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31.
Tammy Ben-Yaacov Tommy Ive Chris G. Van de Walle Umesh K. Mishra James S. Speck Steven P. Denbaars 《Journal of Electronic Materials》2010,39(5):608-611
We investigated the properties of indium-doped zinc oxide layers grown by metalorganic chemical vapor deposition on semi-insulating
GaN(0001) templates. Specular and transparent films were grown with n-type carrier concentrations up to 1.82 × 1019 cm−3 as determined by Hall measurements, and all In-doped films had carrier concentrations significantly higher than that of a
comparable undoped film. For low In flows, the carrier concentration increased accordingly with trimethyl-indium (TMIn) flow
until a maximum carrier concentration of 1.82 × 1019 cm−3 was realized. For higher In flows, the carrier concentration decreased with increasing TMIn flow rate. Sheet resistance as
low as 185 Ω/sq was achieved for the In-doped films, which is a significant decrease from that of a comparable undoped ZnO
film. Our n-type doping studies show that In is an effective dopant for controlling the n-type conductivity of ZnO. 相似文献
32.
Zihong Liu Tommy E. Cousins John J. Lesko Elisa D. Sotelino 《Canadian Metallurgical Quarterly》2008,12(6):660-668
No appropriate provisions from either AASHTO Standard (2002) or AASHTO LRFD (2004) bridge design specifications are available for the design of fiber-reinforced polymer (FRP)-deck-on-steel-superstructure bridges. In this research, a parametric study using the finite-element method (FEM) is conducted to examine two design issues concerning the design of FRP-deck-on-steel-superstructure bridges, namely deck relative deflection and load distribution factor (LDF). Results show that the strip method specified in AASHTO LRFD specification as an approximate method of analysis, can also be applied to FRP decks as a practical method. However, different strip width equations have to be determined by either FEM or experimental methods for different types of FRP decks. In this study, one such equation has been derived for the Strongwell deck. In addition, both FEM results and experimental measurements show that the AASHTO LDF equations for glued laminated timber decks on steel stringers provide good estimations of LDF for FRP-deck-on-steel-superstructure bridges. Finally, it is found that the lever rule can be used as an appropriately conservative design method to predict the LDF of FRP-deck-on-steel-superstructure bridges. 相似文献
33.
Bernhard J.T. Kiely E. Washington G. 《Antennas and Propagation, IEEE Transactions on》2001,49(4):597-601
Experimental results are presented on a tunable mechanically actuated microstrip antenna with a parasitic director. A novel piezoelectric actuation system is used to vary dynamically the mechanical displacement of the parasitic element. The center frequency, bandwidth, and antenna gain change as a function of variable spacing between the driven and parasitic elements. In light of the experimental results, smart antenna tuning methods that use mechanical and electrical methods are compared and directions for future work are discussed 相似文献
34.
Kathryn M. L. Taylor-Pashow Thomas B. Peters Fernando F. Fondeur Aaron L. Washington II David T. Hobbs 《分离科学与技术》2015,50(18):2853-2865
The Defense Waste Processing Facility (DWPF), responsible for vitrifying high-level waste (HLW) at the Savannah River Site (SRS), is planning to introduce glycolic acid as a reductant during chemical conditioning of the waste prior to vitrification. A portion of this glycolic acid may be recycled back to the tank farm as sodium glycolate. Since glycolate can serve as a complexing agent for a variety of metallic ions, recent studies were performed to examine the effect of glycolate on the removal of Sr and actinides by monosodium titanate (MST) and modified MST (mMST) and the separation of Cs by the caustic-side solvent extraction (CSSX) process. 相似文献
35.
Rabby Xiao Yang Zhang Tommy Liu 《中国电子商情》2010,(9):54-55
在低于40纳米的超深亚微米VLSI设计中,时钟树网络在电路时序收敛、功耗、PVT变异容差和串扰噪声规避方面所起的作用要更重要得多。 相似文献
36.
