查询词典 circular

The influence of free surface on tunnels is discussed.The influence of blasting vibration on fresh concrete lining is studied. The finite element method is employed to analyze the spatial distribution of temperature and thermal stress of fresh concrete lining, the wave function expansion method is used to study the interaction of blasting seismic wave and the circular tunnel with lining, thenthe safe PPV of fresh concrete lining with different age is decided by taking into account the thermal stress of concrete lining. Using the conformal mapping method, the influence of blasting vibration on the arch tunnel with lining is studied and the safe PPV of concrete lining is deduced under different incident angle.

研究了爆破振动对新浇混凝土衬砌的影响，采用有限元法求出了圆形洞室新浇混凝土衬砌内温度和温度应力在空间上的分布及其随时间的变化，采用波函数展开法求解了爆破地震波与有衬砌圆形洞室的相互作用，获得了考虑新浇混凝土衬砌内温度应力前提下不同龄期的新浇混凝土衬砌的安全振速；利用保角变换研究了爆破振动对直墙拱形有衬砌隧洞的影响，得到了爆破地震波以不同角度入射时混凝土衬砌的安全振速。

The Radar Cross Section of an S-shaped circular wave guide and that coated with absorber layer on the inner wall are computed by the fast Iterative Physical Optics method using algorithms of initial value succession and Forward-Backward Iterative.

在此基础上采用初值继承算法和前后向迭代结合的快速IPO方法计算了采用S弯和在腔体内壁涂敷吸波材料对腔体雷达截面的减缩效果。

Characteristics of axial light intensity of planar wave diffractedby small circular aperture.

陈建农，闫金良，王德法，于永江，"受孔径约束抛物面折射系统的分数傅里叶变换"，中国光学快报 5，

Complex method and multi-polar coordinate transformation are used here to study the scattering problem of SH -wave to the circular cavity in the half-space with elastic constraints acting on the straight boundary.

利用复变函数法和多极坐标移动技术求解讨论弹性约束边界半空间内浅埋圆孔对稳态入射平面SH（shearing horizontal，反平面剪切）波的散射问题。

The eigenmedes are left--hand or right--hand circular polarised wave,the dipole radiation is closely related to the chirality parameter.

结果表明：手征媒质中存在电磁模式分裂，其本征模为左、右旋圆极化波，偶极辐射性质与旋波因子密切相关。

The new antenna has the advantages of sim ple structure, easy feeding and a wide frequency range, and circular polarized wave. The characteristics are m uch better than a bifilarbackfire helicalantenna, a shortbackfire antenna and a backfire...

它具有结构简单、馈电方便、遮挡小、频带宽、增益高且易于产生圆极化波等优点，性能远优于带相同接地板的螺旋天线、普通短背射天线以及单线背射螺旋作馈源的短背射天线。

Analysis of high-power millimeter wave circular waveguide TM01-TE11 mode converter.

牛新建，李宏福，谢仲怜。高功率毫米波圆波导TM01-TE11模式变换分析。

There are three parts in our design: first, the dual-band branch line coupler provides two equal-power signals with 90° or -90° phase difference in each operating band. Second, the wideband switching circuit controls the two output powers of branch line coupler to excite the antenna structure for producing linear polarization wave or circular polarization wave. Third, the L-shaped fed conventional planar patch antenna is provided to overcome the coupling effect.

整体架构包含三个部分：L形电容耦合馈入式平面天线是为了克服平面式微带天线窄频的缺点；双频枝干耦合器提供天线在操作的两个频率点上各输出两组相差正九十度与负九十度的讯号，最后宽频的切换电路是将枝干耦合器的两组讯号作分配用以激发不同方向的天线以产生线性极化模态或同时激发两个垂直的天线以产生圆形极化模态。

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。

This means that it's not a circular coordinate system.

这意味着，它不是一个圆形坐标系统。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。