In order to promote the reform of vocational education,the state has issued the National Vocational Education Reform Implementation Plan,in which the reform of"Teachers,Teaching Materials,and Teaching Methods&quo...In order to promote the reform of vocational education,the state has issued the National Vocational Education Reform Implementation Plan,in which the reform of"Teachers,Teaching Materials,and Teaching Methods"as well as the"1+X"certificate have been the most prominent topics for discussion.Facing new opportunities for vocational education development,popularizing the blend of"1+x"courses and certificates,strengthening the integration of production and education,as well as enhancing professional soft skills are urgent issues to solved.This article combines the"1+X"certificate of civil engineering professional construction drawings and analyzes the necessity of promoting the"1+X"professional skill level as well as the combination of certificate and curriculum construction in deepening the reform of"Teachers,Teaching Materials,and Teaching Methods."Several suggestions have been put forward for the reform of"Teachers,Teaching Materials,and Teaching Methods"which would be helpful for the practical exploration in the reform of"three teaching methods."展开更多
目的比较腹腔镜下T管缝合时预置缝线法与传统缝合方法的效果差异。方法回顾性分析2020年6月至2023年9月间空军特色医学中心行腹腔镜T管缝合的患者的临床资料,对照组采用传统的T管缝合方法,研究组采用预置缝线的T管缝合方法:间断缝合,进...目的比较腹腔镜下T管缝合时预置缝线法与传统缝合方法的效果差异。方法回顾性分析2020年6月至2023年9月间空军特色医学中心行腹腔镜T管缝合的患者的临床资料,对照组采用传统的T管缝合方法,研究组采用预置缝线的T管缝合方法:间断缝合,进针和出针时前一针的缝线不打紧,每组24例。比较两组患者T管缝合时间和注水试验阳性率。结果研究组术中T管缝合时间少于对照组[(12.61±0.88)min vs(17.62±0.58)min,t=-23.34,P<0.001],注水试验阳性率低于对照组[0 vs 25%(6/24),P=0.029],差异均有统计学意义。结论应用预置缝线的间断缝合法可提高腹腔镜下T管缝合速度,使缝合更确切,较传统方法有明显优势。展开更多
Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be...Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.展开更多
One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudi...One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudinal relaxation time （71） and transverse relaxation time （T2） relative to fluid types in porous media. Based on the 2D NMR relaxation mechanism in a gradient magnetic field, echo train simulation and 2D NMR inversion are discussed in detail. For 2D NMR inversion, a hybrid inversion method is proposed based on the damping least squares method （LSQR） and an improved truncated singular value decomposition （TSVD） algorithm. A series of spin echoes are first simulated with multiple waiting times （Tws） in a gradient magnetic field for given fluid models and these synthesized echo trains are inverted by the hybrid method. The inversion results are consistent with given models. Moreover, the numerical simulation of various fluid models such as the gas-water, light oil-water, and vicious oil-water models were carried out with different echo spacings （TEs） and Tws by this hybrid method. Finally, the influences of different signal-to-noise ratios （SNRs） on inversion results in various fluid models are studied. The numerical simulations show that the hybrid method and optimized observation parameters are applicable to fluid typing of gas-water and oil-water models.展开更多
为了研究阻尼绕组和磁场饱和对汽轮发电机小扰动特性及静态稳定性的影响,分别采用经典派克(Park)方程模型与时步有限元(time-stepping finite element method,T-SFEM)模型,对发电机不同工况下发生的小扰动进行仿真计算。在此基础上,结...为了研究阻尼绕组和磁场饱和对汽轮发电机小扰动特性及静态稳定性的影响,分别采用经典派克(Park)方程模型与时步有限元(time-stepping finite element method,T-SFEM)模型,对发电机不同工况下发生的小扰动进行仿真计算。在此基础上,结合小信号分析法与普罗尼(Prony)方法,对比分析了不同模型下发电机小扰动过程的动态特性以及系统静态稳定性等相关问题。结果表明,在不考虑阻尼绕组与磁场饱和的情况下,2种模型所得的小扰动特性基本一致,而当计及阻尼绕组或磁场饱和作用时则差别显著;采用派克方程模型计算所得的静态稳定极限功角比时步有限元模型的计算结果偏大。研究结果为系统仿真分析提供了合理参考。展开更多
文摘In order to promote the reform of vocational education,the state has issued the National Vocational Education Reform Implementation Plan,in which the reform of"Teachers,Teaching Materials,and Teaching Methods"as well as the"1+X"certificate have been the most prominent topics for discussion.Facing new opportunities for vocational education development,popularizing the blend of"1+x"courses and certificates,strengthening the integration of production and education,as well as enhancing professional soft skills are urgent issues to solved.This article combines the"1+X"certificate of civil engineering professional construction drawings and analyzes the necessity of promoting the"1+X"professional skill level as well as the combination of certificate and curriculum construction in deepening the reform of"Teachers,Teaching Materials,and Teaching Methods."Several suggestions have been put forward for the reform of"Teachers,Teaching Materials,and Teaching Methods"which would be helpful for the practical exploration in the reform of"three teaching methods."
