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10 November 2007, Volume 28 Issue 11

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高等学校化学学报2007年第28卷第11期目次

2007, 28(11):  0.  doi:

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下期目次预览

2007, 28(11):  0.  doi:

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研究论文

Study of Two Sandwich-type Manganese Polyoxometalates as Potential MRI Contrast Agents

LI Zhong-Feng^1,2, LI Wei-Sheng^1,2, LIAO Pei-Qiu^1,2, WEI Lai^1,2, LI Xiao-Jing¹*, JING Feng-Ying¹, PEI Feng-Kui¹*, WANG Xu-Xia^2,3, LEI Hao³

2007, 28(11):  2021-2025.  doi:

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Two sandwich-type manganese polyoxometalates, K₁₀[Mn₄(PW₉O₃₄)₂]·22H₂O and Na₁₆[Mn₄(H₂O)₂(P₂W₁₅O₅₆)₂]·53H₂O, were synthesized and characterized by IR and elemental analysis. T₁-relaxivities of the two compounds were higher than or similar to that of the commercial MRI contrast agent(Gd-DTPA), and relaxivities in BSA and hTf were also reported. T₁-weighted MR imaging of rat kidney and liver showed a good enhancement post i.v. injection of the two manganese polyoxometalates. The results indicate the two sandwich-type manganese polyoxometalates being potential contrast agents for MRI.

Structure and Electrical Properties of Pr and Sm Doped CeO₂ and Ce₆MoO₁₅ Based Solid Electrolytes

ZHOU De-Feng¹*, YE Jun-Feng¹, LI Dong-Feng¹, JIANG Xin-Hua¹, MENG Jian²

2007, 28(11):  2026-2029.  doi:

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Sm and Pr doped CeO₂ and Ce₆MoO₁₅ based materials were synthesized by sol-gel method. The structure of the powders were characterized by X-ray diffraction(XRD), Raman spectra, field emission scanning electron microscopy(FE-SEM) and the electrical conductivity of the samples was investigated by AC impedance spectroscopy. By comparing the structure and electrical properties of different systems, it could be concluded that the electrical property of Ce₆MoO₁₅ based system is better than that of CeO₂ system. The added Mo element resulted in the increase of gain size and improved the grain boundary conductivity notably below 600 ℃, while the Pr dopant induced the smaller grain size and improved the grain boundary conductivity of the materials.

ZSM-5/SAPO-5 Composite Molecular Sieves Synthesized by Vapor-phase Transport Technique

ZHANG Qiang, LI Chun-Yi*, SHAN Hong-Hong, YANG Chao-He

2007, 28(11):  2030-2034.  doi:

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The main drawback of the synthesized ZSM-5(core)/AlPO₄-5(shell) binary structure zeolites is large numbers of self-existent AlPO₄-5 zeolites and low acidity of the aluminophosphate molecular sieve. In order to overcome these problems, a series of ZSM-5(core)/SAPO-5(shell) binary structure zeolites were synthesized by vapor-phase transport technique(VPT). Phosphoric acid, pseudoboehmite, and silica sol were used as phosphorus, aluminum and silicon sources, respectively. Triethylamine(TEA) was used as the template. These synthesized samples were characterized by means of X-ray diffraction, scanning electron microscope, X-ray energy dispersive spectroscopy, Fourier transformed infrared spectroscopy and N₂-adsorption, respectively. The results indicate that the synthesized samples belong to binary structure zeolies with a ZSM-5 core and a SAPO-5 shell. The condition for preparing dry-gel and composition of liquid phase affect the crystallization of zeolites. Crystallinity of the synthesized samples increases as the crystallization temperature increased and the crystallization time is protracted. Using VPT technique for the synthesis of binary structure zeolites could reduce the SAPO-5 and composite molecular sieves size, and improve the distribution of SAPO-5 on the ZSM-5 surface. The experiments of heavy oil cracking show that the core/shell binary structure zeolite samples were more favourable for formation of light olefins than the mechanical mixture.

Preparation, Characterization and Gas Responsibilities of Al Doped α-Fe₂O₃

SI Shu-Feng*, YANG Song-Lin, YAN Xi

2007, 28(11):  2035-2039.  doi:

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Pure and Al doped α-Fe₂O₃ materials were prepared by a solution phase controlled hydrolysis me-thod, and were characterized by XRD, SEM and ICP techniques. Gas-sensing properties were carried out on gas sensors from these materials under laboratory and humid conditions. The experiments indicate that the crystalline size of Al doped α-Fe₂O₃ materials is less than that of pure one, and their conductivity increases obviously; the resultant Al doped Fe₂O₃ gas sensor exhibites a high response and a short response/recovery time in the detection of low concentrations of various combustible gases. The Al doped Fe₂O₃ sintered at 400 ℃, which is more stable than one sintered at 300 ℃, is suitable as a gas sensor for ethanol alcohol.

Determination of Nine Plasticizers in the Body of Hericium Caput-Medusae by Liquid Chromatography-Tandem Mass Spectrometry

XIE Ping^1,2, SONG Hui³, LIU Ying-Jie³, JIN Qin-Han¹*

2007, 28(11):  2040-2045.  doi:

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A composition from the cultured body of [Hericium caput-medusae(Bull.: Fr.) Pers.] was analyzed quantitatively and qualitatively by gas chromatography-mass spectrometry(GC-MS) and liquid chromatography-tandem mass spectrometry(LC-MS/MS). Di-n-octyl o-phthalate(DOP) and di-n-butyl o-phthalate(DBP)were identified by manually mass spectrum analyzing and mass spectrum bank matching. Since plastics are not inert, the plasticizers might migrate into the cultured mushroom and cause contamination. A simple LC-MS/MS method was established for the determination of nine plasticizers in cultured edible mushroom due to potential contamination. The method shows a good recovery(71.6%—82.2%) for various levels of spiked samples(0.01—0.10 mg/L).The relative standard deviations were in the range of 2.11%—8.53% for all plasticizers studied. The limits of detection were in the range of 0.002—0.30 μg/L.

