Thermal and radiative characteristics of oxyfluoride glass singly doped with lanthanide ions

Rare earths-doped oxyfluoride glasses based on germanium oxide and lead fluoride were prepared from commercial raw materials. The glasses with general composition of 50GeO2-(50-x-y)PbO-yPbF2-xLnF3 (Ln=Pr3+-Yb3+), contained different concentrations of optically active dopants (x=0.2 mol.% and 2 mol.%) and PbF2 (y≤15 mol.%). The differential thermal analysis (DTA) was used to determine both thermal characteristic and thermal stability properties of the glasses in the function of the kind of dopant, its concentration, and a glass composition. Characteristic glass temperatures such as glass transition temperature (Tg), glass crystallization temperature (Tc) and temperature corresponding to the maximum of the crystallization rate (Tpc) were evaluated. On the basis of obtained results, the thermal stabilities of glasses under study were evaluated using various thermal stability criteria (Dietzel factor ?T, Saad-Poulain factors H' and S). It was found that the increase in rare earth fluoride contents influenced thermal characteristics when the characteristic temperatures of the individual glass was shifted towards higher values. The effect of the PbF2 content and the kind of rare earth impurity on the glass stability was observed. Absorption spectra of lanthanide-doped glasses were measured at room temperature and used to determine the phenomenological intensity parameters Ωt and next, to estimate radiative properties of lanthanide ions in this matrix. Radiative transition probabilities of luminescent states of Ln3+, branching ratios and radiative lifetimes were determined. The variation of the Ωt along the lanthanide series was presented and discussed.     

Process optimization of electroless copper plating and its influence on electrochemical properties of AB5-type hydrogen storage alloy

The amount of Cu coating by chemical plating was investigated based on quadratic regression orthogonal experimental design being adapted to the variation law of temperature,pH value and Ni2+concentration,and the relevant regression equation was expressed as y=2.1609+0.5295×10-3T2-0.0342P2-0.0265N2+0.0023TP+0.0020TH+0.0199PN-0.0959T+0.3814P-0.2073N.The results showed that the deposition rate augmented with the increasing in temperature,pH value and Ni2+concentration.The experimental parameters of the optimal coating were temperature 75 ℃,pH value 8.5 and Ni2+concentration 1.2 g/L.The electrochemical tests indicated that the cycle stability increased from 60.66% to 75.58%,indicating that the treated alloy exhibited better corrosion resistance.     

Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

天铁热力风机升级改造方案设计

通过对天铁集团高炉现状、风机现状的分析,提出了对热力厂风机升级改造的规划,确定了实施方案.该方案实施后将彻底改变风机渐进式改造的现象,使新高炉的备用机组发挥更大的作用,可增加现有高炉的风压、风量,使现有高炉的产量、冶炼强度进一步提高.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

Recent progress report on DNA B-Z transition modulated by rare earth-amino acid complex and Alzheimer's disease amyloid beta

Rare earth dements have unique physical, magnetic, luminescent and catalytic properties. They have been successfully used as medicine and probes in luminescent resonance energy transfer (LRET) for bioassays, as well as reagents for diagnosis in magnetic resonance imaging (MRI). In this progress report, we will focus on recent progress on how rare earth amino complexes bind to DNA and change DNA structure, especially on DNA B-Z transition induced by rare earth amino acid complex and its potential impact on Alzheimer's disease (AD).     

Numerical Simulation on Inclusion and Bubble Entrapment in Solidified Shell in Model Experiment and in Mold of Continuous Caster With DC Magnetic Field

A model experiment investigating entrapment of inclusions and bubbles on the solidified shell was performed using molten steel,and the conditions for inclusion and bubble entrapment and mechanism of entrapment were studied.The results were applied to the flow behavior in the casting mold of a continuous caster.At the solid-liquid interface,entrapment of inclusions is greatly reduced by the existence of a low velocity flow,e.g.,0.05m/s.The above-mentioned interfacial flow velocity dependency of inclusion entrapment is considered to be largely influenced by changes in the thickness of the concentration boundary layer,which depend on the interfacial flow velocity.Specifically,bubbles and inclusions which enter the concentration boundary layer are drawn to the solid-liquid interface by a suction force which is several orders larger than the Saffman’s force.In addition to the above-mentioned suction force,the so-called cleaning effect is determined by fluid-dynamic forces such as drag force,etc.which act on particles,and furthermore,by resident time of particles at the solid-liquid interface,which depends on the solidification rate.In a FC mold with a 2-stage electromagnetic brake,flotation of bubbles entrained in the jet flow from the nozzle is accelerated with the large DC magnetic field.This is attributed to the braking effect of the DC field on the nozzle jet and the upward flow by the buoyancy of the bubbles.As a result,the interfacial flow velocity can be normalized by increasing the strength of the magnetic field,and entrapment of large bubbles and inclusions can be reduced.     

