Quantum theory of wave mixing on a two-level system

We apply the scattering matrix formalism to wave mixing on a quantum two-level system. We carry out the fermionization of the two-level system degrees of freedom using the Popov-Fedotov semions, calculate n-particle Green's function, and apply the Lehmann-Symanzik-Zimmermannn reduction procedure. Using the developed approach, we provide a consistent quantum explanation of the appearance of coherent side peaks observed in an experiment on the scattering of bichromatic radiation on a two-level artificial atom \cite{dmitriev2019probing}. We show that the spectrum observed in the experiment is the result of bosonic stimulated scattering of photons from one mode of the bichromatic drive to another and vice versa

Generation of a localised microwave magnetic field by coherent phonons in a ferromagnetic grating

A high-amplitude microwave magnetic field localized at the nanoscale is a desirable tool for various applications within the rapidly developing field of nanomagnetism. Here, we drive magnetization precession by coherent phonons in a metal ferromagnetic nanograting and generate ac-magnetic induction with extremely high amplitude (up to 10 mT) and nanometer scale localization in the grating grooves. We trigger the magnetization by a laser pulse which excites localized surface acoustic waves. The developed technique has prospective uses in several areas of research and technology, including spatially resolved access to spin states for quantum technologies

РЕСПИРАТОРНЫЕ НАРУШЕНИЯ В ОСТРОМ ПЕРИОДЕ ОСЛОЖНЕННОЙ ТРАВМЫ ШЕЙНОГО ОТДЕЛА ПОЗВОНОЧНИКА

Objective. Evaluating the results of respiratory therapy in patients with complicated traumatic injury of the cervical spine.Materials and methods. A retrospective comparative analysis of the clinical course was carried out in 52 patients with complicated traumatic injury of the cervical spine: group A: complete spinal cord injury (ASIA A), 37 patients and group B: incomplete injury (ASIA B), 15 patients. The severity of patients' status on integral scales, parameters of the respiratory pattern and thoracopulmonary compliance, gas composition, and acidbase status of the blood were assessed. Data on patients who required prolonged mechanical ventilation, duration of mechanical ventilation, incidence of nosocomial pneumonia, duration of stay in the ICU, time of hospital treatment, and mortality were included in the analysis. Results. The average APACHE II and SOFA scores were higher in group A patients. The development of the acute respiratory failure required longterm mechanical ventilation (more than 48 hours) in 91.4% of group A patients and in 53.3% of group B patients. Ventilatorassociated pneumonia complicated the disease in 81.3% of group A patients and 62.5% of group B patients and was accompanied by sepsis in 25% and 12.5% of cases, respectively. Statistically significant deterioration of biomechanical properties and gas exchange function of the lungs was observed in patients complicated with septic pneumonia.Conclusion. Patients with complicated ASIA A and ASIA B cervical spine injuries demonstrate the presence of respiratory failure of neurogenic origin. In addition, the infectious bronchopulmonary complications aggravated respiratory failure in patients with ASIA A injury in 70.3% versus 33.3% in patients with ASIA B. Developmentof pulmonogenic sepsis led to deterioration of the biomechanical and gas exchange functions of the lungs and increased the likelihood of unfavorable outcome of the disease in 77.8% of cases. The high incidence of respiratory disorders in patients with complicated cervical spine injury requires timely decision on ventilatory support, especially in patients with complete spinal cord injury.Цель исследования: определить частоту развития и характер респираторных нарушений у больных с осложненной травмой шейного отдела позвоночника в зависимости от исходного неврологического дефицита.Материалы и методы. Проведен ретроспективный сравнительный анализ течения заболевания у 52 пациентов с осложненной травмой шейного отдела позвоночника: группа A — полное повреждение спинного мозга (ASIA А) — 37 больных; группа В — неполное повреждение (ASIA В) — 15 больных. Оценивали тяжесть состояния пациентов по интегральным шкалам, показатели респираторного паттерна и торакопульмональной податливости, газовый состав и кислотноосновное состояние крови. Регистрировали количество больных, нуждавшихся в пролонгированной ИВЛ, длительность ИВЛ, частоту развития нозокомиальной пневмонии, длительность пребывания в ОРИТ, сроки стационарного лечения, летальность.Результаты. Средний балл по шкалам APACHE II и SOFA у больных в группе А имел более высокий уровень. Развитие острой дыхательной недостаточности требовало проведения длительной ИВЛ (более 48 ч) в группе А у 91,4% больных, а в группе В у 53,3% больных. Вентиляторассоциированная пневмония осложнила течение заболевания у 81,3% больных группы А и у 62,5% группы В с развитием сепсиса в 25% и в 12,5% случаях соответственно. Статистически значимое ухудшение биомеханических свойств и газообменной функции легких выявлено у больных, осложненных септической пневмонией.Заключение. Осложненная травма шейного отдела позвоночника типа ASIA A и ASIA B определяет на личие дыхательной недостаточности нейрогенного генеза. Присоединение инфекционных бронхолегочных осложнений усугубляет течение дыхательной недостаточности у пациентов с ASIA A в 70,3%, с ASIA В в 33,3% случаев. Развитие пульмоногенного сепсиса приводит к ухудшению биомеханических и газообменной функций легких и увеличивает вероятность неблагоприятного исхода заболевания в 77,8% случаев. Высокая частота респираторных нарушений у пациентов с осложненной травмой шейного отдела позвоночника требует своевременного принятия решения о необходимости респираторной поддержки, особенно у пациентов с полным повреждением спинного мозга

Experimental investigation of the process of hydrate-formation by the method of explosive boiling of liquefied freon 134a in the water volume during decompression

The experiments on obtaining gas hydrate of refrigerant 134a were carried out by the method, based on explosive boiling-up of a layer of liquefied gas in a bulk of water at decompression. It is shown that this method combines several factors, leading to intensification of hydrate formation process, resulting in the fast gas hydrate growth. The effect of the decompression rate on the volume of produced hydrate was studied experimentally

Influence of the water level in the work area on the hydrate formation process

This article describes a fundamentally new method for obtaining gas hydrates, based on self-organization in a closed working section of the cyclic boiling-condensation process of the gas-hydrate generator. A special feature of this method is the high rate of hydrate formation at low energy costs and, as a consequence, the expected efficiency of new technologies built on its basis over analogues. A series of experiments was performed, which shows the effect of the water level on the work site on the hydrate formation process

Experimental Investigation of Gas Hydrate Production at Injection of Liquid Nitrogen into Water with Bubbles of Freon 134A

The hydrodynamic processes during the injection of the cryogenic liquid into the volume of water with bubbles of gas freon 134a are studding experimentally. A processes during the explosive boiling of liquid nitrogen in the volume of water are registered. Video recording of identified gas hydrate flakes formed during this process is carried out by high speed camera. These results may be useful for the study of the new method of producing gas hydrates, based on the shock-wave method

Experimental Investigation of Gas Hydrate Production at Injection of Liquid Nitrogen into Water with Bubbles of Freon 134A

The hydrodynamic processes during the injection of the cryogenic liquid into the volume of water with bubbles of gas freon 134a are studding experimentally. A processes during the explosive boiling of liquid nitrogen in the volume of water are registered. Video recording of identified gas hydrate flakes formed during this process is carried out by high speed camera. These results may be useful for the study of the new method of producing gas hydrates, based on the shock-wave method