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Tunable thermo-piezo-plasmonic effect on core/shell nanoparticles under laser irradiation and external electric field
摘要： This work is focused on the characterization of the opto-heating generation in thermo-piezo-plasmonic solutions of gold-PbZrTiO3 (PZT) core/shell nanoparticles. Core/shell nanoparticles have been prepared by the laser ablation in liquid method. Linear and nonlinear optical properties of proposed nanoparticles were studied by optical spectroscopy and the Z-scan technique under external voltage to investigate the piezo-photonic effect. Furthermore, the linear optical properties of these nanostructures were calculated vie dipole approximation method with different core size and different shell thickness of samples immersed in water and poly-vinyl-pyrrolidone. In addition, thermo-plasmonic effects of samples are investigated theoretically and experimentally by the finite element method of COMSOL multiphysics V5.4 and infrared camera under laser irradiation and external electric field. The results revealed a clear tunable and adjustable linear and nonlinear behavior and thermo-piezo-plasmonic properties under external effects. The temperature elevation is ranging of ?T = 3.7–14.1 °C under different external effects. Accordingly, these results encourage to uses proposed samples for the cancer treatment and the different biomedical applications.
关键词： Nonlinear refractive index,External electric field,Core/shell NPs,Laser irradiation,Thermoplasmonic,Piezoelectric,Z-scan technique,Schottky barrier
更新于2025-09-23 15:21:01
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Handbook of Exoplanets || Microlensing Surveys for ExoplanetResearch (MOA)
摘要： The first 22 years of a search for exoplanets by gravitational microlensing that is being conducted by the Japan/NZ collaboration known as MOA are described. A range of techniques that was developed in association with other international collaborations is outlined, and these are typified by a chronological sequence of examples from the published literature. The detection of exoplanets in gravitational microlensing events of high and moderately high magnification is emphasized. Physical descriptions of these processes are given. Evidence for free-floating planets is also presented, and recent results on the mass-radius distribution of planets and on the planetary mass-function are given. Current plans for the near-term future of the international microlensing community are described, and also for the more distant future. The latter includes a survey of exoplanets that will be conducted by the WFIRST space telescope in the coming decade. Brief remarks are also made on early and current searches for dark matter by MOA.
关键词： dark matter,MOA collaboration,mass-radius distribution,exoplanets,planetary mass-function,WFIRST space telescope,high magnification technique,free-floating planets,gravitational microlensing
更新于2025-09-23 15:21:01
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Feasibility of Particle Image Velocimetry for Low-Speed Unconventional Vapor Flows
摘要： This work assesses the feasibility of the planar PIV technique to study the characteristics of a siloxane vapor D4. Titanium dioxide (TiO2) seeding particles were used to track the motion around a rotating disk in a low speed ?ow. Vector ?elds of natural convection (NC) and a superposition of NC and rotating ?ow were selected as exemplary cases. The particles were capable of tracing the ?ow since the calculated Stokes number St is 6.5 × 10?5. The quality of the experimental data is assessed by means of particle seeding density and particle image Signal to Noise ratio (S/N). The ?nal results are deemed acceptable for an accurate assessment of the ?ow ?eld. Rejected outliers are below 2.3% and the relative uncertainties corresponding to the average velocity ?elds are below 1 %.
