植物间的相关相克作用

本文对植物间的相关相克的概念,存在的普遍性,在生态、农业、林业、园艺中的作用以及相关相克化学物质的化学性质和作用机理做了较为全面的概括评述。对当前和今后的研究重点和方向提出了建议性意见,并对植物间相关相克研究的应用前景给予充分的估价.     

基于OPNET的机群数据链混合TDMA协议仿真

针对当前数据链的时隙分配问题,提出并实现了一种基于灰色关联分析法的混合时隙分配协议。通过灰色关联分析法对吞吐量、时延和当前报文缓冲区的负载程度做聚合,得到各节点综合得分,根据综合得分对时隙进行动态分配,同时采用固定时隙分配的方式保证网络中的节点最少有一个时隙可用。仿真结果表明：与固定TDMA(time division multiple access)协议和P-TDMA(priorityTDMA)协议相比,该协议在减少竞争冲突的同时,也保证了较低的时延、相对较高的吞吐量和高时隙利用率。     

纳米固体超强酸SO4^2-/TiO2的制备及其催化活性

以廉价的无机盐TiCl4为原料,采用溶胶-凝胶法结合超临界流体干燥技术制备出纳米TiO2粉末,经硫酸溶液浸泡、活化后制成纳米固体超强酸SO4^2-/TiO2.着重探讨了纳米固体超强酸的制备条件,并将其用于乙酸正丁酯的合成反应以考察其催化活性.结果表明：该法制备的纳米固体超强酸SO4^2-/TiO2具有很强的催化活性,且制备成本低,反应时间短,酯化率高.     

放顶煤开采煤体裂隙演化规律实验研究

运用ＭＳＳ－３００型真三轴压力试验机对忻州窑矿放顶煤工作面的大煤样试件进行了压裂实验研究,运用分形理论探讨了煤样的裂隙演化规律,为研究放顶煤工作面顶煤的破裂演化规律及采用人工弱化顶煤措施提供了必要的理论依据。探讨了放顶煤采场有关数值计算中力学参数合理选取的新途径。     

试论现代意识教育

从学生的民主和法制意识、人才和科技教育意识以及人口和资源意识出发,论述了教师如何在思想政治课教学中向学生进行现代意识教育。     

无向双环网络G(N;±r,±s)直径求解方法

提出新的无向双环网络G(N;±r,±s)的直径求解法———分步法;并得到一种新的直观图———螺旋环,研究了螺旋环的性质;给出了无向双环网络的直径d(N;±r,±s)的显式公式;给出了N,s都固定的直径算法;在N固定,且2≤r相似文献   

准一维基于分子亚铁磁体自旋系统磁化率性质研究

基于交替自旋Ising—Hamiltonian模型,用量子转移矩阵方法,研究了不同外场条件下准一维基于有机分子亚铁磁体磁化率的结构序参量．对磁化率一的研究表明：双自由基和单自由基的交替有机自旋链的亚铁磁自旋排列等效于有效自旋S=1／2的铁磁相互作用链,双自由基有机高分子对具有单一成分的有机基于分子亚磁体具有绝对优势．量子Monte Carlo方法和精确对角化方法的计算结果两者相符,且与某些实验结果定性相符．     

Design and analysis of high-throughput screening experiments

Saturated row-column designs are studied to eliminate positional effects in primary highthroughput screening experiments. Compared to designs currently used in practice, all compounds in the designs considered are comparable within each microplate in spite of the existence of row and column effects. The designs considered in this paper also have the maximum number of compounds arranged in each microplate. Two statistical methods are used to choose leading compounds in the designs considered. These two methods take full advantages of effect sparsity in primary screening. Simulation studies are carried out to compare the two statistical methods with two ad hoc methods in selecting active compounds. A method that maintains balanced false positives and false negatives is recommended.     

Comprehensive multivariate grey incidence degree based on principal component analysis

To overcome the too fine-grained granularity problem of multivariate grey incidence analysis and to explore the comprehensive incidence analysis model, three multivariate grey incidences degree models based on principal component analysis （PCA） are proposed. Firstly, the PCA method is introduced to extract the feature sequences of a behavioral matrix. Then, the grey incidence analysis between two behavioral matrices is transformed into the similarity and nearness measure between their feature sequences. Based on the classic grey incidence analysis theory, absolute and relative incidence degree models for feature sequences are constructed, and a comprehensive grey incidence model is proposed. Furthermore, the properties of models are researched. It proves that the proposed models satisfy the properties of translation invariance, multiple transformation invariance, and axioms of the grey incidence analysis, respectively. Finally, a case is studied. The results illustrate that the model is effective than other multivariate grey incidence analysis models.