薄透镜焦距测量中的测量条件选择

本文通过对薄透镜焦距测量中的测量条件的分析，说明了通过实验教学更好地提高学生实验能力的方法     

纳米半导体及其应用

纳米半导体硅薄膜是利用等离子增强化学气相淀积方法制备的，制备条件可以很好地进行调节控制。纳米硅薄膜由两种组元组成；纳米尺度晶粒级元和晶粒间的界面组元，即晶态相和晶界相组成，这对发展半导体器件，例如量子功能器件和薄膜敏感器件等是特别有价值的。     

扩展齐次平衡法与Backlund变换

将求解非线性演化方程的齐次平衡法进行了扩展,使其包含一个任意函数.此改进方法可得到耦合KdV-Burgers方程、KdV-Burgers方程、Boussinesq方程和一般KdV方程等许多非线性演化方程的Backlund变换和新的精确解.     

A PRIORI L_2 ERROR ESTIMATES FOR A NONLINEAR PARABOLIC SYSTEM BASED ON COMBINING THE METHOD OF CHARACTERISTICS WITH MIXED FINITE ELEMENT PROCEDURE

A nonlinear parabolic system is derived to describe incompressible nuclear waste-disposal contamination in porous media. A sequential implicit tirne-stepping is defined, in which the pressure and Darcy velocity of the mixture are approximated simultaneously by a mixed finite element method and the brine, radionuclid and heat are treated by a combination of a Galerkin finite element method and the method of characteristics. Optimal-order convergence in L2 is proved. Time-truncation errors of standard procedures are reduced by time stepping along the characteristics of the hyperbolic part of the brine, radionuclide and heal equalios, temporal and spatial error are lossened by direct compulation of the velocity in the mixed method, as opposed to differentiation of the pressure.     

Attachment of Gold Nanoparticles to Carbon Nanotubes

Carbon nanotubes were initially chemically modified with an H2SO4-HNO3 treatment, and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. These activated nanotubes were used as precursors for obtaining gold nanoparticles-attached nanotubes via simple electroless plating. This approach provides an efficient method for attachment of metal nanostructures to carbon nanotubes. Such novel hybrid nanostructures are attractive for many applications.     

Studies on Middle-Phase Microemulsions of Green Surfactant n-Dodecyl Polyglucoside C12G1.46

The three-phases behavior in the quaternary stsem of n-dodecyl polyglucoside C12G1.46/1-butanol/cyclohexane/water has been studied at 40℃ in terms of the variables γ and δ.Increasing δ at constant γcauses a phase inversion from an oil-in-water microemulsion in contact with excess oil(winsor I or 2) to a water-in-oil microemulsion in contact with excess water (winsor Ⅱor 2)via a middle-phase microemulsion in contact with excess oil and water(winsor Ⅲor 3).By taking into account the different solubilities of alkyl polyglucoside and 1-butanol in the oil phase,the composition of the hydrophile-lipophile balanced interfacial film in the middle of the three-phase body can be calculated.The effects of different oils and aqueous media on the phase behavior and on the composition of the interfacial film and the efficiency for alkyl polyglucoside to make equal weights of water and oil to a single phase were investigated.It was found that the oil molecules with small molecular volumes can improve the solubilizing efficiency of the surfactant to form single-phase microemulsion.In inorganic salt(NaCl) and acid(HCl) solutions,less 1-butanol is needed than that in alkali(NaOH) solution to form middle-phase microemulsion.     

Synthesis of Novel Carbosilane Dendrimers Based on Pentaerythritol

Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydrosilylation of allyl groups with HSiC13 and allylations of SiC1 groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, ^1H and ^13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting carbosilne dendrimers have been determined by vapor pressure osmometry.     

Synthesis of Glutamic Acid-based Cluster Galactosides and Their Binding Affinities with Liver Cells

Structurally well defined di-, tri- and tetra-valent cluster galactosides were synthesized in a convenient way.Oligo-glutamic acids were assembled as scaffolds. The presence of amine groups in these three ligands is expected to couple with drugs or genes for delivery. The binding affinities of these cluster galactoses to liver cells were determined by in vitro binding studies. Among them, the tetravalent cluster galactose (19) showed the highest affinity to liver cell. It is therefore a promising targeting device for the specific delivery of drugs or genes to parenchymal liver cells.     

粘度法研究PAM与R12SO3Na之间的相互作用

采用粘度法研究了纯水及含有NaCl和R_4OH(正丁醇)时, PAM(聚丙烯酰胺)与R_(12)SO_3Na(十二烷基磺酸钠)之间的相互作用。结果表明, 在所研究的范围内, PAM与R_(12)SO_3Na胶束之间能形成PAM-R_(12)SO_3Na胶束聚集体。但在纯水和NaCl溶液中, 两者之间的作用较弱。若体系中同时存在R_4OH时, 作用较强。可能是PAM分子中的—C=O —C—NH_2与混合胶束中的醇羟基以氢键相结合, 形成PAM-胶束聚集体, 所以体系的比浓粘度(ηsp/cp)随PAM浓度(cp)的降低而急剧增大, 表现出典型的聚电解质性质。     

Preliminary Study on Cordycepin-DNA Interaction by Raman Spectroscopy

The interaction of cordycepin with calf thymus DNA was investigated at physiological pH with drug/DNA molar ratio of 8. The Raman spectroscopy results indicated that the intercalation of high concentration cordycepin and the interaction of cordycepin with PO2 group led to a major reduction of B-form DNA structure in favor of A-form DNA.