β-CD、DBS协同增敏美他环素的荧光光谱研究及分析应用

用荧光光度法研究了阴离子表面活性剂十二烷基苯磺酸钠(DBS)-β-环糊精(β-CD)体系对美他环素的协同荧光增敏作用。在β-CD-DBS体系中美他环素的荧光强度显著增强,由此建立了测定美他环素的新方法。结果表明：美他环素与DBS、β-CD生成摩尔比为1∶1∶1的三元包合物,其表观结合常数为1 294 L2·mol-2。美他环素浓度在1.7×10-7～8.8×10-5mol·L-1范围内与体系荧光强度呈线性关系,相关系数r为0.996 6,检测限为7.4×10-9mol·L-1。方法用于测定药物制剂中美他环素的含量,回收率在95%～106%之间,结果令人满意。     

乘幂法求矩阵特征向量与特征值的初始向量及循环控制

矩阵迭代法是求矩阵的第一阶特征值与特征向量的一种数值方法 .本文讨论了用矩阵迭代法求解矩阵的特征值与特征向量时的初始向量选取和循环控制条件     

具有储蓄功能的养老保险精算模型

本文建立了一个综合养老保险精算模型 ,把几种保险产品统一在模型中 ,模型包括延期支付的年金部分 ,终身寿险部分和还本部分 ,保险公司可以根据不同的实际情况 ,调整参数 ,通过不同参数的组合 ,获得不同的养老保险产品 .还本部分的引入 ,使得这种保险产品具有储蓄的性质     

Surface Functionalization of Fe3O4 Magnetic Nanoparticles via RAFT‐Mediated Graft Polymerization

Summary: Surface functionalization of Fe₃O₄ magnetic nanoparticles (MNP) via living radical graft polymerization with styrene and acrylic acid (AAc) in the reversible addition‐fragmentation chain transfer (RAFT)‐mediated process was reported. Peroxides and hydroperoxides generated on the surface of Fe₃O₄ nanoparticles via ozone pretreatment facilitated the thermally initiated graft polymerization in the RAFT‐mediated process. A comparison of the MNP before and after the RAFT‐mediated process was carried out using transmission electron microscopy (TEM) analysis, Fourier transform infrared (FTIR), and X‐ray photoelectron spectroscopy (XPS). Gel permeation chromatography (GPC) was used to determine the molecular weight of the free homopolymer in the reaction mixture. Well‐defined polymer chains were grown from the MNP surfaces to yield particles with a Fe₃O₄ core and a polymer outer layer. The resulting core–shell Fe₃O₄‐g‐polystyrene and Fe₃O₄‐g‐poly(acrylic acid) (PAAc) nanoparticles formed stable dispersions in the organic solvents for polystyrene (PS) and PAAc, respectively.

Schematic illustration of thermally induced graft polymerization of styrene and AAc with the ozone‐treated Fe₃O₄ MNP.     

Polypyrrole Nanospheres with Magnetic and Cell‐Targeting Capabilities

The preparation of polypyrrole/Fe₃O₄ nanospheres by a facile mini‐emulsion polymerization method is investigated using poly(ethylene glycol), poly(ethylene oxide), poly(vinyl alcohol), and hyaluronic acid as surfactants. Hyaluronic acid is deemed the most suitable surfactant since it results in well‐dispersed nanospheres of 80–100 nm, and offers the advantages of biocompatibility, cell adhesive property, and the availability of functional groups for attachment of other molecules. These polypyrrole/Fe₃O₄ nanospheres are magnetic and can be further functionalized with a cancer antibody, herceptin. Our results show that this combination of hyaluronic acid and herceptin results in high specific uptake of the nanospheres by cancer cells.

     

Unconventional Hamilton-type variational principles for nonlinear elastodynamics of orthogonal cable-net structures

According to the basic idea of classical yin-yang complementarity and modem dual-complementarity,in a simple and unified new way proposed by Luo,the unconven- tional Hamilton-type variational principles for geometrically nonlinear elastodynamics of orthogonal cable-net structures are established systematically,which can fully charac- terize the initial-boundary-value problem of this kind of dynamics.An important in- tegral relation is made,which can be considered as the generalized principle of virtual work for geometrically nonlinear dynamics of orthogonal cable-net structures in mechan- ics.Based on such relationship,it is possible not only to obtain the principle of virtual work for geometrically nonlinear dynamics of orthogonal cable-net structures,but also to derive systematically the complementary functionais for five-field,four-field,three-field and two-field unconventional Hamilton-type variational principles,and the functional for the unconventional Hamilton-type variational principle in phase space and the poten- tial energy functional for one-field unconventional Hamilton-type variational principle for geometrically nonlinear elastodynamics of orthogonal cable-net structures by the general- ized Legendre transformation given in this paper.Furthermore,the intrinsic relationship among various principles can be explained clearly with this approach.     

高锰酸钾-甲醛-荧光素-没食子酸丙酯化学发光体系的研究

高锰酸钾-甲醛-荧光素-没食子酸丙酯在酸性介质中有较好的发光特性,在最佳实验条件下,当没食子酸丙酯溶液浓度在8.0×10-6～2.0×10-3g/L范围内与化学发光强度有良好的线性关系(r=0.9960),对1.0×10-3g/L的没食子酸丙酯溶液平行测定11次,RSD为1.9%,检出限为5.6×10-6g/L。该法用于食用调和油中没食子酸丙酯的测定,结果令人满意。     

多层波纹钢板式干摩擦减振器实验研究

多层波纹钢板式干摩擦减振器具有结构简单、加工工艺好、减振效果显著等特点 ,具有广阔的应用前景 ,与传统的减振材料及结构相比 ,波纹钢板减振器具有耐高低温、耐腐蚀、承载能力更大、寿命更长以及可靠性更高等优点。本文研究了多层波纹钢板式干摩擦减振器制备工艺方法、动静态实验方法以及动静态特性 ,并研究了影响波纹钢板隔振性能的主要影响因素。实验结果表明 ,多层波纹钢板式干摩擦减振器具有良好的迟滞阻尼性能 ,减振器的刚度和能耗系数都随变形量的变化而呈非线性变化 :减振器的性能决定于钢板厚度、波纹高度、相对自由间隙和钢板层数等参数。对于不同参数的减振器 ,频响曲线的共振频率范围变化不大。该种减振器可以在较宽的频率范围工作。研究结果为多层波纹钢板减振器的进一步应用研究奠定了基础     

大应变、高应变率及高压强条件下混凝土的计算模型

给出了混凝土在高速撞击条件下一种新的计算模型 ,同以前的工作相比 ,它可以很好地模拟在撞击过程中混凝土靶的成坑、层裂情况以及混凝土靶内出现的断裂现象。计算的结果同以前的模型计算结果和实验数据进行了比较。     

关于线粘弹性动力学中各种变分原理

本文提出一条简单而统一的新途径,系统地建立了线粘弹性动力学中各种简化Gurtin型变分原理,文中首先给出一个很有用的以卷积表示的积分关系式,然后从该式出发,系统地导出成互补关系的五类变量、四类变量、三类变量、二类变量及一类变量简化Gurtin型变分原理,并清楚地阐明它们之间的内在联系,而且,还发现当前在国际上有广泛影响的力学变分原理方面的名著[1]及文[2]中,所给出的四个变分原理的泛函式均有误.本文除给出这四个正确的泛函式外,还建立了一些新的更一般广义变分原理。