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Through Hilbert transform, a signal's plane trace can be get. There are two frequencies in the tested signal, so the signal's plane trace may be looked as the track of the out pole's end when two poles rotate around parallel axles. Using the knowledge of motion synthesis in theory mechanics, a formula to describing the change of plane trace's step length and angle for two-frequency be get. So we may prolongate the tested signal's plane trace from the echo's initial arriving moment, and get a certain length of the signal's prolongation.

通过Hilbert变换可得到测试信号的平面迹线，测试信号中只含有两个频率成分，视为双频信号，双频信号的平面迹线相当于两连杆绕平行轴转动时外杆杆端迹线，利用理论力学中运动合成和瞬心知识，推导出双频信号平面迹线步长平方满足余弦线性复合函数，而迹线转角可视为线性变化，据此可对回波到来之前的测试信号平面迹线作延长，得到一定长度的信号延展段，信号延展段与实测段作差可得到一次、二次回波的第一个波峰值。

This thesis includes two parts. One part studied the two photon excited luminescent properties of thirty pyridinium compounds in solution, another part studied the two photon excited luminescence properties of HMASPS and HEASPS in polymer matrix.

论文分为两个部分：第一部分研究的是吡啶盐溶液的双光子上转换性质，第二部分研究的是吡啶盐HMASPS和HEASPS在聚合体系中的双光子上转换性质。

Adjacent helical chains are racemic. The Ag atom is linked to two nitrogen atoms of the 2-pyridyl and 4'-pyridyl groups from two different 2,4'-bpy ligands as well as to the oxygen atom of the counterion. In 17 and 19, the adjacent helical chains are linked to wavy two-dimensional network structures by the nitrate counterions.

相邻的螺旋链间是外消旋的，Ag 原子与分别来自两个不同2，4'-联吡啶的2-吡啶基和4'-吡啶基的氮原子以及阴离子的氧原子配位，在配合物17和19中，相邻聚合螺旋链被硝酸根离子桥连接起来，变成了一个波浪形的二维网络结构；配合物18是首次通过无桥连配体支持的Ag ××× Ag键将相邻螺旋链连接成二维非穿插的网络结构。

Secondly,two regulatable current sources for exicitation of magenetic powder dynamic brake are studied respectively with buck and interleaving two-transistor forward topology. In the power supply with interleaving two-transistor forward topology design,simulations are implemented with Saber simulator,thus the best parameters are achieved which ensured the stability and dynamic characteristic.

二、分别用 BUCK 式和交错并联的双管正激式电路拓扑，研制了磁粉制动器的直流励磁电流源，其中对于交错并联双管正激式的电路进行了基于 Saber 的仿真，确保了电路参数的选取能够保证电路稳定性与动态性能要求。

In this DVD, Gil Rimmer simultaneously develops two characters, Francis and Paulo, who are classic pugilists in a fictional turn of the century metropolis. This first in a two DVD series focuses on creating the faces and heads of the two fighters, using dynamic silhouettes, rhythms, graphic design and composition principles.

在本DVD中GIL同时制作了两个卡通角色，它们是Francis and Paulo，两个century metropolis出品科幻小说的著名的拳击手，本DVD是一套2DVD中的第一张，着眼于创建两个角色的头部与面部，其中应用了动感轮廓，图形设计，合成原理等。

The reconstruction problem is ill-posed, so two optimal criterions, the least module and the smoothness criterion base on Tikhonov regularization technique, are introduced into reconstruction algorithm. Many regularization parameters choice strategies are investigated, and the TPA(Two—Parameter Algorithm) strategy which is based on the Morozov discrepancy principles, is implemented in two regularization reconstruction algorithms.Numerical experiment results show that the nonnegative and smoothness constraint condition can overcome the difficulty of iteration semiconvergent, preconditioned technique can improve convergence rate and reconstruction accuracy, smoothness regularization criterion can meliorate ill-posed problem of reconstruction and enhance iteration stability, and the TPA is an effective strategy of regularization parameters choice.

数值试验表明：在共轭梯度法中引入非负约束和光滑约束改善了迭代的&半收敛&性，非负约束保证了解的非负性，光滑约束抑制了重建解的振荡现象，约束算法的重建精度与无约束算法相比大幅度提高；在约束共轭梯度重建算法中引入预优技术，可以加快算法的收敛速度，提高迭代的稳定性和重建精度；引入光滑准则的正则化技术可以有效改善图像重建问题的不适定性，加快迭代的收敛速度，提高迭代的稳定性和图像重建质量，计算正则参数的TPA算法在闪光照相图像重建中是有效的。

Two types of sensilla trichodea, two types of sensilla chaetica, two types of sensilla basiconic and one type of Bhm bristles were distinguished with the shapes and distribution of sensilla.

触角感器共有4种，分别为毛形感器、刺形感器、锥形感器、Bhm氏鬃毛。其中，毛形、刺形、锥形感器各有两种类型。

Two weeks ago, those two did not want to leave their little hideaway at the bottom of their cage, Sher Aqa said, pointing to two monkeys.

Omar指着两只猴子说：&两周前，我把它们俩放出笼子的时候，它们居然都不愿意出来。&

The water chamber takes the shape of tilting cube, in favor of uniform distribution of cooling water on tube plate surface. The tube bundle is divided into two groups of zygomorphy according to the bisection system and it has eight support clapboards. The siphonopore center of each clapboard increases a certain distance corresponding to that of two tube plates and the cooling tube takes the shape of arch. The two-way cooling water of bisection flows through the condenser in opposite direction so as to improve the distribution of heat load for tube bundle. Around the throat of condenser, the final stage low-pressure heater, air extraction tube, intake device of bypass exhaust and the like are deployed.

它的特点是：水室呈倾斜立方体形状，有利于冷却水流在管板面上均匀分布；由于采用对分制，管束相应地分为左、右对称的两组，并且管束设有八块支撑隔板，每块隔板的管孔中心相对于两端管板的管孔中心依次抬高一定的距离，以使冷却管呈拱形状；对分制的两路冷却水以相反方向流过凝汽器，从而改善管束的热负荷分布；在凝汽器喉部布置了末级低压加热器，抽汽管道及旁路排汽接受装置等。

In view of the operational SITIO problem is faced by the system decision-maker daily, the dissertation uses two chapters to address this class problem applied in two situations respectively. One of two situations is assumed to be R-System.

山于作业层的随机联合优化问题几乎是系统决策者每天都要面对的问题，本文用两章篇幅分别讨论了两种应用背景下解决这类问题的过程。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。