Luminescence study of europium(III) tris(β-diketonato)/phosphonate complexes in chloroform

The extraction of Eu(III) with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltrifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β of the first complexes between tris(β-diketonato)Eu(III) and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu(III) luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu(III), while that in Eu(pta)3PhPO was stronger than EuA3; however, in Eu(tta)3PhPO, it was weaker than Eu(tta)3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu(III) luminescence in the complexes as well as the observation of the extractability of Eu(III) with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu(III) was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu(III) and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu(III). It was not significant whether the donor atoms were N or O.     

Colour Centres and Energy Transfer in BaF_(2-x)Cl_x∶Eu~(2+) Phosphors

Electron trapping materials(ETMs)have shownpromise in optical storage.The doubly or multi rare-earth doped alkaline-earth sulfides are a class of sti m-ulatable phosphors,which are expected to be used inthe field of optical Parallel Boolean operation,erasable and re-writable optical memory[1~3].In addition,BaFX∶Eu2+(X=Cl,Br)phosphor,which exhibits photo-sti mulated luminescence(PSL)and offers an alternative to conventional X-rayi magingtechnology to increase the i mage definition anddec…     

Novel High Rate Lithium Intercalation Cathode Materials

In recent years,energy storage devices with bothhigh energy and high power densities have been vigor-ously developed for an application to electric vehicles(EVs).The battery properties of ca.2kW·kg-1ofpower density and ca.15Wh·kg-1of energy densityare needed for the EV′s application in the future[1].As the electrode materials are basic elements for thebattery device,the cathode electrodes should have su-perior properties to above expected ones.One ap-proachto develop the cathode materials…     

ENERGY TRANSFER FROM PHTHALIC ACID-TERBIUM COMPLEX TO EUROPIUM(Ⅲ)

The intramolecular energy transfer of ortho-phthalic acid-terbium[Tb(phth)_3]and ortho-toluicacid-terbium[Tb(tolu)_3],the intermolecular energy transfer from Tb(phth)_3 to Eu~(3 ) in solution and theirluminescent property have been studied by absorption,Infrared,fluorescence and time-resolved emissionspectroscopic method.The influences of solvents and pH of the media on the emission intensity and thelifetime are discussed as well.     

Microstructures and Electrochemical Properties of Cobalt-Free LaNi_(4.0)Al_(0.2)Fe_(0.4)Cu_(0.4-x)Sn_x (x=0～0.4) Electrode Alloys Prepared by Casting

To decrease the cost of nickel-metal hydride (Ni/MH) batteries ,the replacement of Co in LaNi5-basedmetal hydride electrodes by other alloying elements hasbeen of great interest to many researchers[1 ~5]. Al-though researchers have considerably investigated thepreparation of low-Co ,Co-free hydrogenstorage alloy ,the results are still unsatisfactory[1 ,2].The main prob-lemis that the cycle stabilities of low-Co and Co-freeAB5-type electrode alloys are very poor ;therefore ,therole played b…     

SIMULTANEOUS POLYMERIZATION AND FORMATION OF POLYPHENYLACETYLENE FILMS BY RARE-EARTH COORDINATION CATALYSIS Ⅳ.KINETICS AND MECHANISM OF POLYMERIZATION

The CO_2 quenching method has been used for the first time to determine the active complex concen-tration in Nd(naph)_3-Al(i-Bu)_3 catalyst system for polymerization of phenylacetylene intopolyphenylacetylene(PPA)films.The kinetics and mechanism of this polymerization have been investigatedby CO_2 quenching and IR,UV analytical methods.The kinetic equation can be expressed asRp=k[M][Cp],and the apparent activation energy is about 13.6 kJ/mol.There is self-termination ofchain propagating.Models for formation of the active complex and polymerization mechanism are proposed.     

STRUCTURAL AND MAGNETIC PROPERTIES OF RTiFe_(11),RTiCo_(11) AND RTi(Fe_(1-x)Ni_x)_(11) COMPOUNDS(R=Nd,Sm,Gd,Tb,Dy,Ho,Er AND Y)

The crystallographic structure and intrinsic magnetic properties have been investigated in the RTiFe_(11),RTiCo_(11) and RTi(Fe_(1-X)Ni_X)_(11) compounds,where R represents Nd,Sm,Gd,Tb,Dy,Ho,Er and Y.Neutrondiffraction and Mossbauer spectra analyses have been used to study the nuclear and magnetic structure ofthese compounds.the Fe,Co,Ni and Ti atoms are found to exhibit strong site preference with f and j sites fa-voring Fe,Co and Ni atoms and the i site Ti atoms.Two different types of magnetic behavior were observed inthe RTiFe_(11) and RTiCo_(11) compounds.In the former,the interatomic distance and the number of nearestneighbor atoms play essential roles.In particular,anomalous thermal expansion behavior is presented inRTiFe_(11).In the latter,the magnetic properties are essentially determined by the modification of the cobaltelectronic configuration brought about by the transfer of rare earth conduction electrons to the transition 3dband.The saturation magnetization,Curie temperature and magnetocrystalline anisotropy data of RTiFe_(11),RTiCo_(11)and YTi(Fe_(1-X)Ni_X)_(11)are presented.A tempt to improve the intrinsic magnetic properties inRTiFe_(11)has been made,and the results are reported.On the basis of the crystalline field theory by using asingle-ion model,the anisotropy constants and their temperature dependence of the R ions have been calcu-lated,which helps explain the spin reorientation observed in RTiFe_(11).     

