连续隔振浮筏系统功率流研究

建立了多扰源连续隔振浮筏系统的动力学模型,并考虑基础及浮筏弹性,推导了此类复杂耦合系统的动态特性方程及功率流表达式,从能量的观点揭示了连续隔振浮筏系统的隔振机理,并编制了相应计算软件,进行了数值计算及理论分析,揭示了连续隔振系统结构参数对其隔振性能的影响。     

通过声辐射模态研究结构声辐射的有源控制

以简支平板为例,通过声辐射模态建立了弹性结构声辐射的有源主动控制策略。并分析了声辐射模态的数学和物理意义。研究发现在中、低频时,声辐射模态对应的辐射效率随着模态阶数的增加而迅速降低。在此基础上,本文提出了一种新的控制策略,即抵消前k阶声辐射模态的伴随系数,使得前k阶声辐射模态的声功率为零。本文以点力作动器作为控制力源进行了数值计算研究。     

Bonding Interface Imaging and Shear Strength Prediction by Ultrasound

The propagation of a longitudinal ultrasonic wave normally incident upon an adhesively bonded structure is studied. The structure consists of adherend and adhesive layers with finite thickness. Interfaces between adherend and adhesive are regarded as distributed springs. Theoretical and experimental results show that resonant frequencies of the bonded structure vary sensitively with the interface stiffness constants and adhesive thickness, and these interface characteristics are inversed by the simulation annealing (SA) method. Furthermore, the distribution image of interface stiffnesses is compared with the state of fracture interface, and quantitative prediction of shear strength is achieved based on the distribution of interface stiffnesses and adhesive thicknesses by using a back-propagation neutral network. The average relative error of the shear strength from prediction to real value is 10.7%.     

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针对准中性Vlasov-Poisson系统中多尺度物理参数共存的问题开展研究,采用渐近保持格式推导出与Vlasov方程相耦合的Poisson方程。数值模拟了一维等离子体在真空中的膨胀,比较了渐近保持PIC算法与传统PIC算法模拟结果的异同。结果表明：两种算法在满足多尺度中小尺度量限制的前提下,其结果保持高度一致;且在克服小尺度量束缚时,渐近保持PIC算法依然可以正确地模拟等离子体的物理行为,大大节省了计算时间。     

HIRFL-CSR电子冷却束流位置测量系统

高效率的电子冷却过程, 要求电子束与离子束位置平行且重叠。 为了同时测量电子束与离子束的位置, 在HIRFL CSR电子冷却装置上研发了以容性圆筒形极板为感应电极的束流位置探测系统。 系统测量束流通过探针时产生的脉冲感应信号, 并进行傅里叶变换得到频谱信号, 分析4个不同电极上频谱信号强度获取束流的位置信息。 测量结果表明, 该束流位置探测系统测量准确, 为定量研究储存环离子累积和电子冷却过程与两种束流相对位置及角度的依赖关系提供了条件。 The efficient electron cooling requires that the ion beam and electron beam are parallel and overlapped. In order to measure the positions of ion beam and electron beam simultaneously, a beam position monitor system is developed for the HIRFL-CSR electron cooler device, which probe consists of four capacitive cylinder linear cut poles. One can get the both beam positions from the picking up signals of four poles by using Fourier transform(FFT) method. The measurement results show that the beam position monitor system is accurate. This system is suitable for investigating the relation between electron cooling processing and the angle of ion beam and electron beam.     

Determination of Thickness of an Inaccessible Thin Film under a Multilayered System from Natural Frequencies

We investigate the relationship between natural frequencies of a multilayered system of different elastic materials and the thickness of the undermost thin film. The natural frequencies are numerically calculated from the reflection coefficient of a sample system of ＂steel-epoxy resin-aluminium-thin polymer＂ with normal incidence. Strain energy ratio is defined and calculated to give the physics explanation why some frequencies are sensitive to thickness of the thin film in certain range. Experiments of three specimens indicate that the measured natural frequencies agree well with the theoretical ones. It is found in our experiments that the ratio of the lowest film thickness to wavelength is about 1/5. The average relative errors for the inverted polymer film thicknesses are found to be 11.8%, -4.8% and -1.3%, respectively.     

基于可见-近红外光谱技术预测茶鲜叶全氮含量

为快速无损监测茶树氮素营养及其生长状况,基于可见-近红外光谱技术建立了茶鲜叶全氮含量的预测模型。以茶鲜叶为对象,田间试验使用便携式光谱仪采集叶片漫反射光谱信息,通过不同预处理和统计分析,建立茶鲜叶全氮含量预测的光谱模型。试验共采集111个样品,其中86个样品作校正集,25个样品作预测集。通过一阶导数与滑动平均滤波相结合的预处理方法,用7个主成分建立的偏最小二乘模型最好,其校正集均方根误差(RMSEC)为0.097 3,预测集的相关系数为0.888 1,预测均方根误差(RMSEP)为0.130 4,预测的平均相对误差为4.339%。研究结果表明,利用可见-近红外光谱技术可以很好地预测茶鲜叶全氮含量,对于快速实时监测茶树长势和施肥管理具有重要指导意义。     

兰州重离子加速器冷却储存环

 兰州重离子加速器冷却储存环HIRFL-CSR,是一个多用途、多功能的双冷却储存环同步加速器系统,由主环CSRm和实验环CSRe构成,并以兰州重离子级联回旋加速器HIRFL作注入器。CSR利用高频变谐波的方法,将重离子束的能量从7～25 MeV/u同步加速到２00～1 000 MeV/u,同时利用重离子储存环中空心电子束冷却技术将束流品质提高１个数量级,并通过储存环的快引出及慢引出,提供多种类的重离子束以及放射性次级束(RIBs),以开展范围更广精度更高的物理实验。该装置于2007年投入运行,已取得了重要的运行结果,如实现了剥离注入与多圈注入、空心电子束对重离子束的冷却与累积、变谐波宽能区同步加速、等时性环型谱仪、RIBs的产生收集与ToF高分辨质量测量以及高能重离子束的变能慢引出等。     

Configuration of the valence neutrons of 17B

The reaction cross section of ~(17)B on ~(12)C target at(43.7±2.4)MeV/u has been measured at the Radioactive Ion Beam Line in Lanzhou(RIBLL).The root-mean-square matter radius(R_(rms))was deduced to be(2.92±0.10)fm,while the R_(rms)of the core and the valence neutron distribution are 2.28 fm and 5.98 fm respectively.Assuming a"core plus 2n"structure in ~(17)B,the mixed configuration of(2s_(1/2))and(1d_(1/2))of the valence neutrons is studied and the s-wave spectroscopic factor is found to be(80±21)%.     

用于浅层肿瘤重离子治疗的终端束流诊断控制系统

 设计了中国科学院近代物理研究所利用兰州重离子研究装置（HIRFL）进行浅层肿瘤临床治疗试验研究中所使用的束流诊断安全控制系统。该系统包括束流强度监测及保护、剂量测量、扫描波形监测及保护3个部分。系统基于PXI系统及LabVIEW软件,给出了该系统的各部分结构。从系统建立时的多次测试结果以及实际临床治疗试验研究时的长期运行结果来看,该束流诊断控制系统在控制辐照剂量以及安全保护方面能够满足当前重离子加速器浅层肿瘤临床治疗试验的基本要求,为试验研究的顺利进行提供了可靠的保证。