银薄层控制金纳米四足体的重塑和等离激元调谐

探究了溶液中不同温度以及不同溶液成分(I^-的引入)对金纳米四足体(GNTPs)重塑过程的影响，表明了GNTPs的重塑机制为Ostwald熟化，即弱结合的表面Au原子在高凸曲率区域溶解和在凹区域重新沉积。这种重塑过程可以随时通过镀银薄层在几秒内阻止，GNTPs的形貌可以在最大程度上得到很好的稳定，从而也可以防止其光学性质的演变。在此基础上，通过紫外可见近红外(UV-Vis-NIR)吸收光谱和基于同步辐射的小角X射线散射(SAXS)进一步研究了GNTPs/Ag的稳定性，并通过表面增强拉曼散射(SERS)光谱证实了GNTPs/Ag的光学响应。     

聚倍半硅氧烷复合超支化聚酯的结构及相容性

以三羟甲基丙烷(TMP)为内核, 二羟甲基丙酸(DMP)为支化单元用准一步法合成了重均分子量为12100的第四代端羟基脂肪族超支化聚酯G4, 并与聚甲基三乙氧基硅烷(PMSQ)共混制备出一系列不同质量分数的复合物. 利用固体核磁共振(NMR)等方法表征了各个样品的结构和反应程度, 并通过测量¹H T_1ρ值发现超支化聚酯与聚倍半硅氧烷之间具有较好的相容性, 相容尺寸为3~5 nm.     

Ruthenium(II) complexes containing a pendant methanol amidogen induce apoptosis in SGC-7901 cells through a ROS-mediated mitochondrial dysfunction pathway

Transition Metal Chemistry - A phenanthrene derivative with a pendant methanol amidogen TFCPIP and its two ruthenium(II) complexes [Ru(phen)2(TFCPIP)](ClO4)2 (1) and [Ru(dmp)2(TFCPIP)](ClO4)2 (2)...     

HF在α-AlF3(0001)表面吸附的密度泛函理论研究

利用密度泛函理论系统研究了不同覆盖度下HF在3F、2F、1F与Al 终端的α-AlF₃(0001)表面的吸附行为, 分析了HF与不同终端表面相互作用的电子机制. 计算结果表明: HF在3F终端的α-AlF₃(0001)表面物理吸附; 在2F及1F终端表面化学吸附, 形成Al-F键和FHF结构, 使HF分子活化, 可以参加下一步的氟化反应; 在Al 终端表面解离吸附形成Al-F与Al-H键. 3F、2F、1F及Al 终端表面配位不饱和数目分别为0、1、2与3配位.不同覆盖度研究表明, 在2F终端表面上, 吸附一个HF分子使表面Al 配位达到饱和, 后续吸附的HF为物理吸附; 而在1F与Al 终端表面仍可化学吸附. 因此, 推测α-AlF₃暴露不同终端表面中Al 原子配位不饱和数越高, 其对HF吸附与活化能力越强, 可能的氟化催化反应活性越高. 差分电荷密度与电子态密度分析表明, HF与3F终端α-AlF₃(0001)表面发生弱相互作用, 而与2F、1F与Al 终端表面形成较强的电子相互作用.     

Hydrogen fluoride adsorption and reaction on the α-Al2O3(0001) surface: a density functional theory study

The adsorption and reaction behaviors of HF on the α-Al(2)O(3)(0001) surface are systematically investigated using density functional theory method. By increasing the number of HF molecules in a p(2 × 1) α-Al(2)O(3)(0001) slab, we find that HF is chemically dissociated at low coverage; while both physical and dissociative adsorption occurs at a 3/2 monolayer (ML) coverage. At the same coverage (1.0 ML), diverse configurations of the dissociated HF are obtained in the p(2 × 1) model; while only one is observed in the p(1 × 1) slab due to its smaller surface area compared with the former one. Preliminary fluorination reaction study suggests that the total energy of two dissociated HF in the p(2 × 1) slab increases by 1.00 and 0.72 eV for the formation and desorption of water intermediate, respectively. The coadsorption behaviors of HF and H(2)O indicate that the pre-adsorbed water is unfavorable for the fluorination of Al(2)O(3), which is well consistent with the experimental results. The calculated density of states show that the peak of σ(H-F) disappears, while the peaks of σ(H-O) and σ(Al-F) are observed at -8.4 and -5 to -3 eV for the dissociated HF. Charge density difference analysis indicates that the dissociated F atom attracts electrons, while no obvious changes on electrons are observed for the surface Al atoms.     

