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111.
Helfried Näfe Ruhul Amin Fritz Aldinger 《Journal of the American Ceramic Society》2007,90(10):3224-3226
The literature about the thermodynamic properties of NaNbO3 and Na3 NbO4 has mainly been governed by estimations. The only exceptions are two current calorimetric investigations on the standard enthalpy of formation of NaNbO3 and, in addition, an old and inappropriately evaluated study on the carbon dioxide equilibrium gas pressure over the phase mixture NaNbO3 /Na3 NbO4 /Na2 CO3 . Upon reevaluating the latter results, first experimentally proven data on the difference of the Gibbs-free energies have been obtained (715°–822°C): 相似文献
112.
M. Pfeiffer A. Beyer B. Plnnigs A. Nollau T. Fritz K. Leo D. Schlettwein S. Hiller D. Whrle 《Solar Energy Materials & Solar Cells》2000,63(1):83
We present a systematic study on doping of vanadyl- and zinc-pathalocyanine by a fully fluorinated form of tetracyano-quinodimethane as an example of controlled doping of thin organic films by cosublimation of matrix and dopant. The films are characterized in situ by temperature dependent Seebeck and conductivity measurements. We observe a drastic increase of conductivity and a corresponding shift of the Fermi level towards the valence states with increasing dopant concentration. We thus conclude that doping has the potential of both reducing the series resistance and increasing the photovoltage of organic solar cells. As a first step to exploit this potential, we present two different ways of preparing diodes with rectification ratios in excess of 104 using doped phthalocyanines. By adding an undoped interlayer between the contact and the doped layer, we have produced diodes which work already in the strict absence of oxygen and are stable in air. To increase the efficiency of charge carrier generation in photovoltaic cells, we need to use photoactive donor–acceptor-heterojunctions. We present here first examples of pn- and pin-type heterojunctions combining p-doped and nominally undoped layers. 相似文献
113.
In psychological measurement it is important to determine when a particular examinee's test or scale score provides an invalid measure of the trait or attitude being assessed. In this article we present several quantitative indices that have been found to effectively identify some types of inappropriate scores. These measures, termed appropriateness indices, are all derived from item response theory. They are computed directly from the item responses that are combined to form the test or scale of interest; information from other scales or tests is not needed. A decision-theoretic approach to the use of appropriateness indices in selection decisions and theoretical research is introduced. An example is then presented to illustrate how researchers can use appropriateness indices. Finally, we discuss policy options that are available for dealing with individuals who are identified as having inappropriate scores. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
114.
A.C. Zambroni de Souza Fritz W. Mohn Isabella F. Borges Tito R. Ocariz 《Electric Power Systems Research》2011,81(7):1491-1498
This paper investigates the use of the QV and PV curves in the planning scenario, when some system reinforcements and contingency screening are analyzed. The idea is to employ the continuation method to obtain the system load margin and the QV curve to calculate the reactive power reserve associated with each bus. Combining these approaches enables one to identify the system critical area, the actual operating conditions, the most severe contingencies and the most important reinforcements. The methodology proposed may provide important signals to system planners, since the planning is focused under the voltage security point of view. The ideas are tested with the help of some academic systems and two real (a Brazilians and a Paraguayan) systems with all the system limits considered. 相似文献
115.
Comparing Different Synthesis Procedures for Carbide‐Derived Carbon‐Based Structured Catalyst Supports 下载免费PDF全文
Different approaches were analyzed to combine the tuneable micropore structure of carbide‐derived carbons with a foam‐like secondary porosity. The resulting structured catalyst supports were characterized in detail and applied in the model reaction of ethene hydrogenation. Preparation methods studied were dip‐coating using polytetrafluoroethylene as binder on cellular metal structures, a chemical vapor deposition coating of the metal structures with thin carbide layers and subsequent conversion to carbide‐derived carbon, and the partial or full conversion of carbide foams to carbon/carbide composites. For the binder method, optimal parameters for stable slurry preparation as well as for calcination of the slurry were obtained. It could further be demonstrated that the conversion of carbide foams into carbon/carbide composites leads to an appreciation between decreasing mechanical strength and increasing specific surface area. 相似文献
116.
117.
H. Kortum J. Ulsamer G. Vogelpohl Ude W. Fritz Max Jakob 《Forschung im Ingenieurwesen》1933,4(3):150-156
Ohne Zusammenfassung 相似文献
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Hans Erhorn Tomasz Mroz Ove Mørck Fritz Schmidt Lorenz Schoff Kirsten Engelund Thomsen 《Energy and Buildings》2008,40(4):419-428
Educational buildings such as kindergartens, schools and universities display many similar design, operation and maintenance features in most countries. The two most noteworthy similarities amongst these building types are the high energy consumption and the necessity for retrofitting many buildings within this sector. However, studies have shown that during retrofit, energy saving measures are only rarely applied, because the decision-makers lack knowledge of investments and the efficiency of potential energy saving measures. The main goal of the International Energy Agency ECBCS Annex 36 is to provide the educational building decision-makers with sufficient data, information and tools to improve their learning and teaching environments by improving the energy efficiency of their buildings. 相似文献