Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studi...Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studied. Although the experimental results indicate some decomposition when the mixture of higher primary aliphatic alcohols is distillated by SPD, SPD is still an effective method to purify octacosanol. It is concluded that evaporation temperature affects greatly on the purity and recovery of octacosanol.展开更多
为解决复杂动态环境下全自主移动机器人路径规划存在的效率低、适应性差及多目标权衡难题,提出全自主移动机器人全局最优路径智能规划方法。利用图注意力网络与空间重构单元提取环境的全局最优路径特征,采用改进基于密度的带噪声应用空...为解决复杂动态环境下全自主移动机器人路径规划存在的效率低、适应性差及多目标权衡难题,提出全自主移动机器人全局最优路径智能规划方法。利用图注意力网络与空间重构单元提取环境的全局最优路径特征,采用改进基于密度的带噪声应用空间聚类(Density-Based Spatial Clustering of Applications with Noise,DBSCAN)算法实现静态/动态障碍物与通行区的精准划分,构建长短期记忆(Long Short-Term Memory,LSTM)运动预测模型与多传感器融合的障碍物轨迹预测模型。在改进蚁群算法框架下进行全局路径搜索,引入路径长度、时间、安全及能耗的复合权重。采用3次B样条曲线平滑优化路径,引入曲率约束以抑制龙格现象。实验显示,该方法在低负载时段平均路径偏差降低约33%,重规划次数减少约66%,动态避障成功率提高至98%;高负载时段平均路径偏差降低40%,重规划次数减少约52%,成功率达95%。展开更多
Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore ...Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore a new method for enzymatic synthesis of biodiesel with methyl methacrylate(MMA)as acyl acceptor.Meanwhile,a 1,3-position specific lipase Lipozyme RM IM was applied as biocatalyst,which enables simultaneous production of biodiesel(FAMEs)and methacrylate fatty acid glycerides(MFAGs)via specific sn-1,3 transesterification of MMA with triglyceride.Under the optimal reaction conditions:temperature of 50℃,molar ratio of 4:1 for MMA to triglyceride,enzyme dosage of 7.5%(mass),and an extra water addition of 0.5%(mass);triglyceride conversion rate of 97%,and FAMEs yield of 65%could be obtained.Simultaneously,the multistage short-path distillation and column chromatographic method were combined used for the separation of the mixed products.Finally,the purity of FAME,MFADG,DMFAG,and MMFAG were 98%,97.8%,95.3%,and 81.78%,respectively.In this new approach,MMA demonstrates lower toxicity to lipases,allowing for straightfo rward addition of all the substrates without complex addition process,and enhancing operational feasibility.Meanwhile,the by-products of MFAGs could be applied as monomers in varnishes and protective coatings,which increased the value of the products.Thus,this investigation providing an alternative way to produce biodiesel,and providing a new pathway for the sustainable development of biodiesel.展开更多
基金Supported by the National Natural Science Foundation of China(No. 20176037), and the Development Foundation from the Science & Technology Commission of Tianjin, China (No. 01310864).
文摘Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studied. Although the experimental results indicate some decomposition when the mixture of higher primary aliphatic alcohols is distillated by SPD, SPD is still an effective method to purify octacosanol. It is concluded that evaporation temperature affects greatly on the purity and recovery of octacosanol.
文摘为解决复杂动态环境下全自主移动机器人路径规划存在的效率低、适应性差及多目标权衡难题,提出全自主移动机器人全局最优路径智能规划方法。利用图注意力网络与空间重构单元提取环境的全局最优路径特征,采用改进基于密度的带噪声应用空间聚类(Density-Based Spatial Clustering of Applications with Noise,DBSCAN)算法实现静态/动态障碍物与通行区的精准划分,构建长短期记忆(Long Short-Term Memory,LSTM)运动预测模型与多传感器融合的障碍物轨迹预测模型。在改进蚁群算法框架下进行全局路径搜索,引入路径长度、时间、安全及能耗的复合权重。采用3次B样条曲线平滑优化路径,引入曲率约束以抑制龙格现象。实验显示,该方法在低负载时段平均路径偏差降低约33%,重规划次数减少约66%,动态避障成功率提高至98%;高负载时段平均路径偏差降低40%,重规划次数减少约52%,成功率达95%。
文摘Traditional biodiesel production primarily uses methanol as the acyl acceptor,but its toxicity to lipase increases process complexity and operational difficulty elevate manufacturing costs.This study aimed to explore a new method for enzymatic synthesis of biodiesel with methyl methacrylate(MMA)as acyl acceptor.Meanwhile,a 1,3-position specific lipase Lipozyme RM IM was applied as biocatalyst,which enables simultaneous production of biodiesel(FAMEs)and methacrylate fatty acid glycerides(MFAGs)via specific sn-1,3 transesterification of MMA with triglyceride.Under the optimal reaction conditions:temperature of 50℃,molar ratio of 4:1 for MMA to triglyceride,enzyme dosage of 7.5%(mass),and an extra water addition of 0.5%(mass);triglyceride conversion rate of 97%,and FAMEs yield of 65%could be obtained.Simultaneously,the multistage short-path distillation and column chromatographic method were combined used for the separation of the mixed products.Finally,the purity of FAME,MFADG,DMFAG,and MMFAG were 98%,97.8%,95.3%,and 81.78%,respectively.In this new approach,MMA demonstrates lower toxicity to lipases,allowing for straightfo rward addition of all the substrates without complex addition process,and enhancing operational feasibility.Meanwhile,the by-products of MFAGs could be applied as monomers in varnishes and protective coatings,which increased the value of the products.Thus,this investigation providing an alternative way to produce biodiesel,and providing a new pathway for the sustainable development of biodiesel.