65纳米设计时序收敛问题介绍时序收敛一直是当代ASIC设计物理实现的主要问题,特别是对于那些用于通信产品中的ASIC来说更是如此。我们有一项65纳米ASIC就是这种设计。它拥有2400万门数和4400万内存位,大部分逻辑将一直以400MHz 相似文献
37.
Barbara Geusens Mireille Van Gele Sien Braat Stefaan C. De Smedt Marc C. A. Stuart Tarl W. Prow Washington Sanchez Michael S. Roberts Niek N. Sanders Jo Lambert 《Advanced functional materials》2010,20(23):4077-4090
The extent to which nanoscale‐engineered systems cross intact human skin and can exert pharmacological effects in viable epidermis is controversial. This research seeks to develop a new lipid‐based nanosome that enables the effective delivery of siRNA into human skin. The major finding is that an ultraflexible siRNA‐containing nanosome—prepared using DOTAP, cholesterol, sodium cholate, and 30% ethanol—penetrates into the epidermis of freshly excised intact human skin and is able to enter into the keratinocytes. The nanosomes, called surfactant‐ethanol‐cholesterol‐osomes (SECosomes), show excellent size, surface charge, morphology, deformability, transfection efficiency, stability, and skin penetration capacity after complexation with siRNA. Importantly, these nanosomes have ideal characteristics for siRNA encapsulation, in that the siRNA is stable for at least 4 weeks, they enable highly efficient transfection of in vitro cultured cells, and are shown to transport siRNA delivery through intact human skin where changes in the keratinocyte cell state are demonstrated. It is concluded that increasing flexibility in nanosomes greatly enhances their ability to cross the intact human epidermal membrane and to unload their payload into targeted epidermal cells. 相似文献
38.
39.
Peter Loukopoulos Tommy G?rling Cecilia Jakobsson Satoshi Fujii 《Papers in Regional Science》2001,80(3):381-388
Books reviewed in this article:
Travel Demand Management and Public Policy. Erik Ferguson.
Self-Organization and the City. Juval Portugali (in collaboration with A. Alafasi, I. Benenson, H. Haken, I. Omer). Foreword by Herman Haken.
Growth, Employment and Migration in Southeast Asia: Structural Change in the Greater Mekong Countries. Prema-chandra Athukorala, Chris Manning, Piyasiri Wickramasekara. Cheltenham, U.K. 相似文献
Travel Demand Management and Public Policy. Erik Ferguson.
Self-Organization and the City. Juval Portugali (in collaboration with A. Alafasi, I. Benenson, H. Haken, I. Omer). Foreword by Herman Haken.
Growth, Employment and Migration in Southeast Asia: Structural Change in the Greater Mekong Countries. Prema-chandra Athukorala, Chris Manning, Piyasiri Wickramasekara. Cheltenham, U.K. 相似文献
40.
The morphological characteristics of the internal structure of poly (D,L-lactide) microspheres have been determined by stereological methods in two different formulations of microspheres, with different internal structures, prepared by using a double emulsion method. In one formulation the internal emulsion was produced by homogenisation at 3000 rpm, whilst the other was prepared at 11000 rpm. As expected the formulation prepared at the lower speed contained larger and more broadly distributed pores than that prepared at the higher speed. The porosity, pore size distribution and total internal surface area of the microspheres were obtained by stereological methods from electron microscopic measurements of the sectioned microspheres. It was found that whilst the porosity of the microspheres was 0.6 in both formulations, the preparation method gave rise to large differences in their pore size distribution characteristics. The pore size distribution was simulated by computer modelling to validate and compare alternative stereological algorithms. It was found that the Saltykov unfolding method predicts the measured pore size distribution more accurately than the Cruz-Orive unfolding method (at significance level alpha=0.1). This finding was attributed to the violation of one of the basic assumptions of the Cruz-Orive unfolding method. 相似文献