设计并实现了一款具备200 m A输出电流能力的开关电容电压反转器,可用于有源相控阵雷达T/R组件中正负电源转换。采用无感式设计简化了开关电源的复杂外围,有效减小了体积。对开关电容电压反转器的系统结构、电路和版图技术进行研究,进...设计并实现了一款具备200 m A输出电流能力的开关电容电压反转器,可用于有源相控阵雷达T/R组件中正负电源转换。采用无感式设计简化了开关电源的复杂外围,有效减小了体积。对开关电容电压反转器的系统结构、电路和版图技术进行研究,进行了结构设计及振荡器、互补时钟、开关驱动等电路设计,并采用0. 6μm Trench SOI CMOS工艺对该产品进行设计和生产制造。实现了最高输入电压＋8 V转输出电压-8 V,最高带载200 m A的开关电容电压反转器产品,外围仅采用储能电容即可实现正负电源转换,满足了T/R组件技术指标和小型化要求。展开更多
The study reveals analytically on the 3-dimensional viscous time-dependent gyrotactic bioconvection in swirling nanofluid flow past from a rotating disk.It is known that the deformation of the disk is along the radial...The study reveals analytically on the 3-dimensional viscous time-dependent gyrotactic bioconvection in swirling nanofluid flow past from a rotating disk.It is known that the deformation of the disk is along the radial direction.In addition to that Stefan blowing is considered.The Buongiorno nanofluid model is taken care of assuming the fluid to be dilute and we find Brownian motion and thermophoresis have dominant role on nanoscale unit.The primitive mass conservation equation,radial,tangential and axial momentum,heat,nano-particle concentration and micro-organism density function are developed in a cylindrical polar coordinate system with appropriate wall(disk surface)and free stream boundary conditions.This highly nonlinear,strongly coupled system of unsteady partial differential equations is normalized with the classical von Kármán and other transformations to render the boundary value problem into an ordinary differential system.The emerging 11th order system features an extensive range of dimensionless flow parameters,i.e.,disk stretching rate,Brownian motion,thermophoresis,bioconvection Lewis number,unsteadiness parameter,ordinary Lewis number,Prandtl number,mass convective Biot number,Péclet number and Stefan blowing parameter.Solutions of the system are obtained with developed semi-analytical technique,i.e.,Adomian decomposition method.Validation of the said problem is also conducted with earlier literature computed by Runge-Kutta shooting technique.展开更多
Combining a detailed catalytic surface reaction mechanism with noble metal and promoter elementary reactions, a new three-way catalytic converter(TWC) reaction mechanism is established. Based on the new mechanism, ste...Combining a detailed catalytic surface reaction mechanism with noble metal and promoter elementary reactions, a new three-way catalytic converter(TWC) reaction mechanism is established. Based on the new mechanism, steady condition numerical simulation is carried out, and the change of light-off temperatures and conversion efficiency with various SO2 contents is obtained. By grey relational analysis(GRA), the relational grade between conversion efficiency and SO2 content is obtained. And, the result shows that SO2 content has the most important influence on C3H6 and NOX conversion efficiency. This provides an important reference to the improvement of activity design of TWC, and may provide guidance for the condition design and optimization of TWC.展开更多
文摘设计并实现了一款具备200 m A输出电流能力的开关电容电压反转器,可用于有源相控阵雷达T/R组件中正负电源转换。采用无感式设计简化了开关电源的复杂外围,有效减小了体积。对开关电容电压反转器的系统结构、电路和版图技术进行研究,进行了结构设计及振荡器、互补时钟、开关驱动等电路设计,并采用0. 6μm Trench SOI CMOS工艺对该产品进行设计和生产制造。实现了最高输入电压＋8 V转输出电压-8 V,最高带载200 m A的开关电容电压反转器产品,外围仅采用储能电容即可实现正负电源转换,满足了T/R组件技术指标和小型化要求。
文摘The study reveals analytically on the 3-dimensional viscous time-dependent gyrotactic bioconvection in swirling nanofluid flow past from a rotating disk.It is known that the deformation of the disk is along the radial direction.In addition to that Stefan blowing is considered.The Buongiorno nanofluid model is taken care of assuming the fluid to be dilute and we find Brownian motion and thermophoresis have dominant role on nanoscale unit.The primitive mass conservation equation,radial,tangential and axial momentum,heat,nano-particle concentration and micro-organism density function are developed in a cylindrical polar coordinate system with appropriate wall(disk surface)and free stream boundary conditions.This highly nonlinear,strongly coupled system of unsteady partial differential equations is normalized with the classical von Kármán and other transformations to render the boundary value problem into an ordinary differential system.The emerging 11th order system features an extensive range of dimensionless flow parameters,i.e.,disk stretching rate,Brownian motion,thermophoresis,bioconvection Lewis number,unsteadiness parameter,ordinary Lewis number,Prandtl number,mass convective Biot number,Péclet number and Stefan blowing parameter.Solutions of the system are obtained with developed semi-analytical technique,i.e.,Adomian decomposition method.Validation of the said problem is also conducted with earlier literature computed by Runge-Kutta shooting technique.
基金Project(2009CK2001) supported by the Science & Technology Development Key Program of Hunan Province STA of ChinaProject supported by the Young Teachers Program of Hunan University,China
文摘Combining a detailed catalytic surface reaction mechanism with noble metal and promoter elementary reactions, a new three-way catalytic converter(TWC) reaction mechanism is established. Based on the new mechanism, steady condition numerical simulation is carried out, and the change of light-off temperatures and conversion efficiency with various SO2 contents is obtained. By grey relational analysis(GRA), the relational grade between conversion efficiency and SO2 content is obtained. And, the result shows that SO2 content has the most important influence on C3H6 and NOX conversion efficiency. This provides an important reference to the improvement of activity design of TWC, and may provide guidance for the condition design and optimization of TWC.
