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- 实验方案
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[IEEE 2019 Eleventh International Conference on Ubiquitous and Future Networks (ICUFN) - Zagreb, Croatia (2019.7.2-2019.7.5)] 2019 Eleventh International Conference on Ubiquitous and Future Networks (ICUFN) - Implement of 100-Gbps optical transceiver firmware for optical communication systems
摘要： This paper proposes a new fast technique, in which the slope of a photovoltaic (PV) inverter current is utilized to predict if the current is expected to exceed its rated value due to any grid faults. Two applications of this technique are demonstrated. In jurisdictions where grid codes require distributed generators (DGs) to disconnect after a fault occurrence, such as in Ontario, Canada, this technique is utilized to rapidly disconnect the PV solar system even before the inverter short circuit current actually exceeds the rated current of the inverter, thereby obviating the problem of any adverse short circuit current contribution into the grid. However, in regions where grid codes require DGs to stay connected and provide grid support, such as low-voltage ride through, this technique can be used to rapidly and autonomously transform the PV solar farm into a dynamic reactive power compensator STATCOM (termed PV-STATCOM) for providing voltage support function. In this paper, the PV-STATCOM is used to stabilize a critical induction motor load in the vicinity of the solar farm, which would have otherwise become unstable due to the grid fault. PSCAD-based simulation studies are performed on a realistic distribution network to demonstrate the effectiveness of this technique.
关键词： STATCOM,Distributed generator (DG),inverter,flexible AC transmission system (FACTS),protection,short circuit current,PV-STATCOM,photovoltaic (PV) systems
更新于2025-09-19 17:13:59
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Stable Lithium Deposition Enabled by Acid-Treated g-C3N4 Interface Layer for Lithium Metal Anode
摘要： Li metal has been regarded as one of the most promising anode candidates for high-energy rechargeable lithium batteries. Nevertheless, the practical applications of Li anode have been hampered because of its low coulombic efficiency and safety hazards. Here, acid-treated g-C3N4 with O- and N-containing groups is coated on Li foil through a facile physical pressing method. The O- and N-containing groups cooperate to rearrange the concentration of Li ions and enhance the Li ion transfer. Hence, the cycle and rate performances of acid-treated g-C3N4 coated Li electrodes are greatly improved in symmetric cells, which shows a stable cycling over 400 h at 1 mA cm-2 in ester-based electrolyte and over 2100 h in ether-based electrolyte. As for the Li//LiFePO4 full cells, there is a high capacity retention of 80% over 400 cycles at 1 C. The full cells of Li//S in ether-based electrolyte also exhibit a capacity of 520 mA h g-1 after 400 cycles at 1 C.
关键词： O-containing groups,Artificial protection layer,Li dendrites,Li metal anode,N-containing groups
更新于2025-09-19 17:13:59
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A Novel Symmetry Driven Siamese Network for THz Concealed Object Verification
摘要： This paper deals with those measures against overvoltage taken when protecting buildings occupied by people or animals. Such overvoltages can appear in the case of ground fault if the grounding system of the building is located within a potential funnel of a transmission tower's grounding system. This paper presents an entire concept regarding protection against any potential rise within the building. Computations of electrical potential on the grounding system having been performed using data obtained by measurements. This includes equipotential bonding, overvoltage protection of the building, and a transformer substation with metal–oxide varistors and gas-discharge arresters installed on the low-voltage line. A simulation model for the entire overvoltage protection based on known mathematical models has been merged within this paper. Adequate overvoltage protection elements were selected for protection against potential rises in the grounding systems of buildings on the basis of computation results.
关键词： grounding electrodes,grounding system,Gas-discharge arrester (GDA),metal-oxide varistor,overvoltage protection
更新于2025-09-19 17:13:59
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Green wavelength-tunable and high power Ho3+-doped upconversion fiber lasers
摘要： Biometrics is commonly used in many automated verification systems offering several advantages over traditional verification methods. Since biometric features are associated with individuals, their leakage will violate individuals’ privacy, which can cause serious and continued problems as the biometric data from a person are irreplaceable. To protect the biometric data containing privacy information, a number of privacy-preserving biometric schemes (PPBSs) have been developed over the last decade, but they have various drawbacks. The aim of this paper is to provide a comprehensive overview of the existing PPBSs and give guidance for future privacy-preserving biometric research. In particular, we explain the functional mechanisms of popular PPBSs and present the state-of-the-art privacy-preserving biometric methods based on these mechanisms. Furthermore, we discuss the drawbacks of the existing PPBSs and point out the challenges and future research directions in PPBSs.
