Fabrication and Characterization of Ni Thin Films Using Direct-Current Magnetron Sputtering

Ni films are deposited by using ultra high vacuum dc magnetron sputtering onto silicon substrates at room temperature, and the high-quality and high-density films are prepared. The parameters, such as thickness, density and surface roughness, are obtained by using small-angle x-ray diffraction (XRD) analyses with the Marquardt gradient-expansion algorithm. The deposition rate is calculated and the Ni single layer can be fabricated precisely. Based on the fitting results, we can find that the surface roughness of the Ni films is about 0.7nm, the densities of Ni films are around 97% and the deposition rate is 0.26nm/s. The roughness of the surface is also characterized by using an atomic force microscope (AFM). The changing trend of the surface roughness in the simulation of XRD is in good agreement with the AFM measurement.     

含三个硬脂酰胺基的树枝状季铵盐的制备

由三羟甲基丙烷三丙烯酸酯(TMPTA)和乙二胺(EDA)直接进行M ichael加成反应,合成端基为3个NH2的树枝状大分子G(NH2)3,用硬脂酰氯将其端氨基进行酰胺化得到端基为3个硬脂酰基的树枝状大分子GS(R)3,产率为82.4%。GS(R)3进一步与碘甲烷反应,其分子中的3个仲氨基被季铵化,生成树枝状季铵盐GI(R)3,产率为82.0%。讨论了反应温度、反应时间和原料配比对GS(R)3和GI(R)3产率的影响,并用红外、核磁和元素分析对GS(R)3和GI(R)3的结构进行表征。     

Different Behaviors of ACE Inhibitor Tripeptide Ile-Ile-Pro in Aqueous and DMSO Solutions by All-Atom MD Simulations and 2D-NOESY Spectra

All-atom molecular dynamic simulations and 2D-NOESY spectra were used to study the conformations and hydrogen bonds of ACE inhibitory tripeptide Ile-Ile-Pro(IIP) in aqueous and DMSO solutions. RMSD, Dis, Rg and SASA were adopted to characterize the properties of tripeptide Ile-Ile-Pro in the MD simulations. Interestingly, the tripeptide molecule IIP exhibited different behaviors in aqueous and DMSO solutions. In aqueous solution, IIP was very flexible. The conformation could shift between extended and folded states very quickly. However,in DMSO solution, more folded conformations were observed. The interesting phenomena were proved by 2D-NOESY spectra.     

抗癌性吲哚喹唑啉衍生物的定量构效关系

用量子化学密度泛函理论(DFT)、分子力学(MM＋)及回归分析方法,对一系列抗癌性吲哚喹唑啉衍生物进行了定量构效关系(QSAR)的研究.通过回归分析,筛选了影响抗癌活性的主要因素,建立了定量构效关系方程.结果表明,化合物的最低未占据分子轨道(LUMO)与最高占据分子轨道(HOMO)之间的能量差(ΔεL-H)、分子的疏水性(lgP)以及环D上的总电荷(ΣQD)和环D上R1取代基的第一个原子的净电荷(QFR1)是影响化合物抗癌活性的主要因素.所得模型对化合物抗癌活性有较好的预测效果. 同时, 与ΔεL-H密切相关的LUMO轨道能量及共轭平面面积对药物的DNA-结合及其活性起着十分重要的作用,可通过选取具有较强的拉电子性质同时又能与本系列化合物的骨架形成更大共轭体系的取代基R1,设计抗癌活性较高的化合物.     

