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951.
952.
Xianglong Wu Min Tian Wutu Fan Yalei Pan Yuankun Zhai Yinbo Niu Chenrui Li Tingli Lu Qibing Mei 《Journal of fluorescence》2014,24(3):775-786
Eight novel chlorinated fluorescent proteins-labeling probes with a linker and reactive group were prepared in 7 steps by the reaction of chlorinated resorcinols with 3, 6-dichloro-4-carboxyphthalic anhydride in the presence of methanesulfonic acid. Structures of target compounds and intermediates were determined via IR, MS, 1H NMR and element analysis. The spectral properties of the chlorinated fluoresceins were studied. These fluorescent probes showed absorbance peaks at 508–536 nm and fluorescence peaks at 524–550 nm. It was found that they have absorption and emission maxima at long wavelengths and high fluorescence quantum yields. Emission spectra of chlorinated fluoresceins shifted towards long wavelength with increase in chlorine. The probes were used for fluorescence imaging of cells in order to investigate whether they can conjugate to cells. The fluorescence imaging of living cells showed that they were localized in cell nucleus. However, they were localized in cytosol of chemically fixed cells. These probes will be useful reagents for the preparation of stable fluorescent conjugates. 相似文献
953.
Role of helium in the sliding and mechanical properties of a vanadium grain boundary:A first-principles study 下载免费PDF全文
The effects of helium (He) on the sliding and mechanical properties of a vanadium (V) E5(310)/[001] grain boundary (GB) have been investigated using a first-principles method. It has been found that He was energetically favorable sitting at the GB region with a segregation energy of -0.27 eV, which was attributed to the special atomic configurations and charge density distributions of the GB. The maximal sliding energy barrier of the He-doped GB was calculated to be 1.73 J/m^2, 35% larger than that of the clean GB. This suggested that the presence of He would hinder the V GB mobility. Based on the thermodynamic criterion, the total energy calculations indicated that the embrittlement of V GB would be enhanced by He segregation. 相似文献
954.
955.
本文设计了一种基于超材料的偏振不敏感太赫兹宽带吸波体.吸波体包含两层金属和一层中间介质,表面金属层每一个周期单元由五种尺寸接近的金属块按照相邻不同的规律排列成5×5的方形阵列.各种尺寸金属块分别产生单峰谐振吸收,五个谐振吸收峰相互靠近从而产生宽带吸收.通过研究吸波体表面电流和电场z分量分布情况可知,入射太赫兹能量的吸收主要是由y方向上电场引起的电偶极子振荡和z方向上磁场引起的磁极化产生,而且金属层的欧姆损耗起主要作用.仿真结果表明,吸波体吸收率在80%以上的带宽约为1.2 THz,最高吸收率可达98.7%,半峰全宽(FWHM)为1.6 THz,该宽带吸波体的厚度约为中心波长的二十分之一,对偏振方向不敏感,且能实现大角度吸收,在太赫兹频段的电磁隐身、测辐射热探测器以及宽带通信等领域有潜在的应用价值. 相似文献
956.
在精密测量领域,HeNe激光器是制造激光干涉仪的首选.但能够产生中频差4—40 MHz的双折射-塞曼双频HeNe激光器的频差是随机的,小到几百kHz,大到十几MHz.为了让频差能够满足制作双频激光干涉仪的要求,曾出现过弹性加力法、钻孔应力调节法等调整和频差赋值的方法.但这些方法在实际应用中都不是很理想.采用激光内雕法赋值频差,通过在激光器的平面输出镜内部雕刻出不同图案,使平面镜内部产生满足要求的相位延迟,达到为频差赋值的目的.激光内雕法有很多优点:不损害激光器,美观;功率损失小,出光强度可接近原始光强度;可反复赋值,频差在0—60 MHz范围内可调整;频差的稳定性好,采用稳频措施后频差的波动范围小于每小时10 kHz. 相似文献
957.
以poly(3-hexylthiophene)(P3HT)为电子给体,indene-C60bisadduct(ICBA)为电子受体,通过掺杂不同浓度胆甾液晶氯化胆甾醇制备了有机体异质结太阳能电池.结果表明,适当浓度掺杂使器件的开路电压提高到了0.78 V,但短路电流密度却有所降低,填充因子几乎不变,能量转换效率提高了10%.利用X射线、光致发光、原子力显微镜及紫外-可见吸收光谱进行表征,发现液晶掺杂对活性层的结晶度、分子内部排列情况、薄膜表面形貌和光吸收特性等都有明显影响. 相似文献
958.
根据Zernike模式在单位圆的同心孔径圆域内某些模式间具有一定耦合性的结论及对应Zernike模式像差在一定同心光瞳区域内的相互抵消特性,对具有相同角频率不同阶数的Zernike模式建立组合模型,同时根据同心光瞳区域内像差均方根值的降幅比参数给出了同心光瞳直径为4mm时的Zernike模式线性共轭组合模型。最后通过共轭组合模型对光学质量影响的研究发现,共轭模型组合之后能显著提高光学质量。同时也表明Zernike模式组合对光学质量的影响不具备叠加性,而对共轭组合模型表现为补偿关系。 相似文献
959.
High quality above 3-μm mid-infrared InGaAsSb/AIGaInAsSb multiple-quantum well grown by molecular beam epitaxy 下载免费PDF全文
The GaSb-based laser shows its superiority in the 3-4 ~tm wavelength range. However, for a quantum well (QW) laser structure of InGaAsSb/AIGaInAsSb multiple-quantum well (MQW) grown on GaSb, uniform content and high com- pressive strain in InGaAsSb/A1GaInAsSb are not easy to control. In this paper, the influences of the growth tempera- ture and compressive strain on the photoluminescence (PL) property of a 3.0μm lnGaAsSb/A1GaInAsSb MQW sample are analyzed to optimize the growth parameters. Comparisons among the PL spectra of the samples indicate that the Ino.485GaAso.184Sb/Alo.3Gao.45Ino.25Aso.22Sbo.78 MQW with 1.72% compressive strain grown at 460 ~C posseses the op- timum optical property. Moreover, the wavelength range of the MQW structure is extended to 3.83 μm by optimizing the parameters. 相似文献
960.
Time-dependent approach to the double-channel dissociation of the NaCs molecule induced by pulsed lasers 下载免费PDF全文
The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet (TDWP) method with the "split operator-Fourier transform" scheme. At a given wavelength and intensity of laser pulse, the population of each state changing with time is obtained. The photo-absorption spectra and kinetic- energy distribution of the dissociation fragments, which exhibit vibration-level structure and dispersion of the wave packet, respectively, are also obtained. The results show that by increasing the laser intensity, one can find not only the band center shift of the photo-absorption spectrum, but also the change of the fragment energy. The appearance of the diffusive band in the photo-absorption spectrum and the multiple peaks in the kinetic-energy spectrum can be attributed to the effects of the predissoeiation limit and the external field. 相似文献