In the case where the knowledge of goal states is not known, the controllers are constructed to stabilize unstable steady states for a coupled dynamos system. A delayed feedback control technique is used to suppress c...In the case where the knowledge of goal states is not known, the controllers are constructed to stabilize unstable steady states for a coupled dynamos system. A delayed feedback control technique is used to suppress chaos to unstable focuses and unstable periodic orbits. To overcome the topological limitation that the saddle-type steady state cannot be stabilized, an adaptive control based on LaSalle＇s invariance principle is used to control chaos to unstable equilibrium （i.e. saddle point, focus, node, etc.）. The control technique does not require any computer analysis of the system dynamics, and it operates without needing to know any explicit knowledge of the desired steady-state position.展开更多
Recently torsion fields were introduced in CP-violating cosmic axion a2-dynamos [Garcia de Andrade, Mod Phys Lett A, (2011)] in order to obtain Lorentz violating bounds for torsion. Here instead, oscillating axion sol...Recently torsion fields were introduced in CP-violating cosmic axion a2-dynamos [Garcia de Andrade, Mod Phys Lett A, (2011)] in order to obtain Lorentz violating bounds for torsion. Here instead, oscillating axion solutions of the dynamo equation with torsion modes [Garcia de Andrade, Phys Lett B (2012)] are obtained taking into account dissipative torsion fields. Magnetic helicity torsion oscillatory contribution is also obtained. Note that the torsion presence guarantees dynamo efficiency when axion dynamo length is much stronger than the torsion length. Primordial axion oscillations due to torsion yield a magnetic field of 109 G at Nucleosynthesis epoch. This is obtained due to a decay of BBN magnetic field of 1015 G induced by torsion. Since torsion is taken as 10–20 s–1, the dynamo efficiency is granted over torsion damping. Of course dynamo efficiency is better in the absence of torsion. In the particular case when the torsion is obtained from anomalies it is given by the gradient of axion scalar [Duncan et al., Nuclear Phys B 87, 215] that a simpler dynamo equation is obtained and dynamo mechanism seems to be efficient when the torsion helicity, is negative while magnetic field decays when the torsion is positive. In this case an extremely huge value for the magnetic field of 1015 Gauss is obtained. This is one order of magnitude greater than the primordial magnetic fields of the domain wall. Actually if one uses tDW ~ 10-4 s one obtains BDW ~ 1022 G which is a more stringent limit to the DW magnetic primordial field.展开更多
为优化水利工程信息数据采集、管理、处理过程繁杂、可视程度较低、时间相关性较弱等问题,该文结合头屯河水库实际工程,基于建筑信息模型(Building Information Modeling,BIM)技术实现该工程水文信息的可视化设计,利用Dynamo可视化编程...为优化水利工程信息数据采集、管理、处理过程繁杂、可视程度较低、时间相关性较弱等问题,该文结合头屯河水库实际工程,基于建筑信息模型(Building Information Modeling,BIM)技术实现该工程水文信息的可视化设计,利用Dynamo可视化编程插件开发一套嵌入在BIM模型内的新型工作接口,通过该接口可对水利工程信息实现模块化管理与更新。通过附有水文信息时间变量,创建具备4D时间参数的水文信息模型,实现水文模型在空间与时间上的有机统一,有助于管理人员更加科学、有效地预测来水趋势。展开更多
基金supported by the Doctoral Foundation of North China Electric Power University (Grant No. kH0433)the International Science and Technology Cooperation Program (Grant No. 2007DFA71250)
文摘In the case where the knowledge of goal states is not known, the controllers are constructed to stabilize unstable steady states for a coupled dynamos system. A delayed feedback control technique is used to suppress chaos to unstable focuses and unstable periodic orbits. To overcome the topological limitation that the saddle-type steady state cannot be stabilized, an adaptive control based on LaSalle＇s invariance principle is used to control chaos to unstable equilibrium （i.e. saddle point, focus, node, etc.）. The control technique does not require any computer analysis of the system dynamics, and it operates without needing to know any explicit knowledge of the desired steady-state position.
文摘Recently torsion fields were introduced in CP-violating cosmic axion a2-dynamos [Garcia de Andrade, Mod Phys Lett A, (2011)] in order to obtain Lorentz violating bounds for torsion. Here instead, oscillating axion solutions of the dynamo equation with torsion modes [Garcia de Andrade, Phys Lett B (2012)] are obtained taking into account dissipative torsion fields. Magnetic helicity torsion oscillatory contribution is also obtained. Note that the torsion presence guarantees dynamo efficiency when axion dynamo length is much stronger than the torsion length. Primordial axion oscillations due to torsion yield a magnetic field of 109 G at Nucleosynthesis epoch. This is obtained due to a decay of BBN magnetic field of 1015 G induced by torsion. Since torsion is taken as 10–20 s–1, the dynamo efficiency is granted over torsion damping. Of course dynamo efficiency is better in the absence of torsion. In the particular case when the torsion is obtained from anomalies it is given by the gradient of axion scalar [Duncan et al., Nuclear Phys B 87, 215] that a simpler dynamo equation is obtained and dynamo mechanism seems to be efficient when the torsion helicity, is negative while magnetic field decays when the torsion is positive. In this case an extremely huge value for the magnetic field of 1015 Gauss is obtained. This is one order of magnitude greater than the primordial magnetic fields of the domain wall. Actually if one uses tDW ~ 10-4 s one obtains BDW ~ 1022 G which is a more stringent limit to the DW magnetic primordial field.
文摘为优化水利工程信息数据采集、管理、处理过程繁杂、可视程度较低、时间相关性较弱等问题,该文结合头屯河水库实际工程,基于建筑信息模型(Building Information Modeling,BIM)技术实现该工程水文信息的可视化设计,利用Dynamo可视化编程插件开发一套嵌入在BIM模型内的新型工作接口,通过该接口可对水利工程信息实现模块化管理与更新。通过附有水文信息时间变量,创建具备4D时间参数的水文信息模型,实现水文模型在空间与时间上的有机统一,有助于管理人员更加科学、有效地预测来水趋势。
