In order to obtain high-quality spherical RDX crystal particles,the RDX crystals were suspended in a mixed solvent of cyclohexanone and cyclohexane,subsequently a solvent etching study was carried out under the action...In order to obtain high-quality spherical RDX crystal particles,the RDX crystals were suspended in a mixed solvent of cyclohexanone and cyclohexane,subsequently a solvent etching study was carried out under the action of vibration/acoustic flow coupled flow field,which generated by resonance acoustic mixing.The effects of solvent ratio,temperature,acceleration and experiment time on morphology as well as particle size of RDX crystals were studied.Not only were the morphology,particle size distribution and crystal form of RDX crystals determined,but also the thermal decomposition performance and mechanical sensitivity of spherical RDX were examined and discussed.Results indicated that under the process of solvent/non-solvent volume ratio at 1:2,temperature of 40℃,acceleration of 40 g and experiment time of 4 h,α-type RDX crystal with sphericity of 0.92 can be obtained.Furthermore,the median particle size(D_(50))of spherical RDX crystals is 215.8 μm with a unimodal particle size distribution(size span 1.34).For one thing,the thermal decomposition peak temperature of spherical RDX is about 2.5℃ higher than that of raw RDX,and apparent activation energy reaches 444.68 kJ/mol.For another thing,impact sensitivity and friction sensitivity of spherical RDX are 18.18% and 33.33% lower than that of raw RDX,respectively.It demonstrates that safety of spherical RDX under thermal,impact and friction stimuli has been improved.展开更多
考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水...考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。展开更多
Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the pres...Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the presence of catalyst promotor system,aiming at producing medium grade IS.Another is mixed solvent extraction process with a small amount of additive for the production of higher grade IS.In comparison with the old high temperature polymerization and single solvent (carbon disulfide) extraction processes respectively,these two new processes are lower in first cost and operation/maintainance cost,less energy consumption and safe in operation.展开更多
文摘In order to obtain high-quality spherical RDX crystal particles,the RDX crystals were suspended in a mixed solvent of cyclohexanone and cyclohexane,subsequently a solvent etching study was carried out under the action of vibration/acoustic flow coupled flow field,which generated by resonance acoustic mixing.The effects of solvent ratio,temperature,acceleration and experiment time on morphology as well as particle size of RDX crystals were studied.Not only were the morphology,particle size distribution and crystal form of RDX crystals determined,but also the thermal decomposition performance and mechanical sensitivity of spherical RDX were examined and discussed.Results indicated that under the process of solvent/non-solvent volume ratio at 1:2,temperature of 40℃,acceleration of 40 g and experiment time of 4 h,α-type RDX crystal with sphericity of 0.92 can be obtained.Furthermore,the median particle size(D_(50))of spherical RDX crystals is 215.8 μm with a unimodal particle size distribution(size span 1.34).For one thing,the thermal decomposition peak temperature of spherical RDX is about 2.5℃ higher than that of raw RDX,and apparent activation energy reaches 444.68 kJ/mol.For another thing,impact sensitivity and friction sensitivity of spherical RDX are 18.18% and 33.33% lower than that of raw RDX,respectively.It demonstrates that safety of spherical RDX under thermal,impact and friction stimuli has been improved.
文摘考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。
文摘Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the presence of catalyst promotor system,aiming at producing medium grade IS.Another is mixed solvent extraction process with a small amount of additive for the production of higher grade IS.In comparison with the old high temperature polymerization and single solvent (carbon disulfide) extraction processes respectively,these two new processes are lower in first cost and operation/maintainance cost,less energy consumption and safe in operation.
