Objective To investigate the therapeutic effect of radial surgery in large cerebral metastatic carcinoma. Methods Adopt three-dimensional oriented radial surgery to 15 patients with the biggest diameter of more than 3...Objective To investigate the therapeutic effect of radial surgery in large cerebral metastatic carcinoma. Methods Adopt three-dimensional oriented radial surgery to 15 patients with the biggest diameter of more than 35mm. Observe the variation of clinical symptoms and analysis the change of CT image. Follow up the survival time, complications and the cause of death at the same time. Results Most of the patients got prominent improvement in symptoms. But the imaging change of carcinoma focus was a slow course comparatively. The survival rate in 1 year was 26%. Conclusion Radial surgery is an effective, simple and safe method in the treatment of large cerebral metastatic carcinoma. It has a good control rate with only slight complications.展开更多
Based on finite volume method, the pressure drop and heat transfer characteristics of one smooth tube and ten different axisymmetric corrugated tubes, including two with uniform corrugation and eight with non-uniform ...Based on finite volume method, the pressure drop and heat transfer characteristics of one smooth tube and ten different axisymmetric corrugated tubes, including two with uniform corrugation and eight with non-uniform corrugation, have been studied. A physical model of the corrugated tube was built, then the numerical simulation of the model was carried out and the numerical simulation results were compared with the empirical formula.The results show that: the friction factor decreases with the increase of Reynolds number ranging from 6000 to 57000, the value of which in the corrugated tubes with non-uniform corrugation(tube 03–10) are smaller than those with uniform corrugation(tube 01–02). The geometry parameters of tube(01) have advantages on the heat transfer enhancement in low Reynolds number flow region(from 6000 to 13000) and tube(07–08)have advantages on the heat transfer enhancement in high Reynolds number flow region(from 13000 to 57000). The vortex, existed in each area between two adjacent corrugations called second flow region, is the root of the enhancement on heat transfer in the corrugated tubes. The effectiveness factor decreases with the increasing of Reynolds number and the performances of the corrugated tubes with pitch of 12.5 mm have advantages than these of 10 mm under the same corrugation geometric parameter.展开更多
Silver nanofluids with three different volume fractions are prepared by a one-step chemical reduction method(Ultra-sound-assisted Membrane Reaction(UAMR)).The convective heat transfer and friction characteristics of s...Silver nanofluids with three different volume fractions are prepared by a one-step chemical reduction method(Ultra-sound-assisted Membrane Reaction(UAMR)).The convective heat transfer and friction characteristics of silver nanofluid in micro-pin fin heat sink are investigated experimentally.The results indicate that the pressure drops of nanofluids with different volume fractions have little difference.Compared to the base fluid(polyvinylpyrrolidone(PVP) solution),the pressure drop of nanofluids increases slightly at the same volume flow rate.When the flow rate is small,the increment is not obvious.The in-troduction of surfactant increases the fluid viscosity,so the pressure drops of nanofluids are larger than those of pure water,under the same flow rate.However,the maximum difference is no more than 10%.The volume fraction of silver nanoparticles significantly affects the convection heat transfer coefficient of micro-pin fin heat sink.The presence of nanoparticles improves significantly the heat transfer performance.However,high viscosity of the nanofluids hinders the heat transfer strengthening effect of nanofluids.In the present work,when the volume fraction of silver particles reaches to 0.012%,the thermal resistance of nanofluid gradually becomes lower than that of deionized water,which indicates the integrated heat transfer enhancement of nanofluids.展开更多
The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method...The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method for engineering problems like membrane separation system.The CFD modeling in this study observes steady and unsteady(transient) heat flux and temperature profiles in a polymeric(cellulose acetate) membrane.This study is novel due to the implementation of user defined scalar(UDS) diffusion equation by using user-defined functions(UDFs) infinite volume method(FVM).Some details of the FVM used by the solver are carefully discussed when implementing terms in the governing equation and boundary conditions(BC).The contours of temperature due to high-temperature gradient are reported for steady and unsteady problems.展开更多
文摘Objective To investigate the therapeutic effect of radial surgery in large cerebral metastatic carcinoma. Methods Adopt three-dimensional oriented radial surgery to 15 patients with the biggest diameter of more than 35mm. Observe the variation of clinical symptoms and analysis the change of CT image. Follow up the survival time, complications and the cause of death at the same time. Results Most of the patients got prominent improvement in symptoms. But the imaging change of carcinoma focus was a slow course comparatively. The survival rate in 1 year was 26%. Conclusion Radial surgery is an effective, simple and safe method in the treatment of large cerebral metastatic carcinoma. It has a good control rate with only slight complications.
文摘Based on finite volume method, the pressure drop and heat transfer characteristics of one smooth tube and ten different axisymmetric corrugated tubes, including two with uniform corrugation and eight with non-uniform corrugation, have been studied. A physical model of the corrugated tube was built, then the numerical simulation of the model was carried out and the numerical simulation results were compared with the empirical formula.The results show that: the friction factor decreases with the increase of Reynolds number ranging from 6000 to 57000, the value of which in the corrugated tubes with non-uniform corrugation(tube 03–10) are smaller than those with uniform corrugation(tube 01–02). The geometry parameters of tube(01) have advantages on the heat transfer enhancement in low Reynolds number flow region(from 6000 to 13000) and tube(07–08)have advantages on the heat transfer enhancement in high Reynolds number flow region(from 13000 to 57000). The vortex, existed in each area between two adjacent corrugations called second flow region, is the root of the enhancement on heat transfer in the corrugated tubes. The effectiveness factor decreases with the increasing of Reynolds number and the performances of the corrugated tubes with pitch of 12.5 mm have advantages than these of 10 mm under the same corrugation geometric parameter.
基金supported by the National Natural Science Foundation of China (Grant No. 51176002)National Basic Research Program of China (Grant No. 2011CB710704)funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (Grant No. PHR200906104)
文摘Silver nanofluids with three different volume fractions are prepared by a one-step chemical reduction method(Ultra-sound-assisted Membrane Reaction(UAMR)).The convective heat transfer and friction characteristics of silver nanofluid in micro-pin fin heat sink are investigated experimentally.The results indicate that the pressure drops of nanofluids with different volume fractions have little difference.Compared to the base fluid(polyvinylpyrrolidone(PVP) solution),the pressure drop of nanofluids increases slightly at the same volume flow rate.When the flow rate is small,the increment is not obvious.The in-troduction of surfactant increases the fluid viscosity,so the pressure drops of nanofluids are larger than those of pure water,under the same flow rate.However,the maximum difference is no more than 10%.The volume fraction of silver nanoparticles significantly affects the convection heat transfer coefficient of micro-pin fin heat sink.The presence of nanoparticles improves significantly the heat transfer performance.However,high viscosity of the nanofluids hinders the heat transfer strengthening effect of nanofluids.In the present work,when the volume fraction of silver particles reaches to 0.012%,the thermal resistance of nanofluid gradually becomes lower than that of deionized water,which indicates the integrated heat transfer enhancement of nanofluids.
文摘The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method for engineering problems like membrane separation system.The CFD modeling in this study observes steady and unsteady(transient) heat flux and temperature profiles in a polymeric(cellulose acetate) membrane.This study is novel due to the implementation of user defined scalar(UDS) diffusion equation by using user-defined functions(UDFs) infinite volume method(FVM).Some details of the FVM used by the solver are carefully discussed when implementing terms in the governing equation and boundary conditions(BC).The contours of temperature due to high-temperature gradient are reported for steady and unsteady problems.