关键词： PIV,siloxanes,low speed rotating organic vapor ?ow,seeding technique
更新于2025-09-23 15:21:01
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High-Throughput Fingerprinting of Rhizobial Free Fatty Acids by Chemical Thin-Film Deposition and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry
摘要： Fatty acids (FAs) represent an important class of metabolites, impacting on membrane building blocks and signaling compounds in cellular regulatory networks. In nature, prokaryotes are characterized with the most impressing FA structural diversity and the highest relative content of free fatty acids (FFAs). In this context, nitrogen-fixing bacteria (order Rhizobiales), the symbionts of legumes, are particularly interesting. Indeed, the FA profiles influence the structure of rhizobial nodulation factors, required for successful infection of plant root. Although FA patterns can be assessed by gas chromatography—(GC-) and liquid chromatography—mass spectrometry (LC-MS), sample preparation for these methods is time-consuming and quantification suffers from compromised sensitivity, low stability of derivatives and artifacts. In contrast, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) represents an excellent platform for high-efficient metabolite fingerprinting, also applicable to FFAs. Therefore, here we propose a simple and straightforward protocol for high-throughput relative quantification of FFAs in rhizobia by combination of Langmuir technology and MALDI-TOF-MS featuring a high sensitivity, accuracy and precision of quantification. We describe a step-by-step procedure comprising rhizobia culturing, pre-cleaning, extraction, sample preparation, mass spectrometric analysis, data processing and post-processing. As a case study, a comparison of the FFA metabolomes of two rhizobia species—Rhizobium leguminosarum and Sinorhizobium meliloti, demonstrates the analytical potential of the protocol.
关键词： bacteria,metabolic fingerprinting,matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS),barium monocarboxylates,free fatty acids (FFAs),chemical deposition technique,Langmuir film technology,rhizobia
更新于2025-09-23 15:21:01
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Characterization of Lattice Parameters Gradient of Cu(In1-xGax)Se2 Absorbing Layer in Thin-Film Solar Cell by Glancing Incidence X-Ray Diffraction Technique
摘要： In or Ga gradients in the Cu(In1-xGax)Se2 (CIGS) absorbing layer lead to change the lattice parameters of the absorbing layer, giving rise to the bandgap grading in the absorbing layer which is directly associated with the degree of absorbing ability of the CIGS solar cell. We tried to characterize the depth profile of the lattice parameters of the CIGS absorbing layer using a glancing incidence X-ray diffraction (GIXRD) technique, and then allows to determine the In or Ga gradients in the CIGS absorbing layer, and to investigate the bandgap grading of the CIGS absorbing layer. When the glancing incident angle increased from 0.50 to 5.00°, the a and c lattice parameters of the CIGS absorbing layer gradually decreased from 5.7776(3) to 5.6905(2) ?, and 11.3917(3) to 11.2114(2) ?, respectively. The depth profile of the lattice parameters as a function of the incident angle was consistent with vertical variation in the composition of In or Ga with depth in the absorbing layer. The variation of the lattice parameters was due to the difference between the ionic radius of In and Ga co-occupying at the same crystallographic site. According to the results of the depth profile of the refined parameters using GIXRD data, the bandgap of the CIGS absorber layer was graded over a range of 1.222 to 1.532 eV. This approach nondestructively guess the bandgap depth profile through the refinement of the lattice parameters using GIXRD data on the assumption that the changes of the lattice parameters or unit-cell volume follow a good approximation to Vegard’s law.
关键词： Vegard’s law,Cu(In1-xGax)Se2 absorbing layer,Depth profile,Bandgap grading,Glancing incidence X-ray diffraction technique
更新于2025-09-23 15:21:01
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Preparation of NiO/TiO2 Composite Films for Enhanced Dye Sensitized Solar Cell Efficiency
摘要： Spray pyrolysis technique has been applied for preparing many kinds of thin films because this technique offers a lot of advantages, such as inexpensive cost, uncomplicated process and large scale production. Therefore, the spray pyrolysis technique is used for making pure TiO2 and NiO/TiO2 composite films in this report. A NiO/TiO2 composite film is getting attention to be used as a compact layer in dye sensitized solar cell (DSSC) because NiO can be used as a hole collector and a barrier for energy recombination properties. Moreover, the NiO/TiO2 composite film exhibits superhydrophilic properties that can increase absorption efficiency for a dye solution. This study has an objective to improve the efficiency of DSSC by changing the ratio of NiO/TiO2 in the composite films. The pure TiO2 and NiO/TiO2 composite films were prepared at 200℃ by spray pyrolysis technique using a Ti(OCH(CH3)2)4 solution and a mixture of Ti(OCH(CH3)2)4 solution with Ni(NO3)2?6H2O powder, respectively. The effect of the ratio between Ni(NO3)2?6H2O powder and Ti(OCH(CH3)2)4 solution (0.5 atm%, 1 atm%, 2 atm%, and 4 atm% of Ni(NO3)2?6H2O) on the efficiency of DSSCs were studied. The surface morphology, crystal structure and optical properties of TiO2 and NiO/TiO2 composite films on FTO and glass substrates were characterized by using field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), and UV-VIS spectrophotometer, respectively. The FE – SEM images showed that the films were smooth surface and dense when prepared at 200 ℃. The XRD results of TiO2 and NiO/TiO2 composite films on the FTO substrates showed that the TiO2 crystals were anatase phase because the peak at 25.30 corresponds to (101) planes of anatase. The spectrophotometer results showed that the optical transmittance for all samples were about 80%. For the energy conversion efficiency characterization, it was found that the NiO/TiO2 composite films that were prepared from 0.5 atm% of Ni(NO3)2?6H2O solution had the better energy conversion efficiency than TiO2 films.
