YBCO堆叠高温超导磁体的磁悬浮振动传递特性实验研究

在YBCO堆叠磁体与永磁轨道构成的高温超导磁悬浮系统中,永磁轨道的振动通过电磁作用传递给YBCO堆叠磁体.本文通过实验研究了振动在YBCO堆叠磁体磁悬浮系统中的传递效率与基振加速度幅值和基振频率的关系.研究表明:在YBCO堆叠磁体磁悬浮系统中,YBCO堆叠磁体自由振动频率在9 Hz左右;一定低频条件下,振动的传递效率与基振加速度幅值呈正相关趋势,与基振频率呈负相关趋势.     

Effect of Hyper-Resistivity on Nonlinear Tearing Modes

We analytically investigate nonlinear tearing modes with the anomalous electron viscosity or,as it is normally called,hyper-resistivity.In contrast to the flux average method used by previous work,we employ the standard singular perturbation technique and a quasilinear method to obtain the time evolution equation of tearing modes.The result that the magnetic flux grows with time in a scaling as t~(2/3)demonstrates that nonlinear tearing modes with the hyper-resistivity effect alone have a weaker dependence on time than that of the corresponding resistive case.     

新型单羟基氯代咔咯的合成及其光断裂DNA性质

以五氟苯甲醛和吡咯经缩合反应合成了五氟苯基二吡咯烷烃(1); 1与3-氯-4-羟基苯甲醛经缩合反应合成了一个新的10-位苯环被氯原子取代的单羟基自由咔咯--10-(3-氯-4-羟苯基)-5,15-二(五氟苯基)咔咯(〖STHZ〗2〖STBZ〗),收率12.0%,其结构经UV-Vis, ¹H NMR, ¹⁹F NMR, HR-ESI-MS和X-射线单晶衍射表征。琼脂糖凝胶电泳实验发现：2在光照下能够有效引起超螺旋质粒pBR 322 DNA发生断裂,当浓度为100 μmol·L^-1时,活性最强,断裂百分比为68%。     

Block copolymer morphologies confined by square-shaped particle:Hard and soft confinement

The self-assembly of diblock copolymers confined around one square-shaped particle is studied systematically within two-dimensional self-consistent field theory(SCFT).In this model,we assume that the thin block copolymer film is confined in the vicinity of a square-shaped particle by a homopolymer melt,which is equivalent to the poor solvents.Multiple sequences of square-shaped particle-induced copolymer aggregates with different shapes and self-assembled internal morphologies are predicted as functions of the particle size,the structural portion of the copolymer,and the volume fraction of the copolymer.A rich variety of aggregates are found with complex internal self-assembled morphologies including complex structures of the vesicle,with one or several inverted micelle surrounded by the outer monolayer with the particle confined in the core.These results demonstrate that the assemblies of diblock copolymers formed around the square-shaped particle in poor solvents are of immediate interest to the assembly of copolymer and the morphology of biomembrane in the confined environment,as well as to the transitions of vesicles to micelles.     

5G端到端网络切片进展与挑战分析

随着5G端到端网络切片商用部署的逐步推进,在切片实施过程中遇到一些问题和挑战,因此亟需对其当前的研究进展及挑战进一步分析.从对5G端到端网络切片的系统性论述切入,首先介绍了5G网络切片的架构和功能,之后梳理了目前国内外标准组织对网络切片及其增强技术的研究进展,最后识别并深入分析了端到端网络切片面临的挑战,包括SLA保障...     

K_2S-activated carbons developed from coal and their methane adsorption behaviors

The main purpose of this work is to prepare various activated carbons by K2S activation of coal with size fractions of 60-80 meshes, and investigate the microporosity development and corresponding methane storage capacities. Raw coal is mixed with K2S powder, and then heated at 750 ℃-900 ℃ for 30 min-150 min in N2 atmosphere to produce the adsorbents. The texture and surface morphology are characterized by a N2 adsorption/desorption isotherm at 77 K and scanning electron microscopy （SEM）. The chemical properties of carbons are confirmed by ultimate analysis. The crystal structure and degree of graphitization are tested by X-ray diffraction and Raman spectra. The relationship between sulfur content and the specific surface area of the adsorbents is also determined. K2S activation is helps to bring about better development of pore texture. These adsorbents are microporous materials with textural parameters increasing in a range of specific surface area 72.27 m2/g-657.7 m2/g and micropore volume 0.035 cm3/g-0.334 cm3/g. The ability of activated carbons to adsorb methane is measured at 298 K and at pressures up to 5.0 MPa by a volumetric method. The Langmuir model fits the experimental data well. It is concluded that the high specific surface area and micropore volume of activated carbons do determine methane adsorption capacity. The adsorbents obtained at 800 ℃ for 90 min with K2S/raw coal mass ratios of 1.0 and 1.2 show the highest methane adsorption capacities amounting to 106.98 mg/g and 106.17 mg/g, respectively.     

Synthesis of multi-walled carbon nanotubes using CoMnMgO catalysts through catalytic chemical vapor deposition

The Co Mg O and Co Mn Mg O catalysts are prepared by a co-precipitation method and used as the catalysts for the synthesis of carbon nanotubes（CNTs） through the catalytic chemical vapor deposition（CCVD）. The effects of Mn addition on the carbon yield and structure are investigated. The catalysts are characterized by temperature programmed reduction（TPR） and X-ray diffraction（XRD） techniques, and the synthesized carbon materials are characterized by transmission electron microscopy（TEM） and thermo gravimetric analysis（TG）. TEM measurement indicates that the catalyst Co Mg O enclosed completely in the produced graphite layer results in the deactivation of the catalyst. TG results suggest that the Co Mn Mg O catalyst has a higher selectivity for CNTs than Co Mg O. Meanwhile, different diameters of CNTs are synthesized by Co Mn Mg O catalysts with various amounts of Co content, and the results show that the addition of Mn avoids forming the enclosed catalyst, prevents the formation of amorphous carbon, subsequently promotes the growth of CNTs, and the catalyst with decreased Co content is favorable for the synthesis of CNTs with a narrow diameter distribution.The Co Mn Mg O catalyst with 40% Co content has superior catalytic activity for the growth of carbon nanotubes.     

全景开放式高标清兼容新闻直播演播室系统

甘肃省广播电影电视总台全景开放式高标清兼容新闻直播演播室是四迅道系统,包含新闻直播导控、信号调度收录、新闻直播指挥三大系统.整个系统架构以广播级高清为主,兼容标清节目制作播出,完成每天多档咨询新闻,新闻专题、演播室即时制作和播出.     

基于LabVIEW的步进电机控制系统研究

文中分析了磁阻直线旋转步进电机的工作原理,提出了一种基于LabVIEW的控制方法,利用PC串口进行通信,软件采用LabVIEW进行开发,设计了简单的步进电机控制面板,可以实现步进电机的正反转、加减速控制。     

基于物元模型-AHP的电子战无人机作战效能评估

针对电子战无人机作战效能评估问题,建立了电子战无人机作战效能评估指标体系通用框架,提出了基于物元模型-AHP的评估方法,并建立了数学评估模型,以某次复杂电磁环境下电子战无人机联合进攻演练任务为背景,给出了评估模型的仿真算例,结果表明,该方法在电子战无人机作战效能评估中是可行和有效的。