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The gradual adaptation and possibility of divergence hinder the active noise control system from being applied to a wider range of applications. Selective active noise control has been proposed to rapidly reduce noise by selecting a pre-trained control filter for different primary noise detected without an error microphone. For stationary noise, considerable noise reduction performance with a short selection period is obtained. For non-stationary noise, more restrictive requirements are imposed on instant convergence, as it leads to faster tracking and better noise reduction performance. To speed up a selective filtered active noise control system, empirical wavelet transform is introduced here to accurately and instantaneously extract the frequency information of primary noise. The boundary of the first intrinsic mode function of random noises is extracted as the instant signal feature. Primary noise is attenuated immediately by picking the optimal pre-trained control filter labeled by the nearest boundary. The storage requirement for a pre-trained control filter library is reduced. Instant control is obtained, and the instability caused by output saturation is overcome. With more concentrated energy distribution, better noise reduction performance is achieved by the proposed algorithm compared to conventional and selective active noise control algorithms. Simulation results validate these advantages of the proposed algorithm. [ABSTRACT FROM AUTHOR]

• Built an active noise control window on the top- hung window frame in a real dormitory room. • Investigate how the noise control performance of this ANC system is affected by controllable system variations. • Figure out the optimal system setup. • Investigate the sensitivity of the ANC window system over the secondary path variation caused by varying window opening status. Urban noise mitigation experiment through active noise control window is not commonly carried out in in situ urban setting. This paper outlines our experimental settings of performing active noise control across the open aperture of the top-hung window frame in a dormitory room. A multi-channel adaptive filtered-x least mean square method is implemented in real-time. Experiments and analyses are carried out to investigate how the noise reduction performance of this active noise control window system is affected by the number of reference microphones, the distance between reference microphones and secondary sources, and the distributions of error microphones under practical restrictions of the real system implementation. Variation of the secondary path estimation is another important consideration in active noise control system design. Real-time experiments are carried out to investigate the sensitivity of the ANC window system over the secondary path variation caused by varying window opening status, and whether a generalised secondary path measured in one window opening setting can be applied to other window opening conditions. [ABSTRACT FROM AUTHOR]

Looks at the discovery of high-T superconducters which experiments has revealed that phase diagrams of La...-...Sr...CuO... and YBa...Cu...O...+... resemble each other. Indepth look at the experiment; Details on the results and discussion.

Transmission electron micrographs of a multilayer film consisting of 360 alternating layers of plasma deposited hydrogenated amorphous silicon and silicon nitride show that each 28-Å-thick layer is remarkably flat and uniform. Within the first 1000 Å near the glass substrate the regular growth of the layers is disturbed by instabilities which resemble dislocations in the layering. Electron microscopy of compositional layering may prove to be an important tool for studying the growth mechanism during plasma deposition. [ABSTRACT FROM AUTHOR]

Most of the non-acoustic methods for towed array shape estimation are based on the incorrect original Paidoussis equation. A comparison between solution to the original and revised Paidoussis equation is made to prove the significance of utilising the latter. In addition, considering relative characteristics of the revised Paidoussis equation and the critical point which exists on the cylinder, the minimum length of damping section added at the end of the cylinder is derived. [ABSTRACT FROM AUTHOR]

Abstract: Orthorhombic boron nitride (oBN) nanowires with diameters ranging from 50–100nm and lengths up to several tens micrometers was synthesized in a simple hydrothermal route. The as prepared sample has been characterized as oBN by SEM, HRTEM and SADP. Based on careful observation, unique bamboo-like nanostructures was found in the products. A probable formation mechanism of bamboo-like nanowires was discussed. [Copyright &y& Elsevier]

Abstract: Gold nanoparticles supported on carbon nanotubes (CNTs) were obtained by using electroless plating technique. High-resolution transmission electron microscopy evidenced the high-density and homogeneous dispersion of spherical gold nanoparticles on the outer surfaces of the carbon nanotubes, with a sharp particle size distribution centered at around 3–4 nm of diameter. The resultant hybrid nanostructures have potential application for being used as novel gold nanocatalysts. [Copyright &y& Elsevier]

