配标溶剂对双区大气压化学电离质谱分析环境烟气标志物3-乙烯基吡啶的影响

为探讨配标溶剂对双区大气压化学电离-质谱(DRAPCI)源内溶剂效应造成的影响,以环境烟气(ETS)标志物3-乙烯基吡啶(3-EP)为研究对象,以环己烷、甲醇、丙酮和乙腈为配标溶剂,考察3-EP在不同溶剂背景下离子化效率的差异,探讨造成差异的原因,并比较不同配标溶剂下方法的分析性能.结果表明:①配标溶剂的选择会影响3-...     

磁流变阻尼器动力学模型及其应用

介绍了磁流变体的特点和磁流变器件在国外研究和发展状况，并讨论了磁流变阻尼器在火炮反后坐装置上的应用。从材料流变特性和动力学、机械学、电磁学的角度出发，建立了磁流阻尼器的动力学模型，应用该模型可由磁流变阻尼器设计参数得到其动力学特性曲线。     

风力发电机组并网运行对电网运行的影响

随着风电场接入电网的容量越来越大,风力发电机组并网运行会对电网安全稳定运行带来不同程度的影响。分析了政府管理对风力发电发展的推动作用,通过建立风力测量及功率预测系统、配置有功功率控制系统等来提高对风电场的运行管理水平,讨论了风电机组并网运行对调度管理的影响,并提出了电网接纳大容量风电场的应对措施。     

纳米材料及其三维结构修饰电极检测多巴胺的研究进展

纳米材料构建的化学修饰电极用于多巴胺电化学检测已经被广泛研究。当前电极研究策略主要为采用复合材料并构建三维结构以增大吸附表面积。本综述总结了目前常用的纳米碳修饰材料与纳米金属修饰材料,比较分析了其表面结构形貌对多巴胺吸附的影响及吸附机制,总结了目前常用的构建三维修饰电极的方法。分析结果表明,相对于一维形貌,三维形貌结构的修饰电极往往具有更好的检测能力,三维结构不仅能显著增大表面积,提供更多的吸附位点,还可能产生“薄膜效应”,该效应在一定程度上能提高响应灵敏度,但超过一定限度会减缓响应时间,第一性原理分析表明,多巴胺在纳米修饰电极材料表面的吸附机制是化学吸附。最后指出了在改进修饰电极结构设计合理性、增强抗干扰性和提高选择性,以及新的检测控制机制分析方面需要进一步研究。     

化学储能电站消防安全风险分析

在整理化学储能电站相关事故案例的基础上,简述了锂电池热失控原因,归纳了当前化学储能电站消防系统存在的不足和存在的消防安全风险,并比较分析储能电池站主流消防技术,针对性地提出储能电站消防安全提升措施.     

Fractional‐order sliding mode control for hybrid drive wind power generation system with disturbances in the grid

The proposal of hybrid drive grid‐connected wind turbine based on speed regulating differential mechanism (SRDM) has been made in this paper to generate constant‐frequency power without fully‐ or partially‐rated frequency converters so as well improve electric power quality. However, disturbances in the power grid including sudden load fluctuation and sub‐synchronous resonance (SSR) can lead to the pulsating torque to act on the shaft section between SG and exciter at the main generator collector, such that the speed regulating accuracy of SRDM is seriously affected. As a result, this paper synthesizes a new‐type fractional‐order sliding mode controller (FOSMC) with a load torque observer (LTO) for the high‐accuracy speed control of permanent magnet synchronous motor (PMSM) in SRDM. Taking advantage of ridge regression algorithm, related parameters including rotational inertia and viscous friction coefficient of speed regulating system are calculated accurately. Finally, comparative experiments are carried out under four cases of mean of 5, 10, 13, and 21 m/s wind speeds to verify the satisfactory performances of designed FOSMC with LTO. Comparative experimental results show that FOSMC with LTO can effectively eliminate undesirable chattering effect. Additionally, under operating conditions of changing wind speeds, SSR, and sudden load fluctuation in power grid, the output speed of SRDM that corresponds directly to the frequency output of SG can be steadily and accurately regulated by using proposed control scheme. SRDM equipped with designed controller enables the power frequency to meet the National Standard of PR China perfectly.     

