Search

SiGe is a promising anode material for replacing graphite in next generation thin-film batteries owing to its high theoretical charge/discharge capacity. Metal-induced layer exchange (LE) is a unique technique used for the low-temperature synthesis of SiGe layers on arbitrary substrates. Here, we demonstrate the synthesis of Si1−xGex (x = 0–1) layers on plastic films using Al-induced LE. The resulting SiGe layers exhibited high electrical conductivity (up to 1200 S cm−1), reflecting the self-organized doping effect of LE. Moreover, the Si1−xGex layer synthesized by the same process was adopted as the anode for the lithium-ion battery. All Si1−xGex anodes showed clear charge/discharge operation and high coulombic efficiency (≥ 97%) after 100 cycles. While the discharge capacities almost reflected the theoretical values at each x at 0.1 C, the capacity degradation with increasing current rate strongly depended on x. Si-rich samples exhibited high initial capacity and low capacity retention, while Ge-rich samples showed contrasting characteristics. In particular, the Si1−xGex layers with x ≥ 0.8 showed excellent current rate performance owing to their high electrical conductivity and low volume expansion, maintaining a high capacity (> 500 mAh g–1) even at a high current rate (10 C). Thus, we revealed the relationship between SiGe composition and anode characteristics for the SiGe layers formed by LE at low temperatures. These results will pave the way for the next generation of flexible batteries based on SiGe anodes. [ABSTRACT FROM AUTHOR]

We describe a simple and effective approach to introduce a functional group into polymer film on a solid surface using reactive polymer LB films. N-dodecylacrylamide copolymers containing terminal amino groups in the side chains as the reactive moiety form a stable monolayer, and the monolayer was transferred onto a solid support to modify the solid surface using the Langmuir-Blodgett method. The transferred coatings were characterized with fluorescence, IR spectroscopies, and X-ray diffraction. The reactivity of the terminal amino group incorporated in the LB films was investigated in detail using fluorescein isothiocyanate (FITC) as a fluorescent probe. The chemical reaction between amino groups in the LB films and FITC in the bulk solution was completed within approximately 30 minutes and the chemical bond formation was confirmed by infrared spectroscopy. Furthermore, the fluorescent image of the multilayers reacted with FITC were observed with fluorescent microscopy. This method is effective for tailoring functional organic ultrathin films on solid substrates. [ABSTRACT FROM AUTHOR]

It is known that metallurgical phenomena such as recovery, recrystallization, grain growth, and aging are due to the diffusion of constituent atoms in materials. The heat treatments that cause these phenomena are conducted defining both time and temperature. In the diffusion process, it is the diffusion distance that is defined by both time and temperature. Therefore, the authors surmise that there must be a relationship between the change of material properties as a result of heat treatment and the diffusion distances of constituent atoms. Under this assumption, diffusion distances of constituent atoms at recovery, recrystallization, grain growth, and aging in aluminum and copper alloys were examined. As a result, it was found that these phenomena take place at the fixed diffusion distances peculiar to the materials and phenomena. Therefore, the relationship between time and temperature was decided in terms of the fixed diffusion distances. In this respect, empirically used “normalized annealing time” turns out to mean the diffusion distance. [ABSTRACT FROM AUTHOR]

The article presents several Color Doppler fetal electrocardiographic images. In the images is a 33-year-old woman's two left pulmonary veins and a right pulmonary vein joining a common chamber. The woman is at 31 weeks of gestation because her first child underwent surgery for total anomalous pulmonary venous return (TAPVR). More information is given in the article.