辐射诱导冷却肉脂肪氧化机理与抑制方法研究

探讨了辐照剂量、贮藏效应、氧气含量和抗氧化剂等因素对辐照冷却肉脂肪氧化的影响，提出了抑制辐照冷却肉脂肪氧化的技术方法。结果表明，辐照冷却肉的过氧化值与辐照剂量存在极显著的正相关关系（p〈0．01），随着贮藏时间的延长表现为先升后降；在包装实验中，真空包装和无氧包装（N2＋CO2）可以咀显降低贮藏期间辐照冷却肉的过氧化值和TBARS值（硫代巴比妥酸反应物）；添加抗氧化剂后，辐照冷却肉的脂肪氧化明显降低，其过氧化值和TBARS值在贮藏期间不超过3meq／kg和0．4mgMDA／kg，而对照达到29meq／kg和1．13mgMDA／kg，其中抗氧化剂茶多酚和维生素E起主导作用。     

输电线路边界保护中雷电冲击与故障的识别

输电线路的边界保护原理是在单端利用暂态分量中包含的高频分量是否经过线路边界这一特点构成的 ,当雷电冲击线路时 ,会使边界保护发生误动作。通过大量的仿真分析 ,发现在雷电冲击没有造成短路和造成弧光短路以及普通短路故障情况下 ,由于线路两端的避雷器造成暂态分量的小波谱随着时间的变化规律不同 ,并提取这一差别构成了雷电和短路的识别算法。输电系统的仿真模型采用频率相关模型 ,ZnO避雷器采用IEEE公认的频率相关模型。EMTP仿真验证说明了该算法的正确性。     

分子自组装体系的影响因素及其在纳米材料中的应用

介绍了分子自组装体系的影响因素以及分子自组装技术在纳米材料制备方面的应用,并对聚合物自组装体系及研究进展作了综述.     

SAHPPA: a novel power pinch analysis approach for the design of off-grid hybrid energy systems

This work proposes a novel approach called stand-alone hybrid system power pinch analysis (SAHPPA), which is particularly applicable for the design of off-grid distributed energy generation systems. The enhanced graphical tool employs new ways of utilising the recently introduced demand composite curve and supply composite curve while honouring and adapting fundamental energy systems engineering concepts. The SAHPPA method is capable of optimising the capacity of both the power generators and energy storage for biomass (i.e. non-intermittent) and solar photovoltaic (i.e. intermittent) energy technologies, which is a contribution to the emerging area of power pinch analysis. In addition, the procedure considers all possible efficiency losses in the overall system encompassing the charging–discharging and current inversion processes.     

Phase Transformations of α-Alumina Made from Waste Aluminum via a Precipitation Technique

We report on a recycling project in which α-Al₂O₃ was produced from aluminum cans because no such work has been reported in literature. Heated aluminum cans were mixed with 8.0 M of H₂SO₄ solution to form an Al₂(SO₄)₃ solution. The Al₂(SO₄)₃ salt was contained in a white semi-liquid solution with excess H₂SO₄; some unreacted aluminum pieces were also present. The solution was filtered and mixed with ethanol in a ratio of 2:3, to form a white solid of Al₂(SO₄)₃·18H₂O. The Al₂(SO₄)₃·18H₂O was calcined in an electrical furnace for 3 h at temperatures of 400–1400 °C. The heating and cooling rates were 10 °C/min. XRD was used to investigate the phase changes at different temperatures and XRF was used to determine the elemental composition in the alumina produced. A series of different alumina compositions, made by repeated dehydration and desulfonation of the Al₂(SO₄)₃·18H₂O, is reported. All transitional alumina phases produced at low temperatures were converted to α-Al₂O₃ at high temperatures. The X-ray diffraction results indicated that the α-Al₂O₃ phase was realized when the calcination temperature was at 1200 °C or higher.     

Micro- and nanostructured Al2O3 surfaces for controlled vascular endothelial and smooth muscle cell adhesion and proliferation

The effect of the micro- and nanotopography on vascular cell-surface interaction is investigated using nano- and microstructured Al₂O₃ as model substrate. Two different nanostructured Al₂O₃ surfaces composed of low density (LD) and high density (HD) nanowires (NWs) were synthesized by chemical vapour deposition (CVD) and commercially available microstructured Al₂O₃ plates were used for comparison. A clear diverging response of human umbilical vein endothelial cells (HUVEC) and human umbilical vein smooth muscle cells (HUVSMC) was observed on these nano- and microstructured surfaces. LD Al₂O₃ NWs seem to enhance the proliferation of HUVECs selectively. This selective control of the cell-surface interaction by topography may represent a key issue for the future stent material design.     

Investigation of the impact of global warming on precipitation pattern of Saudi Arabia

This study has been carried out to forecast the impact of global warming on the precipitation pattern of Saudi Arabia by the end of year 2100. Simulation has been done using EdGCM model software (with available 8×10 resolution) developed at Columbia University on which there have been produced global precipitation maps for the seasonal and annual averages for the last 5 years (2096–2100). For each map, EdGCM grid values surrounding Saudi Arabia are used as input to one of the tools of Eagle point software called surface modelling (SM). SM is a new approach for downscaling global climate model results. SM software modelled out isohyets at 0.2 mm/day interval. The results indicate that the present pattern of precipitation (more in winter and less in summer) is going to change by almost equal occurrence of precipitation in all seasons for double_CO₂ (2CO₂) experiment. The 2CO₂ experiment indicates an increase of about 16.05% over the annual average precipitation across the country.