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排序方式: 共有152条查询结果,搜索用时 205 毫秒
91.
本文在低温条件(∽7 K})下对吸附在Ag(100)表面上的单个空心卟啉分子进行了针尖增强拉曼光谱(TERS)研究. TERS光谱的位置依赖特性表明,单个分子内部不同化学组分的局域振动信息是可以区分的;而且进一步的TERS空间成像也表明不同的拉曼谱峰可以具有不同的空间分布特征,它们与相应的振动模式密切相关,甚至能够在亚纳米层次上识别与卟啉芯N-H键有关的振动模式. 这项研究将为深入理解单分子吸附构型的对称性以及单个分子内部的局域振动信息提供有效的手段. 相似文献
92.
Atif Ghafoor Ben Yang Yun-jie Yu Yu-fan Zhang Xian-biao Zhang Gong Chen Yao Zhang Yang Zhang Zhen-chao Dong 《化学物理学报(中文版)》2019,32(3):287-291
Single-molecule tip-enhanced Raman spectroscopy (TERS) has emerged as an important technique for structural analysis at sub-molecular scale. Here in this work, we report aTERS study of an isolated free-base porphyrin molecule adsorbed on the Ag(100) surface at cryogenic temperature (∽7 K). Site-dependent TERS spectra reveal distinct local vibrational information for the chemical constituents within a single molecule. Moreover, distinct spatial features among di erent Raman peaks can be resolved from the TERS mapping images. These images are found to associate with related vibrational modes, enabling to resolve the mode associated with N-H bonds at the sub-nanometer level. This study will provide deep insights into the symmetry of adsorption con gurations and local vibrational information within a single molecule. 相似文献
93.
Optical Review - A reconfigurable and application-specific tunable microwave photonic filter having finite impulse response is proposed. The filter exploits the differential mode group delays of... 相似文献
94.
95.
Theoretical investigations of half-metallic ferromagnetism in new Half-Heusler YCrSb and YMnSb alloys using first-principle calculations 下载免费PDF全文
M Atif Sattar Muhammad Rashid M Raza Hashmi S A Ahmad Muhammad Imran Fayyaz Hussain 《中国物理 B》2016,25(10):107402-107402
Structural,electronic,and magnetic properties of new predicted half-Heusler YCrSb and YMnSb compounds within the ordered MgAgAs Clb-type structure are investigated by employing first-principal calculations based on density functional theory.Through the calculated total energies of three possible atomic placements,we find the most stable structures regarding YCrSb and YMnSb materials,where Y,Cr(Mn),and Sb atoms occupy the(0.5,0.5,0.5),(0.25,0.25,0.25),and(0,0,0) positions,respectively.Furthermore,structural properties are explored for the non-magnetic and ferromagnetic and anti-ferromagnetic states and it is found that both materials prefer ferromagnetic states.The electronic band structure shows that YCrSb has a direct band gap of 0.78 eV while YMnSb has an indirect band gap of 0.40 eV in the majority spin channel.Our findings show that YCrSb and YMnSb materials exhibit half-metallic characteristics at their optimized lattice constants of 6.67 and 6.56 ,respectively.The half-metallicities associated with YCrSb and YMnSb are found to be robust under large in-plane strains which make them potential contenders for spintronic applications. 相似文献
96.
Islam Atif Yasin Tariq Akhtar Muhammad Javed Imran Zahid Sabir Aneela Sultan Misbah Khan Shahzad M. Jamil Tahir 《Journal of Solid State Electrochemistry》2016,20(2):571-578
Journal of Solid State Electrochemistry - Polymer films were cast from aqueous solutions of chitosan (CS) and poly(vinyl alcohol) (PVA) in employing tetraethoxysilane (TEOS) as a crosslinking... 相似文献
97.
98.
Muhammad Tariq Saeed Chani Abdullah M. Asiri Kh. S. Karimov Atif Khan Niaz Sher Bhadar Khan Khalid. A. Alamry 《中国物理 B》2013,(11):629-633
This study presents the fabrication and temperature sensing properties of sensors based on aluminium phthalocyanine chloride(AlPcCl)thin films.To fabricate the sensors,50-nm-thick electrodes with 50-μm gaps between them are deposited on glass substrates.AlPcCl thin films with thickness of 50–100 nm are deposited in the gap between electrodes by thermal evaporation.The resistance of the sensors decreases with increasing thickness and the annealing at 100℃ results in an increase in the initial resistance of sensors up to 24%.The sensing mechanism is based on the change in resistance with temperature.For temperature varying from 25℃ to 80℃,the change in resistance is up to 60%.Simulation is carried out and results obtained coincide with experimental data with an error of±1%. 相似文献
99.
Atif F. Khan Ravishanker Yadav P. K. Mukhopadhya Sukhvir Singh Charu Dwivedi Viresh Dutta Santa Chawla 《Journal of nanoparticle research》2011,13(12):6837-6846
A distinct enhancement of upconversion luminescence from core to core/shell (C/S) structure under low flux near infrared (NIR)
excitation at 976 nm has been achieved in lanthanide (Er3+, Yb3+)-doped NaYF4 core with undoped NaYF4 shell nanoparticles (NP). A green chemistry approach has been taken to synthesize monodisperse monophasic C/S NP with the
core (~20 nm) and shell (~5 nm) crystallizing into cubic phase. Hydrophobic C/S NP have been further made hydrophilic by coating
a transparent SHMP layer without affecting luminescence. C/S (NaYF4: Er, Yb/NaYF4) NP integrated dye-sensitized solar cell indicated 11.9% enhancement in overall conversion efficiency under AM 1.5 conditions,
due to NIR–visible spectrum modification by fluorescent NPs. The results indicate great potential of such upconverting C/S
nanophosphor in solar cell applications. 相似文献
100.
Laser Physics - Zinc oxide nanorods (ZnO-NRs) with high surface to volume ratio and bio compatibility are used as an efficient photosensitizer carrier system for achievement of Hepatocellular... 相似文献