3-Pre-李超代数

通过给出3-pre-李超代数的概念及O-超算子的定义, 讨论3-pre-李超代数的基本性质, 并借助得到的邻接3-李超子代数构造经典3-Lie Yang-Baxter超方程的解.     

亚共析20CrMnTiA钢的超塑性研究

超塑成形技术已被广泛应用于兵工及民用产品中 ,其中对工业上大量应用的亚共析钢超塑性行为的研究却鲜有报道 ,该文对常用的亚共析 2 0CrMnTiA钢的超塑性行为进行了探讨 ,找出了超塑拉伸时应变速率和温度的最佳匹配 ,对制定其超塑成形工艺具有一定的参考价值 ,并由实验结果得出了超塑性变形时的应变速率敏感指数m值。同时初步探讨了亚共析钢获得超塑性的显微组织特点     

浅谈中压法生产硝酸装置中存在的腐蚀问题

列举了中压法生产硝酸装置中存在的设备腐蚀和管道腐蚀等现象,通过研究其腐蚀机理,结合多家企业生产硝酸的实际经验,对涉及到的腐蚀问题提出了处理措施。     

超声波对微细粉体制备的影响的研究

研究在湿法研磨的基础上加入超声波的空化爆破作用及分散作用，尝试用一种超声波空化加机械研磨的方法来制备超细微粉。试验证明，采用这种方法可以制造出纳米级的颗粒，该方法容易实现工业技术。     

集值映射最优化问题超有效解集的连通性

本文在局部凸空间中对集值映射最优化问题引入超有效解的概念．首先研究了超 有效点的一些重要特性．其后证明了当目标函数为锥类凸的集值映射时，其目标空间里 的超有效点集是连通的；若目标函数为锥凸的集值映射时，其超有效解集也是连通的．     

纯液体的表面现象及相变过程的讨论

讨论了纯液体的表面现象及相变过程的有关问题     

固体超强酸S2O8^2-/ZrO2-SiO2-Sm2O3催化合成溴代正辛烷的研究

溴代正辛烷是重要的有机精细化工产品中间体[1],主要用于合成脂肪醇聚氧乙烯醚,烷基酚聚氧乙烯醚和脂肪醇聚氧乙烯醚硫酸盐等表面活性剂;也是合成菌毒清的中间体.     

低信噪比下的二维联合线性布雷格曼迭代快速超分辨成像算法

针对实际逆合成孔径雷达(ISAR)成像时带宽有限、方位孔径稀疏的小角度回波数据条件下,常规算法的成像分辨率不高等问题,基于压缩感知理论,提出了一种低信噪比条件下的二维联合布雷格曼迭代快速ISAR超分辨成像算法.首先,将雷达回波构建为距离频域-方位多普勒域的二维稀疏表示模型,在此基础上,将二维超分辨成像问题转换为二维联合压缩感知的稀疏重构问题;其次,为了避免重构时向量化操作带来的复杂度,提出了二维联合布雷格曼迭代算法,为实现快速重构,将加权残量迭代、估计停滞步长与感知矩阵条件数优化三种加快收敛速度的思想相结合,既利用了布雷格曼迭代在低信噪比条件下的重构能力又能保证快速成像.最后仿真实验结果表明在欠采样和低信噪比条件下本文算法能够缩短成像时间,且具备更好的噪声鲁棒性.     

Surface effect on the nonlinear forced vibration of cantilevered nanobeams

The nonlinear forced vibration behavior of a cantilevered nanobeam is investigated in this paper, essentially considering the effect due to the surface elastic layer. The governing equation of motion for the nano-cantilever is derived, with consideration of the geometrical nonlinearity and the effects of additional flexural rigidity and residual stress of the surface layer. Then, the nonlinear partial differential equation (PDE) is discretized into a set of nonlinear ordinary differential equations (ODEs) by means of the Galerkin’s technique. It is observed that surface effects on the natural frequency of the nanobeam is of significance, especially for the case when the aspect ratio of the nanobeam is large. The nonlinear resonant dynamics of the nanobeam system is evaluated by varying the excitation frequency around the fundamental resonance, showing that the nanobeam would display hardening-type behavior and hence the frequency-response curves bend to the right in the presence of positive residual surface stress. However, with the negative residual surface stress, this hardening-type behavior can be shifted to a softening-type one which becomes even more evident with increase of the aspect ratio parameter. It is also demonstrated that the combined effects of the residual stress and aspect ratio on the maximum amplitude of the nanobeam may be pronounced.     

A convenient method for preparation of hydroxyl silicone oils with ring opening polymerization of octamethylcyclotetrasiloxane (D4)

Hydroxyl silicone can be prepared at a mild polymerization temperature with a moderately high yield via ring opening polymerization of D4 catalyzed by rare earth solid super acid SO₄^2?/TiO₂/Ln³⁺. The outstanding advantage of the method was that the viscosities of the products can be conveniently controlled by adjusting polymerization time, temperature, and the amount of water. The products were characterized by size-exclusion chromatography, ¹H-nuclear magnetic resonance, and Fourier transform-infrared spectroscopy. A cationic coordination-insertion polymerization mechanism was also proposed.