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Performance optimization of complicated structural SiC/Si composite ceramics prepared by selective laser sintering
摘要： Combining reaction-bonded (RB) process and selective laser sintering (SLS) method is an e?ective approach to prepare ceramic components with complex shapes. The purpose of this paper is to ?nd e?cient ways to improve the performance of SiC/Si composites prepared by SLS/RB technologies. E?ects of epoxy resin binder on the performance and microstructure of preforms and sintered bodies were studied ?rst. Then, based on the above results, graphite with low reactivity was used as an alternative slow-release carbon source to promote sintering densi?cation process and improve the carbon density of preforms. When the added amount of graphite increased, clusters of nanometer-sized SiC grains formed and the silicon phase transformed into pieces, which reduced the content and dimension of silicon phase. Furthermore, by applying a two-step sintering method, the residual silicon content of SiC/Si composites decreased further and the ?exural strength at high temperatures increased.
关键词： Performance enchantment,High-temperature behavior,Selective laser sintering,Reaction-bonded process
更新于2025-09-12 10:27:22
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Thermal and electrical behavior of built-middle photovoltaic integrated Trombe wall: experimental and numerical study
摘要： This study proposed a new system with the photovoltaic (PV) panel installed in the middle of channel of the Trombe wall (TW) system, called as built-middle photovoltaic integrated Trombe wall (PVMTW), which can realize multiple functions of electricity generation, space heating and heat preservation. The experiment rig was built to study the temperature field of the PVMTW system in heating seasons, in Hefei. A mathematical model of the PVMTW system was developed and validated against experimental data. Using the validated model, the thermal performance of the PVMTW system was investigated by comparison with that of the classic Trombe wall. The results showed that in the daytime, the average thermal efficiency of the PVMTW system was 65.2% higher than that of the classic TW system. In terms of room air temperature and interior surface temperatures on the walls, the indoor thermal comfortable of the PVMTW system was almost the same as that of the classic TW system. The average predicted mean vote (PMV) for two rooms (room with the PVMTW system and room with the classic TW system) were 0.05 and -0.36, respectively. Additionally, the average electrical efficiency and average total efficiency achieved 0.120 and 0.585, respectively.
关键词： PMV index,PV Trombe wall,Electrical performance,Total efficiency,Thermal comfort
更新于2025-09-12 10:27:22
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Optimizing Graphene Content in NiSe/Graphene Nanohybrid Counter Electrode on Boosting Photovoltaic Performance of Dye-sensitized Solar Cells
摘要： Nickel selenide (NiSe) nanoparticles were grown onto different mass ratios of graphene nanosheets (GN) to get their corresponding NiSe/GNx (x= 0.25 to 1.00) nanohybrids by a facile in-situ hydrothermal process to integrate the advantages of high specific surface area of graphene and homogeneously immobilized catalytic sites of NiSe. The nanohybrid having the mass ratio of 1:0.50 (i.e., NiSe/GN0.50) exhibited a higher electrocatalytic activity and electrolyte diffusion. Thus, NiSe/GN0.50 exhibited an improved photo-conversion efficiency (PCE) of 12% (? = 8.62%) than the standard Pt (? = 7.68%) based dye-sensitized solar cell (DSSC). This improved PCE mainly originated from the catalytic ability of NiSe and the multiple interfacial electron transfer pathway of graphene, resulting in the enhanced charge transfer and fast tri-iodide reduction kinetics at the counter electrode/electrolyte interface. The results obtained from the cyclic voltammetry (CV), electrochemical AC-impedance (EIS) and Tafel polarization studies validated the synergistic effect of NiSe and GN and the high possibility of this nanohybrid as an efficient counter electrode (CE) for DSSC.
关键词： Photovoltaic performance,Counter electrode,Graphene nanosheets,Nickel selenide,Dye-sensitized solar cell
更新于2025-09-11 14:15:04
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Highly efficient perovskite solar cell utilizing a solution-processable tetrabenzoporphyrin hole transport material with p-type dopants
摘要： We demonstrate an efficient hole transporting material (HTM), soluble non-peripherally substituted octahexyl tetrabenzoporphyrin (C6TBPH2), for perovskite solar cells and determine the role of p-type dopants in improving the photovoltaic performance of devices utilizing this C6TBPH2 HTM. By adding p-type dopants, the fill factor and short-circuit current density under a reverse bias scan are improved from 0.20 ± 0.02 to 0.66 ± 0.03 and from 15 ± 2 to 20.8 ± 0.1 mA cm?2, respectively, due to formation of oxidized C6TBPH2 radical cations. Hence, the devices utilizing C6TBPH2 HTM achieve power conversion efficiencies of 15.2%, which are comparable with devices utilizing commercial HTMs fabricated under similar conditions.