关键词： NiO/TiO2 composite film,Dye sensitized solar cell,Spray pyrolysis technique
更新于2025-09-23 15:21:01
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Synthesis, DFT studies, fabrication, and optical characterization of the [ZnCMC] <sup>TF</sup> polymer (organic/inorganic) as an optoelectronic device
摘要： A novel carboxymethyl cellulose zinc thin film [ZnCMC]TF was fabricated using the sol–gel technique. Different characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and the optical properties were used to study the properties of [ZnCMC]TF. The molecular structure, FTIR, and optical properties were optimized. The Raman spectrum of the [ZnCMC]TF complex shows several bands in the range of 72–556 cm?1 due to (nZn–O) stretching and (Zn–O) bending, which is an obvious distinction between the FTIR and Raman spectra of [ZnCMC]TF. The optimization was performed using density functional theory (DFT) by DMol3 and Cambridge Serial Total Energy Package (CASTEP) program. The chemical structure was confirmed by spectroscopic and structural properties for both CMC and [ZnCMC]TF; the XRD results showed the same crystal structure (Monoclinic 2). [ZnCMC]TF has a larger grain size than CMC and has a similar behavior in the optical gap energy. The optical constants increased with increasing photon energy, refractive index n, absorption index k, and optical conductivity. The SEM images provide very good evidence in favor of the reaction of zinc transition metal with CMC for the formation of the [ZnCMC]TF complex. The resulting [CMC] spherical thin film and the [ZnCMC]TF polymeric nanorods were examined by different techniques including TEM and EDX. The optical properties obtained from the simulated FTIR, XRD, and CASTEP are in good agreement with those obtained from the experimental studies on CMC and ZnCMC. Based on the optical findings, [ZnCMC]TF is a promising candidate in applications such as solar cells and optoelectronic devices.
关键词： TEM,DMol3,zinc thin film,carboxymethyl cellulose,UV-Vis,DFT,optoelectronic devices,XRD,EDX,CASTEP,sol–gel technique,SEM,FTIR,optical properties,Raman spectroscopy
更新于2025-09-23 15:21:01
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Growth and characterization of Cs2LiLaCl6:Ce single crystals
摘要： Cs2LiLaCl6:Ce (CLLC) is a promising scintillator material for dual gamma/neutron detection. The vertical Bridgman technique, with a LiCl-rich melt and high axial temperature gradient, was used to grow transparent CLLC crystals for the first time. The stoichiometric CLLC powder melted incongruently with a melting range of 343-442 oC. Additional LiCl suppressed the formation of Cs3LaCl6 second phase, which was identified in crystals grown from stoichiometric melts. CLLC was found to have a Stokes shift of about 1358 cm-1 and a photoluminescence decay time of 34.6 ns. Direct electron-hole capture by Ce3+ ions and core-valence luminescence were the main contributors to the X-ray induced luminescence spectrum. A 9×8 mm3 cylinder of the CLLC crystal with 0.5at% Ce had an energy resolution of 7.1% at 662 keV. The scintillation decay times of the CLLC crystal excited with 662 keV gammas were 79 ns and 1491 ns.
