Raman光谱方法研究三氯甲烷与苯分子间的C/H…π相互作用

测量了不同浓度三氯甲烷（CHCl₃）与苯（C₆H₆）二元溶液的Raman光谱,随C₆H₆浓度的增加,受分子间C/H…π相互作用的影响,CHCl₃中C—H键伸缩振动频率向低波数移动;当CHCl₃体积分数小于40%,C—H键伸缩振动频率不变,分子间C/H…π相互作用达到饱和.分别以CHCl₃和C₆H₆体积分数为70%的CHCl₃-C₆H₆混合溶液为研究对象,测量了它们的高压和低温Raman光谱.根据CHCl₃中C—H键伸缩振动频率随压强和温度的变化关系,得出了分子间C/H…π相互作用对压强和温度的扰动表现出不稳定性.     

高速弹体对钢筋混凝土靶的侵彻/贯穿效应实验研究

为了研究高速弹体对钢筋混凝土靶的侵彻/贯穿效应,以100 mm口径滑膛炮作为发射平台,驱动10 kg级卵形弹体以820～1195 m/s速度撞击强度为31.0～43.6 MPa的钢筋混凝土靶,获得了弹体侵彻/贯穿钢筋混凝土靶的终点弹道实验数据,并对弹体的侵彻/贯穿深度、靶板侧面自由面效应、弹体的变形进行了详细分析。结果表明:弹体的侵彻/贯穿深度为2.2～2.8 m,部分经验公式预估的侵彻/贯穿深度与实验结果吻合较好;当靶面相对尺寸较小且弹速较高时,靶板侧面自由面效应比较明显;当弹速达到1195 m/s时,弹体开始由刚体向半流体转变。     

Stimulated supercontinuum-radiation generation of carbon disulfide by all-trans-β-carotene fluorescence enhancement effect in liquid core optical fibre

We demonstrate stimulated supercontinuum-radiation of carbon disulfide (CS₂) influenced by biological molecules all-trans-β -carotene in liquid core optical fibre (LCOF). By virtue of the broad fluorescence characteristics and large third-order optical nonlinearities of all-{trans}-β-carotene,the high-order Stokes lines of stimulated Raman scattering (SRS) and the multi-order Stokes lines of stimulated Brillouin scattering (SBS) excitated by SRS are observed at low input-laser energies. The results indicate that the fluorescence not only enhances the SRS, but also the SBS. These Stokes lines generate the SRS--SBS supercontinuum radiation (RBSR). A flat-amplitude bandwidth of 110 nm from 515nm to 625nm is observed when a frequency-doubled Nd:YAG laser at 532nm with an energy of 0.86mJ is used. This result is expected to be useful for the multi-wavelength fibre laser.     

Influence of pressure effect on Fermi resonance in binary solution

The Fermi resonance behaviours of the two groups of binary solutions --- pyridine and methanol, benzene and carbon tetrachloride, under different pressures are investigated according to their Raman spectra. The effect of pressure on Fermi resonance in binary solution differs significantly from that in pure liquid. In a binary solution, with the intermolecular distance shortening, the intermolecular interaction potential increases, the shift rates of the Raman spectral lines increase, the spectral line splitting occurs ahead of that in pure liquid, and the wavenumber separation Δ₀ between the unperturbed harmonic levels shifts more quickly, too. The Fermi resonance parameters, the coupling coefficient W and the intensity ratio R of the two Raman bands, decrease rapidly with pressure increasing, and the pressure at which Fermi resonance phenomenon disappears is much lower than that in pure liquid, especially in the solution whose molecules are of the same polarity. This article is valuable in the identification and the assignment of spectral lines under high pressure, as well as the study of high pressure effect, intermolecular interaction, and solvent effects in different cases, etc.     

实现3-2译码及2-3编码的射极根合逻辑电路

本文运用作者最近提出的适用于射极藕合逻辑电路(ECL)设计的代数系统进行了3-2译码器及2-3编码器的ECL电路设计.它们不仅结构简单,而且适用于做成全译码电路及通用编码电路.     

