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Function of the Hydrogen-bonding Network Between the Y-S-R Motif and the Heme Propionate Groups in sGC-HNOX Domain ZHANG Yue-Bin, CHENG Ying-Kun, Lü Ming, ZHANG Hua-Li, LI Zheng-Qiang* Chem. J. Chinese Universities    2010, 31 (5): 1039-1044.   Abstract （13373）      PDF（pc） （856KB）（454）       Knowledge map    Save Molecular dynamics methods were implemented to investigate the functions of hydrogen-bonding network between the conserved Y-S-R motif and the heme propionate groups in sGC-HNOX domain. The RMSD analysis reveals that the hydrogen-bonding network can stabilize the conformation of sGC-HNOX domain conspicuously during our simulation. The secondary structure, radius of gyration and solvent-accessible surface area of sGC-HNOX domain are not disturbed by the restraint hydrogen-bonding network. The principal component analysis on trajectory data and the heme configuration analysis indicate that the essential function of hydrogen-bonding network is to stabilize the binding of 4-E motif to 7-H motif, which is related to the structu-ral integrity of sGC-HNOX domain. Reference | Related Articles | Metrics Cited: Baidu(9)

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Structure-Property Investigation on TDNAZ·HNO3 and DNAZ·HCl GAO Rong1,2, MA Hai-Xia1*, YAN Biao1, SONG Ji-Rong1, WANG Ying-Hui1 Chem. J. Chinese Universities    Abstract （11151）      PDF（pc） （482KB）（440）       Knowledge map    Save 1,3,3-Trinitroazetidine(TNAZ) is one of famous insensitive and high energetic materials, which can be synthesized by 3,3-dinitroazetidine(DNAZ). N-Tertiarybutyl-3,3-dinitroazetidine nitrate(TDNAZ·HNO3) and 3,3-dinitroazetidine hydrochloride(DNAZ·HCl) were synthesized during the process of synthesizing DNAZ. Single crystals suitable for X-ray measurement were obtained. TDNAZ·HNO3 crystallizes in the orthorhombic system, space group Pnma with unit cell parameters a=1.2697(3) nm, b=0.8179(2) nm, c=1.1621(3) nm, V=1.2067 nm3 , Z=4. DNAZ·HCl crystallizes in the orthorhombic system, space group Cmc21 with unit cell parameters a=0.6681(2) nm, b=1.0441(2) nm, c=0.9971(2) nm, V=0.6955 nm3, Z=4. The Density-Functional Theory(DFT) method was used to calculate the geometry and frequencies of the two intermediates. The geometry, Hishfeld charges of atoms, Mayer bond orders, frontier orbital energy and the main atomic orbital percentage were calculated. The corresponding reaction mechanism was explained based on the molecular and electronic structural information. The thermal stability was also compared by their thermal behavior. Related Articles | Metrics

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Influence of Zr Content on Stability of (CeMn)1-xZrxO2 Catalysts for Catalytic Combustion of Diesel Soot ZHU Yi, YAN Chao-Yang, ZHAO Ming, LI Xiao-Shuang, GONG Mao-Chu, CHEN Yao-Qiang Chem. J. Chinese Universities    2013, 34 (2): 394-400.   DOI: 10.7503/cjcu20120391 Abstract （10895）      PDF（pc） （1002KB）（729）       Knowledge map    Save (CeMn)1-xZrxO2 catalysts were prepared by co-precipitation, where 0≤x≤0.3 and the molar ratio of CeO2 to MnO2 was 6: 4. The catalytic activities of these catalysts for the catalytic combustion of diesel soot were investigated. The catalysts were further characterized by a series of characterization methods. The results of X-ray diffraction(XRD) and low temperature nitrogen adsorption-desorption measurements indicated that the addition of ZrO2 improved the structure properties and textural properties of aged catalysts. When x≥0.2, the catalysts exhibited optimum structure properties, while improved textural properties could be observed for the catalysts with x≥0.1. The results of H2-temperature programmed reduction(H2-TPR) measurements revealed that, among the ZrO2-doped aged catalysts, the one with x=0.2 exhibited the best low-temperature reduction ability. The results of O2-temperature programmed desorption(O2-TPD) measurements suggested that the adding of ZrO2 increased the anion vacant sites on the surface of the catalysts and improved the catalyst's ability to adsorb and activate O2. The results of catalytic activities of these catalysts discolsed that Tm(Tm is the temperature at which the maximal mass loss can be observed in the combustion process of soot) of the fresh catalysts decreased by about 270 ℃. After aged, the adding of ZrO2 increased the stability. When x=0.2, the catalyst exhibited excellent thermal resistance performance, the gap of Tm before and after aging was only 6 ℃. These catalysts suggested potential application in diesel soot catalytic combustion. Related Articles | Metrics

