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Stable and compact nanosecond pulse seed source with diode laser driven by a high-speed circuit and a temperature control circuit
摘要： We demonstrated a nanosecond pulse seed source with a diode laser (DL) of 1550 nm A short pulse generator and a short pulse driver came to form a high-speed circuit that drove the seed source. A temperature control circuit was employed to control the stability of the laser pulses. The experimental results provided that continuously adjustable 5 kHz to 25 MHz repetition frequency and 3.5 ns to 51 ns pulse duration were acquired. The ?ne tuning of pulse duration of seed signals was realized by adjusting the current of the laser in its operating current range. Stability of the output power over two hours was 0.13% at repetition frequency of 25 MHz and pulse duration of 3.5 ns, respectively.
关键词： Short pulse generator,Temperature control,Short pulse driver,Pulse seed source,Nanosecond pulse
更新于2025-11-28 14:24:03
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One-step synthesis of hexylresorcinol calix[4]arene-capped ZnO–Ag nanocomposites for enhanced degradation of organic pollutants
摘要： In this study, hexylresorcinol calix[4]arene (HRCA) is introduced into the reaction system, and HRCA-capped ZnO–Ag nanocomposites are prepared via a simple one-step reflux method. HRCA is used not only as a reducing agent for deoxidizing Ag+ to Ag, but also as a protectant for wrapping around the microstructure of the formed ZnO–Ag. The prepared samples are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and water contact angle. The Ag nanoparticles and ZnO adhere to each other and HRCA molecules encapsulate on the surface of ZnO–Ag nanocomposites. HRCA-capped ZnO–Ag nanocomposites with different Ag contents are investigated for use in photodegradation of organic pollutants (rhodamine B (RhB) and levofloxacin hydrochloride). The sample with 10.20 mol% Ag, denoted as ZA3, exhibits the highest catalytic activity for photodegradation of RhB and levofloxacin hydrochloride. Moreover, ZA3 exhibits high stability during photodegradation of organic pollutants even after multiple reuses. The possible photocatalytic mechanism is discussed. We believe that ?O2– and h+ are the chief active species responsible for the photocatalytic activity of HRCA-capped ZnO–Ag nanocomposite system. HRCA-capped ZnO–Ag nanocomposite is expected to be an effective photocatalyst with potential application to sewage treatment under sunlight.
关键词： HRCA-capped ZnO–Ag,Photocatalysis,Resorcinol calix[4]arene,Ag seed
更新于2025-11-21 11:03:13
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Au@Cu Core-Shell Nanocubes with Controllable Sizes in the Range of 20-30 nm for Applications in Catalysis and Plasmonics
摘要： Predominantly covered by a single type of {100} facets, Cu nanocubes are attractive catalytic material toward reactions such as electrochemical reduction of CO2. Here we report a seed-mediated approach to the facile synthesis of Au@Cu core-shell nanocubes with hexadecylamine and Cl- serving as capping agents toward the {100} facets of Cu and glucose as a reducing agent. The large (12%) lattice mismatch between Cu and Au led to the localized epitaxial growth of Cu shells on the Au seeds and the formation of nanocubes with randomly distributed Au cores. Compared to the same synthesis in the absence of Au seeds, the reduction of Cu(II) ions was greatly accelerated in the presence of Au seeds because of the autocatalytic surface reduction. It was also found that the structure and morphology of the products were highly dependent on the concentration of Cu(II) precursor in the reaction solution. Nanoplates rather than nanocubes were obtained when the concentration of Cu(II) precursor was reduced down to a certain level. By varying the reaction time and/or the amount of Au seeds, the size of the Au@Cu nanocubes could be tuned in a range of 20–30 nm. The as-synthesized core-shell nanocubes exhibited a strong localized surface plasmon resonance peak at 581 nm and the resonance was dominated by absorption rather than scattering. It is expected that the Au@Cu nanocubes with uniform and controllable sizes will find use in a variety of applications such as plasmonics and catalysis.
