QuEChERS/高效液相色谱测定食品中17种邻苯二甲酸酯

建立了同时检测食品中17种邻苯二甲酸酯类化合物的QuEChERS/高效液相色谱分析方法.样品经乙腈提取,采用含50 mg PSA和150 mg MgSO4填料的净化管进行净化,分析液经C18柱分离,乙腈-水为流动相梯度洗脱,流速1.0 mL/min,紫外检测波长224 nm.在优化色谱条件下,DINP在0.5～10 m...     

毛细管电泳-激光诱导荧光检测法分析胃癌组织及癌旁正常组织蛋白质的差异性

胃癌是临床常见的恶性肿瘤之一。近年来寻找肿瘤相关特异蛋白质是蛋白质组学研究的热点。本文通过考察毛细管动态涂层方法、筛分介质聚环氧乙烷(PEO)的浓度、缓冲液的pH值、分离电压、温度及荧光染料对分离效果的影响,建立了毛细管电泳-激光诱导荧光法分离胃癌组织及癌旁正常组织蛋白质的方法;通过分离检测,获得两者的蛋白质指纹图谱。经分析,两者的指纹图谱相似度达到0.8以上,差异蛋白质分子质量集中在50000~100000 Da之间,提示某些小分子蛋白质可能是和肿瘤发生相关的特异蛋白质,从而缩小了特异性分子标记物的筛选范围。病理组织学分型及蛋白质电泳峰数目的统计结果验证了该方法的可靠性。该方法具有临床应用的潜力。     

基于新能源材料与器件专业的理论教学*——绝对电位和相对电位

为培养新能源材料与器件专业学生的科研与创新能力,以新能源热点前沿“电化学还原CO₂”作为切入点,引导学生明晰绝对电位和相对电位,掌握参比电极,揭示实际电位的意义,探索将基础理论教学与科研前沿相结合。融合专业研究前沿和基础理论能激发学生的专业兴趣,让学生重视科学严谨性和前沿性,为培养能用于新能源方向、具有综合素质的专门人才奠定基础。     

高效毛细管电泳用于以聚环氧乙烷为筛分介质分离DNA的机理研究

用毛细管电泳以聚环氧乙烷(PEO)为筛分介质对pUC19DNA/Msp Ⅰ(HpaⅡ)Marker中的12条DNA片段进行了分离,并尝试用Ogston模型、爬行模型以及线性模型对分离机理进行研究,最终发现26～147bp的小片段,在低电场强度时能很好地符合Ogston模型理论,而190～501bp中等长度的DNA片段电泳迁移率与其尺寸间存在很好的负相关的线性关系,为此,提出一种新的线性模型来进行解释.此外,还探讨了PEO的浓度和电场强度对分离的影响.其结论可更好地从理论上指导对中小片段DNA的分离,对肿瘤基因突变点的分析和PCR扩增产物的分离分析具有重要的意义.     

Simulation of cross-correlation method for temporal characterization of VUV free-electron-lasers

The cross-correlation method for temporal characterization is investigated using simulations of the two- color above threshold ionization （ATI） on He induced by a vacuum ultraviolet （VUV） free-electron laser （FEL） in the presence of an infrared （IR） field. Non-linear dependencies of the sideband structure pro- duced in the two-color ATI process are expressed as a function of IR laser intensity by considering the spatial distributions and temporal jitter of both lasers. The temporal properties of the FEL pulse can be characterized accurately using the cross-correlation method at a low IR laser intensity of ~3~101~ W/cm2 but with low cross-correlation signals. When the dynamic range of sidebands is increased to high IR intensity, the accuracy of the cross-correlation method becomes crucially dependent on the actual non- linear index. An approach of determining this index is proposed here to improve the accuracy of temporal characterizations.     

Epoxy replication of hard X-ray supermirrors

The direct replication of W/Si supermirrors is investigated systematically. W/Si supermirrors are fabricated by direct current(DC) magnetron sputtering technology. After deposition,the supermirrors are replicated from the supersmooth mandrels onto ordinary float glass substrates by epoxy replication technique. The properties of the supermirrors before and after the replication are characterized by grazing incidence X-ray reflectometry(GIXR) measurement and atomic force microscope(AFM) . The results show that before and after replication,the multilayer structures are almost the same and that the surface roughness is 0.240 and 0.217 nm,respectively,which are close to that of the mandrel. It is demonstrated that the W/Si supermirrors are successfully replicated from the mandrel with good performance.     

氪原子价壳层的广义振子强度研究

在入射电子能量2.5 keV、角度1°- 8°条件下测量了氪的价壳层偶极允许跃迁4p6(1S0) → 4p55s[3/2]1, 4p55s′[1/2]1, 以及偶极禁戒跃迁4p6(1S0) → 4p55p的绝对广义振子强度, 并与前人的实验和理论结果进行了比较.     

Optically Forbidden Excitations of 3s Electron of Argon by Fast Electron Impact

The electron energy loss spectrum of argon in the energy region of 24.5—30.5 eV was measured at 2.5 ke V impact energy. The line profile parameters of the optically forbidden excitations of 3s^-1 ns (n = 4-6) and 3s^-1 nd (n = 3-7) of argon, i.e., Er,Г,q and μ were determined.     

Optical Oscillator Strengths of Hydrogen Bromide in the 4.5-20 eV Excitation Energy Region

The absolute optical oscillator strength density spectrum of HBr in the valence shell energy region of 4.5-20eV has been determined by a high-resolution fast electron energy loss spectrometer. The optical oscillator strengths for the broad a^3∏ A^1∏ dissociation peak and the discrete transitions orb ^3∏1 (v′=0) and C^1∏(v′=0,1,2) are     

Kr原子4s自电离区和3d内壳层光学振子强度研究

用高分辨快电子能量损失谱方法研究了Kr原子4s内价壳层自电离区的光学振子强度, 说明了以前几家实验存在差异的原因, 并首次得到了3d内壳层激发的绝对光学振子强度.