Cobalt ferrite (CoFe 2 O 4 ) nanoparticles were prepared through an auto-combustion method. The results of XRD show that the crystallite size of CoFe 2 O 4 nanoparticles increases from 57 to 105 nm with a slight change in lattice constant as the annealing temperature increases from 300 to 1200 C. The magnetic measurements by vibrating sample magnetometer (VSM) show that M s increases monotonously by increasing the annealing temperature from 300 to 1200 C and C hB and M s reached a maximum when annealing temperature is about 400 C due to the change of the grain size.

The accurate positioning of optical satellite image without control is the precondition for remote sensing application and small/medium scale mapping in large abroad areas or with large-scale images. In this paper, aiming at the geometric features of optical satellite image, based on a widely used optimization method of constraint problem which is called Alternating Direction Method of Multipliers (ADMM) and RFM least-squares block adjustment, we propose a GCP independent block adjustment method for the large-scale domestic high resolution optical satellite image – GISIBA (GCP-Independent Satellite Imagery Block Adjustment), which is easy to parallelize and highly efficient. In this method, the virtual "average" control points are built to solve the rank defect problem and qualitative and quantitative analysis in block adjustment without control. The test results prove that the horizontal and vertical accuracy of multi-covered and multi-temporal satellite images are better than 10 m and 6 m. Meanwhile the mosaic problem of the adjacent areas in large area DOM production can be solved if the public geographic information data is introduced as horizontal and vertical constraints in the block adjustment process. Finally, through the experiments by using GF-1 and ZY-3 satellite images over several typical test areas, the reliability, accuracy and performance of our developed procedure will be presented and studied in this paper.

No abstract

In this paper, a large signal circuit model of graphene field effect transistor (GFET) is described accurately by Verilog-A language, which is suitable for radio frequency circuit design and can be applied in HSPICE and ADS directly. Then two typical radio frequency (RF) circuits, frequency multiplier and mixer, are based on this GFET circuit model. The proposed circuits’ performance are analyzed respectively in 10GHz, 15GHz and 20GHz, and GFET’s application foreground in radio frequency area is discussed.