Destabilization of Aqueous Colloidal C60 Nanoparticles in the Presence of Various Organic Matter     

Jung‐Hwan Kwon 《洁净——土壤、空气、水》2012,40(5):472-478

The extractable fraction of aqueous colloidal C₆₀ nanoparticles (nC₆₀) was quantified using a liquid–liquid extraction method in the presence of five types of dissolved organic matter (DOM): Aldrich humic acid (AHA), Suwannee River fulvic acid (SFA), sodium dodecyl sulfate (SDS) micelle, liposomes composed of 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC), and bovine serum albumin (BSA). The changes in toluene extractable fraction highly depended on the type and dose of DOM. Whereas an environmentally relevant concentration of AHA, 2–20 mg L^?1, was sufficient to reduce the nC₆₀ fraction easily destabilized, much higher dose of fulvic acid was needed to result in the similar degree of stabilization. A big contrast between two types of self‐organized DOM, SDS micelle and POPC liposomes, was observed. Although SDS micelle significantly decreased the toluene extractable fraction of nC₆₀ at the dose greater than its critical micelle concentration, no apparent decrease in toluene extractable fraction was found in the presence of POPC liposomes up to 3000 mg L^?1. The toluene extractable fraction of nC₆₀ in the presence of BSA rapidly decreases at lower doses then gradually decreased at higher doses. An equilibrium complexation model was proposed to quantitatively describe the decrease in the extractability of nC₆₀ in the presence of DOM. The observed decrease in the extractability of nC₆₀ was well explained by the model and the complexation of nC₆₀ with DOM was thought to occur close to 1:1 molar ratio except for BSA. The association constants of nC₆₀ with DOM were in the order of BSA, AHA, SFA, and SDS micelle, showing the differences in the affinity to nC₆₀.  相似文献   

应用多传感器多模型融合技术提取滑坡综合信息   总被引：1，自引：0，他引：1  

彭继兵  许强  郭科 《中国地质灾害与防治学报》2005,16(4):109-112

大型滑坡监测时往往会在同一个滑坡体的不同部位布置多个监测点，以了解和控制其整体变形状况。但目前的滑坡预测预报模型只能一次使用一个监测序列。为了充分利用滑坡各个监测点的监测信息进行滑坡预测预报，论文提出了利用多传感器多模型融合技术，从滑坡体多个监测序列中提取滑坡综合监测信息的数学方法。  相似文献   

察尔汗盐湖铷资源利用——从基础认知到技术创新          下载免费PDF全文

高丹丹  李东东  樊燕飞  李武 《盐湖研究》2022,30(3):1-11, 41

铷是诸多高新技术领域中的关键元素。青海察尔汗盐湖卤水中蕴藏着丰富的铷资源,但由于铷浓度极低,且与大量钠、钾、镁等离子共存,提取难度极大。利用已知技术从察尔汗盐湖卤水中直接提取铷难以满足经济性约束的前提,这成为察尔汗盐湖铷资源难以利用的症结之一。本文从理论和实验两个方面分析了NaCl+KCl+RbCl+MgCl₂+H₂O体系中(K,Rb)Cl和铷钾光卤石固溶体—水溶液平衡对察尔汗盐湖卤水中铷分布的制约作用,确定了钾光卤石基固溶体是控制卤水中微量铷进入固相的关键矿物,钾光卤石的形成会使卤水中的铷浓度迅速下降至极低水平。用光卤石矿生产氯化钾,铷几乎全部进入氯化钾产品中,这一结论得到了现场盐田样品分析结果的支持。在上述新认知的启发下,我们设计了从察尔汗盐湖氯化钾产品中浓缩铷的工艺流程,并进行了公斤级小试和吨级放大试验,获得了铷浓度为400 mg/L的富铷料液,其中镁/铷比和钾/铷比均大幅降低;此外,进一步利用本团队成熟的t-BAMBP萃取方法可高效提取氯化铷,其工艺综合成本约为2 090 元/kg,较好满足了察尔汗盐湖铷资源开发的经济性前提。  相似文献   

