Nd（P_（507））_3－Al（i－Bu）_3催化马来酸酐与环氧丙烷开环交替共聚

本文研究了马来酸酐和环氧丙烷交替共聚，发现Ｎｄ（Ｐ_（５０７））_３－Ａｌ（ｉ－Ｂｕ）_３是马来酸酐（ＭＡｎ）和环氧丙烷（ＰＯ）交替共聚的良好催化剂，并用红外光谱，核磁共振谱研究了共聚物的结构。     

Chemical ionization mass spectrometry of nitrosamines

The mass spectra of eight nitrosamines have been recorded, with excitation by chemical ionization (CI) and electron impact (EI). Comparison of the intensities of the base peaks under CI and El conditions gives intensity ratios in the range 1.4-1.9 for low resolution measurements and up to 10 for high resolution measurements, confirming the enhanced sensitivity available in the CI mode.     

Nd(naph)3-Al(i-Bu)3催化邻苯二甲酸酐与环氧丙烷交替共聚

Ｎｄ（ｎａｐｈ）３Ａｌ（ｉＢｕ）３催化邻苯二甲酸酐与环氧丙烷交替共聚房江华黄士力（宁波师范学院化学系，宁波３１５０２０）沈之荃（浙江大学高分子科学与工程学系，杭州３１００２７）关键词环烷酸钕，交替共聚，邻苯二甲酸酐，环氧丙烷分类号Ｏ６４３／ＴＱ３...     

4-Phosphoryl Pyrazolones for Highly Selective Lithium Separation from Alkali Metal Ions

Effective receptors for the separation of Li⁺ from a mixture with other alkali metal ions under mild conditions remains an important challenge that could benefit from new approaches. In this study, it is demonstrated that the 4-phosphoryl pyrazolones, H L ²-H L ⁴, in the presence of the typical industrial organophosphorus co-ligands tributylphosphine oxide (TBPO), tributylphosphate (TBP) and trioctylphosphine oxide (TOPO), are able to selectively recognise and extract lithium ions from aqueous solution. Structural investigations in solution as well as in the solid state reveal the existence of a series of multinuclear Li⁺ complexes that include dimers (TBPO, TBP) as well as rarely observed trimers (TOPO) and represent the first clear evidence for the synergistic role of the co-ligands in the extraction process. Our findings are supported by detailed NMR, MS and extraction studies. Liquid-liquid extraction in the presence of TOPO revealed an unprecedented high Li⁺ extraction efficiency (78 %) for H L ⁴ compared to the use of the industrially employed acylpyrazolone H L ¹ (15 %) and benzoyl-1,1,1-trifluoroacetone (52 %) extractants. In addition, a high selectivity for Li⁺ over Na⁺, K⁺ and Cs⁺ under mild conditions (pH ∼8.2) confirms that H L ²-H L ⁴ represent a new class of ligands that are very effective extractants for use in lithium separation.     

纳米金探针检测Hg 2+离子

利用Hg2＋的核酸适体修饰纳米金形成探针建立了一种定量检测Hg2＋离子的方法. Hg2＋适体吸附在纳米金表面, 使纳米金的稳定性增强, 抑制氯化钠对纳米金的团聚作用. 溶液中有Hg2＋离子存在时, 由于适体与纳米金的吸附作用小于适体与Hg2＋离子的亲和作用, 纳米金失去适体保护在氯化钠作用下发生团聚. 溶液颜色由红变蓝, 紫外-可见光谱最大吸收峰由520 nm红移至620 nm. 在优化条件下, 吸光度的比值(A620/A520)与Hg2＋离子浓度在5.0×10－9～7.2×10－7 mol•L－1范围内呈线性关系, 检测限可达3.3×10－10 mol•L－1. 研究了K＋, Ca2＋等常见离子的干扰, 结果表明该方法具有良好的选择性.     

基于在线HHT和SVM的汽油机轻微漏气故障识别方法

针对汽油机轻微漏气故障会被闭环反馈控制所掩盖,提出了一种基于在线希尔伯特变换(Hilbert-Huang Transform,HHT)和支持向量机(Support vector machine,SVM)的两阶段微小故障识别方法(Online HHT-SVM,OHS).第一阶段在嵌入式两滑动时间窗内通过HHT对发动机空燃比数据流进行在线时频分析,以实时获取空燃比发生异常的时刻;第二阶段通过SVM对异常时刻的数据流故障模式进行离线识别.根据氧传感器信号特征,对经验模态分解(Empirical mode decomposition,EMD)算法进行了改进,并从理论上进行了证明.基于两款发动机的实际运行数据验证了该方法的有效性.     

稀土催化邻苯二甲酸酐与环氧丙烷交替共聚

研究了用稀土络合催化剂Ｎｄ（ａｃａｃ）３－Ａｌ（ｉ－Ｂｕ）３催化邻苯二甲酸酐（ＰＡ）和环氧丙烷（ＰＯ）开环交替共聚（ａｃａｃ＝乙酰丙酮）．考察了共聚合反应特征，用红外光谱、核磁共振表征了共聚物的结构。共聚反应的动力学研究表明共聚与单体浓度呈一级关系，与催化剂浓度呈一级关系，表现活化能为１．２８７×１０￣５Ｊ／ｍｏｌ。     

Chromatographic separations in a nanocapillary under pressure-driven conditions

We report a unique property of nanocapillaries for chromatographic separations of ionic species. Due to the electric double layer overlap, ions are unevenly distributed inside a nanochannel, with counterions enriched near the wall and co-ions concentrated in the middle of the channel. As a pressure-driven flow is induced, the co-ions will move faster than the counterions. This differential transport results in a chromatographic separation. In this work, we introduce the fundamental mechanism of this separation technology and demonstrate its application for DNA separations. An outstanding feature of this technique is that each separation consumes less than 1 pL sample and generates less than 0.1 nL waste. We also apply this technique for separations of DNA molecules, and efficiencies of more than 1,00000 plates per meter are obtained.     

Fe-Al络合催化苯乙烯-马来酸酐交替共聚

应用Ｆｅ（ａｃａｃ）３ Ａｌ（ｉ Ｂｕ）３（ａｃａｃ＝乙酰丙酮）催化苯乙烯 马来酸酐共聚,制得富于交替的白色粉末共聚物．共聚反应动力学研究表明,共聚反应与单体浓度呈一级关系,表观活化能为４８６ｋＪ／ｍｏｌ．     

微流控光谱分析进展

本文对新兴的微型分析技术———微流控分析中的光谱检测技术进行了综合评述 ,简介了微流控分析技术 ,并对该分析方法进行了展望