The electron structure of the typical calcium phosphate ceramic, hydroxyapatite (OHAP), is investigated by the use of the tight-binding recursion method. The local density of states, partial density of states, structural energy and charge transfer are calculated, as well as the interatomic energy between atoms and bond order integral. Some physical and chemical properties of OHAP are discussed. The calculated results show that both the OH group and the PO4 group can be regarded as individual structure units in OHAP owing to strong interaction between atoms. Meanwhile, the atomic structure of a grain boundary is determined on the basis of the near-coincidence site lattice model with consideration of the bond length in the crystal and the lattice distortion. The electron structure and energy of a Sigma = 7 grain boundary are calculated. The results show that a grain boundary with a slight lattice misfit has a lower energy. [ABSTRACT FROM AUTHOR]

Analyzes the structure of polyhydro particles using HRTEM and the energy spectrum method. Preparation of nanocrystalline transition; Storage of hydrogen in nano transition metal particles; Ability of this stored hydrogen; Details on the structure of the shell and the core of hydrogen storage particles.

Abstract: Pure copper nanocrystallites and cuprous oxide nanorods have been synthesized via solvothermal treatment of CuSO4 or CuSO4·5H2O and NaOH in pure ethanol and mixed solution of ethanol and deionized water at 140 °C for 10 h, respectively. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to investigate the different morphologies of the as-synthesized products. X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) were applied to characterize the composition and crystal phases of the products. It was proposed that the reducibility of ethanol was influenced by temperature and the addition of deionized water in the formation of different phases, which were realized by carefully controlling the experimental conditions. [Copyright &y& Elsevier]

Abstract: Gold nanoparticles supported on carbon nanotubes were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3–4nm in diameter. The results presented in this work will probably provide new catalysts with better performances. [Copyright &y& Elsevier]

Cobalt-filled carbon nanotubes were prepared in situ in the decomposition of benzene over Co/silica-gel catalysts. Unlike the previous reports, in our experiments, the catalysts need not pre-reduced. Transmission electron microscopy (TEM) investigation showed that the as-made products contained abundance of carbon nanotubes (CNTs) and almost 100% of them were filled with metallic nanoparticles or nanorods. High-resolution TEM (HRTEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Co inside the nanotubes. The encapsulated Co was further identified as alpha-Co with face-centered cubic (fcc) structure, which frequently consists of twinned boundaries. Based on the experimental results, a possible growth mechanism of the Co-filled nanotubes was proposed. [Copyright &y& Elsevier]

Cobalt-filled carbon nanotubes (CNTs) were prepared in situ in the decomposition of benzene over Co/silica-gel catalysts. Transmission electron microscopy (TEM) investigation showed that the products contained abundance of carbon nanotubes and most of them were filled with metallic nanoparticles or nanorods. High-resolution TEM (HRTEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Co inside the nanotubes. The encapsulated Co was further identified as α-Co with fcc structure, which frequently consists of twinned boundaries. Based on the experimental results, a possible growth mechanism of the Co-filled nanotubes was proposed. [Copyright &y& Elsevier]

• Block coordinate descent notably reduces complexity without degrading performance. • Momentum integration into block coordinate descent greatly improves convergence rate. • Block coordinate descent attains similar noise reduction to McFXLMS in real-time. Multichannel active noise control (MCANC) is widely regarded as an effective solution to achieve a significantly large noise-cancellation area in a complicated acoustic field. However, the computational complexity of MCANC algorithms, such as the multichannel filter-x least mean square (McFxLMS) algorithm, grows exponentially with an increased channel count. Many modified algorithms have been proposed to alleviate the complexity but at the expense of noise reduction performance. Till now, the trade-off between computational complexity and noise reduction performance has limited the practical implementation of MCANC. The block coordinate descent McFxLMS (BCD McFxLMS) algorithm proposed in this paper substantially reduces the computation cost of an MCANC system, while maintaining the same noise reduction performance as the conventional McFxLMS algorithm. Furthermore, a momentum mechanism is integrated into the BCD McFxLMS in practice to improve the convergence speed. The simulation and experimental results validate the effectiveness of proposed algorithms when dealing with noise in a realistic environment. [ABSTRACT FROM AUTHOR]