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Spectral properties and identification of aerostatic bearings

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Acta Mechanica Sinica 2011年第1期27卷 63-67页

作者： Jan Kozánek Ladislav Pust institute of Thermomechanics AS cr

Modified rotor kit Bently Nevada was used for dynamic characteristics measurements of new developed aerostatic *** model of these bearings is considered as *** was identified with the help of harmonic force excitation independently from the speed of journal *** stiffness and damping matrices were identified for different air inlet *** calculated spectral properties allow to determine the stability boundary for suitable variation of model parameters.

关键词： Aerostatic bearing · Identification · Stiffness · Damping coefficients

A study of fire propagation in coal seam with numerical simulation of heat transfer and chemical reaction rate in mining field

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International Journal of Mining Science and Technology 2019年第6期29卷 873-879页

作者： Moisés Oswaldo Bustamante Rúa Alan José Daza Aragón Pablo Bustamante Baena National University of Colombia Cr 65 # 63 20 CIMEX Minerals Institute

Spontaneous combustion of coal is a problem that affects the mining operation and generates environ-mental,economic,social and geotechnical *** phenomenon has been divided into two pro-cesses:ignition and *** propagation develops in coal seams because of a set of factors such as direction and wind speed,fracturing and *** this work,heat transfer and chemical kinetics are studied from conservation equations of energy and species,respectively,using the software COMSOL Multiphysics to simulate the propagation of fires in coal *** possible scenarios were analyzed that usually occur in the walls of the coal seams,such as fire focus and fire complete *** was found that the propagation kinetics of the fire changes depending on the temperature,the fractur-ing of rock mass and the area of fire *** temperature values lower than 300℃,there is con-sumption around 250 cm^3/h,values around 700℃,the consumption is 1500 cm^3/h,and for fires of 1200℃ have values of 3000 cm^3/*** on the speed of propagation can vary from 4 to 17cm/day,considering on the level and fracturing of the final wall of the open pit.

关键词： Spontaneous combustion of coal Open pit mines Simulation Heat transfer Chemical reaction COMSOL

HOT DIPPING ALUMINIZED COATING AS HYDROGEN PERMEATION BARRIER

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 435-440页

作者： Z. Y Yao, M. Chini, A. Aiello and G. Benamati (China institute of Atomic Energy, P.O.Box 275-51, Beijing 1024l3, China) ( Department of Physics, University of Trento, 38100 Trento, Italy) ( ENEA cr Brasimone, 40032 Camugnano, Bologna, Italy) China institute of Atomic Energy Department of Physics University of Trento ENEA cr Brasimone

The hydrogen permeation experiment of MANET II with hot dipping aluminized coating was performed in temperature range of 573 to 623 K, in gas phase and in liquid Pb-17Li phase. The hydrogen permeation reduction factor (PRF) evaluated in gas phase is 620 at 573 K and 260 at 623 K, and in liquid Pb-17Li phase is 24-45 at 573 K and 12-30 at 623 K. The self-healing of coating is obvious and effective above 673 K. The pressure dependence of permeation flux indicates strong surface contribution. The way of filling hydrogen by continuous flow and/or bubble can increase permeation flux. The result of SEM-EDS shows that the microcrack is on the surface of the wetted part, but not on the not wetted part. The crack is superficial and affects only thin outside layer not penetrate aluminized layer. The surface elemental analysis shows that Al/O atomic ratio changes from 2/3 of not wetted part to about 1 of wetted part. The damage of coating surface seems to be related to the interaction of outside layer with liquid Pb-17Li and thermal stress during heating sample.

关键词： Electroless plating Hydrogen Maraging steel Mechanical permeability

Impact of microbial communities from tropical soils on the mobilization of trace metals during dissolution of cinnabar ore

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Journal of Environmental Sciences 2017年第6期29卷 122-130页

作者： Clarisse Balland-Bolou-Bi Benjamin Turc Vanessa Alphonse Noureddine Bousserrhine UniversitéParis-Est crùteil Val de Marne institute of Ecology and Enuironmental Sciences of Paris(UMR 7618)61 auenue du Général De Gaulle94010 Créteil cedexFrance

Biodissolution experiments on cinnabar ore （mercury sulphide and other sulphide minerals, such as pyrite） were performed with microorganisms extracted directly from soil. These experiments were carried out in closed systems under aerobic and anaerobic conditions with 2 different soils sampled in French Guyana. The two main objectives of this study were （1） to quantify the ability of microorganisms to mobilize metals （Fe, A1, Hg） during the dissolution of cinnabar ore, and （2） to identify the links between the type and chemical properties of soils, environmental parameters such as season and the strategies developed by indigenous microorganisms extracted from tropical natural soils to mobilize metals, Results indicate that microbial communities extracted directly from various soils are able to （1） survive in the presence of cinnabar ore, as indicated by consumption of carbon sources and, （2） leach Hg from cinnabar in oxic and anoxic dissolution experiments via the acidification of the medium and the production of low molecular mass organic acids （LMMOAs）. The dissolution rate of cinnabar in aerobic conditions with microbial communities ranged from 4.8 x 10-4 to 2.6 x 10-3 μmol/m2/day and was independent of the metabolites released by the microorganisms. In addition, these results suggest an indirect action by the microorganisms in the cinnabar dissolution. Additionally, because iron is a key element in the dynamics of Hg, microbes were stimulated by the presence of this metal, and microbes released LMMOAs that leached iron from iron-bearing minerals, such as pyrite and oxy-hydroxide of iron, in the mixed cinnabar ore.

