P-循环矩阵和块AOR方法(英)

本文首先导出P-循环矩阵的块Jacobi迭代矩阵和相应的块AOR迭代矩阵的特征值间的关系式．然后，我们确定块AOR方法用于最小二乘问题时的收敛和发散区域．     

Novel hybrid mitigation strategy for improving the resiliency of hierarchical networks subjected to attacks

This paper studies the resiliency of hierarchical networks when subjected to random errors, static attacks, and cascade attacks. The performance is compared with existing Erdös–Rényi (ER) random networks and Barabasi and Albert (BA) scale-free networks using global efficiency as the common performance metric. The results show that critical infrastructures modeled as hierarchical networks are intrinsically efficient and are resilient to random errors, however they are more vulnerable to targeted attacks than scale-free networks. Based on the response dynamics to different attack models, we propose a novel hybrid mitigation strategy that combines discrete levels of critical node reinforcement with additional edge augmentation. The proposed modified topology takes advantage of the high initial efficiency of the hierarchical network while also making it resilient to attacks. Experimental results show that when the level of damage inflicted on a critical node is low, the node reinforcement strategy is more effective, and as the level of damage increases, the additional edge augmentation is highly effective in maintaining the overall network resiliency.     

城市生活垃圾混合填埋模拟实验

本文采用城市生活垃圾的填埋降解模拟装置,对不同垃圾成份在垃圾降解过程的垃圾渗滤液水质指标变化、重金属含量变化、垃圾减量化、沉降高度和pH值的变化进行研究.实验结果表明:在填埋生活垃圾中添加医疗垃圾焚烧底灰,可加快填埋垃圾的降解使垃圾的Cu、Zn、Pb、和(NH3-N)含量都有不同程度的下降,COD、C I-含量和(NH3-N)分别降为67%、45%和69%.     

NVC／BA共聚物的合成及其掺杂C60体系光电导性能研究

详细研究了Ｎ－乙烯基咔唑（ＮＶＣ）与丙类酸丁酯（ＢＡ）的共聚反应。用Ｆｉｎｅｍａｎ－Ｒｏｓｓ法测定了两种单体的竞聚率，发现两单体的竞聚率比较接近，可以进行较好的共聚合反应。通过ＴＥＭ观察，发现加入共聚单体ＢＡ可以大大改善聚乙烯基咔唑（ＰＶＫ）的成膜性能。     

Novel sorption-based methodologies for static microextraction analysis: A review on SBSE and related techniques

Stir bar sorptive extraction (SBSE) became a well-established analytical technique in the last years, for which hundreds of applications in almost all types of scientific fields can be found in the literature. In spite of the great enrichment capacity and outstanding performance to operate at the ultra-trace level, this remarkable static sorption-based method is already not quite effective for some complex systems, in particular to monitor the large group of polar organic compounds. This review aims to cover the state-of-the-art in SBSE, as well as supplying a discussion of the analytical potential of the novel adsorptive microextraction techniques, as complementary enrichment approaches, by explaining the main principles and providing technical know-how for the beginners.     

Acrylic coatings exhibiting improved hardness, solvent resistance and glossiness by using silica nano-composites

To prepare nano-composite emulsion acrylic resins with improved surface hardness and solvent resistance, nano-silica particles were treated with surfactants. The monomers of methyl methacrylate/butylacrylate were co-polymerized on the surface of dispersed silica particles. Several emulsions with different silica contents and copolymer mole fractions were prepared. Finally the emulsions were modified to water-based acrylic coatings and improved properties such as surface hardness, solvent resistance and glossiness were determined. The study of coatings was directed to find the improved resin by optimum surface properties. Size distribution and morphology of latexes were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. The glass transition temperature of nano-composites was measured and discussed its relation with silica contents, monomer mole fractions and improved properties of coatings. The optimum pendulum hardness of coatings was on 0.46 methyl methacrylate mole fraction and 120 g silica content. An increase in pendulum hardness of nano-composites with the addition of modified silica was observed. DLS and TEM studies indicate that silica particles were dispersed homogenously through the polymer matrix.     

