中空纤维膜基萃取稀土的研究：中空纤维膜基萃取Ce~(4+), Th~(4+)和RE~(3+)及其传质动力学

本文用中空纤维膜基萃取法研究了铈（IV）、钍和 RE（III）的膜基萃取；铈（IV）与 RE（III）、钍和 RE（III）的膜基萃取分离；铈（IV）与 RE（III）的界面化学反应动力学；膜基萃取中的流体动力学；萃取操作中乳化发生的机理；测定了中空纤维膜的孔率和孔径。在铈（IV）、钍和 RE（III）的膜基萃取过程中，研究了水相流量、油相流量、原料液中硫酸浓度、萃取剂 N1923浓度和水相溶质浓度对基于水相总传质系数的影响。钍的总传质系数受水相流量影响较大，不受油相流量影响，从而提出水相扩散层控制的膜基萃取传质机理；铈（IV）的传质系数受水相流量影响，油相流量影响较小，主要为水相扩散层控制的传质机理；RE（III）的传质系数受水相和油相的影响都比较小，为膜内传质过程的传质机理。酸浓度对钍和铈（IV）传质系数影响较小，是由于酸浓度影响分配系数，而对于水相扩散控制的传质过程，水相分传质系数与分配系数无关；酸浓度对 RE（III）的影响，是由于膜内传质阻力与分配系数在关；N1923 对 RE（III）萃取传质系数的影响进一步证明膜内过程控制的传质机理，同时对数曲线的斜率大于1 也说明界面反应为一复杂过程；水相溶质浓度不影响基于水相的总传质系数，进一步证实了传质速度与初始浓度无关，也从一个侧面反应了膜基萃取实验有较好的重复性。实验研究的结果，对铈（IV）的膜基萃取选择油相组成为 10%N1923+4%异辛醇+正庚烷（或煤油），水相酸浓度为 1～2mol/L，水相和油相流量可以在较大的范围内选择；钍的膜基萃取条件相似，只是油组成中萃取剂浓度为 1%N1923。在流体动力学部分，通过作用力分析，利用能量守恒原理，推导出了膜基萃取操作中的雷诺数，建立了层流流动模型；腔内外流体流速的径向分布模型和平均流速的计算式；腔内外压力沿管长度分布的数学模型，并得到了两相流体的压力差计算式。流体的动力学分析对于研究乳化发生的机理、传质的数学模型和扩散层厚度等皆有理论价值。通过流体动力学理论，结合膜破裂压和界面张力的实验方法研究了乳化发生的机理。水相进入有机相的乳化，对于非同级萃取，外压作用是乳化的主要原因，提出了类似于重力液滴形成的乳化模型；对于有机相进入水相的乳化，亲油膜的表面易形成油膜及界面张力形成的附加压力是乳化的基本原因，而随着有机相内溶质浓度增加界面张力降低使乳化在萃取操作的后期较易发生。膜破裂压和界面张力的研究方法使乳化的研究变得可以进行实验测定，这对于膜材的选择是很有价值的。界面反应动力学采用了上升单滴法，这种方法一般具有实验重复性较差的缺点。通过实验发现，影响重复性的因素主要是单滴形成速率的稳定性、聚结界面处油水界面位置的恒定和扩散传质的消除等。我们采用盘管式油加液管的设计，比较简单地解决了单滴形成速率稳定的问题，油水界面恒定是一个技术性问题，在实验中得到了较好的解决，通过传质时间与控制聚结界面的面积解决了消除扩散传质的难题。本论文的创新之处有如下几个方面：1．根据氟碳铈矿中钍、铈（IV）与稀土（III）分离的总目标，首次实现了伯胺 N1923对上述离子的中空纤维膜基萃取，提出了利用动力学差异的新型分离模式；2．对流量改变对传质系数的影响，所有文献报道的流量范围都没有达到流量增加使传质系数减小，而这一较高的流量揭示了油水界面随压力增加向膜内移动的事实，这对防止乳化时的压力控制是非常重要的。流量对扩散层厚度影响是对传质系数影响的主要原因，而混流的影响是次要的因素；3．铈（IV）和 RE（III）、钍和 RE（III）的分离表明，分离系数远远大于由总传质系数预计的结果，从而提出了动力学竞争萃取分离的机理；4．膜破裂压的测定方法是一个创新的设计。这种方法对于膜材选择和萃取时操作压力的控制是非常重要的。在现有文献中，都是直接在膜萃取操作时测定水相中的游离油或油相中游离水的体积的方法进行研究，这即不能研究乳化的机理，也不能测定准确的乳化时间。因此膜破裂压测定为乳化过程提供了一个新的研究方法；5．乳化机理的研究得到了较新的结论，尤其对于油相进入水相的乳化机理，较好地解释了在水相有超压存在下油相漏液的原因；6．界面反应动力学实验装置中盘管式油相加样解决了油滴形成稳定性的问题，提高了实验测定的可靠性的重复性。

1.3μm Si-Based MOEMS Optical Tunable Filter with a Tuning Range of 90nm

Optical filters capable of single control parameter-based wide tuning are implemented and studied. A prototype surface micromachined 1.3μm Si-based MOEMS (micro-opto-electro-mechanical-systems) tunable filter exhibits a continuous and large tuning range of 90 nm at 50 V tuning voltage. The filter can be integrated with Si-based photodetector in a low-cost component for coarse wavelength division multiplexing systems operating in the 1.3μm band.

