- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Aspects of the Formation of Tin Oxide under Annealing of Nanopowders Obtained by Pulsed Laser Ablation of Metallic Tin in Aqueous Media
摘要： Nanocolloids, obtained by pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns, 150 mJ) of metallic Sn in distilled water and also in solutions of hydrogen peroxide and nitric acid, were dried and subjected to heat treatment at different temperatures up to 800°С. It has been shown that addition of H2O2 or HNO3 has an effect not only on the size characteristics and structure of the initial nanoparticles, but also on the process of formation and the final characteristics of SnO2 under annealing. By the method of powder x-ray diffraction it was established that in the case of pulsed laser ablation in water and in a solution of nitric acid, the initial particles contain the phase SnO, but for annealed sample obtained by ablation in HNO3, an intermediate orthorhombic phase of SnO2 is formed. Additional studies using Raman spectroscopy and thermal analysis made it possible to determine the presence of tin hydroxide in the initial samples and formation of intermediate forms of its oxides, SnOx, upon annealing.
关键词： pulsed laser ablation,nanoparticles,tin oxide,Raman spectra,crystal structure,annealing
更新于2025-09-12 10:27:22
-
Preparation of silicon naphthalocyanine nanoparticles by laser ablation in liquid and their optical properties
摘要： Silicon naphthalocyanine nanoparticles were successfully prepared by laser ablation in liquid. Silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) powders in deionized water were irradiated with nanosecond-pulsed laser (Nd:YAG, SHG) to prepare nanoparticles. The prepared nanoparticles were investigated by scanning electron microscopy, dynamic light scattering and spectrophotometry. The shape was polygonal and partially spherical. The primary and secondary particle sizes were reduced with an increase in laser fluence. Absorbance was increased at low laser fluence and was constant at high laser fluence with the increase in laser fluence. The ratio of the two absorbance peaks was changed with the increase in laser fluence.
关键词： optical properties,laser ablation in liquid,nanoparticles,photoacoustic imaging,silicon naphthalocyanine
更新于2025-09-12 10:27:22
-
Pulsed laser ablated zeolite nanoparticles: A novel nano‐catalyst for the synthesis of 1,8‐dioxo‐octahydroxanthene and <i>N</i> ‐aryl‐1,8‐dioxodecahydroacridine with molecular docking validation
摘要： There is an increasing interest in the synthesis of metal nanoparticles (NPs) from bulk metals using pulsed laser ablation in liquids (PLAL), as it offers an easy and simple synthesis route. In this work, zeolite NPs (molecular sieve 4A) were successfully synthesized by the PLAL technique, and characterized by X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, and high‐resolution transmission electron microscopy. Data obtained confirm the formation of the crystalline phase of zeolite. The synthesized catalyst (zeolite molecular sieve 4A) was used as an efficient and facile promotor for the synthesis of xanthene and acridine derivatives. Molecular docking of the synthesized compounds was validated using quinone reductase 2 (NQO2) and acridine orange as the ligand, with the synthesized molecules showing good drug–ligand interaction on the active site of NQO2, compared with that of acridine orange.
关键词： zeolite,acridine,xanthene,laser ablation,nanoparticles,dimedone
更新于2025-09-12 10:27:22
-
UNRAVELLING QUASI-CONTINUOUS <sup>14</sup> C PROFILES BY LASER ABLATION AMS
摘要： Laser ablation (LA) accelerator mass spectrometry (AMS) is a novel method for rapid online radiocarbon (14C) analysis of carbonates. The quasi-continuous 14C profiles obtained with this technique demand a customized data evaluation protocol to relate the acquired 14C data to the analyzed sample. We take into account the mixing effects due to the minimal counting (integration) time of the AMS, the finite width of the laser beam and the gas washout of the ablation volume. Thereby we mathematically describe our LA setup with a system function that acts on the produced CO/CO2 (COX) from the sample resulting in a mixing of the 14C profiles obtained by AMS analysis. Furthermore, we analyze the long-term target memory effect in the gas ion source and establish a routine for correction. The correction routine is tested with a stalagmite comprising a growth stop that is analyzed at different scanning velocities indicating that only the slow scanning velocity can provide the necessary resolution to determine the width of the growth stop of 365 μm.
