查询词典 spiral

1Niche construction can lead to stable coexistence of diverse genotypes in spatially structured population, which supports a stable polymorphism even without heterozygote superiority.(2)With habitat deterioration, niche construction accelerates the formation of steady polymorphism and hence impedes the harmful influences of environment on the population, which might embody a life-history strategy of organism under the unfavorable environment.(3)Niche construction results in the coexistence with alternative polymorphism through genotype-environment feedback and limited gene flow.(4)The niche-constructing organism is an active force to alter its environment and hence the direction of natural selection in order to better survival.(5)Spatial dynamics and distribution pattern of metapopulation are profoundly influenced by time-lagged niche construction.(6)Metapopulation size can reach a fixed level in the recency effect and equal weighting of time lag but is statistical stability in primacy effect, which implies the primacy effect is most remarkable.(7)The increment in the relative weightingof each generation\' niche construction and the length of time lag are significant factors for system destabilization.(8)Moderate capacity of positive niche construction benefits the metapopulation persistence.(9)The narrowing of niche breadth can decrease the metapopulation size and thereby increase the extinction risk.(10)The coupled function of time lag and niche construction make the system oscillation and generate the spiral wave, spiral-broken and circular wave in heterogeneous habitat.The spatial distributions of metapopulation and resource content are complementary due to a phase lag of their both frequencies.(12)Metapopulation persistence with niche construction depends not only on the balance between colonization and extinction, but also on the balance between the ability of niche construction and natural dissipation of habitat.(13)Metapopula-tion can survive under certain condition when the percent of suitable patches in habitat is lower than the ration of extinction to colonization.(14)Two thresholds exist in the process of transition of habitat quality dynamics from unsuitable to suitable, which include the intensity of niche construction and the initial condition of system.(15)Metapopulation size is positive correlated with the ability of positive niche construction, which means that organism or population who has strongly positive influences on their environment plays an important role to maintain the available habitat.

通过上述几个方面的研究，主要得出以下15条结论：(1)生态位构建可使空间结构种群，甚至是在没有杂合子优势的条件下，形成多种可能的稳定基因型分布模式；(2)随着环境的破坏与恶化，种群的生态位构建作用加速其较早形成稳定多态以阻碍环境对种群的不利影响，解释了有机体在不利环境下的一种生活史对策；(3)生态位构建作用通过基因型—环境反馈机制及有限的基因交流导致基因型多态的稳定共存；(4)有机体的生态位构建作用是一种积极的动力改变环境进而改变其自然选择的方向；(5)生态位构建的时滞作用对集合种群动态和空间分布产生深刻影响；(6)集合种群大小在时滞的崭新效应和等权重效应下达到一固定值，而在首位效应下达到统计稳定，表明首位效应的影响最显著；(7)首位效应下生态位构建相对权重的增量和时滞的长度是影响系统不稳定性动态的关键因素；(8)适中的生态位构建强度有利于集合种群的续存；(9)生态位宽度变窄会减少集合种群的数量从而增加其灭绝风险；(10)时滞和生态位构建的双重作用使系统产生周期振荡，并在异质性环境中产生稳定的螺旋波，破碎的螺旋波和环形波三种分布模式；(11)集合种群与资源含量的空间分布因为相滞而互补；(12)具有生态位构建的集合种群续存不仅取决于侵占率与灭绝率之间的平衡，而且依赖于生态位构建能力同其生境的自然消耗速率之间的妥协；(13)当生境中适合侵占的斑块比例小于其侵占率与灭绝率之比时，生态位构建作用促使集合种群在一定条件下续存：(14)生境斑块的状态从不适合到适合转变过程中存在生态位构建强度和系统初始条件这两个阈值；(15)集合种群的大小同正生态位构建能力正相关，意味着对环境具有较强正作用的有机体对维持有效生境起积极作用。

Secondly, it analyses the line type between stator and rotor of PDM, gets its derivation bone line equation that satisfies the motor conjugate line type of theoretical sealing and the equation of curved surface, and determines its basic processing method and technology according to the line type characteristic of the spiral curve through analyzing some kinds of typical spiral curve processing methods.

其次，对螺杆钻具定子与转子进行线型分析，推导出其满足理论密封性的马达共轭线型的骨线方程和曲面方程，根据螺杆钻具定子内孔螺旋曲线的线型特点，在分析了几种典型的加工螺旋曲线加工方法的基础上，确定了其基本的加工方法和工艺。

For satisfying to process to keep a mother line, arc mother line, whole convex degree, half convex degree, ligarithmic curve cone, cylinder roll son of demand, ability according to design whet to submit have already corresponded form noodles of spiral lead a round, spiral lead Gun, double the song lead Gun, three convex Fengs to lead Gun, and arc plank and other similar of work piece etc..

为满足加工直母线、圆弧母线、全凸度、半凸度、对数曲线圆锥、圆柱滚子的需要，能根据设计磨出具有相应形面的螺旋导轮、螺旋导辊、双曲导辊、三凸峰导辊、以及圆弧支板以及其他类似的工件等。

Two new Cornu spiral s are obtained by reducing and rotating the known Cornu spiral ,and the relative intensity distribution on the diffraction screen is analysed too.

运用缩小和旋转Cornu卷线的方法，作出了两条新的Cornu卷线，以此分析均匀半透明平面上的菲涅耳单缝衍射屏上的相对光强分

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。

The two mechanisms are used to modify the logarithmic-spiral slide curve. The example analyses show that the accuracy of this thesis's modified logarithmic-spiral mode is greatly enhanced.

对目前使用的对数螺旋滑移面进行了修正，实例分析表明，本文修正模式准确程度大大提高，不需经过大量试算。

Experiment results show that equiangular spiral antenna basked EBG structure has a wider frequency bandwidth, higher gain, and larger front-to-back ratio than a traditional spiral antenna with ground plate; and also the thickness of antenna is reduced obviously.

实验结果表明，背衬EBG材料的等角螺蜷天线与传统的带反射板的等角螺蜷天线（辐射器离反射板的高度为λ／4）相比能够同时提高增益、展宽带宽、改善前后辐射比，并且显著减薄天线的厚度。

When the centre line of road is spiral curve,the edge lines(equidistance lines of centre line) are not spiral curves,which makes it difficult for construction location.

在各种曲线组合当中，卵型曲线中的回旋线曲率半径不是从无穷大开始，最为复杂。

Up to now, the use and manufacture of spiral fluted taps is seldom seen in our country, The design of spiral fluted taps with a large diameter is still in the reseach stage.

目前，螺旋槽丝锥在我国的制造和应用还很少，而大直径螺旋槽丝锥的设计至今仍处于探索阶段。

These rules reflect some inherent feature of self and nonself, and they are the basic detection criterion of GECISM.

这些规则反映了"自我"和"非我"的内在特征，是GECISM进行"非我"检测的判据。

Until today, the media from China and the outside world still uses the term "Post 89". Regardless to whether it is for commercial gimmick or convenience, everybody still remember "Post 89", a term which carries a strong Cantonese accent.

时至今日，国内外艺术媒体还是在沿用&后八九&这个称谓，不管当初是为了商业噱头还是容易上口好记，反正大家现在是记住了&后八九&这个广东口音很重的词。