Cu2+、Pb2+在高岭土中的顺序竞争吸附动力学研究

本文以吸附动力学实验为基础,结合动力学模型对典型的重金属Cu2+ 、Pb2+在高岭土中的顺序竞争吸附动力学特性进行了深入的研究,重点考察了离子的初始浓度、两种重金属离子进入土壤的先后顺序及时间节点对吸附过程和结果的影响。结果表明：高岭土中存在两种类型的吸附位点;高岭土对同时竞争时两种重金属的吸附总量大于顺序竞争时的吸附总量,且进入高岭土的时间点对吸附结果也有很大的影响;此外伪一级动力学方程仅适用于反应的初始阶段,而伪二级动力学方程则可以较好的拟合整个竞争吸附过程。     

微波消解-石墨炉原子吸收光谱法测定植物染发剂中的铅镉铜

建立了微波消解-石墨炉原子吸收光谱法测定植物染发剂中重金属铅、镉和铜的方法.采用L9(34)正交设计讨论了固液比、消解剂体积比、消解时间和消解压力对样品消解效果的影响,最佳的消解条件:固液比(g/mL)为1∶12,HNO3/H2O2(V/V)为4∶1,消解时间为5min,消解压力1.5MPa.在最佳微波消解条件下,进行了精密度实验、回收率实验,相对标准偏差为1.05%~3.35%,回收率为96.67%~105.43%.微波消解法处理植物染发剂样品,试剂用量少、消解完全、快速、简便,而且测定结果的精密度、准确度较好.     

Flow injection system for the on-line preconcentration of Pb by cloud point extraction coupled to USN–ICP OES

A novel method for the determination of Pb by on-line cloud point extraction coupled to inductively coupled plasma optical emission spectrometry with ultrasonic nebulization (USN–ICP OES) is presented. The cloud point system was formed in the presence of non-ionic micelles of polyethyleneglycolmono-p-nonylphenylether (PONPE 7.5) and was retained in a minicolumn filled with particles of PTFE. Since the micelles of PONPE were able to extract Pb from the solutions, the use of a complexing reagent was not necessary. Afterwards, the surfactant-rich phase containing the analyte was removed from the minicolumn with nitric acid and introduced into the ultrasonic nebulizer. A total enhancement factor of 150 was obtained for a preconcentration time of 3.3 min, with respect to the direct determination of Pb by conventional ICP OES. The values of the detection (3σ) and quantification (10σ) limits for the preconcentration of 10 mL of sample solution were 0.09 µg L^{− 1} and 0.2 µg L^{− 1} respectively. The precision, expressed as the relative standard deviation (RSD), for 10 replicate determinations at 5.0 µg L^{− 1} Pb level was 6.0%. Verification of the accuracy was carried out by analysis of two certified reference materials (NIST SRM 1640e and VKI QC Metal LL1). The method was successfully applied to the determination of Pb in drinking water samples.     

锂铅合金释氚实验研究

由于锂铅合金因具有高增殖比、低活泼性和可能作为冷却剂的特点,被认为是最有潜力的能源堆包层氚增殖材料。在理论模型描述熔融锂铅合金氚释放行为的基础上,开展了中子辐照后Li₁₇Pb₈₃合金的离线氚释放实验。结果表明: 释放氚的化学形式99％以上为难溶于水的成分（HT或T2）; 氚滞留时间随载气中氢分压的增加而减小,氢分压达到1000 Pa后变为常数,且与实体积无关;氚释放速率对温度的依赖性符合Arrhenius定律。以此为基础得到的氚在熔融锂铅中的动力学参数结果,虽与文献值有差异,但同样证明了在633—973 K的范围内, 氚从液态锂铅到气相的整个释放过程中起决定作用的是氚在合金内的扩散和气\|液界面的多相反应重组。Lithium\|lead alloy is considered to be one of the most prominent tritium breeding materials for the fusion reactor blanket because of its high breeding ratio, and low reactivity and possible use as coolant. An out\|of\|pile experiment of tritium release from Li₁₇Pb₈₃ alloy was performed after neutron irradiation on the base of mathematical model to describe tritium release behavior from an eutectic lithium\|lead alloy. The results suggest that the dominant chemical form of the released tritium (>99%) was the water\| insoluble component (HT or T2). Tritium residence time decreased with increasing H₂pressure in carrier gas up to 1000 Pa, and above this concentration limit it became constant and not influenced by the plenum volume. The temperature dependence of the tritium release rate can be described by an Arrhenius law. Consequently, the present results on the kinetic parameters of tritium in molten Li₁₇Pb₈₃alloy are considered to be different from the values in literature, but it is the same that the overall release process is governed by the diffusion of tritium atoms in the Li₁₇Pb₈₃and by the heterogeneous reaction at the gas\|eutectic interface of the tritium atom recombination at temperatures from 633 to 973 K.     

