Novel model of FM-noise conversion in a UMZI using RF external phase modulation of lasers: Theoretical and experimental results

In this paper, we propose and demonstrate a new and original model for theoretical calculation and experimental measurement of the noise power spectral density (NPSD) in phase-modulated optical links. The phase modulation is operated in the RF frequency range by an external phase modulator. The NPSD is derived for the first time in interferometric systems, by considering all effects such as the 1/f FM noise of the laser and white noise applied to light from a 1550 nm DFB laser, with phase modulation. The results show for the first time the influence of the phase modulation index, modulation frequency and interferometric delay in the phase-to-intensity noise conversion. The experimental and simulation results of conversion of FM-noise to intensity noise in an optical link by considering the external RF phase modulation are shown with good agreement.     

BEPCII直线加速器相控系统设计研究

为了补偿由于各种因素引起的微波相位漂移,BEPCII直线加速器需要建立微波相位反馈控制系统.能量最大法将用来确定每台功率源的最佳相位.沿直线加速器速调管长廊铺设相位稳定同轴线提供相位参考.现在已经完成了关键部件,如PAD单元、IfA 单元的开发.搭建了相控最小系统对系统进行了验证.     

中物院远红外自由电子激光实验研究

中国工程物理研究院基于射频直线加速器技术的远红外自由电子激光(FIR-FEL)实验取得阶段性进展,于2005年3月24晚8时30分首次出光, 并多次重复. 中心波长115μm, 谱宽1%.介绍了实验系统的主要组成部分和主要实验结果.     

X波段盘圈加速结构热阴极微波电子枪的研究

介绍了采用盘圈(DAW)加速结构在11.43GHz下研制的热阴极微波电子枪注入器，分析了注入器中DAW加速结构支撑杆对于微波特性的影响以及加速结构中的模式重叠问题. 针对该结构的强腔间耦合以及次临近耦合不能忽略的特点，对其调谐方法进行了分析研究.给出了该长腔链热阴极微波电子枪注入器的物理设计及粒子动力学计算结果，电子能量为5—6MeV，脉冲流强为40mA，电子束发射度为3.4πmm.mrad. 该微波电子枪的加工焊接已经完成，文中给出了其冷测结果.     

Modeling of RF plasma torch with a metallic tube inserted for reactant injection

Flow, temperature, and electromagnetic (EM) fields in a radio-frequency thermal plasma torch designed for the preparation of superconducting powders or films have been analysed by using a new two-dimensional modeling approach with the electric field intensity as the fundamental EM field variable. The insertion of a stainless steel injection tube into the torch leads to large induction currents in this tube. Although such large induction currents cause pronounced changes of the EM fields near the injection tube, flow and temperature fields are little affected. There exists only one large toroidal vortex in the upper part of the present torch, while the maximum temperature appears at an off-axis location within the coil region.     

三维射频加速腔程序包MAFIA的开发和应用

介绍了三维射频加速器计算机辅助设计(CAD)程序包MAFIA的特点、功能及其应用。用CAD的方法实现了射频加速器特别是非轴对称带耦合腔的加速器的三维腔形设计。同时介绍了节省内存、节约机时的模型方法,使得在中小型机器上运行大程序(八万条)成为可能。文章主要对L波段的加速腔进行了数值模拟,并和实验进行了比较,结果符合较好;通过三维数值模拟及图形模拟的方法比较了各种形状谐振腔的性能;计算分析了输入耦合腔及高阶模耦合器对加速腔电磁场分布等参量的影响;提出了加耦合器后谐振频率改变的补偿方法。     

退火温度对低温生长MgxZn1－xO薄膜光学性质的影响

用射频磁控溅射法在80℃衬底温度下制备出Mg_xZn_1-xO(x=0.16)薄膜，用X射线衍射(XRD)、光致发光(PL)和透射谱研究了退火温度对Mg_xZn_1-xO薄膜结构和光学性质的影响.测量结果显示，Mg_xZn_1-xO薄膜为单相六角纤锌矿结构，并且具有沿c轴的择优取向；随着退火温度的升高，(002)XRD峰强度、平均晶粒尺寸和紫外PL峰强度增大，(002)XRD峰半高宽(F 关键词： xZn_1-xO薄膜')" href="#">Mg_xZn_1-xO薄膜 射频磁控溅射 退火     

Effect of nonstoichiometry on Raman scattering of VO2 films

We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.     

后退火温度对溅射沉积Pb(Zr0.52Ti0.48)O3铁电薄膜结构和性能的影响

在具有Ti缓冲层的Pt(111)底电极上,用射频溅射工艺在较低的衬底温度(370℃)和纯Ar气氛中沉积Pb(Zr0.52Ti0.48)O3(PZT)薄膜,沉积过程中基片架作15°摇摆以提高膜厚的均匀性。然后将样品在大气中进行5min快速热退火处理,退火温度550-680℃。用XRD、SEM分析薄膜的微结构,RT66A标准铁电测试系统测量样品的铁电和介电性能。结果表明,所沉积的Pt为(111)取向,仅当后退火温度高于580℃,沉积在Pt(111)上的PZT薄膜才能形成钙钛矿结构的铁电相,退火温度在580-600℃时结晶为(110)择优取向,退火温度高于600℃时结晶为(111)择优取向。PZT薄膜的极化强度随退火温度的升高而增加,但退火温度超过650℃时漏电流急剧上升,因此退火处理的温度对PZT薄膜的结构和性能有决定性的影响。     

Effects of Amplitude of the Radiofrequency Electromagnetic Radiation on Aqueous Suspensions and Solutions

The effects of radiofrequency (RF) (1–4) and magnetic fields (5–9) on the behavior of aqueous solutions and suspensions have been a popular subject in recent years. The mechanism of the magnetic “water memory” effect, though, is still largely unknown (5). In this work, we present evidence that the primary “receptor” of the electromagnetic radiation is a gas/liquid interface. Gas can be either already present in water or produced by the effects of electromagnetic fields. Perturbed gas/liquid interfaces require hours to equilibrate. Certain RF and magnetic signals also produce reactive oxygen and hydrogen species (superoxide, hydrogen peroxide, hydrogen, atomic hydrogen). The perturbed gas/liquid interface modifies the hydrogen bonding networks in water and also the hydration of ions and interfaces. Careful outgassing removes all of the effects of the electromagnetic fields, including the magnetic memory effect. The amplitude of the applied field influences the observed effects. Different amplitudes of RF radiation perturb the interfacial water in different ways and consequently affect the behavior of colloids and ions in specific manners. For instance, the bulk and template precipitation of calcium carbonate, zeta potentials of suspended colloids, rate of dissolution of colloidal silica, and attachment of colloidal silica to metal surfaces are modified in specific ways with the low amplitude or high amplitude RF treatments described in this paper. The solubility/diffusivity of gas species is also modified in a different manner, and it is probably at the core of the specificity of the RF amplitude effects.