1.517 μm附近水汽分子谱线加宽系数的腔衰荡光谱测量

 以超低膨胀系数微晶玻璃为腔体,以分布反馈式激光器为光源,建立了一套等噪声测量灵敏度为3.2×10^-9 cm^-1的调腔式连续波腔衰荡光谱系统。应用该系统对1.517 μm附近(6 586.5~6 596.5 cm^-1范围内)的7条水汽吸收谱线进行了实验研究,测得了这些谱线在氮气、空气环境下的谱线加宽系数。根据测得的结果,得到了此波段水汽的空气加宽系数与氮气加宽系数之比为0.896 9±0.068 7(3倍标准误差范围内),并就测得水汽的谱线加宽系数与HITRAN2004数据库数据进行了比较。     

CH2Cl2分子中CH的摇摆振动与伸缩和弯曲振动的耦合

Infrared absorption spectra of gaseous CH2Cl2 in the regions of 1200-12000 cm-1 were measured using a Bruker IFS 120HR Fourier transform spectrometer in conjunction with a multipass cell. 47 vibrational levels of overtone and combinational spectral lines of the CH stretching (v1, v6), bending (v2), and rocking(v8) modes were analyzed and assigned. Utilizing the normal mode model and considering the coupling among CH stretching, bending and rocking vibrations, values of the harmonic frequency ωi, the anharmonic constant xij, and the coefficients of Fermi and the Darling-Dennison resonances of v1, v6, v2 and v8 modes were also determined from experimental spectral data with nonlinear least-square fitting. These spectral constants reproduced the experimental levels very well. These results showed that Fermi resonance between CH stretching and rocking vibrations (ki88=-254.63 cm-1) is stronger than that between CH stretching and bending vibrations (k122 = 54.87 cm-1); and that Darling-Dennison resonances between CH stretching and bending vibrations (k1166=-215.28 cm-1) is also much stronger than that between CH bending and rocking vibrations (k2288=-5.72 cm-1).     

水溶性CdTe:Mn量子点的双光子吸收

采用激发波长800 nm、脉宽50 fs、重复频率1 kHz的Ti:sapphire放大飞秒激光器作为激发光源,利用开孔Z扫描技术研究了不同粒径的CdTe:Mn量子点的非线性吸收性质。理论计算结果表明,同一生长时间CdTe:Mn量子点的双光子吸收系数是CdTe量子点的1.1倍,其双光子吸收系数随量子点尺寸的减小而增大,这是由于CdTe:Mn量子点非线性吸收属于反饱和吸收,掺杂了Mn元素,减小了表面缺陷浓度,表明掺杂量子点具有很好的双光子吸收现象。     

Construction and application of a novel library: Fourier transform infrared wavelet coefficients library

This article aims at designing a wavelet alternative to Fourier transform infrared spectra (FTIR). In order to select the most suitable wavelet parameters to perform, several decomposition levels and 53 wavelets were tested by trial and error approach, respectively. The result indicated that discrete meyer wavelet (dmey) associated with its third decomposition level was very efficient for this purpose. On the base of it, a novel library named as Fourier transform infrared wavelet coefficients library (FTIR-WC) has been constructed. Finally, two tools such as library search and structure elucidation were developed to evaluate the capability of the new library system. The results obtained were also compared with those from FTIR library by a variety of indices. The results suggested that the new library performed better but with less volume. This work is expected to propose a novel and practical strategy in infrared spectroscopic analysis.     

硝酸钐水合物热分解过程的研究

Sm(NO_3)_3·6H_2O热分解过程的研究工作虽有文献报道,但结果不尽相同。文献[2]不同于文献[1,3],认为分解过程中存在无水盐阶段;文献[3]不同于文献[1,2],认为分解过程中存在低水合物。而且文献尚缺低水合物热分解机理的报道。我们也曾做过一些工作,但脱水阶段也不详尽。为此,我们详细地研究了Sm(NO_3)_3·nH_2O(n=     

