广义 n-皇后问题

它们分别称为Γ_(?) 的第 i 行 ,第 j 列,第 p 条左对角线与第 q 条右对角线.形象地,第 p 条左对角线是从棋盘左下角数起的第 p 条从左上方到右下方的斜线;而第 q 条右对角线是从棋盘左上角数起的第 q 条与左对角线正交的斜线.对Γ_(?) 的任一子集 X,记     

对“磁力小火车”的原理探究及实验验证

根据磁铁在不均匀磁场中受力公式和洛伦兹力公式推导出磁力小火车现象中,小车的平衡速度表达公式,并通过MATLAB和COMSOL等软件结合实验测量数据得出表达式中相关参数数值,利用MATLAB做出小车平衡速度v与电池电压U_0,v与线圈半径R,v与线圈匝数密度n,v与加入磁铁个数N的理论图像,并通过实验探究v与U_0,v与n,v与N的关系,得到的实验图像与理论图像趋势吻合程度较好.     

纤维素在Ni-W/MCM-41下的催化液化

用水热法合成了MCM-41介孔分子筛,通过浸渍法合成含Ni和W的负载型催化剂,并用X射线粉末衍射(XRD)和紫外漫反射(UV-Vis/DRS)等进行表征.以天然纤维素为原料,考察了反应温度、催化剂用量、反应时间、液固比对原料残渣率的影响.实验结果表明,在温度250 ℃,催化剂0.05 g,反应时间2 h,液固比60:1的条件下,原料的残渣率为14.01% .     

Local-global double algebras for slow H{infty} adaptation; the case of l2 disturbances

In this paper, a common algebraic framework is described forthe frozen-time analysis of stability and H optimization inslowly time-varying systems, based on the notion of a normedalgebra on which local and global products are defined. Relationsbetween local stability, local (near) optimality. local coprimefactorization, and global versions of these properties are sought.The framework is valid for time-domain disturbances in l² (Z)^R. The first part of the paper elaborates the double-algebra conceptfor Volterra operators which approximately commute with theshift. The main algebraic properties and norm inequalities aresummarized. Local conditions for global inveribility are obtained.Classical frozen-time stability conditions are incorporatedin relations between local and global spectra. The paper continuesby establishing an explicit formula linking global and localsensitivity for systems with stable plants, where local sensitivityis a Lipschitz continuous function of data. Frequency-domainestimates of time-domain sensitivity norms. which become accurateas rates of time-variation approach zero, are obtained. Notionsof adaptive versus nonadaptive (robust) control are introduced.It is shown that adaptive control can achieve better sensitivitythan optimal nonadaptive control. It is demonstrated by an examplethat, in general, H-optimal interpolants do not depend Lipschitz-continuouslyon data. However, -suboptimal interpolants of the AAK central(maximal entropy) type are shown to satisfy a tractable Lipschitzcondition.     

电子光学教学实验的开发

介绍利用单踪示波器的阴极射线管,结合模拟软件,开展电子光学实验教学的教学内容设计和教学实践情况.电子光学实验教学的开展有利于学生掌握相关知识和研究方法,受到学生欢迎.     

运输密度和时间对拟目乌贼受精卵孵化的影响

为探究拟目乌贼受精卵长途运输的最佳条件,通过单因子试验研究了受精卵运输密度及运输时间对拟目乌贼受精卵孵化的影响.结果表明：运输密度对孵化率、幼体成活率、初孵幼体体重及卵黄完全吸收率均有显著影响(P＜0.05),各项指标均随着密度的增加而降低;运输时间对受精卵孵化也有显著影响(P＜0.05),各项指标也随着时间的增加而降低.因此建议运输密度为100~300 ind·L-1,运输时间为36 h以内.     

自制简易吸尘器

利用身边易得的材料,如可乐瓶、铜线、单摆球等,根据静电原理自制了简易吸尘器.介绍了该装置的制作和使用方法.     

关于Diophantine方程(n+1)+(n+2)y=nz

设n是正整数.本文证明了:方程(n+1)+(n+2)y=nz仅当n=3时有正整数解(y,z)=(1,2).     

室温下金刚石薄膜上沉积立方氮化硼薄膜的研究

采用射频磁控溅射技术分别在纳米与微米金刚石薄膜上制备立方氮化硼(c- BN)薄膜.金刚石薄膜由拉曼光谱(Raman)及原子力显微镜(AFM)进行表征.采用傅立叶变换红外光谱(FTIR)研究了不同沉积温度对c- BN薄膜生长的影响,结果表明在金刚石薄膜上生长c- BN不存在温度阈值,室温下生长的c- BN含量可达70;以上.当沉积温度由室温向上升高时,对于纳米金刚石薄膜衬底上生长的BN薄膜而言,其中的立方相含量反而逐渐降低.此外,随着沉积温度的降低,c- BN对应的峰位向低波数方向偏移的现象表明低温下生长的c- BN薄膜内应力较小.文中探讨了产生此现象的原因.