[Objective] The research aimed to study the optimization conditions of RAPD reaction system of Taxus cuspidata.[Method] Using the leaves of Taxus cuspidata as materials,DNA was extracted by using modified CTAB method....[Objective] The research aimed to study the optimization conditions of RAPD reaction system of Taxus cuspidata.[Method] Using the leaves of Taxus cuspidata as materials,DNA was extracted by using modified CTAB method.The influences of template DNA concentration,primer concentration,dNTP concentration,Taq DNA polymerase amount and magnesium ion concentration on the amplification effects of RAPD of Taxus cuspidate were analyzed.[Result] Through analysis and comparison of various factors,the optimized reaction system was established as follows:in a total volume of 20 μl,containing 10 ng DNA,2.0 mmol/L Mg2+,0.2 mmol/L dNTPs,15 pmol/μl random primer,1.0 U Taq polymerase,2 μl 10×buffer,and the supplementary ddH2O.[Conclusion] The research provided technical support for further discussion on the related studies with the sexual identification of Taxus cuspidate.展开更多
Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thic...Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thickness of covering soil and medium of covering soil to establish a self-regulating ecosystem, the thickness of covering soil of land reclamation for plants in different living forms by synusia structure of plant below-ground habitat and medium of covering soil by ecological factors of plant below-ground habitat were studied. Synusia structure of plant below-ground habitat was recognized through investigation on structure and root of plant community, and ecological factors were determined through soil profile investigation. The thickness and medium of covering soil of land reclamation for the tree, the shrub and the herb were proposed.展开更多
Analysis of genetic main effects and genotype x environment (GE) interaction effects for brown rice weight (BRW) at four different filling stages in indica lice (Oryza sativa L.) was conducted for two-year experimenta...Analysis of genetic main effects and genotype x environment (GE) interaction effects for brown rice weight (BRW) at four different filling stages in indica lice (Oryza sativa L.) was conducted for two-year experimental data by using developmental genetic models and corresponding statistical approaches for quantitative traits of seeds in cereal crops. It was indicated that the genetic main effects and their GE interaction effects of triploid endosperm, cytoplasmic and diploid maternal plant genes were important for BRW at different filling stages of rice, especially for endosperm or maternal additive main effects and their additive interaction effects. Because of the higher additive effects and additive interaction effects for BRW at different filling stages, the better improving effects for this trait could be expected by selection in rice breeding. The results of conditional genetic variance components showed that the new expression of quantitative genes in endosperm and maternal plant for BRW was mostly found at all different filling stages of rice. The gene expression, however, was most active at the early filling stages especially for the first (1-7 d) and the second filling stages (8-14 d after flowering). The phenomena that some genes were spasmodically expressible among filling stages of rice were detected for some genetic effects especially for net cytoplasmic main effects or its interaction effects and net dominance main effects. Predicted genetic effects at different filling stages of rice showed that some parents such as V20 and Zuo 5 were better than others for improving the BRW.展开更多
The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate ov...The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m(CaSOa) : m(CuSOa) : m(Na2HPO4) : m(KH2PO4) is 150.0 : 13.8 : 2.5 : 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% (by mass) methyl lactate at 400℃ with 7.7 seconds contact time.展开更多
The synthesis of methylene diphenyl dimethylcarbamate (4,4'-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) ...The synthesis of methylene diphenyl dimethylcarbamate (4,4'-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) as dual solvent-catalyst. The influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4'-MDC synthesis reaction were investigated. In addition, the acid strength of ILs was de-termined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that [HSO3-bmim]CF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70℃, 40 min, molar ratio of nMPC/nHCHO= 10/1 and mass ratio of WILs/WMPC = 4.5/1, the yield of 4,4'-MDC based on HCHO was 89.9 % and the selectivity of 4,4'-MDC with respect to MPC was 74.9%. Besides, [HSO3-bmim]CF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.展开更多
An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [B...An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [Bmim]X to [Bmim]OH,amount of ionic liquid,molar ratio of water to ethylene carbonate,reaction tem-perature,pressure and reaction time,were investigated systematically. Excellent yield(>93%) and high selectivity(99.5%) of ethylene glycol were achieved. Under the optimum reaction conditions,the ionic liquid system could be reused at least five times and the selectivity of ethylene glycol remained higher than 99.5%.展开更多