Determination of Azithromycin in Human Plasma by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry

HU Wan-Qun, XU Yu*, LIU Fei, RUI Lei, GUO Qing-Xiang*

2007, 28(11):  2046-2050.  doi:

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A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated for determination of azithromycin in human plasma with erythromycin as the internal stan-dard. Chromatographic separation was performed on a Lichrospher CN column(4.6 mm×150 mm) with a mixture of acetonitrile and water(containing 0.1% formic acid and 0.1% ammonium acetate, volume ratio 40∶60) as mobile phase. Selected ion monitoring was specific for azithromycin and erythromycin(IS). The assay was linear over the mass concentration range 2.34—600 ng/mL and the correlation coefficients for the calibration curves ranged from 0.997 to 0.999. The intra- and inter-day precisions, calculated from quality control samples, were less than 10%. Protein precipitation with methanol was chosen for sample preparation method. The recoveries ranged from 94.13% to 97.04 % and matrix effect ranged from 92.50% to 107.87%. The method was applied to bioequivalence study after oral administration of 500 mg azithromycin to 24 healthy volunteers.

Biotransformation of Deoxyaconitine of Metabolite of Aconitine by Human Intestinal Bacteria and Electrospray Ionization Tandem Mass Spectrometry

ZHAO Yu-Feng^1,2, SONG Feng-Rui¹, YUE Hao¹, GUO Xin-Hua¹, LI Hui-Lin¹, LIU Zhi-Qiang¹, LIU Shu-Ying¹*

2007, 28(11):  2051-2055.  doi:

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To study the biotransformation of deoxyaconitine in intestine, aconitine was incubated with human intestinal bacteria in vitro. The metabolites of deoxyaconitine were investigated by ion trap and Fourier transform ion cyclotron resonance electrospray ionization tandem mass spectrometry directly. Aconitine and its metabolites formed the protonated molecular ion [M+H]⁺ in the positive ion mode. According to the m/z of [M+H]⁺, the molecular weight of the metabolite was determined and the structure was characterized by using MSn and the data in literature. The results show that deoxyaconitine could be transformed by human intestinal bacteria. Deoxyaconitine was converted into more than ten kinds of new metabolites such as mono-ester aconitum alkaloids, diester aconitines and lipo-alkaloids by deacetylation, debenzoylation, dehydroxylation, demethylation and esterification. Diester deoxyaconitine is very toxic. When deoxyaconitine was transformed into mono-ester aconitum alkaloids and lipo-alkaloids by human intestinal bacteria, the toxicity decreased.

Analyses of Spinosad and Its Degradates from Light Irradiation

YANG Cheng-Dui*, SONG Li-Hui

2007, 28(11):  2056-2059.  doi:

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In this paper we report 5-stage mass spectrum fragmentations of spinosad A and D. Degrading rate of spinosad under ultraviolet light irradiation was also investigated with selection reaction monitoring(SRM) mode. Degradates of spinosad were analyzed with liquid chromatography coupling with mass spectrometry, and the chemical structures of main degradates were also assigned. It can be concluded that (1) forosamine on 17-carbon can be easily lost, but difficult for rhamnose sugar; (2) spinosad concentration decreased when irradiation time increased, degrading rate was up to about 70% for irradiating 484 min, and 11 degradates were produced. These degradates were products of the oxidation, reduction, and hydrolytic reactions.

Studies on Chemical Constituents of Leaves of Actinidia kolomikta

JIN Yong-Ri¹, GUI Ming-Yu¹, LI Xu-Wen¹, LU Juan¹, Masaki Baba², Toru Okuyama², XU Ji-Qing¹*

2007, 28(11):  2060-2064.  doi:

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Seven compounds were isolated from Actinidia kolomikta(Rupr.et Maxim.)Planch.. The structures of the compounds were deduced by spectroscopic methods(1D NMR, 2D NMR, MS) as kaempferide-3-O-rutinoside(Ⅰ), kaempferide-7-O-(4"-O-acetylrhamnosyl)-3-O-glucoside(Ⅱ), kaempferide-7-O-(4"-O-acetylrhamnosyl)-3-O-rutinoside(Ⅲ), kaempferol-3-O-glucoside(Ⅳ), kaempferol-3-O-rutinoside(Ⅴ), kaempferide-3-O-glucoside(Ⅵ) and kaempferide-7-O-rhamnosyl-3-O-rutinoside(Ⅶ). Compounds Ⅰ—Ⅲ are new compounds, compounds Ⅰ—Ⅳ were obtained from this plant for the first time.

Determination of Different Protein Expression in Neural Retina of Diabetic Rats by Mass Spectrometry

WANG Ya-Dong¹, WU Jin-Dao², JIANG Zhong-Li¹, WANG Xue-Hao¹, LIU Chao¹*, TONG Ming-Qing¹*

2007, 28(11):  2065-2072.  doi:

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High-resolution two-dimensional polyacrylamide gel electrophoresis(2DE) was used to separate total proteins extracted from neural retinas of diabetic and age-matched control rats and followed by computer assisted image analysis to quantitatively compare the differences in protein expression between diabetic and age-matched control rats. Totally 3122±37(n=3) spots were detected in normal samples and 2702±21(n=3) spots were detected in the samples of diabetic rats. The expression levels of ca. 150 protein spots was different between the control group and diabetic retinas(P<0.05). Compared with the control group, the expression level of 68 protein spots was up-regulated(P<0.05) and 82 protein spots was down-regulated(P<0.05) in diabetic rats, and 20 different expressed proteins were identified by peptide mass fingerprinting(PMF) or peptide sequence. Seven of the identified proteins were proved to be relevant in predicting pathology of diabetic retinopathy(DR) by previous study and ten proteins are newly discovered proteins associated with DR. The results provide a basis for further research on the diabetic retinopathy.

