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941.
In this paper, we propose and analyze the outage probability of a two-way hybrid decode-and-amplify relaying scheme with relay selection for secondary spectrum access. In this scheme, a secondary network is co-located and uses the same spectrum as the primary network. The primary network is comprised of two primary terminals that attempt to transmit signals to one another; the secondary network is comprised of M secondary transmitter-receiver pairs (ST-SR). One of the secondary transmitters chosen to cooperate with the primary network uses a hybrid decode-and-amplify forward technique in order to relay primary and secondary signals. We derive expressions for the outage probability of the primary network as well as the secondary network over a Rayleigh fading channel. Simulation results are presented to verify theoretical analyses and to compare the performance of the proposed protocol to that of a two-way direct transmission protocol. 相似文献
942.
S. Y. Wu B. N. Tran F. Y. Davis C. L. Trent D. L. Edberg W. A. Geideman 《Integrated ferroelectrics》2013,141(3):281-291
Abstract Smart materials of lead-zirconate-titanate (PZT) piezoelectric ceramics have attracted attention in recent years for active vibration control, acoustic noise suppression, health monitoring and damage assessment. We at McDonnell Douglas Aerospace have been studying these ceramics for use as sensors and actuators in various space and aircraft structures. In this paper, we will report results of a recent study on active vibration control using monomorph PZT actuators. The experiments were performed on thin aluminum cantilever beams. Collocated and non-collocated sensors and actuators were employed. Two control techniques: the classical velocity feedback and adaptive feedback controls, were investigated. We have obtained significant damping and broadband vibration attenuation of greater than 30 dB using the classical control with the single-input single-output feedback approach. A 24 dB reduction has also been achieved using the adaptive control with the multiple-input single-output approach. Detailed experimental methods and results will be described. 相似文献
943.
Laboratory studies on the recovery of molybdenum from acid wash liquor, reported in Part 1 of this series of papers, identified the optimum process conditions for the production of high purity molybdenum trioxide and calcium molybdate. Pilot and plant scale operations were conducted as a result of the design developed during our laboratory studies.Molybdenum was selectively recovered from a wash liquor containing 10 g/L Mo via a 2-stage extraction using 10% v/v Alamine diluted in Anysol 150 diluent as extractant. The use of 10% v/v isodecanol (IDA) was found to enhance the extraction of molybdate from the wash liquor. The organic extractant liquor had to be scrubbed with water to remove the ammonium sulphate crud formed when ammonium hydroxide solution (20% w/v) was used to strip the molybdate from the loaded organic. The pilot scale study (0.2 m3/day) and plant operation (30 m3/day) were able to be continuously operated to recover 99% Mo from the wash liquor, from which high purity MoO3 and CaMoO4 of >99.9% purity could be recovered. 相似文献
944.
掺杂Y_2O_3,Sm_2O_3对氧化铝瓷介电性能的影响 总被引:1,自引:0,他引:1
研究了Y2O3、Sm2O3对氧化铝瓷烧结性能、介电性能和显微组织的影响。研究结果表明,Y2O3、Sm2O3在氧化铝瓷的烧结过程中可以显著降低氧化铝瓷的烧成温度,抑制晶粒生长,使晶粒尺寸变小,提高了陶瓷的致密性,降低了试样的结构损耗。掺稀土氧化物的氧化铝瓷在1600℃保温2h烧结后,相对密度达98.8%以上,介质损耗达到4.2×10-3。 相似文献
945.
The EVA-150 and starch were extruded by extruding press and the bio-degradation composite material was prepared to use as
the controlled-release matrix of imazethapyr. The compatibility and crystallinity of EVA-150/starch blending were analyzed
by SEM and DSC, and the controlled-released performance of imazethapyr in the carriers was also investigated by UV analysis.
The results show that EVA-150/starch composite matrix has the obvious controlled-released function and the release rates of
imazethapyr all exceed 50% in the environment of pH4, pH7, or pH9 after nine days.
Supported by the Enterprise Postdoctoral Fund of Liaoning Province(BSH2005921077) 相似文献
946.
947.
Sujuan Wu Hongwei HanQidong Tai Jing ZhangSheng Xu Conghua ZhouYing Yang Hao HuBoLei Chen Xing-zhong Zhao 《Journal of power sources》2008
A novel surface modification method was carried out by reactive dc magnetron sputtering to fabricate TiO2 electrodes coated with Al2O3 for improving the performance of dye-sensitized solar cells (DSSCs). The Al2O3-coated TiO2 electrodes had been characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV–vis spectrophotometer, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The study results revealed that the modification to TiO2 increases dye absorption amount, reduces trap sites on TiO2, and suppresses interfacial recombination. The impact of sputtering time on photoelectric performance of DSSCs was investigated. Sputtering Al2O3 for 4 min on 5-μm thick TiO2 greatly improves all cell parameters, resulting in enhancing the conversion efficiency from 3.93% to 5.91%. Further increasing sputtering time decreases conversion efficiency. 相似文献
948.
This paper presents an overview of instrumentation and control (I&C) systems of a pressurized water reactor (PWR) type nuclear power plant (NPP) in Korea. Yonggwang unit 3, which was constructed as a basis model for a Korea standard nuclear power plant (KSNP), is selected as an example for the presentation. This overview is derived from analyzing the I&C systems based on a top-down approach. The I&C systems consist of 30 systems. The 183 I&C cabinets are also analyzed and mapped to the systems. The overview is focused on an interface between the systems and the cabinets. This information will be used to understand the implementation of the I&C systems and to group the systems for an upgrade. 相似文献
949.
Nick E. Tran Samuel G. Lambrakos Joseph J. Lagowski 《Journal of Materials Engineering and Performance》2009,18(1):95-101
Fullerenes and their derivatives are promising materials for supercapacitor devices due to their unique nanostructure that
combines the reversible redox charge storage with the high surface area. In this article, the reversible redox charge storage
of C60, C70, and La@C82 in liquid ammonia solution is reported. An electrochemical analysis of these species using cyclic voltammetry is presented
in conjunction with the theoretical interpretation. The relative magnitudes of transfer coefficients, which represent a measure
of the symmetry of the energy barrier for oxidation and reduction of the monoanionic species of these fullerenes, suggest
that the availability of the surface area permitting delocalization of π electrons is a determining factor of their first
reduction potential. The relationship between these transfer coefficients and fullerene geometry also support previous conclusions
that the La atom is located within the fullerene cage of La@C82. The electrochemical measurements analyzed were made using a modified three-compartment cell. Advantages associated with
this modified cell for analysis of capacitance characteristics of C60, C70, and La@C82 are discussed. 相似文献
950.
以氮化铝、金属Mo 为原料,Y2O3为烧结助剂,氮气氛下、1800~1900℃热压烧结制备Mo/AlN 复相材料。利用 XRD、SEM对材料的相组成、显微结构进行表征,四探针法测试复相材料的电阻率,微带线法测试2~20 GHz频率范围内材料的微波衰减特性,探讨了渗流现象与衰减特性之间的内在联系。结果表明;当 Mo 添加量为4. 56 vol %~15. 03 vol %,材料呈现宽频衰减特性,且随着 Mo 含量和烧结温度的增加衰减量增大;当Mo 添加量为16. 18 vol %~24. 88 vol %,材料仅在 6、10、14、18 GHz? 4个频率点出现了明显的谐振峰。根据渗流模型对电阻率数据进行拟合,得到导电相渗流阈值Vc和相应电阻率分别为14. 87 vol %和11. 59 Ω·m。当Mo 体积分数V >Vc时 , 复相材料的衰减特性由宽频向选频转变。 相似文献