单频的

The analytical solutions for the ABCD matrices of uniform transmission lines are expanded into matrix infinite series with very simple terms, from which two important properties about the time-domain response of all kinds of transmission lines are obtained. The lines analyzed may have frequency-dependent parameters and arbitrary terminals.

由于网络理论中ABCD矩阵的特殊性质，该方法对非均匀传输线时域响应的分析具有更大的优越性，能分析的传输线可以具有频变参数和任意负载终端，给出了计算非均匀传输线ABCD矩阵的两种方法，一种是将非均匀传输线等效为一系列由长度很短的均匀传输线构成的子网络的级联，另一种是用单步法直接求解ABCD矩阵所满足的微分方程。

Multicarrier modulation in data transmission is discussed in the fourth chapter. The performance of MCM and single tone modulation over twisted pairs is compared. Discrete multitone modulation is used in ADSL system. A new variable constellation TCM method is proposed, It can adapt to the subchannel capacity automatically. The simulation results prove that this method is quite effective.

第四章讨论了多载波调制技术在数据传输中的应用，针对市话信道的具体传输环境，比较了单载波调制与多载波调制的性能；针对ADSL传输的目标，采用离散多频音DMT技术，独立提出一种新的星座图变化的格状码方案VCTCM，能动态地适应不同子信道的传输能力，给出的计算机仿真结果表明该方案有较好的效果。

Based on the laser longitudinal mode splitting theory, a novel scheme of dual-frequency laser with large frequency-difference is presented using electrically controlled birefringence of liquid crystal, and the transmitted resonant mode splitting by birefringent of Fabry-Perot etalon has been analyzed theoretically. A new element of liquid crystal Fabry-Perot etalon is designed and fabricated, which serves as aselector and splitter of both laser longitudinal modes and Fabry-Perot etalons transmitted resonant modes. Two different experimental systems of laser-diode end-pumped Nd:YAG laser have been set up using two different LDs, and the transmission of liquid-crystal cell have been measured. When the empty LCFP is inserted in the cavity of high-power LD pumped Nd:YAG laser, the oscillation of a single laser longitudinal mode have been observed, such a result shows that the designed and fabricated LCFP element is capable of selecting single axial mode. While an anti-reflected liquid crystal cell is inserted in the cavity of Nd:YAG laser end-pumped by the high-power LD, it is difficult to confirm weather the laser longitudinal modes have been spitted or not. The subject is summarized in this thesis and the improvement of the project has been presented.

论文以激光纵模的分裂理论为基础，提出了可望获得几十GHz甚至上百GHz的液晶电控双折射双频Nd：YAG激光器的总体方案，并对用双折射效应分裂F-P标准具透射谐振模进行了理论分析；设计并加工了一种集激光纵模选择、激光纵模分裂和F-P标准具谐振透射模分裂于一体的多功能元件——液晶电控双折射F-P标准具；建立了两种不同功率激光二极管端面泵浦的Nd：YAG激光实验系统，并对液晶盒的透射性质进行了测试；将未灌注液晶的空液晶F-P摘要标准具插入大功率LD泵浦Nd：、叭G激光谐振腔内，观察到了单纵模激光输出，说明所设计和加工的液晶F一P标准具具有纵模选择能力；将镀有增透膜的液晶盒插入大功率LD泵浦Nd八7AG激光谐振腔内，是否产生了激光纵模分裂现象还难以确定。

The accelerator physics problems of the upgrading program were discussed here, which include the space charge effect on the very low energy beam line, non-parity acceleration at the injector cyclotron SFC, longitudinal match between two cyclotrons, strong magnetic field leakage afluence on the beam transfer at low and very low energy, residual first harmonic magnetic field in the main cyclotron SSC injection region, the low efficiency and beam quality of heavy ions after through stripper etc.

主要问题有：超低能束流传输的空间电荷效应的影响，扇聚焦回旋加速器SFC高频加速电压不对称对束流轨道的影响，用半频聚束的方式补偿两台回旋加速器的纵向不匹配，前束线上聚束器的工作模式的选取，强杂散磁场对超低能和低能束流传输的影响，分离扇回旋加速器SSC注入区过垫补磁场对注入束流轨道的影响，SFC和SSC的单圈引出，重离子通过剥离膜后的束流损失和束流品质的变坏等。

This kind of gratings can be kept in the material for a long time. A mode of molecular reorientation was used to explain the formation mechanism of these gratings and it is well consistent with our experimental results. 3. Three kinds of azobenzene polymers P , P (MMA-co-GY7) and P (MMA-co-GO13) were synthesized by radical polymerization. High-density optical storage and the three-dimension (3D) microstructures in the azobenzene polymer films were presented. Twenty gratings have been stored on the same spot in our material. It is twice as many as the best recording that has been reported. It is the first time, a rectangular microstructure and a complicated double layers nesting six-pointed star microstructure are inscribed in it by using a simple two-wave couple setup.

采用共聚反应设计合成了单偶氮苯聚合物P、双偶氮苯聚合物P（MMA-co-GY7）和P（MMA-co-GO13）三种聚合物，研究了偶氮苯聚合物薄膜中的高密度光学存储和3维微结构，成功的将20套光栅储存在样品中同一个点上，是已有报道的两倍；并首次用简单的2波混频光路在该材料中刻写出长方格子和六角星型的微结构，在制作多重不同周期不同角度的高密度光栅结构实验过程中，发现不同周期光栅的刻写顺序对整个微结构形成的最终结果具有决定性的影响，并用相衬显微镜观察了这些微结构图像。

Based on one-cycle control having such merits as anti-perturbation of source, fast dynamic response, robustness, constant frequency, but when converter works in light load its power factor becomes very poor. The modified OCC was proposed, adopting feed-forward compensation control improves influence of power factor at light load, further study adopting independence saw tooth wave completely eliminate influence of power factor at light load.

基于单周期控制有源前端变换器具有抗电源扰动能力强、动态响应快、鲁棒性强、恒频控制等优点，但在轻载时变换器的功率因数变差，提出了改进OCC策略，采用前馈补偿控制改善轻载时对功率因数的影响，进一步研究采用独立的锯齿波电路完全消除轻载时对功率因数的影响，建立改进OCCAFE变换器的数学模型。

Therefore, the choice of single mode in the examination and the frequency-thick band of mode has been given a particular illumination separately in the paper, following a relative numerical simulation. And a multi-cyclical sine signal modulated by Hanning window is used to simulate the excitation wave, and then an inspected ring of nodes is established to receive the echo, finally how the length of the circumferential cracks, the width of the axial cracks and the degree of the thickness-reduce effect the result is explained through the analysis of the result, further more, the reflection factor in the defect has been calculated.

因此，本文也就单一检测模态的选择以及模态频厚积段的选择分别予以了阐述，并有针对性的进行了数值计算：应用Hanning窗调制的多周期正弦波模拟单音频激励信号，并设置监测质点环接收回波，通过分析说明了管道的周向裂纹、轴向裂纹以及点蚀缺陷对缺陷回波所产生的影响，并进一步计算了缺陷处的反射系数。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