Role of the zonal flow in multi-scale multi-mode turbulence with small-scale shear flow in tokamak plasmas

The structural characteristics of zonal flows and their roles in the nonlinear interaction of multi-scale multi-mode turbulence are investigated numerically via a self-consistent Landau-fluid model. The multi-mode turbulence here is composed of a shorter wavelength electromagnetic (EM) ion temperature gradient (ITG) mode and a Kelvin-Helmholtz (KH) instability with long wavelengths excited by externally imposed small-scale shear flows. For strong shear flow, a prominent periodic intermittency of fluctuation intensity except for dominant ITG component is revealed in turbulence evolution, which onset time depends on the ion temperature gradient and the shear flow amplitudes corresponding to different KH instabilities. It is identified that the intermittency phenomenon results from the zonal flow dynamics, which is mainly generated by the KH mode and back-reacts on it. It is demonstrated that the odd symmetric components of zonal flow (same symmetry as the external flow) make the radial parity of the KH mode alteration through adjusting the drift velocities at two sides of the resonant surface so that the KH mode becomes bursty first. Afterwards, the ITG intermittency follows due to nonlinear mode coupling. Parametric dependences of the features of the intermittency are elaborated. Finally, associated turbulent heat transport is evaluated.     

非晶氧化锆水合物红外研究

用红外吸收光谱（ＩＲ）结合Ｘ射线衍射（ＸＲＤ）、差热（ＤＴＡ）和理分析（ＴＧ）详细研究了氧化锆前驱物（溶胶凝胶法制得的非晶态氧化锆水合物）的结构，实验结果表明在非晶态氧化锆水合物中有三种不同的近程结构，它表现为不同条件下制得的非晶氧化锆水合物的红外吸收谱在１７００～１２００ｃｍ＾－１水和羟基的弯曲振动吸收区出现１６３３、１５５１、１４００和１３４０ｃｍ＾－１四个不同的羟基吸收峰，这表明样品中有三种     

入射角度对远红外与激光兼容伪装光子晶体特性的影响研究

利用薄膜光学理论中的特征矩阵法计算了所设计的光子晶体薄膜的反射光谱,利用镀膜法制备了光子晶体薄膜.同时进行了样品光谱曲线的测试,并对其在远红外波段的发射率进行了测试.测试结果表明,制备的光子晶体在10.6μm激光波长处的反射率较低,并且在除缺陷处的远红外波段的反射率较高,因此,可以实现远红外与10.6 μm激光兼容.但当入射角度的增加时,激光波长处的反射率有所上升,并向短波方向偏移;在除激光波长处的远红外波段的反射率也降低较多.因此,入射角度的增加对光子晶体兼容效果的影响逐渐增大.     

基于无杆牵引车的舰载机路径跟踪控制

针对航母机库空间狭小、障碍物多等因素导致舰载机转运难度大的问题,以无杆牵引车和舰载机组成的铰接系统为研究对象,研究了舰载机在机库甲板调运作业的路径自动跟踪问题,建立了基于无杆牵引车的舰载机转运模型,将舰载机期望路径近似为直线和圆弧的组合,基于反馈线性化和时间-状态形式设计各路段的跟踪控制律,仿真结果表明,所设计的控制律和各控制律间的切换策略可实现舰载机沿组合路径的跟踪;基于自动跟踪的调运,可放宽对牵引车司机牵引技术的要求,确保调运作业时间准确、可控;该研究为后续自动跟踪的实现打下基础。     

Effect of Thermionic Emission on Dust-Acoustic Solitons in a Dust-Electron Plasma

The effects of thermionic emission on dust-acoustic solitons with a very small but finite amplitude in a dustelectron plasma are studied using the reductive perturbation technique. The self-consistent variation of dust charge is taken into account. It is shown that the thermionic emission could significantly increase the dust positive charge. The dependences of the phase velocity, amplitude, and width of such solitons on the dust temperature and the dust work function of dust material are plotted and discussed.     

