火焰原子吸收光谱法同时测定尿液中钾和钠

采用原子吸收光谱仪同时测定了尿液中钾和钠的含量,并确立了测定钾和钠的优惠条件。加入氯化铯可消除电离干扰,当稀释比例达到1∶1000时,可以消除尿基质的干扰。钾和钠的检测限分别为0.0049mg/L和0.0040mg/L,测定范围分别为0.2～5.0mg/L和0.2～3.0mg/L,方法回收率分别为99.6%~108.7%和99.2%~101.3%,变异系数分别为0.56%~1.08%和0.41%～0.82%。结果表明该方法准确、灵敏度高、简便快速。     

The Impact of the Azo-Chromophore Sort on the Features of the Supramolecular Azopolyimide Films Desired to Be Used as Substrates for Flexible Electronics

High-performance supramolecular polyimide systems were synthesized via a simple and innovative approach using two types of azo-chromophores, leading to concomitant special properties: high thermostability, the ability to be processed in the form of films with high flexibility, adequate morphological features, and good structuring capacity via phase mask ultraviolet (UV) laser irradiation, induced by the presence of the azo groups (–N=N–). The dimension and the anisotropy degree of the micro/nano patterns obtained on the surface of the flexible films (determined by atomic force microscopy) depend on the azo-dye type used in the supramolecular azopolyimide synthesis, which were higher when the azo-chromophore containing a –cyano group (–C≡N) was used. The molecular dynamics method, an excellent tool for an in-depth examination of the intermolecular interactions, was used to explain the morphological aspects. Energetic, dynamic and structural parameters were calculated for the two systems containing azo-chromophores, as well as for the pristine polymer system. It was highlighted that the van der Waals forces make a major contribution to the intermolecular interactions. The results from the combination of the dynamic analysis and the concentration profile explain the better mobility of the polyimide chains with a maximum content of azo groups in the cis configuration compared to the other systems. Taking all these data into account, the surfaces of the films can be tuned as required for the proposed applications, namely as substrates for flexible electronis.     

空气-乙炔火焰原子吸收分光光度法测定铅精矿中微量氧化钙

利用空气 -乙炔火焰原子吸收分光光度法研究了铅精矿中氧化钙的测定 ,采用基体匹配法消除基体铅的干扰 ,选择氯化锶与EDTA作释放剂 ,建立了铅精矿中微量氧化钙的测定方法。该法操作简便 ,精密度和准确度较好 ,方法相对标准偏差为 3.0 4% ,加标回收率在 99%～ 10 1%之间     

Brownian Motion Influence on AFM Exosomes’ Size Measurements

Extracellular vesicles are evaluated by nanoparticle tracking analysis (NTA), providing information on their hydrodynamic diameters, and by atomic force microscopy (AFM) to calculate their geometric diameters. The aim of this study is to explore the influence of Brownian movements in a sample drop and preparation time on imaging-based measurements and to determine the relationship between the geometric and hydrodynamic sizes of the extracellular vesicles measured by the AFM and the NTA, respectively. Exosomes derived from the human prostate cancer cell line PC3 were evaluated by NTA and AFM, and those results were compared with Monte Carlo simulations. The mean size, evaluated by AFM shortly after application on the mica substrate, is less than its real value. It obtains the correct value faster for a thinner sample drop. Fitting the log-normal distribution to the geometric and hydrodynamic diameters leads to the conclusion that the latter could arise from the former by linear scaling by a factor that could be used to characterize the analyzed extracellular vesicles. The size of the vesicles attached to the mica substrate depends on time. The effect of Brownian motion and stretch of the lipid bilayer should be considered in the context of exosome AFM studies.     

一种基于蚁群优化的装备保障任务调度方法

针对现有装备保障任务调度过程复杂、效率低下的问题,提出一种装备保障任务调度方法。基于装备保障任务的执行过程,建立原子保障任务相关度模型,采用三元组实现装备保障的形式化,将装备保障任务调度问题等效为多阶段决策过程,根据优先级将任务序列分解为多个子序列。针对每个子序列计算相关矩阵并构造加权无向图,采用蚁群优化方法对子序列进行求解,并合成为最优任务序列。仿真结果表明该方法具有较好的鲁棒性。     

An improved fabrication method for carbon nanotube probe

An improved arc discharge method is developed to fabricate the carbon nanotube probe. In this method, the silicon probe and the carbon nanotube were manipulated under an optical microscope. When the silicon probe and the carbon nanotube were very close, 30-60 V dc or ae was applied between them, and the carbon nanotube was divided and attached to the end of the silicon probe. Comparing with the arc discharge method, the new method need not coat the silicon probe with metal in advance, which can greatly reduce the fabrication difficulty and cost. The fabricated carbon nanotube probe exhibits the good property of high aspect ratio and can reflect the true topography more accurately than the silicon probe.     

氢化物发生原子荧光光光谱法测定西红花柱头中的硒

应用AFS－230型双道原子荧光光谱计进行了氢化物发生原子荧光光光谱法测定西红花柱头中硒的研究,方法中采用硝酸做介质,并对各种最佳条件条件进行了测定。线性范围为1．5－15μg/L,相关系数R＝0．9999,回收率为90％－975,采用标准曲线法对4种不同产地的西红花干燥柱头中硒进行了测定,该方法操作简单、快速、精密度好,准确性高,检出限较低,经济、便于推广应用。     

基于K-Medoids聚类的多传感器航迹关联算法

为有效解决目标密集环境下的航迹关联问题,提出了一种基于K-Medoids聚类的航迹关联算法.该算法采用局部航迹与系统航迹进行关联的策略,将系统航迹作为Medoids,降低了需要关联的航迹对数量,避免了K-Medoids的固有缺陷,很大程度上提高了关联算法的效率.通过采用无穷范数计算采样点点迹距离求出了两条航迹的近似距离,这使得关联判决能考虑历史和当前航迹,提高了正确关联率.在多传感器多目标环境下讨论了其具体实现过程,仿真实验结果验证了该算法的有效性和优越性.该算法在存在噪音和离群点时,具有很强的健壮性,适合目标密集环境.     

半互补集合的相依切锥和极限法锥的刻画

根据零模函数的变分性质,带有零模约束的优化问题、零模正则问题和零模极小化问题都可以转化为带有半互补约束集合的约束优化问题。而刻画约束优化问题的约束集合的相依切锥和极限法锥,对获得该优化问题的最优性条件起着至关重要的作用。本文主要刻画了半互补集合的相依切锥、正则法锥和极限法锥,丰富了非连续、非凸规划问题的最优性理论,为进一步研究带有零模约束的优化问题、零模正则问题和零模极小化问题奠定了理论基础。     

在氨性介质中原子吸收法测定金精矿中的银和铜

研究了在氨性介质中采用火焰原子吸收分光光度法测定金精矿中的银和铜。结果表明，矿样经盐酸、硝酸预处理，在pH9—10的氨性介质中，以磷酸二氢钾、酒石酸为掩蔽剂消除Fe、Pb、Zn等共存离子的干扰；采用原子吸收法测定银和铜，其方法的RSD分别为Ag1．33％、Cu2．30％。该方法具有操作简单快速、准确度高、成本低等特点。经矿样验证，分析结果可满足选冶工艺生产的要求。