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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Proposal of Photonic Analog-to-digital Conversion Using Weighted Multiwavelength Pulses and Balanced Photodetector
摘要： Nowadays, enhanced knowledge of the nature of the electricity demand is achieved through the progressively increasing deployment of smart meters and advanced data analysis techniques. One of the major challenges is to exploit this knowledge to support the introduction of strategies to modify the demand according to relevant objectives to be achieved, like users’ participation in demand response programmes. A key point for facing this challenge is to characterize the demand flexibility. In spite of many discussions about the concept of flexibility, the few mathematical definitions of flexibility available do not address the variation in time of the overall demand aggregation. This paper starts from the analysis of time-variable patterns of aggregate residential customers, ending up with suitable definitions of expected flexibility for aggregate demand. These definitions are based on assessing positive and negative pattern variations and are identified from the analysis of the collective behavior of the aggregate users. A set of results is shown for different numbers of aggregate customers, by considering different values of the averaging time step for load pattern representation.
关键词： binomial probability,customers,demand flexibility,Aggregate demand,electrical load,demand response,load variation pattern,maximum likelihood estimation
更新于2025-09-23 15:21:01
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An Electrically Modulated Singlea??Color/Duala??Color Imaging Photodetector
摘要： An electrically modulated single-/dual-color imaging photodetector with fast response speed is developed based on a small molecule (COi8DFIC)/perovskite (CH3NH3PbBr3) hybrid film. Owing to the type-I heterojunction, the device can facilely transform dual-color images to single-color images by applying a small bias voltage. The photodetector exhibits two distinct cut-off wavelengths at ≈544 nm (visible region) and ≈920 nm (near-infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W?1 at ≈525 nm and 0.041 A W?1 at ≈860 nm with a fast response speed (≈102 ns). Under 0.6 V bias, the photodetector can operate in a single-color mode with a peak responsivity of 0.09 A W?1 at ≈475 nm, showing a fast response speed (≈102 ns). A physical model based on band energy theory is developed to illustrate the origin of the tunable single-/dual-color photodetection. This work will stimulate new approaches for developing solution-processed multifunctional photodetectors for imaging photodetection in complex circumstances.
关键词： organic/perovskite photodetectors,response speed,dual-color imaging
更新于2025-09-23 15:21:01
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Guanosine Assembly Enabled Gold Nanorods with Dual Thermo- and Photoswitchable Plasmonic Chiroptical Activity
摘要： Noble metal nanostructures with plasmonic circular dichroism (PCD) have attracted interest and a modulation of PCD is of great importance for their potential applications. Herein, we propose a supramolecular strategy for achieving dual thermal and photo-switchable PCD. When guanosine (G), deoxyguanosine (dG) and boric acid modified achiral gold nanorods (GNRs) were co-assembled into hydrogel, hybrid nanofibers with PCD were produced. When the hydrogel was heated, the nanofiber was disassembled and the PCD disappeared. Since the hydrogel was thermally reversible, a thermo-controlled PCD could be realized. The hybrid hydrogel also showed photo-switchable PCD. When the gel was irradiated with IR laser, the PCD disappeared. It can be restored by placing at room temperature. Moreover, the hybrid gel was selectively response to the circularly polarized light (CPL). For (G/dG)-GNRs hybrid assemblies, the R-CPL irradiation showed higher photothermal efficiency than that of L-CPL, which made it useful for an IR-irradiation controlled release of drug molecules.
关键词： plasmonic chirality,gold nanorods,guanosine,circular polarized light,selective response
更新于2025-09-23 15:21:01
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Effect of LED Radiation Pattern on BER Performance in Indoor Multipath MIMO-VLC System
摘要： The present paper investigates the impact of three radiation patterns of LED namely Lambertian, Batwing, Elliptical on the BER performance of 4 × 4 indoor multiple-input multiple-output (MIMO) visible light communication (VLC) system. The BER simulation has been done using LOS and LOS plus first reflection (L-R1) signals for ceiling-mounted and wall-mounted LEDs. For the case of ceiling-mounted LEDs, impulse response and BER have been computed using those radiation patterns at the centre and corner of a room (5 m × 5 m × 3 m). It has been found that LED having Elliptical radiation profile is more suitable for LOS signal when receiver is placed at the centre position whereas, Batwing radiation is suitable for L-R1 signal, both at the centre and corner positions. In the case of wall-mounted LEDs, impulse response and BER have been determined at the centre of the room using LOS and L-R1 signals. The results show that Batwing has least BER using LOS signal due to its wide radiation beam, but for L-R1 signal, the Elliptical profile having its narrow radiation beam has provided better BER performance. The present study shows that the BER in MIMO-VLC system not only depends on the transmitter and receiver position but also on the radiation patterns of LED and higher order reflection signals.
