This paper presents new beam test results for O^+ beam on a high current Integral Split Ring Radio Frequency Quadruple(ISR RFQ)accelerator.After the upgrading,a new designed 2.45GHz O^+ ECR Ion Source can provide a be...This paper presents new beam test results for O^+ beam on a high current Integral Split Ring Radio Frequency Quadruple(ISR RFQ)accelerator.After the upgrading,a new designed 2.45GHz O^+ ECR Ion Source can provide a beam with macro-puise peak current of 4mA at the injection point behind a 15ram diaphragm,whose O^+ factor is 60%—80% varied with gas flow rate and the normalized rms emittance is less than 0.15πmm·mrad.The accelerated O^+ beam current goes up to 2mA with the transmission of about 80% at 45kW RF power with duty factor 1/6(pulse duration of 1ms and repetition frequency of 166Hz).The upgraded RF power system includes low level RF pulse modulation amplifier,AGC,3W and 20W preamplifiers,1kW driver and 30kW final amplifier,which can output nearly 50kW in pulsed mode.The vacuum has been improved,too.The upgraded 1MeV ISR RFQ can be used as the beam injector of a new designed SFRFQ accelerating system,which is under the construction at Peking University.展开更多
This paper is devoted to a study of the peristaltic motion of a Casson fluid of a non-Newtonian fluid accompanied in a horizontai tube.To characterize the non-Newtonian fluid behavior,we have considered the Casson flu...This paper is devoted to a study of the peristaltic motion of a Casson fluid of a non-Newtonian fluid accompanied in a horizontai tube.To characterize the non-Newtonian fluid behavior,we have considered the Casson fluid model.Suitable similarity transformations are utilized to transform the governing partial differential momentum into the non-linear ordinary differential equations.Exact analytical solutions of these equations are obtained and are the properties of velocity,pressure and profiles are then studied graphically.展开更多
The peristaltic ttow of nanofluids is a relatively new area of research. Scientists are of the opinion that the no-slip conditions at the boundaries are no longer valid and consequently, the first and the second order...The peristaltic ttow of nanofluids is a relatively new area of research. Scientists are of the opinion that the no-slip conditions at the boundaries are no longer valid and consequently, the first and the second order slip conditions should be addressed. In this paper, the effects of slip conditions and the convective boundary conditions at the boundary walls on the peristaltic flow of a viscous nanofluid are investigated for. Also, the exact analytical solutions are obtained for the model. The obtained results are presented through graphs and discussed. The results reveal that the two slip parameters have strong effects on the temperature and the nanoparticles volume fraction profiles. Moreover, it has been seen that the temperature and nanoparticles volume fraction profiles attain certain values when the first slip condition exceeds a specified value. However, no limit value for the second slip parameter has been detected. Further, the effects of the various emerging parameters on the flow and heat transfer characteristics have been presented.展开更多
Intrinsic carrier transport properties of single-walled carbon nanotubes have been probed by two parallel methods on the same individual tubes： The contactless dielectric force microscopy （DFM） technique and the co...Intrinsic carrier transport properties of single-walled carbon nanotubes have been probed by two parallel methods on the same individual tubes： The contactless dielectric force microscopy （DFM） technique and the conventional field-effect transistor （FET） method. The dielectric responses of SWNTs are strongly correlated with electronic transport of the corresponding FETs. The DC bias voltage in DFM plays a role analogous to the gate voltage in FET. A microscopic model based on the general continuity equation and numerical simulation is built to reveal the link between intrinsic properties such as carrier concentration and mobility and the macroscopic observable, i.e. dielectric responses, in DFM experiments. Local transport barriers in nanotubes, which influence the device transport behaviors, are also detected with nanometer scale resolution.展开更多
文摘This paper presents new beam test results for O^+ beam on a high current Integral Split Ring Radio Frequency Quadruple(ISR RFQ)accelerator.After the upgrading,a new designed 2.45GHz O^+ ECR Ion Source can provide a beam with macro-puise peak current of 4mA at the injection point behind a 15ram diaphragm,whose O^+ factor is 60%—80% varied with gas flow rate and the normalized rms emittance is less than 0.15πmm·mrad.The accelerated O^+ beam current goes up to 2mA with the transmission of about 80% at 45kW RF power with duty factor 1/6(pulse duration of 1ms and repetition frequency of 166Hz).The upgraded RF power system includes low level RF pulse modulation amplifier,AGC,3W and 20W preamplifiers,1kW driver and 30kW final amplifier,which can output nearly 50kW in pulsed mode.The vacuum has been improved,too.The upgraded 1MeV ISR RFQ can be used as the beam injector of a new designed SFRFQ accelerating system,which is under the construction at Peking University.
文摘This paper is devoted to a study of the peristaltic motion of a Casson fluid of a non-Newtonian fluid accompanied in a horizontai tube.To characterize the non-Newtonian fluid behavior,we have considered the Casson fluid model.Suitable similarity transformations are utilized to transform the governing partial differential momentum into the non-linear ordinary differential equations.Exact analytical solutions of these equations are obtained and are the properties of velocity,pressure and profiles are then studied graphically.
文摘The peristaltic ttow of nanofluids is a relatively new area of research. Scientists are of the opinion that the no-slip conditions at the boundaries are no longer valid and consequently, the first and the second order slip conditions should be addressed. In this paper, the effects of slip conditions and the convective boundary conditions at the boundary walls on the peristaltic flow of a viscous nanofluid are investigated for. Also, the exact analytical solutions are obtained for the model. The obtained results are presented through graphs and discussed. The results reveal that the two slip parameters have strong effects on the temperature and the nanoparticles volume fraction profiles. Moreover, it has been seen that the temperature and nanoparticles volume fraction profiles attain certain values when the first slip condition exceeds a specified value. However, no limit value for the second slip parameter has been detected. Further, the effects of the various emerging parameters on the flow and heat transfer characteristics have been presented.
文摘Intrinsic carrier transport properties of single-walled carbon nanotubes have been probed by two parallel methods on the same individual tubes： The contactless dielectric force microscopy （DFM） technique and the conventional field-effect transistor （FET） method. The dielectric responses of SWNTs are strongly correlated with electronic transport of the corresponding FETs. The DC bias voltage in DFM plays a role analogous to the gate voltage in FET. A microscopic model based on the general continuity equation and numerical simulation is built to reveal the link between intrinsic properties such as carrier concentration and mobility and the macroscopic observable, i.e. dielectric responses, in DFM experiments. Local transport barriers in nanotubes, which influence the device transport behaviors, are also detected with nanometer scale resolution.
