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91.
With user-generated content, anyone can De a content creator. This phenomenon has infinitely increased the amount of information circulated online, and it is beeoming harder to efficiently obtain required information. In this paper, we describe how natural language processing and text mining can be parallelized using Hadoop and Message Passing Interface. We propose a parallel web text mining platform that processes massive amounts data quickly and efficiently. Our web knowledge service platform is designed to collect information about the IT and telecommunications industries from the web and process this in-formation using natural language processing and data-mining techniques.  相似文献   
92.
Molecular dynamics simulation has been carried out to study the mechanical properties of Mg2Si nanofilm. For the binary thermoelectric material Mg2Si with antifluorite crystal structure, a modified Morse potential energy function in which the bond-angle deformation has been taken into account is developed and employed to describe the atomic interactions to shed light on its mechanical properties. In the simulation, the radial distribution function of Mg2Si nanofilm is computed to validate its crystal structure, and the stress–strain responses of the nanofilm are examined at room temperature. It is found that the mechanical properties of Mg2Si nanofilm are quite different from those of bulk Mg2Si due to the impact of surface atoms of the nanostructures. The size effect and the temperature effect on the mechanical properties of Mg2Si nanofilm are discussed in detail.  相似文献   
93.
佛山供电局海量实时数据采用PI数据库进行存储,目前已经有270多万PI点,是全球首家超过200万点的厂家。目前对PI点的管理缺乏确实有效的方法,本文提出了一种基于业务模型的PI点自动维护方法,从模型同步、PI点创建、完整性检测、PI点清理四个方面实现PI点的自动维护,有效的保证了PI点的准确性、实时性和同业务模型的一致性。  相似文献   
94.
A sintering-aid system using melting of B-Li glass for barium strontium titanate (BST)-based compositions to be used in low-temperature cofired ceramic (LTCC) layers is introduced. The effects of the sintering aid on the microstructure, dielectric properties, and application in LTCC were investigated. The composition Ba0.5Sr0.5TiO3-SrMoO4 with 3 wt.% B-Li glass sintered at 950°C exhibits optimized dielectric properties, including low dielectric constant (368), low dielectric loss (0.007), and moderate tunability (13%, 60 kV/cm) at 10 kHz. At 1.44 GHz, it possesses a dielectric constant of 218 and Q value of 230. LTCC multilayer ceramic capacitors fabricated by the tape-casting process have steady relative tunability of 12% at 300 V, suggesting that BST50-SrMoO4-B-Li glass composite ceramic is a promising candidate for electrically tunable LTCC microwave device applications.  相似文献   
95.
Controllable surface adhesion of solid substrates has aroused great interest both in air and underwater in solving many challenging interfacial science problems such as robust antifouling, oil‐repellent, and highly efficient oil/water separation materials. Recently, responsive surface adhesion, especially switchable adhesion, under external stimulus in air has been paid more and more attention in fundamental research and industrial applications. However, phototunable underwater oil adhesion is still a challenge. Here, an approach to realize phototunable underwater oil adhesion on aligned ZnO nanorod array‐coated films is reported, via a special switchable contact mode between an unstable liquid/gas/solid tri‐phase contact mode and stable liquid/liquid/solid tri‐phase contact mode. The photo‐induced wettability transition to water and air exists (or does not) in the micro/nanoscale hierarchical structure of the mesh films, playing important role in controlling the underwater oil adhesion behavior. This work is promising in the design of novel interfacial materials and functional devices for practical applications such as photo‐induced underwater oil manipulation and release, with loss‐free oil droplet transportation.  相似文献   
96.
新型显示技术是数字化时代的一大重点发展技术.阐述新型显示技术产业发展现状,重点介绍有源矩阵有机发光二极管(Active Matrix Organic Light Emitting Diode,AMOLED)、微型发光二极管(Micro-Light Emitting Diode,Micro LED)、激光显示以及电子纸4...  相似文献   
97.
以KBH4和维生素C(VC)为还原剂,以CuSO4·5H2O为原料,以EDTA为络合剂,PVP为分散剂,用液相还原法制备不同晶粒度的纳米铜粉。不同晶粒度的纳米铜粉同时在空气中放置1h后,进行XRD、DTA-TG以及TEM检测。结果表明:不同粒度的纳米铜粉在空气中抗氧化能力不同,晶粒度越大抗氧化能力越强。晶粒度大于75nm时在空气中放置1h不被氧化,平均晶粒度为75nm的纳米铜粉在120℃时开始氧化。纳米铜粉的熔点很低,进行TEM检测时,在电子束照射下颗粒熔融长大。  相似文献   
98.
The adaptive neuro-fuzzy inference system (ANFIS) has been widely used for modeling different kinds of nonlinear systems including RF power amplifiers (PAs). The modified ANFIS (MANFIS) architecture is simpler than that of ANFIS, but with nearly the same performance for modeling nonlinear systems. In this paper, the MANFIS is applied to model RF PAs with memory effects. The simulation and experimental results both in the time and frequency domains show that this model has good modeling accuracy and the characteristics of faster convergence and lower computational complexity compared with the ANFIS model. The normalized mean squared errors of the MANFIS model are slightly lower than those of some other neural network models such as the real-valued time delay neural network, radial basis-function neural network, etc. Finally, the MANFIS model is successfully used in a digital predistortion system, which can provide over 10- dB adjacent channel leakage ratio improvement for three-carrier wideband code division multiple access signals.  相似文献   
99.
Multielemental systems enable the use of multiple degrees of freedom for control of physical properties by means of stoichiometric variation. This has attracted extremely high interest in the field of 2D optoelectronics in recent years. Here, for the first time, multilayer 2D ternary Ta2NiSe5 flakes are successfully fabricated using a mechanical exfoliation method from chemical vapor transport synthesized high quality bulk and the optoelectronic properties are systematically investigated. Importantly, a high responsivity of 17.21 A W?1 and high external quantum efficiency of 2645% are recorded from an as‐fabricated photodetector at room temperature in air; this is superior to most other 2D materials‐based photodetectors that have been reported. More intriguingly, a usual sublinear and an unusual superlinear light‐intensity‐dependent photocurrent are observed under air and vacuum, respectively. These excellent and special properties make multilayer ternary Ta2NiSe5 a highly competitive candidate for future infrared optoelectronic applications and an interesting platform for photophysics studies.  相似文献   
100.
Design of a Concentration Solar Thermoelectric Generator   总被引:1,自引:0,他引:1  
Thermoelectric technology can be another direct way to convert solar radiation into electricity, using the Seebeck effect. Herein, a prototype concentration solar thermoelectric generator (CTG) and a discrete numerical model for the evaluation of the whole system are presented. The model takes into account the temperature dependence of the thermoelectric material properties by dividing the thermoelectric leg into finite elements and is proved to be more accurate for calculation of the conversion efficiency of the thermoelectric modules when large temperature gradients occur in the CTG system. Based on the best available properties of various bulk thermoelectric materials reported in the literature, the best possible performance of the CTG system is predicted, and the CTG system design, including the selection of the concentration ratio and the cooling method for different thermoelectric materials, are discussed in detail.  相似文献   
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