The nature of particles yielded during electron-stimulated desorption of samarium from oxidized tungsten surface

It is established for the first time that the yield resonances related to excitation of the core electron levels of samarium (Sm) and tungsten (W) during the electron-stimulated desorption of samarium from the surface of oxidized tungsten represent neutral particles differing in the chemical nature. Most probably, the excitation of samarium levels leads to desorption of Sm atoms, while the excitation of tungsten levels causes desorption of SmO molecules.     

Oxidation of a thin samarium film on iridium

Thermal desorption spectroscopy has been used to study the interaction of oxygen with a thin (<1 nm) samarium film deposited onto a textured iridium ribbon. Desorption of Sm atoms from Ir surface takes place from various states (chemisorbed, condensed, from compound with iridium, and oxide). The formation of samarium oxide is observed already at room temperature. As the temperature increases to T = 1100 K, a compound of samarium with iridium is formed at the first stage and then oxygen interacts with Sm atoms from this compound and “slow” (compared to the first process) growth of samarium oxide takes place.     

Use of doubly charged ions in the determination of certain rare earth elements in neodymium, samarium, europium, and their compounds by inductively coupled plasma mass spectrometry

It is proposed to use doubly charged ions of the rare earth elements (REEs) to be determined in samples of neodymium, samarium, europium, and gadolinium by inductively coupled plasma mass spectrometry (ICP-MS) in order to reduce spectral interferences caused by oxide and hydroxide matrix ions. Optimal conditions for the registration of the doubly charged ions of REEs (resolution, depth of plasma sampling, generator output power, and argon flow in a nebulizer) are developed. The limits of determination for the REEs determined using singly and doubly charged ions in the samples of Nd, Sm, Eu, and Gd are evaluated. It is shown that the use of the signal from the doubly charged ions of odd isotopes allows reducing the limits of determination for Dy, Ho, Tm, and Er in neodymium, samarium, europium, and their oxides by one to two orders of magnitude.     

含 Sm 聚合物的制备及荧光性质

用 Sm_2O_3制备了甲基丙烯酸钐和辛酸钐。通过添加或交联制得了含 Sm 的甲基丙烯酸和甲基丙烯酸甲酯共聚物。测定了 Sm 盐的元素分析、IR、TG、DTA 和它们在溶液中的荧光性质。研究了含 Sm聚合物的力学性能和荧光性质。     

Sm_2O_3/EPDM复合材料的硫化特性及力学性能

文中研究了Sm2O3/EPDM复合材料的硫化特性及力学性能。主要涉及硫化温度、偶联剂对体系硫化特性的影响;氧化钐及偶联剂含量对体系力学性能的影响。研究表明,随Sm2O3含量的增加,硫化焦烧时间变长,氧化钐对三元乙丙橡胶(EPDM)体系的力学性能有一定的增强效果,当氧化钐含量为40份时,力学性能最优。用KH-845-4偶联剂处理的氧化钐能够促进体系的硫化,体系的力学性能得到进一步的改善。     

Emission properties of Sm(III) complex having ten-coordination structure

Sammarium(III) complex having ten-coordination structure, bis-(1,10-phenanthroline)tris-(hexafluoroacetylacetonato)samarium(III) (Sm(hfa)₃(phen)₂) was prepared by chelation of tris-(hexafluoroacetylacetonato) samarium(III) (Sm(hfa)₃(H₂O)₂) with 1,10-phenantroline (phen). The characteristic ten-coordination structure of Sm(hfa)₃(phen)₂ was determined by ¹H NMR and elemental analyses. Strong deep-red emission (λ_max=643 nm) and narrow emission band (FWHM=5 nm) of Sm(hfa)₃(phen)₂ originated from electronic allowed transition from characteristics ten coordinate structure. The emission quantum yields Sm(hfa)₃(phen)₂ excited at absorption bands of ligands and Sm(III) ion were found to be 0.36 and 1.4%, respectively.     

