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排序方式: 共有1847条查询结果,搜索用时 46 毫秒
101.
Michael Sander Rainer Gehring Holger Neumann Thomas Jordan 《International Journal of Hydrogen Energy》2012
A new energy storage concept for variable renewable energy, LIQHYSMES, has been proposed which combines the use of LIQuid HYdrogen (LH2) with Superconducting Magnetic Energy Storage (SMES). LH2 with its high volumetric energy density and, compared with compressed hydrogen, increased operational safety is a prime energy carrier for large scale stationary energy storage. But balancing load or supply fluctuations from seconds to several hours with hydrogen alone is difficult due to the response times of the flow control, and an additional short-term electrical energy storage will be needed. For this purpose a compact LIQHYSMES Storage Unit is proposed which integrates the H2 liquefaction part, the LH2 tank and the SMES based on Magnesium Diboride and cooled by the LH2 bath. This allows jointly utilizing the cryogenic infrastructure and reducing the otherwise significant H2 liquefaction losses by introducing a novel process with “cold recovery”. Preliminary target numbers for this process, key parameters for a complete LIQHYSMES model plant, simulations on the anticipated buffering behaviour, a loss analysis and a crude cost estimate are given. 相似文献
102.
The existing theoretical modelling of thermoacoustic oscillations has been studied and applied to the case of tunnel fires. The assumptions of the theoretical model were reviewed. It was found that several assumptions are not applicable to tunnel fires and, hence, suggestions for improvement are given. The correlation which expresses the starting conditions for thermoacoustic oscillations is analysed and dependencies on different parameters are presented. The pulsations documented during the large-scale tests in the Runehamar tunnel in 2003 have also been further analysed. The measurements were compared to the theoretical limiting curve for oscillations, showing good agreement. To further study thermoacoustic oscillations in tunnels, more detailed tests in a model-scale tunnel (1:100) were performed. These tests focused on the circumstances which are required to create thermoacoustic oscillations, i.e. the fire was located at different positions along the tunnel and the air flow rate was varied. The tunnel had a length of 4 m, was 8 cm wide and 6 cm high. The results were in good accordance with the theoretical modelling but showed deviations which were most obvious at very low and high air velocities. Both the starting conditions for thermoacoustic oscillations and cases where the thermoacoustic oscillations suddenly stopped, were observed. These findings led to identification of several points in the theoretical model which need to be improved, and to the development of a strategy to avoid such pulsation in fires. 相似文献
103.
The paper presents simple, physically plausible, but not physically based reflectance models for metals and other specular materials. So far there has been no metallic BRDF model that is easy to compute, suitable for fast importance sampling and is physically plausible. This gap is filled by appropriate modifications of the Phong, Blinn and the Ward models. The Phong and the Blinn models are known not to have metallic characteristics. On the other hand, this paper also shows that the Cook-Torrance and the Ward models are not physically plausible, because of their behavior at grazing angles. We also compare the previous and the newly proposed models. Finally, the generated images demonstrate how the metallic impression can be provided by the new models. 相似文献
104.
Raoudha Haddad Michael Holzinger Reynaldo Villalonga Astrid Neumann Jaan Roots A. Maaref Serge Cosnier 《Carbon》2011,(7):2571-2578
The design of nanostructured biological architectures based on host–guest interactions between β-cyclodextrin and adamantane was investigated on SWCNT coatings using glucose oxidase (GOX) as biomolecule model. β-Cyclodextrin tagged GOX was immobilized on adamantane functionalized carbon nanotubes, deposited on platinum electrodes. Different functionalization techniques to attach “pyrene adamantane” on nanotubes were studied and compared in terms of the performances of the subsequently constructed glucose biosensors. The best results were obtained by dipping the nanotube deposit into a pyrene-adamantane solution followed by electropolymerization of the adsorbed pyrene monolayer. The constructed biosensor exhibited a good linear response toward glucose concentrations between 2 × 10−7 M and 1.6 × 10−3 M. The maximum current density and glucose sensitivity were 154.9 μA cm−2 and 14.4 mA M−1 cm−2, respectively. 相似文献
105.
106.
Genome-Wide Investigation of Multifocal and Unifocal Prostate Cancer—Are They Genetically Different?