固相萃取法提取典型海水溶解有机质及其红外光谱和固态¹³C核磁共振表征     

武奕鑫  王孝聪  周振淞  何晨  潘良浩  宋桂雪 《海洋与湖沼》2022,53(6):1360-1369

由于海水盐度大、有机质含量低,从海水中提取和纯化克级溶解性有机质(dissolved organic matter,DOM)一直十分困难。基于Bond Elut PPL固相萃取小柱法进行海水DOM固体样品提取的放大试验,建立DOM自动化调酸、PPL树脂吸附技术,最后形成提纯、冷冻干燥PPL-DOM(通过PPL树脂提取的DOM)完整工艺。采用元素分析、三维荧光光谱、红外光谱和固态¹³C核磁共振(NMR)波谱法进行样品表征。结果表明:(1)该方法对近海表层海水DOM回收率稳定在50%以上,搭建的提取装置DOM日吸附量可达230mg;(2)鳌山湾四个季节批次PPL-DOM整体分析结果表明,样品的元素组成和光谱特征相似,表明方法适用性和稳定性较好;(3)三种水生态环境的PPL-DOM¹³C NMR谱图显示样品的基本特征相似,以烷基碳、碳水化合物碳、芳香碳和羧基碳/酰胺碳为主,其中偶极去相(dipolar dephasing)谱显示了DOM前体化合物来源的差异。多种结果表明放大后的PPL固相萃取法可稳定提取克级DOM样品。  相似文献   

Automatic extraction of geometrical characteristics hidden in ground‐penetrating radar sectional images using simultaneous perturbation artificial bee colony algorithm          下载免费PDF全文

B. Jafrasteh  N. Fathianpour 《Geophysical Prospecting》2017,65(1):324-336

Ground‐penetrating radar is one of the most effective methods of detecting shallow buried objects. Ground‐penetrating radar radargram is a vertical map of the radar pulse reflections that returns from subsurface objects, and in the case of cylindrical objects, it would be a hyperbola. In order to get clear and accurate information on the presence, location, and geometry of the buried objects, the radargrams need to be interpreted. Interpretation of the results is a time‐consuming task and needs an expert with vast knowledge. Development of an automatic interpretation method of B‐scan ground‐penetrating radar images would be an effective and efficient solution to this problem. A novel automatic interpretation method of ground‐penetrating radar images, based on simultaneous perturbation artificial bee colony algorithm using tournament selection strategy, simultaneous perturbation stochastic approximation method, and new search equations, is introduced in this paper. The proposed algorithm is used to extract geometrical parameters, i.e. depth, location, and radius, of buried cylindrical objects in order to assess its accuracy. Synthetic data, simulated using GprMax2D forward modelling program, and real data, surveyed in the campus of Isfahan University of Technology, are used in the assessment. The performance of the proposed method in detecting synthetic hyperbolas is compared with that of the original artificial bee colony algorithm, genetic algorithm, and modified Hough transform. The results show superiority of the proposed algorithm, in detecting synthetic hyperbolas. Furthermore, the performance of the proposed method in estimating depth and radius of pipes in real ground‐penetrating radar images is compared with that of the modified Hough transform. The results indicate higher accuracy of the proposed method in estimating geometrical parameters of the buried cylindrical objects.  相似文献   

A single vs. double spike approach to improve the accuracy of Th measurements in small-volume seawater samples     

Alessia M. Rodriguez y Baena  Juan Carlos Miquel  Pere Masqu  Pavel P. Povinec  Jerome La Rosa 《Marine Chemistry》2006,100(3-4):269

²³⁴Th is a particle-reactive radionuclide widely used to trace biogeochemical oceanic processes occurring over short timescales. During the last few years, small-volume techniques based on the co-precipitation of ²³⁴Th with MnO₂ coupled with beta-counting have been developed as an alternative to large volume gamma-spectrometric techniques. Here a procedure has been developed to enhance quantitative measurement of ²³⁴Th in MnO₂ precipitates. The main objectives were to obtain a purified Th fraction for beta-counting and to determine the chemical recovery of ²³⁴Th using Th spikes and alpha-spectrometry as an alternative to ICP-MS based methods. Two variations of the procedure are presented. In the first “1 spike” method a ²³⁰Th tracer is added to the sample prior to precipitation of MnO₂, and UTEVA® extraction chromatography is used to obtain a NdF₃(Th) purified source that can be used for both beta-counting of ²³⁴Th and alpha-spectrometry of ²³⁰Th. In the “2 spike” method a ²³⁰Th spike is added and the MnO₂(Th) precipitate is directly beta-counted for ²³⁴Th and subsequently spiked with ²²⁸Th or ²²⁹Th prior to UTEVA® purification and alpha-spectrometry. The results confirm the need to process small-volume seawater samples for ²³⁴Th measurement in presence of a yield tracer, and show that both the 1 spike and 2 spike methods allow an accurate and precise determination of ²³⁴Th (relative percent difference, RPD, between expected and mean measured value < 1%; CV between replicate samples < 3%). Our work also suggests that, although the combined analytical uncertainty on total ²³⁴Th measurements accomplished with both versions of the NdF₃ procedure is promising (6% for 2-L samples), the precision of the ²³⁴Th flux estimation will ultimately depend on the degree of disequilibrium between ²³⁴Th and ²³⁸U.  相似文献