人工智能芯片的现状与趋势——中国科学院物理研究所“人工智能”主题讨论侧记

<正>"我设想在未来,我们可能就相当于机器人的宠物狗狗,到那时我也会支持机器人的。"——克劳德·香农2019年7月1日晚,由科技部引进国外智力管理司、中国科学院科学传播局、北京科学技术委员会支持,中国科学院物理研究所承办的第39期科学咖啡馆活动在物理所M楼咖啡厅举行。科技部引进国外智力管理司邱成利处长主持活动。     

冰雪奇境——中国科学院物理研究所“南极探秘”主题讨论侧记

<正>人间若有天堂,应该是南极的模样。——毕淑敏2018年12月17日晚,由科技部引智司、中国科学院科学传播局、北京科学技术委员会支持,中国科学院物理研究所承办的第33期科学咖啡馆活动在物理所M楼咖啡厅举行。活动邀请的是未来学院院长、少年极先锋极地科考活动组委会主任丁琛先生。他有着15次极地考察     

Transverse Rutherford Scattering of Electron-Ion Collision in a Uniformly Magnetized Plasma

Rutherford scattering formula plays an important role in plasma classical transport. It is urgent to investigate influence of magnetic field on the Rutherford scattering since the high magnetic field has been widely used in nowadays magnetic confinement fusion, inertial confinement fusion, and magneto-inertial fusion. In order to elucidate the magnetic field effect in a concise manner, we study the electron-ion collisions transverse to the magnetic field. The scattering angle is defined using th...     

Electron-Electron Collision Term Describing the Reflections Induced Scattering in a Magnetized Plasma

For an electron-electron collision with characteristic scale length larger than the relative gyro-radius of the two colliding electrons, when the initial relative parallel kinetic energy cannot surmount the Coulomb repulsive potential, reflection will occur with interchange of the parallel velocities of the two electrons after the collision. The Fokker–Planck approach is employed to derive the electron collision term C_R describing parallel velocity scattering due to the reflections for a magnetized plasma where the average electron gyro-radius is much smaller than the Debye length but much larger than the Landau length. The electron parallel velocity friction and diffusion coefficients due to the reflections are evaluated, which are found not to depend on the electron perpendicular velocity. By studying the temporal evolution of the H quantity due to C_R, it is found that C_R eventually makes the system relax to a state in which the electron parallel velocity distribution is decoupled from the perpendicular velocity distribution.     

LD泵浦瓦级单模高掺铒中红外光纤激光器(英文)

中红外激光在激光医疗、激光光谱学和红外对抗等领域有着广泛的应用前景.为了获得结构紧凑、便携性好的中红外激光源,采用975nm半导体激光器泵浦高掺铒氟化物双包层光纤实现了2.8μm的中红外光纤激光输出.将光纤耦合输出的中心波长为975nm的半导体激光,经过消像差非球面透镜系统耦合进双包层光纤,激光谐振腔由高反镜和具有4%菲涅耳反射率的光纤端面组成,当注入到增益光纤的泵浦功率高于0.37 W时,获得了中红外激光输出.实验结果表明:中红外光纤激光器中心波长为2.785μm,谱宽0.9nm;工作阈值为0.37W,最大输出功率为0.98W,斜率效率为17%,激光工作模式为单模.利用高掺杂浓度铒离子间的能量转移上转换,获得了高效率瓦级单模中红外光纤激光输出.