关键词： automated verification system,biometric data,Privacy protection
更新于2025-09-19 17:13:59
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Quantum cascade laser lives on the edge
摘要： Electromagnetic waves with frequencies in the terahertz range (300?GHz to 10?THz) have applications in many areas, from imaging and security screening to the atmospheric and biological sciences. Semiconductor devices called quantum cascade lasers (QCLs) provide the most compact and efficient way to generate terahertz radiation. In QCLs, electrons cascade down in energy through a series of discrete quantum energy levels, emitting a photon at each step1. But, as with all compact semi conducting lasers, QCLs are notoriously sensitive to fabrication imperfections, which results in device-to-device variability of the laser output frequency. Now, on page 246, Zeng et al.2 report the realization of a terahertz QCL that is insensitive to such disorder. This achievement opens the door for terahertz lasers and optoelectronics that have unprecedented stability and fabrication reproducibility.
关键词： topological protection,terahertz radiation,topological insulators,photonics,quantum cascade lasers
更新于2025-09-19 17:13:59
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Nrf2 played an important role in radiation protection effect of low-level laser exposed on umbilical cord mesenchymal stem cell
摘要： To investigate the protective function of low-level laser irradiation (LLLI) against ionizing irradiation and explore the molecular mechanism of photomodulation of Nrf2 protein, the impact of LLLI (635 nm, 5.7 J/cm2) before 2 Gy gamma ray radiation of radio-sensitive tissue hematopoietic stem cells was evaluated. As a result, reduced levels of reactive oxygen species and increased expression of antioxidant enzymes were detected. Moreover, increased expression of Nrf2 was observed after LLLI, whereas brusatol pretreatment before LLLI abolished this effect. In vivo, transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) was employed for therapy of hematopoietic function in an acute radiation sickness (H-ARS) mouse model, which was induced by 6-Gy ionizing irradiation; different hUC-MSC pretreatments including LLLI and Nrf2 RNAi were accounted for during experimental grouping. LLLI treatment of cells significantly increased the erythrocyte count and number of myelopoiesis clones (P < 0.05), but such improvements were reduced by Nrf2 RNAi pretreatment compared with cells transplanted without intervention. Therefore, LLLI may improve the radiation protection effect through molecular mechanisms related to the Nrf2 antioxidant pathway.
关键词： Radiation protection,Nrf2,LLLI
更新于2025-09-19 17:13:59
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Silicon Waveguide Optically Tunable THz Filter
摘要： The Kirchhoff-Law-Johnson-Noise unconditionally secure key exchanger is a promising, surprisingly simple, very low cost and efficient electronic alternative to quantum key distribution. A few resistors, switches, and interconnecting cables can provide unconditionally secure data transmission in the ideal case by utilizing the thermal noise of the resistors. The key problems regarding practical realizations are related to the resistance tolerance, finite cable resistance, and other non-ideal properties that can cause information leak. In this paper, we present robust protection from cable resistance and resistance mismatch attacks against the system. Our theoretical results show that all resistive inaccuracies, parasitic resistances, cable resistance, and temperature dependence can be compensated; therefore, the practical implementation becomes much easier. The generalized method provides inherent protection against the so-called second law attack as well.
关键词： KLJN secure key exchanger,Unconditional security,attack protection,secure key exchange
更新于2025-09-19 17:13:59
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A Priority-Based Multiobjective Design for Routing, Spectrum, and Network Coding Assignment Problem in Network-Coding-Enabled Elastic Optical Networks
摘要： In elastic optical networks, the use of network coding (NC) represents a new dimension to further optimize spectrum efficiency, and indeed, combining NC and dedicated path protection has paved the way for achieving greater capacity efficiency, while retaining the merit of near-instantaneous recovery. In order to harness the NC benefits, a more complicated problem called routing, spectrum, and network coding assignment (RSNCA) has to be solved, and in this article, we propose a priority-based multiobjective design for the RSNCA problem aiming at maximizing the network throughput in the constrained bandwidth capacity and simultaneously minimizing the spectrum link usage for accepted demands. The multiobjective design is based on the weighting method, and we present a rigorous analysis on the impact of weight coefficients to the priority of constituent objectives. The efficacy of our design proposal is benchmarked with reference ones based on the traditional single-objective model and for both coding and non-coding approaches on various realistic topologies. It is highlighted that the application of NC brings about considerable throughput enhancement, and furthermore, the multiobjective RSNCA design is highly more efficient than the single-objective RSNCA, as up to more than 50% saving on spectrum link usage could be attained.