Construction Techniques and Characteristics in Nanometer Insulin Core-Ferritin Revealed by MALDI-TOF Mass Spectrometry and Electronic Spectrometry

HUANG He-Qing^1,2,3*, CHEN Ping¹, ZHU Bin-Lin¹, LIN Qing¹, LUO Lian-Zhong¹

2007, 28(11):  2073-2077.  doi:

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Liver ferritin of Sphyma zygaena(SZLF) with small-scale preparation was done by electrophoresis approach. SZLF consists of iron core, protein shell, and tunnel across its shell. The pathways for dissociation and recombinant both iron core and protein subunits in SZLF were investigated with transmission electron microscopy. Through dissociation(pH=1.5) of hydrochloric acid and dialysis of separation membrane for preparing ferritin subunits, these free subunits were constructed into apoSZLF under the condition of acid-basis neutralization. In this recombinant process, INS was encapsulated with apoSZLF for constructing a nanometer insulin core(NIC) within the protein shell. The experimental evidence for constructing a NIC-SZLF was revealed by electronic spectrometry, MALDI-TOF MS, and SDS-PAGE, respectively, indicating this novel pathway for a NIC-ferritin encapsulated with the protein subunits and insulin. This technology described can be used to supply an important science evidence for constructing a drug carrier with controlling and releasing characteristics in nanometer peptide core-ferritin.

研究简报

Investigation of the Interaction Between Nystatin and Solid-supported Phospholipid Membranes

WANG Qing^1,2,3,4, YANG Xiao-Hai^1,2,3,4, WANG Hong^1,2,4, WANG Ke-Min^1,2,3,4*

2007, 28(11):  2078-2080.  doi:

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Nystatin is a polyene antifurgal drug to which many molds and yeasts are sersitive, including cryptococcus neoformans, candida, aspergillus, etc. To realize the mechanism of nystatin more particularly, the techniques of SPR and impedance were used to investigate the interaction between nystatin and two kinds of solid-supported phospholipid membranes. The results show that nystatin could interact with pure phospholipid membranes, whether they are monolayer or bilayer. In addition, impedance spectra show that ion channels may be formed when nystatin interacted with phospholipid membranes.

研究论文

Hydrolysis and Intra-molecular Condensation of o-Aminodiphenyl Ether Diazonium Salts

LU Jun-Rui^1,2*, MA Xia-Miao¹, LIU Mei², YIN Ning², CHEN Li-Ran¹, BAO Xiu-Rong¹

2007, 28(11):  2081-2085.  doi:

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The preparation of o-hydroxyldiphenyl via diazotization and hydrolysis of o-aminodiphenyl ether involves the competition between hydrolysis and intra-molecular condensation, and there is no report about it so far. A series of effect factors related to the reactions were discussed, especially, the effects of substituents, metals and their ions. The rules of intra-molecular condensation of diazonium salt of o-aminodiphenyl ether under the catalysis of metallic ions were suggested, and the mechanism also was predicted. Metals and their ions may have an obvious catalytic effect on the intra-molecule condensation of o-aminodiphenyl ether diazonium salt, and few effect on hydrolysis. The intra-molecule condensation would be accelerated if there was any metal or its ion in the reaction system, and it led largely to the increase of the product of dibenzofurans.

Convenient Stereoselective Approach to Herbarumin Ⅲ

兰州大学化学化工学院, 功能有机分子化学国家重点实验室, 兰州 730000

2007, 28(11):  2086-2091.  doi:

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Herbarumin Ⅲ, a naturally occurred phytotoxin which has a ten-membered lactone ring, was isolated from Phoma herbarum. The root growth inhibiting activity of Herbarumin Ⅲ is ten times than 2,4-dichlorophenoxyacetic acid. The stereoselective total synthesis of Herbarumin Ⅲ (3), along with its 8-epimer 22, was succeeded in 13 steps starting from n-butyraldehyde and 1,5-pentandiol on the bassis of Brown's asymmetric allylation, with modified Julia olefination and Yamaguchi's macro-lactonization as the key steps.

Passive Optical Limiting Performance of Solid-State Polymer-Indium Phthalocyanine Composite Materials

LIU Ying¹, CHEN Yu¹*, FENG Miao^1,3, LIN Ying¹, Doyle J. J², Blau W. J.², CAI Liang-Zhen¹*

2007, 28(11):  2092-2095.  doi:

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Optical limiting, an important application of nonlinear optics, useful for the protection of human eyes and optical sensors from intense laser pulse, is of great inertest to the private industry, law enforcement and military. In this paper, indium phthalocyanine-based polymer solid-state passive optical limiters were fabricated by embedding the phthalocyanine as inclusion in poly(methylmethylacrylate) host. These composite films exhibit an enhanced nonlinear optical response and lower saturable fluence for optical limiting in comparison to the same Pc molecules in solution. All open aperture Z-scans performed at 532 nm display a decrease in transmittance about the focus which is typical for an induced positive nonlinear absorption of incident light due to reverse saturable excited state absorption.

研究简报

Isolation and Identification of a New Triterpene from Neonauclea sessilifolia

KANG Wen-Yi^1,2*, ZHANG Bai-Rang¹, HAO Xiao-Jiang²

2007, 28(11):  2096-2098.  doi:

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Neonauclea sessilifolia belongs to Rubiaceae and its chemical constituents and pharmacological investigations were seldom reported. To search the active constituents of the plant, the ethanol of the dried stem of Neonauclea sessilifolia was separated via reflux with ethanol, then the crude product was extracted with ethyl acetate and n-butanol in sequence. The ethyl acetate extract was further isolated by silica gel and Sephadex LH-20 column chromatography. A new triterpene was obtained, and the structure was identified as 3β, 7β, 21β, 23-tetrahydroxyolean-12-ene-28-oic acid via 1D, 2D NMR techniques and HR-EI-MS analysis.