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Studies on Polycondensation of BHEN QIAO Qian, HAN Yi-Jun, CHEN Yan-Mo, LIU Gui-Yun, ZHAOYa-Juan, LIU Ruo-Wang Chem. J. Chinese Universities    2006, 27 (2): 386-388.   Abstract （10675）      PDF（pc） （195KB）（355）       Knowledge map    Save Abstract BHEN intermediate was synthesize via transesterification between NDC and EG and the effect of processing conditions on synthesis of PEN was studied via BHEN polycondensation and by using orthogonal experiment method. Zinc acetate was optimized as the catalyst and steric phenol WZF1010 as the antioxidant and the optimum processing conditions for BHEN polycondensation are as follows: reaction temperature 568 K, the catalyst concentration is about 4×10-4 mol pet one mol of BHEN, reaction time 180 minutes and the antioxidant concentration is about 1×10-5 mol pet one mol of BHEN. Related Articles | Metrics Cited: Baidu(3)

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Proton Transfer of 2-(2-Amino-3-pyridyl)-benzimidazole Under the Inclusion Interaction with Cucurbit[8]uril YI Ping-Gui, YANG Xi-Chun, YU Xian-Yong, LIU Zheng-Jun, LIU Jin, WANG Zhao-Xu, LI Xiao-Fang Chem. J. Chinese Universities    2012, 33 (12): 2657-2662.   DOI: 10.7503/cjcu20120582 Abstract （10627）      PDF（pc） （1445KB）（653）       Knowledge map    Save The inclusion interaction of 2-(2-amino-3-pyridyl)-benzimidazole(2-A3PyBI) with cucurbit[8]uril(CB8) and the effect of the interaction on the proton transfer of 2-A3PyBI were studied via fluorescence emission spectroscopy, UV absorption spectroscopy and 1H NMR. The results show that 2-A3PyBI has a dual emission fluorescence which corresponds to its proton transfer tautomers. The fluorescence titration results at selected pH value indicate that the interaction ratio is 1:2 and the encapsulation of 2-A3PyBI into CB8 cavity enhances the excited-state intramolecular proton transfer process. The 1H NMR titration results, which the benzene ring signal upward but no obviously change of the pyridine ring was observed in DCl/D2O, indicate that the benzene ring of 2-A3PyBI entrapped into the CB8 cavity with the pyridine ring outside the cavity. Related Articles | Metrics Cited: Baidu(4)

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Effects of Signal Peptide on the Secretory Expression of Multifunctional Amylase OPMA and Its Catalytic Activity LI Yan-Fei, ZHANG Jin-Xiang, GU Yan-Qin, HAO Qian, CAO Hao, ZHANG Ying-Jiu Chem. J. Chinese Universities    2013, 34 (10): 2334-2339.   DOI: 10.7503/cjcu20130337 Abstract （10599）      PDF（pc） （2577KB）（765）       Knowledge map    Save The recombinant expression vectors pMA5-OPMA-SN and pMA5-OPMA-SG were constructed by fusing the gene encoding the signal peptide(S) of amyE from Bacillus subtilis 168 with the gene encoding the multifunctional amylases OPMA-N or OPMA-G, and the high-level secretory expression of OPMA-N and OPMA-G were achieved by Bacillus subtilis 168. SDS-PAGE analysis showed that the introduction of the signal peptide was indeed possible to improve the secretion of heterologous protein, and the secretory yields of OPMA-SN or OPMA-SG(53% or 67%) were obviously higher than those of OPMA-N or OPMA-G(45% or 58%), but the signal peptide could not be effectively removed after secretion. The activity analysis demonstrated that the levels of OPMA-SN and OPMA-N activities(5.17 and 4.57 U/mg) were consistent with their secretory yields, but it was not the case for OPMA-SG(4.50 U/mg) and OPMA-G(4.65 U/mg), there was a negative correlation between the activity levels and secretory yields of for OPMA-SG and OPMA-G. The spatial conformation of OPMA-SN and OPMA-SG molecules proved that the presence of the signal peptide at the N terminus of OPMA-N or OPMA-G could not affect the conformation of the catalytic centre in OPMA-N, but affected that in OPMA-SG and resulted in the decrease of OPMA-SG's catalytic activity. These findings could provide important guidance on signal peptide application for secretory expression of heterologous proteins in Bacillus subtilis, and for the structure and function of the target protein. Reference | Related Articles | Metrics

