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991.
A new method using a column packed with graphene as adsorbent was developed for the preconcentration of trace amounts of cobalt (Co) and nickel (Ni) prior to their determinations by flame atomic absorption spectrometry. Several factors influencing the extraction efficiency of Co and Ni and their subsequent determinations, such as pH, amounts of the chelating agent, flow rates of sample and eluent solution, eluent type and its volume, breakthrough volume, and adsorption capacity were established. Under the optimum conditions, the calibration graphs were linear in the range of 4.0‐200.0 μg L?1 and 5.0‐200.0 μg L?1 with detection limits of 0.36 μg L?1 and 0.51 μg L?1 for Co and Ni, respectively. Good relative standard deviations for ten determinations of 100.0 μg L?1 of Co and Ni were 3.2 and 3.6%, respectively. The results for determination of Co and Ni in tap water, river water, sea water, vegetable and spiked samples have demonstrated the accuracy and applicability of the proposed method. To validate the proposed method, three certified reference materials of environment water (GSBZ 50030‐94 and GSB 07‐1186‐2000) and tomato leaf (GSBZ 51001‐94) were analyzed, and the determined values were in good agreement with the certified values. 相似文献
992.
Polymerizable Molecular Silsesquioxane Cage Armored Hybrid Microcapsules with In Situ Shell Functionalization 下载免费PDF全文
Dr. Yuxiu Xing Dr. Jun Peng Prof. Kai Xu Dr. Weihong Lin Dr. Shuxi Gao Yuanyuan Ren Xuefeng Gui Shengyuan Liang Prof. Mingcai Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2114-2126
We prepared core–shell polymer–silsesquioxane hybrid microcapsules from cage‐like methacryloxypropyl silsesquioxanes (CMSQs) and styrene (St). The presence of CMSQ can moderately reduce the interfacial tension between St and water and help to emulsify the monomer prior to polymerization. Dynamic light scattering (DLS) and TEM analysis demonstrated that uniform core–shell latex particles were achieved. The polymer latex particles were subsequently transformed into well‐defined hollow nanospheres by removing the polystyrene (PS) core with 1:1 ethanol/cyclohexane. High‐resolution TEM and nitrogen adsorption–desorption analysis showed that the final nanospheres possessed hollow cavities and had porous shells; the pore size was approximately 2–3 nm. The nanospheres exhibited large surface areas (up to 486 m2 g?1) and preferential adsorption, and they demonstrated the highest reported methylene blue adsorption capacity (95.1 mg g?1). Moreover, the uniform distribution of the methacryloyl moiety on the hollow nanospheres endowed them with more potential properties. These results could provide a new benchmark for preparing hollow microspheres by a facile one‐step template‐free method for various applications. 相似文献
993.
Wangdong Zeng Zhe Sun Tun Seng Herng Tho P. Gonalves Tullimilli Y. Gopalakrishna Kuo‐Wei Huang Jun Ding Jishan Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(30):8757-8761
The challenging synthesis of a laterally extended heptazethrene molecule, the super‐heptazethrene derivative SHZ‐CF3 , is reported. This molecule was prepared using a strategy involving a multiple selective intramolecular Friedel–Crafts alkylation followed by oxidative dehydrogenation. Compound SHZ‐CF3 exhibits an open‐shell singlet diradical ground state with a much larger diradical character compared with the heptazethrene derivatives. An intermediate dibenzo‐terrylene SHZ‐2H was also obtained during the synthesis. This study provides a new synthetic method to access large‐size quinoidal polycyclic hydrocarbons with unique physical properties. 相似文献
994.
Lysine acetylation is a dynamic and reversible modification, which has been proved to be a key posttranslational modification in cellular regulation. However, the low amounts of the acetylated proteins could hardly be detected before enrichment. In this study, for the first time, antibody‐immobilized magnetic carbonaceous microspheres were developed for selective enrichment of acetylated proteins and peptides. At first, standard proteins composed of acetylated bovine serum albumin, myoglobin, α‐casein and ovalbumin were used as model proteins to verify the enrichment efficiency. Then, the synthesized peptide was employed to confirm the selectivity of the method. Besides, the antibody‐immobilized magnetic particles were successfully applied to analyze mouse mitochondrial proteins. After database search, 29 acetylated sites in 26 proteins were identi?ed. 相似文献
995.