Chinyere Ibeawuchi Hartmut Schmidt Reinhard Voss Ulf Titze Mahmoud Abbas Joerg Neumann Elke Eltze Agnes Marije Hoogland Guido Jenster Burkhard Brandt Axel Semjonow 《International journal of molecular sciences》2013,14(6):11816-11829
Prostate cancer is widely observed to be biologically heterogeneous. Its heterogeneity is manifested histologically as multifocal prostate cancer, which is observed more frequently than unifocal prostate cancer. The clinical and prognostic significance of either focal cancer type is not fully established. To investigate prostate cancer heterogeneity, the genetic profiles of multifocal and unifocal prostate cancers were compared. Here, we report observations deduced from tumor-tumor comparison of copy number alteration data of both focal categories. Forty-one fresh frozen prostate cancer foci from 14 multifocal prostate cancers and eight unifocal prostate cancers were subjected to copy number variation analysis with the Affymetrix SNP 6.0 microarray tool. With the investigated cases, tumors obtained from a single prostate exhibited different genetic profiles of variable degrees. Further comparison identified no distinct genetic pattern or signatures specific to multifocal or unifocal prostate cancer. Our findings suggest that samples obtained from multiple sites of a single unifocal prostate cancer show as much genetic heterogeneity and variability as separate tumors obtained from a single multifocal prostate cancer. 相似文献
107.
An uncommon electrolyte, based on sulphosalicylic acid, was used for nickel-cobalt deposition. Some mechanical properties (internal stress and microhardness) and structural properties of the deposits have been presented. High microhardness (nearly 800 HM) with simultaneous low internal stress (about 50 MPa) can be reached. 相似文献
108.
New metallosilicate catalysts were prepared by reacting a silanol capped dendrimer, Si[CH2CH2Si(CH3)2OH]4 with MCp2Cl2 (M = TiIV, MoVI, WVI and VV). The resulting Si[CH2CH2>Si(CH3)2OMCp2Cl]4compounds were incorporated in a silica matrix by the sol–gel method. The catalytic activity of the metallosilicates after calcination revealed excellent activity and selectivity towards epoxidation of alkenes with tert-butylhydroperoxide. Maximum activity was observed with molybdenum-containing materials. Analysis of the catalytic activity revealed that the catalysts were truly heterogeneous. 相似文献
109.
Zita Erika Madi Christian Brandes Georg Neumann David Quist Werner Ruppitsch Rupert Hochegger 《European Food Research and Technology》2013,237(2):125-135
The identification of both approved and non-approved genetically modified organisms (GMOs) is an integral part of GMO biosafety legislation in many countries. One aspect that may affect PCR-based detection of a GMO lies within the analysis of its genetic stability, as sequence alterations or DNA instabilities may impede quantification by PCR. Genetic stability can be analyzed using various methods, yet many of these methods have distinct disadvantages, including low sensitivity. In this study, high resolution melting (HRM) analysis and real-time PCR with Scorpion primers were used as a method to analyze the 3′ end of RR soybeans (RR 40-3-2) in a large number of samples (n = 1,034). No evidence for the occurrence of mutation events was found, implying that the nucleotide sequence of this region is unlikely to be unstable and is well suited as a target for the quantification of RR soybeans. Additionally, and as a preparative work for an optimization of the method, a 174 bp region of the first intron of the Adh1 gene was analyzed in several varieties of maize with different GMO events using the same approach. The results show that 2 alleles are present. In further experiments, the different alleles were cloned into plasmids to generate homozygous plasmids from heterozygous templates in order to generate for a more precise analysis. The overall methodological aim of these studies was to compare HRM analysis with Scorpion primer PCR. Both methods were capable of differentiating between the 2 homozygous and heterozygous alleles. For a better discrimination, however, we conclude that it is most reliable to consider the results of both methods. This dual approach is assumed to be an effective tool as an accurate, high-throughput means of the screening of GMOs for potential genetic instabilities that may interfere with the detection and identification of specific GM events. 相似文献
110.
Measurements of the initiation, growth, and closure behaviour of micro-cracks are reported for one ferritic and one austenitic low strength steel. Interferometric measurements of the COD of small surface cracks were performed with a resolution of 3 nm in order to measure the closure behaviour of micro-cracks. The van der Waals forces between atoms were added numerically in order to calculate the normal as well as the tangential forces acting between closely separated crack faces. The results are discussed in the context of the growth and closure of micro-cracks. 相似文献