螺旋

The mechanics model of a ball screw was developed considering the factor of lead angle,and the main curvature of the helical surface was deduced using differential geometry method,and the effect of lead angle on the elastic deformation was analyzed.

考虑螺旋升角的因素，建立了滚珠丝杠副的受力模型，应用微分几何理论推导了螺旋面的主曲率，并进一步分析了螺旋升角对滚珠丝杠副弹性变形的影响。

The max stress and the max radial displacement of conveyor is also proportional to the square of rotational speed. With the decrease of the blade thickness, both the stress and axial displacement of conveyor increase rapidly. The stress and radial displacement will increase with the increment of half cone angle and lead.

螺旋输送器的最大应力强度和最大径向位移均与转速近似地成二次方关系；减小叶片壁厚，沉渣对螺旋叶片作用的正压力所引起的叶片的最大轴向位移增长较快；正常工况下，螺旋输送器的最大应力强度和最大径向位移都随着半锥角和导程的增加而增大。

For example, the growth initial condition selects the conformation of binormal zinc oxide helix, though the normal configuration is also stable only from the aspect of energy.

例如，我们发现如果初始生长条件选择了binormal型的氧化锌纳米螺旋带，尽管从能量的角度来说，normal型的氧化锌纳米螺旋带也可以稳定存在的，那么最后生长的为binormal型的氧化锌纳米螺旋带。

Effects of helix structure disorder about the hydrogen bond length and helix angle on charge transport of Poly-Polyhave been studied. The results indicate that the hydrogen bond length disorder has a significant effect on charge transport,while the case is contrary in the situation of helix angle disorder.

在双螺旋结构无序中研究了氢键键长无序和螺旋角无序对Poly-Poly电荷输运的影响，结果表明：氢键键长无序对其电荷输运有重要的影响，而螺旋角无序对其电荷输运影响不大。

The study leads to the conclusion that the circular comb slow wave structure has an impedance over 1 Ω at its fundamental mode within a relatively wide band and may interact with the beam effectively.

该结构内孔径为波长的1/4~1/3，是同一频段螺旋线慢波结构的5倍左右，能容纳比螺旋线大25倍的电流，能够承受比螺旋线大25倍的平均功率。

Another new spatial 3-RPS parallel pyramid manipulator mechanism is studied. The principal screws of this mechanism under three different configurations are identified by means of the conic section and the quadric degenerating theory, respectively. The planar conics representing the relations between the pitches of the output twists and the three linear inputs are described, and the three-dimensional distribution of the axes of all the twists with the same pitch is illustrated under each of the configurations.

研究了另一种新的空间三自由度3-RPS并联角台机构，分别用二次曲线和二次曲面分解法识别该机构在三种位形下的主螺旋，绘制了其在每种位形下的输出运动螺旋的节距与输入之间的平面图以及具有相同节距的所有运动螺旋轴线在每种位形下的空间分布的立体图。

This technique uses a spiral phase plate with a small central aperture placed on the Fourier plane of so imaging system. If the spiral phase filter is rotated by a certain angle around its central axis, a phase shift between the zero-order spatial frequency component and the remaining of the object is produced, and the magnitude of this phase shift is proportional to the rotation angle. Using this property, we can record a sequence of intensity distribution of the output beams corresponding to different rotation angles, and then digitally reconstruct the objects by using a phase-shifting algorithm. Both the theoretical analysis and simulation experiment results demonstrate the feasibility of this approach.

在成像系统的频谱面上放置中心带有一通光孔径的螺旋相位板，在输出面上记录输入物体经螺旋相位滤波后的输出像；将螺旋相位滤波器绕轴旋转一定角度，通过中心光孔的零频成份与其他高频成份间会产生与旋转角度成正比的相移；利用这一特点，通过记录多幅对应不同旋转角度的输出光场强度分布图，然后再用一定的相移算法实现被记录物体相位分布的数字再现。

This technique uses a spiral phase plate with a small central aperture placed on the Fourier plane of an imaging system. If the spiral phase filter is rotated by a certain angle around its central axis,a phase shift between the zero-order spatial frequency component and the remaining of the object is produced,and the magnitude of this phase Shift is proportional to the rotation angle. Using this property,we can record a sequence of intensity distribution of the output beams corresponding to different rotation angles,and then digitally reconstruct the objects by using a phase-shifting algorithm. Both the theoretical analysis and simulation experiment results demonstrate the feasibility of this approach.

在成像系统的频谱面上放置中心带有一通光孔径的螺旋相位板，在输出面上记录输入物体经螺旋相位滤波后的输出像；将螺旋相位滤波器绕轴旋转一定角度，通过中心光孔的零频成份与其他高频成份间会产生与旋转角度成正比的相移；利用这一特点，通过记录多幅对应不同旋转角度的输出光场强度分布图，然后再用一定的相移算法实现被记录物体相位分布的数字再现。

Bamboo mosaic virus encodes a 155-kDa replicase that the middle region contains a helicase-like domain according to the existence of several conserved featured motifs of helicase. Previous studies showed that the helicase-like domain exhibits both ATPase and RNA 5'-triphosphotase activities, and Mg2+ is essential for both activities. Mutagenesis of conserved motifs showed these amino acids play important roles for enzymatic activities. These results suggested that the properties of this denatured and renatured protein are coincident with other SF1 helicases.

从胺基酸序列分析显示，竹嵌纹病毒复制酵素中间区域的类解螺旋酵素具有解螺旋酵素的保留性胺基酸区域，经实验显示此蛋白具有ATPase和RNA 5'-triphosphatase活性，而且是依赖镁离子进行反应的，其中保留性胺基酸的突变会破坏其催化能力，说明这在大肠杆菌表达的蛋白质经过变性及重新摺叠的过程，具有和其他SF 1解螺旋酵素相似的特性。

Based on this property, by solving a series ODEs we construct a two-parametric family of helicoidal surfaces under cubic screw motion with prescribed mean curvature or Gauss curvature and solve an open problem left by Beneki.

基于这一点，当螺旋面的平均曲率或Gauss曲率为给定光滑函数时，本文选取伪正交标架，使得两类螺旋面的平均曲率和Gauss曲率的表达式相对简化，通过求解一系列的非线性常微分方程，即可确定一族生成曲线，从而最终确定平均血率或Gauss曲率为给定光滑函数的双参数族螺旋面，并在这一过程中解决了Beneki等人留下的一个公开问题。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失