Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ...Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.Methods: Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals,intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.Results: MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations(P > 0.05).Conclusion: CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation.展开更多
This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dyna...This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details.展开更多
本文针对平面内弯矩作用下的T形圆管相贯节点焊缝处热点应力分布开展研究.利用径向拉伸法建立了T形圆管相贯节点的有限元网格模型,对热点应力分析结果的可靠性进行了网格密度分析和试验对比分析,提出了满足计算精度要求的基本密度网格....本文针对平面内弯矩作用下的T形圆管相贯节点焊缝处热点应力分布开展研究.利用径向拉伸法建立了T形圆管相贯节点的有限元网格模型,对热点应力分析结果的可靠性进行了网格密度分析和试验对比分析,提出了满足计算精度要求的基本密度网格.通过无量纲几何参数分析归纳了热点应力沿相贯线的环向分布规律及几何参数影响规律,发现了冠点波峰分裂现象及分裂过程中波峰曲线的三种变化形态,在此基础上提出了采用以π为周期的系数来修正冠点曲线形状的波形修正方法及分布曲线参数公式.与伦敦大学学院(University College London,UCL)两位学者的公式和试验数据进行对比分析,结果表明本文公式具有更简洁的表达形式和更高的精度.展开更多
文摘Aim: To assess the quality of high-resolution CT section planes(HRCT), multi-planar reformation(MPR) and 3-dimensional volume rendered computer tomography(3D-CTVR) were here used in the fine differential diagnosis of ossicular chain in the case of conductive hearing loss with intact tympanic membrane.Methods: Here, 17 cases of otosclerosis and 22 cases of ossicular chain deformity were selected. All patients had normal external ear canals,intact tympanic membranes, conductive hearing loss, type A tympanograms, and negative Gelle's tests. The respective radiological reports of the status of the ossicles via 3 protocols were compared to surgical findings. The quantitative assessments of the representation of different segments of the ossicular chain were based on a 3-point scoring system.Results: MPR and CTVR imaging both showed the integrity of whole ossicular chain well. MPR and CTVR imaging were found to be superior to section planes with respect to showing the superstructure of the stapes and malformations(P > 0.05).Conclusion: CTVR and MPR imaging were found to be better able to show the whole ossicular chain in the conductive hearing loss with normal tympanic membranes. Furthermore, the use of these techniques can have profound contributive value in the differential diagnosis of otosclerosis and ossicular chain absence or malformation.
基金Project supported by the Natural Science Foundation of Shanxi Province,China (Grant No 20051008)the Science Foundation for Returnee of Shanxi Province of China (Grant No 02-16)
文摘This paper presents the fully differential cross sections （FDCS） for 102eV electron impact single ionization of helium for both the coplanar and perpendicular plane asymmetric geometries within the framework of dynamically screened three-Coulomb-wave theory. Comparisons are made with the experimental data and those of the three-Coulomb wave function model and second-order distorted-wave Born method. The angular distribution and relative heights of the present FDCS is found to be in very good agreement with the experimental data in the perpendicular plane geometry. It is shown that dynamical screening effects are significant in this geometry. Three-body coupling is expected to be weak in the coplanar geometry, although the precise absolute value of the cross section is still sensitive to the interaction details.
文摘本文针对平面内弯矩作用下的T形圆管相贯节点焊缝处热点应力分布开展研究.利用径向拉伸法建立了T形圆管相贯节点的有限元网格模型,对热点应力分析结果的可靠性进行了网格密度分析和试验对比分析,提出了满足计算精度要求的基本密度网格.通过无量纲几何参数分析归纳了热点应力沿相贯线的环向分布规律及几何参数影响规律,发现了冠点波峰分裂现象及分裂过程中波峰曲线的三种变化形态,在此基础上提出了采用以π为周期的系数来修正冠点曲线形状的波形修正方法及分布曲线参数公式.与伦敦大学学院(University College London,UCL)两位学者的公式和试验数据进行对比分析,结果表明本文公式具有更简洁的表达形式和更高的精度.
