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Surface Dynamics and Ligand–Core Interactions of Quantum Sized Photoluminescent Gold Nanoclusters
摘要： Quantum-sized metallic clusters protected by biological ligands represent a new class of luminescent materials; yet the understanding of structural information and photoluminescence origin of these ultrasmall clusters remains a challenge. Herein we systematically study the surface ligand dynamics and ligand?metal core interactions of peptide-protected gold nanoclusters (AuNCs) with combined experimental characterizations and theoretical molecular simulations. We show that the peptide sequence plays an important role in determining the surface peptide structuring, interfacial water dynamics and ligand?Au core interaction, which can be tailored by controlling peptide acetylation, constituent amino acid electron donating/withdrawing capacity, aromaticity/hydrophobicity and by adjusting environmental pH. Specifically, emission enhancement is achieved through increasing the electron density of surface ligands in proximity to the Au core, discouraging photoinduced quenching, and by reducing the amount of surface-bound water molecules. These findings provide key design principles for understanding the surface dynamics of peptide-protected nanoparticles and maximizing the photoluminescence of metallic clusters through the exploitation of biologically relevant ligand properties.
关键词： gold nanoclusters,photoluminescence,surface dynamics,ligand-core interactions,peptide protection
更新于2025-09-09 09:28:46
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The future SwissFEL facility – challenges from a radiation protection point of view
摘要： The Swiss Free Electron Laser is a new large-scale facility currently under construction at the Paul Scherrer Institute. Accessible areas surrounding the 720 m long accelerator tunnel, together with the pulsed time structure of the primary beam, lead to new challenges for ensuring that the radiation level in these areas remains in compliance with the legal constraints. For this purpose an online survey system based on the monitoring of the ambient dose rate arising from neutrons inside of the accelerator tunnel and opportunely calibrated to indicate the total dose rate outside of the tunnel, will be installed. The presented study provides a conceptual overview of this system, its underlying assumptions and measurements so far performed to validate its concept.
关键词： online survey system,neutrons,ambient dose rate,accelerator tunnel,SwissFEL,radiation protection
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Smart Systems and Technologies (SST) - Osijek, Croatia (2018.10.10-2018.10.12)] 2018 International Conference on Smart Systems and Technologies (SST) - Arc Flash Incident Energy Simulation in PV Power Plant Connected to Distribution Network
摘要： This paper presents a method for computation of arc flash incident energy in mixed alternating current (AC)/direct current (DC) systems with DC units such as strings, panel cabinets, inverters in Photovoltaic (PV) power plant, as well as on AC side behind the inverters connected to the distribution network. It also gives measures to reduce the risk and consequences of electrical arc flash that may occur due to live work or maintenance on DC and AC part of the PV power plant. By exploiting an advanced smart protection software for coordination of protective devices, this paper shows how we can reduce the risk of these harmful consequences for the personnel working in such power plants. An example case of a PV power plant with rated power of 300 kW is modelled with with its all components and existing protection settings. Then, the power of the electric arc flash will be evaluated using the suggested analytical-simulation-based method according to IEEE 1584 standard, followed by selection of proper protection devices settings for minimum arc power and risk for the staff.
关键词： DC-AC systems,incident energy,photovoltaics,protection devices,inverters,Arc flash
更新于2025-09-09 09:28:46
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A brief review of protection based routing and spectrum assignment in elastic optical networks and a novel p-cycle based protection approach for multicast traffic demands
摘要： The elastic optical network is one of the emerging technologies in the optical network paradigm, and it has been highlighted by many researchers in the past few years. So far, a comprehensive study has been conducted on routing and spectrum assignment in elastic optical networks. However, only a few works considered the problem of failure, protection, and recovery to enable seamless data transportation through the elastic optical networks. In this paper, we classify and review some different techniques to protect the traffic demands from failure and propose a p-cycle based protection approach for multicast traffic demands. A grooming technique is adopted and incorporated into the protection based techniques, to enhance the spectrum utilization efficiency by the traffic demands. We compare the proposed algorithm with some state-of-the-art protection based approaches. It is evident from the results that the proposed p-cycle based approach outperforms the other approaches concerning resources utilization ratio and execution time and grooming helps to reduce the spectrum resources required along with primary and backup resources. Finally, we discuss some of the important research areas, scope, and challenges which are relevant to protection and recovery based studies in elastic optical network paradigm.
关键词： protection,routing,elastic optical network,p-cycle,multicast,spectrum assignment,survivability
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - An Ultrafast Discrete Short-Circuit Protection Circuit for GaN HEMTs
摘要： Gallium Nitride enhancement-mode high electron mobility transistors (GaN E-HEMTs) are being designed into power electronic systems due to the fast switching capability. The GaN-based converters obtain higher efficiency, smaller size, and lower cost from the system point of view. On the other hand, the fast-switching characteristic of GaN also introduces the challenge of the short-circuit protection (SCP) and over-current protection (OCP). The traditional SCP/OCP methods are either too slow or not practical to the GaN device. Therefore, an alternative SCP/OCP solution which is fast and easy to implement is much desired for GaN HEMT. In this paper, an ultrafast discrete circuit of SCP for GaN HEMTs is proposed. The protection method includes two stages. The first-stage is soft turn-off, and the second-stage is hard turn-off. The soft turn-off can reduce the gate voltage gradually and thus limit the voltage spike on the DC-link. The method has been verified by both SPICE simulation and hardware implementation. The implementation results show that the propagation delay time for first-stage and second-stage are 85 ns and 125 ns, respectively. As a result, the proposed circuit is able to protect GaN HEMTs for short-circuit scenario under different DC-link voltages.