Quality Evaluation of Angelica sinensis by Simultaneous Determination of Ten Compounds Using LC-PDA

A simple, rapid and valid analysis method for simultaneously determination of ten characteristic components, including six phthalides [(Z)-ligustilide, (Z)-butylidene phthalide, riligustilide, levistolide A, (3Z)-(3aR,6S,3′R,8′S)-3a.8′,6.3′-diligustilide and 3,9-dihydroxyl-ligustilide], three aromatic acids (o-phthalic acid, vanillic acid and ferulic acid) and one macrolide (brefeldin A), in the radix of Angelica sinensis, a valued traditional Chinese medicinal herb was developed by liquid chromatography coupled with photodiode array detection. Riligustilide, levistolide A, (3Z)-(3aR,6S,3′R,8′S)-3a.8′,6.3′-diligustilide, 3,9-dihydroxyl-ligustilide and brefeldin A were first quantitatively determined in Angelica sinensis. Separation was performed on an Alltima C-18 analytical column by gradient elution with (A) 0.2% aqueous formic acid and (B) methanol as mobile phase. The column temperature was set at 25 °C. The method was validated for system suitability, precision accuracy and linearity. The average recovery of the method was 93.8–102.2% and linearity was (R ² > 0.998). Furthermore, the method was successfully applied to the simultaneous determination of ten analytes in 46 samples of A. sinensis from various sources including different collecting locations, harvesting time, storage time, drying methods, and medicinal portions of the herb. The results obtained suggest that the method can efficiently evaluate the quality of A. sinensis from different sources, which benefit its quality control.     

Microwave backscattering from the sea surface with breaking waves

Based on the effective medium approximation theory of composites, the whitecap-covered sea surface is treated as a medium layer of dense seawater droplets and air. Two electromagnetic scattering models of randomly rough surface are applied to the investigation of microwave backscattering of breaking waves driven by strong wind. The shapes of seawater droplets are considered by calculating the effective dielectric constant of the whitecap layer. The responses of seawater droplets shapes, such as sphere and ellipsoid, to the backscattering coefficient are discussed. Numerical results of the models are in good agreement with the experimental measurements of horizontally and vertically polarized backscattering at microwave frequency 13.9GHz and different incidence angles.     

平行排列丝状液晶在超短脉冲激光激励下发生瞬态扭曲形变的最佳偏振角

利用光学相位延迟法，观察到平行排列丝状液晶在超短脉冲激光（10ns）激励下的瞬态扭曲形变.实验结果表明，虽然脉冲激光的电场强度远远大于液晶发生扭曲形变的阈值，但并不能保证液晶会发生瞬态扭曲形变.这主要是因为脉冲激光的激励时间非常短，而液晶分子发生扭曲形变的响应时间相对较长，从而使其来不及形变.分析发现：激励激光的偏振方向与平行排列丝状液晶分子的最佳夹角是45°.利用此条件，观察到掺微量D型苏氨酸卟啉的平行排列丝状液晶在超短脉冲激光激励后具有记忆效应，这在光存储和记忆显示方面有很大的实用价值.     

含羞草中新黄酮碳苷的结构鉴定

研究了海南含羞草(Mimosa pudica)的化学成分,利用Diaion HP-20、Toyopearl HW-40、MCI-Gel CHP-20、Sephadex LH-20、RP18及硅胶等柱色谱法对海南含羞草成分进行分离纯化。根据理化性质和波谱方法(1H-NMR、13C-NMR、1H-1HCOSY、HSQC、HMBC、ESI-MS、IR等)鉴定化合物的结构。结果表明,新化合物为5,7,3′,4′-四羟基-6-C-[β-D-芹糖-(1→4)]-β-D-葡糖黄酮碳苷;另一已知化合物5,7,4′-三羟基-8-C-β-D-葡糖黄酮碳苷为首次从该植物中分离得到。     

Two new flavonoids from Artemisia argyi with their anticoagulation activities

A new flavone glycoside, eupatilin 7-O-β-d-glucopyranoside (1) and a new flavone, 5,6,2′,4′-tetrahydroxy-7,5′-dimethoxyflavone (2), were isolated from Artemisia argyi. Their structures were unambiguously elucidated by extensive spectroscopic analysis. Both flavonoids were evaluated for in vitro anticoagulation activities. Compound 1 significantly extended thrombin time. Compound 2 had obvious effect in increasing prothrombin time.