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Efficacy of erbium-doped yttrium aluminum garnet laser with casein phosphopeptide amorphous calcium phosphate with and without fluoride for remineralization of white spot lesions around orthodontic brackets
摘要： Objective: This study aimed to assess the efficacy of erbium?doped yttrium aluminum garnet (Er:YAG) laser, pastes containing casein phosphopeptide amorphous calcium phosphate (CPP?ACP) with and without fluoride and their combination for prevention of white spot lesions in the enamel. Materials and Methods: This in vitro experimental study was conducted on 90 extracted sound premolars. The teeth were then randomly divided into six groups of 15: (1) Control, (2) laser, (3) CPP?ACP with fluoride (GC MI Paste, Recaldent? 900 ppm as NaF), (4) CPP?ACP without fluoride (GC Tooth Mousse Recaldent?), (5) laser + CPP?ACP with fluoride, and (6) laser + CPP?ACP without fluoride. In each group, enamel surface was exposed to the remineralizing agent. The teeth were then subjected to pH cycling for 14 days. The teeth were then sectioned, polished, and underwent cross?sectional microhardness testing at 20–160 μ depth quantitatively. Using the Simpson’s rule, the amount of mineral loss was calculated in each group. Statistical Analysis Used: ANOVA was used for the comparisons, and Tukey’s test was applied for pairwise comparisons. Results: The highest mean volume percentage of microhardness at 20–60 μ depth belonged to the group laser + CPP?ACP with fluoride and the lowest belonged to the control group (P = 0.001). The differences were not significant at 80?120 μ depth (P > 0.05). These finding are confirmed according to ?Z (mineral loss). Conclusion: Based on these results, Er: YAG laser was able to decrease demineralization and was a potential alternative to preventive dentistry and was more effective when combined with CPP?ACP products.
关键词： Casein phosphopeptide amorphous calcium phosphate,white spot lesion,erbium-doped yttrium aluminum garnet laser
更新于2025-09-11 14:15:04
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Phosphate-passivated SnO2 Electron Transport Layer for High Performance Perovskite Solar Cells
摘要： Tin oxide (SnO2) is widely used in perovskite solar cells (PSCs) as an electron transport layer (ETL) material. However, its high surface trap density has already become a strong factor of limiting PSC development. In this work, phosphoric acid is adopted to eliminate the SnO2 surface dangling bonds to improve electron collection efficiency. The phosphorus mainly exists at the boundaries in the form of chained phosphate groups, bonding with which more than 47.9% of Sn dangling bonds are eliminated. The reduction of surface trap states depresses the electron transport barriers, thus the electron mobility increases about 3 times when the concentration of phosphoric acid is optimized with 7.4 at% in the SnO2 precursor. Furthermore, the stability of the perovskite layer deposited on the phosphate-passivated SnO2 (P-SnO2) ETL is gradually improved with the increase of the concentration. Due to the higher electron collection efficiency, the P-SnO2 ETLs can dramatically promote the power conversion efficiency (PCE) of the PSCs. As a result, the champion PSC has a PCE of 21.02%. Therefore, it has been proved that this simple method is efficiently to improve the quality of ETL for high performance PSCs.
关键词： electron transport layer,phosphate passivation,tin oxide,perovskite solar cell,electron collection efficiency
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE International Conference on Electro/Information Technology (EIT) - Rochester, MI, USA (2018.5.3-2018.5.5)] 2018 IEEE International Conference on Electro/Information Technology (EIT) - Electrochemical Phosphate Sensors Using Silver Nanowires Treated Screen Printed Electrodes
摘要： Essential biomolecules of the human body and plant growth depend upon the proper amount of phosphate ions. Phosphorus has critical values in both agricultural and biomedical applications. There is a need for inexpensive, portable, repeatable, highly sensitive and field deployable sensors with wide detection range to monitor the health of water system and to develop an electrochemical phosphate sensor using novel ammonium molybdate (AMT/AgNWs) modified screen printed electrode (SPE) for phosphate detection to achieve simplicity, high sensitivity, wide detection range, and high repeatability and portability. The cyclic voltammetry measurements exhibited the sensitivities of AMT modified SPE without and with AgNWs are 0.1 μA/μM and 0.71 μA/μM, respectively. The use of highly conductive AgNWs significantly increased the sensitivities of the AMT/SPE. Besides, AgNWs and AMT modified SPE (AMT/AgNWs/SPE) showed a very wide detection range of 5 μM -1 mM. Moreover, the proposed sensor demonstrated a good repeatability and recovery. Our work suggests that AMT/AgNWs/SPE is promising for simple, low-cost, and portable phosphate ion detection.