Some corrections of coccidian (Apicomplexa: Protozoa) nomenclature

The following nomenclatural corrections and changes are introduced for the coccidia. NEW SPECIES: Cryptosporidium rhesi from the rhesus monkey Macaca mulatta; Cryptosporidium serpentis from the snakes Elaphe guttata, Elapha subocularis, Crotalus horridus, and Sanzinia madagascarensis; Eimeria perazae from the lizard Cnemidophorus l. lemniscatus; and Eimeria tarichae from the salamander Taricha toirosa. NEW COMBINATIONS: Orcheobius carinii for Cariniella carinii from the frog Leptodactylus ocellatus; Schellackia iguanae for Lainsonia iguanae from the iguana Iguana iguana; Schellackia weinbergi for Haemogregarina weinbergi from the lizard Tupinambis nigropunctatus; Dorisa harpia for Dorisiella harpia from the bat Harpiocephalus harpia lasyurus; Barrouxia labbei for Echinospora labbei from the centipedes Lithobius mutabilis and L. pyrenaicus; and Barrouxia ventricosa for Echinospora ventricosa from the centipede Lithobius hexodus. The generic names Lainsonia and Gordonella are synonymized with Schellackia; Echinospora with Barrouxia; and Cariniella with Orcheobius.     

Reduction of CO2 Emissions from Steel Plants by Using Steelmaking Slags for Production of Marketable Calcium Carbonate

By carbon dioxide mineralization, CO₂ can be stored safely and leakage‐free for very long times. Owing to their high calcium content, steelmaking slags are suitable for mineral carbonation. In a country like Finland, where no suitable geological formations for CO₂ storage seem to exist, steelmaking slag carbonation offers an important CO₂ emissions reduction option for steel plants. If calcium could be extracted selectively from the slags prior to carbonation, a pure, and possibly marketable, calcium carbonate may be produced. This could replace some of the natural and synthetic CaCO₃ used in industry, combining savings in natural resources with CO₂ emissions reduction. Development work on the production of pure calcium carbonate from steelmaking slags by carbonation is presented in this study. Selective extraction of calcium from steelmaking slags was investigated using various solvents. Precipitation of CaCO₃ from dissolved calcium at atmospheric pressure was also investigated. Amongst the various tested solvents ammonium salt solutions (NH₄Cl, CH₃COONH₄, NH₄NO₃) were found to be the most promising for selectively extracting calcium from steel converter slag. These solvents dissolved calcium efficiently also from desulphurization slag, while extraction of calcium from two other types of slag was poor. CaCO₃ was successfully precipitated from the solution containing ammonium salt and dissolved steel converter slag.     

Phase equilibria of the VS-V5S8 system from 923 to 1323 K

Sulfur partial pressure-isotherms at temperatures from 923 to 1323 K were obtained over a wide range of compositions of VS-V₅S₈ by combining results from the phase equilibria of the VS-V₃S₄ system in the present study and those from previously reported ones for the V₃S₄-V₅S₈ system at temperatures from 923 to 1173 K. The phase equilibria of VS-V₃S₄ were determined for the composition range from VS_1.08 to VS_1.333 by the quenching method under controlled partial pressure of sulfur in the range from 10¹⁴ to 10 ⁻³ atm (1 atm = 101.3 kPa) at temperatures from 1023 to 1323 K. Three vanadium sulfides were observed for this composition range in agreement with results reported in the literature,i.e. orthorhombic VS, hexagonal VS, and V₃S₄. The quenched V₃S₄ phase with nonstoichiometric composition extended over both metal-rich and sulfur-rich regions of the plateau, supposedly representing a two phase region, observed on each Ps₂-composition isotherm. This anomalous phase relation was discussed along with the profiles of the isotherms. The partial molar enthalpies of sulfur in the nonstoichiometric hexagonal VS and V₃S₄ regions were calculated from the isotherms. Their values ranged from −46 to −56 kcal/g-at. (from −190 to −240 kJ/g-at.) and decreased with increasing deviation from stoichiometry.     

Rapports annuels.

Presents annual reports (1985) from the Canadian Psychological Association, including reports from the Constitution and By-Laws Committee; the Continuing Education Committee; the Convention Committee; the Elections Committee; the Committee on Ethics; the Committee on Fellows and Honorary President; the International Relations Committee; the Nominating Committee; the Professional Affairs Committee; the Publications Committee; the Scientific Affairs Committee; the Committee on Sections; and the Committee on the Status of Women. Sections reports are also provided, including reports from the sections on Brain and Behaviour; Community Psychology; Educational Psychology; Health Psychology; Industrial/Organizational Psychology; Programme Evaluation; Psychology and Religion; Psychopharmacology; Social Psychology; and Women and Psychology. The sections reports are followed by division reports, including reports from the Applied Division and the Experimental Division. Journal reports are then presented, including reports from Canadian Psychology; Canadian Journal of Psychology; and Canadian Journal of Behavioral Science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Annual reports.

