One of the bottlenecks for bioproduction of butyric acid as bulk chemical is the difficulty in separating butyric acid from the fermentation broth,compared with the petroleum-based chemical synthesis method.In the pre...One of the bottlenecks for bioproduction of butyric acid as bulk chemical is the difficulty in separating butyric acid from the fermentation broth,compared with the petroleum-based chemical synthesis method.In the present work,a novel separation methodology was developed based on an aqueous two-phase system with inor-ganic salts.Calcium chloride was screened out for effective separation of butyric acid from butyric acid-water-salt systems.Within appropriate concentration range of butyric acid and salt,butyric acid was enriched in the upper phase and most of calcium ions remained in the lower phase.This"salting out"effect is very efficient to separate butyric acid from the simulated butyrate fermentation broth,which consists of butyric acid and acetic acid with concentration ratio of 4︰1,so that the final ratio of butyric acid/acetic acid in the upper phase is improved to 9.87. The aqueous two-phase system was used to separate butyric acid from the actual fermentation broth with satisfac-tory result.展开更多
Advantages of the detached phenomena have influenced researchers to modify the conventional methods to promote it on the earth. Since 1994, the vertical directional solidification (VDS) technique has been employed f...Advantages of the detached phenomena have influenced researchers to modify the conventional methods to promote it on the earth. Since 1994, the vertical directional solidification (VDS) technique has been employed for the growth of bulk crystals, without the seed, without contact to the ampoule wall, without coating and without external pressure. An automated furnace was designed and fabricated for the controlled temperature gradients, growth conditions and parameters. The typical ingots growths of GaSb have shown the gap of 20 μm-145 μm and mobility μn = 1125 cm^2/V.sec at 300 K. Mobility is highest and five times larger than the attached growths. Dislocation density is the order of 104/cm2 in the conical region, decreases in the direction of growth, and in many crystals reached less than 103/cm2. The spontaneous gap formation due to the meniscus depends on the pressure differences and thermal state. GaSb grown ingots have shown progress in the properties of crystal grown ever, and attributed to reduce thermal stress without contact to the ampoule wall.展开更多
Since 1994, the vertical directional solidification (VDS) technique is employed for the growths of bulk crystals-without the seed, without contact to the ampoule wall, without coating and without external pressure, ...Since 1994, the vertical directional solidification (VDS) technique is employed for the growths of bulk crystals-without the seed, without contact to the ampoule wall, without coating and without external pressure, which leads to the detached growth. Growth velocities ranged from 3 mm/h to 10 mm/h, and rotation rates 10-20 rpm have been used. Ingots, 10-20 mm diameter and 60-65 mm length, have been grown with the conical ampoule geometry and these ingots have shown symmetric detachment. Crystals grown under such conditions showed the relatively low dislocation density and the highest carrier mobility,/tn = 5.9 x 104 cm2"Vl-sl than the crystal grown ever. For the detached crystals, the dislocation density is 104 cm"2 in conical region, and reached less than 103 cm-2 in the direction of the growth, when the ingots are not in contact with the ampoule wall. Experiments for indium-antimonide (InSb) growth have shown that the 80% growth environments have detachment, 15% entrapped in conical region and 5% attached.展开更多
Under the conditions of constant temperature and pressure,different influences of samples with different chemical components on the mechanism of nonlinear chemical reaction will cause different changes of the potentia...Under the conditions of constant temperature and pressure,different influences of samples with different chemical components on the mechanism of nonlinear chemical reaction will cause different changes of the potential-time relationship curve of the nonlinear chemical reaction system.Using it as the character,and using the B-Z nonlinear chemical system to use acetone and substrates in samples as main dissipative substances qua an example,the principle of nonlinear chemical fingerprint has been researched and discussed in detail.At the same time,the general method for calculating the system similarity about nonlinear chemical fingerprint was also put forward,and similarities of nonlinear chemistry fingerprints of different batches of Guhan Yangshengjing and 18 sorts of other samples were calculated by Euclidean distance,correlation coefficient,included angle cosine and system similarity,at the same time,the various similarities were analyzed.The results showed that,both of