Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesi...Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesized a sandwich structure of CL-20 and nanoporous carbon scaffolds film(NCS)and emphatically studied the thermal decomposition performance of the composite structure.Thermogravimetric analysis and differential scanning calorimetry were used to measure the thermal decomposition process of the composite structure.The kinetic parameters of thermal decomposition were calculated by the thermal dynamic analysis software AKTS.These results showed that the thermal decomposition performance of the sandwich structure of CL-20 and NCS was better than CL-20.Among the tested samples,NCS with a pore size of 15 nm had the best catalytic activity for the thermal decomposition of CL-20.Moreover,the thermal decomposition curve of the composite structure at the heating rate of 1 K/min was deconvoluted by mathematical method to study the thermal decomposition process.And a possible catalytic mechanism was proposed.The excellent thermal decomposition performance is due to the sandwich structure enhances the interface reaction of CL-20 and NCS.This work may promote the extensive use of CL-20 in the field of solid rocket propellant.展开更多
A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2...A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.展开更多
Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accident...Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.展开更多
With the development of digital information technologies,robust watermarking framework is taken into real consideration as a challenging issue in the area of image processing,due to the large applicabilities and its u...With the development of digital information technologies,robust watermarking framework is taken into real consideration as a challenging issue in the area of image processing,due to the large applicabilities and its utilities in a number of academic and real environments.There are a wide range of solutions to provide image watermarking frameworks,while each one of them is attempted to address an efficient and applicable idea.In reality,the traditional techniques do not have sufficient merit to realize an accurate application.Due to the fact that the main idea behind the approach is organized based on contourlet representation,the only state-of-the-art materials that are investigated along with an integration of the aforementioned contourlet representation in line with watermarking framework are concentrated to be able to propose the novel and skilled technique.In a word,the main process of the proposed robust watermarking framework is organized to deal with both new embedding and de-embedding processes in the area of contourlet transform to generate watermarked image and the corresponding extracted logo image with high accuracy.In fact,the motivation of the approach is that the suggested complexity can be of novelty,which consists of the contourlet representation,the embedding and the corresponding de-embedding modules and the performance monitoring including an analysis of the watermarked image as well as the extracted logo image.There is also a scrambling module that is working in association with levels-directions decomposition in contourlet embedding mechanism,while a decision maker system is designed to deal with the appropriate number of sub-bands to be embedded in the presence of a series of simulated attacks.The required performance is tangibly considered through an integration of the peak signal-to-noise ratio and the structural similarity indices that are related to watermarked image.And the bit error rate and the normal correlation are considered that are related to the extracted logo analysis,as well.Subsequently,the outcomes are fully analyzed to be competitive with respect to the potential techniques in the image colour models including hue or tint in terms of their shade,saturation or amount of gray and their brightness via value or luminance and also hue,saturation and intensity representations,as long as the performance of the whole of channels are concentrated to be presented.The performance monitoring outcomes indicate that the proposed framework is of significance to be verified.展开更多
针对特高压接入的输电网网架错综复杂、远景适应性差,甚至出现网架规划与开环分区决策相互独立导致资源浪费等问题,该文引入奇异值分解(singular value decomposition,SVD)和特征索引技术,提出了一种考虑电磁环网开环分区和500/220kV典...针对特高压接入的输电网网架错综复杂、远景适应性差,甚至出现网架规划与开环分区决策相互独立导致资源浪费等问题,该文引入奇异值分解(singular value decomposition,SVD)和特征索引技术,提出了一种考虑电磁环网开环分区和500/220kV典型供电结构的输电网多阶段规划方法。首先,提取典型供电结构的路径特征,制定了一种基于标签路径特征的典型供电结构索引策略;然后,构建了一种基于SVD的典型供电结构相似度指标,基于此,以全局典型供电结构相似程度最大为目标,建立了相似度识别规划模型;最后,提出了一种反馈调节机制及求解方法,统筹协调各阶段网架规划和开环分区之间的决策信息。与传统规划方法相比,该文方法不仅能够避免不同阶段开环分区决策导致的资源浪费,还可以减少复杂的规划评估指标计算,构建供电可靠性高、运行方式灵活、远景适应性强的网架结构。基于湖南某地区实际电网算例验证了该文方法的准确性和有效性。展开更多
基金supported by the National Natural Science Foundation of China(No:21975227)the Shanxi Province Graduate Student Innovation Project(No:2020SY403)。
文摘Improving the thermal decomposition performance of hexanitrohexaazaisowurtzitane(CL-20)by appropriate methods is helpful to promote the combustion performance of CL-20-based solid propellants.In this study,we synthesized a sandwich structure of CL-20 and nanoporous carbon scaffolds film(NCS)and emphatically studied the thermal decomposition performance of the composite structure.Thermogravimetric analysis and differential scanning calorimetry were used to measure the thermal decomposition process of the composite structure.The kinetic parameters of thermal decomposition were calculated by the thermal dynamic analysis software AKTS.These results showed that the thermal decomposition performance of the sandwich structure of CL-20 and NCS was better than CL-20.Among the tested samples,NCS with a pore size of 15 nm had the best catalytic activity for the thermal decomposition of CL-20.Moreover,the thermal decomposition curve of the composite structure at the heating rate of 1 K/min was deconvoluted by mathematical method to study the thermal decomposition process.And a possible catalytic mechanism was proposed.The excellent thermal decomposition performance is due to the sandwich structure enhances the interface reaction of CL-20 and NCS.This work may promote the extensive use of CL-20 in the field of solid rocket propellant.
