目的研究动态增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)定量参数分析在早期乳腺癌诊断中的应用价值。方法选取浙江省台州医院2020年6月至2021年6月收治的乳腺癌患者70例为恶性组,另选取同期浙江...目的研究动态增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)定量参数分析在早期乳腺癌诊断中的应用价值。方法选取浙江省台州医院2020年6月至2021年6月收治的乳腺癌患者70例为恶性组,另选取同期浙江省台州医院收治的乳腺纤维腺瘤患者30例为良性组,采用DCE-MRI定量参数对乳腺癌和乳腺纤维腺瘤进行鉴别诊断分析,比较两组的DCE-MRI定量参数容量转移常数(volume transfer constant,K^(trans))、反流速率常数(reflux rate constant,K_(ep))、血管外细胞外间隙容积比(volume of the external vascular extracellular space,V_(e)),比较不同病理类型DCE-MRI定量参数K^(trans)、K_(ep)、V_(e)及DCE-MRI定量参数分析与乳腺癌患者预后的相关性及诊断敏感度、准确性。结果良性组的DCE-MRI定量参数K^(trans)、K_(ep)、V_(e)均低于恶性组(P<0.0001);导管内癌组的K^(trans)、K_(ep)、V_(e)及非特殊类型浸润性癌的K^(trans)、K_(ep)、V_(e)均低于特殊类型癌(P<0.05);雌激素受体(estrogen receptor,ER)表达阴性组的K_(ep)高于ER阳性组(P<0.05);孕激素受体(progesterone receptor,PR)阴性组的K_(ep)高于PR阳性组(P<0.05);ER、PR阴性组的K^(trans)、V_(e)高于ER、PR阳性组;人类表皮生长因子受体-2低表达和过表达组的K^(trans)、K_(ep)、V_(e)比较,差异无统计学意义(P>0.05);与K^(trans)、K_(ep)、V_(e)单一诊断比较,联合诊断对乳腺癌诊断价值较高(P<0.05)。结论DCE-MRI定量参数分析用于早期乳腺癌的诊断,能有效鉴别不同疾病的类型及预后,诊断价值较高。展开更多
In order to analyze and simulate the complex super-plastic forming process by computer, a method of equal height bulging for determining material parameters m and K of the superplastic alloy is presented. The formulae...In order to analyze and simulate the complex super-plastic forming process by computer, a method of equal height bulging for determining material parameters m and K of the superplastic alloy is presented. The formulae related to the method are deduced in this paper. The accuracy of the method is available for evaluating the examples used in simulating the superplastic sheet-metal bulging processes.展开更多
Conical membrane structures are a typical form of tensile membrane structures. In the past, most studies focused on the static performance, but few on dynamic performance. In this paper, systematic parameter analysis ...Conical membrane structures are a typical form of tensile membrane structures. In the past, most studies focused on the static performance, but few on dynamic performance. In this paper, systematic parameter analysis of wind-induced response of conical membrane structures has been performed with nonlinear random simulation method in a time domain, by considering some parameters, such as span, rise-span ratio, prestress of membrane, and characteristic of the approaching wind flow. Moreover, formulas of the dynamic coefficient and nonlinear adjustment factor are advised, which can be conveniently used in wind-resistant design of conical membrane structures.展开更多
In this paper, the method of vibration measurement and modal analysis for AM50 Tunneller machine is presented. When the machine was used for cutting man made coal bed and real coal bed, the vibration of the machine wa...In this paper, the method of vibration measurement and modal analysis for AM50 Tunneller machine is presented. When the machine was used for cutting man made coal bed and real coal bed, the vibration of the machine was measured and the results of signal analysis show that the vibration characteristics under the two kinds of working situations are similar. The modal model of the machine is established, and then, the intrinsic vibration characteristics of AM50 tunneller are investigated by means of the method of experimental modal analysis. The vibration response simulation under a set of loading spectra measured is carried out by force response simulation software.展开更多
This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k...This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.展开更多
An ultra-accurate isogeometric dynamic analysis is presented.The key ingredient of the proposed methodology is the development of isogeometric higher order mass matrix.A new one-step method is proposed for the constru...An ultra-accurate isogeometric dynamic analysis is presented.The key ingredient of the proposed methodology is the development of isogeometric higher order mass matrix.A new one-step method is proposed for the construction of higher order mass matrix.In this approach,an adjustable mass matrix is formulated through introducing a set of mass parameters into the consistent mass matrix under the element mass conservation condition.Then the semi-discrete frequency derived from the free vibration equation with the adjustable mass matrix is served as a measure to optimize the mass parameters.In 1D analysis,it turns out that the present one-step method can perfectly recover the existing reduced bandwidth mass matrix and the higher order mass matrix by choosing different mass parameters.However,the employment of the proposed one-step method to the2D membrane problem yields a remarkable gain of solution accuracy compared with the higher order mass matrix generated by the original two-step method.Subsequently a full-discrete isogeometric transient analysis algorithm is presented by using the Newmark time integration scheme and the higher order mass matrix.The full-discrete frequency is derived to assess the accuracy of space-time discretization.Finally a set of numerical examples are presented to evaluate the accuracy of the proposed method,which show that very favorable solution accuracy is achieved by the present dynamic isogeometric analysis with higher order mass formulation compared with that obtained from the standard consistent mass approach.展开更多
