Electric contributions to magnetic force microscopy response from graphene and MoS2 nanosheets

Magnetic force microscopy (MFM) signals have recently been detected from whole pieces of mechanically exfoliated graphene and molybdenum disulfide (MoS2) nanosheets, and magnetism of the two nanomaterials was claimed based on these observations. However, non-magnetic interactions or artefacts are commonly associated with MFM signals, which make the interpretation of MFM signals not straightforward. A systematic investigation has been done to examine possible sources of the MFM signals from graphene and MoS2 nanosheets and whether the MFM signals can be correlated with magnetism. It is found that the MFM signals have significant non-magnetic contributions due to capacitive and electrostatic interactions between the nanosheets and conductive cantilever tip, as demonstrated by electric force microscopy and scanning Kevin probe microscopy analyses. In addition, the MFM signals of graphene and MoS2 nanosheets are not responsive to reversed magnetic field of the magnetic cantilever tip. Therefore, the observed MFM response is mainly from electric artefacts and not compelling enough to correlate with magnetism of graphene and MoS2 nanosheets.

An SLA evaluator for multimedia content adaptation services

Content adaptation is used to adapt multimedia content to a version required by users. In the service-oriented scheme, adaptation functions are provided as services by third-party service providers. Clients pay for the consumed services and thus demand service quality. Providers advertise their services; each with varied quality-of-services (QoS). Some of these QoS however, may not be deliverable accordingly during the actual service execution due to heavy load. Thus, the provider should able to determine a current deliverable QoS before the service level agreement (SLA) is settled with the requesters. In this paper, we propose a strategy for service providers to evaluate incoming requests and capable of offering the new QoS to the requests potentially being initially rejected. The proposed strategy takes into account the current server load and requests' priority. We analysed the performance of the proposed strategy in terms of SLA settlement under various conditions. The results indicate that the proposed strategy performs well. © 2014 IEEE.