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Dong Z.R.,Xiamen University | Li Y.Y.,Xiamen University | Yu S.L.,Xiamen University | Sun G.S.,Guangxi Research Institute of Chemical Industry | Gao J.X.,Xiamen University
Chinese Chemical Letters | Year: 2012

The new polydentate mixed-N, P, O chiral ligands have been synthesized by the condensation of bis(o-formylphenyl)-phenylphosphane and R-phenylglycinol in CHCl 3, and fully characterized by IR, NMR and EIMS spectra. These ligands were employed with a simple Ni complex Ni(PPh s) 2Cl 2 in situ as catalytic systems for asymmetric transfer hydrogenation of ketones, and the corresponding optical alcohols were obtained with up to 84% ee under mild conditions. © 2012 Zhen Rong Dong.


Zhang Y.,Guangxi University | Zhang Y.,Xiamen University | Zhang Y.,Guangxi Research Institute of Chemical Industry | Li Q.,Guangxi University | And 9 more authors.
Bioresource Technology | Year: 2015

A new technology for the pretreatment of natural cellulose was developed, which combined mechanical activation (MA) and metal salt treatments in a stirring ball mill. Different valent metal nitrates were used to investigate the changes in degree of polymerization (DP) and crystallinity index (CrI) of cellulose after MA+metal salt (MAMS) pretreatment, and Al(NO3)3 showed better pretreatment effect than NaNO3 and Zn(NO3)2. The destruction of morphological structure of cellulose was mainly resulted from intense ball milling, and the comparative studies on the changes of DP and crystal structure of MA and MA+Al(NO3)3 pretreated cellulose samples showed a synergistic interaction of MA and Al(NO3)3 treatments with more effective changes of structural characteristics of MA+Al(NO3)3 pretreated cellulose and substantial increase of reducing sugar yield in enzymatic hydrolysis of cellulose. In addition, the results indicated that the presence of Al(NO3)3 had significant enhancement for the enzymatic hydrolysis of cellulose. © 2014 Elsevier Ltd.


Liang L.,Guangxi University | Zhao W.,Guangxi Research Institute of Chemical Industry | Meng F.,Guangxi University | Liu L.,Guangxi University | Lin C.,Guangxi University
Spectroscopy Letters | Year: 2013

In this work, three new amide compounds of ferulic acid (FA) were synthesized. The fluorescence and ultraviolet spectroscopy were explored to study the interactions between three amide compounds of FA and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results showed that the fluorescence quenching mechanism between BSA and three amide compounds of FA were mainly static quenching and nonradiation energy transfer at 25°C, 30°C, and 37°C. The Stern-Volmer quenching constants, the binding constants, and the number of binding sites and corresponding thermodynamic parameters ΔH, ΔG, and ΔS were calculated at different temperatures. From the thermodynamic parameters, we concluded that the action force was mainly a hydrophobic interaction. According to the Forster theory of nonradiation energy transfer, the binding distances (r) between BSA and amide compounds are less than 7 nm. Furthermore, the effects of amide compounds on the conformation of BSA were analyzed using synchronous fluorescence spectroscopy. © 2013 Copyright Taylor and Francis Group, LLC.


Liang X.,Guangxi University | Liang X.,Qinzhou University | Huang Z.,Guangxi University | Zhang Y.,Guangxi University | And 3 more authors.
Polymer Bulletin | Year: 2013

The aim of this study was to develop a sugarcane bagasse (SCB)-based biodegradable superabsorbent hydrogels (SAH) with a good swelling. To this end, SCB was firstly mechanically activated by home-made high efficiency stirring mill to enhance its reactivity by breaking the lignin seal and decreasing crystallinity of cellulose in SCB. Then, the SAH were synthesized by graft copolymerization of acrylic acid (AA) onto SCB with different mechanical activation times (tM) by using ammonium persulfate/sodium sulfite redox pair as an initiator in the presence of a crosslinker (N,N0-methylenebisacrylamide, MBAAm). The effect of tM on the equilibrium swelling capacity (Qeq), swelling kinetics of the SAH in deionized water, as well as the influences of pH, electrolytic media, and temperature on Qeq were studied. In addition, the products were characterized by scanning electron microscopy and differential scanning calorimetry. The results showed that mechanical activation promoted the graft copolymerization and thereby altered the Qeq of the SAH. The swelling process of the SAH exhibited anomalous swelling behavior and first-order dynamics, and the Qeq of the SAH was pH, salt, and temperature dependent. © Springer-Verlag Berlin Heidelberg 2013.


