A highly integrated fibre-optic sensor with regenerated fibre Bragg grating (RFBG) and a micro Fabry-Pérot (MFP) is proposed and demonstrated for simultaneous measurement of temperature and strain under high temperature (> 600 °C). The MFP is fabricated by using a 157 nm fluorine gas (F2) laser to micromachine the core of a standard optical fibre. The RFBG is fabricated by regenerating a seed grating written over the Fabry-Pérot. Since the MFP and RFBG have different sensitivity coefficients, their combination can be used to realise simultaneous measurement of temperature and strain. It is believed that such a high-temperature strain sensor could find important applications in many areas where simultaneous measurement of temperature and strain under high temperature is required.
In order to seek the reasonable Laser forming process parameters of TC4 titanium alloy, and to control forming quality,
based on the element life and death technique of finite element methods (FEM), detailed numerical simulation of single
track and multi-layer temperature field of TC4 titanium alloy during laser rapid forming was conducted with ANSYS
parametric design language (APDL). And get the distribution of temperature field and temperature gradients. The
calculated results show that the distribution of temperature field changed with the movement of laser beams and the heat
affected area have been expanded along with the increase of the scanning time, temperature increase gradually and
temperature gradients obviously changed in molten pool area. The temperature gradients in sample are mainly along
deposition direction. In the end, carry on an experimentation research testing and verifying according to the simulation
parameters, proof that the results can meet the actual situation analysis results, and forming a sample with good
Traditionally, 3D models, even so called solid ones, can only represent the object's surface information, and the interior is regarded as homogeneous. In most applications, it is necessary to represent the interior structures and attributes of an object, such as materials, density and color, etc. Surface model is incapable of bearing this task. In this case, voxel model is a good choice. Voxelization is the process of converting a geometrically represented 3D object into a three dimensional volume of dataset. In this paper, an algorithm is proposed to voxelize the polygonal meshes ported from current CAD modeling packages into volume datasets based on the easily indexing property of Octree structure. The minimal distance to the feature voxel (or voxels) is taken as criterion to distribute different material compositions to get a new kind of material called FGM (functionally graded material), which is suitable for the interface of RPM (Rapid Prototyping Manufacturing).
The design of Functional Graded Material (FGM) and the visualization relative technology are described briefly in this paper, such as the organization ofthe 3D regular or irregular data ,isoline and the isosurface technique. It is proved that the visualization is used in the design of Functional Graded Material (FGM),which makes the material design is more intuitive and more reasonable.
Zeeman splitting of donor levels in silicon proportional to the square of the magnetic field are observed. Theoretical discussion indicated that this phenomenon is induced by mixing of donor states created by an external magnetic field.
Magneto-photoconductivity of n-type Hg0.622Cd0.378Te/CdTe/GaAs samples grown by molecular-beam epitaxy (MBE) was measured in the wavenumber region of 400 - 5000 cm-1 at 4.2 K by the Fourier transform magneto-optics system. The highest magnetic field used was as high as 8 Tesla. The experimental results were interpreted in terms of quasi-Ge model of Pidgeon and Brown. Our results show that this model is still valid for Hg1-xCdxTe with composition x as high as 0.378.
The IR transmission spectra for HgCdTe/CdTe/GaAs multilayers grown by molecular-beam epitaxy were measured in the wavenumber region of 600 cm-1 - 4000 cm-1 at 300 K and 77 K. The transmission spectra were calculated taking the thickness d1 of MCT layer and the thickness d2 of CdTe layer as fitting parameters in the energy range from 600 cm-1 to 300 cm-1 below the energy gap Eg assuming the existence of abrupt interfaces between the neighboring layers. The values of d1 and d2 obtained by fitting the IR transmission spectra are in good agreement with that by transmission electron microscopy (TEM) measurement. The accurate absorption coefficient spectra were obtained and discussed in the energy region equivalent to 0.9 Eg to 4000 cm-1 taking into account the interference effects.