分形基底上逾渗薄膜系统的三次谐波系数

本文首次研究了沉积在具有无规分形结构的a—Al_2O_3陶瓷断面上的Au逾渗薄膜系统的三次谐波系数和临界电流的关系.     

介观系统普适电导涨落的Fokker-Planck方程研究

利用一维介观系统的随机矩阵本征值分布函数的严格表达式,对闪粒噪声功率谱和无序NS结的普适电导涨落进行了计算,得出的严格结果如下:VarG_f=(1/2)×46/2835和VarG_(NS)=32(1/15-6/π~4).     

步进累加方法的实践

本文由理论与实验证明步进累加方法本质上是一种狭带的带通滤波的选择接收方法。其线型为类sinc函数。累加的结果与累加次数有关。对单脉冲后步进累加在一定次数以后即趋近饱和。对类回波的接收则出现极大值。只有在弱耦合体系中且offset选择在化学位移处才能得到所谓化学位移滤波。最后讨论实验条件及应用例子。     

SmP5O14晶体中Sm3+离子的能级和晶场参数

本文利用光谱方法测定了SmP5O14晶体中Sm3+离子的能级,通过拟合定出晶场参数,利用这些参数所计算的能级和实验能级符合得很好。     

Full-potential LMTO study on the electronic structure of heavy-fermion compound LiV2O4

The electronic structure of heavy fermion compound LiV₂O₄ has been calculated using a self-consistent full-potential LMTO method. The results show that the conduction bands in this compound are formed from V 3 d states with a bandwidth of 2.5 eV. The symmetric characteristics of conduction bands are of t_2g in principle. The energy gap between conduction bands and fully occupied oxygen 2p bands is 1.9 eV. The band dispersions near Fermi energy display complicated structures. Furthermore, the N( E_F) and y_cal are 11.1 (states/eV/f.u.) and 26.7 mJ/mol.K₂ determined numerically by LDA calculation, respectively. It is insufficient to clarify the origin of local moment in LiV₂O₄ from plain LDA calculations. In addition to the above LDA calculation, we also found a LSDA solution of LiV₂O₄ that is lower in total energy than that of LDA calculation. Similarly, LSDA + GGA calculation yields almost the identical result as that in LSDA. We conclude that the mechanism responsible for heavy fermion properties in LiV₂O₄ might be somewhat different from the plain Kondo mechanism in conventional 4f and 5f heavy fermion compounds and perhaps the quantum transition might play an adequate role in heavy-ferrnion behaviors in LiV₂O₄.     

气氛对铁电Pb(Zr_(0.52)Ti_(0.48)O_3薄膜特性的影响

本文着重研究了气氛对薄膜结晶性能、铁电性能的影响.结果发现,气体浓度对材料的结晶性以及铁电性能都有明显的影响.当Ar/O_2(mol)为2时,Pb(Zr_(0.52)Ti_(0.48))O_3薄膜为单相钙钛矿结构,而且所制得的薄膜的剩余极化P_r、饱和极化P_s以及介电常数最大.     

血清中胆汁酸的高效液相色谱荧光测定及质谱鉴定

在Hypersil C18色谱柱上，利用新型荧光试剂1，2-苯并-3，4-二氢咔唑-9-乙基对甲苯磺酸酯（BDETS）作柱前衍生化试剂，采用梯度洗脱对10种胆汁酸（BAs）荧光衍生物进行了优化分离。95℃下在二甲基亚砜溶剂中以柠檬酸钾作催化剂，衍生反应30min后获得稳定的荧光产物，衍生反应完全。激发和发射波长分别为λex=333nm，λem=390nm。采用大气压化学电离源（APCI）正离子模式，实现了血清中胆汁酸的定性和定量测定。线性回归系数均在0.9996以上，线性范围宽，检出限为12．94—21．94fmol。     

锂离子电池非水电解质中Li迁移特性

电解质是锂离子电池的重要组成部分之一，其中Li＋的迁移特性对电池性能具有显著影响。本文综述了用于锂离子电池的凝胶、聚合物和非水液态电解质中Li+迁移特性的研究进展，分析了影响Li＋迁移的主要因素，并提出了进一步的研究重点和新的研究方法。     

稀土元素掺杂对LiMn2O4正极材料改性的研究进展

尖晶石LiMn2O4作为高能锂离子二次电池的正极材料,其原料资源丰富、生产工艺简单、环境污染小、可回收利用,成为近年来人们研究的热点,被公认为最有潜力取代LiCoO2的正极材料之一.但是它的性能还不尽如人意,例如在循环及存放的过程中会出现容量衰减,高温情况下尤为严重.为了提高LiMn2O4正极材料的电化学性能,国内外研究者尝试了多种方法,例如元素掺杂、表面包覆、工艺改进等,其中掺杂金属元素已经被证明是最佳途径.结合作者所在实验室的工作,对稀土元素掺杂改变尖晶石LiMn2O4正极材料电化学性能的研究进行了综述.     

Coal characterization by on-line pyrolysis-field ionization mass spectrometry

Summary Pyrolysis-field ionization mass spectrometry (Py-FIMS) was used for the first time to directly characterize Chinese coals and their extracts. The summed mass spectra (about 30 magnetic scans) of four coal samples and the dimethylformamide extracts of two very different coals were registered between 50° and 750°C using linear heating in high vacuum (10^–3 Pa) and approximately 6 min temperature rise time. Utilizing temperature-programmed pyrolysis and FI as soft ionization mode, the spectra displayed almost exclusively molecular ions of the evolved products. The thermograms, i.e. the intensities of the total ion current and selected ions were plotted versus the scan number, heating time and temperature. In general, two maxima in these thermograms were observed, which were different for the coals and reflected their carbon/hydrogen content. Comparing the mass spectra of the low temperature part (first maximum) with summed spectra of the extracts shows an interesting similarity. In contrast, the high temperature part (second maximum) indicates the products of thermo-degradation. The applied method is a fast and convenient tool for the characterization of evolved volatiles and thermal degradation products of coals and coal extracts.

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Kennzeichnung von Kohlen mit direkter Pyrolyse und Feldionisations-Massenspektrometrie