Summer monsoon intensity controls C-4/C-3 plant abundance during the last 35 ka in the Chinese Loess Plateau: Carbon isotope evidence from bulk organic matter and individual leaf waxes

IEECAS SKLLQG

Effect of the nucleating agent 1,3 : 2,4-di(3,4-dimethylbenzylidene) sorbitol on the gamma phase content of propylene/ethylene copolymer

The influence of the concentration of a nucleating agent (NA), namely 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol (DMDBS), on the gamma phase content in a propylene/ethylene copolymer was investigated by means of Differential Scanning Calorimetry (DSC), Wide-Angle X-ray Diffraction (WAXD), Small- Angle X-ray Scatter (SAXS) and Polarized Optical Microscopy (POM).

Luminescent supramolecular microstructures containing Ru(bpy)(3)(2+): Solution-based self-assembly preparation and solid-state electrochemiluminescence detection application

In this correspondence, we report on the first preparation of novel, robust Ru(bpy)(3)(2+)-containing supramolecular microstructures via a solution-based self-assembly strategy, carried out by directly mixing H2PtCl6 and Ru(bpy)(3)Cl-2 aqueous solutions at room temperature. It reveals that both the molar ratio and concentration of reactants have a heavy influence on the morphologies of such microstructures. The electrochemical behavior of the Ru(bpy)(3)(2+) components contained in the solid film of the microstructures formed on the electrode surface is also studied and found to exhibit a diffusion-controlled voltammetric feature. Most importantly, such microstructures exhibit excellent electrochemiluminescence (ECL) behaviors and therefore hold great promise as new luminescent materials for solid-state ECL detection in capillary electrophoresis (CE) or CE microchip.

Encapsulation and luminescence of the nanostructured supramolecular material [Eu(Phen)(4)](NO3)(3)/(CH3)(3)Si-MCM-41

The nanostructured material (NSM) of pure silica MCM-41 molecular sieve was synthesized with tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethylammonium bromide (CTMABr) as the template under supersonic wave condition. Then NSM of (CH3)(3)Si-MCM-41 was obtained by introducing trimethylsilyl to MCM-41. (CH3)(3)Si-MCM-41 showed the similar TEM and XRD photographs with the normal crystal of MCM-41 and the diameter of the NSM crystallites with a hexagon shape is of about 10-40 nm. The dispersivity of (CH3)(3)Si-MCM-41 prevails over the NSM of MCM-41 as its hydrophobicity. The fluorescent intensity of (CH3)(3)Si-MCM-41 is 3.4 times as that of the MCM-41. The luminescent functional supramolecular nanostructured material was prepared in EtOH, and characterized by TEM, HRTEM, XRD, TG, IR, and elemental analysis. The results showed that the [Eu(Phen)(4)](NO3)(3) had entered into the channels of nanosized mesoporous sieve of (CH3)(3)Si-MCM-41, forming discrete centers of luminescence. The energy transferring of the host to guest, superficial effect of NSM, quanta tunnel effect, and discrete luminescent center result in the fluorescent intensity of the supramolecule enhancement.

用3种方法合成Y_3Al_5O_(12)∶RE~(3+)(RE=Eu,Dy)发光粉的对比研究

以金属硝酸盐为反应原料 ,分别采用柠檬酸 凝胶法、共沉淀法和固相法制备了YAG和YAG∶RE3+ (RE =Eu ,Dy) (1% ,摩尔分数 )发光粉 ,并通过XRD ,TG DTA和发光光谱对样品进行了表征。柠檬酸 凝胶法、共沉淀法和固相法制备的YAG和YAG∶Eu的晶相形成温度分别是 80 0和 90 0℃。Eu3+ 在非晶态和晶态YAG中其激发和发射光谱有明显差异 ,在一定温度范围内 ,发光强度随烧结温度的升高而增强。由于碳杂质的存在 ,90 0和 10 0 0℃下柠檬酸 凝胶法制备样品的发射强度较其他两种方法低。

Gas permeation properties of copolyimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride

A series of aromatic copolyimides was prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride (6FDA) with 3,3'-dimethyl-4,4'-methylene dianiline (DMMDA) by a chemical imidization. The gas permeability coefficients of the copolyimides to H-2, CO2, O-2, N-2 and CH4 were measured under 7 atm. pressure. The fractional free volume of 6FDA-DMMDA is larger than that of HQDPA-DMMDA, while the chain segmental mobility of 6FDA-DMMDA is lower than that of HQDPA-DMMDA. The gas permeability of 6FDA-DMMDA is much higher than that of HQDPA-DMMDA but the permselectivity of 6FDA-DMMDA for H-2, CO2, O-2, N-2 over CH4 is lower than that of HQDPA-DMMDA. The experimental values of the gas permeability coefficients of the copolyimides are in satisfactory agreement with the values estimated from the gas permeability coefficients of the constituent homopolyimides and their weight fractions.