Analysis of the steady state probability distribution of a manufacturing system under the prioritised hedging point control policy

In order to evaluate the average production cost of a multi-product-type, multi-stage and multi-parallel-machine manufacturing system (denoted as mP/mS/mM), one of the effective ways is to obtain its steady-state probability distribution. Because the two-product-type and multi-parallel-machine system that demand backlog is not allowed can be considered as a basic building block of the mP/mS/mM system, we begin by investigating the method of obtaining its steady-state probability distribution under the prioritised hedging point control policy. Although the shape of the distribution domains of the work-in-process (WIP) levels influences the steady-state probability balance equations, we develop a unified form of the marginal probability balance equations for all the possible shapes of distribution domains, which can be used to calculate the marginal probability distribution for each product type for the two-product-type and multi-parallel-machine system. Furthermore, we extend this analysis method to both the multiple-product-type, multi-parallel-machine, and single-stage system and the more complex mP/mS/mM system, and propose a method to obtain their approximate marginal probability distributions of the WIP levels. Finally, numerical experiments are conducted to verify the accuracy of the proposed method of analysing the steady-state probability distribution of an mP/mS/mM system.     

高效液相色谱法同时测定食品中10种合成着色剂

目的 建立一种高效液相色谱法同时测定食品中10种合成着色剂(柠檬黄、新红、觅菜红、靛蓝、胭脂红、日落黄、诱惑红、亮蓝、喹琳黄、赤藓红).方法 用GB/T 5009.35-2003(食品中人工合成着色剂的测定方法)中试样处理方法制备样品溶液,聚酰胺吸附法提取色素,以甲酵/乙睛(3+1)+乙酸铵(0.02 mol/L,pH =4.0)为流动相,梯度淋洗分离,多波长检测定量.结果 线性范围分别为柠檬黄、觅菜红、靛蓝、胭脂红、日落黄于0.94-30.00p.g/ml,新红于0.94～30.00μg/ml,诱惑红于1.00～32.10μg/ml,亮蓝于0.31～10.00μg/ml,喹琳黄于1.219.68μg/ml,赤藓红于0.76～24.40μg/ml,线性关系良好,相关系数0.999 0～1.000 0,回收率87.5% - 101.4%,RSD 1.3%～5.7%,检出限分别为0.03～ 0.9 mg/kg.结论 该方法简单、准确、灵敏,适用于食品中10种合成着色剂的定量分析.     

Simultaneous recovery of glycyrrhizic acid and liquiritin from Chinese licorice root (Glycyrrhiza uralensis Fisch) by aqueous two-phase system and evaluation biological activities of extracts

Aqueous two-phase system (ATPS) was used for simultaneous purification of glycyrrhizic acid (GA) and liquiritin (LQ) from crude extract of Chinese licorice root. It was revealed that 87% GA and 94% LQ were retrieved in the ATPS top phase, under the optimum conditions of 25% (w/w) ethanol, 30% (w/w) K₂HPO₄ and 4% (w/w) loading sample at 10–40°C. Compared with crude extract, the ATPS top-phase extract exhibited the highest antioxidative activity, but no tyrosinase inhibitory effect. Whereas, the ATPS bottom-phase extract was proved to be effective ABTS radical scavenger and tyrosinase inhibitor, suggesting the potency of the alcohol-salt ATPS purification for the different medicinal purposes.     

基于闭环比例积分控制的膜片式电-气转换器的研制

介绍一种采用喷嘴／挡板机构的膜片式电—气转换器，论述了该转换器核心部件的基本结构、电—气转换原理、闭环反馈控制方法及关键电路设计，并对转换器工作状态进行了实验研究。结果表明，该转换器性能卓越，可广泛应用于工业自动化控制领域。