This paper proposed an advanced technology, which based on DSP and FPGA, applied in the fully digital and high-performance permanent magnet synchronous motor (PMSM) AC servo system. In the system, DSP unit implemented...
详细信息
This paper proposed an advanced technology, which based on DSP and FPGA, applied in the fully digital and high-performance permanent magnet synchronous motor (PMSM) AC servo system. In the system, DSP unit implemented the position loop control by combining PI control and feedforward control, while FPGA unit implemented the speed loop and current loop control. Since FPGA provided a kind of hardware design scheme for the control system, it had the features of a special control IC. The functions of vector control algorithm, velocity and current sampling, space vector pulse width modulation and PI algorithm were included in the special control IC. In the meanwhile, it also provided host communication interfaces that could realize the real-time modification of the control parameters in the IC. Finally, the experimental results indicate that this system has highspeed response and well static state control performance
The Emeishan large igneous province in the western Yangtze Block was resulted from a mantle plume at end of the Middle Permian. Four super-large V-Ti-magnetite deposits and 10 large-medium Ni-Cu-(PGE) sulfide deposits...
详细信息
The Emeishan large igneous province in the western Yangtze Block was resulted from a mantle plume at end of the Middle Permian. Four super-large V-Ti-magnetite deposits and 10 large-medium Ni-Cu-(PGE) sulfide deposits have been explored in the Emeishan large igneous province. Precise age data indicated that these ore-bearing mafic-ultramafic intrusions were produced by the same mantle plume that caused the Emeishan flood basalts at 260 Ma±. The maficultramafic intrusion hosting V-Ti-magnetite deposits and Ni-Cu-(PGE) sulfide deposits are distinguished in localization, scale, rock-assemblages, components of rock-forming minerals. The Emeishan large province can be divided to Inner- and Outer-Zones. The Inner-Zone is marked by large thickness of the Emeishan flood basalts, large layered intrusions, mafic-ultrmafic intrusive bodies, low-Ti basalts, alkaline intrusions, and various mineralizations related to the mantle plume. The basalts become thinner and consist of high-Ti basalts in the Outer-Zone where fewer mafic-ultramafic bodies are exposed. Special and geochemical relationship between the two type of magmatic deposits and high- and low-Ti basalts,the study on petrogenetic links between the Ni-Cu-(PGE) sulfide deposits and the Emeishan flood basalts in the Yangliuping area indicate that the magmatic deposits formed in different dynamic stages of the mantle plume. The V-Ti-magnetite deposits are associated with the high-Ti basaltic magmas and related to fractional crystallization. In contrast, the Ni-Cu-(PGE) sulfide mineralization may be related to either the high- or low-Ti basaltic magmas and controlled by three factors: high degree partial melting of upper mantle, contamination of the lower crust, and fractional crystallization. The Ni-Cu-(PGE) sulfide deposits were formed earlier than the V-Ti-magnetite deposits.
This paper derives a closed-form expression for the Cramér-Rao bound (CRB) on estimating the source signals in the linear independent component analysis problem, assuming that all independent components have fini...
详细信息
This paper derives a closed-form expression for the Cramer-Rao bound (CRB) on estimating the source signals in the linear independent component analysis problem, assuming that all independent components have finite va...
详细信息
This paper derives a closed-form expression for the Cramer-Rao bound (CRB) on estimating the source signals in the linear independent component analysis problem, assuming that all independent components have finite variance. It is also shown that the fixed-point algorithm known as FastICA can approach the CRB (the estimate can be nearly efficient) in two situations: (1) when the distribution of the sources is not too much different from Gaussian, for the symmetric version of the algorithm using any of the custom nonlinear functions (pow3, tanh, gauss); (2) when the distribution of the sources is very different from Gaussian (e.g. has long tails) and the nonlinear function in the algorithm equals the score function of each independent component.
The fixed point algorithm, known as FastICA, is one of the most successful algorithms for independent component analysis in terms of accuracy and low computational complexity. This paper derives analytic closed form e...
详细信息
The fixed point algorithm, known as FastICA, is one of the most successful algorithms for independent component analysis in terms of accuracy and low computational complexity. This paper derives analytic closed form expressions that characterize separating ability of both one-unit and symmetric version of the algorithm in a local sense. Based on the analysis it is possible to combine advantages of the two versions. Although the analysis assumes a "good" initialization of the algorithms and long data records, our computer simulations demonstrate validity of the theoretical expressions in the case of arbitrary initialization and moderate data lengths
Self-assembled monolayers (SAMs) on coinage metal provide versatile modeling systems for studies of interfacial electron transfer, biological interactions, molecular recognition and other interfacial phenomena. Recent...
详细信息
Self-assembled monolayers (SAMs) on coinage metal provide versatile modeling systems for studies of interfacial electron transfer, biological interactions, molecular recognition and other interfacial phenomena. Recently the bonding of enzyme to SAMs of alkanethiols onto Au electrode surfaces was exploited to produce a bio-sensing system. In this work, the attachment of trypsin to a SAMs surface of 11-mercaptoundecanoic acid was achieved using water soluble N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide as coupling agent. Experimental results have revealed that the XPS C1s core levels at 286.3 and 286.5 eV (C with N), 288.1 eV (Amide bond) and 289.3 eV (Carboxylic acid) illustrate the immobilization of trypsin. These data are also in good agreement with FTIR-ATR spectra for the peaks valued at 1659.4 cm-1 (Amide I) and 1546.6 cm-1 (Amide II). Using nano-HPLC-ESI-MS/MS observations, analytical results have demonstrated the human plasma proteins digestion of the immobilized trypsin on the functionalized SAMs surface. For such surfaces, human plasma proteins were digested, which shows the enzyme digestion ability of the immobilized trypsin. The terminal groups of the SAMs structure can be further functionalized with biomolecules or antibodies to develop surface-base diagnostics, biosensors, or biomaterials.
暂无评论