摘要：For the Chinese-ADS project, to provide enough neutrons to drive the subcritical system, tens of MW spallation targets for the C-ADS are necessary. This is not an easy task. Here we propose a new concept for a gravity-driven dense granular flow target, in which heavy metal grains are chosen as the spallation target material. Compared with currently widely used targets, this conceptual design has advantages with regard to heat removal, thermal shock protection, neutron yield, radiotoxicity reduction, and convenient operation. The gravity-driven dense granular flow target has the potential to easily deal with these issues and to form a foundation for tens of MW spallation targets for cost-effective facilities. Preliminary simulations and experiments have been completed to support this conceptual design.

摘要：Understanding the temperature-dependent hardness of covalent materials is of fundamental scientific interest and crucial technical *** we propose a temperature-dependent hardness formula for zinc-blende structured covalent materials based on the dislocation *** results indicate that at low temperatures,the Vickers hardness is primarily modulated by Poisson’s ratio and the shear modulus,with the latter playing a dominant *** an increase in temperature,the governing mechanism for the plastic deformation switches from shuffle-set dislocation control to glide-set dislocation control,and the hardness decreases precipitously at elevated ***,the intrinsic parameter a3G is revealed for zinc-blende structured covalent materials,which represents the resistance of a material to softening at high *** temperaturedependent hardness model agrees remarkably well with the experimental data of zinc-blende structured covalent *** work not only sheds light on the physical origin of hardness,but also provides a practical guide for the design of superhard materials.

摘要：提出了一种工作在TM_(310)模式下的用于高次模式速调管的新型谐振腔。通过对侧腔电场的离散化,可以有效地增强中间腔和侧腔的电场。当两腔均工作在TM_(310)模式时,新型谐振腔的特性阻抗均高于传统的哑铃型腔。对两种腔体进行了尺寸敏感性分析。在此基础上,设计了一个W频段的射频电路。当向射频电路注入45 mW的输入功率时,获得了52.4 dB的高增益和7.8 kW的峰值输出功率。互作用电路由25 kV、2 A的圆形电子注驱动。该互作用电路的电子效率和3-dB带宽分别为15.6%和120 MHz。

摘要：从纳米尺度到亚纳米尺度甚至到原子尺度的非贵金属粒子的尺寸可控合成对阐明金属催化剂对氧还原反应催化的尺寸效应有重要意义.本文中,我们提出了一种电化学溶出策略,用于在硫掺杂的还原氧化石墨烯上自上而下制备铜纳米粒子、原子簇及单原子.在该方法中,首先电沉积获得铜纳米粒子(约8 nm),而后使用溶出伏安法,通过调控终止电位可控地将铜纳米粒子尺寸降低至原子簇尺度(约2 nm)和单原子尺度(<1 nm).对活性铜物种尺寸的有效调控使我们可以方便地从多尺度研究铜催化氧还原反应中的尺寸效应.结果表明,单原子铜表现出良好的氧还原反应催化性能,其半波电位为0.86 V,电子转移数为3.98,并具有长期稳定性,远优于其他大尺寸铜颗粒.这些研究结果为自上而下制备特定尺寸金属离子提供了新途径,将有利于尺寸可控氧还原电催化剂的未来设计.