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41.
Abstract Using some properties of matrix measures and matrix's spectral radius, a new stability criterion for a linear time‐delay system is derived. This result is also extended to interval time‐delay systems. 相似文献
42.
In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN) epilayers on c- and a-axis sapphire
substrates and then used the nanoscratch technique and atomic force microscopy (AFM) to determine the nanotribological behavior
and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena
occurred on both sides of the scratches formed on the GaN epilayers. It is suggested that cracking dominates in the case of
GaN epilayers while ploughing during the process of scratching; the appearances of the scratched surfaces were significantly
different for the GaN epilayers on the c- and a-axis sapphire substrates. In addition, compared to the c-axis substrate, we
obtained higher values of the coefficient of friction (μ) and deeper penetration of the scratches on the GaN a-axis sapphire
sample when we set the ramped force at 4,000 μN. This discrepancy suggests that GaN epilayers grown on c-axis sapphire have
higher shear resistances than those formed on a-axis sapphire. The occurrence of pile-up events indicates that the generation
and motion of individual dislocation, which we measured under the sites of critical brittle transitions of the scratch track,
resulted in ductile and/or brittle properties as a result of the deformed and strain-hardened lattice structure. 相似文献
43.
This study compared the inhibitory activity of α-amylase inhibitor (αAI) extracted from common bean (Phaseolus vulgaris L.) variety Hwachia, its nine mutants and two introduced varieties by using three-phase partitioning (TPP). A commercially prepared Phase 2 was also used to serve as a comparative reference. The optimal purification parameters for TPP were 30% saturation ammonium sulphate and pH 5.25. Considerable variations were detected in αAI content, total inhibitory activity and specific inhibitory activity of αAI purified from different common beans. Mutant SA-05 had the αAI inhibitory activity of 6267 units g−1 dry seed weight, which was higher than Hwachia (5062 units g−1 dry seed weight) and Phase 2 (3200 units g−1 dry weight). Moreover, it had an extremely lower IC50 (0.40 μg) than Phase 2 (10.22 μg). Thus, the mutant SA-05 may be used as raw material in commercial preparation of αAI extracts for controlling appetite and energy intake. 相似文献
44.
Hsiao T. H. Chen T. C. Jeng S. L. Chung T. J. Tsay L. W. 《Journal of Materials Engineering and Performance》2016,25(10):4317-4325
Journal of Materials Engineering and Performance - Microstructures of the heat-affected zone (HAZ) of a Gr. 91 steel weld were simulated to evaluate their effects on the creep life of the weld at... 相似文献
45.
Shu‐Kai Yeh Chien‐Hsiung Huang Chi‐Chun Su Kuo‐Chung Cheng Tsu‐Huang Chuang Wen‐Jeng Guo Sea‐Fue Wang 《Polymer Engineering and Science》2013,53(10):2061-2072
In this study, polystyrene/nanographite nanocomposite foams were made by different compounding methods, such as direct compounding, pulverized sonication compounding, and in situ polymerization, to understand the effect of the process variables on the morphology of the nanocomposites and their foam. The foam was made by batch foaming using CO2 as the blowing agent. Various foaming pressures and temperatures were studied. The results indicated that the cell size decreased and the cell morphology was improved with the advanced dispersion of the nanoparticles. Among the three methods, the in situ polymerization method provided the best dispersion and the resulting nanocomposite foam had the finest cell size and the highest cell density. In addition, adding nanoparticles as a nucleating agent can make foams of similar cell size and cell density at a much lower foaming pressure. This result can be explained by the classical nucleation theory. This discovery could open up a newroute to produce microcellular foams at a low foaming pressure. POLYM. ENG. SCI., 53:2061–2072, 2013. © 2013 Society of Plastics Engineers 相似文献
46.
Huang Tien-Chi Jeng Yu-Lin Hsiao Kuo-Lun Tsai Bi-Rung 《Universal Access in the Information Society》2017,16(2):303-312
Universal Access in the Information Society - In many cases, classrooms seem to be functioning as well as ever, though the challenges and expectations have changed quite dramatically. This study... 相似文献
47.
Thermal behavior in a 180-deg turned channel with the perforation divider under rotational condition
Tzer-Ming Jeng Sheng-Chung Tzeng Jian-Hong Chang 《International Communications in Heat and Mass Transfer》2012
This study provided a new configuration of the 180-deg turned channel with a perforation divider. The perforations cross the divider let the coolant at the first duct to bypass into the second duct early, preventing from the local high temperature at the downstream zone. Additionally, the perforation-induced disturbing flow should enhance the total heat transfer. This work experimentally investigated the heat transfer behaviors of such system under the rotational condition. The results indicated that the perforation would reduce the raise of the local heat transfer at the turned region. Besides, the rotation would obviously influence the local heat transfer on the leading and trailing surfaces. Furthermore, the effect of rotation on the total heat transfer was insignificant. Finally, the perforation system with the relative perforation diameter d/Dh = 2/4 had the similar total heat-transfer capacity with that without perforation; the total heat-transfer capacity of the perforation system with d/Dh = 1/4 was around 20% higher than the non-perforation one. 相似文献
48.
In this paper, we develop a method to lower the computational complexity of pairwise nearest neighbor (PNN) algorithm. Our approach determines a set of candidate clusters being updated after each cluster merge. If the updating process is required for some of these clusters, k-nearest neighbors are found for them. The number of distance calculations for our method is O(N2), where N is the number of data points. To further reduce the computational complexity of the proposed algorithm, some available fast search approaches are used. Compared to available approaches, our proposed algorithm can reduce the computing time and number of distance calculations significantly. Compared to FPNN, our method can reduce the computing time by a factor of about 26.8 for the data set from a real image. Compared with PMLFPNN, our approach can reduce the computing time by a factor of about 3.8 for the same data set. 相似文献
49.
Shyy's multiple one-dimensional adaptive grid method is modified to improve the grid skewness. A test problem of steady isotropic heat conduction illustrates that both the grid distortion and the accuracy of temperature distribution are improved significantly. 相似文献
50.
Hung-Chuan Mai Tsung-Eong Hsieh Shiang-Yao Jeng Chong-Ming Chen Jen-Long Wang 《Materials Chemistry and Physics》2009,113(2-3):680-684
Optimum structure for HD-DVD optical disks containing Al–Ti/Si bi-layer recording system was identified by reflectivity simulation and dynamic test of disk samples. For the disk sample with optimized structure, the maximum partial response signal-to-noise ratio (PRSNR) of 19.1 dB, minimum simulated bit error rate (sbER) of 1.7 × 10?7 and modulation >0.6 were achieved at the writing power (Pw) = 11.2 mW. Transmission electron microscopy (TEM) revealed that the polycrystalline granular clusters constitute the recording marks. Subsequent analyses evidenced that element mixing/alloy reactions occur in between Si and Al–Ti layers and the formation of Al3.21Si0.47 crystalline phase is responsible for the signal recording in the disk samples. 相似文献