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81.
An existing extensive database on the isothermal and thermomechanical fatigue behaviour of high-temperature titanium alloy
EVII 834 and dispersoid-strengthened aluminum alloy X8019 in SiC particle-reinforced as well as unreinv conditions was used
to evaluate both the adaptability of fracture mechanics approaches to TMF and the resulting predictive capabilities of determining
material life by crack propagation consideration. Selection of the correct microstructural concepts was emphasised and these
concepts were, then adjusted by using data from independent experiments in order to avoid any sort of fitting. It is shown
that the cyclic /-integral (δJeff concept) is suitable to predict the cyclic lifetime for conditions where the total crack propagation rate is approximately
identical to pure fatigue crack growth velocity. In the case that crack propagation is strongly affected by creep, the creep-fatigue
damage parameter δCF introduced by Riedel can be successfully applied. If environmental effects are very pronounced, the accelerating influence
of corrosion on fatigue crack propagation can no longer implicitly be taken into account in the fatigue crack growth law.
Instead, a linear combination of the crack growth rate contributions from plain fatigue (determined in vacuum) and from environmental
attack is assumed and found to yield a satisfactory prediction, if the relevant corrosion process is taken into account. 相似文献
82.
The photonic quantum ring (PQR) laser is a three dimensional whispering gallery (WG) mode laser and has anomalous quantum wire properties, such as microampere to nanoampere range threshold currents and √T‐dependent thermal red shifts. We observed uniform bottom emissions from a 1‐kb smart pixel chip of a 32×32 InGaAs PQR laser array flip‐chip bonded to a 0.35 µm CMOS‐based PQR laser driver. The PQR‐CMOS smart pixel array, now operating at 30 MHz, will be improved to the GHz frequency range through device and circuit optimization. 相似文献
83.
Sungmoon Jung Jamshid Ghaboussi Soon-Duck Kwon 《Canadian Metallurgical Quarterly》2004,130(11):1356-1364
A new method of estimating flutter derivatives using artificial neural networks is proposed. Unlike other computational fluid dynamics based numerical analyses, the proposed method estimates flutter derivatives utilizing previously measured experimental data. One of the advantages of the neural networks approach is that they can approximate a function of many dimensions. An efficient method has been developed to quantify the geometry of deck sections for neural network input. The output of the neural network is flutter derivatives. The flutter derivatives estimation network, which has been trained by the proposed methodology, is tested both for training sets and novel testing sets. The network shows reasonable performance for the novel sets, as well as outstanding performance for the training sets. Two variations of the proposed network are also presented, along with their estimation capability. The paper shows the potential of applying neural networks to wind force approximations. 相似文献
84.
85.
An analog front‐end circuit for ISO/IEC 14443‐compatible radio frequency identification (RFID) interrogators was designed and fabricated by using a 0.25 µm double‐poly CMOS process. The fabricated chip was operated using a 3.3 Volt single‐voltage supply. The results of this work could be provided as reusable IPs in the form of hard or firm IPs for designing single‐chip ISO/IEC 14443‐compatible RFID interrogators. 相似文献
86.
The gas flow sputter technique was invented a few years ago particularly for the inexpensive fabrication of sophisticated ceramic layers. Meanwhile, it has matured and become increasingly powerful. Today it is on the verge of being applied in industrial fabrication processes. The present article gives an overview over the method, its characteristics and the numerous applications. 相似文献
87.
Ln2B2O7 (Ln=Sm, Eu, Gd and Tb; B=Zr or Ti) with pyrochlore structure was prepared by sol–gel method for the high-temperature catalytic combustion. The crystal structure of Ln2B2O7 was identified by XRD and their surface area was about 4 m2/g after calcinations at 1200 °C. Catalytic activity of methane combustion was observed for Ln2Zr2O7 series and the best catalyst was Sm2Zr2O7. Its relative reaction rate per unit surface area at 600 °C was 2 cm3/m2 min, which was twice higher than that of Mn-substituted Sr hexaaluminate. From surface analysis by XPS, the low binding energy of each Ln element of Ln2Zr2O7 compared to that of Ln2Ti2O7, gave the catalytic activity of methane combustion. 相似文献
88.
JaeHyunKim JounHoLee JiChulLim ChangHoonLee MooHyoungSong JuYeonYoon HeeDongChoi JeomJaeKim ChangHoOh SangDeogYeo 李路海 《现代显示》2004,31(5):31-33
薄膜晶体管液晶电视(TFT-LCD TV)因为具有薄、轻、紧凑和可随意放置的特点,已经占据了大部分电视机市场。除了这些物理特性以外,最重要的特性是已具有了良好像质的对比度。为了将对比度提高到1:600以上,对偏振片膜、背光源板、滤色片树脂、电极锥角和摩擦条件等都进行了研究。优化的背光板组合,光滑的电极锥角和摩擦方法的控制是提高对比度的主要控制因素。应用新开发的滤色片树脂,对获得高对比度最为有效。 相似文献
89.
90.
This paper presents the model of a k-out-of-n: G system with common mode outages. The objective is to analytically derive the mean operating mode between failures for a non-repairable component system. The average system failure time and the system availability are also considered. Then, the model is extended to a system with repairable components and unrestricted repair, in which service times are exponentially distributed. 相似文献