R.K.MISHRA
,
P.C.ROUT
,
K.SARANGI
,
K.C.NATHSARMA
中国有色金属学报(英文版)
doi:10.1016/S1003-6326(16)64119-5
在煤油中采用TOPS-99和Cyanex 272钠盐从镍红土矿细菌浸出液中提取与分离锌、锰、钴和镍.采用沉淀法去除不需要的金属离子,使用溶剂萃取提取/分离锌、锰、钴和镍.生物浸出铬铁矿表土样品得到的镍红土矿浸出液中含有3.72 g/L Fe,2.08 g/L Al,0.44 g/L Ni,0.02 g/L Co,0.13 g/LMn,0.14 g/L Zn和0.22 g/L Cr.在pH4时采用CaCO3沉积去除100％ Fe,96.98％ Al和70.42％ Cr,随后在pH 5.4时采用50％氨沉积,溶液中剩有Al和Cr.沉积后,采用0.1 mol/L TOPS-99从无铁、铝和铬的浸出液中提取锌,随后采用0.04 mol/L NaTOPS-99提取锰.锌和锰的产率分别是97.77％和95.63％.提取锰后,再采用0.0125 mol/L NaCyanex 272从浸取液去除钴,最后采用0.12 mol/L NaTOPS-99提取镍,其产率达99.84％.采用稀硫酸去除浸出液中的有机相.
关键词:
镍红土矿
,
锰
,
镍
,
TOPS-99
,
Cyanex 272
Communications in Theoretical Physics
By means of both a theory for pressure-induced shifts (PS) of energy spectra and a theory for shifts of energy spectra due to electron-phonon interaction (EPI), the 'pure electronic' PS and the PS due to EPI of R-1 line, R-2 line, and U band of GSGG:Cr3+ at 300 K have been calculated, respectively. The calculated results are in good agreement with all the experimental data. Their physical origins have also been explained. It is found that the mixing-of degree \t(2)(2)(T-3(1))e(4)T(2)> and \t(2)(3) 2E> base-wavefunctions in the wavefunctions of R-1 level of GSGG:Cr3+ at 300 K is remarkable under normal pressure, and the mixing-degree rapidly decreases with increasing pressure. The change of the mixing-degree with pressure plays a key role not only for the 'pure electronic' PS of R-1 line and R-2 line but also the PS of R-1 line and R-2 line due to EPI. The pressure-dependent behaviors of the 'pure electronic' PS of R-1 line (or R-2 line) and the PS Of R-1 line (or R-2 line) due to EPI are quite different. It is the combined effect of them that gives rise to the total PS of R-1 line (or R-2 line). In the range of about 15 kbar similar to 45 kbar, the mergence and/or order-reversal between t(2)(2)(T-3(1))e(4)T(2) levels and t(2)(32)T(1) levels take place, which cause the fluctuation of the rate of PS for t(2)(2)(T-3(1))e(4)T(2) (or t(2)(3) T-2(1)) with pressure. At 300 K, both the temperature-dependent contribution to R-1 line (or R-2 line or U band) from EPI and the temperature-independent one are important.
关键词:
high-pressure effect;spin-orbit interaction;electron-phonon;interaction;d orbital;coupling between t(2)(2)(3T(1))e(4)T(2) and;t(2)(32)E;tunable laser crystal;theoretical calculations;temperature-dependence;thermal broadenings;garnet crystals;cr3+ ions;r-line;cr-3+;luminescence;ruby;spectroscopy
Communications in Theoretical Physics
By means of both a theory for pressure-induced shifts (PS) of energy spectra and a theory for shifts of energy spectra due to electron-phonon interaction (EPI), the "pure electronic" PS and the PS due to EPI of R-1 line of GSGG:Cr3+ at 70 K have been calculated, respectively. Their physical origins have been revealed. It is found that the admixture of \t(2)(2)(T-3(1))e(4)T(2)) and \t(2)(32) E) base-wavefunctions in the wavefunctions of R-1 level of GSGG: Cr3+ at 70 K is remarkable under the normal pressure, and the degree of the admixture rapidly decreases with increasing pressure. The change of the degree of the admixture with the pressure plays a key role for not only the pure electronic PS of R-1 line but also the PS of R-1 line due to EPI. The detailed calculations and analyses show that the pressure-dependent behaviors of the pure electronic PS of R, line and the PS of R-1 line due to EPI are quite different. It is the combined effect of them that gives rise to the total PS of R, line, which has satisfactorily explained the experimental data (including a reversal of PS of R-1 line). In contributions to PS of R-1 line due to EPI at 70 K, the temperature-independent contribution is much larger than the temperature-dependent contribution. The former results from the interaction between the zero-point vibration of the lattice and localized electronic state.
