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991.
采用Gleeble-3500热模拟试验机对30CrNi3MoV钢进行单向热压缩试验,研究了其在变形温度950~1150 ℃、应变速率0.01~10 s-1的热变形行为,构建了应变补偿型流变应力本构方程,并绘制出该钢的热加工图。结果表明,30CrNi3MoV钢真应力-真应变曲线有3种不同特征:高温小应变速率时,表现为典型的动态再结晶过程;低温小应变速率时,曲线为动态回复特征;应变速率较大时,应力随应变的增大而增大,无明显的峰值应力。采用5次多项式拟合构建的应变耦合流变应力本构方程具有高的精确度,采用该方程获得的预测值与试验值的平均相对误差为3.2%,相关性系数R值为0.993。从热加工图中得到试验钢最佳的热加工工艺参数范围是:变形温度为1020~1150 ℃、应变速率为0.03~0.35 s-1。 相似文献
992.
993.
B. Wu P.L. Chu 《Photonics Technology Letters, IEEE》1996,8(2):230-232
We report an experimental investigation of the fast optical switching in a Sm/sup 3+/-doped fiber. We discovered that this fiber can effect a fast switching speed less than 5 ns. However, the required switching power is 472 W with pulsewidth 10 ns. 相似文献
994.
995.
In this article, we study the effects of network topology and load balancing on the performance of a new parallel algorithm for solving triangular systems of linear equations on distributed-memory message-passing multiprocessors. The proposed algorithm employs novel runtime data mapping and workload redistribution methods on a communication network which is configured as a toroidal mesh. A fully parameterized theoretical model is used to predict communication behaviors of the proposed algorithm relevant to load balancing, and the analytical performance results correctly determine the optimal dimensions of the toroidal mesh, which vary with the problem size, the number of available processors, and the hardware parameters of the machine. Further enhancement to the proposed algorithm is then achieved through redistributing the arithmetic workload at runtime. Our FORTRAN implementation of the proposed algorithm as well as its enhanced version has been tested on an Intel iPSC/2 hypercube, and the same code is also suitable for executing the algorithm on the iPSC/860 hypercube and the Intel Paragon mesh multiprocessor. The actual timing results support our theoretical findings, and they both confirm the very significant impact a network topology chosen at runtime can have on the computational load distribution, the communication behaviors and the overall performance of parallel algorithms. 相似文献
996.
In our previous study (Xue P, Yu TX, Shu E. International Journal of Materials Processing Technology 1999; 89-90:65-71.), based on the membrane theory of shells of revolution and an energy method a mechanics model and corresponding analytical procedure have been proposed to predict springback of circular and square metal sheets after a double-curvature forming operation. The strain hardening of the material is incorporated into the mechanics model. In the present paper, the method is extended to the cases, in which bending effect, as well as bending-and-unbending effect are taken into account. It is shown that the procedure developed is capable of quantitatively predicting the strain distribution and springback of metal sheets after axisymmetric stamping with a relatively minor effort of calculation and a good accuracy. The effect of stretching force applied at the edge of the plate on springback is also considered. Excellent agreement is found between the theoretical prediction of springback and experiment results. 相似文献
997.
Woo‐Hee Kim Min‐Kyu Kim Il‐Kwon Oh Wan Joo Maeng Taehoon Cheon Soo‐Hyun Kim Atif Noori David Thompson Schubert Chu Hyungjun Kim 《Journal of the American Ceramic Society》2014,97(4):1164-1169
Films of CeO2 were deposited by atomic layer deposition (ALD) using a Ce(mmp)4 [mmp = 1‐methoxy‐2‐methyl‐2‐propanolate] precursor and H2O reactant. The growth characteristics and film properties of ALD CeO2 were investigated. The ALD CeO2 process produced highly pure, stoichiometric films with polycrystalline cubic phases. Using the ALD CeO2 process, the effects of Ce doping into an HfO2 gate dielectric were systematically investigated. Regardless of Ce/(Ce + Hf) composition, all ALD CexHf1?xO2 films exhibited constant growth rates of approximately 1.3 Å/cycle, which is essentially identical to the ALD HfO2 growth rates. After high‐temperature vacuum annealing at 900°C, it was verified, based on X‐ray diffraction and high‐resolution cross‐sectional transmission electron microscopy results, that all samples with various Ce/(Ce + Hf) compositions were transformed from nanocrystalline to stabilized cubic or tetragonal HfO2 phases. In addition, the dielectric constant of the CexHf1?xO2 films significantly increased, depending on the Ce doping content. The maximum dielectric constant value was found to be nearly 39 for the Ce/(Ce + Hf) concentration of ~11%. 相似文献
998.
