116 research outputs found

    EFFECTS OF APPROACH VELOCITY TO THE CONTRIBUTION OF EACH BODY SEGMENTS TO THE TAKE-OFF MOVEMENT IN THE LONG JUMP

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    INTRODUCTION Much study suggested that approach velocity gave significant effects to the long jump performance However, there are very few studies effects of approach velocity to the role or the contribution of each body segments to the take-off movement in the long Jump, which is the purpose of this study Nine male long jumpers performed the long jump of the three types, Slow jump (S 10----15m-approachrun), Medium jump (M 25----30m-approachrun), Fast jump (F full approach of their own). Their take-off motions were filmed at 200Hz with Nac high speed camera. Two dimensional coordinates were obtained by digitizing the motions with a sampling frequency of 200Hz. The data was filtered with a Butterworth digital filter(Winter 1979) at 10Hz BSP of Chandler et al. (1975) were used to estimate the segmental centers of gravity and mass center of the whole body This data used to calculate the generated momenta and impulses (horizontal, vertical) of the arms (A), trunk (T: head and trunk), free leg (F) and take-off leg (TL), using the method of Ae and Shibukawa (1980). The mean percent contribution of the segments were obtained by dividing total impulse of each segment over the take-off phase by the whole body impulse RESULTS With the regard to the horizontal direction, the body segments contribution suggested the same proportion pattern all of the three types jumps. The highest (positive) contribution was made by the trunk (S: 4155±22.5%, M36.42± 18.23%, F54.85 ± 3024%) The contribution of the arms (S -5.97±281%, M:-6.34±5.21%, F:-9.54± 6.20%), The free leg (S: -5.85±481%, M: -1603±1120%, F: -722±3.10%) and take-off leg (S:-129.73±35.59%, M -11405±48.47%, F:-138.10±6550%) were negative. Most negative contribution was made by the take-off leg As for the vertical direction, the all body segments contribution of the three types jumps showed positive contribution (S; A 4.29±262%, T 4.06±423%, FL 0.69± 2.44%, TL 90 96±7.82%, M; A 600± 1.60%, T 9.54±9.37%, FL 010±210%, TL 84.36±11.14%, F; A 10.5±3.12%, T 8.02±604%, FL: 2.88±1.01%, TL 78.60 ± 14.56%). The take-off leg showed the highest percentage contribution As the approach velocity increased, so did the contribution of the arms, while the contribution of the take-off leg decreased. CONCLUSION With regard to the horizontal direction, the body segments contribution showed the same proportion pattern in all of the three types jumps The trunk made positive contribution to horizontal velocity, the trunk made positive contribution to horizontal velocity, the other body segments made negative contribution to horizontal velocity in horizontal direction. On the other hand, as the approach velocity increased, so did the contribution of the arms, while the contribution of the take-off leg decreased. The arms and take-off leg have a mutually supportive relationship in vertical direction

    Gamma Ray Spectroscopy with Scintillation Light in Liquid Xenon

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    Scintillation light from gamma ray irradiation in liquid xenon is detected by two Hamamatsu R9288 photomultiplier tubes (PMTs) immersed in the liquid. UV light reflector material, PTFE, is used to optimize the light collection efficiency. The detector gives a high light yield of 6 photoelectron per keV (pe/keV), which allows efficient detection of the 122 keV gamma-ray line from Co-57, with a measured energy resolution of (8.8+/-0.6)% (sigma). The best achievable energy resolution, by removing the instrumental fluctuations, from liquid xenon scintillation light is estimated to be around 6-8% (sigma) for gamma-ray with energy between 662 keV and 122 keV

    Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

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    Recently CMOS Active Pixels Sensors (APSs) have become a valuable alternative to amorphous Silicon and Selenium Flat Panel Imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ≀ 1.9%. The uniformity of the image quality performance has been further investigated in a typical X-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practise. Finally, in order to compare the detection capability of this novel APS with the currently used technology (i.e. FPIs), theoretical evaluation of the Detection Quantum Efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this detector compared to FPIs. Optical characterization, X-ray contrast measurements and theoretical DQE evaluation suggest that a trade off can be found between the need of a large imaging area and the requirement of a uniform imaging performance, making the DynAMITe large area CMOS APS suitable for a range of bio-medical applications

    Inversion analysis of the 2004 off the Kii peninsula earthquakes using seismic intensity data

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    Ung och tanklös Àr en litteraturstudie som handlar om pÄföljdssystemet för unga lagövertrÀdare. Den ger en översikt över dagens pÄföljdssystem samt en historisk tillbakablick inom lagstiftningen och ÄtgÀrderna kring unga lagövertrÀdare i Sverige. Syftet med uppsatsen Àr att undersöka hur dagens samhÀlle hanterar unga lagövertrÀdare. Varför ser vÄrt pÄföljdssystem ut som det gör? Tyngdpunkten i arbetet ligger pÄ utvecklingen av pÄföljderna samt att det har gÄtt frÄn straff till ett mer behandlingsinriktat samhÀlle. Uppsatsen tar Àven upp sluten ungdomsvÄrd och hur straff och behandlig förenas pÄ institutionerna. De resultat som framkommer i uppsatsen Àr att de behandlingsmetoder som visat sig vara effektiva för gruppen unga lagövertrÀdare Àr Kognitiv beteendeterapi baserade program och familjebaserade insatser. De insatser som visats fungera bÀttre Àn andra utmÀrks genom att de inriktar sig pÄ att pÄverka den unges sÀtt att tÀnka, kÀnna och bete sig. Det innebÀr att det Àr mer effektivt att ge den unge nÄgon typ av kvalificerad behandling utöver en juridisk pÄföljd. Uppsatsen visar Àven en utveckling av olika slags pÄföljder för unga lagövertrÀdare eftersom olika straffteorier har tillÀmpats genom tiden. Samt hur samhÀllets ÄtgÀrder för unga lagövertrÀdare förÀndrats.Young and thoughtless is a literature which deals with penalties for young offenders. It gives an overview of the current system of sanctions and to history in the legislation and measures relating to young offenders in Sweden. The purpose of this paper is to examine how our society handles young offenders. Why does our system of penalties the way they do? The focus of the work lies in the development of the sanctions and that it has moved from criminal to a more treatment-oriented society. The essay also takes up secure youth and how punishment and treatment united in institutions. The results obtained in the paper is that the methods of treatment proved effective for the group of young offenders is cognitive-behavioral therapy-based programs and family-based interventions. The actions demonstrated work better than others, characterized by the focus on to influence the young person's way of thinking, feeling and behaving. That means it is more effective to give the kids some type of skilled therapy beyond a legal sanction. The essay also shows a development of different types of sanctions for young offenders because various criminal theories have been applied through time. And how society measures for young offenders has changed

    A novel camera type for very high energy gamma-ray astronomy based on Geiger-mode avalanche photodiodes

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    Geiger-mode avalanche photodiodes (G-APD) are promising new sensors for light detection in atmospheric Cherenkov telescopes. In this paper, the design and commissioning of a 36-pixel G-APD prototype camera is presented. The data acquisition is based on the Domino Ring Sampling (DRS2) chip. A sub-nanosecond time resolution has been achieved. Cosmic-ray induced air showers have been recorded using an imaging mirror setup, in a self-triggered mode. This is the first time that such measurements have been carried out with a complete G-APD camera.Comment: 9 pages with 11 figure

    Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

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    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2 x 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2 x 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of ≈\approx 0.170 ns for 15 cm axial field-of-view (AFOV) and ≈\approx 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.Comment: To be published in Phys. Med. Biol. (26 pages, 17 figures
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