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Evaluating accuracy of Hessian-based predictor-corrector integrators
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作者 lu shao-fei WU Heng LIU Xu-chong 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第7期1696-1702,共7页
Direct dynamics simulations are a useful and general approach for studying the atomistic properties of complex chemical systems because they do not require fitting an analytic potential energy function.Hessian-based p... Direct dynamics simulations are a useful and general approach for studying the atomistic properties of complex chemical systems because they do not require fitting an analytic potential energy function.Hessian-based predictor-corrector integrators are a widely used approach for calculating the trajectories of moving atoms in direct dynamics simulations.We employ a monodromy matrix to propose a tool for evaluating the accuracy of integrators in the trajectory calculation.We choose a general velocity Verlet as a different object.We also simulate molecular with hydrogen(CO_2) and molecular with hydrogen(H_2O) motions.Comparing the eigenvalues of monodromy matrix,many simulations show that Hessian-based predictor-corrector integrators perform well for Hessian updates and non-Hessian updates.Hessian-based predictor-corrector integrator with Hessian update has a strong performance in the H_2O simulations.Hessian-based predictor-corrector integrator with Hessian update has a strong performance when the integrating step of the velocity Verlet approach is tripled for the predicting step.In the CO_2 simulations,a strong performance occurs when the integrating step is a multiple of five. 展开更多
关键词 MONODROMY matrix eigenvalue Hessian-based PREDICTOR-CORRECTOR velocity Verlet
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裂解C_(9)组分制备高纯度双环戊二烯技术研究
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作者 张怀敏 张启 +1 位作者 鲁少飞 武建庆 《当代化工》 CAS 2023年第4期838-841,共4页
裂解C_(9)组分中含有大量的双环戊二烯馏分,为了提高回收双环戊二烯的纯度,采用常压蒸馏的方式从裂解C9组分中回收双环戊二烯,然后通过气相解聚的方式将其裂解成环戊二烯,最后再通过聚合的方式制备高纯度的双环戊二烯。不同阶段工艺参... 裂解C_(9)组分中含有大量的双环戊二烯馏分,为了提高回收双环戊二烯的纯度,采用常压蒸馏的方式从裂解C9组分中回收双环戊二烯,然后通过气相解聚的方式将其裂解成环戊二烯,最后再通过聚合的方式制备高纯度的双环戊二烯。不同阶段工艺参数优化实验结果表明:当精馏塔顶温度为106℃、回流比为2时,常压蒸馏后回收双环戊二烯的效果最好,收率可以达到85.6%;当氮气与双环戊二烯的摩尔比为2、反应时间为8 s、一段反应温度为260℃、二段反应温度为280℃时,气相解聚效果最好,双环戊二烯的解聚率可以达到99.9%,环戊二烯的收率可以达到98.8%;当聚合反应时间为10h、聚合反应温度为80℃时,采用聚合法制备的双环戊二烯纯度可以达到99.1%,达到了高纯度产品的要求。 展开更多
关键词 裂解C9组分 双环戊二烯 高纯度 气相解聚 聚合
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