Presents annual reports (1985) from the Canadian Psychological Association, including reports from the Constitution and By-Laws Committee; the Continuing Education Committee; the Convention Committee; the Elections Committee; the Committee on Ethics; the Committee on Fellows and Honorary President; the International Relations Committee; the Nominating Committee; the Professional Affairs Committee; the Publications Committee; the Scientific Affairs Committee; the Committee on Sections; and the Committee on the Status of Women. Sections reports are also provided, including reports from the sections on Brain and Behaviour; Community Psychology; Educational Psychology; Health Psychology; Industrial/Organizational Psychology; Programme Evaluation; Psychology and Religion; Psychopharmacology; Social Psychology; and Women and Psychology. The sections reports are followed by division reports, including reports from the Applied Division and the Experimental Division. Journal reports are then presented, including reports from Canadian Psychology; Canadian Journal of Psychology; and Canadian Journal of Behavioral Science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrafine and nanoscaled tungsten carbide synthesis from colloidal carbon coated nano tungsten precursor

Abstract

A new process for synthesising homogeneous ultrafine and nanoscaled tungsten carbide with good stability in air from well dispersed colloidal carbon coated nano tungsten precursor with highly agglomerated nanoscaled tungsten powder as starting material in a cost effective way is introduced. It is shown that hydrogen atmosphere facilitates the carbon and tungsten reaction process. Inheritance character in grain size distribution of tungsten carbide from tungsten starting material with BET calculated grain size of 46·1 nm has been observed. When the carburisation temperature increases from 1000 to 1300°C, the Brunauer–Emmett–Teller calculated grain size of tungsten carbide powder increases from 68·6 nm to 339·4 nm and the oxygen content decreases from 0·44 to 0·10%.     

亚硫酸钠在稀贵金属冶金中的应用

系统总结了亚硫酸钠在稀贵金属冶金中的应用。主要阐述了从铜镍合金氯化渣中脱硫富集贵金属,从铜阳极泥分金渣中分银,从高硒、碲的铜阳极泥中分离回收金、钯、铂,硒、碲的分离提纯,在盐酸介质中还原精炼金,从负载有机相中反萃金,从弱酸性介质中还原银,制备金的电镀配合物等,以期为从事相关领域的科技人员提供参考。     

Production of powders of cast iron shavings and special features of production of components from these powders. III. Structure and strength of heat-treated alloys

Conclusions Quenching the specimens from 800°C does not lead to the redistribution of the carbide in the volume of the alloys of the iron-cast iron system. The most homogeneous structure of the alloys is formed only in quenching from 900°C. However, quenching from 1000°C increases the size of voids and causes supinating of the alloys, although their homogeneity increases.Heat treatment increases the tensile strength of the alloys which contain 10–50% of low-alloy cast iron. The alloys quenched from 800°C have the maximum strength after tempering of 300°C, whereas the alloys quenched from 900 and 1000°C with a maximum strength at tempering temperatures of 250 and 200°C, respectively.The highest hardness was recorded for the alloys after quenching from 900°C. All the alloys quenched from 800, 900, and 1000°C are characterized by sufficiently higher hardenability to a depth of 4mm.An increase of the tempering temperature of the alloys in the range 200–300°C reduces their impact toughness. This fact is not in agreement with the generally recognized interpretations. However, an increase of the cast iron content usually greatly reduces the KC value of the specimens, regardless of the quenching and tempering temperatures.Translated from Poroshkovaya Metallurgiya, No. 1(325), pp. 47–53, January, 1990.     

Removal of chromium(III) by cation exchange resin, Indion 790 for tannery waste treatment

Extraction of chromium(III) from a model solution and from a tannery waste solution was studied by ion exchange using Indion 790 resin which is a macro-porous strongly acidic cation exchange resin of sulfonated polystyrene group. The resin was found to be selective for the sorption of chromium(III) in the pH range 0.5–3.5 from a model solution containing 500 ppm Cr(III). Beyond pH 3.5 extraction of chromium(III) drastically decreased from 92% to 76%. Sorption of chromium(III) on Indion 790 followed the Freundlich isotherm with a high Freundlich constant value (K_f = 8.57) confirming strong chemical interaction of the metal ion with the resin. Desorption of chromium(III) from the loaded resin increased with the increase in concentration of eluant (5–20% H₂SO₄). With 20% sulfuric acid solution 89% Cr(III) was eluted in two stages. The bench scale results were also validated in continuous mode in a fixed bed column and for the recovery of chromium(III) from a tannery solution.     

Adsorption-chemical activity and interaction in the boron nitride-titanium hydride system

The paper examines the effect of physicochemical properties of starting boron nitride and titanium hydride on their reactive activity in the synthesis of the TiN-TiB_x composite. There are kinetic data on thermal desorption of the active adsorbate from the BN surface, which precipitated from the gas mixture (20 vol.% O₂-80 vol.% N₂ under the relative humidity of 80%). Kinetics of hydrogen release from titanium hydride in isothermal conditions and controlled rate of temperature increase in the reactive system is researched. A possible mechanism of chemical transformations of starting compounds and synthesis of the TiN-TiB_x composite is considered. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 102–110, 2007.