基于一步水热合成荧光碳点的水样中亚硝酸根离子的检测研究

碳基荧光纳米点是一类新型的碳纳米材料,由于具有低毒性、生物兼容性优异、成本低、原料丰富等特点,而被广泛的应用于生物标记、荧光分析、防伪等多方面并具有巨大的应用前景。亚硝酸盐可导致人类高铁血红蛋白血症,有潜在的致癌性。通过盐酸多巴胺、邻苯二胺为原料一步水热法制备,提纯分离后得到目标产物——荧光发射波长为535 nm的黄绿色碳点。实验结果表明,该碳点溶液对亚硝酸根离子具有特异性响应,碳点的荧光被turn-off,检测范围为0～12μg·mL^-1,检出限为0.116 6μg·mL^-1(S/N=3,n=3)。此外,通过三种水样加标实验,回收率在93.9%～97.2%之间(RSD范围为0.03%～0.29%,n=3)。该荧光碳点合成方法快速简便,在污染物检测尤其是有毒亚硝酸盐污染物检测中有着较大的应用潜力,可作为水源地监测的重要补充手段。     

温度变化对单模石英光纤受激拉曼散射附加峰的影响

用10 m长单模石英光纤进行受激拉曼散射温度特性研究, 实验中发现在泵浦光和一级Stokes左右出现了附加峰(称为双峰), 其峰强度随温度的升高(80～295 K)呈现先增加后减弱现象。当温度达到295 K时, 一级Stokes双峰消失。由受激四光子混频理论计算可知,这种双峰现象是受激四光子混频的结果。同时对SRS一级Stokes所产生的受激四光子混频的Stokes频移随温度升高由706.9 cm-1增大到712.9 cm-1和其半宽度由1.75 nm增至2.18 nm的现象也进行了解释。     

干废弃啤酒酵母菌对铅离子的吸附及FTIR分析

以啤酒厂废弃啤酒酵母菌为原料,利用原子吸收光谱(AAS)、扫描电子显微镜/X射线能谱仪(SEM/EDS)、傅里叶红外光谱(FTIR)等手段,研究其对Pb2+的生物吸附规律,并对吸附机理进行了探讨。结果发现实验条件下,啤酒酵母菌对Pb2+的吸附是一个快速过程,实验进行30 min时酵母菌的吸附量为47.6 mg·g-1,吸附效率已达到91.6％,90 min时基本达到吸附平衡,此时酵母菌实验吸附量为48.8 mg·g-1,吸附效率接近94.0％以上。SEM分析发现吸附Pb2+后部分酵母菌出现细胞壁破裂和脱离现象,且认为胞内的溶出物质为酵母菌对Pb2+后期吸附有一定贡献。EDS分析进一步证明Pb2+被吸附到酵母菌细胞上。FTIR分析发现,不同pH和吸附时间红外光谱图均有所差异,特别是羟基、羧基及酰胺的氨基等基团变化显著,认为细胞上的多糖、蛋白质酰胺更多地参与了对Pb2+的化学吸附过程。利用啤酒厂废弃啤酒酵母菌菌体为原料处理工业污水中的Pb2+是一种价格低廉,吸附效果理想的有效途径。     

High-pressure-activated carbon tetrachloride decomposition

The pressure-induced molecular dissociation as one of the fundamental problems in physical sciences has aroused many theoretical and experimental studies. Here, using a newly developed particle swarm optimization algorithm, we investigate the high-pressure-induced molecular dissociation. The results show that the carbon tetrachloride （CC14） is unstable and dissociates into C2C16 and C12 under approximately 120 GPa and more. The dissociation is confirmed by the lattice dynamic calculations and electronic structure of the Pa3 structure with pressure evolution. The dissociation pressure is far larger than that in the case of high temperature, indicating that the temperature effectively reduces the activation barrier of the dissociation reaction of CC14. This research improves the understanding of the dissociation reactions of CC14 and other halogen compounds under high pressures.     

压强对β胡萝卜素分子的电子-声子耦合常数的影响

电子-声子耦合常数不仅可以反映出分子中π电子离域程度的强弱, 有效共轭长度的大小, 同时也可以表征分子中的原子和电子在外界环境作用下的相互振动耦合程度的强弱。在一些研究中电子-声子耦合常数被定义为无量纲的系数。应用R.Tubino等引用的一种有量纲的电子-声子耦合常数, 建立其与黄昆因子的关系式, 进而可以计算出共轭键中单个振动模的数值。压强对多烯分子吸收光谱、拉曼光谱频移影响的研究已有报道, 但对拉曼散射截面、黄昆因子、电子-声子耦合常数的研究还没有报道。测量了β胡萝卜素分子在二硫化碳溶液中0.04～0.60 GPa的压强范围内的紫外-可见吸收光谱和共振拉曼光谱。实验结果表明, 随着压强的增加, CS₂溶液中的β胡萝卜素分子的紫外-可见吸收光谱的吸收带发生明显的红移现象, 而拉曼光谱的特征谱线却发生蓝移的现象, 拉曼散射截面减小, 电子-声子耦合常数增加。其机理是随着压强的增加, β胡萝卜素分子被压缩又结构有序性下降, 导致电子能隙变窄, 有效共轭长度变短, π电子离域范围减小, 拉曼散射截面减小, 黄昆因子、电子-声子耦合常数增加。