甜荞愈伤组织分化研究

研究了龙山荞、浦江荞、美国荞和牡丹荞四种甜荞子叶和下胚轴的愈伤组织形成与分化的影响因子.结果表明：17.8μmol/L～26.6μmol/L（4.0 mg/L～6.0 mg/L）的BA与0.9μmol/L（0.2 mg/L）的2,4-D配合使用可有效促进甜荞愈伤组织中芽的分化和芽的生长;高浓度的蔗糖（4.5%～6.0%）促进甜荞愈伤组织根的分化和愈伤组织的生长;在培养基中附加活性炭抑制甜荞愈伤组织分化根.     

高粱稻成熟胚对2,4-D和6-BA的生理反应

在2，4-D0～10，BA0～5（mg／L）交叉配比的MS培养基上培养高粱稻超丰早一号的外植体--成熟种子，发现2，4-D对成熟胚的生根率、根产量、出愈率、愈伤组织生长速率、愈伤组织性质、种子苗发生频率都起主要作用．BA对根形态、愈伤组织胚性有较明显的作用；如果BA浓度较高，则能较明显地抵消2，4-D的作用，0．5mg／L的2，4-D同BA结合产生的愈伤组织生长速率快，胚性良好．在2，4-D0．5～3mg／L，并含有BA的组合中，发生的种子苗出现一些形态上的变异．     

活性正离子聚合与原子转移自由基聚合转换合成聚β-蒎烯接枝共聚物

通过活性正离子聚合与原子转移自由基聚合(ATRP)转换合成了β-蒎烯与甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、苯乙烯(St)的新型接枝共聚物.首先以α-氯代乙苯/TiCl4/Ti(OiPr)4/nBu4NCl体系引发β-蒎烯活性正离子聚合,合成预定分子量大小和窄分子量分布的聚β-蒎烯,然后经N-溴代琥珀酰亚胺(NBS)定量溴化,得到溴化聚β-蒎烯大分子引发剂(Br/β-蒎烯链节摩尔比为0.5).然后将该大分子引发剂与溴化亚铜(CuBr)/2,2′-联吡啶(bpy)复合,引发MMA、BA、St进行ATRP接枝聚合.接枝反应显示一级动力学特征,且产物的分子量及分子量分布可控,表明上述ATRP接枝聚合反应具有可控聚合特征.接枝产物的结构经1H-NMR分析得到进一步证实.     

Ultrasound-assisted synthesis of poly(MMA–co–BA)/ZnO nanocomposites with enhanced physical properties

The present study reports synthesis and characterization of poly(MMA–co–BA)/ZnO nanocomposites using ultrasound-assisted in-situ emulsion polymerization. Methyl methacrylate (MMA) was copolymerized with butyl acrylate (BA), for enhanced ductility of copolymer matrix, in presence of nanoscale ZnO particles. Ultrasound generated strong micro-turbulence in reaction mixture, which resulted in higher encapsulation and uniform dispersion of ZnO (in native form – without surface modification) in polymer matrix, as compared to mechanical stirring. The nanocomposites were characterized for physical properties and structural morphology using standard techniques such as XRD, FTIR, particle size analysis, UV–Visible spectroscopy, electrical conductivity, TGA, DSC, FE-SEM and TEM. Copolymerization of MMA and BA (in presence of ZnO) followed second order kinetics. Thermal stability (T_10% = 324.9 °C) and glass transition temperature (T_g = 67.8 °C) of poly(MMA-co-BA)/ZnO nanocomposites showed significant enhancement (35.1 °C for 1 wt% ZnO and 15.7 °C for 4 wt% ZnO, respectively), as compared to pristine poly(MMA–co–BA). poly(MMA–co–BA)/ZnO (5 wt%) nanocomposites possessed the highest electrical conductivity of 0.192 μS/cm and peak UV absorptivity of 0.55 at 372 nm. Solution rheological study of nanocomposites revealed enhancement in viscosity with increasing ZnO loading. Maximum viscosity of 0.01 Pa-s was obtained for 5 wt% ZnO loading.