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101.
102.
Przemysław Fima Janusz Pstruś Tomasz Gancarz 《Journal of Materials Engineering and Performance》2014,23(5):1530-1535
Wetting of Cu and Al pads by Sn-Zn eutectic-based alloys with 0.5, 1, and 1.5 wt.% of Cu was studied at 250 °C, in the presence of ALU33® flux, with wetting times of 15, 30, 60, and 180 s, respectively. With increasing wetting time the wetting angle decreases only slightly and the angles on Cu pads are higher than those on Al pads. Selected, solidified solder-pad couples were cross-sectioned and subjected to SEM-EDS study of the interfacial microstructure. The results revealed that the microstructure of the SnZnCu/Cu interface is much different from SnZnCu/Al interface. In the first case continuous interlayers are observed while in the latter case there is no interlayer but the alloy dissolves the substrate along grain boundaries. 相似文献
103.
The transducer applied in sensors and measurement systems often have non-linear characteristics, which may depend on additional factors as temperature, humidity gases flow, etc. Therefore, it is important to find the function describing the dependence between input and output values of a transducer which takes into account all the influencing factors. This paper shows a method which, basing on measured data, allows to establish a multi-variable transducer transfer function. 相似文献
104.
The present paper describes numerical modelling of the radiative heat transfer process in the module chamber of an internal indirect reforming-type SOFC. The ability to do internal reforming is one of the characteristics of high-temperature fuel cells, SOFC. As in any high-temperature system, radiative heat transfer is important. In this article, heat transfer between the fuel reformer surface and all other surfaces facing the reformer surfaces is modelled. Governing equations for radiative heat transfer are described using Hottel's zone method. The resulting radiation–conduction conjugate heat transfer problems are numerically solved with a combination of Gauss–Seidel and Newton–Raphson methods. The steam reforming reaction occurring inside the fuel reformer is described using Achenbach model. The obtained results indicate that, for the development of effective indirect internal reforming, the position of the reformer in the module chamber and emissivity of the surfaces of the reformer, cell and other elements in the SOFC module all play a key role. 相似文献
105.
Bujnicki Janusz M.; Rotkiewicz Piotr; Kolinski Andrzej; Rychlewski Leszek 《Protein engineering, design & selection : PEDS》2001,14(10):717-721
Using a recent version of the SICHO algorithm for in silicoprotein folding, we made a blind prediction of the tertiarystructure of the N-terminal, independently folded, catalyticdomain (CD) of the I-TevI homing endonuclease, a representativeof the GIYYIG superfamily of homing endonucleases. Thesecondary structure of the I-TevI CD has been determined usingNMR spectroscopy, but computational sequence analysis failedto detect any protein of known tertiary structure related tothe GIYYIG nucleases (Kowalski et al., Nucleic AcidsRes., 1999, 27, 21152125). To provide further insightinto the structurefunction relationships of all GIYYIGsuperfamily members, including the recently described subfamilyof type II restriction enzymes (Bujnicki et al., Trends Biochem.Sci., 2000, 26, 911), we incorporated the experimentallydetermined and predicted secondary and tertiary restraints ina reduced (side chain only) protein model, which was minimizedby Monte Carlo dynamics and simulated annealing. The subsequentlyelaborated full atomic model of the I-TevI CD allows the availableexperimental data to be put into a structural context and suggeststhat the GIYYIG domain may dimerize in order to bringtogether the conserved residues of the active site. 相似文献
106.
Defect Chemistry of (La,Sr)MnO3 总被引:1,自引:0,他引:1
Defect-disorder models are derived for undoped and strontium-doped LaMnO3 . A random-defect model and a cluster-defect model are both considered within the regimes that correspond to oxygen deficit and oxygen excess. The models are constructed based on the experimental nonstoichiometry data that was reported by previous researchers. According to both models, the addition of strontium leads to an increase of the concentration of electron holes and oxygen nonstoichiometry. The defect clusters that are predicted by the cluster model have a marked concentration only at very low oxygen partial pressures. Both models are verified against the electrical-conductivity data. A good agreement between the random-defect model and the experimental data is shown. 相似文献
107.
