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91.
Tomer A. Goldin L. Kuflik T. Kimchi E. Schach S.R. 《IEEE transactions on pattern analysis and machine intelligence》2004,30(9):601-612
We propose a model that enables software developers to systematically evaluate and compare all possible alternative reuse scenarios. The model supports the clear identification of the basic operations involved and associates a cost component with each basic operation in a focused and precise way. The model is a practical tool that assists developers to weigh and evaluate different reuse scenarios, based on accumulated organizational data, and then to decide which option to select in a given situation. The model is currently being used at six different companies for cost-benefit analysis of alternative reuse scenarios; we give a case study that illustrates how it has been used in practice. 相似文献
92.
T. Connolley M. J. Starink P. A. S. Reed 《Metallurgical and Materials Transactions A》2004,35(3):771-783
Notches were machined in specimens of INCONEL 718 by a broaching process, where differing broaching runs led to differing
extents of subsurface deformation and surface roughness. Fatigue tests were carried out at 600 °C with a trapezoidal loading
waveform at 0.25 Hz. The broaching process that led to the more severe subsurface deformation (but lower surface roughness)
showed the worst fatigue performance. Analysis of total strain amplitude in the notch root with the aid of an elastoplastic
finite-element (FE) model showed that the work hardening related to the subsurface deformation caused by the different broaching
can account for the difference in fatigue lives. Differences in initiation and growth behavior were seen for the two broached
finishes as well as for broached and subsequently polished samples. These differences are discussed in terms of a change in
crack growth initiation and growth mechanisms due to the presence of the work-hardened layer. 相似文献
93.
Thermal Transformations of an Aluminoborophosphate Binder 总被引:1,自引:0,他引:1
Thermal transformations of a commercial aluminoborophosphate binder are studied in a broad temperature range by optical microscopy, x-ray diffraction, IR spectroscopy, and thermal analysis. The introduction of B2O3 reduces the temperature of phosphate polycondensation, enhances the stability of cyclometaphosphates in a broad temperature range (180–1100°C), and reduces the stability of hydrogen phosphates. 相似文献
94.
Visualizing multivariate functions, data, and distributions 总被引:1,自引:0,他引:1
95.
The oxidation of chloro-5-10,15,20-tetramesitylporphyrinotoiron(III) with peroxyacids affords a reactive oxoiron(IV)-porphyrin cation radical species 2. The characterization of 2 and its oxochromium analogs 3, 4 and 5 are reviewed. The nature of reactive oxochromium species derived from chromyl reagents is also reviewed. The oxidation of triphenylphosphine by CrOTPP (11), CrOTTP (13) and CrOTMP (14) is described. Variations in the rate constants indicate that steric factors affect the rate of oxygen atom transfer. Activation parameters for the oxidation of triphenylphosphine by 14 are ΔH≠ = 6.96 kcal/mol and ΔS≠ = −39 eu. The oxidation of t-butylphenylcarbinol (18) by CrOTPP gave predominantly benzaldehyde via carbon—carbon bond cleavage while the chromium(III) porphyrin-catalyzed oxidation of 18 by iodosylbenzene afforded t-butylphenylketone. 相似文献
96.
Paul I. Dalven James R. Hildebrandt Abraham Shamir Anthony J. Laccetti Leonard T. Hodgins Harry P. Gregor 《应用聚合物科学杂志》1985,30(3):1113-1132
Various high molecular weight copolymers of acrylonitrile and a vinyl comonomer containing an aryl amine, a pyridine, or an aliphatic hydroxyl group were synthesized via slurry polymerization techniques so as to contain from 1 to 15 mol % functional comonomer. The comonomer content was quantitated by ultraviolet absorbance, base titration of acid polymer salts, and/or relative chemical reactivity with trichloro-s-triazine. Thin films were cast from copolymer solutions, coagulated into unsupported ultrafiltration membrances, and characterized with respect to both water permeability and pore size distribution. Analysis by size exclusion chromatography of the membrane permeate of a pool of dextran fractions yielded a continuous distribution curve for membrane pore size over the range 1.5 to 70 nm. The ultrafiltration membranes were used for protein immobilization after appropriate chemical activation. The three distinct types of functional copolymers gave comparable results for α-chymotrypsin, with protein weight loadings of 6–12% and 40–65% retention of enzymatic specific activity. 相似文献
97.
The objective of the study was to test the validity of an available backmix correlation in the low backmix regime required by multistage agitated contactors used as reactors. The correlation was found to be inapplicable, and new equation forms were developed to fit the new experimental data. Keys to low backmix rates are a small annular area around the shaft compared to the column cross-sectional area and an extended annular path length. 相似文献
98.
S. SATOH K. SUSA I. MATSUYAMA T. SUGANUMA 《Journal of the American Ceramic Society》1985,68(7):399-402
Formation and disappearance of closed pores in silica gel during sintering were experimentally detected using a light-scattering technique. The disappearance of closed pores is strongly influenced by the atmosphere in which the gel is sintered. 相似文献
99.
A method is developed, based on word-searching, which provides a rapid test for the statistical significance of DNA sequence similarities for use in databank searching. The method makes allowance for the lengths and dinucleotide compositions of the sequences being compared. A way is also described to calculate the power of the test, i.e. the probability of detecting a given similarity as being statistically significant. The effects on the power of the test of the scoring method, word length, sequence length, and sequence composition are examined. A novel scoring method is shown to be superior to the method currently used in most word-searching algorithms. 相似文献
100.