目的:本研究主要是对普通动力髋螺钉(Dynamic hip screw-DHS)的头颈拉力螺钉进行改进,设计一种新型拉力螺钉,其主要特点是前端螺纹部分可以扩张,然后进行生物力学测试,了解其各项性能参数,并与普通DHS进行比较。方法:将具有可扩张翼型...目的:本研究主要是对普通动力髋螺钉(Dynamic hip screw-DHS)的头颈拉力螺钉进行改进,设计一种新型拉力螺钉,其主要特点是前端螺纹部分可以扩张,然后进行生物力学测试,了解其各项性能参数,并与普通DHS进行比较。方法:将具有可扩张翼型拉力螺钉的动力髋螺钉固定(实验组A1、B1、C1),普通动力髋螺钉(对照组A2、B2、C2)在生物力学实验机上进行抗轴向压缩试验、抗扭转试验以及抗拔出试验。结果:在轴向压缩实验结果:t=6.067,P=0.02<0.05。扭转实验中,t=2.792,P=0.038<0.05。在最大轴向拔出力实验中,t=7.798,P=0.01<0.05。结论:具有可扩张翼型拉力螺钉的动力髋螺钉固定的转子间骨折模型,在抗轴向压力、抗扭转以及抗拔出三个方面均较普通DHS固定的转子间骨折模型有明显优势。展开更多
Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied ...Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban expansion.The research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was faster.And 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical expansion.Those two driving forces were simultaneously affected by city's political factors.展开更多
Photodynamic therapy (PDT) is an established endoscopic technique for ablating Barrett's esophagus with high-grade dysplasia or early-stage intraepithelial neoplasia. The most common clinically significant adverse...Photodynamic therapy (PDT) is an established endoscopic technique for ablating Barrett's esophagus with high-grade dysplasia or early-stage intraepithelial neoplasia. The most common clinically significant adverse effect of PDT is esophageal stricture formation. The strictures are usually superficial and might be dilated effectively with standard endoscopic accessories, such as endoscope balloon or Savary dilators. However, multiple dilations might be required to achieve stricture resolution in some cases. We report the case of stricture that recurred after dilation with a bougie, which was completely relieved by a self-expandable metal stent.展开更多
The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-...The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-domain CFD approach and the frequency-domain finite element method(FEM) agree well with each other for the dual expansion chamber silencer, straight-through and cross-flow perforated tube silencers without flow. Then, the time-domain CFD approach is used to investigate the effect of flow on the acoustic attenuation characteristics of perforated tube silencers. The numerical predictions demonstrate that the mean flow increases the transmission loss, especially at higher frequencies, and shifts the transmission loss curve to lower frequencies.展开更多
For the diffusion-controlled adsorption, the expression of dynamic surface adsorption P（t） was ob- tained by solving the diffusion equation. Two cases, i.e. the short and long time limits, were mainly discussed in t...For the diffusion-controlled adsorption, the expression of dynamic surface adsorption P（t） was ob- tained by solving the diffusion equation. Two cases, i.e. the short and long time limits, were mainly discussed in this paper. From the measured dynamic surface tension of aqueous surfactant sodium dodecyl sulfate （SDS） solutions at 25 ℃, the adsorption kinetics of SDS at air/solution interface was studied. It was proved that for both of the short and long time limits, the adsorption process of SDS was controlled by diffusion.展开更多
The two-dimensional barrier passage is studied in the framework of Langevin statistical reactive dynamics.The optimal incident angle for a particle diffusing in the dissipative non-orthogonal environment with various ...The two-dimensional barrier passage is studied in the framework of Langevin statistical reactive dynamics.The optimal incident angle for a particle diffusing in the dissipative non-orthogonal environment with various strengthsof coupling between the two degrees of freedom is systematically calculated.The optimal diffusion path of the particlein a non-Ohmic damping system is revealed to have a probability to return to the potential valley under the combinedinfluence of the off-diagonal system tensors.展开更多
文摘目的:本研究主要是对普通动力髋螺钉(Dynamic hip screw-DHS)的头颈拉力螺钉进行改进,设计一种新型拉力螺钉,其主要特点是前端螺纹部分可以扩张,然后进行生物力学测试,了解其各项性能参数,并与普通DHS进行比较。方法:将具有可扩张翼型拉力螺钉的动力髋螺钉固定(实验组A1、B1、C1),普通动力髋螺钉(对照组A2、B2、C2)在生物力学实验机上进行抗轴向压缩试验、抗扭转试验以及抗拔出试验。结果:在轴向压缩实验结果:t=6.067,P=0.02<0.05。扭转实验中,t=2.792,P=0.038<0.05。在最大轴向拔出力实验中,t=7.798,P=0.01<0.05。结论:具有可扩张翼型拉力螺钉的动力髋螺钉固定的转子间骨折模型,在抗轴向压力、抗扭转以及抗拔出三个方面均较普通DHS固定的转子间骨折模型有明显优势。
基金Under the auspices of the Key Direction in Knowledge Innovation Programs of Chinese Academy of Sciences (No KZCX2-YW-422)National Natural Science Foundation of China (No 40701059)
文摘Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban expansion.The research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was faster.And 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical expansion.Those two driving forces were simultaneously affected by city's political factors.
文摘Photodynamic therapy (PDT) is an established endoscopic technique for ablating Barrett's esophagus with high-grade dysplasia or early-stage intraepithelial neoplasia. The most common clinically significant adverse effect of PDT is esophageal stricture formation. The strictures are usually superficial and might be dilated effectively with standard endoscopic accessories, such as endoscope balloon or Savary dilators. However, multiple dilations might be required to achieve stricture resolution in some cases. We report the case of stricture that recurred after dilation with a bougie, which was completely relieved by a self-expandable metal stent.
基金Project(11174065)supported by the National Natural Science Foundation of China
文摘The multi-dimensional time-domain computational fluid dynamics(CFD) approach is extended to calculate the acoustic attenuation performance of water-filled piping silencers. Transmission loss predictions from the time-domain CFD approach and the frequency-domain finite element method(FEM) agree well with each other for the dual expansion chamber silencer, straight-through and cross-flow perforated tube silencers without flow. Then, the time-domain CFD approach is used to investigate the effect of flow on the acoustic attenuation characteristics of perforated tube silencers. The numerical predictions demonstrate that the mean flow increases the transmission loss, especially at higher frequencies, and shifts the transmission loss curve to lower frequencies.
文摘For the diffusion-controlled adsorption, the expression of dynamic surface adsorption P（t） was ob- tained by solving the diffusion equation. Two cases, i.e. the short and long time limits, were mainly discussed in this paper. From the measured dynamic surface tension of aqueous surfactant sodium dodecyl sulfate （SDS） solutions at 25 ℃, the adsorption kinetics of SDS at air/solution interface was studied. It was proved that for both of the short and long time limits, the adsorption process of SDS was controlled by diffusion.
基金Supported by the Scientific Research Starting Foundation of Qufu Normal University and the National Natural Science Foundation of China under Grant No.10847101
文摘The two-dimensional barrier passage is studied in the framework of Langevin statistical reactive dynamics.The optimal incident angle for a particle diffusing in the dissipative non-orthogonal environment with various strengthsof coupling between the two degrees of freedom is systematically calculated.The optimal diffusion path of the particlein a non-Ohmic damping system is revealed to have a probability to return to the potential valley under the combinedinfluence of the off-diagonal system tensors.