For Pb-free soldering materials, two main substitutes are currently being considered, consisting of Sn–Ag and Sn–Ag–Cu eutectics,
both with melting points higher than that of the Sn–Pb eutectic. Therefore, both will require higher soldering temperatures
for industrial applications. Also, both eutectics have a higher surface tension than the Sn–Pb eutectic, requiring wettability
studies on adding Bi, Sb, and In to the eutectics to decrease the melting points and surface tension. The experimental results
for the surface tension were compared with thermodynamic modeling by Butler’s method and were used to create the SURDAT database,
which also includes densities for pure metals, binary, ternary, quaternary, and quinary alloys. To model the surface tension,
excess Gibbs energies of the molten components were taken from the ADAMIS database. For the case of the Ag–Sn system, enthalpies
of formation of Ag3Sn from solution calorimetry were used for checking optimized thermodynamic parameters. In the study of Sn–Ag–Cu–Bi–Sb liquid
alloys, the range of possible Bi compositions for practical applications has been used to formulate a generalized metric of
wettability, which was checked by measurements of the influence of In on the Sn–Ag–Cu system. 相似文献
108.
Ewa Cieślik Teresa Leszczyńska Agnieszka Filipiak-Florkiewicz Elżbieta Sikora Paweł M. Pisulewski 《Food chemistry》2007,105(3):976-981
Effects of blanching, boiling and freezing of selected cruciferous vegetables (Brussels sprouts, white and green cauliflower, broccoli, and curly cale) on their glucosinolate (GLS) contents were determined. It was found that blanching and cooking of the vegetables led to considerable (P < 0.05) losses of total GLS, from 2.7 to 30.0% and from 35.3 to 72.4%, respectively. No systematic changes in total GLS were found in the vegetables that were blanched and frozen for 48 h. In addition, the highest concentration of cancer-protective compounds, such as aliphatic and indole GLS, were found in Brussels sprouts (sinigrin and glucobrassicin) and in broccoli (glucoraphanin). 相似文献
109.
Shanju Zhang Lingbo Zhu Marilyn L. Minus Han Gi Chae Sudhakar Jagannathan Ching-Ping Wong Janusz Kowalik Luke B. Roberson Satish Kumar 《Journal of Materials Science》2008,43(13):4356-4362
We report continuous carbon nanotube (CNT) fibers and yarns dry-drawn directly from water-assisted chemical vapor deposition
(CVD) grown forests with about 1-mm height. As-drawn CNT fibers exist as aerogel and can be transformed into more compact
fibers through twisting or densification with a volatile organic liquid. CNT fibers are characterized by scanning electron
microscopy, X-ray photoelectron spectroscopy, Raman microscopy, and wide-angle X-ray diffraction. Mechanical properties and
electrical conductivity of the post-treated CNT fibers are investigated. The resulting fibers show the work of rupture of
30 J/g and DC electrical conductivity of 5.0 × 104 S/m. 相似文献
110.
This paper presents a novel approach to the reconstruction of images from nonuniformly spaced samples. This problem is often encountered in digital image processing applications. Nonrecursive video coding with motion compensation, spatiotemporal interpolation of video sequences, and generation of new views in multicamera systems are three possible applications. We propose a new reconstruction algorithm based on a spline model for images. We use regularization, since this is an ill-posed inverse problem. We minimize a cost function composed of two terms: one related to the approximation error and the other related to the smoothness of the modeling function. All the processing is carried out in the space of spline coefficients; this space is discrete, although the problem itself is of a continuous nature. The coefficients of regularization and approximation filters are computed exactly by using the explicit expressions of B-spline functions in the time domain. The regularization is carried out locally, while the computation of the regularization factor accounts for the structure of the nonuniform sampling grid. The linear system of equations obtained is solved iteratively. Our results show a very good performance in motion-compensated interpolation applications. 相似文献