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141.
An injection seeded Nd:YAG laser oscillator has been set up and frequency stabilized following an rf-sideband scheme. This dual rod oscillator emits pulses with 23 ns duration and 20 mJ energy. The beam quality is almost diffraction limited (M(2)=1.2). The frequency stability was characterized with a heterodyne method to 1.0 MHz root mean square (rms). This oscillator will serve as the front end for a series of lidar devices for spectrally sensitive measurements. 相似文献
142.
M. Harraß Dipl.‐Chem. K. Strübbe K. Friedrich A. K. Schlarb J. Ensthaler T. Quirrenbach M. Bärmann N. Stasche 《Materialwissenschaft und Werkstofftechnik》2007,38(10):821-828
Integration of commercializing strategies in materials research ‐ model materials in medicine If a company is in a development process, the question raises which kinds of utilization should be used. Of prime importance is the decision, which properties of the product can be exploited most profitably. If it works, that the technology, which is in a development process yet, can be estimated in good time in regard to economical and legal risks and chances, these cognitions can be factored in cost efficient. Therewith, the possibilities of utilization should be considered as well as the profitability and the prospect of profits should be estimated. Therefore, several instruments of innovations analysis are used. In the present article, the integration of commercializing strategies in product development in the scope of medical engineering is shown. By the example of the development of an interventionable larynx model to the laser surgical professional education, technical, economical and legal aspects of valuation are brought together. 相似文献
143.
The article reports on low-temperature high-rate sputtering of hydrophilic transparent TiO2 thin films using dc dual magnetron (DM) sputtering in Ar + O2 mixture on unheated glass substrates. The DM was operated in a bipolar asymmetric mode and was equipped with Ti(99.5) targets
of 50 mm in diameter. The substrate surface temperature Tsurf measured by a thermostrip was less than 180 °C for all experiments. The effect of the repetition frequency fr was investigated in detail. It was found that the increase of fr from 100 to 350 kHz leads to (a) an improvement of the efficiency of the deposition process that results in a significant
increase of the deposition rate aD of sputtered TiO2 films and (b) a decrease of peak pulse voltage and sustaining of the magnetron discharge at higher target power densities.
It was demonstrated that several hundreds nm thick hydrophilic TiO2 films can be sputtered on unheated glass substrates at aD = 80 nm/min, Tsurf < 180 °C when high value of fr = 350 kHz was used. Properties of a thin hydrophilic TiO2 film deposited on a polycarbonate substrate are given. 相似文献
144.
Weschler CJ Wisthaler A Cowlin S Tamás G Strøm-Tejsen P Hodgson AT Destaillats H Herrington J Zhang J Nazaroff WW 《Environmental science & technology》2007,41(17):6177-6184
We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions: low air exchange (4.4 (h-1)), <2 ppb ozone; low air exchange, 61-64 ppb ozone; high air exchange (8.8 h(-1)), <2 ppb ozone; and high air exchange, 73-77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from approximately 70 to 130 ppb at the lower air exchange rate and from approximately 30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25-0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA. 相似文献
145.
Acceptable logic programs have been studied extensively in the context of proving termination of Prolog programs. It is difficult, however, to establish acceptability from the definition since this depends on finding a suitable model, which need not be a Herbrand model in general, together with a suitable level mapping that one can use to check the conditions which characterize acceptability. In this paper, we will see that when working over a fixed but arbitrary preinterpretation, a method can be provided for obtaining both a suitable model and a canonical level mapping which are sufficient for this purpose. Furthermore, the canonical model and level mapping obtained will turn out to be sufficient for discussing termination of non-ground queries. 相似文献
146.
Karel Michele J.; Molinari Victor; Gallagher-Thompson Dolores; Hillman Stephany L. 《Canadian Metallurgical Quarterly》1999,30(6):617
Have psychologists who have pursued postdoctoral training in geropsychology viewed such training as a worthwhile professional investment? As the population is aging, psychologists are increasingly working with older adults. For many psychologists, competent practice with the elderly will require some continuing education, whereas other psychologists may choose to secure specialty-level training in the field. A survey of psychologists who completed such specialized postdoctoral training found a high level of satisfaction with the training and a sense of professional competence in most of the geropsychology competency areas set forth by the American Psychological Association. The need for increased opportunities for both proficiency and specialty-level training in applied geropsychology is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
147.
Karel Komers Radek Stloukal Jaroslav Machek Frantiek Skopal 《European Journal of Lipid Science and Technology》2001,103(6):363-371
Detailed analysis is described of the samples taken after suitable reaction times from the actual reaction mixture during the production of biodiesel fuel using methanolysis of rapeseed oil catalyzed by KOH. Three methods for stoppage of reaction (neutralisation of catalyst, dilution by two suitable solvents) in the sample are used. The contents of mono‐, di‐ and triacylglycerols, methylesters of fatty acids (biodiesel) and potassium salts of fatty acids of rapeseed oil, glycerol (by HPLC method), basicity (by potentiometric titration) and water (by GC and Karl‐Fischer method) in the samples are determined. An example of these determinations is described. 相似文献
148.
Best prerequisites for long term stable optical coating are given by reactive Dual Magnetron Sputtering. Requirements for components and techniques for architectural Low‐E coating and TCO coating are discussed. Reliable process stabilization at high deposition rates is possible using Plasma Emission Monitor (PEM) control circuits. The use of multichannel PEM control allows a balance control to improve both the film thickness uniformity and reproducibility of working points for large area coating on glass or web. Examples of horizontal and vertical glass coater for deposition of optical multilayers for different applications are presented. 相似文献
149.
The transition from sexual reproduction to asexuality is often triggered by hybridization. The gametogenesis of many hybrid asexuals involves premeiotic genome endoreplication leading to bypass hybrid sterility and forming clonal gametes. However, it is still not clear when endoreplication occurs, how many gonial cells it affects and whether its rate differs among clonal lineages. Here, we investigated meiotic and premeiotic cells of diploid and triploid hybrids of spined loaches (Cypriniformes: Cobitis) that reproduce by gynogenesis. We found that in naturally and experimentally produced F1 hybrids asexuality is achieved by genome endoreplication, which occurs in gonocytes just before entering meiosis or, rarely, one or a few divisions before meiosis. However, genome endoreplication was observed only in a minor fraction of the hybrid’s gonocytes, while the vast majority of gonocytes were unable to duplicate their genomes and consequently could not proceed beyond pachytene due to defects in bivalent formation. We also noted that the rate of endoreplication was significantly higher among gonocytes of hybrids from natural clones than of experimentally produced F1 hybrids. Thus, asexuality and hybrid sterility are intimately related phenomena and the transition from sexual reproduction to asexuality must overcome significant problems with genome incompatibilities with a possible impact on reproductive potential. 相似文献
150.
Karel Klíma Dan Ulmann Martin Barto Michal panko Jaroslava Dukov Radka Vrbov Jan Pinc Jií Kubsek Marek Vlk Tereza Ulmannov Ren Foltn Eitan Brizman Milan Draho Michal Beo Vladimír Macho Jaroslav apek 《International journal of molecular sciences》2021,22(24)
The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure—the removal of the plates and screws—can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface. 相似文献