The crystal structure of the title compound [Cu (o-vanillin-ethylenediamine) (H2O)] is described. The complex crystallizes in the orthorhombic system, space group Pbn21 with formula = CuC18H20N2O5, cell dimensions are...The crystal structure of the title compound [Cu (o-vanillin-ethylenediamine) (H2O)] is described. The complex crystallizes in the orthorhombic system, space group Pbn21 with formula = CuC18H20N2O5, cell dimensions are: a = 0.7490(3) nm, b = 0.9256(2) nm, c=2. 4691(6) nm, V=1.712 nm3, Z = 4, Dc=l.51 g/cm3. The kinetics of thermal decomposition of the complex was studied under the non-isothermal condition by TG. Kinetic parameters were obtained from the analysis of the TG, DTG curves by integral and differential methods. By comparison of the kinetic parameters, the most probable mechanism function is f(α) = (3/2) (1-α)[-ln(1-α)]1/3, and the mathematical expression for the kinetic compensation effect is lnA = 0. 201E+0. 531.展开更多
Introduction Complexes of some Schiff bases with transition metals are widely used, for example, they can be used as anticancer medicine, preservative, complex reagent and the model of the biological oxygen carrier. S...Introduction Complexes of some Schiff bases with transition metals are widely used, for example, they can be used as anticancer medicine, preservative, complex reagent and the model of the biological oxygen carrier. So their syntheses, properties and application have been intensively studied. In order to study the relationship between the展开更多
Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper ...Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper analyzed the degree of processing of rehmannia root(Rehmanniae radix)relative to the dynamic variation rules of Maillard reaction index parameters,including pH,A420,amino acids,and 5-hydroxymethylfurfural.Furthermore,this study introduced thermal analysis techniques and pyrolysis kinetics to assess the influence of the correlation between processing raw rehmannia root and the Maillard reaction during carbonization.It then went through the whole process of transforming the raw material to end-product in order to explain the scientific connotation of processing it.Results:The results showed that each time rehmannia root was processed,its pH value and amino acid content decreased,while the A420 value and 5-HMF increased.Processing with wine shows a significant difference in these experimental indexes.The position and intensity of the maximum thermal weight loss rate peak of processed rehmannia root at different degrees of processing are different.Comprehensive quantitative 221±0.2°C for processed rehmannia root carbonization was the processing temperature limit.Moreover,the kinetic solution verified that the activation energy corresponding to the carbonization temperature was close to the maximum value of the activation energy of the whole carbonization process,and the optimal mechanism function was g(α)=((1−α)−1/3−1)2.Conclusion:The Maillard reaction occurred during the processing of rehmannia root mixed with carbonization.With each increase of the number of steaming and drying cycles involved in the processing,the level of Maillard reaction increased significantly.The wine-steaming method had a significant effect on the quality of the processed product.展开更多
The thermal behaviour of aloe-emodin, chrysophanol and physcion and their kinetics have been investigated under non-isothermal conditions by means of differential thermal analysis （DTA） and thermogravimetry （TG）. ...The thermal behaviour of aloe-emodin, chrysophanol and physcion and their kinetics have been investigated under non-isothermal conditions by means of differential thermal analysis （DTA） and thermogravimetry （TG）. The thermal characteristics have been determined using the DTA and TG-DTG curves. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan （MKN） method. The possible reaction mechanisms have been investigated by comparing the kinetic parameters. The kinetic equation for aloe-emodin, chrysophanol and physcion can be expressed as dα/dt=Aexp（-E/RT）1/3（1-α）[-In（1-α]2. The activation energy E （kJ mol^-1） of the three free anthraquinones are 78.09, 89.54, and 107.5 and their InA/s^-1 are 22.98, 36.85 and 43.60, respectively.展开更多
