电子储存环中离子俘获不稳定性和高频清洗的模拟

介绍了用强–弱模型对电子储存环中离子俘获不稳定性和高频清洗机制进行模拟研究的结果.模拟结果可合理地解释在合肥光源(HLS)储存环上观察到的现象.     

自由振动台测量TLDEB水箱频率的研究

通过在普通调谐液体阻尼器(TLD)水箱中加入不同高度和宽度的扰流装置,将其改造成调谐液体挡板阻尼器(TLDEB)水箱,以此来控制和提高水箱中第一阶振荡水的频率;并通过自行设计和制作的自由振动台,对TLDEB水箱中第一阶振荡水的频率进行观测与研究.通过比较普通TLD水箱与改造后TLDEB水箱的第一阶振荡水频率可知,TLD...     

含缝拱坝强震失效破坏振动台试验研究

为探究强震时含缝拱坝结构的承载能力及失效路径,在振动台上开展了一系列拱坝模型强震失效破坏试验.基于弹性力-重力准则设计试验,分别进行了不分缝、只有横缝、诱导缝与横缝联合作用这三种情况的振动台模型试验,试验中考虑了材料率相关性的影响,忽略了库水-拱坝相互作用.结果表明,强震作用时由于设缝处的抗拉能力较低,导致缝位置首先发...     

大跨度Y形柱地铁车站结构地震反应研究1）

随着地铁建设的发展,出现了一种新型的结构形式-大跨度Y形柱地铁车站结构,与现有的地铁车站结构完全不同,其空间高大宽敞,环境舒适.为研究该新型地铁车站结构的抗震性能,以北京地铁6号线新华大街站为工程背景,使用FLAC^3D软件建立土与地下结构三维有限差分动力模型,模拟其在新华大街人工波作用下的响应过程,重点分析了车站Y形柱和侧墙的加速度、位移、应变的规律,并与试验结果进行了对比分析,结果表明：数值模拟与振动台试验结果基本一致,体现出了相似的规律性;Y形柱加速度最大位置出现于柱顶端稍下位置,并非于柱顶端;Y形柱分叉位置处应变出现突变,此点相对于柱底的位移最大,且变化率较大,是抗震设计中需要加强的部位;Y形柱加速度、位移变化都会大于侧墙.上述研究成果对提高该类地铁车站结构抗震性能的认识及抗震设计水平提供了合理的参考与指导.     

Complete balancing of the shaking moment in spatial linkages by adding planar noncircular gears

Summary A balancing device is introduced, which can be applied for balancing spatial linkages which contain input links with revolving kinematic pairs. The method consists in adding noncircular gears, proposed earlier to balance planar linkages, for the balancing of the shaking moment of spatial linkages. Some new formulae to determine the parameters are furthermore proposed. As an illustrative example, the method is used to balance an RSS'R spatial linkage.     

Floquet topological phase transition in two-dimensional quadratic band crossing system

We investigate the Hall effects of quadratic band crossing(QBC) fermions in a square optical lattice with spin–orbit coupling and orbital Zeeman term. We find that the orbital Zeeman term and shaking play critical roles in the systems,which can drive a topological transition from spin Hall phases to anomalous Hall phase with nonvanishing(spin) Chern numbers. Due to the interplay among the orbital Zeeman term, spin–orbit coupling, and the shaking, the phase diagram of the system exhibits rich phases, which are characterized by Chern number.     

砖石古塔模型振动台试验的离散元模拟分析

砖石古塔块体间黏结强度较低,受地震作用易产生裂缝后发生破坏,为研究砖石古塔在地震作用下开裂及裂缝发展机制,以玄奘塔1/8缩尺模型结构为对象,建立离散元模型,计算了地震波激励下结构的加速度及位移反应,与振动台试验结果进行对比,分析了塔体开裂破坏全过程。结果表明,数值计算所得结构的加速度及位移反应与振动台试验结果一致,当地震烈度较低时,两者顶层位移变化曲线基本一致;烈度提高后,塔体开裂导致结构动力响应的计算值与试验结果出现差异,但两者的变化规律相同。在地震波激励下,塔体首层先开裂,随地震烈度的提高延伸至中部塔层,块体第2层出现阶梯状错动,模型损伤过程与试验裂缝发展状况基本吻合。研究结果为砖石古塔地震损伤及破坏过程分析提供了参考。     

摄像测量在平台微小晃动量测量中的应用方法研究

平台在三维空间中的微小晃动反映到二维像平面上就是像点的变化。本文提出基于摄像测量学的小角度测量方法。通过固连在平台上的CCD像机对惯性空间中静态基准的实时观测,解算得到由于平台微小晃动引起的像机姿态变化量;利用固连关系得到平台的小角度变化量,并通过静态和动态实验证明了该方法准确可行,在36′晃动幅度下,测量精度优于5″。该方法在保证精度前提下,可以降低系统硬件成本,可用于修正车载式光学测量设备的平台晃动误差,具有一定的理论研究意义和工程应用价值。     

Rapid and Simple Determination of a Cationic Surfactant by Adsorption Induced by Vigorous Shaking

A rapid and simple method for the determination of a cationic surfactant is described. The method is based on the formation of an ion associate with tetraphenylporphinetetrasulfonic acid (TPPS) and zephiramine as an example of a cationic surfactant. The ion associate was adsorbed on the inner wall of the vessel by vigorous shaking. After complete removal of the solution in the tube, the ion associate was dissolved with 50% ethanol and measured spectrophotometrically. The proposed method is simple and rapid. The apparent molar absorption coefficient for zephiramine using 20mL of sample and 5mL of eluent was estimated to be 9.01×10⁴Lmol^–1cm^–1 at 415nm. The coefficient of variation for 20.2µg of zephiramine was 5.9% (n=10).     

Improving precision of manual hydrodynamic injection in capillary electrophoresis with contactless conductivity detection

Reproducible injection in capillary electrophoresis has been difficult to achieve with manual injection techniques using simple injection devices, such as gravity injection (siphoning) or hydrodynamic sample splitting. We demonstrate that the injection reproducibility can be improved using very simple means. With hydrodynamic sample splitter, a passive micro-metering valve can be inserted in-line to regulate the sample flow rate through the splitter interface. A significant improvement of both reproducibility and repeatability was achieved. The reproducibility of RSD of the peak areas improved from 25.4% to 4.4%, while the repeatability was below 4.1% when micro-metering valve was used. Additional simple correction that can be used to further improve the variability of injected sample volumes in any hydrodynamic injection mode in CE with conductivity detection was proposed and verified. The measured EOF peak can serve as a simple indicator of the injected volume and can be effectively used for additional correction. By a linear function between the injection volume and the peak area of the EOF, the RSD values of peak areas for both manual gravity injection and hydrodynamic sample splitter were further improved below 2% RSD. The linearity of the calibration curve was also significantly improved. The proposed correction works even with slight differences in matrix composition, as demonstrated on the analysis aqueous soil extract of model mixture of five nerve agent degradation products.