The aim of this paper is to investigate the damage cracking characteristics of rock and soil aggregate(RSA)by X-ray computed tomography(CT)under uniaxial compressive loading.The mean CT value for the region of interes...The aim of this paper is to investigate the damage cracking characteristics of rock and soil aggregate(RSA)by X-ray computed tomography(CT)under uniaxial compressive loading.The mean CT value for the region of interest(ROI)is used to analyze the cracking characteristics.Also,the mathematical morphology method based on the image threshold segmentation is used to obtain characteristic parameters of cracks to describe the cracking evolution of RSA.Results show that the elastic mismatch between rock blocks and soil matrix is the primary reason for RSA cracking.The mean CT value for the RSA specimen,rock block inclusions,and their adjacent soil regions decreases with the increasing stress level.However,it is more sensitive for block inclusions than soil regions.Using the image segmentation method,length,area and mean width of cracks obey to power function distribution.Crack statistical characteristics are closely related to the rock block’s distribution and morphology.These results may be useful to reveal the mesoscopic cracking mechanism,establish meso-damage evolution equation,and constitutive relation for RSA.展开更多
Acoustic emission test and CT scanning are important techniques in the study of coal crack propagation. A uniaxial compression test was performed on coal samples by integrating CT and acoustic emission. The test compa...Acoustic emission test and CT scanning are important techniques in the study of coal crack propagation. A uniaxial compression test was performed on coal samples by integrating CT and acoustic emission. The test comparison analyzes the acoustic emission load and CT images for an effective observation on the entire process, from crack propagation to the samples＇ destruction. The box dimension of the coal samples＇ acoustic emission series and the CT images were obtained through calculations by using the authors＇ own program. The results show that the fractal dimension of both the acoustic emission energy and CT image increase rapidly, indicating coal and rock mass has entered a dangerous condition. Hence, measures should be taken to unload the pressure of the coal and rock mass. The test results provide intuitive observation data for the coal meso-damage model. The test contributes to in-depth studies of coal or rock crack propagation mechanisms and provides a theoretical basis for rock burst mechanism.展开更多
Background: Detection of malignant liver mass is very important for the treatment modalities. Objective: The purpose of the present study was to establish the usefulness of CT scan in the diagnosis of malignant hepati...Background: Detection of malignant liver mass is very important for the treatment modalities. Objective: The purpose of the present study was to establish the usefulness of CT scan in the diagnosis of malignant hepatic mass. Methodology: This cross sectional study was carried out in the Department of Radiology and Imaging at Mymensingh Medical College Hospital (MMCH), Mymensingh, Banghabandhu Sheikh Mujib Medical University (B中央人民政府), Dhaka and Dhaka Medical College Hospital (DMCH), Dhaka during the period of 1st January 2006 to 31st December 2007. Patients admitted in the Department of Medicine and Department of Hepatobiliary of MMCH, B中央人民政府, and DMCH with the clinical diagnosis of fever, abdominal pain, anorexia, nausea/vomiting, loss of appetite, jaundice, weight loss and ascites were selected as study population. CT scan and histopathology were performed to all the patients. Result: A total number of 50 patients were recruited for this study. Mean age of all patients was 51.28 ± 14 years with a range of 17 year to 78 years. Among all patients 28 had multiple lesion, of them 71.4% was malignant and 28.6% was benign. On the other side 22 patients had solitary lesion, of them 36.4% was malignant and 63.6% was benign展开更多