By citrate sol-gel auto-combustion method,the nanophase M-type planar hexagonal ferrite is prepared.The transmission electron microscopy(TEM),X-ray diffraction(XRD) and thermal analysis are used to study the grain siz...By citrate sol-gel auto-combustion method,the nanophase M-type planar hexagonal ferrite is prepared.The transmission electron microscopy(TEM),X-ray diffraction(XRD) and thermal analysis are used to study the grain size,phase composition,microstructure and crystallization process.The results show that the nanophase M-type Sr-ferrite prepared by this method is single,and its grain size is smaller than 100 nm.Moreover,most of the grains present hexagonal sheet shape.Tests are carried out for its attenuation to 1.06 mm laser.It is found that the extinction capability of the nanophase M-type Sr-ferrite smoke is good,and its mass extinction coefficient is 1.628 m2/g.展开更多
In the research described in this paper,the uses of the urea/thiourea complexation approach were employed to enhance the octane number of FCC gasoline by extracting n-alkanes.It was observed that adding thiourea impro...In the research described in this paper,the uses of the urea/thiourea complexation approach were employed to enhance the octane number of FCC gasoline by extracting n-alkanes.It was observed that adding thiourea improved the removal of the n-alkanes from gasoline,and matching results were obtained from experiments using model samples.Molecular dynamics simulation revealed that the stability of urea complexes increased as the carbon number of the n-alkanes was raised,whereas lighter n-alkane molecules exhibited a lower propensity for complex formation with urea.This finding is in agreement with the results of the DSC measurement at the decomposition temperature.Furthermore,infrared spectrum analysis,XRD characterization,and reaction heat measurements indicated that although thiourea was introduced into the reaction system,it did not actively participate in the complexation reaction.In summary,the introduction of thiourea resulted in an increased solubility of urea in an ethanol solution and enhanced the reaction heat,suggesting its beneficial role in promoting urea complex formation and facilitating n-alkane removal from FCC gasoline.展开更多
Three vips with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-ada...Three vips with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-vip complexes of Cucurbit[n = 6—8]urils with these vips have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-vip complexes.展开更多
In diode pumped Nd：YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A...In diode pumped Nd：YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly efficient 473-nm laser. When the absorbed pump power （with 15.8-W incident pump power） at 885 nm into Nd：YAG is 10 W, a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled. The optical-to-optical conversion efficiency is 14.8%. To the best of our knowledge, this is the highest efficiency at 473 nm bv an intra-cavitv doubled freauencv Nd：YAG laser.展开更多
文摘The crystal structure of the title compound [Cu (o-vanillin-ethylenediamine) (H2O)] is described. The complex crystallizes in the orthorhombic system, space group Pbn21 with formula = CuC18H20N2O5, cell dimensions are: a = 0.7490(3) nm, b = 0.9256(2) nm, c=2. 4691(6) nm, V=1.712 nm3, Z = 4, Dc=l.51 g/cm3. The kinetics of thermal decomposition of the complex was studied under the non-isothermal condition by TG. Kinetic parameters were obtained from the analysis of the TG, DTG curves by integral and differential methods. By comparison of the kinetic parameters, the most probable mechanism function is f(α) = (3/2) (1-α)[-ln(1-α)]1/3, and the mathematical expression for the kinetic compensation effect is lnA = 0. 201E+0. 531.
文摘Introduction Complexes of some Schiff bases with transition metals are widely used, for example, they can be used as anticancer medicine, preservative, complex reagent and the model of the biological oxygen carrier. So their syntheses, properties and application have been intensively studied. In order to study the relationship between the
基金This research was funded by General Project of the National Natural Science Foundation of China(No.81673601)the Key Research&Development Plan of Shanxi Province(Social Development Project,No.201603D3112002)Cultivate Scientific Research Excellence Programs of Higher Education Institutions in Shanxi(No.2019KJ032).
