[ Objective] The aim of this study was to establish the optimum cpSSR-PCR system for Jatropha curcas Linn. [ Method] cpSSR-PCR amplification system for Jatropha curcas Linn influenced by five factors including Taq DNA...[ Objective] The aim of this study was to establish the optimum cpSSR-PCR system for Jatropha curcas Linn. [ Method] cpSSR-PCR amplification system for Jatropha curcas Linn influenced by five factors including Taq DNA polymerase, Mg^2＋ , DNA template, dNTP and primer were optimized from several levels. [ Result] The optimum concentration of 20 μl reaction system was 10 × Buffer, 2.00 mmol/L Mg^2＋ , 2 U/μl Taq DNA polymerase, 0.2 mmol/L dNTP, 0.2 μmol/L primer and 35 ng/μl DNA template. [ Conclusion] The optimum annealing temperature for cpSSR-PCR reaction system is 52 ℃, and the cpSSR reaction system is steady and reproducible.展开更多
[Objective] The aim was to establish the optimal rye-specific PCR reaction system for rye.[Method] The ordinary wheat ＂Chinese Spring＂,S165,rye,octoploid triticale and hexaploid triticale were used as materials to c...[Objective] The aim was to establish the optimal rye-specific PCR reaction system for rye.[Method] The ordinary wheat ＂Chinese Spring＂,S165,rye,octoploid triticale and hexaploid triticale were used as materials to carry out study on the effect of the amount of template DNA,primers,dNTPs,Mg2＋ concentrations,Taq DNA polymerase and annealing temperature on the rye-specific PCR reaction system of rye.[Result] The genomic DNA extracted by modified CTAB DNA extraction method showed high quality,which was satisfied for the PCR reaction template.The rye-specific PCR reaction system was 25 μl,including 10 × buffer solution,1.5 mmol/L MgCl2,200 μmol/L dNTP,40 ng primers,40-60 ng DNA template and 1 U Taq DNA polymerase.[Conclusion] The optimal rye-specific PCR reaction system was established,which provided basis for the identification of exogenous germplasm of rye in wheat background.展开更多
[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR ...[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.展开更多
[Objective] This research aimed to search a best method for extracting the genomic DNA of Cymbidium ensifolium and establish the optimized ISSR-PCR reaction system.[Method] Genomic DNA was extracted from C.ensifolium ...[Objective] This research aimed to search a best method for extracting the genomic DNA of Cymbidium ensifolium and establish the optimized ISSR-PCR reaction system.[Method] Genomic DNA was extracted from C.ensifolium leaves by modified CTAB method.ISSR-PCR reaction system for C.ensifolium was optimized.[Result] High-quality genomic DNA was obtained from C.ensifolium.The 25 μl optimized ISSR-PCR reaction system for C.ensifolium contained 2.5 μl 10× PCR buffer,2.5 mmol/L MgCl2,240 ng template DNA,160 μmol/L dNTPs,1.25 U Taq DNA polymerase,0.4 μmol/L primer and 15.78 μl ddH2O.The optimal PCR procedures were：94 ℃ pre-denaturation for 5 min and then 40 cycles,94 ℃ denaturation for 30 s,50-60 ℃ annealing for 30 s （annealing temperature according to different primers）,72 ℃ extension for 50 s and a 72 ℃ extension for 7 min.[Conclusion] An optimized ISSR-PCR reaction system for C.ensifolium was established,which provides a basis for further study on genetic diversity of C.ensifolium by using ISSR molecular marker technique.展开更多
[Objective] By using the genomic DNA of Cymbidium faberi Rolfe as template,the factors that affect the result of ISSR-PCR reaction system were researched and the optimal system was established.[Method] The genomic DNA...[Objective] By using the genomic DNA of Cymbidium faberi Rolfe as template,the factors that affect the result of ISSR-PCR reaction system were researched and the optimal system was established.[Method] The genomic DNA was extracted from C.faberi Rolfe with method of modified CTAB.Different factors which affected ISSR amplification reaction were optimized.[Result] High-quality genomic DNA was obtained from C.faberi Rolfe.And the optimal reaction system was as follows：25 μl amplification reactions system contained 2.5 μl 10 × PCR buffer,2.0 mmol/L MgCl2,60 ng template DNA,160 μmol/L dNTPs,1.25 U Taq DNA polymerase,0.4 μmol/L ISSR primer and 15.85 μl ddH2O.The optimal amplification procedures were pre-denaturing for 5 min at 94 ℃,followed by 40 cycles of denaturing for 30 s at 94 ℃,annealing for 30 s at a temperature of 2-3 ℃ lower than melting temperature of each primer pair,extension for 50 s at 72 ℃.Then extension step of 7 min at 72 ℃ was performed.[Conclusion] The optimal system could provide a favorable basis for further study on genetic diversity of C.faberi Rolfe by using ISSR molecular marker technique.展开更多
[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats （ISSR） fingerprinting. [Method] In order to seek ...[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats （ISSR） fingerprinting. [Method] In order to seek standardizing PCR reaction set-up, an orthogonal design was used to optimize ISSR-PCR amplification system of Bryaceae in five factors （Mg2＋, dNTPs, primer, DNA template, Taq DNA polymerase） at four levels respectively. [Result] A suitable ISSR reaction system was obtained, namely： 20 μl reaction system containing 5 ng of DNA template, 0.2 μmol/L primer, 2.25 mmol/L MgCl2, 0.6 U of Taq DNA polymerase, 0.4 mmol/L dNTPs. Proper annealing temperature was found at 48-50 ℃.The above system and six ISSR-PCR primers were used for the PCR amplification of 14 samples from Bryaceae and the related species in Mniaceae. A total of 86 bands were amplified, all showed polymorphism. NJ cluster analysis showed a star-shaped cladogram. [Conclusion] The results manifested that ISSR fingerprinting could provide the appropriate degree of polymorphism at low taxonomic level, so it would be a useful tool to provide additional evidence for resolving taxonomic relationships at the species level of Bryaceae.展开更多
[Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16（45） orthogonal experimental design was adopted for optimization of five important fac...[Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16（45） orthogonal experimental design was adopted for optimization of five important factors affecting PCR reaction system for random single-stranded DNA pool including Mg2＋ concentration, dNTP concentration, amount of Taq DNA polymerase, primer concentration and amount of random single-stranded DNA pool at four levels. Meanwhile, the annealing temperature and number of PCR reaction cycles were optimized to establish the optimal reaction system and PCR procedure. [Result] The optimal combination of PCR reaction system for random ssDNA pool was obtained, with a total system volume of 20 μl containing 2.0 μl of 10 × Buffer, 0.5 ng of random ssDNA pool, 2.5 mmol/L Mg2＋, 0.25 mmol/L dNTP Mixture, 0.6 μmol/L upstream and downstream primers and 1.5 U of Taq DNA polymerase; the optimal annealing temperature was 68 ℃ and the optimal number of cycles was 12. Under the above conditions, clear and stable bands with high specificity for random ssDNA pool were amplified. [Conclusion] This study laid the foundation for selection of parameters with higher specificity in SELEX technology.展开更多
Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesi...Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this work.In this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting reagent.The effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal conditions.Due to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was proposed.The results of the study may provide useful guidance for industrial production of daidzein on a large scale.展开更多
[Objective] This study aimed to establish a high-efficiency and stable SSR amplification system and screen polymorphic primers in order to further compare the tri-group probability analysis method and traditional QTL ...[Objective] This study aimed to establish a high-efficiency and stable SSR amplification system and screen polymorphic primers in order to further compare the tri-group probability analysis method and traditional QTL mapping method. [Method] In this study, we preliminarily screened the 605 pairs of primers evenly distributed on the 12 chromosomes through investigating their polymorphism performance in amplification, and established an optimized SSR-PCR reaction system. [Result] A 10μL SSR-PCR reaction system suitable for rice was set up as fol ows： 2 μl of 10 × Buffer, 2.0 mmol/L Mg2＋ （final concentration）, 0.5 mmol/L dNTPs, 1.0 μmol/L primers （final concentration）, 1 μl of DNA template, 0.15 U Taq DNA polymerase. Among the SSR primers distributed over the genome, 142 pairs that were polymorphic upon the parents were screened. [Conclusion] This study lays a good foundation for sub-sequent QTL mapping studies.展开更多
An optimization study on the amination reaction of epoxy polyisobutylene for synthesis of polyisobutylene amine is presented. The experimental results indicate that n-butanol and ethylenediamine are the suitable solve...An optimization study on the amination reaction of epoxy polyisobutylene for synthesis of polyisobutylene amine is presented. The experimental results indicate that n-butanol and ethylenediamine are the suitable solvent and amination agents for the reaction, respectively. The reaction yield of the amination reaction is notably increased with the enhanced molar ratio of either n-butanol against epoxy polyisobutylene or ethylenediamine against epoxy polyisobutylene. Also, the yield is enhanced with increasing temperature and time during the experimental range. Strikingly, the yield reaches as high as 91. 30% under optimal conditions; with the molar ratio of ethylenediamine, n-butanol and PIBO of 10∶ 6∶ 1, the reaction temperature of 150 ℃ and the reaction time of 6 h. In addition, the yield of the reaction is slightly decreased with the enhanced water content of the system. Accordingly, the mass concentration of water should be controlled within 1. 7% during the reaction.展开更多
