Total pressure

About: Total pressure is a research topic. Over the lifetime, 5199 publications have been published within this topic receiving 66658 citations.

Method and apparatus for unifying the ventilation/perfusion and pressure/flow models

Abstract: A method and apparatus for unifying the pressure/flow and ventilation/perfusion ratios is disclosed. The apparatus includes monitors (38) which measure the medical condition of a patient. The monitors (38) are connected to an interface (40) and a relational database (42) and software which implements the method of the invention. The method includes determining the initial health condition of a patient to define a pulmonary pressure flow curve for each of a plurality of lung compartments of the patient, applying a stimulus of hypoxic pulmonary vasoconstriction to the pressure flow curve for each compartment to obtain a pressure flow curve for each compartment, and deriving a pulmonary artery pressure value corresponding to a ventilation/perfusion ratio that satisfies both the individual and total pressure flow requirements for the pulmonary pressure/flow curves.

A parametric study of the deposition of the TiN thin films by laser reactive ablation of titanium targets in nitrogen: the roles of the total gas pressure and the contaminations with oxides

Abstract: The multipulse excimer laser-reactive ablation of a titanium target in nitrogen has been found to result in a total pressure of the ambient gas in the range 7–70 μbar, in the deposition on to a silicon collector surface of high-purity f c c TiN thin films. These films were hard and adherent to substrate. The deposition rate was 0.03–0.05 nm per pulse for an incident laser fluence of ≥5 J cm−2. For a lower gas pressure of a few microbars the deposits were amorphized with an excess of titanium. For a nitrogen pressure larger than 100 μbar, the layers were contaminated with oxides. The oxides became more abundant with further increase in the gas pressure, and the deposited layer consisted of oxides only when the pressure reached several millibars.

Growth rate control and solid–gas modeling of TFA-YBa2Cu3O7 thin film processing

Abstract: The trifluoroacetate metal-organic decomposition route to YBa2Cu3O7 film growth was investigated in order to bring new insights in the growth mechanism and its dependence on processing conditions and critical current density. Precursor films were processed on LaAlO3 substrates at different total pressure, oxygen partial pressure, water vapor partial pressure, and volume gas flow rate keeping the growth temperature at 740??C. The influence of these various experimental parameters on the film growth rate, which was evaluated by in?situ electrical resistance measurements, was studied thoroughly. It was found that the growth rate is nearly independent of the oxygen pressure and proportional to the square root of the water pressure. Additionally, the growth rate increases with a decrease of the total pressure or an increase of the gas flow rate. An empirical multi-exponential model simulates the experimental data, however, a better understanding was achieved using a theoretical solid?gas reaction?diffusion model, including both the diffusion of the product HF gas from the surface and the chemical reaction kinetics at the YBCO/precursor interface. A complex cross-linked relationship between the film growth rate and the processing parameters has been properly verified from the experimental data. Finally we showed that the growth rate is an important parameter influencing the critical current densities of YBCO films because it controls the nucleation of non-c-axis oriented grains.