文摘Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper analyzed the degree of processing of rehmannia root(Rehmanniae radix)relative to the dynamic variation rules of Maillard reaction index parameters,including pH,A420,amino acids,and 5-hydroxymethylfurfural.Furthermore,this study introduced thermal analysis techniques and pyrolysis kinetics to assess the influence of the correlation between processing raw rehmannia root and the Maillard reaction during carbonization.It then went through the whole process of transforming the raw material to end-product in order to explain the scientific connotation of processing it.Results:The results showed that each time rehmannia root was processed,its pH value and amino acid content decreased,while the A420 value and 5-HMF increased.Processing with wine shows a significant difference in these experimental indexes.The position and intensity of the maximum thermal weight loss rate peak of processed rehmannia root at different degrees of processing are different.Comprehensive quantitative 221±0.2°C for processed rehmannia root carbonization was the processing temperature limit.Moreover,the kinetic solution verified that the activation energy corresponding to the carbonization temperature was close to the maximum value of the activation energy of the whole carbonization process,and the optimal mechanism function was g(α)=((1−α)−1/3−1)2.Conclusion:The Maillard reaction occurred during the processing of rehmannia root mixed with carbonization.With each increase of the number of steaming and drying cycles involved in the processing,the level of Maillard reaction increased significantly.The wine-steaming method had a significant effect on the quality of the processed product.
文摘The thermal behaviour of aloe-emodin, chrysophanol and physcion and their kinetics have been investigated under non-isothermal conditions by means of differential thermal analysis （DTA） and thermogravimetry （TG）. The thermal characteristics have been determined using the DTA and TG-DTG curves. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan （MKN） method. The possible reaction mechanisms have been investigated by comparing the kinetic parameters. The kinetic equation for aloe-emodin, chrysophanol and physcion can be expressed as dα/dt=Aexp（-E/RT）1/3（1-α）[-In（1-α]2. The activation energy E （kJ mol^-1） of the three free anthraquinones are 78.09, 89.54, and 107.5 and their InA/s^-1 are 22.98, 36.85 and 43.60, respectively.
文摘By citrate sol-gel auto-combustion method,the nanophase M-type planar hexagonal ferrite is prepared.The transmission electron microscopy(TEM),X-ray diffraction(XRD) and thermal analysis are used to study the grain size,phase composition,microstructure and crystallization process.The results show that the nanophase M-type Sr-ferrite prepared by this method is single,and its grain size is smaller than 100 nm.Moreover,most of the grains present hexagonal sheet shape.Tests are carried out for its attenuation to 1.06 mm laser.It is found that the extinction capability of the nanophase M-type Sr-ferrite smoke is good,and its mass extinction coefficient is 1.628 m2/g.
基金The authors gratefully acknowledge the financial support from the key special project of“Inner Mongolia Revitalization Action with Science and Technology”(No.2021EEDSCXSFQZD004)from the Clean Combustion and Low-carbon Utilization of Coal Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA 29000000)。
文摘In the research described in this paper,the uses of the urea/thiourea complexation approach were employed to enhance the octane number of FCC gasoline by extracting n-alkanes.It was observed that adding thiourea improved the removal of the n-alkanes from gasoline,and matching results were obtained from experiments using model samples.Molecular dynamics simulation revealed that the stability of urea complexes increased as the carbon number of the n-alkanes was raised,whereas lighter n-alkane molecules exhibited a lower propensity for complex formation with urea.This finding is in agreement with the results of the DSC measurement at the decomposition temperature.Furthermore,infrared spectrum analysis,XRD characterization,and reaction heat measurements indicated that although thiourea was introduced into the reaction system,it did not actively participate in the complexation reaction.In summary,the introduction of thiourea resulted in an increased solubility of urea in an ethanol solution and enhanced the reaction heat,suggesting its beneficial role in promoting urea complex formation and facilitating n-alkane removal from FCC gasoline.
文摘Three vips with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-vip complexes of Cucurbit[n = 6—8]urils with these vips have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-vip complexes.
基金supported by the Foundation Research Program for National Defense Commission of Science, Technology,and Industry for National Defense of China under Grant No.A3620060122.
文摘In diode pumped Nd：YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly efficient 473-nm laser. When the absorbed pump power （with 15.8-W incident pump power） at 885 nm into Nd：YAG is 10 W, a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled. The optical-to-optical conversion efficiency is 14.8%. To the best of our knowledge, this is the highest efficiency at 473 nm bv an intra-cavitv doubled freauencv Nd：YAG laser.