关键词： Low molecular mass organic acidsCinnabar oreMicrobial communitiesTropical soils

Design of a kJ-class HiLASE laser as a driver for inertial fusion energy

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High Power Laser Science and Engineering 2014年第2期2卷 1-10页

作者： Antonio Lucianetti Magdalena Sawicka Ondrej Slezak Martin Divoky Jan Pilar Venkatesan Jambunathan Stefano Bonora Roman Antipenkov Tomas Mocek HiLASE Project Institute of Physics AS CR Na Slovance 2 18221 Prague Czech Republic CNR-IFN Via Trasea 7 35131 Padova Italy ELI Beamlines Project Institute of Physics AS CR Na Slovance 2 18221 Prague Czech Republic

We present the results of performance modeling of a diode-pumped solid-state HiLASE laser designed for use in inertial fusion energy power plants. The main amplifier concept is based on a He-gas-cooled multi-slab architecture similar to that employed in Mercury laser system. Our modeling quantifies the reduction of thermally induced phase aberrations and average depolarization in Yb3+:YAG slabs by a combination of helium cryogenic cooling and properly designed(doping/width) cladding materials.

关键词： ASE birefringence cryogenic cooling slab lasers thermooptic effects

Cavitation Rates in Water with Dissolved Gas and Other Impurities

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Journal of Thermal Science 2003年第2期12卷 151-156,170页

作者： PatrikZima Franti■ekMar■ík MilanSedlá■ institute of Thermomechanics Academy of Sciences of CRDolejkova 518200Praha 8Czech RepublicInstitute of ThermomechanicsAcademy of Sciences of CRDolejkova 518200Praha 8Czech RepublicSIGMA Research and Development InstituteJana Sigmunda 7978350 LutínCzech Republic

Our objective is a better understanding of the role of physical properties of real fluids in the thermodynamics of cavitation in impure water. An extension to the classical homogenous nucleation theory suitable for mixtures is presented in attempt to address the discrepancy between the theoretical predictions and practical observations of cavitation rates in water at normal temperatures. The extension takes into account the non-equilibrium (dissipative) effects involved in nuclei formation through a substance dependent correction coefficient to be determined experimentally. The theory of thermodynamic fluctuations is applied to derive the work of formation of a bubble nucleus. The value of the correction coefficient is estimated using preliminary experimental data from a convergent-divergent nozzle. An application of the results to the numerical prediction of the cavitation zones in a radial-flow water pump is shown.

关键词： cavitation homogeneous nucleation water dissolved gas impurities.

Comparative LIDT measurements of optical components for high-energy HiLASE lasers

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High Power Laser Science and Engineering 2016年第1期4卷 75-83页

作者： Jan Vanda Jan evcík Egidijus Pupka Mindaugas ciuka Andrius Melninkaitis Martin Divoky Venkatesan Jambunathan Stefano Bonora Václav koda Antonio Lucianetti Danijela Rostohar Tomas Mocek Valdas Sirutkaitis Hilase Institute of Physics AS CR LIDARIS Ltd. Laser Research Center Vilnius University LUXOR Laboratory CNR IFN crytur Ltd.

Further advancement of high-energy pulsed lasers requires a parallel development of appropriate optical *** different optical components, such as mirrors and antireflection-coated windows, which are essential for the design of Hi LASE high average power lasers were tested. The following paper summarizes results on the measurements of laser-induced damage threshold of such components, and clearly shows their capabilities and limitations for such a demanding application.

关键词： diode-pumped solid-state laser and applications laser-induced damage

Design of deformable mirrors for high power lasers

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High Power Laser Science and Engineering 2016年第2期4卷 68-74页

作者： Stefano Bonora Jan Pilar Antonio Lucianetti Tomas Mocek CNR-IFN HiLASE Centre Institute of Physics AS CR Department of Physical Electronics Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in Prague

We present the workflow of the design, realization and testing of deformable mirrors suitable for high power diode pumped solid-state lasers. It starts with the study of the aberration to be corrected, and then it continues with the design of the actuators position and characteristic. In this paper, we present and compare three deformable mirrors realized for multi-J level laser facilities. We show that with the same design concept it is possible to realize deformable mirrors for other types of lasers. As an example, we report the realization of a deformable mirror for femtosecond lasers and for a CW CO_2 laser.

关键词： adaptive optics closed loop deformable mirror high power lasers

Impact of Natural Oil-Based Recycled Polyols on Properties of Cast Polyurethanes

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Journal of Renewable Materials 2018年第7期6卷 697-706页

作者： Hynek Beneš Aleksandra Paruzel JiříHodan Olga Trhlíková institute of Macromolecular Chemistry AS cr v.v.i.Heyrovsky Sq.216206 Prague 6Czech Republic

In this study, castor oil, rapeseed oil and medium chain triglycerides of coconut oil, were transesterified bymeans of 2-ethyl-2-hydroxymethyl-1,3-propanediol (trimethylolpropane) and consequently used to convertpolycarbonate waste from end-of-life vehicles into liquid polyols. The prepared recycled polyols, composeduniquely of renewable and recycled components, had a hydroxyl number of ca. 250 mg KOH·g−1. They weresuccessfully applied as 100% replacement of a virgin polyol for preparation of solid crosslinked polyurethanes(PU) by solvent-free casting. The produced rigid cast PU exhibited the main transition temperature rangingfrom 44°C to 53°C, the hardness value from 46 to 61 Shore D and the beneficial low water absorption (0.4-0.5wt.%). The PU network structure was highly influenced by the presence of aromatic structures ofpolycarbonate-units and fatty acid compositions. A suitable selection of natural oil thus enabled to adjustthermo-mechanical properties and promote excellent optical transparency of the produced PU.

关键词： Natural oil cast polyurethane bio-based polycarbonate waste recycling