查询词典 frequencies

It is difficult to calculate the natural frequencies of silent chain drive accurately because of the discontinuity of its structure and the polygonal effect.

其中心线的位置存在着周期性的变化，这种变化使得链节和链轮的接触与脱离是在一瞬间完成的，链条存在着剧烈的横向振动。

Next, determining natural frequencies of the structure is transformed as a problem belonging to finding a characteristic value of characteristic function in the above differential equation.

把该结构的固有频率问题归结为求解该微分方程特征函数的特征值问题。

Then based on the characteristic equation, the effect of the position of intermediate support on the natural frequencies of the beam is discussed.

根据频率方程讨论了中间支承位置变化对梁固有频率的影响。

Methods Chromosome analysis technique was used to study sister chromatid exchange frequencies of in-vitro-culture blood lymphocyte.

采用染色体分析技术，对体外培养的外周血淋巴细胞姊妹染色单体交换频率进行观察。

Methods Chromosome analysis technique was used to study sister chromatid exchange frequencies of in-vitro-culture blood lympho-cyte.

采用染色体分析技术，对体外培养的外周血淋巴细胞姊妹染色单体交换频率进行观察。

The analysis of sister chromatid exchange frequencies is a useful tool for the study of damages in genetic material of human beings induced by enviromental mutagens and carcinogens.

用荧光加Giemsa术区分姐妹染色单体，分析了13名中年男子外周血淋巴细胞的SCE，比较吸烟者和不吸烟者"自发"的和用丝裂霉素诱发的SCE频率变化。发现吸烟者的SCE频率(8.33±1.08)显著地高于不吸烟者(4.41±0.72)，p.001。

Spectral aliasing is caused by interference between two frequencies such the luminance and chrominance signals.

光谱混叠是由两个频率如亮度和色度信号频率之间的干扰引起。

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。

Measurement of genes and gene-frequencies can also be problematic, because a simple statistical correlation can be open to charges of circularity.

量测基因跟基因普及性可能也会有问题，因简单统计的相关性可能出现圆圈。

The gene frequencies of novel SNPs had no significant difference between CML and control people.

对CML和对照组的多态性频率的比较表明，这些新发现的SNP在两组间无显著差异。

We are forbidden from giving money to these shoeless, skinny children, as this will perpetuate begging.

向光着脚，骨瘦如柴的孩子施舍是不可以的，因为要招来无休无止的乞讨。

It would be hard not to fall victim to some sharpeyed policeman.

要想不被某个目光锐利的警察抓到，谈何容易。