A study on carrier-removal techniques in fringe projection profilometry

This paper describes a comparison of several carrier-removal techniques normally used in fringe projection for surface shape measurement. The performance of various algorithms, including the necessity for manual intervention, the complexity in data recording, and the side effect on measurement accuracy, is evaluated. The applicability of nonlinear carrier removal and the restrictions on the direction of carrier fringe in various algorithms are also investigated in this paper. It is also shown that an advanced algorithm is able to achieve carrier removal with minimal manual intervention and significantly simplify the calibration process of a fringe projection system.     

Spin waves in nickel nanorings of large aspect ratio

The spin dynamics of high-aspect-ratio nickel nanorings in a longitudinal magnetic field have been investigated by Brillouin spectroscopy and the results are compared with a macroscopic theory and three-dimensional micromagnetic simulations. Good agreement is found between the measured and calculated magnetic field dependence of the spin wave frequency. Simulations show that as the field decreases from saturation, the rings switch from a "bamboo" to a novel "twisted bamboo" state at a certain critical field, and predict a corresponding dip in the dependence of the spin wave frequency on the magnetic field.     

The first three anisotropy constants of nickel

The technique of ferromagnetic resonance at 23 GHz has been used to determine the first three anisotropy constants of pure Ni down to 4.2K. A temperature and orientation dependent linewidth has also been observed.     

The use of circular optical grating for measuring angular rotation of mirrors

This paper explores the feasible use of circular optical grating for measuring the rotation of mirrors that are commonly found in micro-systems. Both theoretical and experimental results show that distortion of the circular grating that is projected onto the mirror surface is a simple function of the angular rotation of the mirror. The circular grating may readily be generated using a standard Michelson interferometer or an LCD projector. Through manipulating the distance between the interferometer and the mirror surface, the diameter of the optical grating may be varied. Furthermore, the additional use of a converging lens enables a significant reduction in the size of the grating: with simple laboratory facility, small circular grating of about 400 μm is achieved for use on micro-systems. With the use of more sophisticated optical elements, the angular rotation of even smaller micro-mirrors may be measured.     

Optical measurement of Young's modulus of a micro-beam

This paper presents an optical method based on the interference of light beams of equal path difference for the measurement of the Young's modulus of a micro-beam. An optical wedge which consists of an optical plate and a micro-beam which forms part of a micro-accelerometer is illuminated by a collimated monochromatic sodium light beam. Loading on the micro-beam is accomplished by a loading-pin mounted on a three-axis translation stage and the resulting interference fringe pattern is observed using a CCD camera connected to a computer. Loadings are recorded using a high-sensitive load cell which measures loads of up to 200 g with a resolution of 0.01 g. Test results conducted on micro-beams of different sizes show good repeatability and comparison of the experimental results with theory shows good agreement.     

One-step synthesis of pure Cu nanowire/carbon nanotube coaxial nanocables with different structures by arc discharge

Pure Cu nanowire/carbon nanotube (Cu@C) coaxial nanocables are one-step fabricated by arc discharge. The microstructure and morphology of the Cu@C nanocables are investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). XRD results reveal that the copper carbide nano-crystals were formed in the nanocables and it plays an important role in the growth of the Cu@C nanocables. As-prepared Cu@C nanocables exhibit three different structures, including well-filled Cu@C nanocables, symmetrically trifurcate Cu@C nanocables, and twice capsulated Cu@C nanocables. The fabrication of Cu@C nanocables with different structures offers more opportunities for the development of nanoelectronic devices. The formation mechanisms of Cu@C nanocables with different structures are discussed as well.     

Application of chalcone-based dithiocarbamate derivative incorporated sol–gel for the removal of Hg (II) ion from water

Journal of Sol-Gel Science and Technology - This study demonstrated the application of chalcone-based dithiocarbamate derivative as metal capturing ligand for the removal of mercury ion (Hg2+) in...     

Reductive Coupling of Diynes at Rhodium Gives Fluorescent Rhodacyclopentadienes or Phosphorescent Rhodium 2,2’‐Biphenyl Complexes

Reactions of [Rh(κ²‐O,O‐acac)(PMe₃)₂] (acac=acetylacetonato) and α,ω‐bis(arylbutadiynyl)alkanes afford two isomeric types of MC₄ metallacycles with very different photophysical properties. As a result of a [2+2] reductive coupling at Rh, 2,5‐bis(arylethynyl)rhodacyclopentadienes ( A ) are formed, which display intense fluorescence (Φ=0.07–0.54, τ=0.2–2.5 ns) despite the presence of the heavy metal atom. Rhodium biphenyl complexes ( B ), which show exceptionally long‐lived (hundreds of μs) phosphorescence (Φ=0.01–0.33) at room temperature in solution, have been isolated as a second isomer originating from an unusual [4+2] cycloaddition reaction and a subsequent β‐H‐shift. We attribute the different photophysical properties of isomers A and B to a higher excited state density and a less stabilized T₁ state in the biphenyl complexes B , allowing for more efficient intersystem crossing S₁→T_n and T₁→S₀. Control of the isomer distribution is achieved by modification of the bis‐ (diyne) linker length, providing a fundamentally new route to access photoactive metal biphenyl compounds.     

Phase retrieval in two-wavelength DSSI using a combined filtering method

Phase retrieval in two-wavelength DSSI (digital speckle shearing interferometry) using a combined filtering method is proposed for small deformation derivative measurement. A simultaneous two-wavelength illumination and 3-CCD camera are employed in the experimental setup. The proposed method, which uses a two-wavelength technique does not require the conventional spatial phase unwrapping and has the advantage of good noise suppression for phase retrieval. Experimental results obtained show that using the proposed combined filtering method sensitivity similar to the single wavelength technique can be achieved.