Papers by Keyword: X-Ray Detection

Abstract: In order to solve production defects such as shrinkage and porosity inside a certain train coupler casting in Anhui Xinhong Machinery Co.,Ltd., the main reasons of defects are found through the process of CAE simulation analysis and physical X ray detection to determine the location and morphology of casting defects and to reflect the actual situation of coupler filling and solidification process. The main reasons are found as follows: uneven thickness of casting structure, insufficient original gating and feeding system and etc. Through the process optimization and apply multidimensional vibration, then test validation, the train coupler casting which meets the technical requirements has been successfully produced, ensuring the smooth mass production of the company. ProCAST numerical simulation results have confirmed the rationality of the proposed work in optimization process measures in reducing and eliminating the shrinkage defects.

Abstract: Selection of eight kinds of process parameters were performed on cast aluminum alloy ZL114 8mm thick plate cylinder and 5mm flat laser - arc hybrid welding, weld microstructure by comparing the morphology and size, considering the cost of internal defects and workmanship proposed to optimize the process parameters programs, microhardness and other properties of the weldment joints specimens tensile strength.

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: In light of the characteristic of thin-wall weld joint in X-ray image, Flaw-edge extraction algorithm and image enhancement algorithm which is based on mathematical morphology are proposed in the study of flaw extraction technique. Therefore, the area of flaw and background can be removed successfully. On this basis, there are two algorithms to identify different flaw types: one is that spatial domain transform to extract flaw edge for clack, the other one is mathematical morphology which is combined with iteration threshold to extract flaw edge for pore; Experimental results show that both of algorithms can implement flaw extraction and segmentation automatically, which is lay a good foundation for flaw feature parameter extraction and recognition.

Abstract: Detectors capable of withstanding high radiation environments for prolonged periods of exposure are essential for the monitoring of nuclear power stations and nuclear waste as well as for space exploration. Schottky diode X-ray detectors were exposed to high dose proton irradiation (1013 cm-2, 50 MeV) and changes in the detection resolution (spectroscopic full width half-maximum) have been observed. Using Deep Level Transient Spectroscopy (DLTS) and the degradation of the electrical characteristics of the diode, we have shown that radiation induced traps located in the upper half of the bandgap have reduced the concentration of carriers.

Abstract: Nanocrystalline powders of Lu2O3:Eu with activator content varying between 0.2%-10% were prepared using four different methods of synthesis. The products differed in their microstructure and crystallites sizes. Combustion of Lu(NO3)3 with urea produced strongly agglomerated material, most probably with significantly non-uniform distribution of the Eu3+ dopant. Replacing urea with glycine for the combustion produced only slightly agglomerated, voluminous, fluffy powder. Applying the Pechini technique resulted in significantly agglomerated powder while the homogeneous precipitation of Lu(OH)3 with urea at 90 °C and its subsequent decomposition to Lu2O3 at 650 °C resulted in a powder of perfectly spherical particles with a uniform size of about 130 nm with very low agglomeration. The efficiency of X-ray excited luminescence of our nanocrystalline Lu2O3:5%Eu was compared to that of the commercial microcrystalline Gd2O2S:Eu. It was found that the commercial phosphor performed four times more efficiently than our nanocrystalline powder. We consider this to be rather encouraging as the fabrication of our powder is not optimized yet. It seems that Lu2O3:Eu, even in nanocrystalline form, can perform much more efficiently which would make it a promising X-ray phosphor.