关键词： BER,MIMO,LED radiation pattern,VLC,Impulse response
更新于2025-09-23 15:21:01
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Long-Term Systemic Treatment With Methamphetamine Causes Retinal Damage in CD1 Mice
摘要： As a powerful psychostimulant with high potential for abuse, methamphetamine (Meth) could cause long-lasting abnormalities in retinas. The purpose of this study was to investigate the effects of systemic administration of Meth at low dose on retinal damage and understand the underlying mechanisms of pathology. CD1 mice were treated with 0.5 mg/kg or 1 mg/kg Meth by intra-peritoneal injection daily for 2 months, mice treated with saline were used as negative control. Electroretinography (ERG) reflects the mass response of photoreceptor cells and was used to test the outer retinal function after Meth treatment. Toluidine blue staining was used to show the retinal morphology and evaluate the photoreceptor cell loss. Inflammatory factors were measured by enzyme-linked immunosorbent assay to show the inflammatory response. Terminal deoxynucleotidyl transferase dUTP Nick end labeling assay was used to detect the apoptosis-positive cells. Real-time polymerase chain reaction and Western blot were applied to measure the gene and protein change to explore the underlying mechanisms. Results demonstrated that retinal damage was caused by Meth treatment after 2 months, evidenced by loss of rod photoreceptor cells; decreased ERG amplitude; increased apoptotic photoreceptor cells, cytochrome-c release, caspase-3 activity, caspase-9 activity, and apoptosis-related protein expression; increased malondialdehyde level as well as nicotinamide adenine dinucleotide phosphate oxidase 4 protein expression; decreased anti-oxidative agents glutathione as well as superoxide dismutase levels; and increased production and gene expression of inflammatory factors. Our study indicated that systemic administration of Meth caused neurotoxic effects on CD1 mouse retinas, providing the potential mechanisms for the retina damage caused by Meth abuse.
关键词： CD1 mice,retina damage,methamphetamine,inflammatory response
更新于2025-09-23 15:21:01
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AC Impedance Spectroscopy, Conductivity and Optical Studies of Sr doped Bismuth Ferrite Nanocomposites
摘要： Effect of Sr doping on the structural, optical, dielectric, impedance properties of citrate combustion reaction route prepared Bi1-xSrxFeO3 (BSFO) nanocomposite has been investigated. The study of Fourier Transform Infrared Spectroscopy confirms the formation of perovskite structure of the Sr doped bismuth ferrite samples. SEM analysis shows decrease in grain size with increasing Sr concentration in BSFO nanocomposite. UV–visible absorption spectra in the spectral range 1.0–3.5 eV showed two doubly degenerate d–d transitions and two charge transfer transitions and optical band gap is found to decrease from 2.14 to 2.05 eV with increasing Sr concentration. Studies of frequency and temperature dependences of dielectric permittivity, impedance and electric modulus of the materials in broad frequency (20 Hz- 1 MHz) and temperature (30o C – 500oC) ranges using a complex impedance spectroscopy technique have provided interesting information on the contribution of the microstructure in these parameters. It has been observed that dielectric constant and dielectric losses decreases as the doping of Sr increased from x=0.1 to x=0.3 and attained a maximum value for BSFO (x = 0.1) sample. Impedance analysis indicates the presence of grain (bulk) and grain boundary resistive contributions which are found to increase with the increased Sr content. The ac conductivity of the samples is found to be frequency and temperature dependent and also vary with extent of Sr doping in BFO. Charge transport through short as well as long range conduction contributions has been indicated in different temperature regions of conductivity studies.
关键词： dielectric response,complex impedance spectroscopy,microstructure,Bismuth ferrite
更新于2025-09-23 15:21:01
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A comprehensive study on the enhanced photocatlytic activity of a double-shell mesoporous plasmonic Cu@Cu2O/SiO2 as a visible-light driven nanophotocatalyst
摘要： A novel sunlight-activated double-shell Cu@Cu2O/SiO2 (m-pCu@Cu2O/SiO2) photocatalyst is presented via a combined precipitation and sol-gel methods with a mesoporous silica outer shell. After applying several characterization techniques on the m-pCu@Cu2O/SiO2, it was tested in the photodegradation of ciprofloxacin (CIP). The experimental results demonstrated a higher photocatalytic activity of the double-shell m-pCu@Cu2O/SiO2 nanophotocatalyst than the core-shell pCu@Cu2O nanophotocatalyst under the sunlight irradiation. When the content of pCu@Cu2O was 30 wt.%, it showed the highest activity. The Cu nanoparticles exhibited the surface plasmonic resonance (SPR) effect which increased the light absorption in the visible region of light. It also caused the rapid separation of the photoexcited e?/h+ pairs. Furthermore, the mesoporous structure of outer shell silica favors the transfer of reactants, resulting in the improved photoactivity performance for the supported pCu@Cu2O catalyst. Central composite design (CCD) based on RSM (response surface methodology) approach was used to optimize four of the most important experimental variables. The photodegraded intermediates were identified by HPLC-Mass.
