Liposomes as vehicles for vitamins E and C: An alternative to fortify orange juice and offer vitamin C protection after heat treatment

Soy phosphatidylcholine-based liposomes were studied as vitamin transporters to be incorporated in orange juice, which is later subjected to pasteurization. These systems allowed the incorporation of vitamins E and C. Stearic acid and calcium stearate were incorporated into liposomes as an alternative to lipid bilayer stabilizers. Calcium ions and essential fatty acids are contained in calcium stearate and soy phosphatidylcholine, respectively, conferring extra nutritional value. Liposomes prepared by the dehydration–rehydration method were tested in a food model system to avoid interference caused by orange juice components. The oxidative stability was analyzed by the thiobarbituric acid method before and after the pasteurization process. Size was analyzed by light scattering also before and after pasteurization, and shape was analyzed by transmission electron microscopy. Percentage encapsulation efficiency (EE%) of vitamins C and E was determined by a centrifugation process. Also, EE% of vitamin C was measured against dialysis for 72 h.Liposomes had a protective effect on antioxidant activity of vitamins before and after pasteurization; even considering that vitamin C is thermolabile. Besides, EE% by centrifugation showed a high encapsulation of vitamins E and C. And the results of dialysis of vitamin C, demonstrated that it was retained by all the systems. Formulations that included stearic acid were the most efficient encapsulating with a 38%.The results showed a relationship between oxidative stability and aggregation, along with changes in size and morphology: peroxidation increases with aggregation. Addition of stearic acid favors oxidative stability and EE% due to a bilayer stabilizing effect.It is important to note that the combination of liposomal formulations and vitamins with orange juice did not change its organoleptic characteristics, and showed microbiological stability after pasteurization and storage at 4 °C for 37 days.     

ZG15Cr1Mo1V与P91管—管对接的焊接工艺

分析了P91和ZG15Cr1Mo1V的材料特点及焊接性能，介绍了2种材料的对接焊试验方法，对焊缝质量进行了评定。     

SA516-C70钢的焊接工艺试验

茂名石化工程公司承建的聚丙烯环管反应器,其主体材料选用美国ASME标准SA672C70-CL22<中温高压用电熔化焊钢管>,该钢管是由美国ASTM标准SA516-C70<中低温压力容器用碳钢板>焊接而成,为制定合理的焊接工艺,保证焊接接头的质量及设备运行的稳定性,文章对SA516-C70钢的焊接性能包括焊接冷裂纹敏感性、返修、热处理、低温韧性等进行了系统、全面的试验研究.研究结果表明,该钢种具有优良的焊接性能和接头综合性能,焊接参数对其低温性能有着重要影响.     

核电设备用SA738Gr.B复合钢板的爆炸焊接试验研究

为了开发高强核电压力容器用复合钢板,实现核电设备压力容器关键部件国产化,对核电设备用SA738Gr.B复合钢板的爆炸焊接和热处理工艺进行了研究,通过试验验证了爆炸焊接理论参数的正确性,对爆炸焊接后的核电设备用SA738Gr.B复合钢板提出了合理的正火和回火工艺,从而实现了核电设备用SA738Gr.B复合钢板各项力学指标...     

The Fort Totten mercury pollution risk assessment: a case history

Operational activities have resulted in mercury in the sediments surrounding Little Bay in Queens, NY. This is adjacent to Fort Totten, a formerly used defense site. Some of the mercury levels in these sediments exceeded New York State screening values. A human health risk assessment was accomplished, based on conservative assumptions. The risk assessment examined the potential for adverse health effects from direct contact with and ingestion of contaminated sediments/surface water and ingestion of biota. Potential exposures to recreational receptors including adults and children were examined. The highest numerical risk results from finfish ingestion and then second for exposure from dermal contact to the sediments. The only exposure pathway showing a hazard quotient greater than unity is finfish ingestion for the child. In summary, overall risk to this mercury exposure is minimal in spite of the state screening value being exceeded.     

回火温度对SA533B钢组织和力学性能的影响

通过光学显微镜和透射电镜,研究了不同回火温度对SA533B钢力学性能、组织及析出行为的影响。结果表明,SA533B钢经880~C淬火和680~C回火后综合力学性能最佳,屈服强度、抗拉强度和延伸率分别为635MPa、750MPa和21％,冲击功120J。     

连铸二冷喷嘴试验装置及自动化控制系统

连铸二次冷却段是连铸机的关键设备，二次冷却控制直接影响连铸坯的内部和外部质量，其特点是要求流量控制范围大。二次冷却水量的控制范围随喷嘴的压力一流量特性而变化，所以测试、分析喷嘴特性尤为重要。宝钢喷嘴试验装置主要是模仿连铸二冷各段内、外弧的冷却工况，对喷嘴的冲击压力特性及水流密度特性、热态特性进行测试，并由测试数据和分析结果给出冷却水量与铸坯冷却状态之间的特性关系，对系统功能及主要控制技术做了介绍。     

实现ICF均匀照明的二元光学器件的混合优化设计

结合模拟退火和遗传算法各自的特点，提出了一种混合算法，用以设计阵列型惯性约束核聚变（ＩＣＦ）均匀照明系统中二元阵列单元的位相分布。混合算法充分利用了遗传算法的并行性及保留一定历史信息的特性，并用模拟退火的温度参数控制收敛性。模拟运算表明，混合算法具有较高的效率及寻优可靠性。用本算法设计的均匀照明阵列，可以得到顶部均匀性为３．２％（ｒｍｓ）、能量利用率接近９０％的焦斑     

带LCD驱动的三相多费率电度表芯片-SA9110A的原理与应用

SA9110A是SAMES公司推出的新型三相多费率（分时计费）电度表芯片。它内部集成了三相电能测量所需的电压/电流检测、A/D转换器、功率计算、LCD驱动等功能电路，因此，该芯片外接少量元件即可构成一个三相多费率电能表，文中给出了SA9110A的原理、特性及应用电路。     

基于视觉感知和MARMA-MRF模型的SAR图像分割

模拟人类视觉感知机制,提出了一种基于多尺度 自回归滑动平均(MARMA,multiscale auto-regressive and moving average model)模型 和Markov随机场(MRF,markov random field)的合成孔径雷达(SAR)图像分割新方法。首先 ,分析人类视觉感知系统的工作机制 和特点,利用SAR的成像机理,构建了SAR图像的金字塔结构和MARMA模型, 以此模拟视觉过程中的空间尺度和朝向感知机制;然后,通过不同尺度上的MRF模型和改 进的模拟退火(SA)算法实现更有效的多尺度分割策略。实验结果表明,本文提出的方法在SA R图像分割任务中有非常良好的表现。