关键词： carbonates,laser ablation,online 14C analysis,gas ion source
更新于2025-09-12 10:27:22
-
Lesion Network Localization of Seizure Freedom following MR-guided? Laser Interstitial Thermal Ablation
摘要： treatment-resistant epilepsy is a common and debilitating neurological condition, for which neurosurgical cure is possible. Despite undergoing nearly identical ablation procedures however, individuals with treatment-resistant epilepsy frequently exhibit heterogeneous outcomes. We hypothesized that treatment response may be related to the brain regions to which MR-guided laser ablation volumes are functionally connected. to test this, we mapped the resting-state functional connectivity of surgical ablations that either resulted in seizure freedom (N =?11)?or?did?not?result in seizure freedom (N =?16)?in?over?1,000?normative?connectomes.?There?was?no?difference?seizure outcome with respect to the anatomical location of the ablations, and very little overlap between ablation?areas?was?identified?using?the?Dice?Index.?Ablations?that?did?not?result?in?seizure-freedom?were preferentially connected to a number of cortical and subcortical regions, as well as multiple canonical resting-state networks. in contrast, ablations that led to seizure-freedom were more functionally connected to prefrontal cortices. Here, we demonstrate that underlying normative neural circuitry may?in?part?explain?heterogenous?outcomes?following?ablation?procedures?in?different?brain?regions. These?findings?may?ultimately?inform?target?selection?for?ablative?epilepsy?surgery?based?on?normative intrinsic connectivity of the targeted volume.
关键词： resting-state functional connectivity,seizure freedom,treatment-resistant epilepsy,MR-guided laser ablation,prefrontal cortices
更新于2025-09-12 10:27:22
-
[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - THz Properties of Fe and Ti Oxides Nanoparticles Obtained by Pulsed Laser Ablation
摘要： We present Dielectric properties of Fe and Ti oxides nanoparticles (NPs) measured by THz-TDS. The NPs were obtained via ns pulsed laser ablation (PLA) of the metals in air and water and were annealed at different temperatures. In the paper, we exhibit the dependence of absorption spectra on NPs structure: from magnetite to hematite for Fe, and from anatase to rutile for Ti. The prospects for their use as materials for the THz photonics are discussed.
关键词： THz-TDS,Fe and Ti oxides nanoparticles,THz photonics,dielectric properties,pulsed laser ablation
更新于2025-09-12 10:27:22
-
High-performance oil-water separation polytetrafluoroethylene membranes prepared by picosecond laser direct ablation and drilling
摘要： The membranes with special surface wettability have attracted considerable attention, especially in the practical applications of oil-water separation. Here, we presented a simple and rapid method of picosecond (ps) laser direct ablation and then drilling to fabricate high-performance oil-water separation polytetrafluoroethylene (PTFE) membrane. It was found that the as-prepared rough PTFE membranes had ca. 0° contact angle (CA) of oil in air and above 150° CAs of water in air or oil, respectively, exhibiting superoleophilicity and under-oil superhydrophobicity. The micropore size of the membranes was less than ca. 180 μm, the corresponding separation efficiencies were over 99.0% for different oil-water mixtures due to the special and rough surface microstructures. Importantly, the separation efficiencies and fluxes of the as-prepared membranes showed no obvious change with suffering heavy erosion or 40 separation cycles, indicating that the membranes had excellent stability and applicability. Additionally, the effect of the special and rough surface on oil-water separation performance was investigated. This work provides a new pathway for the rapid fabrication of high-performance separation membranes.
