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1.
Europium and terbium complexes with strong fluorescence intensity and long fluorescence lifetime were prepared. By replacing half of the europium or terbium ion with M (M = Zn^2+, Cd^2+, and Cr^3+) using the doped method, and then incorporating it with 18-crown-6 ether and terephthalic acid, six heteronuclear samples EuZnLL'Cl3·3H2O(1), EuCdLL2'Cl3·5H2O(2), EuCrLL'Cl4· 4H2O(3), TbZnLL'Cl3·4H2O(4), TbCdLL'2Cl3·4H2O(5), and TbCrLL'2Cl4 ·4H2O(6) (L = terephthalic acid, L'= 18-Crown-6 ether) were obtained. The elemental analysis, molar conductivities, rare earth complexometry, Fourier Transform Infrared Spectroscopy (FT-IR), ultraviolet (UV), TGA, fluorescence intensity, and fluorescence lifetime of the samples were measured. The results showed that there were good luminescence properties for heteronuclear complexes (1), (2), (4), and (5), which were even stronger than those of the homonuclear complexes Eu2LL'2Cl4·4H2O and Tb2LL'2Cl4 ·4H2O, but the luminescence properties of EuCrLL'Cl4·4H2O, TbCrLL'Cl4·4H2O were very weak. A possible luminescence mechanism was suggested by the organic-inorganic doped mechanism and the law of intramolecular energy transfer.  相似文献   

2.
3.
《Hydrometallurgy》1987,19(2):137-157
Activities of HCl in the HClCuCl2, HClNiCl2 and HClFeCl3 aqueous solution systems, which cannot be determined by the e.m.f. method, were calculated at 298 K by applying the McKay-Perring method based on the measured water activities. The water activities of these solutions and those of HClNaCl solutions were determined by a transpiration method, and the b values involved in the corrected Zdanovskii equation were evaluated as a function of water activity. The calculated values of a(HCl) of the aqueous solution system of HClNaCl agreed well with those determined by the e.m.f. method at both dilute and concentrated HCl levels. The activities of HCl in the solution systems being studied were then calculated. The change in a(HCl) with an increase in the chloride concentration is attributable to the change in ionic strength of the solution, and thus the concentration of the chemical species present in the solution.  相似文献   

4.
Intraditionalconvertersteelmakingprocess ,therephosphorizationofliquidsteelcausedbyladleslagstakesplacebecausetheoxidabilityandbasicityofslagsaredecreasedwhenthedeoxidizingandal loyingoperationsofsteelarecarriedoutinladle .Atpresent ,mainmeasuresofcontrollingrephosphori zationincludeincreasingoriginalbasicityandoxid abilityofslags ,whichcanincreasethemeltingpoint ,viscidityofslagsandtheamountofworkfordeoxidizationandalloyforalloying .Atthesametime ,theslagswithhighoxidabilityincreasetheox ygen…  相似文献   

5.
2 mercaptobenzothiazolewasfirstreportedbyHofmann[1 ] in 1 887.Ithasbeenusedasanacceleratorinthevulcanizationofrubberformanyyears .Todayitisstillbeingusedasamainacidicacceleratorinrubberindustry .Butithasdisadvantagesofvulcanizationreversionandeasyscorch[2 ] whe…  相似文献   

6.
These minutes are the official record of the actions of the Association taken during the year by both the Board of Directors (the Board) and the Council of Representatives (Council). The roll of representatives was called at each Council meeting, and more than a quorum answered to their names. Reference is made in these minutes to various reports, some of which will be published elsewhere. Copies of these reports were distributed to Council and are on file in the Central Office. As long as the supply lasts, extra copies of many of the reports are available from the Central Office. These minutes are arranged in topical rather than chronological order, and subheadings are used when appropriate. The main topical headings are I. Minutes of Meetings; II. Elections, Awards, Membership, and Human Resources; III. Ethics; IV. Board of Directors; V. Divisions and State, Provincial, and Territorial Psychological Associations; VI. Organization of the APA; VII. Publications and Communications; VIII. Convention Affairs; IX. Educational Affairs; X. Professional Affairs; XI. Scientific Affairs; XII. Public Interest; XIII. Ethnic Minority Affairs; XIV. International Affairs; XV. Central Office; and XVI. Financial Affairs. Changes to the language of the American Psychological Association (APA) Bylaws, Association Rules, or motions of the items are noted as follows throughout these proceedings: Bracketed material is to be deleted; underlined material is to be added. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