Si1-xGex合金半导体中CiCs和CiOi缺陷随Ge含量的变化

采用从头计算(ab initio)的方法对Si和Si1-xGex合金半导体材料中CiCs 缺陷的性质进行探讨,同时也对比调查了CiOi 缺陷在Si和Si1-xGex合金中的性质. 在不同Ge含量的Si1-xGex合金中CiCs和CiOi缺陷的结构都具有较好的稳定性;从能量学角度,Ge原子不能与C或O原子直接成键. CiCs缺陷的A型和B型结构在Si1-xGex合金中表现出的行为基本类似,但是A型结构随着Ge含量的增加形成能逐渐减小,结构越来越稳定,而B型结构的形成能先有所下降后逐渐增加;A型和B型结构的能量差值随着Ge含量的增加先在小范围内变化后迅速下降. CiOi缺陷形成能的变化特征较为复杂. 纯Si体系在1000K及以上温度的等温退火过程中,CiCs缺陷的A型结构会向B型结构转变;Si1-xGex合金在进行等温退火时CiCs缺陷的A型结构的变化特征与退火温度、Ge含量和Ge取代的位置等因素有关.     

Relative and Absolute Configuration of Vatiparol (1 mg): A Novel Anti‐inflammatory Polyphenol

Bioactive natural products offer multiple opportunities for the discovery of novel chemical entities with potential pharmaceutical, nutraceutical and agrochemical applications. Many new organic compounds with novel scaffolds are isolated in small quantities and established methods often fail to determine the structure and bioactivity of such novel natural products. To meet this challenge, we present here a new methodology combining RDC (residual dipolar coupling)‐based NMR spectroscopy in microtubes, with a motif‐inspired biological assessment strategy. Using only one milligram (ca. 1.5 μmol) of sample, the new protocol established the bioactivity as well as the relative and absolute configuration of vatiparol obtained from Vatica parvifolia. Vatiparol is unique in its unprecedented carbon skeleton and selective inhibitory effect on the expression of monocyte chemo‐attractant protein‐1 (MCP‐1, also known as CCL2). The plausible biosynthetic pathway of vatiparol is briefly discussed. The approach introduced here promises to be widely applicable to the determination of the structure and bioactivity of structurally unknown organic samples available in very limited amounts.     

化学发光法测定甲萘威

在NaOH介质中,铁氰化钾氧化鲁米诺产生化学发光,甲萘威对该发光反应有较强的抑制作用且抑制发光强度与甲萘威的浓度呈较好的线性关系,基于此性质建立了测定甲萘威的新方法。在实验的优化条件下,测定甲萘威的检出限为5.5×10-11mol.L-1,线性范围为1.5×10-10—4.0×10-8mol.L-1,对5.0×10-9mol.L-1甲萘威进行了11次平行测定,其RSD为1.74%。该法用于合成样品中甲萘威的测定,结果令人满意。     

The Cellular Interactions of PEGylated Gold Nanoparticles: Effect of PEGylation on Cellular Uptake and Cytotoxicity

Poly(ethylene glycol) (PEG) is frequently used to coat various medical nanoparticles (NPs). As PEG is known to minimize NP interactions with biological specimens, the question remains whether PEGylated NPs are intrinsically less toxic or whether this is caused by reduced NP uptake. In the present work, the effect of gold NP PEGylation on uptake by three cell types is compared and evaluated the effect on cell viability, oxidative stress, cell morphology, and functionality using a multiparametric methodology. The data reveal that PEGylation affects cellular NP uptake in a cell‐type‐dependent manner and influences toxicity by different mechanisms. At similar intracellular NP numbers, PEGylated NPs are found to yield higher levels of cell death, mostly by induction of oxidative stress. These findings reveal that PEGylation significantly reduces NP uptake, but that at similar functional (= cell‐associated) NP levels, non‐PEGylated NPs are better tolerated by the cells.     

脉冲激光频域干涉技术在超快动力学物理中的应用

介绍了一种具有fs时间分辨力的超短脉冲激光频域干涉测试技术,详细论述了该技术的工作原理和系统构成,指出传输时间差和相位差是影响频域干涉条纹周期的主要因素。采用脉冲激光频域干涉仪测量了200 nm厚度铝膜在波长800 nm、单脉冲能量0.7 mJ、脉宽35 fs脉冲激光作用下的运动速度剖面。在单次飞秒脉冲激光作用下,铝膜自由面的运动速度峰值可达960 m/s,速度剖面的上升前沿小于5.77 ps,表明脉冲激光频域干涉技术可用于测量材料在超快脉冲激光作用下的冲击动力学参数。