Rocks are likely to undergo spalling failure under dynamic loading.The fracture development and rock failure behaviours were investigated during dynamic tensile loading.Tests were conducted with a split-Hopkinson pres...Rocks are likely to undergo spalling failure under dynamic loading.The fracture development and rock failure behaviours were investigated during dynamic tensile loading.Tests were conducted with a split-Hopkinson pressure bar(SHPB)in four different impact loading conditions.Thin sections near failure surfaces were also made to evaluate the growth patterns of fractures observed by polarizing microscope.Scanning electron microscopy(SEM)was used to observe mineral grains on failure surfaces and to evaluate their response to loading and failure.The results indicate that the number of spalling cracks increases with increase in peak impact loads and that quartz sustains abundant intergranular fracturing.Cleavage planes and their direction relative to loading play a vital role in rock strength and fracturing.Separation along cleavage planes perpendicular to loading without the movement of micaceous minerals parallel to loading appears to be unique to the rock spalling process.展开更多
Through the 5-channel SWAES digital full waveform AE detector, the paper dealt with the fracture process of coal and rock samples under uniaxial compression. Using wavelet operations of multi-scale discrete analysis t...Through the 5-channel SWAES digital full waveform AE detector, the paper dealt with the fracture process of coal and rock samples under uniaxial compression. Using wavelet operations of multi-scale discrete analysis the pulses of a particular time period （points） and the space domain signal by numerical method were gotten, and the paper concluded that the signal singularity in load rupture had closely relations with fracture and uniaxial compression. The detected position and the actual breaking point only differed at one sample point, the relative error was 6.82%, and there was no accumulative error. Thus it provided an effective method to solve the problem of instability analysis of the signal singularity detection and coal-rock compression failure in the whole process.展开更多
AIM:To determine the risk factors for hepatocellular carcinoma(HCC) rupture,and report the management and long-term survival results of patients with spontaneous rupture of HCC.METHODS:Among 4209 patients with HCC who...AIM:To determine the risk factors for hepatocellular carcinoma(HCC) rupture,and report the management and long-term survival results of patients with spontaneous rupture of HCC.METHODS:Among 4209 patients with HCC who were diagnosed at Eastern Hepatobiliary Surgery Hospital from April 2002 to November 2006,200(4.8%) patients with ruptured HCC(case group) were studied retrospectively in term of their clinical characteristics and prognostic factors.The one-stage therapeutic approach to manage ruptured HCC consisted of initial management by conservative treatment,transarterial embolization(TACE) or hepatic resection.Results of various treatments in the case group were evaluated and compared with the control group(202 patients) without ruptured HCC during the same study period.Continuous data were expressed as mean ± SD or me-dian(range) where appropriate and compared using the unpaired t test.Categorical variables were compared using the Chi-square test with Yates correction or the Fisher exact test where appropriate.The overall survival rate in each group was determined using the Kaplan-Meier method and a log-rank test.RESULTS:Compared with the control group,more patients in the case group had underlying diseases of hypertension(7.5% vs 3.0%,P =0.041) and liver cirrhosis(87.5% vs 56.4%,P < 0.001),tumor size >5 cm(83.0% vs 57.4%,P < 0.001),tumor protrusion from the liver surface(66.0% vs 44.6%,P < 0.001),vascular thrombus(30.5% vs 8.9%,P < 0.001) and extrahepatic invasion(36.5% vs 12.4%,P < 0.001).On multivariate logistic regression analysis,underlying diseases of hypertension(P = 0.002) and liver cirrhosis(P < 0.001),tumor size > 5 cm(P < 0.001),vascular thrombus(P = 0.002) and extrahepatic invasion(P < 0.001) were predictive for spontaneous rupture of HCC.Among the 200 patients with spontaneous rupture of HCC,105 patients underwent hepatic resection,33 received TACE,and 62 were managed with conservative treatment.The median survival time(MST) of all patients with spontaneous rupture of HCC was 6 mo(range,1-72 mo),and the overall survival at 1,3 and 5 years were 32.5%,10% and 4%,respectively.The MST was 12 mo(range,1-72 mo) in the surgical group,4 mo(range,1-30 mo) in the TACE group and 1 mo(range,1-19 mo) in the conservative group.Ninety-eight patients in the control group underwent hepatic resection,and the MST and median diseasefree survival time were 46 mo(range,6-93 mo) and 23 mo(range,3-39 mo) respectively,which were much longer than that of patients with spontaneous rupture of HCC undergoing hepatic resection(P < 0.001).The 1-,3-,and 5-year overall survival rates and the 1-,3-and 5-year disease-free survival rates in patients with ruptured HCC undergoing hepatectomy were 57.1%,19.0% and 7.6%,27.6%,14.3% and 3.8%,respectively,compared with those of 77.1%,59.8% and 41.2%,57.1%,40.6% and 32.9% in 98 patients with-CONCLUSION:Prolonged survival can be achieved in selected patients undergoing one-stage hepatectomy,although the survival results were inferior to those of the patients without ruptured HCC.展开更多
基金the financial supports from the National Natural Science Foundation of China(Nos.51904335,51904333,11772357,51927808)。
文摘Rocks are likely to undergo spalling failure under dynamic loading.The fracture development and rock failure behaviours were investigated during dynamic tensile loading.Tests were conducted with a split-Hopkinson pressure bar(SHPB)in four different impact loading conditions.Thin sections near failure surfaces were also made to evaluate the growth patterns of fractures observed by polarizing microscope.Scanning electron microscopy(SEM)was used to observe mineral grains on failure surfaces and to evaluate their response to loading and failure.The results indicate that the number of spalling cracks increases with increase in peak impact loads and that quartz sustains abundant intergranular fracturing.Cleavage planes and their direction relative to loading play a vital role in rock strength and fracturing.Separation along cleavage planes perpendicular to loading without the movement of micaceous minerals parallel to loading appears to be unique to the rock spalling process.
