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1.
Yunchun Zhou Jianxin Geng Gao Li Enle Zhou Liang Chen Wanjin Zhang 《Journal of Polymer Science.Polymer Physics》2006,44(4):764-769
A series of crystals of phenyl‐capped tetraaniline in the leucoemeraldine oxidation state were obtained at different isothermal temperatures and were observed directly under transmission electron microscope. The crystals obtained at higher temperatures exhibit more perfect structures than those obtained at lower temperatures. Both the lamella thickness and the crystal size increase with crystallization temperature. The tetraaniline is apt to form larger scale crystals under lower degree of supercooling. However, their crystal structures keep steady with the crystallization temperature. The tetramer was found to adopt a monoclinic lattice with unit cell parameter of a = 13.93 Å, b = 8.82 Å, c = 23.20 Å, and β = 95.03°, as determined using electron diffraction tilting method combined with wide‐angle X‐ray diffraction experiment. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 764–769, 2006 相似文献
2.
We have developed a highly sensitive and selective sensor for lead(II) ions. A glassy carbon electrode was modified with Fe3O4 nanospheres and multi-walled carbon nanotubes, and this material was characterized by scanning electron microscopy and X-ray diffraction. The electrode displays good electrochemical activity toward Pb(II) and gives anodic and cathodic peaks with potentials at ?496 mV and ?638 mV (vs. Ag/AgCl) in pH?6.0 solution. The sensor exhibits a sensitive and fairly selective response to Pb(II) ion, with a linear range between 20 pM and 1.6 nM, and a detection limit as low as 6.0 pM (at a signal-to noise ratio of 3). The sensor was successfully applied to monitor Pb(II) in spiked water samples. Figure
A fast and sensitive Pb(II) electrochemical sensor has been fabricated by modifying Fe3O4 nanospheres and multi-walled carbon nanotubes onto the pretreated glassy carbon electrode. The electrode displays good electrochemical activity toward Pb(II). And a low detection limit of 6.0 pM, high sensitivity, good reproducibility and stability provide the Fe3O4/MWCNTs/GCE a definite candidate for monitoring lead ion in real samples. 相似文献
3.
大麦酯酶同工酶酶谱的聚类分析与遗传研究 总被引:4,自引:0,他引:4
采用聚丙烯酰胺凝胶电泳对主要产于我国不同地区的33份近缘野生大麦及其19份栽培大麦,以及它们间杂交的27个组合F1植株的叶片进行了酯酶同工酶分析.结果表明,52份材料可分成11个酶谱类型,聚类分析说明,同一亚种或同一变种,地理来源不同,酶谱表现不同.地理来源相同或相近的不同亚种或不同变种,酯酶同工酶酶谱一般表现出相同或相近.杂交组合F1中酶谱出现3种类型:偏亲本型,杂种型和互补型.其中以互补型为多.凡出现杂种酶带或互补酶带的植株,在穗长和株高上都表现出杂种优势的特征.对近缘野生大麦和栽培大麦的酶谱以及与地理距离的关系和酯酶同工酶在大麦中的应用进行了讨论. 相似文献
4.
Honghui Liu Yanling Chen Yunchun Liu Zhousheng Yang 《Journal of Solid State Electrochemistry》2013,17(10):2623-2631
This work described a novel sensor for detection of l -tryptophan (Trp) by electrodeposition of gold nanoparticles (AuNPs) onto the poly(alizarin red S) film pre-cast on a glassy carbon electrode (GCE). Alizarin red S (ARS) was deposited on the surface of the GCE by electropolymerization, and gold nanoparticles (AuNPs) were attached onto the poly(ARS) film by electrodeposition, forming an AuNPs–PARS nanocomposite film-modified GCE (AuNPs–PARS/GCE). Then electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were used to characterize modified electrodes. The Nyquist diagrams of EIS indicated that the PARS film and AuNPs were successfully immobilized on the surface of GCE, and the electron transfer resistance value of electrode changed efficiently. The SEM image showed that the immobilized AuNPs were spherical in shape. The AuNPs–PARS/GEC displayed excellent amperometric response for Trp. The amperometric responses have two linear ranges from 0.02 to 0.5 μM and 0.5 to 20.0 μM, with sensitivities of 1.63(±0.08) and 0.21(±0.01)?μAμM?1, respectively. Its detection limit was 6.7 nM at a signal-to-noise ratio of 3. The proposed method was applied to determine Trp. Figure
The procedure of the L-tryptophan sensor preparation 相似文献
5.
Qing Chen Yiting Ying Lijun Wang Zhiqi Guo Yunchun Zhou Dongmei Wang Chunxia Li 《无机化学与普通化学杂志》2020,646(9):437-443
Heterometallic MOFs, as an important branch of MOF materials, open up a new way to design and synthesize innovative MOF materials. Hence, it has positive significance for the development of MOF materials. By utilizing monofunctional linker CBDA [5,5'-(carbonylbis(azanediyl))-diisophthalic acid], a heterometallic MOF In/Gd-CBDA was obtained under “one-pot“ solvothermal method. The three-dimensional framework exhibits (3,4,6)-connected network belonging to a new topology. In addition, the synthetic conditions that affect the growth of crystal have been studied in detail. Numerous experiments led to the finding that the type and composition of solvents are very important for inducing the recognition of carboxylic acid groups at different positions coordination to diverse metals. Furthermore, the mechanism of this kind of heterometallic MOFs assembled by monofunctional linker under “one-pot” solvothermal method has been clarified, which is mainly related to the steric hindrance of functional groups and the properties of heterometals. Based on ideal adsorbed solution theory (IAST), In/Gd-CBDA shows the efficient selective gas adsorption, especially for equimolar mixtures of CO2/CH4 (13) and C3H8/CH4 (321). This work of heterometallic MOF material assembled by monofunctional linker under “one-pot” solvothermal method provides a new platform for the development of MOF materials in terms of enriching the topological family and broadening possibilities in advanced applications. 相似文献
6.