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Studies on Regioselective Catalyzed Modification of Poly(methylhydrosiloxane) Using Quaternized Poly(amidoamine) Dendrimer-Encapsulated RuRh Bimetallic Nanoparticles PENG Xiao-Hong*, PAN Qin-Min*, Garry L. Rempel, PENG Xiao-Chun Chem. J. Chinese Universities    2009, 30 (4): 813-817.   Abstract （10311）      PDF（pc） （515KB）（276）       Knowledge map    Save Partially quaternized fifth-generation poly(amidoamine) dendrimer-encapsulated RuRh bimetallic nanoparticles(DENs) were prepared via co-complexation method. The formation of DENs, the particle size and distribution of RuRh bimetallic nanoparticles were investigated by UV-Vis absorption spectroscopy, laser scattering analysis, and TEM. The results of FTIR and NMR spectroanalyses show that a high efficiency of regioselective hydrosilation modification of poly(methylhydrosiloxane) is achieved with the RuRh bimetallic DENs catalysts. Reference | Related Articles | Metrics

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Synthesis of Amphiphilic Block Codendrimers Gx-PBE-b-Gx-PMPA(OH)x2 and Study on Temperature Dependence of Multiple Hydrogen Bonds YUAN Fei, LI Qiu-Yue, WANG Wei* Chem. J. Chinese Universities    2011, 32 (11): 2667-2673.   Abstract （9961）      PDF（pc） （847KB）（274）       Knowledge map    Save Block codendrimers Gx-PBE-b-Gx-PMPA were synthesized through a coupling reaction between Gx-PBE dendrons and Gx-PMPA dendrons(x=1, 2, 3). Amphiphlic block codendrimers Gx-PBE-b-Gx-PMPA(OH)x2 were further prepared through removing acetonide protecting groups on the periphery of the Gx-PMPA blocks. Their chemical structures were characterized by 1H NMR and 13C NMR spectroscopies, MALDI-TOF(or FD) mass spectroscopy and FTIR spectroscopy. Meanwhile, FTIR spectrometer equipped with a heating stage was used to study the change of the hydrogen bonds in-between hydroxyl groups with increasing temperature. A widened transition region with increasing dendron generation was found. This result can indicate that with increasing dendron generation the ability of forming intermolecular hydrogen bonds decrease due to the three-dimensional structure of higher generation dendron. Related Articles | Metrics Cited: Baidu(1)

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Theoretical Studies on the Effect of Fapy-G on Base Pair Hydrogen Bond Complexes† LIU Cui, ZHANG Qianhui, GONG Lidong, LU Linan, YANG Zhongzhi Chem. J. Chinese Universities    2014, 35 (12): 2645-2653.   DOI: 10.7503/cjcu20140510 Abstract （9915）   HTML （4）    PDF（pc） （4405KB）（628）       Knowledge map    Save One of the primary oxidative DNA damage is 2,6-diamino-4-hydroxy-5-formamido pyrimidine, named Fapy-guanine(Fapy-G), which is the product of guanine oxidized at C8. The properties of 20 oxidative base pairs which contains Fapy-G were investigated via quantum chemistry methods. All model molecular structures were optimized with B3LYP/6-31+G* method and the frequency calculations were carried out to confirm that all the structures obtains were geometrically stable. The energies were determined at the MP2/aug-cc-pVDZ level with BSSE corrections. The calculation results show that N7, N9 became hydrogen bond donor from accepter. Natural atomic charge of N7, N9 and O6 get more negative. The ability of O6 as H-bond donor enhanced. The bond lengths of C5—N7 and N7—C8 were increased by 0.0045 and 0.0063 nm, C4—N9 was decreased by 0.0015 nm. Compared with bases monomers, natural atomic charge of proton acceptors in hydrogen bond complexes increased by 0.05 e averagely, which is 8% of the original charge; natural atomic charges for proton donors have a decrease of 0.02 e, which is 4% of the original charge. Compared with Fapy-G, when the N atom in Fapy-G six-membered ring was formed H-bond, the ring breathing and N-para-C vibrational frequencies were blue shifts. The vibrational frequencies were related to H-bond red shifts in all the base pairs. NH…N is stronger than NH…O in all the base pairs and in NH…N the hydrogen bond energy of donor N atom in six-membered ring are bigger than donor N atom in NH2 or open-ring. When Fapy-G pairs with base A, the binding energy region order is 1>2>4>3. When Fapy-G pairs with base T(R), the binding energy region order is 3=4>1>2. In water solvent, the binding energies of Fapy-G pairs with base C reduced to 41.84—58.58 kJ/mol, and the order of the binding energy was changed. Table and Figures | Reference | Related Articles | Metrics Cited: Baidu(1)

