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11.
Kati Miettunen Jarkko Etula Tapio Saukkonen Sami Jouttijrvi Janne Halme Jyrki Romu Peter Lund 《Progress in Photovoltaics: Research and Applications》2015,23(8):1045-1056
The main issue in using low cost metals in dye solar cells is the corrosion caused by the liquid electrolyte. Contrary to typical applications of metals, the adverse effects of corrosion in dye solar cells are related to irreversible depletion of charge carriers from the electrolyte rather than consumption of the metal itself. It is calculated that the penetration rate due to corrosion should not exceed 10−4 mpy (a couple of nanometers per year) to ensure device lifetime longer than 1 year. This is 10 000 times slower rate than what is considered to be a general benchmark value for very low corrosion rate in the field of corrosion science and has a major effect on how corrosion should be investigated in the case of dye solar cells. Different methods, their applicability, and limitations to investigate corrosion in dye solar cells are evaluated here. The issue with most techniques is that they can detect metals that are clearly corroding, but they have significant limitations in proving a metal stable. Our investigation shows that the most reliable information on corrosion is obtained from complete dye solar cells that are exposed to working conditions. A combination of color analysis of the electrolyte to such measurement is proposed as a means to extrapolate future performance of the cells and estimate potential lifetimes of the dye solar cells in regards to corrosion. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Andreas Bernas Birgitta Peltopakka Päivi Mäki-Arvela Kari Eränen Tapio Salmi Dmitry Yu. Murzin 《Research on Chemical Intermediates》2007,33(7):645-654
Dimethoxyborane was prepared by the reaction of trimethoxyboroxine, sodium borohydride and trimethyl borate in diethylene
glycol dimethyl ether solvent at 70°C under atmospheric pressure followed by distillation to increase the purity and analyzed
in liquid phase by FT-IR. The concentration of dimethoxyborane was identified by hydrolysis with water, which yields boric
acid, methanol and hydrogen, whereas the generated hydrogen was analyzed by the mass detector of a volumetric flow apparatus.
The FT-IR absorbance peak area showed a linear dependence on dimethoxyborane concentration in the wavenumber range 873 to
950 cm−1 for samples with dimethoxyborane concentrations 0 to 6.2 wt% in trimethyl borate. Data fitting using the least square method
gave an R
2 value of 97%. 相似文献
13.
Catalytic conversion of carbohydrates into value-added products and platform chemicals became a trend in recent years. Microwave activation used in the processes of carbohydrate conversion coupled with the proper choice of catalysts makes it possible to enhance dramatically the efficiency and sometimes the selectivity of catalysts. This mini-review presents a brief literature survey related to state-of-the-art methods developed recently by the world research community to solve the problem of rational conversion of carbohydrates, mostly produced from natural resources and wastes (forestry and agriculture wastes) including production of hydrogen, synthesis gas, furanics, and alcohols. The focus is made on microwave technologies used for processing carbohydrates. Of particular interest is the use of heterogeneous catalysts and hybrid materials in processing carbohydrates. 相似文献
14.
Johan Plomp Mikko Heiskanen Mika Hillukkala Tapio Heikkilä Jari Rehu Niek Lambert Victor van Acht Tom Ahola 《International Journal of Wireless Information Networks》2011,18(4):280-294
In this paper, we highlight considerations for synchronization issues in body area networks. Requirements for the synchronization
accuracy in body area networks depend on the application at hand. Synchronization may be needed for power management, sample
ordering, calculation of stimulus responses and for sensor fusion. This paper provides a theoretical exercise to help understand
the accuracy required for typical human motion sensing. It gives an overview of various synchronisation strategies used and
implemented in prototype systems. Lessons learnt from practical implementations using Bluetooth, an IEEE 802.15.4 proprietary
network and Nanonet are presented to illustrate the principles involved. The discussion provides some considerations and the
requirements for typical WBAN applications. 相似文献
15.
Bernas A Kumar N Mäki-Arvela P Laine E Holmbom B Salmi T Murzin DY 《Chemical communications (Cambridge, England)》2002,(10):1142-1143
Development of a new heterogeneous catalytic pathway for isomerization of linoleic acid to conjugated linoleic acids at mild reaction conditions over Ni/H-MCM-41 in a soluted system. 相似文献
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This paper introduces a generalized design method for polynomial-based interpolation filters. These filters can be implemented
by using a modified Farrow structure, where the fixed finite impulse response (FIR) sub-filters possess either symmetrical
or anti-symmetrical impulse responses. In the proposed approach, the piecewise polynomial impulse response of the interpolation
filter is optimized directly in the frequency domain using either the minimax or least mean square criterion subject to the
given time domain constraints. The length of the impulse response and the degree of the approximating polynomial in polynomial
intervals can be arbitrarily selected. The optimization in the frequency domain makes the proposed design scheme more suitable
for various digital signal processing applications and enables one to synthesize interpolation filters for arbitrary desired
and weighting functions. Most importantly, the interpolation filters can be optimized in a manner similar to that of conventional
linear-phase FIR filters. 相似文献
19.
Andreas Lundell Joakim Westerlund Tapio Westerlund 《Journal of Global Optimization》2009,43(2-3):391-405
In this paper some transformation techniques, based on power transformations, are discussed. The techniques can be applied to solve optimization problems including signomial functions to global optimality. Signomial terms can always be convexified and underestimated using power transformations on the individual variables in the terms. However, often not all variables need to be transformed. A method for minimizing the number of original variables involved in the transformations is, therefore, presented. In order to illustrate how the given method can be integrated into the transformation framework, some mixed integer optimization problems including signomial functions are finally solved to global optimality using the given techniques. 相似文献
20.
Tapio Pulli 《Microelectronics Reliability》1985,25(6):1067-1071
The reliabilities of a three-state device and redundant structures of two such devices are considered, and it is shown that although the two failure modes were equally probable there may be advantages in using redundancy of two devices in series or parallel. It is also shown that the optimal redundant structure of two devices is not solely dependent on the failure mode distribution of the device. 相似文献