1,103 research outputs found

    Development of a Chaff Dispense Program for Target Tracking Radar Deception

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    This study aims to develop an appropriate chaff dispensing program to deceive the target tracking radar (TTR) effectively. Chaff is a countermeasure commonly used by fighter aircraft to deceive TTR. However, there has been a lack of methodology for calculating chaff dispense programs that take into account the specific characteristics of the fighter, chaff, and TTR. This study proposes a methodology that considers these variables to calculate chaff dispense programs and addresses this gap. The proposed method is demonstrated through TESS engagement, which shows its effectiveness in various engagement situations

    Development of a Chaff Dispense Program for Target Tracking Radar Deception

    Get PDF
    This study aims to develop an appropriate chaff dispensing program to deceive the target tracking radar (TTR) effectively. Chaff is a countermeasure commonly used by fighter aircraft to deceive TTR. However, there has been a lack of methodology for calculating chaff dispense programs that take into account the specific characteristics of the fighter, chaff, and TTR. This study proposes a methodology that considers these variables to calculate chaff dispense programs and addresses this gap. The proposed method is demonstrated through TESS engagement, which shows its effectiveness in various engagement situations

    Timing of intravenous immunoglobulin treatment and outcome in Guillain-Barré syndrome: is time nerve?

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    Introduction/Aims: Despite treatment, a considerable proportion of patients with Guillain–Barré syndrome (GBS) experience poor recovery, highlighting a therapeutic need. There is a lack of evidence that treatment timing affects recovery. This study aims to investigate the effects of intravenous immunoglobulin (IVIg) timing on disability and speed of recovery in GBS. Methods: We performed a retrospective study of 136 IVIg-treated GBS patients admitted to two Korean centers between 2010 and 2021. We analyzed the effect of time to IVIg on the GBS disability scale (GBS-DS) and the degree of improvement from nadir (∆GBS-DS) at 1, 3, 6, and 12 months, as well as the time to regain the ability to walk or run unaided. Time to IVIg was treated either as a continuous variable or categorized into 1-week intervals to explore critical time windows. Known prognostic factors, the modified Erasmus GBS Outcome Scores on admission and pre-treatment serum albumin levels were adjusted as covariates. Results: Shorter time to IVIg was independently associated with better GBS-DS, greater ∆GBS-DS, and shorter time to walk or run unaided at all time points. The therapeutic effect of IVIg was notably diminished when administered beyond the first 2 weeks of onset. Discussion: Our study highlights the timing of IVIg as a modifiable prognostic factor in GBS. The earlier IVIg is initiated, the better the outcomes, with the ideal time window being within the first 2 weeks. These findings underscore the importance of prompt diagnosis and early intervention to optimize recovery in GBS patients

    Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature

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    Transparent electronic materials are increasingly in demand for a variety of optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys. Express. 5, 061102 (2012)]. Following that work, we report various physical properties of (Ba,La)SnO3 single crystals and films including temperature-dependent transport and phonon properties, optical properties and first-principles calculations. We find that almost doping-independent mobility of 200-300 cm^2(Vs)^-1 is realized in the single crystals in a broad doping range from 1.0x10^19 to 4.0x10^20 cm^-3. Moreover, the conductivity of ~10^4 ohm^-1cm^-1 reached at the latter carrier density is comparable to the highest value. We attribute the high mobility to several physical properties of (Ba,La)SnO3: a small effective mass coming from the ideal Sn-O-Sn bonding, small disorder effects due to the doping away from the SnO2 conduction channel, and reduced carrier scattering due to the high dielectric constant. The observation of a reduced mobility of ~70 cm^2(Vs)^-1 in the film is mainly attributed to additional carrier-scatterings which are presumably created by the lattice mismatch between the substrate SrTiO3 and (Ba,La)SnO3. The main optical gap of (Ba,La)SnO3 single crystals remained at about 3.33 eV and the in-gap states only slightly increased, thus maintaining optical transparency in the visible region. Based on these, we suggest that the doped BaSnO3 system holds great potential for realizing all perovskite-based, transparent high-frequency high-power functional devices as well as highly mobile two-dimensional electron gas via interface control of heterostructured films.Comment: 31 pages, 7 figure

    Gender differences in the distal radial artery diameter for the snuffbox approach

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    Background: Recently, interventional cardiologists have been increasingly interested in snuffbox approach for coronary angiography (CAG) and percutaneous coronary intervention (PCI). However, there is lack of data regarding distal radial artery (RA) diameter according to gender. Therefore, the aim herein was to investigate gender differences in the diameter of distal RA diameter. Methods: Left snuffbox approach was done in 117 patients who had planned CAG or PCI for suspected myocardial ischemia between 1 December 2017 and 28 February 2018 at the Chonnam National University Hospital, Gwangju, Korea. Left RA angiography was achieved from 101 patients. Among 101 individuals, 69 (68.3%) men and 32 (31.7%) women were enrolled. There was no significant difference in systolic and diastolic blood pressure, body mass index, left ventricular systolic function, or patients with acute coronary syndrome in either group. Results: The average diameter of distal RA was 2.57 mm in all patients. Women had a significantly smaller diameter of distal RA than men (2.40 mm vs. 2.65 mm, p = 0.016). Nevertheless, CAG via snuffbox approach by 6 Fr sheath was successfully performed in all 117 patients. Regarding success rate of the distal RA approach, women had a lower success rate (32/38) compared with men (72/79), but not significantly (84.2% vs. 91.1%, p = 0.264). Conclusions: Females has a significantly smaller distal RA diameter compared to males. Moreover, the success rate of the distal RA approach tends to be higher in men than in women
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