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- Semchuk, O. Yu., et al.
(författare)
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Thermal effects caused by action of powerful laser radiation on condensed matter
- 2010
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Ingår i: JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS. - : Inoe and Infm. - 1454-4164. ; 12:3, s. 586-588
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Tidskriftsartikel (refereegranskat)abstract
- The spatial and temporal temperature distribution on a solid's surface heated by laser interference pattern is calculated using integral transformation on coordinates x, y and Fourier transformation on coordinate z . Two-dimensional periodic structure consisting of circles with radii equal to a radius of the laser beam is considered. It is shown, that the maximal heating is observed in the center of a circle while diminishing to periphery. The area where the intensive surface heating is observed extends up to 0.8 r/a ( a is a period of the grating, r is a radius of the laser beam).
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| 6. |
- Langholz, Janna Brit, 1990, et al.
(författare)
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Electromyographic analysis of the swim start: Bilateral comparison of the front-weighted and rear-weighted track start from the OMEGA OSB11 starting block
- 2015
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Ingår i: 3d Interational Congress on Sport Sciences Research and Technology Support, icSports 2015, Lisbon, Portugal.. - : SCITEPRESS - Science and and Technology Publications. - 9789897581595 ; , s. 310-320
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Konferensbidrag (refereegranskat)abstract
- Previous swim start studies involving electromyography (EMG) consistently comprised unilateral measurements and the attachment of the swimmer via cables to a computer. Therefore the present work aims for an overall picture of the muscle activation pattern during the swim start by conducting bilateral measurements with minimal restriction of motion. On that account a multichannel surface EMG device with a wireless Bluetooth connection and videography is utilized in order to assess the nowadays most common start dive techniques of competitive swimming events - differently weighted track starts from the OMEGA OSB11 starting block. The data analysis identified that the normalized muscle activation levels were higher during the front-weighted than during the rear-weighted start - probably caused by shorter block times and less contribution of the arms. Furthermore the onset of the muscle activation seems to be different in between start dive techniques, as for instance the muscles of the rear leg commence contracting earlier while the muscles of the front leg start later in the rear-weighted compared to front-weighted starts. It is highly likely that this originates in the position of the center of mass relative to the muscles. A general overview over the coordination of the different muscles could also be obtained: It became obvious that some muscles are the main drivers of the swim start (vastus lateralis, soleus) whereas others rather exerted supportive actions (gluteus maximus, semitendinosus, erector spinae longissimus).
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| 7. |
- Langholz, Janna Brit, 1990, et al.
(författare)
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Musculoskeletal modelling in sports - evaluation of different software tools with focus on swimming
- 2016
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Ingår i: Procedia Engineering. - : Elsevier BV. - 1877-7058 .- 1877-7058. ; 147, s. 281-287
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Konferensbidrag (refereegranskat)abstract
- Previous swim start measurements at Chalmers University of Technology involved electromyography (EMG) in order to get an overall picture of the muscle activation pattern during the swim start. In order to fully evaluate sports performance trainers may facilitate additional tools, like videography and force plates, to be able to underpin the feedback given to the athletes. However, the output of the different tools are often complicated and lengthy to handle. Therefore it would be valuable to find an easily applicable tool to visualize biomechanical data. Feedback to athletes based on scientifically measured variables would then ideally be more efficient and effective. This paper evaluates three different software tools regarding musculoskeletal modelling and simulation with quick, meaningful and unambiguous data processing and presentation: OpenSim, BoB and AnyBody. The software package SWUM was also analyzed as it is currently the only tool that can model forces and buoyancy during swimming. It has been found that OpenSim is a beneficial tool for academic projects as it is freely available and provides a big pool of users and papers available to support the user with additional knowledge. BoB is the most straight-forward tool being appropriate for biomechanical teaching and applications where a fast analysis is required. AnyBody has the most sophisticated model which can be adjusted to the users demands in great detail and is favorable for investigations with focus on the interaction between the body and the environment or a detailed medical analysis. Great potential lies in the further development and usage of SWUM as its basic interface with valuable outputs and simulations as well as the possibility of connecting to AnyBody might allow for advancements in swim training.
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| 8. |
- Papadopoulou, Panagiota, 1992, et al.
(författare)
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Investigation of Synthetic Clay Court’s Response under Cyclic Loading
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The synthetic clay tennis court’s properties need to be examined and modified to converge towards the playing characteristics of the natural clay tennis court. The aim of this study was to investigate the responses of three distinct carpet-material combinations and evaluate how the materials’ alteration affected the results. The specimens were compressed uniaxially up to 2 kN at 400 N/s loading rate at varying number of cycles. Energy transformation, strain accumulation, step of strain accumulation and moduli of each surface combination were calculated. Results indicated that the measurements were affected by the loading history and that the carpet modification influenced mainly the energy transformation and the strain accumulation, while the material change affected additionally the moduli of the system. Conduction of the experiments enhanced understanding of the clay court’s response and could attribute to the initial modelling of the synthetic clay surface.
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| 9. |
- Semchuk, OY, et al.
(författare)
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Laser-surface nanostructures in carbon coating
- 2005
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Ingår i: Fullerenes, nanotubes, and carbon nanostructures. - : Taylor and Francis. - 1536-383X .- 1536-4046. ; 13, s. 331-337
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we propose a theoretical basis of a new method of Laser Ablation Lithography (LAL) using coherent laser beams interference patterns. The advantage of our method is the absence of the need to use a mask. In our method the profile of nanostructures surface in carbon coating is produced by an interference laser beam pattern and depends on the following parameters: angle of beams convergence, phase difference, and intensity of the beams, and so forth.
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| 10. |
- Semchuk, OY, et al.
(författare)
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Wave function and quasi-energy of conduction electrons in a field of coherent light beams
- 2004
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Ingår i: Physica status solidi. B, Basic research. - : John Wiley andamp;amp; Sons, Ltd. - 0370-1972 .- 1521-3951. ; 241:11, s. 2549-2554
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Tidskriftsartikel (refereegranskat)abstract
- In this work the influence of high-frequency coherent light beams (CLB) on the motion of conduction electrons in a crystalline phase is studied. The wave function and the quasi-energy of conduction electrons are calculated. It is shown that a force that is associated with a pressure from the CLB influences the conduction electrons. A new approach to construct the kinetic equation, that takes into account the effects due to a CLB field that acts as the elementary processes for quasi-particle interaction in a crystalline phase, is presented.
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