Stress response of a tension leg platform (TLP) in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically ...Stress response of a tension leg platform (TLP) in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically simulated and also experimentally verified by a strain gage. Environmental loading and the platform's structural strength were analyzed in accordance with industrial standards, utilizing linear wave theory and the finite element method (FEM). The fast Fourier transform technique was used to calculate the stress response amplitude operators (RAO) from the records of measurements. A comparison was performed between the stress RAO of the numerical simulation and that of the actual measurements. The results indicated that the stress RAO of the numerical simulation fitted well with measured data at specified wave headings with different periods.展开更多
The applicability of a commercial Pt-Sn/Al2O3 isobutane dehydrogenation catalyst in dehydrogenation of propane was studied. Catalyst performance tests were carded out in a fixed-bed quartz reactor under different oper...The applicability of a commercial Pt-Sn/Al2O3 isobutane dehydrogenation catalyst in dehydrogenation of propane was studied. Catalyst performance tests were carded out in a fixed-bed quartz reactor under different operating conditions. Generally, as the factors improving propane conversion decrease the propylene selectivity, the optimal operating condition to maximize propylene yield is expected. The optimal condition was obtamed by the experimental design method. The investigated parameters were temperature, hydrogen/hydrocarbon (HE/HC) ratio and space velocity, being changed in three levels. Constrains such as the susceptibility of the catalyst components to sintering or phase transformation were also taken into account. Activity, selectivity and stability of the catalyst were considered as the measured response factors, while the space-time-yield (STY) was considered as the variable to be optimized due to its commercial interest. A STY of 16 mol.kg^-1.h^-1 was achieved under the optimal conditions of T= 620 ℃, H2/HC = 0.6 and, weight hourly space velocity (WHSV) = 2.2 h^-1. Single carbon-carbon bond rupture was found to be the main route for the formation of lower hydrocarbon byproducts.展开更多
Monoammonium phosphate (1 mol L-1), monopotassium phosphate (1 mol L-1) and aluminum ohloride (5×10-3 mol L-1) were used to investigate the influence of pH on the formation of NH4-taranakite and K-taranakite in s...Monoammonium phosphate (1 mol L-1), monopotassium phosphate (1 mol L-1) and aluminum ohloride (5×10-3 mol L-1) were used to investigate the influence of pH on the formation of NH4-taranakite and K-taranakite in systems with a high NH4H2PO4 or KH2PO4 concentration. The experimental data indicated that the reaction products of aluminum with NH4H2PO4 or KH2PO4 changed with the pH in the systems. In a pH range of 2.5 to 10.0, as the pH increased, the products in either ammonium or potassium system followed the sequence: taranakite, amorphous (NH4, K)2AlH(PO4)2 .4H2O, and then crystalline (NH4, K)AlPO4OH.2H2O. However, the pH ranges of the formation of these products in ammonium system were different from potassium system. NH4-taranakite formed from pH 2.75 to PH 5.75, whereas K-taranakite formed in the pH range of 3.00 to 5.00. From the theoretical calculation by a computer program (GEOCHEM version 2.0), NH4-taranakite and K-taranakite could form at the pH from 1.50 to 8.30 and from 1.25 to 8.45,respectively. These pH ranges were much wider than the experimental results. The difference between the experimental data and theoretical data was attributed to the lack of kinetic data and/or the incompleteness and inaccuracy of the thermodynamic data in the data base of the program. The PH ranges of the formation of the taranakites indicated that the taranakites could exist in the immediate vicinity of phosphate fertilizer zone as reaction products of phosphate fertilizers with soils, especially acidic soils, resulting in the fixation of not only phosphate but also nitrogen and/or potassium in soils.展开更多
To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test ...To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species responding the stress conditions in the intertidal. Absolute real-time PCR technology was applied to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species in stress responding. According to the results of photosynthesis parameters, we observed that Y(II) and Fv/Fm were significantly affected when stress was imposed on the thalli of Porphyra yezoensis, but underwent almost completely recovered under normal conditions, which were collected for the following experiments. Then three samples, which were treated with different grade stresses combined with salinity, irradiation and temperature, were collected. The transcription numbers of seven constitutive expression genes in above samples were determined after RNA extraction and cDNA synthesis. Finally, a general insight into the selection of internal control genes during stress response was obtained. We found that there were no obvious effects in terms of salinity stress (at salinity 90) on transcription of most genes used in the study. The 18S ribosomal RNA gene had the highest expression level, varying remarkably among different tested groups. RPS8 expression showed a high irregular variance between samples. GAPDH presented comparatively stable expression and could thus be selected as the internal control. EF-la showed stable expression during the series of multiple-stress tests. Our research provided available references for the selection of internal control genes for transcripts determination of P. yezoensis.展开更多
