导电高分子吸波材料制备方法研究进展

作为一种新型的多功能材料,导电高分子吸波材料成为近年来研究的热点.重点阐述了近年来国内外导电高分子吸波材料的制备方法,包括纳米管、纳米线高分子吸波材料的模板法、电纺丝技术法等以及复合型导电高分子吸波材料的制备方法,并展望了导电高分子吸波材料的发展前景.     

Quantitative T 2 measurement of a single voxel with arbitrary shape using pinwheel excitation and CPMG acquisition

Objective The aim of this study is to present a new approach for making quantitative single-voxel T ₂ measurements from an arbitrarily shaped region of interest (ROI), where the advantage of the signal-to-noise ratio (SNR) per unit time of the single-voxel approach over conventional imaging approach can be achieved. Materials and methods Two-dimensional (2D) spatially selective radiofrequency (RF) pulses are proposed in this work for T ₂ measurements based on using interleaved spiral trajectories in excitation k-space (pinwheel excitation pulses), combined with a summed Carr–Purcell Meiboom–Gill (CPMG) echo acquisition. The technique is described and compared to standard multi-echo imaging methods, on a two-compartment water phantom and an excised brain tissue. Results The studies show good agreement between imaging and our method. The measured improvement factors of SNR per unit time of our single-voxel approach over imaging approach are close to the predicted values. Conclusion Measuring T ₂ relaxation times from a selected ROI of arbitrary shape using a single-voxel rather than an imaging approach can increase the SNR per unit time, which is critical for dynamic T ₂ or multi-component T ₂ measurements.     

2,2'-双[4-(3-氨基苯氧基)苯基]丙烷的合成

提出了以间二硝基苯和双酚A为原料经缩合和水合肼催化还原合成聚酰亚胺的单体2,2'-双[4-(3-氨基苯氧基)苯基]丙烷的新工艺,考察了各类工艺条件对目标产物收率的影响,得到最适宜反应条件,在优化条件下,总收率为85.5%.HPLC面积归一法测定目标产物纯度为99.97%,并用元素分析和红外光谱对目标产物进行了表征.     

驾驶状态实时监测系统设计

为了对驾驶员的驾驶状态进行有效地监测,基于驾驶员握力、方向盘转角和驾驶员头部位置3种驾驶信息,通过分析驾驶过程中的内在规律,提出了一种滑动时间窗的提取方法,使用该方法提取出了握力幅值疲劳度、转角标准差疲劳度、转角频数疲劳度和头位偏离疲劳度4种特征参数,并结合神经网络技术,建立了驾驶状态实时监测系统。研究表明:所设计的驾驶状态实时监测方法的识别正确率可达90.4%,且监测系统实时性强、监测效果理想、获取信息直观、警示方式多功能化,为驾驶状态的特征提取和实时监测系统的研究提供了有益的参考。     

昆明城市河道产汇流特性分析

基于城区河道下垫面条件与天然河道差异大的特点,根据实测暴雨洪水资料,分析昆明市城区河道(即发源于城区)暴雨空间分布、降雨径流关系(产流)及汇流参数(纳希瞬时单位线n、k值),并用实测暴雨洪水资料进行检验.结果表明:下垫面条件改变后,产流机制与天然状况截然不同,而汇流特性彼此一致,由此模拟的洪水过程与实测过程吻合较好,该分析对类似城市城区河道整治工程洪水计算将具有一定的借鉴参考作用.     

重钢高碱度烧结矿的生产

本文旨在根据重钢15年来的生产实践,介绍以低品位铁矿粉为主要原料的高碱度烧结矿的生产工艺特点,产品性能以及在高炉的冶炼效果,并对存在的某些问题进行初步探索,也是对我们15年来工作进行的总结。     

Surfactant to dye binding degree-based methodology for the determination of ionic amphiphilic compounds

A new analytical measurement parameter based on the effect of amphiphilic substances on the degree of binding of a surfactant to dye molecules, which induce the formation of surfactant premicellar aggregates, is presented. The theory for dye-surfactant intermolecular interactions in mixed surfactant systems, which assumes a mononuclear model for the formation of dye-induced premicellar aggregates, has been used to derive an expression that provides linear calibrations for the determination of amphiphilic compounds. The dye-surfactant interactions involved have been investigated, and the variables affecting the measurement analytical parameter have been discussed. The analytical applicability of the surfactant-dye binding degree method is demonstrated by quantifying major anionic surfactants at the nanograms-per-milliliter level and determining the total concentration of these amphiphilic substances in sewage samples (average recoveries ranged from 98 to 102%).