共查询到19条相似文献,搜索用时 171 毫秒
1.
凝聚相中的振动能量弛豫是化学、物理学和生物学中一个非常重要的动力学过程.近年来, 许多实验和理论方法业已建立并用来探索它的微观机理.本文简要介绍一些常用理论方法及其应用,并对将来的发展方向作一展望. 相似文献
2.
3.
4.
5.
6.
综述了近年来量子点的制备方法、功能化修饰以及它在化学和生物分析中应用的研究进展,并对其前景作了简要展望(引用文献59篇)。 相似文献
7.
8.
电穿孔法在量子点标记细胞中的应用 总被引:4,自引:0,他引:4
量子点是一种新兴的荧光标记物,它具有发射峰窄而对称且重叠小、发射波长可调、无光褪色现象以及生物相容性好等优点。可进行生物活体及细胞的标记和检测,用量子点标记细胞的方法目前已有较多报道,其中以利用细胞内吞作用的居多,但这些方法需要在量子点上连接具有穿膜功能的生物试剂,而这又可能导致量子点的聚集以及荧光强度的下降乃至消失, 相似文献
9.
10.
在水相中以巯基乙酸(mercaptoacetic acid, MA)为稳定剂合成了CdSe、CdTe、CdTe/ZnS量子点及谷胱甘肽(glutathione, GSH)为稳定剂合成了CdTe量子点,然后通过卵磷脂和胆固醇修饰制得相应的量子点脂质体。溶血实验证实GSH修饰量子点的溶血率低于MA修饰的量子点45%;脂质体修饰后,量子点的溶血率<5%,达到生物医用材料要求。不同表面修饰的量子点对小鼠毒性存在明显差异,荧光显微镜观察组织切片证实量子点在小鼠体内主要分布在肺、肾、胸腺等组织中,而脂质体量子点在脑组 相似文献
11.
12.
量子化尺寸纳米颗粒及其在生物体系中的作用 总被引:25,自引:1,他引:24
本文从胶体化学与物理化学的角度介绍了纳米颗粒的尺寸量子化效应。介绍了作者所进行的纳米颗粒在生物体系中的应用工作。纳米颗粒金和二氧化硅能显著地提高葡萄糖氧化酶的生物活性。纳米颗粒金能提高视黄醛仿生膜的光电响应电流和寿命。作者用纳米颗粒的吸附浓集效应、吸附定向效应、和量子尺寸效应来解释这些效应 相似文献
13.
14.
荧光碳点探针是近几年来发展起来的一种新型荧光探针,具有传统有机染料、荧光染色蛋白及一般荧光纳米材料无法比拟的独特优势,如具有良好的水溶性、化学惰性、低毒性、易于功能化、抗光漂白性、可调谐和生物相容性等优异性能,因而引起研究者的广泛关注。目前已发展水热法等近十种较为经济便捷的方法,可进行大规模的荧光碳点制备,在细胞功能研究及细胞表面和内部功能分子的探测、组织的成像、病菌的定位等方面得到了较为广泛的应用。笔者对近年来荧光碳点的合成方法、依赖于碳点尺寸和波长等性质的发光性能,以及荧光碳点在生物成像等方面的应用作一简要综述,并对其在药用植物病理方面的应用提出展望,期望为丰富荧光碳点在生物成像领域的应用提供一定的借鉴和参考。 相似文献
15.
Dr. Mahesh Gudem Dr. Markus Kowalewski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(40):e202200781
Triplet-triplet annihilation (TTA) is a spin-allowed conversion of two triplet states into one singlet excited state, which provides an efficient route to generate a photon of higher frequency than the incident light. Multiple energy transfer steps between absorbing (sensitizer) and emitting (annihilator) molecular species are involved in the TTA based photon upconversion process. TTA compounds have recently been studied for solar energy applications, even though the maximum upconversion efficiency of 50 % is yet to be achieved. With the aid of quantum calculations and based on a few key requirements, several design principles have been established to develop the well-functioning annihilators. However, a complete molecular level understanding of triplet fusion dynamics is still missing. In this work, we have employed multi-reference electronic structure methods along with quantum dynamics to obtain a detailed and fundamental understanding of TTA mechanism in naphthalene. Our results suggest that the TTA process in naphthalene is mediated by conical intersections. In addition, we have explored the triplet fusion dynamics under the influence of strong light-matter coupling and found an increase of the TTA based upconversion efficiency. 相似文献
16.
