Investigation of L1_0 FePt-based soft/hard composite bit-patterned media by micromagnetic simulation

The soft/hard composite patterned media have potential to be the next generation of magnetic recording, but the composing modes of soft and hard materials have not been investigated systematically. L10 FePt-based soft/hard composite patterned media with an anisotropic constant distribution are studied by micromagnetic simulation. Square arrays and hexagonal arrays with various pitch sizes are simulated for two composing types： the soft layer that encloses the hard dots and the soft layer that covers the whole surface. It is found that the soft material can reduce the switching fields of bits effectively for all models. Compared with the first type, the second type of models possess low switching fields, narrow switching field distributions, and high gain factors due to the introduction of inter-bit exchange coupling. Furthermore, the readout waveforms of the second type are not deteriorated by the inter-bit soft layers. Since the recording density of hexagonal arrays are higher than that of square arrays with the same center-to-center distances, the readout waveforrns of hexagonal arrays are a little worse, although other simulation results are similar for these two arrays.

Research on Evolution of Goal-Driven Service Composition Patterns

With the development of Web service technology, using composite services to satisfy users' requirements has become an inevitable tendency. Goal changes caused by changing requirements of users may directly drive the corresponding evolution of service composition. However, most researches focus on how to compose services, and little efforts have been placed on how to evolve the composite services with changing requirements. In this paper, the service composition patterns are defined based on workflow patterns, and the changes of service composition patterns are analyzed according to changing goals. Finally, a case study is given to demonstrate the feasibility of the proposed approach.

Research on the architecture of submarine-fan lobes in the Niger Delta Basin,offshore West Africa

As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil-gas exploration in the world. Although a large amount of researches have been carried out on the architecture model of submarine lobes throughout the world, some controversies still exist on aspects such as the differential distribution of composite patterns and the quantitative relationships among different sedimentary settings. This paper, which took an oilfietd in the Niger Delta Basin offshore West Afnca as an example and utilized abundant core, welt-logging and seismic data comprehensively, established the semi- quantitative to quantitative architecture model for individual lobe and lobe complex. Results show that （1） A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and pro- grading types, showing relatively small lateral width but relatively large thickness. （2） Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation-progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeared gradually, and the amalgamated degree of the middle tabular sandbodies weakened as well with gradually developing of muddy interlayers. The formation of an individual lobe generally includes three stages as ＂rapid accumulation-progradation-aggradation＂.