A Study of the Magnetic Properties of Intermetallic Compound RFe_(12-x)M_x

The structure and intrinsic magnetic properties of RFeM(M=V or Ti),type 1:12,have been studied bymagnetic measurement and X-ray diffraction.They are body-centered tetragonal ThMn_(12)structure.Thechanges of crystal lattice constants coincide with that of their element radii.Curie temperature is decided mainlyby the exchange interactions of 3d-3d and 3d-4f atom pairs.The data obtained by mean-field approximationagree well with experimental values.The magnetic moment coupling in these compounds for LRE isferromagnetic,and for HRE is antiferromagnetic.At low temperature,anisotropy field is decided by REsublattice.In this paper,the influence of magnetic properties of cobalt and nickel replacing iron has also beenstudied.     

Thermochemical Properties of the Complexes RE(HSal)_3·2H_2O (RE=La,Ce,Pr,Nd,Sm)

Nowadays great attention has been paid to thelanthanide aromatic carboxylates owing to their novelstructures and potential applications in material sci-ences as superconductors ,magnetic materials ,andlu-minescent probes[1 ~6].The luminescence , mechanismof thermal descomposition , stability constants , andother properties of some lanthanide complexes withsalicylic acid have been reported in literatures[7 ~10].And thermochemistry of other lanthanide complexes hasbeen described[11 ,12]. Thermoc…     

Key technologies of roll forming automobile components with AHSS

Lightweight design is one of the development trends of the automobile industry.An effective way to achieve lightweight auto bodies is to use AHSS (advanced high strength steel) for the safety components of automobiles.This study has taken doorsill reinforcements made of martensite AHSS as the object,and performed research on the AHSS roll forming technologies and prototype development of typical asymmetric open components.By means of finite element analysis (FEA) and simulation,studies have been carried out on the springback and edge wave defects during AHSS roll forming,and an optimized process design has been achieved.The generation mechanisms of vertical bows,horizontal cambers,twists,pre-punched hole distortion and cut end flare have been analyzed,and solutions to these defects have been given.In addition,tesing of the roll forming process for AHSS has been conducted and typical samples with required dimensional accuracy have been manufactured.This study has provided technical support for the large-scale application of AHSS.     

Flow-Injection Enhanced Chemiluminescence Method for Determination of Penicillamine

A new flow-injection procedure has been developed for the determination of penicillamine based on the enhancement of the chemiluminescence (CL) reaction of the penicillamine-cerium (Ⅳ)-hydrocortisone system. The method was simple, selective and sensitive with a detection limit of 6.2×10-5mol·L-1 (S/N=3). It was applicable to the determination of penicillamine in the concentration range of 2×10-6~5×10-4mol·L-1. The method was successfully applied to the determination of penicillamine in tablets. The relative standard deviation (RSD) was 1.42% (n=7) and the recovery was 97%~103% (n=4).     

Blue-Light Emission from Undoped and Rare Earth-Doped Wide Bandgap Oxides

Blue-light emitting materials have been receivingconsiderable attention due to their applications for avariety of optoelectronic devices and display technolo-gies . Rare earth-doped compounds have long founduses as blue phosphors in a variety of devices due totheir intensely luminescent f-d and f-f electronictransitions[1]. Metal sulfides ,such as ZnS have beenutilized as conventional phosphors due to their excel-lent brightness . However ,the life span of the displaydevices is li mited due t…     

Theoretical and Experimental Research on the Rolling Force in Rail Hot Rolling by Universal Mill

 In rail rolling by universal mill, a simplified 3-dimention theoretical model has been built firstly. The kinematically admissible velocity field of the web, head and base of rail have been determined respectively, moreover the corresponding strain rate field and the strength of shear strain rate have been also obtained. Then the plastic deformation power of corresponding deformation zone, the powers consumed on the velocity discontinuity surface and the powers generated for backward slip and forward slip have been proposed. According to the upper-bound method, the roll force of horizontal roll and two vertical rolls can be obtained. Moreover, The process of 18kg/m light rail and 60kg/m heavy rail universal rolling have been simulated by rigid-plastic FEM(finite element method) for verifying the theoretical model. And the universal rolling experiments of 18kg/m light rail has been accomplished in Yanshan University Rolling Laboratory. Compared the results of numerical simulation and the experimental data, the roll force from upper-bound method is somewhat greater than experimental data but in general do not exceed them by 20 percent. So, it is reliable and feasible to preset and optimize the parameter of rolling technology according to the upper-bound method.     

