- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Application of Co-Mo bimetal/carbon composite in dye-sensitized solar cells and its research on synergy mechanism
摘要： Bimetal/carbon aerogels have many advantages, such as nano-scale properties, low density, large specific surface area, and high porosity, but their application in dye-sensitized solar cells (DSSCs) as a counter electrode (CE) instead of noble metal Pt is relatively rare. In this paper, a low-cost sodium alginate was used to obtain a Co-Mo bimetal/carbon composite through a simple and controlled carbonization process. Using them as CEs of ZnO-based DSSCs, the filling characteristics of dye can be effectively improved. When the Co2+/Mo2+ molar ratio is 1:3, the photoelectric conversion efficiency of Co-Mo bimetal/ carbon composite–based DSSCs is close to the photoelectric conversion efficiency of Pt based, which is considered to be the result of the synergy of the carbon and two metal ions.
关键词： Counter electrode,Bimetal/carbon composite,Synergy,Dye-sensitized solar cells,Aerogel
更新于2025-09-23 15:19:57
-
Separation of Si and SiC from Photovoltaic Industry Waste. Recycling of SiC in Production of Cu2O-SiC Powder
摘要： Silicon ingot cutting process generates slurry waste which mainly contains lubricant oil, silicon and silicon carbide particles. In this study, slurry waste was the subject of a primary decantation which served to obtain two different effluents namely dark sludge (DS) and dark liquid (DL). Deoiling treatment of DS and DL using acetone was carried out. The resulting powders were first leached by nitric acid to remove heavy metals and then washed by distilled water to separate Si and SiC. Scanning electron microscopy (SEM) coupled to energy dispersive x-ray spectrometry (EDXS) and x-ray diffraction (XRD) show a successful separation of Si and SiC particles. As reuse of SiC-rich powder, a Cu2O-SiC composite was synthesized by electroless plating process under experimental controlled parameters.
关键词： Composite,Silicon,Silicon carbide,Electroless plating,Slurry waste
更新于2025-09-23 15:19:57
-
Molecular States of Composite Fermions in Self-Organized InP/GaInP Quantum Dots in Zero Magnetic Field
摘要： The size and positions of regions of line localization and the magnetic-field (0–10 T) dependence of the low-temperature (10 K) photoluminescence spectra of single InP/GaInP quantum dots with a number of electrons of N = 5–7 and a Wigner–Seitz radius of ~2.5 are determined using a near-field scanning optical microscope. The formation of composite fermion molecules with a size coinciding with that of localization regions and bond lengths of ~30 and 50 nm, respectively, at a Landau-level filling factor from 1/2 to 2/7 in zero magnetic field is established. At N = 6, the pairing and rearrangement of composite fermions under photoexcitation are found, which offers opportunities for the use of InP/GaInP quantum dots to create a magnetic-field-free topological quantum gate.
关键词： InP/GaInP quantum dots,near-field scanning microscopy,photoluminescence,composite fermions,topological quantum gate
更新于2025-09-23 15:19:57
-
Dielectric Measurements of Polymer Composite Based on CdS Quantum Dots in Low Density Polyethylene at Microwave Frequencies
摘要： CdS nanoparticles (NPs) as quantum dots (QDs) added into low density polyethylene (LDPE) can significantly change the MW dielectric properties of the composites. Introducing into the matrix of low density polyethylene CdS QDs increase the dielectric constant of more than twice. CdS QDs with concentration of 5 wt % to 20 wt % were prepared by the method of high-speed thermal decomposition. The size of CdS nanoparticles ranged from 2 nm to 7 nm. Experimental samples based on polymer-based nanocomposite in the form of thick films with a thickness of 80 to 100 microns were prepared by thermocompression. Complex dielectric permittivity of thick film samples was measured by T/R method from 2 to 8 GHz at room temperature (25°C). For samples with 20 wt % CdS NPs size effect was found. The change of dielectric properties of polymer composite materials is associated with the size of QDs. The dielectric constant and dielectric loss increases with decreasing size of the quantum dots. It is shown that the highest mean value of the dielectric constant and dielectric loss at a frequency range of 5 GHz to 8 GHz for cadmium sulfide nanoparticles with size of 4 nm were 12 and 189 dB/m, respectively. For QDs with ones of 6 nm average dielectric constant and dielectric loss were 5.8 and 134 dB/m, respectively. The effective dielectric constant and dielectric losses in the microwave range can be changed by CdS QDs of different sizes what consequently increases the possibility of using polymer nanocomposites as core elements of the microwave band-pass filters for various purposes.