7.
Synthesis, Characterization and Fluorescence Studies on Complexes of Terbium with Phenylglyoxylic Acid, 2,2-Dipyridine, 1,10-Phenanthroline, Triphenyl Phosphine Oxide  相似文献   

8.
CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts.  相似文献   

9.
These minutes are the official record of the actions of the American Psychological Association taken during the year by both the Board of Directors and the Council of Representatives. Reference is made in there minutes to various reports, some of which will be published elsewhere. Copies of the reports are distributed to Council and are on file in the Central Office. The minutes are arranged in topical, rather than chronological, order, and subheading are used when appropriate. The main topical headings are I. Minutes of Meetings; II. Elections, Awards, Membership, and Human Resources; III. Ethics; IV. Board of Directors; V. Divisions and State and Provincial Associations; VI. Organization of the APA; VII. Publications and Communications; VIII. Convention Affairs; IX. Educational Affairs; X. Professional Affairs; XI. Scientific Affairs; XII. Public Interest; XIII. Ethnic Minority Affairs; XIV. International Affairs; XV. Central Office; XVI. Financial Affairs; and XVII. Communications Concerning Outside Organizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
These minutes are the official record of the actions of the Association taken during the year by both the Board of Directors (the Board) and the Council of Representatives (Council). The roll of representatives was called at each Council meeting, and more than a quorum answered to their names. Reference is made in these minutes to various reports, some of which will be published elsewhere. Copies of these reports were distributed to Council and are on file in the Central Office. As long as the supply lasts, extra copies of many of the reports are available from the Central Office. These minutes are arranged in topical rather than chronological order, and subheadings are used when appropriate. The main topical headings are I. Minutes of Meetings; II. Elections, Awards, Membership, and Human Resources; III. Ethics; IV. Board of Directors; V. Divisions and State, Provincial, and Territorial Associations; VI. Organization of the APA; VII. Publications and Communications; VIII. Convention Affairs; IX. Educational Affairs; X. Professional Affairs; XI. Scientific Affairs; XII. Public Interest; XIII. Ethnic Minority Affairs; XIV. International Affairs; XV. Central Office; and XVI. Financial Affairs. Changes to the language of the American Psychological Association (APA) Bylaws, Association Rules, or motions of the items are noted as follows throughout these proceedings: Bracketed material is to be deleted; underlined material is to be added. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   

11.
The standard Gibbs energies of formation of Fe2Mo3O12, Fe2Mo3O8, FeMoO4, and Fe2MoO4 of the Fe-Mo-O ternary system and the μ phase of the Fe-Mo binary system have been determined by measuring electromotive forces of galvanic cells having an Y2O3-stabilized ZrO2 solid electrolyte. The results are as follows: $$\begin{gathered} \Delta _f G^\circ (FeMoO_4 )/kJ \cdot mol^{ - 1} = - 1053.5 + 0.2983(T/K) \pm 0.4 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_8 )/kJ \cdot mol^{ - 1} = - 2347 + 0.6814(T/K) \pm 1 \hfill \\ Temperature range: 1112 to 1339 K \hfill \\ \Delta _f G^\circ (Fe_2 Mo_3 O_{12} )/kJ \cdot mol^{ - 1} = - 2993 + 0.9105(T/K) \pm 2 \hfill \\ Temperature range: 1040 to 1145 K \hfill \\ \Delta _f G^\circ (Fe_{0.58} Mo_{0.42} )/kJ \cdot mol^{ - 1} = - 18.7 + 0.0117(T/K) \pm 0.1 \hfill \\ Temperature range: 1162 to 1223 K \hfill \\ \Delta _f G^\circ (Fe_2 MoO_4 )/kJ \cdot mol^{ - 1} = - 1174 + 0.342(T/K) \pm 1 \hfill \\ Temperature range: 1243 to 1466 K \hfill \\ \end{gathered} $$ where the standard pressure is 1 bar (100 kPa).  相似文献   

