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6792. Dy:PbGa2S4laser
- Creator:
- Csanaková, Bianka, Jelínková, Helena, Doroshenko, Maxim E., Badikov, Valerii V., Vyhlídal, David, Šulc, Jan, Němec, Michal , and Čech, Miroslav
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- solid-state lasers, MID-IR radiation, dysprosium, PbGa2 S4 material, Dy:PbGa2 S4 laser, Nd:YAG, atmospheric window, pevnolátkové lasery, MID-IR žiarenie, dysprózium, PbGa2 S4 materiál, Dy:PbGa2 S4 laser, and atmosférické okno
- Language:
- Czech
- Description:
- Mid-infrared region (2-8) μm is currently in the focus of laser physics, which is trying to develop new materials capable of generating coherent laser radiation in this region. This point of interest is connected to the so called infrared atmospheric window which offers new possibilities for solid-state lasers to be used as radars, LIDARs, tools for atmosphere diagnostics, etc. One of these new materials is the dysprosium doped lead-thiogallate (Dy:PbGa2 S4 ). In this article, we present brief characteristics of this laser active medium from the point of view of laser physics and we demonstrate the output radiation characteristics of three laser systems with dysprosium doped lead-thiogallate as their active media generating radiation at 2400 nm, 4300 nm a 5400 nm. The spatial structure, energy, impulse length and emission spectra of the output radiation were determined. and Stredná infračervená oblasť (2-8) μm je v súčasnosti terčom záujmu laserovej fyziky, ktorá sa snaží vyvinúť nové materiály, ktoré by mohli poskytovať koherentné laserové žiarenie v tejto oblasti. Tento záujem sa spája s existenciou tzv. infračerveného atmosférického okna, ktoré otvára nové možnosti aplikácií laserov generujúcich žiarenie v tejto oblasti ako sú radary, LIDARy, prostriedky pre diagnostiku atmosféry a podobne. Jedným z týchto nových materiálov majúcich takéto vlastnosti je dyspróziom dopovaný olovo-thiogalát (Dy:PbGa2 S4 ). V tomto článku prezentujeme stručnú charakteristiku tohto laserového aktívneho prostredia z pohľadu laserovej fyziky a demonštrujeme vlastnosti troch laserových systémov, obsahujúcich Dy:PbGa2 S4 ako aktívne médium, generujúcich žiarenie na vlnových dĺžkach 2400 nm, 4300 nm a 5400 nm. Výstupné žiarenie charakterizujeme z hľadiska priestorovej štruktúry, energie, dĺžky impulzu a emisného spektra.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6793. Dynamic analysis of mechatronic drive system with ansynchronous motor
- Creator:
- Mężyk, Arkadiusz, Bachorz, Pawel, and Świtoński, Eugeniusz
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dynamic model, electromechanical system, vector control, and optimization
- Language:
- English
- Description:
- The paper presents results of investigations on modeling and optimizing dynamic features of drive systems in order to minimize amplitudes of forces occurring in kinematic pairs of an electromechanical system with an ansynchronous motor and a vector control unit. The genetic algorithm was applied for optimization of design features of the system. The obtained results of numerical calculations confirmed the accuracy of the applied models and research methods for estimation of dynamic feature of drive systems. The set of design variables selected in the optimization process contained parameters describing design features of gear shafts and settings of control units. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6794. Dynamic analysis of the ring spinning process
- Creator:
- Beran, Jaroslav
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- ring spinning, yarn balloon, and balloon control ring
- Language:
- English
- Description:
- In this paper, the theory of the ballooning yarn has been adapted to the ring spinning process. The effect of the balloon control ring was incorporated into the mathematical model. The control ring is modeled as a frictionless circle constraint on the yarn path in the balloon.The balloon shape os determined by taking into account all the significant phenomena. The method of solution is applicable to more than one control ring in the threadline. The results from dynamic analysis are presented and show a marked effect of balloon control ring in reduce the yarn tension. The developed numerical solution procedures can be used to explore the regions of instability of the balloon. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6795. Dynamic approach to optimum synthesis of a four-bar mechanism using a swarm intelligence algorithm
- Creator:
- Portilla-Flores, Edgar A., Calva-Yáñez, Maria B., Villareal-Cervantes, Miguel G., Niño Suárez, Paola A., and Sepúlveda-Cervantes, Gabriel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- synthesis, four-bar mechanism, and M-ABC algorithm
- Language:
- English
- Description:
- This paper presents a dynamic approach to the synthesis of a crank-rocker four-bar mechanism, that is obtained by an optimization problem and its solution using the swarm intelligence algorithm called Modified-Artificial Bee Colony (M-ABC). The proposed dynamic approach states a mono-objective dynamic optimization problem (MODOP), in order to obtain a set of optimal parameters of the system. In this MODOP, the kinematic and dynamic models of the whole system are consider as well as a set of constraints including a dynamic constraint. The M-ABC algorithm is adapted to solve the optimization problem by adding a suitable constraint-handling mechanism that is able to incorporate the kinematic and dynamic constraints of the system. A set of independent computational runs were carried out in order to validate the dynamic approach. An analysis from the mechanical and computational point of view is presented, based on the obtained results. From the analysis of the simulation and its results, it is shown that the solutions for the proposed algorithm lead to a more suitable design based on the dynamic approach.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6796. Dynamic changes of orexin A and leptin in obese chldren during body weight reduction
