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Applications of scanning probe microscopy in intrinsically conducting polymer research
YANG Tao, NIU Li, LI Zhuang, DONG Shaojun
Front. Chem. China. 2007, 2 (1): 1-5.
https://doi.org/10.1007/s11458-007-0001-0
The applications of scanning probe microscopy (SPM) in intrinsically conducting polymer research is briefly reviewed, including morphology observation, nanofabrication, microcosmic electrical property measurements, electrochemistry researches, in-situ measurements of film thickness change, and so on. At the same time, some important variations of SPM and the related techniques are briefly introduced. Finally, the future development of SPM in the study of intrinsically conducting polymers is prospected.
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Investigation on the Brill transition of polyamide 618
XIAO Dan, CUI Xiaowen, LI Weihua, YAN Deyue
Front. Chem. China. 2007, 2 (1): 6-12.
https://doi.org/10.1007/s11458-007-0002-z
The Brill transition of even even polyamide 618 was investigated using differential scanning calorimetry (DSC), temperature-dependent wide angle X-ray diffraction (WAXD) and Fourier transform infrared (FTIR). The X-ray diffraction results indicate that the melt-crystallized sample of polyamide 618 transforms from the triclinic unit cell to the pseudo-hexagonal phase in the range of 120 180?C. In this range, the thermograph of polyamide 618 presents a broad endothermal peak. From the FTIR spectra, it was found that during the transition process of polyamide 618, the intensity of the intra-sheet hydrogen bonds becomes weak. At the same time, the CH2 amide bonds twist, and the all-trans conformation of methylene sequences is disordered by inserting the gauche conformation. The CH2 segments are in a mobile state because of the enhanced stretching and twisting vibrations of the C CO and C N bonds.
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A new two-dimensional approach to quantitative prediction for collision cross-section of more than 110 singly protonated peptides by a novel moecular electronegativity-interaction vector through quantitative structure-spectrometry relationship studies
ZHOU Peng, MEI Hu, TIAN Feifei, WANG Jiaona, WU Shirong, LI Zhiliang
Front. Chem. China. 2007, 2 (1): 55-63.
https://doi.org/10.1007/s11458-007-0012-x
Based on two-dimensional topological characters, a novel method called molecular electronegativity-interaction vector (MEIV) is proposed to parameterize molecular structures. Applying MEIV into quantitative structure-spectrometry relationship studies on ion mobility spectrometry collision cross-sections of 113 singly proto nated peptides, three models were strictly obtained, with correlative coefficient r and leave-one-out cross-validation q of 0.983, 0.979, 0.981, 0.979 and 0.980, 0.978, respectively. Thus, the MEIV is confirmed to be potent to structural characteri zations and property predictions for organic and biologic molecules.
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Effect of carbon content on photocatalytic activity of C/TiO2 composite
LIN Li, ZHOU Yi, ZHU Yuexiang, XIE Youchang
Front. Chem. China. 2007, 2 (1): 64-69.
https://doi.org/10.1007/s11458-007-0013-9
A series of carbon-covered titania (CCT) were prepared via pyrolysis of sucrose highly dispersed on titania surface in flowing N2. The samples were characterized by XRD, BET, DTA-TG, UV Vis, and their photocatalytic properties were evaluated with two model pollutants, methylene blue (MB) and rhodamine B (RB), at room temperature. The effect of carbon content on photocatalytic activity of the C/TiO2 composite was investigated. It was found that the effect of carbon content is different for different pollutants or different light sources. For three tested samples, under UV illumination CCT01 has the highest activity for MB photocatalytic degradation, while in the case of RB, CCT02 is the most active photocatalyst. Under visible light illumination, CCT005 has the highest activity for both MB and RB photocatalytic degradation.