Efficient top-emitting organic light-emitting diodes with Sm/Ag bilayer cathode

A bilayer is used as a semitransparent cathode for top-emitting organic light emitting devices (top-emitting OLEDs). The bilayer cathode consists of samarium (Sm) and silver (Ag). Top-emitting OLEDs with the bilayer cathode showed enhanced current injection and high electroluminescence efficiency as compared with a Sm cathode. The maximum current efficiency of the top-emitting OLEDs with a Sm/Ag cathode is 9.9 cd/A, much greater than 4.9 cd/A obtained from the top-emitting OLEDs with a Sm cathode. The improved performance can be attributed to the balance between optical transparency and electrical conductivity of the Sm/Ag cathode.     

PVC membrane and coated graphite potentiometric sensors based on Et4todit for selective determination of samarium(III)

Solution studies on the binding properties of 4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione (Et(4)todit) toward a number of cationic species including some lanthanide ions revealed the occurrence of a selective 1:1 complexation of the ligand with Sm(3+) ion. Consequently, Et(4)todit was used as a suitable neutral ionophore for the preparation of novel polymeric membrane (PME) and coated graphite (CGE) Sm(3+)-selective electrodes. The electrodes exhibit a Nernstian behavior for Sm(3+) ions over wide concentration ranges (1.0 x 10(-5)-1.0 x 10(-1) M for PME and 1.0 x 10(-7)-1.0 x 10(-1) M for CGE) and very low limits of detection (8.0 x 10(-6) M for PME and 1.6 x 10(-8) M for CGE). The proposed potentiometric sensors manifest advantages of relatively fast response, and, most importantly, good selectivities relative to wide variety of other cations, including other lanthanide ions. The selectivity behavior of the proposed Sm(3+)-selective electrodes revealed a great improvement compared to the best previously reported electrode for samarium(III) ion. The potentiometric responses of the electrodes are independent of the pH of the test solution in the pH range 4.0-6.5. The electrodes were successfully applied to the recovery of Sm(3+) ion from tap water samples and also, as an indicator electrode, in potentiometric titration of samarium(III) ions.     

Valence Change and Luminescence of Divalent Samarium in Strontium Borates

1.IlltroductionTheopticalspectraofSm2+inalkaliha1idesandothercrystalswerestudiedbyanumberofw.rk.r.I1~5].Sm2+has4rtconfigurationwhichisisoelectronicwithEu3+anditsluminescentspectrastructureareclosetothatoftheEu'+,therefore,theluminescenceofSm2+inhostwasusedasastructureprobeinmanyhosts[6~9].ItwasreportedthattheEu'+,Sm3+,Yb3+couldbereducedtothecorrespondingdivalentrareearthionsinSrB4O7bysolidstatereactionathightemper-atureinair[lo].TheyproposedthattherigidthIee-dimensionalnetworkofBO4tetrah…     

UV-VUV excited luminescence of SrBPO5:Sm phosphor prepared in air

The high-resolution luminescent spectrum of divalent samarium excited by 355 nm UV light at 77 K, the VUV excitation spectra, the VUV excited emission spectra and EXAFS at Sm-L₃ edge were reported for samarium doped strontium borophosphate, SrBPO₅:Sm prepared by solid state reaction in air at high temperature. The high-resolution luminescent spectrum showed that the divalent samarium ions occupied the C_2υ lattice sites. The VUV excitation spectra indicated that the sample exhibited absorption bands with the maxima at 129 and 148 nm, respectively. The performance of EXAFS at Sm-L₃ absorption edge suggested that the samarium ions were nine-coordinated and the mean distances of bond SmO were 2.38 Å.     

氧化钐/环氧树脂与聚丙烯酸钐/环氧树脂辐射防护材料的制备工艺、微观结构及性能

采用表面处理和接枝聚合的方法分别制备了以环氧树脂为基体,以钐元素为功能元素的氧化钐/环氧树脂与聚丙烯酸钐/环氧树脂辐射防护材料.用X射线衍射、扫描电镜等方法对比研究了通过表面处理法制得的氧化钐/环氧树脂和通过接枝聚合法制得的聚丙烯酸钐/环氧树脂2种材料样品的微观结构;测试了材料的力学性能,并用多道碘化钠(NaI)γ谱仪...     