Synthesis and Characterization of a New Small Organic Molecules Blue-Light Emitting Host Materials Suitable for Solution Process

WANG Zhi-Qiang^1,2, LIU Hong-Mei^1,2, ZHENG Cai-Jun^1,2, WAN Jing^1,2, PENG Zhao-Kuai³, ZHANG Xiao-Hong¹*

2007, 28(11):  2099-2101.  doi:

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The current trend for fabricating OLEDs is solution processing in the scope for low-cost manufacturing, but most small organic molecules must be deposited in vacuum to fabricate devices due to their poor solubility. In this paper, a new soluble anthracene derivative 2-tert-butyl-9,10-bis(9,9-dipropylfluorenyl)anthracene(TBPFA) was designed and synthesized. The compound exhibited pure-blue-light emitting(λ_max=443 nm in dilute dichloromethane, λ_max=450 nm in solid film) and high fluorescence quantum efficiency. The none-doped and doped single-layer devices were prepared successfully by spin coating process with TBPFA as blue-light emitting material and blue-light emitting host material respectively. In the doped device, TBPFA can transport energies to TBPe which is a good blue-light emitting material efficiently.

研究论文

Growth Behavior of Amorphous Fe—N Thin Films Applicability of Conventional Dynamic Scaling Approach

XU Wei¹, WANG Xin²*, JIA Hui³, ZHENG Wei-Tao², LONG Bei-Hong²

2007, 28(11):  2102-2105.  doi:

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Dynamic scaling approach is an effective tool for studying the growth behavior of roughness surfaces. The growth behavior of amorphous Fe—N thin films grown by dc magnetron sputtering at 250 ℃ substrate temperature was investigated. The surface morphology of the films appeared as a set of continuous mounds and exhibited scale-invariant self-affine fractal. The measured dynamic scaling components(α=0.82±0.21, β=0.44±0.07, and 1/z=0.54±0.07) are consistent with the conventional dynamic scaling relationship z=α/β. The intermediate value of growth exponent β agrees well with the thermal reemission model suggested by Karabacak et al. It might be concluded that both reemission of atoms and surface diffusion are the surface smoothing effects for the shadowing growth of amorphous Fe—N films at high substrate temperatures.

Effect of Hydrophobic Chain Length of Surfactants on Foam Stability at High Temperature

CAO Xu-Long², HE Xiu-Juan¹, ZHAO Guo-Qing¹ , SONG Xin-Wang², WANG Qi-Wei², CAO Yan-Bin³, LI Ying¹*

2007, 28(11):  2106-2111.  doi:

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The foam stability stabilized by α-olefin sulfonate(AOS) with different hydrophobic chain lengths at temperature below 100 ℃ and above 200 ℃ was investigated by foam column decay method and foam block in sand-pack pipe, respectively. The results show that the foam stability increases with the increase of hydrophobic chain length. Dynamic surface tension, interfacial rheometer and molecular simulation were used to study the foam stablity mechanism at a high temperature. From the experiment results, we can see that when the hydrophobic chain length was longer than 20 carbon atoms, the hydration of surfacrtant head could not support the hydrophobic chain to keep vertical or unattached, and the hydrophobic chains cross-link with each other, which increase the strength of the foam film, decrease the diffusion of the gas through the film and make the foam stable at a high temperature.

Preparation of Highly-specific Surface Area MnO_x-CeO₂ Catalysts by a Template Precipitation Method and Its Performance for Low Temperature CO Oxidation

MA Jing-Meng, LU Ji-Qing, WANG Yue-Juan, BAO Ming-Min, LUO Meng-Fei*

2007, 28(11):  2112-2117.  doi:

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Nanosized MnO_x-CeO₂ catalysts with a high-surface area were prepared by a template precipitation method, with Ce(NO₃)₃ and Mn(NO₃)₂ as the precursors and surfactant CTAB as the templating agent. Their catalytic activities for CO oxidation were examined. The catalysts were characterized by XRD, Raman spectroscopy, H₂-TPR and N₂ adsorption techniques. BET specific surface areas of the catalysts were between 160 and 170 m²/g when the Mn mass fraction was lower than 34.3%. However, surface area decreased with further increasing Mn mass fraction. XRD results show that there was only CeO₂ phase when the Mn mass fraction was lower than 34.3%, while Raman spectra indicate the existance of α-Mn₂O₃. The high specific surface area was benefical to CO oxidation activity. TOF of the catalysts decreased with increasing Mn content, indicating that the highly dispersed Mn species with a small crystallite size were the active species. H₂-TPR results suggest that the activitiy was related to the high-valance Mn species. High calcination temperature caused growth of the catalyst crystallite size and decrease of surface areas, as well as decline of avarage valance of Mn species, which led to decline in the catalytic activity.

Foaming Properties and Dynamic Surface Tension of Sodium Alkylbenzenesulfonates with Different Structures

WANG Xiao-Chun¹, ZHANG Lei¹, GONG Qing-Tao¹, WANG Lin¹, ZHANG Lu¹, LI Zhen-Quan², ZHAO Sui¹*, YU Jia-Yong¹

2007, 28(11):  2118-2123.  doi:

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Foaming properties and dynamic surface tension(DST) of aqueous solutions of a series of sodium 2,4,5-trialkyl benzene sulfonates and sodium 2,5-dialkyl benzene sulfonates were determined. The parameters of DST (t*, n, R_1/2) were correlated with the foaming ability of the same surfactant solution. The results indicate that the molecular diffusion in the solution, adsorption and arrangement on the air/water interface were changed with the changes of molecular structures: with the increase of the alkyl chain length, the values of t* and n increase, and the value of R_1/2 decreases. For 2,4,5-trialkyl benzene sulfonates, 2-alkyl and 5-alkyl have strong steric hindrance, which have a strong influence on the molecular arrangement on the air/water interface, with increasing the chain length, foam stability decreases. While the 4-alkyl chain has a weak influence on the structure of adsorption film, the 4-alkyl chain almost doesn't influence the foam stability. For 2,5-dialkyl benzene sulfonates, the branched-alkyl chain is more flexible, which is characterized by more densely packed adsorbed molecules and higher film elasticity of the adsorption film. Therefore, the foam stability is higher than that of sodium 2,4,5-trialkyl benzene sulfonates. In the case of modified Bikerman method, DST is the key factor controlling the foaming ability.

