硬盘包装在圆上的几何挫折
Jessica H Sun1, Abigail Plummer2, Grace H Zhang3
1Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Physical review. E
|December 20, 2023
概括
圆上的晶体生长在几何上受到封闭的挫折,形成和无序的包装. 这种挫折是一个有限大小的效应,取决于周长,影响单晶形成.
科学领域:
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 计算物理 计算物理
背景情况:
- 在曲表面的晶体生长面临着独特的挑战.
- 形表面的闭合约束可能导致几何挫折.
研究的目的:
- 调查几何挫折如何影响圆上的单晶生长.
- 分析角和种子方向在晶体形成中的作用.
- 了解导致无序颗粒包装的因素.
主要方法:
- 使用磁盘包装算法来模拟晶体生长.
- 不同的晶体种子方向和角参数.
- 开发了一种在晶体接处粒子附着的模型.
主要成果:
- 晶体通常在圆上形成轴接,但在相称的角度除外.
- 在圆尖附近出现了无序的粒子包装.
- 疾病的发作是一个有限大小的效应,取决于周长,而不是种子的方向或形角.
- 缺陷密度随着圆和圆柱体周长的减少而呈指数级增加.
结论:
- 由于几何限制,单晶生长可能会在小角度体上受到挫折.
- 周长是形和圆柱形表面晶体缺陷形成的关键因素.
- 这些发现提供了对生物和物质形晶体结构的洞察.
相关概念视频
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
270
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
270
Stress Concentrations in Circular Shafts
178
Consider the elastic torsion formula, which applies to a circular shaft with a consistent cross-section. This formula assumes that the shaft's ends are loaded with rigid plates firmly attached. However, in many cases, torques are applied to the shaft through mechanisms like flange couplings or gears, which are connected by keys inserted into keyways. This application method modifies the stress distribution near the point of torque application, causing it to deviate from the distributions...
178
General Case of Eccentric Axial Loading
186
Unsymmetrical bending occurs when the bending moment applied to a structural member does not align with its principal axis. This misalignment leads to complex stress distributions and deflection patterns that differ from symmetrical bending, which are essential for designing structures to withstand different loading conditions.
Consider a member subjected to equal and opposite forces that are applied along a line that does not coincide with the member's neutral axis. In unsymmetrical...
Consider a member subjected to equal and opposite forces that are applied along a line that does not coincide with the member's neutral axis. In unsymmetrical...
186
Eccentric Axial Loading in a Plane of Symmetry
199
Eccentric axial loading occurs when an axial load is applied away from the centroidal axis of a structural member. This scenario is common in engineering, where structural elements may not be directly aligned due to various design or functional requirements.
199
Gauss's Law: Cylindrical Symmetry
7.6K
A charge distribution has cylindrical symmetry if the charge density depends only upon the distance from the axis of the cylinder and does not vary along the axis or with the direction about the axis. In other words, if a system varies if it is rotated around the axis or shifted along the axis, it does not have cylindrical symmetry. In real systems, we do not have infinite cylinders; however, if the cylindrical object is considerably longer than the radius from it that we are interested in,...
7.6K
Gauss's Law: Planar Symmetry
8.0K
A planar symmetry of charge density is obtained when charges are uniformly spread over a large flat surface. In planar symmetry, all points in a plane parallel to the plane of charge are identical with respect to the charges. Suppose the plane of the charge distribution is the xy-plane, and the electric field at a space point P with coordinates (x, y, z) is to be determined. Since the charge density is the same at all (x, y) - coordinates in the z = 0 plane, by symmetry, the electric field at P...
8.0K


