P25对TiO_2镀膜光催化活性的影响

通过向钛酸四正丁酯溶胶中添加纳米级TiO2粉末（P25）,来提高煅烧TiO2镀层的光催化活性。用不锈钢丝网作为煅烧TiO2镀层载体,以甲基橙降解效果来衡量TiO2镀层的光催化活性。实验结果表明,当溶胶中P25添加量为1g／L、镀膜次数为4次时,镀层光催化活性达到最大,150min内甲基橙降解率达到69．8％。     

高耐候Q355GNHDZ25钢板的研制

针对GB/T 4171-2008标准对高耐候Q355GNHDZ25钢板的要求,通过合理的化学成分设计,结合CCT曲线的计算,制定了合理的冶炼、加热及轧制工艺.所试制的Q355GNHDZ25钢板组织均匀细小,钢质纯净,具有良好的抗层状撕裂性能和耐大气腐蚀性能,并兼顾了优异的低温冲击韧性和强度,完全满足标准的要求.     

Vitamin D and Death by Sunshine

Exposure to sunlight is the major cause of skin cancer. Ultraviolet radiation (UV) from the sun causes damage to DNA by direct absorption and can cause skin cell death. UV also causes production of reactive oxygen species that may interact with DNA to indirectly cause oxidative DNA damage. UV increases accumulation of p53 in skin cells, which upregulates repair genes but promotes death of irreparably damaged cells. A benefit of sunlight is vitamin D, which is formed following exposure of 7-dehydrocholesterol in skin cells to UV. The relatively inert vitamin D is metabolized to various biologically active compounds, including 1,25-dihydroxyvitamin D3. Therapeutic use of vitamin D compounds has proven beneficial in several cancer types, but more recently these compounds have been shown to prevent UV-induced cell death and DNA damage in human skin cells. Here, we discuss the effects of vitamin D compounds in skin cells that have been exposed to UV. Specifically, we examine the various signaling pathways involved in the vitamin D-induced protection of skin cells from UV.     

BRIGADIER JOHN TILTMAN: ONE OF BRITAIN'S FINEST CRYPTOLOGISTS

Biography of Brigadier John Tiltman, who worked as a cryptologist for the British and American governments from 1920 to 1980.     

A viscous titania paste with a single coating-sintering step for 8–24 μm thick,high-haze,high-quality TiO2 films of dye-sensitized solar cells

A viscous TiO₂ paste was prepared by ball-milling commercially available P25 with ethylene glycol and citric acid. The conventional three- or four-fold deposition process was replaced by a single coating-sintering step of TiO₂ compound. That is coating the paste on Fluorine-doped SnO₂ conductive glass, followed by sintering at high temperature. TiO₂ films varying from 8 μm to 24 μm could be fabricated by this single coating-sintering step. The high viscosity of the paste, the esterification between ethylene glycol and citric acid and the subsequently polyester decomposition in the sintering process were the reasons to make high-quality thick film without cracking and delamination. 7.36% photoelectrical-conversion efficiency was achieved by using the photoelectrode with its P25 film thickness of 14.3 μm. Therefore, the paste would have promising applications for industrial production because of its low-price and simple process.     

Pilot-scale gasification of woody biomass

The gasification of pine and mixed-hardwood chips has been carried out in a pilot-scale system at a range of gas flow rates. Consuming ∼17-30 kgh⁻¹ of feedstock, the producer gas was composed of ∼200 dm³ m⁻³ carbon monoxide, 12 dm³ m⁻³ carbon dioxide, 30 dm³ m⁻³ methane and 190 dm³ m⁻³ hydrogen, with an energy content of ∼6 MJ m⁻³ for both feedstocks. It was found that the efficiency of the system was enhanced at higher flow rates.     

Drivers of non-revenue water: A cross-national analysis

Reducing water losses is seen as key to sustainable water management, but turns out to be challenging. This paper applies a panel data analysis with fixed effects to assess the major drivers of non-revenue water, some of which are under the control of utilities and some of which are not. The analysis finds that the most important drivers are population density per kilometer of network and type of distribution network, which are mostly resulting from urbanization patterns which are factors mostly out of the control of the utility. Yet, low opportunity costs of water losses and high repair costs of water losses have an important adverse effect on water loss reduction. We also found that the country environment in which the utility operates has an important impact on non-revenue water levels.