At present,many countries are becoming more and more stringent in terms of sulfur content in fuel oil.S Zorb is a kind of desulfurization technology with advantages of exceptional desulfurization efficiency and small ...At present,many countries are becoming more and more stringent in terms of sulfur content in fuel oil.S Zorb is a kind of desulfurization technology with advantages of exceptional desulfurization efficiency and small impact on octane number.To meet the needs of environmental requirements and the trend of digitalization in the petrochemical industry,a first-principle model of S Zorb was established based on industry data.In order to describe the desulfurization and the other side reactions,a reaction network was designed and the kinetic parameters were estimated by the particle swarm optimization algorithm.Two hybrid models based on the first-principle model and support vector regression method were established to correct the mass fraction of sulfur and predict the research octane number of the refined gasoline respectively.The results indicate that the hybrid models can predict the mass fraction of PIONA,sulfur content and research octane number of the refined gasoline accurately,of which the mean absolute percentage errors are less than 6%.Hybrid models were then applied to optimize the decision variables to minimize the research octane number loss.Optimization results show that the average reduction of the loss of research octane number is 21.8%,which suggests that the models developed hold promise for guiding practical production.展开更多
[Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors（dNTPs,primers,Taq pol...[Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors（dNTPs,primers,Taq polymerase and DNA template） in PCR reaction system.[Result] The optimal reaction system obtained by orthogonal design was 25 μl in total volume,containing 2.5 μl of 10×PCR buffer solution（include MgCl2）,2.5 μl of 10 mmol/L dNTPs,2 μl（100 ng） of DNA template,2 μl of 10 μmol/L primers,0.4 μl（5 U） of Taq polymerase;the optimum annealing temperature was 34 ℃.[Conclusion] Orthogonal design was an effective method for the optimization of RAPD-PCR reaction system for G.uralensis.展开更多
This work investigates a multi-product parallel disassembly line balancing problem considering multi-skilled workers.A mathematical model for the parallel disassembly line is established to achieve maximized disassemb...This work investigates a multi-product parallel disassembly line balancing problem considering multi-skilled workers.A mathematical model for the parallel disassembly line is established to achieve maximized disassembly profit and minimized workstation cycle time.Based on a product’s AND/OR graph,matrices for task-skill,worker-skill,precedence relationships,and disassembly correlations are developed.A multi-objective discrete chemical reaction optimization algorithm is designed.To enhance solution diversity,improvements are made to four reactions:decomposition,synthesis,intermolecular ineffective collision,and wall invalid collision reaction,completing the evolution of molecular individuals.The established model and improved algorithm are applied to ball pen,flashlight,washing machine,and radio combinations,respectively.Introducing a Collaborative Resource Allocation(CRA)strategy based on a Decomposition-Based Multi-Objective Evolutionary Algorithm,the experimental results are compared with four classical algorithms:MOEA/D,MOEAD-CRA,Non-dominated Sorting Genetic Algorithm Ⅱ(NSGA-Ⅱ),and Non-dominated Sorting Genetic Algorithm Ⅲ(NSGA-Ⅲ).This validates the feasibility and superiority of the proposed algorithm in parallel disassembly production lines.展开更多
In order to establish an HPLC-MS/MS method for detecting progesterone in raw milk,raw milk was extracted with methanol,and then determined by HPLC-MS/MS after the purification with a C18 solid phase extraction column....In order to establish an HPLC-MS/MS method for detecting progesterone in raw milk,raw milk was extracted with methanol,and then determined by HPLC-MS/MS after the purification with a C18 solid phase extraction column. Qualitative determination was performed according to retention time and selective ion abundance ratio,and quantification was performed by external standard method. The results showed that progesterone had a good linear relation in the range of0. 1-5. 0 ng/ml,with a correlation coefficient of 0. 999 9. The detection limit of the established method was 0. 02 μg/kg,and the quantification limit was0. 04 μg/kg. In the standard addition range of 0. 1-5. 0 ng/ml,the recovery ranged from 79. 6% to 105. 1%,with relative standard deviation≤8. 9%. Compared with the industry standard,the detection limit and the quantification limit of the established method are significantly reduced,and the sensitivity of the method is enhanced,so this method is suitable for the detection of progesterone residue in fresh milk in pastures.展开更多
Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus....Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus.A comparison of model results with industrial data and previously reported results showed that the model can predict the process kinetics more accurately.In addition,the validated model was used to study the effects of different process variables,including coil outlet temperature(COT),steam-to-ethane ratio and residence time on ethane conversion,ethylene selectivity,products yields,and coking rate.Finally,steady-state optimization was conducted to the operation of industrial reactor.The COT and steam-to-ethane ratio were taken as decision variables to maximize the annual operational profit.展开更多