关键词： quantum dot,cadmium sulfide,polymer composite,filled polymer,MW dielectric properties,low density polyethylene,composites
更新于2025-09-23 15:19:57
-
Composite electrode of TiO2 particles with three kinds of crystal phases for significantly improved performance of dye-sensitized solar cells
摘要： A novel composite electrode of TiO2 particles with three kinds of crystal phases is fabricated for improving the dye-sensitized solar cell's performance. The photoelectric conversion efficiency of solar cell with the content of 30 wt% brookite nanocubes and 70 wt% P25 could reach 7.40%. It is obvious that brookite nanocubes are advantageous in terms of reduced charge recombination and higher voltage. On the other hand, P25 gives advantages of high surface area for dye loading and higher charge collection efficiency. This work shows a new photoelectrode design for enhanced energy conversion of DSSCs.
关键词： Composite electrode,Dye-sensitized solar cell,Brookite titania,Photoelectrochemcial property,Photovoltaic conversion efficiency
更新于2025-09-23 15:19:57
-
Optically active polymer nanocomposite composed of polyaniline, polyacrylonitrile and green-synthesized graphene quantum dot for supercapacitor application
摘要： Development of stable and optically active composite film that can show efficient supercapacitor activity is a challenging research interest in material science. A polymer nanocomposite film composed of a green synthesised graphene quantum dot (GQD, G) doped polyacrylonitrile (PAN) and polyaniline (PANI) systems, designated as PAN-PANI@G, have been prepared. The critical loading concentration of prepared composite and its effect on the physicochemical, optical and electrical analysis were systematically studied in detail. PAN-PANI@G composite showed an appreciable electrical conductivity (2.362 × 10?6 S m?1) and optical absorbance at λmax ~270 nm. Physicochemical characterizations by XRD, FTIR and TEM analysis reveal chemical interaction between the individual components via intermolecular hydrogen bonding. Analysed particle size of GQD in the polymer membrane was found to be about two times lesser than that of the pure GQD highlighting synergic interaction between the individual GQD and PAN/PANI matrix. A specific capacitance value of the polymer composites that have been modified on screen-printed carbon electrode were tested by cyclic voltammetric and galvanostatic charge-discharge techniques in 0.1 M H2SO4 solution. Calculated supercapacitor values at an applied current density, 670 mA g?1 are in a range of 105?587 F g?1 cm?2 which are approximately 2?1300 times higher than the values reported for polypyrrole and polyaniline based polymer composite film in the literature. As a preliminary extension of this study, the optimal PAN/PANI@G nanocomposite of GQD loading, 1.5 wt% was extended to prototype supercapacitor cell application in combination with a dilute solution of NaCl along with suitable conducting plates. When 3 V DC power was supplied for 4 min, the prototype cell produced an operating voltage of 1.4 V for 1 h of operating time.
关键词： Supercapacitor,Polyacrylonitrile-polyaniline composite,Prototype cell,Synergic interaction,Graphene quantum dots,IeV analysis
更新于2025-09-23 15:19:57
-
Graphene-Based Composite Right/Left-Handed Leaky-Wave Antenna at Terahertz
摘要： In this paper, a simple terahertz (THz) leaky-wave antenna (LWA) composed of periodic gapped graphene ribbons and a silicon substrate is presented. The graphene sheets of the antenna operate in an electric field with a resonance distribution of transverse electric (TE) surface plasmon polaritons (SPPs). The THz LWA has both negative and positive propagation constant with the variation of frequencies. Thus, the LWA performs as a composite right/left-handed (CRLH) LWA with backfire-to-endfire beam steering capability in the THz band. The working principle of the THz LWA is analyzed in detail using the theory of dispersion relation formulae and the equivalent CRLH circuit model. The THz LWA is verified by numerical simulations, and the frequency scannable capability of the THz LWA is confirmed. The proposed antenna has great potential applications for the THz LWA of the radiation capability in the entire upper quadrants.
