Su Wenhui

XPS study of CeTbO3+δ synthesized by high pressure and temperature method

The samples of CeTbO3+δ synthesized by high pressure and high temperature method were studied by XPS. It was found that Tb4+ ion began to transform to Tb3+ at about 600° C and Ce4+ to Ce3+ about 800° C. Single phase compound of CeTbO3+δ having fluorite structure was formed at 1000° C, and in the compound the Ce ions had been in mixed valence state. Existence of Ce3+ ions in compounds could be detected with the shift of the 888 eV peak and the change of relative intensity of it to the 882 eV peak. The duration stability of CeTbO3+δ synthesized by high pressure and temperature method was investigated.

AN INVESTIGATION USING HIGH-PRESSURE SYNTHESIS OF DOUBLE-RARE-EARTH OXIDES OF ABO3-COMPOSITION

Abstract The synthesis of the double-rare-earth oxides PrTmO3, PrYbO3, NdYbO3, NdLuO3, LaGdO3 and LaDyO3 is investigated by using high pressure and high temperature methods (4.0 GPa, 1200–1350°C) for the first time. The analyses by X-ray diffraction show that all products (except PrYbO3) are single-phase materials: NdLuO3 belongs to the P-type structure, PrYbO3 is mainly P-type, and the others belong to B-type. The PrTmO3 is a new material which has not yet been reported in the literature.

Solid-state synthesis and properties of SmCoO3

In this paper, perovskite oxide SmCoO3 was prepared by the solid-state reaction method using Co2O3 and Sm2O3 as raw materials. The structure and properties of the samples were investigated by XRD, Raman spectral techniques, and DC measurements and so on. The results of XRD and Raman spectra showed that the mixtures of Co2O3 and Sm2O3 can react to produce a single phase perovskite oxide SmCoO3 around 1353 K. The single-phase SmCoO3 changes from an insulator to a semi-conductor and transition occurs around 470 K. The thermal expansion coefficient (2.17 × 10−5 K−1) of the single-phase SmCoO3 is approximately equal to that of doped LaGaO3, but much bigger than that of SDC(Ce0.85Sm0.15O2) above 873 K.

The effect of electron effective mass mismatch on electron - phonon scattering rate in a quantum well

The electron - phonon scattering rate due to the deformation potential is calculated in a semiconductor quantum well structure, in which the electron effective mass mismatch is taken into account. By comparison with the scattering rates calculated by the infinitely high model and the finitely high square quantum well model without the electron effective mass mismatch, it is shown that the scattering rate decreases owing to the effect of the electron effective mass mismatch.

151Eu and 57Fe Mössbauer spectroscopy study on rare-earth transition element oxides

Abstract Series of rare-earth transition element oxides Eu0.2R0.8FeO3 and EuFe0.8M0.2O3 ( R = rare-eartjs, M=Sc, Cr, Mn, Co) are synthesized. X-ray diffraction determinations show that these compounds possess perovskite structures. Mossbauer spectra of both 151Eu and 57Fe are studied. The results show that the isomer shift of 151Eu in Eu0.2R0.8FeO3 depends on the unit cell volume V 1 3 of the compounds in a linear fashion. There is a certain relationship between the quadropole splitting and the lattice parameters 1 a 3 in Eu0.2R0.8FeO3. The hyperfine field parameters Hin of 57Fe Mossbauer spectra are relating to R ions.

An investigation of the distribution of boron atoms in the aggregate crystals of diamond containing boron

Abstract With the single crystals of diamond without boron as starting materials and then by adding boron atoms to their surfaces, aggregate crystals of diamond have been synthesized under high pressure. By the analytical methods of modified particle-tracking autoradiography and use of an ion microprobe, the microstructure of the boron-atom distribution in the aggregate crystal of diamond has been directly observed to test and verify the distribution model of boron atoms. The reasons why the oxidation resistance and the chemical inertia for the aggregate crystals of diamond containing boron are excellent are explained.

An investigation of the effect of high pressure on the synthesis of LaLnO3 compounds

Abstract In the present paper, by using the high pressure method for the first time, the complex oxides of rare earth LaLnO3 (Ln  Ho, Er, Yb, Lu, Y) have been successfully synthesized at 29 kb. Compared with the synthesis at atmospheric pressure it can be seen that, for the most part, the high pressure is able to decrease the temperature of synthesis, accelerate the reaction rate, increase the transformation rate of products, greatly shorten the synthetic time and, at the same time, increase the dissociation temperature.