稀土Sm2O3掺杂钙硼硅发光玻璃的光致发光行为研究

用高温熔融法制备了掺杂Sm2O3的CaO-B2 O3-SiO2(CBS)发光玻璃材料,并对其光谱学特性进行了研究。紫外-可见(UV-Vis)吸收光谱表明Sm2O3掺杂发光玻璃在紫外区有较强吸收并在可见光区具有良好的透过率。光谱学测试表明,掺杂发光玻璃在404nm激发下出现Sm3+的特征发射峰,峰值波长分别位于565.8、602.8和650.4nm。同时,Sm2O3掺杂发光玻璃的荧光发射强度随Sm2O3掺杂摩尔分数的增加出现浓度猝灭效应,其Sm2O3掺杂猝灭浓度约为0.10%(摩尔分数)。此外,在365nm紫外光照射下,Sm2 O3掺杂发光玻璃呈现出红橙色发光,表明其具有将紫外光转换成红橙光的能力,可以进一步应用于光转换和光发射领域。     

Preparation and Superconducting Properties of F-doped SmO_(1-x)F_xFeAs

Here we report the fabrication and superconductivity of the iron-based arsenic oxide SmO1-xFxFeAs compound.X-ray diffraction(XRD) results prove that the lattice parameters a and c decrease systematically with increasing x in between 00.35 the a and c increase with the decrease of x in the SmO1-xFxFeAs.The critical temperature(Tc) increases with increasing x in between 0.15≤x≤0.3,while x>0.3 the Tc decreases with the increase of x.It is found that at x=0.3 SmO0.7F0.3FeAs has the highest onset resistivity transition temperature of 55.5 K.The critical current density(Jc) value at 10 K for the obtained SmO0.7F0.3FeAs is 1.3×10 5 A/cm2(0T).Meanwhile one can estimates Hc2(0) from the slope of the Hc2(T) curve at T =Tc(HC2 is the upper critical field),and for the 90% normal-state resistivity(ρn) criterion(Tc=55 K),Hc2(0) is determined to be ～253 T.     

Homogeneity Range of Samarium Manganite in Air

The solubility limits of samarium and manganese oxides in SmMnO₃ are determined using x-ray diffraction analysis of Sm_{2 ? x}MnxO₃ samples (0.90 ≤ x ≤ 1.20, Δx = 0.02) prepared from oxide mixtures by solid-state reactions in air between 800 and 1400°C. The composition dependences of lattice parameters are presented for samarium manganite synthesized at 1400°C. The solubility of samarium oxide in SmMnO₃ is tentatively attributed to structural defects, and that of manganese oxides is interpreted in terms of structural defects, oxygen nonstoichiometry of samarium manganite, the disproportionation reaction 2Mn³⁺ =Mn²⁺ + Mn⁴⁺, and partial substitution of the resulting Mn₂₊ for Sm₃₊ on the cuboctahedral site of the perovskite structure.     

Effects of samarium content on microstructure and mechanical properties of Mg–0.5Zn–0.5Zr alloy

Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical properties of Mg–0.5Zn–0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic phase changes from Mg₃Sm to Mg₄₁Sm₅ till Sm content exceeds 5.0 wt%. The dynamically precipitated intermetallic phase during hot-extrusion in all Sm-containing alloys is Mg₃Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stimulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg–0.5Zn–0.5 Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% compared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening.     