In this study,biodiesel fuel was produced from rapeseed oil via transesterification method.The optimum reaction conditions were determined by varying alcohol type and its concentration considering their influence on t...In this study,biodiesel fuel was produced from rapeseed oil via transesterification method.The optimum reaction conditions were determined by varying alcohol type and its concentration considering their influence on the yield and properties of produced biodiesel.Methanol and ethanol were alcohol used in the transesterification process.The density of biodiesel was measured at 15℃according to EN ISO 12185 test method and its viscosity was determined at 40℃by using a Brookfield digital viscometer(DV-II+Pro).Shimadzu Auto-Calculating Bomb calorimeter CA-4AJ was used to measure the high heating value.The optimum transesterification conditions found were alcohol:oil ratio of 18:1,1%of potassium hydroxide as catalyst,60 min of reaction time,60℃of reaction temperature and stirring speed of 650 rpm.Biodiesel properties under these conditions satisfied the regulatory standards and are slightly similar to those of mineral diesel tested in same conditions.Using methanol gives better results compared to ethanol.展开更多
Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and...Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.展开更多
A kind of Fe-polysilicate polymer, poly-silicic-ferric （PSF） coagulant was prepared by co-polymerization （hydroxylation of mixture of Fe^3＋ and fresh polysilicic acid （PS））, in which PSF0.5, PSF1 or PSF3 denote...A kind of Fe-polysilicate polymer, poly-silicic-ferric （PSF） coagulant was prepared by co-polymerization （hydroxylation of mixture of Fe^3＋ and fresh polysilicic acid （PS））, in which PSF0.5, PSF1 or PSF3 denotes Si/Fe molar ratio of 0.5, 1 or 3, respectively. The effects of Si/Fe ratio and reaction time （co-polymerization time or aging time） on the reaction mode between Si and Fe were studies, and the optimal species of PSF was evaluated by pH change during the preparation of PSF and coagulation tests. The results showed that the characteristics of PSF are largely affected by both reaction time and Si/Fe ratio. PSF is found to be a essential complex of Si, Fe, and many other ions. The reaction mode between Si and Fe differs with various Si/Fe ratios. The pH of PSF0.5, PSF1 or PSF3 tended to be stable when reaction time is 10, 25 or 55 rain, respectively, which is almost consistent with the time reaching the relative stable morphology that is just the optimal species of higher coagulation efficiency. The optimal reaction time reaching optimal species can be evaluated by measuring the pH change during the polymerization process.展开更多
Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the c...Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang＇an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.展开更多
In the cooling crystallization process of thiourea,a significant issue is the excessively wide crystal size distribution(CSD)and the abundance of fine crystals.This investigation delves into the growth kinetics and me...In the cooling crystallization process of thiourea,a significant issue is the excessively wide crystal size distribution(CSD)and the abundance of fine crystals.This investigation delves into the growth kinetics and mechanisms governing thiourea crystals during the cooling crystallization process.The fitting results indicate that the crystal growth rate coefficient,falls within the range of 10^(-7)to 10^(-8)m·s^(-1).Moreover,with decreasing crystallization temperature,the growth process undergoes a transition from diffusion-controlled to surface reaction-controlled,with temperature primarily influencing the surface reaction process and having a limited impact on the diffusion process.Comparing the crystal growth rate,and the diffusion-limited growth rate,at different temperatures,it is observed that the crystal growth process can be broadly divided into two stages.At temperatures above 25℃,1/qd(qd is diffusion control index)approaches 1,indicating the predominance of diffusion control.Conversely,at temperatures below 25℃,1/qd increases rapidly,signifying the dominance of surface reaction control.To address these findings,process optimization was conducted.During the high-temperature phase(35-25℃),agitation was increased to reduce the limitations posed by bulk-phase diffusion in the crystallization process.In the low-temperature phase(25-15℃),agitation was reduced to minimize crystal breakage.The optimized process resulted in a thiourea crystal product with a particle size distribution predominantly ranging from 0.7 to 0.9 mm,accounting for 84%of the total.This study provides valuable insights into resolving the issue of excessive fine crystals in the thiourea crystallization process.展开更多
基金Supported by National Scientific and Technical Supporting Project ofStudies on Superior Species Selecting and Breeding Technique ofJatropha curcasLinn(2007BAD50B01)~~
文摘[ Objective] The aim of this study was to establish the optimum cpSSR-PCR system for Jatropha curcas Linn. [ Method] cpSSR-PCR amplification system for Jatropha curcas Linn influenced by five factors including Taq DNA polymerase, Mg^2＋ , DNA template, dNTP and primer were optimized from several levels. [ Result] The optimum concentration of 20 μl reaction system was 10 × Buffer, 2.00 mmol/L Mg^2＋ , 2 U/μl Taq DNA polymerase, 0.2 mmol/L dNTP, 0.2 μmol/L primer and 35 ng/μl DNA template. [ Conclusion] The optimum annealing temperature for cpSSR-PCR reaction system is 52 ℃, and the cpSSR reaction system is steady and reproducible.