关键词： discrete circuit,short-circuit protection,GaN HEMT,gallium nitride
更新于2025-09-04 15:30:14
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[IEEE 2018 10th International Conference on Wireless Communications and Signal Processing (WCSP) - Hangzhou, China (2018.10.18-2018.10.20)] 2018 10th International Conference on Wireless Communications and Signal Processing (WCSP) - Privacy Protection via Beamforming Optimization in MISO NOMA Networks
摘要： Non-orthogonal multiple access is a promising approach for 5G. However, the privacy between users may be compromised due to the superposition of all users’ signals to successive interference cancellation (SIC) receivers. In this paper, we propose a scheme based on beamforming optimization for the downlink NOMA that can enhance the security of a speci?c private user while guaranteeing other users’ quality of service (QoS). Speci?cally, we intend to maximize the secrecy rate of the private user, under the constraint that the other users’ QoS is satis?ed. Owing to the non-convexity, we ?rst convert it into convex forms and then, an iterative algorithm based on the concave-convex procedure is proposed to attain their solutions. Extensive simulation results are presented to evaluate the effectiveness of the proposed scheme.
关键词： privacy protection,beamforming optimization,physical layer security,Non-orthogonal multiple access
更新于2025-09-04 15:30:14
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Color Build-Up and UV-protection Performance of Encapsulated Photochromic Dye-Treated Cotton Fabrics
摘要： A spirooxazine-based photochromic dye was encapsulated by an oil-in-water emulsion, solvent evaporation method. The encapsulated dye was applied to cotton fabric by a pad-cure process with different binder types. Ultraviolet (UV) protection was increased with application of the encapsulated photochromic dye. The type of binder used affected the photochromic color build-up during UV irradiation and could modify the UV protection imparted by the encapsulated photochromic dyes on textiles.
关键词： UV Protection,Binders,Photochromic Dyes,Encapsulation,Color
更新于2025-09-04 15:30:14
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[IEEE 2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM) - Split, Croatia (2018.9.13-2018.9.15)] 2018 26th International Conference on Software, Telecommunications and Computer Networks (SoftCOM) - Optimization of the Optical Power Budget for Various WDM-PON Network Designs with Traffic Protection Securing
摘要： For the expansion of WDM-PON networks, it is necessary to have a detailed knowledge of the optical power budget in all its parts. This contribution shortly analyses various WDM-PON network designs with the traffic protection securing utilized only passive optical components in remote nodes. A main part is focused on the optimization of optical power budget possibilities for considered WDM-PON network designs. For evaluation of optical power budgets, a simulation model related to WDM-PON network designs and to interactions between various metropolitan and access parts in the optical distribution network is realized in the Matlab programming environment.
关键词： optical power budget,WDM-PON network design,power splitter,traffic protection,optical add-drop multiplexor
更新于2025-09-04 15:30:14
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Refluxed Esterification of Fullerenes Conjugated P25 TiO2 Promotes Free Radical Scavenging Capacity and Facilitates Anti-aging Potentials in Human Cells
摘要： Titanium dioxide nanomaterials have good capability to prevent human cells from damage under UV irradiation. However, some studies indicated that the nanoscale of titanium dioxide could potentially cause harmful effects such as free radicals generation under UV irradiation and thereby accelerate the progress of cell aging. Fullerenes can scavenge large amounts of free radicals due to the fact that fullerenes contain enormous amount of π electrons with low lying lowest unoccupied molecular orbital (LUMO), but its adverse properties, such as the poor solubility in water, restricted the applicability. In this study, we employed water-soluble carboxylic acid fullerenes (C60-COOH and C70-COOH) as the free radical scavenger and modify onto the surface of titanium dioxide by refluxed esterification (P25/C60-COOH or C70-COOH) technique. The conformation and properties of theses nanomaterials were characterized by techniques and equipments such as X-ray diffraction (XRD), energy dispersive spectroscopy analysis (EDS), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), and Fourier transform infrared spectroscopy (FT-IR). We also introduced methylene blue (MB) and rhodamine B (Rh B) as indicator to evaluate and demonstrate the scavenging capacity of these nanomaterials. Moreover, we examined the biocompatibility and UV protection capacity of our P25/fullerene composites in human 293T cells, and applied luciferase activity assay to investigate the possible underlying cell protection mechanisms exhibited by these nanomaterials. Our data indicate that both P25/C60-COOH and P25/C70-COOH could protect human cells against UV exposure. P25/C70-COOH exhibits great anti-inflammation capacity, while as P25/C60-COOH exhibits great anti-oxidative stress and anti-DNA damage capacity. Our results suggest that most of our P25/fullerenes composite materials have the ability to reduce free radicals and exhibit high biomedical potential in anti-inflammation, anti-oxidant, and anti-aging applications.
关键词： refluxed esterification,anti-oxidative stress,UV protection,TiO2/fullerene composites,anti-inflammation
更新于2025-09-04 15:30:14
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - XGPON Statistical Multiplexing Analysis with Heterogeneous Users
摘要： Optical access networks are rapidly evolving mainly driven by the higher bandwidth requirements. XGPON is one of the most cost-effective solutions to upgrade existing GPON since it reuses existing optical distribution networks. Thanks to the high XGPON capacity, these networks can connect heterogeneous users such as base stations (BS), residential users (RU) or business users (BU). Statistical multiplexing of XGPON allows assigning different bandwidth to the different users based on their demands and always guaranteeing the agreed service level agreements. This work aims at evaluating the impact of packet delay and throughput for different XGPON scenarios for different user distributions. Furthermore, the paper evaluates the flexibility to cope with extra traffic caused by existing protection schemes.
关键词： DBA,network convergence,packet delay,XGPON,protection,throughput
更新于2025-09-04 15:30:14