correlation coefficient and included angle cosine are unable to be used as the criterion for quantitatively evaluating the similarity of nonlinear chemistry fingerprint;as non-parametric similarity,Euclidean distance can accurately reflect the feature differences in the fingerprints,but as parametric similarity,sometimes,Euclidean distance can not accurately reflect the relative extent of characteristic difference in the nonlinear chemical fingerprints;system similarity can most truthfully reflect the characteristic difference in the nonlinear chemical fingerprints,and is the best evaluating method among the four ones.Therefore,system similarity can be used to quantitatively calculate the similar extent between the nonlinear chemical fingerprints.An economical,simple and convenient,easy pushing and effective method for identifying and evaluating complicated samples has successfully been put forward.展开更多
A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction (DLLME) combining with high performance liquid chromatography (HPLC) was developed for the analysis of four toxic anilines i...A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction (DLLME) combining with high performance liquid chromatography (HPLC) was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design (OAD) with OA25(54) matrix. Analysis of variance (ANOVA) and percent contribution (PC) were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity (r2 〉 0.99) over the studied range (50-1000 ng g-l) for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections (LODs) and limit of quantitations (LOQs) ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.展开更多
The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away ...The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away from the equilibrium and open systems without the complementarity of the dissipation substances have important significance for the throng characterization and whole content analysis of chemical components in samples.Various factors influencing on nonlinear chemical fingerprint,such as reactant species and their concentrations,electrode types,temperature,stir rate,the sort,dosage and granularity of the sample,etc.were amply researched by a nonlinear chemistry reaction,namely,damp B-Z oscillation which used acetone and glucose as the main dissipative substances.In addition,the quantitative information on the whole of chemical components in samples and the traits and applications of the fingerprint were investigated.The method and its important conditions for determining nonlinear chemistry fingerprint used in distinguishing and evaluating complex samples were successfully put forward.展开更多
基金Supported by the National High Technology Research and Development Program of China(2009AA02Z206,2006AA02Z239)the National Basic Research Program of China(2007CB707805)the Ministry of Science and Technology,China
文摘One of the bottlenecks for bioproduction of butyric acid as bulk chemical is the difficulty in separating butyric acid from the fermentation broth,compared with the petroleum-based chemical synthesis method.In the present work,a novel separation methodology was developed based on an aqueous two-phase system with inor-ganic salts.Calcium chloride was screened out for effective separation of butyric acid from butyric acid-water-salt systems.Within appropriate concentration range of butyric acid and salt,butyric acid was enriched in the upper phase and most of calcium ions remained in the lower phase.This"salting out"effect is very efficient to separate butyric acid from the simulated butyrate fermentation broth,which consists of butyric acid and acetic acid with concentration ratio of 4︰1,so that the final ratio of butyric acid/acetic acid in the upper phase is improved to 9.87. The aqueous two-phase system was used to separate butyric acid from the actual fermentation broth with satisfac-tory result.
文摘Advantages of the detached phenomena have influenced researchers to modify the conventional methods to promote it on the earth. Since 1994, the vertical directional solidification (VDS) technique has been employed for the growth of bulk crystals, without the seed, without contact to the ampoule wall, without coating and without external pressure. An automated furnace was designed and fabricated for the controlled temperature gradients, growth conditions and parameters. The typical ingots growths of GaSb have shown the gap of 20 μm-145 μm and mobility μn = 1125 cm^2/V.sec at 300 K. Mobility is highest and five times larger than the attached growths. Dislocation density is the order of 104/cm2 in the conical region, decreases in the direction of growth, and in many crystals reached less than 103/cm2. The spontaneous gap formation due to the meniscus depends on the pressure differences and thermal state. GaSb grown ingots have shown progress in the properties of crystal grown ever, and attributed to reduce thermal stress without contact to the ampoule wall.