X射线Kirkpatrick-Baez显微镜用超反射镜的研制

 介绍了一种可应用于X射线Kirkpatrick-Baez（KB）显微镜的光学元件—X射线超反射镜。选用的W和B₄C作为镀膜材料，膜对数为20，采用单纯型调优的方法实现了X射线超反射镜设计，用磁控溅射的方法在Si基片上完成了W/B₄C X射线超反射镜的制备。采用高分辨率X射线衍射仪（8 keV）测量了X射线超反射镜的反射特性。制备的X射线超反射镜在掠入射角分别为1.052°和1.143°处，反射角度带宽为0.3°，反射率达到20%，可满足KB型显微镜的要求。     

Design, Fabrication and Measurement of Ni/Ti Multilayer Used for Neutron Monochromator

Ni/Ti multilayers, which can be used for neutron monochromators, are designed, fabricated and measured. Firstly, their reflectivities are simulated based on the Nevot-Croce model. Reflectivities of two Ni/Ti multilayer mirrors with periods d = 10.3 nm （M1） and d = 7.8 nm （M2） are calculated. In the calculation, the reflectivity of the Ni/Ti multilayer is taken as a function of the gazing angle with different roughness factors δ =1.0 nm and = 1.5 nm. Secondly, these two multilayers are fabricated by the direct current magnetron sputtering technology. Thirdly their structures are characterized by small-angle x-ray diffraction. The roughness factors are fitted to be 0.68 nm and 1.16nm for M1 and M2, respectively. Finally their reflective performances are measured on the V14 neutron beam line at the Berlin Neutron Scattering Centre （BENSC）, Germany. The experimental data show that the grazing angle of the reflected neutron intensity peak increases, but the reflected neutron intensity decreases, with the decreasing periods of the multilayers.     

全原子分子动力学模拟结合核磁共振波谱研究N-甘氨酰甘氨酸水溶液的结构和弱相互作用

采用分子动力学模拟方法结合核磁共振化学位移系统研究了甘氨酰甘氨酸水溶液体系饱和溶解度范围的弱相互作用. 径向分布函数表明体系中不同类型的原子显示出形成氢键的不同能力. 氢键网络分析发现了不同氢键所能形成的分子簇结构. 随温度变化核磁共振化学位移值用于研究形成氢键的变化情况,并和模拟得到的结果进行比较,模拟和实验结果得到了较好的吻合.     

X射线天文望远镜的进展

综述了近年来X射线天文望远镜(如准直型望远镜、编码孔径望远镜、正入射周期多层膜望远镜、掠入射单层膜望远镜和掠入射非周期多层膜望远镜以及新型的“龙虾眼”型望远镜)的发展；阐述了各种X射线天文望远镜工作的原理和成像特点，指出各种X射线天文望远镜之间的性能是相互补充的；简要说明了国内近年来在X射线天文望远镜研究方面取得的进展，并展望了下一步工作．     

B_4C/Mo/Si high reflectivity multilayer mirror at 30.4 nm

The B4C/Mo/Si high reflectivity multilayer mirror was designed for He-Ⅱradiation (30.4 nm) using the layer-by-layer method. The theoretical peak reflectivity was up to 38.2% at the incident angle of 5℃. The B4C/Mo/Si multilayer was fabricated by direct current magnetron sputtering and measured at the National Synchrotron Radiation Laboratory (NSRL) of China. The experimental reflectivity of the B4C/Mo/Si multilayer at 30.4 nm was about 32.5%. The promising performances of the B4C/Mo/Si multilayer mirror could be used for the construction of solar physics instrumentation.     

低温退火的X射线W/Si多层膜应力和结构性能

W/Si多层膜反射镜在硬X射线天文望远镜中有重要应用. 为减小其应力对反射镜面形和望远镜分辨率的影响, 同时保证较高的反射率, 采用150, 175和200 ℃ 的低温退火工艺对采用磁控溅射镀制的W/Si周期多层膜进行后处理. 利用掠入射X射线反射测试和样品表面面形测试对退火前后W/Si多层膜的应力和结构进行表征. 结果表明, 在150 ℃ 退火3 h 后, 多层膜1级峰反射率和膜层结构几乎没有发生变化, 应力减少约27%; 在175 ℃ 退火3 h后, 多层膜膜层结构开始发生变化, 应力减少约50%; 在200 ℃退火3 h 后, 多层膜应力减小超过60%, 但1级布拉格峰反射率相对下降17%, 且膜层结构发生了较大变化. W, Si界面层的增大和相互扩散加剧是应力和反射率下降的主要原因.