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51.
随着三网融合的大力推进以及双向互动业务的大力开展,运营商使用原有简单的EPG不足以支撑开展更多的增值业务,不能主动为用户推荐节目,不能为运营商带来新的收入机会。作为重要的创新能力支撑系统,介绍了江苏有线智能导航平台的设计与应用,为相关广电运营商提供一定的设计参考。 相似文献
52.
53.
Xueli Chen Ke Liu Qianwan Qin Zhenlu Yu Meiqing Li Xingyu Qu Yu Zhou Aichun Dou Mingru Su Yunjian Liu 《Ceramics International》2021,47(11):15400-15407
With excellent specific capacity, superior cycle stability, safety and strong practical, Nb2O5 has been considered as one of the prospective anode materials for lithium-ion batteries (LIBs). However, current study suggests that Nb2O5 electrode materials for LIBs still face the vital issues of low electrical conductivity and poor rate performance. Therefore, carbon-coated TT-Nb2O5 materials are designed and synthesized through solid state method in this work, which present high specific capacity (228 mA h g?1 at 0.2C), satisfactory rate properties (107 mA h g?1 at 20 C). The outstanding electrochemical property can not only give the credit to the pseudocapacitance effect of TT-Nb2O5, but also attribute to introduction of carbon. The homogeneous carbon-coated materials enhance the electrical conductivity, increase the electron transmission speed and alleviate particle crushing. This research not only offers a new method for preparing excellent electrode materials, but also provides a kind of excellent anode material with prospective application for LIBs. 相似文献
54.
《Ceramics International》2022,48(10):14349-14359
The influence of heat-treatment temperatures (700 °C, 900°C, 1200 °C) on the phase, physical properties, crystallization rate, and in vitro properties of the solution combustion synthesized silicon-doped calcium phosphates (CaPs) were investigated. The thermodynamic aspects (enthalpy, entropy, and free energy) of the synthesis process and the crystallographic properties of the final samples were first predicted and then confirmed using density functional theory (DFT). Results demonstrated that the crystallization rate was controlled by the fuel(s) type (glycine, citric acid, and urea) and the amounts of Si4+ ions (0, 0.1, 0.4 mol). The highest calculated crystallization rate values of the un-doped, 0.1, and 0.4 mol Si-doped samples were 64%, 22%, 38%, respectively. The obtained results from the DFT simulation revealed that crystal growth in the direction of c-axis of hydroxyapatite (HAp) structure could change the stability of (001) surface of (HAp). Also, the computational data confirmed the adsorption of Si–OH groups on the (001) surface of HAp during the SCS process with an adsorption energy of 1.53 eV. AFM results in line with DFT simulation showed that the observed change in the surface roughness of Si-doped CaPs from 2 to 8 nm could be related to the doping of Si4+ ions onto the surface of CaPs. Besides, the theoretical and experimental investigation showed that crystal growth and doping of Si4+ ions could decrease the activation energy of oxygen reduction reaction (ORR). Furthermore, the results showed that the crystallized HAp structure could have great potential to efficiently reduce oxidative stress in human body. 相似文献
55.
《Ceramics International》2022,48(1):811-823
Polyaniline (PANI)-based networks combined with Fe3O4 hollow spheres and carbon balls (FCP) for improved electromagnetic wave (EMW) absorption were investigated using an easy-to-industrialize solvothermal and physical method. Hollow structure Fe3O4 spheres with a lower density than that of the common solid sphere were prepared. As a thin and light magnetic material, Fe3O4 hollow spheres generate magnetic loss, carbon balls and PANI networks generate dielectric loss. The magnetic and conductive parts play appropriate roles in achieving complementarity in the EMW absorption. The relatively high specific surface area introduced by PANI networks promotes interfacial polarization and further supports dielectric loss. In conclusion, the above reasons provide multiple attenuation mechanisms. Samples FCP1 (?65.109 dB, at 12.800 GHz, 1.966 mm, from 5.6 to 18.0 GHz) and FCP2 (?61.033 dB, at 8.480 GHz, 3.328 mm, from 4.3 to 18.0 GHz) demonstrated a wide bandwidth, a small thickness, a minimum reflection loss (RL), and a low loading ratio (25%) in paraffin-based composites. Specifically, their loading ration of 25% is much lower than the loading ratio of conventional materials (usually 50% and above). In addition, the bandwidth is excessively wide, above 12 GHz, possessing good absorption performance in continuous intervals with different thicknesses. Such excellent characteristics have rarely been reported in literature. 相似文献
56.