Electrochemical Performance of Spherical Ni(OH)₂ Coated with Y(OH)₃

FAN Jing, YANG Yi-Fu*, YU Peng, CHEN Wei-Hua, SHAO Hui-Xia

2007, 28(11):  2124-2127.  doi:

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The effects of surface coating of Y(OH)₃ on the electrochemical performance of spherical Ni(OH)₂ were studied by cyclic voltammetry(CV) with soft-embedded electrode(SE-E). The results show that a two-step oxidation process exists in the oxidation procedure of Ni(OH)₂ corresponding to the formation of Ni(Ⅲ) and Ni(Ⅳ), respectively, in which Ni(Ⅳ) species is not stable and can dissociate into NiOOH and oxygen. Therefore, the conversion of Ni(Ⅲ) to Ni(Ⅳ) is regarded as a side reaction. The presence of Y(OH)₃ on the particle surface could restrain the side reactions, especially the formation of Ni(Ⅳ). The charge acceptance of the battery with Ni(OH)₂ coated with 1.61%(mass fraction) Y as the positive active material can reach 92.7% at 60 ℃. The specific capacity of Ni(OH)₂ coated with 0.55%(mass fraction) Y can reach 241.3 mA·h/g at 60 ℃.

Synthesis, Conformation Analysis and Asymmetric Catalytic Oxidation Performance of Mono-faced Bridged Chiral Porphyrins

REN Qi-Zhi*, DING Xiao-Jian, YUAN Xian-Xia, WANG Ai-Qin

2007, 28(11):  2128-2132.  doi:

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Novel mono-faced bridged chiral porphyrins 1a and iron complex 1b were synthesized and characterized. Conformation analysis was performed by using molecular mechanics conformation search method. The theoretic viable lowest energy conformation of compound 1a greatly coincided with ¹H NMR data. Compound 1b was used as the catalyst in asymmetric styrene devivatives epoxidation. In the absence of nitrogen base ligand, the epoxides were formed on a lower e.e.(25%—28%), when axial ligand was present, compound 1b exhibited an increased epoxidation rate, yield and much higher e.e.(73%—80%). The added nitrogen base can efficiently block the oxidation reaction at the unhinded side of the porphyrin ring and directionally control the oxygen transfer and substrate approach to the chiral cavity.

Comparison of Catalytic Performance of Mn₃O₄-loaded Two-dimensional and Tree-dimensional Msoporous Carbon Mterials in Znc-air Bttery

LI Feng, LIU Hai-Jing, WANG Yong-Gang, LI Hui-Qiao, XIA Yong-Yao*

2007, 28(11):  2133-2137.  doi:

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Mn₃O₄ nano-particles were loaded on the surface of different carbon materials by the wet-penetration method, and the electrocatalytic performance of these composite materials were evaluated as cathode in zinc-air battery. It was found that the mesoporous carbon (CMK-3) with three-dimensional ordered structure exhibits the better catalytic performance than that of two-dimensional ordered mesoporous carbon (OMC) by charging/discharging and cyclic voltammograms test. The images of TEM indicate that Mn₃O₄ nano-particles were all loaded on the outer-surface of the carbon materials. In particular, the unique structure of the Mn₃O₄/CMK-3 composite can provide both effective gas diffusion path and sufficient effective three-phase interface area, thus resulting in its high electrocatalytic activity for oxygen reduction.

Performance of Activated Carbon/Cobalt Oxide Xerogels Electrochemical Capacitors

CHENG Jie*, CAO Gao-Ping, YANG Yu-Sheng

2007, 28(11):  2138-2141.  doi:

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Electrochemical capacitors composed with high capacitive activated carbon and cobalt oxide xerogels electrodes were studied in 7 mol/L KOH aqueous solution. The electrochemical capacitance performance of the electrochemical capacitors was studied by means of cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tests. The maximum charge/discharge voltage of the electrochemical capacitors was in the range of 1.4—1.6 V, and a maximum energy density of 15.4 W·h/kg and a maximum power density of 23.5 kW/kg were obtained on the basis of total weight of the two electrodes except current collector. High performance obtained indicates that the activated carbon/cobalt oxide xerogels electrochemical capacitor is an attractive system being worthy to make great efforts to investigate deeply further.

Properties of Electrochemistry, EPR and Time-resolution Photovoltage of a Series of Hydroxyphenyl Porphyrins Compounds

ZHENG Wen-Qi^1,2, SHAN Ning¹, LI Yan-Cai¹, FA Huan-Bao¹, WANG Xing-Qiao¹*

2007, 28(11):  2142-2145.  doi:

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The effects of the number and the location of hydroxyl substituents on electrochemistry, EPR and transient photovoltage properties of a series of hydroxyphenyl porphyrins were studied for the first time. The study results indicate that all oxidation-reduction reactions occur on the macroring of porphyrin. With the increase of the number of the periphery substituents of porphyrin, the conjugate system is getting to be easy for oxidation, difficult for reduction. An increase in structure symmetry would cause positive shift of half-wave potential values. Thereinto the electron-donation effect of the porphyrin compounds on their electrochemistry property played a main role. At the normal state, porphyrin molecules do not have EPR signal. However, light excitation may cause a transition of porphyrin molecules from singlet to triplet. At the same time, the change from diamagnetism to paramagnetism occurred to porphyrin molecules. In this case, the two un-paired electrons are nearby each other and cause a strong interaction, giving EPR signal with sharp peak at g=2.000. The g value increased with an increase in electron cloud density. Time-resolution photovoltage is generated from the free photoacoustic carrier. The decay of photovoltage is closely related to the molecular structure and the separation velocity of their charge, which decreased on the whole with an increase in the number of periphery hydroxyl substituents.