Metal oxide nanosheets have potential applications in novel nanoelectronics as nanocrystal building blocks. In this work, the devices with a structure of Au/p-type Co3O4 nanosheets/indium tin oxide/glass having bipolar resistive switching characteristics were successfully fabricated. The experimental results demonstrate that the device have stable high/low resistance ratio that is greater than 25, endurance performance more than 200 cycles, and data retention more than 10,000 s. Such a superior performance of the as-fabricated device could be explained by the bulk film and Co3O4/indium tin oxide glass substrate interface effect. 相似文献
999.
Wei-Cheng Tang Yi-Che Su Yun-Shan Huang Ya-Tin Yu Hsin-Lung Chen I-Ming Chu 《应用聚合物科学杂志》2019,136(39):48003
While perfluoroalkyl acids (PFAAs), also known as C8s, are used extensively in textile repellent coatings, concerns have arisen for their carcinogenicity and hazardous effects on the environment. In this study, a novel water-based, nonfluoro, and nanobrush textile repelling agent was prepared by conventional sol–gel chemistry using amorphous fumed silica and n-octyltriethoxysilane as the starting materials. Minimal interaction between the designed repelling agent and marketed water-based resins was confirmed using linear viscosity region (LVR) analysis and asymmetric-flow field-flow fractionation (AF4), suggesting the self-stratification potential of the repelling agent. More specifically, the repelling agent exhibited excellent compatibility and self-stratifying ability with a force-emulsified acrylic-based resin, affording a water contact angle of 104.3° when incorporated at 7% solid content. Performance tests carried out on thermoplastic polyurethane (TPU) revealed excellent adhesion (100/100) of a final formulation, and a significant increase in water contact angle from 80.1° to 103.8° after treatment. In addition, the fouling area after the removal of a submerged sample from a mixture of slurry, polymer, and oil decreased from 48 to 1% when the repelling agent was added. Moreover, the sludge-fouling property remained unchanged after 1000 cycles of abrasion. These findings demonstrate the potential of the described nonfluoro, nanobrush repelling agent as an environmentally safe alternative for use with commercial resins, in turn realizing a fully water-based hydrophobic coating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48003. 相似文献
1000.
Li-Huei Lin Hawn-Chung Chu Keng-Ming Chen Shih-Chieh Chen 《Journal of surfactants and detergents》2019,22(1):73-83
In this study, propylene glycol-based glycosides were obtained using an acetalization reaction in which glucose was first reacted with propylene glycol. Subsequently, the propylene glycol glycoside was reacted with alkyl glycidyl ether of varying carbon chain lengths (i.e., 08-G, 10-G, 12-G, 14-G, and 16-G) to synthesize a series of glucose-based biodegradable surfactants. The experimental results show that the surface activity of the C8–C12 glucose-based surfactants increases with the carbon chain length. However, the surface activity of the C14–C16 glucose-based surfactants decreased as the carbon chain length increased. Among all the surfactants, the C12 glucose-based surfactant exhibited the most efficient emulsification ability, lowest surface tension, lowest fluorescence intensity, highest zeta potential, and good emulsification stability. The glucose-based surfactants were used as additives in natural plant dyes made from turmeric or henna to dye wool fabrics. Higher color strengths were observed in the C14 glucose-based surfactant. 相似文献