Advanced Materials Research Vol. 815

Abstract: X-ray nondestructive testing has a wide range of applications, which in materials testing, food testing, manufacturing, instrumentation, automotive parts and other fields having good performance. The paper mainly deals with low contrast X-ray digital images, image edge blur features and digital image preprocessing techniques of contrast. By a crack image taking geometric transformations, gray-scale transformations and image enhancement processing such as pretreatment technology airspace transforms, getting three options that have been able to effectively realize image denoising and enhancement. These three sets of processing solutions, to some extened, opening the image intensity distribution and making cracks sharper image segmentation is the foundation of subsequentence.

Abstract: Vibration results from situation when the inherent frequency close to the external exciting force during the operation of the motor, so accurate and effective calculation of the natural frequency of the motor has an important significance to damping noise. By numerical simulation model and the ANSYS finite element modal, the inherent frequencies were got of the motor and comparison results verify the effectiveness of the motor model. The effect of the modulus of elasticity of the softening layer between the motor and the ground to the inherent frequency was researched intensively, and puts forward related suggestions.

Abstract: Design an experimental method which can test the strength change of materials under the ultrahigh pressure, and a set of experimental data about the LY12 duralumin alloys materials yield strength and tensile strength are gained under the different ultrahigh pressure environment. The analysis result shows the strength of LY12 duralumin alloys will enhance. Because of effect of ultrahigh pressure, both yield strength and tensile strength increment of materials will approximately increase linearly. Beyond this, the method that can effectively build ultrahigh pressure environment has guidance significance for a real project.

Abstract: Low-cycle fatigue (LCF) tests were performed with different strain amplitudes from 0.4% to 1.2% at room temperature (RT) to investigate fatigue life and fracture morphology of TP347H austenitic stainless steels. The results show that there is initial cyclic hardening for a few cycles, followed by continuous softening until fatigue failure at all strain amplitudes in stress response curves. The fatigue life of the steels follows the strain-life Coffin-Manson law. Fracture morphology shows that fatigue cracks initiate from the specimen free surface instead of the interior of the specimen, and ductile fracture appears during LCF loading. More sites of crack initiation and quicker propagation rate of fatigue crack at high strain amplitudes than those at low strain amplitudes are responsible for reduced fatigue life with the increasing of strain amplitude.

Abstract: Restraint systems and protection devices, referred to as safety devices in this paper, are widely used in automobiles and aircraft for crashworthiness and safety. While such safety devices are designed to isolate, attenuate, and control the impact to the occupants, their performance for crashworthiness and safety may be ineffective or even counterproductive under certain circumstances.

Abstract: nfluencing factors of target products such as X phase, β-SiAlON phase and O-SiAlON phase of Inner Mongolia coal gangue carbothermal reduction and nitridation were researched by calculating the loss rate on ignition of specimens, and by means of XRD and SEM. During the carbothermal reduction and nitridation reaction of coal gangue, the loss rate on ignition of specimens rises with carbon reducer increasing, and keeping time has a little influence on the loss rate on ignition of specimens. If β-SiAlON is target phase, the yield from corundum is much higher than that from special grade bauxite. Corundum or bauxite is used as starting material, the yield of X phase is low and the highest yield is only 12.88%. For the carbothermal reduction and nitridation reaction of coal gangue, the appropriate addition of reducer carbon is 10%-16%, and temperature influence is larger. The reaction temperature over 1420°C and keeping time of 6h are beneficial to the formation of X phase, β-SiAlON and O-SiAlON.

Abstract: The composites of polycrystalline (La_1.85Sr_0.15CuO₄)_1-x(La_0.5Sr_0.5MnO₃)_x were prepared by solid state reaction method. By means of X-ray absorption spectroscopy, it is found that electrons can transit at grain boundaries from La_1.85Sr_0.15CuO₄ to La_0.5Sr_0.5MnO₃. Additional holes are formed in La_1.85Sr_0.15CuO₄ when the electron transitions happen. The experimental results of both X-ray absorption near edge structure and extended X-ray absorption fine structure excluded the possibility of that the electron transitions are induced by local lattice structure. According to the X-ray absorption experimental results of O K-edge of the La_1.85Sr_0.15CuO₄ and La_0.5Sr_0.5MnO₃ materials, a possible mechanism of the electron transitions and a phenomenological model of the band structure around Fermi level are proposed to explain the transition behavior.

Abstract: The rheological properties of HTPB mixed with boron (B) or agglomerated boron (TB) were investigated to explore the effect of the impurities of boron on the processing of propellant. The phase structure, morphology, and acidity of each sample were characterized by XRD, SEM and pH, respectively. The results show that rheological property of B/HTPB can be significantly improved by agglomerating boron with binder. Time has little effect on the viscosity of TB/HTPB while that of B/HTPB is a strong function of time. The viscosity of TB/HTPB decreases when the temperature increases from 303K to 343K, while that of B/HTPB decreases from 303K to 323K and then increases sharply after 323K. After agglomerating with binder, the T_onset of boron reduces from 1056K to 954K and T_p drops from 1076K to 998K. Compared with B2, the weight gain and oxidation degree of TB2 increases by 27% and 8.5%, respectively.

Abstract: In order to get clear cotton rustling sound signal, which will be analyzed to provide information at a certain stage of fabric processing for developing cotton products, before analysis of the data, it is the need for de-noising processing. The two de-noising methods, the median filtering method and the wavelet method are proposed in this paper. Their principles and algorithms are described. The cotton sound signals are exposed to interference and influence of some kinds of noise signal in the process of the data measured. So in practical applications, the two de-noising methods are used to process cotton rustling sound. The results of the process show the methods of processing the cotton sound signal are effective. The clear signal is getting to the next research.

Abstract: Tobacco planting in Guizhou existed many problems such as exceed planting area, irregularity in quality, imprecise in crop estimate and kinds of disaster monitoring etc. In this article, to solve these problems some new schemes were given. The satellite remote sensing technology was applied on tobacco planting monitoring in Fuquan city of Guizhou province for the first time combining with ERDAS, GPS and ARCGIS in this paper. It put forward a specific implementation plan. And this plan could provide technical helps very well in planting area statistics, growth monitoring and yield estimation of tobacco in Fuquan city.