Patricia M. A. Farias Ricardo L. Longo 《International journal of quantum chemistry》2004,97(5):944-948
The occurrence of quantum interference in the Br2 electronic predissociation has been observed for the first time. It is also shown that the quantum interference effects are strongly dependent upon the representation of the molecular properties, such as the kinetic coupling and the transition dipole moment. The fast Fourier transform method implemented within the wave packet formalism was used to simulate the time evolution of the molecular system under the influence of single monochromatic ultrashort laser pulses. The quantum interference has been inferred from the oscillatory behavior of the autocorrelation functions, which have also been used to calculate the cross-sections, the branching ratios, and the selectivity. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 相似文献
17.
M. Hepel 《Russian Journal of Electrochemistry》2008,44(6):663-675
The electrodeposition of copper with formation of narrow nanobridge contacts was investigated. Stable quantum nanobridges
(QNB) with ballistic conductance have been obtained by pulsed Cu deposition/electroetching on Cr interdigitated microelectrodes
nanolithographed on a quartz wafer. The minimum quantum conductance associated with monatomic-wide constriction in the nanobridge
was observed. Stepped differential conductance G = ng
0 (where g
0 is the minimum quantum conductance and n = 1, 2, 3, ...) was generally observed although fractional multiples of go were also found, likely due to the deviations of the nanowire junction geometry from linear configuration and reflection
losses. In the layer-by-layer Cu deposition/etching technique employed for junction formation, the current amplification associated
with interdigitated electrode pattern was utilized, which allowed us for easy electrochemical control with no need for special
instrumentation. Quantum mechanical calculations of the electronic structure of Cu-QNB have been carried out using small-cluster
approach with configuration 14-m-14, where m denotes the number of Cu atoms in the monatomic-wide bridge, and the base electrodes are simulated by clusters with 14 Cu
atoms each. The calculations performed for m = 1 to 4, indicate that corrugations of electron density along the conductance channel virtually disappear for m = 3, whereas for even number of Cu atoms in the bridge, a distinct, very narrow constriction is formed in the center of the
bridge. These results corroborate earlier findings for alkali metals, for which considerable differences between odd and even
number of atoms in a monatomic-wide conductance channel have been reported.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 6, pp. 716–729.
The text was submitted by the authors in English. 相似文献
18.
Luis Esquivias Rocío Litrán Julián Rodríguez-Ortega Eduardo Blanco Milagrosa Ramírez-del-Solar Nicolás de la Rosa-Fox 《Journal of Sol-Gel Science and Technology》1998,11(3):217-227
The influence of using TMOS or TEOS in the formation of CdS quantum dots in a silica matrix have been studied by X-ray absorption spectroscopy (XAS). The amount of Cd-S bonds have been monitored as a function of the nominal Cd concentration. The relative amount of CdS crystals depends on the precursor. The use of TEOS is not recommended because it gives a poor yield, especially for high Cd concentration. A discussion of the influence of CdS concentration in matrices from TMOS is carried out from structural models created from their pore volume distribution. The mean pore size becomes smaller and the size distribution more uniform when CdS concentration increases but the nanocrystals of low CdS nominal content present a more efficient quantum confinement. 相似文献
19.
Quantum dots (QDs) have received more and more attention as a novel example of nanomaterials. Due to their unique fluorescent characteristics,quantum dots have been successfully applied in biotech-nology and medicine applications. Recently,the toxicity and the potential environmental effects of QDs have become a research hotspot. In this paper,toxicological effects of QDs are reviewed,and the prospects and research directions are given based on the analysis of this research field. 相似文献