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991.
Shanshan Liu Daniel Olive Jeff Terry Carlo U. Segre 《Journal of Nuclear Materials》2009,392(2):259-263
The corrosion of fuel cladding and structural materials by lead and lead-bismuth eutectic in the liquid state at elevated temperatures is an issue that must be considered when designing advanced nuclear systems and high-power spallation neutron targets. In this work, lead corrosion studies of molybdenum were performed to investigate the interaction layer as a function of temperature by X-ray absorption spectroscopy. In situ X-ray absorption measurements on a Mo substrate with a 3-6 μm layer of Pb deposited by thermal evaporation were performed at temperatures up to 900 °C and at a 15° angle to the incident X-rays. The changes in the local atomic structure of the corrosion layer are visible in the difference extended X-ray absorption fine structure and the linear combination fitting of the X-ray absorption near-edge structure to as-deposited molybdenum sample and molybdenum oxide (MoO2 and MoO3) standards. The data are consistent with the appearance of MoO3 in an intermediate temperature range (650-800 °C) and the more stable MoO2 phase dominating at high and low temperatures. 相似文献
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Effect of inductively coupled plasma surface treatment on silica gel and mesoporous MCM-41 particles
J A JUAREZ-MORENO U CHACON-ARGAEZ J BARRON-ZAMBRANO C CARRERA-FIGUEIRAS P QUINTANA-OWEN W TALAVERA-PECH Y PEREZ-PADILLA A AVILA-ORTEGA 《等离子体科学和技术》2018,20(6):65506-113
Silica gel and MCM-41 synthesized mesoporous materials were treated with either oxygen (O2),hexamethyldisiloxane (HMDSO) and organic vapors like ethanol (EtOH),and acrylonitrile (AN) inductive plasma.The radiofrequency power for the modification was fixed to 120 W and 30 min,assuring a high degree of organic ionization energy in the plasma.The surface properties were studied by infrared spectroscopy (FTIR),scanning electron microscopy,x-ray photoelectron spectroscopy and dynamic light scattering technique was used for characterizing size distributions.When the silica and MCM-41 particles were modified by AN and HMDSO plasma gases,the surface morphology of the particles was changed,presenting another color,size or shape.In contrast,the treatments of oxygen and EtOH did not affect the surface morphology of both particles,but increased the oxygen content at the surface bigger than the AN and HMDSO plasma treatments.In this study,we investigated the influence of different plasma treatments on changes in morphology and the chemical composition of the modified particles which render them a possible new adsorbent for utilization in sorptive extraction techniques for polar compounds. 相似文献
995.
A new approach for extraction of clinically useful parameters from the ECG signal is presented using the system identification technique of CZT on the DCT-transformed signal. A one to one relationship between the model singularities and the significant points in the time signal is arrived at. The method allows the determination of R-R interval needed in rhythm analysis. The complex cepstrum is used for identifying and removing the effect of zeros outside the unit circle. A significant data compression of 1 in 10 is achieved. A large number of continuous strips of ECG data are analyzed and the results are presented. 相似文献
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Unusually small-sized (2 - 2.5 μ) starch granules were isolated from black pepper (Piper nigrum) in 25 – 38% yield. The granules having an amylose content of 18% were non-ionic in nature and exhibited low solubility and low swelling power in water, but high solubility in DMSO. The amylogram peak viscosity of the starch was about 530 B. U. with a very little set back (∼ 550 B. U.) on cooling, indicating a stable linear molecule very strongly associated with amylopectin. X-ray power pattern revealed the starch granules to be of A-type. 相似文献
1000.
The study deals with comparison of the susceptibility to fungal glucoamylase and salivary α-amylase of starch granules from navane, panivaragu, black pepper and black gram. The crude glucoamylase was purified by fractionation and column chromatography to give two pure fractions of which one was used. The rate of amylolysis was followed by estimating the amount of glucose and maltose released. The type and extent of damage of the starch granules were observed by scanning electron microscopy which revealed characteristic degradation patterns in navane and panivaragu, whereas black gram granules were resistant to the attack. Very small-sized black pepper starch granules did not exhibit any obvious signs of amylolytic attack. 相似文献