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Enhanced absorption of monolayer molybdenum disulfide (MoS2) using nanostructures with symmetrical cross resonator in the visible ranges
摘要： In order to enhance the absorption of monolayer molybdenum disulfide (MoS2), a novel nanostructure with symmetrical cross resonator based on MoS2 in the visible wavelength ranges has been proposed. At a resonant wavelength of 623 nm, the absorption of monolayer MoS2 in the absorption structure is as high as 82%, much higher than the bare MoS2 in the air. The electric field around monolayer MoS2 is enhanced by the guided mode resonance, thereby enhancing the absorption of monolayer MoS2 in the structure. The relevant parameters of the proposed structure are adjusted to achieve the tunability of the resonant wavelength in the visible ranges and the high-efficiency absorption of monolayer MoS2 in the structure, which is of great significance for the applications of MoS2-based optoelectronic devices.
关键词： Absorption,Monolayer MoS2,Perfect absorption structure,Resonance
更新于2025-09-23 15:23:52
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Ultra-sensitive surface plasmon resonance biosensor based on MoS2–graphene hybrid nanostructure with silver metal layer
摘要： The optical biosensors based on the plasmonic technology are an important research item in the field of biophotonics. The graphene–molybdenum disulfide (MoS2) based hybrid structures are very effective in designing and fabricating of the sensitive optical biosensors. In this paper, we propose a nanostructure Ag/MoS2/graphene as an optical biosensor with high performance and sensitivity. The proposed configuration for this surface plasmon resonance (SPR) optical biosensor is Kretschmann. Herein, the enhancement of sensitivity for the proposed SPR optical biosensor is investigated in different states. By determining of the numbers of MoS2 layer and the thickness of the metal layer, we increased the sensitivity of the proposed biosensor. The maximum sensitivity ~ 190°/RIU is achieved. For this ultra-sensitive SPR biosensor with maximum sensitivity, the numbers of MoS2 and graphene layer is 2 and the resonance wavelength is determined 680 nm.
关键词： Surface plasmon resonance,Molybdenum disulfide,Biosensor,Sensitivity,Graphene
更新于2025-09-23 15:23:52
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Positron emission tomography/computed tomography outperforms MRI in the diagnosis of local recurrence and residue of nasopharyngeal carcinoma: An update evidence from 44 studies
摘要： Studies on nasopharyngeal carcinoma (NPC) in five electronic databases were systematically searched online from the inception to June 5, 2018. Quality of the included studies was assessed using the updated Quality Assessment of Diagnostic Accuracy Studies 2. Data of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the 95% confidence intervals were pooled using a bivariate random‐effect model. Forty‐four studies with 61 groups of data and totally 3369 patients were included in the qualitative and quantitative synthesis analysis. The overall estimated sensitivity and specificity of positron emission tomography/computed tomography/magnetic resonance imaging (PET‐CT/MRI) for local recurrent/residual NPC were 0.90 and 0.85, respectively. The pooled area under the curve of (AUC) of PET‐CT/MRI in the summary receiver operator characteristic curve was 0.94. Subgroup analysis showed MRI vs PET‐CT had lower sensitivity (0.83 vs 0.92) and specificity (0.78 vs 0.89). The AUCs of MRI and PET‐CT were 0.87 and 0.96, respectively. No‐cross of 95% CI was found in MRI vs PET/CT (0.87‐0.90 vs 0.94‐0.98). Meta‐regression showed PET/CT vs MRI was a potential source of heterogeneity. PET/CT and MRI both showed quite high overall ability in diagnosing local recurrent/residual NPC, but the subgroup analysis indicated PET‐CT was superior over MRI in diagnosis of local recurrence and residue of NPC after radiotherapy. The examination methods affected the heterogeneity within studies.
关键词： specificity,positron emission tomography/computed tomography,sensitivity,magnetic resonance imaging,recurrence/residue,nasopharyngeal carcinoma
更新于2025-09-23 15:23:52
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Self-electrochemiluminescence of poly[9,9-bis(3‘-(N,N- dimethyl amino)propyl)-2,7-fluorene]-alt- 2,7-(9,9- dioctylfluorene)] and resonance energy transfer to aluminum tris(8-quinolinolate)
摘要： In this paper, the electrochemiluminescence (ECL) behavior of a hole-transport polymer, poly [9,9-bis(3'-(N,N-dimethylamino) propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)] (PFN) was examined with the purpose of finding a novel organic ECL emitter. It was found that the PFN exhibits self-electrochemiluminescence (self-ECL) without any exogenous co-reactants. Quite different from the traditional ECL, the addition of tripropyl amine (TPA) quenched the self-ECL of PFN. PFN ECL intensity reaches a peak during electrochemical oxidation process due to the superposition of self-enhanced ECL, and aggregation quenching of excited state by PFN excimer formation. Aluminum tris(8-quinolinolate) (AlQ3) doped with PFN recovers luminescence intensity with restraining quenching effect via ECL resonance energy transfer from PFN to AlQ3, giving rise to a stable luminescence signal, and hence sensory detection of nitroaromatics. The limits of detections for nitroaromatics can reach down to a level of 10^-22 M. This work sets the stage for a novel organic polymer-based ECL emitter without using any toxic exogenous co-reactant, and presents a practical avenue for a prototype of realising sensory detection through signal stabilization via energy resonance energy transfer (ERET).
