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931.
Visualization of Vibrational Modes in Real Space by Tip‐Enhanced Non‐Resonant Raman Spectroscopy
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Dr. Sai Duan Dr. Guangjun Tian Prof. Dr. Yi Luo 《Angewandte Chemie (International ed. in English)》2016,55(3):1041-1045
We present a general theory to model the spatially resolved non‐resonant Raman images of molecules. It is predicted that the vibrational motions of different Raman modes can be fully visualized in real space by tip‐enhanced non‐resonant Raman scattering. As an example, the non‐resonant Raman images of water clusters were simulated by combining the new theory and first‐principles calculations. Each individual normal mode gives rise its own distinct Raman image, which resembles the expected vibrational motions of the atoms very well. The characteristics of intermolecular vibrations in supermolecules could also be identified. The effects of the spatial distribution of the plasmon as well as nonlinear scattering processes were also addressed. Our study not only suggests a feasible approach to spatially visualize vibrational modes, but also provides new insights in the field of nonlinear plasmonic spectroscopy. 相似文献
932.
Man-Cheng Long Ting Wang Ping-Hui Duan You Gao Xiu-Li Wang Gang Wu Yu-Zhong Wang 《Journal of Energy Chemistry》2022,(2):9-18
Poly(ethylene oxide)(PEO)and its derivatives based gel polymer electrolytes(GPEs)are severely limited in advanced and safe lithium-ion batteries(LIBs)owing to the intrinsically high flammability of liquid electrolytes and PEO.Directly adding flame retardants to the GPEs can suppress their flammability and thus improve the safety of LIBs,but results in deteriorative electrochemical performance.Herein,a novel GPE with chemically bonded flame retardant(i.e.diethyl vinylphosphonate)in cross-linked polyethylene glycol diacrylate matrix,featuring both high-safety and high-performance,is designed.This as-prepared GPE storing the commercial 1 mol L-1 LiPF6 electrolyte resists high temperature of 200℃and cannot be ignited as well as possesses a high ionic conductivity(0.60 m S cm-1)and good compatibility with lithium.Notably,the LiFePO4/Li battery with this GPE delivers a satisfactory capacity of 142.2 m A h g-1 and a superior cycling performance with a capacity retention of 96.3%and a coulombic efficiency of close to 100%for 350 cycles at 0.2 C under ambient temperature.Furthermore,the battery can achieve steady charge–discharge for 100 cycles with a coulombic efficiency of 99.5%at 1 C under 80℃and run normally even at a high temperature of 150℃or under the exposure to butane flame.Differential scanning calorimetry manifests significantly improved battery safety compared to commercial battery systems.This work provides a new pathway for developing next-generation advanced LIBs with enhanced performance and high safety. 相似文献
933.
934.
Zhang Qun Ge Kun Duan Jianlei Chen Shizhu Zhang Ran Zhang Cuimiao Wang Shuxiang Zhang Jinchao 《Journal of nanoparticle research》2014,16(11):1-12
The sintering of a silver (Ag) nanoparticle film by laser beam irradiation was studied using a CW DPSS laser. The laser sintering of the Ag nanoparticle thin film gave a transparent conductive film with a thickness of ca. 10 nm, whereas a thin film sintered by conventional heat treatment using an electronic furnace was an insulator because of the formation of isolated silver grains during the slow heating process. The laser sintering of the Ag nanoparticle thin film gave a unique conductive network structure due to the rapid heating and quenching process caused by laser beam scanning. The influences of the laser sintering conditions such as laser scan speed on the conductivity and the transparency were studied. With the increase of scan speed from 0.50 to 5.00 mm/s, the surface resistivity remarkably decreased from 4.45 × 108 to 6.30 Ω/sq. The addition of copper (Cu) nanoparticles to silver thin film was also studied to improve the homogeneity of the film and the conductivity due to the interaction between the oxidized surface of Cu nanoparticle and a glass substrate. By adding 5 wt% Cu nanoparticles to the Ag thin film, the surface resistivity improved to 2.40 Ω/sq. 相似文献
935.