关键词： A1. Absorption spectra,B2. Scintillator materials,B1. Cs2LiLaCl6:Ce,B3. Neutron detection,A2. Bridgman technique
更新于2025-09-23 15:21:01
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Evaluation of marginal and internal fit of acrylic bridges using optical coherence tomography
摘要： Background: The potential of non-invasive optical coherence tomography (OCT) as a tool for assessment of fit of indirect reconstructions is not fully explored. Objectives: The objectives were to investigate the feasibility and validity of OCT, and to measure the internal and marginal fit of acrylic bridges fabricated using direct and indirect digitalization. Methods: The accuracy of the employed swept source OCT (wavelength: 1310nm) was assessed by comparing with an object with known dimensions. Validity was assessed by comparing OCT measurements on replica, mimicking the cement film thickness, with stereomicroscopic measurements. The reconstructions were placed on the abutments without cementation. The internal and marginal fit of acrylic bridges from direct and indirect digitalization techniques were then assessed by obtaining 5 OCT B-scans per abutment tooth at pre-defined positions located 250 μm apart. The marginal and internal cement gaps were measured using image-processing software (ImageJ). Mean and standard deviation were calculated for both groups and t-test assuming unequal variances was carried out. The level of significance was defined at 0.05. Results: A strong linear correlation (r = 0.865) between OCT and stereomicroscopy was found. T-test showed significantly (P < 0.01) better internal fit of bridges made from indirect digitalization, but no difference in marginal fit. Conclusion: OCT is a feasible and valid tool for investigating internal and marginal fit of acrylic dental reconstructions. Better internal fit was observed in bridges fabricated using the direct digitalization technique. No difference in marginal fit was found between the two fabrication methods.
关键词： Accuracy,Dental marginal fit,Replica technique,Optical coherence tomography,Dental internal fit,Acrylic Resins
更新于2025-09-23 15:21:01
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The Oscillatory Photoelectron Signal of <i>N</i> -Methylmorpholine as a Test Case for the Algebraic-Diagrammatic Construction Method of Second Order
摘要： Motivated by recent progress in the application of time-resolved photoelectron spectroscopy (TRPES) to molecular Rydberg states, we report herein a detailed assessment of the performance of the second-order algebraic diagrammatic construction (ADC(2)) method in the simulation of their TRPES spectra. As the test case, we employ the tertiary aliphatic amine N -methylmorpholine (NMM), which is notable for the fact that the signal of its 3s state exhibits long-lived oscillations along the electron binding energy axis. The relaxation process of photoexcited NMM is simulated via the Born-Oppenheimer molecular dynamics method, and the resulting TRPES spectrum is generated basing on ionization energies and approximate Dyson orbital norms calculated with the continuum orbital technique. On the whole, the simulated TRPES spectrum achieves satisfactory agreement with experiment, which suggests that the ADC(2) method provides a realistic description of the potential energy surfaces of the relevant excited and ionized states. In particular, the simulations reproduce the ?ne oscillatory structure of the signal of the 3s state, and provide evidence to the e?ect that it results from a coherent vibrational wavepacket evolving along the deformation modes of the six-membered ring. However, it is found that ADC(2) underestimates of electron binding energies by up to a few tenths of an electronvolt. The case of NMM demonstrates the usefulness of ADC(2) as a tool to aid the interpretation of the TRPES spectra of large organic molecules.
关键词： Dyson orbital,TRPES,ADC(2),time-resolved photoelectron spectroscopy,NMM,N-methylmorpholine,Rydberg states,Born-Oppenheimer molecular dynamics,continuum orbital technique,algebraic diagrammatic construction
更新于2025-09-23 15:21:01