To study a new shaped charge of perforator, the jet formation and penetration processes in concrete targets are simulated numerically by using LS-DYNA finite element analysis software. The results show that the cylind...To study a new shaped charge of perforator, the jet formation and penetration processes in concrete targets are simulated numerically by using LS-DYNA finite element analysis software. The results show that the cylindrical liner can form jet and most materials on top of liner form the tip of jet, while the others form the tail of jet. The jet has a better continuity, and the ratio of cumulative jet length to the liner diameter can reach to 7.56. Furthermore, the ratio of bore diameter to the liner diameter is from 0.36 and 1, and the ratio of penetration depth to the liner diameter can be up to 5.5.展开更多
In order to obtain the perforation depth, the three zones with different permeability because of plastic deformation and fluid invasion were studied based on related theories. The study shows that the calculation of p...In order to obtain the perforation depth, the three zones with different permeability because of plastic deformation and fluid invasion were studied based on related theories. The study shows that the calculation of perforation depth should take account of not only damaged zone, but also plastic zone, because the plastic zone has much lower permeability. The required minimum perforation depth was obtained by making the solution of elastic/plastic equations, and the factors affecting perforation depth were analyzed accordingly.展开更多
目的:探讨连接智能手机的红外热成像技术在皮瓣移植围手术期中的应用价值。方法:2018年1月-2019年1月,笔者科室使用连接智能手机的便携式红外热像仪(FLIR ONE Pro),在10例患者皮瓣移植术围手术期对皮瓣及其轴形血管、穿支血管进行拍摄,...目的:探讨连接智能手机的红外热成像技术在皮瓣移植围手术期中的应用价值。方法:2018年1月-2019年1月,笔者科室使用连接智能手机的便携式红外热像仪(FLIR ONE Pro),在10例患者皮瓣移植术围手术期对皮瓣及其轴形血管、穿支血管进行拍摄,并应用FLIR Tools软件进行分析,同时在术中对穿支血管及轴形血管进行验证,计算热成像技术预测皮瓣坏死的敏感性、特异性、准确性、阳性预测值、阴性预测值。结果:本组10例患者有11处软组织缺损,均行皮瓣修复。热成像仪检测结果显示,8处皮瓣血供良好,3处皮瓣血供不佳。血供良好的8处皮瓣,术后观察到1处皮瓣出现部分坏死。血供不佳的3处皮瓣,术后观察到2处皮瓣出现远端表浅坏死,1处皮瓣术后血供好,未发生坏死。在此基础上计算热成像技术预测皮瓣坏死的敏感性为66.7%(2/3),特异性为87.5%(7/8),准确性为81.8%(9/11),阳性预测值为66.7%(2/3),阴性预测值为87.5%(7/8)。术前探测穿支血管16支,术中证实13支;探测10支血管链,术中证实10支血管链。结论:连接智能手机的红外热成像技术在术前探查血管穿支、血管链用于辅助皮瓣设计,术中术后监测皮瓣的皮温、血运以预测、预防皮瓣的坏死方面具有较高的客观性及有效性,可客观有效地辅助外科医生设计皮瓣、评估皮瓣血运,值得临床推广应用。展开更多
Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress i...Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress interference,which results in uneven fracture propagation. It is common practice to use “balls” to temporarily plug fractureopenings in order to lessen liquid intake and achieve uniform propagation in each cluster. In this study, a diameteroptimization model is introduced for these plugging balls based on a multi-cluster fracture propagationmodel and a perforation dynamic abrasion model. This approach relies on proper consideration of the multiphasenature of the considered problem and the interaction force between the involved fluid and solid phases. Accordingly,it can take into account the behavior of the gradually changing hole diameter due to proppant continuousperforation erosion. Moreover, it can provide useful information about the fluid-dynamic behavior of the consideredsystem before and after plugging. It is shown that when the diameter of the temporary plugging ball is1.2 times that of the perforation hole, the perforation holes of each cluster can be effectively blocked.展开更多
文摘To study a new shaped charge of perforator, the jet formation and penetration processes in concrete targets are simulated numerically by using LS-DYNA finite element analysis software. The results show that the cylindrical liner can form jet and most materials on top of liner form the tip of jet, while the others form the tail of jet. The jet has a better continuity, and the ratio of cumulative jet length to the liner diameter can reach to 7.56. Furthermore, the ratio of bore diameter to the liner diameter is from 0.36 and 1, and the ratio of penetration depth to the liner diameter can be up to 5.5.
文摘In order to obtain the perforation depth, the three zones with different permeability because of plastic deformation and fluid invasion were studied based on related theories. The study shows that the calculation of perforation depth should take account of not only damaged zone, but also plastic zone, because the plastic zone has much lower permeability. The required minimum perforation depth was obtained by making the solution of elastic/plastic equations, and the factors affecting perforation depth were analyzed accordingly.
文摘目的:探讨连接智能手机的红外热成像技术在皮瓣移植围手术期中的应用价值。方法:2018年1月-2019年1月,笔者科室使用连接智能手机的便携式红外热像仪(FLIR ONE Pro),在10例患者皮瓣移植术围手术期对皮瓣及其轴形血管、穿支血管进行拍摄,并应用FLIR Tools软件进行分析,同时在术中对穿支血管及轴形血管进行验证,计算热成像技术预测皮瓣坏死的敏感性、特异性、准确性、阳性预测值、阴性预测值。结果:本组10例患者有11处软组织缺损,均行皮瓣修复。热成像仪检测结果显示,8处皮瓣血供良好,3处皮瓣血供不佳。血供良好的8处皮瓣,术后观察到1处皮瓣出现部分坏死。血供不佳的3处皮瓣,术后观察到2处皮瓣出现远端表浅坏死,1处皮瓣术后血供好,未发生坏死。在此基础上计算热成像技术预测皮瓣坏死的敏感性为66.7%(2/3),特异性为87.5%(7/8),准确性为81.8%(9/11),阳性预测值为66.7%(2/3),阴性预测值为87.5%(7/8)。术前探测穿支血管16支,术中证实13支;探测10支血管链,术中证实10支血管链。结论:连接智能手机的红外热成像技术在术前探查血管穿支、血管链用于辅助皮瓣设计,术中术后监测皮瓣的皮温、血运以预测、预防皮瓣的坏死方面具有较高的客观性及有效性,可客观有效地辅助外科医生设计皮瓣、评估皮瓣血运,值得临床推广应用。
基金supported by the National Natural Science Foundation of China (No.U21B2071).
文摘Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress interference,which results in uneven fracture propagation. It is common practice to use “balls” to temporarily plug fractureopenings in order to lessen liquid intake and achieve uniform propagation in each cluster. In this study, a diameteroptimization model is introduced for these plugging balls based on a multi-cluster fracture propagationmodel and a perforation dynamic abrasion model. This approach relies on proper consideration of the multiphasenature of the considered problem and the interaction force between the involved fluid and solid phases. Accordingly,it can take into account the behavior of the gradually changing hole diameter due to proppant continuousperforation erosion. Moreover, it can provide useful information about the fluid-dynamic behavior of the consideredsystem before and after plugging. It is shown that when the diameter of the temporary plugging ball is1.2 times that of the perforation hole, the perforation holes of each cluster can be effectively blocked.