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Synthesis of Nanometer Amino Acid Heteropoly Charge-transfer Complex (HPhe)3PMo12O40·2H2O by One Step Solid State Reaction at Room Temperature WANG Rui-Ying, LIU Lang, JIA Dian-Zeng, LUO Jian-Min, FAN Zhao-Tian Chem. J. Chinese Universities    2004, 25 (12): 2208-2211.   Abstract （9676）      PDF（pc） （208KB）（366）       Knowledge map    Save A nanometer amino acid heteropoly charge-transfer complex was synthesized from Keggin structure phosphomolybdic acid (H3PMo12O40·13H2O) and phenylalanine(Phe) by one step solid state reaction at room temperature. The title compound was characterized by means of elemental analysis, IR, XRD, TEM, UV and CV. The results indicate that the sizes of the compound are in the range of 30-40 nm. The heteropoly anion still remains its Keggin structure in the product molecules. A sizeable electron-transfer interaction occurs between phosphomolybdic acid and phenylalanine. The electrochemical behavior of the compound in 1 mol/L H2SO4 shows that three redox waves correspond to three two-electron processes attributing to the reduction of PMo12O403- . Solid state reaction at room temperature is a convenient synthetic method for nanomaterials and may provide a new path to synthesize nanometer amino acid heteropoly complex. Reference | Related Articles | Metrics

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Effect of Atmosphere on the Growth of MnCr2O4 Spinel Nanowires LUO Li-Jie, TONG Zhang-Fa, MO Li-Bin, LIANG Zhong-Yuan, CHEN Yong-Jun* Chem. J. Chinese Universities    2009, 30 (4): 647-650.   Abstract （9662）      PDF（pc） （537KB）（425）       Knowledge map    Save MnCr2O4 spinel single-crystalline nanowires were synthesized by heating commercial stainless steel foil under a reducing atmosphere. The hydrogen content in the atmosphere has important influence on the yield and morphology of the grown nanowires. It was found that the reducing atmosphere plays a key role in the nanowire growth. In the reducing atmosphere, the Mn and Cr elements in the stainless steel could be selectively oxidized because of their higher affinity for oxygen than the Fe and Ni elements. The Fe and Ni elements in the stainless steel, however, acted as the catalyst for the vapor-liquid-solid(VLS) growth of the MnCr2O4 nanowires. Reference | Related Articles | Metrics Cited: Baidu(3) Baidu(3)

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SnAl4- and PbAl4-: Two New Planar Tetra-coordinate Molecule GAO Si-Meng, HE Hai-Peng, DING Yi-Hong Chem. J. Chinese Universities    2013, 34 (1): 185-191.   DOI: 10.7503/cjcu20120248 Abstract （9570）      PDF（pc） （4505KB）（431）       Knowledge map    Save The isomerization potential energy surface of XAl4-(X=Sn, Pb) at the CCSD(T)/aug-cc-pVTZ&CEP-121G//B3LYP/6-311+G(d)&LANL2DZ level(CEP-121G and LANL2DZ for Sn, Pb only) was constructed by means of the global isomeric search method. The results show that for X=Si/Ge, the planar tetra-coordinate X structure is the global isomer. Yet, for X=Sn/Pb, in addition to the planar tetra-coordinate X isomer, a "pyramidal" structure lies almost isoenergetic. Morevoer, from X=Si/Ge to X=Sn/Pb, the potential energy surface becomes smoother. The present work not only provides new clues to the 17 valence electron rule in the planar chemistry, but demonstrates that the doping at the X-site would have significant influence on the stability of the planar tetra-coordinate structure. Related Articles | Metrics

