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基于同步变距的输变电线路在线监测WSN路由协议研究 被引量:3
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作者 郭稳涛 程沅 +2 位作者 郑剑 李兵 何怡刚 《四川大学学报(自然科学版)》 CAS CSCD 北大核心 2018年第5期1000-1006,共7页
基于先进传感、信息通信的输变电设备运行状态在线监测技术已成为电力系统的发展趋势.输电线路状态在线监测网络具有链状、数据传输量大和传输距离长等特点,能量热区问题显著.为均衡输电线路在线监测中无线传感器网络的能量消耗,提出了... 基于先进传感、信息通信的输变电设备运行状态在线监测技术已成为电力系统的发展趋势.输电线路状态在线监测网络具有链状、数据传输量大和传输距离长等特点,能量热区问题显著.为均衡输电线路在线监测中无线传感器网络的能量消耗,提出了一种基于同步变距的全局能量均衡路由算法EBRA-SVD.采取多个子网络方式,缩短数据传输距离,从而缓解长距多径损耗而产生的"能量热区"问题.仿真显示,EBRA-SVD可有效均衡网络能耗,提升网络寿命. 展开更多
关键词 无线传感器网络 能量优化路由协议 链状拓扑 能量热区
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适用于低数据聚合率网络的能耗均衡路由算法 被引量:2
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作者 程沅 李兵 +2 位作者 何怡刚 佐磊 尹柏强 《电子测量与仪器学报》 CSCD 北大核心 2016年第10期1591-1598,共8页
有效的分簇算法是实现无线传感网络能耗均衡,延长网络生存周期的关键。针对概率分簇算法随机选择簇首(CH)引起的低残余能量节点被选为簇首及迭代次数高的问题,提出一种新的半集中式分簇方法,候选簇首由前簇首推荐并通过候选簇首间竞争... 有效的分簇算法是实现无线传感网络能耗均衡,延长网络生存周期的关键。针对概率分簇算法随机选择簇首(CH)引起的低残余能量节点被选为簇首及迭代次数高的问题,提出一种新的半集中式分簇方法,候选簇首由前簇首推荐并通过候选簇首间竞争决定最终簇首;针对重负荷网络中的能量热区问题,引入非均匀分簇和单跳、多跳混合传输机制,提出一种适用于低数据聚合率网络的半集中式非均匀分簇(SCUC)的能耗均衡路由算法。仿真实验结果表明,SCUC算法第一个节点死亡时间较HEED算法延长111.24%,较EEUC延长74.62%。所提算法有效均衡网络能耗,延长生存周期。 展开更多
关键词 能量热区 单跳 多跳混合传输机制 半集中式 半集中式非均匀分簇
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Antioxidant Capacity and Total Phenol Content of Commonly Consumed Indigenous Foods of Asian Tropical Regions 被引量:1
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作者 Nazuma Shaheen Masao Goto +1 位作者 Jun Watanabe Yuko Takano-Ishikawa 《Journal of Food Science and Engineering》 2012年第4期187-195,共9页
In order to screen the antioxidant capacity of commonly consumed indigenous foods of tropical region, vegetables, fruits, tea, oil seeds, legumes, spices and cereal were analyzed. Among the vegetables, green chili sho... In order to screen the antioxidant capacity of commonly consumed indigenous foods of tropical region, vegetables, fruits, tea, oil seeds, legumes, spices and cereal were analyzed. Among the vegetables, green chili showed the highest total oxygen radical absorbance capacity (ORACFL) and lipophilic ORAC (L-ORACFL); whereas, bean showed highest hydrophilic ORAC (H-ORACFL) content. The H-ORACFL of vegetable samples varied between 2.26 to 23.08 ~tmol of Trolox equivalent (TE)/g of fresh weight (FW) and L-ORACFL content widely varied from 0.20 (sweet pumpkin) to 16.95 (green chili). The range of H-ORACFL values of fruits showed large variation (0.45-178 Ixmol of TE/g FW). All four different types of tea showed high H-ORACFL (1,295.84-2,709.11 lamol of TE/g), in contrast to negligible amount of L-ORACFL. In legumes, H-ORACFL content ranged from 16.22 to 140.54; whereas, L-ORACFL ranged from 4.43 to 25.78. Porso millets showed higher L-ORACFL value (19.4) as compared to H-ORACFL (0.8). In case of spices, L-ORACFL content varied from 29.75 ± 0.00 to 1,575.24 ± 39.63, which is considerably higher as compared to H-ORACFL (61.68 ± 1.71 to 272.82± 1.05) content. Comparatively, spices showed much higher H-ORACFL values as compared to fruits analyzed. In case of selective vegetables, fruits and tea samples, the total phenol content was highly correlated with the H-ORACFL content. 展开更多
关键词 Hydrophilic and lipophilic antioxidant capacity POLYPHENOL indigenous foods Bangladesh.
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Environmental Low Energy Gamma Rays Measurements in Brazilian Tropics Region During 2016
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作者 Inaicio Malmonge Martin Anatoli Alexandrovitch Goussev +5 位作者 Douglas Carlos Vilela Marcelo Pego Gomes Mauro Angelo Alves Alessandro de Abreu Matheus Carlos Silva Rodrigo Rezende Femandez de Carvalho 《Journal of Environmental Science and Engineering(A)》 2016年第11期559-565,共7页
Low energy gamma radiation (0.2-10.0) MeV near the Earth's surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons (〉 1 GeV) in terrestrial atmosphere a... Low energy gamma radiation (0.2-10.0) MeV near the Earth's surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons (〉 1 GeV) in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas (Rn-222) that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges (lightning strikes) and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA (Technological Institute of Aeronautics) campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena. 展开更多
关键词 Gamma radiation atmospheric phenomena electric discharges radon gas.
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De Haas-van Alphen Effect of Free Electron Gas Revisited
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作者 林琼桂 何思源 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第1期87-96,共10页
The free electron gas in a uniform magnetic field at low temperature is restudied. The grand partition function previously obtained by Landau's quantitative calculation contains three parts, which are all approximate... The free electron gas in a uniform magnetic field at low temperature is restudied. The grand partition function previously obtained by Landau's quantitative calculation contains three parts, which are all approximate. An improved calculation is presented, in which two of the three parts are obtained in exact forms. A simple remedy for Landau and Lifshitz's qualitative calculation in the textbook is also given, which turns the qualitative result into the same one as obtained by the improved quantitative calculation. The chemical potential is solved approximately and the thermodynamic quantities are caiculated explicitly in both a weak field and a strong field. The thermodynamic quantities in a strong field obtained here contain both non-oscillating and oscillating corrections to the corresponding results derived from Landau's grand partition function. In particular, Landau's grand partition function is not sufficiently accurate to yield our nonzero results for the specific heat and the entropy. An error in the Laplace-transform method for the problem is corrected. The results previously obtained by this method are also improved. 展开更多
关键词 free electron gas magnetic field de Haas-van Alphen effect
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