文摘目的比较腹腔镜下T管缝合时预置缝线法与传统缝合方法的效果差异。方法回顾性分析2020年6月至2023年9月间空军特色医学中心行腹腔镜T管缝合的患者的临床资料,对照组采用传统的T管缝合方法,研究组采用预置缝线的T管缝合方法:间断缝合,进针和出针时前一针的缝线不打紧,每组24例。比较两组患者T管缝合时间和注水试验阳性率。结果研究组术中T管缝合时间少于对照组[(12.61±0.88)min vs(17.62±0.58)min,t=-23.34,P<0.001],注水试验阳性率低于对照组[0 vs 25%(6/24),P=0.029],差异均有统计学意义。结论应用预置缝线的间断缝合法可提高腹腔镜下T管缝合速度,使缝合更确切,较传统方法有明显优势。
基金financially supported by the Fourth Term of"333 Engineering"Program of Jiangsu Province(Grant No.BRA2011116)Youth Foundation of Jiangsu Province(Grant No.BK2012095)Special Program for Hadal Science and Technology of Shanghai Ocean University(Grant No.HAST-T-2013-01)
文摘Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.
基金sponsored by the National Natural Science Foundation of China(41172130)the Fundamental Research Funds for the Central Universities(2-9-2012-48)+1 种基金the National Major Projects(No.2011ZX05014-001)CNPC Innovation Foundation(No.2011D-5006-0305)
文摘One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudinal relaxation time （71） and transverse relaxation time （T2） relative to fluid types in porous media. Based on the 2D NMR relaxation mechanism in a gradient magnetic field, echo train simulation and 2D NMR inversion are discussed in detail. For 2D NMR inversion, a hybrid inversion method is proposed based on the damping least squares method （LSQR） and an improved truncated singular value decomposition （TSVD） algorithm. A series of spin echoes are first simulated with multiple waiting times （Tws） in a gradient magnetic field for given fluid models and these synthesized echo trains are inverted by the hybrid method. The inversion results are consistent with given models. Moreover, the numerical simulation of various fluid models such as the gas-water, light oil-water, and vicious oil-water models were carried out with different echo spacings （TEs） and Tws by this hybrid method. Finally, the influences of different signal-to-noise ratios （SNRs） on inversion results in various fluid models are studied. The numerical simulations show that the hybrid method and optimized observation parameters are applicable to fluid typing of gas-water and oil-water models.
文摘为了研究阻尼绕组和磁场饱和对汽轮发电机小扰动特性及静态稳定性的影响,分别采用经典派克(Park)方程模型与时步有限元(time-stepping finite element method,T-SFEM)模型,对发电机不同工况下发生的小扰动进行仿真计算。在此基础上,结合小信号分析法与普罗尼(Prony)方法,对比分析了不同模型下发电机小扰动过程的动态特性以及系统静态稳定性等相关问题。结果表明,在不考虑阻尼绕组与磁场饱和的情况下,2种模型所得的小扰动特性基本一致,而当计及阻尼绕组或磁场饱和作用时则差别显著;采用派克方程模型计算所得的静态稳定极限功角比时步有限元模型的计算结果偏大。研究结果为系统仿真分析提供了合理参考。