关键词:
high-pressure effect;spin-orbit interaction;electron-phonon;interaction;d orbital;coupling between t(2)(2)(T-3(1))e(4)T(2) and;t(2)(3)(2)E;tunable laser crystal;temperature
刘欢
,
严凯
,
晏井利
,
薛烽
,
孙甲鹏
,
江静华
,
马爱斌
中国有色金属学报(英文版)
doi:10.1016/S1003-6326(17)60007-4
为了揭示14H相的形成机理，制备并研究了18R LPSO单相Mg?Y?Zn(简称S18)合金经773 K退火100 h的显微组织演变。结果表明：铸态S18合金主要由18R相组成(其体积分数高于93%)，并含有少量的W相和α-Mg相。退火时，S18合金中的18R相保持稳定，未转变成14H LPSO结构。然而，在α-Mg相内部形成了14H层片相，其尺寸和体积分数随着退火时间的延长不断增大。TEM分析表明，14H相在α-Mg内基面堆垛层错区域独立形核。14H层片的增厚生长是界面控制过程，与基面台阶的形成密切联系。而14H层片的伸长生长属于扩散控制，与溶质元素的扩散有关。该18R单相合金中14H相的形成机理可通过反应式α-Mg'→α-Mg +14H表示。
关键词:
Mg-Y-Zn合金
,
18R LPSO相
,
14H LPSO相
,
高温退火
,
显微组织演变
Transactions of Nonferrous Metals Society of China
Phase equilibria of the R-Fe-Co pseudoternary system with R less than or equal to 33.3% ( mole fraction, R = Sm0.5Dy0.5) were determined in an isothermal section at 1073 K and a vertical section of RFe2-RCo2 by using OM, X-ray diffractometer, EP-MA DTA techniques. There are seven intermetallic phases: (Sm, Dy) (Fe, Co)(2), (Sm, Dy) (Fe, Co)(3), (Sm, Dy)(6) (Fe, Co)(23), (Sm, Dy)(2) (Fe, Co)(7), (Sm, Dy) (Fe, Co)(5), Th2Ni17-type and Th2Zn17-type (Sm, Dy)(2)(Fe, Co)(17). The (Sm, Dy)(6)(Fe, Co)(23) phase dissolves 36% Co(mole fraction) at 1073 K. However, the (Sm, Dy)(2)(Fe, Co)(7) phase in R-2(Fe1-xCox)(7) alloys dissolves about 19% Fe(mole fraction) at 1073 K.
关键词:
rare earth-iron-cobalt;phase diagram;structure;compounds;sm-co;magnetic-properties;binary-system;magnetostriction
Physical Review B
The spin-reorientation transition, magnetic anisotropy, and first-order magnetization process (FOMP) of R2Fe14BNx compounds with R = Pr or Nd have been investigated by ac-susceptibility measurements from 4.2 to 300 K, the singular-point-detection technique in a pulsed-field facility in fields up to 30 T between 4.2 and 500 K and magnetization measurements in the Amsterdam High-Field Installation in fields up to 35 T and 4.2 K. It is observed that, compared to the corresponding R2Fe14B compounds, the anisotropy field, B(a), and the critical field of the FOMP, B(cr), of R2Fe14BNx are dramatically reduced, whereas the spin-reorientation temperature T(SR), of Nd2Fe14BNx is only slightly decreased. These experimental data are analyzed in terms of the crystalline-electric-field interaction combined with the R-Fe exchange interaction.
关键词:
field magnetization measurements;single-crystals;nd2fe14b;transition;nitrides;pr2fe14b;series
Journal of Applied Physics
Samples of R2Fe17C(y)N(x) (R = Y, Sm, Er, Tm) were prepared by arc melting appropriate amount of R, Fe, and C, vacuum annealing at 1373 K and finally annealing at 740 K in nitrogen for 10 h. The magnetic properties of these compounds were investigated by means of ac initial susceptibility, magnetization measurements, and x-ray diffraction. The thermal stability of the nitride phase was studied by differential scanning calorimetry. It was found that, when heated above 600 K, R2Fe17C(y)N(x) irreversibly decomposes N which is irrespective of the carbon concentration and rare-earth element. The Curie temperatures of R2Fe17C(y)N(x) are independent of the carbon concentration and are approximately 400 K higher than those of the corresponding pure R2Fe17 compounds. However, the Curie temperatures cannot be correlated to the composition x of the initial R2Fe17C(y)N(x) compounds at room temperature because some N was lost during the heating to T(c). In the Er and Tm compounds spin reorientation transitions were found, marking the change of the easy magnetization direction from the c axis to the basal plane with increasing temperature. The Tm compounds show an additional magnetic transition at low temperatures (below 40 K). A coexistence of the hexagonal and the rhombohedral structural modifications was found in Er2Fe17C(y)N(x) when y < 1.5, characterized by two different spin reorientation temperatures. The anisotropy fields of Sm2Fe17C(y)N(x) are higher than that of Sm2Fe17N(x). Indications of a magnetic phase transition were found also in Sm2Fe17C0.7N(x) and Sm2Fe17C0.9N(x).
关键词:
magnetocrystalline anisotropy;carbides;alloys
Journal of Applied Physics
Electron-doped perovskite manganite Ca(0.9)R(0.1)MnO(3) (R= La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) polycrystalline samples were prepared and their transport and thermoelectric properties were studied from room temperature to 1000 K. The transport behavior for all the samples is adiabatic small polaron hopping mechanism below 600 K but changes to metallic conductivity at higher temperature. Above 600 K, more 3d electrons of Mn(3+) ions will occupy e(g) orbitals, resulting in the variation in thermoelectric power values. For all the samples, thermoelectric power is only determined by carrier concentration, but resistivity also rests with effective bandwidth. The size matching between Ca(2+) and R(3+) ions together with heavier R(3+) doping can improve thermoelectric performance evidently. Combining these two factors, Ca(0.9)Dy(0.1)MnO(3) and Ca(0.9)Yb(0.1)MnO(3) reach ZT=0.2 at 1000 K, suggesting that they can be efficient high temperature n-type thermoelectric oxide materials. (c) 2008 American Institute of Physics. [DOI: 10.1063/1.3003065]
关键词:
transport-properties;oxide;system;performance;fabrication;antimonides;manganites;ca3co4o9;physics;camno3