Gas separation properties of aromatic polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 3,5-diaminobenzic acid or its esters

The gas transport properties of a series polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with 1,3-phenylenediamine or 3,5-diaminobenzic acid (DBA) or its esters are reported. The effects of carboxylic group (-COOH) and carboxylic ether groups (-COOR), at five positions of 1,3-phenylenediamine moiety, on H-2, CO2, O-2, and N-2 permeability, diffusivity, and solubility of the polyetherimides were investigated. The gas permeability, diffusion, and solubility coefficients of the polyetherimides containing COOR are bigger than those of HQDPA-PDA, but the ideal separation factors and ideal diffusivity selectivity factors are much smaller than that of HQDPA-PDA because COOR decreases chain segmental packing efficiency and increases chain segmental mobility. The permeability coefficients of HQDPA-DBA to H-2, CO2, and O-2 are bigger than those of HQDPA-PDA; the ideal separation factors for gas pairs H-2/N-2, CO2/N-2, and O-2/N-2 are also much bigger than those of HQDPA-PDA. Both the diffusion coefficients of CO2 and O-2 and the ideal diffusivity selectivity factors for CO2/N-2 and O-2/N-2 are bigger than those of HQDPA-PDA because COOH decreases both chain segmental packing efficiency and chain segmental mobility. The copolyimides, which were prepared from 3,5-diaminobenzic acid and 3,5-diaminobenzic esters, have both high permeability and high permselectivity. (C) 1997 John Wiley & Sons, Inc.

1,4-二丙氧基-2,3-二氰基萘的合成

以1，4－萘醌为原料，经溴化、氰化、烷基化合成了1，4－二丙氧基－2，3－二氰基萘，用SiemensP4四圆衍射仪测得了晶体结构。合成方法简便，反应时间短，产率高。

1,4-二丙氧基-2,3二氰基萘的晶体结构

用 Siemens P4四圆衍射仪,测得了1,4-二丙氧基-2,3-二氰基萘的晶体结构。晶体属单斜晶系,空间群为 C2/C。晶格参数 a=14.987(3)A,b=10.527(2),c=11.755(2),β=118.98°(3),晶胞体积 V=1622.4(6)3,Z=4,Dc=1.205Kg/m~3,μ(MoK_α)=0.079mm~(-1),F(000)=624,T=293(2)K_o晶体结构应用直接法,解出最后的偏离因子 R=0.0554[1425个Ⅰ≥2σ(Ⅰ)衍射点]。结构分析表明,萘环的1,4和2,3位碳原子上的氢原子分别被丙氧基和氰基所取代,由于取代基的引入使萘环的结构有所改变。

Structure/permeability and permselectivity relationship of polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride .2.

Gas permeability coefficients of a series of aromatic polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) with various aromatic diamines, to H-2, O-2 and N-2 have been measured under 7 atm and at the temperature range 30-100 degrees C. A significant change in the permeability and permselectivity resulting from the systematic variation in chemical structure of the polyetherimides was found. Among the polyetherimides, that were prepared from phenylenediamine and methyl substituted phenylenediamines, the increase of permeability is accompanied by a decrease of permselectivity. The polyetherimides that were prepared from 3,5-diaminobenzoic esters have lower permselectivity than the others. However, the polyetherimide from 3,5-diaminobenzoic acid possesses much higher permselectivity than the others due to cross-linking. Copyright (C) 1996 Elsevier Science Ltd

SYNTHESIS, SOLUTION DYNAMICS AND X-RAY CRYSTAL-STRUCTURES OF NEODYMIUM-YLIDE COMPLEXES, [(C(5)H(4)R)(3)NDCH2P(ME)PH(2)] (R=H, BU(T))

The interaction of [(C(5)H(4)R)(2)NdCl.2LiCl] (R = H, Bu(t)) with one equivalent of Li[(CH2)(CH2)PPh(2)] in refluxing tetrahydrofuran gave the purplish-blue complex [(C(5)H(4)R)(3)NdCH2P(Me)Ph(2)] in 50% yield. The compounds have been fully characterized by analytical, spectroscopic and X-ray diffraction methods. Variable temperature P-31{H-1} NMR spectroscopy indicated the existence of the following equilibrium: [(C(5)H(4)R)(3)NdCH2P(Me)Ph(2)] + THF reversible arrow (C(5)H(4)R)(3)Nd(THF) + CH2=P(Me)Ph(2). At room temperature, the exchange between the coordinated and free ylide ligand is slow on the NMR time scale.