By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the gener...By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the general sixdegrees-of-freedom plate theory towards the accurate stress analysis. The solutions of interlaminar stress and nonlinear dynamic response for a simply supported laminated plate with interfacial damage are obtained by using the finite difference method, and the results are validated by comparison with the solution of nonlinear finite element method. In numerical calculations, the effects of interfacial damage on the stress in the interface and the nonlinear dynamic response of laminated plates are discussed.展开更多
Based on the general six-degrees-of-freedom plate theory towards the accurate stress analysis and nonlinear theory of shallow shells, considering the damage effect of the interlaminar in- terface and using the variati...Based on the general six-degrees-of-freedom plate theory towards the accurate stress analysis and nonlinear theory of shallow shells, considering the damage effect of the interlaminar in- terface and using the variation principle, the three-dimensional non-linear equilibrium differential equations of the laminated shallow shells with interfacial damage are derived. Then, considering a simply supported laminated shallow shell with damage and under normal load, an analytical solution is presented by using finite difference method to obtain the interlaminar stresses. Numer- ical results show, the stiffness of the shell is weakened, greater absolute values of displacements as well as smaller interlaminar stresses are obtained by interfacial damage. When the interfacial damage is further increased, delamination occurs obviously under normal pulling load and pure shear slip occurs under normal pressure load. The portion of the load undertaken by the two sides of the interface is more different. Different mechanical behaviors are shown in both sides of the interface, and the discontinuation of stresses and displacements takes place in the interface.展开更多
The reliability of radiotherapy was evaluated and effective approaches were obtained in order to improve radiotherapy quality by using the Probabilistic Safety Assessment(PSA) method. This study investigated the feasi...The reliability of radiotherapy was evaluated and effective approaches were obtained in order to improve radiotherapy quality by using the Probabilistic Safety Assessment(PSA) method. This study investigated the feasibility of the PSA method being applied to radiotherapy through Image-guided Radiotherapy(IGRT) and chest tumor irradiation. A fault tree has been constructed after analyzing causal relationship of the events.After calculating Risk A, a total inaccuracy radiotherapy probability and the importance of all base events were obtained. The probability of inaccurate radiotherapy was 2.87%. Under the condition that the target delineation was perfectly right, the accuracy of radiotherapy significantly improved. With the calculation without Conebeam Computed Tomography(CBCT) being corrected before irradiation, the accuracy significantly decreased.The most important events were connected with the human factor. Improving human technical level could enhance radiotherapy quality control efficiently.展开更多
This investigation aimed at improving the performance of Taylor’s dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carri...This investigation aimed at improving the performance of Taylor’s dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carried out on a capillary electrophoresis instrument by monitoring the UV absorption peak of a solute pulse and calculating the diffusion coefficient by peak efficiency. With L-phenylalanine as a main testing solute, some key factors were afterward disclosed including especially the capillary size, carrier flow velocity, injection volume and capillary conditioning. Peak tailing, large volume of sample injection and slow migration were found to underestimate the diffusion coefficient while very fast migration and high sample concentration caused overestimation. At a moderate flow velocity of 0.1―1 cm/s with a capillary of 72.44 μm I.D.×60 cm (50 cm effective) maintained at 25℃, the diffusion coefficient of aqueous L-phenylalanine was determined, giving a value of 7.02×10-6 cm2/s with error <2% and relative standard deviation <0.2% (n=3). The method was shown to be applicable to the measurement of various samples such as aqueous phenylalanine, acetone, phenol, toluene and benzene, and nonaqueous benzene (in ethanol or 1-butanol).展开更多
随着信息化进程的加快,管理信息系统(Management Information System,MIS)已成为企事业单位资源管理与决策支持的重要工具。用户在系统中的操作行为不断积累,形成了丰富的数据资源。如何通过对用户行为数据的分析,挖掘潜在规律,并据此...随着信息化进程的加快,管理信息系统(Management Information System,MIS)已成为企事业单位资源管理与决策支持的重要工具。用户在系统中的操作行为不断积累,形成了丰富的数据资源。如何通过对用户行为数据的分析,挖掘潜在规律,并据此实现个性化、精准化服务,成为提升系统效能和用户体验的关键问题。文章基于大数据分析与机器学习方法,对管理信息系统中用户行为数据的采集、清洗、建模与分析进行研究,提出了一套面向精准服务的策略框架。研究结果表明,用户行为数据能精准映射其需求与偏好,结合聚类分析、关联规则挖掘与推荐算法,可实现精准的内容推送与服务优化。该研究为管理信息系统的智能化发展提供了理论参考与实践路径。展开更多
基金the National Natural Science Foundation of China (10572049)Hunan Provincial Natural Science Foundation of China (07JJ3009)National 985 Special Foundation of China
文摘By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the general sixdegrees-of-freedom plate theory towards the accurate stress analysis. The solutions of interlaminar stress and nonlinear dynamic response for a simply supported laminated plate with interfacial damage are obtained by using the finite difference method, and the results are validated by comparison with the solution of nonlinear finite element method. In numerical calculations, the effects of interfacial damage on the stress in the interface and the nonlinear dynamic response of laminated plates are discussed.
