182 research outputs found

    The invention of fiberoptic videoguide intubation

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    Introduction: Airway management is one of the most important medical priorities. Despite its benefits, intubation can be sometimes associated with many complications and hardships. Hard intubation can have dangerous consequences, including hypoxia, increased intracranial pressure, cardiac collapse-vascular, traumatic anatomical areas and inflammation. The purpose of this device building is to reduce such complications.Material and Method: This tool can be used to examine film and photographs of pharyngeal organs, epiglottis, vocal cords and proximal esophagus episodes and the upper esophagus, trachea and bronchi.Discussion: Conventional laryngoscopes and video laryngoscopes are the instruments used in intubation, each of which has its own functional limitations. Of these limitations, it is difficult to intubate that due to the lack of proper view of the anatomical routes, the processor may fail. Fiberopathic videography is a tool that can be used in the chest tube intubation, especially in difficult conditions, operating rooms, and other pre-hospital settings.Results: Fiberopathic videography, a simple and very inexpensive tool that can visualize anatomical paths, shape simplicity directly facilitates the process of commuting and reduces potential complications.Keywords: Fiberoptic, Videoguide, Intubation, Thrace

    Discrete breathers assist energy transfer to ac driven nonlinear chains

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    One-dimensional chain of pointwise particles harmonically coupled with nearest neighbors and placed in six-order polynomial on-site potentials is considered. Power of the energy source in the form of single ac driven particles is calculated numerically for different amplitudes AA and frequencies ω\omega within the linear phonon band. The results for the on-site potentials with hard and soft nonlinearity types are compared. For the hard-type nonlinearity, it is shown that when the driving frequency is close to (far from) the {\em upper} edge of the phonon band, the power of the energy source normalized to A2A^2 increases (decreases) with increasing AA. In contrast, for the soft-type nonlinearity, the normalized power of the energy source increases (decreases) with increasing AA when the driving frequency is close to (far from) the {\em lower} edge of the phonon band. Our further demonstrations indicate that, in the case of hard (soft) anharmonicity, the chain can support movable discrete breathers (DBs) with frequencies above (below) the phonon band. It is the energy source quasi-periodically emitting moving DBs in the regime with driving frequency close to the DBs frequency, that induces the increase of the power. Therefore, our results here support the mechanism that the moving DBs can assist energy transfer from the ac driven particle to the chain.Comment: 11 pages, 13 figure

    Soliton-potential interaction in the nonlinear Klein-Gordon model

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    The interaction of solitons with external potentials in nonlinear Klein-Gordon field theory is investigated using an improved model. The presented model has been constructed with a better approximation for adding the potential to the Lagrangian through the metric of background space-time. The results of the model are compared with another model and the differences are discussed.Comment: 14 pages,8 figure

    No Tradeoff between Coherence and Sub-Poissonianity for Heisenberg-Limited Lasers

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    The Heisenberg limit to laser coherence C\mathfrak{C} -- the number of photons in the maximally populated mode of the laser beam -- is the fourth power of the number of excitations inside the laser. We generalize the previous proof of this upper bound scaling by dropping the requirement that the beam photon statistics be Poissonian (i.e., Mandel's Q=0Q=0). We then show that the relation between C\mathfrak{C} and sub-Poissonianity (Q<0Q<0) is win-win, not a tradeoff. For both regular (non-Markovian) pumping with semi-unitary gain (which allows Q1Q\xrightarrow{}-1), and random (Markovian) pumping with optimized gain, C\mathfrak{C} is maximized when QQ is minimized.Comment: This is a companion letter to the manuscript entitled "Optimized Laser Models with Heisenberg-Limited Coherence and Sub-Poissonian Beam Photon Statistics", arxiv:2208.14082. 6 pages, 2 figure

