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Microstructure characterization has become indispensable to the study of complex materials, such as strongly correlated oxides, and can obtain useful information about the origin of their physical properties. Although atomically resolved measurements have long been possible, an important goal in microstructure characterization is to achieve element-selective imaging at atomic resolution. A combination of scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) is a promising technique for atomic-column analysis. However, two-dimensional analysis has not yet been performed owing to several difficulties, such as delocalization in inelastic scattering or instrumentation instabilities. Here we demonstrate atomic-column imaging of a crystal specimen using localized inelastic scattering and a stabilized scanning transmission electron microscope. The atomic columns of La, Mn and O in the layered manganite La1.2Sr1.8Mn2O7 are visualized as two-dimensional images.

Electron holography reveals how lithium ions are distributed during the charge/discharge cycle of a lithium battery. A steep potential drop and a gradually extended slope (ca. 1.5 μm) due to the electrical double layer are formed near the electrode/electrolyte interface, where the resistance to lithium ion transfer occurs.

We have successfully synthesized the highly c-axis-oriented polycrystals of apatite-type lanthanum silicate by the reactive diffusion technique. When the La 2 SiO 5 /La 2 Si 2 O 7 diffusion couples were isothermally heated at 1773−1873 K for 5−100 h, the apatite polycrystals were readily produced in the form of a layer at the interfacial boundaries. The annealed couples were characterized using optical microscopy, micro-Raman spectroscopy, X-ray diffractometry, and electron probe microanalysis. The product layers were composed of the highly c-axis-oriented prismatic crystallites, with their elongation directions being almost parallel to the diffusion direction. The formation of the apatite layer was controlled by volume diffusion, the overall reaction of which is described by (10 + 6x)La 2 SiO 5 + (4−3x)La 2 Si 2 O 7 → 3La 9.33+2x (SiO 4 ) 6 O 2+3x (0.01 ≤ x ≤ 0.13). The apatite layer formed at 1873 K was characterized by the steady decrease of the x-value along the diffusion direction from 0.13 at the La 2 SiO 5 /apatite interface to 0.01 at the apatite/La 2 Si 2 O 7 interface. We have also prepared sandwich-type La 2 Si 2 O 7 /La 2 SiO 5 /La 2 Si 2 O 7 diffusion couples and heated them at 1873 K for 100 h. The annealed couple was mechanically processed, and the thin-plate electrolyte consisting of the highly c-axis-oriented polycrystal was obtained. The oxide-ion conductivity was determined from the impedance spectroscopy data at 573−973 K, which steadily increased from 2.4 × 10 −3 S/cm to 2.39 × 10 −2 S/cm with increasing temperature. The empirical activation energy of conduction was 0.35 eV, which compares well with the calculated migration energy of 0.32 eV in a previous study.

Two cases of primary pulmonary artery sarcoma are reported. The patient in the first case was a 61‐year‐old male with a two‐year history of cough and exertional dyspnea, who died of intractable cardiac failure two months after admission without establishment of a diagnosis related to the etiology of cardiac failure. Autopsy revealed a sessile tumor within the pulmonary trunk and a solitary metastatic lesion in the lung. Histologic, immunohistocyto‐chemical and electron microscopic studies were performed and a diagnosis of malignant mesenchymoma was made. The patient in the second case was a 32‐year‐old male complaining of exertional dyspnea and back pain. Radiologic studies indicated a mediastinal tumor involving the pulmonary artery. Exploratory thoracotomy revealed that the mediastinal mass arose from the left pulmonary artery. He died of respiratory failure 26 months after onset of his initial symptoms. Histologic, immunocytochemical and electron microscopic studies of both surgical and autopsy materials revealed a malignant fibrous histiocytoma. One hundred ten previously reported cases of this tumor are reviewed, and its clinicopathologic and morphologic features and probable histogenesis are discussed. ACTA PATHOL JPN 38: 883∼896, 1988.

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