植入关节内压电陶瓷供能研究

为了研究压电陶瓷在植入人工关节内压力下能量产生特性,该文从理论上分析了坚硬锆钛酸铅(PZT)陶瓷元件的能量产生特性和等效电路,并基于实验结果利用非线性拟和算法得到其等效电路的参数拟和值。1个与4个PZT元件的仿真结果和实验结果非常吻合,从而验证了等效电路的参数拟和值的正确性及PZT元件的供电特性(约1.2 mW)。最后描述了利用压电陶瓷供电的电源电路设计和仿真结果,证明了PZT的能量能转换为电路稳定可用电源。     

运用X射线荧光光谱法对石榴石分类鉴定

本文介绍了运用X射线荧光光谱法对石榴石的化学组成元素进行剖析（定性及半定量分析）,通过化学组分的不同来对石榴石进行分类、鉴定。     

叶绿素荧光量子产量的MODIS遥感算法

从荧光量子产量的原理出发,利用 MODIS 卫星数据建立了一种估算量子产量的算法--φ算法.通过 2006 年 3 月 23 日渤海和北黄海的 MODIS 数据计算了荧光量子产量,并与叶绿素荧光效率(cFE)产品进行了比较.结果表明,φ算法是一种更精确的荧光量子产量的估算算法,它有效地避免了 CFE 存在的几个误差来源:包括未考虑浮游植物的"包裹效应"、使用 412nm 的离水辐亮度反演的浮游植物吸收系数以及积分深度过浅.CFE在大部分海域出现负值,还出现了某些高估点;在有效数据范围内,两者存在明显的线性相关关系.φ算法估算的量子产量最高值在0.05左右,这与其它海区测量的值域范围基本一致.除辽东湾东北部和部分近岸水域外,大部分离岸水域在0.001～0.02的范围内.通过对φ算法的误差来源分析,认为发展一种新的反演 678nm 比吸收系数和平均吸收系数的波段比值算法是可行的,也是改进φ算法精度的有效方法.     

脉冲光源原子吸收光谱仪信号数字处理软件的设计

通过实验室设计的脉冲光源钨丝原子吸收光谱仪,采集到一个分析信号和光源载波叠加的复合信号。为了从中提取原子吸收分析信号,首先对该复合信号进行数值微分,确定光源脉冲载波每个峰的坐标和相应的峰高,算出每个载波峰位相应的吸光度值,绘制吸收峰轮廓图;然后根据辛普森(Simpson)数值积分原理,求出吸收峰的面积,从而得到积分吸光度值。在微软公司的Visual Basic 6．0开发平台上,编写了实现上述功能的软件,以图形和数值的方式,同时输出每次测定结果。该软件系统和钨丝原子吸收光谱仪硬件系统相配合,对铜标准溶液的测试结果为:检出限为0．0133μg/ml,线性范围为0．10- 4．0μg／ml,对1．0μg／ml Cu(n=10)测定的精密度为RSD=4．05％。     

New optical material europium EDTA complex in polyvinyl pyrrolidone films with fluorescence enhanced by silver plasmons

In our search for efficient Luminescent Solar Concentrators (LSC) we have prepared polyvinyl pyrrolidone (PVP) films incorporated by ethylenediamine tetraacetic acid (EDTA) complex of europium and co-doped with silver nanoparticles (NPs). Steady state fluorescence was studied under weak and strong excitation. Dynamical study was performed by second harmonic of Nd laser. Under weak excitation the fluorescence of europium co-doped with silver plasmons increased by a factor of three and excited by continuous laser by a factor of 50. The lifetimes of films doped by the complex were 755 μs and co-doped with silver nanoparticles 946 μs. This is the first finding that the photon density accumulates the number of plasmons interacting with electronic states of europium increasing its transition probability resulting in the strong intensification of fluorescence. In dynamical measurements of lifetimes a single pulse does not provide enough energy to create such number of plasmons.     

基于约束因子限幅控制的双馈感应发电机有功功率平滑控制

在分析双馈感应发电机（doubly-fed induction generator,DFIG）运行特性和传统最大风能追踪控制（maximum power point tracking,MPPT）策略的基础上,给出一种基于约束因子限幅控制的DFIG有功功率平滑控制策略,提出功率输出限幅值可调的控制思想,结合发电机转速控制和风力机变桨距控制来实现输出功率保持在任意给定值。给出了约束因子的表达式和取值规则。在Matlab／Simulink仿真平台上采用所提平滑控制策略,对一个9MW风电场的有功功率输出特性进行研究,计算了2种控制策略下输出功率的平滑性能指标和方差值。实验结果表明,与传统最大风能追踪控制策略相比,所提出的平滑控制策略能显著减小发电机输出功率的波动,优化了系统的电能质量。     

DG integrated multistage distribution system expansion planning

In this paper, a framework is presented to solve the problem of multistage distribution system expansion planning in which installation and/or reinforcement of substations, feeders and distributed generation units are taken into consideration as possible solutions for system capacity expansion. The proposed formulation considers investment, operation, and outage costs of the system. The expansion methodology is based on pseudo-dynamic procedure. A combined genetic algorithm (GA) and optimal power flow (OPF) is developed as an optimization tool to solve the problem. The performance of the proposed approach is assessed and illustrated by numerical studies on a typical distribution system.     

电网规划中考虑风电场影响的最小切负荷量研究

提出应用鲁棒线性优化理论来研究电网规划中含多个风电场的最小切负荷量计算问题,为含多个风电场的系统安全性研究提供了一条新的思路。根据Seng-Cheol Kang提出的鲁棒线性优化理论,建立电网规划中考虑风电场影响的最小切负荷量模型。该模型以出力上下限和出力期望值来描述风电场的出力,最终转化为一确定性的线性规划问题并进行求解。在计及或不计及发电机调整的情况下,该模型均能够给出最安全的切负荷方案,除此以外还能给出更多介于最可靠与最经济之间的切负荷方案,实现灵活决策;在计及发电机出力可调的情况下,该模型能够给出相应的发电机出力方案;该模型能够初步给出各种切负荷方案下电网规划方案的可靠程度。基于修正的Garver’s 6节点系统和修正的巴西南部46节点系统算例测试结果验证了该方法的有效性。     

神经网络在组合电路多故障测试生成算法中的应用

介绍了一种基于神经网络的组合电路多故障测试生成算法.根据故障转换方法将组合电路的多故障测试生成问题转化为单故障测试生成问题,利用Hopfield神经网络模型将组合电路表示成对应的神经网络,通过建立被测电路的约束网络,构造神经网络的能量函数,使组合电路的测试矢量对应神经网络能量函数的最小值点.将测试生成问题数学化,并使用遗传算法求解能量函数的最小值点得到多故障电路的测试矢量.标准电路的实验表明,该测试算法有效可行.     

Content of various elements in different parts of the tea plant and in infusions of black tea from Southern India

Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g⁻¹ tea) followed by P (700–1200 μg g⁻¹), Mg (300–700 μg g⁻¹), Ca and A1 (each 150–300 μg⁻¹), Mn (60–150 μg g⁻¹), Cu, Na, Si and Z n (each 6–50 μg g⁻¹), B, Ba, Cr, Fe, Ni and Pb (each Id μg g⁻¹), and Sr, Co and Gd (each <1μg g⁻¹). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.