基金Supported by Young Academic Backbone Support Program of Heilongjiang Province(1152G047)Student Innovation Project of Mudanjiang Normal University~~
文摘[Objective] The aim was to establish the optimal rye-specific PCR reaction system for rye.[Method] The ordinary wheat ＂Chinese Spring＂,S165,rye,octoploid triticale and hexaploid triticale were used as materials to carry out study on the effect of the amount of template DNA,primers,dNTPs,Mg2＋ concentrations,Taq DNA polymerase and annealing temperature on the rye-specific PCR reaction system of rye.[Result] The genomic DNA extracted by modified CTAB DNA extraction method showed high quality,which was satisfied for the PCR reaction template.The rye-specific PCR reaction system was 25 μl,including 10 × buffer solution,1.5 mmol/L MgCl2,200 μmol/L dNTP,40 ng primers,40-60 ng DNA template and 1 U Taq DNA polymerase.[Conclusion] The optimal rye-specific PCR reaction system was established,which provided basis for the identification of exogenous germplasm of rye in wheat background.
文摘[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.
文摘[Objective] This research aimed to search a best method for extracting the genomic DNA of Cymbidium ensifolium and establish the optimized ISSR-PCR reaction system.[Method] Genomic DNA was extracted from C.ensifolium leaves by modified CTAB method.ISSR-PCR reaction system for C.ensifolium was optimized.[Result] High-quality genomic DNA was obtained from C.ensifolium.The 25 μl optimized ISSR-PCR reaction system for C.ensifolium contained 2.5 μl 10× PCR buffer,2.5 mmol/L MgCl2,240 ng template DNA,160 μmol/L dNTPs,1.25 U Taq DNA polymerase,0.4 μmol/L primer and 15.78 μl ddH2O.The optimal PCR procedures were：94 ℃ pre-denaturation for 5 min and then 40 cycles,94 ℃ denaturation for 30 s,50-60 ℃ annealing for 30 s （annealing temperature according to different primers）,72 ℃ extension for 50 s and a 72 ℃ extension for 7 min.[Conclusion] An optimized ISSR-PCR reaction system for C.ensifolium was established,which provides a basis for further study on genetic diversity of C.ensifolium by using ISSR molecular marker technique.
基金Supported by a Program from the State Environmental Protection Administration(20061A0013)~~
文摘[Objective] By using the genomic DNA of Cymbidium faberi Rolfe as template,the factors that affect the result of ISSR-PCR reaction system were researched and the optimal system was established.[Method] The genomic DNA was extracted from C.faberi Rolfe with method of modified CTAB.Different factors which affected ISSR amplification reaction were optimized.[Result] High-quality genomic DNA was obtained from C.faberi Rolfe.And the optimal reaction system was as follows：25 μl amplification reactions system contained 2.5 μl 10 × PCR buffer,2.0 mmol/L MgCl2,60 ng template DNA,160 μmol/L dNTPs,1.25 U Taq DNA polymerase,0.4 μmol/L ISSR primer and 15.85 μl ddH2O.The optimal amplification procedures were pre-denaturing for 5 min at 94 ℃,followed by 40 cycles of denaturing for 30 s at 94 ℃,annealing for 30 s at a temperature of 2-3 ℃ lower than melting temperature of each primer pair,extension for 50 s at 72 ℃.Then extension step of 7 min at 72 ℃ was performed.[Conclusion] The optimal system could provide a favorable basis for further study on genetic diversity of C.faberi Rolfe by using ISSR molecular marker technique.