- Creator:
- Jiří Bronský, Jara Nedvídková, Hana Zamrazilová, Martina Pechová, Martin Chada, Karel Kotaška, Jiří Nevoral, and Richard Průša
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, obezita, leptin, výživa dětí, physiology, obesity, children's nutrition, orexin A, hypocretin 1, 14, and 612
- Language:
- English
- Description:
- In this study, we describe changes of plasma levels of the hypothalamic neuropeptide orexin A in obese children during the reduction of body weight and its relationship to other biochemical and anthropometrical parameters. We measured orexin A fasting plasma levels by the RIA method in 58 obese children - 33 girls and 25 boys; mean age 13.1±0.38 years (range 7-18.5) before and after 5 weeks of weight-reduction therapy. Leptin, IGF-1, and IGFBP-3 levels were measured in all the subjects and were compared to orexin A levels and anthropometrical data. Average weight in subjects before weight-reduction was 74.2±2.79 kg and after weight-loss 67.4±2.60 kg (p<0.0001). Orexin A levels before the therapy were 33.3±1.97 pg/ml and after the therapy 51.7±3.07 pg/ml (p<0.0001). Levels of orexin A were not significantly different between girls and boys (p=0.7842). We found negative correlation between orexin A and age (r = -0.5395; p<0.0001), body height (r = -0.4751; p=0.0002), body weight (r = -0.4030; p=0.0017) and BMI (r = -0.2607; p=0.0481). No correlation was found between orexin A and IGF-1, IGFBP-3 or leptin. Orexin A plasma levels increased during body weight loss, whereas the reverse was true for leptin levels. These findings support the hypothesis that orexin A may be involved in regulation of nutritional status in children., J. Bronský, J. Nedvídková, H. Zamrazilová, M. Pechová, M. Chada, K. Kotaška, J. Nevoral, R. Průša., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6797. Dynamic changes of photosynthetic pigments in soybean callus under high irradiance
- Creator:
- Pandey, D. M., Kim, K.-H., and Yeo, U.-D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll, Glycine max, HPLC, photoinhibition, spectrophotometry, violaxanthin, and zeaxanthin
- Language:
- Multiple languages
- Description:
- Dynamic changes of neoxanthin (NEO), violaxanthin (VIO), anteraxanthin (ANT), zeaxanthin (ZEA), chlorophyll (Chl) a, Chl b, α-carotene, β-carotene, and their behaviour under increasing duration of high irradiance (HI) were investigated in the soybean hypocotyl callus culture. The calli were induced on solid (1.1 % agar) MS medium (pH 5.8) supplemented with 4.52 μM 2,4-D, 2.32 μM kinetin, and 3 % sucrose. After 30 d of culture, the green calli were irradiated with "white light" (133W m-2) for 0, 3.5, and 24 h. HPLC profiles were separated on a C18 column. With increasing duration of HI, the content of total carotenoids (Cars) increased, but the ratio of Chl a+b/Cars decreased. With lengthening the duration of HI, there was induction of ZEA. Contents of ANT, α-carotene, and β-carotene remained nearly constant, but ratio of ZEA/Chl a+b increased with lengthening the HI duration. and D. M. Pandey, K. H. Kim, U. D. Yeo.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6798. Dynamic coverage control design of multi-agent systems under ellipse sensing regions
- Creator:
- Ma, Longbiao, He, Fenghua, Wang, Long, Ji, Denggao, and Yao, Yu
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- coverage, multi-agent systems, region reconnaissance, and ellipse sensing region
- Language:
- English
- Description:
- This paper studies the dynamic coverage control problem for cooperative region reconnaissance where a group of agents are required to reconnoitre a given region. The main challenge of this problem is that the sensing region of each agent is an ellipse. This modeling results in asymmetric(directed) interactions among agents. First, the region reconnaissance is formulated as a coverage problem, where each point in the given region should be surveyed until a preset level is achieved. Then, a coverage control law is designed that minimizes coverage performance index by finite switches between nominal control laws and perturbation control law. Finally, numerical simulations are provided to indicate the efficiency of the proposed control law.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6799. Dynamic deformations and stresses of beams connected by damping element
- Creator:
- Půst, Ladislav
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- beam vibration, damping, modes of forced vibration, and stress in roots
- Language:
- English
- Description:
- Dynamic properties of two similar, parallel, one-sided clamped beams connected by a damping element on their free ends are analytically and numerically investigated. A harmonic motion excites the end of one of these beams. The main attention is given to the ascertaining of response curves deflection shapes of beams and their stresses in roots at different orientations and levels of damping force. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6800. Dynamic dependence ordering for Archimedean copulas and distorted copulas
- Creator:
- Charpentier, Arthur
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Archimedean copulas, Cox model, dependence, distorted copulas, and ordering
- Language:
- English
- Description:
- This paper proposes a general framework to compare the strength of the dependence in survival models, as time changes, i.e. given remaining lifetimes X, to compare the dependence of X given X>t, and X given X>s, where s>t. More precisely, analytical results will be obtained in the case the survival copula of X is either Archimedean or a distorted copula. The case of a frailty based model will also be discussed in details.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public