Application of Ba_1-xPr_xCoO₃ Cathode Materials in IT-SOFC

WANG Jin-Xia¹ *, YAO Ying¹, XU Da-Peng², SU Wen-Hui²

2007, 28(11):  2146-2149.  doi:

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Cathode materials Ba_1-xPr_xCoO₃(x=0.3, 0.4, 0.5, 0.6) were prepared with wet chemical method. TG-DTA and sintering curves show that the materials were crystallized in a single perovskite phase at around 950 ℃. The SEM images show that the prohibition of the particle growth and the decrease of the hole ratio were produced when the increase of Pr ions dopant to a certain quantity. The results of the single cell tests show that the fuel cell with the cathodes x=0.5 have the best output performance and the greatest short current density and the maximum output power density, so it has more proper ratio than the other samples and fit Y³⁺-doped BaCeO₃ based solid electrolyte material perfectly.

QSAR and Binding Mode of a Series of Combretastatin Analogues as Tubulin Inhibitors

TIAN Ran^1,2, JI Yu-Bin¹, LIU Zhen-Ming², JIN Hong-Wei², ZHANG Liang-Ren²*, LIN Wen-Han^1,2*

2007, 28(11):  2150-2155.  doi:

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The quantitative structure-activity relationship(QSAR) of a series of combretastatin analogues with ring B modification was studied. The two dimensional structure-activity relationship was carried out by genetic function analysis(GFA) method. The results indicate that Apol, PMI-mag, Dipole-mag, Hbond donor, and RadOfGyration descriptors contributed significantly to the activities. Furthermore, a three dimensional structure-activity was performed via comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA). An analyses of CoMFA and CoMSIA models resulted in a cross validated coeffieciency(q²) of 0.630 and 0.634 respectively, which showed a strong predictive ability. The contourmaps of CoMFA and CoMSIA provided smooth and interpretable explanation of the structure-activity relationship of the selected compounds. A molecular docking was used to analyze and validate the QSAR models. Those results provide a useful information to design novel tubulin inhibitors.

Molecular Dynamics Simulation on the Complex of the Tobramycin and 16S rRNA A Site

FENG Yu¹, ZHANG Xu-Dong¹, CHENG Wei-Xian¹,CAO Huai¹, LIU Ci-Quan^1,2*

2007, 28(11):  2156-2161.  doi:

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A 3.6 ns molecular dynamics simulation was carried out on the complex system of tobramycin and 16S rRNA in order to understand the speciality recognition mechanism between tobramycin and 16S rRNA at the molecular level. The results demonstrate that two looped out bases(A1492 and A1493) of the A site is the flexible part, while ringⅠand ringⅡ of tobramycin are the most conservative elements. Moreover, ringⅠand ringⅡ of tobramycin may be function conservative unit which may participate in the specificity recognition for tobramycin binding to the 16S rRNA A site. In addition, a structural water molecule was detected during the whole MD simulation trajectory, which bridged the contacts between ringⅡ(N3)and ringⅠ(N6') of tobramycin and enhanced the rigid of tobramycin structure. There is one hydration site with the higher water density in the vicinity of ringⅠand ringⅡ of tobramycin. This result is consistent with the crystal structure detected that the most water-medial hydrogen bonds were listed in the same situation. Our study illustrates that recognition mechanism between tobramycin and 16S rRNA A site was due to a few hydrogen bond and water molecule interactions, which play a great role in designing high affinity and speciality inhibitors of 16S rRNA A site based on tobramycin.

In-Situ Electrochemistry Conductivity Measurement and Kinetics Analysis of Polyaniline Film

YANG Gui-Fu^1,2, SONG Ji-Xia^1,2, YUAN Fu-Yu^1,2, WANG Wei¹, XU Xiao-Yu¹, NIU Li¹*

2007, 28(11):  2162-2166.  doi:

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Conductivity of electrodeposited polyaniline was measured in-situ during the potential running, which is achieved at a homemade in-situ electrochemistry conductometer(ECC) integrated with a two-band electrode. The electrochemical response and change in resistance were recorded spontaneously. Furthermore, the first order reaction kinetics at various potentials was examined on basis of the changes of resistance, and the aging process of PANI film in the acid solution was also explored.

Studies on the Electronic Structure and Bonding of EuB₆ and Calculation of Its Optical Constants

JIANG Jun, BIAN Jiang, LI Le-Min*

2007, 28(11):  2167-2170.  doi:

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The electronic structure of EuB₆ was studied by means of density functional method. The information of energy band structure and density of states were obtained with a higher accuracy. The bonding in EuB₆ solid was studied, and the characteristics of its energy band structure and semi-metallic property were clarified based on the analysis of the orbital interaction among atoms. The dielectric function, reflectivity, optical conductivity and energy-loss function spectra were calculated. The results are in good agreement with the experiments, showing the reliability of the electronic structure information obtained by energy band calculations.

Prediction of Dihydrofolate Reductase Inhibitors Activity Using Machine Learning Methods

CHEN Xiao-Mei¹, RAO Han-Bing¹, HUANG Wen-Li², LI Ze-Rong¹*

2007, 28(11):  2171-2178.  doi:

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Machine learning methods, including Support Vector Machine, Artificial Neural Network, Regularized Logistic Regression and K-Nearest Neighbor, are used to develop the classification models for a set of 761 DHFR inhibitors. Constitutional descriptors and topological descriptors are calculated to characterize the structural and physicochemical properties of compounds and Kennard-Stone method is used to design the training set and Metropolis Monte Carlo simulated method is used for feature selection. It is shown that SVM method outperforms other machine learning methods used in this study and the final SVM model after feature selection can give a prediction accuracy of 91.62%. This suggests that SVM method with proper training set design and feature selection is potentially useful for the prediction of the activity of a diversity set of DHFR inhibitors.