基金Supported by Natural Science Foundation of Hebei Province(C2006000147)Zhengzhou Science and Technology Program(10PTGN449-6)~~
文摘[Objective] The aim was to provide molecular basis for the identification of species in the moss family Bryaceae by the construction of inter-simple sequence repeats （ISSR） fingerprinting. [Method] In order to seek standardizing PCR reaction set-up, an orthogonal design was used to optimize ISSR-PCR amplification system of Bryaceae in five factors （Mg2＋, dNTPs, primer, DNA template, Taq DNA polymerase） at four levels respectively. [Result] A suitable ISSR reaction system was obtained, namely： 20 μl reaction system containing 5 ng of DNA template, 0.2 μmol/L primer, 2.25 mmol/L MgCl2, 0.6 U of Taq DNA polymerase, 0.4 mmol/L dNTPs. Proper annealing temperature was found at 48-50 ℃.The above system and six ISSR-PCR primers were used for the PCR amplification of 14 samples from Bryaceae and the related species in Mniaceae. A total of 86 bands were amplified, all showed polymorphism. NJ cluster analysis showed a star-shaped cladogram. [Conclusion] The results manifested that ISSR fingerprinting could provide the appropriate degree of polymorphism at low taxonomic level, so it would be a useful tool to provide additional evidence for resolving taxonomic relationships at the species level of Bryaceae.
基金Supported by Central University Basic Research Operating Expenses Special Fund(XDJK2011C026)Southwest University Doctoral Fund(09BSR04)~~
文摘[Objective] This study aimed to optimize the PCR amplification conditions for random ssDNA pool in SELEX technology. [Method] L16（45） orthogonal experimental design was adopted for optimization of five important factors affecting PCR reaction system for random single-stranded DNA pool including Mg2＋ concentration, dNTP concentration, amount of Taq DNA polymerase, primer concentration and amount of random single-stranded DNA pool at four levels. Meanwhile, the annealing temperature and number of PCR reaction cycles were optimized to establish the optimal reaction system and PCR procedure. [Result] The optimal combination of PCR reaction system for random ssDNA pool was obtained, with a total system volume of 20 μl containing 2.0 μl of 10 × Buffer, 0.5 ng of random ssDNA pool, 2.5 mmol/L Mg2＋, 0.25 mmol/L dNTP Mixture, 0.6 μmol/L upstream and downstream primers and 1.5 U of Taq DNA polymerase; the optimal annealing temperature was 68 ℃ and the optimal number of cycles was 12. Under the above conditions, clear and stable bands with high specificity for random ssDNA pool were amplified. [Conclusion] This study laid the foundation for selection of parameters with higher specificity in SELEX technology.
基金the Science and Technology Planning Project of Guangdong Province(2016B090934002)Guangdong Provincial Natural Science Foundation(2023A1515011640)for financial support.
文摘Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,etc.Its preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this work.In this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting reagent.The effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal conditions.Due to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was proposed.The results of the study may provide useful guidance for industrial production of daidzein on a large scale.
基金Supported by the Governor Special Fund for Excellent Talents for Education of Science and Technology of Guizhou Province(2012093025)~~
文摘[Objective] This study aimed to establish a high-efficiency and stable SSR amplification system and screen polymorphic primers in order to further compare the tri-group probability analysis method and traditional QTL mapping method. [Method] In this study, we preliminarily screened the 605 pairs of primers evenly distributed on the 12 chromosomes through investigating their polymorphism performance in amplification, and established an optimized SSR-PCR reaction system. [Result] A 10μL SSR-PCR reaction system suitable for rice was set up as fol ows： 2 μl of 10 × Buffer, 2.0 mmol/L Mg2＋ （final concentration）, 0.5 mmol/L dNTPs, 1.0 μmol/L primers （final concentration）, 1 μl of DNA template, 0.15 U Taq DNA polymerase. Among the SSR primers distributed over the genome, 142 pairs that were polymorphic upon the parents were screened. [Conclusion] This study lays a good foundation for sub-sequent QTL mapping studies.
基金The Natural Science Foundation of Jiangsu Province(No.BK20130602)the Project of the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘An optimization study on the amination reaction of epoxy polyisobutylene for synthesis of polyisobutylene amine is presented. The experimental results indicate that n-butanol and ethylenediamine are the suitable solvent and amination agents for the reaction, respectively. The reaction yield of the amination reaction is notably increased with the enhanced molar ratio of either n-butanol against epoxy polyisobutylene or ethylenediamine against epoxy polyisobutylene. Also, the yield is enhanced with increasing temperature and time during the experimental range. Strikingly, the yield reaches as high as 91. 30% under optimal conditions; with the molar ratio of ethylenediamine, n-butanol and PIBO of 10∶ 6∶ 1, the reaction temperature of 150 ℃ and the reaction time of 6 h. In addition, the yield of the reaction is slightly decreased with the enhanced water content of the system. Accordingly, the mass concentration of water should be controlled within 1. 7% during the reaction.
基金supported by the National Natural Science Foundation of China(Basic Science Center Program:61988101)the Shanghai Committee of Science and Technology,China(22DZ1101500)+1 种基金Major Program of Qingyuan Innovation Laboratory(00122002)Fundamental Research Funds for the Central Universities(222202417006).
