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21.
Copper films with (1 1 1) texture are of crucial importance in integrated circuit interconnects. We have deposited strongly (1 1 1)-textured thin films of copper by atomic layer deposition (ALD) using [2,2,6,6-tetramethyl-3,5-heptadionato] Cu(II), Cu(thd)2, as the precursor. The dependence of the microstructure of the films on ALD conditions, such as the number of ALD cycles and the deposition temperature was studied by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. Analysis of (1 1 1)-textured films shows the presence of twin planes in the copper grains throughout the films. SEM shows a labyrinthine structure of highly connected, large grains developing as film thickness increases. This leads to low resistivity and suggests high resistance to electromigration. 相似文献
22.
We report on picosecond time resolved spectroscopy of photogenerated infrared active vibrations in thin films of 2,5-dioctyloxy poly(phenylene vinylene). We excited the films by ?4 ps long pulses of 565 nm laser light with 2×1013 photons/cm2 per pulse and repetition rate of 76 MHz. We then followed the temporal evolution of the infrared active vibrational (IRAV) spectrum using a subsequent, variably delayed, weak tunable IR probe pulses of similar temporal duration. Under these conditions, we show clear spectroscopic evidence for photogenerated infrared active vibrations at times which are shorter than our temporal resolution (<4 ps). We suggest that the transient IRAV absorption is due to secondary polarons formation following exciton dissociation. 相似文献
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24.
Infant malnutrition and mortality are common in Africa, although Africa is endowed with agricultural produce that could be harnessed through processing to produce adequate infant food. This project was set up to explore the possibility of using local raw materials to develop a nutritious, low‐dietary‐bulk, cheap infant food. The materials used included cereal (maize), pulses (soybean and groundnut) and tuberiferous plants (cooking banana). The grains were first germinated and dried or kilned before milling and formulation. The malted products were compared with fermented ones in terms of nutritional, dietary bulk and acceptability criteria. Malting increased the nutrient content, reduced the dietary bulk and enhanced the taste of the infant food. In terms of protein content, least gelation concentration and overall acceptability, malted samples had values in the range of 138–151 mg g?1, 150–175 g l?1 and 7.2–8.82 respectively, while the control (fermented) sample had values of 54 mg g?1, 100 g l?1 and 6.29 respectively. Roasting of malted cereals above 55 °C reduced the bulk reduction ability but enhanced the taste of the products. A combination of malted maize and soybean, roasted groundnut and cooking banana in the ratio of 50:15:15:20 gave a very recommendable weaning food for infants between the ages of 6 months and 2 years. © 2002 Society of Chemical Industry 相似文献
25.
HR Stennicke UH Mortensen U Christensen SJ Remington K Breddam 《Canadian Metallurgical Quarterly》1994,7(7):911-916
Carboxypeptidase Y is a serine carboxypeptidase isolated from Saccharomyces cerevisiae with a preference for C-terminal hydrophobic amino acid residues. In order to alter the inherent substrate specificity of CPD-Y into one for basic amino acid residues in P'1, we have introduced Asp and/or Glu residues at a number of selected positions within the S'1 binding site. The effects of these substitutions on the substrate specificity, pH dependence and protein stability have been evaluated. The results presented here demonstrate that it is possible to obtain significant changes in the substrate preference by introducing charged amino acids into the framework provided by an enzyme with a quite different specificity. The introduced acidic amino acid residues provide a marked pH dependence of the (kcat/Km)FA-A-R-OH/(kcat/Km)FA-A-L-OH ratio. The change in stability upon introduction of Asp/Glu residues can be correlated to the difference in the mean buried surface area between the substituted and the substituting amino acid. Thus, the effects of acidic amino acid residues on the protein stability depend upon whether the introduced amino acid protrudes from the solvent accessible surface as defined by the surrounding residues in the wild type enzyme or is submerged below. 相似文献
26.
Cicalese F. Vaccaro U. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2002,48(4):933-938
We prove that the entropy is a supermodular and subadditive function on the lattice of all n-dimensional probability distributions, ordered according to the partial order relation defined by majorization among vectors 相似文献
27.
This paper presents a new self-routing packet network called the plane interconnected parallel network (PIPN). In the proposed design, the traffic arriving at the network is shaped and routed through two banyan network based interconnected planes. The interconnections between the planes distribute the incoming load more homogeneously over the network. The throughput of the network under uniform and heterogeneous traffic requirements is studied analytically and by simulation. The results are compared with the results of the baseline network and another banyan network based parallel interconnection network. It is shown that, for the proposed design, a higher degree of heterogeneity results in better performance 相似文献
28.
In this paper the approach of BRASIL in modelling digitalintegrated circuits is presented. BRASIL consists of a timingsimulator for digital MOS circuits coupled with an algorithmfor circuit simulation. The timing simulation is based upon afast macromodelling approach and the calculation of time-variantRC networks. The circuit simulator takes advantage of structuringthe system of nodal equations. With BRASIL a fast and accuratesimulation of digital circuits, with special regard to the analogbehaviour of highly integrated systems is possible. 相似文献
29.
For two applications of fuel cells (SOFC and IMFC) system configurations and energy balances are presented. A decentralized combined heat and power plant on SOFC basis can be designed as a flexible system with high efficiency. A drive system with methanol reformer and fuel cell (IMFC) in comparison with a natural gas combustion engine has lower energy comsumption and much lower emissions. 相似文献
30.