Cogging torque and torque ripple reduction of a novel exterior-rotor geared motor

The reduction of cogging torque and torque ripple in permanent-magnet motors to suppress the vibration and acoustic noise is a major concern for motor designers. This study presents a novel exterior-rotor geared motor which integrates a brushless permanent-magnet (BLPM) motor with an epicyclic-type gear reducer to form a compact structural assembly without extra transmitting elements. One of the special features of the geared motor lies in the gear-teeth of the epicyclic-type gear reducer merged with the stator of the BLPM motor. The gear-teeth serve as the interfacial medium to connect the BLPM motor with the epicyclic-type gear reducer, which provides functions not only for transmission to achieve a desired speed ratio, but also effectively reduce the cogging torque and torque ripple of the geared motor. Five shape models of pole shoes with different values of the shoe depth and the shoe ramp are presented to effectively reduce the cogging torque and the torque ripple. With the aid of the finite-element analysis, shape model III of the geared motor performs better than the existing BLPM motor on the cogging torque with 87 % decreasing and the torque ripple with 23 % decreasing. Such a unique characteristic of the geared motor is of benefit to the widely applications on accurate motion and position control systems

Network Diversity and Social Cohesion in Creative Performance: A View of Communication Media Mix

Creative performance is a fundamental form of knowledge creation in knowledge intensive organizations. While some studies emphasize the importance of diversity on creative performance, others argue for the role of socially cohesive groups with strong third-party connections. To address the gaps in the literature, this study examines the influence of three attributes of dyadic ties (i.e., network diversity, social cohesion, and communication media mix) on creative performance. From the knowledge, social and technology perspectives, we empirically tested our model using a social network methodology with dyads working on knowledge intensive tasks. The results suggest that network diversity is positively associated with creative performance, and moderate level of social cohesion is preferred for creative performance. The findings also show that the influence of social cohesion on creative performance is weakened by the degree of communication media mix. Implications for research and practice are discussed with respect to creativity in organizations

Antidumping Petition: To File or Not To File

Given the “normal value†of a product as common knowledge in an import-competing market, the profitability of a home firm in filing an antidumping (AD) petition against its foreign rival is shown to depend on the marginal cost differential between the home and foreign firms. When the marginal cost differential is “significantly large,†the home firm's ability to put the foreign firm at the risk of an AD violation is limited. But when the marginal cost differential is “significantly small,†the home firm is able to increase its output and lower the price of the product below its normal value, putting the foreign firm in the situation of an illegal dumping. One interesting implication is that, relative to the case without an AD law, the home firm has a stronger incentive to undertake cost-reducing activities (e.g., R&D investment or the adoption of a more efficient technology) under the law.antidumping laws, antidumping duties, dumping margins

EFFECTS OF BASE OF SUPPORT AND VISUAL FEEDBACK ON STANDING BALANCE IN SUBJECTS WITH ANKLE SPRAIN

INTRODUCTION: Ankle sprain is arguably one of the most common injures in sport and can lead to significant impairment characterized by functional instability of the ankle. Base of support and visual feedback are two of the most important factors influencing the standing balance. Therefore, the purpose of this study was to investigate the effects of base of support and visual feedback on standing balance in subjects with and without ankle sprain

Quantum correlation measure in arbitrary bipartite systems

A definition of quantum correlation is presented for an arbitrary bipartite quantum state based on the skew information. This definition not only inherits the good properties of skew information such as the contractivity and so on, but also is effective and almost analytically calculated for any bipartite quantum states. We also reveal the relation between our measure and quantum metrology. As applications, we give the exact expressions of quantum correlation for many states, which provides a direct support for our result.Comment: 6 pages, 2 figures. Comments are welcom