文摘At present,many countries are becoming more and more stringent in terms of sulfur content in fuel oil.S Zorb is a kind of desulfurization technology with advantages of exceptional desulfurization efficiency and small impact on octane number.To meet the needs of environmental requirements and the trend of digitalization in the petrochemical industry,a first-principle model of S Zorb was established based on industry data.In order to describe the desulfurization and the other side reactions,a reaction network was designed and the kinetic parameters were estimated by the particle swarm optimization algorithm.Two hybrid models based on the first-principle model and support vector regression method were established to correct the mass fraction of sulfur and predict the research octane number of the refined gasoline respectively.The results indicate that the hybrid models can predict the mass fraction of PIONA,sulfur content and research octane number of the refined gasoline accurately,of which the mean absolute percentage errors are less than 6%.Hybrid models were then applied to optimize the decision variables to minimize the research octane number loss.Optimization results show that the average reduction of the loss of research octane number is 21.8%,which suggests that the models developed hold promise for guiding practical production.
基金Supported by Key Projects in the National Science&Technology Pillar Program in the Eleventh Five-year Plan Period(2006BAI06A15-11)~~
文摘[Objective] The aim was to obtain the optimum RAPD-PCR reaction system for Glycyrrhiza uralensis.[Method] Orthogonal design was adopted to screen the suitable concentration of four major factors（dNTPs,primers,Taq polymerase and DNA template） in PCR reaction system.[Result] The optimal reaction system obtained by orthogonal design was 25 μl in total volume,containing 2.5 μl of 10×PCR buffer solution（include MgCl2）,2.5 μl of 10 mmol/L dNTPs,2 μl（100 ng） of DNA template,2 μl of 10 μmol/L primers,0.4 μl（5 U） of Taq polymerase;the optimum annealing temperature was 34 ℃.[Conclusion] Orthogonal design was an effective method for the optimization of RAPD-PCR reaction system for G.uralensis.
文摘This work investigates a multi-product parallel disassembly line balancing problem considering multi-skilled workers.A mathematical model for the parallel disassembly line is established to achieve maximized disassembly profit and minimized workstation cycle time.Based on a product’s AND/OR graph,matrices for task-skill,worker-skill,precedence relationships,and disassembly correlations are developed.A multi-objective discrete chemical reaction optimization algorithm is designed.To enhance solution diversity,improvements are made to four reactions:decomposition,synthesis,intermolecular ineffective collision,and wall invalid collision reaction,completing the evolution of molecular individuals.The established model and improved algorithm are applied to ball pen,flashlight,washing machine,and radio combinations,respectively.Introducing a Collaborative Resource Allocation(CRA)strategy based on a Decomposition-Based Multi-Objective Evolutionary Algorithm,the experimental results are compared with four classical algorithms:MOEA/D,MOEAD-CRA,Non-dominated Sorting Genetic Algorithm Ⅱ(NSGA-Ⅱ),and Non-dominated Sorting Genetic Algorithm Ⅲ(NSGA-Ⅲ).This validates the feasibility and superiority of the proposed algorithm in parallel disassembly production lines.
基金Supported by Science and Technology Open Cooperation Project of Henan Province(162106000017)Science and Technology People-benefiting Plan Project of Henan Province(152207110004)+1 种基金Major Science and Technology Program of Henan Province(16110051020)Puyang Science and Technology Plan Project(160215)
文摘In order to establish an HPLC-MS/MS method for detecting progesterone in raw milk,raw milk was extracted with methanol,and then determined by HPLC-MS/MS after the purification with a C18 solid phase extraction column. Qualitative determination was performed according to retention time and selective ion abundance ratio,and quantification was performed by external standard method. The results showed that progesterone had a good linear relation in the range of0. 1-5. 0 ng/ml,with a correlation coefficient of 0. 999 9. The detection limit of the established method was 0. 02 μg/kg,and the quantification limit was0. 04 μg/kg. In the standard addition range of 0. 1-5. 0 ng/ml,the recovery ranged from 79. 6% to 105. 1%,with relative standard deviation≤8. 9%. Compared with the industry standard,the detection limit and the quantification limit of the established method are significantly reduced,and the sensitivity of the method is enhanced,so this method is suitable for the detection of progesterone residue in fresh milk in pastures.
基金The financial support provided by the Project of National Natural Science Foundation of China(21822809&21978256)the Fundamental Research Funds for the Central Universitiesthe Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(Grant No.2018-K23)are gratefully acknowledged.
