Development of the large neutron imaging system for inertial confinement fusion experiments

Inertial confinement fusion (ICF) requires a high resolution (~10 μm) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser Me?gaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999)]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a (60)Co γ-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)] Neutron core images of 14 MeV with a resolution of 15 μm were obtained and are compared to x-ray images of comparable resolution.     

纳米针尖状质子化聚苯胺负载的单原子铂催化剂实现高效酸性电解水制氢（英文）

开发高性能单原子铂催化剂对酸性电解水制氢领域具有重要意义.在酸性电解液中,氢离子(H⁺)会被水分子包围并形成水合氢离子,这会导致单原子铂活性位点的局部H⁺浓度降低,从而使其析氢反应动力学受到限制.本研究通过将单原子铂负载在纳米针尖状质子化聚苯胺上,它既能捕获水合氢离子中的H⁺,又能通过促进电荷积累以加快H⁺的电化学还原,从而提高单原子铂的析氢反应动力学.结果表明,相比于扁平状质子化聚苯胺负载的单原子铂,针尖状质子化聚苯胺负载的单原子铂的析氢反应转换频率得到显著提高.结合X射线光电子能谱、有限元模拟和电化学行为研究,我们发现局部H⁺富集促使的氢溢流现象对提升纳米针尖状质子化聚苯胺负载的单原子铂催化剂的析氢活性具有重要贡献.     

Diminished macrophage cholesterol removal rate by the altered HDL metabolism in the Nagase analbuminemic rat

Dyslipoproteinemia of the Nagase analbuminemic rat (NAR) is characterized by elevated concentrations of VLDL and LDL attributed to increased rates of liver lipoprotein synthesis. Increased lysophosphatidylcholine (LPC) in NAR HDL has been attributed to high plasma LCAT activity. We show here that, as compared with Sprague-Dawley rats (SDR), NAR plasma triacylglycerol (TAG), total cholesterol (TC), HDL TAG, protein, total phospholipids (PL), LPC, and PS are increased. These alterations rendered the NAR HDL particle more susceptible to the activity of the enzyme hepatic lipoprotein lipase (HL), which otherwise was unaltered in our study. Fractional catabolic rates in blood of the autologous ¹²⁵I-apoHDL (median and lower quartile values), were, respectively, 0.231 and 1.645 (n=10) in NAR as compared with 0.140 and 0.109 (n=10) in SDR (P=0.012), corresponding to synthesis rates of HDL protein of 89.8±33.7 mg/d in NAR and 17.4±6.5 mg/d in SDR (P=0.0122). Furthermore, Swiss mouse macrophage free-cholesterol (FC) efflux rates, measured as the percent [¹⁴C]-cholesterol efflux/6 h, were 8.2±2.3 (n=9) in NAR HDL and 11.2±3.2 (n=10) in SDR HDL (P=0.03). Therefore, in NAR the modification of the HDL composition slows down the cell FC efflux rate, and together with the increased rate of plasma HDL metabolism influences the reverse cholesterol transport system.     

编制《煤矿建设安全规程》的意义

介绍了编制《煤矿建设安全规程》的迫切性和编制应遵循的基本原则;强调了编制《规程》时,应结合煤矿建设工程施工的实际现状,着重解决5个方面的问题。     

某海螺形自由曲面单层网壳结构形态构建和整体稳定分析

通过三维建模软件Rhinoceros及其可视化编程插件Grasshopper,参数化建模出一种海螺形自由曲面网壳结构.采用ANSYS软件对该结构进行几何非线性分析,研究不对称荷载和初始几何缺陷对结构整体稳定性的影响.采用本文的自由曲面建模方法可以方便、快捷、参数化地设计出建筑师想要的不规则曲面建筑.分析表明:该结构对不...     

Ion channel mimetic micropore and nanotube membrane sensors

This paper describes synthetic micropore and nanotube membranes that mimic the function of a ligand-gated ion channel; that is, these membranes can be switched from an "off" state (no or low ion current through the membrane) to an "on" state (higher ion current) in response to the presence of a chemical stimulus. Ion channel mimics based on both microporous alumina and Au nanotube membranes were investigated. The off state was obtained by making the membranes hydrophobic by chemisorbing either a C18 silane (alumina membrane) or a C18 thiol (Au nanotube membrane). Water and electrolyte are forbidden from entering these very hydrophobic pores/nanotubes. The transition to the on state was induced by the partitioning of a hydrophobic ionic species (e.g., a drug or a surfactant) into the membrane. The membrane switches to the on state because at a sufficiently high concentration of this ionic analyte species, the pores/nanotubes flood with water and electrolyte. A pH-responsive membrane was also prepared by attaching a hydrophobic alkyl carboxylic acid silane to the alumina membrane.     

A study of the behaviour of a protected vessel containing LPG during pool fire engulfment

Theoretical and experimental investigations of various methods for protection against fires of vessels containing liquefied petroleum gases (LPG) (safety relief valves, intumescent fire retardant coatings, thermal isolation) have been carried out. A simple mathematical model has been proposed, which describes dependences of various parameters on time. These parameters are temperature, pressure and mass of LPG, temperatures of the vessel's walls and thermal protection layer. The case of total fire engulfment of the vessel with LPG was considered. Experiments have been executed, which were aimed on the investigation of the behaviour of vessels with LPG (50 l), equipped with protective devices during total fire engulfment. It was found out that the safety valve prevented an explosion of the vessels without any other protective measures. The presence of the intumescent fire retardant coating caused a significant delay in operation of the safety valve. A rather good agreement between the theoretical and experimental data was obtained. It has been revealed that the considered methods for protection of LPG vessels are promising in regard to prevention of explosions in these vessels at the fire engulfment.