基金Supported by the National Natural Science Foundation of China （51174157, 51174158）
文摘Through the 5-channel SWAES digital full waveform AE detector, the paper dealt with the fracture process of coal and rock samples under uniaxial compression. Using wavelet operations of multi-scale discrete analysis the pulses of a particular time period （points） and the space domain signal by numerical method were gotten, and the paper concluded that the signal singularity in load rupture had closely relations with fracture and uniaxial compression. The detected position and the actual breaking point only differed at one sample point, the relative error was 6.82%, and there was no accumulative error. Thus it provided an effective method to solve the problem of instability analysis of the signal singularity detection and coal-rock compression failure in the whole process.
基金Supported by National Science and Technology Major Project Foundation, No. 2008ZX10002-025
文摘AIM:To determine the risk factors for hepatocellular carcinoma(HCC) rupture,and report the management and long-term survival results of patients with spontaneous rupture of HCC.METHODS:Among 4209 patients with HCC who were diagnosed at Eastern Hepatobiliary Surgery Hospital from April 2002 to November 2006,200(4.8%) patients with ruptured HCC(case group) were studied retrospectively in term of their clinical characteristics and prognostic factors.The one-stage therapeutic approach to manage ruptured HCC consisted of initial management by conservative treatment,transarterial embolization(TACE) or hepatic resection.Results of various treatments in the case group were evaluated and compared with the control group(202 patients) without ruptured HCC during the same study period.Continuous data were expressed as mean ± SD or me-dian(range) where appropriate and compared using the unpaired t test.Categorical variables were compared using the Chi-square test with Yates correction or the Fisher exact test where appropriate.The overall survival rate in each group was determined using the Kaplan-Meier method and a log-rank test.RESULTS:Compared with the control group,more patients in the case group had underlying diseases of hypertension(7.5% vs 3.0%,P =0.041) and liver cirrhosis(87.5% vs 56.4%,P < 0.001),tumor size >5 cm(83.0% vs 57.4%,P < 0.001),tumor protrusion from the liver surface(66.0% vs 44.6%,P < 0.001),vascular thrombus(30.5% vs 8.9%,P < 0.001) and extrahepatic invasion(36.5% vs 12.4%,P < 0.001).On multivariate logistic regression analysis,underlying diseases of hypertension(P = 0.002) and liver cirrhosis(P < 0.001),tumor size > 5 cm(P < 0.001),vascular thrombus(P = 0.002) and extrahepatic invasion(P < 0.001) were predictive for spontaneous rupture of HCC.Among the 200 patients with spontaneous rupture of HCC,105 patients underwent hepatic resection,33 received TACE,and 62 were managed with conservative treatment.The median survival time(MST) of all patients with spontaneous rupture of HCC was 6 mo(range,1-72 mo),and the overall survival at 1,3 and 5 years were 32.5%,10% and 4%,respectively.The MST was 12 mo(range,1-72 mo) in the surgical group,4 mo(range,1-30 mo) in the TACE group and 1 mo(range,1-19 mo) in the conservative group.Ninety-eight patients in the control group underwent hepatic resection,and the MST and median diseasefree survival time were 46 mo(range,6-93 mo) and 23 mo(range,3-39 mo) respectively,which were much longer than that of patients with spontaneous rupture of HCC undergoing hepatic resection(P < 0.001).The 1-,3-,and 5-year overall survival rates and the 1-,3-and 5-year disease-free survival rates in patients with ruptured HCC undergoing hepatectomy were 57.1%,19.0% and 7.6%,27.6%,14.3% and 3.8%,respectively,compared with those of 77.1%,59.8% and 41.2%,57.1%,40.6% and 32.9% in 98 patients with-CONCLUSION:Prolonged survival can be achieved in selected patients undergoing one-stage hepatectomy,although the survival results were inferior to those of the patients without ruptured HCC.