Cu(II) and Mn(II) metals embedded on mesoporous SBA-15 were synthesized by co-precipitation technique.The support and catalysts were characterized by SEM–EDX,TEM,BET,XRD and ICP-AES methods.The catalytic activity of ...Cu(II) and Mn(II) metals embedded on mesoporous SBA-15 were synthesized by co-precipitation technique.The support and catalysts were characterized by SEM–EDX,TEM,BET,XRD and ICP-AES methods.The catalytic activity of these catalysts was evaluated for styrene oxidation at various reaction conditions such as styrene to TBHP mole ratio,temperature,catalyst amount by using TBHP as an oxidizing agent.Major reaction products were styrene oxide and benzaldehyde and highest styrene conversion(97.3%) was observed at styrene to TBHP mole ratio of 1:4,temperature at 80 °C and 20 mg of catalyst.Further,the recyclability of the catalysts was observed and found that they can be recycled three times without major loss in their activity and selectivity.展开更多
Objective:To investigate the characteristics of fat metabolism in rat skeletal muscle after hypobaric hypoxia acclimation. Methods: Sprague-Dawley rats were divided into 3 groups randomly: control group (H0), hyp...Objective:To investigate the characteristics of fat metabolism in rat skeletal muscle after hypobaric hypoxia acclimation. Methods: Sprague-Dawley rats were divided into 3 groups randomly: control group (H0), hypoxic 5-day group (HS), and hypoxic 15-day group (H15). Animals of H5 and 15 groups were exposed to hypobaric hypoxia chamber simulating 5 000 m high altitude for 5 d or 15 d respectively, 23 h per day. H0 group stayed outside of chamber The level of fatty acid oxidation and uptake, and glucose oxidation were examined, and the level of non-esterified fatty acids (NEFA), ATP and phosphocreatine (PCr) were also assayed in rat skeletal muscles. Results: The contents of ATP and PCr in H5 group were lower than those in H0 and H15 groups (P〈0.05), while there was no significant difference between H0 and H15. Compared with H0, the blood NEFA level in all hypoxia groups was increased significantly (P〈0.05). The muscle NEFA level in H15 group was greatly higher than that in H0 and H5 groups. The rates of fatty acid oxidation and uptake in H15 group were significantly higher than those in H0 and H5 groups (P〈0.05), and the rate of glucose oxidation in all hypoxia groups was significantly decreased than that in H0 group (P〈0.05). Conclusion: It is concluded that the enhanced fat oxidation may be one of the mechanisms in the maintenance of energy homeostasis after hypobaric hypoxic acclimation.展开更多
Pjridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield ...Pjridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield of pyridine and 3-picoline decreased, but the selectivity of pyridine over 3-picoline increased compared to turbulent fluidized-bed reactor. Based on experimental data, a modified kinetic model was used for the determination of optimal operating condition for riser reactor. The optimal operating condition of riser reactor given by this modified model was as follows: The reaction temperature of 755 K, catalyst to feedstock ratio (CTFR) of 87, residence timeof3.8sandinitialacetaldehydesconcentrationof0.0029mol.L-1 (acetaldehydes to formaldehydes ratio by mole (ATFR) of 0.65 and ammonia to aldehydes ratio by mole (ATAR) of 0.9, water contention of 63wt% (formaldehyde solution)).展开更多
The alkylation of p-cresol with tert-butanol(TBA)to 2-tert-butyl-p-cresol(TBC)catalyzed by a novel multiple-SO3H functioned ionic liquid(IL1)was investigated.Meanwhile,the catalytic activity of this novel ionic ...The alkylation of p-cresol with tert-butanol(TBA)to 2-tert-butyl-p-cresol(TBC)catalyzed by a novel multiple-SO3H functioned ionic liquid(IL1)was investigated.Meanwhile,the catalytic activity of this novel ionic liquid was compared with other four traditional ionic liquids.The results showed that IL1 has superior catalytic activity to other four traditional ionic liquids with the conversion of 85.3%and selectivity of 95.2%.Also,the reaction conditions were investigated to obtain the optimum conditions.Operational simplicity,small amount of usage,high activity,reusability and selectivity are the key features of this methodology.展开更多
Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral...Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.展开更多
文摘[Objective] The research aimed to study the optimization conditions of RAPD reaction system of Taxus cuspidata.[Method] Using the leaves of Taxus cuspidata as materials,DNA was extracted by using modified CTAB method.The influences of template DNA concentration,primer concentration,dNTP concentration,Taq DNA polymerase amount and magnesium ion concentration on the amplification effects of RAPD of Taxus cuspidate were analyzed.[Result] Through analysis and comparison of various factors,the optimized reaction system was established as follows:in a total volume of 20 μl,containing 10 ng DNA,2.0 mmol/L Mg2+,0.2 mmol/L dNTPs,15 pmol/μl random primer,1.0 U Taq polymerase,2 μl 10×buffer,and the supplementary ddH2O.[Conclusion] The research provided technical support for further discussion on the related studies with the sexual identification of Taxus cuspidate.
