Phase transformation initiation

Segmented polyurethanes were synthesized by the reactions of poly(ε-caprolactone) (PCL)-diol and 1,6- hexamethylene diisocyanate through bulk polymerization without using solvent, initiator, or catalyst. Phase separation and hydrogen bond formation between hard segments or between hard and soft segments were examined by Fourier transform infrared spectroscopy (FTIR)-ATR and X-ray diffraction (XRD), while physical and mechanical properties were studied by atomic force microscope, differential scanning calorimeter, dynamic mechanical analysis, and tensile tester.

12p tudichquannguyet 29-11-2021 9 2   Download

Microstructural changes of an OPC cement paste after being exposed at various elevated temperatures and further rehydration have been evaluated using 29Si MAS-NMR. Thermogravimetry and XRD are also employed to complement the information. NMR studies of cement paste exposed to high temperatures demonstrate a progressive transformation of C-S-H gel that leads at 450◦C, to a modified C-S-H gel. For temperatures above 200◦C to a progressive formation of a new nesosilicate.

11p christian2605 10-10-2019 21 0   Download

In the quasi-linear theoxy of vibrations, the initial variable X is transformed either to the variables (a, b) or to the amplitude-phase ones ( r, 8) respectively by the formulae.

7p bautroibinhyen211 28-10-2018 19 1   Download

The aim of this paper is to examine the impact of the choice of plasticity theory-inspired model in the prediction of the shape of phase transformation domains. In this field a comparison is made between Huber-Von Mises based model and an another integrating the non-symmetry between tension and compression. The yield surface of phase transformation initiation for an homogeneous body under proportional biaxial loading is discussed.

9p thienthanquydu 17-10-2018 30 1   Download

STI policy issues identified during the transformation of the Korean system in the 2000s were: innovation-driven STI initiative, promotion of Korea’s technology market and technology companies, cultivation of university research, basic and fundamental research, facilitating industry and science partnerships.

12p jangni6 07-05-2018 37 1   Download

The Board on International Comparative Studies in Education (BICSE) was established by the National Research Council (NRC) in 1988 at the request of the U.S. Department of Education’s National Center for Education Statistics (NCES) and the U.S. National Science Foundation (NSF). Under its initial mandate, the board monitored U.S. participation in large-scale international comparative studies.

44p mnemosyne75 02-02-2013 55 6   Download

The idea of using ultrasonic waves in medical and engineering fields came from military applications of sound waves in sonar systems. Sokolov, Firestone, Simons, and several other researchers are among the ones who studied this high frequency kind of wave in the first half of twentieth century. Ultrasonic waves are defined as those with frequencies higher than 20 kHz. The constant development of data acquisition systems and probes seems to work, removing the upper limit of the wave frequency that can be acquired.

304p qsczaxewd 25-09-2012 91 12   Download

DWTs are constantly used to solve and treat more and more advanced problems. The DWT algorithms were initially based on the compactly supported conjugate quadrature filters (CQFs). However, a drawback in CQFs is due to the nonlinear phase effects such as spatial dislocations in multi-scale analysis. This is avoided in biorthogonal discrete wavelet transform (BDWT) algorithms, where the scaling and wavelet filters are symmetric and linear phase. The biorthogonal filters are usually constructed by a ladder-type network called lifting scheme.

340p lulanphuong 17-03-2012 117 20   Download

The discrete wavelet transform (DWT) algorithms have a firm position in processing of signals in several areas of research and industry. As DWT provides both octavescale frequency and spatial timing of the analyzed signal, it is constantly used to solve and treat more and more advanced problems. The DWT algorithms were initially based on the compactly supported conjugate quadrature filters (CQFs). However, a drawback in CQFs is due to the nonlinear phase effects such as spatial dislocations in multi-scale analysis.

308p lulanphuong 17-03-2012 119 20   Download