关键词： Picosecond laser ablation,Superoleophilicity,Polytetrafluoroethylene,Superhydrophobicity,Oil-water separation
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Controllable Generation of Ultrashort Multi-Bound Solitons in a Mode-Locked Erbium-Doped Ring Laser with a Highly-Nonlinear Resonator
摘要： Mode-locked (ML) ultrashort pulse (USP) fiber lasers can be treated as an ideal platform to expand future applications due to a complex nonlinear dynamics with a presence of a high value of a group velocity dispersion and a third-order dispersion in the laser resonator. Up to now a series of novel ML regimes have been investigated e.g. self-similar pulses, noise-like pulses, multi-bound solitons, and a soliton rain generation. Multi-bound solitons (MBS) generation regime, also known as soliton molecules, is of considerable interest in various fields of applications. For example, the investigation of a MBS generation is very attractive for increasing the data transfer capacity in telecommunications due to coding alphabet extension. The coding concept of MBS suggests a data stream using more than two symbols (2?N symbols, where N is the number of generated solitons in a bound state) [1]. And also, recent research shows that using ultrafast bursts of pulses can improve the quality of laser ablation for medical applications [2]. Moreover, MBS generation can be also used in a coherent pulse staking amplification scheme increasing an amplification efficiency along with a formation of high-energy solitons at a high-repetition-rate [3]. Previously we have obtained a generation of stable low-noise ultrashort multi-bound solitons in a passive mode-locked all-fiber erbium-doped ring laser with a highly-nonlinear resonator [4]. Fig. 1 shows autocorrelation traces and spectrums of MBS generation obtained by pump power variation at a wavelength of 980 nm. The output spectrums are evidently showing high-contrast intensity fringes (up to ~20 dB) and autocorrelation traces having symmetrical form without additional intensity peaks that indicates a stable and strong coherent connection between ultrashort pulses and fixed coherent phase difference in the temporal domain between several identical pulses. It is known that the highest energy of a fundamental soliton in a laser resonator with duration τp is limited by the soliton area theorem Es ~ |β2|/(γ · τp), where γ is the net nonlinear coefficient and β2 is the total cavity dispersion [1]. Soliton energy quantization results in pulse splitting at operation powers higher than the fundamental limit. Here we experimentally demonstrate the formation multi-bound solitons with the controllable number of bound states 7 < N < 17 by pump power variation in the range from ~160 mW to ~377 mW obtained in a highly-nonlinear fiber ring cavity.
关键词： ultrashort pulse,laser ablation,fiber lasers,Mode-locked,coherent pulse staking amplification,soliton molecules,telecommunications,multi-bound solitons
更新于2025-09-12 10:27:22
-
High Aspect Ratio Microstructuring of Copper Surfaces by Means of Ultrashort Pulse Laser Ablation
摘要： Laser beam machining (LBM) is capable of almost force-free 2D and 3D machining of any kind of material without tool wear. This process is defined by many parameters, such as pulse energy, frequency, scanning velocity and number of scanning repetitions. Modern laser machines provide high energy at shorter pulse durations and have more precise positioning systems than machines of the past. These can easily fulfil today’s continuous changing product requirements. For an overall understanding, an extensive amount of experimentation is required to display the interaction laws and dependencies between process parameters, as well as the resulting shapes and quality of the machined surface. By using an ultrashort pulse (USP) laser, a wide range of customer oriented applications in micrometer scale can be addressed, which leads to precise ablation with minimal thermal damage. This paper provides knowledge on the machining of copper micro features with high aspect ratio and a 532 nm wavelength laser beam. Aspect ratios up to 17 and slot widths smaller than 20 μm were performed with a beam radius ω0 smaller than 5 μm and pulse duration smaller than 12 ps. For desired slot geometries, necessary process parameters were developed and their physical limits are shown and discussed. The limits of minimum structure size have been analysed by observing the remaining material between slots at decreasing distances. Material debris deposits on the non-machined surface, as well as chemical changes of copper, were analysed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Special attention was given to the taper angle, which arises due to the Gaussian distribution of energy in the laser beam.
关键词： cold laser ablation,micro machining,high aspect ratio
更新于2025-09-12 10:27:22
-
Post-processing of additively manufactured cutting edges by laser ablation
摘要： In the packaging industry, cutting dies are used to process paper based material. The dies are mainly manufactured via steel strip principle, which consists of many manual steps and is difficult to automate. Laser material processing represents a promising approach to simplify manufacturing. This study realized additively manufactured cutting edges post-processed by laser ablation to achieve a defined final profile shape. First verification shows that laser ablation appears to be attractive for finishing of additively manufactured cutting edges.
关键词： angle of incidence,additive manufacturing,hybrid production,laser ablation,cutting edge,post-processing
更新于2025-09-12 10:27:22