基金Project(2012GK2025)supported by Science-Technology Plan Foundation of Hunan Province,ChinaProject(2013zzts039)supported by the Fundamental Research Funds for Central South University,China
文摘A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.
基金supported in part by the National Natural Science Foundation of China(No.22075146)。
文摘Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.
文摘With the development of digital information technologies,robust watermarking framework is taken into real consideration as a challenging issue in the area of image processing,due to the large applicabilities and its utilities in a number of academic and real environments.There are a wide range of solutions to provide image watermarking frameworks,while each one of them is attempted to address an efficient and applicable idea.In reality,the traditional techniques do not have sufficient merit to realize an accurate application.Due to the fact that the main idea behind the approach is organized based on contourlet representation,the only state-of-the-art materials that are investigated along with an integration of the aforementioned contourlet representation in line with watermarking framework are concentrated to be able to propose the novel and skilled technique.In a word,the main process of the proposed robust watermarking framework is organized to deal with both new embedding and de-embedding processes in the area of contourlet transform to generate watermarked image and the corresponding extracted logo image with high accuracy.In fact,the motivation of the approach is that the suggested complexity can be of novelty,which consists of the contourlet representation,the embedding and the corresponding de-embedding modules and the performance monitoring including an analysis of the watermarked image as well as the extracted logo image.There is also a scrambling module that is working in association with levels-directions decomposition in contourlet embedding mechanism,while a decision maker system is designed to deal with the appropriate number of sub-bands to be embedded in the presence of a series of simulated attacks.The required performance is tangibly considered through an integration of the peak signal-to-noise ratio and the structural similarity indices that are related to watermarked image.And the bit error rate and the normal correlation are considered that are related to the extracted logo analysis,as well.Subsequently,the outcomes are fully analyzed to be competitive with respect to the potential techniques in the image colour models including hue or tint in terms of their shade,saturation or amount of gray and their brightness via value or luminance and also hue,saturation and intensity representations,as long as the performance of the whole of channels are concentrated to be presented.The performance monitoring outcomes indicate that the proposed framework is of significance to be verified.
文摘针对特高压接入的输电网网架错综复杂、远景适应性差,甚至出现网架规划与开环分区决策相互独立导致资源浪费等问题,该文引入奇异值分解(singular value decomposition,SVD)和特征索引技术,提出了一种考虑电磁环网开环分区和500/220kV典型供电结构的输电网多阶段规划方法。首先,提取典型供电结构的路径特征,制定了一种基于标签路径特征的典型供电结构索引策略;然后,构建了一种基于SVD的典型供电结构相似度指标,基于此,以全局典型供电结构相似程度最大为目标,建立了相似度识别规划模型;最后,提出了一种反馈调节机制及求解方法,统筹协调各阶段网架规划和开环分区之间的决策信息。与传统规划方法相比,该文方法不仅能够避免不同阶段开环分区决策导致的资源浪费,还可以减少复杂的规划评估指标计算,构建供电可靠性高、运行方式灵活、远景适应性强的网架结构。基于湖南某地区实际电网算例验证了该文方法的准确性和有效性。
