The interface of slab track laid in cold regions is prone to debonding under the coupling of freeze-thaw cyclesand temperature loads.Based on the composite specimen tests,the parameters of cohesive zone model were obt...The interface of slab track laid in cold regions is prone to debonding under the coupling of freeze-thaw cyclesand temperature loads.Based on the composite specimen tests,the parameters of cohesive zone model were obtained andused in a simulation model of CRTS III prefabricated slab track to study the interlayer damage.The results show that 1)the digital image correlation(DIC)technique can accurately capture the strain field changes on the interface of compositespecimens under splitting and shear loading;2)when the temperature gradient is−40℃/m−60℃/m,the interfacedamage of the slab track is minimal and presents different patterns of expansion under positive and negative temperaturegradients,each corresponding to damage of the cohesive element dominated by shear stress and normal tensile stress,respectively;3)the reduction of the elastic modulus at the concrete base after freeze-thaw inhibits interface damage andleads to a higher starting temperature gradient load,but cracking can occur on the concrete base after 150 freeze-thaws.For this reason,in the light of damage control of both the interface and concrete base,the elastic modulus of the concretebase is 54%or over that without freeze-thaw cycles.展开更多
AIM： To evaluate a series of patients with hepatocellular carcinoma （HCC） treated with several different protocols and devices. METHODS： We treated 138 patients [chronic hepatitis/ liver cirrhosis （Child-Pugh A/...AIM： To evaluate a series of patients with hepatocellular carcinoma （HCC） treated with several different protocols and devices. METHODS： We treated 138 patients [chronic hepatitis/ liver cirrhosis （Child-Pugh A/B/C）, 3/135 （107/25/3）] with two different devices and protocols： cool-tip needle [initial ablation at 60 W （standard method） （n = 37） or at 40 W （modified method） （n = 28）] or; ablation with a LeVeen needle using a standard single-step, full expansion （single-step） method （n = 39） or a multi-step, incremental expansion （multi-step） method. RESULTS： Eleven patients experienced rapid and scattered recurrences 1 to 7 mo after the ablation. Nine patients were treated by the cool-tip original protocol （60 W） （9/37 = 24%） and the other two by the LeVeen single-step method （2/39 = 5%）. The location of the recurrence was surrounding and limited to the site of ablation segment in three cases, and spread over one Iobule or both Iobules in the other eight cases. There was no recurrence in the patients treated with the modified cool-tip modified method （40 W） or the LeVeen multi-step method. CONCLUSION： There is a risk of rapid and scattered recurrence after RFA, especially when the standard cool- tip procedure is used. Because such recurrence would worsen the prognosis, we recommend that modified protocols for the cool-tip and LeVeen needle methods should be used in clinical practice.展开更多
Sinking columns are one of the most hazardous geological structures in north Chine typed coal fields. To understand the sinking column formation, to judge if the columns are hazardous or not, the inner circle mechanis...Sinking columns are one of the most hazardous geological structures in north Chine typed coal fields. To understand the sinking column formation, to judge if the columns are hazardous or not, the inner circle mechanism of groundwater in forming sinking columns in the relatively isolated areas was proposed according to the investigation on formation or distribution of sinking columns in some north China typed coal fields, such as Fengfeng, Xiangtai, Huaibei, Yangquan and so on. The heat generated by magma energized groundwater circulation and developed limestone karst in the relatively isolated areas. The CaCO3 solution accelerated by geothermal abnormality, the effect of high content of CO2 on dissolution and saturation of CaCO3 were discussed. Compared the forming conditions of the sinking columns developed in other coal mining areas in north China coal field, the paper deduced that the above factors collude karst development and sinking column formation, the columns in current geothermal areas are permeable and those in high coal rank areas or in paleo abnormally geothermal areas. The paper suggested that the sinking columns in the current abnormally geothermal areas were permeable, but those in the areas with high coal rank were not on contract.展开更多
基金Project(52425213)supported by the National Science Fund for Distinguished Young Scholars of ChinaProjects(52278461,52308467)supported by the National Natural Science Foundation of China+1 种基金Projects(2021YFF0502100,2021YFB2600900)supported by the National Key R&D Program of ChinaProject(2022JDTD0015)supported by the Sichuan Province Youth Science and Technology Innovation Team,China。
文摘The interface of slab track laid in cold regions is prone to debonding under the coupling of freeze-thaw cyclesand temperature loads.Based on the composite specimen tests,the parameters of cohesive zone model were obtained andused in a simulation model of CRTS III prefabricated slab track to study the interlayer damage.The results show that 1)the digital image correlation(DIC)technique can accurately capture the strain field changes on the interface of compositespecimens under splitting and shear loading;2)when the temperature gradient is−40℃/m−60℃/m,the interfacedamage of the slab track is minimal and presents different patterns of expansion under positive and negative temperaturegradients,each corresponding to damage of the cohesive element dominated by shear stress and normal tensile stress,respectively;3)the reduction of the elastic modulus at the concrete base after freeze-thaw inhibits interface damage andleads to a higher starting temperature gradient load,but cracking can occur on the concrete base after 150 freeze-thaws.For this reason,in the light of damage control of both the interface and concrete base,the elastic modulus of the concretebase is 54%or over that without freeze-thaw cycles.
文摘AIM： To evaluate a series of patients with hepatocellular carcinoma （HCC） treated with several different protocols and devices. METHODS： We treated 138 patients [chronic hepatitis/ liver cirrhosis （Child-Pugh A/B/C）, 3/135 （107/25/3）] with two different devices and protocols： cool-tip needle [initial ablation at 60 W （standard method） （n = 37） or at 40 W （modified method） （n = 28）] or; ablation with a LeVeen needle using a standard single-step, full expansion （single-step） method （n = 39） or a multi-step, incremental expansion （multi-step） method. RESULTS： Eleven patients experienced rapid and scattered recurrences 1 to 7 mo after the ablation. Nine patients were treated by the cool-tip original protocol （60 W） （9/37 = 24%） and the other two by the LeVeen single-step method （2/39 = 5%）. The location of the recurrence was surrounding and limited to the site of ablation segment in three cases, and spread over one Iobule or both Iobules in the other eight cases. There was no recurrence in the patients treated with the modified cool-tip modified method （40 W） or the LeVeen multi-step method. CONCLUSION： There is a risk of rapid and scattered recurrence after RFA, especially when the standard cool- tip procedure is used. Because such recurrence would worsen the prognosis, we recommend that modified protocols for the cool-tip and LeVeen needle methods should be used in clinical practice.
文摘Sinking columns are one of the most hazardous geological structures in north Chine typed coal fields. To understand the sinking column formation, to judge if the columns are hazardous or not, the inner circle mechanism of groundwater in forming sinking columns in the relatively isolated areas was proposed according to the investigation on formation or distribution of sinking columns in some north China typed coal fields, such as Fengfeng, Xiangtai, Huaibei, Yangquan and so on. The heat generated by magma energized groundwater circulation and developed limestone karst in the relatively isolated areas. The CaCO3 solution accelerated by geothermal abnormality, the effect of high content of CO2 on dissolution and saturation of CaCO3 were discussed. Compared the forming conditions of the sinking columns developed in other coal mining areas in north China coal field, the paper deduced that the above factors collude karst development and sinking column formation, the columns in current geothermal areas are permeable and those in high coal rank areas or in paleo abnormally geothermal areas. The paper suggested that the sinking columns in the current abnormally geothermal areas were permeable, but those in the areas with high coal rank were not on contract.