文摘Ethane steam cracking process in an industrial reactor was investigated.An one-demsional(1D)steady-state model was developed firstly by using an improved molecular reaction scheme and was then simulated in Aspen Plus.A comparison of model results with industrial data and previously reported results showed that the model can predict the process kinetics more accurately.In addition,the validated model was used to study the effects of different process variables,including coil outlet temperature(COT),steam-to-ethane ratio and residence time on ethane conversion,ethylene selectivity,products yields,and coking rate.Finally,steady-state optimization was conducted to the operation of industrial reactor.The COT and steam-to-ethane ratio were taken as decision variables to maximize the annual operational profit.
文摘In this study,biodiesel fuel was produced from rapeseed oil via transesterification method.The optimum reaction conditions were determined by varying alcohol type and its concentration considering their influence on the yield and properties of produced biodiesel.Methanol and ethanol were alcohol used in the transesterification process.The density of biodiesel was measured at 15℃according to EN ISO 12185 test method and its viscosity was determined at 40℃by using a Brookfield digital viscometer(DV-II+Pro).Shimadzu Auto-Calculating Bomb calorimeter CA-4AJ was used to measure the high heating value.The optimum transesterification conditions found were alcohol:oil ratio of 18:1,1%of potassium hydroxide as catalyst,60 min of reaction time,60℃of reaction temperature and stirring speed of 650 rpm.Biodiesel properties under these conditions satisfied the regulatory standards and are slightly similar to those of mineral diesel tested in same conditions.Using methanol gives better results compared to ethanol.
基金supported by the National Natural Science Foundation of China(51872115,12234018 and 52101256)Beijing Synchrotron Radiation Facility(BSRF,4B9A)。
文摘Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic performance.For the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of interaction.Herein,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery performance.The introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic activity.Our discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.
基金Project supported by the National Basic Research Projects (973) of China(No.2004CB418500).
文摘A kind of Fe-polysilicate polymer, poly-silicic-ferric （PSF） coagulant was prepared by co-polymerization （hydroxylation of mixture of Fe^3＋ and fresh polysilicic acid （PS））, in which PSF0.5, PSF1 or PSF3 denotes Si/Fe molar ratio of 0.5, 1 or 3, respectively. The effects of Si/Fe ratio and reaction time （co-polymerization time or aging time） on the reaction mode between Si and Fe were studies, and the optimal species of PSF was evaluated by pH change during the preparation of PSF and coagulation tests. The results showed that the characteristics of PSF are largely affected by both reaction time and Si/Fe ratio. PSF is found to be a essential complex of Si, Fe, and many other ions. The reaction mode between Si and Fe differs with various Si/Fe ratios. The pH of PSF0.5, PSF1 or PSF3 tended to be stable when reaction time is 10, 25 or 55 rain, respectively, which is almost consistent with the time reaching the relative stable morphology that is just the optimal species of higher coagulation efficiency. The optimal reaction time reaching optimal species can be evaluated by measuring the pH change during the polymerization process.
基金financially supported by the National Natural Science Foundation of China(Grant No.51308012)the Key Laboratory of Transportation Tunnel Engineering+1 种基金Ministry of EducationSouthwest Jiaotong University(Grant No.TTE2014-06)
文摘Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang＇an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general.
基金supported by Priority Academic Program Development of Jiangsu Higher Educatior(PPZY2015A044).
文摘In the cooling crystallization process of thiourea,a significant issue is the excessively wide crystal size distribution(CSD)and the abundance of fine crystals.This investigation delves into the growth kinetics and mechanisms governing thiourea crystals during the cooling crystallization process.The fitting results indicate that the crystal growth rate coefficient,falls within the range of 10^(-7)to 10^(-8)m·s^(-1).Moreover,with decreasing crystallization temperature,the growth process undergoes a transition from diffusion-controlled to surface reaction-controlled,with temperature primarily influencing the surface reaction process and having a limited impact on the diffusion process.Comparing the crystal growth rate,and the diffusion-limited growth rate,at different temperatures,it is observed that the crystal growth process can be broadly divided into two stages.At temperatures above 25℃,1/qd(qd is diffusion control index)approaches 1,indicating the predominance of diffusion control.Conversely,at temperatures below 25℃,1/qd increases rapidly,signifying the dominance of surface reaction control.To address these findings,process optimization was conducted.During the high-temperature phase(35-25℃),agitation was increased to reduce the limitations posed by bulk-phase diffusion in the crystallization process.In the low-temperature phase(25-15℃),agitation was reduced to minimize crystal breakage.The optimized process resulted in a thiourea crystal product with a particle size distribution predominantly ranging from 0.7 to 0.9 mm,accounting for 84%of the total.This study provides valuable insights into resolving the issue of excessive fine crystals in the thiourea crystallization process.
