Xiamen University

About: Xiamen University is a education organization based out in Amoy, Fujian, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 50472 authors who have published 54480 publications receiving 1058239 citations. The organization is also known as: Amoy University & Xiàmén Dàxué.

Chemical enhancement effects in SERS spectra: A quantum chemical study of pyridine interacting with copper, silver, gold and platinum metals

Abstract: Using density functional theory, we have studied the interactions between pyridine (Py) and coinage metals (silver, copper, and gold) as well as the transition metal platinum. We present here a detailed analysis of the influence of chemical enhancement effects on the SERS signals. We analyze the differential Raman scattering cross sections of the a1 vibrational modes related to Py. The results show that the relative Raman intensities of SERS spectra depend strongly on the binding interaction between Py and the SERS active centers, the electronic property of metal materials, and the incident wavelengths. When the bonding between Py and a SERS site is very weak, analogous to physical adsorption, the Raman spectra of the adsorbed Py are similar to that of free Py. For Py interacting strongly with copper, gold, and platinum clusters, we find that the Raman intensities of the v1, v6a, v9a, and v8a modes of Py are enhanced, whereas the intensity of the v12 mode decreases. To check the enhancement effect of the ...

Failure mode and effects analysis using D numbers and grey relational projection method

Abstract: Failure mode and effects analysis (FMEA) is a widely used risk assessment tool for defining, identifying and eliminating potential failures or problems in products, process, designs and services. Two critical issues of FMEA are the representation and handling of various types of assessments and the determination of risk priorities of failure modes. Many different approaches have been suggested to enhance the performance of traditional FMEA; however, deficiencies exist in these approaches. In this paper, based on a more effective representation of uncertain information, called D numbers, and an improved grey relational analysis method, grey relational projection (GRP), a new risk priority model is proposed for the risk evaluation in FMEA. In the proposed model, the assessment results of risk factors given by FMEA team members are expressed and modeled by D numbers. The GRP method is used to determine the risk priority order of the failure modes that have been identified. Finally, an illustrative case is provided to demonstrate the effectiveness and practicality of the proposed model.

Electrochemical Tip-Enhanced Raman Spectroscopy

Abstract: Interfacial properties are highly important to the performance of some energy-related systems. The in-depth understanding of the interface requires highly sensitive in situ techniques that can provide fingerprint molecular information at nanometer resolution. We developed an electrochemical tip-enhanced Raman spectroscopy (EC-TERS) by introduction of the light horizontally to the EC-STM cell to minimize the optical distortion and to keep the TERS measurement under a well-controlled condition. We obtained potential-dependent EC-TERS from the adsorbed aromatic molecule on a Au(111) surface and observed a substantial change in the molecule configuration with potential as a result of the protonation and deprotonation of the molecule. Such a change was not observable in EC-SERS (surface-enhanced), indicating EC-TERS can more faithfully reflect the fine interfacial structure than EC-SERS. This work will open a new era for using EC-TERS as an important nanospectroscopy tool for the molecular level and nanoscale analysis of some important electrochemical systems including solar cells, lithium ion batteries, fuel cells, and corrosion.