Configuration interactions constrained by energy density functionals

A new method for constructing a Hamiltonian for configuration interaction calculations with constraints to energies of spherical configurations obtained with energy-density-functional (EDF) methods is presented. This results in a unified model that reproduced the EDF binding-energy in the limit of single-Slater determinants, but can also be used for obtaining energy spectra and correlation energies with renormalized nucleon–nucleon interactions. The three-body and/or density-dependent terms that are necessary for good nuclear saturation properties are contained in the EDF. Applications to binding-energies and spectra of nuclei in the region above ²⁰⁸Pb are given.     

锂辉石和铅锌矿基非晶质建材的性能

固体工业废渣的利用对于变废为宝、减小环境污染程度诸方面具有非常重要的意义，利用固体工业废渣制备新型建筑材料是废渣利用的重要发展方向．为此，以锂辉石和铅锌矿尾矿为主要原料，添加适宜的其他化工原料，采用传统熔体冷却方法而制得几种黄黑色花纹的建筑用材料．通过X射线衍射分析(XRD)和利用扫描电子显微镜照片（SEM）对获得的材料进行了物相和结构研究，并与天然石材的理化性能进行了比较．研究结果表明获得的几种材料均是非晶质的，结构中含有粒径大约为0.2μm的未完全熔化的SiO2或Al2O3颗粒，其理化性能及美学效果与天然石材可比，具有开发应用前景．     

Pyroelectric spectrum in Pb(Zr,Sn,Ti)O3 antiferroelectric-ferroelectric ceramics

The pyroelectric effect of phase transition induced with temperature in Nb-modified Pb(Zr,Sn,Ti)O₃ antiferroelectric-ferroelectric ceramics is studied. Experimental results reveal that the phase transitions are accompanied with marked pyroelectric peaks, there exists the close relation between the type of phase transition and the shape of pyroelectric peak. Because of the variations of phase transition, various pyroelectric spectra result. The pyroelectric spectrum can display the polarization effect and some inferior phase transitions with temperature variations, such as antiferroelectric AFE_A-AFE_B or ferroelectric FE_L-FE_H transition, which are not detected by the conventional dielectric measurement.     

1979-2007年中国造纸术发明者争议的回顾

造纸术是由东汉宦官蔡伦还是西汉工匠发明,是一个有争论的学术问题.1949-1979年两种观点争鸣是正常的学术现象.但自1979年轻工部造纸局行政干预以来,有关中国造纸术发明者的争议已经脱离正常讨论轨道.政府机构利用职权和行政资源推行官方观点,将蔡伦造纸说奉为“历史定论”,以“爱国与维护国家尊严”为名,树立学术禁区,打压不同意见,对出土西汉纸作歪曲事实的反检验和反断代,以政令方式对纸史争议作“最后裁决”.潘吉星作为参与这项纸史争议的见证人,揭示了这场争议中的某些真相.     

复合催干剂的研制

介绍了五种三元复合催干剂的制备及在醇酸清漆中的性能 ,结果表明该复合催干剂性能优异 ,可代替传统的钴锰铅钙锌五元体系 ,并简化工艺 ,降低成本 ,其中环保无铅化配方值得大力推广。     

Molecular and Supramolecular Structures of 1‐Phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H2L) and its Complexes with Diphenyllead(IV) Chloride and Acetate

Reaction of 1‐phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H₂L) with diphenyllead(IV) dichloride and acetate afforded the complexes [PbPh₂Cl₂(H₂L)₂] and [PbPh₂L]. The ligand and the complexes were characterized by elemental analyses, ¹H and ¹³C NMR spectroscopy and X‐ray crystallography. In the asymmetric unit of crystals of the ligand there are four independent molecules of H₂L and four molecules of water, which associate in the lattice as two independent sheets. The complex [PbPh₂Cl₂(H₂L)₂]·4MeOH has slightly distorted all‐trans octahedral geometry around the lead atom, and the fact that the ligand is S‐bound rather than O‐bound suggests that PbPh₂Cl₂ behaves as a “soft” Lewis acid. Hydrogen bonds involving NH groups, Cl atoms and MeOH molecules form a three‐dimensional supramolecular structure. In [PbPh₂L]·Me₂CO, the L^2? anion bridges between two metal centres, binding to one strongly via the N and S atoms and weakly via the O atom, and to the other via the O atom, thus creating polymeric chains along the b axis. The double deprotonation and metallation of H₂L induce significant changes in its configuration and lengthen the C‐S and C‐O bonds, suggesting an evolution of the dianion towards a thiol‐enol form.