文摘Land reclamation is a process of ecosystem reconstruction, for which it is very important to keep co-adaptation between plants and the below ground habitat. In order to keep the co-adaptation among plant species, thickness of covering soil and medium of covering soil to establish a self-regulating ecosystem, the thickness of covering soil of land reclamation for plants in different living forms by synusia structure of plant below-ground habitat and medium of covering soil by ecological factors of plant below-ground habitat were studied. Synusia structure of plant below-ground habitat was recognized through investigation on structure and root of plant community, and ecological factors were determined through soil profile investigation. The thickness and medium of covering soil of land reclamation for the tree, the shrub and the herb were proposed.
文摘Analysis of genetic main effects and genotype x environment (GE) interaction effects for brown rice weight (BRW) at four different filling stages in indica lice (Oryza sativa L.) was conducted for two-year experimental data by using developmental genetic models and corresponding statistical approaches for quantitative traits of seeds in cereal crops. It was indicated that the genetic main effects and their GE interaction effects of triploid endosperm, cytoplasmic and diploid maternal plant genes were important for BRW at different filling stages of rice, especially for endosperm or maternal additive main effects and their additive interaction effects. Because of the higher additive effects and additive interaction effects for BRW at different filling stages, the better improving effects for this trait could be expected by selection in rice breeding. The results of conditional genetic variance components showed that the new expression of quantitative genes in endosperm and maternal plant for BRW was mostly found at all different filling stages of rice. The gene expression, however, was most active at the early filling stages especially for the first (1-7 d) and the second filling stages (8-14 d after flowering). The phenomena that some genes were spasmodically expressible among filling stages of rice were detected for some genetic effects especially for net cytoplasmic main effects or its interaction effects and net dominance main effects. Predicted genetic effects at different filling stages of rice showed that some parents such as V20 and Zuo 5 were better than others for improving the BRW.
基金he Special Foundation for State Major Basic Research Program of China(2007CB707805,2004CCA05500)
文摘The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m(CaSOa) : m(CuSOa) : m(Na2HPO4) : m(KH2PO4) is 150.0 : 13.8 : 2.5 : 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% (by mass) methyl lactate at 400℃ with 7.7 seconds contact time.
基金Supported by the National Natural Science Foundation of China (20576025). the National Key Basic Project of China (2005CCA06100), the Science and Technological Research and Development Project of Hebei Province (07215602D) and the Natural Science Foundation of Hebei Province 032007000010).
文摘The synthesis of methylene diphenyl dimethylcarbamate (4,4'-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) as dual solvent-catalyst. The influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4'-MDC synthesis reaction were investigated. In addition, the acid strength of ILs was de-termined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that [HSO3-bmim]CF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70℃, 40 min, molar ratio of nMPC/nHCHO= 10/1 and mass ratio of WILs/WMPC = 4.5/1, the yield of 4,4'-MDC based on HCHO was 89.9 % and the selectivity of 4,4'-MDC with respect to MPC was 74.9%. Besides, [HSO3-bmim]CF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.
基金Supported by the National High Technology Research and Development Program of China(2006AA06Z317) National Natural Science Foundation of China(20876162)+3 种基金 National Basic Research Program of China(2009CB219901) National Key Technology Research and Development Program(2008BAF33B04) National Science Fund of China(21006117) Science and Technology Project of Beijing(Y090081135)
文摘An ionic liquid system of [Bmim]X/[Bmim]OH(X Cl,BF4,and PF6,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [Bmim]X to [Bmim]OH,amount of ionic liquid,molar ratio of water to ethylene carbonate,reaction tem-perature,pressure and reaction time,were investigated systematically. Excellent yield(>93%) and high selectivity(99.5%) of ethylene glycol were achieved. Under the optimum reaction conditions,the ionic liquid system could be reused at least five times and the selectivity of ethylene glycol remained higher than 99.5%.