关键词： Composite right/left-handed,Terahertz,Beam-steering,Graphene,Leaky-wave antenna
更新于2025-09-23 15:19:57
-
Efficiency Maximization for UAV-Enabled Mobile Relaying Systems with Laser Charging
摘要： One particular challenge in biomedical named entity recognition (NER) and normalization is the identification and resolution of composite named entities, where a single span refers to more than one concept (e.g., BRCA1/2). Previous NER and normalization studies have either ignored composite mentions, used simple ad hoc rules, or only handled coordination ellipsis, making a robust approach for handling multitype composite mentions greatly needed. To this end, we propose a hybrid method integrating a machine-learning model with a pattern identification strategy to identify the individual components of each composite mention. Our method, which we have named SimConcept, is the first to systematically handle many types of composite mentions. The technique achieves high performance in identifying and resolving composite mentions for three key biological entities: genes (90.42% in F-measure), diseases (86.47% in F-measure), and chemicals (86.05% in F-measure). Furthermore, our results show that using our SimConcept method can subsequently improve the performance of gene and disease concept recognition and normalization. SimConcept is available for download at: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/SimConcept/
关键词： composite mentions,text mining,coordination ellipsis,bioNLP,named entity recognition
更新于2025-09-23 15:19:57
-
Dynamics Modeling and Theoretical Study of the Two-Axis Four-Gimbal Coarsea??Fine Composite UAV Electro-Optical Pod
摘要： In the UAV electro-optical pod of the two-axis four-gimbal, the characteristics of a coarse–fine composite structure and the complexity of dynamics modeling affect the entire system’s high precision control performance. The core goal of this paper is to solve the high precision control of a two-axis four-gimbal electro-optical pod through dynamic modeling and theoretical study. In response to this problem, we used finite element analysis (FEA) and stress study of the key component to design the structure. The gimbals adopt the aerospace material 7075-t3510 aluminum alloy in order to meet the requirements of an ultralight weight of less than 1 kg. According to the Euler rigid body dynamics model, the transmission path and kinematics coupling compensation matrix between the two-axis four-gimbal structures are obtained. The coarse–fine composite self-correction drive equation in the Cartesian system is derived to solve the pre-selection and check problem of the mechatronic under high-precision control. Finally, the modeling method is substituted into the disturbance observer (DOB) disturbance suppression experiment, which can monitor and compensate for the motion coupling between gimbal structures in real time. Results show that the disturbance suppression impact of the DOB method with dynamics model is increased by up to 90% compared to PID (Proportion Integration Differentiation method) and is 25% better than the traditional DOB method.
关键词： dynamics modeling,coarse–fine composite,electro-optical pod,two-axis four-gimbal
更新于2025-09-23 15:19:57
-
Microstructure Influence of SACX0307-TiO2 Composite Solder Joints on Thermal Properties of Power LED Assemblies
摘要： The effect of the microstructure of solder joints on the thermal properties of power LEDs is investigated. Solder joints were prepared with different solder pastes, namely 99Sn0.3Ag0.7Cu (as reference solder) and reinforced 99Sn0.3Ag0.7Cu–TiO2 (composite solder). TiO2 ceramic was used at 1 wt.% and with two different primary particle sizes, which were 20 nm (nano) and 200 nm (submicron). The thermal resistance, the electric thermal resistance, and the luminous efficiency of the power LED assemblies were measured. Furthermore, the microstructure of the different solder joints was analyzed on the basis of cross-sections using scanning electron and optical microscopy. It was found that the addition of submicron TiO2 decreased the thermal and electric thermal resistances of the light sources by 20% and 16%, respectively, and it slightly increased the luminous efficiency. Microstructural evaluations showed that the TiO2 particles were incorporated at the Sn grain boundaries and at the interface of the intermetallic layer and the solder bulk. This caused considerable refinement of the Sn grain structure. The precipitated TiO2 particles at the bottom of the solder joint changed the thermodynamics of Cu6Sn5 formation and enhanced the spalling of intermetallic grain to solder bulk, which resulted in a general decrease in the thickness of the intermetallic layer. These phenomena improved the heat paths in the composite solder joints, and resulted in better thermal and electrical properties of power LED assemblies. However, the TiO2 nanoparticles could also cause considerable local IMC (Intermetallic Compounds) growth, which could inhibit thermal and electrical improvements.
关键词： power LED,SAC composite alloy,TiO2 ceramic,luminous efficiency,thermal resistance,microstructure characterization
更新于2025-09-23 15:19:57