低强物件抗压强度试验装置研制与测试

测量低强物件抗压强度的试验装置研究尚少.文中利用研发的低强物件抗压强度试验装置,对6个方形竹管试件进行轴压性能试验,分析了试件破坏特征、承载力和延性等.研究表明研发的试验装置满足低强物件抗压强度试验需求,竹管试验验证了装置的可靠性和测量精度.     

多段支持度数据频繁模式关联规则挖掘仿真

针对传统数据关联挖掘过程只适用于单段数据集,导致内存负担重、挖掘频繁项集效率不高等问题,提出一种多段支持度数据频繁模式关联规则挖掘方法.运用多支持度算法对数据集逐步搜索,数据集按照数据项的MIS大小有序排列,采用最小值作为最小支持度,确保该算法的地推性.构建FP_ tree树,利用FP_tree算法对待选项实施剪枝,从...     

引江济淮工程水源区和受水区干旱遭遇风险

干旱遭遇会严重影响跨流域调水工程的效益发挥,为科学评估引江济淮工程水源区和受水区的干旱遭遇风险,采用标准化降水蒸散指数（standardized?precipitation?evapotranspiration?index,SPEI）和 Copula 理论构建水源区和受水区干旱指数的联合分布,分析历史和未来两个区域干旱演变规律以及干旱遭遇风险变化。结果表明：1960—2020 年水源区和受水区发生干旱的频率分别为 27.32% 和 29.78%;未来情景下两个区域干旱发生频率均有明显增加,尤其高排放情景下特旱发生频率增加超过 10%;非汛期水源区和受水区同时发生干旱的概率比汛期高 5.49%;未来汛期和全年干旱遭遇频率预计有明显增加,非汛期干旱遭遇频率略有降低;在中高排放情景下（SSP2-4.5 和 SSP5-8.5）,远期干旱遭遇频率相对更高。干旱遭遇风险增加对跨流域调水工程效益发挥带来了巨大挑战,因此迫切需要制定适应性策略,为调水工程正常运行管理和水资源可持续利用提供保障。     

HPLC检测NG/BTTN混合硝酸酯生产洗涤废水的成分及含量

为了确定硝化甘油/1,2,4-丁三醇三硝酸酯（NG/BTTN）混合硝酸酯生产洗涤废水成分和含量,开展了高效液相色谱（HPLC）梯度洗脱法检测洗涤废水的工作,确定色谱条件如下：固定相为C18（250 mm×4.6 mm,5 μm）色谱柱,流动相为乙腈/水溶液,检测波长为200 nm。结果表明,在洗涤废水中检出6种有机物,通过化合物的保留时间及其与分配系数LogD的线性关系拟合（7天内取样27次）,确定了NG/BTTN混合硝酸酯生产洗涤废水中除了NG和BTTN,尚存在1,2-丙三醇二硝酸酯（30.58%~41.20%）、1,3-丙三醇二硝酸酯（110.69%~135.14%）、1,2,4-丁三醇-1,2-二硝酸酯（7.90%~10.63%）和1,2,4-丁三醇-1,4-二硝酸酯（22.55%~27.95%）四种未完全硝化产物,标准偏差均低于10%,并于10 d内取样40次,证明了该方法准确可靠、适用性好,满足工业生产的检测需求。     

大臂耦合运动串级PID复合控制方法研究

针对自动模式下凿岩台车大臂摆动和俯仰因耦合运动难以控制的问题,提出一种大臂耦合运动串级PID复合控制算法。根据大臂机械结构简图分析大臂俯仰和摆动两关节产生耦合运动的原因;分析位置式PID、增量式PID分别适用于串级PID的位置环和速度环,设计出耦合运动串级PID复合控制算法,并解释具体推算过程;通过在样机试验平台上进行搭载测试,验证了该控制算法的有效性和控制系统的稳定性。研究结果表明：该控制算法能有效解决大臂耦合运动问题,串级PID内、外环配合使控制系统稳定性好;在阶跃信号下目标角度的超调量小(0.5%),在斜坡信号下油缸运动速度动态跟随效果好,其角度误差波动率最大为15.87%。     

UCK2 promotes the proliferation,migration, and invasion of trophoblast cells in preeclampsia by activating the STAT3 pathway

Background: Preeclampsia (PE), characterized by hypertension and proteinuria, leads to serious maternal andinfant complications. Uridine-cytidine kinase 2 (UCK2) belongs to the UCK family, a class of enzymes that catalyzes theconversion of uridine and cytidine to monophosphate form. However, the role of UCK2 in PE has not been reported.Methods: The expression of UCK2 was detected in the placenta of PE patients and N(ω)-nitro-L-arginine methyl esterinduced PE mouse model. Through forced up-regulation or down-regulation of UCK2 in vitro, we examined the effects ofUCK2 on the proliferation, apoptosis, migration, and invasion of trophoblast cells. Stattic, the inhibitor of STAT3pathway, was used to investigate whether the STAT3 pathway mediates the biological function of UCK2 introphoblast cells. Results: The present study found that UCK2 showed low expression in the placenta of PE patientsand PE mouse model. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and flow cytometryassays verified that up-regulation of UCK2 promoted the proliferation of trophoblast cells, while the silence of UCK2suppressed cell proliferation. Besides, flow cytometry and TdT-mediated dUTP Nick-End Labeling assaysdemonstrated that knockdown of UCK2 resulted in apoptosis of trophoblast cells. The wound healing and transwellassays showed that the migration and invasion activities of the trophoblast cells were facilitated by the overexpressionof UCK2 and were blocked by the silence of UCK2. Furthermore, the expression of phosphorylated STAT3 wasincreased with the upregulation of UCK2 and decreased with the inhibition of UCK2. When the STAT3 pathway wasblocked by its inhibitor stattic, the promotion effects of UCK2 on trophoblast cells were suppressed. Conclusion:UCK2 promotes the proliferation, migration, and invasion of trophoblast cells, and these effects may be partlymediated by the activation of the STAT3 pathway.