关键词： phosphate detection,ammonium molybdate,screen printed electrodes,electrochemical phosphate sensors,silver nanowires
更新于2025-09-10 09:29:36
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Raman spectra in LiH <sub/>2</sub> PO <sub/>4</sub> and KLi(H <sub/>2</sub> PO <sub/>4</sub> ) <sub/>2</sub> : Mode assignment
摘要： We report and analyze Raman spectra recorded on crystals of LiH2PO4 (LDP) and KLi(H2PO4)2 (KLDP). We provide a new and complete assignment of Raman lines in both crystals from their behavior as function of temperature. Among internal vibrations, we discern the modes within PO4 tetrahedra, the modes related to Li―O bonds, and those due to the O―H vibrations. In the wavenumber range between 300 and 600 cm?1, the lines associated with O―P―O or Li―O show different temperature dependencies. The bands of PO4 are red‐shifted with increasing temperature according to thermal dilatation, whereas the positions related to Li―O are temperature independent.
关键词： vibrational modes,phosphate compounds,crystal,thermal behavior,mode assignment
更新于2025-09-10 09:29:36
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A novel photocatalytic membrane decorated with PDA/RGO/Ag3PO4 for catalytic dye decomposition
摘要： In this study, a reduced graphene oxide/silver phosphate (RGO/Ag3PO4) was obtained via polydopamine (PDA) modification, and the PDA/RGO/Ag3PO4 composite was coated on the pure polyvinylidene fluoride (PVDF) membrane, which named PDA/RGO/Ag3PO4/PVDF memebrane. The PDA/RGO/Ag3PO4 was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Futhermore, the SEM, Energy dispersive spectrometer (EDS) spectrograms and Atomic force microscopy (AFM) were used to characterize the morphology structure, elemental mapping and roughness of PDA/RGO/Ag3PO4/PVDF memebrane. The results showed that the composite membrane has a good effect on the degradation of dyes, and the rejection rate of MB reached 99% with an increasing of the composite material ratio. The hydrophilicity of the membrane surface increased by measuring the contact angle, with decrease to 59.2°compared with 88.2°of pure PVDF membrane. In addition, under the visible light irrradiation, the coated membrane still keeps stable flux and high separation efficiency after 5 cycles. Hence, this study provides an attractive PVDF modified membrane.
关键词： graphene oxide,polydopamine,silver phosphate,dye rejection,coating membrane
更新于2025-09-10 09:29:36
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Yb3+/Tb3+/Ho3+: phosphate nanophase embedded glass ceramics: enhanced upconversion emission and temperature sensing behavior
摘要： Yb3+/Tb3+/Ho3+ tri-doped transparent phosphate glass–ceramics (GCs) were successfully synthetized by a conventional melt-quenching technique with subsequent glass crystallization. The formation of phosphate nanocrystals (NCs) with leucite structure was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected-area electron diffraction (SAED). The variation of the decay curves confirms the accumulation of active centers into the NCs lattice. Hence, the UC emission intensity of Yb3+/Tb3+/Ho3+ doped GC610 sample is greatly enhanced relative to that in precursor glass (PG). And the UC energy transfers processes were systematically analysis. The result shows that the energy transfer of Ho3+→Tb3+ exists while Yb3+ as a sensitizer ion. Furthermore, the temperature-dependent UC luminescence and temperature sensing behaviors of the prepared materials based on the thermally coupled levels of Tb3+: 5D4 and Ho3+: 5F5 in the temperature range of 298–648 K were systematically investigated, to explore its possible application as optical thermometric medium, by utilizing the fluorescence intensity ratio (FIR) technique. The relative sensitivity (Sr) of 7.5 × 10?3 K?1 and absolute sensitivity (Sa) of 22 × 10?3 K?1 are achieved in the Yb3+/Tb3+/Ho3+ tri-doped GC. This GC materials is a very promising candidate for optical temperature sensors.