关键词： lattice mismatch,Copper nanocubes,core-shell nanocrystals,plasmonics,seed-mediated growth
更新于2025-11-19 16:56:35
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Effect of NaNbO <sub/>3</sub> Crystals on the Electrical Properties of Na <sub/>0.47</sub> K <sub/>0.47</sub> Li <sub/>0.06</sub> NbO <sub/>3</sub> Ceramics Synthesised by Seed Induced Method
摘要： In this work, we investigated the influence of crystalline NaNbO3 on the electrical properties of Na0.47K0.47Li0.06NbO3 (NKLN) ceramics. Preparation by the conventional method for the upcoming phase of random elements did not control the properties. For this reason, we studied the electrical properties and phase formation that occurred with the addition of NaNbO3 crystals, used at the initial phase of the reaction, in order to modify the electrical properties of NKLN ceramics. We synthesized lead-free piezoelectric ceramics by the seed-induced method. We prepared the NaNbO3 crystals used as seeds by molten salt synthesis (MSS). We mixed the powder oxides of Na2CO3 and Nb2O5 with NaCl oxides-salt ratio 1:6. The seeds varied in content from 0 to 20 mol%. The calcination temperature of NKLN was from 800 to 900 °C for 10 h, using two-step sintering (TSS) techniques. Our investigation further reported on the microstructure and the electrical properties. The results showed high Curie temperature of about 480 °C, while the effect of the seed crystal improved the piezoelectric properties of the samples, compared with the conventional mixed-oxide.
关键词： Seed-Induced Method,NKLN,Lead-Free Ceramic,NaNbO3
更新于2025-11-14 17:28:48
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Enhanced Oxidation Stability of Transparent Copper Films Using a Hybrid Organic-Inorganic Nucleation Layer
摘要： We report a novel seed layer for the formation of slab-like transparent copper films on glass and plastic substrates, based on a mixed molecular monolayer and an ultra-thin (0.8 nm) aluminium layer both deposited from the vapour phase, which substantially outperforms the best nucleation layer for optically thin copper films reported to date. Using this hybrid layer, the metal percolation threshold is reduced to < 4 nm nominal thickness and the long-term stability of sub-10 nm films towards oxidation in air is comparable to that of silver films of the same thickness fabricated using the best reported seed layer for optically thin silver films to date. The underlying reason for the remarkable effectiveness of this hybrid nucleation is elucidated using a combination of photoelectron spectroscopy, small angle X-ray studies, atomic force microscopy and transmission electron microscopy.
关键词： ultrathin metal film,nucleation,transparent electrode,seed layer,passivation,copper
更新于2025-10-22 19:40:53
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Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate
摘要： In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide (AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.
关键词： conductivity,ZnO nanowire arrays,seed layer free,AZO substrate
更新于2025-09-23 15:23:52
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Size and dimension dependent surface-enhanced Raman scattering properties of well-defined Ag nanocubes
摘要： Understanding the role of the morphology and particle–particle interactions on the plasmonic properties is of significant importance for the development of nanomaterials with excellent optical properties. However, the preparation of precisely defined nanomaterials with sizes that span a large range and their controllable self-assembly still remain a great challenge. Here, a multistep seed-mediated method has been established for preparing uniform Ag nanocubes over a broad size range from nanoscale (50 nm) to microscale (1400 nm) and with different hierarchical nanostructures range from “zero-dimension” (“0D”) to “three-dimension” (“3D”). The influence of the size and the interactions between the Ag nanocubes on their surface-enhanced Raman scattering (SERS) properties have been systematically and quantitatively investigated. It is demonstrated through experiments and finite-difference time-domain (FDTD) calculations that the SERS activity is dependent on the matching of the nanocube size to the excitation wavelength. The optimal combinations are 80, 110 and 130 nm nanocubes with respect to 532, 638 and 785 nm excitation wavelength, respectively. Furthermore, the Raman enhancement of the Ag nanocube hierarchical nanostructures increases rapidly from “0D” to “3D”, due to the extra increase of the hot spots that is attributed to the out-of-plane plasmonic coupling realized in the “3D” hierarchical nanostructures. This work clearly illustrates the quantitative role of the size and dimension of Ag nanocubes on their SERS properties and provides fundamental information for the design of advanced nanomaterials with higher SERS sensitivity.
