Controlling a complex dynamical network to attain an inhomogeneous equilibrium

Many networks are made up of a few groups, with nodes in the same group having the same kind of function. In this work, the problem of controlling a complex dynamical network to attain an inhomogeneous equilibrium point is investigated, which means that nodes in the same group achieve the same equilibrium point as an isolated node, while different groups correspond to different equilibrium points. An open-loop constant control approach is first proposed to obtain the inhomogeneous equilibrium point of the network. Then, the feedback pinning control approach is applied to make the inhomogeneous equilibrium point asymptotically stable.     

空间对接机构差动式机电缓冲阻尼系统机构传动原理分析

对空间对接机构中差动式机电缓冲阻尼系统的基本构成、系统主要部件及其在各种工作模式下的机构传动原理进行了较为深入的探讨，基本上搞清楚了差动式机构的结构原理，这是研究对接机构系统必须突破的一项关键技术。     

Determination of energy transfer and upconversion constants for Yb~(3+)/Er~(3+) codoped phosphate glass

<正>The energy transfer and cooperation upconversion processes are investigated in Yb~(3+)/Er~(3+) codoped phosphate glass.Based on the measured curves of output power versus incident power,the laser and spectroscopic parameters of the glass are fitted and analyzed.We focus on the resonant energy transfer constant k from Yb~(3+) to Er~(3+) as well as the cooperation upconversion coefficient C_(up) from ~4I_(13/2) of Er~(3+).The fitted k and C_(up) can give almost the same results for different thicknesses of glass disk with the same doping concentrations.The determination of these parameters is helpful for the development of Yb~(3+)/Er~(3+) codoped laser glass.     

Chemical Synthesis of Several 2'-O-, 3'-O-Glycosylated Diosgenyl β-D-Glucopyranosides

ABSTRACT

Six 2'-O-, 3'-O-glycosylated diosgenyl β-D-glucopyranosides (4-9), which have a typical structural pattern of diosgenyl saponins, were synthesized; their synthetic routes are discussed.     

一组一点外推的数值积分公式的提出与验证

通过利用拉格朗日多项式对等间距的离散采样数据进行函数逼近,就相等间距外推一点进行积分,得到了具有一定未来预测能力的一组一点外推的数值积分公式.计算机数值实验的结果表明了公式的有效性,即应用公式预测的积分结果可以达到一个较高的精度.     

新型金属团簇化合物的光限幅特性研究

应用倍频 Nd:YAG脉冲激光 ,在波长为 5 32 nm、脉冲宽度为 8ns的条件下 ,研究了金属团簇化合物WOS3Cu3I(2 - Me Py) 3的光限幅特性。其光限福特性优于富勒烯。Z- Scan研究结果表明 :该团簇具有自聚焦特性 ,其光限幅起源于激发态吸收     

When underwater degraded images meet logical stochastic resonance

Owing to light attenuation and high background noise, underwater images are significantly degraded, which hiders the development of underwater exploration. However, noise itself can be used to counter noise. In this paper, we apply logical stochastic resonance (LSR) to help detect weak objects from low-quality underwater images. On the basis of analysis of the physical character of underwater images, three models, namely basic dynamical system driven by Gaussian noise, basic dynamical system driven by Ornstein–Uhlenbeck (OU) noise, and dynamical system with extra delay loop, are chosen to study the performance of LSR-based object detection. The main workflow of LSR-based object detection is introduced. To analyze the performance of LSR, we perform explicit experiments and systematically discuss the interplay of additional noise with the system parameters. LSR is proven to be helpful in detecting weak objects from low-quality underwater images. Both OU noise and extra delay loop will help the whole system to maintain stability in a higher noisy background.     

表面水热碳层对磁性NiFe2O4八面体光催化活性的影响

采用葡萄糖水热碳化法合成了一系列碳层包覆的NiFe₂O₄核壳八面体(NiFe₂O₄@C). 通过调控葡萄糖的含量可以有效控制NiFe₂O₄表面包覆的碳层厚度. 利用X射线衍射(XRD)、 拉曼光谱(Roman)、 X射线光电子能谱(XPS)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)和紫外-可见漫反射光谱(UV-Vis DRS)等对NiFe₂O₄@C的组成、 结构、 形貌和光学性能进行了表征. 考察了表面水热碳层对NiFe₂O₄光催化降解亚甲基蓝(MB)性能的影响. 结果表明, NiFe₂O₄的光催化活性很大程度上依赖于在其表面包覆的碳层厚度, 碳层厚度为5.5 nm的NiFe₂O₄@C-3展现了最佳的光催化活性. 荧光光谱(PL)、 瞬态光电流和电化学阻抗谱(EIS)表征结果证明, NiFe₂O₄@C的光催化性能的提升归因于在NiFe₂O₄核和碳壳之间形成了异质结, 有效地促进了光生载流子的传输和分离效率. NiFe₂O₄@C复合材料展现了较好的稳定性和可回收性, 在污水处理方面有很大的应用潜力.     

Simulation of loss of uranium ions due to charge changing processes in the CSRm ring

Significant beam loss caused by the charge exchange processes and ion impact-induced outgassing may restrict the maximum number of accelerated heavy ions during the high intensity operation of an accelerator. In order to control beam loss due to charge exchange processes and confine the generated desorption gas, tracking of the beam loss distribution and installation of absorber blocks with low-desorption rate material at appropriate locations in the main Cooler Storage Ring (CSRm) at the Institute of Modern Physics, Lanzhou, will be performed. The loss simulation of uranium ions with electron-loss is presented in this report and the conclusion is that most charge changed particles are lost in the second dipole of the super-period structure. The calculation of the collimation efficiency of the CSRm ring will be continued in the future.     

高效率内腔式2 μm简并光学参量振荡器

报道了一种高效率的2 μm光学参量振荡器. 利用1.064 μm声光调Q Nd:YVO₄激光器抽运基于氧化镁掺杂周期性极化铌酸锂的内腔式光学参量振荡器, 在简并状态实现了稳定高效的2 μm激光输出. 当808 nm激光二极管抽运功率为20 W, Q开关工作频率为15 kHz时, 产生了平均功率为3.5 W、脉冲宽度为1.4 ns的2 μm激光, 光-光转换效率为17.5%, 斜效率为25%. 据我们所知, 该转换效率在2 μm波段内腔式光学参量振荡器中是最高的.