气相色谱-电子轰击电离/正化学电离质谱法测定白菜和苹果中3种有机锡类农药残留

分别采用电子轰击电离(EI)源和正化学电离(PCI)源两种离子源技术建立了气相色谱-质谱(GC-MS)同时测定白菜和苹果中苯丁锡、三苯锡和三环锡含量的方法,并对这两种方法进行了比较。样品经氢溴酸消解、丙酮-正己烷(1∶2,v/v)提取,四乙基硼化钠衍生后用Florisil固相萃取柱净化,分别在EI源和PCI源下以选择离子监测模式进行测定。结果表明,方法的检出限(S/N=3)分别为0.01~0.05 mg/kg(EI源)和0.01~0.02 mg/kg(PCI源),定量限(S/N=10)分别为0.03~0.16 mg/kg(EI源)和0.02~0.06 mg/kg(PCI源)。三苯锡、三环锡和苯丁锡分别在各自的线性范围内线性关系良好,相关系数(r~2)≥0.997。在50、100、200μg/kg 3个添加水平下,采用GC-EI/MS和GC-PCI/MS时,阴性样品中3种有机锡的平均回收率分别为59.24%~97.36%(苹果)、50.54%~94.54%(白菜)和65.38%~95.86%(苹果)、62.56%~90.44%(白菜),相对标准偏差(RSD)均不超过6.9%(n=6)。该方法简单、灵敏,PCI源的选择性优于EI源,两种方法可以相互结合提高检测结果的可靠性。     

固态组合化学及其在材料科学中的应用

概述了固态组合化学的概念及其在新材料开发中的应用 ,着重阐述了材料化合物薄膜库的组合制备方法和筛选技术的特点 ,简述了固态组合化学技术在超导、巨磁阻、磷光、催化剂、沸石等新材料开发中的应用以及固态组合化学现有技术中的困难和今后的发展方向     

The second Hopf bifurcation in lid-driven square cavity

To date, there are very few studies on the second Hopf bifurcation in a driven square cavity, although there are intensive investigations focused on the first Hopf bifurcation in literature, due to the difficulties of theoretical analyses and numerical simulations. In this paper, we study the characteristics of the second Hopf bifurcation in a driven square cavity by applying a consistent fourth-order compact finite difference scheme recently developed by us. We numerically identify the critical Reynolds number of the second Hopf bifurcation located in the interval of(11093.75, 11094.3604) by bisection. In addition, we find that there are two dominant frequencies in its spectral diagram when the flow is in the status of the second Hopf bifurcation, while only one dominant frequency is identified if the flow is in the first Hopf bifurcation via the Fourier analysis. More interestingly, the flow phase portrait of velocity components is found to make transition from a regular elliptical closed form for the first Hopf bifurcation to a non-elliptical closed form with self-intersection for the second Hopf bifurcation. Such characteristics disclose flow in a quasi-periodic state when the second Hopf bifurcation occurs.     

基于Schiff碱及咪唑类配体的镍（Ⅱ）配合物的合成、结构及其抑菌活性研究

本文以三齿席夫碱配体H₂L{1-苯基-3-[（2-羟基苯）亚胺]-1-丁酮}和单齿N-杂环[咪唑（Himdz）,2-甲基咪唑（Mimdz）]与Ni（OAc）₂·4H₂O进行配位反应,得到2个配合物[Ni（L）（Himdz）]（1）,[Ni（L）（Mimdz）]（2）。并用元素分析,FTIR和X-射线单晶衍射进行了表征。在固体状态,配合物1和2都属于单斜晶系,P2₁/c空间群,分子间通过C-H…π相互作用形成二聚体,二聚体中的每个分子通过N-H…O氢键向空间扩展成一维锯齿链状结构。初步研究了配体和配合物的体外抑菌活性,结果表明,配合物1和2具有一定的抑菌活性。