高分子专业毕业实习现状分析及措施研究

针对高分子材料科学与工程专业毕业实习存在的问题,结合国际工程认证要求以及学校对毕业生要求达到的毕业目标,提出了高分子专业毕业实习适合采取集中实习和分散实习相结合的方法。让毕业实习融入到毕业设计及毕业论文中,并使实习成为提前毕业设计和论文、就业、自谋出路的一部分,建立稳定的校外实习基地,提高学生毕业实习的质量,在巩固和深化他们自身专业理论水平的同时,提高其动手创造能力和思维创新能力,并使其综合工程素质得到提高。     

Laser photolysis of interaction of poly-guanylic acid (5′) with anthraquinone-2-sulfonate

The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly- guanylic acid (5′) in CH3CN-H2O (97:3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet anthraquinone-2-sulfonate and poly[G] demonstrate that the primary ionic radical pair, radical cation of poly[G] and radical anion of anthraquinone-2-sulfonate have been detected simultaneously. The free energy changes in the process of the electron transfer were also calculated.     

酶-过渡金属配合物催化的动态动力学拆分研究进展

动态动力学拆分是合成具有光学活性化合物最方便和最有效的方法之一. 酶和金属配合物的结合扩展了这个方法的使用范围, 该方法的主要特征是用酶催化拆分和金属催化原位外消旋化未反应的底物, 克服了经典动力学拆分最高产率只有50%的缺陷. 概述了近几年这方面的研究进展.     

麦滋林—S中Ao磺酸钠的高效液相色谱法测定

１引言 部分水解聚丙烯酸胺（ＨＰＡＭ）的应用领域相当广泛，在三次采油中主要作为流度控制剂。大庆油田的聚合物驱油技术从研究到现场应用已走过了十几年历程，现在应用规模已达到世界最大，年注入量高达７．５万吨，目前初步得到了完善，但有关聚合物浓度的检测技术，一直不能适应油田生产实际的需要。驱油用聚合物ＨＰＡＭ的浓度测试方法，现在一直沿用淀粉、碘化镉比色法和浊度法，这两种方法由于受溶液环境的限制，其应用的普适性很差，对不同生产工艺、批次的产品，要做不同的标准曲线，而且该两种方法用了易于挥发的溴水和冰醋酸，…     

两个三角不等式

定理１在任意△ＡＢＣ中，Ａ、Ｂ、Ｃ表示其三内角，则ｃｏｓ３Ａ＋ｃｏｓ３Ｂ＋ｃｏｓ３Ｃ≥３８．（等号当且仅当△ＡＢＣ为正三角形时成立）证明由三角恒等式ｃｏｓ３Ａ＋ｃｏｓ３Ｂ＋ｃｏｓ３Ｃ＝（２Ｒ＋ｒ）３－３ｓ２ｒ４Ｒ３－１（Ｒ、ｒ、ｓ为△ＡＢＣ的外接圆半...     

Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been applied in the experiment of neutron-rich nucleus 21N. The performance of those four Clovers have been tested with radioactive sources and in-beam experiments, and the main results including energy resolution, peak-to-total ratios, the variation of the hit pattern distribution in different crystals of one Clover detector with the energy of γ ray, and absolute full energy peak detection effciency curve, were presented.     

Resonant Third-Order Optical Nonlinearities of Poly（methyl methacrylate） Films Containing J-Like Aggregates of a Thiadicarbocyanine Dye

The third-order optical nonlinearities and responses of poly（methyl methacrylate） （PMMA） coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3＇-diethyl-2,2＇-thiadicarbocyanine iodide （DTDC1）, are measured by degenerate four-wave mixing （DFWM） technique under resonant conditions. The temporal profiles of the DFWM signal of PMMA coating films containing J-like aggregates of DTDC1 are found to consist of three components： i.e., the coherent instantaneous nonlinear response （electronic response） and the two slow responses uqth decay time constants of about 0.8ps and about 7.0ps. The electronic component of the effective third-order nonlinear susceptibility, χc^（3）, of one of the present films is as high as about 2.1×10^-8 esu, and the figure of merit of third-order nonlinearity F （F=χ^（3）/α） is evaluated to be about 1.9 ×10^-13 esu cm at 850nm.     

铝合金杯形件等温挤压成形工艺

材质为2A14铝合金深孔杯形毛坯件，由于壁薄，材料热变形温度范围窄，合金流变困难，若采用常规锻造的反挤压成形方法，势必造成杯体内、外壁变形不均，温度下降过快，变形抗力大，成形难度较大。等温成形工艺是零件毛坯精化和优化的一个重要途径，但对设备和模具的要求较高，成本高。因此运用有限元数值模拟结合试验对铝合金杯形件挤压成形工艺进行可行性研究，以减少研究试验成本。     

Influence of Interface Charge on Electrical Properties of ZnO／Si Heterojunction

The capacitance-voltage and current-voltage properties of the samples before and after annealing are investigated at 300 K and 195K. It is found that the interface charge plays an important role for the heterojunction properties. After annealing, the samples exhibit typical junction properties. The heterojunction shows a built-in potential 0.62eV consistent with the theoretical result 0.67eV. However, the sample exhibits more complex behaviour before annealing. The experimental results can be explained by heterojunction theory when, introducing interface charge, which suggests that the annealing can reduce interface charge and can improve the junction properties of the samples.     

相机标定的外界影响因素分析

针对相机标定结果易受外界因素干扰的问题,为了提高标定准确度,利用已有的摄像机针孔成像模型,采用自适应角点检测算法提取靶标图像中的特征点,标定结果以重投影横纵像素误差的平均值作为性能指标,对均匀光源的照度、标定图片数量以及标定靶标上棋盘格尺寸3个影响因子做了相应的分组对比实验。研究结果表明,选择亮度高的光源提升标定准确度达到38%以上;特征点数目156个时,仅需18张～22张标定图片;相对较小的棋盘格尺寸可以使得标定准确度提高50%。以上结果充分说明了光源、图片数量和棋盘格尺寸对于提高相机标定准确度具有重要意义。