共查询到20条相似文献,搜索用时 109 毫秒
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一维高分子链中点缺陷引起的局域模 总被引:2,自引:1,他引:1
将聚苯胺等一类聚合物简化成一维复式线性链,讨论了这一类聚合物仅含一个点缺陷时的振动模.考虑到点缺陷附近弹性恢复力常数的变化,预期了局域模的出现,说明了模的局域化程度,包括模的频移及振动本征矢的分布情况与质量缺陷程度、力常数改变程度的关系. 相似文献
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在磁流体模拟代码BOUT++剥离气球模三场模块框架下研究了等离子体形变参数(拉长比和三角形变)对边界局域模的影响。研究表明,在线性阶段,拉长比主要作用于剥离气球模中气球模成分,抑制了环向模数较高的气球模不稳定性;而三角形变则对剥离气球模中剥离模成分和气球模成分均有抑制作用。在非线性阶段,拉长比导致边界E×B剪切率增加,迫使压强扰动的正值部分向等离子体芯部发展,导致边界局域模的能量损失增加;三角形变则导致边界E×B剪切率降低,使得压强扰动可以向等离子体边缘发展,台基向等离子体芯部的崩塌减弱,从而对边界局域模起到缓解作用。 相似文献
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Solitons and intrinsic localized modes in a one-dimensional antiferromagnetic chain 总被引:3,自引:0,他引:3 下载免费PDF全文
By use of the Hartree approximation and the method of multiple scales, we
investigate quantum solitons and intrinsic localized modes in a
one-dimensional antiferromagnetic chain. It is shown that there exist
solitons of two different quantum frequency bands: i.e., magnetic optical
solitons and acoustic solitons. At the boundary of the Brillouin zone, these
solitons become quantum intrinsic localized modes: their quantum
eigenfrequencies are below the bottom of the harmonic optical frequency band
and above the top of the harmonic acoustic frequency band. 相似文献
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在一维均匀铁磁链中磁振动的内禀局域模 总被引:2,自引:2,他引:0
利用多标度方法和准离散近似,我们考察了在一维均匀铁磁链中磁振动的内禀局域模; 结果表明磁振动的内禀局域模在许多方面都与晶格振动的内禀局域模相类似;它们是近邻自旋之间非线性相互作用的结果.这种内禀局域模的存在并没有破坏系统的平移对称性,它们能在任何晶格位被激发.它们的量子本征频率在简谐磁振动频带的上方. 相似文献
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Takahiro Shimada Daisuke Shirasaki Yusuke Doi Takayuki Kitamura 《Physica D: Nonlinear Phenomena》2010,239(8):407-413
Excitation of intrinsic localized modes (ILMs) in carbon nanotubes (CNTs) with different chiral structures was investigated by molecular dynamics simulations. For CNTs with a chiral angle less than or equal to 30°, energy concentration that continued for more than 200 fs was found in a localized area, where a pair of neighboring atoms strongly oscillated with a higher vibrational frequency than the upper bound of phonon bands. This evidently indicates excitation of the ILM. On the other hand, the ILM was not excited in CNTs with a chiral angle greater than or equal to 41°. Analyzing the nonlinearity of the interaction between excited atoms in the ILM vibration mode, we elucidated that nonlinearity predominates the selective ILM excitation. Furthermore, stronger nonlinearity excites ILMs with both higher frequency and longer lifetime. 相似文献
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We explore the nature of intrinsic localized modes (ILMs) in a curved Fermi-Pasta-Ulam (FPU) chain and the effects of geometry
and second-neighbor interaction on the localization and movability properties of such modes. We determine analytically the
structure of the localized modes induced by an isotopic light-mass impurity in this chain. We further demonstrate that a nonlinear
impurity mode may be treated as a bound state of an ILM with the impurity.
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具有格点各向异性的一维铁磁链中的量子孤子和内禀局域模(英文) 总被引:1,自引:0,他引:1
基于Hartree-Fock方法和多标度方法,我们考察了具有格点各向异性的一维铁磁链中的量子孤子和内禀局域模,量子磁振子的波函数由量子包络孤子来描述.在布里渊区边界,量子包络孤子变成了量子内禀局域模,它的量子本征频率在简谐波带的顶部上方,量子磁振子主要集中在中心位置j=j0的附近. 相似文献
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Bright and dark small amplitude nonlinear localized modes in a quantum one-dimensional Klein--Gordon chain 总被引:1,自引:0,他引:1 下载免费PDF全文
By means of the Glauber's coherent state method combined with multiple-scale method, this paper investigates the localized modes in a quantum one-dimensional Klein-Gordon chain and finds that the equation of motion of annihilation operator is reduced to the nonlinear Schroedinger equation. Interestingly, the model can support both bright and dark small amplitude travelling and non-travelling nonlinear localized modes in different parameter spaces. 相似文献
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高约束模式(H模)下自发产生的边缘局域模(ELM),虽然利于控制等离子体密度和排出杂质粒子从而实现H模放电的稳态运行,但是ELM爆发携带的大量粒子和能量会对装置的第一壁材料造成很大的损坏,所以在下一代聚变装置上使用之前很多装置已经开始了对ELM的研究.在HL-2A装置上观察到了不同的ELM,扰动幅度小的ELM引起的等离子体储能损失小于3%,ELM之间的时间间隔约为3 ms,表现出Ⅲ型ELM的特征;扰动幅度较大的ELM的爆发对等离子体电流、等离子体密度及储能都有很明显的扰动,对等离子体储能的扰动大于10%,ELM爆发的频率随通过等离子体磁分界面的净加热功率的增加而增加,表现出明显的Ⅰ型ELM的特征.ELM先兆有不对称性,在弱场侧磁探针信号能观测到,但强场侧却观测不到;ELM先兆的频率约为45 kHz,观测到的最长的先兆先于ELM前约10ms出现. 相似文献