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91.
David L. Henann 《Journal of the mechanics and physics of solids》2010,58(11):1947-1962
Recent experiments in the literature show that micro/nano-scale features imprinted in a Pt-based metallic glass, Pt57.5Ni5.3Cu14.7P22.5, using thermoplastic forming at a temperature above its glass transition temperature, may be erased by subsequent annealing at a slightly higher temperature in the supercooled liquid region (Kumar and Schroers, 2008). The mechanism of shape-recovery is believed to be surface tension-driven viscous flow of the metallic glass. We have developed an elastic-viscoplastic constitutive theory for metallic glasses in the supercooled liquid temperature range at low strain rates, and we have used existing experimental data in the literature for Pt57.5Ni5.3Cu14.7P22.5 (Harmon et al., 2007) to estimate the material parameters appearing in our constitutive equations. We have implemented our constitutive model for the bulk response of the glass in a finite element program, and we have also developed a numerical scheme for calculating surface curvatures and incorporating surface tension effects in finite element simulations. By carrying out full three-dimensional finite-element simulations of the shape-recovery experiments of Kumar and Schroers (2008), and using the independently determined material parameters for the bulk glass, we estimate the surface tension of Pt57.5Ni5.3Cu14.7P22.5 at the temperature at which the shape-recovery experiments were conducted. Finally, with the material parameters for the underlying elastic-viscoplastic bulk response as well as a value for the surface tension of the Pt-based metallic glass fixed, we validate our simulation capability by comparing predictions from our numerical simulations of shape-recovery experiments of Berkovich nanoindents, against corresponding recent experimental results of Packard et al. (2009) who reported shape-recovery data of nanoindents on the same Pt-based metallic glass. 相似文献
92.
Point‐to‐Plane Nonhomogeneous Electric‐Field‐Induced Simultaneous Formation of Giant Unilamellar Vesicles (GUVs) and Lipid Tubes
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Chuntao Zhu Ying Zhang Yinan Wang Qingchuan Li Dr. Wei Mu Prof. Dr. Xiaojun Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):2906-2909
It is well‐known that homogeneous electric fields can be used to generate giant unilamellar vesicles (GUVs). Herein we report an interesting phenomenon of formation of GUVs and lipid tubes simultaneously using a nonhomogeneous electric field generated by point‐to‐plane electrodes. The underlying mechanism was analyzed using finite element analysis. The two forces play main roles, that is, the pulling force (F) to drag GUVs into lipid tubes induced by fluid flow, and the critical force (Fc) to prevent GUVs from deforming into lipid tubes induced by electric fields. In the center area underneath the needle electrode, the GUVs were found because F is less than Fc in that region, whereas in the edge area the lipid tubes were obtained because F is larger than Fc. The diffusion coefficient of lipid in the tubes was found to be 4.45 μm2 s?1 using a fluorescence recovery after photobleaching (FRAP) technique. The method demonstrated here is superior to conventional GUV or lipid tube fabrication methods, and has great potential in cell mimic or hollow material fabrication using GUVs and tubes as templates. 相似文献
93.
Hua-xing Chen Xiao-yan Wu Yi-gang Liu Jian-hua Bai Feng Zhao 《Journal of Dispersion Science and Technology》2016,37(4):486-495
A novel hydrophobically modified polyacrylamide p(AM/NaA/OP-10-AC/BOAM) was successfully synthesized via an aqueous micellar copolymerization method from acrylamide (AM), sodium acrylate (NaA), octylphenol polyoxyethylene acrylate (OP-10-AC), and small amounts of N-benzyl-N-octylacrylamide (BOAM), with the aim of investigating the copolymer's rheological behaviors under various conditions such as polymer concentration, shearing, temperature, and salinity. The copolymer was characterized by infrared spectroscopy, scanning electron microscopy, and atomic force microscope. Scanning electron micrographs show large aggregates in solution formed by the association from the hydrophobic groups of the copolymer. Compared with partially hydrolyzed polyacryamide (HPAM), the copolymer shows a much higher thickening capability and a much greater ability to resist shearing, heat, and salts. This good property of the copolymer is attributed to its three-dimensional dimensional network structure. According to the core flooding test, it can be obtained that oil recovery is enhanced about 4.3% by the copolymer flooding contrasted to the HPAM flooding in mid-low permeability cores under conditions of 1500 mg/L of polymers and 45°C. All the results prove that the copolymer has the capability of increasing oil recovery by improving waterflood sweep efficiency in high-salinity reservoirs. 相似文献
94.
