地面附近的高空核爆电磁脉冲环境

 主要研究在高空核爆的双指数类型电磁脉冲平面波入射时，地面附近的电磁脉冲环境。计算给出了在不同入射波状态，不同地表介质电气特性和距地面不同高度等条件下的电磁脉冲环境参数，归纳了一些规律性认识。结果显示：地面附近的电场会随距地面高度的不同而发生显著的变化，对于水平场分量，其反射场总是试图抵消入射场，而对于垂直场分量，其反射场叠加在入射场上，使得地面附近的垂直场强幅值一般大于入射波场强幅值；当入射波仰角增大时，合成电场波形的脉冲宽度会变宽；地表介质的电气特性参数不同也会对地面附近电场的波形和幅值造成一定的影响。     

Enantiospecific synthesis of isomers of AES, a new environmentally friendly chelating agent

Three four-step enantiospecific syntheses of different diastereomers of AES, a new biodegradable chelating agent, are described. The stereocenters in each of the isomers are accessible from l- and d-malic and aspartic acids.     

电热蒸发进样微波等离子体炬原子发射光谱法中共存元素的影响

本文考察了以微波等离子体炬（MPT）为光源，电热钽丝环进样时，溶液中共存元素对发射信号的影响。     

Modification of the cation exchange resin properties by impregnation in polyethyleneimine solutions: application to the separation of metallic ions

A commercial cation exchange resin Amberlite 200 has been modified after immersion in solutions of polyethyleneimine (PEI). The kinetic of fixation of the metallic ions have been determined. The modification of the surface of the resin deals with a change in the order of the affinities of the resins towards cations. The retention is the function of the formation and the stability of the complex. The conditions of modification (pH, PEI concentration and time of immersion) have been examined and the modification was confirmed by the determination of the exchange capacities, the distribution coefficient (P) and the selectivity factors (S). The obtained results revealed the effect of PEI on the exchange properties of the resin. The pH range selected (6-8) permitted a good adherence of PEI onto the resin surface. The quantity of the adsorbed PEI was increased by raising the initial concentration and the immersion period. The exchange capacity for copper ion passed from 2.6 mmol g⁻¹, in the case of unmodified resin, to 3.9 mmol g⁻¹ for the modified one.     

Determination of vanadium, molybdenum and tungsten in complex matrix samples by chelation ion chromatography and on-line detection with inductively coupled plasma mass spectrometry

In this work, two kinds of chelating resin, bis(2-aminoethylthio)methylated resin (BAETM) and γ-aminobutyrohydroxamate resin (γ-ABHX) were synthesized. Of these, the former has a hydrophobic skeleton, and the latter a hydrophilic skeleton. The functionalities of each were 0.91 and 2.21 mmol g⁻¹, respectively. The chelating behavior of these resins towards vanadium, molybdenum and tungsten as a function of pH was studied. To perform trace metals analysis in complex matrices, a hyphenated method-chelation ion chromatography (CIC) coupled on-line detection with inductively coupled plasma mass spectrometry (ICP-MS) was developed. With a BAETM resin column (5×0.4 cm i.d.) as the separator, a sample volume of 20 μl, nitric acid (pH 1.5) as the eluent and a flow rate of 1 ml min⁻¹, the detection limits for the determination of vanadium, molybdenum and tungsten were lower than 0.05 ng ml⁻¹and the linear ranges were up to 100 ng ml⁻¹ for each element. By increasing the injected sample volume to 250 μl, the resin concentrator improved the detection limit to 0.01 ng ml⁻¹. For the determination of these elements (5 ng ml⁻¹ for each) spiked in artificial sea water samples, γ-ABHX resin column (3×0.6 cm i.d.) demonstrated well resolved peak separation between the analytes and the matrix elements—calcium and magnesium, by using sodium nitrate (10 ml, 10⁻⁴ M) as the eliminator.     

