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991.
Tetrahydrofuran (THF) hydrate was formed in bulk as well as in glass beads pack with a mean diameter of 3.0 mm by controlling the temperature under ambient pressure. Images of THF hydrate formation procedure were obtained using the magnetic resonance imaging (MRI) technique. The experiment results showed that MRI is an effective method for the detection of hydrate formation. Saturation of hydrate formed both in bulk and glass beads can be confirmed by intensity integration of MRI images. 相似文献
992.
Jian-Ping Zou Sheng-Lian Luo Ming-Jun Li Xin-Hua Tang Qiu-Ju Xing Qiang Peng Guo-Cong Guo 《Polyhedron》2010
A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C7H2NO5)·3H2O]n·nH2O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd2(C7H2NO5)3·4H2O]n·2nH2O (5) and [Ce(C7H2NO5)·1.5H2O]n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (44) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied. 相似文献
993.
ChengLian Feng YiPing Xu JinMiao Zha Qian Luo XiaoQuan Shan ZiJian Wang 《中国科学:化学(英文版)》2010,53(11):2379-2386
Decabromodiphenyl ether (BDE209) is poorly absorbed by mammals, and little information is available on the toxicokinetics of BDE209 and its metabolites in fish. In the present study, rainbow trout (Oncorhynchus mykiss) were administered to 100 ng/g and 500 ng/g body wet weight of BDE209 via a single intraperitoneal injection and parent BDE209 and its metabolites were sequentially monitored for 28 days. The results showed that toxicokinetic profiles of BDE209 could be described by the one-compartment model. In the higher dose group (500 ng/g wet weight), the calculated half-life (t 1/2) and elimination rate (k e) were 17.7 d and 0.039/d in the liver, and 100.3 d and 0.007/d in the muscle, respectively. Three major methoxylated brominated diphenyl ethers (MeO-BDEs) were detected with 2,2′,4,4′-tetrabromo-5-methoxydiphenyl ether (5-MeO-BDE47) being detected in all tissue samples. There was no significant temporal change of 5-MeO-BDE47 concentration in the muscle, whereas an exponential increase was observed in the liver. Therefore, the metabolism rate of BDE209 depended on the administered dose. BDE209 was hardly accumulated in the muscle of rainbow trout, while the liver was a primary metabolic organ. MeO-BDEs were formed via metabolism of BDE209, which probably played a significant role in fish toxicology as a potential indicator. 相似文献
994.
Li-Qiang Luo Qiu-Xia Li Ya-Ping Ding Ying Zhang Xia Shen 《Journal of Solid State Electrochemistry》2010,14(7):1311-1316
A glassy carbon electrode (GCE) modified with docosyltrimethylammonium chloride (DCTMACl) is used for simultaneous determination of dopamine (DA) and ascorbic acid (AA) using differential pulse voltammetry (DPV) technique in 0.10 mol·L?1 phosphate buffer solution of pH 5.0. The cationic surfactant DCTMACl modified film has a positive charge. DA exists as the positively charged species, whereas AA is the negatively charged one in the solution. Thus, at DCTMACl film-modified GCE, the oxidation peak potential of AA shifts toward less negative potential and the peak current of AA increases a little, while the oxidation peak potential of DA shifts toward more positive potential and peak current decreases greatly in comparison with that on bare electrode. The two anodic peaks are separated around 200 mV. Under optimal conditions, the catalytic peak currents obtained from DPV increase linearly with concentrations of DA and AA in the ranges of 1.0?×?10?5 to 1.0?×?10?3?mol·L?1. This electrode has good reproducibility, high stability in its voltammetric response, and low detection limit (micromolar) for both AA and DA. The modified electrode has been applied to the determination of DA and AA in injection. 相似文献
995.
以辛酸亚锡为催化剂, 1,4-丁二醇为引发剂, 制备出ε-己内酯/L-丙交酯共聚酯(PLCL). 以1-(3-二甲氨基丙基)-3-乙基碳二亚胺/N-羟基琥珀酰亚胺为缩合剂将肝素连接在PLCL两侧端基上. 采用 1H NMR技术测定了共聚酯端基的肝素化率; 用XPS分析了肝素化后聚酯中N和S含量, 利用甲苯胺蓝紫外分光光度计法测定了表面肝素含量, 并根据静态接触角测定结果讨论了材料表面的亲水性变化. 凝血酶原时间、凝血酶时间和部分凝血活酶时间测试数据表明, 肝素化后PLCL的抗凝血性能得到明显改善. 探索了该共聚酯进行电纺丝加工的可行性. 相似文献
996.