Effect of microelements on microstructures and properties of Al-1. 2Mg-1. 3Si-0. 6Cu-0. 3Mn alloy

In order to save energy and protect environmentin automobile industry, one of the important methodsis to reduce the automotive weight[1 ～4]. Since the a-luminum alloys showsuch as high specific strength,good formability, good corrosion resistance, and re-cycling potential, they are said to be the ideal candi-date to replace heavier materials in the automotiveindustry[5 ～7].Recently, the heat -treatable 6000series aluminum alloys have been considered as theperfect light-weight material for au…     

Precipitation Strengthening by Nanometer-sized Carbides in Hot-rolled Ferritic Steels

The mechanical properties of the hot-rolled plates of Ti steel and Ti-Mo steel after isothermal transformation in a temperature range of 600 700 ℃ for 60 min have been tested, and the microstructures of the matrix and the characteristics of precipitated nanometer-sized carbides have also been examined by scanning electron microscopy and transmission electron microscopy. The precipitation regularity of nanometer-sized carbides has been studied by thermodynamic method and the contributions of corresponding strengthening mechanisms to the total yield strength have been calculated. The tensile strength of hot-rolled Ti-Mo ferritie steel can achieve 780 MPa with an elongation of 20.0% after being isothermally treated at 600 ℃ for 60 rain, and the tensile strength of Ti steel is 605 MPa with an elongation of 22.7%, according to the results of tensile tests. The critical nucleation size of （Ti,Mo）C is smaller than that of TiC at a given isothermal temperature, but the nucleation rate of （Ti, Mo）C is larger than that of TiC. The grainrefinement strengthening and precipitation strengthening contribute the main amount of the total yield strength. The major increase in yield strength with the decrease of isothermal temperature results from the contribution of precipi tation strengthening. The contribution of precipitation strengthening to the yield strength of the steels has been esti mated. The ferrite phase can be strengthened by about 400 MPa through precipitation strengthening in Ti-Mo steel isothermally treated at 600 ℃ for 60 rain, which is about 200 MPa higher than that of Ti steel under the same conditions.     

ABSTRACTS——From Journal of Iron and Steel Research (in Chinese) 2006,18(5)—2006,18(6)

Phase Division of Development History for EAF Steel-making Technology FU Jie ( School of Metallurgical and Ecological ,University of Science and Technology Beijing,Beijing100083 , China)Abstract :The 5 characteristics of the development history ofthe modern EAF steel making technology have been proposed .The phase division of development history of the EAF steel-making technology was discussed . Four phases including theadvent and the development ,and the maturity of the tradition-a…     

CHARACTERISTIC CURVES OF M-H AND COEXISTENCE OF MAGNETISM WITH SUPERCONDUCTIVITY FOR HIGH T_c SUPERCONDUCTORS REBa_2Cu_3OT_(7-x)

Some high T_c superconductors REBa_2Cu_3O_(7-x)(RE=Sm,Eu,Gd,Dy,Ho,Er,Tm) with zero resist-ance temperatures were about 90K have been prepared.The effect of magnetic rare earth ions on the transi-tion temperatures is not very great,but their magnetic behaviours are different from each other.Themagnetization loops of these compounds have been measured at 77K.The coexistence of superconductivitywith magnetic ordering (COSM) found in the samples with RE=Gd,Dy,Ho,Er,Tm,indicates that thereare two possible ways of coexistence in the samples.These expertments show that the relation ofparamagnetism to the atomtc number of rare earth elements for these superconductors is similar to that ofrare earth ions in some paramagnetic salt crystals,which indicates that the magnetism of the samples origi-nates from the local magnetic moments of rare earth ions.In some samples there is antiferromagnetie orderingat low temperatures,and the effective Bohr magneton numbers are consistent with that of free rare earth ions.Some superconducting parameters including the critical current density are calculated according toGinzburg-Landau theory and the critical state model.     

Strain Limit of Extra Galvannealed InterstitialFree and Bake Hardened Steel Sheets Under Different Stress Conditions

The formability of bake hardened steel （thickness 0.82 mm）, and the extra galvannealed IF steel （thickness 0.82 mm） have been studied. The suitability of the above steels for forming applications has been critically examined. The microstructure, tensile properties, and formability parameters of the above sheet metals were determined. The manufacturing process of the steels and the significance with reference to its formability were studied.     

Growth and Optical Spectra of Zn∶Er∶LiNbO_3 Crystals Using Bridgman Method

The lithiumniobate single crystal (LiNbO3,LN)is one of the most i mportant materials because of itsexcellent properties such as piezoelectricity , photo-electricity, photorefractivity , and a nonlinear opticaleffect .It has been widely used for functional applica-tions such as , in the surface acoustic wave device(SAW) ,the piezoelectric transducer (PET) ,the op-tic parameter oscillator ( OPO) , the high-resolutionholographic storage and so on[1]. The Er3 +dopedLiNbO3crystals have also …     

Radiant Image Simulation of Pulverized Coal Combustion in Blast Furnace Raceway

The numerical si mulation of combustion processhas been performed[1,2],but thereis still no suitabletemperature measuring technique for three-di men-sional analysis[3].Nowadays,the radiant i mage pro-cessing technique has been developed at home and a-broad[4,5].The relation between radiant i mage andpulverized coal combustion process in blast furnaceraceway was studiedin present work withthis meth-od to examine three-di mensional temperature distri-butionin blast furnace raceway.1Radiant Image…