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The authors propose a dual-energy approach to reduce cone-beam artefacts in a circular orbit cone-beam computed tomography (CT) system. When there exist multiple dense structures within a large cone angle, two-pass algorithm is ineffective for reducing cone-beam artefacts because high-density materials are incorrectly segmented with simple thresholding. The proposed algorithm utilises projection data obtained with dual-energy X-ray spectra to estimate projections of the high-density materials from multi-density anatomical structures. Using bone and water as two of basis functions, the projection data of bone materials can be precisely estimated via dual-energy scans. Then, bone-only images are reconstructed by a constrained total-variation minimisation-based iterative algorithm. The reconstructed bone images are used to generate cone-beam artefacts and the final corrected images are acquired by subtracting the generated cone-beam artefacts from the original Feldkamp, Davis, and Kress images. The proposed method was validated using an extended cardiac-torso phantom with complex vertebral anatomy and compared with the two-pass algorithm. The results show that the proposed method restores distorted bony structures and intensity values, especially in regions with large cone angles. A qualitative evaluation of the mean-squared errors and structural similarities demonstrates the effectiveness of the proposed method compared to the two-pass algorithm. [ABSTRACT FROM AUTHOR]

This Letter proposes a new two‐sample excess loop delay compensation in continuous‐time delta‐sigma modulators using time‐shifted differentiated digital‐to‐analogue converter (DAC). This is done by using the information inherently available but ignored in the conventional methods, and therefore no additional hardware is required. Simulation results and mathematical analysis are provided to verify the effectiveness of the proposed structure. [ABSTRACT FROM AUTHOR]

A new method for quantisation error extraction in continuous‐time delta–sigma modulators (CTDSMs) is proposed. The proposed method avoids the use of additional active components such as transconductors and opamps and uses only passive components. Instead, the virtual ground of the second stage integrator is used as a summing node and is utilised to extract the quantisation error. Thus, multi‐stage CTDSM can be implemented in a power and area efficient way. [ABSTRACT FROM AUTHOR]

A delay‐based noise cancelling sturdy multi‐stage noise shaping (MASH) structure that cancels the first‐stage quantisation error is presented. Thus, a smaller number of bits can be used for the first‐stage quantiser without degrading the overall performance. In addition, the proposed structure improves stability with respect to maximum applicable input by removing the first‐stage quantisation error from the first loop. [ABSTRACT FROM AUTHOR]

A new approach for a multi‐class steady‐state visual‐evoked potential (SSVEP)‐based brain–computer interface (BCI) is proposed. It was demonstrated through preliminary experiments that spatial patterns of SSVEP responses recorded using high‐density electroencephalography while presenting pattern reversal checkerboard stimuli with different spatial patterns can be classified with fairly high accuracy. The average classification accuracies in two of the three subjects were 91.7% (12‐class) and 93.3% (15‐class), suggesting that the proposed visual stimulation can potentially be used for multi‐class SSVEP‐based BCI. [ABSTRACT FROM AUTHOR]

Pentacene organic thin-film transistor (OTFT) with HfYO as gate dielectric has been fabricated at room temperature on adhesive flexible vacuum tape and shows high performance. The threshold voltage is as low as -1.77 V due to the high-κ gate dielectric employed. A small sub-threshold swing (SS) of 0.145 V/dec indicates good interface between the gate dielectric and pentacene film. Atomic force microscopy (AFM) reveals that large pentacene gains form on the HfYO gate dielectric, leading to a high carrier mobility of 0.236 cm2V-1s-1. These good results suggest that the adhesive vacuum tape can be used as the substrate for adhesive flexible OTFT, and HfYO is a promising gate dielectric for high-performance pentacene OTFT. [ABSTRACT FROM AUTHOR]