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91.
92.
Chunxue Xu Yaping Wang Ziyi An Qian Wang Dezhong Sun Zongding Chen 《Analytical letters》2019,52(3):401-410
A multi-elemental certified reference material (CRM) based on Arctic marine sediment was prepared and labeled GBW 07481. Approximately 4.5?kg of the sediment was collected during the third Chinese Arctic Expedition. The sediment was processed in procedures that included air drying, debris removal, drying, and milling. The final product contained particles that were generally smaller than 74?;m representing 99% of the total mass. The powder was poured into clean 10-mL brown glass vials and a total of 300 vials were obtained. The homogeneity and stability were preliminarily investigated to assess the suitability of the marine sediment as a candidate CRM. The candidate material was demonstrated to be suitable for this purpose; and hence the certification project was accomplished with nine reputable laboratories. More than 10 reliable analytical methods, including inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and x-ray fluorescence (XRF), were used for analyzing the sediment for 68 elements. The results should be useful for assessing the analytical accuracy of major, minor, and trace elements in marine sediments. Therefore, the CRM is expected to play an important role in Arctic geochemical surveys and environmental assessment. 相似文献
93.
Dezhong Zou Liquing Sun J. J. Aklonis R. Salovey 《Journal of polymer science. Part A, Polymer chemistry》1992,30(7):1463-1475
Monodisperse crosslinked polystyrene (PS) and polymethacrylate (PMA) beads of sizes greater than 1 μm in diameter are prepared by particle nucleation onto pre-existing polymer seeds in a multistage emulsion polymerization, in the absence of emulsifier. An adequate seed number concentration, which decreases with increasing seed size, is necessary to achieve monodisperse beads. Monodisperse multicomposition beads are prepared by polymerizing styrene onto PMA seeds, but not by polymerizing methyl methacrylate onto PS seeds. Phase separation in growing seed particles or surface polymerization following free radical capture may lead to the formation of asymmetric shaped particles. 相似文献
94.
95.
二维网状冠醚配合物-苯并15-冠-5、二苯并18-冠-6与Na_2[Pt(SCN)_6]配合物的合成与结构 总被引:2,自引:0,他引:2
合成了苯并15-冠-5、二苯并18-冠-6与Na_2[Pt(SCN)_6]的配合物:[Na(B15- C-5)]_2[Pt(SCN)_6] (1),[Na(DB18-C-6)]_2[Pt(SCN)_6] (2),并通过元素分析 、红外光谱、单晶X射线衍射进行了表征。1为单斜晶系,空间群P2_1/c,a = 1. 0974(5) nm,b = 1.5187(7) nm,c = 1.3632(6) nm,β = 96.407(7)°,V = 2. 2568(18) nm~3,Z = 2,D_(calcd) = 1.746 g/cm~3,F(000) = 1184,R_1 = 0. 0357,wR_2 = 0.0868。 2为三斜晶系,空间群 P1-bar,a = 1.2500(3) nm,b = 1.2825(3) nm,c = 1.9342(4) nm,α = 106.82(3)°,β = 102.51(3)°,γ = 103.04(3)°,V = 2.7562 nm~3,Z = 2,D_(calcd) = 1.579 g/cm~3,F(000) = 1316,R_1 = 0.0364,wR_2 = 0.0771。配合物分别由两个[Na(B15-C-5)]~+, [Na(DB18-C-6)]~+配阳离子和一个[Pt(SCN)_6]~(2-)配阴离子组成。配阳离子和配 阴离子通过Na-N键形成二维网状结构。 相似文献
96.
Experimental study on the effects of shear induced structure in a drag-reducing surfactant solution flow 总被引:1,自引:0,他引:1
Hongxia Zhang Dezhong Wang Hanping Chen 《Archive of Applied Mechanics (Ingenieur Archiv)》2009,79(8):773-778
In this paper, The drag reduction characteristics of surfactant solutions have been experimentally studied, as well as, the
shear viscosities of turbulent drag-reducing surfactant solution have been measured as a function of concentration, shear
rate and temperature by using AG-G2 (TA Instruments, New Castle, USA) rheometer. In comparison the rheological property with
the macroscopic behavior of the solutions in turbulent channel flow, a deeper insight into the mechanisms of drag-reducing
surfactant solution has been obtained. For no shear induced structure of surfactant solutions they just show features shear
thinning, but the drag reduction is very significant phenomenon. Surfactant solution of the shear induced structure is not
a surfactant fluid drag reduction of the necessary elements. 相似文献
97.
98.
紫外光催化氧化在环境水质分析中的应用 总被引:3,自引:0,他引:3
紫外光催化氧化是近年来环境水质分析中采用的一种样品预处理新技术,目前在国内环境监测领域还应用得不多。本文结合笔者近期的工作,介绍了紫外光催化氧化的原理、特点、设备及其在环境水质分析中的应用,并简介了微波辅助紫外光催化氧化和超声波-紫外光氧化两种最新技术。 相似文献
99.
Baoliang Zhang Qiuyu Zhang Hepeng Zhang Xinlong Fan Dezhong Yin Xiangjie Li Wei Li 《Particuology》2013,11(5):574-580
This paper describes a novel chemical method for preparing SiO2/TiO2 Janus particles. First, polystyrene (PSt)/SiO2 particles with a raspberry-like structure are prepared by electrostatic assembly. The influences of the reaction time of sulfonation and the treatment times of polyelectrolyte solutions (PDADMAC, PSS) on PSt and SiO2 are investigated with respect to the surface charge density of the particles. SiO2/TiO2 Janus particles are then obtained by hydrolysis of butyl titanate on the surface of PSt/SiO2 particles followed by a calcination process. Particle size analyzer, Zeta potential instrument, FTIR, TEM and SEM are used to characterize the particle size, the amount of charge on the surface of PSt and SiO2 particles and the compositions and morphologies of PSt/SiO2, SiO2/TiO2 and PSt/SiO2/TiO2. The diameters of the PSt, SiO2, PSt/SiO2 and SiO2/TiO2 particles are 2.0 μm, 303 nm, 2.7 μm and 330 nm, respectively. 相似文献
100.
影响MFC产电能力及污水净化的非生物因素研究 总被引:1,自引:0,他引:1
以厌氧污泥接种模拟生活污水, 构建双室无介体型微生物燃料电池(MFC). 以输出功率密度、库仑效率和CODCr(化学需氧量)去除率为评价指标, 采用正交设计考察4种非生物因素(即阴、阳极材料、底物和电子受体)对MFC产电及污水净化的影响. 在此基础上进一步探讨阴极离子浓度对电能输出的影响. 结果表明: 对MFC产能及污水净化的影响因素顺序为: 电子受体>阳极>阴极>底物, 最优组合为碳毡-乳酸钠-不锈钢板-铁氰化钾+溶解氧|向阴极液中投加NaCl可使产电能力显著增强, 最佳投加量为150 mmol•L-1. 同时, 阴极室定期添加铁氰化钾可维持电流稳定. 试验中, 葡萄糖型、乳酸钠型以及混合型底物模拟污水的CODCr均得到有效去除, 平均去除率达85.2%, 显示了研究的MFC具有很强的产电和污水净化能力. 相似文献