Preparation of La0.5Li0.5TiO3 perovskite thin films by the sol–gel method

Perovskite La_0.5Li_0.5TiO₃ (LLT) thin films, 0.2–1 μm thick, were deposited on non-alkali aluminoborosilicate glass substrates (NA substrates) and glass substrates with ITO (indium tin oxide) coatings (ITO substrates) by the sol–gel method. Alkoxide-based solutions containing titanium alkoxide, lithium alkoxide and lanthanum alkoxide and acetate-based solutions containing titanium alkoxide, lithium acetate and lanthanum acetate, were used as coating solutions. Impurity phases tended to be precipitated on heat treatment in the films derived from the acetate-based solutions. Addition of acetylacetone or partial substitution of lead for lithium in the acetate-based solutions, however, was effective in suppressing the precipitation of impurity phases. Preferred orientation of the LLT (1 1 1/2) plane was observed in the films prepared from the acetate-based solutions when NA substrates were used, whereas the employment of the alkoxide-based solutions or ITO substrates and the partial substitution of lead for lithium, reduced the preferred orientation. The electrical conductivity of the films was much lower than the values reported for the sintered materials. This revised version was published online in November 2006 with corrections to the Cover Date.     

Agmatine pretreatment protects retinal ganglion cells (RGC-5 cell line) from oxidative stress <i>in vitro</i>

Agmatine, 2-(4-aminobutyl)guanidine, has been reported to have neuroprotective effects against various neuronal damages. In this study it was investigated whether agmatine pretreatment rescues the retinal ganglion cells from oxidative injury in vitro. After differentiation of transformed rat retinal ganglion cells (RGC-5 cell line) with staurosporine, agmatine (0.0 to 100.0 μM) pretreatment was performed for 2 hours. Subsequently, they were exposed to hydrogen peroxide (0.0 to 2.5 mM) as an oxidative stress. Cell viability was monitored for up to 48 hours with the lactate dehydrogenase (LDH) assay and apoptosis was examined by the terminal deoxynucleotide transferase-mediated terminal uridine deoxynucleotidyl transferase nick end-labeling (TUNEL) method. As a result, differentiated RGC-5 cells were found to have decreased viability after addition of hydrogen peroxide in a dose-dependent manner. This hydrogen peroxide induced cytotoxicity caused apoptosis characterized by DNA fragmentation. Agmatine pretreatment not only increased cell viability but also attenuated DNA fragmentation. In conclusion, agmatine pretreatment demonstrated neuroprotective effects against oxidative stress induced by hydrogen peroxide in differentiated RGC-5 cells in vitro. This suggests a novel therapeutic strategy rescuing retinal ganglion cells from death caused by oxidative injury     

Present Situation of Fukushima and Possibility of Decontamination Technology by Superconducting Magnetic Separation System

A large amount of radionuclides were spread by the accident of Fukushima Daiichi nuclear power plant in 2011. The situation of surrounding area of nuclear power plant is momentarily changing. In order to consider for decontamination or volume reduction of radioactive wastes, it is necessary taking into account not only the technical needs but also feelings of inhabitants, reduction of environmental load, reduction of the radiation exposure on workers, and efficiency and cost of decontamination work. In this paper, the application possibility of superconducting magnetic separation system for decontamination and volume reduction was discussed compared with other technologies from above multidirectional viewpoint.     

Effects of Thermal Treatment on Radical-scavenging Activity of Single and Mixed Polyphenolic Compounds

ABSTRACT: Rutin, luteolin, luteolin-7-glucoside, and chlorogenic acid gradually decomposed during heating at 100°C. Even though they rapidly decomposed at 180°C, some decomposition products still had radical-scavenging activity. When rutin was heated in the presence of chlorogenic acid, decomposition of rutin was almost totally inhibited at 100°C, but was reduced at 180°C. These results suggest that the radical-scavenging activity is more stable than the content of original polyphenolic compounds in foods during cooking and processing.     

Kinetic Studies of Eutectoid Decomposition of CuFe5O8

The kinetics and mechanism of eutectoid decomposition of CuFe₅O₈ were studied by X-ray diffractometer, electron probe microanalyzer, and reflecting-light microscope techniques. The isothermal decomposition curves were sigmoidal and the maximum rate of decomposition occurred at ∼600°C. Sigmoidal-type curves indicated that the decomposition proceeded by a process of nucleation and growth. Kinetic data were best expressed by Avrami's equation with n≃2 and n≃4 below and above 850°C, respectively. A "site saturation" mechanism is suggested. Bainite-type and pearlite-type microstructures were observed below and above 800°C, respectively. Grain boundaries were active sites in the nucleation process.     

Al_4O_4C的碳热还原合成及其反应动力学

以氧化铝(Al2O3)和石墨(C)为原料,采用碳热还原工艺合成铝氧碳(Al4O4C),借助于X射线衍射仪和场发射扫描电子显微镜研究了加热温度和保温时间对合成铝氧碳(Al4O4C)的影响。结果表明:提高加热温度,可加快Al2O3和C反应生成Al4O4C的反应速率;延长保温时间可增大Al2O3和C反应生成Al4O4C的反应程度。在反应初期主要为固-固反应,Al2O3和C直接接触反应生成Al4O4C和一氧化碳(CO);后期主要为气-固反应,Al2O3和CO气体反应生成Al4O4C和二氧化碳(CO2)。计算得到气-固反应的频率因子和活化能分别为338.66和264.19kJ/mol。     

High-Temperature Reaction Between Cemented Tungsten Carbide and Copper

Interdiffusion in the system cemented tungsten carbide-molten copper has been studied in the range ≤1120°C with special emphasis on the effects of WC grain size and Co content. Techniques used for analyzing the diffusion layers obtained are EPMA, optical microscopy, and microhardness measurement. A Cu-bonded WC layer develops with simultaneous diffusion of Co from the cemented carbide into the bulk copper. The Cu-bonded WC layer grows until a Co-rich layer forms at the Cu/WC-Co interface; further heating pushes the Cu-bonded WC layer deep into the bulk cemented carbide without any significant change in layer thickness. When the WC grain size is reduced and the cobalt content increased, the penetration of copper into cemented carbides increases. A tentative mechanism of interdiffusion has been proposed based on the experimental results.     

Crystallization of Hexagonal BaNb2O6

Pure hexagonal BaNb₂O₆ crystallizes at 640° to 700°C from an amorphous material prepared by simultaneous hydrolysis of barium and niobium alkoxides. The structure is characterized by layer networks of NbO₆ octahedra. Crystallization isotherms are described by the Avrami equation In (1—f) = -ktⁿ with n=2; the activation energy is 268 kJ-mol-'. Hexagonal BaNb₂O₆ transforms to the ortho-rhombic modification one at 12.50° to 1310°C.