《X-ray laser takes 3D images of lopsided viruses》

  • 来源专题:上海光机所科技信息监测平台
  • 编译者: petrel
  • 发布时间:2017-10-16
  • X-ray laser takes 3D images of lopsided viruses. Oct 5, 20172017-10-05T14:50:35+0100 Slalom course: the LCLS undulator hall Extremely bright and short-lived pulses of X-rays from a free-electron laser have been used to generate 3D images of virus particles. Unlike existing methods, the technique can be used to identify asymmetries in the structure of biological molecules and could lead to the development of drugs that target molecules whose properties cannot be studied using conven...

  • 《The MASSIVE Survey V.: The X-ray halos of the most massive early-type galaxies in the nearby Universe》

    • 来源专题:中国科学院紫金山天文台科技信息监测服务
    • 编译者:zhoubz
    • 发布时间:2016-04-11
    • Studies of the physical properties of local elliptical galaxies (e.g., gas temperatures, halo masses, stellar kinematics) are shedding new light on galaxy formation. Here we present the hot X-ray gas properties of 33 early-type systems within the MASSIVE galaxy survey sample that have archival Chandra X-ray observations. Through careful X-ray spectral modeling, we derive X-ray luminosities (L_X) and plasma temperatures (T_gas) for the diffuse gas components in these galaxies. We combine the MASSIVE sample with 41 galaxies from the ATLAS^3D survey to investigate the X-ray and optical properties of a statistically significant sample of nearby early-type galaxies across a wide-range of environments. We deduce that all early-type galaxies (independent of galaxy mass and rotational support) follow a universal scaling law such that L_X~T_gas^4.5. When X-ray measurements are performed consistently in apertures set by the galaxy stellar content, the wide-scale environment does not contribute to the intrinsic scatter (~0.5dex) within the scaling relation. We further demonstrate that the scatter in L_X around both K-band luminosity (L_K) and the galaxy stellar velocity dispersion is primarily driven by T_gas, with no clear trends with halo mass, radio power, or angular momentum of the stars. It is not trivial to tie the origin of the gas directly to either the stellar mass or the galaxy potential. Indeed, our data require a steeper relation between L_X, L_K, and sigma_e than predicted by standard mass-loss models. Finally, we find a statistically significant correlation between sigma_e and T_gas, suggesting that T_gas is set by the galaxy potential inside the optical effective radius. We conclude that within the inner-most 10-30kpc region, early-types maintain pressure-supported hot gas, with a minimum T_gas set by the virial temperature, but the majority show evidence for some additional heating. .
  • 《中国3D打印产业规模增长率将超40%,》

    • 来源专题:中科院文献情报制造与材料知识资源中心 | 领域情报网
    • 编译者:冯瑞华
    • 发布时间:2018-06-14
    • 3D打印(3D Printing)是借助三维数字模型设计,通过软件分层离散和数控成型系统,利用激光束、电子束等方法将金属粉末、陶瓷粉末、塑料、细胞组织等特殊材料进行逐层堆积黏结,最终叠加成型,制造出实体产品。 在概念上,同义于工业专业术语中的 “增材制造” 。 伴随着3D打印技术的快速成长和3D打印技术在各个行业领域的渗透,全球3D打印行业继续保持快速增长的势头。 2013-2017年中国及全球3D打印产业规模分析 资料来源:前瞻产业研究院 2017-2022年中国3D打印产业规模预测分析 资料来源:前瞻产业研究院 为促进行业发展,新材料在线®独家打造的3D打印企业名录共分3D打印设备、3D打印材料、加工及应用三大版块,目前已汇聚先临三维、华曙高科、太尔时代等全球170多家3D打印上下游知名企业!