Theoretical Study of Hydroxylation of Nitrosodimethylamine, Nitrosopyrolidine, and Nitrosopiperidine by Dioxirane

LI Lan^1,2, TENG Guo-Feng¹, LI Zong-He¹*

2007, 28(11):  2179-2182.  doi:

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The hydroxylation reaction mechanisms of nitrosodimethylamine, nitrosopyrolidine and nitrosopiperidine by dioxirane were theoretically investigated at the B3LYP/6-31G** level. It is found that there are two paths(separately, syn- and anti-) to the hydroxylation reaction of the three nitrosoamines that have the same hydroxylation reaction mechanisms. The study of the potential surface shows that the hydroxylation of the three nitrosoamines by dioxirane has a relatively low energy barrier. The result of the theoretical study shows that the α-hydroxylation products of these nitrosoamines form easily by dioxirane.

Accurate Prediction of Excited Energy of Rydberg States of OClO and Ab Initio Investigation of Excited States of OClO Anion with a Low Energy

WEI Zi-Zhang¹, LI Bu-Tong¹, PAN Qing-Jiang², ZHANG Hong-Xing¹*

2007, 28(11):  2183-2186.  doi:

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By using the complete active space self-consistent field (CASSCF) method with large atomic natural orbital (ANO-L) basis set, seven electronic states of the OClO- anion were calculated. The optimized geometry of the ground state with ANO basis set agrees better with the experimental and previous theoretical values. Furthermore, the stable geometries of three singlet and three triplet excited states were obtained. Taking the further correlation effects into account, the second-order perturbation (CASPT2) calculations were carried out for the energetic calibration. Furthermore, the Rydberg states of the OClO radical were investigated by using multiconfigurational CASPT2 (MS-CASPT2) theory under the basis set of ANO-L functions augmented with an adapted 1s1p1d Rydberg functions that have specially been built for this study. Ten electronic excited states were found for the transition from 3b₁ electron into the Rydberg orbitals. The 3b₁→ns and 3b₁→np series agreed excellent with the experimental values, and the assignment of 3b₁→3d series supported the results of Marston. Meanwhile, two and four Rydberg states were computed for the transition of 1a₂ and 5b₂ electron, respectively.

研究快报

Electron Transportation in the TiO₂/ZnO Film Electrodes and Application for Dye-sensitized Solar Cells

PANG Shan^{1, 2}, XIE Teng-Feng¹, ZHANG Yu¹, WEI Xiao¹, DU Zu-Liang², WANG De-Jun¹*

2007, 28(11):  2187-2189.  doi:

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The TiO₂ based dye-sensitized solar cells doped with different sizes of ZnO nanorods were fabricated and studied by photoelectrochemical measurements. The results show that the energy conversion efficiency of the dye-sensitized solar cells after the addition of ZnO nanorods(1%, mass fraction) was increased by 6%—20% in comparison with that without ZnO nanorods. The effect of different sizes of ZnO nanorods on the electronic transportation properties was studied in the composite semiconductor film by means of transient photovoltage technology(TPV). The result indicates that the electron diffusing velocity in N3-sensitized TiO₂/ZnO film electrode was about 1—3 order of magnitude faster than that in TiO₂ electrode. The experimental results indicate that the TiO₂/ZnO electrode can improve the electron transport, decrease the recombination, enhance V_oc, and increase efficiency of energy conversion.

研究论文

Preparation of Poly(p-dioxanone) with High Molecular Weight from Dihydroxyl Terminated Prepolymers Using HDI as Chain Extender

YANG Ke-Ke, ZENG Qiang, WANG Xiu-Li, ZHU Xiao-Lan, ZHOU Yan, WANG Yu-Zhong*

2007, 28(11):  2190-2194.  doi:

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Poly(p-dioxanone)(PPDO) is one of most promising biodegradable materials, however its application was restricted because the rigorous synthetic condition and longer reaction time were needed in order to obtain products with a high molecular weight by common ring-opening polymerization. In this work, a new approach was developed by chain extending of dihydroxyl-terminated PPDO prepolymer(HPPDO) using hexamethylenediisocyanate(HDI) as the chain extender in order to obtain high molecular weight PPDO in a short time. HPPDO was prepared by ring-opening polymerization of p-dioxanone(PDO) catalyzed by SnOct₂ and initiated by 1,4-butanediol(BD). The results obtained show that HPPDO prepolymers can react with Hexamethylenediisocyanate effectively, and the molecular weights of the resulting chain-extended products increase several decade times in less than one hour compared with the prepolymers. The highest viscosity-average molecular weight of the resulting polymer can reach 257000 g/mol. Both the prepolymer and the chain extended product were characterized by ¹H NMR.

Preparation of Molecularly Imprinted Polymer Microspheres and Their Recognition for Chenodeoxycholic Acid

CHEN Fen-Qiang, LIU Shou-Xin*, FANG Yu, WANG Yi-Juan, ZHANG Zhao-Yang, JIANG Yu

2007, 28(11):  2195-2199.  doi:

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Molecularly imprinted polymer microspheres were obtained by deposition polymerization with methyacrylic acid(MAA) as the functional monomer, trimethylolpropane trimethacrylate(TRIM) and ethylene glycoldimethacrylate(EDGMA) as the cross-linkers, chenodeoxycholic acid(CDCA) as the template molecule, and 2,2-azobis-isobutyronitrile as the initiation agent. The average size of the molecularly imprinted polymer microspheres was between 200 nm and 300 nm. The binding properties of the template molecule on MIPMS were evaluated by Scatchard analysis. The selective adsorptions of target molecule on MIPMS were studied. The results indicate that there were two class binding sites in polymers and the MIPMS showed a specific affinity toward chenodeoxycholic acid.

