β-环糊精修饰的荧光金纳米簇的合成及其在细胞成像上的应用

通过一锅法水相合成出一种β-环糊精修饰的荧光金簇。该新型金簇具有红色荧光发射、长时间的分散稳定性和荧光稳定性。透射电镜观察其平均粒径为(1.40±0.32)nm。激光共聚焦显示金簇分散在细胞质中,荧光随金簇浓度增加而增强。细胞毒性实验证实该金簇具有良好的生物相容性。表面修饰的β-环糊精,也为金簇载药或者靶向功能化提供了更多可能性,从而进一步拓宽其在生物医学方面的应用。     

基于氢键诱导的纳米金比色传感器实时检测脂肪酶活性

以巯基乙酸甲酯(MT)修饰的纳米金(AuNPs)为探针,构建了比色生物传感器检测脂肪酶活性.在pH 6.5弱酸性条件下,脂肪酶水解MT-AuNPs上的酯键生成带负电荷的羧酸根;在pH 3.0的酸性条件下,探针间会产生强烈的氢键作用使AuNPs聚集,基于此可以检测脂肪酶活性.考察了温度、pH等因素对传感器响应信号的影响.MT-AuNPs溶液在650和520 nm处的吸光度比值A650/A520与脂肪酶活性大小在3.0×10-4 ～4.5 ×10-2 U/mL范围内呈现良好的线性关系,检出限为2.25×10-4 U/mL(S/N=3).测定了5种商品化脂肪酶的活性,实验结果与恒电位滴定法测定结果一致,证明本方法具有良好的实用性.     

氯参与的化学气相淀积金刚石的热力学分析

用非平衡热力学耦合模型研究了金刚石在ＣＨＣｌ体系中的生长，计算所得ＣＨＣｌ体系的金刚石生长的相图与大量实验结果符合良好．通过热力学分析讨论了氯的添加对提高金刚石薄膜生长速率及其质量的影响以及降低淀积温度的作用     

水流吸收型高能激光能量计溯源方法及其溯源体系研究

提出了一种利用电加热丝作为校准源的高能激光能量计校准方法,将水流从吸收腔前端导入至加热容器,在加热后流入吸收腔。通过精确计量水流吸收的热能并与能量计测量结果进行比较,达到对高能激光能量计校准的目的。研究表明校准系统的热交换模型与吸收腔内的热交换模型一致,均经历了储能和功率平衡两个阶段。水流及相变气体的散射效应对测量结果的影响较小,经过修正后可以忽略其影响。通过深入分析各个环节的测量不确定度表明,残留能量和流量变化对测量不确定度的影响最显著,增加水箱的容积可以有效降低残留能量对测量不确定度的影响。在对各个环节的影响修正后估算出系统的测量不确定度约为4.8%(k=2),被校高能激光能量计校准后的测量结果与其他类型的参考高能激光能量计进行比对,两者具有很好的一致性,修正因子仅为1.006,标准偏差为1.4%。     

Optimization of High-Order Harmonic by Genetic Algorithm for the Chirp and Phase of Few-Cycle Pulses

The brightness of a particular harmonic order is optimized for the chirp and initial phase of the laser pulse by genetic algorithm. The influences of the chirp and initial phase of the excitation pulse on the harmonic spectra are discussed in terms of the semi-classical model including the propagation effects. The results indicate that the harmonic intensity and cutoff have strong dependence on the chirp of the laser pulse, but slightly on its initial phase. The high-order harmonics can be enhanced by the optimal laser pulse and its cutoff can be tuned by optimization of the chirp and initial phase of the laser pulse.     

四角晶相HfO2(001)表面原子和电子结构研究

采用基于第一性原理的密度泛函理论研究了四角晶相二氧化铪(t-HfO₂)体相及 其(001)表面的原子几何与电子结构.理论计算结果表明，t-HfO₂(001)表面不会 产生重构现象.与体相电子结构相比, t-HfO₂(001)表面态密度明显高于体相态 密度.其次，表面原子的态密度更靠近费米能级(E_F)，价带往低能量处移动，并 有表面态产生.计算结果表明了t-HfO₂表面禁带宽度明显低于体相的禁带宽度. t-HfO₂(001)的表面态产生以及表面禁带宽度减小是由于Hf原子与O原子的配位 数减少，表面原子周围的环境发生变化而引起的. 关键词： 密度泛函理论 2(001)')" href="#">t-HfO₂(001) 表面电子结构     

应用氢谱发现微量天然产物中甾醇类化合物及其定量的初探

在研究黄海繁茂膜海绵的天然产物时，发现5β-CHOLESTAN-3β-OL在其体内大量存在；通过¹H NMR谱发现还有少量CHOLESTEROL的存在. 在GC-MS谱图中，并未分析得到CHOLESTEROL. 通过标准品5β-CHOLESTAN-3β-OL和CHOLESTEROL混合物的¹H NMR谱图，对难分离的甾类化合物用¹H NMR谱定量进行初探.     

聚乙炔的CH面外振动红外光谱研究

采用从头计算方法，计算了反式和顺式聚乙炔的氢原子在垂直于聚乙炔分子面方向振动的红外光谱，计算表明，Gibson等用红外吸收实验所测得的谱线的确是聚乙炔的CH面外振动产生的谱线，经100℃长时间加热后，顺式聚乙炔变为反式聚炔，但波数为740cm^-1的谱级仍保留5％的强度。     

Effect of N2 Plasma Annealing of Properties of Fluoring Doped Silicon Dioxide Films with Low Dielectric Constant for Ultra—Large—Scale Integrated Circuits

The influence of N2 plasma annealing on the properties of fluorine doped silicon oxide (SiOF) films is investigated.The stability of the Dielectric constant of SiOF film is remarkably improved by the N2 plasma annealing.After enduring a moisture absorption test for six hours in a chamber with 60% humidity at 50℃,the dielectric constant variation of the annealed SiOF films is only 1.5%,while the variation for those SiOF films without annealing is 15.5%.Fourier transform infrared spectroscopic results show that the absorption peaks of Si-OH and H-OH of SiOF films are reduced after the N2 plasma annealing because the annealing can wipe off some unstable Si-F2 bonds in SiOF films.These Unstable Si-F2 bonds are suitable to react with water,resulting in the degradation of SiOF film properties.Therefore,the N2 plasma annealing meliorates the properties of SiOF films with low dielectric constant.     

Band Structures of Metal-Oxide Capped Graphene： A First Principles Study

We perform a first-principles calculation based on density functional theory to investigate the interface between single layer graphene and metal oxides. Our study reveals that the monolayer graphene becomes semiconducting by single crystal SiO2 and Al2O3 contact, with energy gaps to - 0.9 and - 1.8 eV, respectively. We find the gap originates from the breakage of π bond integrity, whose extent is related to the interface atom configuration. We believe that our results highlight a promising direction for the feasibility to apply large scale graphene layers as building blocks in future electronics devices.