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41.
为达到合肥光源二期工程通用模式的设计流强,在储存环上选择垂直方向β函数比较大的位置增加一组八极磁铁。该组八极磁铁对水平方向动力学孔径影响很小,虽然垂直方向动力学孔径明显减小,但仍然大于物理孔径,不会影响束流的注入积累过程。该组八极磁铁产生的垂直方向振荡频率分散可以提供ms量级的Landau阻尼时间,将明显增强抑制垂直方向束流集体不稳定性的能力。该组八极磁铁投入运行后,合肥光源注入积累过程明显改善,注入流强从无八极磁铁时的约100 mA提高到330 mA左右。 相似文献
42.
William Basener 《Topology and its Applications》2006,153(14):2760-2764
We review some properties of transverse disks and use symbolic dynamics to determine rotation vectors from the return map to a transverse disk. We also prove connections between the symbolic dynamics and Nielson equivalence of orbits. 相似文献
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A new design of the U-type resonator is described. In this way, a laser beam with symmetrical intensity profile (regarding to a symmetry plane) can be extracted from an active medium that exhibits gain asymmetry along one of the transverse directions. The whole area of the active medium cross-section can be used, and consequently the laser efficiency will be increased. This resonator structure was applied for efficiency power extraction (as a low order TEM modes laser beam) from a DC excited transverse flow CO2 laser with cylindrical geometry. Although the cross-section area of the discharge was entirely used (including the cathode fall region), a symmetrical intensity profile of the laser beam (regarding to the two orthogonal symmetry planes) was obtained in the near field as well as in the far field; the gain asymmetry along the flow direction was compensated by the gas circulation fluidodynamical circuit with two counterflowing discharge channels. A double-U optical resonator was introduced in order to provide a laser beam with axial symmetry.For the practical construction of these two types of optical resonators we have developed two new types of 90° deflection elements: the first one, which does not reverse the image (and which has the properties of the pentaprism), and the second one, which rotates the image with 90° angle. Both elements exhibit good focusability if they are equipped with two concave mirrors. 相似文献
45.
对氧碘化学激光器的单重态氧发生器(SOG)进行了改进,采用横向射流方式,并对该横向射流式单重态氧发生器的性能进行了检测。实验中过氧化氢碱溶液温度控制在-16℃左右,氯气流量为530mmol/s,He与氯气的流量比为3;采用PS法测量单重态氧分子的产率,吸收法测量氯气的利用率和相对水含量。得出如下结论:在不使用冷阱和分离器的情况下,最高单重态氧分子产率达到58%, 氯气利用率在80%以上,相对水含量小于等于0.5;气体达到最大流量时,发生器仍然能稳定地工作。 相似文献
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根据冻土弹性波测试要求,研制了一种测试冻土用的500kHz纵波,横波1-3及2-2连通复合超声换能器,其灵敏度高,频带宽,声阻抗低,波形简单及脉冲波形前沿徒削,亦适用于其它介质力学特性测试。文章介绍了换能结构原理及测量系统特性,实测了不同含水量(7%-25%)及负温(-2℃--20℃)条件下兰州黄土试块的纵,横波声速,获得很高测量精度(10ps级)。 相似文献
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By using the Quantum Monte Carlo simulation; the electric properties of a nanowire, consisting of a ferroelectric core of spin-1/2 surrounded by a ferroelectric shell of spin-1/2 with ferro- or anti-ferroelectric interfacial coupling have been studied within the framework of the Transverse Ising Model (TIM). We have examined the effects of the shell coupling Js, the interfacial coupling JInt, the transverse field Ω, and the temperature T on the hysteresis behavior and on the electric properties of the system. The remanent polarization and the coercive field as a function of the transverse field and the temperature are examined. A number of characteristic behavior have been found such as the appearance of triple hysteresis loops for appropriate values of the system parameters. 相似文献
50.
M. Platte 《Ultrasonics》1985,23(3):113-118
A new type of piezoelectric polymer hydrophone for the frequency range above 1 MHz is described, which consists of a needle, coated with a thin layer of polyvinylidene fluoride. The sensitive area is a small polarized zone of the polymeric material around the needle point. Special properties, caused by the constructive design of this ‘needle hydrophone’, are its non-directivity in a wide angular range, and high spatial resolution of the ultrasonic sound field pattern. Construction and performance are compared with other types of piezoelectric polymer hydrophones. Some possible applications are discussed. 相似文献