This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is establ...This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is established through optimization modeling. At the same time, data are transferred to single chip microcomputer (SCM) system by pressure sensor and then stepping motor is controlled by SCM. Finally, the intelligent positioning bed is under the control of stepping motor. As a result, the intelligent positioning bed can move reverse to respiratory law. The experimental results showed that this method can reduce the influence of respiration on tumor displacement, improving the accuracy of intelligent positioning bed with simple circuit and low cost at the same time.展开更多
Among the various micro-powers being investigated, betavoltaic batteries are very attractive for numerous applications because of their advantages of high energy density, long life, strong anti-interference, and so on...Among the various micro-powers being investigated, betavoltaic batteries are very attractive for numerous applications because of their advantages of high energy density, long life, strong anti-interference, and so on. Based on the basic principle of the betavoltaic effect, the current paper adopted the Monte Carlo N-Particle code to simulate the transport processes of β particles in semiconductor materials and to establish the calculation formulas for nuclear radiation-generated current, open circuit voltage, and so on. By discussing the effect of minority carrier diffusion length, doping concentration, and junction depth on the property of batteries, the present work concluded that the best parameters for batteries are the use of silicon and the radioisotope Ni-63, i.e., Ni-63 with a mass thickness of 1 mg/cm2, Na=1×1019 cm-3, Nd=3.16×1016 cm-3, junction area of 1 cm2, junction depth of 0.3 μm, and so on. Under these parameters the short-circuit current, open circuit voltage, output power, and conversion efficiency are 573.3 nA, 0.253 V, 99.85 nW, and 4.94%, respectively. Such parameters are valuable for micro-power fields, such as micro-electromechanical systems and pacemakers, among others.展开更多
文摘This paper introduces a design to improve the radiotherapy accuracy of gamma knife. In this design, sensor is used to collect respiratory parameters and tumor displacement (caused by human respiration) model is established through optimization modeling. At the same time, data are transferred to single chip microcomputer (SCM) system by pressure sensor and then stepping motor is controlled by SCM. Finally, the intelligent positioning bed is under the control of stepping motor. As a result, the intelligent positioning bed can move reverse to respiratory law. The experimental results showed that this method can reduce the influence of respiration on tumor displacement, improving the accuracy of intelligent positioning bed with simple circuit and low cost at the same time.
基金supported by the China Postdoctoral Science Foundation Funded Project (Grant No. 20100481140)the Nanjing University of Aeronautics and Astronautics Basic Research Funded Project (Grant No. Y1065-063)
文摘Among the various micro-powers being investigated, betavoltaic batteries are very attractive for numerous applications because of their advantages of high energy density, long life, strong anti-interference, and so on. Based on the basic principle of the betavoltaic effect, the current paper adopted the Monte Carlo N-Particle code to simulate the transport processes of β particles in semiconductor materials and to establish the calculation formulas for nuclear radiation-generated current, open circuit voltage, and so on. By discussing the effect of minority carrier diffusion length, doping concentration, and junction depth on the property of batteries, the present work concluded that the best parameters for batteries are the use of silicon and the radioisotope Ni-63, i.e., Ni-63 with a mass thickness of 1 mg/cm2, Na=1×1019 cm-3, Nd=3.16×1016 cm-3, junction area of 1 cm2, junction depth of 0.3 μm, and so on. Under these parameters the short-circuit current, open circuit voltage, output power, and conversion efficiency are 573.3 nA, 0.253 V, 99.85 nW, and 4.94%, respectively. Such parameters are valuable for micro-power fields, such as micro-electromechanical systems and pacemakers, among others.
