Search

Illumination of noble metal nanostructures by electromagnetic radiation induces coherent oscillations of conductive electrons on their surfaces. These coherent oscillations of electrons, also known as localized surface plasmon resonances (LSPR), are the underlying physical cause of the electromagnetic enhancement of Raman scattering from analytes located in a close proximity to the metal surface. This physical phenomenon is broadly known as surface-enhanced Raman scattering (SERS). LSPR can decay via direct interband, phonon-assisted intraband, and geometry-assisted transitions forming hot carriers, highly energetic species that are responsible for a large variety of chemical transformations. This review critically discusses the most recent progress in mechanistic elucidation of hot carrier-driven chemistry and catalytic processes at the nanoscale. The review provides a brief description of tip-enhanced Raman spectroscopy (TERS), modern analytical technique that possesses single-molecule sensitivity and angstrom spatial resolution, showing the advantage of this technique for spatiotemporal characterization of plasmon-driven reactions. The review also discusses experimental and theoretical findings that reported novel plasmon-driven reactivity which can be used to catalyze redox, coupling, elimination and scissoring reactions. Lastly, the review discusses the impact of the most recently reported findings on both plasmonic catalysis and TERS imaging.

To investigate the expression and clinical significance of CD5 and CD43 in diffuse large B cell lymphoma (DLBCL) (unspecified).

The turbidite channel of South China Sea has been highly concerned. Influenced by the complex fault and the rapid phase change of lithofacies, predicting the channel through conventional seismic attributes is not accurate enough. In response to this disadvantage, this study used a method combining grey relational analysis (GRA) and support vector machine (SVM) and established a set of prediction technical procedures suitable for reservoirs with complex geological conditions. In the case study of the Huangliu Formation in Qiongdongnan Basin, South China Sea, this study first dimensionalized the conventional seismic attributes of Gas Layer Group I and then used the GRA method to obtain the main relational factors. A higher relational degree indicates a higher probability of responding to the attributes of the turbidite channel. This study then accumulated the optimized attributes with the highest relational factors to obtain a first-order accumulated sequence, which was used as the input training sample of the SVM model, thus successfully constructing the SVM turbidite channel model. Drilling results prove that the GRA-SVM method has a high drilling coincidence rate. Utilizing the core and logging data and taking full use of the advantages of seismic inversion in predicting the sand boundary of water channels, this study divides the sedimentary microfacies of the Huangliu Formation in the Lingshui 17-2 Gas Field. This comprehensive study has shown that the GRA-SVM method has high accuracy for predicting turbidite channels and can be used as a superior turbidite channel prediction method under complex geological conditions. [ABSTRACT FROM AUTHOR]

This paper proposes a new research method for braided river sedimentation on the beach shore based on the action of tidal currents. This study conducts a statistical analysis of the length and width of a single braided river and channel bar sand body, and establishes the relationship function model of the quantitative scale of a single braided river and the channel bar. According to the core and logging data of the Nanwu area of the target oilfield, a quantitative methodology based on the calculation of a single accretion scale is established from three perspectives: the architecture interface identification of the accretion, the occurrence and scale calculation of the interlayer, and the scale calculation of the single accretion. In the Nanwu area, the inclination angle of the accretion interface in the direction of the long axis is 0.78–1.32°, and the inclination angle of the accretion interface in the direction of the short axis is 2.02–3.78°. The density of a single well group is generally 2–3 per well. The length of the single accretion in the channel bar is 700–1500 m. Based on these findings, this paper completes the construction of the architecture of the channel bar, and establishes the quantitative scale calculation method for architecture elements for different levels of braided river reservoirs. The research results provide support for the prediction of the braided river reservoir architecture and the remaining oil in similar blocks. [ABSTRACT FROM AUTHOR]

Natural gas, as one of the main energy sources of the modern clean energy system, is also an important raw material for the chemical industry, and the stable extraction of natural gas reservoirs is often affected by bottom water. It is difficult to control water in natural gas reservoirs, while fractured gas reservoirs are even more demanding. This is due to the complexity of the seepage laws of gas and water in fractures, resulting in the poor applicability of conventional processes for water control. Continuous research is needed to propose a process with effective control capabilities for bottom-water fractured gas reservoirs. Aiming at the above difficulties, this paper is based on a large-scale three-dimensional physical simulation device to carry out physical model design and simulation results testing and analysis. The water control ability of the combination of density-segmented sieve tubes and continuous packers in fractured gas reservoirs is explored. The physical simulation results show that the fracture distribution characteristics control the upward transportation path of bottom water. According to the segmentation characteristics of the fractures at the horizontal section location, optimizing the number of horizontal well screen tube segments and the density of boreholes reduces the cone-in velocity of bottom water before connecting the fractures to a certain extent. And the combined process has different degrees of water control ability for the three stages of bottom water transportation from the fractured gas reservoir to the production well. As the degree of water in the production well increases, the water control ability of the process gradually decreases. After the implementation of the water control process, the water-free gas production period was extended by about 6.84%, and the total production time was extended by about 6.46%. After the shutdown of the horizontal wells, the reduction in daily water production can still reach 21% compared to the natural extraction. The results of this research can provide process suggestions for water control in offshore fractured reservoirs and further ensure stable production in offshore fractured gas reservoirs. [ABSTRACT FROM AUTHOR]

Starting from the formation conditions and generation mechanism of gas hydrates, the influence of external disturbances (temperature, pressure, mechanical, etc.) on their formation process is elaborated, and their respective advantages and disadvantages are analyzed. After analysis, it is found that temperature and pressure disturbances can significantly shorten the induction time to a certain extent, but their promotion mechanism is still in the exploratory stage. Traditional mechanical disturbance techniques are relatively mature, but most of them have structural and energy consumption issues. The new type of external field strengthening can significantly accelerate the formation of crystal nuclei. This provides a basis for further searching for better methods to promote hydrate formation. [ABSTRACT FROM AUTHOR]