12.
A gas phase equilibration technique was used to generate Na2O isoactivity data at high-silica compositions in the systems Na2O-CaO-SiO2, Na2O-MgO-SiO2, and Na2O-CaO-SiO2-(10 and 20 wt pct) A12O3 at 1400 °. Loga Na 2 O values referenced to pure liquid Na2O at 1400 ° as standard state ranged from about ?8.0 to ?7.0. Silica activities were calculated in the Na2O-CaO-SiO2 system using the Gibbs-Duhem equation. Richardson’s model for ideal mixing of basic oxides in silica was applied to the Na2O-CaO-SiO2 system. The model shows best fit when cationic mixing is assumed to occur on divalent sites. The alkali retention in slags has been described using a defined “sodium capacity”. The temperature variation of alkali retention was estimated, and the resulting sodium capacity was used to evaluate alkali stability in blast furnace slags.  相似文献   

13.
The band structures,density of states,phonon,optical properties,and thermodynamic properties of β-La_2S_3 were calculated from first-principles using the plane-wave pseudopotential method.First,the structures were fully relaxed through the first-principles method.Then,the zone-center phonon-mode frequencies were evaluated within the framework of density functional perturbation theory.Properties related to the structure,phonons,optics,elastic constants,and thermodynamics of β-La_2S_3 were reported.The dielectric function,refractive index,absorption coefficient,extinction coefficient,infrared(IR) reflectance,energy,heat capacity,and Debye temperature spectra were also given β-La_2S_3 was a direct-gap semiconductor,and calculation indicated that its energy gap was 0.191 eV.From the phonon spectra,it could be concluded that the lattice dynamics were stable.A strong IR reflection occurred in a range of 0-1000 nm,arising from several strong IR-active modes,resulting in poor transmission properties.Relatively good transmission properties were observed in the range above 2000 nm,with low reflectivity and dissipation due to the absence of IR-active or weak modes.  相似文献   

14.
~~China's imports and exports of tungsten,molybdenum,tin and antimony by category~~  相似文献   

15.
Temperature and solute concentration effects on the friction stress, σo, of cast (texture-free) polycrystals of pure Mg, and of Mg-Al, -Zn and -Gd binary solid solutions are discussed using phenomenological arguments. The temperature effects on the pure metal suggest that σo relates to the ratio between the CRSS of prism and basal slip, against early suggestions that it should only relate to the CRSS for basal slip. Solid solution softening upon prism slip accounts for the minima in σo at ~ 0.5 at. pct in Mg-Zn and Mg-Gd alloys. In the concentrated alloys, solute-specific hardening effects upon slip and twinning lead to diverging behaviors: in Mg-Al and Mg-Zn, σo remains below that of pure Mg. Strong short-range order by Gd leads to a steep monotonic increase, and to a value larger in compression than in tension due to the activation of {10-11} twinning at high concentrations. The negative σo of the dilute Mg-Zn alloys is an artifact created by the tension/compression asymmetry stemming from the polar character of {10-12} twinning.  相似文献   

16.
The complex of [Tb(2-IBA)3(H2O)2]n (2-IBA=2-iodobenzoate) was prepared by solvent method from TbCl36H2O and 2-iodo-benzoic acid. The crystal structure was determined with X-ray single-crystal diffraction. The X-ray diffraction analysis indicated that the title complex crystallized in triclinic crystal system and Pi space group. The Tb3+ ion was coordinated by six oxygen atoms from five 2-IBA ligands and two oxygen atoms from two water molecules, giving a distorted square-antiprism polyhedral geometry. The carboxyl groups were bonded to the Tb3+ ions with bidentate-bridging and bidentate-chelating coordination modes. The adjacent Tb3+ ions were linked by two bidentate-bridging 2-IBA ligands, forming I-D chain structure. The fluorescence spectrum of the complex showed four main peaks at 489, 543, 587, and 618 nm, Corresponding to 5D4→7F (J=6-3) transition emissions of the Tb3+ ion, respectively.  相似文献   