Multi-network Reinforced Structure of PET/PC Alloys by Low Temperature Solid-state Reactive Blend

GUO Wei-Hong*, WANG Xiao-Guang, XU Dong-Dong, ZHANG Wan-Li, YIN Guo-Rong, WU Chi-Fei

2007, 28(11):  2200-2204.  doi:

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By adding of chain extender and thermo plastic elastomer, PET/PC reactive alloys were prepared via low temperature solid-state blending. Novel toughening alloy is gained with outstanding mechanical properties and thermal properties. The structures of PET/PC alloys were studied and the multiple network which was formed by this processing greatly reinforced the alloy.

Preparation and Properties of Hydrophilic DEA/Organosilane Hybrid Antifogging Coating

SHA Peng-Yu, LIU Yan, XIE Lei, CUI Zhan-Chen*

2007, 28(11):  2205-2209.  doi:

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The TEOS-derived silica was modified with epoxy by copolymerization of TEOS with GPTMS. The epoxy sites have become anchors for cross-linking the nanoparticles of the skeletal backbone of the silica hybrids by attachment of DEA. The synthesis material was determined by FTIR, TGA and AFM . The hybrids have an excellent film-forming capability and possess a high thermstability. After addition of DEA, the inorganic-organic hybrid system containing abundant —OH group has a wettable surface and long antifogging time. The contact angles of the hybrid film for water were less than 31° and the coating meet the requirements for transparence. The existing silica gel network improved the scratch property. So the coating have an exce-llent mechanical property.

Preparation of Polyaniline Nanorods by Allelochemicals Gallic or Ferulic Acid/PAM Fibers

ZHOU Tian^1,2, CHEN Jian-Li³, CHEN Di³, ZHANG Wei³, GUO Ji-Xun¹*, GONG Jian³

2007, 28(11):  2210-2213.  doi:

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In order to study the slow releasing carrier material of allelochemicals, polyaniline(PANI) doped with gallic acid or ferulic acid was prepared via gallic or ferulic acid/PAM fibers. The structure and morphology of the PANI were characterized by IR spectra, XRD patterns, and SEM images. The results indicate that the products were PANI doped with gallic acid or ferulic acid. And the morphology of the PANI nanorods with diameters of 200—300 nm was obtained. In addition, the changes of the PANI conductivity with content variation of acid in the fibers and the molar ratio of APS to An were investigated.

Preparation of High Molecular Weight PVA by Emulsifier-free Emulsion Polymerization

QI Yu-Dong, YE Guang-Dou, LI Shou-Qun, XU Jian-Jun*

2007, 28(11):  2214-2218.  doi:

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The high molecular weight PVAc was prepared via an emulsifier-free emulsion polymerization, by using redox initiator system. The PVAc was then hydrolyzed to high molecular weight PVA. The influence of polymerization condition on molecular weight and distribution of PVAc is studied, such as the polymerization temperature, initiator concentration and conversion of monomer. The control method of structure of linear high molecular weight PVA is discussed. The results show that the PVA with DP=9899 can be gotten via the emulsifiter-free emulsion polymerization at room temperature(14—20 ℃). The polymerization process has notable influence on the molecular weight and structure of PVA. The high molecular weight PVA with narrow distribution and orderly structure is obtained in constant velocity period of polymerization, while the branching and cross linkage of PVA become prominence during acceleration period, causing a bad effect on linear degree of PVA. Therefore, the control of molecular weight and chain structure of PVA can be achieved by manipulating polymerization process.

Flame Retardant and Thermal Degradation Kinetics of Novel Copolyester Containing Phosphorus Linked Pendant Groups

HUANG Nian-Hua*, ZHANG Qiang, LI Zhi-Hua, XIONG Qi

2007, 28(11):  2219-2224.  doi:

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Thermal stability and thermal degradation kinetics of poly(ethylene terephthalate)(PET) and flame retardant copolyester(FR-PET) containing phosphorus linked pendant groups were investigated by a conventional dynamic thermogravimetric analysis(TG) under highly purity N₂ atmosphere at different heating rates between 10 and 40 K/min and the flame retardant of PET and FR-PET were studied by limiting oxygen index(LOI) method. The thermal degradation activation energy of PET and FR-PET were determined by using Flynn-Wall-Ozawa method. The thermal degradation kinetic mechanism and models of PET and FR-PET were determined by the selection of different mechanical models, by which the isothermal kinetic equations and thermal degradation velocity curves of the main degradation process were obtained. The flame retardant of PET by incorporation of phosphorus unit linked pendant groups was improved. The degradation of FR-PET was determined by the breaking of P—C and P—O bonds, and thermal stability of FR-PET was lower than that of PET. Thermal degradation activation energies of PET and FR-PET were in the range of 194—227 kJ/mol and 184—209 kJ/mol(0.1≤α≤0.85), respectively. The solid-state decomposition mechanism of PET and FR-PET corresponded to the controlled decelerating α-t curve, a reaction order mechanism and the mechanism functions f(α) were 3(1-α)^2/3(0.1≤α≤0.85).The thermal degradation velocity of the main degradation process of PET and FR-PET were near. Flame retardant mechanism of novel copolyester phosphorus containing linked pendant groups was most likely through the gas phase rather than the condensed phase.

Mechano-Chemical Effects in the Process of Soybean Protein Ultra High-Pressure Microfluidization

TU Zong-Cai*, WANG Jing-Qin, LI Jin-Lin, LIU Cheng-Mei, RUAN Rong-Sheng, LI Xue-Ting

2007, 28(11):  2225-2228.  doi:

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The mechano-chemical effects refer to the physical, chemical and structure changes of substancees caused by mechanical effect .The protein's mechano-chemical effects in the process of ultra high-pressure microfluidization, and the effects of mechano-chemical to thermal stability of soybean protein were studied in this paper. The results show that the particle size of soy bean protein decreased and the distribution sharpened, and disulfide linkage and drainage groups were brokendown, thermal stability increased after ultra high-pressure microfluidization. With the pressure of homogenization increasing, the effects became more obvious.