkUT 84003U.S.A.

IBC Advanced Technologies’ Molecular Recognition Technology(MRT) SuperLig products selectively and rapidly bind with target species enabling their selective removal from *** MRT process can produce a high purity separation product of maximum added value at a competitive *** products have high selectivity for many target species which can include metal ions,anions,and neutral *** operation,the SuperLig product is first placed in a packed column.A solution containing a mixture of the target species and other chemical species is then passed through the *** target species is removed selectively by the SuperLig product,the column is washed to remove residual feed solution,and the target species is recovered by a minimal quantity of *** result is a pure and concentrated species that can be kept for its value or disposed of *** process is environmentally and ecologically friendly with no organic solvents being *** paper provides a review of some examples of applications of MRT to separations of interest to the Chinese metallurgical *** are several applications of MRT,including Pd separations from Pt metal refinery streams and low-grade spent catalyst wastes,Rh recovery from spent auto catalyst and other feeds,Re removal from selected impurity ions,Cd removal from Co electrolyte,Bi removal from Cu electrolyte,In and Ge separations from difficult matrices,and removal of bivalent first transition series and other metal ions from acid mine drainage(Berkeley Pit,Montana).Finally,the potential application of MRT to separations involving the recovery of rare earth metals and Li from low-level waste solutions and end-of-life products is discussed.

关键词： selective and environmentally friendly metal separations molecular recognition technology SuperLig platinum group metals minor metals transition series metals rhenium cadmium indium germanium bismuth rare earth metals lithium

environmental performance assessments of different methods of coal preparation for use in small-capacity boilers: experiment and theory

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2023年第5期10卷 57-71页

作者： A.n.Kozlov e.P.Maysyuk I.Yu.Ivanova Melentiev energy Systems Institute of Siberian Branch of the Russian Academy of Sciences Irkutsk130Lermontov664033Russia

The purpose of this article is to receive environmental assessments of combustion of different types of coal fuel depending on the preparation(unscreened,size-graded,briquetted and heat-treated)in automated boilers and boilers with manual *** assessments were made on the basis of data obtained from experimental methods of coal preparation and calculated methods of determining the amount of pollutant and greenhouse gas emissions,as well as the mass of ash and slag *** main pollutants from coal combustion are calculated:particulate matter,benz(a)pyrene,nitrogen oxides,sulfur dioxide,carbon *** the greenhouse gases carbon dioxide is *** a result of conducted research it is shown that the simplest preliminary preparation(size-graded)of coal significantly improves combustion efficiency and environmental performance:emissions are reduced by 13%for hard coal and up to 20%for brown *** introduction of automated boil-ers with heat-treated coal in small boiler facilities allows to reduce emissions and ash and slag waste by 2-3 *** best environmental indicators correspond to heat-treated lignite,which is characterized by the absence of sulfur dioxide emissions.

关键词： Coal preparation Automated and hand-fed coal boilers environmental performance metrics

Geochemistry and petrogenetic evolution of metasedimentary rocks in Bunu Area,part of Kabba-Lokoja-Igarra schist belt,SW nigeria

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2022年第5期41卷 765-788页

作者： M.S.Kolawole e.C.Chukwu A.n.Agibe Department of Geology Federal UniversityOye-EkitiEkiti StateNigeria

Field and geochemical studies of the Bunu area,SW nigeria,were carried out on gneiss-metasedimentary rocks that consist of migmatised gneiss,quartz-mica schist,and foliated and massive *** gneissmetasedimentary rocks are interbedded with meta-igneous rock(amphibolite),all of which are intruded by granitoid and cut by basic and felsic *** data on major,trace,and rare earth elements of these rocks from the area were used to speculate on the petrogenetic and geodynamic evolution of the rocks in the ***,the metasedimentary rocks in the area have a restricted range of major oxides such as SiO_(2)and Al_(2)O_(3)with low average values of FeO,MnO,CaO,and *** of average values of HSFe such as Zr,nb,and Y are moderately high in migmatitic gneiss,quartzmica schist,and low in both massive and foliated quartzite.ΣLRee average values are 124.25,132.41,and18.64 ppm respectively for migmatite gneiss,quartz-mica schist,and low in both massive and foliated *** rocks are also generally enriched in Ba,Cs,Pb,U,Cr,Rb,and Zr and depleted in Be,Sr,Ti,Mo,Th,and *** enrichment–depletion in major oxides and trace elements of the rocks in this area is probably a consequence of the movement of metamorphic remobilized fluids within the rocks in the area during the Pan-African or earlier events as noted in the adjacent egbe-Isanlu Schist belt.A further geochemical characterisation of the rocks in the area using Log(na_(2)O/KO)vs Log(SiO_(2)/Al_(2)O_(3)indicates that while the protolith of migmatised gneiss and quartzmica schist are greywackes to litharenite in compositions that of quartzites are sublitharenite to quartz *** the ternary plot of Al_(2)O_(3)-(CaO+na_(2)O)-KO for metasedimentary rocks in the area,most migmatitic gneiss and quartz-mica schist rocks plot close to average shale while quartzites mostly tend to illite compositions and almost toward the Al_(2)O_(3)-apex of the diagram attesting to depletion of

关键词： Geochemical studies Metasedimentary rocks Geodynamic activities Protolith Passive continental margins

The effect of electric vehicle energy storage on the transition to renewable energy

在线全文

学校读者我要写书评

暂无评论

Green energy and Intelligent Transportation 2023年第1期2卷 16-25页

作者： efstathios e.Michaelides Viet n.D.nguyen Dimitrios n.Michaelides Department of engineering TCUFort WorthTX76132USA University Wisconsin-Madison MadisonWIUSA

