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A novel method for simultaneously determining the degree of deacetylation (DD), the degree of substitution (DS) and the distribution fraction of -COONa (δ -COONa) or -COOH (δ -COOH) in carboxymethyl chitosan (CM-chitosan) was developed by potentiometric titration. The effect of precipitate on the third inflection point, a common problem in the previous method, was eliminated by integrated application of alkaline titration and acidic titration. Calculating formulas of DS, DD and δ -COONa considering both the residues (GlcN and GlcNAc) and the carboxymethyl forms (-COONa and -COOH) were proposed. CM-chitosan products in different forms were examined to prove the reliability of the method. The standard deviation of DS, DD and δ -COONa of Na salt CM-chitosan (n = 9) were 0.109, 3.51% and 4.30%, respectively. As CM-chitosan was confirmed by IR and 1H NMR to be N,O-CM-chitosan, the method is suitable for the parameter determination of N-, O- and N,O-CM-chitosan. © 2011 Elsevier Ltd All rights reserved. Source

Liu Z.,Shandong University | Liu Z.,Qingdao Agricultural University | Wang Y.,Shandong University

This paper addresses the disturbance decoupling problem (DDP) of mix-valued logical networks by using both the semi-tensor product of matrices and the matrix expression of logical functions, and presents a number of new results on the DDP. First, in order to solve the DDP, a new algorithm is proposed to construct a kind of Y-friendly subspace for the state space of mix-valued logical networks. Second, based on the constructed Y-friendly subspace, several necessary and sufficient conditions are obtained for the existence of decoupling controllers, and a new control design procedure is established to deal with the DDP. Finally, an illustrative example is studied by the new method proposed in this paper, and two kinds of decoupling controllers are designed. The study of the illustrative example shows that the new method is effective in dealing with the DDP of mix-valued logical networks. © 2012 Elsevier Ltd. All rights reserved. Source

Tian J.,Qingdao Agricultural University
Journal of Food Composition and Analysis

Acetaldehyde is a natural by-product of the fermentation process, and its determination and quantitative analysis help to evaluate whether complete and proper fermentation has taken place. A new method was developed for sensitive determination and quantitative analysis of acetaldehyde in beer in our laboratory. Separation and determination of acetaldehyde were carried out by static headspace gas chromatography (HS-GC) with various experimental conditions. Calibration curves were obtained by plotting peak area versus concentration, and correlation coefficient of 6 standard level additions was ≥0.999. Measuring precision for acetaldehyde was ≤0.16% R.S.D. (relative standard deviation) under the condition of HS (25psi)/GC (16psi) when compared to HS (21psi)/GC (16psi). Configuration of two level temperatures made all the detecting values existing between upper control limit (UCL) and lower control LCL (limit) in comparison with one level configuration. In addition, the detecting threshold ranged from 0.5 to 12.1μgmL-1 using proposed parameters. Data displayed that accuracy and precision of detection were reliable for routine monitoring in beer. The method built in our laboratory could be used successfully to analyze the concentration of acetaldehyde in beer in the future. © 2010 Elsevier Inc. Source

Quan H.,Qingdao Agricultural University
Open Civil Engineering Journal

Although the specific surface area of type-2 fly ash, specified to be not less than 250 m2/kg in Japanese Industrial Standard, type-2 fly ash manufactured and available range from 300 m2/kg to 450 cm2/kg in Japan. In order to make clear of the effects of change in fineness of fly ash on the properties of air-entraining concrete, 2 series of laboratory experiments were carried out using 6 kinds fly ash with the specific surface area in the range from 250 m2/kg to 440 m2/kg. In the series 1 experiment, mix proportion was the same for 6 mixtures of fly ash, regardless of the change in fly ash properties. Water binder ratio, unit binder content, fly ash replacement ratio and unit water content were constant for all mixtures as well as the dosage of chemical admixture. In the series 2 experiment, 5 mixtures of concrete with the same materials, with the same unit binder content, with the same fly ash replacement ratio and with the same water binder ratio as those in the series 1 experiment were examined. However, unit water content and dosage of air-entraining agent were adjusted to obtain target slump and target air content. The test results indicated higher slump and lower air content and higher dosage of air-entraining agent for fly ash with higher specific surface area than those with lower specific surface area. Compressive strength was found to increase with the increases of specific surface area of fly ash, while drying shrinkage and carbonation were found to show different tendency with change in fineness of fly ash. © Hongzhu Quan. Source

Wang Z.-L.,Qingdao Agricultural University
Advanced Synthesis and Catalysis

This review examines recent advances in asymmetric catalytic decarboxylative addition reactions which have become a powerful method to form C-C and C-X bond using relatively cheap and stable carboxylic compounds. In these reactions, new C-C or C-X bonds are formed with extrusion of carbon dioxide (CO2). Asymmetric decarboxylative addition reactions have become alternatives to traditional addition reactions. Various asymmetric reactions between carboxylic acids and unsaturated compounds are summarized. The challenges and opportunities of these reactions are discussed. © 2013 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim. Source

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