    The Heisenberg limit for laser coherence

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    To quantify quantum optical coherence requires both the particle- and wave-natures of light. For an ideal laser beam [1,2,3], it can be thought of roughly as the number of photons emitted consecutively into the beam with the same phase. This number, C\mathfrak{C}, can be much larger than μ\mu, the number of photons in the laser itself. The limit on C\mathfrak{C} for an ideal laser was thought to be of order μ2\mu^2 [4,5]. Here, assuming nothing about the laser operation, only that it produces a beam with certain properties close to those of an ideal laser beam, and that it does not have external sources of coherence, we derive an upper bound: C=O(μ4)\mathfrak{C} = O(\mu^4). Moreover, using the matrix product states (MPSs) method [6,7,8,9], we find a model that achieves this scaling, and show that it could in principle be realised using circuit quantum electrodynamics (QED) [10]. Thus C=O(μ2)\mathfrak{C} = O(\mu^2) is only a standard quantum limit (SQL); the ultimate quantum limit, or Heisenberg limit, is quadratically better.Comment: 6 pages, 4 figures, and 31 pages of supplemental information. v2: This paper is now published [Nature Physics DOI:10.1038/s41567-020-01049-3 (26 October 2020)]. For copyright reasons, this arxiv paper is based on a version of the paper prior to the accepted (21 August 2020) versio

    Optimized Laser Models with Heisenberg-Limited Coherence and Sub-Poissonian Beam Photon Statistics

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    Recently it has been shown that it is possible for a laser to produce a stationary beam with a coherence (quantified as the mean photon number at spectral peak) which scales as the fourth power of the mean number of excitations stored within the laser, this being quadratically larger than the standard or Schawlow-Townes limit [1]. Moreover, this was analytically proven to be the ultimate quantum limit (Heisenberg limit) scaling under defining conditions for CW lasers, plus a strong assumption about the properties of the output beam. In Ref. [2], we show that the latter can be replaced by a weaker assumption, which allows for highly sub-Poissonian output beams, without changing the upper bound scaling or its achievability. In this Paper, we provide details of the calculations in Ref. [2], and introduce three new families of laser models which may be considered as generalizations of those presented in that work. Each of these families of laser models is parameterized by a real number, pp, with p=4p=4 corresponding to the original models. The parameter space of these laser families is numerically investigated in detail, where we explore the influence of these parameters on both the coherence and photon statistics of the laser beams. Two distinct regimes for the coherence may be identified based on the choice of pp, where for p>3p>3, each family of models exhibits Heisenberg-limited beam coherence, while for p<3p<3, the Heisenberg limit is no longer attained. Moreover, in the former regime, we derive formulae for the beam coherence of each of these three laser families which agree with the numerics. We find that the optimal parameter is in fact p4.15p\approx4.15, not p=4p=4.Comment: This is a companion manuscript to the letter entitled "No Tradeoff between Coherence and Sub-Poissonianity for Heisenberg-Limited Lasers", arxiv:2208.14081. 22 pages, 11 figure

    Isolation and typing of the influenza viruses in the Caspian littoral of Iran

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    Present study introduces results of common influenza virus strains in the north of Iran. Samples collected from 65 patients with acute respiratory illness by throat washing and swabs, randomly from north of Iran (Mazandaran, Golestan and Guilan provinces). The patients suffered from fever (high), cough, sore throat, general malaise, chill and myalgia. Viruses were isolated by cell culture and confirmed with HA (Hemagglutination) test and then typed by and HI (Hemagglutination Inhibition) test. Out of 65 throat samples, 12 influenza viruses were isolated and typed. Isolated viruses belonged to A (H1N1), A (H3N2) and B influenza viruses. This study showed that Influenza viruses displayed identical pattern to other provinces in Iran and to other countries. To fight against epidemics and pandemics, we should collect enough data about status of influenza each year and data of exact vaccine formulation application for use in different areas of the world. Acquired data has shown that the vaccine for above viruses that confirmed by WHO can result in decreased risks of influenza in at risk cases in provinces of north Iran

    A survey on fopid controllers for lfo damping in power systems using synchronous generators, facts devices and inverter-based power plants

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    In recent decades, various types of control techniques have been proposed for use in power systems. Among them, the use of a proportional–integral–derivative (PID) controller is widely recognized as an effective technique. The generalized type of this controller is the fractional-order PID (FOPID) controller. This type of controller provides a wider range of stability area due to the fractional orders of integrals and derivatives. These types of controllers have been significantly considered as a new approach in power engineering that can enhance the operation and stability of power systems. This paper represents a comprehensive overview of the FOPID controller and its applications in modern power systems for enhancing low-frequency oscillation (LFO) damping. In addition, the performance of this type of controller has been evaluated in a benchmark test system. It can be a driver for the development of FOPID controller applications in modern power systems. Investigation of different pieces of research shows that FOPID controllers, as robust controllers, can play an efficient role in modern power systems
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