This paper studies the damage-viscoelastic behavior of composite solid propellants of solid rocket motors(SRM).Based on viscoelastic theories and strain equivalent hypothesis in damage mechanics,a three-dimensional(3-D)nonlinear viscoelastic constitutive model incorporating with damage is developed.The resulting viscoelastic constitutive equations are numerically discretized by integration algorithm,and a stress-updating method is presented by solving nonlinear equations according to the Newton-Raphson method.A material subroutine of stress-updating is made up and embedded into commercial code of Abaqus.The material subroutine is validated through typical examples.Our results indicate that the finite element results are in good agreement with the analytical ones and have high accuracy,and the suggested method and designed subroutine are efficient and can be further applied to damage-coupling structural analysis of practical SRM grain. 相似文献
936.
The structural properties, phase stability, electronic structure, elastic properties, and optical properties of Ca5(PO3)4F (FA), Ca5(PO3)4Cl (ClA) and Ca5(PO3)4Br (BrA) are studied by DFT calculations with the generalized gradient approximation. 相似文献
937.
Weihong Long Ming Duan Shenwen Fang Liehui Zhang Linyu Li Ya Hui Tian 《Journal of Macromolecular Science: Physics》2014,53(4):693-706
Three new surfactant macromonomers (SMM) with different ethylene oxide (EO)/propylene oxide (PO) ratios (for SMM1, SMM2, and SMM3, the EO/PO ratios were 1:0.5, 1:0.9, and 1:1.25, respectively) were synthesized by the reaction between PEO-PPO di-block polymers having terminal tertiary amine groups and chloropropene. Graft copolymers of acrylamide and SMM (PAM-g-SMM) were prepared with different SMMs and grafting densities in water, and the products were confirmed by FTIR and elemental analysis. Owing to the strong hydrophobicity of the graft, the PAM-g-SMM3 was not water soluble. However, PAM-g-SMM1 and PAM-g-SMM2 aqueous solutions had good surface activity and their surface tensions were 44.26 and 37.63 mN/m at a concentration of 1000 mg/L, respectively. In general, in diluted graft PAM solutions, the copolymer predominantly formed intrapolymeric associates. The PAM-g-SMM2 was both thermo-associative and salt-associative in dilute solution. For PAM-g-SMM2, when the temperature and salt concentration increased, interpolymeric aggregations were formed. 相似文献
938.
In recent years, many pose estimation algorithms were developed, and have been successfully applied to solve unmanned aerial vehicle (UAV) aerial refueling pose estimation problems. This paper mainly focuses on solving this problem under serious turbulences circumstance. The extended Kalman filter is a set of mathematical equations to estimate the state of a process, which is able to support estimations of past, present, and even future states. In reference to previous papers and some simulations, we build up the noise models of refueling boom and atmospheric turbulence. Then, an extend Kalman filter is adopted to solve the pose estimation problem in UAV aerial refueling with serious turbulences. The experimental results demonstrate the feasibility and effectiveness of our proposed approach. 相似文献
939.
In this paper, a hybrid Particle Chemical Reaction Optimization (PCRO) algorithm and lateral inhibition is proposed to solve the image matching problem. Lateral inhibition has the ability to enhance the characters of image, which can help to improve the accuracy of image matching. In order to overcome the shortcomings of basic Chemical Reaction Optimization (CRO) algorithm, we improve CRO by proposing PCRO which inspired from the thought of Particle Swarm Optimization (PSO). Comparative experimental results in image matching show that our proposed hybrid method performs much better than other bio-inspired algorithms. 相似文献
940.
This paper describes a novel chaotic biogeography-based optimization (CBBO) algorithm for target detection by means of template matching to meet the request of unmanned aerial vehicle (UAV) surveillance. Template matching has been widely applied in movement tracking and other fields and makes excellent performances in visual navigation. Biogeography-based optimization (BBO) algorithm emerges as a new kind of optimization method on the basis of biogeography concept. The idea of migration and mutation strategy of species in BBO contributes to solving optimization problems. Our work adds chaotic searching strategy into BBO and applies CBBO in template matching. By utilizing chaotic strategy, the population ergodicity and global searching ability are improved, thus avoiding local optimal solutions during evolution. Applying the algorithm to resolving template matching problem overcomes the defects of common image matching. Series of experimental results demonstrate the feasibility and effectiveness of our modified approach over other algorithms in solving template matching problems. Our modified BBO algorithm performs better in terms of convergence property and robustness when compared with basic BBO. 相似文献