Takenobu Kajikawa 《Journal of Electronic Materials》2009,38(7):1083-1088
The results of research and development in the Japanese national project “Development for Advanced Thermoelectric Conversion
Systems” are summarized, and the approaches to practical use of advanced thermoelectric modules and power generation systems
are presented. The 5-year national project was successfully completed in March 2007. Three kinds of high- efficiency cascaded
thermoelectric modules and two kinds of innovative Bi-Te thermoelectric modules were successfully developed. Heat cycle tests
for three types of modules were also completed. Moreover, four types of advanced thermoelectric power generation systems were
experimentally demonstrated for recovery of waste heat from the industrial and private sectors. In order to proceed further,
thermoelectric power generation systems using practical heat sources were followed after installation of the developed modules.
In parallel, various approaches for practical use by private companies, as well as plans for the next-phase project by the
National Institute of Advanced Industrial Science and Technology (AIST) and the Engineering Advancement Association (ENAA),
were also followed. The scenarios to proceed to the commercial phase of thermoelectric power generation are discussed on the
basis of the results of the national project. 相似文献
95.
计算机在现代军事装备中的作用日益重要,他在装备研制中所占工作量的比例越来越大。由于军用计算机的工作环境一般较恶劣,常容易引起计算机电源不稳定等问题,因此,如何保证计算机系统的可靠性已成为影响装备质量的关键因素。本文综合分析嵌入式系统中提高计算机容错性的常用技术,并给出采用软件恢复块实现掉电恢复的实例。 相似文献
97.
Yi-Ju Chen 《Microelectronics Journal》2006,37(9):985-992
This paper presents an integrated optical receiver that operates at 1 Gb/s in a standard 0.35 μm digital CMOS technology. The receiver consists of an integrated CMOS photodetector, a transimpedance amplifier (TIA) followed by a post-amplification stage and a dual-loop clock and data recovery (CDR) circuit. At a wavelength of 860 nm, the circuit requires an average light input power of −19.7 dBm to obtain a bit-error rate (BER) of 10−12. The complete receiver consumes a total power of approximately 155 mW from a 3.3-V supply. The core circuit area is 0.85×1.32 mm2. 相似文献
98.
冯登国 《信息安全与通信保密》1996,(4)
简述了基本的Nyberg-Rueppel认证方案和HMP认证方案,指出了LC认证方案是HMP认证方案的一个特例。 相似文献
99.
信元在 ATM 网内传输时,由于网内缓存的存在,造成了信元延时变化。信元延时变化对基于锁相环(PLL)的恒定比特率业务时钟的恢复有很大影响,即时钟的抖动和漂移比较明显。从而使这种基于 PLL 的CBR 业务时钟恢复方案在某些场合不能应用。本文提出了一种基于 PLL 的时钟恢复新方案,该方案可以明显地降低由于信元延时变化而造成的 CBR 业务时钟的抖动和漂移,同时不增加缓存的容量。 相似文献
100.
Mi-Ra Yoon Ju-Dong Shin Chang-Hyun Jeong Jun-Mo Jo Oh-Han Kang Sung-Un Kim 《Photonic Network Communications》2004,7(2):161-178
A virtual private network (VPN) over Internet has the benefit of being cost-effective and flexible. However, it has difficulties providing sufficient QoS and adequate transmission capacity for high bandwidth services. Given the increasing demand for high bandwidth Internet and the demand for QoS assurances in a VPN over Internet, IP/generalized multi-protocol label switching (GMPLS) based on a control plane combined with a high-bandwidth, dense-wavelength division multiplexing (DWDM) optical network is seen as a very favorable approach for realizing the future optical VPN (OVPN) over IP/GMPLS over DWDM. Within this architecture, providing QoS guaranteed multimedia services with a differentiated QoS guaranteed protocol framework with QoS recovery is one of the key issues to implement. Therefore, we suggest in this paper optical-label switched path (O-LSP) establishment and its QoS maintenance scheme based on differentiated optical QoS-service (DOQoS) classes. They are the key components for this DOQoS framework in assuring end-to-end QoS in an OVPN over IP/GMPLS over DWDM architecture. 相似文献