Magnetocaloric effect and magnetic properties of La_（0.9）Ce_（0.1）（Fe_（0.99）Mn_（0.01））_（11.6）Si_（1.4）H_（1.6） compound

Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.     

Sintering of Ce（0.8）Sm（0.2）O（1.9）

Ce0.8Sm0.2O1.9（SDC）powder was prepared with an oxalate coprecipitation route.SDC solid solutions were sintered at various temperatures ranging from 1100~1450 ℃,and characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,density measurements,and electrical conductivity measurements.The optimized processing parameters for densification were to uniaxially press the sample at 200~400 MPa and sinter it at 1350~1400 ℃ for 4 h.The density of the sintered pellets was 〉90% of the theoretical density;their soakage was 〈0.5%;and the average grain size was 1~2 μm.The conductivities of the typical sintered specimen were 0.0133 and 0.0211 S·cm-1 at 550 and 600 ℃,respectively;Its activation energy for ionic conductivity was 0.62 eV.The dense SDC bulk material could be used as the electrolyte layer of low temperature solid oxide fuel cells.     

HPBI对镧（Ⅲ）,铈（Ⅲ）,铕（Ⅲ）,钍（Ⅳ）,铀（Ⅵ）的溶剂萃取行为

本工作研究了HPBI~a(以氯仿为稀释剂)对La(Ⅲ)、Ce(Ⅲ)、Eu(Ⅲ)、Th(Ⅳ)、U(Ⅵ)的萃取行为。探讨了萃取机理和几种萃取类型。计算了每种体系的萃取常数。该体系已用于从U(Ⅵ)中分离Th(Ⅳ)及从La(Ⅲ)、Ce(Ⅲ)、Eu(Ⅲ)中分离Th(Ⅳ)。比较了HPBI、HPMBP~b、HTTA的萃取常数,结果表明HPBI萃取上述几种金属要优于HPMBP和HTTA     

A study on hydrogen storage and electrochemical properties of La_（0.55）Pr_（0.05）Nd_（0.15）Mg_（0.25）Ni_（3.5） （Co_（0.5）Al_（0.5））_x （x=0.0, 0.1, 0.3, 0.5） alloys

The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)x(x=0.0, 0.1, 0.3, 0.5) alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases, and the cell volumes of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 (x=0) to 1.47 wt.% (x=0.3) and then decreased to 1.22 wt.% (x=0.5). The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)0.3 alloy electrode possessed better electrochemical kinetic characteristic.     

Structure and high-temperature electrochemical properties of La_（0.60）Nd_（0.15）Mg_（0.25）Ni_（3.3）Si_（0.10） hydrogen storage alloys

The structure and high-temperature electrochemical properties of the as-cast and annealed (940 °C, 8 h) La0.60Nd0.15Mg0.25Ni3.3Si0.10 hydrogen storage alloys were investigated. The X-ray diffraction revealed that the multiphase structure of the as-cast alloy with LaNi5 phase as the main phase was converted into a double-phase structure with La2Ni7 phase as the main phase after annealing. The surface morphology studied by scanning electronic microscope (SEM) showed that the annealed alloy had a much higher anti-corrosion ability than the as-cast alloy. Both alloys presented excellent activation characteristics at all test temperatures. The maximum discharge capacity of the as-cast alloy decreased when the test temperature increased, while the temperature almost had no effect on the annealed alloy. As the test temperature increased, the cyclic stability and charge retention of both alloys decreased, and these properties were improved significantly by annealing.     

Stable icosahedral phase in Mg_（44）Zn_（44）Gd_（12） alloy

The microstructure of the as-cast Mg 44 Zn 44 Gd 12 alloy was investigated by using X-ray diffraction(XRD),differentical scanning(DSC),scanning electron microscopy(SEM) and a detailed transmission electron microscope.The XRD,DSC and SEM results indicated that the as-cast Mg 44 Zn 44 Gd 12 alloy were mainly composed of three types of phases:the primary solidification phase,the dendritic phase and the eutectic phase.The primary solidification phase had an icosahedral structure.The dendritic phase was the W-phase,and eutectic structure phase was the Mg 7 Zn 3 phase.Microstructures of icosahedral phase(I-phase),W-phase and Mg 7 Zn 3 phase in Mg 44 Zn 44 Gd 12 alloy were investigated.The results indicated that the I-phase in Mg 44 Zn 44 Gd 12 alloy was a face-centered icosahedral quasicrystal with stoichiometric composition of Mg 42 Zn 50 Gd 8 which had an excellent thermal stability up to 420 °C.The solid solution of the Gd gradually decreased during solidification,which played an important role in activating the formation of Mg 7 Zn 3 phase and W-phase from icosahedral phases.     

P_（507）（煤油）／（Sm－Eu－Gd）Cl_3（EuCl_2）－HCl体

本文在选定的工艺条件下，在振动筛板柱中研究了Ｐ（５０７）（煤油）／（Ｓｍ－Ｅｕ－Ｇｄ）Ｃｌ３（ＥｕＣｌ２）－ＨＣｌ体系的两相流动特性和传质特性。结果表明，该体系在振动柱中有良好的流动特性。在流比２．５～４．０，振幅＝１０ｍｍ，频率＝３００～３５０ｍｉｎ（－１）条件下，两相总液泛通量达２２０Ｌ／ｄｍ２·ｈ，存留分数一般为１２～１５％。用分段近似计算法，估算了柱子的传质效率。对于较难萃取的组分Ｓｍ，平均传质单元高度为０．５２ｍ，平均理论级当量高度为１．８２ｍ。     

用二烷基－（二芳基）［二乙基氨基甲酰甲基］氧化磷从高氯酸和某些酸的混合物中萃取 镅（Am）（Ⅲ）、铕（Eu）（Ⅲ）和铀（U）（Ⅵ）

本专题研究了用二烷基－（二芳基）〔二乙基氨基甲酞甲基〕氧化磷（ＣＭＰＯ）从高氯酸溶液中萃取锯（Ⅲ）、铕（Ⅲ）和铀（Ⅵ）。试验表明，在萃取上述元素时，从高氯酸溶液中萃取比从硝酸溶液中萃取更为有效。在高氯酸介质中，“异常芳基效应”比在硝酸介质中更为显著。在高氯酸介质中，上述元素的溶剂化数也会增加。当采用芳基取代的萃取剂时，溶剂化数极高，但是，在采用烷基取代的化合物时，则不会达到同样高的数值。试验表明，在硝酸和高氯酸溶液中，“异常芳基效应”的值直接取决于芳基和烷基取代的ＣＭＰＯ络合物中元素溶剂化数值之差。事实上，在磷酸和硫酸中，镅（Ⅲ）、铕（Ⅲ）和铀（Ⅵ）并不被ＣＭＰＯ溶液萃取。本专题还研究了从不同的酸溶液中萃取元素时，高氯酸浓度对其萃取率的影响。试验发现。在某些情况下，分配系数显著增大，协同效应也相应增加。本方法通过增加少量的高氯酸即可提高元素的萃取率，因此可以推荐用于从硝酸、磷酸和硫酸中萃取和预浓缩镅（Ⅲ）和铀（Ⅵ）。