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Synthesis of bis-quaternary ammonium peroxotungstates (peroxomolybdates) and their catalytic activity in oxidation of alcohols by aqueous H2O2
SHI Xianying, WEI Junfa
Front. Chem. China. 2007, 2 (1): 70-73.
https://doi.org/10.1007/s11458-007-0014-8
Three kinds of bis-quaternary ammonium salts of peroxotungstate and peroxomolybdate, such as PhCH2N-(CH2)6NCH2Ph[W(O2)4] ° 2H2O, PhCH2N(CH2)6NCH2Ph[WO(O2)2(C2O4)] and PhCH2N(CH2)6NCH2Ph [MoO(O2)2(C2O4)], have been synthesized and characterized. Their catalytic activity in the oxidation of cyclohexanol and benzyl alcohol was investigated with only aqueous 30% hydrogen peroxide. The results show that the bis-quaternary ammonium peroxotungstates are excellent catalysts in the oxidation of benzyl alcohol and cyclohexanol under moderate conditions. However, the catalytic ability of bis-quaternary ammonium peroxomolybadates is relatively poor. The yields of benzyl acid, benzaldehyde, and cyclohexanone reached up to 93.0%, 93.6%, and 91.7%, respectively.
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Study on the interaction of trypsin with some DNAs and their analytical application by resonance Rayleigh scattering spectra
LI Shan, LIU Zhongfang, LIU Shaopu, KONG Ling
Front. Chem. China. 2007, 2 (1): 79-84.
https://doi.org/10.1007/s11458-007-0016-6
When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex, the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA, sDNA, and ctDNA are 0 2.3, 0 2.5, and 0 1.9 µg " mL-1, and the detection limits are 0.4, 0.7, and 1.1 ng " mL-1, respectively. In the determination of trypsin using hsDNA, the linear range is 0 30.0 µg " mL-1, and the detection limit is 39.0 ng°mL-1. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination of trace amounts of DNA was developed.
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Analytical comparison between unprepared and calcined magnetitum (Cishi)
LI Gang, JIN Tongshun, YOU Juan, WANG Lu, WU Qinan
Front. Chem. China. 2007, 2 (1): 85-88.
https://doi.org/10.1007/s11458-007-0017-5
The phases, chemical composition, surface appearance, crystal size, specific surface and thermal behavior of the unprepared and calcined forms of the mineral Magnetitum (Cishi), used as Chinese traditional medicine, were characterized by using X-ray powder diffraction, scan electron microscopy, inductively coupled plasma-atomic emission spectometry (ICP) and thermogravimetric (TG). The results indicated that after calcination the main phase Fe3O4 of the calcined Magnetitum (Duan Cishi) remained, while the Fe2O3 phase disappeared. The contents of the harmful chemical elements Cd and Pb were obviously reduced, while the crystal size increased from 24.5 to 35.7 nm and surface loosened. There were different TG curves for unprepared and calcined Magnetitum (Cishi) samples on heating. The former showed two weight-losing steps (at 367.9-422.1?C and 568.8-594.1?C), and the latter only one. These results might serve as a base for quality evaluation of Magnetitum (Cishi).
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Syntheses, spectra and crystal structures of a series of Mo/S(O) complexes containing oxalate ligand
ZHANG Baoli, XING Yongheng, ZHANG Yuanhong, BAI Fengying, XU Jiqing, YANG Guangdi, HUANG Xiaoying
Front. Chem. China. 2007, 2 (1): 93-97.
https://doi.org/10.1007/s11458-007-0019-3
Two Mo/S complexes: K6[Mo2O2S2(C2O4)2-(ClPO3)2]°H2O (1) and K6[Mo2O3S(C2O4)2(ClPO3)2]°3H2O (2) containing oxalate ligand were prepared by the reaction of (NH4)2MoS4 and potassium oxalate by adding a small amount of H3PO4 to adjust the value of pH in the system of methanol and water under an atmosphere of pure nitrogen at ambient temperature and characterized by means of elemental analysis, IR, and UV-Vis. Results of the analysis reveal that crystals of the complex 1 are orthorhombic, space group Pbcn, a=4.6370(2) nm, b=0.7549(2) nm, c=1.3888(4) nm, V=4.861(2) nm3, Z=8, M=945.49, Dc=2.58 g/cm3, μ=2.625 cm-1, R=0.063, and wR=0.075. In addition, their spectral properties were also discussed.
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21 articles
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