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Influence of DOPC, DOPE and Ceramide on the Organization of Sphingomyelin/Cholesterol Bilayers HAO Chang-Chun, SUN Run-Guang*, ZHANG Jing Chem. J. Chinese Universities    2009, 30 (5): 913-918.   Abstract （9433）      PDF（pc） （544KB）（389）       Knowledge map    Save Lipid rafts are of a dynamic microdomain structure found in recent years, enriched in signal molecules. The change of structure and function of lipid rafts can result in many diseases. LB technique and atomic force microscopy were used to study the effect of 1,2-dioleoy-sn-glycero-3-phosphocholine(DOPC), 1,2-dioleoy-sn-glycero-3-phosphoethanolamine(DOPE) and ceramide on the structure of sphingomyelin(SM)/Cholesterol LB bilayers. We found that each bilayer of lipid mixtures took on uniform distribution bilayer structure when the surface pressure was low. When increasing the surface pressure, great changes were taken place on the bilayers: (1) The bilayers composed of SM/Chol appeared uniform liquid-ordered microdomains structure, with coverage of 80% of mica. (2) In SM/Chol/DOPC bilayers, the liquid-ordered microdomains formed by SM/Chol floated onto the fluid-disordered small DOPC granule, about 30% coverage. (3) When adding DOPE to SM/Chol, the bilayers had changed obviously, meanwhile liquid-disordered, liquid-ordered and gel phases coexisted on the mica. (4) The Ceramide induced the bilayers of SM/Chol rearrangement, the lipids of bilayers occurred flip-flop to form vesicle structure. At the higher surface pressure, all the systems could form specific platform structure. The bond capabilities of molecular groups play an important role in forming structure. Reference | Related Articles | Metrics

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Preparation of Carbon Supported PdPb Catalysts and Its Electrocatalytic Performance in Oxidation of Formic Acid GENG Xiao-Wei, WU Bing, GAO Ying Chem. J. Chinese Universities    2012, 33 (09): 2025-2029.   DOI: 10.3969/j.issn.0251-0790.2012.09.026 Abstract （9316）      PDF（pc） （981KB）（830）       Knowledge map    Save The carbon supported PdPb catalysts with different Pd and Pb mass ratios were prepared in the aqueous solution by a chemical reduction method. The studies show that the PdPb/C catalysts can promote the activity for formic acid electrooxidation and change the reaction mechanism. As the catalysts with small ratio of Pb, it can enhance the dispersion of active component and largely enhance the electrocatalytic activity of the catalysts toward the electrooxidation of formic acid. When the mass ratio of Pd and Pb is 8: 1, the catalyst shows the highest catalytic activity for formic acid oxidation, and the peak current density increases 180% compared to that on Pd/C. When the mass ratio of Pd to Pb is 2: 1, the catalyst shows the best behavior of stability. Reference | Related Articles | Metrics Cited: Baidu(3)

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Synthesis of Precursors ZrMo2-xWxO7(OH,Cl)2·2H2O and Cubic ZrMo2-xWxO8 Thermal Contraction Compounds by Acidic GUO Shu-Rong1, DENG Xue-Bin2, Ma Hui3, ZHAO Xin-Hua2 Chem. J. Chinese Universities    Abstract （9091）      PDF（pc） （742KB）（675）       Knowledge map    Save The precursors, ZrW2O7(OH,Cl)2·2H2O(x=0 ,0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8), of cubic ZrMo2-xWxO8 were synthesized successfully by acidic steam hydrothermal no-wash(ASH-NW) method, in succession the preparation of cubic ZrMo2-xWxO8 were made from the precursors. The relative XRD intensity was proposed to characterize the saturated order degree(η'T) of the metastable order-disorder phases and the correlation was found that the n(Mo)/n(W) ratio is reduced, the order degree(η'T) is risen under the preparation condition. An argumentation was presented to discuss the effect of raw materials on the morphology of the intermediate phase as well as the products. Furthermore, the outline of the micro-process in which the ammonium salt was used as the raw material during the preparation of precursor was discussed. Related Articles | Metrics