17.
The complex of [Tb(2-IBA)3(H2O)2]n (2-IBA=2-iodobenzoate)was prepared by solvent method from TbCl3·6H2O and 2-iodobenzoic acid. The crystal structure was determined with X-ray single-crystal diffraction. The X-ray diffraction analysis indicated that the title complex crystallized in triclinic crystal system and Pī space group. The Tb3+ ion was coordinated by six oxygen atoms from five 2-IBA ligands and two oxygen atoms from two water molecules, giving a distorted square-antiprism polyhedral geometry. The carboxyl groups were bonded to the Tb3+ ions with bidentate-bridging and bidentate-chelating coordination modes. The adjacent Tb3+ ions were linked by two bidentate-bridging 2-IBA ligands, forming 1-D chain structure. The fluorescence spectrum of the complex showed four main peaks at 489, 543, 587, and 618 nm, corresponding to 5D47FJ (J=6?3) transition emissions of the Tb3+ ion, respectively.  相似文献   

18.
Preparation and Characterization of CeO2 Superfine Powder   总被引:6,自引:5,他引:1  
The CeO2 superfine powder was prepared by the co-precipitation method, using the industrial grade Ce2(CO3)3 and NH4HCO3 as starting material and precipitating reagent, respectively. The precipitated precursons and the calcinated products were characterized by the thermogravimetric analysis/thermoanalysis (TGA/DTA), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The results show that using NH4HCO3 as a precipitating reagent,the precipitate decomposed full as it was heated to 360℃. The CeO2 superfine powder formed by calcinating the precipitate belongs to a cubic CaF2-type structure and has the first mean particle diameter 140nm and second mean particle diameter 630nm. The CeO2 powder particles aggregate and grow with raising the calcination temperature.  相似文献   

19.
Differences in diagnostic criteria for Sj?gren's Syndrome (SS) have led to confusion in the research literature and in clinical practice. A particular challenge is the clinical diagnosis of the patients with sicca symptoms, fibromyalgia, chronic fatigue, vague cognitive defects, and a low titer antinuclear antibody. Until recently, many of these patients would have been classified as primary SS using the European criteria. A suggested revision of the European criteria will require inclusion of anti SS-A antibody or characteristic minor salivary gland biopsy, leading to greater agreement between European and San Diego criteria. Recent studies have emphasized that lacrimal and salivary gland flow involves an entire "functional" unit that includes the mucosal surface (the site of inflammation), efferent nerve signals sent to the midbrain (lacrimatory and salvatory nucleus), efferent neural signals from the brain, and acinal/ductal structures in the gland. Thus, symptoms of dryness or pain can result from interferences with any part of this functional unit. The initiating antigens in SS remain unknown, but immune reactivity against SS-A, SS-B, fodrin, alpha- amylase, and carbonic anhydrase have been demonstrated in patients with established disease. The inflammatory process in the gland releases metalloproteinases that alter the relationship of epithelial cells to their matrix, an interaction that is necessary for glandular function and survival. Therapies for SS remain inadequate. In SS patients with immune-mediated extraglandular manifestation (ie, lung, kidney, skin, nerve), the therapeutic approach is similar to systemic lupus erythematosus, although these therapies have relatively little effect on tear or saliva flow.  相似文献   

20.
Hybrid density functional theory was used to investigate the structural,electronic,magnetic and elastic properties of the Laves phase binary intermetallics RFe2(R=La,Ce,Pr and Nd) in C15 crystal structure.The calculated lattice constants of these materials are found in good agreement with the experiments.The band structures and density of states distribution confirm the metallic nature of all these intermetallics.The optimized energies in different magnetic phases and magne...  相似文献   

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