The SERS (surface enhanced Raman spectroscopy) substrates based on nanocomposite porous films with gold nanoparticles (Au NPs) arrays were formed using the method of the pulsed laser deposition from the back low-energy flux of erosion torch particles on the glass substrate fixed at the target plain. The dependencies of porosity, and morphology of the surface of the film regions located near and far from the torch axis on the laser ablation regime, laser pulses energy density, their number, and argon pressure in the vacuum chamber, were ascertained. The Au NPs arrays with the controllable extinction spectra caused by the local surface plasmon resonance were prepared. The possibility of the formation of SERS substrates for the detection of the Rhodamine 6G molecules with the concentration 10−10 Mol/L with the enhancement factor 4·107was shown.
Purpose. To obtain experimentally that the duration of the high-voltage pulse front is less than 1.5 nanoseconds on the load of a pulse voltage generator of less than 50 ohms in the form of more than two working chambers with a water-containing product. That increases the efficiency of disinfection of treated products. Methodology. To obtain high-voltage pulses in working chambers -the generator load -the pulse generation method was used according to the Arkadyev-Marx scheme. The pulses on the load were measured with a low-ohm resistive voltage divider, transmitted over a broadband coaxial cable, and recorded using a C7-19 oscilloscope with a 5 GHz bandwidth. The working chambers were filled with water and consisted of an annular body made of PTFE 4 and metal electrodes forming the bottom and the chamber cover having flat linings of food stainless steel for contact with the food product inside the chamber. Results. The high-voltage pulses on the generator load of about 50 Ohm or less have a trapezoidal shape with a rounded apex and a base duration of no more than 80 ns. The experimentally obtained pulse amplitudes on the generator load are up to 18 kV. As the load resistance decreases, the amplitude of the pulses decreases, and the duration of the front and pulse duration in general are shortened because of the accelerated discharge of cascade capacitive storages. Originality. For the first time we have obtained experimentally on the load of the generator in the form of three parallel working chambers with water, the active resistance of each of which is less than 50 Ohm, the pulse front duration t f ≈1 ns. In addition, we have obtained experimentally a stable 9-10 channel triggering mode of the trigatron type spark gap in a five-cascade pulse voltage generator with a step-by-step peaking (exacerbation) of the pulse front in its cascades (GPVCP). Practical value. We have obtained experimentally the nanosecond pulse front duration on the GPVCP load and that opens the prospect of industrial application of such generators for microbiologically disinfecting treatment (inactivation of microorganisms in food) watercontaining food products. References 6, figures 8. Key words: generator of pulsed voltages, peaking of the pulse front in cascades of generator, working chamber, spark gap or switch, inactivation of microorganisms in food products.Цель. Экспериментально получить на нагрузке генератора импульсных напряжений величиной менее 50 Ом в виде более двух рабочих камер с водосодержащим продуктом длительность фронта импульсов высокого напряжения менее 1,5 наносекунд, что повышает эффективность обеззараживания обрабатываемых продуктов. Методика. Для получения высоковольтных импульсов на рабочих камерах -нагрузке генератора применена методика генерирования импульсов по схеме Аркадьева -Маркса. Импульсы на нагрузке измерялись при помощи низкоомного резистивного делителя напряжения, передавались по широкополосному коаксиальному кабелю и регистрировались при помощи осциллографа С7-19 с полосой пропускания 5 ГГц. Рабочие кам...
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