关键词： routing and spectrum assignment (RSA),elastic optical networks,network coding (NC),intelligent optical networks,integer linear programming,multiobjective optimization,Dedicated protection
更新于2025-09-16 10:30:52
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Donor–acceptor type black phosphorus nanosheets covalently functionalized with a conjugated polymer for laser protection
摘要： Covalent functionalization of two-dimensional black phosphorus (BP) with conjugated polymers would be favorable to improve its environmental stability and solubility in organic solvents, and thereby to open a way to explore more applications of BP in the fields of optoelectronics, electronics and photonics. As a proof-of-concept application, soluble donor–acceptor type BP nanosheets covalently functionalized with poly[(1,4-diethynyl-2,5-bis(hexyloxy)benzene)-alt-benzo[c]thiadiazole] (hereafter called PDBT-BP) were synthesized through Sonogashira–Hagihara coupling polymerization, and embedded into an optically nonactive transparent poly(methylmethacrylate) (PMMA) matrix to produce the PMMA-based PDBT-BP film for nonlinear optics. In contrast to BP/PMMA, PDBT-BP/PMMA and PDBT/BP blends/PMMA films, the annealed PDBT-BP/PMMA film, which was heated at 150 °C under dry argon for 1 h, shows more excellent reverse saturable absorption (RSA) behavior, with a larger nonlinear absorption coefficient (βeff ) of 208.16 cm GW?1 and an imaginary third-order susceptibility (Im χ(3)) of 8.89 × 10?11 esu at a pulse energy of 400 μJ. The achieved optical limiting (OL) threshold is 4.44 J cm?2 (0.74 GW cm?2), smaller than that of the non-annealed PDBT-BP/PMMA film (5.64 J cm?2). The SA (saturable absorption) to RSA transition observed at a low incident laser intensity could be used to realize all-optical intensity-dependent logic gates in the near future.
关键词： Conjugated Polymer,Laser Protection,Polymer Chemistry,Black Phosphorus,Nonlinear Optics
更新于2025-09-16 10:30:52
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High throughput procedure utilising chlorophyll fluorescence imaging to phenotype dynamic photosynthesis and photoprotection in leaves under controlled gaseous conditions
摘要： Background: As yields of major crops such as wheat (T. aestivum) have begun to plateau in recent years, there is growing pressure to efficiently phenotype large populations for traits associated with genetic advancement in yield. Photosynthesis encompasses a range of steady state and dynamic traits that are key targets for raising Radiation Use Efficiency (RUE), biomass production and grain yield in crops. Traditional methodologies to assess the full range of responses of photosynthesis, such a leaf gas exchange, are slow and limited to one leaf (or part of a leaf ) per instrument. Due to constraints imposed by time, equipment and plant size, photosynthetic data is often collected at one or two phenological stages and in response to limited environmental conditions. Results: Here we describe a high throughput procedure utilising chlorophyll fluorescence imaging to phenotype dynamic photosynthesis and photoprotection in excised leaves under controlled gaseous conditions. When measured throughout the day, no significant differences (P > 0.081) were observed between the responses of excised and intact leaves. Using excised leaves, the response of three cultivars of T. aestivum to a user—defined dynamic lighting regime was examined. Cultivar specific differences were observed for maximum PSII efficiency (Fv′/Fm′—P < 0.01) and PSII operating efficiency (Fq′/Fm′—P < 0.04) under both low and high light. In addition, the rate of induction and relaxation of non-photochemical quenching (NPQ) was also cultivar specific. A specialised imaging chamber was designed and built in-house to maintain gaseous conditions around excised leaf sections. The purpose of this is to manipulate electron sinks such as photorespiration. The stability of carbon dioxide (CO2) and oxygen (O2) was monitored inside the chambers and found to be within ± 4.5% and ± 1% of the mean respectively. To test the chamber, T. aestivum ‘Pavon76’ leaf sections were measured under at 20 and 200 mmol mol?1 O2 and ambient [CO2] during a light response curve. The Fv′/Fm′was significantly higher (P < 0.05) under low [O2] for the majority of light intensities while values of NPQ and the proportion of open PSII reaction centers (qP) were significantly lower under > 130 μmol m?2 s?1 PPFD. Conclusions: Here we demonstrate the development of a high-throughput (> 500 samples day?1) method for phenotyping photosynthetic and photo-protective parameters in a dynamic light environment. The technique exploits chlorophyll fluorescence imaging in a specifically designed chamber, enabling controlled gaseous environment around leaf sections. In addition, we have demonstrated that leaf sections do not different from intact plant material even > 3 h after sampling, thus enabling transportation of material of interest from the field to this laboratory based platform. The methodologies described here allow rapid, custom screening of field material for variation in photosynthetic processes.
关键词： Dynamic,Imaging,Phenotyping,Wheat,Photo-protection,Photosynthesis,Chlorophyll fluorescence
更新于2025-09-16 10:30:52