新组合模型在光电功率预测中的应用

为提高光伏预测要求的精准性,文章提出一种新算法将神经网络和ARMA算法改进组合,构成NEW ARMA-BP模型算法.以某30兆瓦的光伏电站采集的输出功率为输入样本,基于ARMA和BP神经网络算法在Matlab环境下依次搭建了相应的预测模型,预估光伏短期输出量.采用"误差正态检验图"判断基于两种不同算法的误差水平,依据两种单模型预测误差,运用所提出的新方法计算权值并获得新的预测值.基于Matlab的仿真结论验证了组合预测在光伏输出预测领域的适用性.     

两种缓冲材料的应力松弛实验分析

 用逐次残余法分析了聚乙烯和聚苯乙烯缓冲材料的应力松弛试验数据．结果表明可用有限个并联的Ｍａｘｗｅｌ模型来表示这两种材料的应力松弛试验曲线．     

原子荧光光谱法测定白砂糖和红糖中硒含量

目的：测定白砂糖和红糖中硒含量为研制富硒糖提供科学依据。方法采用微波消解-原子荧光光谱法测定白砂糖和红糖中硒含量。结果在确定的最佳仪器条件下,原子荧光光谱法测定白砂糖和红糖中硒的检出限为0.063μg · L-1;白砂糖硒的RSD为2.28％,红糖的RSD为2.13％;白砂糖回收率为103.4％,红糖回收率为99.7％。结论该法具有方法简便、快捷、准确等优点,适用于白砂糖和红糖中硒含量测定。     

Platinum nanoclusters on graphite substrates: a molecular dynamics study

Molecular dynamics simulations are used to investigate the shape and structure evolution of single platinum clusters of cubic and spherical shape containing 256 and 260 atoms, respectively, deposited on a static graphite substrate. The evolution is monitored at variable temperature, and as a function of metal-substrate interactions at constant temperature. The Pt-Pt interactions are modelled with the many-body Sutton-Chen potential, whereas a Lennard-Jones potential is used to describe the Pt-C interactions. Heating and cooling curves calculated between 200 K and 1800 K are used to determine solid-solid and solid-liquid transitions. Structural changes are detected through analyses of density profiles and diffusion coefficients. A clear analogy is observed between temperature-induced wetting phenomena and those resulting from enhancement of the metal-substrate interactions.     

UPLC-MS/MS法同时测定土壤中3种磺酰脲类除草剂残留

建立了QuEChERS法–超高效液相色谱–串联质谱法(UPLC-MS/MS)快速测定土壤中噻吩磺隆、苯磺隆、氯嘧磺隆3种磺酰脲类除草剂的方法。采用振荡提取、QuEChERS法净化方法处理土壤样品,利用UPLC-MS/MS分析,在多反应监测(MRM)模式下以0.1%甲酸水和乙腈为流动相梯度洗脱。3种除草剂在0.5~500μg/L的质量浓度范围内线性关系良好,相关系数为:0.996~0.999。在10,50μg/kg水平下进行加标回收实验,平均回收率为81.4%~92.9%,RSD为5.5%~10.6%,方法检出限(S/N=3)为0.12~0.16μg/kg。方法可用于大量实际土壤样品中3种除草剂的检测。     

热分析联用技术及其在金属材料领域中的应用

热分析联用技术是在热重分析基础上,将多种检测手段并用,准确地研究材料的结构、组成、热反应等特性,从而揭示材料热分解过程本质的技术。在程序升温过程中,利用热分析联用技术对金属材料的质量和热量变化及热分解产物成分等信息进行检测,能更精准地研究金属材料的组成和热分解特性。该文在热重分析法的基础上,着重介绍了其与差热分析、差示扫描量热分析、傅里叶红外光谱分析、质谱分析等分析方法的联用,并以金属材料研究为例,分析了热分析联用技术在金属材料的结构、性能测定等方面的应用,同时展望了热分析联用技术的应用前景。     

AuNPs/Sol-gel复合膜法固定乙酰胆碱酯酶生物传感器检测有机磷农药

基于有机磷农药对乙酰胆碱酯酶(Acetylcholinesterase,AChE)的抑制作用,用金纳米粒子(Au nanoparticles,AuNPs)与壳聚糖/SiO2杂化溶胶-凝胶构成复合固酶基质,将AChE固定于玻碳电极表面,制备了电流型AChE生物传感器选用久效磷进行实验,以氯化硫代乙酰胆碱为底物,建立了电化...     

Relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI

Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m.