利用两种不同来源的纤维素酶按照不同的滤纸酶活/CMC酶活[Filter Paper Activity/CMCase(F/C)]比值进行混合,酶解二次纤维后,借助电子显微镜、X-射线衍射以及红外光谱等手段,分析酶解对纤维超分子结构的影响。研究结果表明: F/C比值从0...利用两种不同来源的纤维素酶按照不同的滤纸酶活/CMC酶活[Filter Paper Activity/CMCase(F/C)]比值进行混合,酶解二次纤维后,借助电子显微镜、X-射线衍射以及红外光谱等手段,分析酶解对纤维超分子结构的影响。研究结果表明: F/C比值从0增加到2.5,纤维结晶度从65.49%增加到73.40%;F/C增加至3.0,结晶度下降至65.52%。纸张强度随着F/C值增加从21.78 Nm/g下降至16.57 Nm/g。酶解导致纤维细胞致密的次生壁结构疏松多孔,酶解由纤维表面向内层转移,单根纤维强度和成纸强度下降。展开更多
To solve the global optimization problems which have several local minimizers,a new F-C function is proposes by combining a lled function and a cross function.The properties of the F-C function are discussed and the c...To solve the global optimization problems which have several local minimizers,a new F-C function is proposes by combining a lled function and a cross function.The properties of the F-C function are discussed and the corresponding algorithm is given in this paper.F-C function has the same local minimizers with the objective function.Therefore,the F-C function method only needs to minimize the objective function once in the rst iteration.Numerical experiments are performed and the results show that the proposed method is very effective.展开更多
During the Folin Ciocalteu (F-C) micro-assay for the determination of phenolics in the presence of methanol, fine solids can form. In a previous paper, we hypothesized that the interference from alcohol on the F-C rea...During the Folin Ciocalteu (F-C) micro-assay for the determination of phenolics in the presence of methanol, fine solids can form. In a previous paper, we hypothesized that the interference from alcohol on the F-C reaction can be minimized depending on the particular procedure used to reach the alkalinity condition. In order to demonstrate our hypothesis we studied, by spectrophotometrically monitoring, the time-behaviour of the reactions carried out in the presence of different methanol concentrations at the same alkalinity condition from two protocols. The results showed that the interfering effect of methanol on the F-C micro-method can be affect and even prevented depending on working conditions. In particular, the formation of fine solids can be delayed, slowed down and prevented depending on the initial carbonate concentration used. We have explained why the initial carbonate concentration, used to reach the final alkalinity condition, plays an important role in the F-C reaction carried out in the presence of methanol. Moreover, the results from real-time monitoring showed that, differently from traditional F-C procedure, our procedure allows us to carry out the F-C micro method in the presence of 6% methanol, as an extreme concentration, reading the absorbance at real time 24 min. The real-time monitoring of absorbance can be considered as a useful means to explore the effect of other parameters on precipitate formation caused by the presence of methanol in the F-C reaction.展开更多
Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N,N-dimethyl-2-thiophenecarbo...Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N,N-dimethyl-2-thiophenecarboxamide, was synthesized from thiophene and dimethylcarbamyl chloride. The influences of the dosages of dimethylcarbamyl chloride and ZnCl2 catalyst, reaction temperature and time on the removal rate were further explored based on the reaction kinetics.The structure of the target product was characterized by means of MS,NMR and 13C NMR.The removal rate of thiophene was 98.14% after the reaction for 2 h and thiophene was almost removed after the reaction for 3 h under the optimal reaction conditions [a molar ratio of n(thiophene):n(dimethylcarbamyl chioride):w(ZnCl2)=1:12:10,300 r/min, 318 K and 101.325 kPa].The acylation of thiophene with dimethylcarbamyl chloride was approximately in accord with the first order kinetic equation at 303-323K.The activation energy was 53.9850 kJ/mol and the pre-exponential factor was 1.4521×10^9 h^-1.展开更多
Let R ＊θ G be the skew group ring with a F.C group G and the group homomrphism 8 from G to Aut（R）, the group of automorphisms of the ring R. In this paper,the necessary and sufficient condition such that R ＊θ G ...Let R ＊θ G be the skew group ring with a F.C group G and the group homomrphism 8 from G to Aut（R）, the group of automorphisms of the ring R. In this paper,the necessary and sufficient condition such that R ＊θ G will be Noetherian is given, which generalizes the results of LG. connel.展开更多
基金Supported by National Natural Science Foundation of China(No.11471102)Basic research projects for key scientific research projects in Henan Province(No.20ZX001)。
文摘To solve the global optimization problems which have several local minimizers,a new F-C function is proposes by combining a lled function and a cross function.The properties of the F-C function are discussed and the corresponding algorithm is given in this paper.F-C function has the same local minimizers with the objective function.Therefore,the F-C function method only needs to minimize the objective function once in the rst iteration.Numerical experiments are performed and the results show that the proposed method is very effective.
文摘During the Folin Ciocalteu (F-C) micro-assay for the determination of phenolics in the presence of methanol, fine solids can form. In a previous paper, we hypothesized that the interference from alcohol on the F-C reaction can be minimized depending on the particular procedure used to reach the alkalinity condition. In order to demonstrate our hypothesis we studied, by spectrophotometrically monitoring, the time-behaviour of the reactions carried out in the presence of different methanol concentrations at the same alkalinity condition from two protocols. The results showed that the interfering effect of methanol on the F-C micro-method can be affect and even prevented depending on working conditions. In particular, the formation of fine solids can be delayed, slowed down and prevented depending on the initial carbonate concentration used. We have explained why the initial carbonate concentration, used to reach the final alkalinity condition, plays an important role in the F-C reaction carried out in the presence of methanol. Moreover, the results from real-time monitoring showed that, differently from traditional F-C procedure, our procedure allows us to carry out the F-C micro method in the presence of 6% methanol, as an extreme concentration, reading the absorbance at real time 24 min. The real-time monitoring of absorbance can be considered as a useful means to explore the effect of other parameters on precipitate formation caused by the presence of methanol in the F-C reaction.
文摘Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N,N-dimethyl-2-thiophenecarboxamide, was synthesized from thiophene and dimethylcarbamyl chloride. The influences of the dosages of dimethylcarbamyl chloride and ZnCl2 catalyst, reaction temperature and time on the removal rate were further explored based on the reaction kinetics.The structure of the target product was characterized by means of MS,NMR and 13C NMR.The removal rate of thiophene was 98.14% after the reaction for 2 h and thiophene was almost removed after the reaction for 3 h under the optimal reaction conditions [a molar ratio of n(thiophene):n(dimethylcarbamyl chioride):w(ZnCl2)=1:12:10,300 r/min, 318 K and 101.325 kPa].The acylation of thiophene with dimethylcarbamyl chloride was approximately in accord with the first order kinetic equation at 303-323K.The activation energy was 53.9850 kJ/mol and the pre-exponential factor was 1.4521×10^9 h^-1.
基金Supported by the NSF of Educational Department of Henan Province(20025100003)
文摘Let R ＊θ G be the skew group ring with a F.C group G and the group homomrphism 8 from G to Aut（R）, the group of automorphisms of the ring R. In this paper,the necessary and sufficient condition such that R ＊θ G will be Noetherian is given, which generalizes the results of LG. connel.