Jun Dai Lin Li LiPing He KangCheng Ruan HuiBin Lu KuiJuan Jin GuoZhen Yang 《中国科学:物理学 力学 天文学(英文版)》2014,57(11):2039-2042
In this work, we parallelly detected the specific binding between microarray targets including 12 different kinds of proteins and the probe solution containing five corresponding antibodies and quantitatively analyzed the interactions between CDH13 and solution phase anti-CDH13 at six different probe concentrations by oblique-incidence reflectivity difference (OIRD) method in label-free format. The detection sensitivity reached 10 ng/mL. The experimental results indicate that the OIRD method is a promising and competing technique not only in research work but also in clinic. 相似文献
996.
Covalent organic frameworks(COFs), as a class of crystalline porous materials with periodic lattices and porous structures, have received extensive attention in the fields of gas storage and separation, energy storage, catalysis and optoelectronics and so on. However, COFs are still in their infancy in the field of nuclear waste treatment, especially for sequestration of long-live problematic radionuclides, such as 99Tc. Battle of decontamination of pertechnetate(TcO4–), a main existence of 99Tc under aerobic environments, is far from finished. In this review, recent progresses of COFs and some relative materials in the sequestration of pertechnetate, and perspective on surmounting the unmet issues are elucidated. 相似文献
997.
Prof. Ying Wang Ping Xu Qiong Xie Qing‐Qing Ma Yan‐Hui Meng Dr. Zi‐Wen Wang Dr. Shaowei Zhang Prof. Dr. Xiao‐Jun Zhao Prof. Dr. Jun Chen Prof. Dr. Zhong‐Liang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(30):10459-10474
A bidentate ligand, 1‐{4‐[4‐(1H‐1,2,4‐triazol‐1‐yl)phenoxy]phenyl}‐1H‐1,2,4‐triazole (TPPT), has been designed and synthesized. By using TPPT as a building block for self‐assembly with Cd(NO3)2 ? 4 H2O and CdCl2 ? 10.5 H2O, novel 1D double‐chain {[Cd(TPPT)(NO3)2] ? 3 H2O}n ( 1 ) and 2D (4,4) layer [Cd(TPPT)Cl2(H2O)]n ( 2 ) have been constructed. When 1 was employed as a precursor and exposed to DMF or N,N′‐dimethylacetamide (DMAC), the crystals of 1 dissolved and reassembled into two types of brown block‐shaped crystals of 1D double chains: {[Cd(TPPT)2(NO3)2] ? DMF}n ( 1 a ) and {[Cd(TPPT)2(NO3)2] ? DMAC}n ( 1 b ). The anion‐exchange reactions of complex 2 have also been investigated. After gently stirring crystals of 2 in CHCl3/C2H5OH/H2O containing NaBr, NaI ? 2 H2O, or NaOAc ? 3 H2O, the crystals retained their crystalline appearances. A remarkable single crystal to single crystal transformation was observed and 1D double chains of {[Cd(TPPT)Br2] ? C2H5OH}n ( 2 a ) and {[Cd(TPPT)2I2] ? CHCl3}n ( 2 b ), and 1D single chains of [Cd(TPPT)(H2O)2(CH3COO)2]n ( 2 c ), can be obtained. Luminescent properties indicate that 1 shows excellent selectivity for Ca2+ and cyano complexes. To the best of our knowledge, this is the first example of a luminescent probe for Ca2+ based on triazole derivatives. 相似文献
998.
999.
讨论了完备化Witt代数的三类非有限阶化子代数的不可约非权模的实现,并利用它们的表示得到一些有趣的组合恒等式. 相似文献
1000.
利用“每课一题”这个教学环节从已有知识中提取基本原理,并应用于新知识的学习;提取学生的问题编制习题,让学生暴露产生问题的根源并从根本上解决。探讨了每课一题的必要性及其基本类型。 相似文献