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.     

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.     

Uniform AMoO4:Ln (A=Sr, Ba; Ln=Eu, Tb) submicron particles: Solvothermal synthesis and luminescent properties

Rare-earth ions (Eu³⁺, Tb³⁺) doped AMoO₄ (A=Sr, Ba) particles with uniform morphologies were successfully prepared through a facile solvothermal process using ethylene glycol (EG) as protecting agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the kinetic decays were performed to characterize these samples. The XRD results reveal that all the doped samples are of high purity and crystallinity and assigned to the tetragonal scheelite-type structure of the AMoO₄ phase. It has been shown that the as-synthesized SrMoO₄:Ln and BaMoO₄:Ln samples show respective uniform peanut-like and oval morphologies with narrow size distribution. The possible growth process of the AMoO₄:Ln has been investigated in detail. The EG/H₂O volume ratio, reaction temperature and time have obvious effect on the morphologies and sizes of the as-synthesized products. Upon excitation by ultraviolet radiation, the AMoO₄:Eu³⁺ phosphors show the characteristic ⁵D₀–⁷F_1–4 emission lines of Eu³⁺, while the AMoO₄:Tb³⁺ phosphors exhibit the characteristic ⁵D₄–⁷F_3–6 emission lines of Tb³⁺. These phosphors exhibit potential applications in the fields of fluorescent lamps and light emitting diodes (LEDs).     

Synthesis and characterization of Eu-doped hydroxyapatite through a microwave assisted microemulsion process

Europium doped hydroxyapatite (Eu:HAp) nanosized particles with multiform morphologies have been successfully prepared via a simple microemulsion-mediated process assisted with microwave heating. The physicochemical properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra, and the kinetic decays, respectively. The results reveal that the obtained Eu:HAp particles are well assigned to the hexagonal lattice structure of the hydroxyapatite phase. Additionally, it is found that samples exhibit uniform morphologies which can be controlled by altering the pH values. Furthermore, the samples show the characteristic ⁵D₀–⁷F_1–4 emission lines of Eu³⁺ excited by UV radiation.     

Uniform and size-tunable mesoporous silica with fibrous morphology for drug delivery

A family of mesoporous silica microspheres with fibrous morphology and different particle sizes ranging from about 400 to 900 nm has been successfully synthesized through a facile self-assembly process. The structural, morphological, and textural properties of the samples were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), N(2) adsorption/desorption, and thermal gravimetry (TG). The results reveal that this silica-based mesoporous material exhibits excellent physical properties, including a fibrous spherical morphology, good thermal stability, large pore volume, high specific surface area and narrow size distribution. Additionally, the size and textural properties can be tuned by altering the silica precursor/template molar ratio. The formation and the self-assembly evolution process have also been proposed. The obtained materials were further used as a drug delivery carrier to investigate the in vitro drug release properties using doxorubicin (DOX) as a representative model drug. It was found that this kind of silica exhibits good biocompatibility and obvious sustained drug release properties, suggesting its potential application in biological fields.