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101.
Several different microorganisms have been suggested for coal desulfurization. In the present investigation, the thermophilic archaea Acidianus brierleyi (DSM 1651), Sulfolobus acidocaldarius (DSM 639) and Sulfolobus solfataricus (DSM 1616) were compared with the mesophilic bacterium Thiobacillus ferrooxidans (DSM 583) concerning their capability of removing sulfur from coal. The desulfurization rate as well as the amount of sulfur removed by the microorganisms was studied.

Two of the investigated microorganisms, Thiobacillus ferrooxidans and Acidianus brierleyi, were capable of oxidizing pure pyrite as well as oxidizing sulfur in coal. A kinetic analysis was performed assuming first order reactions. The rate constant for oxidation of pure pyrite by A. brierleyi was observed to be higher than for T. ferrooxidans. The values of the rate constants for sulfur removal from coal were comparable for the two microorganisms, but were higher than for oxidation of pure pyrite.  相似文献   

102.
Simultaneous Hall and conductivity measurements have been performed on sputtered polycrystalline thin films and on bulk ceramic specimens of nearly stoichiometric CeO2 in the temperature range between 900° and 1040°C. The measurements have been performed in air using low-frequency alternating current. In the case of the bulk ceramic specimens, an upper limit for the carrier mobility of ≤0.2 cm2/(V·s) has been obtained, which is in accordance with data from the literature for bulk samples. The conductivity of the thin films (l/1Ω·m) at 1000°C) is in accordance with data from the literature for bulk ceramics. The carrier density derived from the Hall measurements (3 × 1016/cm3 at 1000°C) increases with increasing temperature, whereas the Hall mobility (4 cm2(V·s) at 1000°C) decreases with increasing temperature. These values differ from literature data for bulk ceramic specimens. The difference may be duelo the small grain diameters (∼200 nm) in the 1-μm-thick thin films.  相似文献   
103.
Wet clutches operating under low velocity and high load are studied with the aim of obtaining reliable models for the torque transfer during boundary lubrication conditions. A friction model which takes temperature, speed and nominal pressure into account is developed and used with temperature calculations to be able to simulate behavior of a wet clutch working in boundary lubrication regime. Predicted torque and temperatures from the model agree well with experimental data.  相似文献   
104.
一、前言 在过去10年中,螺杆压缩机在天然气工业中的应用稳步增长,且继续呈上升趋势。这主要是因为许多陈旧的天然气油田中气体压力下降,从而使安装和使用往复式压缩机不再经济。今天,在脱硫气(不含硫化氢)和含硫气(含硫化氢)油田中都可看到螺杆压缩机,它们安装在井口,将天然气从地下抽拔上来,经过加压后送入输气管中。  相似文献   
105.
Sharp indentation test have been studied very frequently in recent years and the fundamental knowledge of the mechanics of such test has reached some maturity. Such studies also include the correlation between residual stresses and the global properties, i.e., hardness and size of the contact area. The investigations presented have been based on experimental, theoretical, and numerical methods and as a result, the basic features of the problem are fairly well understood but quantitative relations, for the determination of residual stresses using sharp indentation, have been proven to be less accurate and accordingly not suitable for a practical situation, in particular so at predominantly compressive residual stresses. It is therefore the aim of the present study to investigate this matter in some detail and to determine possible mechanisms for the difference in indentation behavior between tension and compression and, with this as a background, determine relations suitable for a quantitative determination of the residual fields. The present analysis is based on theoretical and numerical methods and in the latter case, the finite element method is relied upon. Classical Mises elastoplastic material behavior is assumed throughout the investigation.  相似文献   
106.
Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was performed on the laser-machined polymer using an Alicona InfiniteFocus? microscope. Based on previous experiments, bearing area curve and its parameters are chosen to characterize the surface. In this paper, by comparison of plateable and non-plateable surfaces, and two types of plateable surface made by different lasers, it is found that the normalized bearing area curve is an effective method to characterize porous surface for the subsequent plating. The normalized parameters are available to make a quantitative analysis.  相似文献   
107.
Chinese TLV-bronze mirrors dating to the Han dynasty (206 B.C.-220 A.D.) were popular objects of everyday life as well as highly esteemed works of art. The decorated back of the mirror characterizes the culture of this period as well as the excellent early Chinese casting techniques.  相似文献   
108.
During fluorescent live cell imaging it is critical to keep excitation light dose as low as possible, especially in the presence of photosensitizer drugs, which generate free radicals upon photobleaching. During fluorescent imaging, stress by excitation and free radicals induces serious cell damages that may arrest the cell cycle. This limits the usefulness of the technique for drug discovery, when prolonged live cell imaging is necessary. This paper presents a strategy to provide gentle experimental conditions for dynamic monitoring of the proliferation of human lung epithelial carcinoma cells (A549) in the presence of the photosensitizer Polyvinylpyrrolidone-Hypericin. The distinctive strategy of this paper is based on the stringent environmental control and optimizing the excitation light dose by (i) using a low-power pulsed blue light-emitting diode with short pulse duration of 1.29 ms and (ii) adding a nontoxic fluorescent dye called carboxyfluorescein-diacetate-succinimidyl-ester (CFSE) to improve the fluorescence signals. To demonstrate the usefulness of the strategy, fluorescence signals and proliferation of dual-marked cells, during 5-h fluorescence imaging under pulsed excitation, were compared with those kept under continuous excitation and nonmarked reference cells. The results demonstrated 3% cell division and 2% apoptosis due to pulsed excitation compared to no division and 85% apoptosis under the continuous irradiation. Therefore, our strategy allows live cell imaging to be performed over longer time scales than with conventional continuous excitation.  相似文献   
109.
A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of ~8 to ~120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.  相似文献   
110.
SPHERES is a third-generation neutron backscattering spectrometer, located at the 20 MW German neutron source FRM II and operated by the Ju?lich Centre for Neutron Science. It offers an energy resolution (fwhm) better than 0.65 μeV, a dynamic range of ±?31 μeV, and a signal-to-noise ratio of up to 1750:1.  相似文献   
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