A method of quenching in fusing state under high static pressure used to study quasicrystals

Abstract In this paper, a new method of quenching in fusing state under high static pressure (MQFSHP), which was developed in the beginning of 1986 by our group1,2, used to study quasicrystals in alloys has been introduced.

Mössbauer effect studied in rare-earth oxides (REu)O3 (R = Pr, Nd, Sm)

Abstract Both X-ray diffraction and the Mossbauer effect have been used to study the double rare-earth oxide solid solutions (REu)O3 (R = Pr, Nd, Sm), which were synthesized with a combination of high pressure and high temperature for the first time. It is shown that all products are of the B-type (monoclinic) structures of single phase. The hyperfine interactions depend strongly on the ligand volume of Eu ions.

中温固体氧化物燃料电池阴极材料Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 的制备与性能研究

采用固相法合成Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ（x=0、0.1、0.2、0.3、0.4）阴极材料。利用X射线衍射（XRD）和扫描电子显微镜（SEM）对其结构和微观形貌进行了表征。XRD测试结果表明Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ样品经1000℃, 烧结10 h后形成了立方钙钛矿结构。从样品的电镜照片看出样品具有均匀的孔隙率, 电解质（Ce0.85Sm0.15O1.925）-阴极（Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ）之间的界面结合良好。电化学交流阻抗测试结果表明Ba1-xSrxCo0.7Fe0.2Nb0.1O3-δ中掺入Sr可以明显地降低阴极的极化电阻, 随着Sr含量的增多, 阴极的界面极化电阻（RP）先减少后增大, 当Sr的含量x为0.2时Rp 值最小。以Ce0.85Sm0.15O1.925（SDC）电解质为支撑体, Ni0.9Cu0.1-SDC为阳极, Ba0.8Sr0.2Co0.7Fe0.2Nb0.1O3-δ为阴极的单电池的最大功率密度在600℃时达到155 mW/cm2。实验结果表明Ba0.8Sr0.2Co0.7Fe0.2Nb0.1O3-δ材料是一种电化学性能较为优良的中温固体氧化物燃料电池阴极材料。采用固相法合成Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ ( x =0、0.1、0.2、0.3、0.4)阴极材料。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构和微观形貌进行了表征。XRD测试结果表明Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 样品经1000℃, 烧结10 h后形成了立方钙钛矿结构。从样品的电镜照片看出样品具有均匀的孔隙率, 电解质(Ce 0.85 Sm 0.15 O 1.925 )-阴极(Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ )之间的界面结合良好。电化学交流阻抗测试结果表明Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 中掺入Sr可以明显地降低阴极的极化电阻, 随着Sr含量的增多, 阴极的界面极化电阻(RP)先减少后增大, 当Sr的含量 x 为0.2时 R p 值最小。以Ce 0.85 Sm 0.15 O 1.925 (SDC)电解质为支撑体, Ni 0.9 Cu 0.1 -SDC为阳极, Ba 0.8 Sr 0.2 Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 为阴极的单电池的最大功率密度在600℃时达到155 mW/cm 2 。实验结果表明Ba 0.8 Sr 0.2 Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 材料是一种电化学性能较为优良的中温固体氧化物燃料电池阴极材料。采用固相法合成Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ ( x =0、0.1、0.2、0.3、0.4)阴极材料。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构和微观形貌进行了表征。XRD测试结果表明Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 样品经1000℃, 烧结10 h后形成了立方钙钛矿结构。从样品的电镜照片看出样品具有均匀的孔隙率, 电解质(Ce 0.85 Sm 0.15 O 1.925 )-阴极(Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ )之间的界面结合良好。电化学交流阻抗测试结果表明Ba 1- x Sr x Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 中掺入Sr可以明显地降低阴极的极化电阻, 随着Sr含量的增多, 阴极的界面极化电阻(RP)先减少后增大, 当Sr的含量 x 为0.2时 R p 值最小。以Ce 0.85 Sm 0.15 O 1.925 (SDC)电解质为支撑体, Ni 0.9 Cu 0.1 -SDC为阳极, Ba 0.8 Sr 0.2 Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 为阴极的单电池的最大功率密度在600℃时达到155 mW/cm 2 。实验结果表明Ba 0.8 Sr 0.2 Co 0.7 Fe 0.2 Nb 0.1 O 3- δ 材料是一种电化学性能较为优良的中温固体氧化物燃料电池阴极材料。