目的:了解负压吸引拉力式弹力线套扎器在治疗脱垂痔病中的治疗效果,建立新的套扎术在治疗脱垂性痔病的治疗体系。方法:采用回顾性分析方法,选择2016年1月—2018年6月我院诊断为脱垂Ⅱ、Ⅲ及Ⅳ型脱垂性痔病患者,采取新型负压吸引拉力式...目的:了解负压吸引拉力式弹力线套扎器在治疗脱垂痔病中的治疗效果,建立新的套扎术在治疗脱垂性痔病的治疗体系。方法:采用回顾性分析方法,选择2016年1月—2018年6月我院诊断为脱垂Ⅱ、Ⅲ及Ⅳ型脱垂性痔病患者,采取新型负压吸引拉力式弹力线套扎器治疗。定期随访、收集术后设定各种数据,综合分析。结果:手术后住院时间最短4 d、最长21 d,平均8.7 d。疼痛评分:术后0~1 d无痛40例、2~3分242例、4~6分21例;术后2~3 d 2~3分189例;术后4~6 d 4~6分10例;术后9 d 4~6分2例。术后并发症:活动性出血5例、直肠狭窄5例、肛门狭窄0例、肛门增生肉芽78例、切口平均愈合时间(40.0±7.2)d。结论:弹力线套扎术能明显提升和固定脱垂性肛垫,合理缩减病理性肛垫。术中组织损伤小,出血少,术后并发症发生率较低,恢复工作时间快。与传统手术相比,能最大程度地保护肛门直肠组织结构,所有病例术后均达到治愈标准。展开更多
We propose an Ashkin-Teller-like model for elastic response of DNA molecule to external force and torque. The base-stacking interaction is described in a simple and uniform way. We obtain the phase diagram of dsDNA, a...We propose an Ashkin-Teller-like model for elastic response of DNA molecule to external force and torque. The base-stacking interaction is described in a simple and uniform way. We obtain the phase diagram of dsDNA, and in particular, the transition from 13 form to the S state induced by stretching and twisting. The elastic response of the ssDNA is presented also in a unified formalism. The close relation of dsDNA molecule structure with elastic response is shown clearly. The calculated folding angle of the dsDNA molecule is 59.2°.展开更多
To investigate the ballistic resistance and failure pattern of aeroengine casing following the impact of disk fragments, and to determine the optimum case structure, the phenomena of a 1/3rd disk fragment impact on si...To investigate the ballistic resistance and failure pattern of aeroengine casing following the impact of disk fragments, and to determine the optimum case structure, the phenomena of a 1/3rd disk fragment impact on single and double-layered thin plate targets were simulated using nonlinear dynamical analysis software MSC.Dytran. Strain rate effect was introduced in a Johnson-Cook (JC) material model for the disk fragment and the plate. Impact modeling was based on the Arbitrary Lagrange-Eulerian method, and simulated using explicit finite element method (FEM). Simulation results showed that the major failure pattern of the plate is shearing and tensile fracture with large plastic deformation. It was also concluded that the ballistic limit velocity increases with the standoff distance when it is beyond a certain value, and that greater resistance is obtained when the front plate has either a proportionately low or high thickness. The impact resistance of a double-layered plate may exceed that of a single plate if the thicknesses and standoff distance of the two plates are set appropriately.展开更多
This paper presents a summary of various localized collocation schemes and their engineering applications.The basic concepts of localized collocation methods(LCMs)are first introduced,such as approximation theory,semi...This paper presents a summary of various localized collocation schemes and their engineering applications.The basic concepts of localized collocation methods(LCMs)are first introduced,such as approximation theory,semianalytical collocation methods and localization strategies.Based on these basic concepts,five different formulations of localized collocation methods are introduced,including the localized radial basis function collocation method(LRBFCM)and the generalized finite difference method(GFDM),the localized method of fundamental solutions(LMFS),the localized radial Trefftz collocation method(LRTCM),and the localized collocation Trefftz method(LCTM).Then,several additional schemes,such as the generalized reciprocity method,Laplace and Fourier transformations,and Krylov deferred correction,are introduced to enable the application of the LCM to large-scale engineering and scientific computing for solving inhomogeneous,nonisotropic and time-dependent partial differential equations.Several typical benchmark examples are presented to show the recent developments and applications on the LCM solution of some selected boundary value problems,such as numerical wave flume,potential-based inverse electrocardiography,wave propagation analysis and 2D phononic crystals,elasticity and in-plane crack problems,heat conduction problems in heterogeneous material and nonlinear time-dependent Burgers’equations.Finally,some conclusions and outlooks of the LCMs are summarized.展开更多
The authors consider the Euler equations for a compressible fluid in one space dimensionwhen the equation of state of the fluid does not fulfill standard convexity assumptions andviscosity and capillarity effects are ...The authors consider the Euler equations for a compressible fluid in one space dimensionwhen the equation of state of the fluid does not fulfill standard convexity assumptions andviscosity and capillarity effects are taken into account. A typical example of nonconvex con-stitutive equation for fluids is Van der Waals' equation. The first order terms of these partialdifferential equations form a nonlinear system of mixed (hyperbolic-elliptic) type. For a class ofnonconvex equations of state, an existence theorem of traveling waves solutions with arbitrarylarge amplitude is established here. The authors distinguish between classical (compressive) andnonclassical (undercompressive) traveling waves. The latter do not fulfill Lax shock inequali-ties, and are characterized by the so-called kinetic relation, whose properties are investigatedin this paper.展开更多
