烟丝pH值的变化对卷烟烟气烟碱和感官质量的影响

为了解烟丝pH值对卷烟烟气烟碱和感官质量的影响,用0.2 mol/L盐酸和0.5 mol/L NaOH水溶液分别处理两个牌号卷烟的烟丝,而后测定烟丝的pH值、烟丝烟碱、烟气烟碱和烟气游离烟碱量,并进行了感官评吸.结果表明:①烟丝pH值对其总烟碱和烟气烟碱量没有明显影响;②同一牌号卷烟,烟气游离烟碱量与烟丝pH值极显著正相关;③烟气劲头随着烟丝pH值的增大而增大,而其它感官评吸指标则变化不大.因此,通过调节烟丝pH值可在一定范围内改变其烟气的游离烟碱量和劲头.     

THERMAL PROPERTIES OF RADISH AND ALFALFA SEEDS

Thermal conductivity, specific heat, and density were measured in a temperature range of 30C to 80C, and moisture content of 4.6% to 6.5% for radish seeds, 5.0% to 7.3% for alfalfa seeds typically encountered in the radio frequency dielectric heating for seeds. Thermal conductivity and specific heat were determined using a linear heat source probe and a modified calorimeter method, respectively. Thermal conductivity of radish and alfalfa seeds ranged from 0.050 to 0.091 W/mC (SD: 0.011) and 0.075 to 0.120 W/mC (SD: 0.012), respectively. Specific heat was in the range of 0.290 to 0.479 kJ/kgC (SD: 0.051) for radish seeds and 0.333 to 0.593 kJ/kgC (SD: 0.076) for alfalfa seeds. Density of radish and alfalfa seeds ranged from 684 to 675 kg/m³ (SD: 5.592) and 819 to 804 kg/m³ (SD: 8.921), respectively. Thermal diffusivity of the seeds was also determined, and the values varied from 25.13 × 10^?8 to 34.47 × 10^?8 m²/s for radish seeds and 27.14 × 10^?8 to 29.73 × 10^?8 m²/s for alfalfa seeds. Regression models were fitted to the experimental data for each thermal property, and showed second order polynomial relationships with temperature and moisture content.     

基于Transformer的多任务暂态稳定评估

电力系统中的暂态功角稳定和暂态电压稳定对于系统安全运行至关重要,而可再生能源接入比例不断提高和核心设备的电力电子化使得传统的暂态稳定评估方法难以适用。因此,本文提出一种基于Transformer的多任务暂态稳定评估模型。该模型利用Transformer的自注意力机制打破传统循环神经网络的串行计算结构,并行计算暂态过程中各个时间点间的相互关系,快速高效的提取时序特征,并且采用门控多任务学习方法同时评估暂态电压和暂态功角稳定问题,提升模型计算精度和计算效率。本文在IEEE10机39节点系统以及含新能源系统中进行仿真和测试验证了本文提出方法的有效性。     

遥观南枢纽泵站工程水泵机组选型研究

遥观南枢纽泵站工程是新沟河延伸拓浚工程的干河枢纽工程之一,其主要任务是抽排武进港地区的水入京杭大运河,兼顾排涝。该泵站设计净扬程仅为0.7m,属超低扬程泵站。根据已建泵站工程模型泵装置试验成果,从水力性能、工程投资、施工和运行管理等方面进行综合比较,选用了已在溧阳新村枢纽成功应用的贯流泵水力模型。考虑到该泵站的最大扬程接近设计扬程的3倍,还对电机定速和调速方案进行了投资及运行成本比较,发现调速方案机泵投资较大,但运行成本的降低并不显著,因此最终采用定速方案。