关键词： perovskite solar cell,hole transport material,tetrabenzoporphyrin,photovoltaic performance,p-type dopants
更新于2025-09-11 14:15:04
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Red‐Blood‐Cell Waveguide as a Living Biosensor and Micromotor
摘要： The changes of flavor components during boiling in Lentinus edodes were studied by high-performance liquid chromatography and gas chromatography-mass spectrometry in this article. Results showed that nonvolatile flavor components in L. edodes gradually transferred into the soup during boiling. Contents of nonvolatile flavor substances in the soup increased significantly (p < .05) compared with the preboiling period (15 minutes) and gradually maintained a balanced situation with the boiling time extended. During boiling, content of alcohols gradually reduced, especially the content of 1-octen-3-ol, which is a typical flavor component in L. edoedes. The contents of sulfur compounds, aldehydes, and hydrocarbons increased first and finally decreased gradually with the boiling time extended. Therefore, the changes of flavor components in the soup almost maintained a balanced situation with the boiling time from 30 to 60 minutes. The results of this article could provide a theoretical basis for the changes of flavor compounds in L. edodes during boiling.
关键词： flavor components,gas chromatography–mass spectrometry,High-performance liquid chromatography,boiling,Lentinus edodes
更新于2025-09-11 14:15:04
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Halogenated Antimonene: One‐Step Synthesis, Structural Simulation, Tunable Electronic and Photoresponse Property
摘要： Surface functionalization is considered to be an effective and versatile strategy to tailor intrinsic electronic and optoelectronic properties of 2D materials. In this work, surface-decorated few-layer antimonene is synthesized by a one-step electrochemical exfoliation and synchronous halogenation method in halogen-containing an ionic liquid–based electrolyte at room temperature. The prepared halogenated antimonene nanosheets are composed of oxygen- and halogen-decorated amorphous and crystalline domains. The structural reconstructions and evolutions of halogenated antimonene are further revealed by ab initio molecular dynamics simulations and first-principles calculations. The band structures and optical properties of antimonene can be tailored after amorphization and surface functionalization, depending on the reactivity of different halogens. The photoresponse performance of the halogenated antimonene is further evaluated by photoelectrochemical measurement. Exhibiting self-powered photoresponse behavior, their photocurrent density increases with the increases of external bias potential and light intensity. This work proposes a new idea of tuning the optoelectronic properties of 2D materials by synchronous halogenation in the facile one-step electrochemical synthesis process. Benefiting from this facile synthesis procedure, the halogenation of antimonene may shed light on chemical functionalization of other 2D materials for electronic and optoelectronic applications.
关键词： photoresponse performance,halogenation,antimonene,DFT calculations,2D materials
更新于2025-09-11 14:15:04
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Facile preparation and properties of polyvinylidene fluoride dielectric nanocomposites <i>via</i> phase morphology control and incorporation of multiwalled carbon nanotubes conductive fillers
摘要： A novel PVDF dielectric nanocomposite was achieved by controlling phase morphology and incorporating conductive ?llers simultaneously, and the mechanical, thermal, dielectric properties of the resultant dielectric nanocomposites were investigated. Mechanical analysis showed that incorporation of modi?ed MWCNTs (MWCNTs-COOH) in the PVDF nanocomposites resulted in signi?cant improvements on the tensile strength (Ts) and elasticity modulus (Em). When the ?ller content was 12 wt%, the Ts of MWCNTs-COOH/PVDF could reach 64.6 MPa. XRD test showed that the addition of MWCNTs-COOH and MWCNTs promoted the formation of β-phase of PVDF. DMA analysis showed that the glass-transition temperature of the PVDF nanocomposites slightly increases on loading of original MWCNTs and this effect was more pronounced on loading MWCNTs-COOH. The dielectric property analysis showed that the original MWCNTs were more likely to form local conductive networks in the PVDF matrix, promoting the electron displacement polarization, and improving the dielectric constant. When the contents of MWCNTs was 12 wt%, the percolation threshold was obtained and the dielectric constant (ε0) reached 286, which was 36 times of pure PVDF. Our work provides a simple way to fabricate polymer blends with excellent dielectric performances, good mechanical properties as well as good processing capability but low cost.
