Constitutional supercooling in heavily As-doped Czochralski Si crystal growth

Heavily arsenic (As) doped Si crystals were grown by the Czochralski (CZ) method, and constitutional supercooling in As-doped CZ-Si crystal growth was investigated. When the As concentration in the crystal was high, cellular growth was induced and SiAs precipitates were then observed following the cellular structure. The As concentration increases in the cellular structure along the growth direction and around the precipitates it reaches approximately 4 at%, which corresponds to the maximum solid solubility of As in Si. According to the estimation of critical growth conditions for constitutional supercooling, it qualitatively obeys the theoretical equation of constitutional supercooling. (C) 2013 Elsevier By. All rights reserved.JOURNAL OF CRYSTAL GROWTH. 393:42-44 (2014)journal articl

Ab-initio Molecular Dynamics Simulation of Li Insertion in C_<60>

Complexes composed of fullerenes and metal elements offer important examples as new nanomaterials in the field of materials design. In the collisions between C^-_ and Li^+ in plasma state, there is a possibility that the endohederal fullerene, Li@C_ is created as well as Li@C_ and so on. To study this phenomenon theoretically, we perform an all-electron mixed basis ab initio molecular dynamics simulation at 1, 000K which was developed by ourselves. When Li^+ with the kinetic energy ～5eV hits the center of a six-membered ring of C^-_, an endohedral complex, Li@C_ is created. This direcet insertion process is possible because the ionic radius of Li^+ is shorter then the radius of a six-membered ring. However, if either the kinetic energy is lower or the collision occurs off-center, the Li^+ ion stays outside and C_ is deformed by the shock

Magnetic structure and spin dynamics of quasi-one-dimensional spin-chain antiferromagnet BaCo2V2O8

We report a neutron diffraction and muon spin relaxation muSR study of static and dynamical magnetic properties of BaCo2V2O8, a quasi-one-dimensional spin-chain system. A proposed model for the antiferromagnetic structure includes: a propagation vector k_AF = (0, 0, 1), independent of external magnetic fields for fields below a critical value H_c(T). The ordered moments, of 2.18 \mu_B per Co ion, are aligned along the crystallographic c-axis. Within the screw chains, along the c axis, the moments are arranged antiferromagnetically. In the basal planes the spins are arranged ferromagnetically (forming zig-zags paths) along one of the axis and antiferromagnetically along the other. The temperature dependence of the sub-lattice magnetization is consistent with the expectations of the 3D Ising model. A similar behavior is observed for the internal static fields at different muon stopping sites. Muon time spectra measured at weak longitudinal fields and temperatures much higher than T_N can be well described using a single muon site with an exponential muon spin relaxation that gradually changes into an stretched exponential on approaching T_N. The temperature-induced changes of the relaxation suggest that the Co fluctuations dramatically slow down and the system becomes less homogeneous as it approaches the antiferromagnetic state.Comment: 7 pages, 9 figure

Chemotherapy-Induced Oesophageal Stricture in a Child with Osteosarcoma: A Case Report

Treatment with a combination of chemotherapy and radiotherapy is known to be associated with oesophageal stricture in both children and adults with malignancies. However, oesophageal stricture resulting from chemotherapy alone is a rare complication, with few reports on it. We experienced a rare paediatric case of oesophageal stricture caused by chemotherapy for osteosarcoma of the left distal femur. After completion of the chemotherapy course, the patient showed dysphagia caused by the oesophageal stricture and underwent balloon dilatation for the oesophageal stricture. After balloon dilatation, he was able to ingest solid foods, and the oesophagus was normal without any strictures at the last follow-up (20 months after ballooning). Therefore, oesophageal stricture should be considered as a complication of treatment with chemotherapy alone in children with malignancies

Extraskeletal Osteosarcoma of the Thigh: An Autopsy Case Report

We report a case of extraskeletal osteosarcoma (ESOS) and autopsy findings. A 35-year-old man presented with an ossified tumor in the right thigh and lung metastasis. The lung tumors continued to develop despite multiagent chemotherapy and caused death within 8 months. Autopsy revealed many secondary lesions in the lungs, especially in the left lung. Histopathologically, the primary tumor and one of the secondary tumors showed proliferation of spindle-shaped tumor cells focally forming lace-like osteoid material. Therefore, we made a definite diagnosis of ESOS