Search

Capacitive sensors show promising applications for human–computer interface due to their potential capabilities of both pressure and proximity sensing. However, the sensitivity loss at large strain and the complicated process of fabrication technology limit related applications. Herein, inspired by gradient and hierarchical structures in biological systems and using porous materials with different stiffness, a capacitive flexible sensor with both proximity and pressure sensing abilities is proposed. Such hierarchical structures effectively reduce the attenuation of sensitivity as the pressure increases, realizing an ultrawide detection range with high sensitivity. A theoretical mathematical model is developed and the corresponding capacitive sensor is fabricated by using the high‐performance porous impregnated dust‐free paper as the electrode and expandable polyethylene (EPE)/loofah‐like polyurethane sponge (LPS) as double‐layer porous dielectric. This sensor has an ultrawide detection range up to 3000 kPa with a significantly low sensitivity loss of 0.0195% kPa−1 and the noncontact sensing mode reaches a sensing range up to 28 cm (0.122 cm−1). Notably, a strategy is provided to design the high sensitivity sensor over an ultrawide detection range from approaching to pressuring, and eventually its promising application is presented as human–computer interaction. [ABSTRACT FROM AUTHOR]

With the development of active noise and vibration control technology, there are increasing demands for active noise and vibration reshaping (ANVR) other than cancellation in the fields of active sound quality control, psychoacoustics, medical devices, military equipment, etc. The active noise equalizer (ANE) is one of the most popular ANVR methods. However, the ANE only controls (scales) the amplitude of the residual noise without considering the control of phase, and is unable to control frequency components that are excluded in primary noise. In this paper, we propose a more general and effective algorithm, called amplitude and phase control (APC), for ANVR, which can control amplitude and phase, simultaneously, of any interesting frequency component of the residual noise. Firstly, a modified active noise equalizer (MANE) algorithm with improved convergence is proposed based on the reference amplitude normalization and structure modification. Then, the APC algorithm is derived based on the MANE algorithm. Furthermore, numerical simulations and analytical investigations of the APC algorithm are conducted. Finally, case studies using experimental data are carried out. The multiple-harmonic primary noise was measured from a rotor test-platform and the secondary path model was identified according to a random vibration test on a shell structure. The results further verify the validity and robustness of the proposed APC algorithm. [ABSTRACT FROM AUTHOR]

In the present work, initial stage carbonization of γ-Fe(100) surface in C2H2 from 1000 K to 1600 K has been investigated by a molecular dynamic (MD) simulation, based on which the atomic mechanism of initial stage carbonization was provided. The absorption of C and H atoms during the carbonization process under different temperatures was analyzed. The related distributions of C and H atoms in carbonized layer were provided. The results manifested that higher temperature enhanced the inward diffusion of C and H, meanwhile caused the desorption of H atom. Furthermore, the effect of preset polycrystal γ-Fe on the carbonization process has been discussed, indicating a promoting role to the absorption and inner diffusion of C and H atom. The results of this study may support the optimal design of high-performance steel to some extent. [ABSTRACT FROM AUTHOR]