超高亮LED的驱动

在简要介绍超高亮LED的特点以及特性的基础上，详细介绍了LED的电阻限流、线性调节器和开关调节器等驱动方式，在此基础上介绍了超高亮LED的驱动芯片MLX10801的功能和应用，并给出了当前主要超高亮LED驱动芯片的主要特点：     

High-flux electron beams from laser wakefield accelerators driven by petawatt lasers

Laser wakefield accelerators (LWFAs) are considered to be one of the most competitive next-generation accelerator candidates.In this paper,we will study the potential high-flux electron beam production of an LWFA driven by petawatt-level laser pulses.In our three-dimensional particle-in-cell simulations,an optimal set of parameters gives ～40 nC of charge with 2 PW laser power,thus ～400 kA of instantaneous current if we assume the electron beam duration is 100 fs.This high flux and its secondary radiation are widely applicable in nuclear and QED physics,industrial imaging,medical and biological studies.     

A high-flux accelerator-based neutron source for fusion technology and materials testing

Advances in high-current linear-accelerator technology since the design of the Fusion Materials Irradiation Test (FMIT) Facility have increased the attractiveness of a deuteriumlithium neutron source for fusion materials and technology testing. This paper discusses the conceptual design of such a source that is aimed at meeting the near-term requirements of a high-flux high-energy International Fusion Materials Irradiation Facility (IFMIF). The concept employs multiple accelerator modules providing deuteron beams to two liquid-lithium jet targets oriented at right angles. This beam/target geometry provides much larger test volumes than can be attained with a single beam and target and produces significant regions of low neutron-flux gradient. A preliminary beam-dynamics design has been obtained for a 250-mA reference accelerator module. Neutron-flux levels and irradiation volumes were calculated for a neutron source incorporating two such modules, and interaction of the beam with the lithium jet was studied using a thermal-hydraulic computer simulation. Approximate cost estimates are provided for a range of beam currents and a possible facility staging sequence is suggested.This work was supported by Los Alamos National Laboratory Program Development Funds under the auspices of the U.S. Department of Energy.Supported in part by an appointment to the U.S. DOE Fusion Energy Postdoctoral Research Program administered by Oak Ridge Associated Universities.     

高通量循环流化床上升管气固流动特性实验研究

以直径0.06 m、高5 m的高通量循环床提升管中气固两相流大量试验数据为基础,考察在高颗粒循环量和较高气体表观流速下,平均粒径为140 mm、密度为2 700 kg/m3的Geldart B 类颗粒气固流动特性。试验发现,截面平均颗粒浓度分布总体上为下浓上稀,并随操作气速的增大而减小,悬浮上升流动结构区域随着颗粒循环速率的增大而向上延伸。滑移因子、截面平均颗粒浓度与无量纲滑移速度之间存在显著相关性。此外,床层总压降和截面平均颗粒浓度随固气质量比的增加而增加,在上升管下部截面平均颗粒浓度受固气质量比的影响比上部大。     

上海光源真空紫外角分辨光电子能谱束线设计

在上海光源上设计了一条光子能量覆盖5~140 eV的高通量、高分辨的真空紫外角分辨光电子能谱束线。本光束线采用准周期椭圆偏振波荡器光源,其周期长度为0.32 m,周期数为14。单色仪采用Dragon型,分为覆盖5~32 eV的低能分支和25~140 eV的高能分支。计算表明,当入射/出射狭缝开启宽度为5/5 μm时,在整个能量扫描范围内,单色仪分辨率可以高达15 000~100 000,光学元件的面型误差对分辨率的影响最大。通量计算显示,样品处s偏振光子通量高达~10¹² phs/s。Shadow追迹模拟结果表明,设计的光束线具有很好的聚焦特性。     

252Cf生产关键技术及展望

²⁵²Cf是一种重要的超钚元素,可用于核反应堆启动、中子照相、中子活化分析、地质勘探等核技术应用及基础科研,目前世界上只有美国和俄罗斯具备²⁵²Cf生产能力。本研究对²⁵²Cf基本性质、国外²⁵²Cf生产现状进行介绍,提出²⁵²Cf生产需攻克的关键技术。     

Robust graphene/poly(vinyl alcohol) aerogel for high-flux and high-purity separation of water-in-oil emulsion and its computational fluid dynamic simulation

Due to the trade-off between purity and flux, the development of high-purity, high-flux oil–water separation materials is still an arduous challenge. Herein, to achieve emulsion separation with high purity and high permeability, fluorinated graphene/poly(vinyl alcohol) aerogel (FGPA) with strong honeycomb was obtained via a facile freeze-drying method, and the separation mechanism was investigated via computational fluid dynamics (CFDs) simulation. The as-prepared FGPA exhibited superhydrophobicity-superoleophobicity and cyclic compression stability. Under the complex pore and superhydrophobicity, FGPA could separate water-in-oil emulsions with droplet sizes several times smaller than their own aperture only under gravity with ultrahigh flux (3255 L m⁻² h⁻¹) and ultrahigh purity (99.9%). Also, the separation process as visualized using simulations revealed that the vortex accelerates the demulsification behavior and promotes the gathering of water droplets rebounding on the superhydrophobic surface, so that the water droplets are intercepted. Therefore, FGPA has broad practical application potential in high-flux and high-purity oil–water emulsion separation.