ZrO2的加入对(CeO2)0.86(SmO1.5)0.14陶瓷性能的影响

探讨了添加 ＺｒＯ_２对 ＣｅＯ_２／Ｓｍ_２Ｏ₃体系电导率和力学性能的影响,并用 ＸＲＤ、ＳＥＭ等对材料的微观性能进行了试验分析．结果发现,添加 ＺｒＯ_２使材料的电导率降低,主要是因为ＺｒＯ_２的固清使得ＣｅＯ_２电解质材料的晶格常数减小,活化能增加造成的;添加 ＺｒＯ_２可提高材料的断裂强度,使材料断裂以穿晶断裂为主,其原因可能是ＺｒＯ_２的固溶强化了晶界;添加 ＺｒＯ_２促进了致密烧结,使晶界结合紧密．实验确定,外加 ２．５ｍｏｌ％ ＺｒＯ_２的 ＣｅＯ_２电解质具有适中的强度和电导率,可以作为电解质材料应用．     

Phase composition and thermal conductivity of zirconia-based thermal barrier coatings

Atmospheric plasma spraying of powder materials has been used to produce thermal barrier coatings (TBCs) based on ZrO₂ stabilized with 7 wt % Y₂O₃, including coatings doped with neodymium and samarium oxides, for state-of-the-art and next-generation high-temperature gas turbine engines. Doping with neodymium and samarium oxides has been shown to reduce the thermal conductivity of the TBCs by 10–20%. At the same time, changes in the phase composition, crystal structure parameters, and microstructure of the TBCs during heat treatment at the service temperature lead to an increase in the thermal conductivity of all the coatings by 50–70%.     

Heterogeneous Structural Distortions Induced by In-Plane and Out-of-Plane Doping in Iron-Based Superconductors

For iron-based superconductors, both the in-plane and out-of-plane doping can cause the superconductivity. In this contribution, we investigated both the electronic structure and local lattice structure induced by in-plane and out-of-plane doping in SmFeAsO-based superconductors probed by X-ray absorption spectroscopy. Data pointed out that upon out-of-plane doping the charge reservoir layers and superconductive layers become closer, enhancing the electron transfer from SmO to FeAs layers, and in the end, almost all the electron carriers were gathered around Fe atoms. On the other hand, for in-plane doping, we observed the elongation of Sm–As bonds but the shrinkage of FeAs layers that promoted the transfer of electron carriers on superconductive layers. Accordingly, it is because of the heterogeneous structural distortions that lead to the different superconducting mechanism of in-plane and out-of-plane doping in iron-based superconductors.     

Lanthanum samarium oxalate — its growth and structural characterization

Lanthanum samarium oxalate (LSO) single crystals are grown in silica gels by the diffusion of a mixture of aqueous solutions of lanthanum nitrate and samarium nitrate into the test tube having the set gel impregnated with oxalic acid. Tabular crystals of LSO having well defined hexagonal basal planes are observed at different depths inside the gel. LSO crystals grown by this method are colourless and transparent. Laue transmission X-ray diffraction pattern of LSO reveals well defined spots with two-fold symmetry along the horizontal axis. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) support that LSO loses water around 120°C, and CO and CO₂ around 350–450°C. The infrared (IR) absorption spectrum of LSO establishes the presence of oxalate (C₂ O₄)²⁻ ions. Energy dispersive X-ray analysis (EDAX) confirms the presence of La and Sm in the sample. X-ray photoelectron spectroscopic (XPS) studies of LSO confirm the presence of La and Sm in their respective oxide states. An empirical structure for LSO has been proposed on the basis of these findings.     

Thermal behaviour of gel-grown pure and mixed rare earth tartrates of yttrium and samarium

Thermal behaviour of gel-grown pure and mixed rare earth tartrates of yttrium and samarium is investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermal behaviour suggests that the materials are unstable at lower energies and pass through various stages of decomposition, decomposing to respective rare earth oxides which remain stable on further heating. It is estimated that both pure yttrium and pure samarium tartrate crystals carry eight waters of hydration, while mixed yttrium samarium tartrate crystals carry six waters of hydration. Critical examination of TG and DSC curves shows that the initial decompositions are endothermic and the latter are exothermic. Thermal kinetics of these materials has been worked out using Horowitz-Metzger, Piloyan-Novikova and Coats-Redfern equations. Application of these equations to these materials yields values of activation energy, order of reaction and frequency factor which are in reasonably good agreement.