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961.
Fumiyoshi Ikkai Mitsuhiro Shibayama Shunji Nomura Charles C. Han 《Journal of Polymer Science.Polymer Physics》1996,34(5):939-945
Mesoscopic structures of poly(vinyl alcohol)(SINGLEBOND)Congo red (PVA(SINGLEBOND) CR) complexes in aqueous solutions were investigated in terms of dynamic light scattering (DLS) technique. The intensity-intensity time correlation function, g(2)(t), was analyzed with an equation including a single and a stretched exponential function. Two diffusion coefficients, Df (fast) and Ds (slow) were evaluated. Df was converted to the apparent correlation length, ξapp, via the mode-mode coupling hypothesis. The estimated ξapp was insensitive to the sol(SINGLEBOND)to(SINGLEBOND)gel transition but decreased with CR concentration. This change may be related to the electrostatic screening effect. On the other hand, Ds oscillates with increasing CR concentration at a specific PVA concentration range. This explains well the reentrant sol(SINGLEBOND)gel(SINGLEBOND)sol(SINGLEBOND)gel transition behavior observed in the PVA(SINGLEBOND)CR systems. Ds seems to represent the mobility of the PVA(SINGLEBOND)CR complexes, which annihilates at the gel point. © 1996 John Wiley & Sons, Inc. 相似文献
962.
A combined ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP—MS) system as an element-selective detector has been used for the determination of arsenic compounds. Seven arsenic compounds were separated by cation-exchange chromatography. Subsequently, the separated arsenic compounds were directly introduced into the ICP—MS and were detected at m/z =75. Detection limits for the seven arsenic compounds ranged from 0.8 to 3.8 μg As/l. The IC–ICP–MS system was applied to the determination of arsenic compounds in the urine of dimethylarsinic acid (DMAA)-exposed rats. DMAA was the most abundant arsenic compound detected. Arsenous acid, monomethylarsonic acid and trimethylarsine oxide were also detected. 相似文献
963.
The electrochemical polymerization technique has been successfully applied to produce conducting polymer film of controlled ion exchange properties. Polypyrrole films were prepared by electro-oxidative polymerization with doping some alkylsulfonates or Nafion. The ion exchange characteristics across polypyrrole films were examined by means of a novel electrochemical technique, namely, the in situ electrochemical quartz crystal microbalance (EQCM) method. According to EQCM measurements, exchanging ion species was found to be successfully controlled by changing the hydrophilic–hydrophobic balance of the incorporated sulfonated-based dopants. The film's characteristics became anion- to cation-exchanging as the dopants became more hydrophobic in nature. The polypyrrole–Nafion(poly(perfluoroethylene sulfonate)) composite film became to be a complete cation exchanger. 相似文献
964.
965.
966.
电弧离子镀技术中脉冲偏压对TiN薄膜的影响 总被引:1,自引:0,他引:1
用正交设计实验研究了电弧离子镀技术中采用脉冲偏压以后各种参数对沉积TiN薄膜性能的影响.研究表明,与直流偏压相比,直流叠加脉冲偏压能更好地细化颗粒,降低薄膜的表面粗糙度,提高沉积速率.对实验结果的方差分析显示:气氛和频率是降低表面粗糙度、提高沉积速率的主要因素. 相似文献
967.
用方波溶出伏安法测定松花蛋中痕量铅,在抗坏血酸存在下,以0.1 mol/L硝酸溶液为底液,玻碳电极为工作电极,测得铅的溶出峰电位是-0.48 V。峰高与铅浓度在1.00×10-4~1.00×10-6mol/L范围内呈良好的线性关系,铅的检出限为5.00×10-8mol/L,回收率为90%~108%。此法干扰较少,易于掩蔽,灵敏度较高,适用于松花蛋等食品中微量铅的测定。 相似文献
968.
HoU Baoxiu MA Linlin ZANG Xiaohuan SHANG Ningzhao SONG Jianmin ZHAO Xiaoxian WANG Chun QI Jian WANG Jiangyan YU Ranbo 《高等学校化学研究》2021,37(2):265-273
An easy and delicate approach using cheap carbon source as conductive materials to construct 3D sequential porous structural Na3V2(PO4)3/C(NVP/C)with high performance for cathode materials of sodium ion battery is highly desired.In this paper,the NVP/C with 3D sequential porous structure is constructed by a delicate approach named as“cooking porridge”including evaporation and calcination stages.Especially,during evaporation,the viscosity of NVP/C precursor is optimized by controlling the adding quantity of citric acid,thus leading to a 3D sequential porous structure with a high specific surface area.Furthermore,the NVP/C with a 3D sequential porous structure enables the electrolyte to interior easily,providing more active sites for redox reaction and shortening the diffusion path of electron and sodium ion.Therefore,benefited from its unique structure,as cathode material of sodium ion batteries,the 3D sequential porous structural NVP/C exhibits high specific capacities(115.7,88.9 and 74.4 mA·h/g at current rates of 1,20 and 50 C,respectively)and excellent cycling stability(107.5 and 80.4 mA·h/g are remained at a current density of 1 C after 500 cycles and at a current density of 20 C after 2200 cycles,respectively). 相似文献
969.
由大肠杆菌以包涵体形式表达的一种抗内皮细胞生长工程蛋白(A nti-ang iogen ic agent,简称3A)经变性,Sephacry l S-100 HR柱复性,SP Sepharose FF离子交换吸附纯化,SephadexG-25脱盐,获得复性率为53.47%,HPLC纯度为92.52%的3A活性蛋白。以猪髋动脉内皮细胞为受检细胞,表明纯化蛋白具有抑制内皮细胞生长的特性。 相似文献
970.
用CH4、NH3和H2为反应气体,利用等离子体增强热丝化学气相沉积系统在沉积有碳膜的Si上制备了碳纳米尖端.用原子力显微镜表征了碳膜,结果表明碳膜是凸凹不平的膜,有许多凸起.在生长碳纳米尖端的过程中,由于既有含碳离子在凸起上的沉积,又有氢离子和含氮离子对凸起的刻蚀,根据有关离子沉积和溅射刻蚀的理论,理论分析了离子轰击碳膜凸起碳纳米尖端的形成. 相似文献