文摘目的:了解负压吸引拉力式弹力线套扎器在治疗脱垂痔病中的治疗效果,建立新的套扎术在治疗脱垂性痔病的治疗体系。方法:采用回顾性分析方法,选择2016年1月—2018年6月我院诊断为脱垂Ⅱ、Ⅲ及Ⅳ型脱垂性痔病患者,采取新型负压吸引拉力式弹力线套扎器治疗。定期随访、收集术后设定各种数据,综合分析。结果:手术后住院时间最短4 d、最长21 d,平均8.7 d。疼痛评分:术后0~1 d无痛40例、2~3分242例、4~6分21例;术后2~3 d 2~3分189例;术后4~6 d 4~6分10例;术后9 d 4~6分2例。术后并发症:活动性出血5例、直肠狭窄5例、肛门狭窄0例、肛门增生肉芽78例、切口平均愈合时间(40.0±7.2)d。结论:弹力线套扎术能明显提升和固定脱垂性肛垫,合理缩减病理性肛垫。术中组织损伤小,出血少,术后并发症发生率较低,恢复工作时间快。与传统手术相比,能最大程度地保护肛门直肠组织结构,所有病例术后均达到治愈标准。
基金National Natural Science Foundation of China under Grant Nos.10575106 and 10375072
文摘We propose an Ashkin-Teller-like model for elastic response of DNA molecule to external force and torque. The base-stacking interaction is described in a simple and uniform way. We obtain the phase diagram of dsDNA, and in particular, the transition from 13 form to the S state induced by stretching and twisting. The elastic response of the ssDNA is presented also in a unified formalism. The close relation of dsDNA molecule structure with elastic response is shown clearly. The calculated folding angle of the dsDNA molecule is 59.2°.
基金Project (No. 1104-03) supported by the Aviation Propulsion Technology Development Program, China
文摘To investigate the ballistic resistance and failure pattern of aeroengine casing following the impact of disk fragments, and to determine the optimum case structure, the phenomena of a 1/3rd disk fragment impact on single and double-layered thin plate targets were simulated using nonlinear dynamical analysis software MSC.Dytran. Strain rate effect was introduced in a Johnson-Cook (JC) material model for the disk fragment and the plate. Impact modeling was based on the Arbitrary Lagrange-Eulerian method, and simulated using explicit finite element method (FEM). Simulation results showed that the major failure pattern of the plate is shearing and tensile fracture with large plastic deformation. It was also concluded that the ballistic limit velocity increases with the standoff distance when it is beyond a certain value, and that greater resistance is obtained when the front plate has either a proportionately low or high thickness. The impact resistance of a double-layered plate may exceed that of a single plate if the thicknesses and standoff distance of the two plates are set appropriately.
基金supported by the National Natural Science Foundation of China(Grant Nos.12122205 and 11772119)the Six Talent Peaks Project in Jiangsu Province of China(Grant No.2019-KTHY-009).
文摘This paper presents a summary of various localized collocation schemes and their engineering applications.The basic concepts of localized collocation methods(LCMs)are first introduced,such as approximation theory,semianalytical collocation methods and localization strategies.Based on these basic concepts,five different formulations of localized collocation methods are introduced,including the localized radial basis function collocation method(LRBFCM)and the generalized finite difference method(GFDM),the localized method of fundamental solutions(LMFS),the localized radial Trefftz collocation method(LRTCM),and the localized collocation Trefftz method(LCTM).Then,several additional schemes,such as the generalized reciprocity method,Laplace and Fourier transformations,and Krylov deferred correction,are introduced to enable the application of the LCM to large-scale engineering and scientific computing for solving inhomogeneous,nonisotropic and time-dependent partial differential equations.Several typical benchmark examples are presented to show the recent developments and applications on the LCM solution of some selected boundary value problems,such as numerical wave flume,potential-based inverse electrocardiography,wave propagation analysis and 2D phononic crystals,elasticity and in-plane crack problems,heat conduction problems in heterogeneous material and nonlinear time-dependent Burgers’equations.Finally,some conclusions and outlooks of the LCMs are summarized.
文摘The authors consider the Euler equations for a compressible fluid in one space dimensionwhen the equation of state of the fluid does not fulfill standard convexity assumptions andviscosity and capillarity effects are taken into account. A typical example of nonconvex con-stitutive equation for fluids is Van der Waals' equation. The first order terms of these partialdifferential equations form a nonlinear system of mixed (hyperbolic-elliptic) type. For a class ofnonconvex equations of state, an existence theorem of traveling waves solutions with arbitrarylarge amplitude is established here. The authors distinguish between classical (compressive) andnonclassical (undercompressive) traveling waves. The latter do not fulfill Lax shock inequali-ties, and are characterized by the so-called kinetic relation, whose properties are investigatedin this paper.
