The transverse flux permanent magnet synchronous machine (TFPM) is a novel machine arousing widespread concern in recent years. Achieving high torque density to save energy and rough material and reduce the volume and...
详细信息
ISBN:
(纸本)9787506292214
The transverse flux permanent magnet synchronous machine (TFPM) is a novel machine arousing widespread concern in recent years. Achieving high torque density to save energy and rough material and reduce the volume and weight of the machine is the best features of TFPM. However, because of low power factor and complex manufacture technics, the application of TFPM is restricted. The dissertation is devoted to the study on TFPM in this paper. Power factor of TFPM is discussed in theory. The orientation to obtain high power factor is given. By comparing impact of different structure patterns on leakage flux, axial magnet is proved to be better to restrain leakage flux and enhance main flux. Impact of parameter variety on torque density is analyzed by comparing radial flux machine with transverse flux machine. A 5kW TFPM prototype is developed. Power factor of prototype is 0.8. Torque density of prototype is about twice of common radial machine.
This article proposes a new method for a determination of the two-dimensional distribution in systems with overflow traffic. The method proposed in the article offers a significant reduction of computational complexit...
详细信息
This article proposes a new method for a determination of the two-dimensional distribution in systems with overflow traffic. The method proposed in the article offers a significant reduction of computational complexity as compared to two-dimensional convolution methods hitherto proposed. The proposed method is based on a determination of the two-dimensional distribution in the system with traffic overflow on the basis of the one-dimensional distribution. The accuracy of the proposed method, verified and validated in the course of relevant simulation experiments, supports its wider applicability in engineering practice to analyse and dimension multiservice networks with traffic overflow. The algorithm developed by the authors allows researchers to model systems with any type of traffic offered to primary resources.
The vehicle navigation and location system plays an essential role in all aspects of ITS. GPS/INS integrated navigation system has been widely used in land vehicle navigation. However, the performance of INS/GPS integ...
详细信息
ISBN:
(纸本)0780386434
The vehicle navigation and location system plays an essential role in all aspects of ITS. GPS/INS integrated navigation system has been widely used in land vehicle navigation. However, the performance of INS/GPS integrated system will severely degrade in urban canyon environments, where the GPS signals are often blocked by high-rise buildings, dense foliage and tunnels. To solve the problem, a pseudolite-augmented scheme is proposed, and a modified measurement model is presented, which uses the double difference of measured pseudo-ranges and INS estimated ranges. By employing this scheme, only two GPS signals are required to position a fix if using one pseudolite, which can be satisfied in,many urban canyon environments. Simulation results indicate that this approach can solve the urban canyon problem successfully.
The paper presents a model reference adaptive control (MRAC) of first and second order to control the nonlinear dynamics of an atomic force microscope (AFM) cantilever, which is operated in contact mode. The AFM is a ...
详细信息
ISBN:
(纸本)9781509011476
The paper presents a model reference adaptive control (MRAC) of first and second order to control the nonlinear dynamics of an atomic force microscope (AFM) cantilever, which is operated in contact mode. The AFM is a powerful tool to measure the topography of a sample at the scale of a few nanometers, where a small sharp tip supported in a micro cantilever scans the surface. In the contact mode the sample ' s topography is obtained by using the closed-loop control that holds the tip sample force constant. The nonlinear dynamics of the tip-sample system is very complex with different kinds of nonlinear forces that act between the tip and the sample. Here the dominated force depends on the distance tip-sample. In the present work we use a modified Hertz model to describe the nonlinear force when the distance tip-sample is less than 1 nm. First the complex nonlinear tip-sample system is controlled with a nonlinear MRAC of 1st order and after with a nonlinear MRAC of 2nd order. The results of both control strategies were compared in order to see which one gives a better control perfomance. Here a stability proof for both MRAC methods is present. A variety of simulation results are presented to demonstrate the efficacy of the proposed methods. The procedure is general and can be applied to any nonlinear system.
Senior High School (SHS) students need to have advanced mathematical thinking. Its growth can be measured through divergent problem solutions based on the teacher's scaffolding levels. The problems are: (1) How to...
详细信息
As an event-driven system,a supply chain network will face not only the uncertainties inside the supply chain,but also the unexpected events outside the supply chain network such as contingency,disruption,disaster and...
详细信息
As an event-driven system,a supply chain network will face not only the uncertainties inside the supply chain,but also the unexpected events outside the supply chain network such as contingency,disruption,disaster and *** uncertainties and unexpected events have negative impacts on the performance and economies of supply chain *** this paper,the Inoperability Input-Output Model(IIM) is deployed for assessing the impacts of disruptive events on supply chain networks under unsafe *** IIM is based on Wassily Leontief's input-output model which is capable of describing the propagation effects of disruptions to interdependent supply chain components. Besides assessing the propagating impacts of disruptive events for various supply chain components,the"inoperability"metric is also used in the IIM to present various perspectives of impact,including inoperability and economic loss, which can provide insights for risk management of supply chain *** inputs of IIM include failures due to accidents, natural hazards,or acts of *** output of IIM will be risk of inoperability that can be triggered by one or multiple failures due to complexity,accidents,or acts of *** inoperability indicates the inability of the system to perform its intended *** risk of inoperability is used to measure the joint effect of the probability (likelihood) and degree(percentage) of the inoperability of a *** example supply chain network is used to illustrate the application of IIM for systemic risk assessment and management of supply chains under unsafe environment.
The refractive index and birefringence of InxGa1-xN films grown on GaN layers were measured by prism coupling used in conjunction with multilayer optical waveguide analysis. Samples with x = 0.036, 0.049, 0.060, and 0...
详细信息
The refractive index and birefringence of InxGa1-xN films grown on GaN layers were measured by prism coupling used in conjunction with multilayer optical waveguide analysis. Samples with x = 0.036, 0.049, 0.060, and 0.066 were examined at the separate wavelengths of 442, 457.9, 476.5, 488, 514.5, 532, and 632.8 nm. The In fraction x was determined by Rutherford backscattering spectroscopy. Separate measurements of the film thicknesses were performed by cross-sectional field-emission scanning electron microscopy (FESEM). Film thickness information was required in order to constrain the numerical simulation used to solve for the ordinary (n(o)) and extraordinary (n(e)) refractive indices. We found that n(o) is a weak function of both x and wavelength for the InGaN layers and could only be well distinguished from GaN (x = 0) for the two shortest wavelengths used. On the other hand, n(e) for the InGaN layers was resolved from GaN for all the wavelengths and x values. The measurements for n(e) are limited by optical scattering observed at the shortest wavelengths and the higher values of x. Cross-sectional FESEM reveals that a source of this scattering is most likely triangular pits at the InGaN/GaN upper interface. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
暂无评论