13,890 research outputs found
Effect of hot rolling reduction on microstructures and textures of grain oriented silicon steel
The effect of hot rolling reduction on microstructures and textures of grain oriented silicon steel was studied by optical microscopy (OM), zeiss ultra 55 Scanning electron microscope (SEM) and Electron backscatter diffraction (EBSD) technique respectively. The results indicate that the effect of hot rolling reduction on grain size of hot rolled and normalized sheets in surface layer is great, while the effect on grain size of primary recrystallized grain is little. The shear zone thickens with the finishing reduction decreases, moreover strong {111} and {110} textures can be obtained in hot rolled sheets. Combined with the previous research conclusions, it can be found that the rolling process of oriented silicon steel is contributed to the formation of texture, while the recrystallization process reduces the sharpness of the texture
A study on inclusion formation mechanism in alpha-LiIO sub 3 crystals
The spatial distribution of inclusions in alpha-LiIO3 crystals by means of an argon laser beam scanning technique is studied. The effects of crystal dimensions and solution fluid flow on the inclusion formation in the alpha-LiIO3 crystals were observed. It was further shown that the fluid flow plays an important role in the formation of inclusions. The results obtained were further applied and verified by growing a perfect alpha-LiIO3 single crystal. An experimental foundation for further theoretical studies on the causes of inclusions may be provided
Distribution of Spectral Lags in Gamma Ray Bursts
Using the data acquired in the Time To Spill (TTS) mode for long gamma-ray
bursts (GRBs) collected by the Burst and Transient Source Experiment on board
the Compton Gamma Ray Observatory (BATSE/CGRO), we have carefully measured
spectral lags in time between the low (25-55 keV) and high (110-320 keV) energy
bands of individual pulses contained in 64 multi-peak GRBs. We find that the
temporal lead by higher-energy gamma-ray photons (i.e., positive lags) is the
norm in this selected sample set of long GRBs. While relatively few in number,
some pulses of several long GRBs do show negative lags. This distribution of
spectral lags in long GRBs is in contrast to that in short GRBs. This apparent
difference poses challenges and constraints on the physical mechanism(s) of
producing long and short GRBs. The relation between the pulse peak count rates
and the spectral lags is also examined. Observationally, there seems to be no
clear evidence for systematic spectral lag-luminosity connection for pulses
within a given long GRB.Comment: 20 pages, 4 figure
A modified Mahalanobis distance for human detection in out-door environments
This paper proposes a novel method for human detection from static images based on pixel structure of input images. Each image is divided into four parts, and a weight is assigned to each part of the image. In training stage, all sample images including human images and non-human images are used to construct a Mahalanobis distance map through statistically analyzing the difference between the different blocks on each original image. A projection matrix will be created with Linear Discriminant Method (LDM) based on the Mahalanobis distance map. This projection matrix will be used to transform multidimensional feature vectors into one dimensional feature domain according to a pre-calculated threshold to distinguish human figures from non-human figures. In comparison with the method without introducing weights, the proposed method performs much better. Encouraging experimental results have been obtained based on MIT dataset and our own dataset. © 2008 IEEE
- …