关键词： Yb3+/Tb3+/Ho3+ tri-doped,phosphate glass–ceramics,upconversion emission,temperature sensing,optical thermometry
更新于2025-09-10 09:29:36
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The influence of niobium on the structure of Nb2O5–ZnO–P2O5 glasses
摘要： Bulk glasses of the compositional series (A) xNb2O5–(50-x)ZnO–50P2O5 and (B) xNb2O5–50ZnO-(50-x)P2O5 were prepared to investigate possible substitution of cation (Zn2+), series A, and anion (PO3?), series B, with niobium and the effect of this substitution on the structure, density, molar volume, glass transition temperature and coefficient of thermal expansion. The structure was studied by Raman and 31P MAS NMR spectroscopies. The chemical model, based on the idea of chemical compounds as components with the lowest Gibbs energy and therefore the most stable, and on the results of 31P MAS NMR spectroscopy, was proposed for series B. It was found that niobium acts in glasses of series B only as a cation NbO3+, unlike the original idea of forming an anion of NbO?, that is, similarly to series A, where it replaces the cation. This leads to a change in the metaphosphate network of series B to the network that is similar to series A glass. The validity of this idea was verified by experimentally obtained compositional dependencies of molar volume, glass transition temperature and thermal expansion coefficient. Changes observed in thermal measurements indicate the evolution of a more rigid structure and more intensive cross-linking of the phosphate chains with increasing content of niobium.
关键词： Phosphate glasses,Chemical model,Structure,Niobium,Thermal properties
更新于2025-09-10 09:29:36
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New way to produce large-scale sheets of 2D piezoelectric material
摘要： Researchers from RMIT University in Melbourne have developed a process for “printing” large-scale 2D piezoelectric materials, the first time that such surface deposition has been achieved. Their simple and inexpensive approach enhances the range of materials available to industry at this scale and quality, and could lead to a new generation of piezo-sensors and energy harvesting based on piezoelectric components that are directly integrated onto silicon chips.
关键词： printing,gallium phosphate,large-scale sheets,2D piezoelectric material,RMIT University
更新于2025-09-10 09:29:36
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Absorption and luminescence studies of Sm3+ ions activated in distinct phosphate glasses for reddish orange light applications
摘要： In the present work, we report the optical properties of Sm3+ ions doped glasses having chemical compositions (70-x) NH4H2PO4+15Na2O+15M2O + xSm2O3 (where x = 0.5 mol% and M = Li, Mg, Ca, Sr, Ba). Structural details are obtained from XRD, SEM, FTIR, Raman and solid-state 31P NMR spectra. Absorption (UV-NIR), emission and lifetime measurements have been performed and discussed using Judd-Ofelt theory. Various radiative parameters are calculated and discussed. Visible emissions from 4G5/2 excited state have been characterized and the experimental lifetimes of these levels have been compared with those obtained theoretically by using J-O approach. Quantum e?ciencies are reported. The CIE chromaticity co-ordinates of the present glass matrices con?rmed reddish-orange light emission. Hence the prepared samples can be treated as candidates for reddish orange light applications.
关键词： Photoluminescence,Phosphate glass,Absorption,FTIR,Emission cross-section,Solid state 31P NMR
更新于2025-09-10 09:29:36
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Evaluation of the shielding parameters of alkaline earth based phosphate glasses using MCNPX code
摘要： Glass systems of composition 16XO–3Al2O3–6CuO–20Na2O–55P2O5 (where X=Sr, Ca, Mg and Ba mol%) have been investigated to check its potential utilize as gamma ray shielding material. Different shielding quantities namely mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), half value layer (HVL) and mean free path (MFP) have been evaluated using MCNPX code and XCOM program at different photon energies between 0.015-10 MeV. The obtained data revealed good agreement between the μ/ρ values derived from XCOM and MCNPX code (version 2.6.0). It is found that the mass attenuation coefficients of BaO-doped phosphate glass are higher than those of the other alkaline earth elements–doped glasses, whereas MgO possess the lowest values. This indicates that the BaO-doped phosphate glass is the superior gamma radiation attenuator among the studied glass samples. The gamma shielding performance of the glasses under study has been compared to some commercial glasses and different concrete samples in terms of MFP.
关键词： MCNPX,effective atomic number,attenuation coefficients,radiation,Phosphate glass,XCom
更新于2025-09-10 09:29:36