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Determination of Free Aliphatic Amines in Environmental Water by EASC Derivatization and Identification with LC-APCI-MS ZHAO Huai-Xin, SUN Xue-Jun, SUN Zhi-Wei, YAN Tao, ZHANG Zai-Qing, LIU Qin-Ze, SUO You-Rui, LI Yu-Lin, YOU Jin-Mao* Chem. J. Chinese Universities    2009, 30 (4): 675-681.   Abstract （9049）      PDF（pc） （555KB）（392）       Knowledge map    Save On a reversed-phase Hypersil BDS C18(4.6 mm×200 mm, 10 μm i.d.) column, 12 aliphatic amines were derivatized using 10-ethyl-9-oxo-9,10-dihydroacridine-2-sulfonyl chloride(EASC) as a new pre-column derivatization reagent. The complete baseline resolution was obtained in conjunction with a gradient elution with acetonitrile/H2O as mobile phase within 20 min. The optimum excitation and emission wavelengths were at λex/λem=270 nm/430 nm. Comparing with the widely used Dansyl-Cl, EASC has stronger photoluminescence characteristics(ultraviolet and fluorescence): UVEASC/UVDansyl-Cl=3.2(UV: ultraviolet absorption intensity); I(EASC)/I(Dansyl-Cl)=30.0∶1—105.4∶1(I: relative fluorescence intensity); fluorescence quantum yield: Φf(EASC)/Φf(Dansyl-Cl)=43.0∶1. Fast and accurate quantitative analysis of aliphatic amines with fluorescence and corresponding post-column ion trap mass spectrometry(LC-APCI-MS) were obtained. EASC-amines exhibited stronger mass spectrometric sensitivity relative to that of dansyl-amine derivatives: MSEASC/MSDansyl-Cl=1.6∶1—6.2∶1 times(MS: relative intensity of ion current). The established method for the determination of aliphatic amines in environmental water samples exhibited good reproducibility and recovery. Excellent linear responses were observed with the correlation coefficients >0.9995. The detection limits(at signal-to-noise of 3∶1) were at levels of 4.0—12.7 fmol. Related Articles | Metrics Cited: Baidu(7)

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Electrochemical Behavior of Mn(Ⅱ) in the Melt LiCl-KCl-MgCl2-MnCl2 CHEN Li-Jun, ZHANG Mi-Lin, HAN Wei, YAN Yong-De, CAO Peng Chem. J. Chinese Universities    2012, 33 (02): 327-330.   DOI: 10.3969/j.issn.0251-0790.2012.02.020 Abstract （8721）      PDF（pc） （900KB）（650）       Knowledge map    Save The reduction of Mn(Ⅱ) on a molybdenum electrode in the melt LiCl-KCl-MgCl2-MnCl2 at 898 K and the conditions of the co-deposition of Mg-Li-Mn alloys were investigated. Cyclic voltammetry and chronopotentiometry show that the reductions of Mn(Ⅱ), Mg(Ⅱ) and Li(Ⅰ) start at -1.14, -1.78 and -2.19 V, respectively. And the underpotential deposition of magnesium on pre-deposited manganese leads to the formation of a liquid Mg-Mn solution, then a liquid Mg-Li-Mn solution forms for the succeeding underpotential deposition of lithium on pre-deposited Mg-Mn. The diffusion coefficient of Mn(Ⅱ) in the melts was also calculated with different methods, which was about 10-5 cm2/s. The analysis of X-ray diffraction indicats that there are three phases(β-Li, α-Mg and Mn) in the Mg-Li-Mn alloy. Reference | Related Articles | Metrics

