Improving the application of nanomaterials has always been a research hotspot in the field of energetic materials(EMs)due to their obvious catalytic effect on the EMs,especially the uniformly dispersed nanomaterials.H...Improving the application of nanomaterials has always been a research hotspot in the field of energetic materials(EMs)due to their obvious catalytic effect on the EMs,especially the uniformly dispersed nanomaterials.However,few studies have reported the dispersion of nanomaterials.In this study,the dispersity and mixing uniformity of nano-CuCr_(2)O_(4)was evaluated based on the difference of solid UV light absorption between the nano-catalytic materials and EMs.The nano-CuCr_(2)O_(4)/ultrafine AP composites with different dispersity of nano-CuCr_(2)O_(4)were prepared by manual grinding and mechanical grinding with different grinding strength and griding time.And then,the absorbance of different samples at 212 nm was obtained by solid UV testing due to the high repeatability of the absorbance at 210-214 nm for three parallel experiments,and the dispersity of different samples was calculated through the established difference equation.Furthermore,the samples were characterized by XRD,IR,SEM,EDS,DSC and TG-MS,which confirmed that different mixing methods did not change the structure of the samples(XRD and IR),and the mixing uniformity improved with the increase of grinding strength and grinding time(SEM and EDS).The scientificity and feasibility of the difference equation were further verified by DSC.The dispersity of nano-CuCr_(2)O_(4)exhibits a positive intrinsic relationship with its catalytic performance,and the uniformly dispersed nano-CuCr_(2)O_(4)significantly reduces the thermal decomposition temperature of ultrafine AP from 367.7 to 338.8℃.The TG-MS patterns show that the dispersed nano-CuCr_(2)O_(4)advanced the thermal decomposition process of ultrafine AP by about 700 s,especially in the high temperature decomposition stage,and the more concentrated energy release characteristic is beneficial to further enhance the energy performance of AP-based propellants.The above conclusions show that the evaluation method of dispersity based on solid UV curves could provide new ideas for the dispersity characterization of nano-catalytic materials in EMs,which is expected to be widely used in the field of EMs.展开更多
文摘采用可见/近红外漫反射光谱技术对苹果可溶性固形物含量(Soluble solids content,SSC)检测时,光谱采集探头到苹果表面的距离变化是随机和不可控的,造成检测精度降低。并且采用特征波长筛选算法优化预测模型时,忽略了被舍弃光谱数据中所包含的与成分含量相关信息,造成光谱信息丢失。针对以上问题,通过探究检测距离对漫反射光谱的影响规律,提出一种距离校正方法(Distance correction,DC),并采用数据融合方法将特征波长和非特征波长数据中的有效信息相结合,以提高苹果SSC预测模型的预测性能。为了验证所提出方法的有效性,分别采用多元散射校正(Multiple scattering correction,MSC)、标准正态变换(Standard normal variate transform,SNV)和DC算法对苹果光谱预处理后,建立苹果SSC的偏最小二乘回归(Partial least squares regression,PLSR)模型。结果表明,DC能更加有效提升PLSR模型的预测性能。为了减少模型数据量、消除光谱中共线性和无效信息,在DC预处理光谱的基础上,采用竞争性自适应加权采样算法(Competitive adaptive reweighted sampling,CARS)、自举软收缩(Bootstrapping soft shrinkage,BOSS)和区间变量迭代空间收缩法(Interval variable iterative space shrinkage approach,iVISSA)对光谱数据进行特征波长筛选。建模结果表明,DC-CARS-PLSR模型具有较好预测结果,并且大幅减少了光谱数据量。为了充分利用特征波长和非特征波长数据中与苹果SSC相关的信息,将特征和非特征波长PLSR模型的潜变量得分相融合,建立融合PLSR预测模型。结果表明,所提出的数据融合方法能够进一步提高模型预测性能。其中CARS算法的特征波长和非特征波长数据融合建模结果具有最佳预测性能,校正集相关系数R_(c)、校正集均方根误差(Root mean square error of calibration,RMSEC)、预测集相关系数R_(p)、预测集均方根误差(Root mean square error of prediction,RMSEP)和相对分析误差(Relative percentage difference,RPD)分别为0.981、0.297%、0.957、0.469%和3.424。
基金the National Natural Science Foundation of China(Project Nos.21805139,21905023,12102194,22005144 and 22005145)the Joint Funds of the National Natural Science Foundation of China(Grant No.U2141202)+2 种基金Natural Science Foundation of Jiangsu Province(Grant No.BK20200471)the Fundamental Research Funds for the Central Universities(Grant Nos.30920041106,30921011203)Young Elite Scientists Sponsorship Program by CAST(Program,2021QNRC001).
文摘Improving the application of nanomaterials has always been a research hotspot in the field of energetic materials(EMs)due to their obvious catalytic effect on the EMs,especially the uniformly dispersed nanomaterials.However,few studies have reported the dispersion of nanomaterials.In this study,the dispersity and mixing uniformity of nano-CuCr_(2)O_(4)was evaluated based on the difference of solid UV light absorption between the nano-catalytic materials and EMs.The nano-CuCr_(2)O_(4)/ultrafine AP composites with different dispersity of nano-CuCr_(2)O_(4)were prepared by manual grinding and mechanical grinding with different grinding strength and griding time.And then,the absorbance of different samples at 212 nm was obtained by solid UV testing due to the high repeatability of the absorbance at 210-214 nm for three parallel experiments,and the dispersity of different samples was calculated through the established difference equation.Furthermore,the samples were characterized by XRD,IR,SEM,EDS,DSC and TG-MS,which confirmed that different mixing methods did not change the structure of the samples(XRD and IR),and the mixing uniformity improved with the increase of grinding strength and grinding time(SEM and EDS).The scientificity and feasibility of the difference equation were further verified by DSC.The dispersity of nano-CuCr_(2)O_(4)exhibits a positive intrinsic relationship with its catalytic performance,and the uniformly dispersed nano-CuCr_(2)O_(4)significantly reduces the thermal decomposition temperature of ultrafine AP from 367.7 to 338.8℃.The TG-MS patterns show that the dispersed nano-CuCr_(2)O_(4)advanced the thermal decomposition process of ultrafine AP by about 700 s,especially in the high temperature decomposition stage,and the more concentrated energy release characteristic is beneficial to further enhance the energy performance of AP-based propellants.The above conclusions show that the evaluation method of dispersity based on solid UV curves could provide new ideas for the dispersity characterization of nano-catalytic materials in EMs,which is expected to be widely used in the field of EMs.