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71.
H.A. Barker Author Vitae A.H. Tan Author Vitae K.R. Godfrey Author Vitae 《Automatica》2003,39(1):127-133
Analysis of systems with direction-dependent dynamics is currently limited to cases in which the dynamics in the two directions of the output are first order; results for such systems have been published for both pseudo-random maximum-length binary (MLB) and inverse-repeat maximum-length binary (IR-MLB) inputs. These relatively limited analytical results make it useful to examine alternative ways of modelling such systems and in this paper, Wiener models are considered for this purpose. Methods for optimising the Wiener model parameters by matching the system and model cross-correlation functions, outputs, and discrete Fourier transforms of the outputs are considered, and the results are compared. These methods are also applied to a first-order direction-dependent system with a maximum-length ternary (MLT) input, for which no analytical results are currently available, and to a second-order system with an IR-MLB input. 相似文献
72.
谈金祝 《石油化工设备技术》1998,19(6):54-56
采用恒位移试验方法,在高温、高压、氢环境中用WOL试样测试了214Cr-1Mo钢及其焊接接头的应力腐蚀门限应力强度因子KIH。试验结果表明:采用恒位移试验方法测试高温、高压、氢环境中214Cr-1Mo钢及其焊接接头的KIH是可行的。 相似文献
73.
Films of electroactive polymers, such as polyaniline (PAN) in its emeraldine base form, and poly(3-alkylthiophene), poly(3-hexylthiophene) (P6TH), poly(3-octylthiophene) (P8TH), and poly(3-dodecylthiophene) (P12TH) can be readily functionalized via thermal or near ultraviolet-light-induced surface graft copolymerization with monomers of polyelectrolyte, polyampholyte and polymeric acids. The monomers used in the present work include dimethyl sulphate quaternized dimethylamino-ethylmethacrylate (DMAEM·C2H6SO4), 3-dimethyl(methacryloyloxyethyl)ammonium propane sulphonate (DMAPS), acrylic acid (AAc) and a sodium salt of styrene sulphonic acid (NaSS). The surface structures and compositions of the electroactive polymer films after functionalization via graft copolymerization were characterized by angle-resolved X-ray photoelectron spectroscopy. Graft copolymerization of poly(3-alkylthiophene) films, but not PAN films, with the hydrophilic monomers readily results in a stratified surface microstructure arising from the migration of the hydrophilic graft chains beneath a thin surface layer which is much richer in the substrate chains. On the other hand, graft copolymerization of PAN films with AAc and NaSS readily gives rise to a self-protonated (and thus conductive) surface structure. 相似文献
74.
本文用逐步选择因素组合法,对锥形件拉深临界压边力试验数据进行了处理,所得数学模型比一般逐步回归法具有更高的精度和可靠性,模型更为完善。 相似文献
75.
用流动微量量热法研究了十二烷基硫酸钠(SDDS)和十二碳羧酸钠(SL)在克拉玛依油田九区和乌尔禾区油砂上的吸附,简要地计论了吸附机理。所得实验结果表明,SL 在油砂上的吸附强度比 SDDS 的要大,在相当低的浓度下即可迟到饱和吸附。 相似文献
76.
Dynamic oxide voltage relaxation spectroscopy 总被引:3,自引:0,他引:3
Mingzhen Xu Changhua Tan Yandong He Xiaowei Liu Yangyuan Wang 《Electron Devices, IEEE Transactions on》1996,43(4):628-635
A new method for trap characterization of oxidized silicon is described. The Dynamic Oxide Voltage Relaxation Spectroscopy (DOVRS) is an improved version of the formerly proposed Oxide Voltage Relaxation Spectroscopy (OVRS) technique which applies a periodic long duration constant current for tunneling injection. It has been demonstrated that the new technique can be used not only to separate and identify the oxide trap from interface trap, but also to separate and determine the centroid from the oxide trap density generated in the MOS system by the tunneling current stress. In the pulse constant current mode, the OVRS measurement can be completed instead of using the double current-voltage technique. Thus the new method results in more accurate and quicker measurements of the oxide trap centroid. Analytical expressions for computing the paramaters of the interface and oxide traps are derived. The effect of the channel carrier mobility on the spectroscopy is also considered. Two types of oxide and two types of interface traps were observed at a pulse constant Fowler-Nordheim current stress by the new method of DOVRS 相似文献
77.
This paper describes the application of an expert system for the evaluation of the short-term thermal rating and temperature rise of overhead conductors. The expert system has been developed using a database and Leonardo expert system shell which is gaining popularity among commercial tools for developing expert system applications. The expert system has been found to compare well when evaluated against site tests. A practical application is given to demonstrate the usefulness of the expert system developed 相似文献
78.
Although the good appearance and biocompatibility of dental porcelains, failures are still of considerable concern because of the limited properties to all ceramic system. Physical properties that might be considered ideal include high strength, resistance to abrasion, and resistance to the hostile oral environment. Porcelain has been considered by many of its physical characteristic are similar to those of enamel. In 1983 a new modality of treatment, the etched porcelain restoration was introduced by Simonsen and Calamia. Numerous investigations have shown the strength of the etched porcelain bonded to composite resin and also the clinical success of this porcelain to be used as laminated veneers and etched inlays and onlays. 相似文献
79.
80.
Tan Fu Lei Tang Po Chen Horng-Chih Lin Chun-Yen Chang 《Electron Devices, IEEE Transactions on》1995,42(12):2104-2110
A new material, Si-B, is proposed as a solid diffusion source for fabrication of poly-Si contacted p+-n shallow junctions. The junction depth of the Si-B source diode has been measured and compared with that of a BF2+-implanted poly-Si source diode. It was found that the Si-B source diode had a much shallower junction and was less sensitive to thermal budget than the BF2+ source diode. This was attributed to the smaller surface concentration and diffusivity of boron in the silicon in Si-B source diodes. Regarding electrical characteristics of diodes with a junction depth over 500 Å, a forward ideality factor of better than 1.01 over 8 decades and a reverse-current density lower than 0.5 nA/cm2 at -5 V were obtained. As the junction depth shrank to 300 Å, the ideality factor and reverse current density of diodes increased slightly to 1.05 and 1.16 nA/cm2, respectively. These results demonstrated that a uniform ultrashallow p+-n junction can be obtained by using a thin Si-B layer as a diffusion source 相似文献