瞬态剂量率辐射试验会引起集成电路发生损伤或失效,其原因至少有两种:闭锁大电流引起的电路内部金属互连熔融;累积电离总剂量引起的氧化层电荷造成阈值电压偏移。本文以一种0.13 μm体硅CMOS处理器为对象,研究了瞬态剂量率和稳态电离总剂量辐射效应规律。结果表明:瞬态剂量率闭锁效应对处理器造成了显著的潜在损伤,导致其总剂量失效阈值从1 030 Gy(Si)降低至600 Gy(Si)。研究结论对于大规模集成电路的可靠性评估和指导辐射加固设计有重要参考意义。 相似文献
57.
The importance of cultural heritage for supporting the knowledge economy has promoted its digitisation and online publication. Many cultural heritage repositories have published millions of digitised items using semantic web technologies and Linked Data approaches. These repositories frequently use knowledge organisation systems to classify the resources, but the domain heterogeneity makes it difficult to know if they are the most suitable ones. This paper describes the process used to discover and profile the knowledge organisation systems used in the cultural heritage domain. Additionally, for those knowledge organisation systems with a thesaurus-like structure, a detailed quality analysis is performed. The results of this analysis can be used as a key factor for the selection of knowledge organisation systems in classification tasks. 相似文献
58.
叶婉玲 《电信工程技术与标准化》2019,32(8)
从MR原始数据特性出发研究数据结构与字段,采用基于线状特性分析MR大数据的地铁用户识别过滤方法和位置定位方法,该方法经过验证能够有效输出地铁用户数据并定位在地图上,解决人工地铁测试效率低且测试片面的问题,实现基于大数据的自动化地铁网络评估,提供海量的有效定位数据用于地铁评估与分析。 相似文献
59.
连续油管钻井机器人利用机身内外的钻井液压力差作为动力源,可在牵引连续油管的同时加载钻压。以钻井机器人为基础,建立连续油管钻柱动力学模型,并推导出通过钻井液排量控制钻压和钻速的单参数控制数学模型;对钻井机器人引入调速回路,建立具有调速功能的钻柱动力学模型;在溢流阀调定压力大于机身内外压差时,推导出利用钻井液排量和节流阀流通面积两种参数控制钻压、钻速的数学模型,在溢流阀调定压力小于机身内外压差时,推导出利用钻井液排量、节流阀流通面积和溢流阀调定压力3种参数控制钻压、钻速的数学模型;以11.43 cm(4.5英寸)井眼为例,对上述3种数学模型进行了分析。分析结果表明:钻压、钻速随钻井液排量的增加基本呈线性增加,在钻井液排量大于0.005 m3/s时,钻井机器人能够向前爬行,在钻井液排量大于0.005 7 m3/s时,钻头能够正常钻进;调节节流阀流通面积和溢流阀调定压力,可以在一定范围内无级调钻压和钻速;3种控制方法相结合,可以实现小排量、大钻压,及大排量、小钻压等钻井参数的控制。以控制模型为基础,针对不同井下工况建立钻进工艺的专家数据库,以钻井机器人为"大脑",结合井下随钻测量数据就能够实现闭环控制,自动钻进。 相似文献
60.
For rechargeable wireless sensor networks, limited energy storage capacity, dynamic energy supply, low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanently from a source to destination in a distributed scenario. Therefore, before data delivery, a sensor has to update its waking schedule continuously and share them to its neighbors, which lead to high energy expenditure for reestablishing path links frequently and low efficiency of energy utilization for collecting packets. In this work, we propose the maximum data generation rate routing protocol based on data flow controlling technology. For a sensor, it does not share its waking schedule to its neighbors and cache any waking schedules of other sensors. Hence, the energy consumption for time synchronization, location information and waking schedule shared will be reduced significantly. The saving energy can be used for improving data collection rate. Simulation shows our scheme is efficient to improve packets generation rate in rechargeable wireless sensor networks. 相似文献