In order to develop high quality wheat varieties with super high yield, a theory which improved the genetic difference between parents by performing radi- ation mutation on them to enhance heterosis was proposed. The ...In order to develop high quality wheat varieties with super high yield, a theory which improved the genetic difference between parents by performing radi- ation mutation on them to enhance heterosis was proposed. The dry seeds treated and planted last year were radiated frequently by X- ray from 2003 to 2004. Then the dry seeds were radiated by high energy X ray combined with nuclear magnetic resonance from 2005 to 2007. We have treated the dry seeds repeatedly for 3 years and gained a variety of aberrant plants. These mutants were used as parents that were hybridized with the best plants in field. It was shown that a lot of mutant plants appeared in the f＇llial generations. After that, we selected big grains and super big grains among them. The result showed that, middle stem plants with big grains and low stem plants with big grains appeared. This phenomenon might be due to the breakthrough of linkage relationship between big grain trait and high stem trait. With the technique practice and materials, the new thoughts and methods were provided for induction and utilization of heterosis of wheat, which created a va- riety of seed selection and breeding materials for breeding super wheat varieties.展开更多
Localized surface electromagnetic resonances in spherical nanoparticles with gain are investigated by using the Mie theory. Due to the coupling between the gain and resonances, super scattering phenomenon is raised an...Localized surface electromagnetic resonances in spherical nanoparticles with gain are investigated by using the Mie theory. Due to the coupling between the gain and resonances, super scattering phenomenon is raised and the total scattering efficiency is increased by over six orders of magnitude. The dual frequency resonance induced by the electric dipole term of the particle is observed. The distributions of electromagnetic field and the Poynting vector around nanoparticles are provided for better understanding different multipole resonances. Finally, the scattering properties of active spherical nanoparticles are investigated when the sizes of nanoparticles are beyond the quasi-static limit. It is noticed that more highorder multipole resonances can be excited with the increase of the radius. Besides, all resonances dominated by multipole magnetic terms can only appear in dielectric materials.展开更多
为实现模拟前端电路的低功耗增益控制,提出了一种基于控制信号频宽比的可变增益放大器VGA(Variable GainAmplifier),该电路以超再生为基础,能够对增益实施精细控制。与传统的大多数可变增益放大器不同的是,提出的VGA电路在数字控制和放...为实现模拟前端电路的低功耗增益控制,提出了一种基于控制信号频宽比的可变增益放大器VGA(Variable GainAmplifier),该电路以超再生为基础,能够对增益实施精细控制。与传统的大多数可变增益放大器不同的是,提出的VGA电路在数字控制和放大器之间的接口并没有使用任何的直流/交流转换器。最终实现的VGA集成电路使用了0.18 mm CMOS技术进行设计,旨在实现低功率消耗。仿真和测试结果均表明,本文提出的放大器在900 m V的线性范围内最大增益为45 d B,总谐波失真为0.5%,功耗为6.4,相比传统的可变增益放大器,表现出更大的增益范围和较低的功耗。展开更多
文摘In order to develop high quality wheat varieties with super high yield, a theory which improved the genetic difference between parents by performing radi- ation mutation on them to enhance heterosis was proposed. The dry seeds treated and planted last year were radiated frequently by X- ray from 2003 to 2004. Then the dry seeds were radiated by high energy X ray combined with nuclear magnetic resonance from 2005 to 2007. We have treated the dry seeds repeatedly for 3 years and gained a variety of aberrant plants. These mutants were used as parents that were hybridized with the best plants in field. It was shown that a lot of mutant plants appeared in the f＇llial generations. After that, we selected big grains and super big grains among them. The result showed that, middle stem plants with big grains and low stem plants with big grains appeared. This phenomenon might be due to the breakthrough of linkage relationship between big grain trait and high stem trait. With the technique practice and materials, the new thoughts and methods were provided for induction and utilization of heterosis of wheat, which created a va- riety of seed selection and breeding materials for breeding super wheat varieties.
基金supported by the National Natural Science Foundation of China(Grant Nos.11174222 and 91230203)
文摘Localized surface electromagnetic resonances in spherical nanoparticles with gain are investigated by using the Mie theory. Due to the coupling between the gain and resonances, super scattering phenomenon is raised and the total scattering efficiency is increased by over six orders of magnitude. The dual frequency resonance induced by the electric dipole term of the particle is observed. The distributions of electromagnetic field and the Poynting vector around nanoparticles are provided for better understanding different multipole resonances. Finally, the scattering properties of active spherical nanoparticles are investigated when the sizes of nanoparticles are beyond the quasi-static limit. It is noticed that more highorder multipole resonances can be excited with the increase of the radius. Besides, all resonances dominated by multipole magnetic terms can only appear in dielectric materials.
文摘为实现模拟前端电路的低功耗增益控制,提出了一种基于控制信号频宽比的可变增益放大器VGA(Variable GainAmplifier),该电路以超再生为基础,能够对增益实施精细控制。与传统的大多数可变增益放大器不同的是,提出的VGA电路在数字控制和放大器之间的接口并没有使用任何的直流/交流转换器。最终实现的VGA集成电路使用了0.18 mm CMOS技术进行设计,旨在实现低功率消耗。仿真和测试结果均表明,本文提出的放大器在900 m V的线性范围内最大增益为45 d B,总谐波失真为0.5%,功耗为6.4,相比传统的可变增益放大器,表现出更大的增益范围和较低的功耗。