文摘Since 1994, the vertical directional solidification (VDS) technique is employed for the growths of bulk crystals-without the seed, without contact to the ampoule wall, without coating and without external pressure, which leads to the detached growth. Growth velocities ranged from 3 mm/h to 10 mm/h, and rotation rates 10-20 rpm have been used. Ingots, 10-20 mm diameter and 60-65 mm length, have been grown with the conical ampoule geometry and these ingots have shown symmetric detachment. Crystals grown under such conditions showed the relatively low dislocation density and the highest carrier mobility,/tn = 5.9 x 104 cm2"Vl-sl than the crystal grown ever. For the detached crystals, the dislocation density is 104 cm"2 in conical region, and reached less than 103 cm-2 in the direction of the growth, when the ingots are not in contact with the ampoule wall. Experiments for indium-antimonide (InSb) growth have shown that the 80% growth environments have detachment, 15% entrapped in conical region and 5% attached.
基金supported by the National Key Technologies R & D Program (2009GJD20033)the International Scientific and Technological Cooperation Project from Chinese Ministry of Science and Technology (2007DFA40680)
文摘Under the conditions of constant temperature and pressure,different influences of samples with different chemical components on the mechanism of nonlinear chemical reaction will cause different changes of the potential-time relationship curve of the nonlinear chemical reaction system.Using it as the character,and using the B-Z nonlinear chemical system to use acetone and substrates in samples as main dissipative substances qua an example,the principle of nonlinear chemical fingerprint has been researched and discussed in detail.At the same time,the general method for calculating the system similarity about nonlinear chemical fingerprint was also put forward,and similarities of nonlinear chemistry fingerprints of different batches of Guhan Yangshengjing and 18 sorts of other samples were calculated by Euclidean distance,correlation coefficient,included angle cosine and system similarity,at the same time,the various similarities were analyzed.The results showed that,both of correlation coefficient and included angle cosine are unable to be used as the criterion for quantitatively evaluating the similarity of nonlinear chemistry fingerprint;as non-parametric similarity,Euclidean distance can accurately reflect the feature differences in the fingerprints,but as parametric similarity,sometimes,Euclidean distance can not accurately reflect the relative extent of characteristic difference in the nonlinear chemical fingerprints;system similarity can most truthfully reflect the characteristic difference in the nonlinear chemical fingerprints,and is the best evaluating method among the four ones.Therefore,system similarity can be used to quantitatively calculate the similar extent between the nonlinear chemical fingerprints.An economical,simple and convenient,easy pushing and effective method for identifying and evaluating complicated samples has successfully been put forward.
基金supported by the National Natural Science Foundation of China (20905073 & 20975105)
文摘A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction (DLLME) combining with high performance liquid chromatography (HPLC) was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design (OAD) with OA25(54) matrix. Analysis of variance (ANOVA) and percent contribution (PC) were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity (r2 〉 0.99) over the studied range (50-1000 ng g-l) for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections (LODs) and limit of quantitations (LOQs) ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.
基金supported by the National Key Technologies R & DProgram (2009GJD20033)the International Scientific and Technological Cooperation Project (2007DFA40680) from the Ministry of Scienceand Technology of China
文摘The thermodynamic systems and dynamic model suitable for determining the nonlinear chemical fingerprints of samples were analyzed.The results indicated that the damp nonlinear chemical reactions in close systems away from the equilibrium and open systems without the complementarity of the dissipation substances have important significance for the throng characterization and whole content analysis of chemical components in samples.Various factors influencing on nonlinear chemical fingerprint,such as reactant species and their concentrations,electrode types,temperature,stir rate,the sort,dosage and granularity of the sample,etc.were amply researched by a nonlinear chemistry reaction,namely,damp B-Z oscillation which used acetone and glucose as the main dissipative substances.In addition,the quantitative information on the whole of chemical components in samples and the traits and applications of the fingerprint were investigated.The method and its important conditions for determining nonlinear chemistry fingerprint used in distinguishing and evaluating complex samples were successfully put forward.