基金supported by the Fund of "111 Project" (Grant No.B07019) from the State Administration of Foreign Experts Affairs and the Ministry of Education of China
文摘Stress response of a tension leg platform (TLP) in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically simulated and also experimentally verified by a strain gage. Environmental loading and the platform's structural strength were analyzed in accordance with industrial standards, utilizing linear wave theory and the finite element method (FEM). The fast Fourier transform technique was used to calculate the stress response amplitude operators (RAO) from the records of measurements. A comparison was performed between the stress RAO of the numerical simulation and that of the actual measurements. The results indicated that the stress RAO of the numerical simulation fitted well with measured data at specified wave headings with different periods.
基金Supported by the Petrochemical Research&Technology Co. of National Petrochemical Co.
文摘The applicability of a commercial Pt-Sn/Al2O3 isobutane dehydrogenation catalyst in dehydrogenation of propane was studied. Catalyst performance tests were carded out in a fixed-bed quartz reactor under different operating conditions. Generally, as the factors improving propane conversion decrease the propylene selectivity, the optimal operating condition to maximize propylene yield is expected. The optimal condition was obtamed by the experimental design method. The investigated parameters were temperature, hydrogen/hydrocarbon (HE/HC) ratio and space velocity, being changed in three levels. Constrains such as the susceptibility of the catalyst components to sintering or phase transformation were also taken into account. Activity, selectivity and stability of the catalyst were considered as the measured response factors, while the space-time-yield (STY) was considered as the variable to be optimized due to its commercial interest. A STY of 16 mol.kg^-1.h^-1 was achieved under the optimal conditions of T= 620 ℃, H2/HC = 0.6 and, weight hourly space velocity (WHSV) = 2.2 h^-1. Single carbon-carbon bond rupture was found to be the main route for the formation of lower hydrocarbon byproducts.
文摘Monoammonium phosphate (1 mol L-1), monopotassium phosphate (1 mol L-1) and aluminum ohloride (5×10-3 mol L-1) were used to investigate the influence of pH on the formation of NH4-taranakite and K-taranakite in systems with a high NH4H2PO4 or KH2PO4 concentration. The experimental data indicated that the reaction products of aluminum with NH4H2PO4 or KH2PO4 changed with the pH in the systems. In a pH range of 2.5 to 10.0, as the pH increased, the products in either ammonium or potassium system followed the sequence: taranakite, amorphous (NH4, K)2AlH(PO4)2 .4H2O, and then crystalline (NH4, K)AlPO4OH.2H2O. However, the pH ranges of the formation of these products in ammonium system were different from potassium system. NH4-taranakite formed from pH 2.75 to PH 5.75, whereas K-taranakite formed in the pH range of 3.00 to 5.00. From the theoretical calculation by a computer program (GEOCHEM version 2.0), NH4-taranakite and K-taranakite could form at the pH from 1.50 to 8.30 and from 1.25 to 8.45,respectively. These pH ranges were much wider than the experimental results. The difference between the experimental data and theoretical data was attributed to the lack of kinetic data and/or the incompleteness and inaccuracy of the thermodynamic data in the data base of the program. The PH ranges of the formation of the taranakites indicated that the taranakites could exist in the immediate vicinity of phosphate fertilizer zone as reaction products of phosphate fertilizers with soils, especially acidic soils, resulting in the fixation of not only phosphate but also nitrogen and/or potassium in soils.
基金Supported by the National Natural Science Foundation of China(Nos.41176134,30830015)the Prospective Joint Research Project of Jiangsu Province(No.BY2011188)+1 种基金the National Marine Public Welfare Research Project(Nos.201105008-2,201105023-7)the National Basic Research Program of China(973 Program)(No.2011CB411908)
文摘To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species responding the stress conditions in the intertidal. Absolute real-time PCR technology was applied to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species in stress responding. According to the results of photosynthesis parameters, we observed that Y(II) and Fv/Fm were significantly affected when stress was imposed on the thalli of Porphyra yezoensis, but underwent almost completely recovered under normal conditions, which were collected for the following experiments. Then three samples, which were treated with different grade stresses combined with salinity, irradiation and temperature, were collected. The transcription numbers of seven constitutive expression genes in above samples were determined after RNA extraction and cDNA synthesis. Finally, a general insight into the selection of internal control genes during stress response was obtained. We found that there were no obvious effects in terms of salinity stress (at salinity 90) on transcription of most genes used in the study. The 18S ribosomal RNA gene had the highest expression level, varying remarkably among different tested groups. RPS8 expression showed a high irregular variance between samples. GAPDH presented comparatively stable expression and could thus be selected as the internal control. EF-la showed stable expression during the series of multiple-stress tests. Our research provided available references for the selection of internal control genes for transcripts determination of P. yezoensis.
