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21.
Auger electron spectroscopy (AES) depth profiling was used to study the oxidation phenomena of AISI316L stainless steel during treatment with oxygen plasma. Samples were exposed to low-pressure RF plasma with a high dissociation degree, so that the flux of oxygen atoms onto the sample surface exceeded 1024 m−2 s−1. A set of samples was oxidized 4 min at different temperatures up to 1300 K during plasma treatment. AES measurements showed that the oxide film thickness increased with the increasing temperature. The thickness of the oxide film on the samples oxidized in plasma at 300 K was nearly the same as for the untreated sample. The thickness of the oxide film of the samples which were oxidized at 1000 K was about 170 nm and it consisted of iron oxide. The thickest oxide film of about 350 nm was found on the samples heated in oxygen plasma to 1300 K. Depth profiling showed the uppermost layer of manganese oxide, followed by a mixture of chromium oxide and iron oxide. The scanning electron microscope analyses showed a dramatic increase of the surface roughness. 相似文献
22.
This article presents our continuing efforts to develop a model of the Internet-based mortgage market in Poland. It sums up modeling research done over the last 4 years, also showing the stages and the process of building and verifying the proposed model consisting of three submodels. The submodels are described for three market situations; that is, a stable market, financial crisis, and economic boom. The proposed model variables are analyzed statistically and the submodels are verified. The article presents the most current stage of model development and concludes with suggestions for further research in this area leading to the ultimate application of the proposed model in a real-life prognosis process. 相似文献
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Katarina Vojisavljević Goran Branković Tatjana Srećković Aleksander Rečnik Zorica Branković 《Journal of the European Ceramic Society》2010,30(2):485-488
Ultrathin PZT film was prepared using a chemical solution deposition method from polymeric citrate precursors. The PZT solution was spin-coated on an amorphous silica layer formed on a Si(1 0 0) substrate. The films were thermally treated from the substrate side with a low heating rate (1°/min) up to 700 °C and finally annealed for 10 h. Ultrathin PZT films without microstructural instability were prepared in spite of high temperature and long annealing time. AFM and HRTEM investigations revealed the formation of a well-developed dense microstructure consisting of spherical crystallites (4–7 nm). Low roughness (2.2 nm) of a ~26 nm thick layer was obtained for a two-layered PZT film. The grazing incidence X-ray diffraction (GIXRD) measurements confirmed the polycrystalline structure of ultrathin PZT films. Also, GIXRD and electron energy dispersive X-ray (EDS) analysis showed that compositional variations were smaller than expected, in spite of the long annealing time. 相似文献
26.
27.
Jan Blaszczak Jolanta Zimoch Wieslaw Hreczuch Aleksander Matuszewski Jan Szymanowski 《Journal of surfactants and detergents》1999,2(1):29-37
Surface and interfacial tension isotherms for narrow-range distribution ALFOL 1214 alcohol oxyethylates were determined and
compared with those obtained for broad-range alcohol oxyethylates. Various adsorption parameters were estimated. The effectiveness
of surface tension reduction decreases when the length of polyoxyethylene hydrophile increases. Micellization is observed
at log cmc ranging from −4.7 to −3.3. Effects of the length and distribution of the polyoxyethylene chain on cmc are very
small. A minimum of A
min/N
av
0.5 is obtained for N
av=8, where A
min and N
av denote the minimum interfacial area occupied by a statistical molecule at the saturated interface and the average degree
of oxyethylation, respectively. The interface becomes saturated at pC
20=−5.61±0.35, where pC
20 denotes the logarithm of concentration required to obtain the surface pressure equal to 20 mNm−1. The highest and lowest values of the surface excess at saturation and the free energy of adsorption, respectively, are obtained
for an average degree of oxyethylation equal to 8. Parameters are correlated with the average degree of oxyethylation and
the oxyethylene chain distribution parameter according to empirical second-order polynomials. Small differences in adsorption
abilities at the water/air interface are only observed for narrow- and broad-range distributed oxyethylates. The differences
become important for adsorption at the hexadecane/water interface. The lowest values of interfacial tension are obtained for
narrow-range oxyethylates with N
av=7 and 8. The Krefeld fabric detergency tests indicated that the best detergency was observed for alcohol oxyethylates with
N
av=5–7. Narrow-range oxyethylates exhibit somewhat better washing abilities than the broad-range products. No relationship between
detergency of alcohol oxyethylates and their abilities to adsorb at the water/air and water/hydrocarbon interfaces is observed. 相似文献
28.
29.
Malgorzata Nogala-Kalucka Magdalena Rudzinska Ryszard Zadernowski Aleksander Siger Inga Krzyzostaniak 《Journal of the American Oil Chemists' Society》2010,87(12):1481-1487
The lipophilic and hydrophilic antioxidants were evaluated in eight plants: safflower (Carthamus tinctorius), viper’s bugloss (Echium vulgare), quince (Cydonia vulgaris), evening primrose (Oenothera biennis), rose mosqueta (Rosa affinis rubiginosa), black seed (Nigella sativa), sea buckthorn (Hippophae rhamnoides) and borage (Borago officinales). The highest amounts of tocopherols were contained in seeds of borage and sea buckthorn (66.9 mg/100 g and 45.9 mg/100 g,
respectively). The sea buckthorn seed lipids had the highest amount of total sterols (10.4 mg/g of lipids). The predominant
form was campesterol. Sitosterol was the major sterol in the lipids of other tested seeds. The content of phenolic compounds
ranged from 736.5 mg/100 g dry matter (d.m.) (evening primrose) to 74.8 mg/100 g d.m. (safflower). The highest antioxidant
activity, expressed in % scavenged DPPH· free radicals, was observed for evening primrose (91.2%), while the lowest for safflower
(36.2%). The correlation coefficient between the level of phenolic compounds and antioxidant activity was 0.53. 相似文献
30.
A process of plasma‐initiated grafting of acrylic acid on commercial porous polypropylene membrane was studied. The influence of parameters of the plasma (power, gas pressure, time plasma‐sample distance, sample arrangement) and grafting (solvent composition, monomer concentration, time, inhibitor presence) on the degree of grafting, amount of homopolymer produced and surface electrical resistance was determined. A degree of grafting up to 18 mmol/g was obtained, which resulted in sample resistance as low as 30 mΩ cm2. The molecular weight of AAc homopolymer that can be assumed as equal to the MW of grafted chains, ranged from 25,000 to 50,000,000 da. SEM and water permeability measurements show that grafting causes filling of the pores, which, however, does not stop K+ ions from penetrating the membrane. The performance of nickel‐cadmium cells with acrylic acid grafted membranes as separator is also presented. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献