关键词： polyvinylidene ?uoride (PVDF),thermal performance,dielectric properties,multi-walled carbon nanotubes (MWCNTs),mechanical properties
更新于2025-09-11 14:15:04
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Creating an antibacterial surface on beta TNZT alloys for hip implant applications by laser nitriding
摘要： The National Joint Registry reported that the main causes for hip implant revision surgery include aseptic loosening, infection and adverse soft tissue reaction to particulate debris. There is a great need to improve the implant properties which can be achieved through a combined solution of beta titanium alloy (TNZT) with low elastic modulus and laser surface nitriding to improve mechanical properties and biological response. While titanium nitride (TiN) possesses good biocompatibility and remarkable antibacterial properties; its effectiveness as a coating on Ti-35Nb-7Zr-6Ta has not been investigated in relation to stem cell response and antibacterial laser power, specifically 35, 40 and 45 W. capability. TNZT surfaces were laser-nitrided in incremental Investigation included surface roughness and topography in microscale (WLI and SEM), microstructure (XRD) and wettability (water contact angle). Biological studies of the laser-nitrided surfaces included in vitro culture for 24 h using mesenchymal stem cell (MSC) fluorescence staining and Staphylococcus aureus (S. aureus) Live/Dead staining. Sample groups consisted of control base metal (BM), laser-nitrided at 35 W (LT35), 40 W (LT40) and 45 W (LT45). Results revealed that laser nitriding generates significantly rougher surfaces (Ra value of BM was 199.3 nm, LT35 was 722.8 nm, LT40 was 458.4 nm and LT45 was 1180.2 nm) with distinctive surface features (Rsk < 0 and Rku > 3). Surfaces after laser nitriding, regardless of laser power, can be tailored to become hydrophilic (27.1–34.2°). Fibre laser nitriding can be used to create antibacterial surface patterns on TNZT in a high power regime. A laser power of 45 W proved to be the most effective in this study, creating an overlapping crescent shape which becomes more obvious with increasing power. To summarise, laser-nitrided surfaces led to a significant antibacterial effect but offered no particular advantage to MSC response.
关键词： Fibre laser nitriding,TNZT,Antibacterial performance,Mesenchymal stem cell (MSC),Beta titanium
更新于2025-09-11 14:15:04
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Controlling Surface Chemical Heterogeneities of Ultrasmall Fluorescent Core–Shell Silica Nanoparticles as Revealed by High-Performance Liquid Chromatography
摘要： Ultrasmall (diameter below 10 nm) fluorescent core?shell silica nanoparticles have garnered increasing attention in recent years as a result of their high brightness and favorable biodistribution properties important for applications including bioimaging and nanomedicine. Here, we present an in-depth study that provides new insights into the physical parameters that govern full covalent fluorescent dye encapsulation within the silica core of poly(ethylene glycol)-coated core?shell silica nanoparticles referred to as Cornell prime dots (C′ dots). We use a combination of high-performance liquid chromatography (HPLC), gel-permeation chromatography, and fluorescence correlation spectroscopy to monitor the result of ammonia concentration in the synthesis of C′ dots from negatively and positively charged versions of near-infrared dyes Cy5 and Cy5.5. HPLC, in particular, allows the distinction between cases of full versus partial dye encapsulation in the silica particle core leading to surface chemical heterogeneities in the form of hydrophobic surface patches, which, in turn, modulate biological response in ferroptotic cell death experiments. Our results demonstrate that there is a complex interplay between dye?dye and dye?silica cluster interactions originally formed in the sol?gel synthesis governing optimal dye encapsulation. We expect that the reduced surface chemical heterogeneities will make the resulting nanoparticles attractive for a number of applications in biology and medicine.
关键词： gel-permeation chromatography,ferroptotic cell death,high-performance liquid chromatography,fluorescent core?shell silica nanoparticles,fluorescence correlation spectroscopy
更新于2025-09-11 14:15:04
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Performance ratio prediction of photovoltaic pumping system based on grey clustering and second curvelet neural network
摘要： Performance ratio is an important parameter of measuring the quality and efficiency of photovoltaic (PV) pumping system, which should be predicted correctly to provide guidance for regulating the measurements of reducing losses of every part, therefore this research proposed a prediction model of performance ratio of PV pumping system based on grey clustering and second curvelet neural network. The meaning of performance ratio is analyzed and the main affecting factors of the performance level for PV pumping system are also summarized. The second curvelet neural network is constructed combing the second curvelet transform and feed forward neural network, and the structure of second curvelet neural network is designed. The classification of training and testing samples are confirmed based on the improved grey clustering model, and the corresponding mathematical models are studied. The firefly algorithm is used to optimize the second curvelet neural network. The grey classifications of training samples are confirmed based on grey clustering, which are used to train the second curvelet neural network with different structure optimized by firefly with different parameters, and then the testing samples are used to carry out prediction analysis. Simulation results show that the second curvelet neural network has highest prediction precision and efficiency, which can correctly and efficiently predict the performance ratio of PV pumping system.
关键词： Performance ratio,PV pumping system,Second curvelet neural network,Grey clustering
更新于2025-09-11 14:15:04