基金supported by the National Natural Science Foundation of China (No. 11072076)
文摘Based on the general six-degrees-of-freedom plate theory towards the accurate stress analysis and nonlinear theory of shallow shells, considering the damage effect of the interlaminar in- terface and using the variation principle, the three-dimensional non-linear equilibrium differential equations of the laminated shallow shells with interfacial damage are derived. Then, considering a simply supported laminated shallow shell with damage and under normal load, an analytical solution is presented by using finite difference method to obtain the interlaminar stresses. Numer- ical results show, the stiffness of the shell is weakened, greater absolute values of displacements as well as smaller interlaminar stresses are obtained by interfacial damage. When the interfacial damage is further increased, delamination occurs obviously under normal pulling load and pure shear slip occurs under normal pressure load. The portion of the load undertaken by the two sides of the interface is more different. Different mechanical behaviors are shown in both sides of the interface, and the discontinuation of stresses and displacements takes place in the interface.
基金Supported by the National Natural Science Foundation of China(No.81101132)the Natural Science Foundation of Anhui Province(No.11040606Q55)
文摘The reliability of radiotherapy was evaluated and effective approaches were obtained in order to improve radiotherapy quality by using the Probabilistic Safety Assessment(PSA) method. This study investigated the feasibility of the PSA method being applied to radiotherapy through Image-guided Radiotherapy(IGRT) and chest tumor irradiation. A fault tree has been constructed after analyzing causal relationship of the events.After calculating Risk A, a total inaccuracy radiotherapy probability and the importance of all base events were obtained. The probability of inaccurate radiotherapy was 2.87%. Under the condition that the target delineation was perfectly right, the accuracy of radiotherapy significantly improved. With the calculation without Conebeam Computed Tomography(CBCT) being corrected before irradiation, the accuracy significantly decreased.The most important events were connected with the human factor. Improving human technical level could enhance radiotherapy quality control efficiently.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20435030 and 20628507)Chinese Academy of Sciences and the Ministry of Science and Technology (Grant No. 2002CB713803)
文摘This investigation aimed at improving the performance of Taylor’s dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carried out on a capillary electrophoresis instrument by monitoring the UV absorption peak of a solute pulse and calculating the diffusion coefficient by peak efficiency. With L-phenylalanine as a main testing solute, some key factors were afterward disclosed including especially the capillary size, carrier flow velocity, injection volume and capillary conditioning. Peak tailing, large volume of sample injection and slow migration were found to underestimate the diffusion coefficient while very fast migration and high sample concentration caused overestimation. At a moderate flow velocity of 0.1―1 cm/s with a capillary of 72.44 μm I.D.×60 cm (50 cm effective) maintained at 25℃, the diffusion coefficient of aqueous L-phenylalanine was determined, giving a value of 7.02×10-6 cm2/s with error <2% and relative standard deviation <0.2% (n=3). The method was shown to be applicable to the measurement of various samples such as aqueous phenylalanine, acetone, phenol, toluene and benzene, and nonaqueous benzene (in ethanol or 1-butanol).
文摘随着信息化进程的加快,管理信息系统(Management Information System,MIS)已成为企事业单位资源管理与决策支持的重要工具。用户在系统中的操作行为不断积累,形成了丰富的数据资源。如何通过对用户行为数据的分析,挖掘潜在规律,并据此实现个性化、精准化服务,成为提升系统效能和用户体验的关键问题。文章基于大数据分析与机器学习方法,对管理信息系统中用户行为数据的采集、清洗、建模与分析进行研究,提出了一套面向精准服务的策略框架。研究结果表明,用户行为数据能精准映射其需求与偏好,结合聚类分析、关联规则挖掘与推荐算法,可实现精准的内容推送与服务优化。该研究为管理信息系统的智能化发展提供了理论参考与实践路径。
