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991.
《印度化学会志》2021,98(9):100122
Salophen is a weakly fluorescent Schiff base which forms emissive co-ordination complexes with Zn2+ and Al3+. The complex with Al3+ is significantly more fluorescent than that with Zn2+, presumably because the dimeric complex with Zn2+ is associated with additional nonradiative channels. This contention has been put to test, through a careful investigation of excited state dynamics of the anionic form of salophen (Sal2−), which is the form in which the ligand exists in the complexes. The emissive excited state of the anion (Sal2−) has been found to be solvated and conformationally relaxed, over tens of picosecond. It is significantly more fluorescent than the neutral compound, with fluorescence lifetime that is longer by almost two orders of magnitude. Fluorescence lifetime of the anion is in fact longer than that of the complex with Zn2+ and slightly less than that of the complex with Al3+. So, the earlier hypothesis about additional nonradiative deactivation pathways in the Zn2+ complex gains credence from the present study. 相似文献
992.
航空遥感监测中变焦镜头的广泛应用以及飞行高度的变化会获得不同地面分辨率的航空影像,因此为了实时监控到飞行区域的整体情况,需要对不同地面分辨率的图像进行拼接。提出了针对不同地面分辨率图像进行拼接的方法。首先用四分法对图像进行分割,检测变化倍率,选择配准策略;然后用基于加速鲁棒性特征(Speeded-Up Robust Features,SURF)的算法对相邻图像进行拼接。获得了焦距变化从高倍过渡到低倍,或从低倍过渡到高倍的拼接图像。通过航空变焦模拟影像的拼接实验和地面变焦影像的拼接实验表明,该方法能够对不同地面分辨率的图像进行拼接,且拼接结果均以高分辨率为基准。 相似文献
993.
The Z-scan measurements for the non-centrosymmetric optical crystals β-BaTeMo2O9 (BTMO) were performed. The corresponding experiments were carried out using the 5 ns pulses of the second harmonic of a nanosecond Nd:YAG laser at the 532 nm wavelength. It was shown that the studied crystals possess promising third-order optical susceptibilities, which allow to use the crystal as optical limiters. The comparison with other oxide materials is presented. To clarify the origin of the observed effect, the electronic and optical properties of BTMO were calculated using the density functional theory (DFT)-based method. The performed calculations of the electronic and optical properties revealed certain peculiar features that can be suitable for the nonlinear optical applications. The relation between the observed nonlinear optical features and the calculated band structure is emphasized. The values of the calculated band gap and refractive index for β-BaTeMo2O9 are also reported. 相似文献
994.
H. DagistanliR.H. Mutlu 《Radiation Physics and Chemistry》2012,81(3):240-241
The occupation numbers of the 3d transition metals are calculated as a function of pressure by means of the linear muffin-tin-orbital method. This data is used with the multiconfiguration Dirac-Fock (MCDF) X-ray intensity ratios (R) to estimate the variation of the intensity ratios of 3d metals with pressure. It is found that R decreases with pressure for the early 3d metals whereas it increases for the heavier 3d transition metals. 相似文献
995.
M. Lachica E. Barahona 《International journal of environmental analytical chemistry》2013,93(1-4):219-221
Abstract The effect of using solution matrices in calibration standards different from those employed for the extraction steps in the determination of Cd, Cr, Cu, Ni and Zn were tested. Cu and Zn are little affected by matrix effects but, if the extractant is ammonium acetate, the use of other matrices may result in too high Cd, Cr and Ni values. 相似文献
996.
Two functional polyurethanes (P1 and P2) bearing a large π electron conjugated chromophoric pendant were synthesized and characterized by FT‐IR, 1H‐NMR and UV‐Vis absorption spectra. Their optical limiting properties were evaluated. The results show that P1 and P2 show novel optical limiting properties, which are assigned to a long π electron conjugated chromophoric pendant. It was found that their optical limiting properties were affected simultaneously by solution concentration and P2 displays a better optical limiting property than P1 at the same solution transmittance, although that P1 has larger χ(3) (4.28×10?11 esu) than P2 (0.87×10?11 esu), and their optical limiting mechanism is investigated. 相似文献
997.
Investigation on the stress behavior of cellulose acetate and the development of highly moisture‐resistant optical films for display devices 下载免费PDF全文
Min Sang Park Seokwon Jung So Jeong Heo Seung Geol Lee 《Journal of Polymer Science.Polymer Physics》2017,55(19):1470-1479
An optical film with high optical anisotropy was prepared by the stretching of a cellulose acetate film and the consequential orienting of a retardation‐enhancing additive. The change in retardation in response to moisture absorption was explored and it was found that the degree of the retardation variation is strongly related to the stretching temperature. Stress generated by the stretching and its relaxation was systematically investigated to elucidate the effect of stretching temperature on the irreversible change in retardation upon moisture absorption. The results show that the magnitude of releasable stress plays an important role in controlling changes in optical properties. In addition, the difference in the deformation behavior between glassy and rubbery states should be taken into account in the development of a moisture‐resistant optical film. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1470–1478 相似文献
998.
999.
Raman spectra of the Schiff 's base liquid crystalline compound 5O5, N-(4- n-pentyloxybenzylidene)-4'-n-pentylaniline, have been recorded as a function of temperature from 22 to 80°C in the 1140-1220 cm-1 and 1550-1640 cm-1 spectral regions. From careful deconvolution of the spectral features using Lorentzian profiles, precise values of peak positions, integrated intensities and linewidths of some selected Raman bands were obtained. The variations of the Raman spectral parameters with temperature are discussed in terms of changes in the molecular alignment and its effect on intra-/inter-molecular interactions at the Cr-G, G-SmF, SmF-SmC and SmA-N phase transitions. From a detailed study, it is inferred that the increased orientational/vibrational freedom of the alkyl chains, as well as the delocalization of the electron clouds, is responsible for the spectral anomalies at the Cr-G transition. Loss of positional ordering and twist around the -C6H4-N= bond takes place at the SmF-SmC transition. In the SmA-N transition, some evidence for the formation of cybotactic clusters was obtained. 相似文献
1000.
赵卫 《广东微量元素科学》2017,24(6)
目的了解花都区开展预防梅毒母婴传播阻断项目的实施成效,降低梅毒母婴传播率。方法对首次就诊的孕产妇进行梅毒筛查,对检出的梅毒阳性孕产妇进行规范治疗,并对其所生婴儿进行随访管理。结果 2012—2016年感染产妇孕期确诊率达71.18%,接受规范治疗率达53.02%,新生儿预防性治疗率75.8%,儿童3月龄梅毒检测率为50.86%,6月龄检测率42.55%。结论实施预防梅毒母婴传播项目,可以有效地阻断梅毒的母婴传播,降低梅毒母婴传播率,提高妇女儿童的健康水平。 相似文献