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991.
流动注射双安培法测定葛根素 总被引:1,自引:0,他引:1
利用不可逆电对的双安培检测原理,建立了流动注射双安培直接检测葛根素的电化学新方法.使用经过恒电位预阳极化处理的双铂电极,通过耦合葛根素在一支电极上的氧化和氧化铂在另一支电极上的还原两个不可逆电极过程,构成流动注射双安培检测体系.在外加电位差为0.2 V时,pH 8.94的碳酸钠-碳酸氢钠缓冲溶液中,测得氧化电流与葛根素浓度在6.0×10-6~1.0×10-3 mol/L范围内呈线性关系(r=0.997 4,n=8),检出限为1.0×10-6 mol/L.连续40次测定6.0 ×10-4 mol/L的葛根素,RSD=1.58%.用该方法对葛根素含量进行了测定,结果令人满意. 相似文献
992.
993.
石墨炉原子吸收直接测定蜂胶中铅 总被引:2,自引:0,他引:2
1引言蜂胶是蜜蜂从植物幼芽及树干上采集的树脂并混入蜜蜂上腭腺分泌物和蜂蜡等形成的具有粘性的天然胶状物质。蜂胶化学成分复杂,其中主要有黄酮类化合物、酚酸、酯、脂肪酸等化合物,由于蜂胶临床上具有显著抗菌、抗癌、提高机体免疫力等医疗保健作用,在国际上被誉为“紫黄金”。但蜂胶中重金属Pb一直为人们所关心,蜂胶中Pb可能来源于大气、提取及加工过程中。通常检测Pb要先对样品进行消化,本实验研究一种快速、简便和准确的测定蜂胶中Pb的方法,用无水乙醇溶解蜂胶直接用于石墨炉原子吸收测定并与国家标准方法比较测定,结果满意。2实验… 相似文献
994.
995.
咪唑啉纤维树脂分离富集/ICP-MS测定矿石中的痕量铂(Ⅳ) 总被引:5,自引:0,他引:5
本文提出了咪唑啉纤维树脂分离富集/ICP-MS测定矿石中痕量铂(Ⅳ)的方法。实验考察了影响咪唑啉纤维树脂分离富集痕量Pt(Ⅳ)的酸度、流速、洗脱液的组成、体积等因素,结果发现:在20%的王水介质中,Pt(Ⅳ)能定量吸附于树脂上并与大量其它金属分离;被吸附的Pt(Ⅳ)可用5%硫脲-1%HCl溶液定量洗脱,ICP-MS测定Pt(Ⅳ)的回收率为87%~102%。所建立的方法应用于硫镍矿管理样分析,其测定结果与推荐值吻合。 相似文献
996.
采用自组装的方法制备了纳米银粒子修饰金电极,并运用循环伏安法、交流阻抗谱探讨了该电极的电化学特性.研究了高氯酸二茂铁在该修饰电极上的直接电化学行为.实验结果表明,高氯酸二茂铁在该修饰电极上具有良好的电流响应.用示差脉冲法测定高氯酸二茂铁,其氧化峰电流与浓度在4.0×10-6~5.0×10-4 mol/L范围呈良好线性关系,线性方程为:Ip(μA)=0.0236c(μmol/L)-0.0975,线性相关系数为0.9982,检出限为2.3×10-7 mol/L(信噪比为3). 相似文献
997.
Jameel Ahmed Bhutto Lianfang Tian Qiliang Du Zhengzheng Sun Lubin Yu Muhammad Faizan Tahir 《Entropy (Basel, Switzerland)》2022,24(3)
Medical image fusion (MIF) has received painstaking attention due to its diverse medical applications in response to accurately diagnosing clinical images. Numerous MIF methods have been proposed to date, but the fused image suffers from poor contrast, non-uniform illumination, noise presence, and improper fusion strategies, resulting in an inadequate sparse representation of significant features. This paper proposes the morphological preprocessing method to address the non-uniform illumination and noise by the bottom-hat–top-hat strategy. Then, grey-principal component analysis (grey-PCA) is used to transform RGB images into gray images that can preserve detailed features. After that, the local shift-invariant shearlet transform (LSIST) method decomposes the images into the low-pass (LP) and high-pass (HP) sub-bands, efficiently restoring all significant characteristics in various scales and directions. The HP sub-bands are fed to two branches of the Siamese convolutional neural network (CNN) by process of feature detection, initial segmentation, and consistency verification to effectively capture smooth edges, and textures. While the LP sub-bands are fused by employing local energy fusion using the averaging and selection mode to restore the energy information. The proposed method is validated by subjective and objective quality assessments. The subjective evaluation is conducted by a user case study in which twelve field specialists verified the superiority of the proposed method based on precise details, image contrast, noise in the fused image, and no loss of information. The supremacy of the proposed method is further justified by obtaining 0.6836 to 0.8794, 0.5234 to 0.6710, and 3.8501 to 8.7937 gain for , CRR, and AG and noise reduction from 0.3397 to 0.1209 over other methods for objective parameters. 相似文献
998.
Xiaoxiao Zheng Rongli Zhai Zihao Zhang Baoqing Zhang Jiangwei Liu Aamir Razaq Muhammad Ashfaq Ahmad Rizwan Raza Muhammad Saleem Syed Rizwan Syed Hassan Mujtaba Jafri Hu Li Raffaello Papadakis 《Molecules (Basel, Switzerland)》2022,27(6)
Composite materials and their applications constitute a hot field of research nowadays due to the fact that they comprise a combination of the unique properties of each component of which they consist. Very often, they exhibit better performance and properties compared to their combined building blocks. Graphene oxide (GO), as the most widely used derivative of graphene, has attracted widespread attention because of its excellent properties. Abundant oxygen-containing functional groups on GO can provide various reactive sites for chemical modification or functionalization of GO, which in turn can be used to develop novel GO-based composites. This review outlines the most recent advances in the field of novel dyes and pigments encompassing GO as a key ingredient or as an important cofactor. The interactions of graphene with other materials/compounds are highlighted. The special structure and unique properties of GO have a great effect on the performance of fabricated hybrid dyes and pigments by enhancing the color performance of dyes, the anticorrosion properties of pigments, the viscosity and rheology of inks, etc., which further expands the applications of dyes and pigments in dyeing, optical elements, solar-thermal energy storage, sensing, coatings, and microelectronics devices. Finally, challenges in the current development as well as the future prospects of GO-based dyes and pigments are also discussed. This review provides a reference for the further exploration of novel dyes and pigments. 相似文献
999.
3,5-二氰基-2,4,6-三甲基吡啶在新型光电功能材料的合成中有重要的应用价值.本文在CCl4中光照1,4-二氢-3,5-二氰基-2,4,6-三甲基吡啶,高产率地合成了3,5-二氰基-2,4,6-三甲基吡啶. 相似文献
1000.