微波调控石墨烯-碳纳米管协同增强聚氨酯损伤自修复研究

首先采用溶液共混法制备出石墨烯-碳纳米管(G-CNT)/聚氨酯(TPU)复合材料,然后通过拉伸实验及扫描电子显微镜(SEM)表征来考察该材料的拉伸强度和微波自修复特性,并从力学及材料与微波之间的相互作用等角度对其拉伸强度增强和微波修复机理进行研究.结果表明:在拉伸强度方面,与单一的石墨烯或CNT增强TPU相比,G-CNT之间形成的协同效应使TPU拉伸强度得到进一步提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU抗拉强度较纯TPU提高了67%,较G/TPU提高了18%,较CNT/TPU提高了25%;在材料裂纹的微波修复方面,石墨烯和CNT之间的协同效应使TPU材料自修复效果得到有效提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU修复效果达到最高值117%.     

台阶爆破破碎度的分布规律

本文采用摄影方法在海州露天煤矿对台阶爆破破碎块度进行了测量。根据现场试验所获得的数据,通过多元曲线拟合处理,给出了二种岩石爆破破碎块度的分布规律。所得结论对控制和提高爆破破碎质量具有重要意义。     

无催化剂条件下微波辐射一步法合成2-氨基-4-芳基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃-3-腈

以芳醛、丙二腈、1,3-环己二酮为原料在无催化剂条件下,分别用微波辐射和传统加热法合成了一系列2-氨基-4-芳基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃-3-腈(4a～4g)衍生物.与常规加热方法相比,微波辐射法具有反应时间短、产率高、后处理方便、环境友好等优点,所有化合物均经IR,1H MMR和元素分析确定.     

A new ion-exchange adsorbent with paramagnetic properties for the separation of genomic DNA

A new ion-exchange adsorbent (IEA) derived from Fe(3)O(4)/SiO(2)-GPTMS-DEAE with paramagnetic properties was prepared. Fe(3)O(4) nanoparticles were firstly prepared in water-in-oil microemulsion. The magnetic Fe(3)O(4) particles were modified in situ by hydrolysis and condensation reactions with tetraethoxysilane (TEOS) to form the core-shell Fe(3)O(4)/SiO(2). The modified particles were further treated by 3-glycidoxypropyltrimethoxysilane (GPTMS) to form Fe(3)O(4)/SiO(2)-GPTMS nanoparticles. Fe(3)O(4)/SiO(2)-GPTMS-DEAE nanoparticles (IEA) were finally obtained through the condensation reaction between the Cl of diethylaminoethyl chloride-HCl (DEAE) and the epoxy groups of GPTMS in the Fe(3)O(4)/SiO(2)-GPTMS. The obtained IEA has features of paramagnetic and ion exchange properties because of the Fe(3)O(4) nanoparticles and protonated organic amine in the sample. The intermediates and final product obtained in the synthesis process were characterized. The separation result of genomic DNA from blood indicated that Fe(3)O(4)/SiO(2)-GPTMS-DEAE nanoparticles have outstanding advantages in operation, selectivity, and capacity.     

SnO2 nanosheets grown on graphene sheets with enhanced lithium storage properties

We demonstrate a new hydrothermal method to directly grow SnO(2) nanosheets on a graphene oxide support that is subsequently reduced to graphene. This unique SnO(2)/graphene hybrid structure exhibits enhanced lithium storage properties with high reversible capacities and good cycling performance.     

α-Fe2O3 nanotubes with superior lithium storage capability

Polycrystalline α-Fe(2)O(3) nanotubes with thin walls have been synthesized by one-step template-engaged precipitation of Fe(OH)(x) followed by thermal annealing. In virtue of the unique structural features, these α-Fe(2)O(3) nanotubes exhibit superior lithium storage capabilities with exceptional high-rate capacity retention as a potential anode material for lithium-ion batteries.     

矩阵方程AXB+CYD=E的对称极小范数最小二乘解

对于任意给定的矩阵A∈Rm×n,B∈Rn×s,C∈Rm×k,D∈Rk×s,E∈Rm×s,本文利用矩阵的Kmnecker积和Moore-Penrose广义逆,研究矩阵方程AXB CYD=E的对称极小范数最小二乘解,得到了解的表达式．并由此给出了矩阵方程AXB=C的双对称极小范数最小二乘解的表达式．此外,我们还给出了求矩阵方程AXB=C的双对称极小范数最小二乘解的数值算法和数值例子．     

Three-dimensional image reconstruction of an Hα flare on 26 March 2001

Three-dimensional (3D) image reconstruction of an Hα flare near the solar disk center, is done by a series of line-center and off-line-center filtering observation, according to the physical meaning of contribution function based on the line formation theory. The contribution function represents the contribution from stellar atmospheric layers to the emergent specific intensity and describes the depth distribution of escape photons. In this paper, an Hα flare of 26 March 2001 is used to illustrate the 3D line-of-sight reconstruction and its development     

Analysis of lateral-spread photorefractive planar lenses

The photorefractive planar lens for converting a vertical incident plane wave to a lateral-spread spherical wave and vice versa, is suggested. Using the two-beam coupled-wave theory, the coupled wave equations are derived and their half-analytical solutions are also given in terms of an infinite series. The diffraction properties (beam profiles, diffraction efficiency) of the local volume grating in the lens are presented. And the focusing property of the lens is discussed and compared with that of an ideal convergent spherical wave. It is demonstrated that the suggested photorefractive planar lens shows a good focusing effect.