Li X.-H.,Guangxi University | Zhang Y.-J.,Guangxi Research Institute of Chemical Industry | Pan L.-P.,Guangxi University | Wei Y.-S.,Hechi College
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

Neutral leach residue of zinc calcine (NLRZC) was mechanically activated by a stirring ball mill. Subsequently, the changes in physicochemical properties and dissolution kinetics in sulphuric acid were studied. The crystalline structure, morphology, particle size and specific surface area of the non-activated and mechanically activated NLRZC were characterized by X-ray diffraction, scanning electron microscope, particle size analyzer and volumetric adsorption analyzer, respectively. The characterization results indicate that mechanical activation (MA) induced remarkable changes in the physicochemical properties of NLRZC. The leaching experiments show that MA significantly enhances the leaching reactivity of NLRZC using the zinc extraction as evaluating index. After NLRZC is mechanically activated for 30 min and 60 min, the activation energy decreases from 56.6 kJ/mol of non-activated NLRZC to 36.1 kJ/mol and 29.9 kJ/mol, respectively. The reaction orders of the non-activated, 30 and 60 min activated NLRZC dissolution with respect to H2SO 4 concentration were found to be 0.34, 0.30, and 0.29, respectively. © 2013 The Nonferrous Metals Society of China.


Li H.,Beijing University of Technology | Wang J.,Beijing University of Technology | Huang K.,Beijing University of Technology | Huang K.,Guangxi Research Institute of Chemical Industry | And 3 more authors.
Materials Letters | Year: 2011

The multi-layer TiO2 nanotube array thin films have been formed by anodic oxidation method via adjusting the outer voltage during oxidation process in glycerol electrolyte containing 0.3% NH4HF2. The diameter of the nanotube array increases with the outer voltage, and the length of nanotube in every layer increases with the anodic oxidation time. These multi-layers bring new possibilities to tailor the properties of the TiO2 nanotube array thin films formed via anodic oxidation method. Further, such multi-layer structure provide a new approach to evaluate the growth rate of TiO2 nanotube, which will help us to understand more deeply the formation mechanism of the TiO2 nanotubes. The growth rate of TiO2 nanotube array is respectively 1.2 and 3.6 μm/h under the anodic voltage of 30 V and 60 V. These multi-layer TiO2 nanotube array thin films may exhibit lots of potential applications in photoelectrochemical fields. © 2011 Elsevier B.V. All rights reserved.


Zhang Y.,Guangxi University | Huang Z.,Guangxi University | Yang C.,Guangxi University | Huang A.,Guangxi University | And 4 more authors.
Starch/Staerke | Year: 2013

This study has focused on the preparation of partially pregelatinized cassava starch (PPCS) by mechanical activation (MA) using a customized stirring ball mill. The changes in degree of gelatinization, crystal structure, particle size, surface morphology, powder characteristics, and pasting properties of cassava starch mechanically activated for different time were investigated by various characterizations. The results showed that MA could significantly destroy the crystal structure of starch granules, contributing to the increase of cold-water solubility, flowability, and floodability, the variations of particle size and surface morphology, and the decrease in pasting temperature, viscosity of cooked PPCS paste, breakdown, and setback. It was also found that the PPCS with different degree of gelatinization could be prepared by controlling the milling time. With the unique properties induced by MA, the potential use of PPCS as excipient in pharmaceutical formulations is discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Huang Z.,Guangxi University | Wang N.,Guangxi University | Zhang Y.,Guangxi University | Zhang Y.,Guangxi Research Institute of Chemical Industry | And 2 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2012