Peptide dendrimers are attractive synthetic polymers and have been widely used as a new generation of biomaterials in recent years. Peptide dendrimers, as well as general dendrimers, may be synthesized to reach nano sizes, and display well-defined architectures, highly-branched structures, high density of functional terminal groups, and controllable molecular weights. On the other hand, peptide dendrimers have properties similar to proteins and some special characteristics, such as good biocompatibility, water solubility and resistance to proteolytic digestion. Due to these advantages, peptide dendrimers have received considerable attention in biomedicine. This review focuses on the development of peptide dendrimers with emphasis on their applications both in diagnostics and in therapy. 相似文献
997.
Solvent-free reactions of aromatic aldehydes with three representative ketones, including acetophenone, acetone and cyclohexanone, have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K2CO3. It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst. Under the optimized experimental conditions, 1,2,3,4,5-pentasubstituted cyclohexanols, α,β-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields. Two Kostanecki’s triketones were separated, The composition and structure were affirmed by X-ray crystallographic analysis. 相似文献
998.
The pyrolysis of Pubescens over Ni/C catalyst was studied at 350 °C in H2 flow. The presence of Ni/C catalyst efficiently improved the degradation of raw materials, and produced bio-oil with high content of phenols but low contents of acetic acid, furfural and water. In the reaction, Ni/C catalyst plays the role of catalytic decomposition and catalytic hydrogenation. The existence of the carbon carrier favors the formation of active Ni in small sizes with more defects, which results in high catalytic activity of Ni in biomass decomposition and selective production of phenols. 相似文献
999.
LinHua Xie JianBin Lin XiaoMin Liu Wei Xue WeiXiong Zhang ShuXia Liu JiePeng Zhang XiaoMing Chen 《中国科学:化学(英文版)》2010,53(10):2144-2151
Solvothermal reactions of 1,3,5-benzenetricarboxylic acid (H3btc) with cadmium acetate or zinc acetate yielded two compounds formulated as (Me2NH2)[Cd(btc)]·DMA (1) (btc = 1,3,5-benzenetricarboxylate, DMA = N,N-dimethylacetamide) and (Me2NH2)[Zn(btc)]·DMF (2) (DMF = N,N-dimethylformamide). Both are 3-D frameworks with the rutile topology, which are constructed from six-connected dimeric metal cores and three-connected btc linkers. The solvent molecules and counter cations are located in the 1-D channels of the frameworks. A slight difference between the two compounds is the different connectivity modes of the metal atoms with the carboxylate groups of the ligands. However, this slight difference results in distinct flexibilities of the two frameworks. Variable-temperature powder X-ray diffraction studies revealed that the framework of 1 collapses when heated at 180 °C with loss of the guest species, but compound 2 undergoes two structural transformations below 380 °C. Thermogravimetry-infrared spectroscopy analysis for 2 showed that the two structural transformations are induced by separate losses of solvent molecules and counter cations, and that the dimethylammonium cations are eliminated as neutral dimethylamine molecules. IR spectroscopy demonstrated that the protons are transferred from the counter cations onto the uncoordinated carboxylate oxygen atoms on the channel walls. Sorption and proton conduction studies have also been performed for the compounds. 相似文献
1000.
Yangjun Xia Junfeng Tong Xia Ren Jie Luo Nong Wang Hongbing Wu Duowang Fan 《Polymer Science Series B》2010,52(9-10):614-620
Series of high molecular weight, readily soluble copolymers were synthesized by Suzuki palladium catalyzed coupling reaction from 9,9-dioctylfluorene and 2,3-dimethylnaphthopyrazine. The absorption, electrochemical and photoluminescence properties of the copolymers were studied. The external electrolu-minescence efficiencies in the devices of configuration indium-tin oxide/polyethylenedioxythiophene-polystyrene sulfonic acid/poly(fluorene-naphthopyrazine)/barium/aluminium varied with the copolymers composition, and the electroluminescence emission peaks of the copolymers were red-shifted from 530 nm to 584 nm as 2,3-dimethylnaphthopyrazine mole contents increasing from 0.5% to 30%. The best device performance was observed for devices fabricated with the copolymer of 2,3-dimethylnathphpyrazine 5% mole contents, showed maximum external quantum efficiency of 1.38% and electroluminescence peaks at around 537 nm. 相似文献