文摘目的 探讨双期相双能量CT(dual-energy computed tomography,DECT)灌注成像在肺癌患者术前肺功能评估中的应用价值。方法 收集2022年11月—2024年6月于南京医科大学第一附属医院胸外科行手术治疗的ⅠA期非小细胞肺癌患者,术前均进行DECT灌注成像和肺功能检查(pulmonary function testing,PFT)。PFT观察指标包括通气功能指标如第一秒用力呼气量(forced expiratory volume in one second,FEV1)、用力肺活量(forced vital capacity,FVC)、1秒率(FEV1/FVC)、最大通气量(maximal voluntary ventilation,MVV),和弥散功能指标如一氧化碳弥散量(diffusing capacity for carbon monoxide,DLCO)、比弥散量(DLCO per liter of alveolar volume,DLCO/VA)。采用软件eXamine获得DECT灌注成像的定量参数,包括两肺及各肺叶的容积参数和灌注参数。分析两肺容积参数、灌注参数与患者的通气功能、弥散功能指标的相关性,以及各肺叶定量参数的差别。结果 吸气末相肺容积和双相容积差与FEV1、FVC呈强正相关(r=0.636,r=0.682,r=0.614,r=0.624,P<0.001),与MVV、DLCO呈中等程度正相关(r=0.499,r=0.514,r=0.549,r=0.447,P<0.001);呼气末相肺容积与DLCO/VA呈弱负相关(r=-0.295,P=0.026);容积比与FEV1、FVC、MVV、MVV占预测值百分比(MVV%)呈正相关(r=0.424,r=0.399,r=0.415,r=0.310,P<0.05);吸气末相碘含量与DLCO/VA占预测值百分比(DLCO/VA%)呈弱正相关(rs=0.292,P=0.030);呼气末相碘含量与FEV1、FVC、MVV、DLCO占预测值百分比(DLCO%)、DLCO/VA呈弱正相关(r=0.307,r=0.299,r=0.295,r=0.366,r=0.320,P<0.05),与DLCO呈中等程度正相关(r=0.439,P<0.001);吸气末相碘浓度与FEV1、FVC、MVV、MVV%呈负相关(rs=-0.407,rs=-0.426,rs=-0.352,rs=-0.277,P<0.05);呼气末相碘浓度与DLCO/VA呈中等程度正相关(r=0.403,P=0.002);碘浓度差和碘浓度比均与FEV1、FEV1占预测值百分比(FEV1%)、FVC、MVV、MVV%呈中等程度正相关(P<0.05)。肺容积、碘浓度比值均以左肺上叶最大,右肺中叶最小;肺容积差、肺容积比、肺内碘含量及肺内碘浓度差均以两肺下叶最高,右肺中叶最小。结论 双期相DECT灌注成像检查可以准确评估患者整体肺功能并量化区域肺功能。
基金supported by the National Natural Science Foundation of China(Grants Nos.41227901,41027001,and 41027001)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grants Nos.XDB10030000,XDB10030300 and XDB10050400)
文摘The aim of this paper is to investigate the damage cracking characteristics of rock and soil aggregate(RSA)by X-ray computed tomography(CT)under uniaxial compressive loading.The mean CT value for the region of interest(ROI)is used to analyze the cracking characteristics.Also,the mathematical morphology method based on the image threshold segmentation is used to obtain characteristic parameters of cracks to describe the cracking evolution of RSA.Results show that the elastic mismatch between rock blocks and soil matrix is the primary reason for RSA cracking.The mean CT value for the RSA specimen,rock block inclusions,and their adjacent soil regions decreases with the increasing stress level.However,it is more sensitive for block inclusions than soil regions.Using the image segmentation method,length,area and mean width of cracks obey to power function distribution.Crack statistical characteristics are closely related to the rock block’s distribution and morphology.These results may be useful to reveal the mesoscopic cracking mechanism,establish meso-damage evolution equation,and constitutive relation for RSA.
文摘Acoustic emission test and CT scanning are important techniques in the study of coal crack propagation. A uniaxial compression test was performed on coal samples by integrating CT and acoustic emission. The test comparison analyzes the acoustic emission load and CT images for an effective observation on the entire process, from crack propagation to the samples＇ destruction. The box dimension of the coal samples＇ acoustic emission series and the CT images were obtained through calculations by using the authors＇ own program. The results show that the fractal dimension of both the acoustic emission energy and CT image increase rapidly, indicating coal and rock mass has entered a dangerous condition. Hence, measures should be taken to unload the pressure of the coal and rock mass. The test results provide intuitive observation data for the coal meso-damage model. The test contributes to in-depth studies of coal or rock crack propagation mechanisms and provides a theoretical basis for rock burst mechanism.
文摘Background: Detection of malignant liver mass is very important for the treatment modalities. Objective: The purpose of the present study was to establish the usefulness of CT scan in the diagnosis of malignant hepatic mass. Methodology: This cross sectional study was carried out in the Department of Radiology and Imaging at Mymensingh Medical College Hospital (MMCH), Mymensingh, Banghabandhu Sheikh Mujib Medical University (B中央人民政府), Dhaka and Dhaka Medical College Hospital (DMCH), Dhaka during the period of 1st January 2006 to 31st December 2007. Patients admitted in the Department of Medicine and Department of Hepatobiliary of MMCH, B中央人民政府, and DMCH with the clinical diagnosis of fever, abdominal pain, anorexia, nausea/vomiting, loss of appetite, jaundice, weight loss and ascites were selected as study population. CT scan and histopathology were performed to all the patients. Result: A total number of 50 patients were recruited for this study. Mean age of all patients was 51.28 ± 14 years with a range of 17 year to 78 years. Among all patients 28 had multiple lesion, of them 71.4% was malignant and 28.6% was benign. On the other side 22 patients had solitary lesion, of them 36.4% was malignant and 63.6% was benign