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Synthesis and Properties of Novel Porphyrin Modified by Pyridine Derivative LIU Mei, YAN Wei-Wei, ZANG Na, RUAN Wen-Juan*, ZHU Zhi-Ang Chem. J. Chinese Universities    2009, 30 (8): 1501-1508.   Abstract （8670）      PDF（pc） （709KB）（515）       Knowledge map    Save A new kind of tailed zinc porphyrin modified by pyridine derivative(o-PyOC6H12OTPPZn) was synthesized and characterized by elementary analysis, UV-Vis, 1H NMR, IR, and MS spectra. The axial coordination reaction was studied between o-PyOC6H12OTPPZn and pyridine derivatives by UV-Vis spectra titration. The binding constants decreased in the order of K(4-MePy)>K(Py)>K(3-MePy)>K(2,4,6-triMePy)>K(2-MePy) for pyridine derivatives. The results show that the capability of axial ligands decreased in the sequence of 4-MePy>Py>3-MePy>2,4,6-triMePy>2-MePy. Moreover, the lowest energy conformations of the complexes between the zinc porphyrin and pyridine derivatives were obtained by simulated annealing and the results explained the experiment results well. The nonlinear optical property of o-PyOC6H12OTPPZn was investigated by Z-scan experiment. Reverse saturated absorption of the compound was observed. Reference | Related Articles | Metrics Cited: Baidu(2)

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Three-photon Absorption and Upconversion Fluorescence of Bis-, Quadri-, Octu-branched Symmetrical Oxadiazole Derivatives QIAN Ying*, ZHU Xiao-Qin, JI Yan, HUANG Wei, Lü Chang-Gui, CUI Yi-Ping Chem. J. Chinese Universities    2010, 31 (4): 703-707.   Abstract （8393）      PDF（pc） （375KB）（336）       Knowledge map    Save The three-photon absorption and the three-photon-excited fluorescence spectra of three symmetrical oxadiazole derivatives, 4-[N,N-bis(4-{4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]styryl}phenyl)amino]benzaldehyde(Bis-oxa), 2,5-bis(4-{2-N,N-bis[4-(2-{4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]-phenyl}-vinyl)phenyl]aminostyryl}phenyl)-1,3,4-oxadiazole(Quadri-oxa) and 2,5-bis(4-{2-N,N-bis[4-(2-{3,5-di-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]phenyl}-1-ethenyl-)phenyl]aminostyryl}phenyl)-1,3,4-oxadiazole(Octu-oxa) were measured by nonlinear transmission method using a femtosecond Ti∶sapphire laser. Their three-photon absorption coefficients of 1260 nm were 5.0×10-5, 10.0×10-5 and 10.0×10-5 cm3/GW2, respectively. Pumped by a femtosecond laser at 1260 nm, strong upconversion fluorescence with the central wavelength at 533 nm(Bis-oxa), 544 nm(Quadri-oxa)and 551 nm(Octu-oxa) in the solution of CH2Cl2 have been observed. A detailed spectroscopic study of these chromophores, including absorption, fluorescence emission, fluorescence lifetime, multiphoton excited fluorescence and 3PA coefficient were measured. The multibranched symmetrical oxadiazole derivatives display large three-photon absorption and strong upconversion fluorescence properties. Reference | Related Articles | Metrics Cited: Baidu(2)

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Preparation and Properties of Highly Monodisperse Spherical Poly(vinylsilsesquioxane) Nanoparticles CHEN Lian-Xi, LI Jie, LI Xi, ZHAI Peng-Cheng, ZHANG Jiang-Tao, ZHANG Zhong-Ming Chem. J. Chinese Universities    2013, 34 (6): 1460-1465.   DOI: 10.7503/cjcu20121002 Abstract （8176）      PDF（pc） （2201KB）（1474）       Knowledge map    Save In aqueous solution, highly monodisperse spherical poly(vinylsilsesquioxane)(PVSQ) particles with various sizes have been prepared successfully in the presence of surfactant sodium dodecyl benzene sulfo-nate(SDBS) using vinyl triethoxysilane(VTES) as precursor and ammonia hydroxide as catalyst by sol-gel method. The research results show that the amounts of catalyst(NH3·H2O) and surfactant(SDBS) have great effects on size and size distribution of PVSQ. However, the amount of precursor(VTES) has unobvious effect on size and size distribution of PVSQ. The shape, size and size distribution, structure, surface property and thermal behavior of the resulting products were analyzed and characterized by field emission scanning electron microscope(FESEM), Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS) and thermal gravimetric analysis(TGA), respectively. Related Articles | Metrics Cited: Baidu(4)