溶剂蒸气对聚对苯二甲酸乙二酯作用的差示扫描量热研究

用差示扫描量热(DSC)研究了几种有机溶剂蒸气对聚对苯二甲酸乙二酯(PET)的作用,表明可分为反应性的和非反应性的两种。同时,对于非反应性的作用,依冷结晶峰面积的变化,又可分为三种类型:冷结晶峰面积不变,经诱导期后下降,无诱导期而迅速下降。双冷结晶峰现象在一些非反应性溶剂处理过的PET试样的DSC曲线也观察到。     

以硫醚为主链的螯合树脂研究Ⅰ.4-氨基安替吡啉树脂和乙基原磺酸基树脂的合成及吸附性能

聚环硫氯丙烷或环硫氯丙烷与环氧氯丙烷共聚物，在少量二乙烯三胺存在下制得交联预聚物，将交联预聚物与4－氨基安替吡啉（4AAP）或乙基原磺酸钾（PEA）反应，制得四种侧链带氨基安替吡啉，乙基原碘酸基的新型螯合树脂。它们对贵金属具有优良的吸附性能和高的吸附选择性。并通过X－射线光电子能谱初步探讨了树脂对金属离子的螯合作用。     

Effects of fluorine atoms on the optical nonlinear response of stilbene derivatives

The effect of fluorine atoms on the second-order optical nonlinear response of 4-nitro-4′-methoxy-trans-stilbene and polyene derivatives containing up to three double bonds (n=1, 2, 3) has been investigated within a semiempirical context (PM3 Hamiltonian). Experimental data reported in literature indicate a β_vec(SHG) value of 34, 47 and 76 (×10⁻³⁰ esu) for n=1, 2, 3, respectively, at 0.65 eV in CHCl₃ solutions. Our calculations show that fluorinating the nitrophenyl group the β_vec(SHG) is doubled. Further increase in the second-order nonlinear response can be obtained fluorinating the CC bond linkers between the aromatic moieties.Besides, the effect of different donor-acceptor pairs has been studied and the results interpreted in the two-state model context.Some results concerning the third-harmonic generation (THG), γ (THG), are presented, and a possible interpretation proposed.     

On-line preconcentration using dual mini-columns for the speciation of chromium(III) and chromium(VI) and its application to water samples as studied by inductively coupled plasma-atomic emission spectrometry

On-line preconcentration system for the selective, sensitive and simultaneous determination of chromium species was investigated. Dual mini-columns containing chelating resin were utilized for the speciation and preconcentration of Cr(III) and Cr(VI) in water samples. In this system, Cr(III) was collected on first column packed with iminodiacetate resin. Cr(VI) in the effluent from the first column was reduced to Cr(III), which was collected on the second column packed with iminodiacetate resin. Hydroxyammonium chloride was examined as a potential reducing agent for Cr(VI) to Cr(III).The effects of pH, sample flow rate, column length, and interfering ions on the recoveries of Cr(III) were carefully studied. Five millilitres of a sample solution was introduced into the system. The collected species were then sequentially washed by 1 M ammonium acetate, eluted by 2 M nitric acid and measured by ICP-AES. The detection limit for Cr(III) and Cr(VI) was 0.08 and 0.15 μg l⁻¹, respectively. The total analysis time was about 9.4 min.The developed method was successfully applied to the speciation of chromium in river, tap water and wastewater samples with satisfied results.     

Isomerisierung bei der Komplexbildung von 3-Acetyl-tetramsäure: Struktur und magnetische Eigenschaften des CuII- und NiII-Komplexes von 2,7-Bis(1′, 5′, 5′-trimethylpyrrolidin-2′, 4′-dion-3′ -yl)-3, 6-diazaocta-2, 6-dien

Isomerization at the Complexation of 3-Acetyltetramic Acid: Structure and Magnetic Properties of the Cu^II- and Ni^II-Complex of 2,7-Bis (1′, 5′, 5′ -trimethylpyrrolidin-2′,4′ -dion-3′ -yl)-3,6-diazaocta-2,6-dien 2,7-Bis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -yl)-3,6-diazaoctadien formes Cu^II and Ni^II complexes with different constitutions (because of the Z/E isomerization). Results of X-ray analysis of N,N′ -ethylenbis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -acetiminato)nickel(II) 1 respectively -copper(II) 2 shows, that the complexing agent in 1 occurs in the E-form, whereas the ligand of the Cu^II complex forms the Z-form. Magnetic susceptibility and shift effects of the ¹³C-NMR signals point to a weak paramagnetism of the Ni^II complex. ESR-spectra are obtained from 2 only. Furthermore, the Cu^II complex reduces the relaxation times T₁ and T₂ of ¹H and ¹⁷O nuclei spins from water. From the temperature dependence of the shortening of the relaxation times an activation energy is calculated which describes the reorientation of the copper complex in the “water matrix”.