The structural evolution of tectonically deformed coals （TDC） with different deformational mechanisms and different deformational intensities are investigated in depth through X-ray diffraction （XRD） analysis on 3...The structural evolution of tectonically deformed coals （TDC） with different deformational mechanisms and different deformational intensities are investigated in depth through X-ray diffraction （XRD） analysis on 31 samples of different metamorphic grades （R ： 0.7%-3.1%） collected from the Huaibei coalfield. The results indicated that there are different evolution characteristics between the ductile and brittle deformational coals with increasing of metamorphism and deformation. On the one hand, with the increase of metamorphism, the atomic plane spacing （d002） is decreasing at step velocity, the stacking of the BSU layer （Lc） is increasing at first and then decreasing, but the extension of the BSU layer （La） and the ratio of La/Lc are decreasing initially and then increasing. On the other hand, for the brittle deformational coal, d002 is increasing initially and then decreasing, which causes an inversion of the variation of Lc and La under the lower-middle or higher-middle metamorphism grade when the deformational intensity was increasing. In contrast, in the ductile deformational coals, d002 decreased initially and then increased, and the value of L~ decreased with the increase of deformational intensity. But the value of La increased under the lower-middle metamorphism grade and increased at first and then decreased under the higher-middle metamorphism grade. We conclude that the degradation and polycondensation of TDC macromolecular structure can be obviously impacted during the ductile deformational process, because the increase and accumulation of unit dislocation perhaps transforms the stress into strain energy. Meanwhile, the brittle deformation can transform the stress into frictional heat energy, and promote the metamorphism and degradation as well. It can be concluded that deformation is more important than metamorphism to the differential evolution of the ductile and brittle deformational coals.展开更多
目的探讨大矩阵联合全模型迭代重建(Iterative Model Reconstruction,IMR)在人工智能(Artificial Intelligence,AI)检出肺结节中的应用价值,并比较滤波反投影(Filter Back Projection,FBP)、1024×1024 iDose^(4)、1024×1024 ...目的探讨大矩阵联合全模型迭代重建(Iterative Model Reconstruction,IMR)在人工智能(Artificial Intelligence,AI)检出肺结节中的应用价值,并比较滤波反投影(Filter Back Projection,FBP)、1024×1024 iDose^(4)、1024×1024 IMR重建算法对图像质量的影响。方法将临床怀疑肺结节要求行胸部薄层CT的60名患者纳入本次研究,所有患者扫描结束后对原始数据进行常规FBP、1024×1024 iDose^(4)、1024×1024 IMR算法重建,比较三组重建图像噪声标准差(Standard Deviation,SD)、信噪比(Signal to Noise Ratio,SNR)、对比噪声比(Contrast to Noise Ratio,CNR),比较三组图像在AI系统下对肺结节的检出率、真阳性数以及假阳性率的影响。结果FBP、1024×1024 iDose^(4)、1024×1024 IMR降低噪声能力依次提高,三组图像SNR、CNR按照此顺序依次提高,随着图像SNR、CNR的提高,图像的空间分辨率也随之提升,AI识别肺结节能力得到提升,AI识别肺结节敏感度IMR组相较于常规FBP组提高16.9%,同时假阳性率降低17.8%。结论大矩阵联合IMR技术能提高图像空间分辨率,在AI识别肺结节过程中可以提高对磨玻璃结节的检出能力,值得临床推广。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41030422, 40972131,40772135 and 41202120)the National Basic Research Program of China(Grant Nos.2009CB219601 and 2006CB202201)the China Postdoctoral Science Foundation Funded Project(2012M510590)
文摘The structural evolution of tectonically deformed coals （TDC） with different deformational mechanisms and different deformational intensities are investigated in depth through X-ray diffraction （XRD） analysis on 31 samples of different metamorphic grades （R ： 0.7%-3.1%） collected from the Huaibei coalfield. The results indicated that there are different evolution characteristics between the ductile and brittle deformational coals with increasing of metamorphism and deformation. On the one hand, with the increase of metamorphism, the atomic plane spacing （d002） is decreasing at step velocity, the stacking of the BSU layer （Lc） is increasing at first and then decreasing, but the extension of the BSU layer （La） and the ratio of La/Lc are decreasing initially and then increasing. On the other hand, for the brittle deformational coal, d002 is increasing initially and then decreasing, which causes an inversion of the variation of Lc and La under the lower-middle or higher-middle metamorphism grade when the deformational intensity was increasing. In contrast, in the ductile deformational coals, d002 decreased initially and then increased, and the value of L~ decreased with the increase of deformational intensity. But the value of La increased under the lower-middle metamorphism grade and increased at first and then decreased under the higher-middle metamorphism grade. We conclude that the degradation and polycondensation of TDC macromolecular structure can be obviously impacted during the ductile deformational process, because the increase and accumulation of unit dislocation perhaps transforms the stress into strain energy. Meanwhile, the brittle deformation can transform the stress into frictional heat energy, and promote the metamorphism and degradation as well. It can be concluded that deformation is more important than metamorphism to the differential evolution of the ductile and brittle deformational coals.
文摘目的探讨大矩阵联合全模型迭代重建(Iterative Model Reconstruction,IMR)在人工智能(Artificial Intelligence,AI)检出肺结节中的应用价值,并比较滤波反投影(Filter Back Projection,FBP)、1024×1024 iDose^(4)、1024×1024 IMR重建算法对图像质量的影响。方法将临床怀疑肺结节要求行胸部薄层CT的60名患者纳入本次研究,所有患者扫描结束后对原始数据进行常规FBP、1024×1024 iDose^(4)、1024×1024 IMR算法重建,比较三组重建图像噪声标准差(Standard Deviation,SD)、信噪比(Signal to Noise Ratio,SNR)、对比噪声比(Contrast to Noise Ratio,CNR),比较三组图像在AI系统下对肺结节的检出率、真阳性数以及假阳性率的影响。结果FBP、1024×1024 iDose^(4)、1024×1024 IMR降低噪声能力依次提高,三组图像SNR、CNR按照此顺序依次提高,随着图像SNR、CNR的提高,图像的空间分辨率也随之提升,AI识别肺结节能力得到提升,AI识别肺结节敏感度IMR组相较于常规FBP组提高16.9%,同时假阳性率降低17.8%。结论大矩阵联合IMR技术能提高图像空间分辨率,在AI识别肺结节过程中可以提高对磨玻璃结节的检出能力,值得临床推广。