关键词： Silver nanocubes,Self-assembly,Surface-enhanced Raman scattering,Seed-mediated method
更新于2025-09-23 15:23:52
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Rapid, non-destructive determination of ginseng seed moisture content by near infrared spectroscopy technology
摘要： Ginseng seed moisture content (SMC) determination and monitoring are of great importance during seed storage and in trading. The traditional oven-drying method for SMC measurement is accurate but takes both time and labour. The objective of this study was to develop a rapid and non-destructive method for ginseng SMC determination using near infrared (NIR) spectroscopy. Eighteen freshly harvested seed lots stored for different periods (days) were used for NIR model development and 12 commercial seed lots were used for validation of the model. The model developed in the present work had an R2 of 0.9913, residual prediction deviation (RPD) of 11.3 and low root mean square errors assessed by cross-validation (RMSECV; 0.387%). For commercial seed lot measurement, the predicted values of SMC were nearly the same as measured ones, with the relative differences less than 2.96%. In conclusion, NIR spectroscopy suitable for rapid and nondestructive determination of ginseng SMC.
关键词： near infrared spectroscopy,seed moisture content,ginseng
更新于2025-09-23 15:23:52
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Morphology Control of Hydrothermally Grown ZnO Nanostructures by Additives and Seed Layers
摘要： We present a rational control over the morphology of hydrothermally grown ZnO nanostructures by introducing different additives, sequential seeding, and multilayer seeds. The aspect ratio of the ZnO nanorods could be tuned with different types of additives (surfactant, amine, metal salt, and polymer additives) at an appropriate concentration in solution for ZnO hydrothermal growth. Some of the metal salts induced change in both aspect ratio and coverage simultaneously. The degree of vertical alignment of the ZnO nanowires was influenced by the number of seed layers. Furthermore, hierarchical ZnO nanostructures could be fabricated for thermal annealing on a secondary seed layer. The various control parameters demonstrated in this study provide beneficial information that can be used to guide a new strategy for relevant future applications.
关键词： Seed,Additive,Morphology,Hydrothermal,Zinc Oxide
更新于2025-09-23 15:22:29
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Photodegradation of 2-Chlorophenol in TiO2/UV System: Phytotoxicity Assessment of Treated Solutions Against Seedling Growth of Turnip and Tomato
摘要： The photodegradation and detoxification of 2-chlorophenol (2-CP) in TiO2 suspensions were studied using monochromatic UV-lamp. The effect of pH on the photodegradation of 2-CP was investigated. Removal of 98% of initial 2-CP was achieved within 210 under optimum concentration of 2-CP (60 mg/L) and TiO2 (80 mg/L). The apparent first-order rate constant kapp of 2-CP is estimated to be 0.0043 min–1 at pH 4, while a 3-fold increase in kapp was observed at pH 9. Phytotoxicity effects of treated 2-CP on seed germination, root elongation and plant growth of tomato (Lycopersicon esculentum) and turnip (Brassica rapa) seeds were also carried out with the aim of water reuse and environment protection. No statistically differences have been also found to exist for seed germination of tomato and turnip between deionized water (control) and phototreated 2-CP solution, indicating a significant removal of the overall toxicity. In the 10th day of germination, the average root elongation increases at 210 min of photocatalytic degradation yielding 7.1 ± 0.9 and 5.6 ± 0.66 cm for turnip and tomato seeds, respectively. Turnip plants irrigated with the phototreated 2-CP solution grow in a similar manner as the plant irrigated with the tap water. The phototreated 2-CP can be used in the irrigation of agriculture garden but only after further treatment.
关键词： root elongation,seed germination,TiO2,2-chlorophenol
更新于2025-09-23 15:22:29