关键词： Plasmonic,Response surface methodology,Ciprofloxacin,Mesoporous,Double-shell,Nanophotocatalyst
更新于2025-09-23 15:21:01
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Low-Power-Operating 3C-SiC Ultraviolet Photodetector fora?￡Elevated Temperature Applications
摘要： This work demonstrates the systematic investigation of the effects of high temperature on key performance parameters including speed, sensitivity, stability, and repeatability of a 3C-SiC/Si ultraviolet (UV) photodetector (PD) at various operating temperatures ranging from 50°C to 200°C. The device with very low dark current (≈ 0.08 pA) exhibited high sensitivity of 4466 and fast rise and decay times of 0.34 s and 0.30 s at 50°C to exposure of 254 nm UV light at a bias voltage of 20 V. Additionally, the device showed very good performance at a low operating voltage of 0.5 V and high temperature of 200°C, with a rise time of 2.68 s and decay time of 1.44 s, while maintaining good stability and repeatability. The slight decrease in performance (sensitivity from 4466 to 932) at 200°C was attributed to the increase in lattice scattering at elevated temperatures, leading to a decrease in carrier mobility. Moreover, the device was fabricated using a very cost-effective process flow. Consequently, this study can contribute to the development of low-power, fast, highly sensitive, and cost-effective 3C-SiC UVPDs for use in high-temperature photonic applications.
关键词： fast response,high sensitivity,High-temperature UVPD,low-voltage operation,3C-SiC
更新于2025-09-23 15:21:01
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Photocatalytic solar fuel production and environmental remediation through experimental and DFT based research on CdSe-QDs-coupled P-doped-g-C3N4 composites
摘要： Solar energy harvesting and conversion into useful chemical energy with the aid of semiconductor photocatalysts is a promising technique to solve both energy and environmental issues. This work reports a successful synthesis of CdSe quantum dots (QDs) modified phosphorus doped g-C3N4 (P-CN) for advanced photocatalytic applications. Phosphorus doping and structural coupling with CdSe QDs are shown to significantly extend visible-light response of g-C3N4 up to 700 nm. The optimized sample 4CdSe/P-CN demonstrates enhanced visible-light driven overall water splitting activities for H2 and O2 evolution i.e. 113 and 55.5 μmol.h?1.g?1, respectively, as well as very high photocatalytic CO2 to CH4 conversion efficiency (47 μmol.h?1.g?1). It also exhibit higher activity (78 %) for 2,4-dichlorophenol degradation as compared to pristine CN-sample. Combined photoluminescence, transient/single wavelength photocurrent, photoelectrochemical, and coumarin fluorescence spectroscopy demonstrate that 4CdSe/P-CN nanocomposite exhibit enhanced charge separation efficiency which is responsible for improved visible light catalytic activities. Our work thus provide a new strategy to design low-cost and sustainable photocatalysis with wide visible-light activity for practical overall water splitting and CO2 reduction applications.
关键词： Expending visible-light response,g-C3N4,Phosphorus doping,Solar fuel,CdSe quantum dots
更新于2025-09-23 15:21:01
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Faceta??Dependent, Fast Response, and Broadband Photodetector Based on Highly Stable Alla??Inorganic CsCu <sub/>2</sub> I <sub/>3</sub> Single Crystal with 1D Electronic Structure
摘要： Low-dimensional metal halides at molecular level, which feature strong quantum confinement effects from intrinsic structure, are emerging as ideal candidates in optoelectronic fields. However, developing stable and nontoxic metal halides still remains a great challenge. Herein, for the first time, high-crystalline and highly stable CsCu2I3 single crystal, which is acquired by a low-cost antisolvent vapor assisted method, is successfully developed to construct high-speed (trise/tdecay = 0.19 ms/14.7 ms) and UV-to-visible broadband (300–700 nm) photodetector, outperforming most reported photodetectors based on individual all-inorganic lead-free metal halides. Intriguingly, facet-dependent photoresponse is observed for CsCu2I3 single crystal, whose morphology consists of {010}, {110}, and {021} crystal planes. The on–off ratio of {010} crystal plane is higher than that of {110} crystal plane, mainly owing to lower dark current. Furthermore, photogenerated electrons are localized in twofold chains created by [CuI4] tetrahedra, leading to relatively small effective mass and fast transport mobility along the 1D transport pathway. Anisotropic carrier transport characteristic is related to stronger confinement and higher electron density for {110} crystal planes. This work not only demonstrates the great potential of CsCu2I3 single crystal in high-performance optoelectronics, but also gives insights into 1D electronic structure associated with fast photoresponse and high anisotropy.
关键词： photodetectors,facet-dependent photoresponse,1D electronic structures,highly stable,fast response
更新于2025-09-23 15:21:01