双会议服务器选址问题研究

中位选址问题一直是管理学科的研究热点,本文考虑平面点集选址问题中的双会议服务器选址问题,该问题可以看成是2中位问题的衍生问题。令P为平面上包含n个点的点集,双会议服务器选址问题即为寻找由该点集构成的一棵二星树,使得这棵树上所有叶子之间的距离和最小。本文给出求解该问题的关键几何结构和最优解算法设计,并证明所给算法时间复杂性为O(n³logn)。     

Low-energy D^＊＋D1^0 scattering and the nature of resonance-like structure Z^＋（4430）

Low-energy scattering of D ^＊＋ and D1^0 meson is studied using quenched lattice QCD with improved lattice actions on anisotropic lattices.The threshold scattering parameters,namely the scattering length a 0 and the effective range r 0,for the s-wave scattering in J P = 0 - channel are extracted： a 0 = 2.52（47） fm and r 0 = 0.7（1） fm.It is argued that,albeit the interaction between the two charmed mesons being attractive,it is unlikely that they can form a shallow bound state in this channel.Our calculation provides some useful information on the nature of the newly discovered resonance-like structure Z ＋ （4430） by the Belle Collaboration.     

抗体与多酶负载纳米金的合成表征及纸上化学发光性能研究——介绍一个仪器分析综合实验

对抗体及多酶负载纳米金的合成、表征及纸上化学发光性能进行了研究,实验结合了目前的研究成果,内容涵盖了材料化学、仪器分析、无机合成、胶体化学等方面,涉及材料和生物分析等领域。本实验还可进行后续癌症标志物免疫分析的拓展实验研究,可作为8学时的仪器分析综合实验,给大学三年级的学生开设。     

明胶-聚丙烯酸纳米微球的一维自组装制备纳米棒

明胶-聚丙烯酸纳米微球可在4℃下自组装形成纳米棒,所形成的纳米棒结构规整并具有与纳米微球相同的直径.通过观察纳米棒形成的中间状态,发现该纳米棒由明胶-聚丙烯酸纳米微球一维排列而成.由于只有在较低温度下纳米微球才能形成棒状结构,并且圆二色性光谱数据证明明胶-聚丙烯酸纳米微球表面的明胶分子具有在低温下复性成为三螺旋构象的能力,因此可以推断明胶-聚丙烯酸纳米棒是由纳米微球表面的明胶分子通过复性为三螺旋结构所产生的氢键以及静电等力的作用一维自组装而形成的.     

聚乙二醇-金纳米棒介导的近红外光热抑菌作用

种子生长法合成纵向表面等离子体共振吸收峰为785 nm的金纳米棒,并对其表面进行聚乙二醇(PEG)修饰,研究了表面修饰PEG的金纳米棒(polyethylene glycol modified gold nanorods,PEG-GNR)的光热转化效应,并测试了其细胞毒性.以革兰氏阳性菌金黄色葡萄球菌、蜡状芽孢杆菌,革兰氏阴性菌大肠埃希氏菌及铜绿假单胞菌为细菌模型,详细研究了PEG-GNR在808 nm波长近红外激光照射下金纳米棒浓度和照射功率对抑菌效果的影响.结果表明,PEG-GNR对革兰氏阳性菌和革兰氏阴性菌在近红外照射下均有较好的抑菌效果,并且抑菌效果与金纳米棒的浓度和照射功率有着密切的关系;结合荧光显微镜和透射电子显微镜对细菌坏死状况的观察,初步证实细菌对PEG-GNR有效吸收是近红外光热杀菌的关键因素.     

Ag/Bi2WO6复合材料的制备及光催化性能

采用一步水热合成法制得花球状Bi_2WO_6和Ag/Bi_2WO_6光催化剂,借助X射线衍射(XRD)、场发射扫描电子显微镜(FES-EM)、透射电子显微镜(TEM)、X射线光电子能谱分析(XPS)、紫外-可见分光光度法(UV-Vis)等手段对样品进行结构性能表征。模拟日光的条件下,以甲基橙(MO)为降解物,对Bi_2WO_6和Ag/Bi_2WO_6的催化活性和机理进行研究。结果表明,相对Bi_2WO_6,相同条件下Ag/Bi_2WO_6对MO具有更佳的降解效果,当Ag掺杂量为1%(n/n)时,其降解率(180 min)可达到91.4%,同时一次回收样降解率也达到81%。此外,也对Ag/Bi_2WO_6复合材料的降解机理做了初步探究。     

Effect of Mo doping on phase change performance of Sb2Te3

Mo, as a dopant, is doped into SbTe to improve its thermal stability. It is shown in this paper that the Mo-doped Sb₂Te₃ (Mo_0.26Sb₂Te₃, MST) material possesses phase change memory (PCM) applications. MST has better thermal stability than Sb₂Te₃(ST) and will crystallize only when the annealing temperature is higher than 250 ℃. With the good thermal stability, MST-based PCM cells have a fast crystallization time of 6 ns. Furthermore, endurance up to 4×10⁵ cycles with a resistance ratio of more than one order of magnitude makes MST a promising candidate for PCM applications.     

Phase transition in finite density and temperature lattice QCD

We investigate the behavior of the chiral condensate in lattice QCD at finite temperature and finite chemical potential. The study was done using two flavors of light quarks and with a series of β and ma at the lattice size 24×12²×6. The calculation was done in the Taylor expansion formalism. We are able to calculate the first and second order derivatives of <ψψ> in both isoscalar and isovector channels. With the first derivatives being small, we find that the second derivatives are sizable close to the phase transition and that the magnitude of ψψ decreases under the influence of finite chemical potential in both channels.     

多子直方图均衡微光图像增强及FPGA实现

针对微光图像对比度低,目标难以识别的问题,对微光图像增强算法进行了研究。提出了一种多子直方图均衡增强算法,该算法首先将直方图按面积平均分割成4个子直方图,利用平均像素数量作为阈值切割直方图降低过度增强现象,然后加入尺度因子对动态范围进行调整,最后分别对子直方图均衡得到增强效果。此算法用Verilog语言在现场可编程门阵列（FPGA）上具体实现,并给出了主观和客观的评价,改进算法能产生更清晰的图像,在硬件平台上也能实时显示增强效果,一帧图像处理时延约为0.45 ms。实验结果表明,改进算法不会产生饱和、噪声放大的现象,图像细节保持较好,满足视频图像处理实时性要求,得到了具有较好视觉效果的增强图像。     

Electromagnetic Response of High-Frequency Gravitational Waves by Coupling Open Resonant Cavity

We present a new detecting scheme of high-frequency gravitational waves （HFGWs） in the GHz band, the scheme consists of a high-quality-factor open microwave cavity, a static magnetic field passing through the cavity and an electromagnetic （EM） normal mode stored in the cavity. It is found that under the resonant condition first- and second-order perturbation EM effects have almost the same detecting sensitivity to the HFGWs in the GHz band （h ～10^-26, v～5GHz）, but the former contains more information from the HFGWs. We also provide a very brief review for possible improving way of the sensitivity. This scheme would be highly complementary to other schemes of detecting the HFGWs.