关键词： poly[9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene),Sensor,Resonance energy transfer,Self-electrochemiluminescence
更新于2025-09-23 15:23:52
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New trends of gyrotron development at KIT: An overview on recent investigations
摘要： Since many years KIT is strongly involved in the development of high power gyrotrons for use in ECRH. KIT is pursuing two development lines: (i) the conventional, hollow cavity gyrotron and (ii) the coaxial cavity gyrotron. KIT is pushing conventional cavity gyrotrons from 1 MW to 1.5 MW in a common project with IPP Greifswald. Coaxial cavity technology having the advantage of higher power capability, in particular at higher frequency, is used for the 2 MW 170 GHz short-pulse prototype. This gyrotron is currently being upgraded to allow pulse extension up to approximately 100 ms and up to 1 s in a second step. For a future DEMOnstration fusion power plant two challenging trends with respect to gyrotron features are recognized: (a) the operating frequency will be above 200 GHz and (b) the requested total efficiency of the gyrotron should be higher than 60%. KIT is addressing these requirements by investigating both gyrotron technologies for their performance at a frequency well above 200 GHz. We started careful analysis of multi-staged-depressed collectors.
关键词： Electron-cyclotron-resonance heating and current drive,Gyrotron,Coaxial cavity,Magnetron injection gun
更新于2025-09-23 15:23:52
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Control of plasmon dephasing time using stacked nanogap gold structures for strong near-field enhancement
摘要： The construction of metallic nanostructures with strong near-field enhancement is becoming increasingly significant for the practical use of plasmonic devices, such as plasmonic sensors and light-energy conversion systems. Importantly, the near-field enhancement effect depends on the plasmon dephasing time. Here, we propose a method for controlling plasmon dephasing time by utilizing plasmonic coupling for stronger near-field enhancement. Ordered arrays of stacked nanogap gold (Au) structures composed of a metal/insulator/metal nanostructure were fabricated by electron beam lithography and dry etching processes on a niobium-doped titanium dioxide substrate. The dark plasmon mode was excited by the near-field coupling between the upper and lower Au nanostructures separated by an alumina layer with a thickness of 15 nm. A strong near-field enhancement effect was induced by the localization of the electromagnetic field between the upper and lower Au nanostructures and the longer plasmon dephasing time based on the excitation of the dark plasmon mode. It is noteworthy that the dephasing time of the dark plasmon mode measured by time-resolved photoemission electron microscopy was extended 3-fold compared with that of the plasmon mode of the Au nanoblock, which can be controlled by the structural design of the stacked nanogap Au structures.
关键词： Dark plasmon mode,Plasmon dephasing,Near-field enhancement,Photoemission electron microscopy (PEEM),Surface plasmon resonance
更新于2025-09-23 15:23:52
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Phononic Casimir corrections for Graphene resonator
摘要： By calculating a Casimir energy for the acoustic phonons of Graphene, we find some temperature-dependent corrections for the pretension of a Graphene sheet suspended on a trench. We obtain values of the order of few mN/m for these corrections in fully as well as doubly clamped Graphene on a narrow trench with one nanometer width, at room temperature. These values are considerable compared to the experimental values, and can increase the fundamental resonance frequency of the Graphene. The values of these corrections increase by increasing the temperature, and so they can be utilized for tuning the Graphene pretension.
关键词： Resonance frequency,Graphene sheet,Casimir energy,Acoustic phonons,Pretension,Nanoelectromechanical systems
更新于2025-09-23 15:23:52
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Gold Nanorod-Coated Capillaries for the SERS-Based Detection of Thiram
摘要： Surface enhanced Raman scattering (SERS)-based capillary system is a promising route towards fast, real-time and in-situ detection using a facile sampling process. Here, we demonstrate for the first time resonance-tunable SERS-active capillaries with high sensitivity, reproducibility and stability. The strong signal consistency independent of measurement spots or storage time supports the long-term storage and signal tracking of analytes in practical use. The capillaries were successfully applied to the in-situ detection of pesticide residues, and the sampling process provides operation conveniency compared to conventional methods. These results indicate that our SERS-active capillaries have great potentials in fast in-situ detection for many practical applications.
关键词： surface enhanced Raman scattering,stability,thiram detection,gold nanorod,capillary tube,tunable plasmon resonance
更新于2025-09-23 15:23:52
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[IEEE 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Erlagol (Altai Republic), Russia (2018.6.29-2018.7.3)] 2018 19th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - The System of Frequency Matching of the Ultrasonic Generators with the Radiators in “Bulava” Apparatuses
摘要： The article is devoted to the problem concerned with the determination of resonance frequency of the ultrasonic vibrating systems (the radiators) intended for the operation as a part of the ultrasonic technological apparatuses of “Bulava” type.
关键词： frequency control system,generator,resonance matching,Ultrasound
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Kiev (2018.7.2-2018.7.5)] 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET) - Electromagnetic Scattering of THz Waves from a Microsize Graphene-Sandwiched Thin Dielectric Strip
摘要： Two-dimensional (2-D) scattering of the H-polarized plane wave by a composite flat material strip is investigated. It is made as graphene-dielectric-graphene sandwich-like structure which is placed in the free space. Our modeling uses singular integral equations and Nystrom discretization. The scattering cross-section and the absorption cross-section are computed, together with the relative error plots for the current and the far field. The surface plasmon resonances on the graphene strips and the thin dielectric layer performance are evaluated.
关键词： strip,electromagnetic scattering,resonance
更新于2025-09-23 15:23:52