Lianbing Ren Yunchun LiuMingming Dong Zhen Liu 《Journal of chromatography. A》2009,1216(47):8421-8425
Boronate affinity chromatography is an important tool for specific isolation of cis-diol-containing compounds such as glycoproteins, RNA and carbohydrates. Boronate functionalized monolithic capillaries have been recently developed for specific capture of cis-diol-containing small biomolecules, but the apparent hydrophobicity of the columns prevents them from specific capture of glycoproteins. In this paper, a hydrophilic boronate affinity monolithic capillary was prepared by in situ free radical polymerization, using 4-vinylphenylboronic acid (VPBA) and N, N′-methylenebisacrylamide (MBAA) as functional monomer and cross-linker, respectively. The prepared poly(VPBA-co-MBAA) monolithic capillary exhibited uniform open channel network and high density of accessible boronic acid. Due to the utilization of hydrophilic cross-linker, the prepared column was hydrophilic, allowing for specific capture of glycoproteins. 相似文献
7.
Haijun Yang Fantian Zeng Yunchun Luo Chao Zheng Chongzhao Ran Jian Yang 《Molecules (Basel, Switzerland)》2022,27(12)
Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders, which is caused by multi-factors and characterized by two histopathological hallmarks: amyloid-β (Aβ) plaques and neurofibrillary tangles of Tau proteins. Thus, researchers have been devoting tremendous efforts to developing and designing new molecules for the early diagnosis of AD and curative purposes. Curcumin and its scaffold have fluorescent and photochemical properties. Mounting evidence showed that curcumin scaffold had neuroprotective effects on AD such as anti-amyloidogenic, anti-inflammatory, anti-oxidative and metal chelating. In this review, we summarized different curcumin derivatives and analyzed the in vitro and in vivo results in order to exhibit the applications in AD diagnosis, therapeutic monitoring and therapy. The analysis results showed that, although curcumin and its analogues have some disadvantages such as short wavelength and low bioavailability, these shortcomings can be conquered by modifying the structures. Curcumin scaffold still has the potential to be a multifunctional tool for AD research, including AD diagnosis and therapy. 相似文献
8.
Yunchun Wang Zhongyuan Bai Zengjun Wei Shengzhen Xu Xuegang Li Jianhong Li Xiufang Cao Changshui Chen 《Research on Chemical Intermediates》2011,37(8):1029-1039
Twenty-two novel N-nitro-N′-substituted phenyl-N-(2,6-dibromo-4-fluorophenyl)urea derivatives were designed and synthesized via a simple and convenient BTC ‘one-pot’ procedure
using DMAP as the catalyst. The structures of all newly synthesized compounds were confirmed by IR, 1H NMR, and elemental analysis, and a part has been identified by 13C NMR. The preliminary bioassay indicates that the target compounds possesses moderate herbicidal activity against Sorghum sudanense. However, some of the title compounds presented high plant growth regulating activity against rape. 相似文献
9.
Hu G Liu Y Zhao J Cui S Yang Z Zhang Y 《Bioelectrochemistry (Amsterdam, Netherlands)》2006,69(2):254-257
A L-cysteine (L-Cys) self-assembled modified gold electrode was used to detect dopamine (DA) by chronoamperometric method (CE) in the presence of ascorbic acid (AA). The defective limit is 2.0 x 10(-8) mol L(-1) (S/N=3). The proposed method was applied to detect DA in the samples with satisfied result. 相似文献
10.
Junliang Yang Ting Zhao Jijun Cui Leijing Liu Yunchun Zhou Gao Li Enle Zhou Xuesi Chen 《Journal of Polymer Science.Polymer Physics》2006,44(22):3215-3226
The confined crystallization behavior, melting behavior, and nonisothermal crystallization kinetics of the poly(ethylene glycol) block (PEG) in poly(L ‐lactide)–poly(ethylene glycol) (PLLA–PEG) diblock copolymers were investigated with wide‐angle X‐ray diffraction and differential scanning calorimetry. The analysis showed that the nonisothermal crystallization behavior changed from fitting the Ozawa equation and the Avrami equation modified by Jeziorny to deviating from them with the molecular weight of the poly(L ‐lactide) (PLLA) block increasing. This resulted from the gradual strengthening of the confined effect, which was imposed by the crystallization of the PLLA block. The nucleation mechanism of the PEG block of PLLA15000–PEG5000 at a larger degree of supercooling was different from that of PLLA2500–PEG5000, PLLA5000–PEG5000, and PEG5000 (the numbers after PEG and PLLA denote the molecular weights of the PEG and PLLA blocks, respectively). They were homogeneous nucleation and heterogeneous nucleation, respectively. The PLLA block bonded chemically with the PEG block and increased the crystallization activation energy, but it provided nucleating sites for the crystallization of the PEG block, and the crystallization rate rose when it was heterogeneous nucleation. The number of melting peaks was three and one for the PEG homopolymer and the PEG block of the diblock copolymers, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3215–3226, 2006 相似文献