烟碱石墨涂膜电极及PVC膜电极的研究

国内外现有的测定烟碱(尼古丁)的方法,都需要预先进行水汽带馏,再用重量法或分光光度法测定,重量法操作繁琐,分析一个样品需花30h,紫外分光光度法,仍必须预先进行水汽带馏,结果不够理想,目前国内药典还没有测定烟碱的方法。本文采用四苯硼钠-烟碱为活性物的石墨涂膜电极及PVC膜电极,直接测定烟叶及香烟产品提取液中烟碱的含量,所得结果与重量法基本一致,该电极制作简便,电极响应快,线性范围较宽,选择性较好。     

Experimental study of the time-resolved reflectivity of chromium film

The transient time-resolved reflectivity of chromium film is studied by femtosecond pump-probe technique with a 70-fs laser. Experimental results show that the reflectivity change increases with the power of the pump laser. The fast decrease of the reflectivity occurs between 0-200 fs which is mainly due to the electron-electron interaction. Subsequencely, the slower recovery of the reflectivity between 200-900 fs is mainly due to the electron-phonon coupling process. The reflectivity after 900 fs rises little to a near-constant value for the thermal equilibrium of the system. The experimental results can be explained properly with numerical simulation of the two-temperature model. It is helpful for understanding of the electron ultrafast dynamics in chromium film.     

巡游出租车运力规模动态调整回归树模型

针对巡游出租车运力规模调整指标体系的匮乏, 以宁波市出租车信息管理系统运营数据为基础, 梳理了巡游车运力规模调整的主要影响因素, 综合考虑各项运营指标, 构建了巡游车运力规模调整阈值回归树模型, 并采用方差分析的卡方自动交叉诊断器算法对模型进行标定. 最后, 耦合了万人拥有量、出租车在公交出行结构分担率、巡游车与网约车业务分担比以及乘客平均等候时间等指标在供需状态中的表征作用和重要性排序关系, 提出了巡游出租车运力规模动态调整机制及关键指标的阈值标准, 为城市巡游出租车运力规模调整提供理论依据和决策支持.     

Femtosecond laser induced microripple on PDMS surface

We find the femtosecond laser induced microripple beside the focused femtosecond laser spot and along the movement direction of the laser spot on polydimethylsiloxane （PDMS） surface. The microripple may be due to the melting of PDMS induced by femtosecond laser pulses and the subsequent cool-down solidification of the melting PDMS along with the movement of the femtosecond laser spot. This result will be helpful to understand the interaction between the femtosecond laser and the polymer.     

Valen席夫碱单核铜配合物的合成、热化学性质及其对粟酒裂殖酵母细胞作用的热动力学研究

以甲醇为溶剂,邻香草醛缩乙二胺席夫碱(H2vanen)与一水合醋酸铜[Cu(OAc)2·H2O]反应,合成了一种Valen席夫碱单核铜配合物[Cu(vanen)(H2O)].以盖斯定律为理论基础,设计了一个合理可行的热化学循环.根据该热化学循环,依次测定了各样品的标准摩尔溶解焓,进而求得配位反应的标准摩尔反应焓(θr m?H)为?(16.61±0.54)kJ/mol.再结合其他相关的文献值,求得配合物的标准摩尔生成焓(θf m?H)为?(756.5±2.4)kJ/mol.在32℃条件下,用热导式等温微量热仪测定了不同浓度配合物作用下粟酒裂殖酵母细胞的产热曲线,探讨了不同浓度的配合物对酵母菌生长的影响,分析了配合物的浓度与酵母菌代谢的生长速率常数k、抑制率I、最大发热功率Pmax、半抑制浓度IC50以及达到最大发热功率所需时间tmax等动力学参数之间的关系.分析结果表明,配合物对粟酒裂殖酵母细胞的生长具有低浓度促进、高浓度抑制的Hormesis效应.     

环氧化－6－豆甾酮的合成

以豆甾醇为原料，经Ａ／Ｂ环结构改造，所得双键化合物用过苯甲酸氧化，可高选择性、高产率地合成出２ａ，３ａ－二乙酰基－２２Ｒ，２３Ｒ－环氧－６－豆甾酮和２ａ，３ａ－环氧－２２Ｒ，２３Ｒ－环氧－６－豆甾酮。由此二化合物可较方便地制得２ａ，３ａ，２２Ｒ，２３Ｒ－四乙酰基－６－豆甾酮。