This current work is concerned with the pretreatment of sugarcane bagasse (SCB) by mechanical activation (MA) using a self-designed stirring ball mill and surface modification of SCB using aluminate coupling agent (ACA). The untreated and differently treated SCBs were used to produce composites with poly(vinyl chloride) (PVC) as polymer matrix. The activation grade (Ag) measurement and Fourier transform infrared (FTIR) analysis of SCB showed that MA enhanced the condensation reaction between ACA and hydroxyl groups of the SCB fibres, which obviously increased the hydrophobicity of SCB. It was found that the mechanical properties of both the PVC composites reinforced by SCB with and without ACA modification increased with increasing milling time (tM). Scanning electron microscopy (SEM) analysis showed that MA pretreatment significantly improved the dispersion of SCB in the composites and interfacial adhesion between SCB and PVC matrix, resulting in better mechanical properties of the composites. © 2011 Elsevier Ltd. All rights reserved.


Lai K.,South China Agricultural University | Lai K.,Guangxi Research Institute of Chemical Industry | Chen S.,South China Agricultural University | Hu M.,South China Agricultural University | And 4 more authors.
Postharvest Biology and Technology | Year: 2012

A bacterial strain SG-6, isolated as an endophyte from the root tissue of Sophora tonkinensis, was identified as Paenibacillus polymyxa based on morphology, 16S rDNA gene analysis and Biolog tests. The strain was found to be highly effective in reducing postharvest green mold decay of citrus fruit caused by Penicillium digitatum. In an in vitro assay by dual-culture of strain SG-6 and P. digitatum on potato dextrose agar plates, the bacterium significantly inhibited growth of P. digitatum. Conidial germination of the pathogen was greatly inhibited in the presence of the living bacterial cell suspensions. In tests of in vivo activity, the unwashed cell suspension of strain SG-6 was more effective than the washed cell suspension and culture filtrate. Green mold control improved when the period between treatment with strain SG-6 and inoculation with the pathogen was increased. The concentration of the antagonist also had a significant effect on biocontrol effectiveness. At the concentration of 1×10 9cellsmL -1 of strain SG-6, the disease incidence and lesion diameter declined to 18.3% and 5.5mm, respectively, which were significantly lower than control after 5d of incubation at 25°C. Population of strain SG-6 increased rapidly in citrus fruit wounds when inoculated at 25°C but remained static at 6°C. The bacterium also significantly reduced the natural development of green mold decay of citrus fruit following storage at 25°C for 4 weeks or at 6°C for 4 weeks followed by 25°C for 2 weeks. Furthermore, it did not impair the quality parameters, including weight loss, firmness, total soluble solids, ascorbic acid, and titratable acidity. To our knowledge, this is the first report about antagonistic P. polymyxa strain SG-6 as a promising biocontrol agent against postharvest green mold of citrus fruit. © 2012 Elsevier B.V.


Huang Z.,Guangxi University | Tan Y.,Guangxi University | Zhang Y.,Guangxi Research Institute of Chemical Industry | Liu X.,Guangxi University | And 3 more authors.
Bioresource Technology | Year: 2012

This work reports that cellulose laurate could be directly produced by mechanical activation-strengthened solid phase synthesis (MASPS) in a customized stirring mill with using bagasse pulp and lauric acid as materials in an environmentally friendly way. Cellulose laurates with different degree of substitution were obtained under different synthesis conditions without the use of organic co-reagents and solvents. The characterization results showed that cellulose laurates had great changes in surface morphologies and crystal structures compared with bagasse pulp because of the intense milling and introduction of laurate groups, but still retained the cellulose I crystalline form of the native cellulose. MASPS could be considered as a simple, efficient and green method for the production of long chain cellulose esters. © 2012 Elsevier Ltd.

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