非饱和土土力学工程应用方法

通过引入文[1]提出的广义朗肯土压力计算公式,本文针对非饱和土主动(被动)土压力计算问题提出了工程应用方法,能够把非饱和土土压力理论应用于实际工程。该方法可以推广到非饱和土地基承载力、边坡稳定等其他领域,从而为非饱和土土力学理论应用于工程实践提供了一个新的思路。     

Chemically Amplified Resist Based on Dendritic Molecular Glass for Electron Beam Lithography

A novel dendritic molecular glass(MG) containing adamantane core(AD-15) was synthesized and characterized. It exhibits good solubility in common organic solvents and a stable amorphous state at room temperature, which contributes to forming films with different thicknesses by spin-coating. The thermal analysis of AD-15 indicates that no apparent glass transition temperature(T_g) is observed before the thermal decomposition temperature(T_d=160 ℃). The good thermal resistance suggests that it can satisfy the lithographic process and is a candidate for photoresist materials. The patterning properties of AD-15 resist were evaluated by electron beam lithography(EBL). By optimizing the lithographic process parameters, AD-15 resist can achieve 40 nm half-pitch patterns with a line-edge roughness of 4.0 nm. The contrast and sensitivity of AD-15 resist were 1.9 and 67 μC/cm², respectively. Compared with the commercial PMMA(950k) electron beam resist, the sensitivity of AD-15 resist increases by 6 times. This study provides a new example of molecular glass resist with high resolution and sensitivity for EBL.     

Photosensitive acrylate copolymer for electrodeposition photoresist

A photosensitive random copolymer UPDHES was prepared by introducing the acrylate groups into the side chain of the copolymer composed of N,N-dimethylaminomethyl methacrylate (DMAEMA), 2-hydroxyethyl acrylate (HEA), 2-ethylhexyl acrylate (EHA), and styrene (St) (PDHES). The molecular structure of UPDHES was characterized by FTIR and ¹H NMR analyses. Self-assembling of the random copolymer UPDHES in water formed positively charged photosensitive particles, and the particles were measured by TEM to be spherical-like nano-particles range from 20–90 nm. The oriented deposition of the particles on gold electrode was investigated with the cyclic voltammetry and TEM under low applied voltage. The influence of high applied voltage on current density in electrodeposition process and thickness of films were investigated also. Besides, the photopolymerization rate and final C=C conversion reached to the highest values with 3 wt % Irgacure 1173 addition, whereas decreased as further added. Moreover, an exposure-development procedure of electrodeposition UPDHES film produced developed diagram with resolution of 15 μm.     

扩张流变法研究表面活性剂在界面上的聚集行为

近年发展起来的界面流变测定技术在研究界面性质方面具有许多独特之处.本文结合我们的工作,总结了近年来有关该技术在表面活性剂界面聚集行为研究中的应用,讨论了扩张频率、表面活性剂浓度及疏水链长、无机盐和温度对表面扩张流变行为的影响,同时探讨了小分子表面活性剂与高分子表面活性剂表面扩张流变行为的区别以及小分子表面活性剂在气/液界面与液/液表面的扩张流变性的差异.大量研究表明,借助于界面流变性的测定不仅可以研究发生在界面上和界面附近的微观弛豫过程,而且可以探讨界面上超分子聚集体的形成,进而为乳状液和泡沫等分散体系的稳定性提供依据.     

光敏感三臂星形聚[甲基丙烯酸2-(二甲氨基)乙酯]的合成及其光敏性能研究

以香豆素为光敏感基元,通过多步反应制备了三臂ATRP引发剂C-Br3,然后以CuBr/PMDETA为催化体系、甲基丙烯酸2-(二甲氨基)乙酯(DMAEMA)为单体,ATRP聚合法制备了三臂星形聚合物C-(PDMAEMA)3.用傅里叶变换红外光谱仪(FTIR)、紫外-可见光分光光度计(UV-Vis)和核磁共振仪(1H-NMR)等对C-Br3及聚合物进行了结构表征.研究表明,该三臂星形聚合物可在水中直接形成胶束,且该聚合物可在365和254 nm交替紫外光照下发生可逆光二聚反应.纳米粒度跟踪显示,光照前其胶束粒径为(87.7±27.8)nm、呈高斯分布;而在365和254 nm光反应后,聚合物胶束粒径大小与分布仅发生微弱变化.这可能是因为在光二聚反应前后,聚合物的双亲结构变化微弱所致.     

Study on Z-scan characteristics of multilayer nonlinear media using coordinate transformation method

We present a method that combines coordinate transformation and Crank-Nicholson finite difference scheme to simulate numerically Z-scan measurements of a multilayer nonlinear medium or a complicated multilayer structure. The method would be useful to design and optimize optical limiters and to determine the nonlinearities of cascading medium layers. The method has given a guideline for determining the characteristics of multilayer medium.     

First-principles study of ferromagnetism in N doped TiO2 and TiO

N doped TiO is nonmagnetic, in which spin-split impurity states are not induced near the Fermi energy (E_F) by N dopant. N doped TiO₂ along with transition-metal (TM) doped TiO is magnetic, in which spin-split impurity states are induced across E_F. The magnetic moment is determined by the 3d4s electron configurations and the valence states of TM-dopant ions when they substitute Ti. Hence, the origin of ferromagnetism of N doped TiO₂ and TiO is not closely related to the width of the band gaps of host oxides, but would be crucially related to that if the dopant can induce spin-split impurity states near E_F.     

疏水缔合效应对聚丙烯酰胺类水溶液结构和流变性质的影响

以聚合物驱油为背景,研究了部分水解聚丙烯酰胺(HPAM)和缔合型部分水解聚丙烯酰胺(AHPAM)水溶液的结构与流变性质的差别.通过粘度法和静态激光光散射法得到了所分析的聚丙烯酰胺的分子量,用动态激光光散射法和粘度法分析了特定AHPAM分子缔合形态,并用流变学法测定了AHPAM在地层温度与矿化度条件下的线性粘弹性与非线性流变特性.着重讨论了临界缔合浓度的概念,研究了结构和流变性质的关系,以及分析了缔合对聚合物驱油的可能影响.实验结果表明,AHPAM水溶液在宽浓度范围存在分子缔合;一般临界缔合浓度的概念实际反映在进入亚浓溶液范围分子间缔合的效应,剪切速率约为10 s-1时,剪切粘度突降数倍,反映缔合结构在剪切场中的变化,该现象在高缠结浓度下较不明显;拉伸粘度随拉伸速率变化与HPAM定性不同,该拉伸特性反映了疏水缔合近程作用的本质.     

聚乙烯醇存在下钌(Ⅱ)-氯化亚锡-结晶紫高灵敏显色反应体系的研究

本文研究了在聚乙烯醇存在下钌(Ⅱ)-氯化亚锡-结晶紫离子缔合体系的高灵敏显色反应。离子缔合物的最大吸收峰位于550nm处,摩尔吸光系数为1.1×10~6L.mol~(-1)cm~(-1).钌含量在0.2—2.8μg/25mL范围内符合比尔定律。对外来离子的干扰和分离进行了研究。拟定的方法可用于矿石和一些低品位贵金属物料中钉的分析。