文摘Cu(II) and Mn(II) metals embedded on mesoporous SBA-15 were synthesized by co-precipitation technique.The support and catalysts were characterized by SEM–EDX,TEM,BET,XRD and ICP-AES methods.The catalytic activity of these catalysts was evaluated for styrene oxidation at various reaction conditions such as styrene to TBHP mole ratio,temperature,catalyst amount by using TBHP as an oxidizing agent.Major reaction products were styrene oxide and benzaldehyde and highest styrene conversion(97.3%) was observed at styrene to TBHP mole ratio of 1:4,temperature at 80 °C and 20 mg of catalyst.Further,the recyclability of the catalysts was observed and found that they can be recycled three times without major loss in their activity and selectivity.
基金the National Basic Research Program of China(2006CB504100)the National Natural Science Foundation of China (30393131, 30771043)
文摘Objective:To investigate the characteristics of fat metabolism in rat skeletal muscle after hypobaric hypoxia acclimation. Methods: Sprague-Dawley rats were divided into 3 groups randomly: control group (H0), hypoxic 5-day group (HS), and hypoxic 15-day group (H15). Animals of H5 and 15 groups were exposed to hypobaric hypoxia chamber simulating 5 000 m high altitude for 5 d or 15 d respectively, 23 h per day. H0 group stayed outside of chamber The level of fatty acid oxidation and uptake, and glucose oxidation were examined, and the level of non-esterified fatty acids (NEFA), ATP and phosphocreatine (PCr) were also assayed in rat skeletal muscles. Results: The contents of ATP and PCr in H5 group were lower than those in H0 and H15 groups (P〈0.05), while there was no significant difference between H0 and H15. Compared with H0, the blood NEFA level in all hypoxia groups was increased significantly (P〈0.05). The muscle NEFA level in H15 group was greatly higher than that in H0 and H5 groups. The rates of fatty acid oxidation and uptake in H15 group were significantly higher than those in H0 and H5 groups (P〈0.05), and the rate of glucose oxidation in all hypoxia groups was significantly decreased than that in H0 group (P〈0.05). Conclusion: It is concluded that the enhanced fat oxidation may be one of the mechanisms in the maintenance of energy homeostasis after hypobaric hypoxic acclimation.
基金Supported by the National Basic Research Program of China(973 Program,2012CB215000)
文摘Pjridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield of pyridine and 3-picoline decreased, but the selectivity of pyridine over 3-picoline increased compared to turbulent fluidized-bed reactor. Based on experimental data, a modified kinetic model was used for the determination of optimal operating condition for riser reactor. The optimal operating condition of riser reactor given by this modified model was as follows: The reaction temperature of 755 K, catalyst to feedstock ratio (CTFR) of 87, residence timeof3.8sandinitialacetaldehydesconcentrationof0.0029mol.L-1 (acetaldehydes to formaldehydes ratio by mole (ATFR) of 0.65 and ammonia to aldehydes ratio by mole (ATAR) of 0.9, water contention of 63wt% (formaldehyde solution)).
基金Supported by the National High Technology Research and Development Program of China(2006BAE03B06)Shanghai Leading Academic Discipline Project(B409)Shanghai International Cooperation of Science and Technology Project(06SR07101)
文摘The alkylation of p-cresol with tert-butanol(TBA)to 2-tert-butyl-p-cresol(TBC)catalyzed by a novel multiple-SO3H functioned ionic liquid(IL1)was investigated.Meanwhile,the catalytic activity of this novel ionic liquid was compared with other four traditional ionic liquids.The results showed that IL1 has superior catalytic activity to other four traditional ionic liquids with the conversion of 85.3%and selectivity of 95.2%.Also,the reaction conditions were investigated to obtain the optimum conditions.Operational simplicity,small amount of usage,high activity,reusability and selectivity are the key features of this methodology.
基金Supported by the Natural Science Foundation of Hubei Province(2008CDB354) Wuhan Youth Scientist Dawn Foundation(200750731288)
文摘Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.