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481.
Kateřina Macounová Jakub Jirkovský Marina V. Makarova Jiří Franc Petr Krtil 《Journal of Solid State Electrochemistry》2009,13(6):959-965
Nanocrystalline Ru1 − x
Ni
x
O2 − y
with 0.02 < x < 0.30 were prepared by a sol–gel approach at temperatures between 300 and 600 °C. XRD patterns of the prepared materials
indicate a single-phase character conforming to a tetragonal syngony. All prepared materials are sufficiently stable in acid
media and show activity towards oxygen evolution. The activity towards oxygen evolution reaction of the materials with constant
chemical composition decreases with increasing particle size. The increasing Ni content enhances the electrocatalytic activity
in a stepwise manner with abrupt changes for materials containing approximately 5% or 15% of the cationic sites substituted
by Ni. 相似文献
482.
Petr Vítek Jan Jehli?ka Howell G. M. Edwards Kate?ina Osterrothová 《Analytical and bioanalytical chemistry》2009,393(8):1967-1975
Since evaporitic rocks on the Martian surface could (or still can) serve as potential habitats for microbial life on Mars,
there is a reasonable possibility that these rocks may sustain molecular remnants as evidence for the presence of extinct
or extant living organisms on Mars and that β-carotene could be a suitable biomarker. In this paper, Raman microspectrometry
was tested as a nondestructive method of determining the lowest detectable β-carotene content in experimentally prepared evaporitic
matrices—namely, gypsum, halite and epsomite. Two excitation wavelengths were compared—514.5 nm, because of the resonance
Raman enhancement in the carotenoid analysis, and 785 nm, as a more universal wavelength now much used in the detection of
biomolecules terrestrially. Mixtures were measured directly as well as with a laser beam penetrating the crystals of gypsum
and epsomite. We have obtained β-carotene signals at the 0.1 to 10 mg kg−1 level—the number of registered β-carotene Raman bands differed depending on the particular mineral matrix and the excitation
wavelength. Concentrations of β-carotene of about one order of magnitude higher were identified when analysed through single
crystals of gypsum and epsomite, respectively. 相似文献
483.
Helms Tillery K Brown CA Bacon SP 《The Journal of the Acoustical Society of America》2012,131(1):416-423
Cochlear implant users report difficulty understanding speech in both noisy and reverberant environments. Electric-acoustic stimulation (EAS) is known to improve speech intelligibility in noise. However, little is known about the potential benefits of EAS in reverberation, or about how such benefits relate to those observed in noise. The present study used EAS simulations to examine these questions. Sentences were convolved with impulse responses from a model of a room whose estimated reverberation times were varied from 0 to 1 sec. These reverberated stimuli were then vocoded to simulate electric stimulation, or presented as a combination of vocoder plus low-pass filtered speech to simulate EAS. Monaural sentence recognition scores were measured in two conditions: reverberated speech and speech in a reverberated noise. The long-term spectrum and amplitude modulations of the noise were equated to the reverberant energy, allowing a comparison of the effects of the interferer (speech vs noise). Results indicate that, at least in simulation, (1) EAS provides significant benefit in reverberation; (2) the benefits of EAS in reverberation may be underestimated by those in a comparable noise; and (3) the EAS benefit in reverberation likely arises from partially preserved cues in this background accessible via the low-frequency acoustic component. 相似文献
484.
Nantanit Wanichacheva Krit Setthakarn Narupon Prapawattanapol Oranual Hanmeng Vannajan Sanghiran Lee Kate Grudpan 《Journal of luminescence》2012,132(1):35-40
Two novel macromolecules based on 2-[3-(2-aminoethylsulfanyl)propylsulfanyl]ethanamine covalently bound to one and two units of rhodamine-B moieties, 1 and 2, were prepared and utilized as fluoroionophores and chromophores for the optical detection of Hg2+ ions. The sensors were readily prepared by a conventional two-step synthesis. Especially, sensor 1 exhibits high sensitivity and selective OFF–ON fluorescence enhancement and chromogenic change upon binding to Hg2+, which served as a “naked-eye” indicator by a noticeable color change of the solution (from colorless to pink–red color). 1 is shown to discriminate various competing metal ions, particularly Ag+ and Cu2+, as well as Cd2+, Na+, Li+, K+, Ba2+, Co2+, Ni2+, Mg2+, Mn2+ and Al3+, with a detection limit of 10 ppb. 相似文献
485.
Anil Disale Chittaranjan Nayak Nagesh Suryawanshi Nitin Jadhav Umesh Jagdale Gunwant Kate Sunil Thakare Shri Prakash Pandey Prakhakar Sharma Amit Saxena 《Macromolecular Symposia》2024,413(1):2300009
Industrial waste locks are used as raw materials to reduce harmful effects on the environment and improve environmental performance. Marble clay powder can be used as a filling aid and can fill voids in concrete structures. This article will show you how to use a maximum natural sand alternative in concrete with marble powder and quarry dust. The challenge of the 21st century is to change to a new form that can support the natural system. This necessitates a radical rethinking of how to give the community infrastructure and housing. Making a concerted effort to develop novel, innovative, and alternative construction materials may be necessary. Jungles of concrete around cause's impact on the Environment and it would result in climate change. Mankind must avoid the use of things that are detrimental to the environment. So in this paper, it is decided to address the issue by adopting the use of the green concrete concept which is environmentally friendly. Green concrete is concrete made up using industrial wastes such as marble powder, quarry dust, wood ash, paper pulp, etc. Green concrete, which is capable of sustainable development, helps to reduce the consumption of natural resources, energy use, and environmental pollution. Green concrete is more cost-effective than ordinary concrete and reduces the cost of resultant concrete by 14%–20%. It is also observed that the alkali-aggregate reaction and sulfate attack resistance of concrete are both significantly improved. Green concrete is a useful tool for lowering environmental pollution and enhancing concrete's resistance to harsh conditions. All stages of infrastructure construction and rehabilitation will follow this trend of using new cement and techniques. Green concrete's adaptability and its performance derivatives will meet a variety of future needs. 相似文献