含改性松香的丁二醇二缩水甘油醚固化反应动力学研究

设计了含改性松香无苯环的环氧固化体系和无松香的对照体系,分别是无松香体系Ⅰ：丁二醇二缩水甘油醚（BDGE）和甲基六氢苯酐（MeHHPA）;无规体系Ⅱ：丙烯酸松香（AR）、BDGE和MeHHPA;有规体系Ⅲ：丙烯酸松香基环氧树脂（ARE,由AR和BDGE预聚而来）和MeHHPA。对三体系的固化反应应用动态示差扫描量热仪（DSC）进行了研究,利用KAS法求得不同转化率下的表观活化能,通过整个反应过程反应活化能的变化,得到了三体系反应的内在机理,结果发现松香基的引入及引入顺序都对固化反应产生影响。     

分数阶模糊时滞神经网络模型解的存在唯一性和有限时间稳定性

本文介绍了一类分数阶模糊时滞神经网络模型.利用压缩映射原理,讨论了带时滞的分数阶神经网络模型解的存在性和唯一性,并根据Gronwall不等式结合分数阶微分方程的性质,证明了分数阶神经网络模型平衡点的有限时间稳定性,给出了有限时间稳定性的判断准则.最后,给出数值仿真说明了理论结果的正确性.     

外场下压力及屏蔽对无限深量子阱中施主结合能的影响

考虑外加磁场、压力及屏蔽效应,利用变分方法数值计算GaN/AlxGa1-xN无限深量子阱系统中的杂质态结合能。给出结合能随磁场和阱宽的变化关系,同时讨论了有无屏蔽时的区别。结果表明:在磁场和压力作用下,结合能随阱宽的增大而减小;阱宽和压力一定时,结合能随磁场的增大而增大。屏蔽效应使得有效库仑吸引作用减弱而导致杂质态结合能显著下降。屏蔽效应对结合能的影响随压力增大而增强,随磁场强度增大而减弱。     

中国紫胶树脂基本组成的研究

定量测定了紫胶树脂基本成分的含量；分离得到了紫胶树脂 状脂肪酸和环状萜烯酸的代表物－－紫胶桐酸和壳脑酸。研究发现国产紫胶中软树脂含量高于印度紫胶。结果证明国产紫胶与印度胶在组成和树脂分子构成方面基本一致。     

Trace analysis of parabens,triclosan and related chlorophenols in water by headspace solid-phase microextraction with in situ derivatization and gas chromatography–tandem mass spectrometry

An in situ derivatization solid-phase microextraction method has been developed for the determination of parabens, triclosan and related chlorophenols in water. Acetylated derivatives are selectively determined using gas chromatography with tandem mass spectrometry. Parameters affecting both derivatization and SPME procedures, such as fiber coating, extraction mode, temperature, volume of derivatizating reagent and ionic strength, are studied and optimized through a multifactorial experimental design. The performance of the method is studied in terms of accuracy, linearity, precision and limits of detection. Quantitative recoveries (≥82%) and satisfactory precision (RSD ≤ 12%) are obtained. Limits of detection at the low picogram per millilitre level are achieved for all target compounds. Linearity is studied in a wide range of concentrations and an analysis of variance with a lack-of-fit test is run to validate the calibration data. Extraction time profiles are also obtained. Finally, the applicability of the proposed method is demonstrated for several real samples including river water, wastewaters and swimming pool water. Since no matrix effects are observed, quantification can readily be carried out by external calibration with ultrapure water standards.     

大视角两步彩虹全息术

本文巧妙地运用了全息图的光路可逆性,采用两面反射镜与小面积全息图相结合,制得了视场角接近180°的大视角彩虹全息图.整个过程分两步完成,无需任何特殊的光学元件.文中给出了实验结果,并进行了讨论.     

How Do Cultural Classes Emerge from Assimilation and Distinction? An Extension of the Cucker-Smale Flocking Model

When cultural tastes are not neutral but hierarchically matched to social status, people assimilate themselves to higher status by consuming cultural goods while distinguishing themselves from lower status by developing new tastes. Extending the Cucker-Smale model for mutual influence among agents, we examine when and how many cultural classes emerge from continuous distributions of tastes and what conditions those classes satisfy, through the assimilation-distinction mechanism. We simulate the models with different initial distributions of tastes (uniform, normal, and chi-square), given various ranges of 2 parameters: (a) the strength and (b) the range of distinction relative to assimilation. Tastes are flocking and cultural classes emerge when the range of assimilation is much larger than that of distinction. The number of classes increases with the strength of distinction, whereas the distance between classes equals the range of distinction. Some properties of emergent classes are mathematically proved. First, in a two-class system, the stronger distinction, the larger the upper class. Second, in a three-class system, the middle class is necessarily larger than the lower class and likely larger than the upper class. Third, a 3-class system cannot emerge if distinction is weaker than assimilation. These properties are universal and do not depend on the initial distribution of cultural tastes. This independence predicts homogeneous cultural classes emerging across different social conditions. Also, the cultural middle class as the largest group may explain why subjective class consciousness is often higher than objective position. Unless assimilating efforts can reach an infinite range, there emerges a cultural outcast at the lowest end of the cultural hierarchy.     

The lowest electronic states of Ne2 +, Ar2 + and Kr2 +: comparison of theory and experiment

Non-relativistic configuration interaction (CI) ab initio calculations using large basis sets have been carried out to determine the potential curves of the first electronic states of Ne₂ ⁺, Ar₂ ⁺ and Kr₂ ⁺. The spin—orbit interaction was treated assuming that the spin—orbit coupling constant is independent of the internuclear separation (R). For Ar₂ ⁺, calculated dissociation energies and equilibrium separations are in good agreement with experimental results. The calculations for Ne₂ ⁺ suggest that the lowest vibrational level of the I(1/2u) ground state observed by threshold photoelectron spectroscopy by Hall et al. [1995, J. Phys. B: At. molec. opt. Phys., 28, 2435] and assigned to either ν = 0 or ν = 2 actually corresponds to ν = 4. The calculations also predict the I(1/2g) state of Ne₂ ⁺ and Ar₂ ⁺ to possess a double-well potential and that of Kr₂ ⁺ to be repulsive at short range and to only possess a single shallow well at large internuclear separation. The ab initio calculations provide an explanation for the observation made by Yoshii et al. [2002, J. chem. Phys., 117, 1517] that Kr₂ ⁺ and Xe₂ ⁺ dissociate after photoemission from the II(1/2u) state to the I(1/2g) state whereas Ar₂ ⁺ does not.     

铝球弹丸高速正撞击薄铝板穿孔研究

 低地球轨道上的航天器易受到微流星体及空间碎片的超高速撞击，导致其严重的损伤甚至灾难性的失效。撞击损伤特性研究是航天器防护设计的一个重要问题。通过铝球弹丸超高速正撞击薄铝板的实验研究和数值模拟，证明了AUTODYN-2D软件数值模拟预测薄铝板超高速撞击穿孔直径的有效性。通过对弹丸直径、弹丸撞击速度和薄铝板厚度影响薄铝板超高速撞击穿孔直径的数值模拟，以及利用实验结果和数值模拟结果拟合的曲线，得到了铝球弹丸超高速撞击薄铝板的穿孔规律以及影响薄铝板超高速撞击穿孔直径的主要因素。