The present study introduces a screw-pressing charging method to tackle deficiencies in automation and charge uniformity during the melt-casting of polymer-based energetic materials.To ensure the safety of the experim...The present study introduces a screw-pressing charging method to tackle deficiencies in automation and charge uniformity during the melt-casting of polymer-based energetic materials.To ensure the safety of the experiments,this study used inert materials with similar physical properties to partially substitute for the actual energetic components in the preparation of simulant materials.By thoroughly analyzing slurry physical properties,a simulation framework and an extensive performance evaluation method were developed.Such tools guide the design of the structure and configuration of process parameters.Results demonstrate that employing the Pin element significantly enhances radial mixing within the screw,minimizes temperature variations in the slurry,and improves both efficiency and safety in the mixing process.Further,adjustments such as widening the cone angle of the barrel,modifying the solid content of the slurry,and varying the speed of the screw can optimize the mechanical and thermal coupling in the flow field.These adjustments promote higher-quality slurry and create a safer production environment for the extrusion process.展开更多
The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffr...The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.展开更多
The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2...The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.展开更多
A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in...A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in the triclinic.,space group P1 with ceIl parameters:a=O.90363(2)nm,b=1.25078(3)nm,c=1.41303(1)nm,穋m^(-3),Z=2,Mr=756.72,F(000)=760,Ⅲ)and the approxi-mately oriented octahedrally sixfold-coordinated Fe(Ⅲ)are linked by a cyano-bridge group to construct a dinuclear compound.The{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](Ⅲ)-Fe(Ⅲ)interaction is antiferromagnetic.CCDC:223430.展开更多
Talin-1 head(hereinafter referred to as TH)is the head structure of talin protein,which contains a four-point-one-protein/ezrin/radixin/moesin(FERM)domain.Its F1 domain contains an unstructured loop of 30 amino acids(...Talin-1 head(hereinafter referred to as TH)is the head structure of talin protein,which contains a four-point-one-protein/ezrin/radixin/moesin(FERM)domain.Its F1 domain contains an unstructured loop of 30 amino acids(139-168),which does not interact with other domains.Because TH doesn’t get the crystal structure and whether the unstructured loop has obvious influence on the TH secondary structure,therefore,the truncated talin-1 headΔ139-168(hereinafter referred to as THΔ)was constructed and its structure and the impact of stability after truncation were analyzed.Molecular biology and structural biology methods were used to construct prokaryotic expression vectors of TH and THΔ,explore and optimize the expression conditions of recombinants,and they were purified by affinity chromatography and FPLC gel filtration chromatography.Finally,a large number of stable,high-purity protein samples were prepared successfully.The physicochemical properties and structural stability of the proteins were investigated by dynamic light scattering and circular dichroism.The results showed that the THΔsecondary structure of the truncated body did not change significantly,the structural stability was enhanced and the resistance to guanidine hydrochloride and high temperature was stronger.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities(Grant No.30923011018)。
文摘The present study introduces a screw-pressing charging method to tackle deficiencies in automation and charge uniformity during the melt-casting of polymer-based energetic materials.To ensure the safety of the experiments,this study used inert materials with similar physical properties to partially substitute for the actual energetic components in the preparation of simulant materials.By thoroughly analyzing slurry physical properties,a simulation framework and an extensive performance evaluation method were developed.Such tools guide the design of the structure and configuration of process parameters.Results demonstrate that employing the Pin element significantly enhances radial mixing within the screw,minimizes temperature variations in the slurry,and improves both efficiency and safety in the mixing process.Further,adjustments such as widening the cone angle of the barrel,modifying the solid content of the slurry,and varying the speed of the screw can optimize the mechanical and thermal coupling in the flow field.These adjustments promote higher-quality slurry and create a safer production environment for the extrusion process.
文摘The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.
基金The Ministry of Science and Higher Education of the Russian Federation(Agreement with Zelinsky Institute of Organic Chemistry RAS No 075-15-2020-803).
文摘The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.
文摘A new cyano-bridged Gadolinium^(Ⅲ)-Iron^(Ⅲ)complex{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)]2H_(2)0(DMF=N,N·-dimethylformamide;DMSO=dimethylsulfoxidel}was synthesized by the grinding reaction method,.It crysta-]llizes in the triclinic.,space group P1 with ceIl parameters:a=O.90363(2)nm,b=1.25078(3)nm,c=1.41303(1)nm,穋m^(-3),Z=2,Mr=756.72,F(000)=760,Ⅲ)and the approxi-mately oriented octahedrally sixfold-coordinated Fe(Ⅲ)are linked by a cyano-bridge group to construct a dinuclear compound.The{[Gd(DMF)_(3)(DMSO)(H_(2)O)_(3)](Ⅲ)-Fe(Ⅲ)interaction is antiferromagnetic.CCDC:223430.
基金Supported by the Scientific Research Personnel of Northeast Agricultural University(518001)。
文摘Talin-1 head(hereinafter referred to as TH)is the head structure of talin protein,which contains a four-point-one-protein/ezrin/radixin/moesin(FERM)domain.Its F1 domain contains an unstructured loop of 30 amino acids(139-168),which does not interact with other domains.Because TH doesn’t get the crystal structure and whether the unstructured loop has obvious influence on the TH secondary structure,therefore,the truncated talin-1 headΔ139-168(hereinafter referred to as THΔ)was constructed and its structure and the impact of stability after truncation were analyzed.Molecular biology and structural biology methods were used to construct prokaryotic expression vectors of TH and THΔ,explore and optimize the expression conditions of recombinants,and they were purified by affinity chromatography and FPLC gel filtration chromatography.Finally,a large number of stable,high-purity protein samples were prepared successfully.The physicochemical properties and structural stability of the proteins were investigated by dynamic light scattering and circular dichroism.The results showed that the THΔsecondary structure of the truncated body did not change significantly,the structural stability was enhanced and the resistance to guanidine hydrochloride and high temperature was stronger.