The most viable path to alleviate the Global Climate Change is the substitution of fossil fuel power plants for electricity generation with renewable energy *** substitution requires the development of very large energy storage capacity,with the inherent thermodynamic irreversibility of the storage-recovery ***,the world experiences a significant growth in the numbers of electric vehicles with large batteries.A fleet of electric vehicles is equivalent to an efficient storage capacity system to supplement the energy storage system of the electricity *** based on the hourly demand-supply data of eRCOT,a very large electricity grid,show that a fleet of electric vehicles cannot provide all the needed capacity and the remaining capacity must be met by *** though the storage capacity of the batteries is close to 1–2%of the needed storage capacity of the grid,the superior round-trip storage efficiency of batteries reduces the energy dissipation associated with the storage and recovery processes by up to 38%and the total hydrogen storage capacity by up to 50%.The study also shows that anticipated improvements in the round-trip efficiencies of batteries are almost three times more effective than improvements in hydrogen storage systems.

关键词： Fossil fuel substitution Decarbonization electric vehicles energy storage Vehicle to grid Batteries

experimental study of shear properties of 3D woven composite using digital image correlation and acoustic emission

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第2期36卷 448-459页

作者： e.M.Strungar A.S.Yankin e.M.Zubova A.V.Babushkin A.n.Dushko Center of experimental Mechanics Perm National Research Polytechnic University614990 PermRussian Federation engineering Center PJSC“UeC-Saturn” 152903 RybinskRussian Federation

This work is dedicated to the experimental study of the shear properties of three-dimensional reinforced composites taking into account their structural features,in Iosipescu *** strains have been determined using Vic-3D non-contact three-dimensional digital optical *** evolution of inhomogeneous strain fields on the surface of composite specimens of the structure under study has been *** variants of strain averaging in the specimen working area have been analyzed using Vic-3D ***-6 acoustic emission system has been used to assess the structural integrity of composite materials under loading.

关键词： Carbon-fiber composite 3D reinforced composite Digital image correlation Acoustic emission technique Iosipescu test

Influence of temperature on tunneling-enhanced recombination in Si based p–i–n photodiodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2014年第8期35卷 10-14页

作者： P.Dalapati n.B.Manik A.n.Basu Condensed Matter Physics Research Center Department of Physics Jadavpur University

We investigate the dominant dark current transport mechanism in Si based p-i-n photodiodes, namely, BPW 21R, SFH 205FA and BPX 61 photodiodes in the temperature range of 350 to 139 K. The forward current- voltage characteristics of these photodiodes are explained via the tunneling enhanced recombination model, which gives a quantitative description of the electronic mechanism in the p-i-n junction photodiodes. The observed tem- perature dependence of the saturation current and the diode ideality factor of these devices agree well with theo- retical predictions; the analysis also indicates the importance of doping for enhancement of tunneling. The present study will be helpful in applying the devices at low temperature ambience.

关键词： photodiode low temperature ideality factor reverse saturation current tunneling energy

A new Method of Synthesis of Azo Schiff Base Ligands with Azo and Azomethine Donors： Synthesis of n-4-Methoxybenzylidene-2-（3-hydroxyphenylazo）-5-hydroxyaniline and Its nickel（Ⅱ） Complex

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2007年第6期25卷 869-871页

作者： OFORKA, n. C. MKPenIe, V. n. Department of Pure and Industrial Chemistry University of Port Harcourt P. M. B. 5323 Port Harcourt Nigeria

A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, n-4-methoxybenzylidene-3-hydroxyphenylamine （SB） derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel（Ⅱ） complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio （M ： L = 1 ： 2） and suggested a square planar geometry for the complex.

关键词： synthesis azo compound Schiff base ligand azo and azomethine donor

Balanced and Unbalanced Components of Moist Atmospheric Flows with Phase Changes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2019年第6期40卷 1005-1038页

作者： Alfredo n.WeTZeL Leslie M.SMITH Samuel n.STeCHMAnn Jonathan e.MARTIn Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of engineering Physics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Atmospheric variables(temperature, velocity, etc.) are often decomposed into balanced and unbalanced components that represent low-frequency and high-frequency waves, respectively. Such decompositions can be defined, for instance, in terms of eigenmodes of a linear operator. Traditionally these decompositions ignore phase changes of water since phase changes create a piecewise-linear operator that differs in different phases(cloudy versus non-cloudy). Here we investigate the following question: How can a balanced–unbalanced decomposition be performed in the presence of phase changes? A method is described here motivated by the case of small Froude and Rossby numbers,in which case the asymptotic limit yields precipitating quasi-geostrophic equations with phase changes. Facilitated by its zero-frequency eigenvalue, the balanced component can be found by potential vorticity(PV) inversion, by solving an elliptic partial differential equation(PDe), which includes Heaviside discontinuities due to phase changes. The method is also compared with two simpler methods: one which neglects phase changes, and one which simply treats the raw pressure data as a streamfunction. Tests are shown for both synthetic, idealized data and data from Weather Research and Forecasting(WRF) model simulations. In comparisons, the phase-change method and no-phase-change method produce substantial differences within cloudy regions, of approximately 5K in potential temperature, due to the presence of clouds and phase changes in the data. A theoretical justification is also derived in the form of a elliptic PDe for the differences in the two streamfunctions.

关键词： Potential vorticity inversion Moist atmospheric dynamics Slow-fast systems Balanced-unbalanced decomposition elliptic partial differential equations