文摘目的研究动态增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)定量参数分析在早期乳腺癌诊断中的应用价值。方法选取浙江省台州医院2020年6月至2021年6月收治的乳腺癌患者70例为恶性组,另选取同期浙江省台州医院收治的乳腺纤维腺瘤患者30例为良性组,采用DCE-MRI定量参数对乳腺癌和乳腺纤维腺瘤进行鉴别诊断分析,比较两组的DCE-MRI定量参数容量转移常数(volume transfer constant,K^(trans))、反流速率常数(reflux rate constant,K_(ep))、血管外细胞外间隙容积比(volume of the external vascular extracellular space,V_(e)),比较不同病理类型DCE-MRI定量参数K^(trans)、K_(ep)、V_(e)及DCE-MRI定量参数分析与乳腺癌患者预后的相关性及诊断敏感度、准确性。结果良性组的DCE-MRI定量参数K^(trans)、K_(ep)、V_(e)均低于恶性组(P<0.0001);导管内癌组的K^(trans)、K_(ep)、V_(e)及非特殊类型浸润性癌的K^(trans)、K_(ep)、V_(e)均低于特殊类型癌(P<0.05);雌激素受体(estrogen receptor,ER)表达阴性组的K_(ep)高于ER阳性组(P<0.05);孕激素受体(progesterone receptor,PR)阴性组的K_(ep)高于PR阳性组(P<0.05);ER、PR阴性组的K^(trans)、V_(e)高于ER、PR阳性组;人类表皮生长因子受体-2低表达和过表达组的K^(trans)、K_(ep)、V_(e)比较,差异无统计学意义(P>0.05);与K^(trans)、K_(ep)、V_(e)单一诊断比较,联合诊断对乳腺癌诊断价值较高(P<0.05)。结论DCE-MRI定量参数分析用于早期乳腺癌的诊断,能有效鉴别不同疾病的类型及预后,诊断价值较高。
文摘In order to analyze and simulate the complex super-plastic forming process by computer, a method of equal height bulging for determining material parameters m and K of the superplastic alloy is presented. The formulae related to the method are deduced in this paper. The accuracy of the method is available for evaluating the examples used in simulating the superplastic sheet-metal bulging processes.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50338010).
文摘Conical membrane structures are a typical form of tensile membrane structures. In the past, most studies focused on the static performance, but few on dynamic performance. In this paper, systematic parameter analysis of wind-induced response of conical membrane structures has been performed with nonlinear random simulation method in a time domain, by considering some parameters, such as span, rise-span ratio, prestress of membrane, and characteristic of the approaching wind flow. Moreover, formulas of the dynamic coefficient and nonlinear adjustment factor are advised, which can be conveniently used in wind-resistant design of conical membrane structures.
文摘In this paper, the method of vibration measurement and modal analysis for AM50 Tunneller machine is presented. When the machine was used for cutting man made coal bed and real coal bed, the vibration of the machine was measured and the results of signal analysis show that the vibration characteristics under the two kinds of working situations are similar. The modal model of the machine is established, and then, the intrinsic vibration characteristics of AM50 tunneller are investigated by means of the method of experimental modal analysis. The vibration response simulation under a set of loading spectra measured is carried out by force response simulation software.
文摘This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.
基金supported by the National Natural Science Foundation of China(Grant No.11222221)
文摘An ultra-accurate isogeometric dynamic analysis is presented.The key ingredient of the proposed methodology is the development of isogeometric higher order mass matrix.A new one-step method is proposed for the construction of higher order mass matrix.In this approach,an adjustable mass matrix is formulated through introducing a set of mass parameters into the consistent mass matrix under the element mass conservation condition.Then the semi-discrete frequency derived from the free vibration equation with the adjustable mass matrix is served as a measure to optimize the mass parameters.In 1D analysis,it turns out that the present one-step method can perfectly recover the existing reduced bandwidth mass matrix and the higher order mass matrix by choosing different mass parameters.However,the employment of the proposed one-step method to the2D membrane problem yields a remarkable gain of solution accuracy compared with the higher order mass matrix generated by the original two-step method.Subsequently a full-discrete isogeometric transient analysis algorithm is presented by using the Newmark time integration scheme and the higher order mass matrix.The full-discrete frequency is derived to assess the accuracy of space-time discretization.Finally a set of numerical examples are presented to evaluate the accuracy of the proposed method,which show that very favorable solution accuracy is achieved by the present dynamic isogeometric analysis with higher order mass formulation compared with that obtained from the standard consistent mass approach.
