有环的

At the same time, the center conditions and bifurcation of limit cycles at the origin of the quintic polynomial system are also investigated.

第二章研究了一类三次多项式系统由细焦点分支出极限环的问题，证明了该系统有12个小振幅极限环，证明过程是符号和代数的，且焦点量的表达式相对简单。

The First part is analysis and design of the subharmonic sampling phase-locked loop.

所设计的锁相环的采样鉴相器采用高性能集成电路，环路滤波器采用二阶有源比例积分滤波器，并设计了扩捕电路以提高锁相环的可靠性。

The trend was that the pollution of particle-bound PAHs under the viaduct was more serious than on th...

同时，同一地点颗粒物及其中多环芳烃连续24h的监测结果表明，在24h内，大气中颗粒物及其中的多环芳烃含量有规律的波动，在清晨、下午出现两个高峰。

While there are the same material properties, shapes and similar boundary conditions, the field distribution of the former can be solved analogically by the later one.

密绕线匝的铁氧体电感器磁场强度H可认为仅有环向分量，若选择H为自由度，则成轴对称场分布；加载环向电流的电感器选择矢量磁位A为自由度时也呈轴对称分布，该文推导了这两类磁场在各自自由度下满足的微分方程。

As the number of fused benzo rings increases, the total energy decreases andthe maximum absorption band shiftes to longer wavelength.

当酞菁环上稠合的苯环数目依次增加时，体系总能量〓有明显的降低，最大吸收峰变化的趋势都是红移，其中ZINDO／s方法计算得到的红移值达到72nm。

They suggested that radicals with a double bond 13 to the carbon bearing the peroxy groups (which can only arise from acids containing more than two double bonds) cyclize to form peroxides with five-membered rings.

他们认为连接过氧基的碳原子有一个双键的游离基(只有多于两个双键的酸可形成)环化形成五元环的过氧化物。

Fifty-seven kinds of polycyclic aromatic hydrocarbon were detected by qualitative method,and sixteen kinds of those were mensurated by quantitative method.The results suggested that the average concentration of chry was the highest,21.83 ng/m3;the average concentration of fluoranthene was the second highest, 21.14 ng/m3; the mass c...

并对16种多环芳烃定量测定，结果表明：以屈艹为最高，平均值为21.83ng/m3；荧蒽次之，平均值为21.14ng/m3；苯并芘的质量浓度为14.52ng/m3，不满足GB3095-96中的质量浓度限值。2001～2003年检测结果对比表明，部分监测点空气中多环芳烃的浓度有下降的趋势。

The graticule consisted of a ring of six small diamonds, the diameter of which could be set to correspond with the target span.

这个分划有一个6个小钻石标记组成的环，环的直径可以设定成目标的翼展。

The graticule consisted of a ring of six small diamonds, thediameter of which could be set to correspond with the target span.

这个分划有一个6个小钻石标记组成的环，环的直径可以设定成目标的翼展。

An atom other than carbon in the structure of a heterocyclic compound.

碳环的有一个仅由碳原子组成的环的，如苯

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。