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Confining analyte droplets on visible Si pillars for improving reproducibility and sensitivity of SALDI-TOF MS
摘要： We present a universal method to efficiently improve reproducibility and sensitivity of surface-assisted laser desorption/ionization time of flight mass spectrometry (SALDI-TOF MS). In this method, the Si pillar array with unique surface wettability is used as substrate for ionizing analyte. The Si pillar is fabricated based on the combination of photolithography and metal-assisted chemical etching, which is of hydrophilic top and hydrophobic bottom and side wall. Based on the surface wettability of the Si pillar, a droplet of an aqueous analyte solution can be confined on the top of the Si pillar. After evaporation of solvent, an analyte deposition spot is formed on the top of Si pillar. The visible size of the Si pillar allows the sample spot to be easily found. Meanwhile, the diameter of the Si pillar is smaller than that of the laser, allowing the observation of all analyte molecules under one laser shot. Therefore, the reproducibility and sensitivity are highly improved with this method, which allows for the quantitative analysis. Furthermore, this method is applicable for different analytes dissolved in water, including amino acids, dye molecules, polypeptides, and polymers. The application of this substrate is demonstrated by analyzing real samples at low concentration. It should be a promising method for sensitive and reproducible detection for SALDI-TOF MS.
关键词： Improving reproducibility and sensitivity,SALDI-TOF MS,Visible Si pillars,Minimizing sample spots,Universality
更新于2025-09-23 15:23:52
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gauge models: Towards quantum simulations of the Schwinger-Weyl QED
摘要： We study the ground-state properties of a class of Zn lattice gauge theories in 1 + 1 dimensions, in which the gauge fields are coupled to spinless fermionic matter. These models, stemming from discrete representations of the Weyl commutator for the U(1) group, preserve the unitary character of the minimal coupling and have, therefore, the property of formally approximating lattice quantum electrodynamics in one spatial dimension in the large-n limit. The numerical study of such approximated theories is important to determine their effectiveness in reproducing the main features and phenomenology of the target theory, in view of implementations of cold-atom quantum simulators of QED. In this paper, we study the cases n = 2 ÷ 8 by means of a DMRG code that exactly implements Gauss’s law. We perform a careful scaling analysis and show that, in absence of a background field, all Zn models exhibit a phase transition which falls in the Ising universality class, with spontaneous symmetry breaking of the CP symmetry. We then perform the large-n limit and find that the asymptotic values of the critical parameters approach the ones obtained for the known phase transition of the zero-charge sector of the massive Schwinger model, which occurs at negative mass.
关键词： phase transition,Ising universality class,CP symmetry,Zn lattice gauge theories,cold-atom quantum simulators,DMRG code,quantum electrodynamics
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Simulation of Thermal Photocarrier Escape in Quantum Well Solar Cells: Electron-Electron vs. Electron-Phonon Interaction
摘要： Biometric systems are used for the verification and identification of individuals using their physiological or behavioral features. These features can be categorized into unimodal and multimodal systems, in which the former have several deficiencies that reduce the accuracy of the system, such as noisy data, inter-class similarity, intra-class variation, spoofing, and non-universality. However, multimodal biometric sensing and processing systems, which make use of the detection and processing of two or more behavioral or physiological traits, have proved to improve the success rate of identification and verification significantly. This paper provides a detailed survey of the various unimodal and multimodal biometric sensing types providing their strengths and weaknesses. It discusses the stages involved in the biometric system recognition process and further discusses multimodal systems in terms of their architecture, mode of operation, and algorithms used to develop the systems. It also touches on levels and methods of fusion involved in biometric systems and gives researchers in this area a better understanding of multimodal biometric sensing and processing systems and research trends in this area. It furthermore gives room for research on how to find solutions to issues on various unimodal biometric systems.
关键词： non-universality,Biometrics,identification,unimodal,verification,sensing,multimodal
更新于2025-09-19 17:13:59
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Insight into photocatalytic activity, universality and mechanism of copper/chlorine surface dual-doped graphitic carbon nitride for degrading various organic pollutants in water
摘要： It is still a challenging work to realize the universality of photocatalytic materials for unselective removing various organic pollutants in water. Here a surface dual-doped Cu/Cl-g-C3N4 photocatalyst is firstly prepared, which exhibits much more superior photocatalytic performance for degrading multifarious persistent organic pollutants including tetracycline hydrochloride (TC-HCl), o-chlorophenol, bisphenol A and 2-mercaptobenzothiazole in water than pure g-C3N4. The high-efficiency and unselective photocatalytic degradation performance derives from the surface dual-doped effect of Cu/Cl elements on g-C3N4, which results in the extended visible light harvest range, elevated CB potential and improved the separation efficiency of charge carriers. The intermediate products, degradation pathway, degree of mineralization and reaction mechanism of representative TC-HCl pollutant over the surface dual-doped Cu/Cl-g-C3N4 photocatalyst are revealed in depth. This work makes an important development for treating the persistent organic pollutants in the water environments by exploiting new, low-cost and high-efficiency photocatalytic materials.
关键词： reaction mechanism,photocatalytic degradation,dual-doped Cu/Cl-g-C3N4,various organic pollutants,universality
更新于2025-09-10 09:29:36